练习.加密(Encrypt) & 解密(Decrypt)

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 block
31             e.printStackTrace();
32         } catch (IOException e) {
33             // TODO Auto-generated catch block
34             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 outFile = new File("outFile.txt");
13             File dcNewFile = new File("dcNewFile.txt");
14             
15             if(outFile.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(outFile);
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                 // 在控制台打印结果
33 //                System.out.print((char)(fis.read()-100));
34                 // 上下2条命令冲突（？）,选其一执行
35                 // 或生成新的文本文件（已解密）
36                 fos.write(fis.read()-100);
37             }
38         } catch (FileNotFoundException e) {
39             // TODO Auto-generated catch block
40             e.printStackTrace();
41         } catch (IOException e) {
42             // TODO Auto-generated catch block
43             e.printStackTrace();
44         }
45     }
46 }

2.进阶加密&解密

 1 package com.java7.mykey.main;
 2 
 3 import java.io.File;
 4 import java.io.FileNotFoundException;
 5 import java.io.FileOutputStream;
 6 import java.io.IOException;
 7 
 8 public class MyKey {
 9     public static void main(String[] args) {
10         try {
11             File keyFile = new File("keyFile.key");
12             
13             if(keyFile.createNewFile()) {
14                 System.out.println("File is created!");
15             } else {
16                 System.out.println("File already exists.");
17             }
18             
19             FileOutputStream fos = new FileOutputStream(keyFile);
20             
21             for(int i = 0; i < 128; i++) {
22                 fos.write((int)(Math.random() * 128));
23             }
24         } catch (FileNotFoundException e) {
25             // TODO Auto-generated catch block
26             e.printStackTrace();
27         } catch (IOException e) {
28             // TODO Auto-generated catch block
29             e.printStackTrace();
30         }
31     }
32 }

 1 package com.java7.mykeyencrypt.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 MyKeyEncrypt {
10     public static void main(String[] args) {
11         try {
12             // 读密钥文件
13             int[] keyArray = new int[128];
14             File keyFile = new File("keyFile.key");
15             FileInputStream keyFis = new FileInputStream(keyFile);
16             if(keyFile.exists()) {
17                 System.out.println("File exists.");
18             } else {
19                 System.out.println("File not found.");
20             }
21             for(int i = 0; i < 128; i++) {
22                 keyArray[i] = keyFis.read();
23             }
24             
25             
26             // 加密
27             File inFile = new File("inFile.txt");
28             File outFile = new File("keyEncrypt.txt");
29             
30             if(inFile.createNewFile()) {
31                 System.out.println("File is created!");
32             } else {
33                 System.out.println("File already exists.");
34             }
35             if(outFile.createNewFile()) {
36                 System.out.println("File is created!");
37             } else {
38                 System.out.println("File already exists.");
39             }
40             
41             FileInputStream inFis = new FileInputStream(inFile);
42             FileOutputStream outFos = new FileOutputStream(outFile);
43             
44 //            System.out.println(inFis.available());
45             int length = inFis.available();
46             for(int i = 0; i < length; i++) {
47                 // 
48                 // 
49 //                System.out.print((char)(inFis.read()+keyArray[i%128]));
50                 outFos.write(inFis.read()+keyArray[i%128]);
51             }
52         } catch (FileNotFoundException e) {
53             // TODO Auto-generated catch block
54             e.printStackTrace();
55         } catch (IOException e) {
56             // TODO Auto-generated catch block
57             e.printStackTrace();
58         }
59     }
60 }

 1 package com.java7.mykeydecrypt.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 MyKeyDecrypt {
10     public static void main(String[] args) {
11         try {
12             // 读密钥文件
13             int[] keyArray = new int[128];
14             File keyFile = new File("keyFile.key");
15             FileInputStream keyFis = new FileInputStream(keyFile);
16             
17             if(keyFile.exists()) {
18                 System.out.println("File exists.");
19             } else {
20                 System.out.println("File not found.");
21             }
22             
23             for(int i = 0; i < 128; i++) {
24                 keyArray[i] = keyFis.read();
25             }
26             
27             // 解密
28             File keyEncryptFile = new File("keyEncrypt.txt");
29             File keyDecryptFile = new File("keyDecrypt.txt");
30             if(keyEncryptFile.exists()) {
31                 System.out.println("File exists.");
32             } else {
33                 System.out.println("File not found.");
34             }
35             if(keyDecryptFile.createNewFile()) {
36                 System.out.println("File is created!");
37             } else {
38                 System.out.println("File already exists.");
39             }
40             
41             FileInputStream keyEncFis = new FileInputStream(keyEncryptFile);
42             FileOutputStream keyDecFos = new FileOutputStream(keyDecryptFile);
43             
44             int length = keyEncFis.available();
45             for(int i = 0; i < length; i++) {
46                 // 在控制台打印结果
47 //                System.out.print((char)(keyEncFis.read()-keyArray[i%128]));
48                 // 上下2条命令冲突（？）,选其一执行
49                 // 或生成新的文本文件（已解密）
50                 keyDecFos.write(keyEncFis.read()-keyArray[i%128]);
51             }
52         } catch (FileNotFoundException e) {
53             // TODO Auto-generated catch block
54             e.printStackTrace();
55         } catch (IOException e) {
56             // TODO Auto-generated catch block
57             e.printStackTrace();
58         }
59     }
60 }