SpringBoot连接MySQL数据库

文章转载于：https://blog.yoodb.com/yoodb/article/detail/1416 

一、使用JdbcTemplate

    1、在pom.xml中添加依赖：

<dependency>	<!-- JDBC 数据库连接 -->
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>

    2、在src/main/resource文件夹下的application.properties文件中填写数据库配置信息:

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/emp  //数据库名
spring.datasource.username=root
spring.datasource.password=root   //密码
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.max-idle=10
spring.datasource.max-wait=1000
spring.datasource.min-idle=5
spring.datasource.initial-size=5
server.port=8012       //注意这里的端口
server.session.timeout=10
server.tomcat.uri-encoding=UTF-8

    3、在src/main/java文件夹下新建类文件:

package com.example.demo;

import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/mydb")
public class DBController {
	
	@Autowired
	private JdbcTemplate jdbcTemplate;
	
	@RequestMapping("/getUsers")	//访问路径：/mydb/getUsers
	public List<Map<String, Object>> getDbType(){
		String sql = "select * from emp";
		List<Map<String, Object>> list =  jdbcTemplate.queryForList(sql);
		
        for (Map<String, Object> map : list) {
            Set<Entry<String, Object>> entries = map.entrySet( );
            
                if(entries != null) {
                    Iterator<Entry<String, Object>> iterator = entries.iterator( );
                    
                    while(iterator.hasNext( )) {
	                    Entry<String, Object> entry =(Entry<String, Object>) iterator.next( );
	                    Object key = entry.getKey();
	                    Object value = entry.getValue();
	                    System.out.println(key+":"+value);
                }
            }
        }
        return list;
	}
	
	@RequestMapping("/user/{id}")
    public Map<String,Object> getUser(@PathVariable String id){
        Map<String,Object> map = null;
        
        List<Map<String, Object>> list = getDbType();
        
        for (Map<String, Object> dbmap : list) {
            
            Set<String> set = dbmap.keySet();
            
            for (String key : set) {
                if(key.equals("id")){    
                    if(dbmap.get(key).equals(id)){
                        map = dbmap;
                    }
                }
            }
        }
        
        if(map==null)
            map = list.get(0);
        return map;
    }
}

4、运行项目:

    ① 访问:http://localhost:8012/mydb/getUsers ,输出所有信息:

        控制台信息:

    

    ②访问http://localhost:8012/mydb/user/1 ,输出指定id的信息,但是有个问题,不管参数是多少,都只是显示第一个元素的信息,有待改正.