天天看點
傳回

介紹4款json的java類庫及其性能測試

JSON(JavaScript Object Notation) 是一種輕量級的資料交換格式。 易于人閱讀和編寫。同時也易于機器解析和生成。 它基于JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999的一個子集。 JSON采用完全獨立于語言的文本格式，這些特性使JSON成為理想的資料交換語言。

下面介紹四款處理json的java類庫：Json-lib、Gson、Jackson、Fastjson

一、Json-lib

JSON-lib is a java library for transforming beans, maps, collections, java arrays and XML to JSON and back again to beans and DynaBeans. 官網：http://json-lib.sourceforge.net/

maven依賴配置：

<dependency>
     <groupId>net.sf.json-lib</groupId>
     <artifactId>json-lib</artifactId>
     <version>2.4</version>
     <classifier>jdk15</classifier>
</dependency>

示例：

/**
  * 将對象序列化成json字元串
  * @param obj
  * @return
  */
public static String bean2Json(Object obj){
    JSONObject jsonObject=JSONObject.fromObject(obj);
    return jsonObject.toString();
}
    
/**
  * 将json字元串反序列化為對象
  * @param jsonStr
  * @param objClass 反序列化為該類的對象
  * @return
  */
@SuppressWarnings("unchecked")
public static <T> T json2Bean(String jsonStr,Class<T> objClass){
    return (T)JSONObject.toBean(JSONObject.fromObject(jsonStr), objClass);
}

二、Gson

Gson is a Java library that can be used to convert Java Objects into their JSON representation. It can also be used to convert a JSON string to an equivalent Java object. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of.

官網：https://code.google.com/p/google-gson/

maven依賴：

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

示例：

public static String bean2Json(Object obj){
    Gson gson = new GsonBuilder().create();
    return gson.toJson(obj);
}
    
public static <T> T json2Bean(String jsonStr,Class<T> objClass){
    Gson gson = new GsonBuilder().create();
    return gson.fromJson(jsonStr, objClass);
}
    
/**
  * 把混亂的json字元串整理成縮進的json字元串
  * @param uglyJsonStr
  * @return
  */
public static String jsonFormatter(String uglyJsonStr){
    Gson gson = new GsonBuilder().setPrettyPrinting().create();
    JsonParser jp = new JsonParser();
    JsonElement je = jp.parse(uglyJsonStr);
    String prettyJsonString = gson.toJson(je);
    return prettyJsonString;
}

三、Jackson

Jackson is a high-performance JSON processor (parser, generator)。官網：http://jackson.codehaus.org/Home

maven依賴：

<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-mapper-asl</artifactId>
    <version>1.9.13</version>
</dependency>

示例：

public static String bean2Json(Object obj) throws IOException {
    ObjectMapper mapper = new ObjectMapper();
    StringWriter sw = new StringWriter();
    JsonGenerator gen = new JsonFactory().createJsonGenerator(sw);
    mapper.writeValue(gen, obj);
    gen.close();
    return sw.toString();
}

public static <T> T json2Bean(String jsonStr, Class<T> objClass)
        throws JsonParseException, JsonMappingException, IOException {
    ObjectMapper mapper = new ObjectMapper();
    return mapper.readValue(jsonStr, objClass);
}

四、FastJson

Fastjson是一個Java語言編寫的JSON處理器,由阿裡巴巴公司開發。網址：https://github.com/alibaba/fastjson

maven依賴配置：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.1.35</version>
</dependency>

示例：

public static String bean2Json(Object obj){
    return JSON.toJSONString(obj);
}
    
public static <T> T json2Bean(String jsonStr,Class<T> objClass){
    return JSON.parseObject(jsonStr, objClass);
}

五、性能測試

1、Java對象序列化為Json字元串：

執行100 0000次轉換，各個類庫的耗時如下：（以秒為機關）

Gson  48.891s
Json-lib 311.446s
Jackson 19.439s
FastJson 21.706

2、Json字元串 反序列化為Java對象

執行100 0000次轉換，各個類庫的耗時如下：（以秒為機關）

Gson  39.280s
Json-lib

使用該類庫的方法進行轉換時（測試代碼見下面），抛出異常。其原因

是Person類的屬性：List<Person> friends，其List中的對象不是Person

類型的對象，而是net.sf.ezmorph.bean.MorphDynaBean類型的對象。

說明，Json-lib對嵌套的自定義類支援的很差，或許是我寫的方法有問題。
Jackson 26.427s
FastJson 40.556

3、總結：

Java Bean序列化為Json，性能：Jackson > FastJson > Gson > Json-lib。這4中類庫的序列化結構都正确。

Json字元串反序列化為Java Bean時，性能：Jackson > Gson > FastJson >Json-lib。并且Jackson、Gson、FastJson可以很好的支援複雜的嵌套結構定義的類，而Json-lib對于複制的反序列化會出錯。

Jackson、FastJson、Gson類庫各有優點，各有自己的專長，都具有很高的可用性。

4、測試用例

1）Java Bean

public class Person {
    private String name;
    private FullName fullName;
    private int age;
    private Date birthday;
    private List<String> hobbies;
    private Map<String, String> clothes;
    private List<Person> friends;
    
    //getter setter 方法。略

    @Override
    public String toString() {
        String str= "Person [name=" + name + ", fullName=" + fullName + ", age="
                + age + ", birthday=" + birthday + ", hobbies=" + hobbies
                + ", clothes=" + clothes +  "]\n";
        if(friends!=null){
            str+="Friends:\n";
            for (Person f : friends) {
                str+="\t"+f;
            }
        }
        return str;
    }
    
}

class FullName {
    private String firstName;
    private String middleName;
    private String lastName;
    
　　//構造方法、getter setter 方法，略
 　　
    @Override
    public String toString() {
        return "[firstName=" + firstName + ", middleName="
                + middleName + ", lastName=" + lastName + "]";
    }
    
}

2）Json-lib、Gson、Jackson、FastJson類庫：

import net.sf.json.JSONObject;

public class JsonObjectUtil {

    public static String bean2Json(Object obj){
        JSONObject jsonObject=JSONObject.fromObject(obj);
        return jsonObject.toString();
    }
    
    @SuppressWarnings("unchecked")
    public static <T> T json2Bean(String jsonStr,Class<T> objClass){
        return (T)JSONObject.toBean(JSONObject.fromObject(jsonStr), objClass);
    }
    
}
           
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;
import com.google.gson.JsonParser;

public class GsonUtil {
    private static Gson gson = new GsonBuilder().create();
    
    public static String bean2Json(Object obj){
        return gson.toJson(obj);
    }
    
    public static <T> T json2Bean(String jsonStr,Class<T> objClass){
        return gson.fromJson(jsonStr, objClass);
    }
    
    public static String jsonFormatter(String uglyJsonStr){
        Gson gson = new GsonBuilder().setPrettyPrinting().create();
        JsonParser jp = new JsonParser();
        JsonElement je = jp.parse(uglyJsonStr);
        String prettyJsonString = gson.toJson(je);
        return prettyJsonString;
    }
}
           
import java.io.IOException;
import java.io.StringWriter;

import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;

public class JacksonUtil {
    private static ObjectMapper mapper = new ObjectMapper();
    
    public static String bean2Json(Object obj) throws IOException {
        StringWriter sw = new StringWriter();
        JsonGenerator gen = new JsonFactory().createJsonGenerator(sw);
        mapper.writeValue(gen, obj);
        gen.close();
        return sw.toString();
    }

    public static <T> T json2Bean(String jsonStr, Class<T> objClass)
            throws JsonParseException, JsonMappingException, IOException {
        return mapper.readValue(jsonStr, objClass);
    }
}
           
public class FastJsonUtil {
    public static String bean2Json(Object obj){
        return JSON.toJSONString(obj);
    }
    
    public static <T> T json2Bean(String jsonStr,Class<T> objClass){
        return JSON.parseObject(jsonStr, objClass);
    }
}

3）Java對象序列化為Json字元串 測試類：

public class TestBean2Json {
    private Person p;
    
    private Person createAPerson(String name,List<Person> friends) {
        Person newPerson=new Person();
        newPerson.setName(name);
        newPerson.setFullName(new FullName("xxx_first", "xxx_middle", "xxx_last"));
        newPerson.setAge(24);
        List<String> hobbies=new ArrayList<String>();
        hobbies.add("籃球");
        hobbies.add("遊泳");
        hobbies.add("coding");
        newPerson.setHobbies(hobbies);
        Map<String,String> clothes=new HashMap<String, String>();
        clothes.put("coat", "Nike");
        clothes.put("trousers", "adidas");
        clothes.put("shoes", "安踏");
        newPerson.setClothes(clothes);
        newPerson.setFriends(friends);
        return newPerson;
    }
    
    @Before
    public void init(){
        List<Person> friends=new ArrayList<Person>();
        friends.add(createAPerson("小明",null));
        friends.add(createAPerson("Tony",null));
        friends.add(createAPerson("陳小二",null));
         p=createAPerson("邵同學",friends);
    }
    
    @Test
    public void testGsonBean2Json(){
        System.out.println(GsonUtil.bean2Json(p));
        
        for (int i = 0; i < 1000000; i++) {
            GsonUtil.bean2Json(p);
        }
    }
    
    
    @Test
    public void testJsonObjectBean2Json(){
        System.out.println(JsonlibUtil.bean2Json(p));
        
        for (int i = 0; i < 1000000; i++) {
            JsonlibUtil.bean2Json(p);
        }
    }
    
    
    @Test
    public void testJacksonBean2Json() throws Exception{
        System.out.println(JacksonUtil.bean2Json(p));
        
        for (int i = 0; i < 1000000; i++) {
            JacksonUtil.bean2Json(p);
        }
    }
    
    @Test
    public void testFastJsonBean2Json() throws Exception{
        System.out.println(FastJsonUtil.bean2Json(p));
        
        for (int i = 0; i < 1000000; i++) {
            FastJsonUtil.bean2Json(p);
        }
    }
    
}

4）Json字元串 反序列化為Java對象 測試類：

public class TestJson2Bean {
    private String jsonStr;
    
    @Before
    public void init(){
	jsonStr = "{"
		+ "\"name\":\"邵同學\","
		+ "\"fullName\":{\"firstName\":\"xxx_first\",\"middleName\":\"xxx_middle\",\"lastName\":\"xxx_last\"},"
		+ "\"age\":24,\"birthday\":null,\"hobbies\":[\"籃球\",\"遊泳\",\"coding\"],"
		+ "\"clothes\":{\"shoes\":\"安踏\",\"trousers\":\"adidas\",\"coat\":\"Nike\"},"
		+ "\"friends\":"
		+ "["
		+ "{\"name\":\"小明\","
		+ "\"fullName\":{\"firstName\":\"xxx_first\",\"middleName\":\"xxx_middle\",\"lastName\":\"xxx_last\"},"
		+ "\"age\":24,\"birthday\":null,\"hobbies\":[\"籃球\",\"遊泳\",\"coding\"],"
		+ "\"clothes\":{\"shoes\":\"安踏\",\"trousers\":\"adidas\",\"coat\":\"Nike\"},\"friends\":null},"
		+ "{\"name\":\"Tony\","
		+ "\"fullName\":{\"firstName\":\"xxx_first\",\"middleName\":\"xxx_middle\",\"lastName\":\"xxx_last\"},"
		+ "\"age\":24,\"birthday\":null,\"hobbies\":[\"籃球\",\"遊泳\",\"coding\"],"
		+ "\"clothes\":{\"shoes\":\"安踏\",\"trousers\":\"adidas\",\"coat\":\"Nike\"},\"friends\":null},"
		+ "{\"name\":\"陳小二\","
		+ "\"fullName\":{\"firstName\":\"xxx_first\",\"middleName\":\"xxx_middle\",\"lastName\":\"xxx_last\"},"
		+ "\"age\":24,\"birthday\":null,\"hobbies\":[\"籃球\",\"遊泳\",\"coding\"],"
		+ "\"clothes\":{\"shoes\":\"安踏\",\"trousers\":\"adidas\",\"coat\":\"Nike\"},\"friends\":null}]}";
    }
    
    
    @Test
    public void testGsonjson2Bean() throws Exception{
        Person pp=GsonUtil.json2Bean(jsonStr, Person.class);
        System.out.println(pp);
        
        for (int i = 0; i < 1000000; i++) {
            GsonUtil.json2Bean(jsonStr, Person.class);
        }
    }
    
    
    @Test
    public void testJsonlibJson2Bean() throws Exception{
        Person pp=JsonlibUtil.json2Bean(jsonStr, Person.class);
        System.out.println(pp);
        
        for (int i = 0; i < 1000000; i++) {
            JsonlibUtil.json2Bean(jsonStr, Person.class);
        }
    }
    
    
    @Test
    public void testJacksonJson2Bean() throws Exception{
        Person pp=JacksonUtil.json2Bean(jsonStr, Person.class);
        System.out.println(pp);
        
        for (int i = 0; i < 1000000; i++) {
            JacksonUtil.json2Bean(jsonStr, Person.class);
        }
    }
    
    @Test
    public void testFastJsonJson2Bean() throws Exception{
        Person pp=FastJsonUtil.json2Bean(jsonStr, Person.class);
        System.out.println(pp);
        
        for (int i = 0; i < 1000000; i++) {
            FastJsonUtil.json2Bean(jsonStr, Person.class);
        }
    }
}

轉載來源：https://www.cnblogs.com/windlaughing/p/3241776.html

java json json-lib gson Jackson
上一篇: json-lib 與Jackson性能對比
下一篇: 轉載 Jackson 高性能的JSON處理 ObjectMapper

繼續閱讀