How to convert Java objects to a JSON string?

In Java, you can use the Jackson library to convert objects into JSON strings. First, you need to import dependencies for jackson-databind and jackson-core into your project.

Next, the ObjectMapper class can be used to convert objects to JSON strings. Here is a simple example code:

import com.fasterxml.jackson.databind.ObjectMapper;

public class Main {
    public static void main(String[] args) {
        // 创建一个对象
        Person person = new Person("John", 25);

        try {
            // 创建ObjectMapper对象
            ObjectMapper objectMapper = new ObjectMapper();

            // 将对象转换为JSON字符串
            String jsonStr = objectMapper.writeValueAsString(person);
            System.out.println(jsonStr);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

class Person {
    private String name;
    private int age;

    // 构造方法和getter/setter省略

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    // toString()方法用于输出对象信息
    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

Running the above code will output the following JSON string.

{"name":"John","age":25}

These are the basic steps for converting Java objects to JSON strings.