springboot2.x整合JPA

项目结构

pom

<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/maven-v4_0_0.xsd">





	<modelVersion>4.0.0</modelVersion>





	<groupId>com.pwl.springboot-jpa</groupId>





	<artifactId>springboot-jpa</artifactId>





	<packaging>war</packaging>





	<version>0.0.1-SNAPSHOT</version>





	<name>Mybatis Maven Webapp</name>





	<url>http://maven.apache.org</url>





	<parent>





		<groupId>org.springframework.boot</groupId>





		<artifactId>spring-boot-starter-parent</artifactId>





		<version>2.0.1.RELEASE</version>





	</parent>





	<dependencies>





		<dependency>





			<groupId>junit</groupId>





			<artifactId>junit</artifactId>





			<scope>test</scope>





		</dependency>





		<dependency>





			<groupId>org.springframework.boot</groupId>





			<artifactId>spring-boot-starter-web</artifactId>





		</dependency>





		<dependency>





			<groupId>org.springframework.boot</groupId>





			<artifactId>spring-boot-starter-data-jpa</artifactId>





		</dependency>





		<dependency>





			<groupId>mysql</groupId>





			<artifactId>mysql-connector-java</artifactId>





		</dependency>





		<dependency>





			<groupId>org.springframework.boot</groupId>





			<artifactId>spring-boot-devtools</artifactId>





			<optional>true</optional>





		</dependency>





	</dependencies>





	<build>





		<plugins>





			<plugin>





				<groupId>org.apache.maven.plugins</groupId>





				<artifactId>maven-compiler-plugin</artifactId>





				<configuration>





					<source>1.8</source>





					<target>1.8</target>





				</configuration>





			</plugin>





		</plugins>





	</build>





 





</project>

然后配置数据库连接

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/springboot?useSSL=false





spring.datasource.username=root





spring.datasource.password=root





spring.datasource.driver-class-name=com.mysql.jdbc.Driver





 





spring.jpa.properties.hibernate.hbm2ddl.auto=update





spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect





spring.jpa.show-sql= true

实体类

package com.pwl.springboot.entity;





 





import javax.persistence.Entity;





import javax.persistence.Id;





import javax.persistence.Table;





 





@Entity





@Table(name="user") //指定数据库表名





public class User {





	@Id





	private String id;





	private String name;





	private String age;





	public String getId() {





		return id;





	}





	public void setId(String id) {





		this.id = id;





	}





	public String getName() {





		return name;





	}





	public void setName(String name) {





		this.name = name;





	}





	public String getAge() {





		return age;





	}





	public void setAge(String age) {





		this.age = age;





	}





}

service层

UserService接口

package com.pwl.springboot.service;





 





import com.pwl.springboot.entity.User;





 





public interface UserService {





	public User getUserByname(String name);





}

UserServiceImpl实现类

package com.pwl.springboot.service.impl;





 





import org.springframework.beans.factory.annotation.Autowired;





import org.springframework.stereotype.Service;





 





import com.pwl.springboot.dao.UserDao;





import com.pwl.springboot.entity.User;





import com.pwl.springboot.service.UserService;





 





@Service





public class UserServiceImpl implements UserService{





	@Autowired





	private UserDao userDao;





	@Override





	public User getUserByname(String name) {





		User user = userDao.findByName(name);





		return user;





	}





 





}

dao

package com.pwl.springboot.dao;





 





import org.springframework.data.jpa.repository.JpaRepository;





 





import com.pwl.springboot.entity.User;





 





public interface UserDao extends JpaRepository<User, String> {





	public User findByName(String name);





}

主要就是继承了JpaRepository

具体的关键字，使用方法和生产成SQL如下表所示

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

最后就是controller

package com.pwl.springboot.controller;





 





import org.springframework.beans.factory.annotation.Autowired;





import org.springframework.stereotype.Controller;





import org.springframework.web.bind.annotation.RequestMapping;





import org.springframework.web.bind.annotation.ResponseBody;





import com.pwl.springboot.entity.User;





import com.pwl.springboot.service.UserService;





 





@Controller





@RequestMapping("/")





public class HelloController {





	@Autowired





	private UserService userService;





 





	@RequestMapping("hello")





	@ResponseBody





	public String hello() {





		return "hello_world";





	}





 





	@RequestMapping("getUser")





	@ResponseBody





	public User getUser(String name) {





		return userService.getUserByname(name);





	}





 





}

测试结果

原文地址：https://blog.csdn.net/qq_38157516/article/details/82379078