1.简单加密&解密

 1 package com.java7.myencrypt.main; 2  3 import java.io.File; 4 import java.io.FileInputStream; 5 import java.io.FileNotFoundException; 6 import java.io.FileOutputStream; 7 import java.io.IOException; 8  9 public class MyEncrypt {10     public static void main(String[] args) {11         try {12             File inFile = new File("inFile.txt");13             File outFile = new File("outFile.txt");14             15             if (inFile.createNewFile()) {16                 System.out.println("File is created!");17             } else {18                 System.out.println("File already exists.");19             }20             21             FileInputStream fis = new FileInputStream(inFile);22             FileOutputStream fos = new FileOutputStream(outFile);23 24             System.out.println(fis.available());25             int length = fis.available();26             for(int i = 0; i < length; i++) {27                 fos.write(fis.read()+100);28             }29         } catch (FileNotFoundException e) {30             // TODO Auto-generated catch block31             e.printStackTrace();32         } catch (IOException e) {33             // TODO Auto-generated catch block34             e.printStackTrace();35         }36     }37 }

 1 package com.java7.mydecrypt.main; 2  3 import java.io.File; 4 import java.io.FileInputStream; 5 import java.io.FileNotFoundException; 6 //import java.io.FileOutputStream; 7 import java.io.IOException; 8  9 public class MyDecrypt {10     public static void main(String[] args) {11         try {12             File dcFile = new File("outFile.txt");13 //            File dcNewFile = new File("dcNewFile.txt");14             15             if(dcFile.exists()) {16                 System.out.println("File already exists.");17             } else {18                 System.out.println("File not found.");19             }20 //            if(dcNewFile.createNewFile()){21 //                System.out.println("File is created!");22 //            } else {23 //                System.out.println("File already exists.");24 //            }25             26             FileInputStream fis = new FileInputStream(dcFile);27 //            FileOutputStream fos = new FileOutputStream(dcNewFile);28 29             System.out.println(fis.available());30             int length = fis.available();31             for(int i = 0; i < length; i++) {32                 System.out.print((char)(fis.read()-100));33 //                fos.write((fis.read()-100));34             }35         } catch (FileNotFoundException e) {36             // TODO Auto-generated catch block37             e.printStackTrace();38         } catch (IOException e) {39             // TODO Auto-generated catch block40             e.printStackTrace();41         }42     }43 }