1. JPQL基于@Query注解的查询
1.1. JPQL是通过Hibernate的HQL演变过来的, 它和HQL语法及其相似。
1.2. 因为Hibernate的HQL语言是用于面向对象实现查询功能的, 然而在插入操作中是不会牵涉任何查询动作的, 所以HQL不能用于insert语句的插入操作, 而select、update、delete语句都可以有可能的查询实现。比如: update语句: update 对象名 set … where …; delete语句: delete from 对象名 where …。所以, update与delete牵涉到where的查询筛选过程, 这个过程是需要采用HQL来实现的, 然而insert永远牵涉不到查询筛选过程, 所以Hibernate没有对插入做insert实现。
2. JPQL查询更新删除例子
2.1. 创建一个名为spring-data-jpa-jpql的Java项目, 同时添加相关jar包, 并添加JUnit能力。
2.2. 新建User.java
package com.bjbs.pojo;
import java.io.Serializable;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import org.springframework.format.annotation.DateTimeFormat;
@Entity // 指定该类是实体类
@Table(name = "user") // 指定数据库表名(表名和实体类对应)
public class User implements Serializable {
private static final long serialVersionUID = 1L;
@Id // 指定为主键
@GeneratedValue(strategy = GenerationType.IDENTITY) // 指定主键生成策略
@Column(name = "id") // 指定表中列名(列名和属性名对应)
private Integer id;
@Column(name = "name")
private String name;
@Column(name = "sex")
private String sex;
@Column(name = "birthday")
@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private Date birthday;
@Column(name = "address")
private String address;
public User() {
}
public User(String name, String sex, Date birthday, String address) {
this.name = name;
this.sex = sex;
this.birthday = birthday;
this.address = address;
}
public User(Integer id, String name, String sex, Date birthday, String address) {
this.id = id;
this.name = name;
this.sex = sex;
this.birthday = birthday;
this.address = address;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", sex=" + sex + ", birthday=" + birthday + ", address=" + address
+ "]";
}
}
2.3. 新建UserRepository.java, 实现Repository
package com.bjbs.dao;
import java.util.List;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.Repository;
import com.bjbs.pojo.User;
/**
* 参数一T: 当前需要映射的实体; 参数二 T: 当前映射的实体中的id的类型
*/
public interface UserRepository extends Repository<User, Integer> {
@Query(value="from User where name = ?")
public User queryUserByName(String name);
@Query("from User where name like ?")
public List<User> queryUserByNameLike(String name);
@Query("from User where name = ? and sex >= ?")
public User queryUserByNameAndSex(String name, String sex);
@Query(value="update User set sex = ? where id = ?")
@Modifying //@Modifying当前语句是一个更新语句
public Integer updateUserSexById(String sex, Integer id);
@Query(value="delete User where id = ?")
@Modifying
public Integer deleteUserById(Integer id);
}
2.4. JPQL语句中使用的是实体类名, 不是表名
2.5. 新建UserService.java
package com.bjbs.service;
import java.util.List;
import com.bjbs.pojo.User;
public interface UserService {
public User queryUserByName(String name);
public List<User> queryUserByNameLike(String name);
public User queryUserByNameAndSex(String name, String sex);
public Integer updateUserSexById(String sex, Integer id);
public Integer deleteUserById(Integer id);
}
2.6. 新建UserServiceImpl.java
package com.bjbs.service.impl;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.bjbs.dao.UserRepository;
import com.bjbs.pojo.User;
import com.bjbs.service.UserService;
@Service
@Transactional
public class UserServiceImpl implements UserService {
@Autowired
private UserRepository userRepository;
@Override
public User queryUserByName(String name) {
return userRepository.queryUserByName(name);
}
@Override
public List<User> queryUserByNameLike(String name) {
return userRepository.queryUserByNameLike(name);
}
@Override
public User queryUserByNameAndSex(String name, String sex) {
return userRepository.queryUserByNameAndSex(name, sex);
}
@Override
public Integer updateUserSexById(String sex, Integer id) {
return userRepository.updateUserSexById(sex, id);
}
@Override
public Integer deleteUserById(Integer id) {
return userRepository.deleteUserById(id);
}
}
2.7. 新建TestUserRepository.java
package com.bjbs.test;
import java.util.List;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import com.bjbs.pojo.User;
import com.bjbs.service.UserService;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class TestUserRepository {
@Autowired
private UserService userService;
/**
* 查询名字叫'曹操'的用户
*/
@Test
public void queryUserByName() {
User userDb = userService.queryUserByName("曹操");
System.out.println(userDb);
}
/**
* 查询姓'李'的所有用户
*/
@Test
public void queryUserByNameLike() {
List<User> list = userService.queryUserByNameLike("李%");
for (User user : list) {
System.out.println(user);
}
}
/**
* 查询名字叫'曹操'并且性别为'男'的用户
*/
@Test
public void queryUserByNameAndSex() {
User userDb = userService.queryUserByNameAndSex("曹操", "男");
System.out.println(userDb);
}
/**
* 通过id更新用户性别
*/
@Test
public void updateUserSexById() {
int result = userService.updateUserSexById("女", 51);
System.out.println("result = " + result);
}
/**
* 通过id删除用户
*/
@Test
public void deleteUserById() {
int result = userService.deleteUserById(63);
System.out.println("result = " + result);
}
}
2.8. 在src下新建application.properties
spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://192.168.25.138:3306/StudyMybatis?useSSL=true&useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=lyw123456
2.9. 在src下新建applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:jpa="http://www.springframework.org/schema/data/jpa"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
<!-- 配置读取properties文件的工具类 -->
<context:property-placeholder location="classpath:application.properties" />
<!-- 配置c3p0数据库连接池 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="jdbcUrl" value="${spring.datasource.url}" />
<property name="driverClass" value="${spring.datasource.driverClassName}" />
<property name="user" value="${spring.datasource.username}" />
<property name="password" value="${spring.datasource.password}" />
</bean>
<!-- Spring整合JPA 配置EntityManagerFactory -->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<!-- hibernate相关的属性的注入 -->
<!-- 配置数据库类型 -->
<property name="database" value="MYSQL" />
<!-- 正向工程 自动创建表 -->
<!-- <property name="generateDdl" value="true" /> -->
<!-- 显示执行的SQL -->
<property name="showSql" value="true" />
</bean>
</property>
<!-- 扫描实体的包 -->
<property name="packagesToScan">
<list>
<value>com.bjbs.pojo</value>
</list>
</property>
</bean>
<!-- 配置Hibernate的事务管理器 -->
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<!-- 配置开启注解事务处理 -->
<tx:annotation-driven transaction-manager="transactionManager" />
<!-- 配置springIOC的注解扫描 -->
<context:component-scan base-package="com.bjbs.service" />
<!-- Spring Data JPA 的配置 -->
<!-- base-package: 扫描dao接口所在的包 -->
<jpa:repositories base-package="com.bjbs.dao" />
</beans>
2.10. 数据库user表
2.11. 查询名字叫'曹操'的用户
2.12. 查询姓'李'的所有用户
2.13. 查询名字叫'曹操'并且性别为'男'的用户
2.14. 通过id更新用户性别
2.15. 通过id删除用户