http断点续传简单实现（java)

/* 0N]\f.=`  
**SiteFileFetch.java 6f t6;*,  
*/ j, *=D6  
package NetFox; o!&+ _BKw  
import java.io.*; oxUBlye  
import java.net.*; (F3R!n  
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public class SiteFileFetch extends Thread { }7xcHVO8-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean J,=ZUh@M  
long[] nStartPos; //开始位置 %] :ZAmN  
long[] nEndPos; //结束位置 G^.tAO5:f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <R~;|&o,$  
long nFileLength; //文件长度 MZWv#;.]  
boolean bFirst = true; //是否第一次取文件 8X278^ #  
boolean bStop = false; //停止标志 x&
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File tmpFile; //文件下载的临时信息 }L%2K"8?}  
DataOutputStream output; //输出到文件的输出流 darbL_1  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ]Wjcr2Wq  
public SiteFileFetch(SiteInfoBean bean) throws IOException Bga4kjfmk  
{ to1r 88X  
siteInfoBean = bean; jaavh6h)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); q"S,<I<f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); IGlyx'\_  
if(tmpFile.exists ()) PY3bn).uR  
{ AGO"),  
bFirst = false; voTP,R[}85  
read_nPos(); zKaj<Og  
} Y}Dk>IG  
else a"t~
K  
{ T2tvU*[=  
nStartPos = new long[bean.getNSplitter()]; {^:NII]  
nEndPos = new long[bean.getNSplitter()]; vfXNN F  
} R9"}-A  
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} A;&YPHB  
/EegP@[  
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public void run() 
7&%HE\  
{ #N~1Ye  
//获得文件长度 nG{o$v_|  
//分割文件 5~im.XfiVx  
//实例FileSplitterFetch 0 VG;z#{J  
//启动FileSplitterFetch线程 @0NWc c+  
//等待子线程返回 l%?4L/J)#  
try{ ,w9|?%S  
if(bFirst) Z5*(xony0  
{ gN73)uJ0  
nFileLength = getFileSize(); b353+7"|  
if(nFileLength == -1) 'iOaj0f  
{ 0S'@(p[A  
System.err.println("File Length is not known!"); bKzG5|Qu  
} 6U$e;cr6  
else if(nFileLength == -2) :xbj&
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{ v<<ATs%w  
System.err.println("File is not access!"); & BY\h:  
} $/@  L  
else .}Ys+d1b9c  
{ _O11SiP]  
for(int i=0;i<nStartPos.length;i++) W,H=K##6<  
{ mpVD;)?JmM  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ])%UZM6  
} Gr)G-zE  
for(int i=0;i<nEndPos.length-1;i++) ;(;~yB|NZ5  
{ B4*y-Q.*  
nEndPos = nStartPos[i+1]; =n_z`I  
} }aI>dHL  
nEndPos[nEndPos.length-1] = nFileLength; "USzk7=&.  
} eOkiB!G.  
} gy~2LY!}  
suW|hh1/Ya  
9ZatlI,
 
//启动子线程 .O(9\3q\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; L
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for(int i=0;i<nStartPos.length;i++) @p}_"BHYWt  
{ Ex|Z@~T12  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {D :WXvI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *//z$la  
nStartPos,nEndPos,i); 6gO(  8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  98^7pa  
fileSplitterFetch.start(); C!9m
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} 4GeN<9~YS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /0Qo(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Kng=v~)N'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /FpPf[  
nEndPos = " + nFileLength); :hW(2=%  
// fileSplitterFetch[nPos.length-1].start(); W/WP }QM  
7+@-mJMP$D  
0dS(g&ZR  
//等待子线程结束 :%j"l7=>  
//int count = 0; 2EN}"Du]mj  
//是否结束while循环 CR2.kuM0~  
boolean breakWhile = false; .f. tPm  
a}|<*!4zUQ  
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while(!bStop) * a1q M?  
{ eY^zs0  
write_nPos(); -)Vy)hD,  
Utility.sleep(500);
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breakWhile = true; 2J$vX(  
V?)V2>]  
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for(int i=0;i<nStartPos.length;i++) :pz@'J  
{ ip
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if(!fileSplitterFetch.bDownOver) +|8.ymvm  
{ G|-RscPe  
breakWhile = false; h05FR[</  
break; %21|-B  
} 0kls/^0,  
} i^Jw`eAmT  
if(breakWhile) F^%\AA]8  
break; Fv$w:r]q6  
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Y"KJ`Rx  
//count++; W?P4oKsql*  
//if(count>4) 4${3e Sg_  
// siteStop(); _5(p=Zc  
} "$K]+0ryG<  
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O{7#Xj :_  
System.err.println("文件下载结束！"); 3vAP&i'I  
} <gH-`3J6  
catch(Exception e){e.printStackTrace ();} 0pW;H|h  
} ]GCw3r(!  
1|ddG010  
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//获得文件长度 &(Hw:W9  
public long getFileSize() /-^J0f+l3  
{ s"w^E\>6  
int nFileLength = -1; GE=S.P;  
try{ @"/H er  
URL url = new URL(siteInfoBean.getSSiteURL()); )dEcKH<#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #*"V'dj;e  
httpConnection.setRequestProperty("User-Agent","NetFox"); -a~n_Z>_  
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int responseCode=httpConnection.getResponseCode(); vSoG] :1  
if(responseCode>=400) \pT
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{ @]}/vsI m  
processErrorCode(responseCode); /0|1xHs  
return -2; //-2 represent access is error H_x}-  
} GVn'p Wg  
T@#?{eA  
_nxu8g]  
String sHeader; z-g6d(  
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i`];xNR'  
for(int i=1;;i++) ~7g$TAe{  
{ /Ix5`Q)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NRT]dYf"z  
//Utility.log(in.readLine()); 8<C@I/  
sHeader=httpConnection.getHeaderFieldKey(i); h?B1Emlq  
if(sHeader!=null) 3b_/QT5!  
{ #;@I.  
if(sHeader.equals("Content-Length")) Cd]A1<6s  
{ ;YMg4Cs  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); HUCJA-OZGL  
break; ^u"WWLZ  
} FyPG5-  
} cwtlOg  
else $ #GuV'  
break; [E6ceX0  
} 98?O[=  
} D2gyn-]\  
catch(IOException e){e.printStackTrace ();} U,6sR  
catch(Exception e){e.printStackTrace ();} OU#p^5K  
59W~bWHCP  
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Utility.log(nFileLength); ~ QohP`_  
h#Z,ud_  
?K2}<H-  
return nFileLength; m8R=wb :  
} } snS~kx  
/]-yZ0hX0O  
wpi$-i`  
//保存下载信息（文件指针位置） `VUJW]wGu  
private void write_nPos() j&a\ K}U!  
{ ,RY;dX-#  
try{ :i0;jWcb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); soQ[Zg4}  
output.writeInt(nStartPos.length); cjO%X  
for(int i=0;i<nStartPos.length;i++) JXq!v:w6  
{ dKU:\y  
// output.writeLong(nPos); .8%b;b  
output.writeLong(fileSplitterFetch.nStartPos); 7ZyP  
output.writeLong(fileSplitterFetch.nEndPos); RjO0*$>h  
} !7)#aXt&  
output.close(); ANM=:EtP  
} /QVwZrch  
catch(IOException e){e.printStackTrace ();} K\8zhY  
catch(Exception e){e.printStackTrace ();} U:3OE97  
} 33D2^Sf6"  
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)X|)X,~+-  
//读取保存的下载信息（文件指针位置） (y&sUc9  
private void read_nPos() }S?"mg&V  
{ Z[]8X@IPe  
try{ zF>;7'\x  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); B]()  
int nCount = input.readInt(); #>,E"-]f  
nStartPos = new long[nCount]; 6aHD?a o  
nEndPos = new long[nCount]; +/RR!vG,  
for(int i=0;i<nStartPos.length;i++) t0@AfO.'1  
{ J
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nStartPos = input.readLong(); Ok{1{EmP  
nEndPos = input.readLong(); |:x,|>/  
} La'6k  
input.close(); ~OR^  
} A?}[rM Z  
catch(IOException e){e.printStackTrace ();} P:vp/x!  
catch(Exception e){e.printStackTrace ();} `aG_m/7|  
} +WMXd.iN,  
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2  
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private void processErrorCode(int nErrorCode) 1jop;{,^  
{ } S]!W\a  
System.err.println("Error Code : " + nErrorCode); jn(!6\n"  
} $cJ fdE  
~"J1@<  
e`LkCy[_  
//停止文件下载 vxC];nCC#  
public void siteStop() 4Otq3s34FT  
{
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bStop = true; }d>.Nj#zh  
for(int i=0;i<nStartPos.length;i++) QKq4kAaJ!  
fileSplitterFetch.splitterStop(); |%ZJN{!R  
:3D6OBkB  
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} (Sgsy^|N  
} tD}-&"REP  
//负责部分文件的抓取 0!ZaR6  
**FileSplitterFetch.java `O0Qtq.  
*/ c^pQitPv  
package NetFox; "Ueq  
9*K-d'm  
a@|H6:|  
import java.io.*; ob2_=hQnC  
import java.net.*; 6D2ot&5WW  
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public class FileSplitterFetch extends Thread { 2YY4 XHQS  
qpCaW0]7  
EsX(<bx  
String sURL; //File URL \#) YS  
long nStartPos; //File Snippet Start Position =p=/@FN  
long nEndPos; //File Snippet End Position :A @f[Y'9  
int nThreadID; //Thread's ID )[ZXPD  
boolean bDownOver = false; //Downing is over T$R#d&t  
boolean bStop = false; //Stop identical `L7^f!  
FileAccessI fileAccessI = null; //File Access interface f+s)A(?3  
#V]8FW  
|gu@b~8  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _b-g^#L%  
{ Qb>("j~Z  
this.sURL = sURL; c_+fA  
this.nStartPos = nStart; 3%GsTq2o  
this.nEndPos = nEnd; $|J+  
nThreadID = id; 7 L,`7k|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7#G!es  
} MaY_*[  
0uW)&>W  
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public void run() +}?%w|8||s  
{ *C+[I  
while(nStartPos < nEndPos && !bStop) ?Sa,n^b*H  
{ J(/J;PW  
+6jGU'}[  
q. Jx|x  
try{ Ij.mLO]  
URL url = new URL(sURL); IZLCwaW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K39I j_3  
httpConnection.setRequestProperty("User-Agent","NetFox"); /.!&d^  
String sProperty = "bytes="+nStartPos+"-"; >yP>]r+  
httpConnection.setRequestProperty("RANGE",sProperty); 9
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Utility.log(sProperty); 3gVU#T[[  
+2 oZML  
cl&?'` )  
InputStream input = httpConnection.getInputStream();  +@f  
//logResponseHead(httpConnection); _xi&%F/  
j#P4&  
OAW_c.)5D  
byte[] b = new byte[1024]; B]<N7NYn1  
int nRead; =FIZh}JD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) HDzeotD  
{ @jMo/kO/A  
nStartPos += fileAccessI.write(b,0,nRead); -X7x~x-  
//if(nThreadID == 1) uaKbqX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V(0Y   
} `RE>gX  
G9QvIXRi  
H*3u]Ebh  
Utility.log("Thread " + nThreadID + " is over!"); Q#ksf h!D  
bDownOver = true; DA>nYj-s  
//nPos = fileAccessI.write (b,0,nRead); piIzff  
} >d]-X]  
catch(Exception e){e.printStackTrace ();} -#/DK   
} ]:?S}DRG  
} $E^sA|KcT  
rDoMz3[w  
1EQ:@1  
//打印回应的头信息 Lk#)VGk:  
public void logResponseHead(HttpURLConnection con) PyHL`PZZ  
{ V/"RCqY4  
for(int i=1;;i++) ;Wk3>\nT-  
{ 6]<yR> '  
String header=con.getHeaderFieldKey(i); \eQPvkx2  
if(header!=null) Ph.RWy")  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); S[
/udA  
Utility.log(header+" : "+con.getHeaderField(header)); G"u4]!$/  
else US9aW)8  
break; tS3&&t  
} AT3H
HQD  
} DaHbOs_<  
}{:}K<  
/`aPV"$M  
public void splitterStop() ]|w~{X!b4  
{ 9fb"R"(M  
bStop = true; kasx4m]^  
} NB/ wJ3 F  
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} @y\M8C8  
u
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/* c_bIadE{  
**FileAccess.java "^@0zy@x  
*//文件访问(定位，写) >&N8Du*[  
package NetFox; ijWn,bj  
import java.io.*; `BHPjp>  
fqU*y 6]  
GKKf#r74  
public class FileAccessI implements Serializable{ sny
g  
2s@<k1EdPl  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 x5}Ru0Z  
RandomAccessFile oSavedFile; :X;'37o#q  
long nPos; vL7JzSU_  
/A;!g5Y  

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public FileAccessI() throws IOException 9n"
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{ W[Ro)  
this("",0); ?F9:rUyN  
} AA$-Lx(UJk  
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public FileAccessI(String sName,long nPos) throws IOException 2!b+}+:  
{ C. Hr  
oSavedFile = new RandomAccessFile(sName,"rw"); ga~C?H,K  
this.nPos = nPos; n`krK"Ii  
oSavedFile.seek(nPos); EnGVp<6R  
} EI*B(  
fE;<)tU  
|A#pG^  
public synchronized int write(byte[] b,int nStart,int nLen) \ueo^p]_?  
{ *94<rlh{"  
int n = -1; y
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try{ #,1Kum bG3  
oSavedFile.write(b,nStart,nLen); )8:Ltn%  
n = nLen; }0Qex=vkO  
} 3%G>TB  
catch(IOException e) l* =\0
  
{ ew#t4~hh  
e.printStackTrace (); Ap{p_~~
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} c_e2'K:  
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return n; ~5[#c27E9  
} m?]XNgT  
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} 'a`cK;X9F  
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v"VpE`
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/* ?32gug\i'}  
**SiteInfoBean.java d|!FI/  
*/ fD<9k  
package NetFox; 59;p|  
2 5DXJb^:  
;by`[)  
public class SiteInfoBean { b!C\J  
#"J8]3\F  
B8){  
private String sSiteURL; //Site's URL mhZ{}~  
private String sFilePath; //Saved File's Path 6;WfsG5  
private String sFileName; //Saved File's Name e5/f%4YX  
private int nSplitter; //Count of Splited Downloading File v803@9@  
F<K;tt  
1 !N+hf  
public SiteInfoBean() Id6H~;  
{//nSplitter的缺省值为5 5G!0Yy['  
//default value of nSplitter is 5 $]v=2j  
this("","","",5); 6'YT3=  
} 37OU  
w$Zi'+&*  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e[<vVe!  
{ @d&(*9Y  
sSiteURL= sURL; RLy(Wz3%
 
sFilePath = sPath; 7Gwn,&)  
sFileName = sName; ,sw
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this.nSplitter = nSpiltter; -BQoNEh  
&8p]yo2zO  
L
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} ~ _ ogeD  
52X[{  
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public String getSSiteURL() b#~K>  
{  |2<y  
return sSiteURL; Db:^Omwo  
} pco:]3BF6  
ltQo_k  
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public void setSSiteURL(String value) l k~Vv
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{ |7Dc7p"D  
sSiteURL = value; 55Pe&V1=  
} )RUx  
qQ&=Z`p!  
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public String getSFilePath() >m:;.vVY  
{ %C[#:>'+  
return sFilePath; 91f{qq=#J{  
} v2Ft=_*G|  
CvOji1  
kAV4V;ydh  
public void setSFilePath(String value) h(~@ nd{  
{ WswM5RN  
sFilePath = value; ZVX1@p  
} /Fr*k5I  
p>ba6BDJT  
ltWEA  
public String getSFileName() ?4`f@=}'K  
{ .8%&K0  
return sFileName; }HCt=W`  
} FOyANN'  
\sn wR  
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public void setSFileName(String value) 2%?Kc]JY9  
{ Lo<WK  
sFileName = value; uQ
hI)  
} 7_9^nDU  
ZGw6Bd_I  
i}L*PCP  
public int getNSplitter() <@S'vcO  
{ %zKTrsMZ  
return nSplitter; 01n7ua*XX  
} ~hxW3e  
|4C5;"Pc  
+Pc2`,pw|  
public void setNSplitter(int nCount) u0Bz]Ux/Q  
{ swz)gh-*  
nSplitter = nCount; F05]6NVv  
} &c^tJ-s  
} v8"Zru  
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/* r,<p#4(>_  
**Utility.java ;uho.)%N`F  
*/ B)x^S >  
package NetFox; v=_Ds<6n  
jL{k!V`s  
jA? 7>"|  
public class Utility { sis1Dh9:  
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public Utility() ~bqw!rz  
{ \Ez&?yb/  
qL?$u07<9'  
+V9(4la  
}
8
{ +KNqz  
YIs_.
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//线程睡眠 Gs>4/  
public static void sleep(int nSecond) @dn&M9Z  
{ OYfRtfE  
try{ ,T-xuNYC  
Thread.sleep(nSecond); mLV0J '  
} eF(oHn,  
catch(Exception e) w0O(>  
{ 3fUiYI|&7  
e.printStackTrace (); $T_>WUiK  
} ,b<m],p  
} )m Ii.  
\D-X _.v  
//日志 g'9~T8i& ^  
public static void log(String sMsg) ~wu\j][2  
{ mMT\"bb'  
System.err.println(sMsg); HOrXxxp1^  
} ^SbxClUfw!  
It]GlxM
X  
7e[&hea  
public static void log(int sMsg) z2jS(N?J1  
{ LlD=c  
System.err.println(sMsg); " eS-i@  
} NAO0b5-h  
} &w{z  
4m%Yc
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R ^"*ut  
/* TpYdIt9#>  
**TestMethod.java %r@:7/  
*/ z`YAOhD*h4  
package NetFox; 3x=NSe|f  
`69xR[f  
QrLXAK\5  
public class TestMethod { D7Ds*X`!l  
^[EXTBk@:  

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public TestMethod() lr[&*v?h  
{ ///xx/weblogic60b2_win.exe L>rW S-  
try{ FX+^S?x.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); XUK%O8N#9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^ lG^.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0Hr)h{!F"  
fileFetch.start(); LufZ,  
} XRn+6fn|  
catch(Exception e){e.printStackTrace ();} T_qh_L3  
nN(Q}bF  
Ws[d.El  
} t`0(5v  
,]=Qgn  
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public static void main(String[] args) 9-?kamA  
{ Rp.FG   
new TestMethod(); w&}UgtEm  
} LESF*rh=  
} fG /wU$B  
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