Tutorial on converting data into json encoding format using java

It is a lightweight data storage and transmission language.

Json-related packages need to be introduced in java, and the packaging method can be implemented under the lib of the project.

JSON and JAVA Data conversion (JSON is JavaScript Object Natation, which is a lightweight data exchange format, not

It is often suitable for data interaction between servers and JavaScript)

The json expression is similar to the declaration method of the original JavaScript class.

The code is as follows:	Copy code
Var obj = { Name: "javascript ", Age: 20 };

 

Converts java to a json encoding expression;

1. Create a basic json object

Json code

String str = "{}"; // to convert java to json, you must first create the data to be converted.

JSONObject jsonobj = new JSONObject. fromObject (str); // replace java data with json encoding.

2. Use for to loop several numbers into the created json object.

 

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For (int I = 0; I <5; I ++ ){ Jsonobj. put ("json" + I, I); // place java data in a json object // Jsonobj. put ("json" + I, I); the execution result is the same as that of put. // Jsonobj. accumulate ("json" + I, I); the execution result is the same as that of put. System. out. println (jsonobj. toString (); // Print json data  }

 

Json code

Result:

{"Id0": 0}
{"Id0": 0, "id1": 1}
{"Id0": 0, "id1": 1, "id2": 2}
{"Id0": 0, "id1": 1, "id2": 2, "id3": 3}
{"Id0": 0, "id1": 1, "id2": 2, "id3": 3, "id4": 4}

3. put a JSONObject object to json using put.

Json code

 

The code is as follows:	Copy code
For (int I = 0; I <5; I ++ ){ Jsonobj. put ("json" + I, I); // place java data in a json object // Jsonobj. put ("json" + I, I); the execution result is the same as that of put. // Jsonobj. accumulate ("json" + I, I); the execution result is the same as that of put. System. out. println (jsonobj. toString (); // Print json data  }

 

Result:

{"Id0": 0, "id1": 1, "id2": 2, "id3": 3, "id4": 4, "jsonobj": {"date0 ": 0 }}
{"Id0": 0, "id1": 1, "id2": 2, "id3": 3, "id4": 4, "jsonobj": {"date0 ": 0, "date1": 1 }}
{"Id0": 0, "id1": 1, "id2": 2, "id3": 3, "id4": 4, "jsonobj": {"date0 ": 0, "date1": 1, "date2": 2 }}
{"Id0": 0, "id1": 1, "id2": 2, "id3": 3, "id4": 4, "jsonobj": {"date0 ": 0, "date1": 1, "date2": 2, "date3": 3 }}
{"Id0": 0, "id1": 1, "id2": 2, "id3": 3, "id4": 4, "jsonobj": {"date0 ": 0, "date1": 1, "date2": 2, "date3": 3, "date4": 4 }}

4. Add the array to json.

Java code

 

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// Create a basic json object String date = "{}"; JSONObject jsonobj = JSONObject. fromObject (date );   // Use int to place the value in json For (int j = 0; j <5; j ++ ){ // Jsonobj. put ("id" + j, j ); // Jsonobj. accumulate ("id" + j, j ); Jsonobj. element ("id" + j, j ); // System. out. println (jsonobj. toString ()); }

   

 

Result:

{"Arr": ["json", "ajax", "Jquery", "javascript"]}

5. Put the list in json.

Java code

 

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String date = "{}"; JSONObject jsonobj = JSONObject. fromObject (date ); ArrayList <String> list = new ArrayList <String> (); List. add ("json "); List. add ("java "); List. add ("android "); Jsonobj. put ("jsonobj", list ); System. out. println (jsonobj. toString ());

 

Result: {"jsonobj": ["json", "java", "android"]}

6. Put the map in json.

Json code

 

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String date = "{}"; JSONObject jsonobj = JSONObject. fromObject (date); // create the converted object Map <String, Object> map = new HashMap <String, Object> (); // create a map queue Map. put ("map1", "json "); Map. put ("map2", "java "); Map. put ("map3", "android "); Jsonobj. put ("map", map); // put it in json System. out. println (jsonobj. toString ());

 

Result:

{"Map": {"map3": "android", "map2": "java", "map1": "json "}}

7. Put json into the queue using putAll

Json code

 

The code is as follows:	Copy code
String date = "{}"; JSONObject jsonobj = JSONObject. fromObject (date); // create the converted object Map <String, Object> map = new HashMap <String, Object> (); Map. put ("map1", "json "); Map. put ("map2", "android "); Map. put ("map3", "Jquery "); Jsonobj. putAll (map ); System. out. println (jsonobj. toString ());

 

Result:

{"Map3": "Jquery", "map2": "android", "map1": "json "}

8. Differences Between put and putAll:

Put; there will be an object {"map": {"map3": "android", "map2": "java", "map1": "json "}}

PutAll does not {"map3": "Jquery", "map2": "android", "map1": "json "}

9. Combination: (The Returned result value is an array of objects)

Json code

 

The code is as follows:

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// Train of thought: // 1. Create an object converted to json // 2. Create An ArrayList queue to store the converted json object. // 3. Create a json object three times using the for loop and add a value to the json object created in the loop. // 4. Place the json object created in the loop to the queue. // 5. Add the queue to json String date = "{}"; JSONObject jsonobj = JSONObject. fromObject (date); // create the converted object ArrayList <JSONObject> list = new ArrayList <JSONObject> (); // Create a queue For (int I = 0; I <3; I ++) {// Loop JSONObject json = JSONObject. fromObject (date); // converted java Json. put ("aaaa" + I, I ); Json. put ("bbbb" + I, I ); Json. put ("cccc" + I, I ); List. add (json );     }    Jsonobj. put ("succList", list ); System. out. println (jsonobj. toString ());

 

Result:

{"SuccList ":[
{"Aaaa0": 0, "bbbb0": 0, "cccc0": 0 },
{& Quot; aaaa1 & quot;: 1, & quot; bbbb1 & quot;: 1, & quot; ccpc3 & quot;: 1 },
{"Aaaa2": 2, "bbbb2": 2, "cccc2": 2}
]}

10. json combination. The returned result value is an array.

Json code

 

The code is as follows:

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// Create a basic json object String date = "{}"; JSONObject jsonobj = JSONObject. fromObject (date ); String [] str = {"json", "ajax", "Jquery", "javascript"}; // Array Jsonobj. put ("arr", str ); ArrayList <JSONObject> list = new ArrayList <JSONObject> (); // Create a queue For (int I = 0; I <3; I ++) {// Loop JSONObject json = JSONObject. fromObject (date); // converted java Json. put ("aaaa" + I, I ); Json. put ("bbbb" + I, I ); Json. put ("cccc" + I, str); // add an array List. add (json );    }    Jsonobj. put ("succList", list ); System. out. println (jsonobj. toString ());

 

Result:

{"Arr": ["json", "ajax", "Jquery", "javascript"],
"SuccList": [{"aaaa0": 0, "bbbb0": 0, "cccc0": ["json", "ajax", "Jquery ", "javascript"]},
{"Aaaa1": 1, "bbbb1": 1, "ccpc3": ["json", "ajax", "Jquery", "javascript"]},
{"Aaaa2": 2, "bbbb2": 2, "cccc2": ["json", "ajax", "Jquery", "javascript"]}
]}

11. Combination, any nesting;

Json code

 

The code is as follows:

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// Create a basic json object String date = "{}"; JSONObject jsonobj = JSONObject. fromObject (date ); String [] str = {"json", "ajax", "Jquery", "javascript"}; // Array // Convert the json of java to be nested into json JSONObject jsonDemo = JSONObject. fromObject (date ); For (int n = 0; n <3; n ++ ){ JsonDemo. put ("combination" + n, n );     }  ArrayList <JSONObject> list = new ArrayList <JSONObject> (); // Create a queue For (int I = 0; I <3; I ++) {// Loop JSONObject json = JSONObject. fromObject (date); // converted java Json. put ("aaaa" + I, jsonDemo); // nested json Json. put ("bbbb" + I, "java "); Json. put ("cccc" + I, str); // The value is an array. List. add (json );     }    Jsonobj. put ("succList", list ); System. out. println (jsonobj. toString ());

 

Running result:

{"SuccList ":
[{"Aaaa0": {"combination 0": 0, "combination 1": 1, "combination 2": 2 },
"Bbbb0": "java", "cccc0": ["json", "ajax", "Jquery", "javascript"]},
{"Aaaa1": {"combination 0": 0, "combination 1": 1, "combination 2": 2 },
"Bbbb1": "java", "ccpc3": ["json", "ajax", "Jquery", "javascript"]},
{"Aaaa2": {"combination 0": 0, "combination 1": 1, "combination 2": 2 },
"Bbbb2": "java", "cccc2": ["json", "ajax", "Jquery", "javascript"]}
]}