[轉]java生成json字串的方法
阿新 • • 發佈:2021-12-16
例1:將map物件新增一次元素(包括字串對、陣列),轉換成json物件一次。
程式碼:
package com.json; //這是使用org.json的程式:import java.util.HashMap;import java.util.Map; import org.json.JSONException;import org.json.JSONObject; public class jsontest { public static void main(String[] args) throws JSONException {String json = "{'name':'reiz'}";JSONObject jsonObj = new JSONObject(json);String name = jsonObj.getString("name"); System.out.println(jsonObj); jsonObj.put("initial", name.substring(0, 1).toUpperCase()); String[] likes = new String[] { "JavaScript", "Skiing", "Apple Pie" };jsonObj.put("likes", likes); System.out.println(jsonObj); Map<String, String> ingredients = new HashMap <String, String>();ingredients.put("apples", "3kg");ingredients.put("sugar", "1kg");ingredients.put("pastry", "2.4kg");ingredients.put("bestEaten", "outdoors");jsonObj.put("ingredients", ingredients);System.out.println(jsonObj); }}
執行結果:
{"name":"reiz"}{"initial":"R","likes":["JavaScript","Skiing","Apple Pie"],"name":"reiz"}{"ingredients":{"apples":"3kg","pastry":"2.4kg","bestEaten":"outdoors","sugar":"1kg"},"initial":"R","likes":["JavaScript","Skiing","Apple Pie"],"name":"reiz"}
(需要用到的包可在官網下載:http://www.json.org/java/index.html)
例2:list轉換成json的三種引數形式。
import java.util.ArrayList;import java.util.List; import net.sf.json.JSONArray;import net.sf.json.JSONObject; public class listToJson { public static void main(String[] args) { boolean[] boolArray = new boolean[]{true,false,true};JSONArray jsonArray1 = JSONArray.fromObject( boolArray );System.out.println( jsonArray1 );// prints [true,false,true] List list = new ArrayList();list.add( "first" );list.add( "second" );JSONArray jsonArray2 = JSONArray.fromObject( list );System.out.println( jsonArray2 );// prints ["first","second"] JSONArray jsonArray3 = JSONArray.fromObject( "['json','is','easy']" );System.out.println( jsonArray3 );// prints ["json","is","easy"] }}
執行結果:
[true,false,true]["first","second"]["json","is","easy"]
例3:json轉換成list和map。
package com.json; import java.util.Collection;import java.util.Map;import java.util.Map.Entry; import net.sf.json.JSONArray;import net.sf.json.JSONObject; public class jsonToListandMap { public static void main(String[] args) { // TODO Auto-generated method stub String listStr = "[\"apple\",\"orange\"]"; Collection<String> strlist = JSONArray.toCollection(JSONArray.fromObject(listStr)); for (String str : strlist) { System.out.println(str); } String mapStr = "{\"age\":30,\"name\":\"Michael\",\"baby\":[\"Lucy\",\"Lily\"]}"; Map<String, Object> map = (Map) JSONObject.toBean(JSONObject .fromObject(mapStr), Map.class); for (Entry<String, Object> entry : map.entrySet()) { System.out.println(entry.getKey() + " " + entry.getValue()); } } }
執行結果:
appleorangename Michaelage 30baby [Lucy, Lily]
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作者:星辰之力
來源:CNBLOGS
原文:https://www.cnblogs.com/zhujiabin/p/5498555.html
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