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Java转JSON串的几种方式

2024-07-14 08:40:50
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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"}


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