http断点续传简单实现（java)

/* am+w<NJ(us  
**SiteFileFetch.java 7ro&Q%  
*/ gAr=fq-|  
package NetFox; )18C(V-x  
import java.io.*; ToX--w4  
import java.net.*; \dJOZ2J<z  
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public class SiteFileFetch extends Thread { hMnm>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean i!;9A6D  
long[] nStartPos; //开始位置 _"[Ls?tRX  
long[] nEndPos; //结束位置 6KDm#7
J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 qT~a`ou:  
long nFileLength; //文件长度 \wF-[']N  
boolean bFirst = true; //是否第一次取文件 i"d&U7Q  
boolean bStop = false; //停止标志 t W}"PKv  
File tmpFile; //文件下载的临时信息 MFQyB+Z  
DataOutputStream output; //输出到文件的输出流 <S3s==Cg  
&a.A8v)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Z -fiJ75  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'Y0h w  
{
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siteInfoBean = bean; __Zex5Y#-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); mx5#K\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); kgh0  
if(tmpFile.exists ()) s;cGf+  
{ pGd@%/]AO  
bFirst = false; Zm*qV!  
read_nPos(); o3JSh=  
} "h-ZwL  
else _p^$.\k"  
{ NG_7jZzXA9  
nStartPos = new long[bean.getNSplitter()]; jss.j~
8  
nEndPos = new long[bean.getNSplitter()]; {5]c\_.  
} 72ZoN<c  
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} 28qlp>U  
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public void run() 9oYE  
{ 0D Lw  
//获得文件长度 Zc'^iDAY  
//分割文件 ,b4o
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//实例FileSplitterFetch uS5G(}[
 
//启动FileSplitterFetch线程 25 cJA4  
//等待子线程返回 (hEg
&@  
try{ (67byO{  
if(bFirst) u+^KP>rM(  
{ 60 %VG  
nFileLength = getFileSize(); 09qfnQG  
if(nFileLength == -1) BA[ uO3\4  
{ #p ;O3E@  
System.err.println("File Length is not known!"); #\ uB!;Q  
} fN/;BT  
else if(nFileLength == -2) (eAz nTU  
{ 7>=
 
System.err.println("File is not access!"); 0SQrz$y  
} pHXs+Ysw+  
else
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{ <HtGp6q  
for(int i=0;i<nStartPos.length;i++) =R
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{ 6_:I~TTX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Fv*Et-8tN5  
} e_"m\e#N  
for(int i=0;i<nEndPos.length-1;i++) $01csj  
{ &u~Pp=kv  
nEndPos = nStartPos[i+1]; y)"rh/;  
} #0PZa$kM(o  
nEndPos[nEndPos.length-1] = nFileLength; S+"Bq:u"  
} TOhWfl;  
} mfG m>U  
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E*h!{)z@F  
//启动子线程 YmpaLZJ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; JfY(};&  
for(int i=0;i<nStartPos.length;i++)  S'\e"w  
{ ,Js-'vX  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), % m"Qg<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,,!P-kK$  
nStartPos,nEndPos,i); |]9L#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zk"8mTg  
fileSplitterFetch.start(); iCLH  
} TW|- 0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vZW[y5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8+J>jZ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", F{.\i*$  
nEndPos = " + nFileLength); ANNVE},  
// fileSplitterFetch[nPos.length-1].start();
9ln=f=  
q#@r*hl  
t|mK5aR4  
//等待子线程结束 bLSc=f&  
//int count = 0; #4JLWg  
//是否结束while循环 T:@7EL  
boolean breakWhile = false; k~gOL#$  
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while(!bStop) ,<Z,-0S  
{ \7%#4@;?  
write_nPos(); wZN_YFwQ  
Utility.sleep(500); nzaA_^`mB  
breakWhile = true; iPkCuLQ}  
:w!hkUx#  
!^ad{#|X  
for(int i=0;i<nStartPos.length;i++) 7BL)FJ]UR]  
{ TQmrL  
if(!fileSplitterFetch.bDownOver) M9afg$;.xe  
{ DIw_"$'At  
breakWhile = false; -U\'Emu4  
break; %<x!mE x  
} %1$#fxR  
} P%H Dz  
if(breakWhile) Fe4>G8uuwn  
break; ca,W:9#.xn  
IRwtM'%0  
-- FzRO{D  
//count++; JSi0-S[Y{  
//if(count>4)
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// siteStop(); fIl!{pv[  
} jw9v&/-  
_Z!@#y@j  
GGhk~H4OP  
System.err.println("文件下载结束！"); i#hFpZ6u  
} ~!!\#IX  
catch(Exception e){e.printStackTrace ();} dJ m9''T')  
} ~D>pu%F  
b,YNCb]H  
3F@P$4!#l  
//获得文件长度 Eh ";irE  
public long getFileSize() $xbW*w  
{ k}
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int nFileLength = -1; I8j:{*h  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); IhBc/.&RL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p7@R+F\.};  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~!5=o{wy  
rv(?%h`  
4l%1D.3-O  
int responseCode=httpConnection.getResponseCode(); w3ni@'X8  
if(responseCode>=400) ?h&?`WO(  
{ Hcwfe=K&/  
processErrorCode(responseCode); J-Tiwl  
return -2; //-2 represent access is error Zi.
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} $\Y&2&
1s  
pITF%J@_]  
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String sHeader; Pv/v=s>X  
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bY=[ USgps  
for(int i=1;;i++) R-j*fO}  
{ GPK\nz
}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); DegbjqZ#  
//Utility.log(in.readLine()); /De~K+w7o  
sHeader=httpConnection.getHeaderFieldKey(i); .= ?*Wp  
if(sHeader!=null) cO*g4VL"[  
{ N UX |  
if(sHeader.equals("Content-Length")) QJRnpN/
 
{ sHc-xnd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); - ~|Gwr"  
break; %&yPl{  
} )\=
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} w+R7NFq  
else >e>3:~&2  
break; 6<<"9mxK  
} (pd$?vRy  
} &<]f-  
catch(IOException e){e.printStackTrace ();} B(++*#T!^m  
catch(Exception e){e.printStackTrace ();} P .m@|w&.K  
.Mb[j1L^  
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Utility.log(nFileLength); L|T?,^  
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, :#bo]3  
return nFileLength; YE{ [f@i0  
} Qk:Lo*!  
mGj)Zrx>  
5M~{MdF|.  
//保存下载信息（文件指针位置） `a4&_`E,p  
private void write_nPos() q\?s<l63  
{ $TXxhd 6  
try{ ovTL'j!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QMsq4yJ)%  
output.writeInt(nStartPos.length); fUkqhqe  
for(int i=0;i<nStartPos.length;i++) L^ J|cgmNw  
{ w3(|A> s3  
// output.writeLong(nPos); q[a\a7U z  
output.writeLong(fileSplitterFetch.nStartPos); ],pB:=  
output.writeLong(fileSplitterFetch.nEndPos); ^w\22 Q  
} p
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output.close(); heCM+=#~  
} 1N8] ~j  
catch(IOException e){e.printStackTrace ();} UxTLr-db^  
catch(Exception e){e.printStackTrace ();} phuiLW{&  
} *9EwZwE_K  
A_zCSRF,  
BB/wL_=:  
//读取保存的下载信息（文件指针位置） -[L\:'Gp5  
private void read_nPos() tF`L]1r>  
{ \Y)HSJR;e  
try{ Z^&G9I#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~R w1
 
int nCount = input.readInt(); WzN c=@[W  
nStartPos = new long[nCount]; #T_!-;(Z  
nEndPos = new long[nCount]; '" "v7  
for(int i=0;i<nStartPos.length;i++) A-C
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{ 9j>2C  
nStartPos = input.readLong(); vn^O m-\  
nEndPos = input.readLong(); 't5ufAT  
} #cfiN b}GX  
input.close(); Fvl\.  
} 8(%F{&<;  
catch(IOException e){e.printStackTrace ();} G;G*!nlWf  
catch(Exception e){e.printStackTrace ();} JY#vq'dl|  
} X3:z=X&Zd  
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private void processErrorCode(int nErrorCode) cmG27\cRO  
{ ;{sZDjev>  
System.err.println("Error Code : " + nErrorCode); d&FXndC4F  
} BV~J*e  
&)1.z7T  
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//停止文件下载 )[Tm[o?Y.  
public void siteStop() D$}8GYq  
{ 8!{*!|Xd  
bStop = true; 2<EV iP9  
for(int i=0;i<nStartPos.length;i++) ?}cmES kX@  
fileSplitterFetch.splitterStop(); ,<
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Z@0tZ^V{  
} ?.46X^  
} _`udd)Y2  
//负责部分文件的抓取 Z!"-LQJ  
**FileSplitterFetch.java U6M~N0)Yr  
*/ ; j!dbT~5  
package NetFox; bej(Ds0  
]->"4,}  
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import java.io.*; D;pI!S<#  
import java.net.*; =0g!Q  
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public class FileSplitterFetch extends Thread { 4E^ ?}_$  
H0afu)$,  
gXdMGO>  
String sURL; //File URL 0~qc,-)3  
long nStartPos; //File Snippet Start Position Pao^>rj  
long nEndPos; //File Snippet End Position > <YU'>%  
int nThreadID; //Thread's ID t eY@)F  
boolean bDownOver = false; //Downing is over zEI+)|4?r  
boolean bStop = false; //Stop identical 9&Jf4lC94  
FileAccessI fileAccessI = null; //File Access interface M&V'*.xz  
xS,24{-HJ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6m:$mhA5  
{ GmHDG-  
this.sURL = sURL; =0Z
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this.nStartPos = nStart; !?P8[K  
this.nEndPos = nEnd; Nm
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nThreadID = id; dR S:S_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &u>dKf)5  
} 3a?-UT!  
-l= 4{^pK  
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public void run() xe!bfzU  
{ 8fXiadP#  
while(nStartPos < nEndPos && !bStop) M
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{ Dkz/hg:q  
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try{
{18
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URL url = new URL(sURL); e(0OZ_w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ehx9-*]
 
httpConnection.setRequestProperty("User-Agent","NetFox"); Tv=lr6t8  
String sProperty = "bytes="+nStartPos+"-"; S^rf^%  
httpConnection.setRequestProperty("RANGE",sProperty); `8!9Fp  
Utility.log(sProperty); h=#w< @  
7}
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! ?g+'OM  
InputStream input = httpConnection.getInputStream(); ix!xLm9\  
//logResponseHead(httpConnection); m/=nz.  
A=N$5ZJ  
28!C#.(h  
byte[] b = new byte[1024]; AP&//b,^M  
int nRead; CP7dn/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) C"I jr=w  
{ t(z]4y  
nStartPos += fileAccessI.write(b,0,nRead); gNCS*a  
//if(nThreadID == 1) =D`8,n [  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Scrj%h%[  
} xo[o^go  
.t "VsY|  
_?~%+Oz/  
Utility.log("Thread " + nThreadID + " is over!"); T8^9*]:@c!  
bDownOver = true; f^F;`;z  
//nPos = fileAccessI.write (b,0,nRead); *Al@|5  
} >d +
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catch(Exception e){e.printStackTrace ();} b$_81i  
} 7gC?<;\0  
} !.vyzCJTzB  
=[(34#  
&QHJ%c  
//打印回应的头信息 j,0`k  
public void logResponseHead(HttpURLConnection con) Z8SwW<{ $  
{  2v{WX  
for(int i=1;;i++) FLi'}C  
{ 6<lo0PQ"Z  
String header=con.getHeaderFieldKey(i); x92^0cMf  
if(header!=null) y]h0c<NP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !..<_qfw  
Utility.log(header+" : "+con.getHeaderField(header)); :K| H/kht  
else 'PF>#
X''  
break; m}"Hm(,6  
} eEZgG=s  
} f$lb
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public void splitterStop() 0m_yW$w  
{ )3h\QE!z  
bStop = true; QEyL/#Q  
} :33@y%>L
 
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} I6.rN\%b  
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/* FGV L[\  
**FileAccess.java a"jE\OZ{+s  
*//文件访问(定位，写) &L8RLSfX  
package NetFox; t13V>9to  
import java.io.*; Z[?n{vD7  
-XBZ1q  
\=%lH=yS  
public class FileAccessI implements Serializable{ z!}E2j_9P  
6 U.Jaai:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 a4*v'Xc5  
RandomAccessFile oSavedFile; Q"&Mr+  
long nPos; V*?c
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public FileAccessI() throws IOException ~,)jZ-fw  
{ 6W i n!4  
this("",0); d/d)MoaJ*t  
} hP6f  
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public FileAccessI(String sName,long nPos) throws IOException F[ E'R.:  
{ '@{:FrG*U  
oSavedFile = new RandomAccessFile(sName,"rw"); io#}z4"'qY  
this.nPos = nPos; Ju+3}  
oSavedFile.seek(nPos); |*bUcS<S  
} tq L(H25z  
"to!&@I| 4  
{nmG/dn{  
public synchronized int write(byte[] b,int nStart,int nLen) # -'A =j  
{ lod+]*MD  
int n = -1; m.<_WXH  
try{ jq~`rE h9  
oSavedFile.write(b,nStart,nLen); Rta}*  
n = nLen; /v!yI$xc  
} *)K 5<}V  
catch(IOException e) Sz0PZtJ  
{ _o~ pVBl/  
e.printStackTrace (); ktyplo#F  
} i~u4v3r=  
0%f}Q7*R  
u({^8: AYu  
return n; .<m]j;|6  
} Zl>SeTjB-  
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} #49l\>1z  
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45yP {+/-Q  
/* K,S4  
**SiteInfoBean.java 3fOOT7!FL  
*/ MzvhE0ab  
package NetFox; tD8fSV  
/zIG5RK>  
kz=ho~ @  
public class SiteInfoBean { 3bRxV @0.  
Gk:fw#R  
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private String sSiteURL; //Site's URL o0r&w;!  
private String sFilePath; //Saved File's Path Ct=bZW"j/  
private String sFileName; //Saved File's Name VEWW[T  
private int nSplitter; //Count of Splited Downloading File ?1=.scmgDG  
kQ+y9@=/g  
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public SiteInfoBean() S m(*<H  
{//nSplitter的缺省值为5 m H:Un{,  
//default value of nSplitter is 5 vobC/m  
this("","","",5); ~n 'A1  
} %H\b5& _y  
R0?bcP&  
uda++^y:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Cd'D ~'=  
{ _ZRmD\_t  
sSiteURL= sURL; J^8j|%h%e  
sFilePath = sPath; >LPb>t5%p  
sFileName = sName; Fyvo;1a  
this.nSplitter = nSpiltter; Pt"K+]Ym  
h8V*$  
,:Px(=d4  
} Yn?beu'  
2IYzc3Z{9  
g9C;JmU  
public String getSSiteURL() "leSQ  
{ y[McdlH m  
return sSiteURL; p[4 +`8  
} 2$JZ(qnN  
hj];a,Br&  
A"*=K;u/|m  
public void setSSiteURL(String value) >Tf}aI+  
{ G2`YZ\  
sSiteURL = value; %M x|"ff  
} q^[t</_N  
e;6:U85LS  
`}Y)l:G*g  
public String getSFilePath() 3,i j@P  
{ XL*M#Jx  
return sFilePath; }8#olZ/(q  
} !Yc:yF  
!gI0"p?  
o@A`AA9  
public void setSFilePath(String value) M7BpOmK'  
{ c|<F8n  
sFilePath = value; hNc8uV{r=  
} CVO_F=;  
xa`xHh{0  
,!> ~izB  
public String getSFileName() 4Uny.C]  
{ Yo%U{/e  
return sFileName; 7~2_'YX>:  
} th{J;a  
U)dcemQY  
8*-)[+s9il  
public void setSFileName(String value) ,Ee5}#dI  
{ DT-.Gdb8  
sFileName = value; u-~ec{oBu  
} DVd8Ix<  
";.j[p:gi  
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public int getNSplitter()  ]j0+4w  
{ {^oohW -  
return nSplitter; wXQu%F3  
} ~2*LWH*@  
r (m3"Xu6O  
-gGw_w?)(  
public void setNSplitter(int nCount) M2%@bETJ  
{ jNxTy UU  
nSplitter = nCount; X&[Zk5DU*  
} KaEaJ  
} kO)Y|zQ  
!WXV1S  
,OlS>>,  
/* |2'WSAWG  
**Utility.java .7.1JT#@A7  
*/ -+F,L8  
package NetFox; &/m^}x/_W  
!=S?*E +j)  
'n h^
;  
public class Utility { `NhG|g  
tHzgZoBz  
0$Tb5+H5  
public Utility() v,n 8$,  
{ :G6CWE  
8`S1E0s  
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} n\;;T1rM  
XrUI[ryE  
//线程睡眠 .?:#<=1  
public static void sleep(int nSecond) Q>L(=j2t  
{ [%^0L~:  
try{ hV $Zr4'  
Thread.sleep(nSecond); ";dS~(~  
} \asn^V@"zz  
catch(Exception e) XR]bd  
{ ;):;H?WS|A  
e.printStackTrace (); `Ku:%~$/  
} <e! TF@  
} KxErWP%  
>}wFePl  
//日志 _'!qOt7D  
public static void log(String sMsg) p7AsNqEp  
{ ]ovtH

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System.err.println(sMsg); OM.-apzC  
} b B#QIXY/L  
~5Fx[q  
wYe;xk`>  
public static void log(int sMsg) }alq~jY  
{ <IIz-6*V  
System.err.println(sMsg); }bihlyB&Q  
} st??CX2  
} n^1BtP0!  
p+Q9?9  
##By!FTP  
/* Fr50hrtkU  
**TestMethod.java mfj%-)l9  
*/ `i|!wD,=\  
package NetFox; ")9^  
)09ltr0@"  
?h1g$SBxk  
public class TestMethod { w3i74C&0  
h>>~Bi  
-5v{p  
public TestMethod() kJ%a;p`O  
{ ///xx/weblogic60b2_win.exe 4,@jSr|I3i  
try{ pj7al;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +PBl3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p+ReQ.5|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); S*n5d>;  
fileFetch.start(); 5
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} Tcv/EST  
catch(Exception e){e.printStackTrace ();} {li Q&AZ  
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} 9e.v[K~  
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zA?AX1%Wa  
public static void main(String[] args) 3ut<o-
 
{ },X.a@:  
new TestMethod(); ^d
# AU7V|  
} Uo9@Y{<B  
} @ o<OI  
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