java对象与json对象间的相互转换

缺乏、安全感 2022-03-20 06:40 455阅读 0赞

转自：https://blog.csdn.net/harryptter/article/details/54575577

Java单个对象和List对象转换成Json，Json转List 可查看上一篇文章：[https://blog.csdn.net/qq\_36411874/article/details/83114337][https_blog.csdn.net_qq_36411874_article_details_83114337]

**目录**

备注：格式化检测json网址：

备注：导入的jar包

1.简单的解析json字符串

2.将json字符串转换为java对象

3.将java对象转换为json字符串

4，java解析提取json指定节点里面的数组字符串中存入List数组

--------------------

### 备注：格式化检测json网址： ###

[http://www.bejson.com/][http_www.bejson.com]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM2NDExODc0_size_16_color_FFFFFF_t_70][]

### 备注：导入的jar包 ###

import java.util.List;
    
    import org.junit.Test;
    
    import com.suning.api.DefaultSuningClient;
    import com.suning.api.entity.custom.orderGetGetRequest;
    import com.suning.api.entity.custom.orderGetGetResponse;
    import com.suning.api.entity.transaction.OrdercodeQueryRequest;
    import com.suning.api.entity.transaction.OrdercodeQueryResponse;
    import com.suning.api.exception.SuningApiException;
    
    import net.sf.json.JSONArray;
    import net.sf.json.JSONObject;
    import net.sf.json.JsonConfig;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM2NDExODc0_size_16_color_FFFFFF_t_70 1][]

### 1.简单的解析json字符串 ###

首先将json字符串转换为json对象，然后再解析json对象，过程如下。

JSONObject jsonObject = JSONObject.fromObject(jsonStr);

根据json中的键得到它的值

String name = jsonObject.getString("name");  
int num = jsonObject.getInt("num");  
String sex = jsonObject.getString("sex");  
int age = jsonObject.getInt("age");

### 2.将json字符串转换为java对象 ###

同样先将json字符串转换为json对象，再将json对象转换为java对象，如下所示。

JSONObject obj = new JSONObject().fromObject(jsonStr);//将json字符串转换为json对象

将json对象转换为java对象

Person jb = (Person)JSONObject.toBean(obj,Person.class);//将建json对象转换为Person对象

### 3.将java对象转换为json字符串 ###

先将java对象转换为json对象，在将json对象转换为json字符串

JSONObject json = JSONObject.fromObject(obj);//将java对象转换为json对象

String str = json.toString();//将json对象转换为字符串

### 4，java解析提取json指定节点里面的数组字符串中存入List数组 ###

\{\\"sn\_responseContent\\":\{\\"sn\_body\\":\{\\"orderCodeQuery\\":\{\\"orderCode\\":\[\\"346\\",\\"333\\",\\"364\\",\\"361\\",\\"361\\",\\"323\\",\\"394\\",\\"387\\",\\"324\\",\\"393\\"\]\}\},\\"sn\_head\\":\{\}\}\}

**第一版本：**

JSONObject orderCodejson= JSONObject.fromObject(orderCodeQuery);//解析最外层orderCode  
 JSONArray jsonArray = orderCodejson.getJSONArray("orderCode");  
 List<String> sList = JSONArray.toList(jsonArray,String.class);（备注，这里的类已经过时，不要用这种，详情往下看第二第三版本）

try {
    		    	JSONObject jsonObject= JSONObject.fromObject(response.getBody());//解析最外层sn_responseContent
    		    	String sn_responseContent = jsonObject.getString("sn_responseContent");
    		    	
    		    	JSONObject sn_bodyjson= JSONObject.fromObject(sn_responseContent);//解析最外层sn_body
    		    	String sn_body = sn_bodyjson.getString("sn_body");//解析外层sn_body
    		    	
    		    	JSONObject orderCodeQueryjson= JSONObject.fromObject(sn_body);//解析最外层
    		    	String orderCodeQuery = orderCodeQueryjson.getString("orderCodeQuery");//解析外层orderCodeQuery
    	
    		    	JSONObject orderCodejson= JSONObject.fromObject(orderCodeQuery);//解析最外层orderCode
    		 
    		    	 JSONArray jsonArray = orderCodejson.getJSONArray("orderCode");
    		    	 List<String> sList = JSONArray.toList(jsonArray,String.class);
    		         for(String s : sList){
    		             System.out.println(s);
    		         }
    
    		    	
    	        }  catch (Exception e) {
    	        	System.out.println("出现异常");
    	            e.printStackTrace();
    	        }

**第二版本：**

用单元测试，代码如下。看起来优化简洁了很多。（但是，感觉还是太长太啰嗦，继续优化，看第三版本，改进终极版本）

@Test
    	public void test() {
    		String json = "{\"sn_responseContent\":{\"sn_body\":{\"orderCodeQuery\":{\"orderCode\":[\"346\",\"333\",\"364\",\"361\",\"361\",\"323\",\"394\",\"387\",\"324\",\"393\"]}},\"sn_head\":{}}}";
            JSONObject jsonObject = JSONObject.fromObject(json);
            JSONObject sn_res = jsonObject.getJSONObject("sn_responseContent");
            JSONObject sn_body = sn_res.getJSONObject("sn_body");
            JSONObject query = sn_body.getJSONObject("orderCodeQuery");
            //JSONObject orderCode = query.getJSONObject("orderCode");
            JSONArray jsonArray = query.getJSONArray("orderCode");
    
            //List<String> sList = JSONArray.toList(jsonArray,String.class);//丢弃用法
            List<String> sList = JSONArray.toList(jsonArray,new String(), new JsonConfig());
            for(String s : sList){
                System.out.println(s);
            }
    	}

第三版本：

终极版本，美观而且看起来心旷神怡的版本。

@Test
    	public void test2() {//改进版本
    		String json = "{\"sn_responseContent\":{\"sn_body\":{\"orderCodeQuery\":{\"orderCode\":[\"346\",\"333\",\"364\",\"361\",\"361\",\"323\",\"394\",\"387\",\"324\",\"393\"]}},\"sn_head\":{}}}";
    		JSONObject jsonObject = JSONObject.fromObject(json);
    
            JSONArray jsonArray = jsonObject.getJSONObject("sn_responseContent")
                    .getJSONObject("sn_body")
                    .getJSONObject("orderCodeQuery")
                    .getJSONArray("orderCode");
          
            List<String> sList = JSONArray.toList(jsonArray,new String(), new JsonConfig());
    
            for(String s : sList){
                System.out.println(s);
            }
    	}

完整代码

package baz.parse;
     
    import java.util.ArrayList;
    import java.util.List;
     
    import net.sf.json.JSON;
    import net.sf.json.JSONArray;
    import net.sf.json.JSONObject;
    import net.sf.json.JSONSerializer;
    import baz.bean.Person;
     
    public class ParseJson {
    	
    	private String jsonStr;
    	
    	public ParseJson() {
    		
    	}
    	
    	public ParseJson(String str){
    		this.jsonStr = str;
    	}
    	/**
    	 * 解析json字符串
    	 */
    	public void parse(){
    		JSONObject jsonObject = JSONObject.fromObject(jsonStr);
    		String name = jsonObject.getString("name");
    		int num = jsonObject.getInt("num");
    		String sex = jsonObject.getString("sex");
    		int age = jsonObject.getInt("age");
    		
    		System.out.println(name + " " + num + " " + sex + " " + age);
    	}
    	//将json字符串转换为java对象
    	public Person JSON2Object(){
    		//接收{}对象，此处接收数组对象会有异常
    		if(jsonStr.indexOf("[") != -1){
    			jsonStr = jsonStr.replace("[", "");
    		}
    		if(jsonStr.indexOf("]") != -1){
    			jsonStr = jsonStr.replace("]", "");
    		}
    		JSONObject obj = new JSONObject().fromObject(jsonStr);//将json字符串转换为json对象
    		Person jb = (Person)JSONObject.toBean(obj,Person.class);//将建json对象转换为Person对象
    		return jb;//返回一个Person对象
    	}
    	
     
    }

实体类

package baz.bean;
     
    public class Person {
    	
    	private String name;
    	private int num;
    	private String sex;
    	private int age;
    	
    	public Person() {
    		// TODO Auto-generated constructor stub
    	}
     
    	public Person(String name, int num, String sex, int age) {
    		super();
    		this.name = name;
    		this.num = num;
    		this.sex = sex;
    		this.age = age;
    	}
     
     
     
    	public String getName() {
    		return name;
    	}
     
    	public void setName(String name) {
    		this.name = name;
    	}
     
    	public int getNum() {
    		return num;
    	}
     
    	public void setNum(int num) {
    		this.num = num;
    	}
     
    	public String getSex() {
    		return sex;
    	}
     
    	public void setSex(String sex) {
    		this.sex = sex;
    	}
     
    	public int getAge() {
    		return age;
    	}
     
    	public void setAge(int age) {
    		this.age = age;
    	}
    	
    }

将java对象转换为json字符串

package baz.cons;
     
     
    import net.sf.json.JSONObject;
     
     
    /**
     * 将java对象转换为json字符串
     * @author Administrator
     *
     */
    public class ConsJson {
    	
    	public ConsJson() {
    		// TODO Auto-generated constructor stub
    	}
    	
    	public String Object2Json(Object obj){
    		JSONObject json = JSONObject.fromObject(obj);//将java对象转换为json对象
    		String str = json.toString();//将json对象转换为字符串
    		
    		return str;
    	}
    }

测试类：

package baz.test;
     
    import java.util.List;
     
    import baz.bean.Person;
    import baz.cons.ConsJson;
    import baz.parse.ParseJson;
     
     
    public class Test {
    	public static void main(String[] args) {
    		
    		//将字符串转换为json对象，然后根据建得到相应的值
    		ParseJson pj = new ParseJson("{\"name\":\"gu\",\"num\":123456,\"sex\":\"male\",\"age\":24}");
    		pj.parse();
    		
    		//将一个json字符串转换为java对象
    		Person p = pj.JSON2Object();
    		System.out.println("Name:" + p.getName());
    		System.out.println("Num:" + p.getNum());
    		System.out.println("Sex:" + p.getSex());
    		System.out.println("age:" + p.getAge());
    		
    		//将一个java对象转换为Json字符串
    		Person p1 = new Person("gu1",123,"male",23);
    		ConsJson cj = new ConsJson();
    		String str1 = cj.Object2Json(p1);
    		System.out.println(str1);
    		
    	}
     
    }

[https_blog.csdn.net_qq_36411874_article_details_83114337]: https://blog.csdn.net/qq_36411874/article/details/83114337
[http_www.bejson.com]: http://www.bejson.com/
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