使用REST模板和JSON响应格式在Spring MVC上返回的Http Status 500

debugcn 发表于 Dev

阿林丹·达斯（Arindam Das）

我的项目由以下四个表组成：

问题-Question_id，问题文字
用户-用户ID，名称
Question_Answer-用户ID，Question_ID，答案
QuestionType -QuestionID，标签

我必须根据多个标签生成问题

或仅返回所有问题的列表（如果未提供标签）

或将用户提供的答案插入Question_Answer表中。

Controller类SpringServiceController.java（以JSON格式生成结果）如下：

package com.bargadss.SpringService.Controller;

import java.text.ParseException;
import java.util.List;

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.bargadss.SpringService.DAO.QuestionService;
import com.bargadss.SpringService.Domain.*;


@RestController

@RequestMapping("/service/question/")
public class SpringServiceController {
  QuestionService questionService=new QuestionService();

 @RequestMapping(value = "/{tag1},{tag2},{tag3}", method =  RequestMethod.GET,headers="Accept=application/json")
 public List<Questions> getQuestions(@PathVariable("tag1") String tag1, @PathVariable("tag2") String tag2, @PathVariable("tag3") String tag3) {
  List<Questions> Qobj=questionService.getQuestionByTag(tag1, tag2, tag3);
  return Qobj;
 }

 @RequestMapping(method = RequestMethod.GET,headers="Accept=application/json")
 public List<Questions> getAllQuestions() {  
  List<Questions> Qobj=questionService.getAllQuestion();
  return Qobj;   
 }

 @RequestMapping(value="/insert/{user_id}/{question_id}/{answer}",method = RequestMethod.POST,headers="Accept=application/json")
  public List<Questions> addQuestions(@PathVariable int user_id,@PathVariable int question_id,@PathVariable String answer) throws ParseException { 
      Question_Answer qtnAns = new Question_Answer();
      qtnAns.setUser_id(user_id);
      qtnAns.setQuestion_id(question_id);
      qtnAns.setAnswer(answer);
      questionService.insertAnswer(qtnAns.getUser_id(), qtnAns.getQuestion_id(), qtnAns.getAnswer());
      return questionService.getAllQuestion();        
  }        
  }

该ListQuestionController.java使用Spring REST temaplate（生成JSP页面）如下：

package com.bargadss.SpringService.Controller;

import java.util.LinkedHashMap;
import java.util.List;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.servlet.ModelAndView;

import com.bargadss.SpringService.Domain.*;

@Controller
public class ListQuestionController {

 @RequestMapping("/listQuestion/{tag1},{tag2},{tag3}")
    public ModelAndView listQuestions(@PathVariable("tag1") String Tag1, @PathVariable("tag2") String Tag2, @PathVariable("tag3") String Tag3) { 
        RestTemplate restTemplate = new RestTemplate();
        String url="http://localhost:8080/FetchQuestions/service/question/{tag1},{tag2},{tag3}";
        List<LinkedHashMap> Qobj=restTemplate.getForObject(url, List.class,Tag1,Tag2,Tag3);
        return new ModelAndView("listQuestion", "questions", Qobj);
    }

 @RequestMapping("/listAllQuestion/")
    public ModelAndView listAllQuestion() { 
        RestTemplate restTemplate = new RestTemplate();
        String url="http://localhost:8080/FetchQuestions/service/question/";
        List<LinkedHashMap> Qobj=restTemplate.getForObject(url, List.class);
        return new ModelAndView("listQuestion", "questions", Qobj);
    }

 @RequestMapping("/insertQuestionAnswer/{user_id}/{qtn_id}/{answer}")
    public ModelAndView insertQuestionAnswer(@PathVariable("user_id") String user_ID,
           @PathVariable("qtn_id") String qtn_ID, @PathVariable("answer") String answer) { 
        RestTemplate restTemplate = new RestTemplate();
        String url="http://localhost:8080/FetchQuestions/service/question/insert/{user_id}/{qtn_id}/{answer}";
        List<LinkedHashMap> Qobj=restTemplate.getForObject(url, List.class,user_ID,qtn_ID,answer);
        return new ModelAndView("listQuestion", "questions", Qobj);
    }

  }

所述QuestionService.java类执行DAO活性如下：

package com.bargadss.SpringService.DAO;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.List;
import com.bargadss.SpringService.Domain.*;
import com.bargadss.SpringService.Utility.DBUtility;


public class QuestionService {

private Connection connection;

 public QuestionService() {
  connection = DBUtility.getConnection();
 }

 public void insertAnswer(int userId,int qtnId,String answer){
    //Question_Answer objQA = new Question_Answer();
    PreparedStatement preparedStatement = null;
    try{
         preparedStatement = connection.prepareStatement("insert into question_answer values (?,?,?)");
         preparedStatement.setInt(1, userId);
         preparedStatement.setInt(2, qtnId);
         preparedStatement.setString(3, answer);
         int result = preparedStatement.executeUpdate();
         if(result == 0)
            System.out.println("INSERTION OF DATA FAILED");
    } catch (SQLException e){
         e.printStackTrace();
    }
    finally{
        try { if (preparedStatement != null) preparedStatement.close(); } catch (Exception e) {System.out.println("Exception Closing The Prepared Statement");e.printStackTrace();};
    }
 }

 public List<Questions> getAllQuestion(){
     Questions objQ = new Questions();
     ResultSet rs = null;
     PreparedStatement preparedStatement = null;
     List<Questions> qtns = new ArrayList<Questions>();
     try {
           preparedStatement = connection.prepareStatement("select * from questions");             
           rs = preparedStatement.executeQuery();

           while(rs.next()) {
            objQ.setQuestion_id(Integer.parseInt( rs.getString("Question_id") ) );
            objQ.setQuestion_text(rs.getString("Question_Text"));
            qtns.add(objQ);   
           }
     } catch (SQLException e) {
           e.printStackTrace();
       }    
       finally{
           try { if (rs != null) rs.close(); } catch (Exception e) {System.out.println("Exception Closing The result Set");e.printStackTrace();};
           try { if (preparedStatement != null) preparedStatement.close(); } catch (Exception e) {System.out.println("Exception Closing The Prepared Statement");e.printStackTrace();};
           /*try { if (connection != null) connection.close(); } catch (Exception e) {System.out.println("Exception Closing The Connection");e.printStackTrace();};*/
       }
    return qtns;
 }

 public List<Questions> getQuestionByTag(String Tag1,String Tag2,String Tag3){       
     Questions objQ = new Questions();
     ResultSet rs = null;
     PreparedStatement preparedStatement = null;
     List<Questions> qtns = new ArrayList<Questions>();
     try {
           preparedStatement = connection.
           prepareStatement("select questions.Question_id,questions.Question_Text from questions,questiontype " +
                            "where questions.Question_id=questiontype.Question_id " +
                            "and questiontype.Tag in (?,?,?)");
           preparedStatement.setString(1, Tag1);
           preparedStatement.setString(2, Tag2);
           preparedStatement.setString(3, Tag3);
           rs = preparedStatement.executeQuery();

           while(rs.next()) {
            objQ.setQuestion_id(Integer.parseInt( rs.getString("Question_id") ) );
            objQ.setQuestion_text(rs.getString("Question_Text"));
            qtns.add(objQ);   
           }
     } catch (SQLException e) {
           e.printStackTrace();
       }    
       finally{
           try { if (rs != null) rs.close(); } catch (Exception e) {System.out.println("Exception Closing The result Set");e.printStackTrace();};
           try { if (preparedStatement != null) preparedStatement.close(); } catch (Exception e) {System.out.println("Exception Closing The Prepared Statement");e.printStackTrace();};
           /*try { if (connection != null) connection.close(); } catch (Exception e) {System.out.println("Exception Closing The Connection");e.printStackTrace();};*/
       }
    return qtns;
}

}

在执行具有以下URL的项目（Apache Tomcat 7.0.12）时，它将生成HTTP STATUS 500

http://localhost:8080/FetchQuestions/insertQuestionAnswer/3/9/True

同样，当我执行以下URL时，它也会生成HTTP状态405-不支持请求方法“ GET”

http://localhost:8080/FetchQuestions/service/question/insert/3/9/True

我究竟做错了什么？我想念什么吗？

HTTP状态500的堆栈跟踪如下：

严重：路径为[/ FetchQuestions]的上下文中的servlet [rest]的Servlet.service（）抛出异常[请求处理失败；嵌套的异常是org.springframework.web.client.HttpClientErrorException：“ 405方法不允许”，根本原因是org.springframework.web.client.HttpClientErrorException：405.org.springframework.web.client.DefaultResponseErrorHandler.handleError（DefaultResponseErrorHandler。 org.springframework.web.client.RestTemplate.handleResponseError（RestTemplate.java:576）的org.springframework.web.client.RestTemplate.doExecute（RestTemplate.java:532）的org.springframework.web.client的java：91） org.springframework.web.client.RestTemplate.getForObject（RestTemplate.java:226）上的.RestTemplate.execute（RestTemplate.java:489）在com.bargadss.SpringService.Controller.ListQuestionController上。

希希尔·库马尔（Shishir Kumar）

同样，当我执行以下URL时，它也会生成HTTP状态405-不支持请求方法“ GET”

将方法的请求SpringServiceController.SpringServiceController方法从更改POST为GET。它应该可以解决您的问题。

@RequestMapping(value="/insert/{user_id}/{question_id}/{answer}",method = RequestMethod.GET,headers="Accept=application/json")

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编辑于2021-06-8

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