server.java

实验服务端与服务端的传送文件的功能~可以是文档格式

import java.io.FileOutputStream; 
import java.net.DatagramPacket; 
import java.net.DatagramSocket; 
import java.util.Iterator; 
import java.util.Map; 
import java.util.TreeMap; 
import java.util.Map.Entry; 
class DataStruct { 
    // 文件的id，十位，多文件同時傳送時用來區分不同的文件 
    public String fileId; 

    // 包的序號 
    public int index; 

    // 包中有效數據的長度 
    public int len; 

    // 包 
    public byte[] data; 

    // 解析包內容 
    public DataStruct(byte[] data) { 
        fileId = new String(data, 0, 10); 
        index = (data[10] & 0x000000FF) | (data[11] << 8 & 0x0000FF00) 
                | (data[12] << 16 & 0x00FF0000) | data[13] << 24 & 0xFF000000; 
        len = (data[14] & 0x000000FF) | (data[15] << 8 & 0x0000FF00) 
                | (data[16] << 16 & 0x00FF0000) | data[17] << 24 & 0xFF000000; 
        this.data = data; 
    } 
    	} 

//Server: 

//Server: 
//--------------------------------------------------------------------- 


public class Server { 
    public static void main(String[] args) { 
        try { 
            DatagramSocket reciveSocket = new DatagramSocket(7774); 
            ProcData proc = new ProcData(); 
            byte[] buf = new byte[50 * 1024]; 
            DatagramPacket dp = new DatagramPacket(buf, 50 * 1024); 
            while (true) { 
                reciveSocket.receive(dp); 
                proc.proc(dp); 
            } 
        } catch (Exception e) { 
            // TODO: handle exception 
        } 
    } 
} 

class ProcData { 
    private FileOutputStream fos; 

    Map<Integer, DataStruct> packBuf = new TreeMap<Integer, DataStruct>(); 

    int nextIndex = 1; 

    DatagramSocket sendSocket; 

    public ProcData() { 
        try { 
            fos = new FileOutputStream("c:/1.bmp"); 
            sendSocket = new DatagramSocket(); 
        } catch (Exception e) { 
            System.out.println("error in new ProcData()"); 
        } 
    } 

    public void proc(DatagramPacket dp1) { 
        DataStruct data = new DataStruct(dp1.getData()); 

        if (data.index == nextIndex) { 
            try { 
                // 序號是下一個序號，寫文件 
                nextIndex++; 
                fos.write(data.data, 18, data.len); 
                // 處理緩衝中的內容 
                Iterator<Entry<Integer, DataStruct>> iter = packBuf.entrySet() 
                        .iterator(); 
                while (iter.hasNext()) { 
                    data = iter.next().getValue(); 
                    if (data.index == nextIndex) { 
                        nextIndex++; 
                        fos.write(data.data, 18, data.len); 
                    } 
                } 
            } catch (Exception e) { 
                e.printStackTrace(); 
            } 
        } else if (data.index > nextIndex) { 
            // 如果序號大於應當接收的序號，則保存在緩衝中.... 
            // TODO: 如果某一序號的包很久都沒有傳過來，則需要發消息到客 戶端，要求從新發送 
            packBuf.put(data.index, data); 
        } 
    } 
}