常见的gson的使用方法与fastJson的对比

港控/mmm° 2023-02-20 12:13 17阅读 0赞

fastJson 是我们很常用Json转化使用的依赖，但是fastJson经常报漏洞。在github也有很问题，并没有得到及时的解决。可能需要fastJson切换成其他json的工具。这里将fastJson和gson常用一下方法做一下对比。让只熟悉fastJson更容易切换Gson.

这里采用fastJson 2.6.2 和gson 2.2.4 做对比进行切换

<dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>1.2.62</version>
            </dependency>
            
            <dependency>
                <groupId>com.google.code.gson</groupId>
                <artifactId>gson</artifactId>
                <version>2.2.4</version>
            </dependency>

测试依赖：

//gson 转化为对应
        @Test
        public void testConvertSpecialObject(){
            TimeVO timeVO = new TimeVO();
            timeVO.setStartTime("2020-06-25");
            timeVO.setEndTime("2020-06-26");
            timeVO.setTimestamp(1224343L);
    
            List<String> list = new ArrayList<>();
            list.add("123");
            list.add("456");
            timeVO.setList(list);
    
            //1、将Object转化json对象
            String fastJsonStr = JSON.toJSONString(timeVO);
            Gson gson = new Gson();
            String gsonStr = gson.toJson(timeVO);
    
            System.out.println("fastJsonStr is :"+fastJsonStr+" , gsonStr is :"+gsonStr);
    
    
    
            //2、将json字符串转化为对应对象
            TimeVO fastTimeVO = JSON.parseObject(fastJsonStr, new TypeReference<TimeVO>() {
            });
            TimeVO gsonTimeVO = gson.fromJson(gsonStr, TimeVO.class);
            //或者
            TimeVO gsonTimeVO2 = gson.fromJson(gsonStr, new TypeToken<TimeVO>(){}.getType());
    
            System.out.println("fastTimeVO is " + fastTimeVO + ", gsonVO is " + gsonTimeVO);
    
    
    
    
    
            //3、将字符串JsonObject 对象,在获取对应属性
          
            JSONObject fastJsonObject = JSON.parseObject(fastJsonStr);
            String fastStartTime = fastJsonObject.getString("startTime");
            Long fastTimeStamp = fastJsonObject.getLong("timeStamp");
            String listStr = fastJsonObject.getString("list");
            List<String> fastList1 = JSONObject.parseArray(listStr, String.class);
            //或者
            List<String> fastList2 = JSONObject.parseArray(fastJsonObject.getJSONArray("list").toJSONString(), String.class);
    
    
            JsonParser jsonParser = new JsonParser();
            JsonObject jsonObject = jsonParser.parse(gsonStr).getAsJsonObject();
            String gsonStartTime  = jsonObject.get("startTime").getAsString();
            //没有Long的包装类型，默认为0
            long gsonTimeStamp = jsonObject.get("timestamp").getAsLong();
            //这里需要注意 fastJson 可以直接获取成string ，在转化list
            //gson必须直接获取jsonArray
            JsonArray list1 = jsonObject.get("list").getAsJsonArray();
            List gsonList = gson.fromJson(list1, new TypeToken<List<String>>() {
            }.getType());
    
    
    
    
            //4、借助jsonObject 放置参数
            JSONObject jsonObject1 = new JSONObject();
            jsonObject1.put("key1", "value1");
            jsonObject1.put("key2", 10L);
            String fastJson = jsonObject1.toJSONString();
            System.out.println(fastJson);
    
            HashMap<String, Object> tempMap = new HashMap<>();
            tempMap.put("key1", "value1");
            tempMap.put("key2", 10L);
            String mapJson = gson.toJson(tempMap);
            System.out.println(mapJson);
        }
    }

![在这里插入图片描述][20200626183847219.png]

@Test
        public void test2(){
    
            String str = "{\"endTime\":\"2020-06-26\",\"startTime\":\"2020-06-25\",\"timestamp\":0,\"list\":null}";
    
            JSONObject jsonObject = JSONObject.parseObject(str);
            JSONArray fastArray = jsonObject.getJSONArray("list");
            if(Objects.isNull(fastArray)){
                System.out.println("fastArray is null");
            }else {
                List<String> fastList = JSON.parseArray(fastArray.toJSONString(), String.class);
                System.out.println(fastList);
            }
    
            JsonParser jsonParser = new JsonParser();
            JsonElement jsonElement = jsonParser.parse(str).getAsJsonObject().get("list");
            if (Objects.isNull(jsonElement) || JsonNull.INSTANCE.equals(jsonElement)) {
                System.out.println("jsonElement is null");
            }else {
                Gson gson = new Gson();
                JsonArray jsonArray = jsonElement.getAsJsonArray();
                String s = gson.fromJson(jsonArray, new TypeToken<List<String>>() {
                }.getType());
                System.out.println(s);
            }
    
        }

![在这里插入图片描述][20200629231636234.png]

这里需要特别注意是jsonElement的判断为空为

if (Objects.isNull(jsonElement) || JsonNull.INSTANCE.equals(jsonElement)) {

此时的jsonElement 并不为null,如果将jsonElement的判断为空改为

if (Objects.isNull(jsonElement)) {

则会出现下面异常

java.lang.IllegalStateException: This is not a JSON Array.
    
    	at com.google.gson.JsonElement.getAsJsonArray(JsonElement.java:106)
    	at com.yin.freemakeradd.utils.GsonTest.test2(GsonTest.java:111)
    	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    	at java.lang.reflect.Method.invoke(Method.java:498)
    	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

附上TimeVO类：

@Data
    public class TimeVO {
        private String startTime;
        private String endTime;
        private long timestamp;
        private List<String> list;
    }

[20200626183847219.png]: https://img-blog.csdnimg.cn/20200626183847219.png
[20200629231636234.png]: https://img-blog.csdnimg.cn/20200629231636234.png