http断点续传简单实现（java)

/* FdKp@&O+1  
**SiteFileFetch.java $iEM$  
*/ &0It"17Ej  
package NetFox; @7"xDgA  
import java.io.*; yj `b-^$?  
import java.net.*; M9_ y>N[0  
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public class SiteFileFetch extends Thread { zob^z@2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean <[Q#}/$"  
long[] nStartPos; //开始位置 (VO) Q  
long[] nEndPos; //结束位置 w_ kHy_)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 IwZn%>1N  
long nFileLength; //文件长度 e/6WhFN#  
boolean bFirst = true; //是否第一次取文件 @rRBo:0%  
boolean bStop = false; //停止标志 ]sd|u[:k  
File tmpFile; //文件下载的临时信息 d?oupW}uu  
DataOutputStream output; //输出到文件的输出流 1C{n!l  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2rB$&>}T  
public SiteFileFetch(SiteInfoBean bean) throws IOException V.XHjHT  
{ 6A
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siteInfoBean = bean; js^@tgf$x&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); G':mc{{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); f#ID:Ap3  
if(tmpFile.exists ()) =V5<>5"M?  
{ U8c0N<j  
bFirst = false; _.' j'j%  
read_nPos(); HN7(-ml=B  
} 6m_Y%&   
else pT>[w1Kk^  
{ <?yAIhgN*  
nStartPos = new long[bean.getNSplitter()]; 8do]5FE  
nEndPos = new long[bean.getNSplitter()]; f` 2W}|(jA  
} U)=StpTT  
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} pZ/x,b#.  
7 }4T)k(a  
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public void run() 4rO07)~l  
{ >DBaKLu\  
//获得文件长度 RgHPYf{  
//分割文件 9.m_3"s  
//实例FileSplitterFetch S:v]
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//启动FileSplitterFetch线程 >~){KV1~  
//等待子线程返回 R56:}<Y,  
try{ ax[-907  
if(bFirst) 3Nd&*QSV  
{ )-xx$0mL-  
nFileLength = getFileSize(); R^iF^IB  
if(nFileLength == -1) M9.jJf  
{ "A~\$  
System.err.println("File Length is not known!"); "diF$
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} `J|bGf#  
else if(nFileLength == -2) |#D3~au   
{ Dkayk  
System.err.println("File is not access!"); EA7 8&  
} 7"yA~e,l  
else skh6L!6*<  
{ b/:9^&z  
for(int i=0;i<nStartPos.length;i++) :;cKns0OA  
{ = 7d{lK  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "a6[Fq
Ts  
} \sEq r)\k  
for(int i=0;i<nEndPos.length-1;i++) BD&JbH!(  
{ 3V?JX5X\  
nEndPos = nStartPos[i+1]; ]{jdar^
 
} 1\z5[ _  
nEndPos[nEndPos.length-1] = nFileLength; 1.+0=M[h  
} `Xc~'zG  
} 8L`J](y  
ts`c_hH,1'  
8~YhT]R=  
//启动子线程 ^q-]."W]t~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q(p]6Ha|  
for(int i=0;i<nStartPos.length;i++) H5'/i;  
{ 'h53:?~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z|^:1ov,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3,
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nStartPos,nEndPos,i); :aI[ lZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1Jg&L~Ws"  
fileSplitterFetch.start(); y2;uG2IS_g  
} yDg`9q.ckm  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eU&[^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]dHU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .t*MGUg  
nEndPos = " + nFileLength); FloCR=^H  
// fileSplitterFetch[nPos.length-1].start(); z$ZG`v>0  
~2+J]8@I]  
{U?/u93~  
//等待子线程结束 JWoNP/v6  
//int count = 0; b
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//是否结束while循环 (S$ziV  
boolean breakWhile = false; rV*9=  
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while(!bStop) V*5 ~A[r  
{ X:+lD58  
write_nPos(); Tf(-Duxz  
Utility.sleep(500); HR]*75}e  
breakWhile = true; N9
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for(int i=0;i<nStartPos.length;i++) 0Mpc#:a%1  
{ ))- B`vi  
if(!fileSplitterFetch.bDownOver) :l~Wt7R  
{ eLWD?-v%  
breakWhile = false; }G}2Y (  
break; %MGbIMpY  
} >Vc;s!R  
}
I!>pHF
4  
if(breakWhile) m<qPj"g~L  
break; {_T?0L  
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//count++; K,(37Id'  
//if(count>4) Kq&b1x  
// siteStop(); W: R2e2  
}  -i*{8t  
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System.err.println("文件下载结束！"); Qau\6p>^  
} 3pg_`  
catch(Exception e){e.printStackTrace ();} Hj\>&vMf  
} KnK8\p88\  
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//获得文件长度 F7[ 55RcP  
public long getFileSize() EAafi<n  
{ Zpc R  
int nFileLength = -1; j`tBki:  
try{ ZyAm:yO  
URL url = new URL(siteInfoBean.getSSiteURL()); jyB^a;-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1 ? be  
httpConnection.setRequestProperty("User-Agent","NetFox"); sg0HYb%_E  
1@" L  
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int responseCode=httpConnection.getResponseCode(); Zw6UH;5  
if(responseCode>=400) [C_Dv-d  
{ y/{&mo1\  
processErrorCode(responseCode); xg*)o*?  
return -2; //-2 represent access is error S 2vjjS  
} *O6q=yg;K:  
MoAZ!cF8  
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String sHeader; l@C3
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for(int i=1;;i++) &IYSoA"Nz  
{ f-]5Z
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~d5f]6#`  
//Utility.log(in.readLine()); q8 jI y@  
sHeader=httpConnection.getHeaderFieldKey(i); Igb@aGA  
if(sHeader!=null) 2x3%*r$  
{ '1rHvz`B/"  
if(sHeader.equals("Content-Length")) 1:{BC2P  
{ =6Z$nc R  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #>)OLKP  
break; ?mM6[\DFoT  
} ;<^t)8E  
} eD<Kk 4){  
else @ootKY`  
break; ]&;M78^6  
} \M(#FS  
} Q--Hf$D]H  
catch(IOException e){e.printStackTrace ();} iH&BhbRu_  
catch(Exception e){e.printStackTrace ();} U`*L`PM  
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Utility.log(nFileLength); slPLc  
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return nFileLength; tZ4Zj`x|^  
} Wbra*LNU  
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//保存下载信息（文件指针位置） *.g@6IkAQ  
private void write_nPos() %p wpRD@  
{ QVEGd"WvvO  
try{ (}^Qo^Vr  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8y$c\Eu(mF  
output.writeInt(nStartPos.length); xNLvK:@0p  
for(int i=0;i<nStartPos.length;i++) IgxZ_2hO  
{ (A<'{J#5,  
// output.writeLong(nPos); (bT3 r_  
output.writeLong(fileSplitterFetch.nStartPos); iRwlK5(&  
output.writeLong(fileSplitterFetch.nEndPos); ~]Md*F[4*e  
} Aw~N"i  
output.close(); TOUP.,f/!  
} \7l%@  
catch(IOException e){e.printStackTrace ();} &uX|Ksq  
catch(Exception e){e.printStackTrace ();} cwK+{*ZH/
 
} k2axGq  
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//读取保存的下载信息（文件指针位置） <Oyxzs  
private void read_nPos() :f9O3QA  
{ iD/
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try{ 0qdgt  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); heF<UMI  
int nCount = input.readInt(); QAI!/bB  
nStartPos = new long[nCount]; vbn'CY]QU  
nEndPos = new long[nCount]; Gd=l{
~  
for(int i=0;i<nStartPos.length;i++) (txr%Z0E  
{ 9gS.G2  
nStartPos = input.readLong(); N3C 8%  
nEndPos = input.readLong(); J3;dRW  
} w =MZi=p  
input.close(); R3`Rrj Z  
} `%a+LU2  
catch(IOException e){e.printStackTrace ();} \Gzo^w  
catch(Exception e){e.printStackTrace ();} Gb?O-z%8*  
} $IdY(f:.:5  
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private void processErrorCode(int nErrorCode) n-%8RV  
{ =2BB ~\G+  
System.err.println("Error Code : " + nErrorCode); JsA9Xdk`  
} [
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-   
//停止文件下载 "-tTN  
public void siteStop() P@RUopu,i  
{ G\HU%J  
bStop = true; r]0UF0#  
for(int i=0;i<nStartPos.length;i++) [u=DAk?8  
fileSplitterFetch.splitterStop(); K9
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} y 8./)W&/  
} TNvE26.(  
//负责部分文件的抓取 1|PmZPKq9n  
**FileSplitterFetch.java #h#Bcv0 Z  
*/ .F*2]xj@"  
package NetFox; ;~Em,M"o  
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import java.io.*; 9gz"r  
import java.net.*; qtv>`:neB  
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public class FileSplitterFetch extends Thread { limzDQ^  
1f.xZgO/2  
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String sURL; //File URL Vu6pl  
long nStartPos; //File Snippet Start Position ,Cj8{s&;
 
long nEndPos; //File Snippet End Position l5jW`cl1  
int nThreadID; //Thread's ID v7l4g&  
boolean bDownOver = false; //Downing is over }PR^Dj.  
boolean bStop = false; //Stop identical K%p*:P  
FileAccessI fileAccessI = null; //File Access interface Gn ]%'lrg'  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HxVQeyOR  
{ })l+-H"  
this.sURL = sURL; yk5T"#'+  
this.nStartPos = nStart; }UzO_&Z#6  
this.nEndPos = nEnd; <IF\;,.c  
nThreadID = id; jZ'y_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <N{pMz  
} iZ`1Dzxgk  
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public void run() Q&rf&8iH  
{ J)l]<##  
while(nStartPos < nEndPos && !bStop) `P`nqn  
{ VH{SE7  
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try{ {d;eZt `  
URL url = new URL(sURL); ,]N!I%SI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SZ
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httpConnection.setRequestProperty("User-Agent","NetFox"); =f)S=0UF  
String sProperty = "bytes="+nStartPos+"-"; VesO/xG<  
httpConnection.setRequestProperty("RANGE",sProperty); o3;u*f0rWn  
Utility.log(sProperty); X-Sso9/q.  
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InputStream input = httpConnection.getInputStream(); NRS!Ox  
//logResponseHead(httpConnection); @"~Mglgw  
%qzpt{'?<  
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byte[] b = new byte[1024]; mf26A
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int nRead; y>S.B/d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F:/R'0  
{ 5JbPB!5;  
nStartPos += fileAccessI.write(b,0,nRead); 'DQp  
//if(nThreadID == 1) TsPO+x$l  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ta+'*@V+G  
} M} IRagm  
6'Sc=;;:  
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Utility.log("Thread " + nThreadID + " is over!"); }lgqRg)F9[  
bDownOver = true; X$O,L[] 4  
//nPos = fileAccessI.write (b,0,nRead); 6,'!z ?d%  
} @=c{GAj  
catch(Exception e){e.printStackTrace ();} kWfNgu$xK  
} t|*PC  
}  ?4 `K8  
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//打印回应的头信息 ^uW!=%D  
public void logResponseHead(HttpURLConnection con) qYFol#=%  
{ GLb}_-|  
for(int i=1;;i++) ;G.m;5A
  
{ g<s[6yA  
String header=con.getHeaderFieldKey(i); y(:hN)  
if(header!=null) sBIqee'T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0EM`,?i .Q  
Utility.log(header+" : "+con.getHeaderField(header)); <69/ZI),Y{  
else /KEPPp  
break; Tk-PCra  
} Z'GOp?  
} /UjRuUC]  
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public void splitterStop() -A9 !Y{Z  
{ \n850PS  
bStop = true; oll~|J^sg  
} )_T
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} 1){1 HK  
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/* l)z15e5X  
**FileAccess.java Q8M&nf  
*//文件访问(定位，写) nJ4h9`[>V  
package NetFox; 4j!MjlG$  
import java.io.*; ?9i7+Y"  
$B4}('&4FQ  
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public class FileAccessI implements Serializable{ BzA(yCu$:  
"zw?AC6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +D4Nu+~BSN  
RandomAccessFile oSavedFile; w\_NrsO!x  
long nPos; AEi@t0By  
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public FileAccessI() throws IOException ~`hI|i<]  
{ R*TCoEKO  
this("",0); ~u8}s4  
} aQN`C{nY  
#rV=!j||  
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public FileAccessI(String sName,long nPos) throws IOException ok'0Byo  
{ )1j~(C)E8  
oSavedFile = new RandomAccessFile(sName,"rw");
;ijJ%/  
this.nPos = nPos; e=Kv[R'(M  
oSavedFile.seek(nPos); D +)6#i Y  
} S:vv*5  
{H $\,  
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public synchronized int write(byte[] b,int nStart,int nLen) `+B+RQl}[  
{ 9;Wz;p  
int n = -1; qB]z"Hfq,  
try{ dWD,iO_"@  
oSavedFile.write(b,nStart,nLen); D5T\X-+]O  
n = nLen; ; Z61|@Y  
} ]-%ZN+  
catch(IOException e) ]rn!+z  
{ WGG|d)'@  
e.printStackTrace (); B0q![  
} 8t}=?:B+{  
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return n; S97.O@V!$  
} Z6>:
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} }jiqUBn%  
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/* K^{`8E&A  
**SiteInfoBean.java Cqg}dXn'  
*/ 2y_rsu\  
package NetFox; J~gfMp.  
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public class SiteInfoBean { QJdSNkc6  
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private String sSiteURL; //Site's URL &
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private String sFilePath; //Saved File's Path V]k!]  
private String sFileName; //Saved File's Name a2=wJhk  
private int nSplitter; //Count of Splited Downloading File Y
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public SiteInfoBean() fws
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{//nSplitter的缺省值为5 ;S?1E
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//default value of nSplitter is 5 K/\#FJno  
this("","","",5); ;xB"D0~,1  
} :R_{tQ-WG  
6-KC[J^Xo  
~O1*]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0^E!P>  
{ :WA o{|&  
sSiteURL= sURL; {tR=D_5  
sFilePath = sPath; 'R]Z9h  
sFileName = sName; M5ZWcD.1  
this.nSplitter = nSpiltter; q`$QroZT"  
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E=QL4*?   
} g=U?{<8.m  
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/WHhwMc!  
public String getSSiteURL() =l7
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{ sM5 w~R>Y  
return sSiteURL; ^G2vA8%  
} hLm9"N'Pf  
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"BFW&<1  
public void setSSiteURL(String value) [tD*\\IA  
{ iBo-ANnK9  
sSiteURL = value; Uw&+zJ  
} <q[*kr  
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public String getSFilePath() l?FNYvL  
{ C>K/C!5?  
return sFilePath; s}z,{Y$-t  
} X!2|_  
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KFfwZkj{  
public void setSFilePath(String value) wj'iU&aca  
{ 0x`:jz`  
sFilePath = value; &y(aByI y  
} qyJpm{  
+z[!]^H]4  
.<NXk"\!y  
public String getSFileName() qFs<s<]  
{ =~0XdS/1  
return sFileName; ^_=0.:QaW  
} GUp51*#XR  
"mH^Owai  
^@19cU?q  
public void setSFileName(String value) =OHDp7GXO>  
{ d.}rn"(z  
sFileName = value; 8U(a&G6gn  
} F Qk;  
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}jk^M|Z"Oz  
public int getNSplitter() >{??/fBd-  
{ >b$<lo  
return nSplitter; ;<][upn  
} dY|jV}%T  
A!Yqj~  
eoL)gIM%  
public void setNSplitter(int nCount) ttKfZ0  
{ hN:Z-el  
nSplitter = nCount; lLDHx3+  
} iIF'!K=q  
} mY AFruN  
@'rO=(-b  
% (.PRRI  
/* 3PEs$m9e  
**Utility.java }GC{~ SZ4  
*/ aLq;a  
package NetFox; 0=5i\*5 p  
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public class Utility { mzw*6e2T  
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public Utility() X@G`AD'.M  
{ Sh*P^i.]+  
<|_Ey)1 6  
Lf:Z (Z>  
} b7,qzh  
0IdD  
//线程睡眠 {Eb6.  
public static void sleep(int nSecond) oaK~:'  
{ B)|s.Ez  
try{ z7_./ksQ  
Thread.sleep(nSecond); jl@8pO$  
} <>:kAT,sP  
catch(Exception e) M@K[i*e  
{ 5a~1RL  
e.printStackTrace (); BY d3rI  
} ={Hbx>p  
} Sce9R?II  
Zk[#BUA  
//日志 5jLDe~  
public static void log(String sMsg) t(yv   
{ #n7{ 3)   
System.err.println(sMsg); zN:752d^+r  
} ')aYkO{%sb  
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,rdM{ r  
public static void log(int sMsg) G~]BC#nB_  
{ 3/e !7  
System.err.println(sMsg); 1%+
^SR72  
} S=2,jPX2r  
} O`=Uq0Vv  
FdqUv%(Em  
8xX{y#  
/* 2P=;r:cx  
**TestMethod.java HHYcFoJwYN  
*/ Kv7NCpq'  
package NetFox; O?!"15  
%'HUC>ChN  
>']H)c'2  
public class TestMethod { 3{l"E(qqZ  

0{yx*}.  
^PI49iB  
public TestMethod() 9s)oC$\  
{ ///xx/weblogic60b2_win.exe 1}pR')YL[  
try{ 'FhnSNT(4=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); bsm,lx]bH^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); e'Pa@]VaC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Cw}\t!*!  
fileFetch.start(); \);rOqh  
} ;GAYcVB  
catch(Exception e){e.printStackTrace ();} W#[!8d35$  
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1
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} SMyg=B\x?7  
1dcy+ !>  
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public static void main(String[] args) kWd'gftQ  
{ t/Fe"T[,V  
new TestMethod(); UU;:x"4  
} z#4g,)ZX  
} 7'S]  
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