http断点续传简单实现（java)

/* 9M01}  
**SiteFileFetch.java d2X#_(+d  
*/ _,Fwt  
package NetFox; >>^c_0"O  
import java.io.*; oF,8j1  
import java.net.*; (:T~*7/"  
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public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean y ImriCT  
long[] nStartPos; //开始位置 sMO3eNLn  
long[] nEndPos; //结束位置 _\o +9X!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @Gn9x(?J  
long nFileLength; //文件长度 B)^]V<l(w  
boolean bFirst = true; //是否第一次取文件 yMz@-B  
boolean bStop = false; //停止标志 U7x}p^B9\N  
File tmpFile; //文件下载的临时信息 G2L7_?/m  
DataOutputStream output; //输出到文件的输出流 a.8nWs^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Za}91z"  
public SiteFileFetch(SiteInfoBean bean) throws IOException  ITbl%q  
{ k,v.U8  
siteInfoBean = bean; l^0 <a<P  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :syR4A WM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \D}/tz5~B  
if(tmpFile.exists ()) c1n? @L  
{ 7CG_UB  
bFirst = false; |Z2_1( ku  
read_nPos(); Ld`~^<B  
} )XO2DY1/&  
else R!$j_H  
{ _TX.}167;-  
nStartPos = new long[bean.getNSplitter()]; |y'q`cY  
nEndPos = new long[bean.getNSplitter()]; s 6hj[^O  
} MF E%q  
i,RK0q?>  
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* 5P/&*c|  
} s_1]&0<  
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public void run() )UJ]IB-Q|1  
{ .2Rh_ful  
//获得文件长度 i1G}mYz_  
//分割文件 (4c<0<"$  
//实例FileSplitterFetch UJ6WrO5#kB  
//启动FileSplitterFetch线程 NWNgh/9?  
//等待子线程返回 i!,>3  
try{ ![Jxh,f  
if(bFirst) *2@q=R-1  
{ <,cDEN7  
nFileLength = getFileSize(); 8@$QN4^u^  
if(nFileLength == -1) $rjv4e}7  
{ @[JQCQ#r  
System.err.println("File Length is not known!"); jJ?3z,h  
} LQ{4r1,u]  
else if(nFileLength == -2) {ZfTUt)-P  
{ <w,aS;v6jp  
System.err.println("File is not access!"); +qS$t  
} $W0lz#s:  
else _wHqfj)  
{ 7CQ48LH]  
for(int i=0;i<nStartPos.length;i++) jliKMd<?  
{ Tp0Tce/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 92} ,A`=  
} ZGp8$Y>r  
for(int i=0;i<nEndPos.length-1;i++) Y+G4:  
{ Bq$bxuhV  
nEndPos = nStartPos[i+1]; cc^V~-ph  
} OK2wxf  
nEndPos[nEndPos.length-1] = nFileLength; e|kYu[^  
} m*I
5 \  
} a{u)~:/G  
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]
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//启动子线程 ^|gN?:fA}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =CqLZ$10  
for(int i=0;i<nStartPos.length;i++) @P@t/  
{ FNm8j#c~Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g\jdR_/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >eU;lru2Q  
nStartPos,nEndPos,i); XVI+Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); +$<m;@mZ  
} *?i~AXJm  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n ~ =]/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); n$~RgCf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _|s{G  
nEndPos = " + nFileLength); 2KPXRK  
// fileSplitterFetch[nPos.length-1].start(); 8ztY_"]3p  
&i!.6M2  
fd)}I23Q'  
//等待子线程结束 ;xj
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//int count = 0; 02=eE|Y@  
//是否结束while循环 Zo&U3b{Dy  
boolean breakWhile = false; Cjwg1?^RZ  
F!N
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while(!bStop) IXC: Q  
{ 7qnw.7p  
write_nPos(); Xt$?Kx_,  
Utility.sleep(500); p_mP'
  
breakWhile = true; O"{NHNG\oT  
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for(int i=0;i<nStartPos.length;i++) KWd]?e)  
{ :KW   
if(!fileSplitterFetch.bDownOver) &0N 3 p  
{ y|1-,u.$  
breakWhile = false; $osDw1C  
break; i*F^;-q)  
} 3tgct <"  
} tF=96u_X  
if(breakWhile) -o=qYkyLK  
break; OvQG%D}P=  
'jfI1 ]q  
a7M8sZ?"  
//count++; iXXgPapz  
//if(count>4) JZai{0se  
// siteStop(); 9v/1>rziE  
} ON!1lS  
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System.err.println("文件下载结束！");  H'2pmwk  
} $e0sa=/  
catch(Exception e){e.printStackTrace ();} 
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} t&-7AjS5  
[,lBY-Kz+  
! 5]/2  
//获得文件长度 ]Wfnpqc^  
public long getFileSize() hGzj}t W8d  
{ 0naegy?,  
int nFileLength = -1; l$z-'  
try{ V<(cW'zA/  
URL url = new URL(siteInfoBean.getSSiteURL()); M`S >Q2{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NO;+:0n  
httpConnection.setRequestProperty("User-Agent","NetFox"); B6|=kl2C  
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int responseCode=httpConnection.getResponseCode(); >a]{q^0  
if(responseCode>=400) X$J  
{ d+z8^$z"  
processErrorCode(responseCode); OCF=)#}qd  
return -2; //-2 represent access is error a^|mF# z  
} 0urQA_JC  
o
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,@(lYeD
"  
String sHeader; z!?xz  
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for(int i=1;;i++) h\:"k_u#  
{ 7!z0)Ai_>=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !~PV\DQN  
//Utility.log(in.readLine()); vr2tMD  
sHeader=httpConnection.getHeaderFieldKey(i); W!htCwnkF  
if(sHeader!=null) .y|*  
{ A)'{G  
if(sHeader.equals("Content-Length")) PC=b.H8P+W  
{ Ptn0;GC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /_>S0  
break; $xNZ.|al  
} G4]T  
} Qp]V~s(  
else arRbq!mO  
break; ZC@Pfba[`  
} kwWDGA?zFB  
} S0du,A~  
catch(IOException e){e.printStackTrace ();} arET2(h  
catch(Exception e){e.printStackTrace ();} r ",..{  
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Utility.log(nFileLength); 2I>X]r.S!1  
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return nFileLength; $CRu?WUS]'  
} l*":WzRGvF  
g-Vxl|hR  
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//保存下载信息（文件指针位置） sA#}0>`3S  
private void write_nPos() ^#KkO3  
{ _?CyKk\I  
try{ >-0Rq[)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ;y/&p d+  
output.writeInt(nStartPos.length); xo a1='  
for(int i=0;i<nStartPos.length;i++) 3c}@_Yn  
{ f;x0Ho5C2  
// output.writeLong(nPos); Jx!#y A;  
output.writeLong(fileSplitterFetch.nStartPos); YZMSiDv[e  
output.writeLong(fileSplitterFetch.nEndPos); xG/B$DLn  
} `zwXfY,%  
output.close(); kZ>_m&g  
} X@RS /  
catch(IOException e){e.printStackTrace ();} [+ Kjun_  
catch(Exception e){e.printStackTrace ();} _ VKBzOH  
} C6Lc  
=;ClOy9  
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//读取保存的下载信息（文件指针位置） )[+82~F  
private void read_nPos() ";yey]  
{ Py y!B  
try{ tp*.'p-SI  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :m]H?vq] \  
int nCount = input.readInt(); OD]`oJ|  
nStartPos = new long[nCount]; J}BN}|Y@2  
nEndPos = new long[nCount]; X6*4IE  
for(int i=0;i<nStartPos.length;i++) <hvs{}TS  
{ Ra)wlIx  
nStartPos = input.readLong(); %<8`(Uu5  
nEndPos = input.readLong(); SMoJKr(:w#  
} ' Dcj\=8
 
input.close(); #9zpJ
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} y)vK=,"  
catch(IOException e){e.printStackTrace ();} /#jH#f[  
catch(Exception e){e.printStackTrace ();} 6I2`oag  
} 0Q?)?8_  
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private void processErrorCode(int nErrorCode) & 6'Rc#\P  
{ {ppzg
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System.err.println("Error Code : " + nErrorCode); FJ,"a%m/Q  
} }C4wED.  
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6~c#G{kc  
//停止文件下载 ,_iq$I;  
public void siteStop() iR?}^|]  
{ !6!Gx:  
bStop = true; Co>e<be%S  
for(int i=0;i<nStartPos.length;i++) M8nfbc^  
fileSplitterFetch.splitterStop(); VKV :U60  
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} d|?Xo\+  
} UodBK7y  
//负责部分文件的抓取 !7Eodq-0  
**FileSplitterFetch.java ;/:Sx/#s  
*/ $vrkxn  
package NetFox; c+D<  
wXjidOd$  
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import java.io.*; e,
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import java.net.*; \~RDvsSD  
WP2=1"X63  
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public class FileSplitterFetch extends Thread { DA1?M'N  
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o?Aj6fNY?  
String sURL; //File URL Z1#u&oX  
long nStartPos; //File Snippet Start Position 2ah%,o  
long nEndPos; //File Snippet End Position Mg#yl\v  
int nThreadID; //Thread's ID I4W@t4bZ  
boolean bDownOver = false; //Downing is over !O,Sq/=.  
boolean bStop = false; //Stop identical o]EL=j  
FileAccessI fileAccessI = null; //File Access interface vJLGy]  
c {/J.  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >H^#!eaqw  
{ e2f+Fv 9  
this.sURL = sURL; {`QA.he.  
this.nStartPos = nStart; W1 k]P.  
this.nEndPos = nEnd; )adV`V%=>  
nThreadID = id; q`,%L1c4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [Ur\^wS  
} Y{D%v  
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public void run() P#O2MiG  
{ f(Y_<%  
while(nStartPos < nEndPos && !bStop) /a'1W/^2  
{ N0H=;CIQ  
V"m S$MN  
^|H={pd'c0  
try{ #l ZK_N|1x  
URL url = new URL(sURL); N+'j on}U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _Ao$)Gu)  
httpConnection.setRequestProperty("User-Agent","NetFox"); "$XX4w M  
String sProperty = "bytes="+nStartPos+"-"; %Yj%0  
httpConnection.setRequestProperty("RANGE",sProperty); -QroT`gy  
Utility.log(sProperty); 3V<@Vkf5  
.4p3~r?=S  
AH|gI2  
InputStream input = httpConnection.getInputStream(); @^A
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//logResponseHead(httpConnection); =hkYQq`Q  
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byte[] b = new byte[1024]; 1>"-!ADm  
int nRead; !bP%\)5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "!~o  
{ ,
;_+o]  
nStartPos += fileAccessI.write(b,0,nRead); )P$|9<_q7x  
//if(nThreadID == 1) tO&ffZP8$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v8)"skVnFG  
} CuWJai:nQ;  
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Utility.log("Thread " + nThreadID + " is over!"); gxN>q4z  
bDownOver = true; L-T,[;bl  
//nPos = fileAccessI.write (b,0,nRead); DcW?L^Mst  
} <.Ws; HN}  
catch(Exception e){e.printStackTrace ();} 1Y|a:){G  
} j-":>}oW2.  
} yd).}@  
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GC{M"q|_  
//打印回应的头信息 V5w1ET  
public void logResponseHead(HttpURLConnection con) Nob(D'vSr  
{ {drc}BL_  
for(int i=1;;i++) 5~|{:29X  
{ Snx!^4+MF  
String header=con.getHeaderFieldKey(i); X H-_tvB  
if(header!=null) HeOdCr-PN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D5TDg\E  
Utility.log(header+" : "+con.getHeaderField(header)); gcU*rml  
else 2yZr!Rb~*  
break; "f,{d}u  
} T.4&P#a1  
} m1l6QcT1  
U[@y8yN6M  
CIjc5^Y2  
public void splitterStop() `ePC$Ovn  
{ 0f^{Rp6  
bStop = true; jN\u
}!\O  
} Cf 2@x  
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} %2?+:R5.  
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/* p;O%W
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**FileAccess.java 5% 2A[B  
*//文件访问(定位，写) }yz>(Pq  
package NetFox; V ~C$|+>e  
import java.io.*; ffZ~r%25{  
5E&#Kh(I  
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public class FileAccessI implements Serializable{ qN $t_  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c$O8Rhx  
RandomAccessFile oSavedFile; ,o&C"sb  
long nPos; S#7YJ7 K"N  
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public FileAccessI() throws IOException <$A,Ex94  
{ c0qp-=^&.  
this("",0); -8Jw_  
} CM;b_E)9)f  
=p+y$  
!%iHJwS#  
public FileAccessI(String sName,long nPos) throws IOException E TT46%Y  
{ (W ~K1]  
oSavedFile = new RandomAccessFile(sName,"rw"); ZK5nN9`  
this.nPos = nPos; S+ kq1R  
oSavedFile.seek(nPos); )cqD">vs  
} g!'R}y  
>|$]=e,Z  
l<6u@,%s  
public synchronized int write(byte[] b,int nStart,int nLen) @(3F4Z.i%.  
{ >f(?Mxh2  
int n = -1; k }=<51c  
try{ kZ40a\9 Ye  
oSavedFile.write(b,nStart,nLen); Zf'*pp T&q  
n = nLen; " kDiK`i  
} J2YQdCL  
catch(IOException e) z3oi(  
{ 3k Ci5C  
e.printStackTrace (); d*gAL<M7E  
} qJhsMo2
IH  
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return n; ag-A}k>v  
} X8nos  
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} yvAO"43  
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/* sV\_DP/l  
**SiteInfoBean.java C]`uC^6g  
*/ *l2`- gbE  
package NetFox; l/eF P  
@~3--  
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public class SiteInfoBean { ,eXtY}E  
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private String sSiteURL; //Site's URL R><g\{G]  
private String sFilePath; //Saved File's Path 8Zv``t61  
private String sFileName; //Saved File's Name uqMw-f/  
private int nSplitter; //Count of Splited Downloading File y.rN(  
(eHyas %X  
@:lM|2:  
public SiteInfoBean() nM,:f)z  
{//nSplitter的缺省值为5 iI3:<j l  
//default value of nSplitter is 5 J2UQq7-y  
this("","","",5); q7R]!zk  
} +$2{u_m,  
S;|:ci<[=  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \br!77  
{ rP@#_(22  
sSiteURL= sURL; p>6`jr  
sFilePath = sPath; O9=/\Kc  
sFileName = sName; ~+q1g[6  
this.nSplitter = nSpiltter; 2MkrVQQ9g  
{e|qQ4~h  
x#rgFY,TY  
} ajYe?z  
9T,/R1N8  
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public String getSSiteURL() H;H=8'  
{ @u~S!(7.Wi  
return sSiteURL; baxZ>KNi  
} nm'l}/Ug  
dC11kqqj  

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public void setSSiteURL(String value) /d`"WK,  
{ pLMt2G  
sSiteURL = value; Sg#XcTG  
} 9}573M  
zWsr|= [  
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public String getSFilePath() jHLs 5%  
{ D=tZ}_'{t  
return sFilePath; $a(-r-_Fi]  
} Zk3Pv0c  
sZ;|NAx)  
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public void setSFilePath(String value) E$8JrL  
{ mxc)Wm<4  
sFilePath = value; Q7%4`_$!  
} kfy!T rf  
j\>LJai"  
.l}Ap7@  
public String getSFileName() ~9X^3.nI  
{ @AyteHK  
return sFileName; <izQ]\kL  
} /{M<FVXK+|  
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&|v)
 
public void setSFileName(String value) h`[$ Bp  
{ ,75)  
sFileName = value; L/3A g* ]  
} .RD<]BxJ  
)6|L]'dsZ  
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public int getNSplitter() "oP^2|${  
{ z;OYPGvkw  
return nSplitter; !avol/*  
} +WX/4_STV  
bO~y=Pa\  
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public void setNSplitter(int nCount) eP{srP3 9  
{ SzULy >e  
nSplitter = nCount; ou,[0B3n0  
} 7DB_Z/uU  
} iFI74COam  
n1[c\1  
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/* )"?4d[ 5  
**Utility.java SV7;B?e%Y  
*/ uF ?[H -y  
package NetFox; Ufr@j` *  
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ggso9ZlLu+  
public class Utility { WBe0^=x  
FO{=^I5YA  
1 ZdB6U0  
public Utility() PKm|?kn{0(  
{ $l.*;h*  
r )|3MUj  
i~B?p[  
} {UiSa'TR1b  
r(,U{bU<  
//线程睡眠 HC`0Ni1  
public static void sleep(int nSecond) sXLW';Fz  
{ >.:+|Br`  
try{ :X2_#qW#C  
Thread.sleep(nSecond); }{0}$#zu  
} F72#vS j  
catch(Exception e) So%X(, |  
{ fN vQ.;  
e.printStackTrace (); )u?f| D  
} 8R~<$xz  
} =lacfPS  
U,GSWMI/K  
//日志 zzmC[,u}  
public static void log(String sMsg) _,3ljf?WQM  
{
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System.err.println(sMsg); Vaxg  
} !-I,Dh-A  
4.A^5J'W  
q^X7x_  
public static void log(int sMsg) 7>hcvML  
{ unDW2#GX  
System.err.println(sMsg); mh+T!v$[n)  
} ew;;e|24  
} 4&)sROjV=  
#qRoTtMq7  
S ?Zh#`(*  
/* s{^98*  
**TestMethod.java  }D1x%L  
*/ G?Et$r7:R  
package NetFox; iFIGJS  
w\C1Bh!  
j?T'N:Qd  
public class TestMethod { 7UT
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uWS]l[Ga  
#*A'<Zm  
public TestMethod() U1`5P!ov  
{ ///xx/weblogic60b2_win.exe J"gMm@#C4  
try{ ~E}kwF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %0\@\fC41  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); HcRw9,I'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); bWyimr&B  
fileFetch.start(); FvT&nb{  
} (Tx_`rO4VY  
catch(Exception e){e.printStackTrace ();} 0aT:Gy
;  
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Y:*% [\R  
} vG|!d+  
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}  
+.cpZqWn3  
public static void main(String[] args) }n)0}U5;0  
{ QE 4  
new TestMethod(); /*C!]Z>.  
} UiU/p
 
} C T~6T&'  
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