http断点续传简单实现（java)

/* 0N[&3Ee8  
**SiteFileFetch.java mpAR7AG6  
*/ F|Mi{5G%  
package NetFox; ZUz ^!d  
import java.io.*; Re:jVJgBz  
import java.net.*; 6:GTD$Uz.  
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public class SiteFileFetch extends Thread { >_rha~   
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SiteInfoBean siteInfoBean = null; //文件信息Bean V@>r*7\F  
long[] nStartPos; //开始位置 GRb*EeT  
long[] nEndPos; //结束位置 T2}FYVj?!g  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S6}@I ,Q  
long nFileLength; //文件长度 ,fK3ZC  
boolean bFirst = true; //是否第一次取文件 "|;:>{JC  
boolean bStop = false; //停止标志 V/cP4{L  
File tmpFile; //文件下载的临时信息 bCref$|  
DataOutputStream output; //输出到文件的输出流 Y2xL>F  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Um1[sMc{au  
public SiteFileFetch(SiteInfoBean bean) throws IOException Z3>N<u8)  
{ X37L\e[c  
siteInfoBean = bean; ,yd MU\so(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); q@b|F-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \V9Z#>  
if(tmpFile.exists ()) -.g|l\  
{ NCxqh<  
bFirst = false; RoCfJ65  
read_nPos(); 0|R#Tb;Y  
} ;a-$D]Db  
else +/#Ei'do  
{ >=]'hyn]]  
nStartPos = new long[bean.getNSplitter()]; C6O8RHg  
nEndPos = new long[bean.getNSplitter()]; ??n*2s@t  
} /Q,{?';~  
}2K$^uR  
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} &1+X\c+tb  
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public void run() U4 13?
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{ D:Q 21Ch  
//获得文件长度 Ib
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//分割文件 >^Se'SE]  
//实例FileSplitterFetch Hm+ODv9  
//启动FileSplitterFetch线程 D")_;NLE1  
//等待子线程返回 Lh.`C7]
  
try{ sp@E8G%xO  
if(bFirst) P2nft2/eu?  
{ 2e$w?W0^  
nFileLength = getFileSize(); &$`yo`  
if(nFileLength == -1) DGevE~  
{ ,f1q)Qf  
System.err.println("File Length is not known!"); jy]JiQB  
} `DT3x{}_S  
else if(nFileLength == -2) 8k(P,o  
{ upeU52@\  
System.err.println("File is not access!"); R
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} >J|]moSVA  
else a_h]?5 :c  
{ >vuY+o;B  
for(int i=0;i<nStartPos.length;i++) e" ]2=5g  
{ 7\ nf:.  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
9CCkqB/  
} )5|I_PXB  
for(int i=0;i<nEndPos.length-1;i++) q~o,WZG  
{ +za8=`2o  
nEndPos = nStartPos[i+1]; XQ4G)  
} S1/`th  
nEndPos[nEndPos.length-1] = nFileLength; K\vSB~{[  
} ['%69dPh  
} RT>{*E<I  
U%h);!<  
%lg=YGLQB  
//启动子线程 ;Ag 3c+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; WD'#5]#Y  
for(int i=0;i<nStartPos.length;i++) ' oFxR003  
{ 8ssJ<
LP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c\% r3
8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), tK k#LWB  
nStartPos,nEndPos,i); ?BhMjsy.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P>9aI/d9  
fileSplitterFetch.start(); 8u!
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} D1nq2GwS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V'w@rc\XN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w&xDOyW]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O$IjNx  
nEndPos = " + nFileLength); m^x6>9,  
// fileSplitterFetch[nPos.length-1].start(); au,t%8AC  
^<X@s1^#  
t<n"-Tqu  
//等待子线程结束 .(Qx{r$  
//int count = 0; Tr^nkD{  
//是否结束while循环 k1VT /u  
boolean breakWhile = false; V^Hu3aUx8  
~q&pF"va8  
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while(!bStop) ]0L&v7[  
{ nk3y"ne7  
write_nPos(); *Sh^J+j  
Utility.sleep(500); xG;-bJu  
breakWhile = true; D/h/Y) Y  
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for(int i=0;i<nStartPos.length;i++) 4[r/}/iGo  
{ fr!Pj(Q1  
if(!fileSplitterFetch.bDownOver) Py{<bd  
{ (MHAJ]Rx  
breakWhile = false; d6i6hcQE  
break; f{0F|w<gf  
} GUQ{r!S  
} 4Z|vnj)Z  
if(breakWhile) ~
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break; JF/,K"J  
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W5#611  
//count++; I7^zU3]Ul  
//if(count>4) pu,?<@0YK  
// siteStop(); 0EJ(.8hwm  
} 7)%+=@  
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US  
System.err.println("文件下载结束！"); hQNe;R5  
} ;l}- Z@! /  
catch(Exception e){e.printStackTrace ();} 1n\ t+F  
} _e9:me5d"$  
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//获得文件长度 (LHp%LaZ\;  
public long getFileSize() e$Y[Z{T5  
{ GA`PY-Vs)  
int nFileLength = -1; e*j.  
try{ ZtHm\VTS  
URL url = new URL(siteInfoBean.getSSiteURL()); lD{Aa!\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?uMQP NYs  
httpConnection.setRequestProperty("User-Agent","NetFox"); {D g_?._d  
HHjt/gc}`  
l
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int responseCode=httpConnection.getResponseCode(); s}onsC  
if(responseCode>=400) `<[6YH_  
{ z6py"J@  
processErrorCode(responseCode); /.M+fr S  
return -2; //-2 represent access is error <W]g2>9o9  
} ];%0qb  
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String sHeader; n4lutnF  
|j3'eW&=  
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for(int i=1;;i++) !`bio cA  
{ ,7XtH>2s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SR*wvQnOx  
//Utility.log(in.readLine()); ?|e'Gbb_  
sHeader=httpConnection.getHeaderFieldKey(i); (Z5##dS3  
if(sHeader!=null) @E.k/G!~Nb  
{ ) _ I,KEe  
if(sHeader.equals("Content-Length")) #.[AK_S5&  
{ 8.bKb<y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m
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break; P,=+W(s9}  
} q.2(OP>(  
} kF7V.m/~o  
else bxK(9.  
break; E+C5 h ;p&  
} i@NqC;~;  
} 4 g. bR  
catch(IOException e){e.printStackTrace ();} 1009ES7*  
catch(Exception e){e.printStackTrace ();} a(]`F(L  
L !4t[hhe=  
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Utility.log(nFileLength); $;G{Pyp  
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return nFileLength; f
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} F_uY{bg  
3?E8\^N\n  
lt$zA%`odc  
//保存下载信息（文件指针位置） . |*f!
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private void write_nPos() H UoyLy  
{ !6&W,0<  
try{ `MP|Ovns:H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +jC*'7p@  
output.writeInt(nStartPos.length); sS TPMh  
for(int i=0;i<nStartPos.length;i++)  htY=w}>  
{ -yDs< Xl  
// output.writeLong(nPos); .k4W_9  
output.writeLong(fileSplitterFetch.nStartPos); `bKA+c,f  
output.writeLong(fileSplitterFetch.nEndPos); D\/xu-&  
} _ .i3,-l)  
output.close(); >\ST-7
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} VGL#!4wK  
catch(IOException e){e.printStackTrace ();} ~"Gf<3^y+  
catch(Exception e){e.printStackTrace ();} ]\RRqLDzkg  
} FZiW|G  
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//读取保存的下载信息（文件指针位置） VCy5JH  
private void read_nPos() I &*_,d  
{ gfU-"VpHE  
try{ &/.hx(#d  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); VE2tq k%  
int nCount = input.readInt(); +MK6zf  
nStartPos = new long[nCount]; c^8o~K>w84  
nEndPos = new long[nCount]; TST4Vy3  
for(int i=0;i<nStartPos.length;i++) >Q,zNs  
{ ECa$vvK m  
nStartPos = input.readLong(); 9s +z B  
nEndPos = input.readLong(); hgRVwX  
} nxQ?bk}*d  
input.close(); vFrt|JC_{  
} mYB`)M*Y  
catch(IOException e){e.printStackTrace ();} :"0J=>PH:  
catch(Exception e){e.printStackTrace ();} b{DiM098  
} UkCnqNvx  
/\mKY%kyh  
/RLq>#:h**  
private void processErrorCode(int nErrorCode) `nR%Cav,U  
{ CBf7]n0H  
System.err.println("Error Code : " + nErrorCode); CLKov\U\  
} #$vRJ#S}U  
&@"]+33  
hM@\RPsY  
//停止文件下载 G)>W'yxQ  
public void siteStop() 2Ha5yaTL  
{ +)nT|w45  
bStop = true; iV.p5F
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for(int i=0;i<nStartPos.length;i++) ~`Qko-a&  
fileSplitterFetch.splitterStop(); M^rM-{?<  
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} Y^"4?96  
} m8+(%>+
7  
//负责部分文件的抓取 l^NC]t  
**FileSplitterFetch.java D}Ilyk_uUw  
*/ F="z]C;u  
package NetFox; ~#:e*:ro  
lhC6S'vq  
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import java.io.*; ~c{:DM  
import java.net.*; cd;NpN  
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public class FileSplitterFetch extends Thread { u"$a>S_  
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String sURL; //File URL T#:F]=  
long nStartPos; //File Snippet Start Position vd#,DU=p!  
long nEndPos; //File Snippet End Position LU!1s@  
int nThreadID; //Thread's ID -'rj&x{Q)U  
boolean bDownOver = false; //Downing is over iZ[tHw||  
boolean bStop = false; //Stop identical Q"a2.9
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FileAccessI fileAccessI = null; //File Access interface Z#`0txCF  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c)C5KaiPG  
{ IN^9uL]B  
this.sURL = sURL; ST1Ts5I  
this.nStartPos = nStart;  *2u E  
this.nEndPos = nEnd; fUag1d  
nThreadID = id; rlok%Rt4Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 QF-)^`N  
} .BTx&AqU  
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public void run() !^U6Z@&/R  
{ {j(4m  
while(nStartPos < nEndPos && !bStop) >3;^l/2c  
{ ](r ^.
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try{ 5!fSW2N  
URL url = new URL(sURL); ^6/j_G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "2n;3ByR  
httpConnection.setRequestProperty("User-Agent","NetFox"); DM7}&~  
String sProperty = "bytes="+nStartPos+"-"; 3 %(Y$8U  
httpConnection.setRequestProperty("RANGE",sProperty); _^uc 0=  
Utility.log(sProperty); >.dHt\  
7{BnXN[  
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InputStream input = httpConnection.getInputStream(); $fArk36O#  
//logResponseHead(httpConnection); ":WYcaSi  
*d*oS7  
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byte[] b = new byte[1024]; l[n@/%2  
int nRead; ^JhFI*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) e&J3N  
{ QJ4AL3 ^6
 
nStartPos += fileAccessI.write(b,0,nRead); HY;oy(  
//if(nThreadID == 1) :k!j"@r  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i^%-aBZ  
} < tQc_  
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Utility.log("Thread " + nThreadID + " is over!"); IlHY%8F{  
bDownOver = true; n!.2aq  
//nPos = fileAccessI.write (b,0,nRead); t!l%/$-  
} :4;S"p  
catch(Exception e){e.printStackTrace ();} u7k|7e=xk  
} Jirct,k  
} 4]6Qr  
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//打印回应的头信息 ^tE_LL+ji|  
public void logResponseHead(HttpURLConnection con) ZH-5Qy_  
{ *caLN,G  
for(int i=1;;i++) 5-p.MGso  
{ CX+9R3pa  
String header=con.getHeaderFieldKey(i); g3rRhS  
if(header!=null) 7z<Cu<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); QFzFL-H~N  
Utility.log(header+" : "+con.getHeaderField(header)); Yn1?#%%  
else VN|G5*  
break; Pf8u/?/  
} jfSg){  
} 1pCkWe  
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V<-htV  
public void splitterStop() *-z4<LAa  
{ 94z8B;+H]  
bStop = true; qz:]-A  
} A7'bNd6f9  
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} i`~~+6`J  
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6$z'wy/*  
/* X8b#[40:  
**FileAccess.java {bTeAfbf]  
*//文件访问(定位，写) n#>5?W  
package NetFox; `cO|RhD@  
import java.io.*; no3Z\@%  
cj^bh  
R9=K(pOT  
public class FileAccessI implements Serializable{ e`ex]py<C  
!w=,p.?V=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P!>g7X  
RandomAccessFile oSavedFile; 3uO8v{`  
long nPos; [0op)Kn  
a 2Et,WA%  
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public FileAccessI() throws IOException Gt'/D>FE0  
{ U9F6d!:L7A  
this("",0); qL>v&Rd<  
} 'fl(N2t  
RO$*G jQd  
]+lF=kkc%  
public FileAccessI(String sName,long nPos) throws IOException paYz[Xq  
{ ^?sSx!:bZ  
oSavedFile = new RandomAccessFile(sName,"rw"); V g6S/-  
this.nPos = nPos; ]Da4.s*mW  
oSavedFile.seek(nPos); +U=KXv  
} u7u~  
p|s2G~0<  
LT&/0  
public synchronized int write(byte[] b,int nStart,int nLen) JilKZQmk  
{ R25-/6_V>  
int n = -1; Xr2 Wa  
try{ U2=hSzY  
oSavedFile.write(b,nStart,nLen); ax]9QrA  
n = nLen; K /ZHJkJ7  
} } Ab_o#Zy  
catch(IOException e) /gX%ABmS  
{ ebD{ pc`&  
e.printStackTrace (); %\l0-RA@<  
} &&*wmnWCS{  
[[$Mh_MD  
dL(4
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return n; D0KELAcY  
} ]eD[4Y\#t  
}M="oN~w  
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} d>~`j8,B  
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v<`$bvv?  
/* Pd
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**SiteInfoBean.java $4:~*IQ  
*/
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package NetFox; ]Qc: Zy3  
X)y*#U  
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public class SiteInfoBean { G*=H;Upi  
4(;20(q]  
8m \;P  
private String sSiteURL; //Site's URL #-A5Z;TD.  
private String sFilePath; //Saved File's Path E8 \\X  
private String sFileName; //Saved File's Name wb@]>MJ}[s  
private int nSplitter; //Count of Splited Downloading File 6XZN>#  
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z*  
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public SiteInfoBean() r*>QT:sB  
{//nSplitter的缺省值为5 iAg}pwU  
//default value of nSplitter is 5 NrW[Q3E$  
this("","","",5); JfR kp  
} VJGwd`qo*A  
mxZ4 HD{
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &4[<F"W>47  
{ `c>A
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sSiteURL= sURL; :> x:(K  
sFilePath = sPath; EyzY2>"^  
sFileName = sName; }
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this.nSplitter = nSpiltter; T<_+3kw  
&KLvr|  
;,R[]B01u  
} E=3#TBd  
:E}6S  
"hz>{oe  
public String getSSiteURL() i^~sn `o  
{ 5NFq7&rJ6  
return sSiteURL; e-1;dX HL  
} n2H&t>N  
#dL5x{gV=  
uTxX`vH@!  
public void setSSiteURL(String value) |:{g?4Mi  
{ hLCsQYNDU  
sSiteURL = value; 9$8X>T^  
} $]xE$dzJ  
]U#JsMS  
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public String getSFilePath() L)@`58Eil  
{ iz,]%<_PE  
return sFilePath; l A 0-?k  
} ^V_ku@DY  
|)~Ex 9%ev  
wbn^R'  
public void setSFilePath(String value) ?]759,Q3L  
{ ;B,nzx(L  
sFilePath = value; 6oPUYn-  
}
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8Ix-i  
$b&BH'*'~  
public String getSFileName() ,M| QN*  
{ PEK.Kt\M  
return sFileName; B!$V
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} cu)@P0I  
[%HYh7ua<  
I3V{"Nx6  
public void setSFileName(String value) c8H9_6  
{ 2(@LRl>:  
sFileName = value; [P(rY  
} 9(i0"hS^  
&Xj{:s#  
5)h+(u C3  
public int getNSplitter() W9:fKP  
{ uZo]8mV  
return nSplitter; i7Y s_8A"9  
} BXagSenc  
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o6`Y7,]  
public void setNSplitter(int nCount) GGYX!=]~  
{ r3*+8D~a_  
nSplitter = nCount; $w 5#2Za  
} s|fCR  
} jAD+:@  
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,<R>Hiwg/s  
/* WRN8#b  
**Utility.java WsG"x>1n  
*/ Fr938q6^-  
package NetFox; Uqb
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u&hDjE  
9Ba%=  
public class Utility { JNU"5sB  
[,.[gWA  
a>-}\GXTA  
public Utility() n23%[#,r  
{
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3:l:~Vn  
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} xMO[3D&D  
g] 7{5  
//线程睡眠 /y+;g{  
public static void sleep(int nSecond) lq78gOg{  
{ Fjb4BdZP  
try{ IN]`lJ  
Thread.sleep(nSecond); A&X  
} %OezaNOtm  
catch(Exception e) duZ|mT8Q==  
{ y\r^\ S9%  
e.printStackTrace (); wR5\^[GN  
} .b!OZ  
} j\i;'t}8g  
ox i a}  
//日志 gNMKGf\Y  
public static void log(String sMsg) ^?sSsHz  
{ VuJfo9 `E  
System.err.println(sMsg); MbT ONt?~v  
} [="g|/M)  
W07-JHV%  
AaCnTRG  
public static void log(int sMsg) 8gu'dG=  
{ 02]8|B(E90  
System.err.println(sMsg); Fyi?,,  
} y{&{=1#  
} |,M#8NOp:  
iZDb.9@&t  
!>a&`j2:W  
/*  8o%<.]   
**TestMethod.java 42b=z//;  
*/ t?Njw7  
package NetFox; *Dd(+NI  
y4)ZUv,}  
HlOAo:8'  
public class TestMethod { k=ior  
X$j|/))  
~x+:44*  
public TestMethod() eE#81]'6a  
{ ///xx/weblogic60b2_win.exe cAsSN.HFS  
try{ S+Yy  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &kr_CP:;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); uJ)\P  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^>vO5Ho.  
fileFetch.start(); h^[ppc{Z  
} $h|I7`  
catch(Exception e){e.printStackTrace ();} 9:}RlL+cOk  
F| ,Vw{  
;ZE<6;#3IP  
} ^G7n#  
RpaA)R,  
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public static void main(String[] args) )+Y\NO?O  
{ 6a2w-}Fs  
new TestMethod(); SoM ]2^  
} SzgY2+Qq  
} rH}Dt@  
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