http断点续传简单实现（java)

/* ^$X|Lq  
**SiteFileFetch.java Z1Qv>@u  
*/ vCXmu_S4^>  
package NetFox; nM ?Nf}  
import java.io.*; @|5B}%!  
import java.net.*; ns*:mGh  
/='Q-`?9  
w!z*?k=Da  
public class SiteFileFetch extends Thread { ?rA3<j  
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{> <1K6t  
SiteInfoBean siteInfoBean = null; //文件信息Bean ANJL8t-m  
long[] nStartPos; //开始位置 t\}_WygN  
long[] nEndPos; //结束位置 t{QQ;'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 s;..a&C'  
long nFileLength; //文件长度 ~9xkiu5~  
boolean bFirst = true; //是否第一次取文件 xcn~KF8  
boolean bStop = false; //停止标志 !dUdz7  
File tmpFile; //文件下载的临时信息 &]GR
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DataOutputStream output; //输出到文件的输出流 a 9{:ot8,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5423Ky<
 
public SiteFileFetch(SiteInfoBean bean) throws IOException Xs# _AX  
{ <h;_:  
siteInfoBean = bean; 3l,-n|x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); QnP?j&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .ZV='i()X  
if(tmpFile.exists ()) p2k`)=iX  
{ Qc)i?Z'6  
bFirst = false; Kn<+Au_]L  
read_nPos(); ck%YEMs  
} TOF V`7q;3  
else B
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{ e9 @{[  
nStartPos = new long[bean.getNSplitter()]; !>D[Y  
nEndPos = new long[bean.getNSplitter()]; /}J_2  
} 8|<</v8i  
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} rfYa<M Qc  
B :S8{  
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public void run() ;6D3>Lm  
{ ~*"ZF-c
,  
//获得文件长度 :o8|P  
//分割文件 ]jC{o,?s  
//实例FileSplitterFetch <
#4""FO*  
//启动FileSplitterFetch线程 1#%H!GKvTU  
//等待子线程返回 </D.}ia  
try{ 2O*At%CzW  
if(bFirst) Q{?\qCrrYl  
{ LU+SuVm  
nFileLength = getFileSize(); \#LDX,=  
if(nFileLength == -1) tgl(*[T2  
{ U;4i&=.!  
System.err.println("File Length is not known!"); /3Gq&[R{  
} J]XLWAM  
else if(nFileLength == -2) [5!}+8]W  
{ j6RV{Lkr_  
System.err.println("File is not access!"); IN<nZ?D#  
} S{N4[U?V>  
else wdfbl_`T  
{ d'ZB{'[8p  
for(int i=0;i<nStartPos.length;i++) Knqv|jJVx1  
{ R!QR@*N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); y0(.6HI  
} $[?N^   
for(int i=0;i<nEndPos.length-1;i++)  YTZ :D/  
{ |h6!bt!=  
nEndPos = nStartPos[i+1]; :wXiz`VH  
} `^[Tu 1  
nEndPos[nEndPos.length-1] = nFileLength; Md@x2
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} k{#k:  
} ][tR=Y#&y5  
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//启动子线程 I&#:/|{:5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *EvW: <  
for(int i=0;i<nStartPos.length;i++) ^h2+""  
{ 
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +aL
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |8~)3P k  
nStartPos,nEndPos,i); !J<Xel{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mz%
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fileSplitterFetch.start(); \V!{z;.fA  
} W)bSLD   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MnqT?Cc4$j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); aT IzfqCM  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Vm\zLWNB  
nEndPos = " + nFileLength); poW%Fzj  
// fileSplitterFetch[nPos.length-1].start(); r>ed/<_>m;  
Y)F(-H)  
X"d"a={]  
//等待子线程结束 qhvT,"  
//int count = 0; HM0&%  
//是否结束while循环 Q"u2<  
boolean breakWhile = false; yOQae m^O  
n@ba>m4{  
F7O*%y.';  
while(!bStop) -O?HfQ  
{ LH_H yP_  
write_nPos(); r'#!w3*Cy  
Utility.sleep(500); Be@g|'r  
breakWhile = true; rZpsC}C'  
}=R0AKz!Cv  
KCbJ^Rln  
for(int i=0;i<nStartPos.length;i++) Q&{C%j~N  
{ yp$jLBA  
if(!fileSplitterFetch.bDownOver) EGqu-WBS  
{ "Hz%0zP&  
breakWhile = false; [zN*P$U]  
break; tjRwbnT"  
} mxF+Fp~  
} 7glf?oE  
if(breakWhile) [<U=)!Swg  
break; N atC}k  
~!mY0odH  
ibZ[U p?  
//count++; _;5zA"~c#@  
//if(count>4) i0wBZ i?  
// siteStop(); @]#[TbNo  
} =>c0NT  
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System.err.println("文件下载结束！"); `lOW7Z}  
} BC_<1 c  
catch(Exception e){e.printStackTrace ();} "}1cQ|0a  
} |-{e!&  
hy;V~J#  
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//获得文件长度 3GKKC9C6  
public long getFileSize() \F`>zY2$%  
{ Q.eD:
@%iE  
int nFileLength = -1; H'udxPF  
try{ .!L{yU,  
URL url = new URL(siteInfoBean.getSSiteURL()); !:5'MI@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wd!Z
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httpConnection.setRequestProperty("User-Agent","NetFox"); _u6NaB  
q:M'|5P  
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int responseCode=httpConnection.getResponseCode(); TAOsg0  
if(responseCode>=400) x2&5zp  
{ BjPU@rS.U  
processErrorCode(responseCode); zi`q(
[  
return -2; //-2 represent access is error /^jl||'H,:  
} vs+aUT C\  
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h {Jio>  
String sHeader; J9tV|
0  
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for(int i=1;;i++) XPdqE`w=$p  
{ sl@>
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2{BS `f  
//Utility.log(in.readLine()); Dpu?JF]  
sHeader=httpConnection.getHeaderFieldKey(i); Iy;"ht6  
if(sHeader!=null) /3hY[#e  
{ c+z [4"rYL  
if(sHeader.equals("Content-Length")) fD\Fq'29{  
{ LDU4 D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); icIWv  
break; vN_ 8qzWk  
} kzK9.  
} A\9LJ#E  
else fyT|xI`iD  
break; b|E ZD3y  
} $.w$x1  
} ^jRX6  
catch(IOException e){e.printStackTrace ();} "Vl4=W)u  
catch(Exception e){e.printStackTrace ();} Z;1r=p#s  
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Utility.log(nFileLength); _4nm h0q4  
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return nFileLength; F(l
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} fdwP@6eh  
] `q]n  
QT!>izgcU  
//保存下载信息（文件指针位置） NMhpKno  
private void write_nPos() #rr!A
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{ ^\`a-l^  
try{ c1a

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output = new DataOutputStream(new FileOutputStream(tmpFile)); @VG@|BQWa  
output.writeInt(nStartPos.length); b]xoXC6@t  
for(int i=0;i<nStartPos.length;i++) H=~7g3  
{ o6~JAvw  
// output.writeLong(nPos); i0+e3!QU  
output.writeLong(fileSplitterFetch.nStartPos); HIE8@Rv/3  
output.writeLong(fileSplitterFetch.nEndPos); d8 Jf3Mo  
} 7hPwa3D^  
output.close(); ~G=E Q]a
  
} 0T(+
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catch(IOException e){e.printStackTrace ();} B@dCCKc%/  
catch(Exception e){e.printStackTrace ();} /|}yf/^9X  
} .GNyADQp  
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//读取保存的下载信息（文件指针位置） b.?;I7r   
private void read_nPos() kF,ME5%  
{ 6`7bk35B  
try{ Pn.DeoHme  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $$o(  
int nCount = input.readInt(); < Mu`,Kv*  
nStartPos = new long[nCount]; -
}!miV  
nEndPos = new long[nCount]; kFmtE dhsc  
for(int i=0;i<nStartPos.length;i++) ~&MDfpl  
{ %3t;[$n#  
nStartPos = input.readLong(); y`7<c5zD  
nEndPos = input.readLong(); bE2O[B  
} OA\]|2 :  
input.close(); 6~W@$SP,F  
} -oUNK}>  
catch(IOException e){e.printStackTrace ();} ~$[fG}C.K  
catch(Exception e){e.printStackTrace ();} 8c9<kGm$E  
} -+Yark  
1t?OD_d!8  
#Cu$y8~as  
private void processErrorCode(int nErrorCode) q<z8P;oP^  
{ 2?Jw0Wq5D  
System.err.println("Error Code : " + nErrorCode); Xfqin4/jC  
} m}RZ)c  
&$_!S!Sa/  
u "k< N|.3  
//停止文件下载 [Eu)~J*
 
public void siteStop() ZxT E(BQv  
{ X~"p]V_  
bStop = true; H7;,Kr  
for(int i=0;i<nStartPos.length;i++) $HQ4o\~  
fileSplitterFetch.splitterStop(); \ ya@9OA  
5.
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} ivq(eKy  
} l|gi2~ %Y  
//负责部分文件的抓取 ;i6~iLY  
**FileSplitterFetch.java >{Hg+
/  
*/ Hm'"I!jyO  
package NetFox; o6O-\d7
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import java.io.*; @y;VV*  
import java.net.*; \~,\|  
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public class FileSplitterFetch extends Thread { u)r/#fUZ  
JnBc@qnP6  
<<MpeMi  
String sURL; //File URL iXnXZ|M  
long nStartPos; //File Snippet Start Position LsERcjwwK  
long nEndPos; //File Snippet End Position ekyCZ8iai  
int nThreadID; //Thread's ID gE\ ^ vaB  
boolean bDownOver = false; //Downing is over %BkE %ZcZ  
boolean bStop = false; //Stop identical K& ^qn&  
FileAccessI fileAccessI = null; //File Access interface :zKW[sF  
iLSUz j`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3/n?g7B  
{ }/1^Lqfnz  
this.sURL = sURL; u$%C`v
>  
this.nStartPos = nStart; }?Y -I> w  
this.nEndPos = nEnd; q
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nThreadID = id; u9S*2'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }NC$Ce  
} Y0,{fw<  
u?72]?SM  
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public void run() ,g7O   
{ EWDsBNZaI  
while(nStartPos < nEndPos && !bStop) WS n>P7sY  
{ " C0dZ  
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o!UB x<4  
try{ Hu<]*(lK%  
URL url = new URL(sURL); lot`6]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @QmN= X5  
httpConnection.setRequestProperty("User-Agent","NetFox"); O6y:e#0z  
String sProperty = "bytes="+nStartPos+"-"; ck]I?  
httpConnection.setRequestProperty("RANGE",sProperty); o4FHR+u<M  
Utility.log(sProperty); 45.ks.  
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InputStream input = httpConnection.getInputStream(); 0j!<eN=  
//logResponseHead(httpConnection); 5"nq h}5  
@~hy'6/  
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byte[] b = new byte[1024]; $;Fx Zkp  
int nRead; }cMkh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :} =lE"2  
{ ]}/Rl}_  
nStartPos += fileAccessI.write(b,0,nRead); PzKTEYJL  
//if(nThreadID == 1) %^lD  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FA-cTF[,(  
} ZskX!{  
j$Ndq(<tG  
p}pRf@(`\  
Utility.log("Thread " + nThreadID + " is over!"); [6l0|Y  
bDownOver = true; -hnNaA  
//nPos = fileAccessI.write (b,0,nRead); }'wZ)N@  
} "|(.W3f1  
catch(Exception e){e.printStackTrace ();} %|H]T]s  
} eowwN>-2C  
} Y(6evo&IR  
`G!HGzVx;j  
Nxt:U{`T'  
//打印回应的头信息 &'^.>TJ\  
public void logResponseHead(HttpURLConnection con) %N&.B  
{ )I*(yUj  
for(int i=1;;i++) &mtt,]6C_  
{ *yT>  
String header=con.getHeaderFieldKey(i); !o`7$`%Wz\  
if(header!=null) -'qVnu  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); QErdjjgE  
Utility.log(header+" : "+con.getHeaderField(header)); '9u?lA^9$  
else ^dLu#,;  
break; {K+f&75  
} +r"}@8/\1  
} eef&ZL6g  
>(P(!^[f  
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public void splitterStop() G8vDy1`q6  
{  I\_2=mL  
bStop = true; 6HBDs:   
} u3qxG3  
}kQ{T:q4  
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} %`
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/* QBXEM=  
**FileAccess.java Z:^#9D{  
*//文件访问(定位，写)  &ox  
package NetFox; gk| % 4.  
import java.io.*; (<>??(VM  
eEBNO*2  
>ymn&_zlT  
public class FileAccessI implements Serializable{ 2iM}YCV  
hNh!H<}|m8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 .*YF{!R`h  
RandomAccessFile oSavedFile; I1m[M?  
long nPos; .F$}a%  
%J2Ad  
Gn4b*Y&M]3  
public FileAccessI() throws IOException k^|z.$+  
{ D"aK;_W@h  
this("",0); qdZ ^D  
} o_Z9\'u  
x&DqTX?b,  
7xO05)bz  
public FileAccessI(String sName,long nPos) throws IOException '.z7)n  
{ 8/j|=Q,5  
oSavedFile = new RandomAccessFile(sName,"rw"); ?XdvZf $  
this.nPos = nPos; L&s~j/pR  
oSavedFile.seek(nPos); @!oN]0`F;  
} i|z=WnF$&  
Drtg7v{@\  
@` Pn<_L  
public synchronized int write(byte[] b,int nStart,int nLen) wxcJ2T dH  
{ l(rm0_  
int n = -1; K
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try{ Hy:x.'i  
oSavedFile.write(b,nStart,nLen); @C@9Tw2Y  
n = nLen; 9Br+]F_i  
} @d{}M)6\!
 
catch(IOException e) U/{t"e  
{ aNKw.S>  
e.printStackTrace (); BMO,eQcB  
} U@).jpN  
6_" n  
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return n; G"&$7!6[Y  
} [sG`D-\P[  
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} @F(e
r  
>F^$ ' b]  
_YR#J%xa  
/* 7Fpa%N/WL  
**SiteInfoBean.java "JmbYb#Z  
*/ gNxv.6Pp=  
package NetFox; Q(N'Oj:J  
-SD:G]un  
{(-923|,  
public class SiteInfoBean { A4l"^dZc  
vh"';L_*37  
Z(RsB_u5  
private String sSiteURL; //Site's URL Mfz(%F|<  
private String sFilePath; //Saved File's Path wH@<0lw`<  
private String sFileName; //Saved File's Name GB `n  
private int nSplitter; //Count of Splited Downloading File Bi fI.2|  
0e"KdsA:<U  
\4$Nx/@Q}  
public SiteInfoBean() o"RE4s\G~r  
{//nSplitter的缺省值为5 o/ \o-kC}  
//default value of nSplitter is 5 
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this("","","",5); o(v`  
} ~7}no}7  
*tZ3?X[b  
mhIGunK;+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n@@tO#!\  
{ uTbMp~cYB  
sSiteURL= sURL; R'K /\   
sFilePath = sPath; 6x;"T+BSSS  
sFileName = sName; AsZyPybq  
this.nSplitter = nSpiltter; bg4VHT7?>)  
=8r,-3lC;  
:]C\DUBo  
} v Ma$JPauI  
8r\xQr'8h  
)[sSCt]  
public String getSSiteURL() b[;3y/X  
{ Q%GLT,f1.  
return sSiteURL;
\BsvUGd  
} DUm/0q&  
m} =<@b:l  
ER$~kFE2yP  
public void setSSiteURL(String value)  93`  
{ zgpPu4t  
sSiteURL = value; IZ4jFgpR  
} uqy~hY  
\}qv}hU  
VHws9)  
public String getSFilePath() QaEXk5>e  
{ ':]w  
return sFilePath; L/cbq*L  
} ]zK} X!  
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public void setSFilePath(String value) Y!s/uvRI  
{ qdu:kA:]  
sFilePath = value; r>q
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} N=L urXv  
mKq9mA"(E  
ck<4_?1]  
public String getSFileName() )ZmE"  
{ I3aEg  
return sFileName;
_H3cqD  
} ]X _&  
h;unbz  
*:_hOOT+[  
public void setSFileName(String value) Yr,1##u  
{ QBo^{],  
sFileName = value; \%VoX`B  
} pV+;/y_
 
6a!X`%N=  
8UZEC-K  
public int getNSplitter() ?d%}K76V<  
{ 7I
 
return nSplitter; #WG(V%f]  
} n(+:l'#H
J  
=w5w=qB  
3WVHI$A9  
public void setNSplitter(int nCount) MG@19R2s  
{ *\>2DUu\`  
nSplitter = nCount; )w
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} F*=RP$sj  
} [`lAc V<  
Z0=OR^HjA  
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/* ^J_hkw~gO  
**Utility.java "gz;Q  
*/ ^q`*!B9@  
package NetFox; \zUsHK?L"t  
v=>Gvl3&U  
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public class Utility { #`$7$Y~]  
(
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d8#j@='a*  
public Utility() 2cg z n@  
{ 1c!},O  
De_</1Au!2  
P$Q&xN<#)  
} \t@`]QzG:  
rE:>G]j6  
//线程睡眠 N3<Jh  
public static void sleep(int nSecond) b3lpNJ J  
{ l0{DnQA>I  
try{ ltR^IiA}  
Thread.sleep(nSecond); xF;v 6d  
} Pa +BE[z  
catch(Exception e) ZZ*k3Ce  
{ w ZAXfNA  
e.printStackTrace (); tqCg<NH.!m  
} 5nAF=Bj  
} (K6StNtN  
;[ueNP%*y|  
//日志 rgKn=8+a  
public static void log(String sMsg) [Gy'0P(EQ  
{ ':]a.yA\1  
System.err.println(sMsg); H~]o]uAi"  
} 5i#w:O\cz  
_ZBR<{  
FaE orQ  
public static void log(int sMsg) wtS*w  
{ [uQZD1<q  
System.err.println(sMsg); UE w3AO  
} ZS]f+}0/}  
} e622{dfVS  
&Ld8Z9IeFp  
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/* [_b='/8  
**TestMethod.java JSK5x(GlH  
*/ hP8&n9o  
package NetFox; agT[y/gb  
Lu.tRZ`$38  
{NgY8wQB  
public class TestMethod { a' o8n6i  
BrMp_M  
_)2TLA n3  
public TestMethod() 3MJWCo-[  
{ ///xx/weblogic60b2_win.exe |o=ST  
try{ luk2fi<$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F{~r7y;0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ULmdt   
SiteFileFetch fileFetch = new SiteFileFetch(bean); {eN{Zh5"  
fileFetch.start(); oHd0 <TO  
} SliQwm5  
catch(Exception e){e.printStackTrace ();} Z;SG<  
P3ev4DL  
42wC."A  
} 4eL54).1O  
>@

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bK$D lBZ  
public static void main(String[] args) j{Jc6U  
{ T^
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new TestMethod(); <&EO=A  
} )X!DCL:16  
} !XA%[u  
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