??????????????xxxBusinessException
public class xxxBusinessException extends ApplicationException
{
public xxxBusinessException(String s){
super(s);
};
import java.io.PrintStream;
import java.io.PrintWriter;
public class ApplicationException extends Exception {
/** A wrapped Throwable */
protected Throwable cause;
public ApplicationException() {
super("Error occurred in application.");
}
public ApplicationException(String message)  {
super(message);
}
public ApplicationException(String message?? Throwable cause)  {
super(message);
this.cause = cause;
}
// Created to match the JDK 1.4 Throwable method.
public Throwable initCause(Throwable cause)  {
this.cause = cause;
return cause;
}
public String getMessage() {
// Get this exception‘s message.
String msg = super.getMessage();
Throwable parent = this;
Throwable child;
// Look for nested exceptions.
while((child = getNestedException(parent)) != null) {
// Get the child‘s message.
String msg2 = child.getMessage();
// If we found a message for the child exception??
// we append it.
if (msg2 != null) {
if (msg != null) {
msg += ": " + msg2;
} else {
msg = msg2;
}
}
// Any nested ApplicationException will append its own
// children?? so we need to break out of here.
if (child instanceof ApplicationException) {
break;
}
parent = child;
}
// Return the completed message.
return msg;
}
public void printStackTrace() {
// Print the stack trace for this exception.
super.printStackTrace();
Throwable parent = this;
Throwable child;
// Print the stack trace for each nested exception.
while((child = getNestedException(parent)) != null) {
if (child != null) {
System.err.print("Caused by: ");
child.printStackTrace();
if (child instanceof ApplicationException) {
break;
}
parent = child;
}
}
}
public void printStackTrace(PrintStream s) {
// Print the stack trace for this exception.
super.printStackTrace(s);
Throwable parent = this;
Throwable child;
// Print the stack trace for each nested exception.
while((child = getNestedException(parent)) != null) {
if (child != null) {
s.print("Caused by: ");
child.printStackTrace(s);
if (child instanceof ApplicationException) {
break;
}
parent = child;
}
}
}
public void printStackTrace(PrintWriter w) {
// Print the stack trace for this exception.
super.printStackTrace(w);
Throwable parent = this;
Throwable child;
// Print the stack trace for each nested exception.
while((child = getNestedException(parent)) != null) {
if (child != null) {
w.print("Caused by: ");
child.printStackTrace(w);
if (child instanceof ApplicationException) {
break;
}
parent = child;
}
}
}
public Throwable getCause()  {
return cause;
}
}
??????"????"??????????????doBusiness()????????????????????
public void doBusiness() throw xxxBusinessException
{
try
{
execute1(); // if it throw exception1
exexute2(); // if it throw exception 2
.... .....
}
catch (exception1 e1)
{
throw new xxxBusinessException(e1);
}
catch(exception2 e2)
{
throw new xxxBusinessException(e2);
}
........
}
?????????????
public void doBusiness() throw xxxBusinessException
{
try
{
execute1(); // if it throw exception1
exexute2(); // if it throw exception 2
.... .....
}
catch (Exception e)
{
// ????????????????????ж???????????????????
// throw new xxxBusinessException(e);
// ??????????????????xxxBusinessException"?????"RuntimeException
// ?????checked excption ??unchecked exception?????????
// ???xxxBusinessException????checked excpetion ??????????????????????RuntimeException
if(! e instanceof RuntimeException) throw new xxxBusinessException(e);
}
}
???????
????1??JAVA???????????: checked exception & unchecked excpetion
????2?????????в???????????ü?????Exception ????????checked excpetion????
????3??????е????????????????????????????RuntimeException??
????4???????????????Error????JVM?????????????;RuntimeException?????????????????;checked exception ?????????????????
????5?????????????????????????е???????y?RuntimeException????????????????????????????н?????????????Σ?