JSON encoding and decoding using java

JSON encoding and decoding using java

coding

From Java variables to JSON format encoding process is as follows:

public void testJson() {
    JSONObject object = new JSONObject();
    //string
    object.put("string","string");
    //int
    object.put("int",2);
    //boolean
    object.put("boolean",true);
    //array
    List<Integer> integers = Arrays.asList(1,2,3);
    object.put("list",integers);
    //null
    object.put("null",null);
​
    System.out.println(object);
}

In the above example, first create a JSON object, and then successively adding string, integer, and Boolean array, and finally to print a string.

Output:

{"boolean":true,"string":"string","list":[1,2,3],"int":2}

decoding

Variable from Java objects to JSON decoding process is as follows:

Examples

public void testJson2() {
​
  JSONObject object = JSONObject
      .parseObject("{\"boolean\":true,\"string\":\"string\",\"list\":[1,2,3],\"int\":2}");
  String s = object.getString("string");//string
  System.out.println(s);
  int i = object.getIntValue("int");  //int
  System.out.println(i);
  boolean b = object.getBooleanValue("boolean");  //boolean
  System.out.println(b);
  List<Integer> integers = JSON.parseArray(object.getJSONArray("list").toJSONString(),Integer.class);  //list
  integers.forEach(System.out::println);
  System.out.println(object.getString("null"));  //null
​
}

In the above example, the first constructed in a JSON-formatted string JSON object, then sequentially read a string, integer, Boolean, and array, respectively, the final print.

Print results are as follows:

string
2
true
1
2
3
null

JSON object string mutual conversion

method	effect
JSON.parseObject()	Parsing JSON object from a string
JSON.parseArray()	From the array of string parsing JSON
JSON.toJSONString(obj/array)	The JSON object into a string or array of JSON