Java查询数据返回json数据(springboot项目)

 

 

package org.hxl.controller;

import java.sql.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.hxl.config.*;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.alibaba.fastjson.*;

@RestController
@RequestMapping("/api")
public class GetMysqlData {
    static final String sql = "select id,name,email from user limit 5";

    @GetMapping("/GetMysqlData")
    private String GetMysqlData() throws SQLException {

        Connection conn = DatabaseConnectionPool.getConnection();
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery(sql);

        Map resultData = new HashMap();
        resultData.put("code",0);
        resultData.put("msg","数据获取成功！");
        resultData.put("data",UserList(rs));
        JSONObject jsonObject = new JSONObject();
        String info = jsonObject.toJSONString(resultData);
        return info;
    }


    private static List UserList(ResultSet rs) throws SQLException{
        List list = new ArrayList();
        ResultSetMetaData resultSetMetaData = rs.getMetaData();
        int coulmnCount = resultSetMetaData.getColumnCount();
        while (rs.next()){
            Map rowData = new HashMap();
            for (int i =1 ; i <= coulmnCount ; i++){
                rowData.put(resultSetMetaData.getColumnName(i),rs.getObject(i));
            }
            list.add(rowData);
        }
        return list;
    }

}

 

http://localhost:8888/api/GetMysqlData