http断点续传简单实现（java)

/* sB^ejH  
**SiteFileFetch.java OjqT5<U  
*/ EQ|Wke  
package NetFox; L.}sN.  
import java.io.*; "*(a2k3J  
import java.net.*; ^=PY6!iW  
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public class SiteFileFetch extends Thread { .3cD.']%  
% I2JS  
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SiteInfoBean siteInfoBean = null; //文件信息Bean .WuSW[g  
long[] nStartPos; //开始位置 v-Q>I5D;:  
long[] nEndPos; //结束位置 $+Z2q<UT  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (NJ.\m  
long nFileLength; //文件长度 wwJs_f\  
boolean bFirst = true; //是否第一次取文件 j#Lj<jX!xR  
boolean bStop = false; //停止标志 #CB Kt
,  
File tmpFile; //文件下载的临时信息 jc#gn&4C  
DataOutputStream output; //输出到文件的输出流 9RkNRB)8  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9-24c  
public SiteFileFetch(SiteInfoBean bean) throws IOException lIO#)>  
{ 5j9%W18  
siteInfoBean = bean; lLglF4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); m@0> =s~.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); t=s.w(3t  
if(tmpFile.exists ()) ziM@@$.F  
{ S;%k?O7v  
bFirst = false; `9P`f4x  
read_nPos(); /g!Xe]Ss  
} :m/qR74+"  
else eIN0T;1T  
{ ,Z! I^  
nStartPos = new long[bean.getNSplitter()]; C',uY7}<  
nEndPos = new long[bean.getNSplitter()]; pr,1pqiAf  
} h|lH`m^  
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} r)Ml-r=  
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public void run() 40dwp*/!  
{ D>Rlm,U  
//获得文件长度 U%;E:|  
//分割文件 {/>uc,8O  
//实例FileSplitterFetch >*n4j:  
//启动FileSplitterFetch线程 0W+RVp=TL1  
//等待子线程返回 [8oX[oP  
try{ wL6G&6]</W  
if(bFirst) S?OCy4dk:  
{ Z/4bxO=m  
nFileLength = getFileSize(); %5@> nC?`[  
if(nFileLength == -1) :1@jl2,  
{ ];N/KHeZ  
System.err.println("File Length is not known!"); PpF`0w=1%l  
} LZE9]Gd  
else if(nFileLength == -2) jJ,y+o  
{ U:[CcN/~3  
System.err.println("File is not access!"); 9JJ6$cLF  
} fRkx ^u P  
else 6k<3,`VV|  
{ x;LO{S4Z  
for(int i=0;i<nStartPos.length;i++) : Cli8#  
{ Wc;N;K52   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); UDnCHGq  
} H6`zzH0"  
for(int i=0;i<nEndPos.length-1;i++) eW}-UeT  
{ sN5Mm8~  
nEndPos = nStartPos[i+1]; lZ <D,&  
} pigu]mj  
nEndPos[nEndPos.length-1] = nFileLength; SxcE@WM  
} wub7w#  
} Be<bBKQb  
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//启动子线程 Lc "{eP
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ZU2D.Kf_:  
for(int i=0;i<nStartPos.length;i++) wnQi5P+  
{ >enP~uW[#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,_=LV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?`6Mfpvj96  
nStartPos,nEndPos,i); &>K|F >7q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IMpL+W.  
fileSplitterFetch.start(); ~SsfkM"  
} |t;Ktl  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T| R!Aw
.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); nB5^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g9d/nRX&  
nEndPos = " + nFileLength); D}-HWJQA3  
// fileSplitterFetch[nPos.length-1].start(); P*hYh5a  
!FB2\hiM  
1CV?  
//等待子线程结束 :R$v7{1  
//int count = 0; XIl#0-E0X  
//是否结束while循环 '
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boolean breakWhile = false; N4{g[[ T  
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while(!bStop) jW[
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{ &?}h)
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write_nPos();
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Utility.sleep(500); Q trU_c2k  
breakWhile = true; XjxI@VXzUV  
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for(int i=0;i<nStartPos.length;i++) ^1aY,6I:  
{ t_(Se  
if(!fileSplitterFetch.bDownOver) :r{W)(mm  
{ _eH@G(W(  
breakWhile = false; gb[.Ww  
break;  ;CV'
 
} RtDTcaW/  
} g|4>S<uC  
if(breakWhile) pF}E`U=Z  
break; N~S#(.}[  
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hl DU.k  
//count++; $d&7q5[  
//if(count>4) Vgy12dE  
// siteStop(); 7~QAprwVS  
} HPo><u  
/^WawH6)6  
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System.err.println("文件下载结束！"); ww'B!Ml>F  
} ,I,Zl.5  
catch(Exception e){e.printStackTrace ();} [g+WL\1  
} G,(Xz"`,  
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//获得文件长度 Kf$6D 79#  
public long getFileSize() \fYPz }wt  
{ X[?E{[@Z  
int nFileLength = -1; [:A">eYI  
try{ 2%`8  
URL url = new URL(siteInfoBean.getSSiteURL()); {WeRFiQ?-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jX t5.9 t  
httpConnection.setRequestProperty("User-Agent","NetFox"); \oP  
?b(DDQMf  
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int responseCode=httpConnection.getResponseCode(); +hH7|:JQ  
if(responseCode>=400) &@PAv5iNf  
{ A!$sOp  
processErrorCode(responseCode); j1ap,<\.k  
return -2; //-2 represent access is error 90wnwz  
} =~dsIG  
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String sHeader; X'2%'z<  
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for(int i=1;;i++) )>;387'Y  
{ CKU)wJ5t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); S@4bpnhK  
//Utility.log(in.readLine()); Nvd(Tad  
sHeader=httpConnection.getHeaderFieldKey(i); .Lm`v0'w  
if(sHeader!=null) c-Qa0Q  
{ }j\8|UG  
if(sHeader.equals("Content-Length")) V9`jq$  
{ !__^M3S,k  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mxwG~a'_  
break; sq8O+AWl  
} h{?f uoZj%  
} 4k6:   
else H;FzWcm  
break; P1`YbLER5  
} QX.U:p5C  
} 8yuTT^  
catch(IOException e){e.printStackTrace ();} Imo?)dYK  
catch(Exception e){e.printStackTrace ();} XhOg>  
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Utility.log(nFileLength); u:^9ZQ+  
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return nFileLength; RF\h69]:I  
} s-l3_210  
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//保存下载信息（文件指针位置） n+Ng7  
private void write_nPos() OoZv\"}!_  
{ u$^r(.EV  
try{ :QMpp}G  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9*CRMkPrd  
output.writeInt(nStartPos.length); %V-Hy;V  
for(int i=0;i<nStartPos.length;i++) C{V,=Fo^  
{ ;9uDV-"  
// output.writeLong(nPos); }7qboUGe  
output.writeLong(fileSplitterFetch.nStartPos); \F7NuG:m,  
output.writeLong(fileSplitterFetch.nEndPos); W:2j.K9!  
} 1.a:iweN  
output.close(); tA K=W$r  
} :,'.b|Tl.b  
catch(IOException e){e.printStackTrace ();} :&s8G*  
catch(Exception e){e.printStackTrace ();} ]TsmWob  
} `O?j -zR  
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c>#3{}X|x%  
//读取保存的下载信息（文件指针位置） 1EliR uJ  
private void read_nPos() y*I,i*iv  
{ <?!%dV{z  
try{ z,SNJIsx  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); IXR%IggJA  
int nCount = input.readInt(); jZqCM{  
nStartPos = new long[nCount]; \YH*x`  
nEndPos = new long[nCount]; }y%mG&KSz  
for(int i=0;i<nStartPos.length;i++) XBTjb  
{ P0-K/_g  
nStartPos = input.readLong(); \Iz-<:gA'  
nEndPos = input.readLong(); t y%Hrw  
} ,k,+UisG  
input.close(); LlbE]_Z!U%  
} VS5D)5w#  
catch(IOException e){e.printStackTrace ();} Pm|S>r  
catch(Exception e){e.printStackTrace ();} NF_[q(k'  
} 2K{)8;^  
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private void processErrorCode(int nErrorCode) c+UZ UgP  
{ ~fz9PoC  
System.err.println("Error Code : " + nErrorCode); I -V=Z:  
} z*/}rk4i  
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//停止文件下载 t\-;n:p-  
public void siteStop() sTECNY=l  
{ EB5^eNdL  
bStop = true; (gUxS.zU  
for(int i=0;i<nStartPos.length;i++) oX6()FR  
fileSplitterFetch.splitterStop(); <A] Kg  
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} XC[bEp$  
} F2$?[1^f  
//负责部分文件的抓取 y~rtYI  
**FileSplitterFetch.java G2FD'Sf  
*/ >]?!9@#IH  
package NetFox; ?"T *{8  
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import java.io.*; R|!4k
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import java.net.*; N-Sjd%Z  
(.9H1aO46|  
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public class FileSplitterFetch extends Thread { 3x E^EXV  
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String sURL; //File URL /SJI ~f+$  
long nStartPos; //File Snippet Start Position qk!,:T  
long nEndPos; //File Snippet End Position S~.%G)R  
int nThreadID; //Thread's ID :ZU
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boolean bDownOver = false; //Downing is over 7iH%1f  
boolean bStop = false; //Stop identical gnZc`)z  
FileAccessI fileAccessI = null; //File Access interface $Q56~AP  
%Yny/O\e%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =b#,OXQ  
{ s^-o_K\*c  
this.sURL = sURL; o1rH@D6/-  
this.nStartPos = nStart; :74G5U8%  
this.nEndPos = nEnd; ~>5
 
nThreadID = id; AF"XsEt.e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Rnk&:c  
} qUG)+~g`  
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{
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public void run() XM?C7/^k  
{ ag"Nf-o/Y  
while(nStartPos < nEndPos && !bStop) $WZHkV  
{ Z`{GjV3%wH  
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try{ 78FK{Cr  
URL url = new URL(sURL); Cg%}=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n,%/cUl  
httpConnection.setRequestProperty("User-Agent","NetFox"); jg=}l1M"  
String sProperty = "bytes="+nStartPos+"-"; wXUgxa  
httpConnection.setRequestProperty("RANGE",sProperty); LKu ,H  
Utility.log(sProperty); @i@f@.t  
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3>buZ6vh  
InputStream input = httpConnection.getInputStream(); 4>te>[  
//logResponseHead(httpConnection); j79$/ Ol  
C: a</Sl  
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byte[] b = new byte[1024]; k3r<']S^  
int nRead; Eilo;-El  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qJEtB;J'  
{ ~DUOL~E  
nStartPos += fileAccessI.write(b,0,nRead); ~X1<x4P\  
//if(nThreadID == 1) ^97\TmzP{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r[RO"Ej"  
} U7d05y'  
lX%e  
iLJBiZ+  
Utility.log("Thread " + nThreadID + " is over!"); Ox"SQ`nSj'  
bDownOver = true; %1%@L7wP>  
//nPos = fileAccessI.write (b,0,nRead); r*W&SU9Z  
} &W-1W99auE  
catch(Exception e){e.printStackTrace ();} ]gB:ht  
} q%8Ck)xz  
} \Gz 79VW  
9c=`Q5  
6yXMre)YV  
//打印回应的头信息 Mg=R**s1x%  
public void logResponseHead(HttpURLConnection con) 8Z(\iZ5Rgj  
{ ~`o%Y"p%rv  
for(int i=1;;i++) uZ(,7>0  
{ t-$Hti7Lk  
String header=con.getHeaderFieldKey(i); lhduK4u  
if(header!=null) qre(3,VE5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); IyGW>g6_.  
Utility.log(header+" : "+con.getHeaderField(header)); _&/2-3]\B  
else 6eAJ>9@x  
break; =FXq=x%9+  
} t{Gc,S!]5  
} yo"!C?82=  
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public void splitterStop() Gque@u  
{ </)QCl'd  
bStop = true; @y{ f>nm  
} wxo{gBq  
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3\&I
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} g2W ZW#a)  
7?"-NrW~  
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/* 2U`g[1  
**FileAccess.java `NARJ9M   
*//文件访问(定位，写) =1Tn~)^O  
package NetFox; wb/@g=`d  
import java.io.*;
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public class FileAccessI implements Serializable{ DjQgF=;  
RS /*Dp^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =!P$[pN2  
RandomAccessFile oSavedFile; @1iH4RE*  
long nPos; \6K1Z!*;  
@RFJe$%  
u13v@<HGc  
public FileAccessI() throws IOException _$BH.I  
{ Ej/P:nB  
this("",0); *K2fp=Ns  
} 8Xk,Nbcqt  
qBXIR}  
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public FileAccessI(String sName,long nPos) throws IOException 8VR! Y0`e  
{ hR%2[lBn!]  
oSavedFile = new RandomAccessFile(sName,"rw"); 3[}w#n1  
this.nPos = nPos; V.Qy4u7m  
oSavedFile.seek(nPos); #FsoK*F  
} ,ku3;58O<  
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public synchronized int write(byte[] b,int nStart,int nLen) WTQd}f  
{ <<[\ Rv  
int n = -1; -JfO} DRI  
try{ A6%~
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oSavedFile.write(b,nStart,nLen); XZ[3v9?&n  
n = nLen; MFO1v%m  
} !DNk!]|  
catch(IOException e) LXx`Vk>ky  
{ SH#!Y  
e.printStackTrace (); ]8ob`F`m,  
} #i0f}&
 
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return n; :}p<Hq 8Z  
} 8I,/ysT:  
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} tboc7Hor4  
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/* n`2LGc[rP  
**SiteInfoBean.java `]4bH,%~  
*/ T+~ _D  
package NetFox; AN 'L- E  
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public class SiteInfoBean { px=r~8M9}  
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private String sSiteURL; //Site's URL g RBbL1  
private String sFilePath; //Saved File's Path Tl`HFZQ1  
private String sFileName; //Saved File's Name f4r)g2Zb[  
private int nSplitter; //Count of Splited Downloading File h^=9R6im  
[V_\SQV0  
+DA,|~k_  
public SiteInfoBean() sRDxa5<MD  
{//nSplitter的缺省值为5 rhA>;9\  
//default value of nSplitter is 5 "%]vSr  
this("","","",5); Q2nqA1sRk  
} X6k-a;  
+EE(d/f  
W+D{4:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) RLr^6+v)U  
{ ?-D'xqc  
sSiteURL= sURL; Spt;m0W90  
sFilePath = sPath; +W[NgUrGJ  
sFileName = sName; mr\C  
this.nSplitter = nSpiltter; [3fmhc  
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} o`<ps$yT  
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public String getSSiteURL() $|pD}  
{ )G=hgqy  
return sSiteURL; w-?|6I}T  
} "6zf-++%  
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public void setSSiteURL(String value) o%.0@W  
{ YH/3N(],  
sSiteURL = value; y(h"0A1lW  
} yy#4DYht  
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)2mvW1M=7;  
public String getSFilePath() xI(Y}>  
{ Yo;Mexo!  
return sFilePath; _8'z"wF  
} _W^{,*p  
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wwVg'V;  
public void setSFilePath(String value) >[a&,gS  
{ !R@s+5P)U  
sFilePath = value; 2JX@#vQ4  
} D~LU3#n  
VSW"/{Lp  
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public String getSFileName() bFtzwa5Gc  
{ J'#R9NO<  
return sFileName; vD'YLn%Q  
} qF57T>v|  
)9'Zb`n  
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public void setSFileName(String value) N,~"8YSo  
{ %"g;K  
sFileName = value; 3?:?dy(3z  
} z((9vi W  
)h,
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j^qI~|#  
public int getNSplitter() 3}25=%;[  
{ n+%tu"e  
return nSplitter; +#MQ8d  
} fZF.eRP'  
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G0&'B6I>  
public void setNSplitter(int nCount) Zq\Vq:MX  
{ &=`6- J  
nSplitter = nCount; z)0%gd|  
} $mLiEsJ  
} I^itlQ  
BOf)27)  
$ Ov#^wfA  
/* Z&j?@k,k  
**Utility.java |VE*_G  
*/ ^dCSk==  
package NetFox; TATH,Sz:x  
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public class Utility { V^5Z9!
  
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public Utility() f+W8Gszi  
{ ruTj#tWSo  
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W9%B9~\G;+  
} '1te(+;e@  
n,.t~  
//线程睡眠 k%fy  
public static void sleep(int nSecond) ^#)M,.G^  
{ EaXDY<  
try{ ug.'OR  
Thread.sleep(nSecond); os~}5QJ  
} k:k!4  
catch(Exception e) 
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{ ^":Dk5gl  
e.printStackTrace (); +K
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} 95X!{\  
} k=8LhO  
;$>wuc'L  
//日志 ;_<K>r*  
public static void log(String sMsg) gP 6`q  
{ c0M>CaKD  
System.err.println(sMsg); J0a#QvX!  
} z(dX<  
Zk#?.z}  
>HlQ+bl$xw  
public static void log(int sMsg) v'W`\MKY)  
{ oYNp0Hc  
System.err.println(sMsg); $dgez#TPL  
} .?CumaU  
} lM'yj}:~  
RFzMah?Q=j  
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/* 1ps_zn(  
**TestMethod.java x.-d>8-!]c  
*/ V|mz]H#|  
package NetFox; \NI0rL  
8`S6BkfC|  
PS${B   
public class TestMethod { p&4#9I5  
@mu2,%  
1[Ffl^\ARp  
public TestMethod() {P>%l\?  
{ ///xx/weblogic60b2_win.exe XOi[[G}  
try{ m"RE[dQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >iIUS  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ":upo/xN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Wy.Xx-3W  
fileFetch.start();  T24?1  
} J4;Fk  
catch(Exception e){e.printStackTrace ();} ?=X_a{}/  
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&$ /}HND  
} NDaM;`  
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public static void main(String[] args) CWk65tcF  
{ b+`mh  
new TestMethod(); >4lT0~V/  
} _Z|3qQ  
} rJ UXA<:2  
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