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。
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[{ "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。
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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
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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;
}
}
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2、Card类
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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;
}
}
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3、JSON处理测试类
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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);
}
}
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pom.xml中引入fastjson包
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<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version> 1.2 . 15 </version>
</dependency>
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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"}