iodemo.out

DES RSA MD5 实现身份认证

1: //: c11:IOStreamDemo.java
2: // Typical I/O stream configurations. 
3: 
4: import java.io.*;
5: 
6: 
7: public class IOStreamDemo {
8: 	
9: // Throw exceptions to console:
10: 	
11: public static void main(String[] args)
12: throws IOException {
13: // 1. Reading input by lines: 
14: 	
15: 
16: BufferedReader in =new BufferedReader(new FileReader("IOStreamDemo.java")); 
17: String s, s2 = new String();
18: while((s = in.readLine())!= null)
19: s2 += s + "\n";
20: in.close();
21: 
22: 
23: // 1b. Reading standard input: 
24: BufferedReader stdin =new BufferedReader(new InputStreamReader(System.in)); 
25: System.out.print("Enter a line:"); 
26: System.out.println(stdin.readLine());
27: 
28: 
29: // 2. Input from memory
30: StringReader in2 = new StringReader(s2);
31: int c;
32: while((c = in2.read()) != -1) 
33: 	System.out.print((char)c);
34: 
35: 
36: // 3. Formatted memory input 
37: try 
38: {
39: DataInputStream in3 =new DataInputStream(new ByteArrayInputStream(s2.getBytes())); 
40: while(true) 
41: 	System.out.print((char)in3.readByte());
42: 
43: } catch(EOFException e) 
44: 
45: { 
46: 	System.err.println("End of stream");
47: }
48: 
49: 
50: // 4. File output 
51: try {
52: BufferedReader in4 =new BufferedReader(new StringReader(s2)); 
53: PrintWriter out1 =new PrintWriter(new BufferedWriter(new FileWriter("IODemo.out")));
54: int lineCount = 1;
55: while((s = in4.readLine()) != null ) 
56: 	out1.println(lineCount++ + ": " + s); 
57: out1.close();
58: } catch(EOFException e) 
59: { System.err.println("End of stream");
60: }
61: 
62: 
63: // 5. Storing & recovering data 
64: try {
65: DataOutputStream out2 =new DataOutputStream(new BufferedOutputStream(new FileOutputStream("Data.txt"))); 
66: out2.writeDouble(3.14159); 
67: out2.writeChars("That was pi\n"); 
68: out2.writeBytes("That was pi\n");
69: out2.close();
70: DataInputStream in5 =new DataInputStream(new BufferedInputStream(new FileInputStream("Data.txt"))); 
71: BufferedReader in5br =new BufferedReader(new InputStreamReader(in5));
72: 
73: // Must use DataInputStream for data: System.out.println(in5.readDouble());
74:  
75: 
76: // Can now use the "proper" readLine():
77: System.out.println(in5br.readLine());
78: // But the line comes out funny.
79: // The one created with writeBytes is OK: System.out.println(in5br.readLine());
80: } catch(EOFException e) { System.err.println("End of stream");
81: }
82: 
83: 
84: // 6. Reading/writing random access files
85: 
86: RandomAccessFile rf=new RandomAccessFile("rtest.dat", "rw");
87: for(int i = 0; i < 10; i++) rf.writeDouble(i*1.414);
88: rf.close();
89: 
90: 
91: rf =
92: new RandomAccessFile("rtest.dat", "rw");
93: rf.seek(5*8); rf.writeDouble(47.0001); rf.close();
94: 
95: 
96: rf =new RandomAccessFile("rtest.dat", "r"); 
97: for(int i = 0; i < 10; i++) 
98: 	System.out.println("Value " + i + ": " +rf.readDouble());
99: 
100: rf.close();
101: 
102: }
103: }
104: 
105: 
106: 
107: