http断点续传简单实现（java)

/* 74OM tLL$  
**SiteFileFetch.java a6#PZ!1  
*/ ^aoLry&i=  
package NetFox; 6Ky"4\e  
import java.io.*; ?wY.B  
import java.net.*; ar}759  
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public class SiteFileFetch extends Thread { MUl+Oy>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean sVnuSm  
long[] nStartPos; //开始位置 #nhAW  
long[] nEndPos; //结束位置 g?M69~G$:x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #| Po&yu4R  
long nFileLength; //文件长度 +rX,Sl`/  
boolean bFirst = true; //是否第一次取文件 Xy<KvFy  
boolean bStop = false; //停止标志 xKux5u_  
File tmpFile; //文件下载的临时信息 J[AgOUc  
DataOutputStream output; //输出到文件的输出流 l<6/ADuS  
Y{@[)M{<  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %syBm  
public SiteFileFetch(SiteInfoBean bean) throws IOException L+CSF ]  
{ *?'T8yf^  
siteInfoBean = bean; "YZ`g}sG  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); nQ6'yd"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); y~[So ,G  
if(tmpFile.exists ()) *k$&Hcr$  
{ ~?r6Ax-R  
bFirst = false; $!@f{9+
 
read_nPos(); "de:plMofy  
} HOG7||&y  
else Kwnu|8  
{ DdgFBO  
nStartPos = new long[bean.getNSplitter()]; h]$zub
 
nEndPos = new long[bean.getNSplitter()]; /#5ZP\e  
} WI3!?>d  
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} w6 .HvH-@?  
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public void run() 1[ Pbsb  
{ #>'0C6Xn  
//获得文件长度 yfrgYA  
//分割文件 @ XMC$s  
//实例FileSplitterFetch oJy/PR3  
//启动FileSplitterFetch线程 z_)$g=9$  
//等待子线程返回 kOO2 ?L|Z  
try{ "'L SLp  
if(bFirst) 2]wh1)  
{ ]&>)=b!,  
nFileLength = getFileSize(); &s5*akG  
if(nFileLength == -1) Y*f<\z(4  
{ 8iRQPV-"_  
System.err.println("File Length is not known!"); Tj:F Qnx  
} B7;MY6h#  
else if(nFileLength == -2) dXhV]
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{  "(xu  
System.err.println("File is not access!"); \b->AXe8  
} *h1@eJHMz  
else )U` c9*.  
{ |u[gI+TUE  
for(int i=0;i<nStartPos.length;i++) rxA<\h,A  
{ P^UcpU,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7w|s8B  
} nYY U  
for(int i=0;i<nEndPos.length-1;i++) j#,O,\  
{ _"=~aMXC.)  
nEndPos = nStartPos[i+1]; e_SlM=_u  
} _+i-)  
nEndPos[nEndPos.length-1] = nFileLength; Uka4iya  
} 9z#IdY$a  
} ]@EjKgs  
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//启动子线程 Q
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (@zn[Nq  
for(int i=0;i<nStartPos.length;i++) %{Gqhb=u\  
{ 5"+* c@L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a%kj)ah  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S1."2AxO  
nStartPos,nEndPos,i); s*;~CH-[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UOyP6ej  
fileSplitterFetch.start(); U4
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} 8wOr`ho B  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]?2AFkF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); B(~D*H2T[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %2.T1X%!  
nEndPos = " + nFileLength); 1D$k:|pP~  
// fileSplitterFetch[nPos.length-1].start(); n(L {2r  
I('l)^m%  
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//等待子线程结束 =vWnqF:  
//int count = 0; ^U1;5+2G+~  
//是否结束while循环 shD$,! k  
boolean breakWhile = false; |Z<adOg  
-v:Y\=[\  
${?Px c{-  
while(!bStop) qQb8K+t  
{ ;-3M  
write_nPos(); W$y?~2  
Utility.sleep(500); aPbHrk*/  
breakWhile = true; uo0(W3Q *  
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for(int i=0;i<nStartPos.length;i++) *oF{ R^  
{ *m;L.r`5[  
if(!fileSplitterFetch.bDownOver) 8w\&QX  
{ ?h5Y^}8Qg  
breakWhile = false; #(7OvW+y  
break; yfU1;M
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} ?lTQjw{  
} E^rN)  
if(breakWhile) zw0p}  
break; %Z.!Bm:  
EV}%D9:  
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//count++; - na]P3 s  
//if(count>4) f~53:;L/  
// siteStop(); ALG +  
} }"szL=s  
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System.err.println("文件下载结束！"); u`ZnxD>  
} ]$7|1-&Y  
catch(Exception e){e.printStackTrace ();} Aam2Y,B  
} [P<oyd@#  
p4/
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//获得文件长度 u+-}|  
public long getFileSize() (h E^<jNR  
{ v"^G9u  
int nFileLength = -1; [[Z*n/tr  
try{ Z*k}I{0,-  
URL url = new URL(siteInfoBean.getSSiteURL()); J~~WV<6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >BiJ/[9  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5nk]{ G> V  
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int responseCode=httpConnection.getResponseCode(); RxAZ<8T_  
if(responseCode>=400) $:>K-4X\}  
{ ZN. #g_  
processErrorCode(responseCode); VlKWWQj  
return -2; //-2 represent access is error # TvY*D,  
} V ]Z{0  
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1Ztoj}!I  
String sHeader; l{kum2DT  
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for(int i=1;;i++) ;XANIT

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{ Qv#]T,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); zh7NXTzyf  
//Utility.log(in.readLine()); O}2;>eH  
sHeader=httpConnection.getHeaderFieldKey(i); `Os@/S  
if(sHeader!=null) -_B*~M/vV`  
{ 3d[fP#NY7  
if(sHeader.equals("Content-Length")) [V =O$X_  
{ K1jE_]@Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L,BuzU[1S  
break; GP1b/n3F1  
}
}DoNp[`  
} >Ka}v:E  
else u1rT:\G1  
break; y4+Km*am,W  
} $vx]\` ^  
} L~>pSP^a  
catch(IOException e){e.printStackTrace ();} d7A vx  
catch(Exception e){e.printStackTrace ();} jruwdm^  
N
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}
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Utility.log(nFileLength); [8[g_  
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return nFileLength; p4[cPt~C  
} F8KSB"!NR  
2{(_{9<>z  
lx(kbSxF  
//保存下载信息（文件指针位置） :hC+r=!I  
private void write_nPos() T:dV[3  
{ "|`euxYV  
try{ cJ=0zEv  
output = new DataOutputStream(new FileOutputStream(tmpFile)); x:4:G(  
output.writeInt(nStartPos.length); <A<N?`"  
for(int i=0;i<nStartPos.length;i++) /d*d'3{c  
{ G?*)0`~W  
// output.writeLong(nPos); E&9BeU a#  
output.writeLong(fileSplitterFetch.nStartPos); 8(]*J8/wt  
output.writeLong(fileSplitterFetch.nEndPos); q-}qrg  
} l]C#bL>i  
output.close(); ].w~FUa  
} g[4pG`z  
catch(IOException e){e.printStackTrace ();} Dn~c  
catch(Exception e){e.printStackTrace ();} l$ ^LY)i  
} b@`h]]~:  
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//读取保存的下载信息（文件指针位置） grrM[Y7#~b  
private void read_nPos()
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{ :Y>FuE  
try{ hh#p=Y(f  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9X/]O<i,Es  
int nCount = input.readInt(); Kjzo>fIC{  
nStartPos = new long[nCount]; n` M!K:Pq  
nEndPos = new long[nCount]; UB^OMB-W.m  
for(int i=0;i<nStartPos.length;i++) gjFpM.D-.  
{
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nStartPos = input.readLong(); y!eT>4Oyg  
nEndPos = input.readLong(); /0CS2mLC  
} *!NxtB!LC  
input.close(); gxPu/VD
4  
} 2fN2!OT  
catch(IOException e){e.printStackTrace ();} sBm)D=Kll  
catch(Exception e){e.printStackTrace ();} z*k(` '  
} +adwEYRrr  
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private void processErrorCode(int nErrorCode) y90wLU9f  
{ 4Dy|YH$>S  
System.err.println("Error Code : " + nErrorCode); *\gYs{,  
} +cWo^d.  
1 K(0tG:5  
sD#*W<  
//停止文件下载 717S3knlv  
public void siteStop() O#MaZ.=  
{ ^m Ua5w  
bStop = true; 6U9FvPJ  
for(int i=0;i<nStartPos.length;i++) ~)CGwST[  
fileSplitterFetch.splitterStop(); qf T71o(  
FRhHp(0}5  
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} 9x`1VR :  
} oZ5 ,y+L4  
//负责部分文件的抓取 0hg4y  
**FileSplitterFetch.java ;"B@QPX  
*/ L.2!Q3&  
package NetFox; ^|%
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import java.io.*; eHb@qKnf  
import java.net.*; twMDEw#VL  
[
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public class FileSplitterFetch extends Thread { YJGP8  
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[[#zB-|  
String sURL; //File URL m`BE{%  
long nStartPos; //File Snippet Start Position |BBo  
long nEndPos; //File Snippet End Position qr4.s$VGs*  
int nThreadID; //Thread's ID R0~w F>  
boolean bDownOver = false; //Downing is over K2
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boolean bStop = false; //Stop identical [2{2w68D!  
FileAccessI fileAccessI = null; //File Access interface x3:d/>b  
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i
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f|6 Y  
{ J\Db8O-/x4  
this.sURL = sURL; ^P|Zze zwU  
this.nStartPos = nStart; &G!~@\tMg  
this.nEndPos = nEnd; #(}'G*  
nThreadID = id; Dy&{PeE!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %6\L^RP  
} 4&AGVplgF  
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public void run() .B?fG)'WsF  
{ 1}R\L"  
while(nStartPos < nEndPos && !bStop) 
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{ C<#_1@^:8e  
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try{ QtA@p  
URL url = new URL(sURL); MxOIe|=&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &z05h<]  
httpConnection.setRequestProperty("User-Agent","NetFox"); N :OLN[  
String sProperty = "bytes="+nStartPos+"-"; 2?F?C  
httpConnection.setRequestProperty("RANGE",sProperty); Z.`0  
Utility.log(sProperty); 97dF  
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InputStream input = httpConnection.getInputStream(); P~84#5R1  
//logResponseHead(httpConnection); z))rk vL%  
;6$W-W _  
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byte[] b = new byte[1024]; WDI3*  
int nRead; _yp<#q]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~7gFddi=i  
{ X4L@|"ZI  
nStartPos += fileAccessI.write(b,0,nRead); JkI|Ojmm/  
//if(nThreadID == 1) hcpe~spz9|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~x[(1  
} GL _hRu  
0v#p4@Z  
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Utility.log("Thread " + nThreadID + " is over!"); !D!"ftOm  
bDownOver = true; mA#;6?6  
//nPos = fileAccessI.write (b,0,nRead); -Un"z6*  
} OepQ Z|2  
catch(Exception e){e.printStackTrace ();} 3L-$+j~u  
} 8_Z"@  
} /]?e^akA  
|9Y~
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,Iru_=Wk~  
//打印回应的头信息 3lbGG42:  
public void logResponseHead(HttpURLConnection con) !C(PfsrR/  
{ 7X8*7'.2  
for(int i=1;;i++) qT01@Bku  
{ ?4#  
String header=con.getHeaderFieldKey(i); :;;k+Sw3  
if(header!=null) gH.$B'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0EasPbp  
Utility.log(header+" : "+con.getHeaderField(header)); e0]#vqdO  
else +Ht(_+To1  
break; ~>Y^?l  
} pq%inSY  
} 36Lf8~d4"h  
;I6C`N  
#%pY,AK:=  
public void splitterStop() E2tUL#  
{ ]K+8f-  
bStop = true; 3v&Shb?xb;  
} oFhBq0@  
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} efuiFN;  
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wc#k@"2AZb  
/* r*ziO#[  
**FileAccess.java [ {HTGz@(  
*//文件访问(定位，写) >QPCYo<E  
package NetFox; nm)/BK  
import java.io.*; E&Zt<pRf;2  
=@&>r5W1  
4pZKm-dM^  
public class FileAccessI implements Serializable{ "Xl"H/3r  
rHqP[[4B'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 a@AIv"q  
RandomAccessFile oSavedFile; 3#aLCpVla  
long nPos; f%JM a]yV  
4hYK$!"r
 
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public FileAccessI() throws IOException cEn|
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{ #Zi6N  
this("",0); C>F5=&  
} LoOw]@>  
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public FileAccessI(String sName,long nPos) throws IOException oTr,zRL  
{ 06`caG|]-M  
oSavedFile = new RandomAccessFile(sName,"rw"); xZ* B}O{{H  
this.nPos = nPos; b2RW
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oSavedFile.seek(nPos); 9!0-~,o  
} s#aane  
x_
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~S<}q6H.  
public synchronized int write(byte[] b,int nStart,int nLen) _,? xc"  
{ 5g;mc.Cvt  
int n = -1; I0;gTpt9  
try{ zm_8{Rta}  
oSavedFile.write(b,nStart,nLen); N/1xc1$SB  
n = nLen; `uqe[u;`6  
} mnw(x#%
P  
catch(IOException e) X_)I"`  
{ uz:r'+v  
e.printStackTrace (); 
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} 9|NF)~Q}'  
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return n; oW>e.}d!  
} dnM.  
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} e@5w?QzW  
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#iRd2Qj%  
/* FTzc,6  
**SiteInfoBean.java i?V:+0#q\]  
*/ {IF$\{Al  
package NetFox; iQgr8[ SFf  
tVNFulcz$  
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public class SiteInfoBean { J<9}) m  
k9&W0$I#  
+
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private String sSiteURL; //Site's URL e?\hz\^  
private String sFilePath; //Saved File's Path !u/c
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private String sFileName; //Saved File's Name !,sQB_09C  
private int nSplitter; //Count of Splited Downloading File @Hr1.f  
VkId6k:>6C  
:3b\pEO9\  
public SiteInfoBean() %/}d'WJR  
{//nSplitter的缺省值为5 ~|oB|>  
//default value of nSplitter is 5 ;g?o~ev 8  
this("","","",5); x
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} 6I|9@~!y[  
f%P#.  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >
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{ $dK
o}  
sSiteURL= sURL; gEmsPk,  
sFilePath = sPath; gRw? <U^  
sFileName = sName; #wGOlW;R  
this.nSplitter = nSpiltter; [t*-s1cq  
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%  
}  [L  
{>Qs+]  
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public String getSSiteURL() cA{,2CYc  
{ @y|JIBBRc  
return sSiteURL; mhNgXp)_56  
} y#n
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<[17&F0  
public void setSSiteURL(String value) !3"Hn  
{ dAaxbP|  
sSiteURL = value; 8vj]S5  
} l5U^lc  
r90R~'5x9  
R?:(~ X\  
public String getSFilePath() Gd|j
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{ C`aUitL}  
return sFilePath; {y<E_y x1  
} zB6&),[,v  
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public void setSFilePath(String value) h|EHK!<"8  
{ !6J+#  
sFilePath = value; Enhrkk  
} pQ`S%]k.<  
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:|=Xh"l"  
public String getSFileName() CSr2\ogT  
{ OuB[[L  
return sFileName; 1+ V<-I@{  
} Oz=!EG|N  
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.Txwp?};  
public void setSFileName(String value) GJBMaT  
{ J^mm"2  
sFileName = value; tSiQrI  
} |(5|6r3  
3`ze<K((  
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public int getNSplitter() #o(@S{(NZ  
{ ^!K 8nW{*  
return nSplitter; V&d?4i4/Q  
} -M-y*P
)  
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public void setNSplitter(int nCount) deutY.7g  
{ T{Yk/Z/}?  
nSplitter = nCount; *35o$P4
6  
} wtfM}MW\  
} rmdG"s  
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;Y$d!an0  
/* )GJlQ1x  
**Utility.java z_:r&UP`"  
*/ $#
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package NetFox; !jN$U%/,%.  
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'V*8'?  
public class Utility { SqT+rvTh  
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public Utility() C] |m|`  
{ TK#-;p_  
&fifOF#[e  
[&{NgUgu"  
} Wu693<  
P)hawH=  
//线程睡眠 x_x|D|@wM  
public static void sleep(int nSecond) 9q"G g?  
{ h>"Z=y  
try{ cP8@'l@!  
Thread.sleep(nSecond); Ijs=4f  
} |r53>,oR<:  
catch(Exception e) S3YAc4  
{ avH3{V  
e.printStackTrace (); M,N(be-  
} b]\V~ZaXG  
} R]_fe4Y0  
{>.qo<k  
//日志 XOJ@-^BX  
public static void log(String sMsg) L&~>(/*7U  
{ l,1.6  
System.err.println(sMsg); iTeFy-Ct  
} DT#Z6A  
Mer\W6e"e  
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public static void log(int sMsg) /4u:5G  
{ 8\8%FSrc  
System.err.println(sMsg); w7h=vy n?  
} AmT*{Fz8  
} I,!>ZG@6  
Z!qF0UDj  
\fD[Ej  
/* 1V1T1  
**TestMethod.java 74*iF'f?c  
*/ ^->vUf7PX  
package NetFox; ^b(>Bg)T  
}@wXm  
IctLhYZ  
public class TestMethod { ]lzOz<0q  

Z(fhH..T`  
8^dsx1U#  
public TestMethod() z50f$!?  
{ ///xx/weblogic60b2_win.exe Q*AgFF%wn  
try{ T 9?!.o  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); VEg/x z4c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); w'Q2Czso  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7
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fileFetch.start(); J*O$)K%Hx  
} Bn{0-5nj  
catch(Exception e){e.printStackTrace ();} "Q<*H<e  
;^:$O6J7T~  
&:)e  
} JSm3ZP|GqJ  
k~b8=$  
f7QX"p&P  
public static void main(String[] args) f^X\N/  
{ pGGx.&5#82  
new TestMethod(); hKW!kA=gZ  
} {:9P4<%H  
} z?8Sie  
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