1. JPQL基于@Query注解的查詢

1.1. JPQL是通過Hibernate的HQL演變過來的, 它和HQL語法及其相似。

1.2. 因為Hibernate的HQL語言是用于面向對象實現查詢功能的, 然而在插入操作中是不會牽涉任何查詢動作的, 所以HQL不能用于insert語句的插入操作, 而select、update、delete語句都可以有可能的查詢實現。比如: update語句: update 對象名 set … where …; delete語句: delete from 對象名 where …。所以, update與delete牽涉到where的查詢篩選過程, 這個過程是需要采用HQL來實現的, 然而insert永遠牽涉不到查詢篩選過程, 所以Hibernate沒有對插入做insert實現。

2. JPQL查詢更新刪除例子

2.1. 創建一個名為spring-data-jpa-jpql的Java項目, 同時添加相關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 // 指定該類是實體類 @Table(name = "user") // 指定數據庫表名(表名和實體類對應) public class User implements Serializable {private static final long serialVersionUID = 1L;@Id // 指定為主鍵@GeneratedValue(strategy = GenerationType.IDENTITY) // 指定主鍵生成策略@Column(name = "id") // 指定表中列名(列名和屬性名對應)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;}@Overridepublic String toString() {return "User [id=" + id + ", name=" + name + ", sex=" + sex + ", birthday=" + birthday + ", address=" + address+ "]";} }

2.3. 新建UserRepository.java, 實現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;/*** 參數一T: 當前需要映射的實體; 參數二 T: 當前映射的實體中的id的類型*/ 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當前語句是一個更新語句public Integer updateUserSexById(String sex, Integer id);@Query(value="delete User where id = ?")@Modifying public Integer deleteUserById(Integer id); }

2.4. JPQL語句中使用的是實體類名, 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 {@Autowiredprivate UserRepository userRepository;@Overridepublic User queryUserByName(String name) {return userRepository.queryUserByName(name);}@Overridepublic List<User> queryUserByNameLike(String name) {return userRepository.queryUserByNameLike(name);}@Overridepublic User queryUserByNameAndSex(String name, String sex) {return userRepository.queryUserByNameAndSex(name, sex);}@Overridepublic Integer updateUserSexById(String sex, Integer id) {return userRepository.updateUserSexById(sex, id);}@Overridepublic 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 {@Autowiredprivate UserService userService;/*** 查詢名字叫'曹操'的用戶*/@Testpublic void queryUserByName() {User userDb = userService.queryUserByName("曹操");System.out.println(userDb);}/*** 查詢姓'李'的所有用戶*/@Testpublic void queryUserByNameLike() {List<User> list = userService.queryUserByNameLike("李%");for (User user : list) {System.out.println(user);}}/*** 查詢名字叫'曹操'并且性別為'男'的用戶*/@Testpublic void queryUserByNameAndSex() {User userDb = userService.queryUserByNameAndSex("曹操", "男");System.out.println(userDb);}/*** 通過id更新用戶性別*/@Testpublic void updateUserSexById() {int result = userService.updateUserSexById("女", 51);System.out.println("result = " + result);}/*** 通過id刪除用戶*/@Testpublic 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.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsdhttp://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"><!-- 配置讀取properties文件的工具類 --><context:property-placeholder location="classpath:application.properties" /><!-- 配置c3p0數據庫連接池 --><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相關的屬性的注入 --><!-- 配置數據庫類型 --><property name="database" value="MYSQL" /><!-- 正向工程 自動創建表 --><!-- <property name="generateDdl" value="true" /> --><!-- 顯示執行的SQL --><property name="showSql" value="true" /></bean></property><!-- 掃描實體的包 --><property name="packagesToScan"><list><value>com.bjbs.pojo</value></list></property></bean><!-- 配置Hibernate的事務管理器 --><bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"><property name="entityManagerFactory" ref="entityManagerFactory" /></bean><!-- 配置開啟注解事務處理 --><tx:annotation-driven transaction-manager="transactionManager" /><!-- 配置springIOC的注解掃描 --><context:component-scan base-package="com.bjbs.service" /><!-- Spring Data JPA 的配置 --><!-- base-package: 掃描dao接口所在的包 --><jpa:repositories base-package="com.bjbs.dao" /> </beans>

2.10. 數據庫user表

2.11. 查詢名字叫'曹操'的用戶?

2.12. 查詢姓'李'的所有用戶?

2.13. 查詢名字叫'曹操'并且性別為'男'的用戶?

2.14. 通過id更新用戶性別?

2.15. 通過id刪除用戶?

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