转载:http://budairenqin.iteye.com/blog/1500366
新项目开始之前领导让研究下公司原有的框架(基于struts1.2.9+spring2.0.6),比较古老了。读service基类时发现竟然将request穿透到了service层(request为BaseService的实例变量),这样service就变成了有状态Bean,使service层变成了非线程安全,导致用Spring容器管理service的时候不得不使用prototype的scope
我们知道,service由于要做事务的包装,需要创建代理对象,spring中使用JDK动态代理或者CGLIB动态代理来创建代理对象,据说JDK动态代理创建对象的时间快于CGLIB,但是性能比CGLIB差(接下来我会测试这个观点),所以我得出以下结论:
1.spring在bean的scope为prototype的情况下,因为是延迟实例化bean,所以最好使用JDK的API创建代理对象;
2.反之对于singleton对象,spring默认是容器启动时就初始化bean,最好使用CGLIB来创建对象
把service配置成singleton我觉得性能方面显然要更好些,如果非要将request穿透到service层,是不是可以考虑用ThreadLocal?
在测试之前,我们先确定spring是以什么方式使用JDK动态代理和CGLIB的,如图:
JDK动态代理:
CGLIB动态代理:
接下来对测试下JDK动态代理和CGLIB动态代理的性能(CGLIB测试代码也和spring一样使用MethodInterceptor)
先贴上测试代码
- public interface CountService {
- int count();
- }
- public class CountServiceImpl implements CountService {
- private int count = 0;
- public int count() {
- return ++count;
- }
- }
- import java.io.File;
- import java.io.FileNotFoundException;
- import java.io.FileOutputStream;
- import java.io.IOException;
- import java.lang.reflect.InvocationHandler;
- import java.lang.reflect.Method;
- import java.lang.reflect.Proxy;
- import java.text.DecimalFormat;
- import net.sf.cglib.core.DefaultGeneratorStrategy;
- import net.sf.cglib.proxy.Enhancer;
- import net.sf.cglib.proxy.MethodInterceptor;
- import net.sf.cglib.proxy.MethodProxy;
- @SuppressWarnings("unused")
- public class DynamicProxyPerformanceTest {
- public static void main(String[] args) throws Exception {
- CountService delegate = new CountServiceImpl();
- long time = System.currentTimeMillis();
- CountService jdkProxy = createJdkDynamicProxy(delegate);
- time = System.currentTimeMillis() - time;
- System.out.println("Create JDK Proxy: " + time + " ms");
- time = System.currentTimeMillis();
- CountService cglibProxy = createCglibDynamicProxy(delegate);
- time = System.currentTimeMillis() - time;
- System.out.println("Create CGLIB Proxy: " + time + " ms");
- for (int i = 0; i < 3; i++) {
- test(jdkProxy, "Run JDK Proxy: ");
- test(cglibProxy, "Run CGLIB Proxy: ");
- System.out.println("-------------------");
- }
- }
- private static void test(CountService service, String label) throws Exception {
- service.count(); // warm up
- int count = 10000000;
- long time = System.currentTimeMillis();
- for (int i = 0; i < count; i++) {
- service.count();
- }
- time = System.currentTimeMillis() - time;
- System.out.println(label + time + " ms, " + new DecimalFormat().format(count * 1000 / time) + " t/s");
- }
- private static CountService createJdkDynamicProxy(final CountService delegate) {
- CountService jdkProxy = (CountService) Proxy.newProxyInstance(ClassLoader.getSystemClassLoader(),
- new Class[] { CountService.class }, new JdkHandler(delegate));
- // 反汇编字节码用,测试的时候注释掉这段代码,不然影响测试结果
- // 下面一行代码参照java.lang.reflect.Proxy
- // byte[] proxyClassFile =
- // sun.misc.ProxyGenerator.generateProxyClass(
- // jdkProxy.getClass().getName(), jdkProxy.getClass().getInterfaces());
- // try {
- // FileOutputStream fos =
- // new FileOutputStream(new File(jdkProxy.getClass().getName() + ".class"));
- // fos.write(proxyClassFile, 0, proxyClassFile.length);
- // } catch (FileNotFoundException e) {
- // e.printStackTrace();
- // } catch (IOException e) {
- // e.printStackTrace();
- // }
- return jdkProxy;
- }
- private static class JdkHandler implements InvocationHandler {
- final Object delegate;
- JdkHandler(Object delegate) {
- this.delegate = delegate;
- }
- public Object invoke(Object object, Method method, Object[] objects) throws Throwable {
- return method.invoke(delegate, objects);
- }
- }
- private static CountService createCglibDynamicProxy(final CountService delegate) throws Exception {
- Enhancer enhancer = new Enhancer();
- enhancer.setSuperclass(CountServiceImpl.class);
- enhancer.setCallback(new MethodInterceptor() {
- @Override
- public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
- return proxy.invokeSuper(obj, args);
- }
- });
- CountServiceImpl cglibProxy = (CountServiceImpl) enhancer.create();
- // 反汇编字节码用,测试的时候注释掉这段代码,不然影响测试结果
- // 下面一行代码参照net.sf.cglib.core.AbstractClassGenerator类中byte[] b = strategy.generate(this);
- // byte[] proxyClassFile = new DefaultGeneratorStrategy().generate(enhancer);
- // try {
- // FileOutputStream fos =
- // new FileOutputStream(new File(cglibProxy.getClass().getName() + ".class"));
- // fos.write(proxyClassFile, 0, proxyClassFile.length);
- // } catch (FileNotFoundException e) {
- // e.printStackTrace();
- // } catch (IOException e) {
- // e.printStackTrace();
- // }
- return cglibProxy;
- }
- }
数据为执行三次,每次调用一千万次代理方法的结果
测试环境1:
JDK:fastdebug1.6
CGLIB:和spring2.0.6 使用同样的cglib-nodep-2.1_3.jar
CPU:P8400 2.53GHz 2.53GHz
测试结果1:
- Create JDK Proxy: 13 ms
- Create CGLIB Proxy: 201 ms
- Run JDK Proxy: 1571 ms, 897,559 t/s
- Run CGLIB Proxy: 824 ms, 1,711,244 t/s
- -------------------
- Run JDK Proxy: 1519 ms, 928,285 t/s
- Run CGLIB Proxy: 576 ms, 2,448,030 t/s
- -------------------
- Run JDK Proxy: 1546 ms, 912,073 t/s
- Run CGLIB Proxy: 590 ms, 2,389,941 t/s
- -------------------
CGLIB创建代理对象速度大概比JDK Proxy慢15倍,执行速度是JDK Proxy的2倍左右
测试环境2:
JDK:fastdebug1.7
CGLIB:和spring2.0.6 使用同样的cglib-nodep-2.1_3.jar
CPU:P8400 2.53GHz 2.53GHz
测试结果2:
- Create JDK Proxy: 14 ms
- Create CGLIB Proxy: 204 ms
- Run JDK Proxy: 1608 ms, 876,906 t/s
- Run CGLIB Proxy: 529 ms, 2,665,530 t/s
- -------------------
- Run JDK Proxy: 1591 ms, 886,276 t/s
- Run CGLIB Proxy: 405 ms, 3,481,642 t/s
- -------------------
- Run JDK Proxy: 1624 ms, 868,266 t/s
- Run CGLIB Proxy: 405 ms, 3,481,642 t/s
- -------------------
CGLIB创建代理对象速度大概比JDK Proxy慢15倍,执行速度是JDK Proxy的4倍左右
测试环境3:
JDK:jdk1.6.0_21
CGLIB:和spring2.0.6 使用同样的cglib-nodep-2.1_3.jar
CPU:P8400 2.53GHz 2.53GHz
测试结果3:
- Create JDK Proxy: 8 ms
- Create CGLIB Proxy: 99 ms
- Run JDK Proxy: 911 ms, 1,547,821 t/s
- Run CGLIB Proxy: 435 ms, 3,241,529 t/s
- -------------------
- Run JDK Proxy: 870 ms, 1,620,764 t/s
- Run CGLIB Proxy: 399 ms, 3,533,998 t/s
- -------------------
- Run JDK Proxy: 894 ms, 1,577,254 t/s
- Run CGLIB Proxy: 404 ms, 3,490,260 t/s
- -------------------
CGLIB创建代理对象速度大概比JDK Proxy慢10倍以上,执行速度是JDK Proxy的2倍左右
测试环境4:
JDK:jdk1.7.0_02
CGLIB:和spring2.0.6 使用同样的cglib-nodep-2.1_3.jar
CPU:P8400 2.53GHz 2.53GHz
测试结果4:
- Create JDK Proxy: 43 ms
- Create CGLIB Proxy: 129 ms
- Run JDK Proxy: 940 ms, 1,500,069 t/s
- Run CGLIB Proxy: 299 ms, 4,715,937 t/s
- -------------------
- Run JDK Proxy: 921 ms, 1,531,015 t/s
- Run CGLIB Proxy: 269 ms, 5,241,878 t/s
- -------------------
- Run JDK Proxy: 932 ms, 1,512,945 t/s
- Run CGLIB Proxy: 265 ms, 5,321,001 t/s
- -------------------
CGLIB创建代理对象速度大概比JDK Proxy慢3倍,执行速度是JDK Proxy的3倍以上
字节码比较:
把测试代码中被注释的部分打开,生成class文件后执行javap -c 类名
JDK动态代理生成的字节码:
- public final int count() throws ;
- Code:
- 0: aload_0
- 1: getfield #16 // Field java/lang/reflect/Proxy.h:Ljava/lang/reflect/InvocationHandler;
- 4: aload_0
- 5: getstatic #50 // Field m3:Ljava/lang/reflect/Method;
- 8: aconst_null
- 9: invokeinterface #28, 4 // InterfaceMethod java/lang/reflect/InvocationHandler.invoke:(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;
- 14: checkcast #52 // class java/lang/Integer
- 17: invokevirtual #55 // Method java/lang/Integer.intValue:()I
- 20: ireturn
- 21: athrow
- 22: astore_1
- 23: new #42 // class java/lang/reflect/UndeclaredThrowableException
- 26: dup
- 27: aload_1
- 28: invokespecial #45 // Method java/lang/reflect/UndeclaredThrowableException."<init>":(Ljava/lang/Throwable;)V
- 31: athrow
- Exception table:
- from to target type
- 0 21 21 Class java/lang/Error
- 0 21 21 Class java/lang/RuntimeException
- 0 21 22 Class java/lang/Throwable
CGLIB生成的字节码:
- public final int count();
- Code:
- 0: aload_0
- 1: getfield #37 // Field CGLIB$CALLBACK_0:Lnet/sf/cglib/proxy/MethodInterceptor;
- 4: dup
- 5: ifnonnull 17
- 8: pop
- 9: aload_0
- 10: invokestatic #41 // Method CGLIB$BIND_CALLBACKS:(Ljava/lang/Object;)V
- 13: aload_0
- 14: getfield #37 // Field CGLIB$CALLBACK_0:Lnet/sf/cglib/proxy/MethodInterceptor;
- 17: dup
- 18: ifnull 52
- 21: aload_0
- 22: getstatic #43 // Field CGLIB$count$0$Method:Ljava/lang/reflect/Method;
- 25: getstatic #45 // Field CGLIB$emptyArgs:[Ljava/lang/Object;
- 28: getstatic #47 // Field CGLIB$count$0$Proxy:Lnet/sf/cglib/proxy/MethodProxy;
- 31: invokeinterface #53, 5 // InterfaceMethod net/sf/cglib/proxy/MethodInterceptor.intercept:(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;Lnet/sf/cglib/proxy/MethodProxy;)Ljava/lang/Object;
- 36: dup
- 37: ifnonnull 45
- 40: pop
- 41: iconst_0
- 42: goto 51
- 45: checkcast #55 // class java/lang/Number
- 48: invokevirtual #58 // Method java/lang/Number.intValue:()I
- 51: ireturn
- 52: aload_0
- 53: invokespecial #35 // Method CountServiceImpl.count:()I
- 56: ireturn