http断点续传简单实现（java)

/* ]b0zkoD9<  
**SiteFileFetch.java c ,h.`~{  
*/ B&%L`v2
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package NetFox; f"ZqA'KB#  
import java.io.*; xVsa,EX b  
import java.net.*; LT,iS)dY+  
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public class SiteFileFetch extends Thread { g( ]b\rj  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]/aRc=Gn  
long[] nStartPos; //开始位置 "fX_gN?  
long[] nEndPos; //结束位置 i$`|Y*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P;)2*:--)  
long nFileLength; //文件长度 >~`Y
 
boolean bFirst = true; //是否第一次取文件 ]97Xu_  
boolean bStop = false; //停止标志 .iOw0z  
File tmpFile; //文件下载的临时信息 LKK{j,g7  
DataOutputStream output; //输出到文件的输出流 9_J!s  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） c*S#UD+  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5}-)vsa`  
{ 4B:\  
siteInfoBean = bean; &57qjA,8<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sowbg<D  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `!UaScM  
if(tmpFile.exists ()) vO}qjw  
{ t/v@vJ`vSH  
bFirst = false; nu4Pc  
read_nPos(); =,&u_>Dp  
} G]L0eV  
else ) >>u|#@z  
{ ^#a#<8Jz  
nStartPos = new long[bean.getNSplitter()]; VR
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nEndPos = new long[bean.getNSplitter()]; &%|xc{i  
} %-h7Z3YcN  
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} &_Cxv8  
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public void run() 6obQ9L c  
{ 7j@^+rkr3f  
//获得文件长度 LFEp  
//分割文件 /`7 IK  
//实例FileSplitterFetch E0sbU<11  
//启动FileSplitterFetch线程  )x$!K[=  
//等待子线程返回 ,3wI~j=  
try{ #rhVzN-?)W  
if(bFirst) a='IT 5  
{ #D!$~h&i  
nFileLength = getFileSize(); 20 jrv'f  
if(nFileLength == -1) S 3{Dn  
{ 7ZF}0K$^B  
System.err.println("File Length is not known!"); X?KGb{  
} Y h^WTysBn  
else if(nFileLength == -2) IL!BPFG w  
{ `y1BTe&  
System.err.println("File is not access!"); aj&\CJ  
} yQu vW$  
else `^O'V}T  
{ P/FrE~  
for(int i=0;i<nStartPos.length;i++) MB}:GY?  
{ .(`(chRa}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cj$,ob&DX  
} $@_
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for(int i=0;i<nEndPos.length-1;i++) l0gH(28K  
{ R!sNg   
nEndPos = nStartPos[i+1]; n (OjjRm  
} y.jS{r".  
nEndPos[nEndPos.length-1] = nFileLength; QH& %mr.S  
} 11i"n
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} 8&?^XcJ*x  
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//启动子线程 0w^jls  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; '"Bex`  
for(int i=0;i<nStartPos.length;i++) V%i<;C  
{ ZkwJ.SuU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PqTYAN&F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), b OW}"  
nStartPos,nEndPos,i); uEBQo
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YavfjS:2  
fileSplitterFetch.start(); K3La9O)>  
} +nU',E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Xfj)gPt}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); kBrvl^D{5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4#TnXxL  
nEndPos = " + nFileLength); #o"tMh!f  
// fileSplitterFetch[nPos.length-1].start(); J09*v)L  
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//等待子线程结束 6!*K/2:O  
//int count = 0; OMl8 a B9  
//是否结束while循环 0 9tikj1  
boolean breakWhile = false; |d5ggf.w  
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while(!bStop) C,[L/!  
{ P~&O4['<  
write_nPos(); ty':`)  
Utility.sleep(500); QyTh!QM~`  
breakWhile = true; h!QjpzQe  
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for(int i=0;i<nStartPos.length;i++) AlUJ1^o)  
{ ri,2clp  
if(!fileSplitterFetch.bDownOver) Xe)Pg)J1  
{ o\d |CE;>  
breakWhile = false; TV? ^c?{5  
break; g .3
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} $,!hD\a  
}
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if(breakWhile) ,Ie<'>hd  
break; tzZ|S<e6=\  
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//count++; &.hoCPo$  
//if(count>4) S 9WawI  
// siteStop(); Lg8]dBXu  
} D
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System.err.println("文件下载结束！"); DQcWq'yY^  
} 0(\p
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catch(Exception e){e.printStackTrace ();}
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} 
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//获得文件长度 ,dOMW+{  
public long getFileSize() u]R$]&<  
{ T{ok +$w2  
int nFileLength = -1; av$  
try{ nz>K{(  
URL url = new URL(siteInfoBean.getSSiteURL()); ) 9xX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V):`&@  
httpConnection.setRequestProperty("User-Agent","NetFox"); f;R>Pr;rD  
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int responseCode=httpConnection.getResponseCode(); Sq<3
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if(responseCode>=400)
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{ So?m?,!W  
processErrorCode(responseCode); ej<`CQ  
return -2; //-2 represent access is error :|=- (z  
} h5j<u  
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String sHeader; l4zw]AYk+X  
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for(int i=1;;i++) a"k'm}hVY$  
{ 6`1k ^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ekrBNDs9  
//Utility.log(in.readLine()); nYhp`!W4;  
sHeader=httpConnection.getHeaderFieldKey(i); 'w:bs!  
if(sHeader!=null) CNq[4T'~A  
{ 3XnE y +  
if(sHeader.equals("Content-Length")) # 9V'';:  
{ ZH!;z-R  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }H5/3be  
break; ZxI]I1)  
} V>
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} JfSdUWxT  
else ?x'w~;9R/  
break; ~C0Pu.{o  
} RFB(d=o5S  
}
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catch(IOException e){e.printStackTrace ();} >C:If0S4X  
catch(Exception e){e.printStackTrace ();} X`D+jiQ(f  
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Utility.log(nFileLength); )}quw"H  
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return nFileLength; f'i6QMk\&  
} v O PMgEI  
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//保存下载信息（文件指针位置） Qd?CTYNsv  
private void write_nPos() *N`;I@Q"[  
{ a/:]"`)  
try{ 1c/ X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K|Om5 p  
output.writeInt(nStartPos.length); tR5tPPw  
for(int i=0;i<nStartPos.length;i++) oikxg!0S  
{ Et.j1M|g  
// output.writeLong(nPos); ~oo'ky*H!  
output.writeLong(fileSplitterFetch.nStartPos);  J+lGh9G  
output.writeLong(fileSplitterFetch.nEndPos); /e .D/;]  
} %/Bvy*X&  
output.close(); 0lBat_<8  
} ^g[J*{+!W  
catch(IOException e){e.printStackTrace ();} i2`#   
catch(Exception e){e.printStackTrace ();}
}DbE4"^K7  
} 'd+
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//读取保存的下载信息（文件指针位置） 6W$rY] h!  
private void read_nPos() [1Uz_HY["3  
{ Ajg\aof0{  
try{ uS&LG#a  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0`6),R'x  
int nCount = input.readInt(); jAZ >mo[  
nStartPos = new long[nCount]; 1g~y]iQ  
nEndPos = new long[nCount]; A*Rn<{U  
for(int i=0;i<nStartPos.length;i++) o_(0  
{ v~f'K3fLp  
nStartPos = input.readLong(); <&6u]uKrW  
nEndPos = input.readLong(); 5=Suj*s{D#  
} y~dB5/  
input.close(); =tnTdp0F  
} zWb-pF|  
catch(IOException e){e.printStackTrace ();} JdO)YlM-  
catch(Exception e){e.printStackTrace ();} :pb67Al29  
} Qww^P/vm  
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private void processErrorCode(int nErrorCode) ~GA8_B  
{ &kiF/F 1  
System.err.println("Error Code : " + nErrorCode); >K5~:mx#3  
} w2C&%Xk  
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)@_ugW-j
 
//停止文件下载 |_, /u_  
public void siteStop() 0 7\02f  
{ ><K!~pst}  
bStop = true; ]Z/R!y?l"G  
for(int i=0;i<nStartPos.length;i++) "
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fileSplitterFetch.splitterStop(); @+:4J_N  
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} MUB37  
} r^Y~mq  
//负责部分文件的抓取 Ok*Z  
**FileSplitterFetch.java >T QZk4$  
*/ {\L|s5=yr  
package NetFox; @C=M UT-!  
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import java.io.*; u1N1n;#  
import java.net.*; ^aHh{
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public class FileSplitterFetch extends Thread { [Y$V\h=V  
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String sURL; //File URL -%H%m`wD  
long nStartPos; //File Snippet Start Position [IMQIX  
long nEndPos; //File Snippet End Position :/i~y$t  
int nThreadID; //Thread's ID r@yD8D \  
boolean bDownOver = false; //Downing is over ami09JHy  
boolean bStop = false; //Stop identical Dkw*Je#6PX  
FileAccessI fileAccessI = null; //File Access interface Z\'wm'  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Fg4@On[,i  
{ .it2NS  
this.sURL = sURL; n/AW?'  
this.nStartPos = nStart; 5 q65nF  
this.nEndPos = nEnd; >C# kqxfg  
nThreadID = id; cQn)^jx=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [
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} A="fj  
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public void run() k}U JVH21k  
{ h0lu!m#\_  
while(nStartPos < nEndPos && !bStop) `|?]CkP  
{ SM<d  
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try{ )2V@p~k?  
URL url = new URL(sURL); iadkH]w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z2bUs!0  
httpConnection.setRequestProperty("User-Agent","NetFox"); R8 jovr  
String sProperty = "bytes="+nStartPos+"-"; |xeE3,8  
httpConnection.setRequestProperty("RANGE",sProperty); #w*"qn#2Uz  
Utility.log(sProperty); :,^>d3k  
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InputStream input = httpConnection.getInputStream(); ;UpJ=?W  
//logResponseHead(httpConnection); Uouq>N  
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byte[] b = new byte[1024]; 5(#-)rlGj  
int nRead; si?HkJv5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W>/UBN3  
{ H(&Z:{L  
nStartPos += fileAccessI.write(b,0,nRead); t!t=|JNf{  
//if(nThreadID == 1) [O1|75  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CKd3w8;  
} (tKMBxQo8  
+ Kk@Q  
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Utility.log("Thread " + nThreadID + " is over!"); {g_@Tuu  
bDownOver = true; .`J:xL%Z  
//nPos = fileAccessI.write (b,0,nRead); GO~k '  
} <[<24
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catch(Exception e){e.printStackTrace ();} y 1nU{Sc@  
} #KE;=$(S  
} @ae
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//打印回应的头信息 u5F}(+4r  
public void logResponseHead(HttpURLConnection con) (3W&AM  
{ x5F@ad9  
for(int i=1;;i++) v|&s4x?D  
{ =<.F3lo\s  
String header=con.getHeaderFieldKey(i); D:m#d.m  
if(header!=null) 'HB~Dbq`V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /[?Jylj  
Utility.log(header+" : "+con.getHeaderField(header)); &O*ENpF  
else
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break; w+=Q6]FxJ  
} [b;Uz|o  
} -l[jEJS}  
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public void splitterStop() @n@g)`  
{ VYigxhP7  
bStop = true; _lT0Hu  
}  5~s{N  
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} wT/6aJoX  
]/44Ygz/  
@|=UrKAN  
/* Bc[6*Y,%T  
**FileAccess.java W>$BF[x!{  
*//文件访问(定位，写) [pR)@$"k'  
package NetFox; "teyi"U+  
import java.io.*; 
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public class FileAccessI implements Serializable{ Spo+@G  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9wMEvX70  
RandomAccessFile oSavedFile; a(|xw  
long nPos; sg$4G:l  
[#Fg\2bq_y  
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public FileAccessI() throws IOException rS,j;8D-  
{ N
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this("",0);
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} t'aSF{%  
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public FileAccessI(String sName,long nPos) throws IOException ?K<ZkYw?  
{ ?Pnx~m{%*  
oSavedFile = new RandomAccessFile(sName,"rw"); ^IgS  
this.nPos = nPos; :H\&2/j  
oSavedFile.seek(nPos); :~33U)?{T  
}  f`J|>Vk  
= t-fYV  
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public synchronized int write(byte[] b,int nStart,int nLen) +6376$dC  
{ pL)xqKj  
int n = -1; @H+~2;B,  
try{ 9[sG1eP!  
oSavedFile.write(b,nStart,nLen); nsl*Dm"*F  
n = nLen; 9A+M|;O  
} 9GPb$gtx  
catch(IOException e) j{"[Ec  
{ "Z~`e]>  
e.printStackTrace (); Pw xIz  
} h!Y?SO.b  
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return n; |*E"G5WZM  
} ~d>uXrb  
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} T3rn+BxF7  
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/* Y%h}U<y  
**SiteInfoBean.java |Ng"C`$oqv  
*/ uS-3\$  
package NetFox; 6F-JK1i  
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public class SiteInfoBean { pns+y  
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private String sSiteURL; //Site's URL ob]dZ  
private String sFilePath; //Saved File's Path ] R<FKJ[  
private String sFileName; //Saved File's Name 2Y;!$0_rv  
private int nSplitter; //Count of Splited Downloading File Aqu]9M~  
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public SiteInfoBean() M5 `m.n<  
{//nSplitter的缺省值为5 >fbo r'|  
//default value of nSplitter is 5 Qg>0G%cXU  
this("","","",5); 4Cd#sQ  
} QPV@'.2m  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) zLK\I~rU!  
{ `VXZ khm  
sSiteURL= sURL; */Cj$KY70  
sFilePath = sPath; 7t3X`db  
sFileName = sName; ^r4|{  
this.nSplitter = nSpiltter; iN`6xkY  
0 {,h.:  
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} GmAj</~  
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public String getSSiteURL() O8[k_0@  
{ 6y9C@5p}B  
return sSiteURL; u?Z <n:  
} `I{tZ$iD  
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1
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public void setSSiteURL(String value) [,GU5,o  
{ b"&E,=L  
sSiteURL = value; y<v|X2  
} T g{UK  
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public String getSFilePath() yXrd2?Rq@  
{ f,JX"  
return sFilePath; on_H6Y@B52  
} 3t*#!^$  
*:[b'D!A  
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public void setSFilePath(String value) 5pmQp}}R  
{ o~k;D{Snr  
sFilePath = value; vS#{-X  
} @ge LW!  
]/[0O+B?  
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public String getSFileName() ]K*GSU  
{ }b
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return sFileName; >+SZd7p  
} >"b[r  
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public void setSFileName(String value) 'mUI-1GkT  
{ jNIUsM8e  
sFileName = value; j6}$+!E  
} ~M; gM]r;  
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public int getNSplitter() h&P {p _Y  
{ 4a?r` '  
return nSplitter; #?Wo <]i  
} 1EuK,:x  
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public void setNSplitter(int nCount) 9':/Sab:7v  
{ 2n(ItA  
nSplitter = nCount; H<XlUCr_~+  
} E)Srj~$d  
} Z>&K&ttJ  
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/* fSr`>UpxC  
**Utility.java k5C>_( A  
*/ TGtyJ3x\  
package NetFox; ^7<[}u;qF  
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public class Utility { YMK>+y[+4  
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public Utility() m3B\)2B  
{ {RH*8?7  
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@EYK(QS-  
} (]}XLMi,|!  
4[Z1r~t\L  
//线程睡眠 QY@nE  
public static void sleep(int nSecond) j $KM9  
{ "s${!A)  
try{ Ir^BC!<2>  
Thread.sleep(nSecond); ^h`!f vyH  
} dw3'T4TC?  
catch(Exception e) bYK]G+Ww  
{ hg{ &Y(J!U  
e.printStackTrace (); @ E >eq.m  
} 0T=jR{j!o  
} unpfA#&!"  
O4n8MM|`  
//日志 ]2P/G5C3tU  
public static void log(String sMsg) #c:9V2  
{ 1BTgGF  
System.err.println(sMsg); "AV1..mu  
} a~6ztEhGm  
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public static void log(int sMsg) 9W$mDw6f  
{ E $<;@  
System.err.println(sMsg); w9'H.Lq  
} {Qm6?H  
} ?F9hDLX  
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/* EmF]W+!z%  
**TestMethod.java FW/)uf3I  
*/ A<a2TXcIE3  
package NetFox; [GOX0}$?  
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public class TestMethod { #%;<FFu\  
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public TestMethod() UP5%C;  
{ ///xx/weblogic60b2_win.exe ^GrNfB[Qu  
try{ xu`d`!Tx  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Vvxa.B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'T6B_9GQ8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Feh"!k <6k  
fileFetch.start(); </8be=e7p  
} {V{0^T-  
catch(Exception e){e.printStackTrace ();} ,o4r,.3[s  
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} SIj
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public static void main(String[] args) h 3eGq:!9  
{ zsHG=Ee*  
new TestMethod(); ](]*]a4ss  
} ;L#LDk{Za  
} zojuH8  
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