http断点续传简单实现（java)

/* h?'~/@  
**SiteFileFetch.java U*4r<y9R  
*/ %y_{?|+  
package NetFox; L Iz<fB  
import java.io.*; * o{7 a$V  
import java.net.*; Kk`LuS?  
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public class SiteFileFetch extends Thread { bEm9hFvd  
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SiteInfoBean siteInfoBean = null; //文件信息Bean LwYWgT
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long[] nStartPos; //开始位置 7-gT:  
long[] nEndPos; //结束位置 Q_>W!)p Gz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 TJCE6QG  
long nFileLength; //文件长度 3$wK*xK  
boolean bFirst = true; //是否第一次取文件 N "}N>xe2  
boolean bStop = false; //停止标志 9l(T>B2a  
File tmpFile; //文件下载的临时信息 H*e+ 2  
DataOutputStream output; //输出到文件的输出流 />6ECT  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `Qjs{H  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0` .5gxm  
{ R0%M9;>1
 
siteInfoBean = bean; oKb"Ky@s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?}uuTNLl)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hD=.rDvO  
if(tmpFile.exists ()) <{GVA0nr  
{ tv26eK 38  
bFirst = false;  +IO>%  
read_nPos(); z;!"i~fFK  
} *MB>,HU  
else ()48>||  
{ \5 rJ  
nStartPos = new long[bean.getNSplitter()]; {`Gd  
nEndPos = new long[bean.getNSplitter()]; 4Y$\QZO  
} S'5Zy} +x  
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} a{
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public void run() 6y~F'/ww  
{ z}B39L  
//获得文件长度 HC/z3b;  
//分割文件 "L:4 7!8  
//实例FileSplitterFetch DL?nvH  
//启动FileSplitterFetch线程 p |1u,N  
//等待子线程返回 #,u|*O:  
try{ Q{RmE:  
if(bFirst) B+snHabS6  
{ +l/v`=C  
nFileLength = getFileSize(); bD{k=jum  
if(nFileLength == -1) Ff%V1BH[  
{ c%J6!\
 
System.err.println("File Length is not known!"); C!*.jvhT  
} dw3Hk$"h  
else if(nFileLength == -2) P=5+I+  
{ ~e 1l7H;  
System.err.println("File is not access!"); 9MYk5q.X:  
} Cq"KKuf  
else CMaph  
{ 1XMR7liE  
for(int i=0;i<nStartPos.length;i++) <"J]u@|  
{ `(sb  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <aJQV)]\  
} $Sgf jm  
for(int i=0;i<nEndPos.length-1;i++) "(^XZAU#W  
{ $+!dP{  
nEndPos = nStartPos[i+1]; |zYOCDFf  
}  OegeZV  
nEndPos[nEndPos.length-1] = nFileLength; >F7w]XH  
} ds(?:zx#  
}  b.&WW  
N8b\OTk2  
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//启动子线程 TZAd{EZa  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; DPTk5o[  
for(int i=0;i<nStartPos.length;i++) DAB9-[y+  
{ /Vn>(;lo  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?)xIn)#ls  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), " B#|C'  
nStartPos,nEndPos,i); XH"+oW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '4[=*!hs!  
fileSplitterFetch.start(); G^~[|a4`  
} vxOqo)yO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z1PwupXt1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9CY{}g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !Rn6x $_  
nEndPos = " + nFileLength); _rT\?//B  
// fileSplitterFetch[nPos.length-1].start(); ,^UqE{  
|h>PUt@LL  
h:YD$XE  
//等待子线程结束 ;]>kp^C#  
//int count = 0; L*(9Hti  
//是否结束while循环 <'a~Y3B"o  
boolean breakWhile = false; ~t`^|cr|  
Dcl$?  
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while(!bStop) eqo0{e  
{ Z!1D4`w  
write_nPos(); MtLWpi u@[  
Utility.sleep(500); J D\tt-  
breakWhile = true; kQ`tY`3F  
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for(int i=0;i<nStartPos.length;i++) PsY![CPrW  
{ 2Je$SE8  
if(!fileSplitterFetch.bDownOver) e w^(3&  
{ r
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breakWhile = false; `ONjEl  
break; x84!/n^z  
} :xh{SsW@  
} \Pg~j\;F]  
if(breakWhile) 37#&:[w>  
break; D*XrK0#Z`  
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{i5?R,a)  
//count++; PobX;Z  
//if(count>4) }u Y2-l  
// siteStop(); bjZJP\6  
} F^i3e31*t  
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System.err.println("文件下载结束！"); jh5QIZf=  
} |.<_$[v[x  
catch(Exception e){e.printStackTrace ();} `KJ(.m  
} ,
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//获得文件长度 wwUI ;g  
public long getFileSize() #NS|9jW  
{ -;""l{  
int nFileLength = -1; zp:dArh0  
try{ 0YH5B5b  
URL url = new URL(siteInfoBean.getSSiteURL()); l=@ B 'a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =%Y1]F  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ltlp9 S  
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XJ18(Q|w'  
int responseCode=httpConnection.getResponseCode(); @CprC]X  
if(responseCode>=400) -<W?it?D  
{ *t@A-Sn  
processErrorCode(responseCode); ]a $6QS  
return -2; //-2 represent access is error du65=w4E!  
} AIF?>wgq  
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String sHeader; C{exvLQ  
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for(int i=1;;i++) 8 Rx@_  
{ *PJH&
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A*JOp8\)  
//Utility.log(in.readLine()); B8&q$QV  
sHeader=httpConnection.getHeaderFieldKey(i); Z,&O8Jelf  
if(sHeader!=null) +m=b "g  
{ u3T-U_:jSV  
if(sHeader.equals("Content-Length")) cslC+e/  
{ 727#7Bo  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); crmQn ^4\  
break; Cxf K(F  
} E`HoJhB  
} b<h((]Q>^  
else "?" :  
break; }:m#}s  
} Mz@{_*2   
} 7?.uAiM'zT  
catch(IOException e){e.printStackTrace ();} <)qa{,GX\  
catch(Exception e){e.printStackTrace ();} =RoE=)1&-  
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Utility.log(nFileLength); xUJ(tG3  
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return nFileLength; K\xz|Gq  
} \!ZA#7  
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//保存下载信息（文件指针位置） b
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private void write_nPos() Q2CGC+   
{ " ityx?  
try{ g
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output = new DataOutputStream(new FileOutputStream(tmpFile)); kQ\GVI11?  
output.writeInt(nStartPos.length); #2=l\y-#  
for(int i=0;i<nStartPos.length;i++) 9Po>laT 5  
{ q<}IO  
// output.writeLong(nPos); Agd"m4!  
output.writeLong(fileSplitterFetch.nStartPos); ,xwiJfG; ]  
output.writeLong(fileSplitterFetch.nEndPos); FPc`J  
} u#6s^ )W  
output.close(); |W@ ~mrO  
} xQR/Xp!h  
catch(IOException e){e.printStackTrace ();} /_{-~0Z=@B  
catch(Exception e){e.printStackTrace ();} ju2H0AQ  
} &r,vD,  
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//读取保存的下载信息（文件指针位置） 7mt
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private void read_nPos() d=1\=d/K  
{ 73q
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try{ Csyh 'v  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %YVPm*J~  
int nCount = input.readInt(); g0
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nStartPos = new long[nCount]; .7.G}z1  
nEndPos = new long[nCount]; G}U <^]c  
for(int i=0;i<nStartPos.length;i++) ^"Bhp:o2  
{ Q g/Rw4[  
nStartPos = input.readLong(); S{llpp{E  
nEndPos = input.readLong(); @5d^ C  
} 8Hq4
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input.close(); hy/g*>  
} bAlty}U  
catch(IOException e){e.printStackTrace ();} vhMoCLb  
catch(Exception e){e.printStackTrace ();} <v1H1'gv  
} 7a[6@  
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, S^y>  
private void processErrorCode(int nErrorCode) ?CCQm  
{ YM#'+wl}`  
System.err.println("Error Code : " + nErrorCode); o^@#pU <  
} x~k3kj  
{~&]  
23|JgKuA  
//停止文件下载 &q&z$Gc;m  
public void siteStop() ;FI'nL  
{ ,`U>BBBLv  
bStop = true; `;Ui6{|  
for(int i=0;i<nStartPos.length;i++) "IS; o o$g  
fileSplitterFetch.splitterStop(); xM{[~Kh_x  
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} sct3|H#  
} 75>%!
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//负责部分文件的抓取 ke@OG! M/  
**FileSplitterFetch.java EFi
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*/ 5X8 i=M;  
package NetFox; N9ipwr'P  
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import java.io.*; ,or;8aYc#  
import java.net.*; @Y,t]  
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public class FileSplitterFetch extends Thread { k %{q q v  
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String sURL; //File URL :bo2H[U+  
long nStartPos; //File Snippet Start Position f7zB_hVDmE  
long nEndPos; //File Snippet End Position Vh01y f  
int nThreadID; //Thread's ID bfUKh%!M  
boolean bDownOver = false; //Downing is over ,nog6\  
boolean bStop = false; //Stop identical )a!f")@uz  
FileAccessI fileAccessI = null; //File Access interface -~sW@u)O  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .`*(#9(M9  
{ m[l&&(+J,  
this.sURL = sURL; (gdzgLHy  
this.nStartPos = nStart; I 8 ?  
this.nEndPos = nEnd; )-XD= ]  
nThreadID = id; xn=mS!"1Zo  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]}S9KP  
} , iEGf-!k  
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public void run() sj+
)  
{ F)l1%FCm  
while(nStartPos < nEndPos && !bStop) u3cg&lEgT  
{ ~urk Uz  
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try{ 2#R0Bd  
URL url = new URL(sURL); EE9eG31|r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
@Rd`/S@  
httpConnection.setRequestProperty("User-Agent","NetFox"); u3X!O  
String sProperty = "bytes="+nStartPos+"-"; ;M+~e~  
httpConnection.setRequestProperty("RANGE",sProperty); #pD=TMefC  
Utility.log(sProperty); [MAvU?;  
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InputStream input = httpConnection.getInputStream(); t,5AoK/NL9  
//logResponseHead(httpConnection); BgsU:eKe  
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byte[] b = new byte[1024]; ypvz&SzIh  
int nRead; {o%OG/!1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L>`inrpz=w  
{ tac_MtW?  
nStartPos += fileAccessI.write(b,0,nRead); {ZUgyGE{  
//if(nThreadID == 1) _:XX+3W7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /7R0w  
} :Q;mgHTNz  
n}J!?zZc  
A2nL=9~   
Utility.log("Thread " + nThreadID + " is over!"); ocj^mxh=O  
bDownOver = true; ZjgfkZAS  
//nPos = fileAccessI.write (b,0,nRead); ?KFj=Yo  
} ~kZ?e1H  
catch(Exception e){e.printStackTrace ();} cw;TIx_q  
} g0s*4E  
} wEix8Ow*  
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5Kkp1K$M  
//打印回应的头信息 i7O8f^|  
public void logResponseHead(HttpURLConnection con) dJ7!je1N*  
{ Hy2~D:34  
for(int i=1;;i++) ]L!:/k,=S  
{ (+9^)No  
String header=con.getHeaderFieldKey(i); j'LO'&sQ(  
if(header!=null) ghaO#kI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); KD8,a+GL  
Utility.log(header+" : "+con.getHeaderField(header)); 8sU}[HH*1  
else $_u)~O4$  
break; 7eyx cr;z  
} "tU,.U
 
} kIH)>euZ  
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public void splitterStop() F t;[>o  
{ &}b-aAt  
bStop = true; NfXEW-  
} O.'\GM  
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} Eh.NJI(  
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-<@QR8:  
/*  kSU]~x  
**FileAccess.java  pytF K)U  
*//文件访问(定位，写) %gV~e@|  
package NetFox; 4w(#`'I>  
import java.io.*; [UYE.$Y#(  
\t%rIr  
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public class FileAccessI implements Serializable{ {Nny.@P)H  
= ^_4u%}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fV5MI[t  
RandomAccessFile oSavedFile; ^Z:qlYZ  
long nPos; vFl06N2  
"/$2oYNy+  
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public FileAccessI() throws IOException Ce!xa\  
{ q;=!=aRg  
this("",0);
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} /zZ";4  
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public FileAccessI(String sName,long nPos) throws IOException MtKM#@  
{ rJ)8KY>  
oSavedFile = new RandomAccessFile(sName,"rw"); aXRf6:\%  
this.nPos = nPos; I/ V`@*/+  
oSavedFile.seek(nPos); xdkC>o4>  
} *^Xtorqo  
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public synchronized int write(byte[] b,int nStart,int nLen) TIYo&?Z)  
{ |.Vs
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int n = -1; P&}J(;Lbl  
try{ v2;'F  
oSavedFile.write(b,nStart,nLen); $hq'9}ASOL  
n = nLen; ~3,k8C"pRq  
} w  
catch(IOException e) t?;\'  
{ nX|]JW  
e.printStackTrace (); &$8YW]1M  
} {?hpW+1,#  
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return n; G%5ZG$as  
} A8U\/GP  
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} xnvG5  
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T3,}CK#O  
/* U2vM|7]VP  
**SiteInfoBean.java @M&qH[tK-A  
*/ i.Z iLDs\7  
package NetFox; Y4Y~ep  
S:8 WBY]M  
X<mlaXwrA  
public class SiteInfoBean { gi #dSd1\&  
o9]i {e>L  
)];Bo.QA  
private String sSiteURL; //Site's URL H7dT6`<~Y  
private String sFilePath; //Saved File's Path _bn "c@s  
private String sFileName; //Saved File's Name Z~1uyr(  
private int nSplitter; //Count of Splited Downloading File 0,5)L\{ R  
7(l>Ck3B#  
Nk;ywC"e;  
public SiteInfoBean() hMnm>  
{//nSplitter的缺省值为5 Wn-'iD+9<  
//default value of nSplitter is 5 DPr~DO`b  
this("","","",5); H*HL:o-[  
} ;(&S1Rv9  
#7['M;_  
J#xZ.6)  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u~7fK  
{ 7j8lhrM}^  
sSiteURL= sURL; 6u>]-K5  
sFilePath = sPath; ?&?5x%|.<  
sFileName = sName; )kDB*(?  
this.nSplitter = nSpiltter; <b:xyHS  
j]C}S*`"  
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} L%jIU<?Z7  
 0*E_D  
8]D0)  
public String getSSiteURL() :!Nx'F9a  
{ //'&a-%$^  
return sSiteURL; ohjl*dw
 
} 8([ MR  
$0k7W?tu  
u+^KP>rM(  
public void setSSiteURL(String value) &0i$Y\g  
{ }bSDhMV;  
sSiteURL = value; N\|BaZ%>|  
} q@g#DP+C  
\)?+6D'#  
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public String getSFilePath() =R
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{ =3ovaP  
return sFilePath; 1R;@v3  
} N0%q66]1  
_xmQGX!|  
*?\u5O(  
public void setSFilePath(String value) mx#%oJnsi  
{ E*h!{)z@F  
sFilePath = value; {,u})U2  
} Kv2S&P|jXM  
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public String getSFileName() g/_0WW]}  
{ *AP"[W  
return sFileName; JEaTDV_  
} T@*'}*  
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no W]E}nN  
public void setSFileName(String value) \Z,{De%  
{ w$Fg0JS  
sFileName = value; 8*x=Fm,Ok  
} _9JFlBx  
.xuzu#-  
8\^A;5  
public int getNSplitter() lZuH:AH  
{ iEZ+Znon  
return nSplitter; DIw_"$'At  
} EZN!3y|m  
46pR!k  
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public void setNSplitter(int nCount) vzFpXdt  
{ s'
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nSplitter = nCount; i#hFpZ6u  
} g&85L$   
} amdgb,vh  
7KX27.~F  
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/* D%nd7 |  
**Utility.java jeJgDAUv  
*/ /KX+'@  
package NetFox; \0d'y#Gp*  
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public class Utility { a!E22k?((z  
p/?o^_s  
eF22 ~P  
public Utility() $q)YC.5$  
{ %ACW"2#(  
a \1QnCy  
{V2"Pym?  
} P+}~6}wJE  
MCmb/.&wu  
//线程睡眠 7!pKlmQ  
public static void sleep(int nSecond) .Mb[j1L^  
{ uW(-?  
try{ 8ROKfPj;z  
Thread.sleep(nSecond); {9U!0h-2"  
} BZ?Ck[E]Z  
catch(Exception e) ERV]N:(  
{ 3X`9&0:j%  
e.printStackTrace (); eMC^ORdY  
} Mh
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} d"9tP& Q  
<.QaOLD  
//日志 &,k!,<IF  
public static void log(String sMsg) J8alqs7  
{ j)mU`b_  
System.err.println(sMsg); \D?'.Wo%  
} ORs:S$Nt$  
-[L\:'Gp5  
sv%X8  
public static void log(int sMsg) pT]hPuC  
{ T+}|$/Tv  
System.err.println(sMsg); #ODP+>-IjB  
} \5r^D|Rp}  
} ]`&_!T  
6DHK&<=D8  
$v;WmYTJ  
/* Xfq`k/ W  
**TestMethod.java lPR=C0h}@  
*/ \%a0Lp{ I  
package NetFox; :2?g_  
lFBpNUnzU  
;'n%\*+fHH  
public class TestMethod { t{]Ew4Y4%O  
c4tw)O-X  
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public TestMethod() mAW.p=;  
{ ///xx/weblogic60b2_win.exe %GhI0F #  
try{ P8z%*/ 3NF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "]S  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); d+q],\"R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .Fo#Dmq3  
fileFetch.start(); 5qz,FKx5  
} BPO5=]W 7  
catch(Exception e){e.printStackTrace ();} <L-F3Buu  
H9*k(lnz`  
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} a2Ak?W1  
}4|EHhG  
L kK *.  
public static void main(String[] args) $tmdE)"&  
{ '=_(fa,  
new TestMethod(); LiG$M{0  
} >yC=@Uq+  
} Jl{ 0q7b  
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