object轉爲有序json

一、引入依賴

<dependency>
	<groupId>com.google.code.gson</groupId>
	<artifactId>gson</artifactId>
	<version>2.8.2</version>
</dependency>

二、實現

import java.util.Comparator;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.TreeMap;

import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;

/** 
 * 排序工具
 * @ClassName: SortUtils 
 * @Description: 
 * @author weiyb 
 */
public class SortUtils{

	/**
	 * 獲取有序字符串
	 * @param object
	 * @return
	 * @author weiyb
	 */
	public static String getSortParamsByObject(Object object) {
		Gson g = new Gson();
		JsonElement e = g.toJsonTree(object);
		sort(e);
		return g.toJson(e);
	}

	private static Comparator<String> getComparator() {
		Comparator<String> c = new Comparator<String>() {
			public int compare(String o1, String o2) {
				return o1.compareTo(o2);
			}
		};
		return c;
	}

	public static void sort(JsonElement e) {
		if (e.isJsonNull()) {
			return;
		}

		if (e.isJsonPrimitive()) {
			return;
		}

		if (e.isJsonArray()) {
			JsonArray a = e.getAsJsonArray();
			for (Iterator<JsonElement> it = a.iterator(); it.hasNext();) {
				sort(it.next());
			}
			return;
		}

		if (e.isJsonObject()) {
			Map<String, JsonElement> tm = new TreeMap<String, JsonElement>(getComparator());
			for (Entry<String, JsonElement> en : e.getAsJsonObject().entrySet()) {
				tm.put(en.getKey(), en.getValue());
			}

			for (Entry<String, JsonElement> en : tm.entrySet()) {
				e.getAsJsonObject().remove(en.getKey());
				e.getAsJsonObject().add(en.getKey(), en.getValue());
				sort(en.getValue());
			}
			return;
		}
	}
}

三、測試

import org.junit.Test;

import com.alibaba.fastjson.JSON;

/**
 * @ClassName: SignTest
 * @Description:
 * @author weiyb
 * @date 2018年4月10日 下午8:24:30
 */
public class SortTest {
	
	@Test
	public void sortTest() {
		User user=new User("1","張三",12);
		String content = SortUtils.getSortParamsByObject(user);
		System.out.println(JSON.toJSONString(content));
	}
}
class User{
	private String id;
	private String name;
	private int age;
	public User(String id, String name, int age) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
	}
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	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;
	}
}