MybatisPlus,无XML分分钟实现CRUD操作
作者：cjx不吃包子
这篇文章主要介绍了MybatisPlus,无XML分分钟实现CRUD操作，具有很好的参考价值，希望对大家有所帮助。一起跟随小编过来看看吧
不讲太多理论知识，官网都有，直接上手。
1.测试表
DROP TABLE IF EXISTS `user`; CREATE TABLE `user` ( `id` bigint(20) UNSIGNED NOT NULL, `name` varchar(128) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用户名', `password` varchar(18) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '密码', `age` int(4) DEFAULT NULL COMMENT '年龄', `create_time` datetime(0) DEFAULT NULL COMMENT '创建时间', `update_time` datetime(0) DEFAULT NULL COMMENT '更新时间', PRIMARY KEY (`id`) USING BTREE ) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
引入依赖
<!--mybatis-plus核心包--> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.0.5</version> </dependency> <!--mysql--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency>
配置文件，这里我用的是boot项目
spring: datasource: username: cjx password: cjx19950616 url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai driver-class-name: com.mysql.cj.jdbc.Driver mybatis-plus: mapper-locations: classpath:/mapper/*.xml #configuration: #map-underscore-to-camel-case: true
其实简单的crud甚至不需要mybatis-plus的配置，我这里没删除，本文也并没有用到配置文件。
实体类
public class User{
private Long id;
private String name;
private String password;
private int age;
private Date createTime;
private Date updateTime;
...
getter && setter
...
toString()
}
分页插件
@Configuration
public class MyBtaisPlusConfig {
/**
* 分页插件
* @return
*/
@Bean
public PaginationInterceptor paginationInterceptor() {
System.out.println("加载分页插件");
return new PaginationInterceptor();
}
}
编写一个我们的接口
@Component
public interface UserDao extends BaseMapper<User> {
Integer deleteById(Long id);
}
接下来就可以愉快的测试了，在我们的测试类里先注入dao
@Autowired
private UserDao userMapper;
新增测试
/**
* 新增
*/
@Test
void save(){
User u = new User();
u.setAge(100);
u.setName("测试数据3");
u.setPassword("cjx1111");
u.setAge(25);
int row = userMapper.insert(u);
System.out.println(row);
}
是不是很简单？只需要这样就可以完成新增了，既然有单个插入，那少不了也有批量插入
批量新增测试
/**
* 批量插入
*/
@Test
void save(){
List<User> us = new LinkedList<User>();
for (int i = 0;i < 50;i++){
User u = new User();
u.setName("测试数据"+i);
u.setAge((int)(Math.random()*90+10));
u.setPassword("mima"+i);
us.add(u);
}
userService.saveBatch(us);
}
其中用到了userService，我这里贴一下代码，需要我们接口继承Iservice,实现类继承ServiceImple<M,T>,这样就可以直接调用mybatis-plus为我们提供的现成方法了。
public interface IUserService extends IService<User> {
}
实现类
@Service public class UserServiceImpl extends ServiceImpl<UserDao, User>implements IUserService {
}
修改
/**
* 修改
*/
@Test
void updateById(){
User u = new User();
//修改name
u.setId(1L);
u.setName("修改下数据--");
u.setPassword("123");
u.setAge(99);
int row = userMapper.updateById(u);
System.out.println(row);
}
/**
* 通过id查询
*/
@Test
void selectById(){
//1.通过id来查询
User u = userMapper.selectById(1l);
System.out.println(u);
}
mybatis-plus有个特别好用的就是它的条件构造器，可以帮助我们构造常用的sql，具体用法我会贴在文章最后面。
/**
* 通过条件构造器查询
*/
@Test
void selectByWrapper(){
//3.通过条件构造器wrapper
QueryWrapper qw = new QueryWrapper();
qw.like("name","测试");
qw.lt("age",50);//小于
qw.gt("age",15);//大于
List<User> us = userMapper.selectList(qw);
us.stream().forEach(System.out::println);
}
既然有查询，自然少不了我们最关心的分页
/**
* 通过条件构造器和page分页查询
*/
@Test
void selectByWrapperAndPage(){
//4.通过条件构造器wrapper和Page分页查询
QueryWrapper qw = new QueryWrapper();
qw.like("name","测试");
qw.lt("age",50);//小于
qw.gt("age",15);//大于
qw.orderByDesc("age");
IPage<User> result = userMapper.selectPage(new Page<>(2,10),qw);
/**
* 查询总记录数
*/
@Test
void selectCount(){
//5.通过条件查询总条数
QueryWrapper qw = new QueryWrapper();
qw.like("name","测试");
qw.lt("age",50);//小于
qw.gt("age",15);//大于
qw.orderByDesc("age");
int count = userMapper.selectCount(qw);
System.out.println(count);
}
删除
/**
* 通过id删除
*/
@Test
void delete(){
int row = userMapper.deleteById(27l);
System.out.println(row);
}
/**
* 通过id批量删除
*/
@Test
void deleteBatch(){
int row = userMapper.deleteBatchIds(Arrays.asList(67l,44l,37l,220l));
System.out.println(row);
}
/**
* 通过条件删除
*/
@Test
void deleteByWrapper(){
QueryWrapper<User> qw = new QueryWrapper<>();
qw.gt("age",70);
//先来看看有多少数据
int row = userMapper.selectCount(qw);
System.out.println(row);
//删除
int deleteRow = userMapper.delete(qw);
System.out.println(deleteRow);
}
今天就到这，后续会给大家分享下mybatis-plus提供的sql性能执行分析插件、乐观锁插件以及字段的自动填充。
补充知识：Mybatis-plus 自动生成代码后xml文件和mapper映射不到的原因
报了如下错误
找了很久都没找到原因
2020-06-08 18:48:12 |ERROR |http-nio-8130-exec-3 |GlobalExceptionHandler.java:25 |service.base.handler.GlobalExceptionHandler |org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): service.used.mapper.ClassifyMapper.selectNestedListByParentId at org.apache.ibatis.binding.MapperMethod$SqlCommand.<init>(MapperMethod.java:235) at com.baomidou.mybatisplus.core.override.MybatisMapperMethod.<init>(MybatisMapperMethod.java:50) at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.lambda$cachedMapperMethod$0(MybatisMapperProxy.java:101) at java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1660) at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.cachedMapperMethod(MybatisMapperProxy.java:100) at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.invoke(MybatisMapperProxy.java:95) at com.sun.proxy.$Proxy98.selectNestedListByParentId(Unknown Source) at xyz.oneadd.platform.service.used.service.impl.ClassifyServiceImpl.nestedList(ClassifyServiceImpl.java:25) at xyz.oneadd.platform.service.used.service.impl.ClassifyServiceImpl$$FastClassBySpringCGLIB$$85da3417.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:685) at xyz.oneadd.platform.service.used.service.impl.ClassifyServiceImpl$$EnhancerBySpringCGLIB$$3b7bb86f.nestedList(<generated>) at xyz.oneadd.platform.service.used.controller.api.ApiClassifyController.classifyList(ApiClassifyController.java:34) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:888) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1591) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748)
原因是pom中没有添加bulid依赖
添加依赖后解决问题
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
</build>
以上这篇MybatisPlus,无XML分分钟实现CRUD操作就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持脚本之家。