使用JPA支持多参数列表查询(参数可能为空)
作者：waani
这篇文章主要介绍了使用JPA支持多参数列表查询(参数可能为空),具有很好的参考价值,希望对大家有所帮助,如有错误或未考虑完全的地方,望不吝赐教
JPA支持多参数列表查询(参数可能为空)
1.JPA 支持写SQL语句查询
@Query(value = "select * from xxx ",nativeQuery = true)
2.JPA @Query的SQL语句
可以通过?1、?2这样获取查询方法里第一个参数、第二个参数，以此类推；或者是使用@Param("name")标识参数，然后使用 :name 获取。
3.mysql 的if函数，类似三目运算
if(sex=1, '男' , '女')
结合起来可以使用MySQL的if函数，来判断参数是否为空，为空时设置1=1，也就是查所有。
- 第一种方式：
?1获取参数
@Query(value = "select * from test_demo where if(?1 !='',name=?1,1=1) and if(?2 !='',info=?2,1=1) ",nativeQuery = true) List<TestDemo> find(String name, String info) ;
- 第二种方式：
:name获取参数
@Query(value = "select * from test_demo where if(:name !='',name= :name,1=1) and if(:info !='',info= :info,1=1) ",nativeQuery = true)
List<TestDemo> find2(@Param("name") String name, @Param("info") String info) ;
- 第三种方式：实体类获取参数
@Query(value = "select * from test_demo where if(:#{#testDemo.name} !='',name=:#{#testDemo.name},1=1) and if(:#{#testDemo.info} !='',info=:#{#testDemo.info},1=1) ",nativeQuery = true)
List<TestDemo> find3(@Param("testDemo")TestDemo testDemo) ;
这三种写法结果是一样的，主要逻辑就是使用MySQL的if函数，判断某个字段是否不为空，是的话就根据这个字段查询，否则就1=1（为了保证sql语句可以执行）。
同理可以拓展很多，包括模糊查询等，只要MySQL 支持的SQL语句就可以使用JPA来实现，同时JPA特有的分页也可以实现只需要传递Pageable对象并使用Page 接收数据即可。
@Query(value = "select * from test_demo where if(?1 !='',name=?1,1=1) and if(?2 !='',info=?2,1=1) ",nativeQuery = true) Page<TestDemo> find(String name, String info, Pageable pageable) ;
JPA动态查询 支持多字段模糊查询 排序
1、定义条件容器
import org.springframework.data.jpa.domain.Specification;
import org.springframework.util.CollectionUtils;
import javax.persistence.criteria.*;
import java.util.ArrayList;
import java.util.List;
/**
* 定义一个查询条件容器
* Created by gzs
*/
public class Criteria<T> implements Specification<T> {
private List<Criterion> criterions = new ArrayList<>();
private List<Criterion> orderCriterions = new ArrayList<>();
private List<Criterion> groupCriterions = new ArrayList<>();
@Override
public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query,
CriteriaBuilder builder) {
//处理查询条件
if (!criterions.isEmpty()) {
List<Predicate> predicates = new ArrayList<>();
for (Criterion c : criterions) {
Predicate predicate = c.toPredicate(root, query, builder);
predicates.add(predicate);
}
// 将所有条件用 and 联合起来
if (predicates.size() > 0) {
query.where(predicates.toArray(new Predicate[predicates.size()]));
}
// 将所有条件用 and 联合起来
/*if (predicates.size() > 0) {
return builder.and(predicates.toArray(new Predicate[predicates.size()]));
}*/
}
//处理排序
if (!orderCriterions.isEmpty()) {
List<Order> orders = new ArrayList<>();
for (Criterion c : orderCriterions) {
Order order = c.toOrder(root, query, builder);
orders.add(order);
}
if (!CollectionUtils.isEmpty(orders)) {
query.orderBy(orders);
}
}
//处理分组
if (!groupCriterions.isEmpty()) {
List<Expression> groups = new ArrayList<>();
for (Criterion c : groupCriterions) {
Expression group = c.toGroupBy(root, query, builder);
groups.add(group);
}
if (!CollectionUtils.isEmpty(groups)) {
Expression[] groupExpressions = (Expression[]) groups.toArray();
query.groupBy(groupExpressions);
}
}
return query.getRestriction();
//return builder.conjunction();
}
/**
* 增加简单条件表达式
*
* @Methods Name add
* @Create In 2018-10-15 By gzs
*/
public void add(Criterion criterion) {
if (criterion != null) {
criterions.add(criterion);
}
}
/**
* 增加排序表达式
*
* @Methods Name add
* @Create In 2018-11-15 By gzs
*/
public void addOrder(Criterion order) {
if (order != null) {
orderCriterions.add(order);
}
}
/**
* 增加排序表达式
*
* @Methods Name add
* @Create In 2018-11-15 By gzs
*/
public void addGroupBy(Criterion group) {
if (group != null) {
groupCriterions.add(group);
}
}
}2、条件表达式
import javax.persistence.criteria.*;
/**
* 创建条件表达式接口，模拟系统的条件查询
* Created by gzs
*/
public interface Criterion {
enum Operator {
EQ, NE, LIKE, GT, LT, GTE, LTE,
IS_NULL, IS_NOT_NULL,
AND, OR,
IS_MEMBER, IS_NOT_MEMBER,
DESC, ASC
}
Predicate toPredicate(Root<?> root, CriteriaQuery<?> query,
CriteriaBuilder builder);
Order toOrder(Root<?> root, CriteriaQuery<?> query,
CriteriaBuilder builder);
Expression toGroupBy(Root<?> root, CriteriaQuery<?> query,
CriteriaBuilder builder);
}3、实现逻辑条件表达式
import javax.persistence.criteria.*;
import java.util.ArrayList;
import java.util.List;
/**
* 逻辑条件表达式 用于复杂条件时使用，如单属性多对应值的OR查询等
*
* Created by gzs
*/
public class LogicalExpression implements Criterion {
/**
* 逻辑表达式中包含的表达式
*/
private Criterion[] criterion;
/**
* 计算符
*/
private Operator operator;
public LogicalExpression(Criterion[] criterions, Operator operator) {
this.criterion = criterions;
this.operator = operator;
}
@Override
public Predicate toPredicate(Root<?> root, CriteriaQuery<?> query,
CriteriaBuilder builder) {
List<Predicate> predicates = new ArrayList<>();
for (int i = 0; i < this.criterion.length; i++) {
Predicate predicate = this.criterion[i].toPredicate(root, query, builder);
predicates.add(predicate);
}
switch (operator) {
case OR:
return builder.or(predicates.toArray(new Predicate[predicates.size()]));
case AND:
return builder.and(predicates.toArray(new Predicate[predicates.size()]));
default:
return null;
}
}
@Override
public Order toOrder(Root<?> root, CriteriaQuery<?> query,
CriteriaBuilder builder) {
return null;
}
@Override
public Expression toGroupBy(Root<?> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
return null;
}
}4、实现简单条件表达式
import org.springframework.util.StringUtils;
import javax.persistence.criteria.*;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* 简单条件表达式
*
* Created by gzs
*/
public class SimpleExpression implements Criterion {
/**
* 属性名
*/
private String fieldName;
/**
* 对应值
*/
private Object value;
/**
* 计算符
*/
private Operator operator;
protected SimpleExpression(String fieldName, Operator operator) {
this.fieldName = fieldName;
this.operator = operator;
}
protected SimpleExpression(String fieldName, Object value, Operator operator) {
this.fieldName = fieldName;
this.value = value;
this.operator = operator;
}
@Override
@SuppressWarnings({"rawtypes", "unchecked"})
public Predicate toPredicate(Root<?> root, CriteriaQuery<?> query,
CriteriaBuilder builder) {
Path expression;
//此处是表关联数据，注意仅限一层关联，如user.address，
//查询user的address集合中，address的name为某个值
if (fieldName.contains(".")) {
String[] names = StringUtils.split(fieldName, ".");
//获取该属性的类型，Set？List？Map？
expression = root.get(names[0]);
Class clazz = expression.getJavaType();
if (clazz.equals(Set.class)) {
SetJoin setJoin = root.joinSet(names[0]);
expression = setJoin.get(names[1]);
} else if (clazz.equals(List.class)) {
ListJoin listJoin = root.joinList(names[0]);
expression = listJoin.get(names[1]);
} else if (clazz.equals(Map.class)) {
MapJoin mapJoin = root.joinMap(names[0]);
expression = mapJoin.get(names[1]);
} else {
//是many to one时
expression = expression.get(names[1]);
}
} else {
//单表查询
expression = root.get(fieldName);
}
switch (operator) {
case EQ:
return builder.equal(expression, value);
case NE:
return builder.notEqual(expression, value);
case LIKE:
return builder.like((Expression<String>) expression, "%" + value + "%");
case LT:
return builder.lessThan(expression, (Comparable) value);
case GT:
return builder.greaterThan(expression, (Comparable) value);
case LTE:
return builder.lessThanOrEqualTo(expression, (Comparable) value);
case GTE:
return builder.greaterThanOrEqualTo(expression, (Comparable) value);
case IS_NULL:
return builder.isNull(expression);
case IS_NOT_NULL:
return builder.isNotNull(expression);
case IS_MEMBER:
return builder.isMember(value, expression);
case IS_NOT_MEMBER:
return builder.isNotMember(value, expression);
default:
return null;
}
}
@Override
public Order toOrder(Root<?> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
return null;
}
@Override
public Expression toGroupBy(Root<?> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
return null;
}
}5、实现排序表达式
import org.springframework.util.StringUtils;
import javax.persistence.criteria.*;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* 逻辑条件表达式 用于复杂条件时使用，如单属性多对应值的OR查询等
*
* Created by gzs
*/
public class OrderExpression implements Criterion {
/**
* 计算符
*/
private Operator operator;
/**
* 属性名
*/
private String fieldName;
public OrderExpression(String fieldName, Operator operator) {
this.fieldName = fieldName;
this.operator = operator;
}
@Override
public Predicate toPredicate(Root<?> root, CriteriaQuery<?> query,
CriteriaBuilder builder) {
return null;
}
@Override
public Order toOrder(Root<?> root, CriteriaQuery<?> query,
CriteriaBuilder builder) {
Path expression;
//此处是表关联数据，注意仅限一层关联，如user.address，
//查询user的address集合中，address的name为某个值
if (fieldName.contains(".")) {
String[] names = StringUtils.split(fieldName, ".");
//获取该属性的类型，Set？List？Map？
expression = root.get(names[0]);
Class clazz = expression.getJavaType();
if (clazz.equals(Set.class)) {
SetJoin setJoin = root.joinSet(names[0]);
expression = setJoin.get(names[1]);
} else if (clazz.equals(List.class)) {
ListJoin listJoin = root.joinList(names[0]);
expression = listJoin.get(names[1]);
} else if (clazz.equals(Map.class)) {
MapJoin mapJoin = root.joinMap(names[0]);
expression = mapJoin.get(names[1]);
} else {
//是many to one时
expression = expression.get(names[1]);
}
} else {
//单表查询
expression = root.get(fieldName);
}
switch (operator) {
case DESC:
return builder.desc(expression);
default:
return builder.asc(expression);
}
}
@Override
public Expression toGroupBy(Root<?> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
return null;
}
}6、实现分组表达式 GroupByExpression
import org.springframework.util.StringUtils;
import javax.persistence.criteria.*;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* 分组条件表达式 用于复杂条件时使用等
*
* Created by gzs
*/
public class GroupByExpression implements Criterion {
/**
* 属性名
*/
private String fieldName;
public GroupByExpression(String fieldName) {
this.fieldName = fieldName;
}
@Override
public Predicate toPredicate(Root<?> root, CriteriaQuery<?> query,
CriteriaBuilder builder) {
return null;
}
@Override
public Order toOrder(Root<?> root, CriteriaQuery<?> query,
CriteriaBuilder builder) {
return null;
}
@Override
public Expression toGroupBy(Root<?> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
Path expression;
//此处是表关联数据，注意仅限一层关联，如user.address，
//查询user的address集合中，address的name为某个值
if (fieldName.contains(".")) {
String[] names = StringUtils.split(fieldName, ".");
//获取该属性的类型，Set？List？Map？
expression = root.get(names[0]);
Class clazz = expression.getJavaType();
if (clazz.equals(Set.class)) {
SetJoin setJoin = root.joinSet(names[0]);
expression = setJoin.get(names[1]);
} else if (clazz.equals(List.class)) {
ListJoin listJoin = root.joinList(names[0]);
expression = listJoin.get(names[1]);
} else if (clazz.equals(Map.class)) {
MapJoin mapJoin = root.joinMap(names[0]);
expression = mapJoin.get(names[1]);
} else {
//是many to one时
expression = expression.get(names[1]);
}
} else {
//单表查询
expression = root.get(fieldName);
}
return expression;
}
}import org.springframework.util.StringUtils;
import java.util.Collection;
/**
* 条件构造器
* 用于创建条件表达式
*
* Created by gzs
*/
public class Restrictions {
/**
* 等于
*/
public static SimpleExpression eq(String fieldName, Object value, boolean ignoreNull) {
if (ignoreNull && StringUtils.isEmpty(value)) {
return null;
}
return new SimpleExpression(fieldName, value, Criterion.Operator.EQ);
}
/**
* 为null
*/
public static SimpleExpression isNull(String fieldName) {
return new SimpleExpression(fieldName, Criterion.Operator.IS_NULL);
}
/**
* 不为null
*/
public static SimpleExpression isNotNull(String fieldName) {
return new SimpleExpression(fieldName, Criterion.Operator.IS_NOT_NULL);
}
/**
* 集合包含某个元素
*/
public static SimpleExpression hasMember(String fieldName, Object value, boolean ignoreNull) {
if (ignoreNull && StringUtils.isEmpty(value)) {
return null;
}
return new SimpleExpression(fieldName, value, Criterion.Operator.IS_MEMBER);
}
/**
* 不等于
*/
public static SimpleExpression ne(String fieldName, Object value, boolean ignoreNull) {
if (ignoreNull && StringUtils.isEmpty(value)) {
return null;
}
return new SimpleExpression(fieldName, value, Criterion.Operator.NE);
}
/**
* 模糊匹配
*/
public static SimpleExpression like(String fieldName, String value, boolean ignoreNull) {
if (ignoreNull && StringUtils.isEmpty(value)) {
return null;
}
return new SimpleExpression(fieldName, value, Criterion.Operator.LIKE);
}
/**
*/
// public static SimpleExpression like(String fieldName, String value,
// MatchMode matchMode, boolean ignoreNull) {
// if (StringUtils.isEmpty(value)) return null;
// return null;
// }
/**
* 大于
*/
public static SimpleExpression gt(String fieldName, Object value, boolean ignoreNull) {
if (ignoreNull && StringUtils.isEmpty(value)) {
return null;
}
return new SimpleExpression(fieldName, value, Criterion.Operator.GT);
}
/**
* 小于
*/
public static SimpleExpression lt(String fieldName, Object value, boolean ignoreNull) {
if (ignoreNull && StringUtils.isEmpty(value)) {
return null;
}
return new SimpleExpression(fieldName, value, Criterion.Operator.LT);
}
/**
* 小于等于
*/
public static SimpleExpression lte(String fieldName, Object value, boolean ignoreNull) {
if (ignoreNull && StringUtils.isEmpty(value)) {
return null;
}
return new SimpleExpression(fieldName, value, Criterion.Operator.LTE);
}
/**
* 大于等于
*/
public static SimpleExpression gte(String fieldName, Object value, boolean ignoreNull) {
if (ignoreNull && StringUtils.isEmpty(value)) {
return null;
}
return new SimpleExpression(fieldName, value, Criterion.Operator.GTE);
}
/**
* 降序
*/
public static OrderExpression desc(String fieldName) {
/*if (StringUtils.isEmpty(fieldName)) {
return null;
}*/
return new OrderExpression(fieldName, Criterion.Operator.DESC);
}
/**
* 升序
*/
public static OrderExpression asc(String fieldName) {
/*if (StringUtils.isEmpty(fieldName)) {
return null;
}*/
return new OrderExpression(fieldName, Criterion.Operator.ASC);
}
/**
* 并且
*/
public static LogicalExpression and(Criterion... criterions) {
return new LogicalExpression(criterions, Criterion.Operator.AND);
}
/**
* 或者
*/
public static LogicalExpression or(Criterion... criterions) {
return new LogicalExpression(criterions, Criterion.Operator.OR);
}
/**
* 包含于
*/
@SuppressWarnings("rawtypes")
public static LogicalExpression in(String fieldName, Collection value, boolean ignoreNull) {
if (ignoreNull && (value == null || value.isEmpty())) {
return null;
}
SimpleExpression[] ses = new SimpleExpression[value.size()];
int i = 0;
for (Object obj : value) {
ses[i] = new SimpleExpression(fieldName, obj, Criterion.Operator.EQ);
i++;
}
return new LogicalExpression(ses, Criterion.Operator.OR);
}
/**
* 集合包含某几个元素，譬如可以查询User类中Set<String> set包含"ABC","bcd"的User集合，
* 或者查询User中Set<Address>的Address的name为"北京"的所有User集合
* 集合可以为基本类型或者JavaBean，可以是one to many或者是@ElementCollection
* @param fieldName
* 列名
* @param value
* 集合
* @return
* expresssion
*/
public static LogicalExpression hasMembers(String fieldName, Object... value) {
SimpleExpression[] ses = new SimpleExpression[value.length];
int i = 0;
//集合中对象是基本类型，如Set<Long>，List<String>
Criterion.Operator operator = Criterion.Operator.IS_MEMBER;
//集合中对象是JavaBean
if (fieldName.contains(".")) {
operator = Criterion.Operator.EQ;
}
for (Object obj : value) {
ses[i] = new SimpleExpression(fieldName, obj, operator);
i++;
}
return new LogicalExpression(ses, Criterion.Operator.OR);
}
/**
* 分组
*/
public static GroupByExpression groupBy(String fieldName) {
if (StringUtils.isEmpty(fieldName)) {
return null;
}
return new GroupByExpression(fieldName);
}
}7、见证奇迹的时刻来了demo
if (StringUtils.isNotBlank(teacher.getContactName())) {
//动态查询
Criteria<Teacher> criteria = new Criteria<>();
final LogicalExpression or = Restrictions.or(
Restrictions.like("code", teacher.getContactName(), true),
Restrictions.like("contactName", teacher.getContactName(), true),
Restrictions.like("mobile", teacher.getContactName(), true));
criteria.add(or);
criteria.add(Restrictions.eq("groupMerchantId", teacher.getGroupMerchantId(), true));
criteria.add(Restrictions.eq("merchantId", teacher.getMerchantId(), true));
criteria.add(Restrictions.eq("campusId", teacher.getCampusId(), true));
criteria.addOrder(Restrictions.desc("gmtModified"));
Pageable pageable = new PageRequest(pageNo - 1, pageSize); //页码：前端从1开始，jpa从0开始，做个转换
org.springframework.data.domain.Page<Teacher> cmsUsers = teacherRepository.findAll(criteria, pageable);总结
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。