JSON数据转化实体、List（Gson，FastJson，jackson，Json-Lib四种）

目前前后端分离是越来越趋势化了，前后端交互一般都是用json数据格式，前端传一堆json数据过来，我们转化就成了一个问题，下面就根据转化为实体类和List相关做了一个案例：

首先使用的jar版本是：基本用的都是最新的版本：

        
            net.sf.json-lib
            json-lib
            2.2.3
            jdk15
        
        
            com.google.code.gson
            gson
            2.8.5
        
        
            com.alibaba
            fastjson
            1.2.58
        
        
            com.fasterxml.jackson.core
            jackson-core
            2.9.9
        

对比的主类是：

public class JSONCompare {


    public static void main(String[] args) {
        toBean();
        toList();
    }

    private static void toList() {
        String json = "[\n" +
                "    {\n" +
                "        \"id\": \"124545721\",\n" +
                "        \"age\": \"23\",\n" +
                "        \"name\": \"张三\"\n" +
                "    },\n" +
                "    {\n" +
                "        \"id\": \"14545454\",\n" +
                "        \"age\": \"88\",\n" +
                "        \"name\": \"李四\"\n" +
                "    }\n" +
                "]";
        FastJsonUtil.toList(json);
        System.out.println("------------------>>");
        GsonUtil.toList(json);
        System.out.println("------------------>>");
        JacksonUtil.toList(json);
        System.out.println("------------------>>");
        JsonLibUtil.toList(json);
        System.out.println("------------------>>");
    }

    public static void toBean(){
        String json = "{\n" +
                "    \"name\": \"张三\",\n" +
                "    \"id\": \"23\",\n" +
                "    \"startTime\": \"1561904000000\",\n" +
                "    \"endTime\": \"2018-02-01 06:06:06\"\n" +
                "}";


        FastJsonUtil.toBean(json);
        System.out.println("------------------>>");
        GsonUtil.toBean(json);
        System.out.println("------------------>>");
        JsonLibUtil.toBean(json);
        System.out.println("------------------>>");
        JacksonUtil.toBean(json);

        System.out.println("\n\n时间格式都改成yyyy-HH-dd hh:mm:ss----------------->>");
        String json1 = "{\n" +
                "    \"name\": \"张三\",\n" +
                "    \"id\": \"23\",\n" +
                "    \"startTime\": \"2022-02-01 09:09:09\",\n" +
                "    \"endTime\": \"2018-02-01 06:06:06\"\n" +
                "}";
        FastJsonUtil.toBean(json1);
        System.out.println("------------------>>");
        GsonUtil.toBean(json1);
        System.out.println("------------------>>");
        JsonLibUtil.toBean(json1);
        System.out.println("------------------>>");
        JacksonUtil.toBean(json1);


        System.out.println("\n\n参数缺失，并有多余参数加入------------------>>");
        String json2 = "{\n" +
                "    \"name\": \"张三\",\n" +
                "    \"age\": \"23\",\n" +
                "}";
        FastJsonUtil.toBean(json2);
        System.out.println("------------------>>");
        GsonUtil.toBean(json2);
        System.out.println("------------------>>");
        JsonLibUtil.toBean(json2);
        System.out.println("------------------>>");
        JacksonUtil.toBean(json2);
        System.out.println("\n\nList开始------------------>>");
    }

}

调用不同json格式的类最后再展示：先运行一下结果：

时间：470ms使用fastJson转化成实体：Y(name=张三, id=23, startTime=Sun Jun 30 22:13:20 CST 2019, endTime=Thu Feb 01 06:06:06 CST 2018)
------------------>>
使用Gson装化成实体失败：com.google.gson.JsonSyntaxException: 1561904000000
------------------>>
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
时间：519msJsonLib转化成实体：Y(name=张三, id=23, startTime=Mon Jul 01 22:59:12 CST 2019, endTime=Mon Jul 01 22:59:12 CST 2019)
------------------>>
使用Jackson转化成实体失败：com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `java.util.Date` from String "2018-02-01 06:06:06": not a valid representation (error: Failed to parse Date value '2018-02-01 06:06:06': Cannot parse date "2018-02-01 06:06:06": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ', parsing fails (leniency? null))
 at [Source: (String)"{
    "name": "张三",
    "id": "23",
    "startTime": "1561904000000",
    "endTime": "2018-02-01 06:06:06"
}"; line: 5, column: 16] (through reference chain: com.timeblog.common.Y["endTime"])

时间格式都改成yyyy-HH-dd hh:mm:ss----------------->>
时间：0ms使用fastJson转化成实体：Y(name=张三, id=23, startTime=Tue Feb 01 09:09:09 CST 2022, endTime=Thu Feb 01 06:06:06 CST 2018)
------------------>>
时间：3ms使用Gson装化成实体：Y(name=张三, id=23, startTime=Tue Feb 01 09:09:09 CST 2022, endTime=Thu Feb 01 06:06:06 CST 2018)
------------------>>
时间：7msJsonLib转化成实体：Y(name=张三, id=23, startTime=Mon Jul 01 22:59:13 CST 2019, endTime=Mon Jul 01 22:59:13 CST 2019)
------------------>>
使用Jackson转化成实体失败：com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `java.util.Date` from String "2022-02-01 09:09:09": not a valid representation (error: Failed to parse Date value '2022-02-01 09:09:09': Cannot parse date "2022-02-01 09:09:09": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ', parsing fails (leniency? null))
 at [Source: (String)"{
    "name": "张三",
    "id": "23",
    "startTime": "2022-02-01 09:09:09",
    "endTime": "2018-02-01 06:06:06"
}"; line: 4, column: 18] (through reference chain: com.timeblog.common.Y["startTime"])

参数缺失，并有多余参数加入------------------>>
时间：0ms使用fastJson转化成实体：Y(name=张三, id=null, startTime=null, endTime=null)
------------------>>
使用Gson装化成实体失败：com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Expected name at line 4 column 2 path $.null
------------------>>
时间：0msJsonLib转化成实体：Y(name=张三, id=null, startTime=null, endTime=null)
------------------>>
使用Jackson转化成实体失败：com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "age" (class com.timeblog.common.Y), not marked as ignorable (4 known properties: "endTime", "name", "startTime", "id"])
 at [Source: (String)"{
    "name": "张三",
    "age": "23",
}"; line: 3, column: 13] (through reference chain: com.timeblog.common.Y["age"])

List开始------------------>>
时间：5ms使用fastJson转化成List：[X(id=124545721, age=23, name=张三), X(id=14545454, age=88, name=李四)]
------------------>>
时间：7ms使用Gson装化成List：[X(id=124545721, age=23, name=张三), X(id=14545454, age=88, name=李四)]
------------------>>
时间：19ms使用Jackson装化成List：[X(id=124545721, age=23, name=张三), X(id=14545454, age=88, name=李四)]
------------------>>
时间：8msJsonLib转化成List：[X(id=124545721, age=23, name=张三), X(id=14545454, age=88, name=李四)]
------------------>>

 

结论：

（1）、Gson不能转化时间戳为Date类型

（2）、Json-lib会把时间类型赋值为当前时间

（3）、Jackson转化时间类型出错

（4）、Jackson实体类的字段和json字符串中的key要一直，否则出错

（5）、Gson缺失类对应的变量并多出其他数据会报错

（6）、FastJson几乎可以满足这些要求

（7）、转化为List时候FastJson> Gson>JsonLib>Jackson

（8）、Json-lib最近都没有新版本问题很大不建议使用

（9）、如果使用FastJson的时候转成嵌套的实体时：

这样使用：否则里面的X不会转过去，用X获取数据就会报错

A tencentBaseResBean = JSON.parseObject(result,
        new TypeReference>(){});

其他三个可以根据实际情况选择性使用，各有各的优点，如果不怎么在乎性能可以直接使用fastjson，很强大，但是性能肯定有影响的。

其他类源码：

1、FastJsonUtil.java

import java.util.ArrayList;
import java.util.List;

public class JacksonUtil {
    public static void toBean(String json) {
        try {
            Long start = System.currentTimeMillis();
            ObjectMapper mapper = new ObjectMapper();
            Y y = mapper.readValue(json, Y.class);
            Long end = System.currentTimeMillis();
            System.out.println("时间：" + (end - start) + "ms使用Jackson转化成实体：" + y.toString());
        } catch (Exception e) {
            System.out.println("使用Jackson转化成实体失败：" + e);
        }
    }

    public static void toList(String json){
        try{
            Long start = System.currentTimeMillis();
            ObjectMapper mapper = new ObjectMapper();
            JavaType javaType = mapper.getTypeFactory().constructParametricType(ArrayList.class, X.class);
            List list =  mapper.readValue(json, javaType);
            Long end = System.currentTimeMillis();
            System.out.println("时间：" + (end - start) + "ms使用Jackson装化成List：" + list.toString());
        }catch (Exception e){
            System.out.println("使用Jackson装化成List失败：" + e);
        }
    }

}

2、GsonUtil.java

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

import java.util.List;

public class GsonUtil {
    public static void toBean(String json) {
        try {
            Long start = System.currentTimeMillis();
            Gson gson = new Gson();
            Y y = gson.fromJson(json, Y.class);
            Long end = System.currentTimeMillis();
            System.out.println("时间：" + (end - start) + "ms使用Gson装化成实体：" + y.toString());
        } catch (Exception e) {
            System.out.println("使用Gson装化成实体失败：" + e);
        }
    }

    public static void toList(String json){
        try{
            Long start = System.currentTimeMillis();
            Gson gson = new Gson();
            List list = gson.fromJson(json, new TypeToken>() {}.getType());
            Long end = System.currentTimeMillis();
            System.out.println("时间：" + (end - start) + "ms使用Gson装化成List：" + list.toString());
        }catch (Exception e){
            System.out.println("使用Gson装化成List失败：" + e);
        }
    }
}

3、JacksonUtil.java

import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;


import java.util.ArrayList;
import java.util.List;

public class JacksonUtil {
    public static void toBean(String json) {
        try {
            Long start = System.currentTimeMillis();
            ObjectMapper mapper = new ObjectMapper();
            Y y = mapper.readValue(json, Y.class);
            Long end = System.currentTimeMillis();
            System.out.println("时间：" + (end - start) + "ms使用Jackson转化成实体：" + y.toString());
        } catch (Exception e) {
            System.out.println("使用Jackson转化成实体失败：" + e);
        }
    }

    public static void toList(String json){
        try{
            Long start = System.currentTimeMillis();
            ObjectMapper mapper = new ObjectMapper();
            JavaType javaType = mapper.getTypeFactory().constructParametricType(ArrayList.class, X.class);
            List list =  mapper.readValue(json, javaType);
            Long end = System.currentTimeMillis();
            System.out.println("时间：" + (end - start) + "ms使用Jackson装化成List：" + list.toString());
        }catch (Exception e){
            System.out.println("使用Jackson装化成List失败：" + e);
        }
    }

}

4、JsonLibUtil.java

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

import java.util.List;

public class JsonLibUtil {
    public static void toBean(String json) {
        try {
            Long start = System.currentTimeMillis();
            JSONObject jsonObject = JSONObject.fromObject(json);
            Y y = (Y) JSONObject.toBean(jsonObject, Y.class);
            Long end = System.currentTimeMillis();
            System.out.println("时间："+(end - start) +"msJsonLib转化成实体：" + y.toString());
        } catch (Exception e) {

            System.out.println("JsonLib转化成实体失败：" + e);
        }
    }

    public static void toList(String json) {
        try {
            Long start = System.currentTimeMillis();
            List list=(List) JSONArray.toList(JSONArray.fromObject(json), X.class);
            Long end = System.currentTimeMillis();
            System.out.println("时间："+(end - start) +"msJsonLib转化成List：" + list.toString());
        } catch (Exception e) {

            System.out.println("JsonLib转化成List失败：" + e);
        }
    }
}

5、X.java

import lombok.Data;
import lombok.ToString;

@Data
@ToString
public class X {
    private Long id;
    private Integer age;
    private String name;
}

6、Y.java

@Data
@ToString
public class Y {
    private String name;

    private Long id;

    private Date startTime;

    private Date endTime;



}

 

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