http断点续传简单实现（java)

/* D1T@R)j  
**SiteFileFetch.java r>t1 _b+nu  
*/ 8@\7&C(g17  
package NetFox; jndGiMA  
import java.io.*; ?Bx./t><  
import java.net.*; ]A+o>#n}x  
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public class SiteFileFetch extends Thread { 5V5w:U>_z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #Dy?GB08  
long[] nStartPos; //开始位置 h~}.G{"  
long[] nEndPos; //结束位置 l#qv 5f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^@6q  
long nFileLength; //文件长度 D E/:['  
boolean bFirst = true; //是否第一次取文件 E"PcrWB&  
boolean bStop = false; //停止标志 Xm!-~n@-m7  
File tmpFile; //文件下载的临时信息 *?% k
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DataOutputStream output; //输出到文件的输出流 egR-w[{  
!8RwO%c(  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） tWPO]3hW  
public SiteFileFetch(SiteInfoBean bean) throws IOException <L0#O(L  
{ r4XH =  
siteInfoBean = bean; G| m4m.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5iX! lAFJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~)]} 91p  
if(tmpFile.exists ()) m$2<`C=  
{ q1{H~VSn"  
bFirst = false; .*/Fucr  
read_nPos(); nk=$B(h  
} \2e0|)aF6  
else elPE%'  
{ S::>N.y  
nStartPos = new long[bean.getNSplitter()]; $)Bg JDr  
nEndPos = new long[bean.getNSplitter()]; \_BkY%a
 
} ;H0{CkH  
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} gAbD7SE  
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public void run() 2N [=  
{ sM2MLh'D  
//获得文件长度 b/("Y.r=  
//分割文件 6W2hr2Zy9  
//实例FileSplitterFetch $'wq1u  
//启动FileSplitterFetch线程  %Y nmuZ  
//等待子线程返回 ``K#}3  
try{ Xyx"A(v^l  
if(bFirst) q6d~V]4:  
{ ,FSrn~-j9  
nFileLength = getFileSize(); Dm0a.J v  
if(nFileLength == -1) n6Z|Q@F  
{ 
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System.err.println("File Length is not known!"); a[!%Ld  
} N"7]R[*  
else if(nFileLength == -2) t0E51Ic@  
{ 0\QR!*'$  
System.err.println("File is not access!"); nms8@[4-  
} m_NCx]#e   
else EG<s_d?  
{ 8At<Wic  
for(int i=0;i<nStartPos.length;i++) ['qnn|  
{ 3lxc4@Zmd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L"+
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} 2f:^S/.A  
for(int i=0;i<nEndPos.length-1;i++) ]ZoPQUS?  
{  $)~   
nEndPos = nStartPos[i+1]; ef"?|sn  
} I/J7rkf  
nEndPos[nEndPos.length-1] = nFileLength; sy5 Fn~\R  
} bZwnaM4"F  
} ~l E _L1-c  
b{7E;KyY,  
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//启动子线程 2@j";
+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6sfwlT  
for(int i=0;i<nStartPos.length;i++) oYM3Rgxf9Q  
{ hVpCB,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TD@v9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :$3oFN*g  
nStartPos,nEndPos,i); WgQBGch,!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kAYb!h[`  
fileSplitterFetch.start(); e /K#>,  
} GIwh@4;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8(U{2B8>\%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `CE^2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", J>vMo@  
nEndPos = " + nFileLength); <'U]`Lp  
// fileSplitterFetch[nPos.length-1].start(); |UnUG  
|bv,2uWz  
bCv{1]RC2  
//等待子线程结束
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//int count = 0; n$L51#'  
//是否结束while循环 @ EuFJ=h  
boolean breakWhile = false; LJlZ^kh  
aBuoHdg;  
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while(!bStop) S_(d9GK<  
{ >h~IfZU1  
write_nPos(); je,}_:7  
Utility.sleep(500); = "ts`>  
breakWhile = true; +a@GHx4-  
}WLh8i?_  
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for(int i=0;i<nStartPos.length;i++) +~zXDBS9  
{ ~`MS~,,  
if(!fileSplitterFetch.bDownOver) %r{3wH#D@  
{ 7*o*6,/  
breakWhile = false; L:nXWz  
break; v-j3bB  
} OW;tT=ql  
} o89( h!  
if(breakWhile) z9/G4^qF  
break; qQ[b VD\*  
3Hi+Z}8  
)$GIN/i  
//count++; 5N$E()m$  
//if(count>4) yBpk$  
// siteStop(); <!d"E@%v@  
} "8f?h%t  
j V3)2C}  
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System.err.println("文件下载结束！"); E$s/]wnr[  
} kh$_!BT  
catch(Exception e){e.printStackTrace ();} #Il_J\#  
} PG%0yv%  
R{YzH56M  
IXLO
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//获得文件长度 +FG$x/\*0  
public long getFileSize() NcS.49  
{ ;Y9=!.Ak0y  
int nFileLength = -1; ff?t[GS  
try{ :Sg&0Wj+#j  
URL url = new URL(siteInfoBean.getSSiteURL()); .>g1$rj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,$*IzL~  
httpConnection.setRequestProperty("User-Agent","NetFox"); )EM7,xMz  
eP1nUy=T  
5/><$06rq  
int responseCode=httpConnection.getResponseCode(); H;ZHqcUX  
if(responseCode>=400) j-@kW'K  
{ @r
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processErrorCode(responseCode); vYmSKS  
return -2; //-2 represent access is error gApoX0nrv  
} 0Wvq>R.(]7  
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String sHeader; 5FKBv e@  
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for(int i=1;;i++) x+5p1sv6  
{ od<b!4k~s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  cc=gCE  
//Utility.log(in.readLine()); lU]un&[N  
sHeader=httpConnection.getHeaderFieldKey(i); rsNf$v-*  
if(sHeader!=null) BbOu/i|  
{ or*HC&c7  
if(sHeader.equals("Content-Length")) @`"AHt  
{ %
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _o6G6e,  
break; ^ZeJ[t&!#  
}
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} n`Z"rwKmNw  
else f'(l&/4z{  
break; GOy%^:Xd  
} 2RtHg_d_l  
} k8nLo.O  
catch(IOException e){e.printStackTrace ();} qem(s</:  
catch(Exception e){e.printStackTrace ();} bUy,5gk-  
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Utility.log(nFileLength); `iKj
 
* A|-KKo\  
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return nFileLength; oP?YA-#nc  
} OKOu`Hz@  
Z
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H[Q_hY[>V  
//保存下载信息（文件指针位置） kYwb -;  
private void write_nPos() 1$lh"fHU  
{ FN[R(SLbL  
try{ Zi$ziDz&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `b5 @}',  
output.writeInt(nStartPos.length); >RI>J.~  
for(int i=0;i<nStartPos.length;i++) GyI-)BlDC  
{ .aOnGp  
// output.writeLong(nPos); {i~8 :  
output.writeLong(fileSplitterFetch.nStartPos); )vB2!H/  
output.writeLong(fileSplitterFetch.nEndPos); x|64l`Vp(:  
} vEe NW  
output.close(); V}w;Y?]J  
} aT  l c  
catch(IOException e){e.printStackTrace ();} M[

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catch(Exception e){e.printStackTrace ();} xG&SX#[2  
} +#J,BKul  
\$*$='6"  
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//读取保存的下载信息（文件指针位置） Kr`]_m  
private void read_nPos() 4pU>x$3$  
{ D<{{ :7n  
try{ !G5a*8]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~|Y>:M+0Z  
int nCount = input.readInt(); &:B<Q$g#  
nStartPos = new long[nCount]; B#%;Qc  
nEndPos = new long[nCount]; ._:nw=Y0<}  
for(int i=0;i<nStartPos.length;i++) g&/p*c_  
{ f3*?MXxb16  
nStartPos = input.readLong(); l7[7_iB&E  
nEndPos = input.readLong(); .3pbu
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} W1aa:hEf  
input.close(); C.MoKa3  
} C&\5'[*  
catch(IOException e){e.printStackTrace ();} YA(@5CZ  
catch(Exception e){e.printStackTrace ();} +A_J1iJ<  
} )x,8D ~p'  
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private void processErrorCode(int nErrorCode) @R~5-m  
{ 36m5bYMd)  
System.err.println("Error Code : " + nErrorCode); N6oq90G  
} #1-xw~_  
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6@  
//停止文件下载
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public void siteStop() a@d=>CT$  
{ .4.pJbOg  
bStop = true; ({}(qm  
for(int i=0;i<nStartPos.length;i++) ewsKH\#  
fileSplitterFetch.splitterStop(); ]LPQYL  
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{  
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} xom<P+M!|  
} 0pe3L  
//负责部分文件的抓取 +0z 7KO%^^  
**FileSplitterFetch.java d?,M/$h  
*/ 0\{BWNK  
package NetFox; D]! aT+  
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{.e=qQ%P5)  
import java.io.*; :q##fG'm/  
import java.net.*; woH)0v  
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public class FileSplitterFetch extends Thread { s0UFym8  
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String sURL; //File URL |w}w.%  
long nStartPos; //File Snippet Start Position .]4W!])9  
long nEndPos; //File Snippet End Position em@EDMvI  
int nThreadID; //Thread's ID jZfx Jm  
boolean bDownOver = false; //Downing is over JwnAW}=  
boolean bStop = false; //Stop identical f6<g3Q7Mu  
FileAccessI fileAccessI = null; //File Access interface U4?(A@z9^  
4_M>OD/"  
/BKe+]dS*  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !v#xb3"/  
{ fg%&N2/(.B  
this.sURL = sURL; _,h@:Xij  
this.nStartPos = nStart; VU|dV\>  
this.nEndPos = nEnd; j|.} I  
nThreadID = id; )YW<" $s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 79J-)e9  
} 92W&x'  
DLE8+NV8   
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public void run() WUdKLx%F  
{ e=P  
while(nStartPos < nEndPos && !bStop) J a,d3K  
{ r~[vaQQ6L  
m,LG=s  
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try{ d=.2@Ry  
URL url = new URL(sURL); 3Q}$fQ&S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !,$i6gm  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^u)z{.z'H/  
String sProperty = "bytes="+nStartPos+"-"; qf'm=efRyu  
httpConnection.setRequestProperty("RANGE",sProperty); uw\1b.r'B  
Utility.log(sProperty); {WN(&eax  
[ANuBNF  
w6|9|f/  
InputStream input = httpConnection.getInputStream(); 6x{<e4<n  
//logResponseHead(httpConnection); Tz&Y]#h_  
I lR\  #  
?gGt2O1J  
byte[] b = new byte[1024]; yQS+P8x&|]  
int nRead; <M
?:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |Q~cX!;  
{ 6bc337b  
nStartPos += fileAccessI.write(b,0,nRead); ^:, l\Y  
//if(nThreadID == 1) RH0>ZZR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c2l_$p  
} i yYJR  
2pHR_mrb  
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Utility.log("Thread " + nThreadID + " is over!");  I 1d0iU  
bDownOver = true; yKagT$-  
//nPos = fileAccessI.write (b,0,nRead); W3W'
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} }`VDD?M  
catch(Exception e){e.printStackTrace ();} <c[U#KrvJ  
} wHjLd$ +o  
} !#ri5{od  
=Yo1v=wxN  
eS/B24;*  
//打印回应的头信息 tU wRE|_  
public void logResponseHead(HttpURLConnection con) 9Vuq,dv  
{ pC,o2~%{  
for(int i=1;;i++) 3{%LS"c  
{ rf+:=|/_3  
String header=con.getHeaderFieldKey(i); RNV

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if(header!=null) &>WWzikB*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "e3["'  
Utility.log(header+" : "+con.getHeaderField(header)); "tit\a6\(  
else \h
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break; x LBQ  
} 6Sj6i^"  
} ',7??Q7j&v  
?VU(Pq*`  
.k{ j]{k  
public void splitterStop() u#7+U\  
{ Q~D`cc|]  
bStop = true; IHfzZHy  
} z(uZF3  
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} WnFG{S{s  
!33#. @[  
gCd`pi 8  
/* `[#x_<\t  
**FileAccess.java :m=m}3/:  
*//文件访问(定位，写) OIHz I2{  
package NetFox; u]^N&2UW  
import java.io.*; [mxTa\  
/76 1o\Q  
/(I*,.d  
public class FileAccessI implements Serializable{ 8qi
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x Ha=3n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !%<
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RandomAccessFile oSavedFile; kU5.iK'  
long nPos; 4Q=ftY<  
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public FileAccessI() throws IOException egR9AEJvz  
{
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this("",0); s}&bJ"!Z  
} =!Vf  
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public FileAccessI(String sName,long nPos) throws IOException 9n]|PE
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{ QlFZO4 P3|  
oSavedFile = new RandomAccessFile(sName,"rw"); +YOKA*  
this.nPos = nPos; qJ!Z~-hS  
oSavedFile.seek(nPos); 39U5jj7i  
} +eQe%U  
fHrt+_Zn|  
6}~pq1IF{  
public synchronized int write(byte[] b,int nStart,int nLen) Y/TlE?  
{ gsar[gZ  
int n = -1; sH,kW|D  
try{ gMWBu~;!  
oSavedFile.write(b,nStart,nLen); AEmNHO@%q  
n = nLen; >M%\T}5  
} j83? m  
catch(IOException e) {eJt,[Y *  
{ X C86-b)E  
e.printStackTrace (); z@s5m}  
} n;HHogA  
r,SnXjp@  
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return n; Z!d7&T}  
} m4K* <  
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} 5/",<1  
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/* x"kjs.d7[<  
**SiteInfoBean.java J;t 7&Zpe  
*/ }F6<w{|  
package NetFox; EO|:
FcW  
rr`;W}3  
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public class SiteInfoBean { PW(\4Q\  
0oA{Jix  
;?fS(Vz~  
private String sSiteURL; //Site's URL .@)mxC:\K9  
private String sFilePath; //Saved File's Path lA!"z~03*  
private String sFileName; //Saved File's Name 5cr(S~Q;  
private int nSplitter; //Count of Splited Downloading File 9L0GLmLk1u  
4rK{-jvh>m  
D(W,yq~7uY  
public SiteInfoBean() `Ycf]2.,$
 
{//nSplitter的缺省值为5 R9We/FhOY  
//default value of nSplitter is 5 p1pQU={<  
this("","","",5); u*S=[dq  
} qIUfPA=/_  
%A1@&xrbl  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gie
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{ Z0!5d<  
sSiteURL= sURL; L(S'6z~_9  
sFilePath = sPath; z2gk[zY&  
sFileName = sName; s1Ok|31|  
this.nSplitter = nSpiltter; Bm$"WbOq*R  
5 *}R$  
&adI (s~  
} d9*hBm  
<>eOC9;VY  
0Q,g7K<d  
public String getSSiteURL() }uHrto3M  
{ a?} .Fs  
return sSiteURL; zIC;7 5#  
} ',3HlOJ:  
gwrYLZNGI  
p;)"  
public void setSSiteURL(String value) %)jxW
{  
{ rVvR!"//yH  
sSiteURL = value; 5
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} @5
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public String getSFilePath() CHd9l]Rbe  
{ I3 =#@2  
return sFilePath; X5fmz%VK@  
} Hjv
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 ~I/@i  
>FjR
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public void setSFilePath(String value) 7qOa ;^T  
{ 6%`&+Lq  
sFilePath = value; 'C$XS>S  
} #1c]PX  
vr#+0:|  
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public String getSFileName() T J^u"j-'  
{ dF0,Y?  
return sFileName; a)Q!'$"'  
} |yyO q  
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@J{m@ji{  
public void setSFileName(String value) R_]{2~J+  
{ iUMY!eqp  
sFileName = value; K/m3  
} VUTacA Y>L  
?7:KphFX)  
mS>xGtD&K  
public int getNSplitter() -aRU]kIf  
{ :.(;<b<\  
return nSplitter; uZa9zs=}c  
} I{JU-Jk|  
4p%A8%/q  
{ pu85'DV  
public void setNSplitter(int nCount) ERwHLA  
{ V^y^ ;0I}[  
nSplitter = nCount; ')a(.f  
} 5vo.[^ty  
} j.a`N2]WE  
jA".r'D%  
ZnFi<@UB)  
/* }nt* [:%  
**Utility.java wIkN9 f  
*/ &<zd.~N"  
package NetFox; gh`m*@  
`&0Wv0D0  
!$2Z-!  
public class Utility { $'W}aER  
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public Utility() "G>3QL+O|  
{ >+. (r]  
[{4MR%--  
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} EM>}0V  
%h1N3\y9i(  
//线程睡眠 yx V:!gl  
public static void sleep(int nSecond) IUR<.Y`  
{ t+oJV+@  
try{ Y|8vO  
Thread.sleep(nSecond); \xg]oKbn  
} Y`+=p@2O2o  
catch(Exception e) ,mRyQS'F  
{ Bq/:Nd[y  
e.printStackTrace (); 7+./zN  
} Vcd.mE(t%  
} $/Aj1j`"9+  
5cx#SD&5/  
//日志 }@if6(0  
public static void log(String sMsg) Qf@I)4
'  
{ u3Gjg{-N7  
System.err.println(sMsg); $R<Me  
} nRd)++  
4|A>b})H  
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public static void log(int sMsg) FP[!BUOf"  
{ cj11S>D  
System.err.println(sMsg); CJ}5T]WZ  
} @FdSFQ/9  
} #plY\0E@  
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a>\vUv*  
/* Ym;*Y !~[  
**TestMethod.java cqxVAzb  
*/ UH7jP#W%=  
package NetFox; Z{?G.L*/  
s3Cc;#  
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public class TestMethod { = k\J<  
:qC'$dO!
 
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public TestMethod() +{
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{ ///xx/weblogic60b2_win.exe s/089jlc  
try{ )O:0]=#))  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 26CS6(sn  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6(PM'@i  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0'nikLaKy  
fileFetch.start(); tHLrhH<w  
} ;c$J=h]  
catch(Exception e){e.printStackTrace ();} VK@!lJu!  
 Q1@A2+ c  
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} k4 F"'N  
Cu6%h>@K$  
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public static void main(String[] args)  TX  
{ SwZA6R&  
new TestMethod(); e{Z &d  
} Haqm^Ky$  
} >:lnt /N3  
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