randomfiletest.java

一些JavaAPI测试的源代码(包括一些Java中常用的数据结构类

/**
 *Author Miracle
 *Time	2005.11.26 12:40
 *
 */
 
 /*** Test RandomAccessFile ***/
 import java.io.*;
 import java.io.RandomAccessFile;
 
 
 public class RandomFileTest
 {
 	public static void main(String [] args) throws Exception 
 	{
 		Employee e1 = new Employee("Miracle",20);
 		//Employee e2 = new Employee("zhoutao",20);
 		Employee e2 = new Employee("zhoutao",25);
 		/* When the number > 256, --> num-256*/
 		/* > one byte  */
 		Employee e3 = new Employee("zheshandian",21);
 		RandomAccessFile ra = new RandomAccessFile("Employee.txt","rw");	
 		ra.write(e1.name.getBytes());
 		//ra.write(e1.age);	//only write one byte;
 		ra.writeInt(e1.age); // write four byte;
 		
 		ra.write(e2.name.getBytes());
 		//ra.write(e2.age);	
 		ra.writeInt(e2.age);
 		
 		ra.write(e3.name.getBytes());
 		//ra.write(e3.age);
 		ra.writeInt(e3.age);
 		
 		ra.close();
 		
 		
 		byte[] buff = new byte[Employee.LEN];
 		int length=0;
 		String strName=null;
 		RandomAccessFile raf = new RandomAccessFile("Employee.txt","rw");
 		raf.skipBytes(Employee.LEN+4);
 		length = raf.read(buff);
 		strName = new String(buff,0,length);
 		System.out.println(strName.trim()+":"+raf.read());
 		
 		raf.seek(0); 
 		length = raf.read(buff);
 		strName = new String(buff,0,length);
 		System.out.println(strName.trim()+":"+raf.read());

		raf.skipBytes(Employee.LEN+4);
		length = raf.read(buff);
 		strName = new String(buff,0,length);
 		System.out.println(strName.trim()+":"+raf.read());

 		raf.close();
 	}
 }
 
 class Employee
 {
 	String name;
 	int age;
 	public static final int LEN=8;
 	public Employee(String name,int age)
 	{
 		if(name.length() > LEN)
 		{
 			name = name.substring(0,LEN);	
 		}
 		else
 		{
 			while(name.length() < LEN)
 			{
 				name += "\u0000";
 			}
 		}
 		this.name = name;
 		this.age  = age;
 	}
 }