无法使用Java的GSON反序列化未知类型的数组

问题是直到运行时才知道数组中包含的数据类型.我创建了一个测试用例来说明我的问题.一切工作正常,直到涉及到数组.

User user1 = new User(1, "one");
User user2 = new User(2, "two");

User [] users = {user1, user2};

Gson gson = new Gson();

// gson processing array of known a type. WORKS FINE
// observe use of brackets [] 
String toJson = gson.toJson(users, User[].class);
User [] newUsers = gson.fromJson(toJson, User[].class);
for(User user : newUsers) {
    System.out.println(user.toString());
}

// gson processing using reflection for single user. WORKS FINE
final Class<?> userType = Class.forName("com.abc.ws.GsonTest$User");
User user3 = new User(3, "three");
toJson = gson.toJson(user3, userType);
Object newUser = gson.fromJson(toJson, userType);
System.out.println(newUser.toString());

// gson processing using reflection for array of users. FAILS.
toJson = gson.toJson(users, WHAT_TO_PASS_HERE?); // it should be something like: userType[].class but that won't compile
Object newerUsers = gson.fromJson(toJson, WHAT_TO_PASS_HERE?); // it should be something like: userType[].class but that won't compile
for(User user : newerUsers) {
    System.out.println(user.toString());
}

顺便说一句:下面是完整的代码.

package com.abc;


import com.google.gson.Gson;


public class GsonTest {
    public static void main(String[] args) throws Exception {
        GsonTest.go();
}

    public static void go() throws Exception {
        User user1 = new User(1, "one");
        User user2 = new User(2, "two");

        User [] users = {user1, user2};

        Gson gson = new Gson();

        // gson processing array of known a type. Works fine
        // observe use of brackets [] 
        String toJson = gson.toJson(users, User[].class);
        User [] newUsers = gson.fromJson(toJson, User[].class);
        for(User user : newUsers) {
            System.out.println(user.toString());
        }

        // gson processing using reflection for single user. Works fine.
        final Class<?> userType = Class.forName("com.abc.GsonTest$User");
        User user3 = new User(3, "three");
        toJson = gson.toJson(user3, userType);
        Object newUser = gson.fromJson(toJson, userType);
        System.out.println(newUser.toString());

        // gson processing using reflection for array of users. Fails.

        toJson = gson.toJson(users, WHAT_TO_PASS_HERE?); // it should be something like: userType[].class but that won't compile
        Object newerUsers = gson.fromJson(toJson, WHAT_TO_PASS_HERE?); // it should be something like: userType[].class but that won't compile
        for(User user : newerUsers) {
            System.out.println(user.toString());
        }
    }

    public static class User {
        private int id;
        private String name;

        public User() { }

        public User(int id, String name) {
            this.id = id;
            this.name = name;
        }

        public int getId() {
            return id;
        }

        public void setId(int id) {
            this.id = id;
        }

        public String getName() {
            return name;
        }

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

        public String toString() {
            return "id: " + this.id + ", name: " + this.name;
        }
    }
}
最佳答案
尝试通过

Array.newInstance(userType, 0).getClass()

转载注明原文:无法使用Java的GSON反序列化未知类型的数组 - 代码日志