[英]How to change JsonObject in JsonArray?
我正在使用javax.json
並且當我嘗試在我的jsonArray
更改jsonObject
時:
String jsonString = "[{\"name\":\"xyz\"," +
"\"URL\":\"http://example.com\"}]";
JsonReader jsonReader = Json.createReader(new StringReader(jsonString));
JsonArray jsonArray = jsonReader.readArray();
String jsonNewString = "{\"name\":\"zyx\","
+ "\"URL\":\"http://example2.com\"}]";
jsonReader = Json.createReader(new StringReader(jsonNewString));
JsonObject jsonObject = jsonReader.readObject();
jsonReader.close();
jsonArray.remove(0);
jsonArray.add(0, jsonObject);
我得到了這個例外:
java.lang.UnsupportedOperationException
at java.util.AbstractList.remove(AbstractList.java:161)
我也試過: jsonArray.set(0, jsonObject);
,並得到相同的UnsupportedOperationException
。
JsonObject 和 JsonArray 是不可變的,因此您無法修改對象,您可以使用此示例並嘗試從中獲得啟發:
創建一個包含相同值的新 JsonObject 並向其中添加一些元素..
例子 :
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import javax.json.Json;
import javax.json.JsonArray;
import javax.json.JsonArrayBuilder;
import javax.json.JsonObject;
import javax.json.JsonObjectBuilder;
import javax.json.JsonReader;
import javax.json.JsonValue;
public class Jsonizer {
public static void main(String[] args) {
try {
String s = "{\"persons\": [ {\"name\":\"oussama\",\"age\":\"30\"}, {\"name\":\"amine\",\"age\":\"25\"} ]}";
InputStream is = new ByteArrayInputStream(s.getBytes());
JsonReader jr = Json.createReader(is);
JsonObject jo = jr.readObject();
System.out.println("Before :");
System.out.println(jo);
JsonArray ja = jo.getJsonArray("persons");
InputStream targetStream = new ByteArrayInputStream("{\"name\":\"sami\",\"age\":\"50\"}".getBytes());
jr = Json.createReader(targetStream);
JsonObject newJo = jr.readObject();
JsonArrayBuilder jsonArraybuilder = Json.createArrayBuilder();
jsonArraybuilder.add(newJo);
for (JsonValue jValue : ja) {
jsonArraybuilder.add(jValue);
}
ja = jsonArraybuilder.build();
JsonObjectBuilder jsonObjectBuilder = Json.createObjectBuilder();
jsonObjectBuilder.add("persons", ja);
JsonObject jsonAfterAdd = jsonObjectBuilder.build();
System.out.println("After");
System.out.println(jsonAfterAdd.toString());
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
輸出 :
Before :
{"persons":[{"name":"oussama","age":"30"},{"name":"amine","age":"25"}]}
After
{"persons":[{"name":"sami","age":"50"},{"name":"oussama","age":"30"},{"name":"amine","age":"25"}]}
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