spring-core源码走读
asm
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ASM is an all purpose Java bytecode manipulation and analysis framework.
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ASM是一个万能的java字节码操纵和分析框架
cglib
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Byte Code Generation Library is high level API to generate and transform JAVA byte code
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高层级的生成和转换Java字节码的字节码生成库
objenesis
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Objenesis is a small Java library that serves one purpose:To instantiate a new object of a particular class.
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Objenesis是一个只为特殊类初始化对象小型Java库
lang
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定义八个注解
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NonNull.class
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NonNullApi.class
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NonNullFields.class
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Nullable.class
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UsesJava7.class
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UsesJava8.class
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UsesSunHttpServer.class
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UsesSunMisc.class
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util
backoff
重试算法
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定义退避算法
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BackOff.class
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BackOffExecution.class
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ExponentialBackOff.class 指数重试间隔实现
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FixedBackOff.class 固定重试间隔实现
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用于封装重试逻辑
使用说明
BackOffExecution exec = backOff.start();
// In the operation recovery/retry loop:
long waitInterval = exec.nextBackOff();
if (waitInterval == BackOffExecution.STOP) {
// do not retry operation
}
else {
// sleep, e.g. Thread.sleep(waitInterval)
// retry operation
}
}
测试代码
package com.zby.util.backoff;
import java.util.Date;
import org.springframework.util.backoff.BackOff;
import org.springframework.util.backoff.BackOffExecution;
import org.springframework.util.backoff.ExponentialBackOff;
import org.springframework.util.backoff.FixedBackOff;
public class BackoffDemo {
public static void main(String[] args) throws Exception {
//BackOff backOff = new FixedBackOff(1000, 10);
BackOff backOff = new ExponentialBackOff(500, 2);
BackOffExecution backOffExecution = backOff.start();
int successTime=7;
for(int i=0;;i++) {
System.out.println("重试："+backOffExecution);
long waitInterval = backOffExecution.nextBackOff();
if (waitInterval == BackOffExecution.STOP) {
System.out.println("执行失败：" + backOffExecution);
break;
} else {
Thread.sleep(waitInterval);
System.out.println("准备执行操作，当前时间："+new Date());
boolean success = operation(successTime==i);
if(success) {
break;
}
}
}
}
public static boolean operation(boolean success) {
System.out.println("执行结果："+success);
return success;
}
}
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可以封装一下把公共代码封装起来，提供重试机制，如：
package com.zby.util.backoff;
import java.util.Date;
import org.springframework.util.backoff.BackOff;
import org.springframework.util.backoff.BackOffExecution;
import org.springframework.util.backoff.FixedBackOff;
public abstract class FixedBackOffRunnable implements Runnable{
private BackOffExecution backOffExecution;
public FixedBackOffRunnable(long interval, long maxAttempts) {
BackOff backOff = new FixedBackOff(interval, maxAttempts);
backOffExecution = backOff.start();
}
public void run() {
while (true) {
System.out.println("重试：" + backOffExecution);
long waitInterval = backOffExecution.nextBackOff();
if (waitInterval == BackOffExecution.STOP) {
System.out.println("执行失败：" + backOffExecution);
break;
} else {
try {
Thread.sleep(waitInterval);
} catch (InterruptedException e1) {
e1.printStackTrace();
}
System.out.println("准备执行操作，当前时间：" + new Date());
boolean retry=false;
try {
doRun();
} catch (RetryableExeception e) {
retry=true;
}
if(