http断点续传简单实现（java)

/* O/9%"m:i  
**SiteFileFetch.java !lQ#sL`  
*/ .k# N7[q=  
package NetFox; 6}VUD -}B  
import java.io.*; 0Jm]f/iZ  
import java.net.*; CS~=Z>6EjA  
[c&2i`C  
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public class SiteFileFetch extends Thread { k~0#'I
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SiteInfoBean siteInfoBean = null; //文件信息Bean *'Z-OY<V  
long[] nStartPos; //开始位置 lZ}izl  
long[] nEndPos; //结束位置 (b
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 w) =eMdj\o  
long nFileLength; //文件长度 ixOEdQ  
boolean bFirst = true; //是否第一次取文件 r#LnDseW  
boolean bStop = false; //停止标志 >$2E1HW.  
File tmpFile; //文件下载的临时信息 =y?#^  
DataOutputStream output; //输出到文件的输出流 'n~fR]
h}  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3H1Pp*PH  
public SiteFileFetch(SiteInfoBean bean) throws IOException  qovQ9O  
{ 4Z*|Dsw  
siteInfoBean = bean; OZ
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y&7YJx  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pp(H PKs=}  
if(tmpFile.exists ()) FI\IY R  
{ 2bWUa~%B  
bFirst = false; hO#HvW  
read_nPos(); &kb\,mQ  
} #-,g&)`]  
else d{W}p~UbH  
{ >W'j9+Va  
nStartPos = new long[bean.getNSplitter()]; d&hD[v  
nEndPos = new long[bean.getNSplitter()]; y $:yz;  
} ~NxEc8Y  
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} Z)NrhJC  
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public void run() |B eA
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{ \
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//获得文件长度 r]9e^  
//分割文件  *.8JP  
//实例FileSplitterFetch eO'xkm  
//启动FileSplitterFetch线程 d4
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//等待子线程返回 i(0hvV>'  
try{ 2\5cjdy  
if(bFirst) Ss 2$n  
{ r ^MiRa  
nFileLength = getFileSize(); >&1um5K  
if(nFileLength == -1) x:qr\Rz  
{ Pw= 3PvkL  
System.err.println("File Length is not known!"); SBX|Bcyk*  
} }C_
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else if(nFileLength == -2) LP,9<&"<  
{ O] H=s  
System.err.println("File is not access!"); @HvScg*Y  
} rCE;'? Y  
else .liyC~YW  
{ WO
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for(int i=0;i<nStartPos.length;i++) !y%+GwoW  
{ ;b1wk^,Hw~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JR)/c6
j  
} 8)Zk24:])_  
for(int i=0;i<nEndPos.length-1;i++) XCm\z9F  
{ F@1d%c  
nEndPos = nStartPos[i+1]; /VO^5Dnb  
} LEK/mCL  
nEndPos[nEndPos.length-1] = nFileLength; U@?6*,b(.  
} qOi5WX6F/  
} &n|*uLn  
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's.~$  
//启动子线程 `L\)ahM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _88QgThb  
for(int i=0;i<nStartPos.length;i++) {5-zyE  
{ 4uUs7T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -\Z `z}D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jTfi@5aPY  
nStartPos,nEndPos,i); HIGNRm  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0[)VO[  
fileSplitterFetch.start(); x@m<Ym-  
} E:w:4[neh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *,lh:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); VNj@5s  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sofu  
nEndPos = " + nFileLength); Yj|]Uff8O  
// fileSplitterFetch[nPos.length-1].start(); /C$ xH@bb  
K%gP5>y*9>  
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//等待子线程结束 V7C1FV2  
//int count = 0; %hINpZMr  
//是否结束while循环 Jq .L:>x  
boolean breakWhile = false; j[XYj6*d  
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while(!bStop) RtC'v";6  
{ +.@c{5J<  
write_nPos(); bRPO:lAy  
Utility.sleep(500); @B`Md3$7
 
breakWhile = true; tg
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for(int i=0;i<nStartPos.length;i++) }Hy ~i  
{ jPk c3dG +  
if(!fileSplitterFetch.bDownOver) DMZ`Sx  
{ mp\%M 1<  
breakWhile = false; >]&X ^V%Q#  
break; ll<mE,  
} Ld(NhB'7  
} )acV-+{  
if(breakWhile) jGD%r~lN  
break; SRL-Z&M  
V1utUGJV  
Bo r7]#  
//count++; #?&0D>E?k  
//if(count>4) #3MKH8k&~  
// siteStop(); 'Kz9ygZy  
} !/
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q`Q}yE>9  
)q3"t2-  
System.err.println("文件下载结束！"); k^An97J  
} E5UcZ
7  
catch(Exception e){e.printStackTrace ();} Gt~JA0+C)7  
} s@!$='|  
R1%y]]*-P  
*YvRNHP  
//获得文件长度 ,W*H6fw+  
public long getFileSize() ({[,$dEa;  
{ S_Z`so}  
int nFileLength = -1; {gU&%j  
try{ ZK!A#Jm{  
URL url = new URL(siteInfoBean.getSSiteURL()); 6E^~n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MYdx .NZT  
httpConnection.setRequestProperty("User-Agent","NetFox"); &mkpJF/  
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h-mTj3p-K  
int responseCode=httpConnection.getResponseCode(); 97LpY_sU  
if(responseCode>=400) PW)aLycPK  
{ ngUHkpYS5  
processErrorCode(responseCode); *%A}x   
return -2; //-2 represent access is error |4C^$  
} :
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P(ZQDTbM :  
String sHeader; PC/!9s0W  
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for(int i=1;;i++) &u8z5pls8  
{ geGeZ5+B  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /[pqI0sf<A  
//Utility.log(in.readLine()); U^_D|$6  
sHeader=httpConnection.getHeaderFieldKey(i); lLiQ;@  
if(sHeader!=null) eOY^$#Y  
{ wda';@y5(  
if(sHeader.equals("Content-Length")) LmLGki$w  
{ ];FtS>\x  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m*n5zi|O  
break; g9>~HF$U  
} -%m3-xZA  
} wNDbHR  
else Eipp~GD  
break; nhH;?D3  
} qX6D1X1_  
} p'Bm8=AwD  
catch(IOException e){e.printStackTrace ();} k<Sl1vK  
catch(Exception e){e.printStackTrace ();} (Hp'B))2  
yyP-=Lhmo=  
\b8\Ug~t  
Utility.log(nFileLength); 1r9f[j~  
..qd,9H  
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return nFileLength; $G!R,eQ  
} ]<trA$ 0  

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//保存下载信息（文件指针位置） aMwB>bt  
private void write_nPos() Vfs$VY2.  
{ <bUe/m  
try{ :T@r*7hNT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (03pJV&K  
output.writeInt(nStartPos.length); Mr3-q  
for(int i=0;i<nStartPos.length;i++) qx)?buAij  
{ %&+59vq   
// output.writeLong(nPos); b{cU<;G)y.  
output.writeLong(fileSplitterFetch.nStartPos); E^V|  
output.writeLong(fileSplitterFetch.nEndPos); k*Nr!Z!}  
} jAhP> t:  
output.close(); Y`ihi,s`H  
} gK1g]Tc@G  
catch(IOException e){e.printStackTrace ();} EbK0j?  
catch(Exception e){e.printStackTrace ();} )u} Q:`9  
} x\\7G^$<h  
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//读取保存的下载信息（文件指针位置） u=NG6
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private void read_nPos() T0QvnIaP  
{ F:g=i}7  
try{ E3l*8F%<3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Dd $qQ  
int nCount = input.readInt(); F jrINxL7^  
nStartPos = new long[nCount]; @F5f"8!.\  
nEndPos = new long[nCount]; x_<qzlQt  
for(int i=0;i<nStartPos.length;i++) i'HQQWd  
{ 4{na+M  
nStartPos = input.readLong(); dF@)M  
nEndPos = input.readLong(); L36Yx7gT<  
} -K%5(Eg  
input.close(); #bnb': f  
} Ol@_(U  
catch(IOException e){e.printStackTrace ();} 2W<n5o   
catch(Exception e){e.printStackTrace ();} blt'={Z?.x  
} ERMa# L  
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9<1F[SS<s9  
private void processErrorCode(int nErrorCode) 9U_ks[Qa  
{ E1V^}dn  
System.err.println("Error Code : " + nErrorCode); Qyh/ed/  
} d IB }_L  
~}9PuYaD@  
\Ad7 Gi~  
//停止文件下载 RYR-K^;R  
public void siteStop() V2d,ksKwn  
{ Fwg^(;bL  
bStop = true; 'S4)?Z  
for(int i=0;i<nStartPos.length;i++) :QQlI  
fileSplitterFetch.splitterStop(); '?5j[:QY@  
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L=!of{4Z(}  
} *|:Q%xr-  
} 7{kP}?  
//负责部分文件的抓取 uXZg1F)  
**FileSplitterFetch.java !kuX,*}q  
*/ q3e8#R)l  
package NetFox; :*i f  
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import java.io.*; ,I.WX,OR  
import java.net.*; a>m
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@J'YV{]  
%at
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2!  
public class FileSplitterFetch extends Thread { .)XP\m\  
?}p:J{  
Q\Kx"Y3i  
String sURL; //File URL u eb-2[=  
long nStartPos; //File Snippet Start Position vXj<  
long nEndPos; //File Snippet End Position <X7\z  
int nThreadID; //Thread's ID s Kicn5  
boolean bDownOver = false; //Downing is over dR^"X3$  
boolean bStop = false; //Stop identical %D}H|*IPu  
FileAccessI fileAccessI = null; //File Access interface E;Y;r"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException K{fsn4rk  
{ !BIOY!M  
this.sURL = sURL; Qeq5gN]  
this.nStartPos = nStart; ShOX<Fb&  
this.nEndPos = nEnd; eet Q}]  
nThreadID = id; C#pZw[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 RIn9(r  
} VR{+f7:}  
7Cqcb>\X  
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public void run() F/c$v  
{ Mj=$y?d ]  
while(nStartPos < nEndPos && !bStop) `Nh"  
{ eJCjJ)  
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sM[I4.A3  
try{ 13'vH]S$M  
URL url = new URL(sURL);
u6u=2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q^Ql
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httpConnection.setRequestProperty("User-Agent","NetFox"); V%0I%\0Y  
String sProperty = "bytes="+nStartPos+"-"; ykg#{9+  
httpConnection.setRequestProperty("RANGE",sProperty); /t<@"BoV  
Utility.log(sProperty); RkEN ,xWE  
2S3lsp5!  
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InputStream input = httpConnection.getInputStream();
5+Mdh`  
//logResponseHead(httpConnection); 3-n19[zk  
L)QE`24  
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byte[] b = new byte[1024]; lfsqC};#\  
int nRead; <|Yj%f  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0H_!Kg  
{ c?2MBtnu  
nStartPos += fileAccessI.write(b,0,nRead); Q:C$&-$  
//if(nThreadID == 1) :p&!RI(l  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qB]i6*  
} |WryBzZ>on  
nP~({:l8X  
;^Sr"v6r>u  
Utility.log("Thread " + nThreadID + " is over!"); !}+tdT(y  
bDownOver = true; -m= 8&B  
//nPos = fileAccessI.write (b,0,nRead); )
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} ^I6^g  
catch(Exception e){e.printStackTrace ();} c)md  
}  >YtdA  
} dBV7Te4L  
6pOx'u>h+  
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//打印回应的头信息 @XD+'{]  
public void logResponseHead(HttpURLConnection con) ^[-el=oKn0  
{ 5Ky#GuC  
for(int i=1;;i++) s#Jh -+lM  
{ ,vqr<H9e  
String header=con.getHeaderFieldKey(i); D'l5Zd  
if(header!=null) /y7M lU9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Xb !MaNm)  
Utility.log(header+" : "+con.getHeaderField(header)); {K{EOB_u  
else )?M9|u  
break; Ch()P.n?  
} b*fgv9Kh'  
} O|A_PyW  
aq+Y7IR_  
']-@?sD$  
public void splitterStop() '$As<LOEd/  
{ e7fiGl  
bStop = true; }ZSQ>8a  
} {wF&+kH3  
#eU.p&Zc  
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} Ko&hj XHx  
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/* *?+V65~dW  
**FileAccess.java =&0wr6  
*//文件访问(定位，写) B{oU,3U>  
package NetFox; YI-O{U  
import java.io.*; 2>-S-;i  
f"7M^1)h2%  
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public class FileAccessI implements Serializable{ V>64/  
:{'k@J"|a  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q1y/x@  
RandomAccessFile oSavedFile; biozZ  
long nPos; cH<q:OYi  
Ov-b:lH  
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public FileAccessI() throws IOException E$a ?LFa6  
{ B,z<%DAE  
this("",0); }7{t^>;D  
} k{tMzx]F__  
NVIK>cT6  
a</D_66  
public FileAccessI(String sName,long nPos) throws IOException VN4yn| f/  
{ zPEg  
oSavedFile = new RandomAccessFile(sName,"rw"); H9 C9P17  
this.nPos = nPos; 7z\m; 1  
oSavedFile.seek(nPos); jNwjK
0?  
} 41#w|L \  
#X: 'aj98  
UL
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public synchronized int write(byte[] b,int nStart,int nLen) b1pQ`qt  
{ 9/SXs0  
int n = -1; Lf:uNl*D  
try{ *O:r7_ Y0  
oSavedFile.write(b,nStart,nLen); rOW-0B+N  
n = nLen; $d+DDm1o  
} It_M@  
catch(IOException e) : FAH\  
{ /wQL  
e.printStackTrace (); 2c<&eX8"  
} rA0,`}8\  
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return n; e73^#O&Xt  
} v]2S`ffP  
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} qZ@0]"h  
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/* 6nDV1O5  
**SiteInfoBean.java c_{z(W"  
*/ AJt!!crs  
package NetFox; D/(L  
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public class SiteInfoBean { (-
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50jOA#l[  
private String sSiteURL; //Site's URL #Z=t
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private String sFilePath; //Saved File's Path 5_K5?N  
private String sFileName; //Saved File's Name hovGQHg  
private int nSplitter; //Count of Splited Downloading File lJykyyCY+  
MgnM,95  
c- $Gpa}M  
public SiteInfoBean() /4=-b_2Y~  
{//nSplitter的缺省值为5 9D
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//default value of nSplitter is 5 %kf>&b,Mi  
this("","","",5); \a"Ct
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} W!$zXwY}(  
vY6W|<s  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kg5ev8  
{ J}spiVM  
sSiteURL= sURL; 1F[L"W;r  
sFilePath = sPath; OL59e%X  
sFileName = sName; +H'\3^C-  
this.nSplitter = nSpiltter; hq_~^/
v\  
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} m@qqVRn#)  
/)#8)"`nT  
:X>DkRP  
public String getSSiteURL() D!FaEN  
{ us{nyil1  
return sSiteURL; =&U`9qN  
} u}jrfKdE  
+$pJ5+v  
*Zkss   
public void setSSiteURL(String value) \KM|f9-b  
{ :EHQ .^  
sSiteURL = value; _vrWj<wyf  
} mvTb~)  
uEd,rEB>  
R{3CW^1
  
public String getSFilePath() d'zT:g  
{ aWvd`qA9r  
return sFilePath; &hN,xpC  
} Fj=NiZ=  
:,F=w0O  
0=[0|`x  
public void setSFilePath(String value) $L{7%]7QC  
{ ,IjdO(?TC  
sFilePath = value; vjTwv+B"  
} :C%47qv  
\Hum}0[  
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public String getSFileName() S}gD,7@  
{ ,L%p
  
return sFileName; QkX@QQT?  
} {wu!6\:<??  
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r<(kLpOH%  
public void setSFileName(String value) oQvFrSz  
{ I7Zq}Pxa  
sFileName = value; *|'}v[{v^9  
} cEi<}9r  
9p<:LZd~  
Oxn'bh6R0  
public int getNSplitter() VRhRwdC  
{ LW?2}`+  
return nSplitter; -s~p}CQ.  
} ~~dfpW_"  
w:R]!e_6\9  
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public void setNSplitter(int nCount) `q1}6U/k  
{ ddMM74  
nSplitter = nCount; 4H9xO[iM  
} gT7I9 (x!W  
} D4\(:kF\Hg  
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d.1Q~&`  
/* Y;PDZbK3  
**Utility.java XAlD  ww  
*/ %>]#vQ|  
package NetFox; Faw. GU  
| &\^n2`>  
$YR{f[+L w  
public class Utility { pb=HVjW<  
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public Utility() "p2u+ 8?  
{ _4S7wOq5  
vKV{ $|  
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} F6h/0i  
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//线程睡眠 yO%VzjJhg  
public static void sleep(int nSecond) _4A&%>   
{
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try{ OQ 0b$qw  
Thread.sleep(nSecond); <C2c"=b  
} uFa-QG^Y{  
catch(Exception e) $jDD0
<F.#  
{ /Ir 7 DZK  
e.printStackTrace (); \>_eEZ5  
} 7jD@Gp`" 3  
} !WDn7j'A  
8~rT  
//日志 _qdWQFuM  
public static void log(String sMsg) S:DcfR=a  
{ | H5Ync[s  
System.err.println(sMsg); uV#-8a5!  
} 6NP`P jR  
an #jZ[  
1"N/ZKF-x  
public static void log(int sMsg) vQE` c@^{  
{ 4h[2C6 \+`  
System.err.println(sMsg); UEk|8yq  
} 1/F<T  
} )I^)*(}  
8Fyc#Xo8  
1j_aH#Fz:  
/* 8kKRx  
**TestMethod.java |Sy}d[VKsZ  
*/ xUV_2n+  
package NetFox; jTGS6{E  
gt(X!iN]  
.oW~:mY  
public class TestMethod { #h}
IUR  
S+4I[|T]Y  
j=zU7wz)D  
public TestMethod() 6tCV{pgm  
{ ///xx/weblogic60b2_win.exe qhv4R|)  
try{ #w[q.+A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !c3Qcva  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); VhJyWH%(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5+#?7J1  
fileFetch.start(); 
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}
"oKj~:$  
catch(Exception e){e.printStackTrace ();} !]UU;8h~  
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^loF#d=s  
} #Q!c42}M  
Z:r$;`K/  
kfG65aa>_  
public static void main(String[] args) !nqm ;96  
{ EusfgU:  
new TestMethod(); 96([V|5K  
} E:LQ!  
} %<bG%V(  
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