java转JSON串的几种方式

ゞ浴缸里的玫瑰 2022-06-05 10:37 184阅读 0赞

昨天在与对端系统调接口的时候，对端系统对我们传过去的json串老是处理不了，后来查原因是应为我们传过去的json串里有json对象数组，因为我们的json串存在表里的，取出来是作为json字符串放到json数组里的，所以带了双引号，对端认为是字符串，不是json对象所以处理不了。\[\{"cardName":"bankCard1","cardCode":"888888888","cardValue":99999999\},\{"cardName":"bankCard2","cardCode":"999999999","cardValue":222222222\}\] 这种是正确的json对象数组，\["\{"cardName":"bankCard1","cardCode":"888888888","cardValue":99999999\}","\{"cardName":"bankCard2","cardCode":"999999999","cardValue":222222222\}"\]，这种是json字符串数组。

以下总结一下java转JSON串的几种方式：

1、将java对象转成json串

2、通过JSONObject生成json串

3、通过json字符串生成json串

代码通过阿里的fastjson包实现。

代码如下：

1、Person类，包含Crad的List

package com.doit8.test.jsontest.pojo;
    
    import java.util.ArrayList;
    import java.util.List;
    
    public class Person {
    	private String username;
    	private String email;
    	private String sex;
    	private int age;
    	private List<Card> cardList=new ArrayList<Card>();
    	
    	public String getUsername() {
    		return username;
    	}
    	public void setUsername(String username) {
    		this.username = username;
    	}
    	public String getEmail() {
    		return email;
    	}
    	public void setEmail(String email) {
    		this.email = email;
    	}
    	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;
    	}
    	public List<Card> getCardList() {
    		return cardList;
    	}
    	public void setCardList(List<Card> cardList) {
    		this.cardList = cardList;
    	}
    
    }

2、Card类

package com.doit8.test.jsontest.pojo;
    
    public class Card {
    	private String cardName;
    	private String cardCode;
    	private Integer cardValue;
    	public String getCardName() {
    		return cardName;
    	}
    	public void setCardName(String cardName) {
    		this.cardName = cardName;
    	}
    	public String getCardCode() {
    		return cardCode;
    	}
    	public void setCardCode(String cardCode) {
    		this.cardCode = cardCode;
    	}
    	public Integer getCardValue() {
    		return cardValue;
    	}
    	public void setCardValue(Integer cardValue) {
    		this.cardValue = cardValue;
    	}
    }

3、JSON处理测试类

package com.doit8.test.jsontest;
    
    import java.util.ArrayList;
    import java.util.List;
    
    import com.alibaba.fastjson.JSON;
    import com.alibaba.fastjson.JSONArray;
    import com.alibaba.fastjson.JSONObject;
    import com.doit8.test.jsontest.pojo.Card;
    import com.doit8.test.jsontest.pojo.Person;
    
    /**
     * JSON转换
     *
     */
    public class App 
    {
        public static void main( String[] args )
        {
        	//1。通过对象生成JSON串，对象里包含对象数组转成JSON串。
        	Person person=new Person();
        	person.setUsername("xiejava");
        	person.setSex("man");
        	person.setAge(38);
        	person.setEmail("xiejava@ishareread.com");
        	Card card1=new Card();
        	card1.setCardName("bankCard1");
        	card1.setCardCode("888888888");
        	card1.setCardValue(99999999);
        	Card card2=new Card();
        	card2.setCardName("bankCard1");
        	card2.setCardCode("999999999");
        	card2.setCardValue(222222222);
        	//对象数组
        	List<Card> cards=new ArrayList<Card>();
        	cards.add(card1);
        	cards.add(card2);
        	person.setCardList(cards);
        	String json = JSON.toJSON(person).toString();
            System.out.println(json);
        	
            //2.通过JSON对象生成JSON串
        	JSONObject jObject=new JSONObject();
        	jObject.put("username", "xiejava");
        	jObject.put("sex", "man");
        	jObject.put("age", 38);
        	jObject.put("email", "xiejava@ishareread.com");
        	//通过JSONArray包装对象数组
        	JSONArray jArray=new JSONArray();
        	jArray.addAll(cards);
        	jObject.put("cardList", jArray);
        	String json2=jObject.toJSONString();
            System.out.println(json2);
            
            
            //3.通过JSON对象生成JSON串
        	JSONObject jObject2=new JSONObject();
        	jObject2.put("username", "xiejava");
        	jObject2.put("sex", "man");
        	jObject2.put("age", 38);
        	jObject2.put("email", "xiejava@ishareread.com");
        	//构造JSON字符串
        	String cardjsonStr1="{\"cardName\":\"bankCard1\",\"cardCode\":\"888888888\",\"cardValue\":99999999}";
        	String cardjsonStr2="{\"cardName\":\"bankCard2\",\"cardCode\":\"999999999\",\"cardValue\":222222222}";
        	JSON.parseObject(cardjsonStr1);
        	JSONArray jArray2=new JSONArray();
        	//将JSON字符串转成JSON对象，加入到JSONArray，[注意一定要用JSON.parseObject()方法转换成JSON对象，否则还是字符串，转成JSON串的时候会带双引号。]
        	jArray2.add(JSON.parseObject(cardjsonStr1));
        	jArray2.add(JSON.parseObject(cardjsonStr2));
        	jObject2.put("cardList", jArray2);
        	String json3=jObject2.toJSONString();
        	System.out.println(json3);
        	
        	
        }
    }

pom.xml中引入fastjson包

<dependency>
    		<groupId>com.alibaba</groupId>
    		<artifactId>fastjson</artifactId>
    		<version>1.2.15</version>
    	</dependency>

运行结果

{"cardList":[{"cardName":"bankCard1","cardCode":"888888888","cardValue":99999999},{"cardName":"bankCard1","cardCode":"999999999","cardValue":222222222}],"sex":"man","age":38,"email":"xiejava@ishareread.com","username":"xiejava"}
    {"cardList":[{"cardCode":"888888888","cardName":"bankCard1","cardValue":99999999},{"cardCode":"999999999","cardName":"bankCard1","cardValue":222222222}],"sex":"man","age":38,"email":"xiejava@ishareread.com","username":"xiejava"}
    {"cardList":[{"cardName":"bankCard1","cardCode":"888888888","cardValue":99999999},{"cardName":"bankCard2","cardCode":"999999999","cardValue":222222222}],"sex":"man","age":38,"email":"xiejava@ishareread.com","username":"xiejava"}

代码示例 [点击打开链接][Link 1]

[Link 1]: http://download.csdn.net/download/fullbug/10132114