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 list = userService.findAll(); 
		if(list.isEmpty()){
			Json.toJson(new Result(false,7000,"没有数据",null),response);
			return;
		}
		List listuser = new ArrayList();
		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"
	}]}