java中RandomAccessFile种用法

RandomAccessFile类
    只能访问文件，不能操作其他io设备
    支持随机访问
    在读写等长记录文件有优势

实例：

import java.io.*;class Employee {	private String name;	private int age;	public static final int LEN = 8;		String getName() {		return name;	}		int getAge() {		return age;	}		Employee(String name, int age) {		if (name.length() > LEN) { // 为了构造等长记录			this.name = name.substring(0, LEN-1);		} else {			this.name = name;			while (this.name.length() < LEN) {				this.name += '\u0000';			}		}		this.age = age;	}}public class RandomAccessFileTest {	public static void main(String [] args) {		Employee e1 = new Employee("Ronnie", 37);		Employee e2 = new Employee("John", 37);		Employee e3 = new Employee("Mark", 37);				try {			RandomAccessFile randFile = new RandomAccessFile("employee.txt", "rw");						//randFile.write(e1.getName().getBytes()); // 如果name有中文，会出现问题，因为一个英文字符转换为一个字节，一个中文字符转换为两个字节，可以用writeChars函数改写			randFile.writeChars(e1.getName()); //-			randFile.writeInt(e1.getAge());			//randFile.write(e2.getName().getBytes());			randFile.writeChars(e1.getName()); //-			randFile.writeInt(e2.getAge());			//randFile.write(e3.getName().getBytes());			randFile.writeChars(e1.getName()); //-			randFile.writeInt(e3.getAge());						randFile.close();		} catch (Exception e) {			e.printStackTrace();		}				try {			//byte[] nameBuf = new byte[Employee.LEN];						RandomAccessFile randFile = new RandomAccessFile("employee.txt", "r");						//randFile.skipBytes(12);			randFile.skipBytes(20); //-			//int len = randFile.read(nameBuf);			//String name = new String(nameBuf, 0, len);			String name = "";//-			for (int i = 0; i < Employee.LEN; ++i) { //-				name += randFile.readChar(); //-			}//-			System.out.println(name.trim() + ":" + randFile.readInt());			name = ""; //-						randFile.seek(0); // 绝对定位			//len = randFile.read(nameBuf);			//name = new String(nameBuf, 0, len);			for (int i = 0; i < Employee.LEN; ++i) { //-				name += randFile.readChar(); //-			} //-			System.out.println(name.trim() + ":" + randFile.readInt());			name = ""; //-						//randFile.skipBytes(12);			randFile.skipBytes(20); //-			//len = randFile.read(nameBuf);			//name = new String(nameBuf, 0, len);			for (int i = 0; i < Employee.LEN; ++i) { //-				name += randFile.readChar(); //-			} //-			System.out.println(name.trim() + ":" + randFile.readInt());						randFile.close();		} catch (Exception e) {			e.printStackTrace();		}	}}

注释部分为按字节写入时的程序，带//-为原来的代码

其他函数请参照jdk文档