我只是写了一篇关于如何达到这一点的描述，但是认为发布代码并保留它很容易:)
据我所知，test3（）的性能应与test1（）相同-唯一的区别是捕获异常的位置（在test1（）的调用方法内，在test3（）的被调用方法内）
为什么test3（）通常需要在test1（）和test2（）之间的某个时间才能完成？
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
public class Test {
public static void main(String[] args) {
warmup();
test1(2500000); // Exception caught inside the loop
test2(2500000); // Exception caught outside the loop
test3(2500000); // Exception caught "inside" the loop, but in the URLEncoder.encode() method
}
private static void warmup() {
// Let URLEncoder do whatever startup it needs before we hit it
String encoding = System.getProperty("file.encoding");
try {
URLEncoder.encode("ignore", encoding);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private static void test1(int count) {
String encoding = System.getProperty("file.encoding");
long start = System.currentTimeMillis();
for (int i = 0; i < count; i++) {
try {
URLEncoder.encode("test 1 " + i, encoding);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
long end = System.currentTimeMillis();
System.out.println("Performed " + count + " encodings trying to catch each in " + (end - start) + "ms");
}
private static void test2(int count) {
String encoding = System.getProperty("file.encoding");
long start = System.currentTimeMillis();
try {
for (int i = 0; i < count; i++) {
URLEncoder.encode("test 2" + i, encoding);
}
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
long end = System.currentTimeMillis();
System.out.println("Performed " + count + " encodings trying to catch all in " + (end - start) + "ms");
}
private static void test3(int count) {
long start = System.currentTimeMillis();
for (int i = 0; i < count; i++) {
URLEncoder.encode("test 3 " + i);
}
long end = System.currentTimeMillis();
System.out.println("Performed " + count + " encodings with a deprecated method in " + (end - start) + "ms");
}
}
运行它会给我（在Windows XP上为JDK 1.6.0_13）输出：
Performed 2500000 encodings trying to catch each in 4906ms
Performed 2500000 encodings trying to catch all in 2454ms
Performed 2500000 encodings with a deprecated method in 2953ms
因此，响应非常接近（我们正在谈论的东西太微不足道了，这是不相关的），但是我很好奇！
后来...
人们建议JVM优化妨碍了人们的发展-我同意。因此，我将每个测试细分为它自己的类/ main方法，并分别进行了测试。结果如下：
1 - Performed 2500000 encodings trying to catch each in 5016ms
1 - Performed 5000000 encodings trying to catch each in 7547ms
1 - Performed 5000000 encodings trying to catch each in 7515ms
1 - Performed 5000000 encodings trying to catch each in 7531ms
2 - Performed 2500000 encodings trying to catch all in 4719ms
2 - Performed 5000000 encodings trying to catch all in 7250ms
2 - Performed 5000000 encodings trying to catch all in 7203ms
2 - Performed 5000000 encodings trying to catch all in 7250ms
3 - Performed 2500000 encodings with a deprecated method in 5297ms
3 - Performed 5000000 encodings with a deprecated method in 8015ms
3 - Performed 5000000 encodings with a deprecated method in 8063ms
3 - Performed 5000000 encodings with a deprecated method in 8219ms
有趣的观察：
在自己的JVM中，减少了捕获每个调用与捕获循环外的所有内容之间的差距（我认为由于一次执行的所有其他迭代，优化不会在“一次测试全部完成”的情况下就花了很多精力）
现在，我这一边的try / catch与URLEncoder.encode（）内部的try / catch之间的差距要小得多（在5000000次迭代中间隔了半秒），但是仍然始终在那里。
最佳答案
按照您发布的顺序运行它：
执行了2500000种编码，试图
在34208ms内捕捉到每个
执行了2500000种编码，试图捕获所有
在31708毫秒内执行2500000编码
在30738ms中弃用的方法
冲销订单：
执行2500000个编码
32598ms中已弃用的方法已执行
2500000种编码试图捕捉所有
在31239毫秒内执行2500000编码
试图在31208ms内捕捉到每个
因此，我实际上并不认为您在看自己在看的东西（当然，test1的速度不会比test3慢66％，这是基准测试所建议的）
关于java - Java异常循环和弃用(或者是URLEncoding吗？)，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/905126/