Java异常处理

Java异常处理手段

try catch

一般方法

package exception;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;

public class TestException {

	public static void main(String[] args) {
		
		File f= new File("d:/test.exe");
		
		try{
			System.out.println("试图打开 d:/test.exe");
			new FileInputStream(f);
			System.out.println("成功打开");
		}catch(FileNotFoundException e){
			System.out.println("d:/test.exe不存在");
			e.printStackTrace();
		}
	}
}

使用异常的父类catch

package exception;
 
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
 
public class TestException {
 
    public static void main(String[] args) {
         
        File f= new File("d:/test.exe");
         
        try{
            System.out.println("试图打开 d:/test.exe");
            new FileInputStream(f);
            System.out.println("成功打开");
        }catch(Exception e){
            System.out.println("d:/test.exe不存在");
            e.printStackTrace();
        }   
    }
}

多异常捕捉

package exception;
 
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
 
public class TestException {
 
    public static void main(String[] args) {
 
        File f = new File("d:/test.exe");
 
        try {
            System.out.println("试图打开 d:/test.exe");
            new FileInputStream(f);
            System.out.println("成功打开");
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            Date d = sdf.parse("2016-06-03");
        } catch (FileNotFoundException e) {
            System.out.println("d:/test.exe不存在");
            e.printStackTrace();
        } catch (ParseException e) {
            System.out.println("日期格式解析错误");
            e.printStackTrace();
        }
    }
}

多异常捕捉2

package exception;
 
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
 
public class TestException {
 
    public static void main(String[] args) {
 
        File f = new File("d:/test.exe");
 
        try {
            System.out.println("试图打开 d:/test.exe");
            new FileInputStream(f);
            System.out.println("成功打开");
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            Date d = sdf.parse("2016-06-03");
        } catch (FileNotFoundException | ParseException e) {
            if (e instanceof FileNotFoundException)
                System.out.println("d:/test.exe不存在");
            if (e instanceof ParseException)
                System.out.println("日期格式解析错误");
 
            e.printStackTrace();
        }
    }
}