http断点续传简单实现（java)

/* xOT'4v&.  
**SiteFileFetch.java Ynz^M{9)K  
*/ gn%#2:=pVu  
package NetFox; (dMFYL>YP  
import java.io.*; -(c
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import java.net.*; #]lUJ &M}e  
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public class SiteFileFetch extends Thread { oTI*mGR1Z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Ro<!n>
H  
long[] nStartPos; //开始位置 zr[~wM  
long[] nEndPos; //结束位置 19N:9;Ixz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xJ"Zg]d{  
long nFileLength; //文件长度 /ruf1?\,R  
boolean bFirst = true; //是否第一次取文件 6~!YEuA  
boolean bStop = false; //停止标志 4X\*kF%  
File tmpFile; //文件下载的临时信息 
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DataOutputStream output; //输出到文件的输出流 JxLH]1b  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） D{
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public SiteFileFetch(SiteInfoBean bean) throws IOException f%|S>(   
{ }oN(nPxv9  
siteInfoBean = bean; T^nX+;:|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); I2W2B3D` c  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Vks,3$  
if(tmpFile.exists ()) NDg]s2T  
{ J<BdIKCma  
bFirst = false; [e}]K:  
read_nPos(); ky~x4_y5  
} &(rd{j/*  
else }w-`J5Eq#  
{ >bZ#  
nStartPos = new long[bean.getNSplitter()]; qXhrK /  
nEndPos = new long[bean.getNSplitter()]; OK)0no=OAK  
} X,fTzkGj  
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} <+$S{Z.  
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public void run() .lFSFJ??  
{ IRU2/Ycg  
//获得文件长度 R/wSGP`W  
//分割文件 s{,e^T  
//实例FileSplitterFetch /,>.${,;u  
//启动FileSplitterFetch线程 }O>Zu[8a  
//等待子线程返回 z8!u6odu %  
try{ _@p|A  
if(bFirst) '" tieew  
{ d+;wDu  
nFileLength = getFileSize(); {+[gf:Ev  
if(nFileLength == -1)  qN QsU  
{ [T%blaSX  
System.err.println("File Length is not known!"); :mrGB3x{  
} kwL)&@  
else if(nFileLength == -2) Ih7Eq/iu  
{
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System.err.println("File is not access!"); o{he)r6)_  
} VM,ZEt3Vy  
else Za6oYM_z  
{ uqUo4z5T  
for(int i=0;i<nStartPos.length;i++) Z:v1?v  
{ ,$]q2aL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N93E;B  
} _tk5?9Ykn  
for(int i=0;i<nEndPos.length-1;i++) vck$@3*  
{ ) G{v>Z,  
nEndPos = nStartPos[i+1]; 3XnXQ/({  
} $"8k|^Z3  
nEndPos[nEndPos.length-1] = nFileLength; w!}1oy  
} 6a?y$+pr  
} vVW=1(QWI#  
o.5j@dr  
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//启动子线程 /wTf&_"mTL  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [86'/:L\2  
for(int i=0;i<nStartPos.length;i++) ;SW-dfo2i  
{ ptR  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;Kf|a}m-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %RN-J*s]  
nStartPos,nEndPos,i); ay_D.gxz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hNle;&*F  
fileSplitterFetch.start(); JB+pFBeY  
} 9NP l]iA)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MuobMD}jqe  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); R`Lm"5w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p*0Ve21i,  
nEndPos = " + nFileLength); #CPPdU$  
// fileSplitterFetch[nPos.length-1].start(); ;}~=W!yz  
$5b|@  
#%9]Lq  
//等待子线程结束 '-IT@}  
//int count = 0; r?!xL\C\  
//是否结束while循环 J,O@T)S@  
boolean breakWhile = false; j/<y  
 J31M:<  
tA-B3 ]  
while(!bStop) #Qr4Ke$g[l  
{ JP4Moq~r   
write_nPos(); XijLS7Aw|  
Utility.sleep(500); V]]qu:Mh8  
breakWhile = true; |T_Pz&-  
@vYmkF`  
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for(int i=0;i<nStartPos.length;i++) O->eg  
{ fmJWd|  
if(!fileSplitterFetch.bDownOver) 2&0<$>  
{ *Zi%Q[0Me  
breakWhile = false; p'uz2
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break; $ rYS  
} &=Zg0Q  
} />Vx*^u8Hz  
if(breakWhile) }4]<P  
break; ZZU8B?)  
#( sNk,^Ax  
=&pN8PEn\  
//count++; &fW=5'  
//if(count>4) yCIgxPv|7  
// siteStop(); <j\;>3Q  
} .4<U*Xkt  
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System.err.println("文件下载结束！"); \( <{)GpBi  
} WcwW@cY7\  
catch(Exception e){e.printStackTrace ();} y8vH?^:%<  
} P\4tK<P|  
+n[wkgFd  
I#X2UQzP  
//获得文件长度 U%DF!~n  
public long getFileSize() Bh,)5E^m  
{ kc'0NE4oq  
int nFileLength = -1; %Z[/U  
try{ 1MI7l)D?  
URL url = new URL(siteInfoBean.getSSiteURL()); I'9s=~VfY,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +M##mRD  
httpConnection.setRequestProperty("User-Agent","NetFox"); [4Faq3T"  
^D;D8A.  
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int responseCode=httpConnection.getResponseCode(); h ^h-pd  
if(responseCode>=400) GR ?u?-  
{ U|7Qw|I7  
processErrorCode(responseCode); |3:=qpT-  
return -2; //-2 represent access is error >&vO4L  
} /=m9s  
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String sHeader; -;)SER3Wq4  
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for(int i=1;;i++) wUCDJY:,1  
{ :"P hkR  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]KK ZbEO  
//Utility.log(in.readLine()); G0QXf  
sHeader=httpConnection.getHeaderFieldKey(i); DIqT>HHZ  
if(sHeader!=null) pOVghllO  
{ zrU$SWU  
if(sHeader.equals("Content-Length")) tOM3Gs~o6z  
{ 4@]xn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #* gU[9U~  
break; _'hCUXeY'  
} KTK6#[8A  
} |5IY`;+9  
else @`;Y/',  
break; Pkx(M E  
} {,f!'i&b@  
} :.S41S   
catch(IOException e){e.printStackTrace ();} \+Rwm:lI  
catch(Exception e){e.printStackTrace ();} qi SEnRG.  
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Utility.log(nFileLength); ^s@*ISY  
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return nFileLength; 5Vqmv<F;$Z  
} *[xNp[
4EU  
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//保存下载信息（文件指针位置） (: TGev  
private void write_nPos() UiK+c30FU  
{ *lerPY3 q  
try{ ^[seK)S=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^Em@6fz[  
output.writeInt(nStartPos.length); P\X=*  
for(int i=0;i<nStartPos.length;i++) ~6:LUM  
{ {{]=zt|69  
// output.writeLong(nPos); /y](mu"!  
output.writeLong(fileSplitterFetch.nStartPos); 6PJJ?}P^1  
output.writeLong(fileSplitterFetch.nEndPos); "_1-IE  
} )qyx|D  
output.close(); ~f=6?5.wa  
} dx13vZ3[U  
catch(IOException e){e.printStackTrace ();} XW~ BEa  
catch(Exception e){e.printStackTrace ();} tT* W5  
} YZBzv2'\x  
qsft*&  
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//读取保存的下载信息（文件指针位置） I^M#[xA  
private void read_nPos()  bL'#  
{ :nKsZ1bX  
try{ d
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5S\][;u  
int nCount = input.readInt(); wI@zPVY_i  
nStartPos = new long[nCount]; w(V?N'[  
nEndPos = new long[nCount]; Ql q#Zdru  
for(int i=0;i<nStartPos.length;i++) 2%5^Fi  
{ ?79SPp)oo  
nStartPos = input.readLong(); !qTpQ5Dm  
nEndPos = input.readLong(); n~,]KdU]  
} 8sR  
input.close(); UU.mdSL  
}  \Z\IK  
catch(IOException e){e.printStackTrace ();} qP;{3FSkAF  
catch(Exception e){e.printStackTrace ();} ~Q_)>|R2  
} Pe$^Mo.q  
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private void processErrorCode(int nErrorCode) =M1a0i|d  
{ zj9bSDVL(  
System.err.println("Error Code : " + nErrorCode); I3G*+6V  
} ~jp!"f  
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//停止文件下载 iJ`%yg,  
public void siteStop()
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{ #JL&]Z+X6  
bStop = true; _'!N q  
for(int i=0;i<nStartPos.length;i++) L876$  
fileSplitterFetch.splitterStop(); $ ]W[y=  
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} YW?7*go'Z  
} {k_ PMl0G  
//负责部分文件的抓取 o%V @D'w  
**FileSplitterFetch.java [!J @a  
*/ Q? <-`7  
package NetFox;
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import java.io.*; J ?ztn  
import java.net.*; }t@f|TX  
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public class FileSplitterFetch extends Thread { L _vblUDq  
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String sURL; //File URL BKE\SWu  
long nStartPos; //File Snippet Start Position ~rgf{oGz  
long nEndPos; //File Snippet End Position WZ^
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int nThreadID; //Thread's ID Y|%anTP  
boolean bDownOver = false; //Downing is over $i,6B9  
boolean bStop = false; //Stop identical DO7-=74=  
FileAccessI fileAccessI = null; //File Access interface /*u#Ba<<  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException b4Ricm  
{ 6WA|'|}=  
this.sURL = sURL; 1
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this.nStartPos = nStart; t{/:(Nu  
this.nEndPos = nEnd; p!HPp Ef+#  
nThreadID = id; "XGD:>Q.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 vnz[w=U  
} TpJg-F  
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public void run() =dgo!k  
{ Q^$ghZ6V  
while(nStartPos < nEndPos && !bStop) ZhhI@_sz  
{ zW%>"y  
7))y}N:p
 
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try{ FX%t  
URL url = new URL(sURL); ^~ Ekg:`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gW%pM{PW  
httpConnection.setRequestProperty("User-Agent","NetFox"); ! 9d_Gf-  
String sProperty = "bytes="+nStartPos+"-"; #d7N| 9_  
httpConnection.setRequestProperty("RANGE",sProperty); !OPSSP]-  
Utility.log(sProperty); ,9=gVW{  
>%9^%p^  
J?._/RL8-  
InputStream input = httpConnection.getInputStream(); lbQ6 a  
//logResponseHead(httpConnection); AI&qU/}  
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byte[] b = new byte[1024]; 8 ne/=N|,  
int nRead; 1S+;ZMk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~c9>Nr9|`  
{ f"vk# 3  
nStartPos += fileAccessI.write(b,0,nRead); v2Dt3$@H6  
//if(nThreadID == 1) uzHT.
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YSqv86  
} *,"jF!C&[  
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Utility.log("Thread " + nThreadID + " is over!"); j'3j}G%\T  
bDownOver = true; ec`bz "1  
//nPos = fileAccessI.write (b,0,nRead); ,%A)"doaG  
} bRWIDPh  
catch(Exception e){e.printStackTrace ();} 8V6=i'GK  
} *%:@ cbF-M  
} &svx@wW  
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//打印回应的头信息 `-4'/~G  
public void logResponseHead(HttpURLConnection con) LyGUvi  
{ yC W*fIaq  
for(int i=1;;i++) IT
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{ }x]&L/  
String header=con.getHeaderFieldKey(i);  ( :  
if(header!=null) A'GlCp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5gSylts8  
Utility.log(header+" : "+con.getHeaderField(header)); 34z_+  
else 5QAdcEcN@O  
break; 0Y7$d`  
} B1E$v(P3M  
} '0Lov]L  
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public void splitterStop() E(_KN[}S  
{ K]X`sH:  
bStop = true; yk<VlS  
} ^pj>9%  
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} bMsECA&  
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/* [q1Unm  
**FileAccess.java }g>kpa0c  
*//文件访问(定位，写) Y=E9zUF  
package NetFox; Rv,82iEKs  
import java.io.*; qYK4)JP  
@M=$qO_$9  

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public class FileAccessI implements Serializable{ s D_G)c  
b4C
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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 RAV^D.  
RandomAccessFile oSavedFile; L x.jrF|&  
long nPos; cJ. 7Mt  
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public FileAccessI() throws IOException %%&e"&7HE  
{ z$|;-u|  
this("",0); B52yaG8C  
} 4@6<  
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public FileAccessI(String sName,long nPos) throws IOException /YFa ;2 W  
{ ZYa\"zp-  
oSavedFile = new RandomAccessFile(sName,"rw"); G=|70pxU  
this.nPos = nPos; :k~dj C  
oSavedFile.seek(nPos); :=9<  
} 9*\g`fWc}{  

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public synchronized int write(byte[] b,int nStart,int nLen) n3$gx,KL  
{ GF'f[F6oI  
int n = -1; Q.A \U>AgV  
try{ 0 _A23.Y  
oSavedFile.write(b,nStart,nLen); hU"F;4p  
n = nLen; o\4CoeG  
} )t%h[0{{  
catch(IOException e) RDJ+QOVKg  
{ oxfF`L"  
e.printStackTrace ();  <B)   
} :3^dF}>  
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return n; hm\\'_u  
} u]E.iXp  
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} I8u!\F  
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/* _R^y\1Qu  
**SiteInfoBean.java ARF\fF|<2  
*/ 1k[GuG%/K  
package NetFox; 6{=_718l`  
>b48>@~b
Y  
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public class SiteInfoBean { 514Z<omrK  
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private String sSiteURL; //Site's URL g1{/ 5{XI  
private String sFilePath; //Saved File's Path ?#BV+#(  
private String sFileName; //Saved File's Name \|%E%Yc
 
private int nSplitter; //Count of Splited Downloading File u,o1{%O  
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*5D3vB*S  
public SiteInfoBean() xE1'&!4O  
{//nSplitter的缺省值为5 n@ [  
//default value of nSplitter is 5 !D:Jbt@R<n  
this("","","",5); S!hXf|*0[  
} zkexei4^<  
.'T40=7  
{kL&Rv%'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3-|3`(  
{ =6\LIbO  
sSiteURL= sURL; !^WHZv4  
sFilePath = sPath; S^N{wZo  
sFileName = sName; :(,mL2[  
this.nSplitter = nSpiltter; fu4!t31  
0V`[Zgf  
#jA)>z\Q^  
} 1e}8LH7  
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public String getSSiteURL() O/b+CSS1  
{ C:i|-te  
return sSiteURL; 7-*=|gl+  
} V%NeZ1{ e  
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public void setSSiteURL(String value) aG{$I
c  
{ vzXag*0  
sSiteURL = value; YGk9b+`  
} %8r/oS  
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.L EY=j!-s  
public String getSFilePath() 6F|j(LB  
{ ~OypE4./1  
return sFilePath; h<x4YB5Mj  
} wCCV2tk  
u0 y 1  
P^)q=A8Z#  
public void setSFilePath(String value) jc:s` 4  
{ \/5RL@X}  
sFilePath = value; |+}G|hx@9  
} lzhqcL"  
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wtH~-xSB|  
public String getSFileName() XP
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{ p|[B =.c{  
return sFileName; fex,z%}p  
} -VT+O+9_A  
ig+4S[L~n  
[[+ pMI  
public void setSFileName(String value) +TJEG?o  
{ ~*.-  
sFileName = value; '@=PGpRF  
} T!|=El>  
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ST dNM\+  
public int getNSplitter() Z(GfK0vU
 
{ W|5_$p  
return nSplitter; Um.qRZ?  
} ae+*=,  
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public void setNSplitter(int nCount) bC6oqF'#  
{ 9`B$V##-L  
nSplitter = nCount; y2|R.EU\m<  
} p $`92Be/  
} *>[3I}mM  
]! *[Q\  
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/* K8I$]M  
**Utility.java 6'-As=iw  
*/ +.yT/y"  
package NetFox; =E*Gb[r_7  
Y.6SOu5$]  
u bW]-U=T  
public class Utility { 1;F`c`0
<  
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public Utility() 7'lZg<z{~j  
{ 2kh"8oQ  
m#7*:i&@Y  
}6u2*(TmD  
} 8|^CK|m6*  
{*m?Kc7k  
//线程睡眠 SPkn3D6  
public static void sleep(int nSecond) 5*-3? <)e  
{ 7^6uG6  
try{ K9Hqq7"%  
Thread.sleep(nSecond); }^kL|qmjR  
} yd_ (?V&;_  
catch(Exception e) vX|UgK?2^  
{ 5Wx~ZQZ  
e.printStackTrace (); Wr?'$:  
} 7:E!b=o#  
} K%5"u'  
e^1uVN  
//日志 yV_wDeAz  
public static void log(String sMsg) A!i q->+  
{ kFLB> j97  
System.err.println(sMsg); GX{XdJD  
} zg)sd1@  
x2Lq=zwJ  
&HZmQ>!R D  
public static void log(int sMsg) RO(TvZ0pE  
{ D<$Xy
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System.err.println(sMsg); )?! [}t  
} KvFMs\o6p  
} Q>< 0[EPj3  
<.K4JlbT  
9LJZ-/Wq  
/* [^YA=Khu  
**TestMethod.java eGL1  
*/ {-/^QX]6  
package NetFox;  AnBJ(h  
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public class TestMethod { Wi.5Y{  
t<iEj"5  
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public TestMethod() I^\&y(LJF  
{ ///xx/weblogic60b2_win.exe *XOJnyC_H  
try{ Hh;:`;}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); gY-5_Ab  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); OWq'[T4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \c,pEXG  
fileFetch.start(); I{'f|+1  
} 
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catch(Exception e){e.printStackTrace ();} aW_oD[l  
PUJ2`iP1^3  
&<TzGB*  
} OWp%v_y]  
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public static void main(String[] args) Y*oDO$6  
{ uP $Cj  
new TestMethod(); zw<p74DH  
} Ga>uFb}W~  
} K BE Ax3  
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