http断点续传简单实现（java)

/* 9{-EJ)  
**SiteFileFetch.java IIg^FZ*]_  
*/ qp/v^$EA  
package NetFox; ~MS\  
import java.io.*;  '`eO\huf  
import java.net.*; I2 j}Am  
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public class SiteFileFetch extends Thread { D[^m{ 9_  
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SiteInfoBean siteInfoBean = null; //文件信息Bean BlXB7q,  
long[] nStartPos; //开始位置 !OBEM1~ 1  
long[] nEndPos; //结束位置 >iD )eB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u#Z#)3P  
long nFileLength; //文件长度 zY,r9<I8_x  
boolean bFirst = true; //是否第一次取文件 p /#$io  
boolean bStop = false; //停止标志 ^zt-HDBR_  
File tmpFile; //文件下载的临时信息 m\$\ 09  
DataOutputStream output; //输出到文件的输出流 .Jt[(;  
R$[#+X!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uM_#  
public SiteFileFetch(SiteInfoBean bean) throws IOException }"=AG  
{ DTaN"{  
siteInfoBean = bean; !R1.7}O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7qj9&bEy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); s}jHl8  
if(tmpFile.exists ()) F'B8v3  
{ J]&y$?C  
bFirst = false; 4F{)i  
read_nPos(); fcNL$U&-,i  
} .2>p3|F  
else >p.O0G gg  
{ uoHNn7W  
nStartPos = new long[bean.getNSplitter()]; %,D<O,N  
nEndPos = new long[bean.getNSplitter()]; &jsVw)Ue  
} 7PANtCFb&  
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} dl~%MWAVb  
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public void run() A8pIs  
{ {_S}H1,  
//获得文件长度 5m9*85Ib  
//分割文件 {@tv>!WW  
//实例FileSplitterFetch 4?-.ZUT-1  
//启动FileSplitterFetch线程 qEpi]=|  
//等待子线程返回 1jc, Y.mP  
try{ yqi^>Ce0  
if(bFirst) "FTfk  
{ yil[gPy4B  
nFileLength = getFileSize(); _T2=J+"-Kp  
if(nFileLength == -1) \T<$9aNb  
{ 2I&o69x?  
System.err.println("File Length is not known!"); >y[oP!-|P  
}  ^}:#  
else if(nFileLength == -2) 3'^k$;^  
{ 6xZ=^;H  
System.err.println("File is not access!"); tQH+)*  
} %*&UJpbA  
else o>7ts&rk  
{ iK12pw  
for(int i=0;i<nStartPos.length;i++) S(uf(q|{  
{ #m[|2R  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gFHTG  
} ,4ei2`wV  
for(int i=0;i<nEndPos.length-1;i++) s
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{ L2, 1Kt7  
nEndPos = nStartPos[i+1]; z.Y$7bf)  
} d)pV;6%[$q  
nEndPos[nEndPos.length-1] = nFileLength; QF&W`c  
} r=6v`)Qr  
} /)dFK~  
>2]JXLq  
'A:x/iv}^  
//启动子线程 %K>.lh@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [o.B  
for(int i=0;i<nStartPos.length;i++) 3bDQk :L  
{ Fd#m<"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oI.G-ChP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l'\pk<V  
nStartPos,nEndPos,i); :dLAs@z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cIp D~0\  
fileSplitterFetch.start(); /r-aPJX  
} `&-
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8Goh4T H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3"G>>nC&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  8HRmQ  
nEndPos = " + nFileLength); e0J6Ae4V[  
// fileSplitterFetch[nPos.length-1].start(); z,VD=Hnz  
jK' N((Hz  
^D<r  
//等待子线程结束 Ur5FC r  
//int count = 0;  +QE^\a  
//是否结束while循环 1.gG^$Jd  
boolean breakWhile = false; +
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G 2mX;  
glDh([  
while(!bStop) MW PvR|Q  
{ T}4/0yR2  
write_nPos(); F35#dIs`&  
Utility.sleep(500); 2^)1N>"g  
breakWhile = true; ZeEWp3vW  
^;Sy. W&`  
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for(int i=0;i<nStartPos.length;i++) vmLxkjUm#  
{ H6&J;yT}  
if(!fileSplitterFetch.bDownOver) 5ux`U{`m  
{ me'd6!O9-  
breakWhile = false; x3u4v~ "-  
break; cZ<A0  
} KX}Rr
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} 8P"_#M?!  
if(breakWhile) h68]=KyK  
break; -CRQ&#p1]  
gq"gUaz  
Y;)dct  
//count++; Dc+'<"  
//if(count>4) <a[Yk 2
 
// siteStop(); =&},;VOh  
} 4T?h  
sYdRh?Hq  
|=EZ1<KzD  
System.err.println("文件下载结束！"); {O+Kw<d  
} JMVNmq&0  
catch(Exception e){e.printStackTrace ();} NHl|x4Zpw  
} =b[_@zq]  
o}<4*qlI  
!xwG%{_  
//获得文件长度 ]XTu+T.aT  
public long getFileSize() Z(9u<  
{ !o>H1#2l  
int nFileLength = -1; e5OsIVtjr  
try{ HFqm6|  
URL url = new URL(siteInfoBean.getSSiteURL()); 4&HXkRs:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \T;\XAGr  
httpConnection.setRequestProperty("User-Agent","NetFox"); H
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b]7GmRekl  
/RyR>G!  
int responseCode=httpConnection.getResponseCode(); ?h0X,fl3  
if(responseCode>=400) $-&BB(-{E&  
{ #
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processErrorCode(responseCode); [y0O{,lI  
return -2; //-2 represent access is error HBY.DCN[Z  
} 2QNNp:`6  
MgC:b-&5_  
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String sHeader; k64."*X  
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for(int i=1;;i++)
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{ 2jbIW*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); af|5n><~A  
//Utility.log(in.readLine()); x)UwV  
sHeader=httpConnection.getHeaderFieldKey(i); l?iSxqdT  
if(sHeader!=null) a,o_`s<  
{ ;r/;m\V  
if(sHeader.equals("Content-Length")) up2+s#  
{ U#n#7G6fRp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z`6fotL  
break; CdUAy|!`R  
} 
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} J>^\oAgpE  
else |ea~'N1  
break; &vovA} F  
} 2S8P}$mM  
} m'-|{c  
catch(IOException e){e.printStackTrace ();} \]9.zlB  
catch(Exception e){e.printStackTrace ();} X1tXqHJF}  
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u4"SH(  
Utility.log(nFileLength); }YOL"<,:o  
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return nFileLength; 7DKz;o  
} 3u>8\|8wz  
dJ:MjQG`W  
\#'TNmS  
//保存下载信息（文件指针位置） ^Cv^yTj;&  
private void write_nPos() q@hp.(V  
{ >O/D!j|  
try{ !'=15&5@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }<jb vCeK  
output.writeInt(nStartPos.length); mfny4R
1_  
for(int i=0;i<nStartPos.length;i++) -;;Z 'NM;8  
{ i{^Z1;Yl  
// output.writeLong(nPos); ^O^:$nXhYy  
output.writeLong(fileSplitterFetch.nStartPos); h5kPn~  
output.writeLong(fileSplitterFetch.nEndPos); /$"[k2 N  
}
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output.close(); O;HY%  
} GO! uwo:  
catch(IOException e){e.printStackTrace ();} fWGOP~0  
catch(Exception e){e.printStackTrace ();} 3E^M?N2oc  
} T88Y qI  
QIB>rQCceo  
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//读取保存的下载信息（文件指针位置） 6O2=Ns;J6  
private void read_nPos() Q6C-4ja  
{ 5~XN>>hp  
try{ ":Edu,6O  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Lh$dzHq  
int nCount = input.readInt(); ~Z$bf>[(R7  
nStartPos = new long[nCount]; rSP_:}  
nEndPos = new long[nCount]; ?RFg$Z'^  
for(int i=0;i<nStartPos.length;i++) K:y^OAZfV  
{ :RxHw;!  
nStartPos = input.readLong(); 3}1ss
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nEndPos = input.readLong(); 1on'^8]0  
} 4y
}"Hy  
input.close(); (/" &  
} ?v}Bd!'+P  
catch(IOException e){e.printStackTrace ();} '[P}&<ie,  
catch(Exception e){e.printStackTrace ();} P ,eH5w"  
} 3UUGblg`~  
L3(^{W]|  
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private void processErrorCode(int nErrorCode) Z
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{ ?lCd{14Mkh  
System.err.println("Error Code : " + nErrorCode); N?4q  
} RAs0]K  
io4A>>W==/  
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//停止文件下载 Fs/?  
public void siteStop() Ix
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{ zGcqzYbuA  
bStop = true; CPazEe1S  
for(int i=0;i<nStartPos.length;i++) O';ew)tI  
fileSplitterFetch.splitterStop(); )wzV $(~  
7q9gngT1LA  
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} dpN@#w  
} }b["Jk\2  
//负责部分文件的抓取 x4a:PuqmGG  
**FileSplitterFetch.java 6er(%4!  
*/ )E7 FA|  
package NetFox; T9y;OG  
ZX`J8lZP  
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import java.io.*; yfjXqn[Z4  
import java.net.*; iy
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public class FileSplitterFetch extends Thread { t]_S  
6a}r( yP  
ySN
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String sURL; //File URL DhKr;e  
long nStartPos; //File Snippet Start Position rE!1wc>L  
long nEndPos; //File Snippet End Position &bC}3D  
int nThreadID; //Thread's ID sJr5t?  
boolean bDownOver = false; //Downing is over KAA3iA@>+  
boolean bStop = false; //Stop identical ^Ip3A  
FileAccessI fileAccessI = null; //File Access interface 3=4SGt5m  
1|y$~R.H  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?H;{~n?  
{ cHvF*A  
this.sURL = sURL; T.?k>Ak  
this.nStartPos = nStart; ( 76{2  
this.nEndPos = nEnd; - HOnB=  
nThreadID = id; j^u[F"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |DG@ht  
} ]gd/}m)1  
^3I'y UsY  
/r$&]C:Fi  
public void run()  ~Nh&.a  
{ 2g`[u|  
while(nStartPos < nEndPos && !bStop) ~5#)N{GbY  
{ ?s{C//  
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try{ KXBL eR&^  
URL url = new URL(sURL); R ZcH+?7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bcJ@-i0V  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8cr NOZS6  
String sProperty = "bytes="+nStartPos+"-"; x
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httpConnection.setRequestProperty("RANGE",sProperty); A]y*so!)>  
Utility.log(sProperty); ;( KMGir
 
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InputStream input = httpConnection.getInputStream(); hH4o;0rqJ  
//logResponseHead(httpConnection); Sni=gZK  
#3.)H9  
*%- ?54B  
byte[] b = new byte[1024]; @&R1wr1>I5  
int nRead; 1i?=JAFfM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1Kc^m\  
{ ,nE&Me&#J  
nStartPos += fileAccessI.write(b,0,nRead); (wL3 +  
//if(nThreadID == 1) W8/(;K`/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,Aa|Bd]b  
} Zq?_dIX %  
KRk~w]  
X ]s"5ju|t  
Utility.log("Thread " + nThreadID + " is over!"); ,t~sV@ap  
bDownOver = true; F3 f@9@b  
//nPos = fileAccessI.write (b,0,nRead); p?Sl}A@`  
} Zc\S$+PM  
catch(Exception e){e.printStackTrace ();} ,olwwv_8G  
} @\!!t{y  
} F.KrZ3%4iB  
{!K;`I[]v  
q) _r3   
//打印回应的头信息 ER<eX4oU  
public void logResponseHead(HttpURLConnection con) 6&],WGz  
{ 9s $PrF  
for(int i=1;;i++) ^![{,o@"A  
{
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String header=con.getHeaderFieldKey(i); GVObz?Z]SB  
if(header!=null) &:auB:b  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9t}xXk  
Utility.log(header+" : "+con.getHeaderField(header)); 3}4#I_<$F@  
else @&:VKpu\  
break; uX0 Bp8P  
} d^SE)/j  
} Qp69Sk@H{  
Y\8+}g;KR  
SKxe3  
public void splitterStop() /+P5)q TKL  
{ hO;9Y|y  
bStop = true; `@\^m_!}  
} {,v: GMsm  
C9Wojo.  
Ki 3_N*z  
} (w2(qT&O  
>ZDC . ~  
I=b'j5c  
/* <UK5eVQn  
**FileAccess.java Ld~4nc$H8  
*//文件访问(定位，写) pX]21&F  
package NetFox; >Fh#DmQ  
import java.io.*; [D9
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H /%}R  
[Pqn3I[  
public class FileAccessI implements Serializable{ Qg{WMlyOP  
FG _,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {9{J^
@@  
RandomAccessFile oSavedFile; $O]^Xm3{@  
long nPos; g 2#F_  
M\jB)@)  
%(NN*o9"q  
public FileAccessI() throws IOException dk4D+*R  
{ TPqvp|~2  
this("",0); aZxO/b^j  
} r$?Vx_f`Q  
i"fCpkAP  
;r=?BbND?  
public FileAccessI(String sName,long nPos) throws IOException f~v"zT  
{ b\M b*o  
oSavedFile = new RandomAccessFile(sName,"rw"); 3 9yz~  
this.nPos = nPos; VK$zq5D  
oSavedFile.seek(nPos); Nc
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} H CuK  
2@5A&b  
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public synchronized int write(byte[] b,int nStart,int nLen) 2moIgJ   
{ 5"e+& zU~f  
int n = -1; F%y{% C7l  
try{ QP<FCmt8  
oSavedFile.write(b,nStart,nLen); 6.UKB<sV  
n = nLen; 1::LN(`<  
} K /8qB~J*  
catch(IOException e) J2=*-O:  
{ /6smVz@O  
e.printStackTrace (); A{t"M-<  
} Fi/jR0]e2  
[{/$9k-aF?  
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return n; 79a9L{gso  
} n8Q* _?Z/  
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} ,.q8Xf  
[Q=4P*G}X  
Bjtj{B  
/* CJ:uYXJJ:z  
**SiteInfoBean.java 67fIIXk&  
*/ 2
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package NetFox; -2z,cj&E{  
"C& Jwm?  
9G+y.^/6  
public class SiteInfoBean { z=[l.Af_  
"TUPYFK9  
|C|:i@c H  
private String sSiteURL; //Site's URL a/QIJ*0  
private String sFilePath; //Saved File's Path `{%-*f^  
private String sFileName; //Saved File's Name h2AGEg'g2[  
private int nSplitter; //Count of Splited Downloading File 2>ys2:z  
#*\
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qZ233pc  
public SiteInfoBean() vD_u[j]  
{//nSplitter的缺省值为5 u9 %;{:]h  
//default value of nSplitter is 5 3m3 EXz  
this("","","",5); MHGjvSx  
} 2S'AIuIew
 
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va@XbUC  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?${V{=)*X'  
{ 3L*+8a  
sSiteURL= sURL; \
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sFilePath = sPath; J/L)3y
 
sFileName = sName; +&(J
n  
this.nSplitter = nSpiltter; <Ak:8&$O  
6(,ItMbI  
iY}QgB< M  
} |^>u<E5  
IC\E,m  
V;P1nL4L  
public String getSSiteURL() "Jf4N  
{  .fbYB,0w  
return sSiteURL; l'W3=,G[?  
} f>|9 l  
j`{fB}  
)Kxs@F  
public void setSSiteURL(String value) j1W bD7*8  
{ 33O)k*g  
sSiteURL = value; @Ap@m6K?q  
} +yt6.L  
7xz#D4[  
|}:e+?{o  
public String getSFilePath() yY'gx|\  
{ pb~Ps#"Zg  
return sFilePath; PkjT&e)  
} -6(h@F%E  
5sG ]3z+1  
]aREQ?ma&z  
public void setSFilePath(String value) *X%?3"WH8  
{ sV]i/B  
sFilePath = value; @wg&6uQ  
} Y"r3i]  
58qaA\iw  
o-L|"3P  
public String getSFileName() ^ b=5 6~[  
{ EPQ&?[6  
return sFileName; M4R%Gr,La  
} M0Lon/%  
b(g_.1[  
Ar\IZ_Q  
public void setSFileName(String value) >+zAWK9  
{ U+:S7z@j?  
sFileName = value; u!hq
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} Bidqf7v  
6(\q< fx  
1!K!oY  
public int getNSplitter() [3Wsc`Q  
{ K!pxDW}  
return nSplitter; ~vO'p  
} ZJ;wRd@  
-HO6K)ur  
L%TxP6z4A  
public void setNSplitter(int nCount) pyu46iE)  
{ se4w~\/  
nSplitter = nCount; F! |TW6)gv  
} I|Vk.,  
} ?FkQe~FN{  
N:m@D][/sW  
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/* ,e}mR>i=e  
**Utility.java *?EjYI  
*/ fx8y`8}_  
package NetFox; ZE5-i@1  
2<`gs(oxXe  
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public class Utility { : OSmr  
Dx9$H++6$X  
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public Utility() 3C E 39W  
{ F]dmc,Q  
UXcH";*9b  
>[A65q'  
} Om&{4a\  
dVY(V&p  
//线程睡眠 Q' OuZKhA  
public static void sleep(int nSecond) p,_6jdz  
{ T%N~oa  
try{ \@iOnRuHn9  
Thread.sleep(nSecond); [|c@Yw  
} j]cXLY  
catch(Exception e) A8A:@-e8A  
{ KT]J,b  
e.printStackTrace (); F$"MFdc[  
} '<*CD_2t-  
} .:#_5K  
C[Y%=\6'0  
//日志 \4]zNV ~x  
public static void log(String sMsg) &r5&6p  
{ /)eNx  
System.err.println(sMsg); WF3DGqs_]  
} SNopAACf1  
v
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(50[,:#  
public static void log(int sMsg) /ej/&x15  
{ URmAI8fq*M  
System.err.println(sMsg); mE3SiR "  
} O>tC]sm%  
} gKm@B{rC  
U_N5~#9  
5<:VJC<  
/* ? bUpK  
**TestMethod.java ]%WD} 4e  
*/ ]ft~OqLg!  
package NetFox; E'Fv *UA  
N4Fy8qU;  
ci{9ODN  
public class TestMethod { FBwncG$]F*  
;?O883@r8  
xqi*N13  
public TestMethod() ]IbPWBX  
{ ///xx/weblogic60b2_win.exe r=iMo7q  
try{ Npf7p  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %Mb( c+7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); y.ivz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &?5{z
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fileFetch.start(); 6S&

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} 9wDBC~.  
catch(Exception e){e.printStackTrace ();} u]>>B>KOJ7  
c],frhmyd  
67KRM(S  
} 9$\;voo  
Gn2bZ%l  
Ma*dIwEp
 
public static void main(String[] args) _L `N^I.  
{ [Q.4]K2  
new TestMethod(); a|6x!p2X  
} c|!A?>O?i  
} zv
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