How to use Gson function for serialization and deserialization in Java

In Java development, serialization and deserialization are very common operations. Serialization is to convert objects into byte streams, which is very useful for network transmission or persistent storage; deserialization is to convert byte streams into objects for further processing. As a commonly used Java serialization and deserialization library, Gson is also widely used. This article will introduce how to use Gson functions for serialization and deserialization in Java.

1. Prerequisites for using Gson

Before we start to introduce how to use Gson, we need to understand the basic concepts and principles of Gson. Gson is a Java library provided by Google for converting Java objects to JSON strings, or JSON strings to Java objects. Gson can handle a variety of data types (including custom Java classes) and is easy to use and extend. Therefore, using Gson for serialization and deserialization operations requires meeting the following conditions:

1. Understand the basic data types in Java and the definition of Java classes and their properties;
2. Understand JSON The format and structure of strings;
3. Proficient in basic knowledge of Java programming;
4. Have downloaded and installed the Gson library file.

2. Use Gson for serialization

Using Gson for serialization is very simple. You only need to convert the Java object to a JSON string. The following are the basic steps for serialization using Gson:

1. Import the Gson library package, and instantiate a Gson object:

import com.google.gson.Gson;
// 导入Gson库包

Gson gson = new Gson();
// 实例化Gson对象

2. Define the Java class, and Create an instance object of the Java class:

public class Person {
    private String name;
    private int age;
    // 定义Java类

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
    // 定义Java类的构造方法

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
    // 添加Java类的getter和setter方法

}

Person person = new Person("Tom", 20);
// 创建Java类的实例对象

3. Convert the Java object to a JSON string:

String jsonStr = gson.toJson(person);
// 将Java对象转换为JSON字符串

In the above code, convert the instance of the Java class Person To convert the object person into a JSON string, use the toJson() method provided by the Gson library. The parameter of this method is the Java object that needs to be serialized, and the return value is a JSON string.

4. Output JSON string:

System.out.println(jsonStr);
// 输出JSON字符串

Output the JSON string, and we can see the serialized result in the console.

3. Use Gson for deserialization

Using Gson for deserialization is also very simple. You only need to convert the JSON string into a Java object. The following are the basic steps for deserialization using Gson:

1. Import the Gson library package and instantiate a Gson object:

import com.google.gson.Gson;
// 导入Gson库包

Gson gson = new Gson();
// 实例化Gson对象

2. Define the Java class, And create an instance object of the Java class:

public class Person {
    private String name;
    private int age;
    // 定义Java类

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
    // 定义Java类的构造方法

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
    // 添加Java类的getter和setter方法

}

String jsonStr = "{"name":"Tom","age":20}";
// 定义JSON字符串

3. Convert the JSON string to a Java object:

Person person = gson.fromJson(jsonStr, Person.class);
// 将JSON字符串转换为Java对象

In the above code, convert the JSON string jsonStr To convert to an instance object of the Java class Person, use the fromJson() method provided by the Gson library. The first parameter of this method is the JSON string that needs to be deserialized, and the second parameter is the type of the Java class that needs to be deserialized. , the return value is the instance object of the Java class.

4. Output Java object:

System.out.println(person.getName() + ":" + person.getAge());
// 输出Java对象

Output the Java object, and we can see the deserialized result in the console.

Summary:

Gson, as a commonly used Java serialization and deserialization library, is also very widely used. Its main advantages include ease of use and extension, processing of various data types, and output formats. specifications, efficient performance, etc. When we need to perform serialization and deserialization operations in Java, we can choose to use the Gson library for processing. When using the Gson library for serialization and deserialization, you need to follow certain rules: first, you need to import the Gson library package and instantiate a Gson object; then define the Java class that needs to be serialized and deserialized, and instantiate Java Object; finally use the toJson() and fromJson() methods provided by the Gson library to convert the Java object to a JSON string or convert the JSON string to a Java object.

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