dealcomment.java

一个java写的面向对象流的简单的文件系统,理论研究的吧

package dealcomment;
/*
 *do by jjl2009 3.6
 *
 **/
import java.io.*;
import java.util.*;
import active.*;
class dealComment {
//	File cHead;
	File aCmmt;
///	RandomAccessFile rafH;
	RandomAccessFile rafC;
	public static final int READ=0;
	public static final int WRITE=1;
	int flag;
	String cmtUrl;
	Vector vCmtBuf=new Vector();
	int size=0;
public dealComment(String fileCmt,int flag){
	this.flag=flag;
	cmtUrl=fileCmt;
		try{
		//	cHead=new File(fileCmt+".chd");
			aCmmt=new File(fileCmt);
			if(flag==WRITE){
			/*	if(!cHead.exists()){
				System.out.println("活动评论的头文件不存在！新创建中.....");
				cHead.createNewFile();
				}*/
				if(!aCmmt.exists()){
					System.out.println("活动评论不存在创建中.....");
					aCmmt.createNewFile();
				}
			}else{
			/*	if(!cHead.exists()){
				System.out.println("活动评论的头文件不存在！读取失败");
				return;
				}*/
				if(!aCmmt.exists()){
					System.out.println("活动评论不存在读取失败！");
					return;
				}
			}
		//	rafH=new RandomAccessFile(cHead,"rw");
			rafC=new RandomAccessFile(aCmmt,"rw");
			rafC.seek(0);
			rafC.writeLong(16);
			rafC.writeLong(16);
		}catch(Exception e){
			System.out.println(e);
			System.out.println("初始化失败！");
		}
	}
	
	public void setComment(Comment comment){
		try{
		if(rafC==null){
			rafC=new RandomAccessFile(aCmmt,"rw");
		}
		System.out.println("...........尝试添加评论在活评论文件"+cmtUrl+"...........");
		rafC.seek(8);
		Long hp=rafC.readLong();
		rafC.seek(hp);
		rafC.writeUTF(comment.getActiveName());
		rafC.writeUTF(comment.getPerson());
		rafC.writeUTF(comment.getTime());
		rafC.writeUTF(comment.getContent());
		Long p=rafC.getFilePointer();
		rafC.seek(8);
		rafC.writeLong(p);
		}catch(Exception e){
			System.out.println("添加活动评论出现故障！");
		}
	}
	public void close(){
		if(rafC!=null){
			try{
				rafC.close();
				rafC.seek(0);
				rafC.writeLong(16);
			}catch(Exception e){
				System.out.println("关闭文件时出错了！");
			}
			
		}
	}
	public Comment getNextComment(){
		if(rafC==null)return null;
		Comment comment=new Comment();
		try{
			rafC.seek(0);
			Long p1=rafC.readLong();
		//	if(p1==rafC.readLong())return null;
			System.out.println("正在读取位置为："+p1+"的内容");
			rafC.seek(p1);
			comment.setActiveName(rafC.readUTF());
			comment.setPerson(rafC.readUTF());
			comment.setTime(rafC.readUTF());
			comment.setContent(rafC.readUTF());
			Long p=rafC.getFilePointer();
			rafC.seek(0);
			rafC.writeLong(p);
			return comment;
		}catch(Exception e){
			System.out.println("获取下一评论时失败！");
			return null;
		}
	}
	public static void main(String args[]){
		dealComment dealC=new dealComment("name.cmt",dealComment.WRITE);
		Comment comment=new Comment();
		comment.setActiveName("jjl");
		comment.setTime("20092");
		comment.setPerson("ff");
		comment.setContent("fff");
		dealC.setComment(comment);
		comment.setActiveName("jjl11");
		comment.setTime("20092");
		comment.setPerson("ff");
		comment.setContent("fff");
		dealC.setComment(comment);
		dealComment dealCm=new dealComment("name.cmt",dealComment.READ);
		comment=dealCm.getNextComment();
		if(comment!=null)
		System.out.println(comment.getActiveName());
		comment=dealCm.getNextComment();
		if(comment!=null)
		System.out.println(comment.getActiveName());
	}
}