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This article will explain in detail how to use toJson and fromJson methods in Gson. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

Introduce dependencies: add to the pom.xml file

The com.google.code.gson gson 2.8.51.toJson () method is a method that implements the transition from java entities to Json-related objects

(1) convert an object to a json string

Gson gson = new Gson (); User user = new User (123, "zy"); String str = gson.toJson (user); System.out.println (str)

The output is

(2) convert map collection to json string

Gson gson1 = new Gson (); Map map= new HashMap (); map.put (11, "zy"); map.put (12, "zz"); String str1 = gson1.toJson (map); System.out.println (str1)

The output is

The 2.fromJson () method to implement the method from Json related objects to java entities

(1) convert json strings to java objects

Gson gson = new Gson (); User user = new User (123, "zy"); / / convert the object to the json string String str = gson.toJson (user); / / then convert the json string to the java object, and get the value User fromJson = gson.fromJson (str, User.class) in the object through the get method; System.out.println (fromJson.getAge () + "." + fromJson.getName ())

The output is

(2) convert json strings to map collections

Gson gson = new Gson (); Map map= new HashMap (); map.put (11, "zy"); map.put (12, "zz"); / / convert the map collection to the json string String str = gson.toJson (map); / / convert the json string to the map collection Type type = new TypeToken () {} .getType (); Map map1 = gson.fromJson (str, type) / / traverse the map collection for (Integer key: map1.keySet ()) {System.out.println ("key=" + key+ "\ tvalue=" + map1.get (key));}

The output is

This is the end of this article on "how to use toJson and fromJson methods in Gson". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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