Exception

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import java.io.FileNotFoundException;import java.io.FileReader;import java.io.IOException;public class TestReadFile {public static void main(String[] args) {FileReader reader=null;try{reader=new FileReader("d:/a.txt");char a=(char)reader.read();char a2=(char)reader.read();System.out.println(""+a+a2);} catch(FileNotFoundException e){e.printStackTrace();}catch (IOException e) {                      /*不能交换位置，否则会报错Unreachable catch block for FileNotFoundException. It is already handled by the catch block for IOExceptionFileNotFoundException 是 IOException的一个子类，子类放前面，父类放后面*/e.printStackTrace(); }finally{                     //一般在finally里面要关闭资源try {if(reader!=null){reader.close();}} catch (IOException e) {e.printStackTrace();}}}}

try catch finally return 的执行顺序：

1.执行try ，catch，给定返回值

2.执行finally

3.return

例：

import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;public class TestReadFile {public static void main(String[] args) {String str =new TestReadFile().openFile();System.out.println(str);}String openFile(){try {System.out.println("aaa");FileInputStream fis=new FileInputStream("d:/a.txt");int a =fis.read();System.out.println("bbb");return "step1";} catch (FileNotFoundException e) {System.out.println("catching!!!!!!");e.printStackTrace();return "step2";          //先确定返回的值，并不会直接结束运行} catch (IOException e) {e.printStackTrace();return "step 3";}finally{System.out.println("finally!!!");//return "fff";            //不要在finally中使用return}}}

运行结果：

aaabbbfinally!!!step1

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