randomaccessfiledemo.java

来自「一些基本的java程序源代码」· Java 代码 · 共 45 行

package randomaccess.file.randomaccessfiledemo;
import java.io.*;
import java.util.*;
import randomaccess.file.student.Student;
public class RandomAccessFileDemo {
	public static void main(String[] args) {
		Student[] students={	new Student("justin",90),
				new Student("momor",95),
				new Student("bush",88),
				new Student("cater",86)		};
		try{
			File file=new File(args[0]);
			RandomAccessFile randomAccessFile=new RandomAccessFile(file,"rw");
			for(int i=0;i<students.length;i++)
			{
				randomAccessFile.writeChars(students[i].getName());
				randomAccessFile.writeInt(students[i].getScore());
			}
			Scanner scanner=new Scanner(System.in);
			System.out.print("读取第几个数据？");
			int num=scanner.nextInt();
			randomAccessFile.seek((num-1)*Student.size());
			Student student=new Student();
			student.setName(readName(randomAccessFile));
			student.setScore(randomAccessFile.readInt());
			System.out.println("姓名："+student.getName());
			System.out.println("分数："+student.getScore());
			randomAccessFile.close();
		}
		catch(ArrayIndexOutOfBoundsException e){
			System.out.println("请指定文件名称");
		}
		catch(IOException e){
			e.printStackTrace();
		}
	}
	
	private static String readName(RandomAccessFile randomAccessfile)throws IOException{
		char[] name=new char[15];
		for(int i=0;i<name.length;i++)
			name[i]=randomAccessfile.readChar();
		return new String(name).replace('\0', ' ');
	}
}