Java Tutorial/JSP/Exception — различия между версиями
Admin (обсуждение | вклад) м (1 версия) |
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Текущая версия на 05:07, 1 июня 2010
Содержание
- 1 Catching an ArithmeticException Exception
- 2 Catching an ArrayIndexOutOfBoundsException Exception
- 3 Causing a Runtime Error
- 4 Creating a Custom Exception Object
- 5 Nesting try/catch Statements
- 6 Output error message to console
- 7 Printing a Stack Trace to the Server Console
- 8 Throwing an Exception
- 9 Throwing Exceptions From Methods
- 10 Using a try/catch Block
Catching an ArithmeticException Exception
<HTML>
<HEAD>
<TITLE>Catching an ArithmeticException Exception</TITLE>
</HEAD>
<BODY>
<H1>Catching an ArithmeticException Exception</H1>
<%
try {
int array[] = new int[100];
array[100] = 100;
} catch (ArrayIndexOutOfBoundsException e) {
out.println("Array index out of bounds.");
} catch(ArithmeticException e) {
out.println("Arithmetic exception: " + e);
} catch(Exception e) {
out.println("An error occurred: " + e);
}
%>
</BODY>
</HTML>
Catching an ArrayIndexOutOfBoundsException Exception
<HTML>
<HEAD>
<TITLE>Catching an ArrayIndexOutOfBoundsException Exception</TITLE>
</HEAD>
<BODY>
<H1>Catching an ArrayIndexOutOfBoundsException Exception</H1>
<%
try {
int array[] = new int[100];
array[100] = 100;
} catch (ArrayIndexOutOfBoundsException e) {
out.println("Array index out of bounds.");
}
%>
</BODY>
</HTML>
Causing a Runtime Error
<HTML>
<HEAD>
<TITLE>Causing a Runtime Error</TITLE>
</HEAD>
<BODY>
<H1>Causing a Runtime Error</H1>
<%
int int1 = 1;
int1 = int1 / 0;
out.println("The answer is " + int1);
%>
</BODY>
</HTML>
Creating a Custom Exception Object
<HTML>
<HEAD>
<TITLE>Creating a Custom Exception Object</TITLE>
</HEAD>
<BODY>
<H1>Creating a Custom Exception Object</H1>
<%!
class MyException extends Exception
{
int value;
public String toString()
{
return "MyException " + value;
}
MyException(int v)
{
value = v;
}
}
void doWork(int value) throws MyException
{
if(value == 0){
throw new MyException(value);
}
}
%>
<%
try {
doWork(3);
doWork(2);
doWork(1);
doWork(0);
}
catch (MyException e) {
out.println("Exception: " + e);
}
%>
</BODY>
</HTML>
Nesting try/catch Statements
<HTML>
<HEAD>
<TITLE>Nesting try/catch Statements</TITLE>
</HEAD>
<BODY>
<H1>Nesting try/catch Statements</H1>
<%
try {
try {
int c[] = {0, 1, 2, 3};
c[4] = 4;
} catch(ArrayIndexOutOfBoundsException e) {
out.println("Array index out of bounds: " + e);
}
} catch(ArithmeticException e) {
out.println("Divide by zero: " + e);
}
%>
</BODY>
</HTML>
Output error message to console
<HTML>
<HEAD>
<TITLE>Building a simple error handling page.</TITLE>
</HEAD>
<BODY>
<%
try{
int value = 1;
value = value / 0;
}
catch (Exception e){
System.out.println(e.getMessage());
}
%>
</BODY>
</HTML>
Printing a Stack Trace to the Server Console
<HTML>
<HEAD>
<TITLE>Printing a Stack Trace to the Server Console</TITLE>
</HEAD>
<BODY>
<H1>Printing a Stack Trace to the Server Console</H1>
<%
try{
int value = 1;
value = value / 0;
}
catch (Exception e){
e.printStackTrace();
}
%>
</BODY>
</HTML>
Throwing an Exception
<html>
<head>
<title>Throwing an Exception</title>
</head>
<body>
<title>Throwing an Exception</title>
<%
try {
throw new ArithmeticException("Math Exception!");
} catch(ArithmeticException e) {
out.println("Exception message: " + e);
}
%>
</body>
</html>
Throwing Exceptions From Methods
<HTML>
<HEAD>
<TITLE>Throwing Exceptions From Methods</TITLE>
</HEAD>
<BODY>
<H1>Throwing Exceptions From Methods</H1>
<%!
void doWork() throws ArrayIndexOutOfBoundsException
{
int array[] = new int[100];
array[100] = 100;
}
%>
<%
try {
doWork();
} catch (ArrayIndexOutOfBoundsException e) {
out.println("Array out of bounds exception");
}
%>
</BODY>
</HTML>
Using a try/catch Block
<HTML>
<HEAD>
<TITLE>Using a try/catch Block</TITLE>
</HEAD>
<BODY>
<H1>Using a try/catch Block</H1>
<%
try{
int int1 = 1;
int1 = int1 / 0;
out.println("The answer is " + int1);
}
catch (Exception e){
out.println("An exception occurred: " + e.getMessage());
}
%>
</BODY>
</HTML>
