http断点续传简单实现（java)

/* {BKr/) H  
**SiteFileFetch.java Q!dNJQpb  
*/ K# dV.  
package NetFox; f; 1C)  
import java.io.*; 7lz"^  
import java.net.*; :X;AmLf`2u  
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public class SiteFileFetch extends Thread { oZ(T`5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean `Dco!ih  
long[] nStartPos; //开始位置 *m[ow s  
long[] nEndPos; //结束位置 e.IKmH]z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =K2mR}n\;  
long nFileLength; //文件长度 D*R49hja{  
boolean bFirst = true; //是否第一次取文件 tgbr/eCoU  
boolean bStop = false; //停止标志 ^J=l]  l  
File tmpFile; //文件下载的临时信息 xPi/nWl`|  
DataOutputStream output; //输出到文件的输出流 `?ijKZ}y5  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） X4R+Frt8  
public SiteFileFetch(SiteInfoBean bean) throws IOException }6Uw4D61  
{ p7;/| ]o3  
siteInfoBean = bean; Ih.6"ISK}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &zYo   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2nRL;[L*.  
if(tmpFile.exists ()) E5<}7Pt  
{ VfiMR%i}  
bFirst = false; NN9`jP2  
read_nPos(); H `V3oS~}  
} (fjAsbT  
else ]7, mo  
{ /8SQmh$+e  
nStartPos = new long[bean.getNSplitter()]; 6*<=(SQI  
nEndPos = new long[bean.getNSplitter()]; nVC:5ie  
} 1wa zJj=v  
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} bt,^-gt@  
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public void run() 6"Km E}  
{ *8uSy/l  
//获得文件长度 btK| U  
//分割文件 l*|^mx^Q  
//实例FileSplitterFetch Dm j^aFB0|  
//启动FileSplitterFetch线程 ?
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//等待子线程返回 pH%cbBm  
try{ T7AFL=  
if(bFirst) lMX 2O2 o  
{ AFWcTz6#d  
nFileLength = getFileSize(); bN$!G9I!,  
if(nFileLength == -1) xP.B,1\X  
{ u":D{+wC|  
System.err.println("File Length is not known!"); eiJO;%fl>l  
} *=1;HN3  
else if(nFileLength == -2) \guZc}V]:\  
{ U
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System.err.println("File is not access!"); oQC*d}_E}  
} "msCiqF{z  
else .#
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{ ${#5$U+kI  
for(int i=0;i<nStartPos.length;i++) ,P ?TYk  
{ *hAeA+:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :z^ps0  
} ]],6Fi+  
for(int i=0;i<nEndPos.length-1;i++) UAT46  
{ I?v)>||Q  
nEndPos = nStartPos[i+1]; aW7{T6
.,  
} aC>r5b#:  
nEndPos[nEndPos.length-1] = nFileLength; cve(pkl  
} $V~r*#$.  
} e_+`%A+-  
4:8#&eF  
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//启动子线程 WIXzxI<)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y6'Fi(2yw  
for(int i=0;i<nStartPos.length;i++) H*3f8A&@s  
{ ,~FyC_%*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5+GW%U/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h)q:nlKUW  
nStartPos,nEndPos,i); PG9won5_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !%NxSJ  
fileSplitterFetch.start(); PGMu6$  
} 7Nc@7_=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x{u_kepv[k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [kzcsJ'/e  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $nQ; ++  
nEndPos = " + nFileLength); Q{!l
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// fileSplitterFetch[nPos.length-1].start();  M}}9  
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{o7ibw=E)  
//等待子线程结束 ^aDos9SyV  
//int count = 0; gLQWL}0O  
//是否结束while循环 "uCx.Q9ef  
boolean breakWhile = false; T1;yw1/m5\  
]y$D@/L@  
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while(!bStop) 71cc6T  
{ ?]f+)tCMs  
write_nPos(); (o{-1Dg)  
Utility.sleep(500); F8YD:   
breakWhile = true; uJMF\G=nb  
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for(int i=0;i<nStartPos.length;i++) Z?[;Japg  
{ "j3Yu4_ks  
if(!fileSplitterFetch.bDownOver) |Wj)kr !|  
{ F {]:  
breakWhile = false; @y->4`N  
break; q^Lj)zmnK  
} ^o"9f1s5  
} P6S^wjk  
if(breakWhile) 8nQlmWpJ  
break; a9"x_IVU  
OnF+  
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//count++; oScHmGFv  
//if(count>4) iBxCk^  
// siteStop(); eGvHU ;@  
} :q;vZ6Xd  
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System.err.println("文件下载结束！"); q NU\XO`H  
} 88d0`6K-9  
catch(Exception e){e.printStackTrace ();} 17H_>a
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} O~9 %!LAu  
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//获得文件长度 <|Bh;;  
public long getFileSize()
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{ "f~S3?^!2  
int nFileLength = -1; i+Px &9o<9  
try{ w@nN3U+  
URL url = new URL(siteInfoBean.getSSiteURL()); ;Y j_@=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :doP66["!  
httpConnection.setRequestProperty("User-Agent","NetFox"); =iRc&  
0^]E-Zf  
7&:gvhw  
int responseCode=httpConnection.getResponseCode(); U[c,cdA  
if(responseCode>=400) 9/{+,RpC  
{ @;fdf3ian  
processErrorCode(responseCode); <QugV3e  
return -2; //-2 represent access is error Ngu+V  
} QSAz:Yvf|  
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String sHeader; G|'DAj%  
'-4);:(^  
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for(int i=1;;i++) JQ%e'  
{ 6t*pV [  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -/B}XNW  
//Utility.log(in.readLine()); CP|N
2rb  
sHeader=httpConnection.getHeaderFieldKey(i); "\vEi &C  
if(sHeader!=null) $[VKM|Zjw  
{ I(s\ Q[  
if(sHeader.equals("Content-Length")) c|:H/Y2n|  
{ MH?|>6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); PD$ay^Y  
break; :'f#0ox  
} aa.EtKl  
} l\ts!p4f$  
else hp%|n:.G  
break; 4M6o+WV  
} Q68&CO(rE  
} P_
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catch(IOException e){e.printStackTrace ();} zW!3>(L/  
catch(Exception e){e.printStackTrace ();} 3 {\b/NL$  
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Utility.log(nFileLength); %^p1ax  
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return nFileLength; ?<#6=  
} rfkk3oy  
ch 4z{7   
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//保存下载信息（文件指针位置） $s/N;E!t  
private void write_nPos() 9-Ikd>9  
{ tt{,f1v0t  
try{ .2C}8GGC'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gvr"F  
output.writeInt(nStartPos.length); +%7yJmMw  
for(int i=0;i<nStartPos.length;i++) a/NmM
)  
{ 9 @!Og(l  
// output.writeLong(nPos); DFwkd/3"  
output.writeLong(fileSplitterFetch.nStartPos); (NFq/w%  
output.writeLong(fileSplitterFetch.nEndPos); ^a[7qX_B  
} gkI(B2,/  
output.close(); a^~T-;_V  
} n (C*LK  
catch(IOException e){e.printStackTrace ();} XK`>#*"V  
catch(Exception e){e.printStackTrace ();} [k
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} 8ysU.5S  
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(Vf&,b@U_  
//读取保存的下载信息（文件指针位置） YKJk)%;+w  
private void read_nPos() |<\o%89AM  
{ _;O$ot\5  
try{ pT>[w1Kk^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); al F*L  
int nCount = input.readInt(); N0O8to}V  
nStartPos = new long[nCount]; "w*VyD  
nEndPos = new long[nCount]; 1tDd4r?Y  
for(int i=0;i<nStartPos.length;i++) 7 }4T)k(a  
{ .</d$FM JE  
nStartPos = input.readLong(); I+kGEHO}  
nEndPos = input.readLong(); O"<D0xzF?  
} )TP1i  
input.close(); lE78Yl]  
} /+1+6MqRn*  
catch(IOException e){e.printStackTrace ();} EFW'D=&h8  
catch(Exception e){e.printStackTrace ();} 5n"b$hMF  
} "9!ln  
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private void processErrorCode(int nErrorCode) X~*1  
{ u> XCE|D*  
System.err.println("Error Code : " + nErrorCode);  \U(qv(T  
} F-R4S^eV  
ZN~:^,PO/  
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//停止文件下载 Ck%nNy29  
public void siteStop() 3 q^3znt  
{ ^ b{0|:  
bStop = true; J(ZYoJ  
for(int i=0;i<nStartPos.length;i++) &p8b4y_  
fileSplitterFetch.splitterStop(); -M2c8P:.b  
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} TppR \[4]  
} n2zJ'  
//负责部分文件的抓取 26B]b{Iz{  
**FileSplitterFetch.java q(p]6Ha|  
*/ ]R32dI8N  
package NetFox; "-C.gqoB  
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import java.io.*; l ~CYxO  
import java.net.*; Qh<_/X?  
}dQW-U  
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public class FileSplitterFetch extends Thread { rz+)z:u  
cK%Sty'8+  
"#\\p~D/<  
String sURL; //File URL %ZF47P%6  
long nStartPos; //File Snippet Start Position Au<NUc 2  
long nEndPos; //File Snippet End Position a'u:1C^\  
int nThreadID; //Thread's ID lK;|ciq"c7  
boolean bDownOver = false; //Downing is over ~,3+]ts='\  
boolean bStop = false; //Stop identical *`&4<>=n  
FileAccessI fileAccessI = null; //File Access interface %$}aWzQxll  
'=C)Hj[D  
 G`8i{3:  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >Vc;s!R  
{ *WdnP.'Y  
this.sURL = sURL; Y` t-Bg!~  
this.nStartPos = nStart; ~3bH2,{L[  
this.nEndPos = nEnd; Kq&b1x  
nThreadID = id; ^h #0e:7<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 x8
:  
} 8-]\C  
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public void run() !o+[L  
{ 'b(V8x  
while(nStartPos < nEndPos && !bStop) 3"afrA  
{ Ot,eAiaX  
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>F7v'-*{  
try{ vt8z=O  
URL url = new URL(sURL); h2~b%|Pv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #$k6OlK-r"  
httpConnection.setRequestProperty("User-Agent","NetFox"); $}_a`~u  
String sProperty = "bytes="+nStartPos+"-"; qcpAjjK  
httpConnection.setRequestProperty("RANGE",sProperty); JR
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Utility.log(sProperty); c*R?eLt/  
3>O=d>  
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InputStream input = httpConnection.getInputStream(); BhFyEY(  
//logResponseHead(httpConnection); 5}-e9U  
~d5f]6#`  
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byte[] b = new byte[1024]; Igb@aGA  
int nRead; 2x3%*r$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '1rHvz`B/"  
{ Y243mq-  
nStartPos += fileAccessI.write(b,0,nRead); L{)*evBL  
//if(nThreadID == 1) R/5@*mv{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P:Nj;Cxh  
} Y9^;TQ+#  
xn1=@0 a  
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Utility.log("Thread " + nThreadID + " is over!"); En&`m  
bDownOver = true; N5m+r.<;  
//nPos = fileAccessI.write (b,0,nRead); x,LQA0  
} 0=g~ozEW&  
catch(Exception e){e.printStackTrace ();} 67,@*cK3?J  
} FH Hi/yh  
} (c3%rM m]  
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tZ4Zj`x|^  
//打印回应的头信息 Wbra*LNU  
public void logResponseHead(HttpURLConnection con) bIs@CDB  
{ RxUABF8b  
for(int i=1;;i++) *.g@6IkAQ  
{ dJ/(u&N  
String header=con.getHeaderFieldKey(i); BZUA/;Hz &  
if(header!=null) ~r%>x  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); HzuB.B<  
Utility.log(header+" : "+con.getHeaderField(header)); ItLP&S=  
else LA\)B"{J  
break; .LQvjK[N
 
} @ckOLtxE>  
} @)h
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public void splitterStop() fQ.{sQ$@h  
{ |~V`Es +j  
bStop = true; aNcuT,=(?8  
} estDW1i)  
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} w26x)(7  
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/* E]opA$JQ  
**FileAccess.java ;8VvpO^G/  
*//文件访问(定位，写) PR{y84$  
package NetFox; (K"8kQLY  
import java.io.*; =5zx]N1r  
6X1_NbC  
9gS.G2  
public class FileAccessI implements Serializable{ B^{87YR  
+0)zB;~7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F~qiNV  
RandomAccessFile oSavedFile; (";{@a %  
long nPos; `%a+LU2  
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public FileAccessI() throws IOException 'J0Erk8(  
{ ,:G3Y )  
this("",0); E\ 'X|/$a  
} ab5uZ0@  
_jhdqON6E  
Vv]81y15Q;  
public FileAccessI(String sName,long nPos) throws IOException vWM'}(  
{ [+j39d.Q  
oSavedFile = new RandomAccessFile(sName,"rw"); pbM"tr_A{  
this.nPos = nPos; c[a1
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oSavedFile.seek(nPos); *,Mg  
} Xy;!Q`h(  
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public synchronized int write(byte[] b,int nStart,int nLen) @Z50S 8  
{ s</llJ$  
int n = -1; .W9/*cZV0  
try{ !edgziuO  
oSavedFile.write(b,nStart,nLen); 4Pm
+0=E
 
n = nLen; x:Nd>Fb  
} UdS
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catch(IOException e) C}~/(;1V=  
{ Rlq6I?S+  
e.printStackTrace (); 7+h*&f3>  
} wn$:L9"YN  
4-YXXi}  
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return n; uy,ySBY  
} A{7N#-h_  
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} ElEa*70~g  
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v{H3DgyG  
/* O>![IH(L  
**SiteInfoBean.java 0M?nXHA[  
*/ vG
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package NetFox; rLzYkZ  
;[_w&"[6a  
)~](qLSl  
public class SiteInfoBean { ^1%gQ@P  
M?UlC   
OoFQ@zE7%  
private String sSiteURL; //Site's URL 1qs~[7{C1  
private String sFilePath; //Saved File's Path $=97M.E  
private String sFileName; //Saved File's Name E"[^^<I  
private int nSplitter; //Count of Splited Downloading File Wv  
[|sKu#yW  
mQ9%[U,  
public SiteInfoBean() \E'Nk$V3  
{//nSplitter的缺省值为5 D4"](RXH  
//default value of nSplitter is 5 h=3156M  
this("","","",5); WAj26";M(  
} {,5=U@J  
}}GBCXAf_  
,H3C\.%w\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .2xp.i{  
{ !n`ogzOh  
sSiteURL= sURL; =f)S=0UF  
sFilePath = sPath; VesO/xG<  
sFileName = sName; o3;u*f0rWn  
this.nSplitter = nSpiltter; X-Sso9/q.  
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} NRS!Ox  
@"~Mglgw  
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public String getSSiteURL() 7eh|5e$@  
{ mf26A
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return sSiteURL; y>S.B/d  
} F_SkS?dB  
tVhY=X{N?  
OpwZTy}1}  
public void setSSiteURL(String value) I +,D,Vg  
{ S?{|qlpy  
sSiteURL = value;
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} ,i2%FW  
|Hbe]2"x>  
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public String getSFilePath() Ii?"`d+JA  
{ .P=uR8  
return sFilePath; ou44vKzS  
} Z_qs_/y  
b; SFnZa8  
r +] J {k  
public void setSFilePath(String value) @o+T<}kWX  
{ SnbH`\U"  
sFilePath = value; (k"oV>a|  
} N(?yOB4gt  
%iI0JF*Ez  
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public String getSFileName() N0c+V["s  
{ `8F%bc54iw  
return sFileName; ZkYc9!anY  
} >GiM?*cC  
{uO8VL5+Qx  
9p!V?cH#8  
public void setSFileName(String value) n=RAE^[
M  
{ k=[!{I  
sFileName = value; Z'GOp?  
} /UjRuUC]  
NQ<~$+{  
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public int getNSplitter() *DX6m  
{ Y*``C):K%  
return nSplitter; wLD/#Hfi7  
} ~(B\X?v  
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2 G_*Pqc  
public void setNSplitter(int nCount) a#1LGH7E8  
{ ewgcpV|spn  
nSplitter = nCount; vi0% jsI  
} K0]'v>AWr  
} w\;=3C`  
?ZSG4La\  
v,RLN`CID  
/* 2 c'=^0:  
**Utility.java @yaBtZUp3  
*/ +by
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package NetFox; !23W=N}82  
}i/&m&VU  
"zw?AC6  
public class Utility { Ul[>LKFY  
p;j$i6YJ  
0|{U"\  
public Utility() ]t1)8v2w>  
{ `q eL$`  
W.\HfJ74  
i#1T68y}  
} Qd!;CoOmZs  
44?5]C7  
//线程睡眠 6!bA~"N  
public static void sleep(int nSecond) (k M\R|  
{ Xr M[8a  
try{ KLqu[{y.'  
Thread.sleep(nSecond); ;sNyN#  
} iTD}gC  
catch(Exception e) P1 (8foZA  
{ > Q@*o  
e.printStackTrace (); (eJr-xZ/  
} $t1]w]}d  
} dqUhp_f2qK  
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//日志 U3lr<(r*  
public static void log(String sMsg) |i?AtOt@f  
{ p`1d'n[  
System.err.println(sMsg); X>%2\S  
} {L$b$u$7:  
W\U zw,vI  
-ihF)^"a  
public static void log(int sMsg) }#<Sq57n  
{ ;y6Jo  
System.err.println(sMsg); 5v
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} >o 3X)  
} 1y0.tdI(  
2I?HBz1v  
j#&sZ$HQ4  
/* 4>Uo0NfL  
**TestMethod.java l(=#c
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*/ ]vQo^nOo  
package NetFox; PBn(k>=+  
(fh:q2E#  
NFLmM  
public class TestMethod { UUb!2sO  
$'9r=#EH  
DGHX:Ft#  
public TestMethod() 83i%3[L  
{ ///xx/weblogic60b2_win.exe gSR&CnqZ<  
try{ ~8pf.^,fi  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a4`@z:l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7R))(-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); bvG").8$  
fileFetch.start(); &
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} #yr19i ?  
catch(Exception e){e.printStackTrace ();} $o]zNW;X  
;S`Nq%,  
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} A$XjzTR  
nQ$N(2<Fe  
(m04Z2#  
public static void main(String[] args) mZ/B:)_  
{ 1LPfn(  
new TestMethod(); 'b661,+d  
} ?783LBe  
} hD>:WJ  
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