http断点续传简单实现（java)

/* cVHE}0Xd(  
**SiteFileFetch.java ]20"la5  
*/ P7k$^n  
package NetFox; k@";i4}A  
import java.io.*; gy
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import java.net.*; Ualq>J5-m-  
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public class SiteFileFetch extends Thread { h^_taAdS`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean t-4R7`A<  
long[] nStartPos; //开始位置 JJHvj=9'o  
long[] nEndPos; //结束位置 %Rsf6rJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =W
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long nFileLength; //文件长度 .iN*V|n  
boolean bFirst = true; //是否第一次取文件 J_[[BJ&}x  
boolean bStop = false; //停止标志 ]zq_gV8k  
File tmpFile; //文件下载的临时信息 Nj-rZ%&  
DataOutputStream output; //输出到文件的输出流 c.{&~  
Nb!6YY=Ez-  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;7n*PBUJJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException $t H.np  
{ UrcN?  
siteInfoBean = bean; PUZXmnB  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v{{2<,l  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hYUV9k:  
if(tmpFile.exists ()) ~B*\k^
t`  
{ vwH7/+  
bFirst = false; .q9|XDqQc  
read_nPos(); oJJk  
} 2SPFjpG8n  
else =O'%)Y&  
{ fYQi#0drn  
nStartPos = new long[bean.getNSplitter()]; i`nw"8  
nEndPos = new long[bean.getNSplitter()]; '/Cz{<,  
} Ce'2lo  
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} 8(/f!~  
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public void run() c)!s[oL  
{ S1= JdN  
//获得文件长度 fQ.>G+0I>  
//分割文件 jG(~9P7  
//实例FileSplitterFetch RGA*7  
//启动FileSplitterFetch线程 ApJf4D<V  
//等待子线程返回 xOyL2  
try{ P5xmLefng  
if(bFirst) Ww tQ>'R"  
{ XhD fI &  
nFileLength = getFileSize(); MirBJL  
if(nFileLength == -1) 8Gg/M%wq9U  
{ |21hY  
System.err.println("File Length is not known!"); RowiSW  
} g7LW?Ewr  
else if(nFileLength == -2) ^?]H$e  
{ LP-Q'vb<=  
System.err.println("File is not access!"); z(X6%p0  
} _%Ld Ez  
else J9=0?^v-:B  
{ :aqskeT  
for(int i=0;i<nStartPos.length;i++) EM w(%}8w  
{ })SdaZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); X|1YGZJ  
} !K~$-jlT  
for(int i=0;i<nEndPos.length-1;i++) @d^h/w  
{ gI5nWEM0{  
nEndPos = nStartPos[i+1]; "3oU (RA  
} 7-IeJ6,D  
nEndPos[nEndPos.length-1] = nFileLength; C$ `Y[w  
} 3 DHA^9<q  
} N_Ld,J%g  
OwIy(ukTI  
9Zsb1 M!n>  
//启动子线程 8si^HEQ8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~[y+B0I3  
for(int i=0;i<nStartPos.length;i++) rPpAg  
{ ({nSs5)$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;OJ0}\*iP8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), swq!Sp  
nStartPos,nEndPos,i); fToI,FA
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5t?2B]  
fileSplitterFetch.start(); VX[!Vh  
} X@q1;J  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Lbp6I0&n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l4reG:uYG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xi. KD
 
nEndPos = " + nFileLength); X3O$Sd(D  
// fileSplitterFetch[nPos.length-1].start(); Z2jb>%  
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5@%-=87S  
//等待子线程结束 5m?$\h  
//int count = 0; j:KQIwc
 
//是否结束while循环 }/0dfes  
boolean breakWhile = false;
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~RAH -]  
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while(!bStop) r+pjv_R  
{ NT/B4'_@  
write_nPos(); swL|Ff`$  
Utility.sleep(500); k\%v;3nBK  
breakWhile = true; <uwCP4E  
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for(int i=0;i<nStartPos.length;i++) ea>\.D-S  
{ B&N&eRAE  
if(!fileSplitterFetch.bDownOver) Z`c{LYP,y"  
{ #de^~  
breakWhile = false; -Ep6.v  
break; {~I_rlo n  
} }3y\cv0ct  
} 8mLU ~P |  
if(breakWhile) 4PM`hc  
break; q#3X*!)  
:?k=Yr  
mJR T+SZ  
//count++; #'h CohL  
//if(count>4) iRHQRdij  
// siteStop(); R_n-&d'PP  
} U/o}{,$A  
Nb/%>3O@  
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System.err.println("文件下载结束！"); :ygz/L  
} !T. @  
catch(Exception e){e.printStackTrace ();} vGT.(:\-,  
} kk+8NwM1  
7"i*J6y*  
a`Zf_;$@  
//获得文件长度 toJ&$HrE  
public long getFileSize() Pv.@Y30  
{ ved Qwzh  
int nFileLength = -1; 0M+tKFb  
try{ ~"Ki2'j)^]  
URL url = new URL(siteInfoBean.getSSiteURL()); uwA3!5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TN`:T.B  
httpConnection.setRequestProperty("User-Agent","NetFox"); yo?Q%w'Nh  
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int responseCode=httpConnection.getResponseCode(); E/']M~Q  
if(responseCode>=400) 6J+ZeBk??  
{ 9(j!#`O7&  
processErrorCode(responseCode); 6E]rxps}"  
return -2; //-2 represent access is error zAUfd[g  
} TeqsP1{?  
j~q`xv+
R  
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String sHeader; {2@96o2}  
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q:.BY}X9  
for(int i=1;;i++) LWV`xCr8R  
{ -;"l5oX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J[wXG6M  
//Utility.log(in.readLine()); 1_lL?S3,a@  
sHeader=httpConnection.getHeaderFieldKey(i); w,9F riW  
if(sHeader!=null) 3vU (4}@  
{ P$I\)Q H  
if(sHeader.equals("Content-Length")) =C)1NJx&~  
{ HCK4h DKo}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); OhEL9"\<  
break; -m/4\D  
} qDAjW)w Jp  
} '7s!NF2  
else Dm#k-y  
break; Shz;)0To  
} P7-3Vf_L  
} IhLfuyFWu  
catch(IOException e){e.printStackTrace ();} 0aWb s$FyU  
catch(Exception e){e.printStackTrace ();} C<>.*wlp=  
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Utility.log(nFileLength); %A3Jd4DH  
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return nFileLength; oVW?d]R  
} mM.&c5U  
p;Kr664  
qE{S'XyM,  
//保存下载信息（文件指针位置） ]XU#i#;c  
private void write_nPos() 'zK*?= ^jk  
{ i;Y^}2   
try{ n TG|Isa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sSUd;BYf  
output.writeInt(nStartPos.length); aDuanGC/V  
for(int i=0;i<nStartPos.length;i++) B!@0(A  
{ "#jKk6{I0  
// output.writeLong(nPos); N=9lA0y+  
output.writeLong(fileSplitterFetch.nStartPos); Cq~Ir*"  
output.writeLong(fileSplitterFetch.nEndPos); I]X<L2  
} kZQ;\QL1}  
output.close(); UhK,H   
} e{&gF1"[  
catch(IOException e){e.printStackTrace ();} 3yN1cd"#?  
catch(Exception e){e.printStackTrace ();} BL67sva;  
} 51x,[y+Xe  
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//读取保存的下载信息（文件指针位置） RMK U5A7  
private void read_nPos()
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{ y1X.Mvc  
try{ ~_%[j8o&l  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); pG&.Ye]j  
int nCount = input.readInt(); "Q1hP9xV  
nStartPos = new long[nCount]; s3J$+1M>  
nEndPos = new long[nCount]; 0P(}e[~Z  
for(int i=0;i<nStartPos.length;i++) M_K&x-H0  
{ ]mSVjF3l  
nStartPos = input.readLong(); ?L^ Gu ]y  
nEndPos = input.readLong(); {Hu0  
} =%LS9e^7D  
input.close(); Gj=il-Po  
} Ry C7  
catch(IOException e){e.printStackTrace ();} 8@-US ,|  
catch(Exception e){e.printStackTrace ();} A7H=#L+C  
} R9(
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private void processErrorCode(int nErrorCode) ;q
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{ K#jm6Xh?E  
System.err.println("Error Code : " + nErrorCode); I/g]9 y  
} 6F2}|c  
rQJoaP+\q  
RMXP)[  
//停止文件下载 ^d,d<Uc  
public void siteStop() 6]VTn-  
{ v|6fqG+Q\  
bStop = true; y@I"Hk<T  
for(int i=0;i<nStartPos.length;i++) pN[i%\vh  
fileSplitterFetch.splitterStop(); VMp6s%m  
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} ''G@n*  
} ^s5)FdF8  
//负责部分文件的抓取 D$\ EZ
 
**FileSplitterFetch.java $3>|RlxYA  
*/ \;}dSSB1  
package NetFox; "TPMSx&Ei  
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import java.io.*; OR3TRa XD  
import java.net.*; u|e2T@t=  
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public class FileSplitterFetch extends Thread { W8)GT`\  
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_>s.V`N'  
String sURL; //File URL eX\t]{\oC  
long nStartPos; //File Snippet Start Position #ed]zI9O  
long nEndPos; //File Snippet End Position 6*$N@>8&  
int nThreadID; //Thread's ID y^ohns5{  
boolean bDownOver = false; //Downing is over AWw'pgTQX  
boolean bStop = false; //Stop identical )jg3`I@  
FileAccessI fileAccessI = null; //File Access interface ,~v1NK*  
?G@%haqn6  
;Bm{_$hf=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException IcB>Hg5  
{ \a<E3 <  
this.sURL = sURL; AK[c!mzx  
this.nStartPos = nStart; 52
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this.nEndPos = nEnd; <iMLM<J<w  
nThreadID = id; .fgoEB,(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @Z)&
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} T"O!  
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public void run() @_;6L  
{ uaiG(O   
while(nStartPos < nEndPos && !bStop) PqfH}d0l  
{ pcE.  
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try{ `| fF)kI  
URL url = new URL(sURL); FkH4|}1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xaPTTa  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1*XqwBV  
String sProperty = "bytes="+nStartPos+"-"; H]cCyuCdH  
httpConnection.setRequestProperty("RANGE",sProperty); Ou/{PK}  
Utility.log(sProperty); i+OyBDkJM!  
Q?~l=}2  
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InputStream input = httpConnection.getInputStream(); W*P/~U=  
//logResponseHead(httpConnection); ,\VNs'j  
#]9yzyb_y  
.NjOaK)\  
byte[] b = new byte[1024];  '{),gV.  
int nRead; Xs4`bbap  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -50|r;a  
{ .69{GM?  
nStartPos += fileAccessI.write(b,0,nRead); &`@K/Nf$9  
//if(nThreadID == 1) 44!bwXz8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8ED6C"6  
} V4|p
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oC[$PPqX#  
'Ic
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Utility.log("Thread " + nThreadID + " is over!"); 'C(YUlT2?P  
bDownOver = true; X4jtti  
//nPos = fileAccessI.write (b,0,nRead); !y6 D+<k*]  
} Rt+s\MC^r  
catch(Exception e){e.printStackTrace ();} <=WQs2  
} )AnX[:y  
} lE4.O  
Y#KgaZ7N  
i),W1<A1  
//打印回应的头信息 < d?O#(  
public void logResponseHead(HttpURLConnection con) UtzW5{  
{ nM@
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for(int i=1;;i++) w9vqFtj  
{ [-Dx)N  
String header=con.getHeaderFieldKey(i); $cc]pJy"}  
if(header!=null) QHK$2xtq|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y:xZ(RgfF  
Utility.log(header+" : "+con.getHeaderField(header)); l2xM.v
R  
else *f1MgP*GKF  
break; tip\vS)  
} J@52<.>6  
} -FwOX~s/'  
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public void splitterStop() NT:p6(s^  
{
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bStop = true; DvU(rr\p  
} ^MuO;<<,.  
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} >-f`mT  
k\A8Z[  
]"^U  
/* -Zkl\A$>  
**FileAccess.java G >bQlZG  
*//文件访问(定位，写) LXrnAt  
package NetFox; JW (.,Ztm  
import java.io.*; +Ibcc8Qud  
L9"V$MO  
Yz4Q!tL  
public class FileAccessI implements Serializable{ FgLV>#)-  
2]hQ56Yv3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 525W; mu{  
RandomAccessFile oSavedFile; Jc
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long nPos; {U>B\D  
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public FileAccessI() throws IOException l@%MS\{  
{ |X0h-kX4  
this("",0); UO>ADRs}  
} m!V ?xGKJ  
d[J
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public FileAccessI(String sName,long nPos) throws IOException >T=($:n  
{ CtfI&rb[  
oSavedFile = new RandomAccessFile(sName,"rw"); #3leMZ6  
this.nPos = nPos; Z+x,Awq  
oSavedFile.seek(nPos); o[X'We;  
} 2eK!<Gj  
z1K@AaRx  
f%;8]a9  
public synchronized int write(byte[] b,int nStart,int nLen) u,I_p[`E  
{ 0"#'Z>"  
int n = -1; _SY4Qs`d  
try{ +iY.YV  
oSavedFile.write(b,nStart,nLen); R.-2shOE'  
n = nLen; @lRT
p  
}
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catch(IOException e) %We~k'2f  
{ cia'h_w  
e.printStackTrace (); 9Ra*bP ]1  
} EBc_RpC/Z  
V4PI~"4q#1  
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return n; 4$ya$Y%s%  
} Js.2R$o =*  
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} qj/ pd 7\  
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/* DryN}EMOKD  
**SiteInfoBean.java MEf`&<t  
*/ M{w[hV  
package NetFox; >+ZBQ]~  
FxeDjAP  
e)"]H*  
public class SiteInfoBean { Q8OA{EUtq  
l];w,(u{  
q$x$ 4  
private String sSiteURL; //Site's URL ,rc?,J1l  
private String sFilePath; //Saved File's Path o."k7fLB  
private String sFileName; //Saved File's Name >>22:JI`  
private int nSplitter; //Count of Splited Downloading File M$iDaEu-  
B)>r~v]  
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public SiteInfoBean() Q$u&/g3NvL  
{//nSplitter的缺省值为5 mCah{~  
//default value of nSplitter is 5 O|wu;1pQ  
this("","","",5); 5P'o+Vwz  
} q% *-4GP  
>ka*-8?  
~QzUQYG*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nK[T.?Nz  
{ jd ]$U_U(  
sSiteURL= sURL; J'{69<`Dl  
sFilePath = sPath; |[qq $  
sFileName = sName; Z1Y/2MVSb  
this.nSplitter = nSpiltter; {E
U?{#  
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jT/}5\  
} }(tuBJ9  
nwSujD  
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public String getSSiteURL() " ,k(*  
{ G4O $gg  
return sSiteURL; B6qM0QW  
} dAg<BK/  
o\<m99Ub  
::?,ZA  
public void setSSiteURL(String value) I!LSDi3  
{ S=NP}4w,_)  
sSiteURL = value; /L|$* Xj  
} _%M+!Ltz  
p=13tQS<  
^<u9I5?  
public String getSFilePath() p>x[:*  
{ (h&XtFul}  
return sFilePath; #WE"nh9f|z  
} 8d4:8}
  
%*:X FB  
+ftOJFkI  
public void setSFilePath(String value) -!_\4
 
{ 1=o|[
7  
sFilePath = value; `wGP31Y.  
} ,^Ug[pGG-  
Q#gzk%jL@  
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public String getSFileName() &ZyZmB  
{ `3wzOMgJ  
return sFileName; t?&@bs5~g  
} Xgb ~ED]  
sWtT"7>x  
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public void setSFileName(String value) /i!3Fr"  
{ U
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sFileName = value; J)kH$!csi  
} yLFZo"r  
$RASpM  
$nf5bo/;  
public int getNSplitter() g#W/WKvM  
{ 8,VX%CS#q  
return nSplitter; xJcM1>cT>  
} yiT)m]E d  
N*mm[F2+F  

&PE/\_xD_  
public void setNSplitter(int nCount) 85{2TXQ^%=  
{ Nd;)V  
nSplitter = nCount; lhk=yVG3  
} 8?yRa{'"  
} xbTvv>'U  
Bme_#  
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/* OCX>LK!K  
**Utility.java YZ0y_it)  
*/ \Ei(HmEU  
package NetFox; bY@ S[  
;~^9$Z@%Q  
JkfVsmc<{h  
public class Utility { n7A %y2  
'nx";[6(  
Q|$?d4La8  
public Utility() ?=^~(x?S  
{ %@q/OVnM  
31cC*  
F]qX}  
} #&$a7L}  
Q$`u=-h|  
//线程睡眠 \gU=B|W  
public static void sleep(int nSecond) s3Wjg  
{ 2SABu796j  
try{ s:p6oEQ=J  
Thread.sleep(nSecond); kO)+%'L!8  
} M9PzA'}4W6  
catch(Exception e) Id(wY$C&>  
{ HNMVs]/e  
e.printStackTrace (); P&g.%8b~84  
} n1E^8[~'  
} r.~^h^c]  
L/+KY_b:*  
//日志 s7 K](T4  
public static void log(String sMsg) q8=hUD%5C  
{ #Rw9Iy4  
System.err.println(sMsg); ^.Xom~  
} PV(TDb:0  
'F .tOD  
@lO(QpdG  
public static void log(int sMsg) cUDo}Yu  
{ rzk-_AFR  
System.err.println(sMsg); {y
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} _=g;K+%fb  
} #"PRsMUw  
=QG0:z)K<v  
{=Y3[  
/* 'P`L?/_3  
**TestMethod.java wI{ED  
*/
6@X j  
package NetFox; O_~vl m<#  
C)H1<Br7  
+\D?H.P  
public class TestMethod { $LXz Q>w9  
BIK^<_?+ZU  
;zpSyyp@  
public TestMethod() 13f@Ox$  
{ ///xx/weblogic60b2_win.exe _?m%i]~o
 
try{ 7[/1uI9U8K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7j//x Tr}a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -ge :y2R_w  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Xlp$xp"  
fileFetch.start(); jn:9Cr,o;g  
} qiyX{J7Z  
catch(Exception e){e.printStackTrace ();} OtsW>L@ O(  
FHv^^
u'@  
P_y8[Y]?  
} "4Bk  
Y5&mJp\G  
o)U4RY*  
public static void main(String[] args) H6Dw5vG"l  
{ ]N#%exBVo  
new TestMethod(); 4xl}kmvv  
} jjTb:Z=.'  
} q"OJF'>w5  
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