fastjson初始化对性能的影响

之前在项目中序列化是用thrift，性能一般，而且需要用编译器生成新的类，在序列化和反序列化的时候感觉很繁琐，因此想转到json阵营。对比了jackson，gson等框架之后，决定用fastjson，为什么呢，因为看名字感觉很快。。。

 

网上的说法：

 

fastjson 是一个性能很好的 Java 语言实现的 JSON 解析器和生成器，来自阿里巴巴的工程师开发。

主要特点：

快速FAST (比其它任何基于Java的解析器和生成器更快，包括jackson）
强大（支持普通JDK类包括任意Java Bean Class、Collection、Map、Date或enum）
零依赖（没有依赖其它任何类库除了JDK）

 

但是测试的结果让我大跌眼镜。

 

Test Case: 对一个User类（空）的对象分别用java和fastjson序列化1000次，再反序列化1000次，计算时间。注： 测试不是非常严谨，只是做个简单的比较。

 

Test Result： 

 

Type = java
Serialize cost = 27ms
Deserialize cost = 75ms

Type = fastjson
Serialize cost = 385ms
Deserialize cost = 84ms

 

这是在逗我吗。。。

 

经过同事提醒，看了源码发现fastjson在序列化时需要初始化SerializeConfig，反序列化时需要初始化ParserConfig。然后我在测试案例中加入这两句

 

public static ParserConfig pc = new ParserConfig();
public static SerializeConfig sc = new SerializeConfig();

 

果然快了很多，但仍旧不理想

 

Type = fastjson
Serialize cost = 36ms
Deserialize cost = 42ms

 

再继续看，发现还需要初始化writer和parser，所以改成这句

JSON.parseObject(JSON.toJSONString(new User()), User.class);

 

结果就很令人满意了

 

Type = fastjson
Serialize cost = 15ms
Deserialize cost = 18ms

 

 

结论： 如果你使用fastjson在一个短进程，换句话说只是少量的进行序列化反序列化，那么fastjson由于初始化需要的时间比较长，总体性能将会很糟糕。如果一定要用，有必要的话可以考虑手动进行初始化。

 

另，补上测试代码：

class User implements Serializable {
	private static final long serialVersionUID = -2513747641863637392L;

	User() {
	}
}

public class Test {
//	public static ParserConfig pc = new ParserConfig();
//	public static SerializeConfig sc = new SerializeConfig();

	public static void main(String[] args) throws UnknownHostException {
//		JSON.parseObject(JSON.toJSONString(new User()), User.class);
		String type = "json";
		System.out.println("Type = " + type);
		long start = new Date().getTime();
		byte[] b = serialize(new User(), type);
		long mid = new Date().getTime();
		System.out.println("Serialize cost = " + (mid - start));
		deserialize(b, type);
		System.out.println("Deserialize cost = " + (new Date().getTime() - mid));
	}

	public static byte[] serialize(User user, String type) {
		byte[] b = null;
		for (int i = 0; i < 1000; i++) {
			if ("java".equalsIgnoreCase(type)) {
				b = javaSerialize(user);
			} else if ("json".equalsIgnoreCase(type)) {
				b = jsonSerialize(user);
			}
		}
		return b;
	}

	public static User deserialize(byte[] b, String type) {
		User user = null;
		for (int i = 0; i < 1000; i++) {
			if ("java".equalsIgnoreCase(type)) {
				user = javaDeserialize(b);
			} else if ("json".equalsIgnoreCase(type)) {
				user = jsonDeserialize(b);
			}
		}
		return user;
	}

	public static byte[] jsonSerialize(User user) {
		return JSON.toJSONString(user).getBytes();
	}

	public static User jsonDeserialize(byte[] b) {
		return JSON.parseObject(new String(b), User.class);
	}

	public static byte[] javaSerialize(User user) {
		try {
			ByteArrayOutputStream out = new ByteArrayOutputStream();
			ObjectOutputStream os = new ObjectOutputStream(out);
			os.writeObject(user);
			return out.toByteArray();
		} catch (Exception e) {
			throw new SerializationException(e);
		}
	}

	public static User javaDeserialize(byte[] b) {
		try {
			ByteArrayInputStream in = new ByteArrayInputStream(b);
			ObjectInputStream is = new ObjectInputStream(in);
			return (User) is.readObject();
		} catch (Exception e) {
			throw new SerializationException(e);
		}
	}
}

 

 

 

 

评论

5 楼 kane_xie 2015-07-05  

793059909 写道

我的结果怎么和你的不一样：
Type = json
Serialize cost = 48ms
Deserialize cost = 49ms
Type = java
Serialize cost = 25ms
Deserialize cost = 56ms

Code:

因为writer和parser没有初始化，JSON.parseObject(JSON.toJSONString(new User()), User.class);

4 楼 793059909 2015-07-02  

https://github.com/alibaba/fastjson
不测不知道，一测吓一跳啊

3 楼 793059909 2015-07-02  

fastjson-1.2.6.jar

2 楼 793059909 2015-07-02  

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.net.UnknownHostException;
import java.util.Date;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.parser.ParserConfig;
import com.alibaba.fastjson.serializer.SerializeConfig;

class User implements Serializable {
private static final long serialVersionUID = -2513747641863637392L;

User() {
}
}

public class Test {
public static ParserConfig pc = new ParserConfig();
public static SerializeConfig sc = new SerializeConfig();

public static void main(String[] args) throws UnknownHostException {
test("json");
test("java");
}

private static void test(String type) {
System.out.println("Type = " + type);
long start = new Date().getTime();
byte[] b = serialize(new User(), type);
long mid = new Date().getTime();
System.out.println("Serialize cost = " + (mid - start) + "ms");
deserialize(b, type);
System.out.println("Deserialize cost = " + (new Date().getTime() - mid + "ms"));
}

public static byte[] serialize(User user, String type) {
byte[] b = null;
for (int i = 0; i < 1000; i++) {
if ("java".equalsIgnoreCase(type)) {
b = javaSerialize(user);
} else if ("json".equalsIgnoreCase(type)) {
b = jsonSerialize(user);
}
}
return b;
}

public static User deserialize(byte[] b, String type) {
User user = null;
for (int i = 0; i < 1000; i++) {
if ("java".equalsIgnoreCase(type)) {
user = javaDeserialize(b);
} else if ("json".equalsIgnoreCase(type)) {
user = jsonDeserialize(b);
}
}
return user;
}

public static byte[] jsonSerialize(User user) {
return JSON.toJSONString(user).getBytes();
}

public static User jsonDeserialize(byte[] b) {
return JSON.parseObject(new String(b), User.class);
}

public static byte[] javaSerialize(User user) {
try {
ByteArrayOutputStream out = new ByteArrayOutputStream();
ObjectOutputStream os = new ObjectOutputStream(out);
os.writeObject(user);
return out.toByteArray();
} catch (Exception e) {
return null;
}
}

public static User javaDeserialize(byte[] b) {
try {
ByteArrayInputStream in = new ByteArrayInputStream(b);
ObjectInputStream is = new ObjectInputStream(in);
return (User) is.readObject();
} catch (Exception e) {
return null;
}
}
}

1 楼 793059909 2015-07-02  

我的结果怎么和你的不一样：
Type = json
Serialize cost = 48ms
Deserialize cost = 49ms
Type = java
Serialize cost = 25ms
Deserialize cost = 56ms

Code: