java生成json字符串的方法

时间：2022-01-15 20:49:40

例1：将map对象添加一次元素（包括字符串对、数组），转换成json对象一次。

代码：

package com.json;

//这是使用org.json的程序：

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(, ).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);

}

}

运行结果：

{"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网下载：http://www.json.org/java/index.html）

java生成json字符串的方法

例2：list转换成json的三种参数形式。

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"]

    }

}

运行结果：

[true,false,true]

["first","second"]

["json","is","easy"]

例3：json转换成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());

        }

    }

}

运行结果：

apple

orange

name Michael

age

baby [Lucy, Lily]

相关文章