springDataJpa学习笔记

青旅半醒 2021-09-29 06:56 374阅读 0赞

*  前言
 *  springData
    
     *  准备
        
         *  引用
         *  xml配置初始化JPA
     *  pojo
     *  dao层接口
     *  使用
        
         *  新增、修改：save
         *  删除
         *  查询所有
         *  根据ID查询findById
         *  命名规则查询（条件查询）
         *  自定义JPQL查询（条件查询）
         *  自定义sql查询（条件查询）
         *  自定义update、delete
         *  Specification对象查询和分页
         *  一对多和多对多查询

# 前言 #

ORM框架，会大大减少重复性代码，开发速度快；

底层使用了hibernate；

# springData #

## 准备 ##

### 引用 ###

<dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>5.0.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-tx</artifactId>
        <version>5.0.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.8.7</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>5.0.2.RELEASE</version>
    </dependency>
    
    
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.6</version>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.12</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-c3p0</artifactId>
        <version>5.0.7.Final</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>5.0.7.Final</version>
    </dependency>
    
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-jpa</artifactId>
        <version>2.0.5.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-orm</artifactId>
        <version>5.0.2.RELEASE</version>
    </dependency>

### xml配置初始化JPA ###

<?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"
           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">
    
        
        <context:component-scan base-package="com.alvin"></context:component-scan>
    
        
        <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
            <property name="driverClass" value="com.mysql.jdbc.Driver" />
            <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/test" />
            <property name="user" value="root" />
            <property name="password" value="admin" />
        </bean>
    
        
        <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
            <property name="dataSource" ref="dataSource" />
            <property name="packagesToScan" value="com.alvin.domain" />
            <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>
        </bean>
    
    
        
        <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
            <property name="entityManagerFactory" ref="entityManagerFactory" />
        </bean>
    
        
        <jpa:repositories base-package="com.alvin.dao "
                          transaction-manager-ref="transactionManager"
                          entity-manager-factory-ref="entityManagerFactory">
    
        </jpa:repositories>
    
        
        <tx:advice id="txAdvice" transaction-manager="transactionManager">
            <tx:attributes>
                <tx:method name="get*" read-only="true" propagation="SUPPORTS"/>
                <tx:method name="find*" read-only="true" propagation="SUPPORTS"/>
                <tx:method name="*" propagation="REQUIRED" read-only="false"/>
            </tx:attributes>
        </tx:advice>
    
        
        <aop:config>
            <aop:pointcut id="pointcut" expression="execution(* com.alvin.service.*.*(..))" />
            <aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut" />
        </aop:config>
    </beans>

## pojo ##

和原生一样

## dao层接口 ##

public interface ICustomerDao extends JpaRepository<Customer,Integer>,JpaSpecificationExecutor<Customer>{
    }

## 使用 ##

### 新增、修改：save ###

Customer customer = new Customer();
    customer.setCustName("hello Spring data JPA");
    customerService.save(customer);

### 删除 ###

customerService.delete(1);

### 查询所有 ###

List<Customer> list = customerService.findAll();

### 根据ID查询findById ###

Customer customer = customerService.findById(1);
    System.out.println(customer);

### 命名规则查询（条件查询） ###

/**
     * 根据方法的命名规则查询
     *   拓展：
     *      约定大于配置（很重要的思想）
     * @param custName
     * @param custAddress
     * @return
     */
    List<Customer> findByCustNameAndCustAddressLike(StringcustName, String custAddress);

### 自定义JPQL查询（条件查询） ###

/**
     * 查询集合（带条件--JPQL）
     * @param custName
     * @param custAddress
     * @return
     */
    @Query("from Customer where custName = ?1 and custAddress like ?2")
    List<Customer> findAll(String custName, String custAddress);

### 自定义sql查询（条件查询） ###

/**
     * Sql
     * @param custName
     * @param custAddress
     * @return
     */
    @Query(value = "select * from cst_customer where cust_name = ?1 and cust_address like ?2",nativeQuery=true)
    List<Customer> findAllByNative(String custName, StringcustAddress);

### 自定义update、delete ###

/**
     * 自定更新
     * @param custId
     * @param custName
     * @param custAddress
     */
    @Query("update Customer set custName = ?2,custAddress = ?3 where custId = ?1")
    @Modifying
    void update(Integer custId, String custName, StringcustAddress);

### Specification对象查询和分页 ###

> 方便拼接查询条件

查询

//创建Specification对象 select * from cst_customer where
    Specification<Customer> specification = new Specification<Customer>() {
        @Override
        public Predicate toPredicate(Root<Customer> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
            // 条件
            Predicate p1 = criteriaBuilder.equal(root.get("custName"), "客户2");
            Predicate p2 = criteriaBuilder.like(root.get("custAddress"), "%北%");
            return criteriaBuilder.and(p1,p2);
        }
    };
    
    List<Customer> all = service.findAll(specification);

分页

> 传入参数第几页，多少条！

//创建Specification对象 select * from cst_customer
    Specification<Customer> specification = new Specification() {
        @Nullable
        @Override
        // 此内部方法只是负责拼接条件及参数
        public Predicate toPredicate(Root root, CriteriaQuery cq, CriteriaBuilder cb) {
            Predicate predicate = cb.and(cb.equal(root.get("custName"),"京西集团"),
                    cb.like(root.get("custAddress"),"%山%"));
            return null;
        }
    };
    
    Pageable pageable = PageRequest.of(1,2);
    Page<Customer> page = customerService.findAllByPage(specification, pageable);
    List<Customer> list = page.getContent();

### 一对多和多对多查询 ###

待补充

转载于:https://www.cnblogs.com/birdofparadise/p/10012287.html