滑动窗口协议实现疑问
用java实现滑动窗口协议，就是先读一个文件，把他传到一个数据结构里，然后读出来，然后发送acknowledgement，然后在发送一段，比如0 ， 7 ，5，6，8，9，1 定义窗口大小如果是3的话，传到第三次就是一个循环，我现在的问题是只能传一次，不知道怎么收到acknowledgement了，用的是java io包的fileinputstream我的代码如下，请高手指点一下改怎么改进一下，想了好久了还是不行，谢谢！import java.util.*;
import java.io.*;
class Frames{
String type;
int sequenceNo;
int datasize;
byte data[];
public Frames(String t,int s,byte[] d){
type = t;
sequenceNo = s;
data = d;
}
public String gettype(){
return type;
}
public int getsequenceNo(){
return sequenceNo;
}
public int getdatasize(){
return datasize;
}
public byte[] getdata(){
return data;
}
}
class Send implements Runnable{
Frames inframe;
Frames ackframe;
String s;
Buffer<Frames> buffer;
Vector<Frames> iframe ;
Vector<Frames> aframe ;
int nextStart=0;
int windowStart=0;
int windowEnd;
int sequenceN;
byte a[] = new byte[10];
File f=new File("D:\\s\\test.txt");
FileInputStream in =null;
public Send(Buffer<Frames> b,Vector<Frames> iframe,Vector<Frames> aframe){
buffer = b;
this.iframe = iframe;
this.aframe = aframe;
}
public void run(){
try{
in = new FileInputStream(f);
}catch(FileNotFoundException e1){
System.out.println("can not find file");
System.exit(-1);
}
try{
in.read(a);
}catch(IOException e2){
System.out.println("fail");
System.exit(-1);
}
int windowEnd=(windowStart+(buffer.windowsize)-1)%(buffer.windowsize);
while(nextStart>=windowStart&&nextStart<windowEnd){
sequenceN = nextStart;
inframe = new Frames("Information",sequenceN,a);
System.out.println("Creat "+sequenceN+""+inframe.gettype()+" frame");
nextStart=nextStart+1;
buffer.put(inframe);
System.out.println("Send NO."+sequenceN+" frame");
}
try{
in.close();
}catch(IOException e3){}
try{
Thread.sleep(2000);
}catch(InterruptedException ea){}
}
}
class Receive implements Runnable{
byte c[];
Frames inframe;
Frames ackframe;
String s;
Buffer<Frames> buffer;
Vector<Frames> iframe;
Vector<Frames> aframe;
int windowStart=0;
int windowEnd;
int nextStart=0;
int ackN;
File f = new File("D:\\s\\new.txt");
FileOutputStream out = null;
public Receive(Buffer<Frames> b,Vector<Frames> iframe,Vector<Frames> aframe){
buffer = b;
this.iframe = iframe;
this.aframe = aframe;
}
public void run(){
try{
out = new FileOutputStream(f);
}catch(FileNotFoundException e){
System.out.println("fail");
System.exit(-1);
}
int windowEnd=(windowStart+(buffer.windowsize)-1)%(buffer.windowsize);
while(nextStart>=windowStart&&nextStart<windowEnd){
ackN=nextStart;
ackframe = buffer.get();
System.out.println("Recevie NO."+ackN+" frame");
nextStart=nextStart+1;
c = buffer.get().getdata();
try{
out.write(c);
}catch(IOException e2){}
}
try{
out.close();
}catch(IOException ea){}
}
}
class Buffer<Frames>{
Vector<Frames> iframe;
Vector<Frames> aframe;
public int windowsize;
private int size = 0;
public Buffer(Vector<Frames> iframe, Vector<Frames> aframe,int w){
this.iframe=iframe;
this.aframe=aframe;
windowsize = w;
}
synchronized void put(Frames f){
while(size == windowsize){
try{
wait();
}
catch(InterruptedException e){}
}
iframe.add(f);
size++;
if(size == 0)notify();
}
synchronized Frames get(){
while(size == 0){
try{
wait();
}
catch(InterruptedException e){}
}
Frames temp = iframe.get(0);
iframe.remove(0);
size--;
if(size==windowsize)notify();
return temp;
}
}
public class Assignment{
public static void main(String args[]){
Scanner input = new Scanner(System.in);
System.out.println("Please enter the size of window");
int t =input.nextInt();
Vector<Frames> i = new Vector<Frames>();
Vector<Frames> a = new Vector<Frames>();
Buffer b=new Buffer(i,a,t);
new Thread(new Send(b,i,a)).start();
new Thread(new Receive(b,i,a)).start();
}
}
----------------解决方案--------------------------------------------------------
不太明白楼主想实现什么
----------------解决方案--------------------------------------------------------
网络第二层，datalink layer，flow control， sliding windows protocol的功能！
----------------解决方案--------------------------------------------------------
我这里有材料
求助了，搞了一个月了，还是不行！
----------------解决方案--------------------------------------------------------
没有看明白
----------------解决方案--------------------------------------------------------
----------------解决方案--------------------------------------------------------
求助，我改进了代码，简单了，但是无法运行到底，就是简单的生产者消费者问题，我理解为，但是的发了6个数据只能收到3个，有人帮我看看代码吗？
import java.util.*;
import java.io.*;
class Frames{
String type;
int sequenceNo;
int datasize;
byte data[];
public Frames(String t,int s,byte[] d){
type = t;
sequenceNo = s;
data = d;
}
public String gettype(){
return type;
}
public int getsequenceNo(){
return sequenceNo;
}
public int getdatasize(){
return datasize;
}
public byte[] getdata(){
return data;
}
}
class Send implements Runnable{
Frames inframe;
Frames ackframe;
String s;
Bufferframe buffer;
int nextStart=0;
int windowStart=0;
int windowEnd;
int sequenceN;
byte a[] = new byte[100];
File f=new File("D:\\s\\new.jpg");
FileInputStream in =null;
public Send(Bufferframe b){
buffer = b;
}
public void run(){
try{
in = new FileInputStream(f);
}catch(FileNotFoundException e1){
System.out.println("can not find file");
System.exit(-1);
}
try{
in.read(a);
}catch(IOException e2){
System.out.println("fail");
System.exit(-1);
}
//int windowEnd=(windowStart+(buffer.windowsize)-1)%(buffer.windowsize);
// while(nextStart>=windowStart&&nextStart<windowEnd)
for(int k =0;k<buffer.windowsize;k++){
sequenceN = nextStart;
inframe = new Frames("Information",sequenceN,a);
System.out.println("Creat "+sequenceN+""+inframe.gettype()+" frame");
nextStart=nextStart+1;
buffer.put(inframe);
System.out.println("Send NO."+sequenceN+" frame");
}
try{
in.close();
}catch(IOException e3){}
}
}
class Receive implements Runnable{
byte c[];
Frames inframe;
Frames ackframe;
String s;
Bufferframe buffer;
int windowStart=0;
int windowEnd;
int nextStart=0;
int ackN;
File f = new File("D:\\s\\q.jpg");
FileOutputStream out = null;
public Receive(Bufferframe b){
buffer = b;
}
public void run(){
try{
out = new FileOutputStream(f);
}catch(FileNotFoundException e){
System.out.println("fail");
System.exit(-1);
}
//int windowEnd=(windowStart+(buffer.windowsize)-1)%(buffer.windowsize);
//while(nextStart>=windowStart&&nextStart<windowEnd)
for(int k=0;k<buffer.windowsize;k++){
ackN=nextStart;
ackframe = buffer.get();
System.out.println("Recevie NO."+ackN+" frame");
nextStart=nextStart+1;
c = buffer.get().getdata();
try{
out.write(c);
}catch(IOException e2){}
}
try{
out.close();
}catch(IOException ea){}
}
}
class Bufferframe{
public int windowsize=6;
public int index = 0;
Frames[] arr = new Frames[windowsize];
synchronized void put(Frames f){
while(index == arr.length){
try{
this.wait();
}
catch(InterruptedException e){}
}
this.notify();
arr[index]=f;
index++;
}
synchronized Frames get(){
while(index == 0){
try{
this.wait();
}
catch(InterruptedException e){}
}
this.notify();
index--;
return arr[index];
}
}
public class Assignment{
public static void main(String args[]){
Scanner input = new Scanner(System.in);
// System.out.println("Please enter the size of window");
// int t =input.nextInt();
Bufferframe b=new Bufferframe();
new Thread(new Send(b)).start();
new Thread(new Receive(b)).start();
}
}
----------------解决方案--------------------------------------------------------
为什么会数据丢失？
----------------解决方案--------------------------------------------------------
还有怎么施行大循环把数据全部传玩，求助了，我在北欧现在是早上2点不到，太累了想不出了，懂的帮我看看把，谢谢了！
----------------解决方案--------------------------------------------------------
每次发送或者读取的时候,应该在明确发送了多少,读入了多少,而并不是一个简单的read就完了,你要知道read的返回值是多少,因为这不一定能全部读满你的缓冲区
----------------解决方案--------------------------------------------------------