spring boot 链接额

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文本将对在Spring Boot构建的Web应用中，基于MYSQL数据库的几种数据库连接方式进行介绍。

包括JDBC、JPA、多数据源和事务。

开发工具：sts

1、属性配置文件（application.properties）

spring:
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/zzch
username: root
password: password
jpa:
hibernate:
ddl-auto: update
show-sql: true

在这里值得一提的是，无论是Spring Boot默认的DataSource配置还是你自己的DataSource bean，都会引用到外部属性文件中的属性配置。所以假设你自定义的DataSource bean，你可以在定义bean时设置属性，也可以在属性文件中，以“spring.datasource.*”的方式使属性配置外部化。

2、pom.xml 配置maven依赖

<groupId>mysql</groupId>

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

</dependency>

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

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

</dependency>

3、Java代码范例

package com.b505.bean;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name="user")
public class User {
@Id//告诉系统id为主键
@GeneratedValue//对主键提供生成策略
private Integer id;
@Column(name = "name")
private String name;
@Column(name = "age")
private int age;
@Column(name = "hobby")
private String hobby;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getHobby() {
return hobby;
}
public void setHobby(String hobby) {
this.hobby = hobby;
}
}

com.b505.dao.UserDao.java

package com.b505.dao;
import org.springframework.data.jpa.repository.JpaRepository;
import com.b505.bean.User;
public interface UserDao extends JpaRepository<User, Integer> {
/**
* JpaRepository接口的方法
* delete删除或批量删除
* findAll查询所用
* findOne查询单个
* save保存单个或保存批量
* saveAndFlush保存并刷新到数据库
* */
}

com.b505.web.UserController.java

package com.b505.web;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import com.b505.bean.User;
import com.b505.dao.UserDao;
import com.fasterxml.jackson.core.sym.Name;
@RestController
public class UserController {
@Autowired
private UserDao userDao;
//删除
@RequestMapping(value ="/delete" ,method = RequestMethod.POST)
public void weekdaylDelete(@RequestParam("id") Integer id){
System.out.println("删除执行");
userDao.delete(id);
}
//添加
@RequestMapping(value ="/add" ,method = RequestMethod.POST)
public void weekdayAdd(@RequestParam("name") String name,
@RequestParam("age") Integer age,@RequestParam("hobby") String hobby
){
User user = new User();
user.setName(name);
user.setAge(age);
user.setHobby(hobby);
userDao.save(user);
}
//查询所有
@RequestMapping(value ="/getall" ,method = RequestMethod.GET)
public List<User> girlList(){
System.out.println("查询所有执行");
return userDao.findAll();
}
//更改
@RequestMapping(value="/update",method = RequestMethod.POST)
public void weekdayUpdate(@RequestParam("id") Integer id,@RequestParam("name") String name,
@RequestParam("age") Integer age,@RequestParam("hobby") String hobby)
{
User user =new User();
System.out.println("2");
user=userDao.findOne(id);
if(user==null)
System.out.println("1");
if(name!=null)
user.setName(name);
//System.out.println(user.getName());
if(age!= 0)
user.setAge(age);
if(hobby!=null)
user.setHobby(hobby);
userDao.save(user);
System.out.println("1");
}
}

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