一般要测试软件或者库的性能，需要在多线程条件下进行。本文提供一种编写多线程性能测试的模板，方便大家参考和使用。
　　本文以AES加密和解密为例，并指出Cipher的获取在程序中的不同位置会对程序性能造成的影响。
　　程序代码如下：

 

package com.lazycat.secure.aes;
import java.nio.charset.Charset;
import java.security.NoSuchAlgorithmException;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;
public class AESCoder {
public static int count = 1000000;
public static CountDownLatch latch =new CountDownLatch(count);
public static void main(String[] args)throws Exception {
ExecutorService pool = Executors.newFixedThreadPool(200);
final byte[] payload = "{"msg":{"content":{"text":"JJH"，"tplId":0}，"from":{"name":"10000213"，"id":1，"type":0}，"to":{"name":"10095812"，"id":10000213，"type":0}，"time":0，"txid":0，"subtype":1}，"type":"chat"}".getBytes(Charset.forName("utf-8"));
final String secureKey ="BBmFdTFVgAjgHNwRkWWRcOFFiBzAANFU9DmMAP1JpBmc.";
long start = System.currentTimeMillis();
for(int i = 0 ; i <count ; i++){
pool.execute(new Runnable() {
public void run() {
AESCoder coder = new AESCoder();
byte[] enret =null;
try {
enret = coder.encrypt(payload，secureKey);
byte[] deret = coder.decrypt(enret， secureKey);
System.out.println(new String(deret，"utf-8"));
} catch (Exception e) {
e.printStackTrace();
}
latch.countDown();
}
});
}
latch.await();
System.out.println(System.currentTimeMillis() - start);
pool.shutdown();
}
private byte[] encrypt(byte[] payload，String securekey)throws Exception{
byte[] enCodeFormat = securekey.substring(0， 16).getBytes();
SecretKeySpec key = newSecretKeySpec(enCodeFormat，"AES");
Cipher cipher = CliperInstance.getInstance();//创建密码器
//Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE， key);//初始化
byte[] result = cipher.doFinal(payload);
return result;
}
public byte[] decrypt(byte[] buffer，StringsecureKey)throws Exception{
byte[] enCodeFormat = secureKey.substring(0，16).getBytes();
SecretKeySpec key = newSecretKeySpec(enCodeFormat，"AES");
//Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");//创建密码器
Cipher cipher = CliperInstance.getInstance();
cipher.init(Cipher.DECRYPT_MODE， key);//初始化
byte[] result = cipher.doFinal(buffer);
return result;
}
}
class CliperInstance {
private static ThreadLocal<Cipher> cipherTL =new ThreadLocal<Cipher>(){
@Override
protected Cipher initialValue() {
try {
return Cipher.getInstance("AES/ECB/PKCS5Padding");
}catch(Exception e){
return null;
}
}
};
public static   CiphergetInstance() throws NoSuchAlgorithmException， NoSuchPaddingException{
returncipherTL.get();
}
}