详解java生成json字符串的方法

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(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);
 
 
}
}

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：）

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 30

baby [lucy, lily]

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。