开发人员必须要掌握的《Spring Data JPA四种查询方式》

x33g5p2x  于2021-12-24 转载在 Spring  
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一、SpringDataJPa

介绍springDataJPa

SpringDataJpa,jpa,hibernate之间的关系

二、搭建环境

1.创建Maven工程,导入坐标

2.编写SpringDataJPA的配置文件(applicationContext.xml)

3.创建实体类,数据库表

4.数据库表的SQL

5.DAO接口

三、四种查询方式:

1.基本的增删改查  

JpaRepository封装好的方法

JpaSpecificationExecutor封装好的方法

测试类

2.JPQL查询  

DAO接口:

测试类:

3.SQL查询

DAO接口

测试类:

4.方法命名查询

部分对照表

DAO接口:

测试类:

一、SpringDataJPa

介绍springDataJPa

Spring Data JPA 是 Spring 基于 ORM 框架、JPA 规范的基础上封装的一套JPA应用框架,可使开发者用极简的代码即可实现对数据库的访问和操作。它提供了包括增删改查等在内的常用功能,且易于扩展!学习并使用 Spring Data JPA 可以极大提高开发效率!

Spring Data JPA 是更大的 Spring Data 系列的一部分,可以轻松实现基于 JPA 的存储库。该模块处理对基于 JPA 的数据访问层的增强支持。它使构建使用数据访问技术的 Spring 驱动的应用程序变得更加容易。

**SpringDataJPA其实是对JPA规范的封装抽象,**底层还是使用了Hibernate的JPA技术实现,引用JPQL(Java Persistence Query Language)查询语言,属于Spring整个生态体系的一部分。随着Spring Boot和Spring Cloud在市场上的流行,Spring Data JPA也逐渐进入大家的视野,它们组成有机的整体,使用起来比较方便,加快了开发的效率,使开发者不需要关心和配置更多的东西,完全可以沉浸在Spring的完整生态标准实现下。JPA上手简单,开发效率高,对对象的支持比较好,又有很大的灵活性,市场的认可度越来越高。

官网地址Spring Data JPA

SpringDataJpa,jpa,hibernate之间的关系

底层工作的还是Hibernate,听说啊,JPA与Hibernate的创始人是同一人。

二、搭建环境

1.创建Maven工程,导入坐标

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>JPA</artifactId>
        <groupId>com.dynamic</groupId>
        <version>1.0.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>JPA-Day2</artifactId>
    <properties>
        <spring.version>5.0.2.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>5.1.6</mysql.version>
    </properties>

    <dependencies>
        <!-- junit单元测试 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>

        <!-- spring beg -->
        <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>

        <!-- spring对orm框架的支持包-->
        <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>

        <!-- spring end -->

        <!-- hibernate beg -->
        <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>
        <!-- hibernate end -->

        <!-- c3p0 beg -->
        <dependency>
            <groupId>c3p0</groupId>
            <artifactId>c3p0</artifactId>
            <version>${c3p0.version}</version>
        </dependency>
        <!-- c3p0 end -->

        <!-- log end -->
        <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>
        <!-- log end -->

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>

        <!-- spring data jpa 的坐标-->
        <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>${spring.version}</version>
        </dependency>

        <!-- el beg 使用spring data jpa 必须引入 -->
        <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>
        <!-- el end -->
    </dependencies>


</project>

2.编写SpringDataJPA的配置文件(applicationContext.xml)

<?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">

    <!-- 1.dataSource 配置数据库连接池-->
    <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/jpa" />
        <property name="user" value="root" />
        <property name="password" value="root" />
    </bean>

    <!-- 2.配置entityManagerFactory -->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="packagesToScan" value="com.dynamic.domain" />
        <property name="persistenceProvider">
            <bean class="org.hibernate.jpa.HibernatePersistenceProvider" />
        </property>
        <!--jpa的供应商适配器 -->
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <!--配置是否自动创建数据库表 -->
                <property name="generateDdl" value="false" />
                <!--指定数据库类型 -->
                <property name="database" value="MYSQL" />
                <!--数据库方言:支持的特有语法 -->
                <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect" />
                <!--是否显示sql -->
                <property name="showSql" value="true" />
            </bean>
        </property>
        <!--jpa的方言 :高级的特性 -->
        <property name="jpaDialect" >
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
        </property>

    </bean>

    <!-- 3.事务管理器-->
    <!-- JPA事务管理器  -->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>

    <!-- 整合spring data jpa-->
    <jpa:repositories base-package="com.dynamic.dao"
                      transaction-manager-ref="transactionManager"
                      entity-manager-factory-ref="entityManagerFactory"></jpa:repositories>

    <!-- 4.txAdvice-->
    <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>

    <!-- 5.aop-->
<!--    <aop:config>-->
<!--        <aop:pointcut id="pointcut" expression="execution(* com.dynamic.service.*.*(..))" />-->
<!--        <aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut" />-->
<!--    </aop:config>-->

    <context:component-scan base-package="com.dynamic"></context:component-scan>

    <!--组装其它 配置文件-->

</beans>

3.创建实体类,数据库表

package com.dynamic.domain;

import javax.persistence.*;

/**
 * @Author: Promsing(张有博)
 * @Date: 2021/10/13 - 17:29
 * @Description: 客户的实体类
 *            配置映射关系
 *              1.实体类和表的映射关系
     *            @Entity 声明是实体类
     *            @Table(name = "cst_customer")  实体类与表的映射关系,name配置表的名称
 *
 *               2.实体类中属性和表字段的映射关系
 * @version: 1.0
 */
@Entity
@Table(name = "cst_customer")
public class Customer {

    /**
     * @Id:声明主键的配置
     * @GeneratedValue:配置主键的生成策略
     *      strategy
     *          GenerationType.IDENTITY :自增,mysql
     *                 * 底层数据库必须支持自动增长(底层数据库支持的自动增长方式,对id自增)
     *          GenerationType.SEQUENCE : 序列,oracle
     *                  * 底层数据库必须支持序列
     *          GenerationType.TABLE : jpa提供的一种机制,通过一张数据库表的形式帮助我们完成主键自增
     *          GenerationType.AUTO : 由程序自动的帮助我们选择主键生成策略
     * @Column:配置属性和字段的映射关系
     *      name:数据库表中字段的名称
     */
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "cust_id")
    private Long id;//主键

    @Column(name="cust_name")
    private String custName;

    @Column(name="cust_source")
    private String custSource;

    @Column(name = "cust_industry")
    private String custIndustry;//所属行业

    @Column(name="cust_level")
    private String custLevel;

    @Column(name = "cust_address")
    private String custAddress;

    @Column(name = "cost_phone")
    private String custPhone;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getCustName() {
        return custName;
    }

    public void setCustName(String custName) {
        this.custName = custName;
    }

    public String getCustSource() {
        return custSource;
    }

    public void setCustSource(String custSource) {
        this.custSource = custSource;
    }

    public String getCustIndustry() {
        return custIndustry;
    }

    public void setCustIndustry(String custIndustry) {
        this.custIndustry = custIndustry;
    }

    public String getCustLevel() {
        return custLevel;
    }

    public void setCustLevel(String custLevel) {
        this.custLevel = custLevel;
    }

    public String getCustAddress() {
        return custAddress;
    }

    public void setCustAddress(String custAddress) {
        this.custAddress = custAddress;
    }

    public String getCustPhone() {
        return custPhone;
    }

    public void setCustPhone(String custPhone) {
        this.custPhone = custPhone;
    }

    @Override
    public String toString() {
        return "Customer{" +
                "id=" + id +
                ", custName='" + custName + '\'' +
                ", custSource='" + custSource + '\'' +
                ", custIndustry='" + custIndustry + '\'' +
                ", custLevel='" + custLevel + '\'' +
                ", custAddress='" + custAddress + '\'' +
                ", custPhone='" + custPhone + '\'' +
                '}';
    }
}

4.数据库表的SQL

CREATE TABLE `cst_customer` (
  `cust_id` bigint(32) NOT NULL AUTO_INCREMENT COMMENT '客户编号(主键)',
  `cust_name` varchar(32) NOT NULL COMMENT '客户名称(公司名称)',
  `cust_source` varchar(32) DEFAULT NULL COMMENT '客户信息来源',
  `cust_industry` varchar(32) DEFAULT NULL COMMENT '客户所属行业',
  `cust_level` varchar(32) DEFAULT NULL COMMENT '客户级别',
  `cust_address` varchar(128) DEFAULT NULL COMMENT '客户联系地址',
  `cust_phone` varchar(64) DEFAULT NULL COMMENT '客户联系电话',
  `cost_phone` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`cust_id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

5.DAO接口

package com.dynamic.dao;

import com.dynamic.domain.Customer;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;

import java.util.List;

/**
 * @Author: Promsing(张有博)
 * @Date: 2021/10/17 - 17:36
 * @Description: 需要符合springDataJPA的dao层接口规范
 *          JpaRepository<操作的实体类型,实体类中主键属性的类型>
 *              *封装了基本的CRUD操作
 *          JpaSpecificationExecutor<操作的实体类型>
 *              *封装了复杂查询(分页)
 * @version: 1.0
 */
public interface CustomerDao extends JpaRepository<Customer,Long>, JpaSpecificationExecutor<Customer> {

  

}

三、四种查询方式:

1.基本的增删改查  

继承JpaRepository,JpaSpecificationExecutor 接口,使用JPA封装好的方法。

JpaRepository封装好的方法

JpaSpecificationExecutor封装好的方法

测试类

/**
     * findOne(id) :根据id查询
     *
     * save(customer):保存或更新  实体的id属性
     *
     * delete(id)  :根据id删除
     *
     * findAll()   :查询全部
     *
     * count()   :计数
     *
     * exists()  :判断是否存在
     *
     */   
@Test
    public void testFindOne(){
        System.out.println("dfa");
        Customer one = dao.findOne(1L);
        System.out.println(one);
    }

    @Test
    public void testSave(){
        System.out.println("dfa");
        Customer c=new Customer();
        c.setCustAddress("廊坊");
        c.setCustName("小小张");
        c.setCustPhone("9999");
        c.setCustLevel("vipp");
        Customer save = dao.save(c);
        System.out.println(save);
    }

    @Test
    @Transactional
    public void testUpdate(){
        System.out.println("dfa");
        Customer c=new Customer();
        c.setCustAddress("廊坊");
        c.setCustName("小小张");
        c.setCustPhone("2800");
        Customer save = dao.save(c);
        System.out.println(save);
    }

    @Test
    public void testDelete(){

        dao.delete(2L);
        System.out.println();
    }

    @Test
    @Transactional
    public void testFindAll(){

        List<Customer> all = dao.findAll();
        for (Customer customer : all) {
            System.out.println(customer);
        }
        System.out.println();
    }

    @Test
    @Transactional
    public void testCount(){

        long count = dao.count();
        System.out.println(count);

    }

    @Test
    public void testExists(){

        boolean exists = dao.exists(2L);
        System.out.println(exists);

    }
    @Test
    @Transactional
    public void testGetOne(){
        // getOone方法是懒加载
        Customer one = dao.getOne(2L);
        System.out.println(one);

    }

2.JPQL查询  

jpa query language  (jpq查询语言),与原生SQL语句类似,并且完全面向对象,通过类名和属性访问,查询的是类和类中的属性

上一篇博客介绍了JPQL:

JPA入门案例完成增删改查_小小张自由—>张有博-CSDN博客JPA (Java Persistence API) Java持久化API。是一套Java官方制定的ORM方案。JPA是一种规范,一种标准,具体的操作交给第三方框架去实现,比如说Hibernate,OpenJPA等。本文介绍了ORM思想,JPA规范与实现,如何去搭建JPA的基础环境,JPA的操作步骤以及使用Java代码用JPA做基本数据的增删改查。

https://blog.csdn.net/promsing/article/details/120794681
需要将JPQL语句配置到接口方法上

1.特有的查询:需要在dao接口上配置方法

2.在新添加的方法上,使用注解的形式配置jpql查询语句

3.注解 : @Query

DAO接口:

/**
 * @Author: Promsing(张有博)
 * @Date: 2021/10/17 - 17:36
 * @Description: 需要符合springDataJPA的dao层接口规范
 *          JpaRepository<操作的实体类型,实体类中主键属性的类型>
 *              *封装了基本的CRUD操作
 *          JpaSpecificationExecutor<操作的实体类型>
 *              *封装了复杂查询(分页)
 * @version: 1.0
 */
public interface CustomerDao extends JpaRepository<Customer,Long>, JpaSpecificationExecutor<Customer> {


    /**
     * @Query:表示查询
     *
     * @Modifying 表示更新的操作
     */
    @Query(value = "from Customer where custName = ? ")
    public List<Customer> findJpql(String custName);

    /**
     * 对于多个占位符参数
     *    赋值的时候,默认情况下,占位符的位置需要和方法参数中的位置保持一致
     *
     *  可以指定占位符参数的位置
     *      ? 索引的方式,指定此占位符的取值来源
     */
    @Query(value = "from Customer where custName = ? and id = ?")
   // @Query(value = "from Customer where custName = ?2 and id = ?1")
    public Object findCustNameAndId(String name,Long id);


    @Query(value = "update Customer set custName = ? where id = ? ")
    @Modifying //表示是,更新的操作
    public Integer updateName(String name,Long id);

}

测试类:

@Test
    public void testJpql(){

        List<Customer> list = dao.findJpql("小小张");
        System.out.println(list);

    }

    @Test
    public void testFindCustNameAndId(){

        Object one = dao.findCustNameAndId("小小张",1L);
        System.out.println(one);

    }

    @Test
    @Transactional //添加事务的支持
    @Rollback(value = false)
    /**
     * springDataJpa中使用jpql完成更新/删除操作
     *              需要手动添加事务的支持
     *              默认会执行结束之后,回滚事务
     * @Rollback: 设置是否自动回滚
     *             false(不)  | true
     */
    public void testUpdateName(){

        Object one = dao.updateName("张自由",3L);
        System.out.println(one);

    }

3.SQL查询

1.特有的查询:需要在dao接口上配置方法

2.在新添加的方法上,使用注解的形式配置sql查询语句

3.注解 : @Query

 value :jpql语句 | sql语句

 nativeQuery :false(使用jpql查询) | true(使用本地查询:sql查询)

DAO接口

package com.dynamic.dao;

import com.dynamic.domain.Customer;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;

import java.util.List;

/**
 * @Author: Promsing(张有博)
 * @Date: 2021/10/17 - 17:36
 * @Description: 需要符合springDataJPA的dao层接口规范
 *          JpaRepository<操作的实体类型,实体类中主键属性的类型>
 *              *封装了基本的CRUD操作
 *          JpaSpecificationExecutor<操作的实体类型>
 *              *封装了复杂查询(分页)
 * @version: 1.0
 */
public interface CustomerDao extends JpaRepository<Customer,Long>, JpaSpecificationExecutor<Customer> {


    /**
     * 使用sql的形式查询  查询全部用户
     *    SQL:select * from cst_customer
     * @Query: 配置sql查询
     *    value:sqly语句
     *    nativeQuery:查询方式
     *        true:sql查询
     *        false:jpql查询
     * @return
     */
    @Query(value = "select * from cst_customer", nativeQuery = true)
    public List<Customer> findSql();
    

    @Query(value = "select * from cst_customer where  cust_name like ?", nativeQuery = true)
    public List<Customer> findLikeSql(String name   );


}

测试类:

@Test
    public void testSQL(){
        List<Customer> list = dao.findSql();

        List<Customer> sql = dao.findLikeSql("小%");
        for (Customer customer : sql) {
            System.out.println(customer);
        }

    }

4.方法命名查询

是对jpql查询,更加深入一层的封装

我们只需要按照SpringDataJpa提供的方法名称规则定义方法,不需要再配置jpql语句,完成查询

按照Spring Data JPA 定义的规则,查询方法以findBy开头,涉及条件查询时,条件的属性用条件关键字连接,要注意的是:条件属性首字母需大写。框架在进行方法名解析时,会先把方法名多余的前缀截取掉,然后对剩下部分进行解析。

部分对照表

| <br> | <br> | <br> | <br> | <br> |
| <br>Keyword<br> | <br>Sample<br> | <br>JPQL<br> | <br> | <br> |
| <br>And<br> | <br>findByLastnameAndFirstname<br> | <br>… where x.lastname = ?1 and x.firstname = ?2<br> | <br> | <br> |
| <br>Or<br> | <br>findByLastnameOrFirstname<br> | <br>… where x.lastname = ?1 or x.firstname = ?2<br> | <br> | <br> |
| <br>Is,Equals<br> | <br>findByFirstnameIs,<br><br>findByFirstnameEquals<br> | <br>… where x.firstname = ?1<br> | <br> | <br> |
| <br>Between<br> | <br>findByStartDateBetween<br> | <br>… where x.startDate between ?1 and ?2<br> | <br> | <br> |
| <br>LessThan<br> | <br>findByAgeLessThan<br> | <br>… where x.age < ?1<br> | <br> | <br> |
| <br>LessThanEqual<br> | <br>findByAgeLessThanEqual<br> | <br>… where x.age ⇐ ?1<br> | <br> | <br> |
| <br>GreaterThan<br> | <br>findByAgeGreaterThan<br> | <br>… where x.age > ?1<br> | <br> | <br> |
| <br>GreaterThanEqual<br> | <br>findByAgeGreaterThanEqual<br> | <br>… where x.age >= ?1<br> | <br> | <br> |
| <br>After<br> | <br>findByStartDateAfter<br> | <br>… where x.startDate > ?1<br> | <br> | <br> |
| <br>Before<br> | <br>findByStartDateBefore<br> | <br>… where x.startDate < ?1<br> | <br> | <br> |
| <br>IsNull<br> | <br>findByAgeIsNull<br> | <br>… where x.age is null<br> | <br> | <br> |
| <br>IsNotNull,NotNull<br> | <br>findByAge(Is)NotNull<br> | <br>… where x.age not null<br> | <br> | <br> |
| <br>Like<br> | <br>findByFirstnameLike<br> | <br>… where x.firstname like ?1<br> | <br> | <br> |
| <br>NotLike<br> | <br>findByFirstnameNotLike<br> | <br>… where x.firstname not like ?1<br> | <br> | <br> |
| <br>StartingWith<br> | <br>findByFirstnameStartingWith<br> | <br>… where x.firstname like ?1 (parameter bound with appended %)<br> | <br> | <br> |
| <br>EndingWith<br> | <br>findByFirstnameEndingWith<br> | <br>… where x.firstname like ?1 (parameter bound with prepended %)<br> | <br> | <br> |
| <br>Containing<br> | <br>findByFirstnameContaining<br> | <br>… where x.firstname like ?1 (parameter bound wrapped in %)<br> | <br> | <br> |
| <br>OrderBy<br> | <br>findByAgeOrderByLastnameDesc<br> | <br>… where x.age = ?1 order by x.lastname desc<br> | <br> | <br> |
| <br>Not<br> | <br>findByLastnameNot<br> | <br>… where x.lastname <> ?1<br> | <br> | <br> |
| <br>In<br> | <br>findByAgeIn(Collection ages)<br> | <br>… where x.age in ?1<br> | <br> | <br> |
| <br>NotIn<br> | <br>findByAgeNotIn(Collection age)<br> | <br>… where x.age not in ?1<br> | <br> | <br> |
| <br>TRUE<br> | <br>findByActiveTrue()<br> | <br>… where x.active = true<br> | <br> | <br> |
| <br>FALSE<br> | <br>findByActiveFalse()<br> | <br>… where x.active = false<br> | <br> | <br> |
| <br>IgnoreCase<br> | <br>findByFirstnameIgnoreCase<br> | <br>… where UPPER(x.firstame) = UPPER(?1)<br> | <br> | <br> |

DAO接口:

package com.dynamic.dao;

import com.dynamic.domain.Customer;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;

import java.util.List;

/**
 * @Author: Promsing(张有博)
 * @Date: 2021/10/17 - 17:36
 * @Description: 需要符合springDataJPA的dao层接口规范
 *          JpaRepository<操作的实体类型,实体类中主键属性的类型>
 *              *封装了基本的CRUD操作
 *          JpaSpecificationExecutor<操作的实体类型>
 *              *封装了复杂查询(分页)
 * @version: 1.0
 */
public interface CustomerDao extends JpaRepository<Customer,Long>, JpaSpecificationExecutor<Customer> {


    /**
     * 方法名的约定
     *
     *        findBy:查询
     *        对象中的属性名(首字母大写),查询条件
     *
     *        findByCustName  根据客户名称查询
     *
     *          会根据方法名称进行解析 findBy  from XXX where custName
     * @param name
     * @return
     */
    //1.findBy +属性名称(根据属性名称进行完成匹配的查询=)
    public Customer findByCustName(String name   );

    //2.findBy +属性名称 +“查询方式”(Like | isNull)
    public List<Customer> findByCustNameLike(String name   );

    //3.findBy +属性名称 +“查询方式” +“多条件的连接符(and|or)” +属性名 +“查询方式”
    public Customer findByCustNameLikeAndCustIndustry(String name,String industry);

}

测试类:

@Test
    public void testFindNaming(){

        Customer custName = dao.findByCustName("张自由");
         System.out.println(custName);

        System.out.println("______________");

        List<Customer> byCustNameLike = dao.findByCustNameLike("小%");
        for (Customer customer : byCustNameLike) {
            System.out.println(customer);
        }

        System.out.println("______________");
        Customer it = dao.findByCustNameLikeAndCustIndustry("小%", "IT教育");
        System.out.println(it);
    }

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