JPA全称(Java Persistence API),JPA 的目标之一是制定一个可以由很多供应商实现的API,不了解的小伙伴...emm虽然没人看,,可以看一下我的JPA系列学习笔记,JPA学习笔记emm..日后再改。
整个pom文件
<?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">
<modelVersion>4.0.0</modelVersion>
<groupId>com.yjj</groupId>
<artifactId>sb-first</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>sb-first</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!-- You can easily generate your own configuration metadata file
from items annotated with @ConfigurationProperties by using the
spring-boot-configuration-processor jar.
-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<!-- mysql连接-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<!-- jpa -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa
</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
配置文件application.yml加入
spring:
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&characterSetResults=utf8
username: root
password: 123456
jpa:
hibernate:
ddl-auto: update # 第一次简表create 后面用update
show-sql: true
注意,如果通过jpa在数据库中建表,将jpa.hibernate,ddl-auto改为create,建完表之后,要改为update,要不然每次重启工程会删除表并新建。
创建实体类
通过@Entity 表明是一个映射的实体类, @Id表明id, @GeneratedValue 字段自动生成
package com.yjj.sbfirst.entity;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
@Table(name="account")
@Entity
public class Account {
@Id
@GeneratedValue
private int id;
private String name;
private double money;
//省略getter setter
}
service层
package com.yjj.sbfirst.repository;
import com.yjj.sbfirst.entity.Account;
import org.springframework.data.jpa.repository.JpaRepository;
public interface AccountRepository extends JpaRepository<Account,Integer>{
}
Controller层
package com.yjj.sbfirst.controller;
import com.yjj.sbfirst.entity.Account;
import com.yjj.sbfirst.repository.AccountRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
@RestController
@RequestMapping(value = "/account")
public class AccountController {
@Autowired
AccountRepository accountRepository;
@RequestMapping(value="/list")
public List<Account> getAccounts(){
return accountRepository.findAll();
}
@RequestMapping(value = "/{id}",method = RequestMethod.GET)
public String getAccountById(@PathVariable("id") int id){
return accountRepository.findById(0).get().toString();
}
@RequestMapping(value = "/update/{id}",method = RequestMethod.POST)
public String updateAccount( @PathVariable("id") int id,@RequestParam(value="name",required = true) String name,
@RequestParam(value="money",required = true) double money){
Account account=new Account();
account.setMoney(money);
account.setName(name);
account.setId(id);
Account account1=accountRepository.saveAndFlush(account);
return account1.toString();
}
}
以上代码均测试过,就是有的没通过。。emm。。findOne和findByID返回Optional是怎么搞啊。。
查询全部和更新是可以的。嗯,暂时到这里
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