Spring MVC中的Java到JSON对象映射结果400错误的请求错误

Question

I have some troubles when I recieve the json data from my application in app engine, some cases I recieve the json empty and in the log viewer of my application appears the following

    2014-07-03 16:46:21.193 /service/concentraciondeptos/ 400 43ms 0kb Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.153 Safari/537.36 module=default version=2
181.48.97.68 - - [03/Jul/2014:14:46:21 -0700] "GET /service/concentraciondeptos/ HTTP/1.1" 400 146 - "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.153 Safari/537.36" "Instance ID" ms=44 cpu_ms=80 cpm_usd=0.000016 app_engine_release=1.9.6 trace_id=e2164f3bbeb2302c384164569b22b8dd 

and here's my code

package com.servinfo.services.controller;

import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import com.servinfo.database.Manager;
import com.servinfo.services.AbstractController;
import com.servinfo.services.entity.ResponseObject;
import com.servinfo.services.entity.afe.ConcentracionDeptos;

@Controller
@RequestMapping("service/concentraciondeptos/*")
public class ConcentracionDeptosController {

    // private static final Logger log = Logger.getLogger("AreaTController");

    protected final static String RESPONSE_FORMAT = "application/json";

    private final static String GET = "";

    private static String STATE = "";

    private static String MESSAGE = "";


    @RequestMapping(value = GET, method = RequestMethod.GET, produces = RESPONSE_FORMAT)
    public @ResponseBody
    ResponseEntity<ResponseObject> getPoint() {

        if (getData().isEmpty()) {
            STATE = "ERROR";
            MESSAGE = ResponseObject.MSG_EMPTY;
        }

        // log.warning("Servicio areat");
        ResponseObject response = new ResponseObject(STATE, MESSAGE, getData());

        if (response.getStatus().equals("OK")) {
            return new ResponseEntity<ResponseObject>(response,
                    AbstractController.getHeader(), HttpStatus.OK);
        }

        return new ResponseEntity<ResponseObject>(response,
                AbstractController.getHeader(), HttpStatus.BAD_REQUEST);

    }

    public List<ConcentracionDeptos> getData() {
        STATE = "ERROR";
        MESSAGE = ResponseObject.MSG_ERROR;
        int intContador = 0;

        List<ConcentracionDeptos> result = new ArrayList<ConcentracionDeptos>();
        try {
            String sql = "select depto.coddane "
                    + ""
                    + "from departamentos as depto, proyecto as p, aporte_depto as apdepto,"
                    + "aporte_muni as apomuni, ciudades as ciu"
                    + " "
                    + "where apdepto.nit = p.nit and apdepto.id_proyecto = p.id "
                    + "and apdepto.coddane_depto = depto.coddane and apomuni.nit = p.nit "
                    + "and apomuni.id_proyecto = p.id and apomuni.coddane_ciudad = ciu.coddane";

            Manager mng = new Manager();
            ResultSet rs = mng.executeQuery(sql);
            if (rs.first()) {
                rs.beforeFirst();
                STATE = "OK";
                MESSAGE = ResponseObject.MSG_SUCCESS;
            } else {
                Thread.sleep(200);
                rs = mng.executeQuery(sql);
                if (rs.first()) {
                    rs.beforeFirst();
                    STATE = "OK";
                    MESSAGE = ResponseObject.MSG_SUCCESS;
                } else {
                    STATE = "ERROR";
                    MESSAGE = ResponseObject.MSG_ERROR;
                }
            }
            ConcentracionDeptos obEntity = new ConcentracionDeptos();
            while (rs.next()) {
                intContador++;
                obEntity.setCoddane(rs.getString("coddane"));
            }
            obEntity.setCantidadP(Integer.toString(intContador));
            result.add(obEntity);
            rs.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
}

when I execute the sql command in mysql I retrieve the correct information. and here's th connection code

import java.sql.*;
import com.google.appengine.api.utils.SystemProperty;

public class Manager {

    public ResultSet executeQuery(String sql){

        try{
            String url = null;
            if (SystemProperty.environment.value() == SystemProperty.Environment.Value.Production) {
                Class.forName("com.mysql.jdbc.GoogleDriver");
                url = "jdbc:google:mysql://ID:App ID/DB?user=root";
            } else {
                Class.forName("com.mysql.jdbc.Driver");
                url = "jdbc:mysql://IP:3306/afe_services?user=root&password=****";
            }

            Connection conn = DriverManager.getConnection(url);
            ResultSet rs = conn.createStatement().executeQuery(sql);
            return rs;

        }catch(Exception e){
            e.printStackTrace();
        }
        return null;
    }
}

what I'm doing bad?

Thanks.

Answer 1

EDIT 2:

After lengthy discussion the issue here is that there is no database connection and maintenance of session.

Thus when you call the database, it fails, thus the no connection error.

You need to setup your connection something like described in the spring.io/guides page. The web tutorial gives indepthy database connection and maintenance explanation.

for quick explanation or dirty version setup you can check out http://spring.io/guides/gs/relational-data-access/