1、去新建一个spring boot项目

目录结构如下：

然后我们去到

application.properties这个文件中：

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf8&useSSL=false  spring.datasource.username=root spring.datasource.password=root spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver spring.datasource.max-idle=10 spring.datasource.max-wait=10000 spring.datasource.min-idle=5 spring.datasource.initial-size=5 server.port=8011 server.session.timeout=10 server.tomcat.uri-encoding=UTF-8

（注意，绿色那块不是注释）

TestController类：

package com.example.demo2.controller; //按文件的实际路径来写 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 TestController { @Autowired private JdbcTemplate jdbcTemplate; @RequestMapping("/getUsers") public List<Map<String, Object>> getDbType(){ String sql = "select * from booktable"; 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; } }

2、去数据库建表

随后我们访问一下这个端口：localhost:8011/mydb/getUsers

成功拿到数据库中的数据