gson：将 null 视为空字符串

Java
import com.Google.gson.Gson;
import com.Google.gson.GsonBuilder;
import com.Google.gson.TypeAdapter;
import com.Google.gson.stream.JSonReader;
import com.Google.gson.stream.JSonWriter;
import Java.io.IOException;
public class GsonNullAsEmptyStringExample {
    public static void mAIn(String[] args) {
        // 创建一个自定义的Gson对象
        Gson gson = new GsonBuilder()
                .registerTypeAdapter(String.class, new NullAsEmptyStringAdapter())
                .create();
        // 将Java对象转换为JSON数据
        String JSon = gson.toJSon(new Person("John", null));
        System.out.println("转换后的JSON数据：" + JSon);
        // 将JSON数据反序列化为Java对象
        Person person = gson.fromJSon(JSon, Person.class);
        System.out.println("反序列化后的Java对象：" + person);
    }
}
class NullAsEmptyStringAdapter extends TypeAdapter<String> {
    @Override
    public void write(JSonWriter out, String value) throws IOException {
        if (value == null) {
            out.value("");
        } else {
            out.value(value);
        }
    }
    @Override
    public String read(JSonReader in) throws IOException {
        return in.nextString();
    }
}
class Person {
    private String name;
    private String address;
    public Person(String name, String address) {
        this.name = name;
        this.address = address;
    }
    // 省略getter和setter方法
    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + ''' +
                ", address='" + address + ''' +
                '}';
    }
}