Spring boot 使用 JDBC 数据库操作

使用 JDBC操作数据库

1. 创建一个springboot 项目，选择JDBC 依赖配置

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

2. 配置数据库信息

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# 这里使用的是MySql 8.0.15 数据库,需要加时区，保证自己的数据库db_jdbc 存在。
spring.datasource.url=jdbc:mysql://localhost:3306/db_jdbc?\
  useSSL=true&useUnicode=true&characterEncoding=utf8&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=666666

3.创建实体类

package com.zdy.springboot.pojo;

/**
 * @author deyou
 * @create 2020-03-27 11:53 PM
 */
public class User {
    private int id;
    private String user_name;
    private String user_password;

    public int getId() {
        return id;
    }

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

    public String getUser_name() {
        return user_name;
    }

    public void setUser_name(String user_name) {
        this.user_name = user_name;
    }

    public String getUser_password() {
        return user_password;
    }

    public void setUser_password(String user_password) {
        this.user_password = user_password;
    }

    public User() {
    }

    public User(int id, String user_name, String user_password) {
        this.id = id;
        this.user_name = user_name;
        this.user_password = user_password;
    }
}

4. 创建Controller 类

package com.zdy.springboot.controller;

import com.zdy.springboot.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.EmptyResultDataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * @author deyou
 * @create 2020-03-27 11:59 PM
 */
@RestController
public class UserController {
    @Autowired
    private JdbcTemplate jdbcTemplate;
    /*访问地址： http://localhost:8080/createTable*/
    @GetMapping("createTable")
    public String createTable(){
        String sql = "CREATE TABLE `user` (\n" +
                "  `id` int(11) NOT NULL AUTO_INCREMENT,\n" +
                "  `user_name` varchar(255) DEFAULT NULL,\n" +
                "  `user_password` varchar(255) DEFAULT NULL,\n" +
                "  PRIMARY KEY (`id`)\n" +
                ") ENGINE=InnoDB DEFAULT CHARSET=utf8;";
        jdbcTemplate.execute(sql);
       return "创建User表成功";
    }
    /*访问地址： http://localhost:8080/saveUser*/
    //保存数据
    @GetMapping("saveUser")
    public String saveUser(String username,String password){
        String sql = "INSERT INTO `user` (`user_name`, `user_password`) VALUES (?, ?)";
        int rows = jdbcTemplate.update(sql,username,password);
        return "执行成功，影响数据"+rows+"行";
    }
    //修改方法
    //http://localhost:8080/updateUserPassword?id=1&password=10000000
    //RestFul 风格：http://localhost:8080/updateUserPassword/1/123456789
    @GetMapping("updateUserPassword/{ID}/{pwd}")
    public String updateUserPassword(@PathVariable("ID") int id, @PathVariable("pwd") String password){
        String sql = "Update  user set user_password = " +
                "? where id=? ";
        int rows = jdbcTemplate.update(sql, password, id);
        return ("执行修改成功，影响"+rows+"行");
    }


    //删除方法
    //http://localhost:8080/deleteUserById/2
    @GetMapping("deleteUserById/{id}")
    public String deleteUserById(@PathVariable("id") int id){
        String sql = "delete from user where id = ?";
        int rows = jdbcTemplate.update(sql, id);
        return ("执行删除成功，影响"+rows+"行");
    }

    //通过名字查询
    //http://localhost:8080/queryUserbyUserName?username=deyou
    @GetMapping("queryUserbyUserName")
    public List<User> queryUserbyUserName(String username){
        String sql = "select * from user where user_name = ?";
        List<User> list = jdbcTemplate.query(sql, new Object[]{username}, new BeanPropertyRowMapper<>(User.class));
        return list;
    }

    //通过Id查询
    //http://localhost:8080/queryUserbyId?id=deyou
    @GetMapping("queryUserbyId")
    public User queryUserbyId(int  id){
        String sql = "select * from user where id = ?";
        /*添加一个查询不到数据的异常处理*/
        User user = null;
        try {
            user=jdbcTemplate.queryForObject(sql, new Object[]{id}, new BeanPropertyRowMapper<>(User.class));
        }catch (EmptyResultDataAccessException e){
            return null;
        }
        return  user;
    }

    //批处理添加数据
    //http://localhost:8080/batchSaveUser?num=10
    @GetMapping("batchSaveUser")
    public String batchSaveUser(int num){
        String sql = "INSERT INTO `user` (`user_name`, `user_password`) VALUES (?, ?)";
        List<Object[]> userList = new ArrayList<>();
        for (int i = 0; i < num ; i++) {
            String[] arr= new String[2];
            arr[0] = "zhangsan"+i;
            arr[1] = "password"+i;
            userList.add(arr);
        }
        int[] ints = jdbcTemplate.batchUpdate(sql, (userList));
        System.out.println(ints);
        return "执行成功";
    }
    //通过map 查询对象
    //http://localhost:8080/getMapUserById/10
    @GetMapping("getMapUserById/{id}")
    public Map getMapUserById(@PathVariable("id") int id){
        String sql = "select * from user where id =?";
        Map map =null;
        /*添加一个查询不到数据的异常处理*/
        try{
            map = jdbcTemplate.queryForMap(sql, id);
        }catch (EmptyResultDataAccessException e){
            return null;
        }

        return map;

    }

}