Java 编译错误:在相应的try语句体中从未引发异常
为了更好地学习Java,我一直在尝试理解异常处理。我无法理解为什么下面的代码无法编译 编译器消息是:Java 编译错误:在相应的try语句体中从未引发异常,java,exception,checked-exceptions,Java,Exception,Checked Exceptions,为了更好地学习Java,我一直在尝试理解异常处理。我无法理解为什么下面的代码无法编译 编译器消息是: TestExceptionHandling.java:12: error: exception StupidException is never thrown in body of corresponding try statement catch (StupidException stupidEx) { ^ 在try块中,调用方
TestExceptionHandling.java:12: error: exception StupidException is never thrown in body of corresponding try statement
catch (StupidException stupidEx) {
^
在try
块中,调用方法exTest.doExTest()。在这个方法中,我捕获一个InterruptedException,并在它的catch
块中抛出一个新的StupidException
那么为什么编译器说它没有被抛出呢?我错过了什么?请任何专家帮我看看我的错误好吗
public class TestExceptionHandling {
public static void main(String argv[]) {
String output = "";
try {
output = "\nCalling method doExTest:\n";
exTest.doExTest();
}
catch (StupidException stupidEx) {
System.out.println("\nJust caught a StupidException:\n " + stupidEx.toString());
}
System.out.println(output);
}
}
class exTest {
static long mainThreadId;
protected static void doExTest() { //throws StupidException
mainThreadId = Thread.currentThread().getId();
Thread t = new Thread(){
public void run(){
System.out.println("Now in run method, going to waste time counting etc. then interrupt main thread.");
// Keep the cpu busy for a while, so other thread gets going...
for (int i = 0; i < Integer.MAX_VALUE; i++) {
int iBoxed = (int)new Integer(String.valueOf(i));
String s = new String("This is a string" + String.valueOf(iBoxed));
}
// find thread to interrupt...
Thread[] threads = new Thread[0];
Thread.enumerate(threads);
for (Thread h: threads) {
if (h.getId() == mainThreadId) {
h.interrupt();
}
}
}
};
t.start();
try {
Thread.sleep(5000);
}
catch (InterruptedException e){
System.out.println("\nAn InterruptedException " + e.toString() + " has occurred. Exiting...");
throw new StupidException("Got an InterruptedException ", e); // ("Got an InterruptedException. Mutated to StupidException and throwing from doExTest to caller...", e);
}
}
}
class StupidException extends Exception {
public StupidException(String message, Throwable t) {
super(message + " " + t.toString());
}
public String toString() {
return "Stupid Exception: " + super.toString();
}
}
公共类TestExceptionHandling{
公共静态void main(字符串argv[]){
字符串输出=”;
试一试{
output=“\n调用方法doExTest:\n”;
doExTest();
}
捕获(StupidException stupidEx){
System.out.println(“\n刚刚捕获了一个StupidException:\n”+stupidEx.toString());
}
系统输出打印项次(输出);
}
}
类外部测试{
静态长主线程ID;
受保护的静态void doExTest(){//抛出StupidException
mainThreadId=Thread.currentThread().getId();
线程t=新线程(){
公开募捐{
System.out.println(“现在运行方法,将浪费时间计数等,然后中断主线程”);
//让cpu保持忙碌一段时间,以便其他线程继续运行。。。
对于(int i=0;i
方法需要显式声明它们抛出异常(运行时异常除外,这有点不同)。尝试将您的doExTest
方法声明为
protected static void doExTest() throws StupidException {
...
}
doExTest()
必须声明为抛出StupidException
。好的,这是可行的:我想可以在调用方法中声明它,在那里我捕获它。越来越清楚了!