http断点续传简单实现（java)

/* 68V66:0  
**SiteFileFetch.java 1Cki}$k@  
*/ (NyS2`  
package NetFox; E)H: L-  
import java.io.*; )TnxsFC  
import java.net.*; \`;FL\1+W  
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public class SiteFileFetch extends Thread { ),v[.9!}:  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (s4w0z  
long[] nStartPos; //开始位置 q]T{g*lT  
long[] nEndPos; //结束位置 
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 U2\g Kg[-Q  
long nFileLength; //文件长度 f;!1=/5u-  
boolean bFirst = true; //是否第一次取文件 ;| ##~Y.9  
boolean bStop = false; //停止标志 @Iia>G@Rz  
File tmpFile; //文件下载的临时信息 oFB~)}f<v  
DataOutputStream output; //输出到文件的输出流 Ac0C
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @G+Hrd6  
public SiteFileFetch(SiteInfoBean bean) throws IOException UX}ZE.cV  
{ !*HH5qh6  
siteInfoBean = bean; <k-&Lh:o3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >p [|U`>{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xQ\/6|  
if(tmpFile.exists ()) Y!c RzQ  
{ I:CnOpR>A  
bFirst = false; ? acm5dN  
read_nPos(); .Qm"iOyM  
} [g`9C!P-G  
else ~B;kFdcVXn  
{ ()e.J  
nStartPos = new long[bean.getNSplitter()]; |Wd]:ijJ  
nEndPos = new long[bean.getNSplitter()]; wvBx]$SC  
} ,l^; ZE  
8,=N~(pd`  
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} ~XQj0'  
z )s{>^D  
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public void run() 3>YG  
{ LsH&`G^<  
//获得文件长度 'Vq <;.A  
//分割文件 #Jp_y|  
//实例FileSplitterFetch 1"?3l`i  
//启动FileSplitterFetch线程 FDBj<uXfM|  
//等待子线程返回 t0h@i`  
try{ :tU&d(8  
if(bFirst) L;N)l2
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{ gEcRJ1Q;C  
nFileLength = getFileSize(); 0NrUB  
if(nFileLength == -1) x>:~=#Vi  
{ kx&Xk0F_g  
System.err.println("File Length is not known!"); uJ<nW%}  
} Z BjyQ4h  
else if(nFileLength == -2) bC*( ,n<'  
{ ~R^~?Y%+<  
System.err.println("File is not access!"); dz@L}b*  
} g$bbm}6S  
else )7!q>^S{B  
{ =j#1HI=Fe  
for(int i=0;i<nStartPos.length;i++) 9RA~#S|(T  
{ qd$Y"~Mco  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r+%:rFeX  
} 4UwXrEQp  
for(int i=0;i<nEndPos.length-1;i++) !SRElb A;i  
{ $>Md]/I8  
nEndPos = nStartPos[i+1]; A+Uil\%  
} &j=FxF9o  
nEndPos[nEndPos.length-1] = nFileLength; lh^-L+G:Ok  
} RhwqAok|lj  
} );EW(7KeL  
`w/:o$&  
'YQ^K`lV  
//启动子线程 ]^aOYtKX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 12l-NWXf  
for(int i=0;i<nStartPos.length;i++) rXl ~D!  
{ $Ro]]NUz|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =AEl:SY+  
nStartPos,nEndPos,i); iA*^`NMaT  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9vIqGz-o  
fileSplitterFetch.start(); 0zJT_H+  
} NQBa+N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t~_j+k0K#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); abog\0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~)J]`el,Q  
nEndPos = " + nFileLength); K>
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// fileSplitterFetch[nPos.length-1].start(); >i&"{GZ  
{WokH;a/
 
=[A5qwyv  
//等待子线程结束 ]oOSL=~c  
//int count = 0; RbOEXH*]  
//是否结束while循环 9Yu63s ia  
boolean breakWhile = false; <jt_<p +  
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while(!bStop) hY*ylzr83  
{ %E<.\\^%  
write_nPos(); o )\\(^ld  
Utility.sleep(500); +\Hh|Uz5  
breakWhile = true; 0`WjM2So  
]|H`?L  
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for(int i=0;i<nStartPos.length;i++) RN,5>.w  
{ V(gmC%6%l*  
if(!fileSplitterFetch.bDownOver) seQSDCsvw*  
{ C0f<xhp?j  
breakWhile = false; "+0Yhr?  
break; 4*`AYx(  
} dM-qd`
  
} L3N?^^]  
if(breakWhile) 0f_+h %%=  
break; TTYM!+T  
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//count++; VtTTvP3  
//if(count>4) s0zN#'o]  
// siteStop(); b(E}W2-t  
} RJpRsr  
DPWt=IFU  
hSN{jl{L`  
System.err.println("文件下载结束！"); kVmRv.zZ  
} v3*y43  
catch(Exception e){e.printStackTrace ();} xmM!SY>  
} bHKTCPf  
4ZUTF3  
3BZa}Q_  
//获得文件长度 S|jE1v"L  
public long getFileSize() x>]14bLz  
{ $q|-9B  
int nFileLength = -1; xS'Kr.S  
try{ ron-v"!  
URL url = new URL(siteInfoBean.getSSiteURL()); n%S%a>IQj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p{vGc-zP.  
httpConnection.setRequestProperty("User-Agent","NetFox"); =,Zkg(M  
)K}-z+$)k  
69"4/n7B?  
int responseCode=httpConnection.getResponseCode(); 4@mK:v%  
if(responseCode>=400) mEZHrr J  
{ V+$^
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processErrorCode(responseCode); C>:,\=y%  
return -2; //-2 represent access is error 94}y,\S~  
} |Wg!>g!  
6uTFgSqZ  
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String sHeader; KXiStwS  
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for(int i=1;;i++) *UZd!a)  
{ ?u4t;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V<i_YLYmJe  
//Utility.log(in.readLine()); r [E4/?_  
sHeader=httpConnection.getHeaderFieldKey(i); 2PC:F9dh\  
if(sHeader!=null) M#.dF{%%  
{ XE$;Z'Qhjm  
if(sHeader.equals("Content-Length")) tPb<*{eG  
{ &U_T1-UR2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _&RGhA  
break; 7P:/ (P  
} .^wBv 'Y  
} T`2a)  
else U.Fs9F4M#  
break; E^B3MyS^^  
} e
8 c.&j3m  
} wWVB'MRXB,  
catch(IOException e){e.printStackTrace ();} Dn48?A[v  
catch(Exception e){e.printStackTrace ();} @GWlo\rM6^  
5Y>fVq{U?;  
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Utility.log(nFileLength); |*g\-2j{  
J
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return nFileLength; r2\}_pIj  
} +bk+0k9k5  
3$3
%W<&^  
kbSl.V%)  
//保存下载信息（文件指针位置） *rVI[kL  
private void write_nPos() 63'L58O  
{ 5R6QZVc  
try{ 7#j9"*
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,U~in)\ U  
output.writeInt(nStartPos.length); %edTW[C`  
for(int i=0;i<nStartPos.length;i++) L>pSE'}  
{ ~i0>[S3'  
// output.writeLong(nPos); xLP8*lvy  
output.writeLong(fileSplitterFetch.nStartPos); 24*3m&fA*K  
output.writeLong(fileSplitterFetch.nEndPos); l-2lb&n  
} b?/Su<q  
output.close(); \[ W`hhJ  
} 1 J[z ![Tf  
catch(IOException e){e.printStackTrace ();} @9lGU#  
catch(Exception e){e.printStackTrace ();} *, R ~[g  
} ]YY4{E(9d  
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//读取保存的下载信息（文件指针位置） 9hgIQl  
private void read_nPos() 1[-RIN;U8  
{ rIX 40,`  
try{ !Pu7%nV.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \==Mgy2J8  
int nCount = input.readInt(); r;O?`~2'4  
nStartPos = new long[nCount]; M"foP@  
nEndPos = new long[nCount]; Mo]iVj8~  
for(int i=0;i<nStartPos.length;i++) }Qh%Z)  
{ knzQ)iv&&  
nStartPos = input.readLong(); ]''tuo2g8  
nEndPos = input.readLong(); bd3>IWihp  
} #fFD|q  
input.close(); qnzNJ_ `R  
} X^C $|:  
catch(IOException e){e.printStackTrace ();} ]j.!   
catch(Exception e){e.printStackTrace ();} w$`u_P|@E:  
} I.o3Ol
d  
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private void processErrorCode(int nErrorCode) u@aM8Na  
{ :(I=z6  
System.err.println("Error Code : " + nErrorCode); NM1TFs2Y*  
} :~p_(rE  
6wb M$|yFj  
nTsPX Tat  
//停止文件下载 3]>YBbXvE  
public void siteStop() }'\M}YM  
{ E8o9ufj3  
bStop = true; Y3xEFqMU  
for(int i=0;i<nStartPos.length;i++) 8g/r8u~  
fileSplitterFetch.splitterStop(); R!WeSgKCs  
cSj(u%9}  
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} mN#&NA  
} K4^B~0~  
//负责部分文件的抓取 ?hW(5]p|  
**FileSplitterFetch.java '=IuwCB|;  
*/ G+iJS!=  
package NetFox; ltd'"J/r  
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import java.io.*; ;8gODj:dO
 
import java.net.*; b{W ,wn  
7.C]ZcU  
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public class FileSplitterFetch extends Thread { NmN:x&/  
6uFGq)4p@  
ND5E`Va5R  
String sURL; //File URL JM*rPzp  
long nStartPos; //File Snippet Start Position lqKwjJtX  
long nEndPos; //File Snippet End Position t;[Q&Jl  
int nThreadID; //Thread's ID .|K\1qGW0  
boolean bDownOver = false; //Downing is over uMBb=   
boolean bStop = false; //Stop identical *1}vn%wvn  
FileAccessI fileAccessI = null; //File Access interface _"'-fl98*  
H/ub=,Ej*  
(7v`5|'0  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;"%luQA<w  
{ J1Y3>40  
this.sURL = sURL; NO#^_N`#\  
this.nStartPos = nStart; r3.v^  
this.nEndPos = nEnd; ? oGmGKq  
nThreadID = id; EtB56FU\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fVBRP[,  
} I3?:KVa  
l1RFn,Tzr  
{K2F(kz?T  
public void run() "2@Ys*e  
{ n]btazM{   
while(nStartPos < nEndPos && !bStop) Q1'D*F4  
{ <lLk(fC  
14\!FCe)!  
o-t!z'\l
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try{ yDw^xGws  
URL url = new URL(sURL); D%.<}vG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1'* {VmM  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xgm9>/y  
String sProperty = "bytes="+nStartPos+"-"; Mq,_DQ  
httpConnection.setRequestProperty("RANGE",sProperty); vGPaWYV  
Utility.log(sProperty); )5bdWJ>l  
 ,#
-^  
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InputStream input = httpConnection.getInputStream(); 9$'Edi=6  
//logResponseHead(httpConnection); =j~}];I  
iAWoKW  
sfNAGez  
byte[] b = new byte[1024]; m;I;{+"u  
int nRead; |&%l @X6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %u|qAF2uS  
{ ~LzTqMHM  
nStartPos += fileAccessI.write(b,0,nRead); >:P3j<xTv  
//if(nThreadID == 1) r,dxW5v.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^A$~8?f  
} ^SRa!8z$W  
1vxh3KS.  
E0S[TEDa]  
Utility.log("Thread " + nThreadID + " is over!"); sw &sF  
bDownOver = true; R:JS)>B  
//nPos = fileAccessI.write (b,0,nRead); #$%gs]  
} 9/|i.2&  
catch(Exception e){e.printStackTrace ();} JXnPKAN  
} c5rQkDW  
} IA;KEGJ  
mwTn}h3N  
>Y< y]vM:  
//打印回应的头信息 G8?<(.pi@  
public void logResponseHead(HttpURLConnection con) K+mtuB]yr  
{ Qi7^z;  
for(int i=1;;i++) J0|}u1?l  
{ wGQ{  
String header=con.getHeaderFieldKey(i); Dl/_jM  
if(header!=null) XT_BiZ%l5O  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?8C+wW  
Utility.log(header+" : "+con.getHeaderField(header)); M !OI :v  
else vR~*r6hX8  
break; 49Ue2=PP#  
} @kwD$%*0  
} #(*WxVE  
6YU2  !x  
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public void splitterStop() uf)W?`e~  
{ Lou4M  
bStop = true; .^.UJo;4G  
} 90aPIs-  
^! ZjK-$A<  
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} {Q(6 .0R  
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|2 wff?  
/* xD?{Hw>QT#  
**FileAccess.java /9w}[y*E  
*//文件访问(定位，写) |H_)u  
package NetFox; PewPl0  
import java.io.*; X7c*T /  
Yhw* `"X  
u\.sS|
$  
public class FileAccessI implements Serializable{ G[>-@9_b  
/l$noaskX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 usTCn3u  
RandomAccessFile oSavedFile; };!c]/,  
long nPos; B=c^ma
  
.RWBn~b#I  
tl^[MLQa  
public FileAccessI() throws IOException &s<  
{ [sk"2  
this("",0); _gGy(`  
} Rt:PW}rFf  
GKd>AP_  
6~/H#8Kdn  
public FileAccessI(String sName,long nPos) throws IOException P*T)/A%4  
{ sk3;;<H  
oSavedFile = new RandomAccessFile(sName,"rw"); Hf-F-~E  
this.nPos = nPos; %ej"ZeM  
oSavedFile.seek(nPos); zn~m;0Xi  
} v1lj/A  
P%lLKSA  
T?ZMmUE  
public synchronized int write(byte[] b,int nStart,int nLen) 6e*b;{d  
{ /(0d{  
int n = -1; E37@BfpO3  
try{ &L?Dogo  
oSavedFile.write(b,nStart,nLen); 5~X%*_[],  
n = nLen; d#tUG~jc  
} I^|bQ3sor  
catch(IOException e) 09?<K)_G  
{ ?hu 9c  
e.printStackTrace (); O&s6blD11  
} X>6a@$MxP  
_#F'rl6'  
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return n; <FK><aA_i*  
} W%W. +f  
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} ]xG4T>S  
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/* 4dK@UN\  
**SiteInfoBean.java ({9!P30:  
*/ ?f`-&c;  
package NetFox; F1=+<]!  
v8IL[g6"  
Z9D4;1  
public class SiteInfoBean { 5xHiq&d.E  
8#Z5-",iw  
HKkf+)%)x  
private String sSiteURL; //Site's URL VfwD{+5  
private String sFilePath; //Saved File's Path V"ZbKV+[  
private String sFileName; //Saved File's Name Uk2q,2  
private int nSplitter; //Count of Splited Downloading File bsry([N>w  
XL3h ;$,  
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public SiteInfoBean() f.$o|R=v  
{//nSplitter的缺省值为5 z)~!G~J]  
//default value of nSplitter is 5 +;Gl>$  
this("","","",5); ~e+w@ lK  
} Q=8 cBRe  
zOOX>3^  
iFA"m;$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *La =7y:  
{ M::iU_  
sSiteURL= sURL; #0D.37R+k  
sFilePath = sPath; jQ)>XOok  
sFileName = sName; 5!zvoX9  
this.nSplitter = nSpiltter; \G@6jn1G(  
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"/?qT;<$)  
} 0d ->$gb  
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public String getSSiteURL() ? ^CGJ1  
{ 72zuI4&  
return sSiteURL; A%1=6  
} MGzF+ln^U  
!y`e,(E  
C#&6p0U  
public void setSSiteURL(String value) u&xK>7  
{ ([-=NT}Aq  
sSiteURL = value; o z{j2%  
} syf"{bBe  
61/zrMPn  
8!GLw-kb  
public String getSFilePath() H|U/t
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{ ..!-)q'?  
return sFilePath; :(`>bY  
} Ne7{{1  
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S\5k'ifh  
public void setSFilePath(String value) b H_pNx81  
{ :5{@*  
sFilePath = value; A'1AU:d  
} R?~h7 d  
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As
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public String getSFileName() M%s$F@  
{ ~vV)|  
return sFileName; [?@wCY4=  
} B
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public void setSFileName(String value) az;jMnPpR5  
{
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sFileName = value; 6QXQ<ah"  
} 6.s?  
wrYQ=u#Z  
rDX'oP:  
public int getNSplitter() {IHK<aW  
{ o`mIi  
return nSplitter; hO.G'q$V  
} qd~98FS  
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UX`DZb+^  
public void setNSplitter(int nCount) #6sC&w3  
{ *P R_Y=v%  
nSplitter = nCount; gQ=POJ=G  
} S<!_ uq  
} |zq!CLjD@  
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/* |;9 A{#zM  
**Utility.java !u{"] T:  
*/ Z/kaRnG[@t  
package NetFox; p_qm}zp  
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public class Utility { Jrd4a~XP  
Vt=(2d5:p  
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public Utility() O+p-1 C$\  
{ tNuCxb-  
j'Y"/<  
j8Q5d`  
} E<CxKY9  
mzE$aFu8  
//线程睡眠 Mq:'-`  
public static void sleep(int nSecond) plx/}ah8  
{ ~8xh0TSi  
try{ )d(0Y<e@  
Thread.sleep(nSecond); XyM(@6,'  
} d&T6p&V$  
catch(Exception e)  L;M^>{>  
{ s"',370  
e.printStackTrace (); `}~)1'(#/  
} Q A)9  
} {jM<t  
*e3L4 7"G  
//日志 g"]<J&  
public static void log(String sMsg) n!ZP?]FR  
{ uOl(-Zq@  
System.err.println(sMsg); #W@% K9  
} x, Vh  
4Wla&yy  
1Y"35)CR)  
public static void log(int sMsg) =Esbeb7P  
{ nl'J.dJe  
System.err.println(sMsg); yMbcFDlBr  
} }WO9!E(  
} EARfbb"SG7  
JC&6q>$  
)y`TymM[F  
/* 1rv$?=Z  
**TestMethod.java ,.oa,sku  
*/ r'd:SaU+  
package NetFox; <,@H;|mZ  
&*aer5?`  
y Tw',N{  
public class TestMethod { w.
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1]>$5 1Q  
eyf4M;goz}  
public TestMethod() /~Zc}o,J  
{ ///xx/weblogic60b2_win.exe ~)wwX:;B_  
try{ 'je8k7`VA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Kunle~Ro  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D(qHf9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P(pd0,%i;a  
fileFetch.start(); ]HyHz9QkL  
} G}P)vfcH  
catch(Exception e){e.printStackTrace ();} MOP]\ypn  
$v:gBlj%"  
np-T&Pz2  
} VR4E 2^  
:'d76pM-  
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public static void main(String[] args) (|<h^] y3  
{ Bw3F7W~l  
new TestMethod(); p;qRm} 0}  
} gHi~nEH  
} m3xz=9Ve  
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