SpringDataJPA详解

约定不等于承诺〃 2023-10-13 12:49 13阅读 0赞

#### 一、 创建SpringDataJPA项目 ####

1.  ##### 导入依赖 #####
    
        <groupId>com.yy</groupId>
          <artifactId>SpringDataJpaDemo02</artifactId>
          <version>1.0-SNAPSHOT</version>
          <packaging>jar</packaging>
        
          <name>SpringDataJpaDemo02</name>
          <url>http://maven.apache.org</url>
        
          <properties>
            <spring.version>4.2.4.RELEASE</spring.version>
            <hibernate.version>5.0.7.Final</hibernate.version>
            <slf4j.version>1.6.6</slf4j.version>
            <log4j.version>1.2.12</log4j.version>
            <c3p0.version>0.9.1.2</c3p0.version>
            <mysql.version>8.0.31</mysql.version>
          </properties>
        
          <dependencies>
            <dependency>
              <groupId>org.projectlombok</groupId>
              <artifactId>lombok</artifactId>
              <version>1.18.26</version>
            </dependency>
            
            <dependency>
              <groupId>junit</groupId>
              <artifactId>junit</artifactId>
              <version>4.9</version>
              <scope>test</scope>
            </dependency>
        
            
            <dependency>
              <groupId>org.aspectj</groupId>
              <artifactId>aspectjweaver</artifactId>
              <version>1.6.8</version>
            </dependency>
        
            <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-aop</artifactId>
              <version>${spring.version}</version>
            </dependency>
        
            <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-context</artifactId>
              <version>${spring.version}</version>
            </dependency>
        
            <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-context-support</artifactId>
              <version>${spring.version}</version>
            </dependency>
        
            <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-orm</artifactId>
              <version>${spring.version}</version>
            </dependency>
        
            <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-beans</artifactId>
              <version>${spring.version}</version>
            </dependency>
        
            <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-core</artifactId>
              <version>${spring.version}</version>
            </dependency>
        
            
        
            
            <dependency>
              <groupId>org.hibernate</groupId>
              <artifactId>hibernate-core</artifactId>
              <version>${hibernate.version}</version>
            </dependency>
            <dependency>
              <groupId>org.hibernate</groupId>
              <artifactId>hibernate-entitymanager</artifactId>
              <version>${hibernate.version}</version>
            </dependency>
            <dependency>
              <groupId>org.hibernate</groupId>
              <artifactId>hibernate-validator</artifactId>
              <version>5.2.1.Final</version>
            </dependency>
            
        
            
            <dependency>
              <groupId>c3p0</groupId>
              <artifactId>c3p0</artifactId>
              <version>${c3p0.version}</version>
            </dependency>
            
        
            
            <dependency>
              <groupId>log4j</groupId>
              <artifactId>log4j</artifactId>
              <version>${log4j.version}</version>
            </dependency>
        
            <dependency>
              <groupId>org.slf4j</groupId>
              <artifactId>slf4j-api</artifactId>
              <version>${slf4j.version}</version>
            </dependency>
        
            <dependency>
              <groupId>org.slf4j</groupId>
              <artifactId>slf4j-log4j12</artifactId>
              <version>${slf4j.version}</version>
            </dependency>
            
        
        
            <dependency>
              <groupId>mysql</groupId>
              <artifactId>mysql-connector-java</artifactId>
              <version>${mysql.version}</version>
            </dependency>
        
            <dependency>
              <groupId>org.springframework.data</groupId>
              <artifactId>spring-data-jpa</artifactId>
              <version>1.9.0.RELEASE</version>
            </dependency>
        
            <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-test</artifactId>
              <version>4.2.4.RELEASE</version>
            </dependency>
        
            
            <dependency>
              <groupId>javax.el</groupId>
              <artifactId>javax.el-api</artifactId>
              <version>2.2.4</version>
            </dependency>
        
            <dependency>
              <groupId>org.glassfish.web</groupId>
              <artifactId>javax.el</artifactId>
              <version>2.2.4</version>
            </dependency>
            
          </dependencies>
2.  ##### 创建配置文件beans.xml #####

配置数据源  
配置实体管理器工厂(注入数据源、配置实体包扫描、配置Hibernate供应商信息)  
配置事务管理器(注入实体管理器工厂)  
配置JPA数据增强(配置dao层包扫描、配置实体管理器、配置事务管理器)

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
           xmlns:context="http://www.springframework.org/schema/context"
           xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:tx="http://www.springframework.org/schema/tx"
           xmlns:jpa="http://www.springframework.org/schema/data/jpa" xmlns:task="http://www.springframework.org/schema/task"
           xsi:schemaLocation="
    		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
    		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
    		http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd
    		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
    		http://www.springframework.org/schema/data/jpa
    		http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">
    
        
        <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
            <property name="driverClass" value="com.mysql.cj.jdbc.Driver" />
            <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/jpa" />
            <property name="user" value="root" />
            <property name="password" value="123sa" />
        </bean>
    
        
        <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
            <property name="dataSource" ref="dataSource" />
            <property name="packagesToScan" value="com.yy.entity" />
            <property name="persistenceProvider">
                <bean class="org.hibernate.jpa.HibernatePersistenceProvider" />
            </property>
            
            <property name="jpaVendorAdapter">
                <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                    <property name="generateDdl" value="false" />
                    <property name="database" value="MYSQL" />
                    <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect" />
                    <property name="showSql" value="true" />
                </bean>
            </property>
            <property name="jpaDialect">
                <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
            </property>
            
            <property name="jpaProperties">
                <props>
                    <prop key="hibernate.hbm2ddl.auto">update</prop>
                </props>
            </property>
        </bean>
    
    
        
        
        <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
            <property name="entityManagerFactory" ref="entityManagerFactory" />
        </bean>
    
        
        <jpa:repositories base-package="com.yy.dao"
                          transaction-manager-ref="transactionManager"
                          entity-manager-factory-ref="entityManagerFactory"></jpa:repositories>
    
        
        <tx:advice id="txAdvice" transaction-manager="transactionManager">
            <tx:attributes>
                <tx:method name="save*" propagation="REQUIRED"/>
                <tx:method name="insert*" propagation="REQUIRED"/>
                <tx:method name="update*" propagation="REQUIRED"/>
                <tx:method name="delete*" propagation="REQUIRED"/>
                <tx:method name="get*" read-only="true"/>
                <tx:method name="find*" read-only="true"/>
                <tx:method name="*" propagation="REQUIRED"/>
            </tx:attributes>
        </tx:advice>
    
        
    
    
    
    
    
    
    
        
    
    </beans>

##### 3.数据库，实体类的创建 #####

package com.yy.entity;
    import lombok.AllArgsConstructor;
    import lombok.Data;
    import lombok.NoArgsConstructor;
    
    import javax.persistence.*;
    
    /**
     * @Author 杨 
     * @CreateDate 2023-07-04 11:20
     **/
    @Data
    @NoArgsConstructor
    @AllArgsConstructor
    @Entity
    @Table(name = "t_users")
    public class User {
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private int id;
        private String username;
        private String pwd;
        private int age;

Dao层继承 JpaRepository<User,Integer>, JpaSpecificationExecutor<User>

public interface UserDao extends JpaRepository<User,Integer>, JpaSpecificationExecutor<User>

##### 4.测试 #####

在测试类上标注读取配置文件

@RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(locations="classpath:spring.xml")
    
    
    @Autowired
    依赖注入UserDao

#### 二、基本增删改查 ####

*  添加

@Test
        public void add(){
            User user = new User("阿华", "1111", 40);
            userDao.save(user);
        }

*  修改

@Test
        public void upd(){
            User user = new User(6,"华仔", "666", 40);
            userDao.save(user);
        }

*  删除

@Test
        public void del(){
            userDao.delete(5);
        }

*  查询

findOne(主键) 及时加载

getOne(主键) 懒加载会出现no session问题 解决方式 @Transactional

（查单条数据）

@Test
        public void sel(){
            User us = userDao.findOne(3);
            System.out.println(us);
        }

（查所有数据）

@Test
        public void selAll(){
            List<User> userList = userDao.findAll();
            System.out.println(userList);
        }

#### 三、复杂查询 ####

*  排序查询

@Test
        public void selSort(){
            Sort sort = new Sort(Sort.Direction.DESC,"id");
            List<User> all = userDao.findAll(sort);
            System.out.println(all);
        }

*  分页查询

@Test
        public void selpage(){
            Pageable pageable = new PageRequest(0, 3);
            Page<User> userPage = userDao.findAll(pageable);
            System.out.println(userPage.getContent());
        }

*  JPQL语句查询（需要在dao层写JPQL语句）

@Query("from User where username=?1")
        User login(String username);

测试类中

@Test
        public void login(){
            User user = userDao.login("2");
            System.out.println(user);
        }

*  SQL语句查询（需要在dao层写SQL语句）

@Query(value = "select * from t_users where username=?",nativeQuery = true)
        User login2(String username);

测试类中

@Test
        public void login2(){
            User user = userDao.login2("华仔");
            System.out.println(user);
        }

*  特殊方法名查询（需要在dao层写特殊方法名）

User findByUsernameAndPwd(String username,String pwd);

*  动态查询

@Test
        public void selT(){
           Specification<User> specification = new Specification<User>() {
               @Override
               public Predicate toPredicate(Root<User> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
                   Path<User> username = root.get("username");
                   Path<User> pwd = root.get("pwd");
                   Predicate predicate1 = criteriaBuilder.equal(username, "杨滢");
                   Predicate predicate2 = criteriaBuilder.equal(pwd, "666");
    
                   Predicate predicate = criteriaBuilder.or(predicate1, predicate2);
    
                   return predicate;
               }
           };
            List<User> userList = userDao.findAll(specification);
            System.out.println(userList);
        }