http断点续传简单实现（java)

/* 6R1wn&8  
**SiteFileFetch.java KTG:I@|C  
*/ wr$cK'5ZL  
package NetFox; k^H0b\hYY  
import java.io.*; ydwK!j0y  
import java.net.*; FOOQ'o[}  
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public class SiteFileFetch extends Thread { (3 IZ  
{S5RK-ax  
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SiteInfoBean siteInfoBean = null; //文件信息Bean = n+q_.A  
long[] nStartPos; //开始位置 %`xV'2H  
long[] nEndPos; //结束位置
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 RLdlz  
long nFileLength; //文件长度 )KSisEL  
boolean bFirst = true; //是否第一次取文件 :/o C:z\h  
boolean bStop = false; //停止标志 { 1+Cw?1d  
File tmpFile; //文件下载的临时信息 A",eS6  
DataOutputStream output; //输出到文件的输出流 ]b4pI*:$I  
Ik`O.Q.}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F(Lb8\to\M  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5;IT64&]  
{ _PK}rr?"7O  
siteInfoBean = bean; $Y8>_6%+T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /xl4ohL$a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .)LZ`Ge3F  
if(tmpFile.exists ()) 9{_8cpm4  
{ b;S6'7Jf9  
bFirst = false; N]B)Fb  
read_nPos(); VZ\O9lD  
}
^oS$>6|  
else uQH%.A  
{ }x*7l`1  
nStartPos = new long[bean.getNSplitter()]; Ct4LkmD  
nEndPos = new long[bean.getNSplitter()]; lVP9=  
} 2>F
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} PeO]lq  
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public void run() [/ AIKZM<  
{ I[}75:^Rt  
//获得文件长度 ?q\FLb%"7  
//分割文件 %dEB/[  
//实例FileSplitterFetch 7=}6H3|&  
//启动FileSplitterFetch线程 4HM;K_G%{  
//等待子线程返回 +T9Q_e*  
try{ Fj S%n$  
if(bFirst) ,mBZ`X@N  
{ =v.{JV#  
nFileLength = getFileSize(); he"L*p*H  
if(nFileLength == -1) O/mR9[}  
{ r]v&t  
System.err.println("File Length is not known!"); &=YSM.G  
} Yl$X3wi  
else if(nFileLength == -2) m;dm|4L^  
{ Sa L"!uAk  
System.err.println("File is not access!"); +}P%HH]E/p  
} <"<Mbbp  
else 85'nXYN{d  
{ Y=r!2u6r~  
for(int i=0;i<nStartPos.length;i++) *RBV'b  
{ )D;*DUtMVm  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~e{H#*f&1/  
} bG"HD?A_  
for(int i=0;i<nEndPos.length-1;i++) "jT#bIm  
{ 1@xP(XS  
nEndPos = nStartPos[i+1]; %]!adro~  
} F?9SiX[\  
nEndPos[nEndPos.length-1] = nFileLength; Di>rO038  
} 2:Q(Gl`<l  
} ;\qXbL7  
P>(P2~$Y"  
qNxB{0(D  
//启动子线程 VevNG*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Fi4UaJ3K  
for(int i=0;i<nStartPos.length;i++) -p`L%xj\  
{ A?8\Y{FQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *t(4 $  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wO7t!35  
nStartPos,nEndPos,i); 4/'N|c.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XV>@B $hu  
fileSplitterFetch.start(); 'Dath>Y=  
} }$&xTW_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6V1:qp/6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $e }n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l'6d4 DZ  
nEndPos = " + nFileLength); z\TLsx  
// fileSplitterFetch[nPos.length-1].start(); ^z~~VBv  
+6l]]*H  
9[VxskEh  
//等待子线程结束 /1d<P! H  
//int count = 0; "UG K8x  
//是否结束while循环 &J$##B  
boolean breakWhile = false; e"k/d<  
OX\$nQ\o  
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while(!bStop) Z(e^iH  
{ ?qmp_2:WU  
write_nPos(); jnJZ#=)  
Utility.sleep(500); :U'Cor H  
breakWhile = true; e)@3m.  
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7C7>y/uS  
for(int i=0;i<nStartPos.length;i++) 7O)" `  
{ FOH@OY  
if(!fileSplitterFetch.bDownOver) w<NyV8-hL  
{ booRrTS  
breakWhile = false; .TpsJXF  
break; M:n6BC>t"  
} [&#/|zH'j:  
} =sgdkAYwP  
if(breakWhile) 2'|8Q\,:4Z  
break; QA?oJ_}y  
[=uI
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//count++; /Vww?9U;  
//if(count>4) =:=/Gz1  
// siteStop(); `s"d]/85VW  
} d ~`V7B2Y  
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System.err.println("文件下载结束！"); 3^,QIG  
} iPj~I  
catch(Exception e){e.printStackTrace ();} ^YlI>_3s  
} TQ]
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Z9K})47T  
gb" 4B%Hm  
//获得文件长度 -SCM:j%h  
public long getFileSize() ~F!,PM/  
{ H:QhrL+7_  
int nFileLength = -1; Z>P*@S,6G  
try{ $_Nf-:D*  
URL url = new URL(siteInfoBean.getSSiteURL()); w0lT%CPx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nh.32q]  
httpConnection.setRequestProperty("User-Agent","NetFox"); /M=3X||  
*[}^[J x  
/7"I#U^u
/  
int responseCode=httpConnection.getResponseCode(); [k<1`z3  
if(responseCode>=400) {tiKH=&J  
{ [}z,J"Un  
processErrorCode(responseCode); ZZxk]D<  
return -2; //-2 represent access is error :"1|AJo)  
} ]a'99^?\  
/F)H\*  
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String sHeader; =r2]uW9  
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for(int i=1;;i++) hz:pbes  
{ M@et6aud;K  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L%"LlSg  
//Utility.log(in.readLine()); C[sh,  
sHeader=httpConnection.getHeaderFieldKey(i); 6gL-OJNo  
if(sHeader!=null) TrS8h^C
 
{ w_tJ7pz8T  
if(sHeader.equals("Content-Length")) pCi#9=?N  
{ dT"hNHaf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h^UKT`9vt  
break; #W>QY Tp  
} <AH1i@4  
} +Vb8f["+-  
else GL$De,V  
break; X{xBYZv4  
} #%0Bx3uM  
} KLWn?`  
catch(IOException e){e.printStackTrace ();} }_9,w;M$  
catch(Exception e){e.printStackTrace ();} "R>FqX6FB  
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j=RRfFg)  
Utility.log(nFileLength); o\b-_E5"?  
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]:M0Kj&h  
return nFileLength; :rMM4  
} I#F!N6;  
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:Qt  
//保存下载信息（文件指针位置） 8,P- 7^  
private void write_nPos() dP?Ge}  
{ fxaJZz$o  
try{ "hxN!,DEZ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HBS\<}  
output.writeInt(nStartPos.length); 4`m~FNVS  
for(int i=0;i<nStartPos.length;i++) G2bDf-1ew  
{ x!LQxoNF  
// output.writeLong(nPos); aT!'}GjL  
output.writeLong(fileSplitterFetch.nStartPos); nfSbM3D]h  
output.writeLong(fileSplitterFetch.nEndPos); nn/?fIZN4  
} Hb} X-6N  
output.close(); H %JaZ?(  
} K.<.cJE  
catch(IOException e){e.printStackTrace ();} `]Fx.)C#  
catch(Exception e){e.printStackTrace ();} ygJr=_
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} JxE53ev  
i':ydDOOHA  
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//读取保存的下载信息（文件指针位置） 2WX7nK;I  
private void read_nPos() TxjYrzC  
{ nRL. ppUI  
try{ x+ncc_2n&D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); M5nWVK7c  
int nCount = input.readInt(); )c n+1R  
nStartPos = new long[nCount]; (wIzat  
nEndPos = new long[nCount]; )a9 ]US^  
for(int i=0;i<nStartPos.length;i++) >(uZtYM\j  
{ y&}E~5O  
nStartPos = input.readLong(); *4+3ObA  
nEndPos = input.readLong(); x3jb%`o#!  
} %VYAd)gC  
input.close(); x-OA([;/  
} poGc a1  
catch(IOException e){e.printStackTrace ();} !tfb*@{;'  
catch(Exception e){e.printStackTrace ();} ;c~cet4  
} S#)Eom?V  
@k[R/,#'[t  
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private void processErrorCode(int nErrorCode) B~o\+n  
{ 3bk|<7tl  
System.err.println("Error Code : " + nErrorCode); )[0T16  
} f` =CpO*  
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(" LQll9  
//停止文件下载 kt`nbm|aw  
public void siteStop() ];.pK  
{ '!l1=cZD  
bStop = true; "k]CW\H6z  
for(int i=0;i<nStartPos.length;i++) d ;vT ~;  
fileSplitterFetch.splitterStop(); 6"Bic rY  
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| N0Z-|  
} G!K]W:m  
} hX`}Q4(k  
//负责部分文件的抓取 C<KrMRWh^  
**FileSplitterFetch.java B<j'm0a>B  
*/ >e\9Bf_  
package NetFox; 3a.kBzus  
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import java.io.*; =t6z \WB  
import java.net.*; [2"<W!p  
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public class FileSplitterFetch extends Thread { UnI48Y  
7AYd!n&S  
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String sURL; //File URL Fx-8M
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long nStartPos; //File Snippet Start Position 9U$EJN_G  
long nEndPos; //File Snippet End Position ^G6RjJxqp8  
int nThreadID; //Thread's ID ^i:`ZfA#
 
boolean bDownOver = false; //Downing is over (aD_zG=k5  
boolean bStop = false; //Stop identical 5:'hj$~|\1  
FileAccessI fileAccessI = null; //File Access interface z9aY]lHY  
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A&nU]R8S  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gy&[?m6M=  
{ W5SJ^,d)J  
this.sURL = sURL; &f&z_WU  
this.nStartPos = nStart; J_s>N  
this.nEndPos = nEnd; <.Nx[!'~&d  
nThreadID = id; G:zua`u[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H54R8O$  
} &|/| ''A)  
5 ~TdD6}  
[Q=dCX9%  
public void run() 'fW6 .0fXa  
{ bV ZMW/w  
while(nStartPos < nEndPos && !bStop) zN  [2YJ$  
{ eImn+_ N3  
,"B+r6}EF  
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try{ lP<:tR~K  
URL url = new URL(sURL); -jMJAYjV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G "73=8d  
httpConnection.setRequestProperty("User-Agent","NetFox"); =$]uoA  
String sProperty = "bytes="+nStartPos+"-"; 6`f2-f9%iq  
httpConnection.setRequestProperty("RANGE",sProperty); ">#wOm+ +  
Utility.log(sProperty); !Q#{o^{Y~  
lT(oL|{#P  
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InputStream input = httpConnection.getInputStream(); kT;S4B  
//logResponseHead(httpConnection); -wjN"g<  
5}`_x+$%(`  
M)U{7c$c7  
byte[] b = new byte[1024]; 3YVi" k?2  
int nRead; -|E!e.^7:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) OoWyPdC+P  
{ $sEy%-  
nStartPos += fileAccessI.write(b,0,nRead); 'Fm
vu  
//if(nThreadID == 1) o<N nV  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EVoEszR  
} /iX+R@  
0{=`on;  
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Utility.log("Thread " + nThreadID + " is over!"); -;'1^  
bDownOver = true; R)c'#St  
//nPos = fileAccessI.write (b,0,nRead); 3D2E?$dX  
} U~p
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catch(Exception e){e.printStackTrace ();} P>Ez'C  
} J>\B`E  
} 92EWIHEWZ  
Z?\2F%  
}mAa}{_  
//打印回应的头信息 rb|U;)C  
public void logResponseHead(HttpURLConnection con) [i]Ub0Dh7  
{ %"P,1&\^  
for(int i=1;;i++) Dc_yM  
{ @;'o2   
String header=con.getHeaderFieldKey(i); C+T
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if(header!=null) P'`r  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \_lod kf  
Utility.log(header+" : "+con.getHeaderField(header)); Rj4|Q:XG  
else cJrmm2.0kD  
break;  -4
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} >(;{C<6|^  
} /oriW;OF  
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public void splitterStop() E160A5BTx  
{ Vv ?-"\Z>  
bStop = true; Ry'= ke  
} _A=$oVe  
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)gMG#>up@  
} ~P@Q7T*  
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8|" XSN  
/* ;A*`e$  
**FileAccess.java :3I@(k\PY  
*//文件访问(定位，写) #Y4=J 6  
package NetFox; 1~PV[2a  
import java.io.*; ZSG
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9<>wIl*T`  
}b-g*dn]5  
public class FileAccessI implements Serializable{ 9pX&ZjYP-  
,]d,-)KX8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 f`;j:O  
RandomAccessFile oSavedFile; o}$EG  
long nPos; bdc&1I$  
s#WAR]x0x  
bLwAXW2K+  
public FileAccessI() throws IOException iB498t  
{ 3J5!oF{H  
this("",0); 'JRvP!]  
} `tn{ei  
D8xmE2%  
1A\OC  
public FileAccessI(String sName,long nPos) throws IOException H(Z88.OM  
{ MerFZd 1  
oSavedFile = new RandomAccessFile(sName,"rw"); Gy6l<:;  
this.nPos = nPos; } x2DT8u  
oSavedFile.seek(nPos); fc |GArL#}  
} aL&n[   
o:_Xv.HRZo  
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public synchronized int write(byte[] b,int nStart,int nLen) fyByz=pl  
{ P3=W|81e  
int n = -1; ,=#F//  
try{ BYMi6wts  
oSavedFile.write(b,nStart,nLen); o<|P9#(U"  
n = nLen; }3OKC2K~  
} W;,C_  
catch(IOException e) s[w6FXt  
{ ;oc&Hb  
e.printStackTrace (); "\3B^ e,  
} "t~  
;oy-#p>N%  
])nPPf  
return n; Y4v|ko`l%  
} OR;uqV@  
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} %y@Hh=  
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[m|YWT=  
/* ~4 `5tb  
**SiteInfoBean.java U15H@h  
*/ uLWh|
  
package NetFox; E(Z8  
mD^jd+  
w.?:SD  
public class SiteInfoBean { WjlZ6g2i  
/N&CaH\;^$  
a+%6B_|\  
private String sSiteURL; //Site's URL :(M(>4t  
private String sFilePath; //Saved File's Path 
"CI=`=  
private String sFileName; //Saved File's Name !0vG|C;'  
private int nSplitter; //Count of Splited Downloading File u
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lc~%=  
public SiteInfoBean() d2H|LMhJ  
{//nSplitter的缺省值为5 2fWTY0  
//default value of nSplitter is 5 `wDl<[V  
this("","","",5); ,uSQNre\j  
} -@0GcUE:r  
x3o]U)^  
9f<MQ6_UU  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }<9cL'  
{ TzNn^ir=HX  
sSiteURL= sURL; $3s@}vLd  
sFilePath = sPath; '*"vkgN  
sFileName = sName; NnT1X;0W  
this.nSplitter = nSpiltter; =*r])Vg^  
CnG+Mc^  
3_MS.iM  
} fmb} 2h  
!qM=a3  
^h"`}[+  
public String getSSiteURL() `Ch9~*p  
{ Q+W1lv8R  
return sSiteURL; LC'{p  
} !BOY@$Y  
}MH0L#Tu  
)|DM~%$QM  
public void setSSiteURL(String value) `s8{C b=}1  
{ nv~%#|v_W  
sSiteURL = value; g.zEn/SM  
} =9fajRFTt  
f (F)1  
".<DAs j  
public String getSFilePath() aPm`^ q  
{ ,v';>.]  
return sFilePath; $**r(HV  
} Ljx(\Cm  
d ysC4DS  
'U\<IL#U  
public void setSFilePath(String value) &QGdLXOn  
{ b"vv>Q~U  
sFilePath = value; !3*(N8_|#  
} [&#/]Ul'  
3< 2}V  
aD=A^ktx  
public String getSFileName() SU/BQ3  
{ *rIk:FehLB  
return sFileName; ;3B1_vo9  
} NqDHCI  
vM*($qpAy  
q@nP}Pv&5  
public void setSFileName(String value) ~e+\k>^eN  
{ >U]C/P[+  
sFileName = value; tm#nUw  
} 'VlDh`<W  
4:dH]  
q&W[j5E  
public int getNSplitter() "3)4vuX@;c  
{ XbD4:i%  
return nSplitter; ^`)) C;  
} &iA?+kV  
+KvU$9Ad>  
RHO(?8"_  
public void setNSplitter(int nCount) 2E)wpgUc?e  
{ dVi!Q@y+  
nSplitter = nCount; jO1r)hw N>  
} CB/D4j;  
} 9Bw|(J  
5 ({t4dm  
.MJofE;Jn  
/* ^wc"&;=c|  
**Utility.java EuyXgK>g  
*/ OG~6L4"  
package NetFox; <F`>,Pm  
G}:lzOlMH  
m6[0Kws&  
public class Utility { Od%"B\  
O0pDd4)"  
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public Utility() #7q7PYG4  
{ i5K[>5  
@++.F
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1M 781  
} ZGYr$C~  
O2f-5Y$@  
//线程睡眠 &'}/f5s|  
public static void sleep(int nSecond) >V*mr{/1  
{ l33Pm/V2?  
try{ O^^C;U@U<1  
Thread.sleep(nSecond); Q^e}?v%=%3  
} Y<Fz)dQo  
catch(Exception e) {O`w,dMOI  
{ '4|-9M3f  
e.printStackTrace (); }9W4"e2)  
} ?l^1 *Q,  
} w6W}"Uw  
/|eA9 ]  
//日志 jg\Z;_!W  
public static void log(String sMsg) ZfgJ.<<  
{  s8rE$  
System.err.println(sMsg); $}jssnoU  
} YtfVD7m  
<F=xtyl7  
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public static void log(int sMsg) T3pmVl  
{ Ou1JIxZ)|  
System.err.println(sMsg); K
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} ,H19`;Q  
} G6FEp`  
XAe%m
^  
kZerKP  
/* iMP]W_  
**TestMethod.java ^WNrGF  
*/ }t%!9hr5D  
package NetFox; /S(zff[at  
vbD{N3p)?n  
YGPy@-,E  
public class TestMethod { 5wh|=**/  
(C@~3!AVa  
,]cD  
public TestMethod() Hqn#yInA7~  
{ ///xx/weblogic60b2_win.exe \,7}mdQSv  
try{ Tny%7xSx1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FZtfh  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %e(z/"M=`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6N;wqn  
fileFetch.start(); -OA?BEQ=I  
} 0#S W!b|%  
catch(Exception e){e.printStackTrace ();} K?zH35f$  
)l[M Q4vWW  
;Mpy#yIU.  
} $W9{P;  
$[/&74#0HX  
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public static void main(String[] args) HsHB!mQV  
{ j.L-{6_s>~  
new TestMethod(); Ffv`kn@  
} PUBWZ^63  
} 0 rXxRQ  
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