http断点续传简单实现（java)

/* &qV_|f;  
**SiteFileFetch.java .Zx7+`i  
*/ VKr oikz@]  
package NetFox; &RlYw#*1.  
import java.io.*; 6w0r)  
import java.net.*; ~gEd(  
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public class SiteFileFetch extends Thread { mTa
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SiteInfoBean siteInfoBean = null; //文件信息Bean "'c =(P  
long[] nStartPos; //开始位置 sv*xO7D.  
long[] nEndPos; //结束位置 *L5L.: Z
e  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z"!=A}i  
long nFileLength; //文件长度 B 3eNvUFZg  
boolean bFirst = true; //是否第一次取文件 L_AQS9a^D  
boolean bStop = false; //停止标志 c`V~?]I>  
File tmpFile; //文件下载的临时信息 M'
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DataOutputStream output; //输出到文件的输出流 Lw{'mtm  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） v
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public SiteFileFetch(SiteInfoBean bean) throws IOException ,)}-mu  
{ iu'rc/=V  
siteInfoBean = bean; 3]/Y=A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `{\10j*B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); i'0ol^~y6  
if(tmpFile.exists ()) j"<F?k@`Q  
{ [u8JqX  
bFirst = false; V[">SiOg  
read_nPos(); 1L.yh U\  
} +C(/.X Kz%  
else E2|c;{c  
{ oz?6$oE(bt  
nStartPos = new long[bean.getNSplitter()]; M+\LH  
nEndPos = new long[bean.getNSplitter()]; 5?MKx!%  
} !%YV0O0  
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} p:qj.ukw  
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public void run() q*{Dy1Tj  
{
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//获得文件长度 -cWxS{vO  
//分割文件 JOH=)+xj  
//实例FileSplitterFetch LwIX&\Ub  
//启动FileSplitterFetch线程 L3X[; |v}  
//等待子线程返回 f<( ysl1[  
try{ n5 jzVv  
if(bFirst) y:8Oc?  
{ z,=k F I  
nFileLength = getFileSize(); .JL?RH2@8  
if(nFileLength == -1) RLbxNn  
{ @&]%%o+  
System.err.println("File Length is not known!"); Qtn%h:i S~  
} 2aO.t  
else if(nFileLength == -2) Hh.l,Z7i7D  
{ V s1Z$HS`  
System.err.println("File is not access!"); TfqQh!Y  
} NpYzN|W:  
else [ f`V_1d3  
{ "npLl]XM  
for(int i=0;i<nStartPos.length;i++) . xdSUe  
{ Tg.}rNA4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 626!6E;T  
} (SYSw%
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for(int i=0;i<nEndPos.length-1;i++) <f`G@  
{ -AxO1 qO  
nEndPos = nStartPos[i+1]; ~m.@{Do0p  
} <lwkjt=RV  
nEndPos[nEndPos.length-1] = nFileLength; khtSZ"8X  
} j]5bs*G  
} v}\Nx[}  
?)B\0` %*'  
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//启动子线程 {QTnVS't 0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4&([<gyR<  
for(int i=0;i<nStartPos.length;i++) !5K9L(gqb  
{ 9;u&,R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }e*OprF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), X,h"%S<c#H  
nStartPos,nEndPos,i); KPSHBv-#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ];1Mg  
fileSplitterFetch.start(); m`Ver:{  
} 8z h{?0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rik0F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $Y5m"wySZ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d%:   
nEndPos = " + nFileLength); pT`oC&  
// fileSplitterFetch[nPos.length-1].start(); O o+pi$W  
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L)
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//等待子线程结束 mxJ& IV  
//int count = 0; qE&R.I!o  
//是否结束while循环 4R/cN'-  
boolean breakWhile = false; y
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while(!bStop) [~<X|_LG  
{ U6@Hgi>  
write_nPos(); B#T4m]E/  
Utility.sleep(500); 8vLaSZ="[  
breakWhile = true; Yq?FiE0  
VgO:`bDF  
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for(int i=0;i<nStartPos.length;i++) ?@i_\<A2  
{ ]FNqNZ  
if(!fileSplitterFetch.bDownOver) sox0:9Oqnf  
{ $Dm2>:D
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breakWhile = false; j!:^+F/  
break; &6`h%;a/&  
} 58@YWvAk  
} R6A{u(  
if(breakWhile) =k\V~8XZ  
break; fGtUr_D  
j:;[Y`2  
:"9P {xe^  
//count++; $R2iSu{kO  
//if(count>4) W5^m[,GU'  
// siteStop(); w+NdEE4H9z  
} MM*B.y~TxZ  
.A. VOf_  
"[rChso  
System.err.println("文件下载结束！"); Hq*\,`b&  
} uwcm%N;I"  
catch(Exception e){e.printStackTrace ();} ^"e|)4_5\  
} Is $I;`  
^T#bla893  
#ONad0T;  
//获得文件长度 .W#
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public long getFileSize() Oist>A$Z  
{ <B?@,S>  
int nFileLength = -1; -<[MM2Y  
try{ j<-#a^jb  
URL url = new URL(siteInfoBean.getSSiteURL()); mu[:b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); msyC."j0jU  
httpConnection.setRequestProperty("User-Agent","NetFox"); qBKRm0<W  
1'[RrJ$Q  
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int responseCode=httpConnection.getResponseCode(); -r6cK,WVU  
if(responseCode>=400) t0 1@h_WS  
{ NT6OGBl&  
processErrorCode(responseCode); 1gwnG
&  
return -2; //-2 represent access is error
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} IezOa
l  
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String sHeader; R;wq
 
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for(int i=1;;i++) jo8hVWJ7V*  
{ <,r|*pkhp~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %MQU&H9[  
//Utility.log(in.readLine()); &o$z[b  
sHeader=httpConnection.getHeaderFieldKey(i); gkJL=,  
if(sHeader!=null) QxSJLi7t  
{ h~]G6>D9)>  
if(sHeader.equals("Content-Length")) OO Hw-MW  
{ ]ZD W+<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `u zR!^X  
break; "B~c/%#PH  
} '@$YX*[
 
} 0UJ%tPS  
else WUwH W  
break; []'gIF  
} 8!~8:?6n  
} g[]UM;D*  
catch(IOException e){e.printStackTrace ();} N%hV+># Z  
catch(Exception e){e.printStackTrace ();} eF[CiO8F2  
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Utility.log(nFileLength); 9w^lRbn  
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return nFileLength; cmLGMlFT  
} raWs6b4Q  
^PnXnH?  
r\OunGUP  
//保存下载信息（文件指针位置） WIe7>wkC  
private void write_nPos() cBZKt  
{ n9 LTrhLqp  
try{ x)Y?kVw21"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); iP7 Cku}l  
output.writeInt(nStartPos.length); 5s=ZA*(sY  
for(int i=0;i<nStartPos.length;i++) CFm( yFk  
{ NUlp4i~Q  
// output.writeLong(nPos); D5o[z:V7"  
output.writeLong(fileSplitterFetch.nStartPos); S>-x<'Os  
output.writeLong(fileSplitterFetch.nEndPos); Z*+0gJ<Y  
} i`m&X6)\j  
output.close(); ?ztI8I/  
} BB x359  
catch(IOException e){e.printStackTrace ();} XX85]49`%  
catch(Exception e){e.printStackTrace ();} BGtr=&Hq  
} B6N/nCvHK  
-C]k
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//读取保存的下载信息（文件指针位置） ^#|Sl D]  
private void read_nPos() $pKlF0 .  
{ KASuSg+  
try{ +-DF3(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OcA_m.  
int nCount = input.readInt(); |WiE`&?xP  
nStartPos = new long[nCount]; h
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nEndPos = new long[nCount]; z%)~s/2Rs  
for(int i=0;i<nStartPos.length;i++) 1JRM@!x  
{ rq>}] U  
nStartPos = input.readLong(); )\S3Q  
nEndPos = input.readLong(); o!]muO*Rm  
} QKW\z aG  
input.close(); 5r&bk`  
} }Y}f73-|  
catch(IOException e){e.printStackTrace ();} }McqoZ%F  
catch(Exception e){e.printStackTrace ();} :3J0Q  
} ~XzT~WxW  
;PS V3Zh  
v qt#JdPp9  
private void processErrorCode(int nErrorCode) 'n:|D7t  
{ Vu0d\l^$  
System.err.println("Error Code : " + nErrorCode); M id v  
} yQT cO^E  
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1zGD~[M  
//停止文件下载 O$qxo &  
public void siteStop() &kR*J<)V  
{ 8t1XZ  
bStop = true; S55h}5Y  
for(int i=0;i<nStartPos.length;i++) \;!}z3Ww  
fileSplitterFetch.splitterStop(); J?wCqA  
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} j8cIpbp8x  
} ^n|yfvR  
//负责部分文件的抓取 3X;k c>  
**FileSplitterFetch.java w#XD4kwQG  
*/ "{;E+-/ aL  
package NetFox; wtl3Ex,DO  
=JkPE2
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diz=|g=w  
import java.io.*; Wbq0K6X  
import java.net.*; 5*O*p `Ba  
43VBx<"  
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public class FileSplitterFetch extends Thread { _%@dlT?  
AV>_bw.  
|p .o^  
String sURL; //File URL [!~=m  
long nStartPos; //File Snippet Start Position !*?|*\B^I  
long nEndPos; //File Snippet End Position ]c9\[Kdq}H  
int nThreadID; //Thread's ID &<=?O a  
boolean bDownOver = false; //Downing is over wit rC>  
boolean bStop = false; //Stop identical HBdZE7.x)3  
FileAccessI fileAccessI = null; //File Access interface CN{xh=2qY[  
d-sT+4o}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5%_aN_1?ef  
{ 22T\-g{  
this.sURL = sURL; h-f`as"d  
this.nStartPos = nStart; `f[  
this.nEndPos = nEnd; EED0U?  
nThreadID = id; :>|dE%/e$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `j1b5&N;7  
} 0"F|)  
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public void run() &-$27  
{ fTOGW`s^  
while(nStartPos < nEndPos && !bStop) 7DKTd^^M  
{ 83adnm  
+SB>
>  
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try{ %/4_|.8u  
URL url = new URL(sURL); ]vflx^<?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xZ]QT3U+  
httpConnection.setRequestProperty("User-Agent","NetFox"); Yyr qO^9m  
String sProperty = "bytes="+nStartPos+"-"; k-N}tk/5  
httpConnection.setRequestProperty("RANGE",sProperty); !X[P)/?b0+  
Utility.log(sProperty); ,Y4>$:#n/  
&7 K=  
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InputStream input = httpConnection.getInputStream(); &z]x\4#,  
//logResponseHead(httpConnection); H%bc.c  
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;u-[%(00S  
byte[] b = new byte[1024]; 2<T/N  
int nRead; LPeVr^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -N'wKT5  
{ F%:74.]Y  
nStartPos += fileAccessI.write(b,0,nRead); l*$~Y0  
//if(nThreadID == 1) bZ>dr{%%e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _P`
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} T)I\?hqTB  
<}p]0iA  
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Utility.log("Thread " + nThreadID + " is over!"); '~9w<dSB!r  
bDownOver = true; `Frr?.3&-  
//nPos = fileAccessI.write (b,0,nRead); !,^y!+,Qy  
} x*sDp3f[*  
catch(Exception e){e.printStackTrace ();} ;:,U]@  
} ?Rk[P cX<  
} uznYLS  
ICEyz| C  
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//打印回应的头信息 1u8hnG  
public void logResponseHead(HttpURLConnection con) +MqJJuWB  
{ O I0N(V  
for(int i=1;;i++) 'T|EwrS j  
{ !Ln 'Mi_B  
String header=con.getHeaderFieldKey(i); hD[r6c  
if(header!=null) AHo}K\O?r  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (;;.[4,y  
Utility.log(header+" : "+con.getHeaderField(header)); f5Hv![x  
else >"+ho  
break; Q;s{M{u  
} ]8htL#C  
} 4TTrHs  
+c8t~2tuN  
P}^Y"zF2  
public void splitterStop() (5;nA'  
{ gt9(5p  
bStop = true; ucJ}KMz  
} NM9,AG  
ify48]  
\:g\?[   
} 0CvGpM,  
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/* ${rWDZ0Z  
**FileAccess.java k 1a?yH)=  
*//文件访问(定位，写) Ai"MJ6)  
package NetFox; qW4DW4  
import java.io.*; dW22v!  
>& 4):  
/1p5KVTKv  
public class FileAccessI implements Serializable{ ff7#LeB9  
<5"&]! .  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^We}i  
RandomAccessFile oSavedFile;
+_{cq@c  
long nPos; {P,hH~!  
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public FileAccessI() throws IOException lQiw8qD  
{ bIlNA)g  
this("",0); &uF~t |!c  
} 1KY0hAx  
5 1N/XEk  
=''WA:,=h  
public FileAccessI(String sName,long nPos) throws IOException Ir-QD!!<  
{ XdmpfUR,13  
oSavedFile = new RandomAccessFile(sName,"rw"); P*B@it  
this.nPos = nPos; 2 6DX4  
oSavedFile.seek(nPos); 5}Id[%.x  
} ;5.<M<PH  
?PS?_+E\L  
Lq$ig8V:O7  
public synchronized int write(byte[] b,int nStart,int nLen) yMu G? x+  
{ (7N!Jvg9  
int n = -1; 71>,tq  
try{ 7_P33l8y  
oSavedFile.write(b,nStart,nLen); {8qcM8  
n = nLen; zRd.!Rv  
} zy%0;%
 
catch(IOException e) "O-X*>?f  
{ oc]:Ty  
e.printStackTrace (); 2S~(P  
} {]cr.y]\  
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';Q8x?BS  
return n; iqdU?&.;  
} hJ]Oa7r  
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} MUsF  
9a=>gEF],@  
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/* NtM ?Jh  
**SiteInfoBean.java Zj-U^6^L  
*/ 1x=x,lcL  
package NetFox; 7V8k =  
RD"-(T  
}:{9!RMO  
public class SiteInfoBean { j{r@>g;3  
?>U=bA  
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private String sSiteURL; //Site's URL (&Jo. <  
private String sFilePath; //Saved File's Path (CRx'R  
private String sFileName; //Saved File's Name Bm,Vu 1]t  
private int nSplitter; //Count of Splited Downloading File $OdBuJA  
'tw
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public SiteInfoBean() x>B\2;  
{//nSplitter的缺省值为5 ^\Z+Xq1~/  
//default value of nSplitter is 5 [T,^l#S1  
this("","","",5); eUZk|be  
} 3~bB2APk  
WA,D=)GP  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ex zB{"  
{ "^6Fh"]
 
sSiteURL= sURL; O1c:X7lHc  
sFilePath = sPath; HV)aVkr/&  
sFileName = sName; &z1U0uk  
this.nSplitter = nSpiltter; tuIZYp8tIN  
,pI9=e@O/z  
HUD0 @HQI  
} Li}5aK  
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public String getSSiteURL() {pH#zs4Y  
{ *E
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return sSiteURL; ~WTkX(\  
} 8ta@@h  
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/q\e&&e  
public void setSSiteURL(String value) ~a[/l  
{ bA,Zfsr6#  
sSiteURL = value; mi<Q3;m  
} X*@
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public String getSFilePath() 18sc|t  
{ 5]LWWjT  
return sFilePath; _3@5@1[s  
} K&%CeUa  
vE'{?C=EM  
:K]7(y7>  
public void setSFilePath(String value) jhf3(hx&F  
{ 9/29>K_  
sFilePath = value; ceE]^X;p  
} c?HUW  
^@AyC"K  
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public String getSFileName() I:iMRvp  
{ N4C7I1ihq  
return sFileName; =n"kgn  
} |EX=Rj*  
}q@#M8b  
i,*m(C@F}  
public void setSFileName(String value) 9;U?_   
{ t kj  
sFileName = value; Y /_CPY  
} LZe)_9$  
Na/Y1RW  
iOURS  
public int getNSplitter() w'(/dr  
{ Xj/z),  
return nSplitter; *"8Ls0!  
} B+`4UfB]Z}  
)xyjQ|b  
%r(WS_%K|  
public void setNSplitter(int nCount) )e?&'wa>  
{ lUs$I{2_  
nSplitter = nCount; u3+B/ 5x  
} tj@(0}pi4  
} 1B2#uhT]r  
v>} +->f  
b^d{$eoH?|  
/* H"l4b4)N\  
**Utility.java rvd$4l^  
*/ WqNXE)'  
package NetFox; %/y=_G  
#mu L-V  
(~^fx\
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public class Utility { 2uE<mjCt-r  
f(m,!  
7amVnR1f  
public Utility() |cma7q}p  
{ OY`B{jV-  
KN|<yF   
}<A.zwB<i  
} Cr7Zi>sd<!  
6^]|  
//线程睡眠 <@-O06  
public static void sleep(int nSecond) 8O,\8:I#  
{ Yao}Xo9}  
try{ f?sm~PwC-  
Thread.sleep(nSecond); o2ggHZe/=@  
} Bxm,?=h  
catch(Exception e) (CxA5u1|l  
{ :uo1QavO@,  
e.printStackTrace (); N2}SR|.  
} H/O.h@E4X  
} Kk8}m;  
~U&NY7.@  
//日志 AYA{_^#+3  
public static void log(String sMsg) ,D+ydr  
{ W%g*sc*+  
System.err.println(sMsg); I1E9E$m5\<  
} ljNwt  
! dzgi:  
2@zduL'do_  
public static void log(int sMsg) Sf,z  
{ pD$4nH4KST  
System.err.println(sMsg); I
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} c 3QgX4vq  
} VyxYv-$Y  
1XSnnkJm  
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/* p,fV .5q  
**TestMethod.java Wm}c-GD  
*/ V^2_]VFj  
package NetFox; =#G 2}8mQD  
t_3j_`  
Q*smH-Sw  
public class TestMethod { m;OvOc,  
j~qm$'H  
X,|8Wpi=  
public TestMethod() FXof9fa_B  
{ ///xx/weblogic60b2_win.exe YJ _eE  
try{ C$y6^/7)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YvU%OO-+,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); cJ96{+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); p`Pa;=L  
fileFetch.start(); ~$HB}/  
} Y_'ERqQ  
catch(Exception e){e.printStackTrace ();} x4
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} g<:Lcg"u  
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public static void main(String[] args)
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{ 7]h%?W!  
new TestMethod(); h&<"jCjL
 
} $xbC^ k  
} 9pp+<c  
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