接口返回json数据后台封装

今天说下json数据格式，规范的格式应该是包括数据返回状态（一般就是false/true），状态码（比如200,7000，这个都是自己定义的），消息（比如“获取数据成功”/“获取数据失败”）,数据对象，以前写项目都是别人把方法写好，自己去调用，今天自己也写一个，其实很简单，老规矩直接上代码；

首先定义返回实体Result，这里面重点看下里面的构造函数，用了的方法的重载

package com.steven.utils.result;/*** 数据返回实体* @author Administrator**/
public class Result {private Integer code;//状态码private Boolean isSuccess;//状态private String massege;//消息private Object result;//数据对象/*** 无参构造器*/public Result(){super();}/*** 只返回状态，状态码，消息* @param statu* @param code* @param massege*/public Result(Boolean success, Integer code, String massege){super();this.isSuccess=success;this.code=code;this.massege=massege;}/*** 只返回状态，状态码，数据对象* @param statu* @param code* @param object*/public Result(Boolean success, Integer code, Object result){super();this.isSuccess=success;this.code=code;this.result=result;}/*** 返回全部信息即状态，状态码，消息，数据对象* @param statu* @param code* @param massege* @param result*/public Result(Boolean success, Integer code, String massege, Object result){super();this.isSuccess=success;this.code=code;this.massege=massege;this.result=result;}public Integer getCode() {return code;}public void setCode(Integer code) {this.code = code;}public Boolean getIsSuccess() {return isSuccess;}public void setIsSuccess(Boolean isSuccess) {this.isSuccess = isSuccess;}public String getMassege() {return massege;}public void setMassege(String massege) {this.massege = massege;}public Object getResult() {return result;}public void setResult(Object result) {this.result = result;}}

Result实体创建了接下来还需要把转换为json,我这里用的fastJson，这方面的资料网上很多，下面看下Json这个类，

package com.steven.utils.json;import java.io.PrintWriter;import javax.servlet.http.HttpServletResponse;import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.steven.utils.result.Result;/*** 抛出json数据格式* @author QHY**/
public class Json {public static void toJson(Result result, HttpServletResponse response) throws Exception{response.setContentType("text/json");response.setHeader("Cache-Control", "no-cache");response.setCharacterEncoding("UTF-8");PrintWriter writer = response.getWriter();String json = JSONObject.toJSONString(result, SerializerFeature.WriteMapNullValue,SerializerFeature.WriteNullNumberAsZero,SerializerFeature.WriteNullListAsEmpty,SerializerFeature.WriteNullStringAsEmpty,SerializerFeature.WriteNullBooleanAsFalse,SerializerFeature.DisableCircularReferenceDetect);writer.write(json);   	writer.close();}
}

最后就是测试代码了UserController,

/*** 查询所有用户* @throws Exception*/@RequestMapping(value="/user/findAll.htm",method=RequestMethod.GET)public void findAll(HttpServletResponse response) throws Exception{List<User> list = userService.findAll(); if(list.isEmpty()){Json.toJson(new Result(false,7000,"没有数据",null),response);return;}List<User> listuser = new ArrayList<User>();for (User entity : list) {User user = new User();user.setAdd_time(entity.getAdd_time());user.setDelete_status(entity.getDelete_status());user.setId(entity.getId());user.setLast_login_time(entity.getLast_login_time());user.setName(entity.getName());user.setPwd(entity.getPwd());listuser.add(entity);}Result result = new Result(true,200,"成功",listuser);Json.toJson(result,response);}

最后显示结果

{"code": 200,"isSuccess": true,"massege": "成功","result": [{"add_time": 1521368553000,"delete_status": false,"id": 3,"last_login_time": 1521368553000,"name": "李四","pwd": "123456"}]}