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。 |
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; } } |
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; } } |
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); } } |
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> |
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"}