mybatis-plus拦截器、字段填充器、类型处理器、表名替换、SqlInjector(联合主键处理)
作者：LL小蜗牛
本文主要介绍了mybatis-plus拦截器、字段填充器、类型处理器、表名替换、SqlInjector(联合主键处理)，文中通过示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下
最近有个练手的小例子，大概就是配置两个数据源，从一个数据源读取数据写到另一个数据源，虽然最后做了出来，但是不支持事务。。。就当是对mybatis-plus/mybatis组件使用方式的记录吧，本次例子使用的仍是mybatis-plus
回忆一下mybatis核心对象：
- Configuration 初始化基础配置，比如MyBatis的别名等，一些重要的类型对象，如，插件，映射器，ObjectFactory和typeHandler对象，MyBatis所有的配置信息都维持在Configuration对象之中
- SqlSessionFactory SqlSession工厂
- SqlSession 作为MyBatis工作的主要顶层API，表示和数据库交互的会话，完成必要数据库增删改查功能
- Executor MyBatis执行器，是MyBatis 调度的核心，负责SQL语句的生成和查询缓存的维护
- StatementHandler 封装了JDBC Statement操作，负责对JDBC statement 的操作，如设置参数、将Statement结果集转换成List集合。
- ParameterHandler 负责对用户传递的参数转换成JDBC Statement 所需要的参数，
- ResultSetHandler 负责将JDBC返回的ResultSet结果集对象转换成List类型的集合；
- TypeHandler 负责java数据类型和jdbc数据类型之间的映射和转换
- MappedStatement MappedStatement维护了一条<select|update|delete|insert>节点的封装，
- SqlSource 负责根据用户传递的parameterObject，动态地生成SQL语句，将信息封装到BoundSql对象中，并返回
- BoundSql 表示动态生成的SQL语句以及相应的参数信息
组件介绍
mybatis可以在执行语句的过程中对特定对象进行拦截调用，主要有四个
- Executor (update, query, flushStatements, commit, rollback, getTransaction, close, isClosed) 处理增删改查
- ParameterHandler (getParameterObject, setParameters) 设置预编译参数
- ResultSetHandler (handleResultSets, handleOutputParameters) 处理结果
- StatementHandler (prepare, parameterize, batch, update, query) 处理sql预编译，设置参数
这四个是可以拦截的对象,大概的做法是实现mybatis拦截器的接口并在上面添加注解来确定拦截那些方法
下面是接口Interceptor所要实现的方法，setPropertites可以用来初始化，而plugin则包装目标对象供拦截器处理，基于动态代理实现，Plugin类是动态代理类，对实现Interceptor的接口的类进行处理，而实现的拦截器会被加入到拦截器链进行处理
Object intercept(Invocation var1) throws Throwable;
default Object plugin(Object target) {
return Plugin.wrap(target, this);
}
default void setProperties(Properties properties) {
}
plugin.warp方法
拦截器链：
public class InterceptorChain {
private final List<Interceptor> interceptors = new ArrayList();
public InterceptorChain() {
}
public Object pluginAll(Object target) {
Interceptor interceptor;
for(Iterator var2 = this.interceptors.iterator(); var2.hasNext(); target = interceptor.plugin(target)) {
interceptor = (Interceptor)var2.next();
}
return target;
}
public void addInterceptor(Interceptor interceptor) {
this.interceptors.add(interceptor);
}
public List<Interceptor> getInterceptors() {
return Collections.unmodifiableList(this.interceptors);
}
}
并在handler里面添加这些拦截器类，执行pluginAll方法，返回一个经过代理链处理的对象
实现该接口以后，要添加注解来表明拦截哪些方法，方法则是上面四个对象的拥有的方法。下面这个注解则是指定了拦截哪些对象的哪个方法，args则是被拦截方法的参数
public @interface Signature {
Class<?> type();
String method();
Class<?>[] args();
}
比如这个例子
@Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class})
Signature注解就对应上面的接口、方法及其参数，然后在拦截器添加一个@Intercepts，这个注解的内容是Signature注解数组
有了拦截器，初步想法是根据方法拦截，如果select则使用读数据源，增删改则使用写数据源，这个其实原理和之前写的一篇代码级别读写分离很相似，也是通过ThreadLocal存放当前线程的数据源，然后通过拦截器来判断用哪个数据源，交由AbstarctRoutingDataSource来根据ThreadLoacl里面的值来处理。
但是有个问题，两个数据源转换，表名、字段名不一定相等，比如从pgsql的一个叫user_info表里的数据转到mysql叫user表的数据，字段名都不相同
我的处理方法是查询对象的目标的字段名为准，然后给每个字段一个注解指向修改对象的数据源表字段名，如果查询目标表没有插入目标表的字段，便在select的时候默认select null或者用代码限定查询的字段。这里首先先定义了三个注解，分别对应查、改相应的数据源、表名、字段
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface TranDB {
DBType from();
DBType to();
Class object();
}
public @interface TranField {
String from() default "";
String to();
String empty = "null";
}
public @interface TranTable {
String from();
String to();
}
User类
@TranTable(from = "user_info", to = "user")
public class User {
@TranField(to = "id")
@TableId
private Integer userId;
@TranField(to = "wx_nickname")
private String userAccount;
@TranField(to = "roles")
private String mobile;
@TranField(from=TranField.empty,to="create_time")
private Date createTime;
@TranField(from=TranField.empty,to="update_time")
private Date updateTime;
@TranField(from=TranField.empty,to="bonus")
private Integer bonus;
@TranField(to="wx_id")
private String[] test;
}
UserMapper
@TranDB(from = DBType.PGSQL,to=DBType.MYSQL,object=User.class)
public interface UserMapper extends BaseMapper<User> {
}
这里添加一个缓存mapper信息类，方便在拦截器中调用，其中有个成员变量是用来存储mapperName对应的TranDB注解信息，拦截器通过拦截的方法获取mapper名称，再通过这个mapper信息类获取他的TranDB注解，这个注解里面有对应的实体class，可以用来获取字段信息注解及表名信息注解，而另一个成员变量则是用来存放待会说到的表名替换，这里面实现了两个接口，一个通过spring容器加载资源的接口，另一个则是用来初始化bean的。
package com.trendy.task.transport.config;
import com.baomidou.mybatisplus.extension.parsers.ITableNameHandler;
import com.trendy.task.transport.annotations.TranDB;
import com.trendy.task.transport.handler.SelfTableNameHandler;
import com.trendy.task.transport.util.CamelHumpUtils;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternUtils;
import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import java.util.*;
/**
* Mapper信息缓存类
*/
public class MapperAuxFeatureMap implements ResourceLoaderAware, InitializingBean {
private static ResourceLoader resourceLoader;
@Value("${tran.mapperlocation}")
public String MAPPER_LOCATION ;
public static final String TABLEPREFIX="t_";
//表名处理
public Map<String, ITableNameHandler> tableNameHandlerMap;
//mapper文件的注解
public Map<String, TranDB> mapperTranDbMap;
//通过方法获取mapper名称
public static String getMapperNameFromMethodName(String source){
int end = source.lastIndexOf(".") + 1;
String mapper = source.substring(0, end - 1);
mapper = mapper.substring(mapper.lastIndexOf(".") + 1);
return mapper;
}
@Override
public void setResourceLoader(ResourceLoader resourceLoader) {
MapperAuxFeatureMap.resourceLoader=resourceLoader;
}
@Override
public void afterPropertiesSet() throws Exception {
ResourcePatternResolver resolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);
MetadataReaderFactory metaReader = new CachingMetadataReaderFactory(resourceLoader);
Resource[] resources = resolver.getResources("classpath*:"+MAPPER_LOCATION.replace(".","/")+"/**/*.class");
mapperTranDbMap = new HashMap<>();
tableNameHandlerMap = new HashMap<>();
for (Resource r : resources) {
MetadataReader reader = metaReader.getMetadataReader(r);
String className = reader.getClassMetadata().getClassName();
Class<?> c = Class.forName(className);
if (c.isAnnotationPresent(TranDB.class)) {
String name = c.getSimpleName();
TranDB tranDB = c.getAnnotation(TranDB.class);
mapperTranDbMap.put(name, tranDB);
String value = tranDB.object().getSimpleName();
tableNameHandlerMap.put(TABLEPREFIX+ CamelHumpUtils.humpToLine(value),new SelfTableNameHandler(tranDB.object()));
}
}
}
}
替换数据源的部分代码，对query和update（即增删改）方法进行拦截，改方法使用mysql数据源，查方法使用pgsql数据源
package com.trendy.task.transport.dyma;
import com.trendy.task.transport.annotations.TranDB;
import com.trendy.task.transport.config.MapperAuxFeatureMap;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlCommandType;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import java.util.Properties;
/**
* @author: lele
* @date: 2019/10/23 下午4:24
*/
@Intercepts({
@Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}),
@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class,
RowBounds.class, ResultHandler.class})
})
public class DynamicDataSourceInterceptor implements Interceptor {
private MapperAuxFeatureMap mapperAuxFeatureMap;
public DynamicDataSourceInterceptor(MapperAuxFeatureMap mapperAuxFeatureMap) {
this.mapperAuxFeatureMap = mapperAuxFeatureMap;
}
@Override
public Object intercept(Invocation invocation) throws Throwable {
//如果读取数据，使用From的库，否则使用To库
DBType db =null;
Object[] objects = invocation.getArgs();
MappedStatement statement = (MappedStatement) objects[0];
String mapper = MapperAuxFeatureMap.getMapperNameFromMethodName(statement.getId());
TranDB tranDB = mapperAuxFeatureMap.mapperTranDbMap.get(mapper);
if (statement.getSqlCommandType().equals(SqlCommandType.SELECT)) {
db = tranDB.from();
} else {
db = tranDB.to();
}
DynamicDataSourceHolder.setDbType(db);
return invocation.proceed();
}
@Override
public Object plugin(Object o) {
if (o instanceof Executor) {
return Plugin.wrap(o, this);
} else {
return o;
}
}
@Override
public void setProperties(Properties properties) {
}
}
然后对字段进行修改的拦截器，这里为什么要继承AbstactSqlPaserHandler呢，因为可以复用他的方法，以及为后来加入表名替换的类做准备，这里的流程是获取原来字段的名字，并改为TranField的to所存储的内容
package com.trendy.task.transport.handler;
import com.baomidou.mybatisplus.core.toolkit.PluginUtils;
import com.baomidou.mybatisplus.extension.handlers.AbstractSqlParserHandler;
import com.trendy.task.transport.annotations.TranDB;
import com.trendy.task.transport.annotations.TranField;
import com.trendy.task.transport.config.MapperAuxFeatureMap;
import com.trendy.task.transport.util.CamelHumpUtils;
import org.apache.ibatis.executor.statement.StatementHandler;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlCommandType;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.reflection.SystemMetaObject;
import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.Statement;
import java.util.HashMap;
import java.util.Map;
/**
* @author: lele
* @date: 2019/10/23 下午5:12
*/
@Intercepts({
@Signature(
type = StatementHandler.class,
method = "prepare",
args = {Connection.class, Integer.class}
),
@Signature(
type = StatementHandler.class,
method = "update",
args = {Statement.class}
),
@Signature(
type = StatementHandler.class,
method = "batch",
args = {Statement.class}
)
})
public class FieldHandler extends AbstractSqlParserHandler implements Interceptor {
private MapperAuxFeatureMap mapperAuxFeatureMap;
public FieldHandler(MapperAuxFeatureMap mapperAuxFeatureMap) {
this.mapperAuxFeatureMap = mapperAuxFeatureMap;
}
@Override
public Object plugin(Object target) {
return target instanceof StatementHandler ? Plugin.wrap(target, this) : target;
}
@Override
public Object intercept(Invocation invocation) throws Throwable {
StatementHandler statementHandler = PluginUtils.realTarget(invocation.getTarget());
MetaObject metaObject = SystemMetaObject.forObject(statementHandler);
super.sqlParser(metaObject);
MappedStatement mappedStatement = (MappedStatement) metaObject.getValue("delegate.mappedStatement");
BoundSql boundSql = (BoundSql) metaObject.getValue("delegate.boundSql");
Boolean select = mappedStatement.getSqlCommandType().equals(SqlCommandType.SELECT);
if (!select) {
//通过获取mapper名称从缓存类中获取对应的注解
String mapperName = MapperAuxFeatureMap.getMapperNameFromMethodName(mappedStatement.getId());
TranDB tranDB = mapperAuxFeatureMap.mapperTranDbMap.get(mapperName);
//获取类的所有属性
Class clazz = tranDB.object();
Map<String, Field> mapField = new HashMap<>(clazz.getFields().length);
while (!clazz.equals(Object.class)) {
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
field.setAccessible(true);
mapField.put(field.getName(), field);
}
clazz = clazz.getSuperclass();
}
//替换sql
String sql = boundSql.getSql();
for (Map.Entry<String, Field> entry : mapField.entrySet()) {
String sqlFieldName = CamelHumpUtils.humpToLine(entry.getKey());
if (sql.contains(sqlFieldName)) {
String from = entry.getValue().getAnnotation(TranField.class).to();
sql = sql.replaceAll(sqlFieldName, from);
}
}
metaObject.setValue("delegate.boundSql.sql", sql);
}
return invocation.proceed();
}
}
现在还有一个问题要处理，就是表名替换，但是这个有个小坑，这个功能也相当于上面替换sql的功能比如insert into user(user_info,user_id) values ...,比如把user这个表名替换为user_info这个表来执行，此时的插入语句会把所有user的替换成user_info,这时候官方的建议是用@TableName这个注解更改表名避免出现这个情况
表名处理器
使用：实现ITableNameHandler，并实现接口方法返回一个表名字
package com.trendy.task.transport.handler;
import com.baomidou.mybatisplus.extension.parsers.ITableNameHandler;
import com.trendy.task.transport.annotations.TranTable;
import org.apache.ibatis.reflection.MetaObject;
/**
* @author: lele
* @date: 2019/10/24 下午2:39
* 表名替换的handler
*/
public class SelfTableNameHandler implements ITableNameHandler {
private final Class clazz;
public SelfTableNameHandler(Class clazz) {
this.clazz = clazz;
}
@Override
public String dynamicTableName(MetaObject metaObject, String sql, String tableName) {
TranTable t = (TranTable) clazz.getAnnotation(TranTable.class);
if (sql.toLowerCase().startsWith("select")) {
return t.from();
} else {
return t.to();
}
}
}
也可以注入到mp自带的分页那个拦截器中
@Bean
public FieldHandler fieldHandler() {
FieldHandler f = new FieldHandler(mapperAuxFeatureMap());
DynamicTableNameParser t = new DynamicTableNameParser();
t.setTableNameHandlerMap(mapperAuxFeatureMap().tableNameHandlerMap);
f.setSqlParserList(Collections.singletonList(t));
return f;
}
字段填充器
mysql的表里有创建时间、修改时间、积分，对于这些字段，而pgsql表里面没有，这时候想在插入时使用一个默认的值，这时候可以使用字段填充器
做法：实现MetaObjectHandler接口，并重写里面的方法，然后在字段的@TableField的fill类型里面说明需要填充时情况
例子，对createTime，updateTime，bouns进行默认填充，使用getFieldValueByName和setFieldValByName方法进行赋值
package com.trendy.task.transport.handler;
import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;
import java.util.Date;
/**
* @author lulu
* @Date 2019/10/24 23:15
* 自动填充的handler
*/
public class DefaultFieldValueHandler implements MetaObjectHandler {
public static final String CREATETIME = "createTime";
public static final String UPDATETIME = "updateTime";
public static final String BOUNS = "bonus";
private void handle(String name, MetaObject metaObject, Object target) {
Object o = getFieldValByName(name, metaObject);
if (o == null) {
setFieldValByName(name, target, metaObject);
}
}
@Override
public void insertFill(MetaObject metaObject) {
handle(CREATETIME, metaObject, new Date());
handle(UPDATETIME, metaObject, new Date());
handle(BOUNS, metaObject, 500);
}
@Override
public void updateFill(MetaObject metaObject) {
handle(UPDATETIME, metaObject, new Date());
}
}
然后为user添加注解@TableField的注解
@TranField(from=TranField.empty,to="create_time")
@TableField(fill = FieldFill.INSERT)
private Date createTime;
@TranField(from=TranField.empty,to="update_time")
@TableField(fill = FieldFill.INSERT_UPDATE)
private Date updateTime;
@TranField(from=TranField.empty,to="bonus")
@TableField(fill= FieldFill.INSERT)
private Integer bonus;
然后在全局配置中加入这个字段填充器类
@Bean
public GlobalConfig globalConfig() {
GlobalConfig globalConfig = new GlobalConfig();
globalConfig.setBanner(false);
globalConfig.setMetaObjectHandler(defaultFieldValueHandler());
return globalConfig;
}
工厂类配置上全局配置 sqlSessionFactory.setGlobalConfig(globalConfig());
类型处理器
类型处理器，用于 JavaType 与 JdbcType 之间的转换，用于 PreparedStatement 设置参数值和从 ResultSet 或 CallableStatement 中取出一个值，比如把String、Integer、Long、Double放到数据库里面用逗号分隔形式存储，此时可以
自定义类型处理器，这里针对上面四个对象数组实现类型转换处理，setxxx方法主要是对参数进行处理，然后把处理后的结果放入数据库中，而get方法则处理从数据库取出来的数据该如何处理，这里接受一个lambda函数作为方法转换，即字符串-》目标类型，这里定义一个抽象类统一处理方法，然后具体转换方法由子类实现
package com.trendy.task.transport.handler;
import org.apache.ibatis.type.BaseTypeHandler;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.MappedJdbcTypes;
import org.apache.ibatis.type.MappedTypes;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.function.Function;
/**
* @author lulu
* @Date 2019/10/25 21:46
*/
//@MappedJdbcTypes({})表明处理哪种jdbc类型
@MappedTypes(Object[].class)//表明处理哪种javatype
public abstract class AbstractArrayTypeHandler<T> extends BaseTypeHandler<Object[]> {
//这里接受一个lambdah函数做转换处理
private final Function<String,T> method;
public AbstractArrayTypeHandler(Function<String,T> method){
this.method=method;
}
@Override
public void setNonNullParameter(PreparedStatement preparedStatement, int i, Object[] objects, JdbcType jdbcType) throws SQLException {
StringBuilder sb=new StringBuilder();
for(Object o:objects){
sb.append(o.toString()+",");
}
sb.deleteCharAt(sb.length()-1);
preparedStatement.setString(i,sb.toString());
}
@Override
public T[] getNullableResult(ResultSet resultSet, String s) throws SQLException {
return getArray(resultSet.getString(s));
}
@Override
public T[] getNullableResult(ResultSet resultSet, int i) throws SQLException {
return getArray(resultSet.getString(i));
}
@Override
public Object[] getNullableResult(CallableStatement callableStatement, int i) throws SQLException {
return getArray(callableStatement.getString(i));
}
protected T[] getArray(String source){
if(source==null){
return null;
}
String[] resString=source.split(",");
if(this.method==null){
return (T[])resString;
}
T[] resArray= (T[]) new Object[resString.length];
for (int i = 0; i < resString.length; i++) {
resArray[i]=method.apply(resString[i]);
}
return resArray;
}
}
然后定义一个工厂存放子类
package com.trendy.task.transport.handler;
import java.util.function.Function;
/**
* @author lulu
* @Date 2019/10/25 22:33
*/
public interface ArrayTypeHandlerFactory {
class IntegerArrayTypeHandler extends AbstractArrayTypeHandler<Integer>{
public IntegerArrayTypeHandler() {
super(Integer::parseInt);
}
}
class DoubleArrayTypeHandler extends AbstractArrayTypeHandler<Double>{
public DoubleArrayTypeHandler(){
super(Double::parseDouble);
}
}
class LongArrayTypeHandler extends AbstractArrayTypeHandler<Long>{
public LongArrayTypeHandler(){
super(Long::parseLong);
}
}
class StringArrayTypeHandler extends AbstractArrayTypeHandler<String>{
public StringArrayTypeHandler(){
super(null);
}
}
}
指定处理类型
@TableField(typeHandler = ArrayTypeHandlerFactory.StringArrayTypeHandler.class)
好了，现在来测试下，
@Test
public void selectById() {
List<User> userList = userService.list(new LambdaQueryWrapper<User>().select(User::getUserId,User::getMobile,User::getUserAccount,User::getTest));
userService.saveBatch(userList);
}
大概就到这里，代码完整版的github地址：GitHub - 97lele/transport
但是这个有个缺陷，就是不支持事务，还有saveOrUpdate方法也不支持，因为两个数据源都不一样，他是先查，看是否有再做更新或者插入操作，这些问题仍需解决，且当作一个使用方法记录的小例子吧
补充
mybatis-plus默认的baseMapper不支持批量的插入和更新，有时候会为了这个批量的方法去继承serviceImpl类，而这个类有没有其他的业务代码在里面，继承仅仅是为了获取批量操作的方法，会显得这个类有点”贫血“
对于这种情况，偶然看到一个开源的项目onemall对BaseMapper做了扩展，使它支持了批量插入的做法，在此基础下，我也做了一定的扩展
根据自己的见解，简单描述下流程：
核心就是自定义一个sql自动注入器，mybatis-plus会扫描mapper类 ,为每个mapper类构造一个MappedStatement（相当于mapper里的一个sql）
添加到配置类里面（具体在下面(2)）,只会在初始化时候执行一次，而我们要做的，就是把某个特定mapper，注入我们想要的模板方法
具体注入在MybatisMapperAnnotationBuilder，注入动态sql,getSqlInjector获取sql注入器，并为当前的MapperBuilderAssistant对象(类似于mapper)注入mappedStatement(sql)
（1）注入开始，里面的inspectInject就是
inspectInject就会把abstractMethod一一注入进去
public void inspectInject(MapperBuilderAssistant builderAssistant, Class<?> mapperClass) {
Class<?> modelClass = extractModelClass(mapperClass);
if (modelClass != null) {
String className = mapperClass.toString();
Set<String> mapperRegistryCache = GlobalConfigUtils.getMapperRegistryCache(builderAssistant.getConfiguration());
if (!mapperRegistryCache.contains(className)) {
List<AbstractMethod> methodList = this.getMethodList(mapperClass);
if (CollectionUtils.isNotEmpty(methodList)) {
TableInfo tableInfo = TableInfoHelper.initTableInfo(builderAssistant, modelClass);
// 循环注入自定义方法
methodList.forEach(m -> m.inject(builderAssistant, mapperClass, modelClass, tableInfo));
} else {
logger.debug(mapperClass.toString() + ", No effective injection method was found.");
}
mapperRegistryCache.add(className);
}
}
}
（(2)抽象方法注入类,最终放到configuration类缓存，形成一个sql
具体看看AbstractMethod的实现类，而默认的DefaultSqlInject类就有我们baseMapper所包含的默认方法,我们要添加多两个方法，批量更新和批量插入
下面开始编码
首先继承AbstarctMethod类，实现我们想注入的sql模板
对于批量插入，使用 insert into table columns values (values),(values),(values)
对于批量更新，使用 update table set xx=xx,xx=xx where xx=xx;update table set xx=xx,xx=xx where xx=xx;update table set xx=xx,xx=xx where xx=xx;进行分号分割
因为要用到标签解析的功能，需要用script包裹起来。
具体初始化模板如下, 对其进行填充
public enum CustomSqlMethodEnum {
/**
* 批量插入
*/
INSERT_BATCH("insertBatch",
"批量插入",
"<script>\n"
+ "INSERT INTO %s %s VALUES \n"
+ "<foreach collection=\"collection\" item=\"item\" separator=\",\"> %s\n </foreach>\n"
+ "</script>"),
/**
* 批量更新
*/
UPDATE_BATCH("updateBatchByIds",
"批量更新",
"<script>\n" +
"<foreach collection=\"collection\" item=\"item\" separator=\";\"> update %s set %s where %s </foreach>\n"
+ "</script>"
),
/**
* 根据联合键查询
*/
SELECT_BY_COMPOSEKEYS("selectByComposeKeys",
"联合主键查询",
"<script>" +
" select <choose> <when test=\"ew!=null and ew.sqlSelect != null and ew.sqlSelect != ''\"> ${ew.sqlSelect} </when> <otherwise> * </otherwise> </choose> from %s "
+ "<where> <foreach collection=\"collection\" item=\"item\" open=\"(\" close=\")\" separator=\"or\"> ( %s ) </foreach> <if test=\"ew!=null and ew.sqlSegment != null and ew.sqlSegment != ''\">\n" +
"AND ${ew.sqlSegment}\n" +
"</if> </where> </script>"
),
/**
* 根据联合键查询
*/
SELECT_IDS_BY_COMPOSEKEYS("selectIdsByComposeKeys",
"联合主键查询id",
"<script>" +
" select %s from %s "
+ "<where> <foreach collection=\"collection\" item=\"item\" open=\"(\" close=\")\" separator=\"or\"> ( %s ) </foreach> </where> </script>"
),
/**
* 根据联合主键删除
*/
DELETE_BY_COMPOSEKEYS("deleteByComposeKeys",
"联合主键删除",
"<script>" +
" delete from %s "
+ "<where> <foreach collection=\"collection\" item=\"item\" open=\"(\" close=\")\" separator=\"or\"> ( %s ) </foreach> </where> </script>"
),
/**
* 根据联合主键更新
*/
UPDATE_BY_COMPOSEKEYS("updateByComposeKeys"
, "联合主键批量修改",
"<script>\n" +
"<foreach collection=\"collection\" item=\"item\" separator=\";\"> update %s set %s where %s </foreach>\n"
+ "</script>"
);
private final String method;
private final String desc;
private final String sql;
CustomSqlMethodEnum(String method, String desc, String sql) {
this.method = method;
this.desc = desc;
this.sql = sql;
}
public String getMethod() {
return method;
}
public String getDesc() {
return desc;
}
public String getSql() {
return sql;
}
}
下面是构造批量插入和更新的代码逻辑
批量插入：主要是构造——表名、插入列、插入值,这里为了防止覆盖数据库默认值，也可以做if test 的那种判空，来取消插入，不过比较麻烦，这里就不做了
public class InsertBatch extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
KeyGenerator keyGenerator = new NoKeyGenerator();
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.INSERT_BATCH;
// ==== 拼接 sql 模板 ==============
StringBuilder columnScriptBuilder = new StringBuilder(LEFT_BRACKET);
StringBuilder valuesScriptBuilder = new StringBuilder(LEFT_BRACKET);
// 主键拼接
if (StringUtils.isNotBlank(tableInfo.getKeyColumn())) {
//(x1,x2,x3
columnScriptBuilder.append(tableInfo.getKeyColumn()).append(COMMA);
//(item.xx,item.xx
valuesScriptBuilder.append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + tableInfo.getKeyProperty())).append(COMMA);
}
// 普通字段拼接
List<TableFieldInfo> fieldList = tableInfo.getFieldList();
for (TableFieldInfo fieldInfo : fieldList) {
//有更新默认填充器的不参与赋值
if (!fieldInfo.isWithInsertFill() && fieldInfo.isWithUpdateFill()) {
continue;
}
columnScriptBuilder.append(fieldInfo.getColumn()).append(COMMA);
valuesScriptBuilder.append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString())).append(COMMA);
}
// 替换多余的逗号为括号
//(x1,x2)
columnScriptBuilder.setCharAt(columnScriptBuilder.length() - 1, ')');
//(item.xx,item.xx2)
valuesScriptBuilder.setCharAt(valuesScriptBuilder.length() - 1, ')');
// sql 模板占位符替换
String columnScript = columnScriptBuilder.toString();
String valuesScript = valuesScriptBuilder.toString();
String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), columnScript, valuesScript);
// === mybatis 主键逻辑处理：主键生成策略，以及主键回填=======
String keyColumn = null;
String keyProperty = null;
// 表包含主键处理逻辑,如果不包含主键当普通字段处理
if (StringUtils.isNotBlank(tableInfo.getKeyProperty())) {
if (tableInfo.getIdType() == IdType.AUTO) {
/** 自增主键 */
keyGenerator = new Jdbc3KeyGenerator();
keyProperty = tableInfo.getKeyProperty();
keyColumn = tableInfo.getKeyColumn();
} else {
if (null != tableInfo.getKeySequence()) {
keyGenerator = TableInfoHelper.genKeyGenerator(sqlMethod.getMethod(), tableInfo, builderAssistant);
keyProperty = tableInfo.getKeyProperty();
keyColumn = tableInfo.getKeyColumn();
}
}
}
// 模板写入
SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
return this.addInsertMappedStatement(mapperClass, modelClass, sqlMethod.getMethod(), sqlSource, keyGenerator, keyProperty, keyColumn);
}
}
更新sql构造，这里要注意字段上的字段策略（FieldStrategy），附上处理类
public class UpdateBatchByIds extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.UPDATE_BATCH;
/**
* update table set <if test ="item.pro!=null">key1=#{item.pro}</if>, key2=#{item.pro2} where keycolom = %s
* */
StringBuilder withChevScript = new StringBuilder();
StringBuilder lastFiledScriptBuilder=new StringBuilder();
StringBuilder keyScriptBuilder = new StringBuilder();
if (StringUtils.isNotBlank(tableInfo.getKeyColumn())) {
keyScriptBuilder.append(tableInfo.getKeyColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + tableInfo.getKeyProperty()));
}
List<TableFieldInfo> fieldList = tableInfo.getFieldList();
for (int i = 0; i < fieldList.size(); i++) {
TableFieldInfo fieldInfo = fieldList.get(i);
Boolean isLast=(i==(fieldList.size()-1));
//有插入默认填充器的不参与赋值
if (fieldInfo.isWithInsertFill() && !fieldInfo.isWithUpdateFill()) {
continue;
}
boolean change = false;
if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_NULL) && !fieldInfo.isWithUpdateFill()) {
SQLConditionWrapper.appendNotNull(withChevScript, fieldInfo.getProperty());
change = true;
}
if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_EMPTY) && !fieldInfo.isWithUpdateFill()) {
SQLConditionWrapper.appendNotEmpty(withChevScript, fieldInfo.getProperty());
change = true;
}
if (change) {
withChevScript.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString()));
withChevScript.append(COMMA).append("</if>");
if(isLast&&lastFiledScriptBuilder.length()==0){
//如果没有其他字段替补，弄个占位的，不然会出现语法错误的情况
withChevScript.append(tableInfo.getKeyColumn()).append(EQUALS).append(tableInfo.getKeyColumn());
}
}else{
lastFiledScriptBuilder.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString())).append(COMMA);
}
}
//处理多余的逗号
if(!StringUtils.isBlank(lastFiledScriptBuilder)&&!StringUtils.isBlank(withChevScript)){
int leftChevIndex= withChevScript.lastIndexOf(LEFT_CHEV);
if(withChevScript.charAt(leftChevIndex-1)!=','){
withChevScript.replace(leftChevIndex,leftChevIndex+1,",<");
}
if(lastFiledScriptBuilder.lastIndexOf(COMMA)==lastFiledScriptBuilder.length()-1){
lastFiledScriptBuilder.deleteCharAt(lastFiledScriptBuilder.length()-1);
}
}
withChevScript.append(lastFiledScriptBuilder);
// sql 模板占位符替换
String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), withChevScript, keyScriptBuilder);
// 模板写入
SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
return this.addUpdateMappedStatement(mapperClass, modelClass, sqlMethod.getMethod(), sqlSource);
}
}
public class SQLConditionWrapper {
public final static String ITEM = "item";
public static StringBuilder appendNotNull(StringBuilder builder, String property) {
return appendEnd(appendStart(builder, getCondition(property)));
}
public static StringBuilder appendNotEmpty(StringBuilder builder, String property) {
StringBuilder condition = getCondition(property);
StringBuilder append = appendStart(builder, condition)
.append(" ").append(AND).append(" ").append(condition).append(EXCLAMATION_MARK).append(EQUALS).append(" ").append("''");
return appendEnd(append);
}
private static StringBuilder appendEnd(StringBuilder builder) {
builder.append("\"")
.append(RIGHT_CHEV);
return builder;
}
private static StringBuilder appendStart(StringBuilder builder, StringBuilder item) {
builder.append(LEFT_CHEV)
.append("if test=\"")
.append(item).append(EXCLAMATION_MARK).append(EQUALS).append(NULL);
return builder;
}
public static StringBuilder getCondition(String property) {
return new StringBuilder()
.append(ITEM).append(DOT).append(property);
}
}
然后就自定义mapper及sql注入器
public interface CustomMapper<T> extends BaseMapper<T> {
/**
* 批量插入
* @param collection 批量插入数据
* @return ignore
*/
int insertBatch(@Param("collection") Collection<T> collection);
/**
* 批量更新
* @param collection
* @return
*/
int updateBatchByIds(@Param("collection") Collection<T> collection);
}
这里sql注入器要判断下是继承了该类，才进行方法扩展
@ConditionalOnExpression("${mybatis-plus.custom-mapper.enabled:true}")
@Component
public class CustomSqlInject extends DefaultSqlInjector {
//初始化时候会加载
@Override
public List<AbstractMethod> getMethodList(Class<?> mapperClass) {
List<AbstractMethod> methodList = super.getMethodList(mapperClass);
//属于自己定义的mapper才添加方法
if (((ParameterizedTypeImpl) mapperClass.getGenericInterfaces()[0]).getRawType().equals(CustomMapper.class)) {
methodList.add(new InsertBatch());
methodList.add(new UpdateBatchByIds());
}
if (((ParameterizedTypeImpl) mapperClass.getGenericInterfaces()[0]).getRawType().equals(ComposeKeyMapper.class)) {
methodList.add(new SelectByComposeKeys());
methodList.add(new SelectIdsByComposeKeys());
methodList.add(new UpdateByComposeKeys());
methodList.add(new InsertBatch());
}
return methodList;
}
}
可以直接注入到spring里面，或者通过进行设置
GlobalConfigUtils.getGlobalConfig(sqlSessionFactory.getConfiguration()).setSqlInjector(xx)
测试一下，定义实体，下面的typeHandler可以去掉，
@TableName(
value = "demo"
)
@Data
@Accessors(chain = true)
public class Demo extends BaseEntity {
private static final long serialVersionUID = 1L;
@TableId("id")
private Long id;
@TableField("name")
private String name;
@TableField(
value = "age",
typeHandler = LongFormatAESEncryptHandler.class
)
private Long age;
@TableField(
value = "secret",
typeHandler = StringFormatAESEncryptHandler.class
)
private String secret;
@TableField(
value = "CREATED_ID",
fill = FieldFill.INSERT
)
private Long createdId;
@TableField(
value = "CREATED_BY",
fill = FieldFill.INSERT
)
private String createdBy;
@TableField(
value = "CREATION_DATE",
fill = FieldFill.INSERT
)
private Date creationDate;
@TableField(
value = "CREATED_BY_IP",
fill = FieldFill.INSERT
)
private String createdByIp;
@TableField(
value = "LAST_UPDATED_ID",
fill = FieldFill.UPDATE
)
private Long lastUpdatedId;
@TableField(
value = "LAST_UPDATED_BY",
fill = FieldFill.UPDATE
)
private String lastUpdatedBy;
@TableField(
value = "LAST_UPDATE_DATE",
fill = FieldFill.INSERT_UPDATE
)
private Date lastUpdateDate;
@TableField(
value = "LAST_UPDATED_BY_IP",
fill = FieldFill.UPDATE
)
private String lastUpdatedByIp;
}
继承自定义mapper
public interface TempMapper extends CustomMapper<Demo> {
}
controller了的两个方法，可以支持事务
@GetMapping("/testBatch")
@Transactional(rollbackFor = Exception.class)
public void testBatch() {
List<Demo> demos = new LinkedList<>();
for (int i = 0; i < 10; i++) {
Demo de = new Demo().setAge(Long.valueOf(i))
.setId(Long.valueOf(i + 1))
.setName("test" + i)
.setSecret(UUID.randomUUID().toString());
demos.add(de);
}
tempMapper.insertBatch(demos);
}
@GetMapping("/testBatch2")
@Transactional(rollbackFor = Exception.class)
public void testBatch2() {
List<Demo> demos = new LinkedList<>();
for (int i = 0; i < 5; i++) {
Demo de = new Demo().setAge(Long.valueOf(i))
.setId(Long.valueOf(i + 1))
.setName("test-change" + i)
.setSecret(UUID.randomUUID().toString());
demos.add(de);
}
tempMapper.updateBatchByIds(demos);
//int i=1/0;
}
对于自定sql注入，还可以抽取一些公用的方法进行添加，比如逻辑删除，版本号更新，进行联合主键的批量修改和查询，下面给出联合主键的处理方案
下面是构造根据wrapper和联合主键进行查询的，核心也是定义好sql，然后进行注入，但这里需要自定义一个注解来标识哪个是联合主键
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface ComposeKey {
}
public class SelectByComposeKeys extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.SELECT_BY_COMPOSEKEYS;
//select #{ew.sqlSelect} from table_name where (composekey1=xx and composekey2=xx) or (composekey1=xx1 and composekey2=xx1)
String sqlTemplate = sqlMethod.getSql();
String tableName = tableInfo.getTableName();
List<TableFieldInfo> composeKeys = tableInfo.getFieldList().stream().filter(e -> e.getField().isAnnotationPresent(ComposeKey.class))
.collect(Collectors.toList());
if(CollectionUtils.isEmpty(composeKeys)){
throw new ApiException("not composeKey found in class:"+modelClass.getName());
}
StringBuilder builder=new StringBuilder();
for (int i = 0; i < composeKeys.size(); i++) {
TableFieldInfo composeKey = composeKeys.get(i);
builder.append(composeKey.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + composeKey.getProperty()));
if(i!=composeKeys.size()-1){
builder.append(" ").append(AND).append(" ");
}
}
String finalSql = String.format(sqlTemplate, tableName, builder);
SqlSource sqlSource = languageDriver.createSqlSource(configuration, finalSql, modelClass);
return this.addSelectMappedStatementForTable(mapperClass,sqlMethod.getMethod(),sqlSource,tableInfo);
}
}
更新操作
public class UpdateByComposeKeys extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.UPDATE_BY_COMPOSEKEYS;
/**
* update table set <if test ="item.pro!=null">key1=#{item.pro}</if>, key2=#{item.pro2} where keycolom = %s
*/
StringBuilder withChevScript = new StringBuilder();
StringBuilder lastFiledScriptBuilder = new StringBuilder();
StringBuilder keyScriptBuilder = new StringBuilder();
StringBuilder placeHolder = new StringBuilder();
List<TableFieldInfo> fieldList = tableInfo.getFieldList();
for (int i = 0; i < fieldList.size(); i++) {
TableFieldInfo fieldInfo = fieldList.get(i);
Boolean isLast = (i == (fieldList.size() - 1));
if (fieldInfo.getField().isAnnotationPresent(ComposeKey.class)) {
keyScriptBuilder.append(" ").append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + fieldInfo.getProperty()))
.append(" ").append(AND);
placeHolder.append(fieldInfo.getColumn()).append(EQUALS).append(fieldInfo.getColumn()).append(COMMA);
continue;
}
//有插入默认填充器或者主键的不参与赋值
if (fieldInfo.isWithInsertFill() && !fieldInfo.isWithUpdateFill()) {
continue;
}
boolean change = false;
if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_NULL) && !fieldInfo.isWithUpdateFill()) {
SQLConditionWrapper.appendNotNull(withChevScript, fieldInfo.getProperty());
change = true;
}
if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_EMPTY) && !fieldInfo.isWithUpdateFill()) {
SQLConditionWrapper.appendNotEmpty(withChevScript, fieldInfo.getProperty());
change = true;
}
if (change) {
withChevScript.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString()));
withChevScript.append(COMMA).append("</if>");
if (isLast && lastFiledScriptBuilder.length() == 0) {
//如果没有其他字段替补，弄个占位的，不然会出现语法错误的情况
if (placeHolder.length() > 0) {
//删除多余的逗号
placeHolder.deleteCharAt(placeHolder.length() - 1);
withChevScript.append(placeHolder);
}
}
} else {
lastFiledScriptBuilder.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString())).append(COMMA);
}
}
if (placeHolder.length() == 0) {
throw new ApiException("not composeKey found in class:" + modelClass.getName());
}
//处理多余的逗号
if (!StringUtils.isBlank(lastFiledScriptBuilder) && !StringUtils.isBlank(withChevScript)) {
int leftChevIndex = withChevScript.lastIndexOf(LEFT_CHEV);
if (withChevScript.charAt(leftChevIndex - 1) != ',') {
withChevScript.replace(leftChevIndex, leftChevIndex + 1, ",<");
}
if (lastFiledScriptBuilder.lastIndexOf(COMMA) == lastFiledScriptBuilder.length() - 1) {
lastFiledScriptBuilder.deleteCharAt(lastFiledScriptBuilder.length() - 1);
}
}
if(!StringUtils.isBlank(keyScriptBuilder)){
int i = keyScriptBuilder.lastIndexOf(AND);
keyScriptBuilder.delete(i,i+AND.length());
}
withChevScript.append(lastFiledScriptBuilder);
// sql 模板占位符替换
String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), withChevScript, keyScriptBuilder);
// 模板写入
SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
return this.addUpdateMappedStatement(mapperClass, modelClass, sqlMethod.getMethod(), sqlSource);
}
}
public class SelectIdsByComposeKeys extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.SELECT_IDS_BY_COMPOSEKEYS;
//select composekeys from table_name where (composekey1=xx and composekey2=xx) or (composekey1=xx1 and composekey2=xx1)
String sqlTemplate = sqlMethod.getSql();
String tableName = tableInfo.getTableName();
List<TableFieldInfo> composeKeys = tableInfo.getFieldList().stream().filter(e -> e.getField().isAnnotationPresent(ComposeKey.class))
.collect(Collectors.toList());
if(CollectionUtils.isEmpty(composeKeys)){
throw new ApiException("not composeKey found in class:"+modelClass.getName());
}
StringBuilder builder=new StringBuilder();
StringBuilder select=new StringBuilder();
for (int i = 0; i < composeKeys.size(); i++) {
TableFieldInfo composeKey = composeKeys.get(i);
select.append(composeKey.getColumn());
builder.append(composeKey.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + composeKey.getProperty()));
if(i!=composeKeys.size()-1){
builder.append(" ").append(AND).append(" ");
select.append(COMMA);
}
}
String finalSql = String.format(sqlTemplate,select, tableName, builder);
SqlSource sqlSource = languageDriver.createSqlSource(configuration, finalSql, modelClass);
return this.addSelectMappedStatementForTable(mapperClass,sqlMethod.getMethod(),sqlSource,tableInfo);
}
}
public class DeleteByComposeKeys extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.DELETE_BY_COMPOSEKEYS;
//delete from table_name where (composekey1=xx and composekey2=xx) or (composekey1=xx1 and composekey2=xx1)
String sqlTemplate = sqlMethod.getSql();
String tableName = tableInfo.getTableName();
List<TableFieldInfo> composeKeys = tableInfo.getFieldList().stream().filter(e -> e.getField().isAnnotationPresent(ComposeKey.class))
.collect(Collectors.toList());
if(CollectionUtils.isEmpty(composeKeys)){
throw new ApiException("not composeKey found in class:"+modelClass.getName());
}
StringBuilder builder=new StringBuilder();
for (int i = 0; i < composeKeys.size(); i++) {
TableFieldInfo composeKey = composeKeys.get(i);
builder.append(composeKey.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + composeKey.getProperty()));
if(i!=composeKeys.size()-1){
builder.append(" ").append(AND).append(" ");
}
}
String finalSql = String.format(sqlTemplate, tableName, builder);
SqlSource sqlSource = languageDriver.createSqlSource(configuration, finalSql, modelClass);
return this.addDeleteMappedStatement(mapperClass, sqlMethod.getMethod(), sqlSource);
}
}
定义mappe类，这里对于原生的方法就不进行支持了
public interface ComposeKeyMapper<T> extends CustomMapper<T> {
/**
* @param params 查询的主键入参
* @param wrapper 查询的列会用到 ew.sqlSelect
* @return
*/
List<T> selectByComposeKeys(@Param("collection") Collection<T> params, @Param(Constants.WRAPPER) Wrapper<T> wrapper);
/**
* 批量更新
*
* @param params
*/
void updateByComposeKeys(@Param("collection") Collection<T> params);
/**
* 只查询主键
*
* @param params
* @return
*/
List<T> selectIdsByComposeKeys(@Param("collection") Collection<T> params);
/**
* 联合主键删除
* @param params
* @return
*/
int deleteByComposeKeys(@Param("collection")Collection<T> params);
/**
* 下面的方法不支持
* @param entity
* @return
*/
@Override
default int updateById(T entity) {
throw new UnsupportedOperationException();
}
@Override
default int updateBatchByIds(Collection<T> collection) {
throw new UnsupportedOperationException();
}
@Override
default T selectById(Serializable id) {
throw new UnsupportedOperationException();
}
@Override
default List<T> selectBatchIds(Collection<? extends Serializable> idList) {
throw new UnsupportedOperationException();
}
@Override
default int deleteBatchIds(Collection<? extends Serializable> idList){
throw new UnsupportedOperationException();
}
@Override
default int deleteById(Serializable id){
throw new UnsupportedOperationException();
}
}
可以看到查询是按照预期给出的，也支持wrapper形式的查询
要注意，xml文件里的优先级是比自定义注入的优先级高的，这里没给出单个update，单个查询，单个删除的方法，这些都可以根据自己业务需求弄一下，项目上没用到就不写了
对于sqlSession也可以自己做一些小优化
类型有reuse，编译一次可以继续服用，使用场景：执行同一个sql，参数值不同
默认的simple是每次都会编译一下
batch相当于一个会话里面执行多条sql
reuse示例
public static void executeReuse(Consumer<SqlSession> consumer) {
SqlSessionFactory factory = SpringContextHolder.getBean(SqlSessionFactory.class);
SqlSession sqlSession = factory.openSession(ExecutorType.REUSE, true);
try {
consumer.accept(sqlSession);
} finally {
sqlSession.close();
}
}
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