java自定义异常作用
}二、 第二种定义方式:继承Throwable 类public class MySecondException extends Throwable {public MySecondException() {super();}public MySecondException(String msg) {super(msg);}public MySecondException(String msg, Throwable cause) {super(msg, cause);}public MySecondException(Throwable cause) {super(cause);}}三、测试/*** 自定义异常类的使用* @author new**/public class TestMyException {public static void firstException() throws MyFirstException{throw new MyFirstException("\"firstException()\" method occurs an exception!");}public static void secondException() throws MySecondException{throw new MySecondException("\"secondException()\" method occurs an exception!");}public static void main(String[] args) {try {TestMyException。
哪种JAVA快速开发平台可以自定义组件?谢谢!
我之前用的是MyEclipse,虽然号称支持自定义的组件,但实际使用中需要每个页面逐个修改,一旦产生BUG改起来很让人崩溃,后来用了家起步科技的x5,综合比较到现在为止都是我见到过的在这方面做的最好的开发平台,组件代码都可以从网上找到,在他们的资源库里一次修改页面级就全改了,关键是免费使用还配带免费培训,建议楼主了解一下。
java 自定义异常
一、第一种定义方式,继承Exception类
public class MyFirstException extends Exception {
public MyFirstException() {
super();
public MyFirstException(String msg) {
super(msg);
public MyFirstException(String msg, Throwable cause) {
super(msg, cause);
public MyFirstException(Throwable cause) {
super(cause);
//自定义异常类的主要作用是区分异常发生的位置,当用户遇到异常时,
//根据异常名就可以知道哪里有异常,根据异常提示信息进行修改。
二、 第二种定义方式:继承Throwable 类
public class MySecondException extends Throwable {
public MySecondException() {
super();
public MySecondException(String msg) {
super(msg);
public MySecondException(String msg, Throwable cause) {
super(msg, cause);
public MySecondException(Throwable cause) {
super(cause);
* 自定义异常类的使用
* @author new
public class TestMyException {
public static void firstException() throws MyFirstException{
throw new MyFirstException("\"firstException()\" method occurs an exception!");
public static void secondException() throws MySecondException{
throw new MySecondException("\"secondException()\" method occurs an exception!");
public static void main(String[] args) {
try {
TestMyException.firstException();
TestMyException.secondException();
} catch (MyFirstException e1){
System.out.println("Exception: " + e1.getMessage());
e1.printStackTrace();
} catch (MySecondException e2){
System.out.println("Exception: " + e2.getMessage());
e2.printStackTrace();
//当一个try块后面跟着多个catch块时,如果发生的异常匹配第一个catch块的参数,便将异常处理权利交给第一个catch块。
//如果发生的异常与第一个catch块不匹配,便看是否与第二个catch块匹配,依次下去,如果到最后依然无法匹配该异常,
//便需要在方法声明中添加一条throw语句,将该异常抛出。
//因此,在有多个catch块,而且每次处理的异常类型具有继承关系时,应该首先catch子类异常,再catch父类异常。
//比如,如果MySecondException继承MyFirstException,那么最好将catch (MySecondException e2)放在前面,
//把catch (MyFirstException e1)放在后面。
java中如何使用自定义异常?
class NotScoreException extends Exception
public NotScoreException()
super();
public NotScoreException(String message)
super(message);
public class MyExceptionTest
public static String getGrade(double score)throws NotScoreException
if(score<=100&&score>=60)
return "及格";
else if(score<60&&score>=0)
return "不及格";
else
throw new NotScoreException("输入成绩有误");
public static void main(String[] args)
try
System.out.println("75分的等级为:"+getGrade(75));
System.out.println("105分的等级为:"+getGrade(105));
catch (NotScoreException e)
System.out.println("发生自定义异常,异常信息为:"+e.getMessage());