Spring Boot (四)：JdbcTemplate访问数据源

本文介绍在Spring Boot基础下配置数据源和通过JdbcTemplate编写数据访问的示例。
一、数据源配置
首先我们再pom.xml添加jdbc的依赖和mysql数据库的驱动

    org.springframework.boot
    spring-boot-starter-jdbc

    mysql
    mysql-connector-java
    5.1.21

在src/main/resources/application.properties中配置数据源信息

spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

二、代码部分
首先我们先创建一个springboot项目，我们的入口类SpringbootApplication.java

package com.guo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringbootApplication {

    public static void main(String[] args) {

        SpringApplication.run(SpringbootApplication.class, args);
    }

}

接着是我们的实体类User.java

package com.guo.domain;

public class User {
    private long id;
    private String name;
    private Integer age;

    public User() {
    }

    public User(String name, Integer age) {
        this.name = name;
        this.age = age;
    }

    public long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

接着定义一个json数据类用来响应结果JsonData.java

package com.guo.domain;

import java.io.Serializable;
public class JsonData implements Serializable {
	private static final long serialVersionUID = 1L;
	private Integer code; // 状态码 0 表示成功，1表示处理中，-1表示失败
	private Object data; // 数据
	private String msg;// 描述

	public JsonData() {
	}
	
	public JsonData(Integer code, Object data, String msg) {
		this.code = code;
		this.data = data;
		this.msg = msg;
	}

	// 成功，传入数据
	public static JsonData buildSuccess() {
		return new JsonData(0, null, null);
	}

	// 成功，传入数据
	public static JsonData buildSuccess(Object data) {
		return new JsonData(0, data, null);
	}

	// 失败，传入描述信息
	public static JsonData buildError(String msg) {
		return new JsonData(-1, null, msg);
	}

	// 失败，传入描述信息,状态码
	public static JsonData buildError(String msg, Integer code) {
		return new JsonData(code, null, msg);
	}

	// 成功，传入数据,及描述信息
	public static JsonData buildSuccess(Object data, String msg) {
		return new JsonData(0, data, msg);
	}

	// 成功，传入数据,及状态码
	public static JsonData buildSuccess(Object data, int code) {
		return new JsonData(code, data, null);
	}

	public Integer getCode() {
		return code;
	}

	public void setCode(Integer code) {
		this.code = code;
	}

	public Object getData() {
		return data;
	}

	public void setData(Object data) {
		this.data = data;
	}

	public String getMsg() {
		return msg;
	}

	public void setMsg(String msg) {
		this.msg = msg;
	}

	@Override
	public String toString() {
		return "JsonData [code=" + code + ", data=" + data + ", msg=" + msg
				+ "]";
	}

}

接着我们的控制类UserController.java

package com.guo.controller;

import com.guo.domain.JsonData;
import com.guo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;

    @GetMapping("/add")
    public void add(){
        userService.addUser("李三",11);
    }

    @GetMapping("/getUser")
    public Object addAccount() {
        int id = userService.getAllUsers();
        return JsonData.buildSuccess(id);
    }
}

接着我们定义一个接口类来实现业务功能 UserService.java

package com.guo.service;

public interface UserService {
    void addUser(String name, Integer age);

    void deleteByName(String name);

    Integer getAllUsers();

    void deleteAllUsers();

}

接着是我们的实现类UserServiceImpl.java

package com.guo.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public void addUser(String name, Integer age) {
        jdbcTemplate.update("insert into USER(NAME, AGE) values(?, ?)", name, age);
    }

    @Override
    public void deleteByName(String name) {
        jdbcTemplate.update("delete from USER where NAME = ?", name);
    }

    @Override
    public Integer getAllUsers() {
        return jdbcTemplate.queryForObject("select count(1) from USER", Integer.class);
    }

    @Override
    public void deleteAllUsers() {
        jdbcTemplate.update("delete from USER");
    }
}

执行 http://localhost:8080/user/add
接下来我们看结果：执行了两遍所以有2个

执行 http://localhost:8080/user/getUser

简单一个小例子来学习下。