decompress.java~1~

用java编写的压缩程序

package compress;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.io.ObjectInputStream;
import java.io.RandomAccessFile;
import java.util.Calendar;


public class DeCompress extends Thread{

	/**
	 * @param args
	 */
	//Test testor;
	String codeChar;
	String code;
	String text;
	String remain;
	String textFile,codeFile;
public	long filelength;
public	double currentlength;
//	public static void main(String[] args) {
//		// TODO Auto-generated method stub
//		DeCompress decomer=new DeCompress();
//		 Calendar cal=Calendar.getInstance();
//	      System.out.println("Start Time: "+cal.get(Calendar.HOUR_OF_DAY)+":"+cal.get(Calendar.MINUTE)+":"+cal.get(Calendar.SECOND)+":"+cal.get(Calendar.MILLISECOND));
//
//		decomer.deCompress("e://test.dat", "e://testresult.txt");
//		cal=Calendar.getInstance();
//	      System.out.println("End Time: "+cal.get(Calendar.HOUR_OF_DAY)+":"+cal.get(Calendar.MINUTE)+":"+cal.get(Calendar.SECOND)+":"+cal.get(Calendar.MILLISECOND));
//	}
	public DeCompress(){
		this.initialize();
	}
	public DeCompress(String codeFile,String textFile){
		this();
		this.setFile(codeFile, textFile);
	}
	public void setFile(String codeFile,String textFile){
		this.codeFile=codeFile;
		this.textFile=textFile;
	}
void initialize(){
	codeChar=code=text=remain="";
}
/*
 * 把String 串转化为01代码
 *
 */
String ConvertCharToBits(String chars){
	String result="";
	for(int i=0;i<chars.length();i++){
	int number=(int)chars.charAt(i);
	  //covernt number to bits
	  while(number!=0){
		  //对number除2取余，如果余数是1，就在result前 添加1，如果余数是零就在result前添加0
		  if(number%2==0)
			  result="0"+result;
		  else //number%2==1
			  result="1"+result;
		  number=number/2;
	  }
	  number=result.length()%16;
	  if(number!=0){
		  for(int t=0;t<16-number;t++)
			  result="0"+result;
	  }
	}
	  return result;
}
String ConvertCharToBits(char cha){
	  String result="";
	 int count=0;
	  //先把char转化为整数
	  int number=(int)cha;
	  //System.out.print(number+"  ");
	  //把整数通过取模运算转化成01代码
	  while(number!=0){
		  if(number%2==0)
			  result="0"+result;
		  else //number%2==1
			  result="1"+result;
		  number=number/2;
	  }
	  count=result.length();
	  if(count<16){
		  for(int i=0;i<16-count;i++)
			  result="0"+result;
	  }

	  return result;
}
String ConvertIntToBits(int number){
	String result="";
	 int count=0;
	  //先把char转化为整数

	  //System.out.print(number+"  ");
	  //把整数通过取模运算转化成01代码
	  while(number!=0){
		  if(number%2==0)
			  result="0"+result;
		  else //number%2==1
			  result="1"+result;
		  number=number/2;
	  }
	  count=result.length();
	  if(count<16){
		  for(int i=0;i<16-count;i++)
			  result="0"+result;
	  }

	  return result;

}
String ConvertByteToBits(byte num){
	String result="";
	 int count=0;
	  //先把char转化为整数
	int number=num;
	  //System.out.print(number+"  ");
	  //把整数通过取模运算转化成01代码

	  while(number!=0){
		  if(number%2==0)
			  result="0"+result;
		  else //number%2==1
			  result="1"+result;
		  number=number/2;
	  }
	  count=result.length();
	  if(count<8){
		  for(int i=0;i<8-count;i++)
			  result="0"+result;
	  }

	  return result;

}
String decode(String codes, CodeNode[] map) {
    //根据字符映射表把原文件解压缩
    int p = 0;
    String result = "";

    codes=remain+codes;

    for (int i = 0, n = 0; i <= codes.length() && n <= codes.length(); n++)

    {
        String temp = codes.substring(i, n);
        for (int j = 0; j < map.length; j++) {
            if (map[j].code.equals(temp)) { //将结果字符保存在char数组res中
                result += map[j].cha;
                p++;
                i = n; //改向搜索下一个编码
            }
        }
        remain=codes.substring(i,codes.length());
    }

    return result;
}
public void deCompress(String codeFile,String textFile){
	File cFile = new File(textFile);
	if(cFile.exists())
	{//删除重名文件
	cFile.delete();
	}

	  PrintWriter writer = null;
	  CodeNode[] map;//字符映射表
	  char cha;
	  String temp="";
	  FileInputStream input;//文件流
	  DataInputStream in ;
	  ObjectInputStream objectReader;//读对象
	  RandomAccessFile randomReader;
	  String[] lines;
	  try{
		  input=new FileInputStream(codeFile);//建立读文件的流
		  in = new DataInputStream(input);//读字符数据
		  objectReader=new ObjectInputStream (input);//建立度对象的流
		  randomReader=new RandomAccessFile(codeFile,"rw");//建立随机读取流
		  filelength=randomReader.length(); //获得文件长度
		  randomReader.seek(filelength-4);	 //定位到最后的int 值之前
		  int leafsLength=randomReader.readInt();//读取对象个数
		 // System.out.println(leafsLength);
		  randomReader.seek(filelength-8);
		  int actualBitsLength=randomReader.readInt();//读取最后一串01的实际长度
		  //System.out.println(actualBitsLength);
		  randomReader.close();//到此为止，已经不再需要randomReader类，close it
		 // System.out.println("Codes: "+leafsLength);
		  map=new CodeNode[leafsLength];
		  for(int i=0;i<map.length;i++){
			  map[i]=(CodeNode)objectReader.readObject();//读取字符映射表
		  }
	       writer = new PrintWriter(new FileOutputStream(textFile,true));
	         while(currentlength<this.filelength-10){
	        	 //10=最后一个字符:2+ 最后一个01串的实际长度(int):4+对象的数目(int):4
		    	this.currentlength+=2;//当前已经处理了多少
		    	cha=in.readChar();
		    	//if(cha==-1) break;
		    	this.code=this.ConvertCharToBits(cha);//把字符转化为01
		    	this.text=this.decode(this.code, map);//把01解压为文本
		        text=temp+text;
		    	lines=this.text.split("\n");
		    	if(text.endsWith("\n")){
		    	for(int i=0;i<lines.length;i++)
		    	writer.println(lines[i]);
		    	temp="";
		    	}
		    	else {
		    		 // System.out.println("Codes below this line must throw IOException");

		    		for(int i=0;i<lines.length-1;i++){
		    		writer.println(lines[i]);
		    		//System.out.println(i+" "+lines[i]);
		    		}
		    		temp=lines[lines.length-1];//保存上次未写完的字符串
		    		}
		   }
	        // System.out.println("Codes below this line must throw IOException");
	         String lastBits="";
	         if(actualBitsLength>0){
	        	 //如果有剩余的01串，那么读出来
	         char lastOne=in.readChar();
	         lastBits=this.ConvertCharToBits(lastOne);
	         lastBits=lastBits.substring(16-actualBitsLength,16);//得到最后一串01
	         }
	         lastBits=remain+lastBits;//在前面添加上次没处理的01
	         if(lastBits.length()>0){
	         this.text=this.decode(lastBits, map);//得到最后的文本
	         text=temp+text;//把上次未写入文件的字符串写入文件
	         writer.println(text);}
                 input.close(); //close FileInput Stream

    }
	 catch(IOException io){

	 System.out.println(io.getLocalizedMessage());
		 // System.out.println(io.getMessage());
  }
	  catch(ClassNotFoundException cnf){
		  System.err.println("Can't Find the class! "+cnf.getLocalizedMessage());
	  }
	  finally{
		  //this.currentlength+=10;
                  this.currentlength=this.filelength;
                  writer.close();

	  }
}
public void run(){//重写run方法
	if(this.textFile==null||this.codeFile==null){
		System.err.println("Can't get the filename");
	}
	else {
		this.deCompress(codeFile, textFile);
	}

}
}