昨天在與對端系統調接口的時候，對端系統對我們傳過去的json串老是處理不了，後來查原因是應為我們傳過去的json串裡有json對像數組，因為我們的json串存在表裡的，取出來是作為json字符串放到json數組裡的，所以帶了雙引號，對端認為是字符串，不是json對象所以處理不了。
[{"cardName":"bankCard1","cardCode":"888888888","cardValue":99999999},{"cardName":"bankCard2","cardCode":"999999999","cardValue":222222222}] 這種是正確的json對像數組，["{"cardName":"bankCard1","cardCode":"888888888","cardValue":99999999}","{"cardName":"bankCard2","cardCode":"999999999","cardValue":222222222}"]，這種是json字符串數組。以下總結一下java轉JSON串的幾種方式：
1、將java對象轉成json串
2、通過JSONObject生成json串
3、通過json字符串生成json串
代碼通過阿里的fastjson包實現。
代碼如下：
1、Person類，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類
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處理測試類
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轉換* */ public class App { public static void main( String[] args ) { //1。通過對像生成JSON串，對象裡包含對像數組轉成JSON串。 Person person=new Person(); person.setUsername("xiejava"); person.setSex("man"); person.setAge(38); person.setEmail("[email protected]"); 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); //對像數組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.通過JSON對像生成JSON串JSONObject jObject=new JSONObject(); jObject.put("username", "xiejava"); jObject.put("sex", "man"); jObject.put("age", 38); jObject.put("email", "[email protected]"); //通過JSONArray包裝對像數組JSONArray jArray=new JSONArray(); jArray.addAll(cards); jObject.put("cardList", jArray); String json2=jObject.toJSONString(); System.out.println(json2); //3.通過JSON對像生成JSON串JSONObject jObject2=new JSONObject(); jObject2.put("username", "xiejava"); jObject2.put("sex", "man"); jObject2.put("age", 38); jObject2.put("email", "[email protected]"); //構造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(); //將JSON字符串轉成JSON對象，加入到JSONArray，[注意一定要用JSON.parseObject()方法轉換成JSON對象，否則還是字符串，轉成JSON串的時候會帶雙引號。 ] 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>
運行結果
{"cardList":[{"cardName":"bankCard1","cardCode":"888888888","cardValue":99999999},{"cardName":"bankCard1","cardCode":"999999999","cardValue":222222222}],"sex":"man","age":38,"email":"[email protected]","username":"xiejava"}
{"cardList":[{"cardCode":"888888888","cardName":"bankCard1","cardValue":99999999},{"cardCode":"999999999","cardName":"bankCard1","cardValue":222222222}],"sex":"man","age":38,"email":"[email protected]","username":"xiejava"}
{"cardList":[{"cardName":"bankCard1","cardCode":"888888888","cardValue":99999999},{"cardName":"bankCard2","cardCode":"999999999","cardValue":222222222}],"sex":"man","age":38,"email":"[email protected]","username":"xiejava"}