http断点续传简单实现（java)

/* 2}^+]5  
**SiteFileFetch.java =ud`6{R  
*/  M*d-z  
package NetFox; wXc,FD$  
import java.io.*; ~?FK ; (  
import java.net.*; )-0[ra]  
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public class SiteFileFetch extends Thread { 84iJ[F
q{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "Jb3&qdU  
long[] nStartPos; //开始位置 LWD.  
long[] nEndPos; //结束位置 V-[2jC{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^[ET&"  
long nFileLength; //文件长度 q&u$0XmV  
boolean bFirst = true; //是否第一次取文件  qovQ9O  
boolean bStop = false; //停止标志 VVs{l\$=ZV  
File tmpFile; //文件下载的临时信息 CXBzX:T?#  
DataOutputStream output; //输出到文件的输出流 fucUwf\_  
YV*b~6{d  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） j._G7z/LJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;5<P|:^  
{ 0r1g$mKb  
siteInfoBean = bean; Xa4GqV9M/-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); FI\IY R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); '4$lL6ly>  
if(tmpFile.exists ()) gzor%)C  
{ ppEJs  
bFirst = false; / >%L[RJ4  
read_nPos(); O4T'o.  
} smV!y8&  
else Was'A+GZ  
{ hQJo~'W=  
nStartPos = new long[bean.getNSplitter()]; DYX-5~;!  
nEndPos = new long[bean.getNSplitter()]; /E)9v$!  
} Z,3 CC \  
<lFdexH"T  
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} !&W|myN^  
(/'h4KS@  
 KZ]r8  
public void run() .%_)*NUZ  
{ $)Wb#B  
//获得文件长度 @\ }sb]  
//分割文件 PJCnud F  
//实例FileSplitterFetch P2Onkl  
//启动FileSplitterFetch线程 NW)M?f+6  
//等待子线程返回 7UnzIe  
try{ 5lO^;.cS,  
if(bFirst) %8 qSv%_  
{ t')h{2&&!2  
nFileLength = getFileSize(); (]OFS;%  
if(nFileLength == -1) f7Zf}1|  
{ 3)y{n%
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System.err.println("File Length is not known!"); uMHRUi  
} j$+gq*I&E  
else if(nFileLength == -2) aRX  
{ 3x![8 x  
System.err.println("File is not access!"); )6G"*  
} Oo kxg *!5  
else i-,'.w  
{ pzg&/m&F`  
for(int i=0;i<nStartPos.length;i++) ^1.7Juvb  
{ $:e)$Xnn-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P])L8zK  
} s{ =5-:  
for(int i=0;i<nEndPos.length-1;i++) wk@yTTnb  
{ ^T{8uJ'kn  
nEndPos = nStartPos[i+1]; ?NlSeh  
} sYW[O"oNi  
nEndPos[nEndPos.length-1] = nFileLength; }C_
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} gGmxx,i  
} ~Zmi(Ra  
{EL'd!v7e  
-Un=TX  
//启动子线程 YwXXXh  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; N#UXP5
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for(int i=0;i<nStartPos.length;i++) %[XY67A3I  
{ ?I\v0H*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t=i/xG:5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Y#`Lcg+r,  
nStartPos,nEndPos,i); awFhz 6   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?ql2wWsQO  
fileSplitterFetch.start(); dgslUg9z3g  
} l DnMjK\M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z:|9N/>T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); v J-LPTB  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S*g`d;8gV  
nEndPos = " + nFileLength); 8)Zk24:])_  
// fileSplitterFetch[nPos.length-1].start(); #X5hSw;  
xorTL8  
T/5"}P`  
//等待子线程结束 7b46t2W<  
//int count = 0; q3)wr%!k5D  
//是否结束while循环 HlPG3LD!  
boolean breakWhile = false; e/>:K' {  
qOi5WX6F/  
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while(!bStop) # kEOKmO  
{ [sj VRW-  
write_nPos(); G'9{a'  
Utility.sleep(500); JOHRmfqR  
breakWhile = true; H|`R4hAk  
&bLC(e]  
?q!FG(  
for(int i=0;i<nStartPos.length;i++) ~.6|dw\p!  
{ Y\p$SN  
if(!fileSplitterFetch.bDownOver) @!<d0_dnC  
{ AW/wI6[T  
breakWhile = false; /$:U$JVb?l  
break; z]$>+MH_  
} 13a(FG  
} [4XC#OgA  
if(breakWhile) vbp-`M
(  
break; ;v_V+t<$  
O:^'x*}  
l E^*t`+  
//count++; c#QFG1  
//if(count>4) qo_]ZKL44  
// siteStop(); JKy#j g:#  
} ue6d~8&  
$KX[Zu%  
EZib1g&:R/  
System.err.println("文件下载结束！"); sofu  
} kaQ2
A  
catch(Exception e){e.printStackTrace ();} 9tk" :ld  
} 9!}q{2j  
G52Z)^  
`(DJs-xD  
//获得文件长度 MCU9O  
public long getFileSize() s4$X  
{ /.$L"u  
int nFileLength = -1; (ua q<Cvg  
try{ iCrxV{   
URL url = new URL(siteInfoBean.getSSiteURL()); #*2Rp8n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~;unpym'  
httpConnection.setRequestProperty("User-Agent","NetFox"); O!^; mhy"  
w^{!U  
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int responseCode=httpConnection.getResponseCode(); CCqT tp  
if(responseCode>=400) WeC(w+}p  
{ &g0g]G21*I  
processErrorCode(responseCode); I60DUuF  
return -2; //-2 represent access is error Z^#]#f  
} ^VI,C|  
#mLuU  
ia4k:\  
String sHeader; ntGq" o  
})[($$f/  
P^[/Qi}j  
for(int i=1;;i++)  AmcC:5  
{ Q\9K2=4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wqy^8N[K]  
//Utility.log(in.readLine()); %{C)1*M7  
sHeader=httpConnection.getHeaderFieldKey(i); >SDpuG&>  
if(sHeader!=null) _ 08];M|  
{ 2a`J%A  
if(sHeader.equals("Content-Length")) *eUc.MX6x  
{ ~Ltr.ci  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _]|Qec)  
break; <9ifPSvJ  
} B4yh3cf  
} )X5(#E  
else EGS%C%>l/o  
break; XP?*=Z]  
} </s,pe79B  
} maC>LBa2/  
catch(IOException e){e.printStackTrace ();} >"("*3AO  
catch(Exception e){e.printStackTrace ();} Zw$ OKU  

\[#t<dD  
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Utility.log(nFileLength); v
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_k2w(ew?  
return nFileLength; f=aIXhiYU  
} ?QpNjsF  
S~3\3qt$  
mqFq_UX/T  
//保存下载信息（文件指针位置） ;&f1vi4  
private void write_nPos() ^od<JD4  
{ 6D/'`  
try{ Hk;-5A|9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); q`Q}yE>9  
output.writeInt(nStartPos.length); Y~qb;N\  
for(int i=0;i<nStartPos.length;i++) 5~r2sCDPk  
{
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// output.writeLong(nPos); T*CME]  
output.writeLong(fileSplitterFetch.nStartPos); uZ(? >  
output.writeLong(fileSplitterFetch.nEndPos); u~F~cDu  
} Eg8i _s~:  
output.close(); s-?fUqA  
} m22wF>9  
catch(IOException e){e.printStackTrace ();} Qn=$8!Qqa  
catch(Exception e){e.printStackTrace ();} ndi+xaQtG  
} #ia;- 3  
G/{ ~_&t
 
9%!dNnUk  
//读取保存的下载信息（文件指针位置） V'StvU  
private void read_nPos() S_Z`so}  
{ C;qMw-*F  
try{ $<w)j!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4|Ui?.4=  
int nCount = input.readInt(); 2]ti!<  
nStartPos = new long[nCount]; ::"E?CQLV  
nEndPos = new long[nCount]; i@zY9,b  
for(int i=0;i<nStartPos.length;i++) V3.t;.@  
{ zxKCVRJ  
nStartPos = input.readLong(); IOEM[zhb$  
nEndPos = input.readLong(); ;/sHWI f+Z  
} Cs1>bpY*R6  
input.close(); n&!+wcJ;Yt  
} S
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catch(IOException e){e.printStackTrace ();} {p/YCch,  
catch(Exception e){e.printStackTrace ();} ]vo_gKZ  
} A3+6#?:;  
$sgH'/>  
,rO[mNk9@  
private void processErrorCode(int nErrorCode) Z[ZDQ o1  
{ g7V_[R(6  
System.err.println("Error Code : " + nErrorCode); rK|*hcy  
} va,~w(G  
7NF/]y4w  
kGHC]Fb)  
//停止文件下载 |_zO_Frtp  
public void siteStop() 5 9-!6;T  
{ O#_x)13  
bStop = true; ([LIjaoi  
for(int i=0;i<nStartPos.length;i++) b{&FuvQg2  
fileSplitterFetch.splitterStop(); '3;v] L?G  
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u#jC#u^M  
} +)/Uu3"=  
} {#hVD4$b  
//负责部分文件的抓取 1"]P`SY$r  
**FileSplitterFetch.java wahZK~,EaY  
*/ rFu ez$  
package NetFox; K=\&+at1  
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import java.io.*; j_Nm87i]  
import java.net.*; n1J]p#nCa.  
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fRHKQ(a#  
public class FileSplitterFetch extends Thread { tXq)nfGe{  
!OE*z $\  
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String sURL; //File URL l(:kfR~AC  
long nStartPos; //File Snippet Start Position 2\@Z5m3B  
long nEndPos; //File Snippet End Position Y&f\VNlT  
int nThreadID; //Thread's ID 6|=j+rScv  
boolean bDownOver = false; //Downing is over ];FtS>\x  
boolean bStop = false; //Stop identical "H+,E_&(  
FileAccessI fileAccessI = null; //File Access interface ijW7c+yd  
' 4O
-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ZGz|m0b (  
{ a5?8QAO~r  
this.sURL = sURL; oU+F3b}5p  
this.nStartPos = nStart; eegx'VS
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this.nEndPos = nEnd; jk70u[\  
nThreadID = id; S/gm.?$V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 nhH;?D3  
} ]U_
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^T079=$5  
4gZ&^y'  
public void run() OW5t[~y]  
{ q7Es$zjX  
while(nStartPos < nEndPos && !bStop) _vl}*/=Hc  
{ 4JMiyiW&  
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yyP-=Lhmo=  
try{ iRw&49  
URL url = new URL(sURL); r>|-2}{N/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @;)PSp*j  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;y1Q6eN  
String sProperty = "bytes="+nStartPos+"-"; ~5OL6Bi-q  
httpConnection.setRequestProperty("RANGE",sProperty); 1r9f[j~  
Utility.log(sProperty); -5Utlos  
|b.z*G  
a.kbov(  
InputStream input = httpConnection.getInputStream(); f)NHM'  
//logResponseHead(httpConnection); K+d2m9C=  
jRj=Awy  
97`WMs
  
byte[] b = new byte[1024]; JUt7En;XE  
int nRead; M+Uyb7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Mi0sC24b|  
{ K-Mc6  
nStartPos += fileAccessI.write(b,0,nRead); S
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//if(nThreadID == 1) 63&^BW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HlB]38  
} P+(i^=S  
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S
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Utility.log("Thread " + nThreadID + " is over!"); RFfIF]~3  
bDownOver = true; @;^Y7po6u  
//nPos = fileAccessI.write (b,0,nRead); cxP
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} y8 E}2/  
catch(Exception e){e.printStackTrace ();} ?Rr2/W#F  
} [EZYsOr.  
} %&+59vq   
HuI`#.MpWE  
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f  
//打印回应的头信息 h*l&RR:i  
public void logResponseHead(HttpURLConnection con) w
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{ ^k/i-%k0  
for(int i=1;;i++) Op}ZB:  
{ GDhM<bVqM*  
String header=con.getHeaderFieldKey(i); U@-2Q=  
if(header!=null)
|m*.LTO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ciihsm  
Utility.log(header+" : "+con.getHeaderField(header)); bbN%$/d  
else 77,oPLSn  
break; FxW&8 9G  
} B$a-og(  
} 8OFj0S1r`  
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o
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public void splitterStop() H3KTir"on  
{ nHst/5dA  
bStop = true; xvm5  
} h5~n 1qX  
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} P~ 0Jg# V  
:#{Xuy:  
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/* F4C!CUI  
**FileAccess.java +l0g`:  
*//文件访问(定位，写) 93Yn`Av;  
package NetFox; SaDA`JmO  
import java.io.*; 3YL l;TP_  
l|"6yB |  
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public class FileAccessI implements Serializable{ "&o,yd%  
2xxB\J  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9Sg<K)Mc  
RandomAccessFile oSavedFile; >hsuAU.UOR  
long nPos; [~mGsXV  
F jrINxL7^  
AR&:Q4r|  
public FileAccessI() throws IOException +]wuJSxc  
{ q9*MNHg}  
this("",0); <M+R\SH-  
} CboLH0Fa  
I-@?guZ r  
S\x=&Rz  
public FileAccessI(String sName,long nPos) throws IOException p9[6^rjx8  
{ ;y>a nE}n{  
oSavedFile = new RandomAccessFile(sName,"rw"); x4kWLy7Sz  
this.nPos = nPos; /@oLe[Mz$  
oSavedFile.seek(nPos); n=sXSxl  
} 1TN}GsAj  
a\5FAkI  
{E_{JB~`  
public synchronized int write(byte[] b,int nStart,int nLen) 2KJ1V+g@a6  
{ `N87h"  
int n = -1; 5
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try{ 8*a), 3aK  
oSavedFile.write(b,nStart,nLen); pbk$o{$`W  
n = nLen; l]LxL  
} 4ne5=YY*  
catch(IOException e) t;q7t!sC]  
{ n
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e.printStackTrace (); JMa3btLy(  
} iz^qR={bW  
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return n; k5BXirB  
} 3'I^lc  
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} t%VDRZo7  
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GHc/Zc"iX  
/* ?A*Kg;IU  
**SiteInfoBean.java +Wn&,?3^  
*/ D{7w!z  
package NetFox; Qst$S}n  
oF:v JDSS  
Wr~yK? : ]  
public class SiteInfoBean { Nn6S 8kc  
$W8Cf[a  
;O#g"8  
private String sSiteURL; //Site's URL cu9Qwm  
private String sFilePath; //Saved File's Path _S?qDG{E|  
private String sFileName; //Saved File's Name
OYL]j{  
private int nSplitter; //Count of Splited Downloading File E#%}ZY  
S -&)p@4  
8/%6@Y"Y*  
public SiteInfoBean() :py\|  
{//nSplitter的缺省值为5 PRu&3BP  
//default value of nSplitter is 5 hUpnI@  
this("","","",5); c/3
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}
;/O#4]2*  
lx0~>K]  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) UmU:j@xvg  
{ S]/b\B.h+  
sSiteURL= sURL; n%%7KTqu  
sFilePath = sPath; ?;ukvD  
sFileName = sName; -.I4-6~  
this.nSplitter = nSpiltter; h)(*q+a  
!kuX,*}q  
N;sm*+r  
} cD}Sf>  
W#F Q,+0)  
w`HI]{hE~N  
public String getSSiteURL() P87# CAN  
{ )q~DT
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return sSiteURL; C}}/)BYi  
} k%'m*Tf  
3\$wdUFr  
2B1xUj ]  
public void setSSiteURL(String value) yJx?M  
{ VU.@R,  
sSiteURL = value; @J'YV{]  
} +=$  
9i$NhfOe  
<v 0*]NiX  
public String getSFilePath() /#LW"4;*  
{ #E7AmmqD%  
return sFilePath; =Ufr^naA  
} 9/ovKpY  
R3.*dqo$  
CON0E~"  
public void setSFilePath(String value) "h"NW[R  
{ T<b+s#n4  
sFilePath = value; []kN16F  
} AIijCL  
n| !@1sd  
!vD{Df>  
public String getSFileName() AasZuO_I  
{ `RRE(SiKU  
return sFileName; R=j% S!  
} BHFY%6J!  
f2I6!_C!+  
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public void setSFileName(String value) v}JD2.O+  
{ yzsab ^]  
sFileName = value; K{fsn4rk  
} &K+0xnUH  
RD,5AShP  
|`d0^(X  
public int getNSplitter() A Io|TD5{~  
{ Q%S9fq,q  
return nSplitter; jvy$t$az  
} XL}"1lE  
*>8ce-PV  
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public void setNSplitter(int nCount) 6=hk=2]f  
{  Y k7-`  
nSplitter = nCount; oFsM6+\/S  
} '])2k@o@  
} O\KQl0*l\\  
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/* &[mZD,  
**Utility.java ./6<r OW  
*/ 0C%W&;r0  
package NetFox; AV8T  
|Hr:S":9  
o]n!(f<(*  
public class Utility { sM[I4.A3  
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WG71k8af  
public Utility() \G@wp5  
{ UO Ug4  
K5t0L!6<+  
!5@_j,lW(  
} G_H?f\/  
VhGs/5  
//线程睡眠 =DbY?Q<Q  
public static void sleep(int nSecond) `/&SxQB<  
{ Z;Rp+X  
try{ pv!oz2w1  
Thread.sleep(nSecond); [%A4]QzWh  
} ?(6mVyIe  
catch(Exception e) C#V ~Y  
{
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e.printStackTrace (); \VMD$zZx  
} Ty(@+M~-  
} 4674SzL  
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//日志 #L}+H!Myh  
public static void log(String sMsg) V D?*h  
{ Uh1NO&i.W  
System.err.println(sMsg); HL3XyP7  
} '|>9C^E9X  
N/QiI.V6  
LK9g0_  
public static void log(int sMsg) $4FX(O0Q@  
{ 8e~|.wOL  
System.err.println(sMsg); g?v\!/~(u  
} Lw7=+h)  
} V! |qYM.  
>kZ57,  
qB]i6*  
/* ^E`(*J/o  
**TestMethod.java fQK"h  
*/ rx"s!y{!-  
package NetFox; Mp$@`8X`  
 ,B<l  
nz1'?_5  
public class TestMethod { )+")Sz3zx  
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public TestMethod() ]j~"m
FAP  
{ ///xx/weblogic60b2_win.exe y)c5u%(  
try{ p}b/XnV$~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }U w&Ny  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `~UZU@/x  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |tzg:T;  
fileFetch.start(); bOp54WI-g  
} 1{Mcs%W;w5  
catch(Exception e){e.printStackTrace ();} 5F|8?BkOL^  
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$QEilf;E  
} /%aiEhL  
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public static void main(String[] args) 3=Ec"  
{ <mMTD8Sx]  
new TestMethod(); P|2E2=G  
} %Pqk63QF  
} F 09DV<j  
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