http断点续传简单实现（java)

/*
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**SiteFileFetch.java U<**Est  
*/ 9Kw4K#IqQ  
package NetFox; 6<+R55  
import java.io.*; ->x+
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import java.net.*; *
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public class SiteFileFetch extends Thread { >WMH.5p  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =j 6amk-  
long[] nStartPos; //开始位置 ,>n 4 `A  
long[] nEndPos; //结束位置 9N|O*h1;u  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 lM C4j  
long nFileLength; //文件长度 w8*+l0  
boolean bFirst = true; //是否第一次取文件 nn"!x|c  
boolean bStop = false; //停止标志 Pq~"`-h7:  
File tmpFile; //文件下载的临时信息 P.P3/,  
DataOutputStream output; //输出到文件的输出流 }> k9]Y  
0s:MEX6w|  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） yOGaW~  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1sZwW P  
{ \Nu(+G?e  
siteInfoBean = bean; m,v"N%k,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]`&EB~K&NY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lNQt  
if(tmpFile.exists ()) ~wIVw}  
{ !'Xk=+  
bFirst = false; ?'p`Qv  
read_nPos(); 0 ]U ;5  
} |]~tX zY  
else |HJdpY>Uu  
{ n8Jx;j  
nStartPos = new long[bean.getNSplitter()]; kssS,Ogf\_  
nEndPos = new long[bean.getNSplitter()]; }%[TJ@R;  
} B=#rp*vwL  
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} %up]"L&i  
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public void run() XRKL;|cd  
{ ~" B0P>7  
//获得文件长度 ~d ~$fR  
//分割文件 XQ--8G  
//实例FileSplitterFetch KP[ax2!x  
//启动FileSplitterFetch线程 oDTt+b  
//等待子线程返回 +q"d=  
try{ CN\SxK`,  
if(bFirst) x SF#ys4v  
{ gAC}  
nFileLength = getFileSize(); b{s_cOr/  
if(nFileLength == -1) P*T'R  
{ Z,qo jtw  
System.err.println("File Length is not known!"); 3Tg  
} tfvX0J  
else if(nFileLength == -2) 2J^6(vk  
{ j./3)  
System.err.println("File is not access!"); /d9I2~}B  
} S3i%7f^C?N  
else BHOxwW{  
{ Cq?l>  
for(int i=0;i<nStartPos.length;i++) FEw51a+V  
{ 6*gMG3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !`hjvJryw  
} t=NPo+fm  
for(int i=0;i<nEndPos.length-1;i++) ^q_0(Vf  
{ pvQw+jX  
nEndPos = nStartPos[i+1]; ;&37mO/T  
} 1Z6<W~,1OM  
nEndPos[nEndPos.length-1] = nFileLength; BJ<hP9#  
} \eH~1@\S  
} n'v[[bmu  
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//启动子线程 v#@"Evh7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ZwB< {?  
for(int i=0;i<nStartPos.length;i++)  @D^y<7(  
{ [94A?pn[z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Jm0P~E[n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), hU3c;6]3  
nStartPos,nEndPos,i); 6C4c
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AIR,XlD  
fileSplitterFetch.start(); =21$U[  
} /@X!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B BbGq8p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d }=fJ  
nEndPos = " + nFileLength); 6x)7=_:0  
// fileSplitterFetch[nPos.length-1].start(); ynvU$}w ~'  
I?uU}
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//等待子线程结束 ~m8".Z"  
//int count = 0; G|Rsj{2'  
//是否结束while循环 E^rKS&P
 
boolean breakWhile = false; H=9kDP${  
)=;GQ*<8Zs  
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while(!bStop) nICc}U?k  
{ U>w#`Sy[  
write_nPos(); U(P^-J<n1  
Utility.sleep(500); 1fm4:xHH  
breakWhile = true; JFH3)Q  
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for(int i=0;i<nStartPos.length;i++) pYf57u  
{ _8A  
if(!fileSplitterFetch.bDownOver) (RVe,0y  
{ M<^]Ywq*p  
breakWhile = false; e+6mbJ7y  
break; @&?E3?5ll  
} )UbPG`x8  
} O42`Z9oK  
if(breakWhile) WD#
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break; SQ
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//count++; q\s"B.(G"  
//if(count>4) #(swVo:+E  
// siteStop(); h ` qlI1]  
} b.I_  
W
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System.err.println("文件下载结束！"); scX'>\w&c  
} pHQrjEF*  
catch(Exception e){e.printStackTrace ();} "Vh3hnS~  
} F t/yPv  
$B%wK`J  
,ZGU\t  
//获得文件长度 ICck 0S!  
public long getFileSize() /]j^a:#"6t  
{ ~,ZU+  
int nFileLength = -1; P.bxq50  
try{ JLd-{}A""-  
URL url = new URL(siteInfoBean.getSSiteURL()); Gyx4}pV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /tm2b<G  
httpConnection.setRequestProperty("User-Agent","NetFox"); n(I,pF  
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int responseCode=httpConnection.getResponseCode(); a-e_
q  
if(responseCode>=400) "I)/|x\G*  
{ V>Dqw!  
processErrorCode(responseCode); ^h\(j*/#X  
return -2; //-2 represent access is error #[f]-c(!  
} :eIi^K z[  
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String sHeader; }1fi
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for(int i=1;;i++) '0-YFx'U0V  
{ wZ4w`|'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); QB uX#bDV  
//Utility.log(in.readLine()); I(<9e"1O  
sHeader=httpConnection.getHeaderFieldKey(i); QPX&P{!g  
if(sHeader!=null) cwuzi;f  
{ >``sM=Wat  
if(sHeader.equals("Content-Length")) BG|
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{ \?v?%}x  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); W4;/;[/L  
break; GCf,Gfmr  
} vA3wn><  
} dx@|M{jz'  
else Mj&G5R~_  
break; s$%t2UaV  
} Hr_5N,  
} {V,aCr  
catch(IOException e){e.printStackTrace ();} azz=,^U#  
catch(Exception e){e.printStackTrace ();} |\zzOfaO  
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Utility.log(nFileLength); Y5CDdn  

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return nFileLength; SR$ 'JGfp  
} p}oGhO&=  
/4*Y#IpZ  
2FR+Z3&z  
//保存下载信息（文件指针位置） Xh}S_/9}5  
private void write_nPos() lZAXDxhnT  
{ =oBlUE  
try{ rD+mI/_J`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); VV;%q3}:  
output.writeInt(nStartPos.length); _ amP:h  
for(int i=0;i<nStartPos.length;i++) {J1iheuS}  
{ %afN&T  
// output.writeLong(nPos); hkb&]XWi[  
output.writeLong(fileSplitterFetch.nStartPos); 9tX+n{i  
output.writeLong(fileSplitterFetch.nEndPos); Zg$S% 1(Q  
} i;rcgd  
output.close(); mC0_rN^Aj  
} #f [}a  
catch(IOException e){e.printStackTrace ();} t"zi'9$t  
catch(Exception e){e.printStackTrace ();} 4O{G^;  
} !&xci})7a  
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//读取保存的下载信息（文件指针位置） lA%FS]vh  
private void read_nPos() | C^.[)  
{ k#bG&BF  
try{ FDFwx|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <UF0Xc&X'  
int nCount = input.readInt(); iC3C~?,
7  
nStartPos = new long[nCount]; |Fz ^(US  
nEndPos = new long[nCount]; [^Bjmw[7  
for(int i=0;i<nStartPos.length;i++) QChncIqc  
{ Q 0G5<:wc  
nStartPos = input.readLong(); gu6%$z  
nEndPos = input.readLong(); ^,0Lr$+  
} lb$_$+@Vr  
input.close(); GE`1j'^-  
} &|j0GP&  
catch(IOException e){e.printStackTrace ();} CT5s`v!s  
catch(Exception e){e.printStackTrace ();} N>Ih2>8t  
} W]oa7
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private void processErrorCode(int nErrorCode) CuD}Uo+u  
{ O wuc9  
System.err.println("Error Code : " + nErrorCode); &r.M~k >  
} ; PncJe5
x  
:hT.L3n,  
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//停止文件下载 %ufh  
public void siteStop() "={*0P  
{ ]J[d8S5  
bStop = true; S)g:+P  
for(int i=0;i<nStartPos.length;i++) Fgi`g{N  
fileSplitterFetch.splitterStop(); }K8e(i6z  
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} d)S`.Q  
} RyP MzxV  
//负责部分文件的抓取 !ej]'>V,X  
**FileSplitterFetch.java O2\(:tvw  
*/ ~Th,<w*o  
package NetFox; mogmr  
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import java.io.*; 9Vqy<7i1  
import java.net.*; >s
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public class FileSplitterFetch extends Thread { YGC%j  
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String sURL; //File URL xu_,0ZT]{  
long nStartPos; //File Snippet Start Position
'B{FRK  
long nEndPos; //File Snippet End Position 3:MJKS02OD  
int nThreadID; //Thread's ID 5VP0Xa ~  
boolean bDownOver = false; //Downing is over ;}iB9 Tl  
boolean bStop = false; //Stop identical ff5 gE'  
FileAccessI fileAccessI = null; //File Access interface z~X/.>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y] c1x=x  
{ |ZE^'e*k  
this.sURL = sURL; &oMWs]0  
this.nStartPos = nStart; En1LGi4#  
this.nEndPos = nEnd; u -P !2vT  
nThreadID = id; RYA@{.O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !b7"K|  
} }dop]{RG  
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public void run() y/y~<-|<@  
{ D/f4kkd  
while(nStartPos < nEndPos && !bStop)
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{ DrKB;6  
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try{ iX6>u4~(  
URL url = new URL(sURL); Vn4wk>b}$2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :u./"[G  
httpConnection.setRequestProperty("User-Agent","NetFox"); GE(~d'  
String sProperty = "bytes="+nStartPos+"-"; 3PGAUQR#"q  
httpConnection.setRequestProperty("RANGE",sProperty); _<LL@IX  
Utility.log(sProperty); @U18Dj[  
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InputStream input = httpConnection.getInputStream(); eFG(2OVg}M  
//logResponseHead(httpConnection); Q8%_q"C  
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byte[] b = new byte[1024]; o^vX\a?`u  
int nRead; E Izy  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .dk<?BI#H  
{ 7Vsp<s9bj  
nStartPos += fileAccessI.write(b,0,nRead); A$3Rb
n}"  
//if(nThreadID == 1) IO)#O<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m9oOH5@K~  
} H:]cBk^[,  
{?eUAB<  
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Utility.log("Thread " + nThreadID + " is over!"); 3}<U'%sd  
bDownOver = true; zk FX[-'O  
//nPos = fileAccessI.write (b,0,nRead); N=BG0t$  
} (_zlCHB  
catch(Exception e){e.printStackTrace ();} *$g!/,  
} k_L`  
} GeTk/tU  
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//打印回应的头信息 uy'seJ  
public void logResponseHead(HttpURLConnection con) Ztg_='n  
{ 9Q%lS  
for(int i=1;;i++) s:}?rSI  
{ 'ZW(Hjrd  
String header=con.getHeaderFieldKey(i); }I&.xzJ  
if(header!=null) Mg.%&vH\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); N!7}B  
Utility.log(header+" : "+con.getHeaderField(header)); iyl i/3|  
else RkYn6  
break; :.,9}\LK  
} ]alc%(=  
} t`
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public void splitterStop() cdt9hH`Cd  
{ l,7& z  
bStop = true; p0bWzIH  
} kun/KY  
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&.,K@OFE}  
} zHb[.ry~  
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<  
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/* ki9&AFs2X  
**FileAccess.java !k)6r6  
*//文件访问(定位，写) yov~'S9  
package NetFox; ^ ~Eh+  
import java.io.*; F'Y ad  
cRVL1ne  
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public class FileAccessI implements Serializable{ 1IA1
;  
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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 vd4@jZ5  
RandomAccessFile oSavedFile; ,Y/B49  
long nPos; AU$~Ap*rsa  
[yXmnrxA  
2'Dl$DH  
public FileAccessI() throws IOException HrBJi  
{ a/j;1xcc<  
this("",0); F3}MM dX  
} {h?pvH_>  
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public FileAccessI(String sName,long nPos) throws IOException  l(?B0  
{ etr-\Cp  
oSavedFile = new RandomAccessFile(sName,"rw"); b# N"}-\^  
this.nPos = nPos; jmID@37t  
oSavedFile.seek(nPos); 32[}@f2q  
} KdR4<qVV}  
h=7q;-@7  
b_31\  
public synchronized int write(byte[] b,int nStart,int nLen) vFVUdxPOw  
{ zFq%[X  
int n = -1; N-M.O:p  
try{ Tn}`VW~  
oSavedFile.write(b,nStart,nLen); 6h;(b2p{  
n = nLen; 8)X9abC  
} Jj-\Eb?  
catch(IOException e) 5?k5J\+  
{ <k:I2LF_  
e.printStackTrace (); I\.|\^  
} 5naFnm7%  
1Z# $X`  
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return n; LTWkHyx  
} !DZ=`a?y  
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} y&NqVR=  
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/t0L%jJZ  
/* j<t3bM-G  
**SiteInfoBean.java kamQZzPe  
*/ )d2Z g  
package NetFox; 1B~O!']N<  
>v:ex(y0  
ra$:ibLN  
public class SiteInfoBean { PJ.\)oP  
E]@&<TFq  
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private String sSiteURL; //Site's URL Cr5ND\  
private String sFilePath; //Saved File's Path 4[gmA  
private String sFileName; //Saved File's Name !#KKJ`uB"  
private int nSplitter; //Count of Splited Downloading File ku]5sd >b  
cc[(w #K  
]Y\$U<YjO  
public SiteInfoBean() d51lTGH7Z  
{//nSplitter的缺省值为5 <Vhd4c  
//default value of nSplitter is 5 G^c,i5}w  
this("","","",5); v Y[s#*+  
} jrib"Bh3,  
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9-42A7g^C  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F9r.DG$}  
{ &6x(
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sSiteURL= sURL; '}Fe&%  
sFilePath = sPath; yfG;OnkZ  
sFileName = sName; 46:<[0Psl/  
this.nSplitter = nSpiltter; uH[WlZ4  
aCG rS{  
+4?Lwp'q  
} {iD/0q  
<]
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public String getSSiteURL() ZJ/528Ju  
{ J>Ar(p  
return sSiteURL; LDt6<D8,Q  
} $plk>Khg  
fs!dI  
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public void setSSiteURL(String value) C]L)nCOBX  
{ hfwJZ\_60  
sSiteURL = value; )CFJXc:  
} >XgoN\w
 
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.(@=L1C<}J  
public String getSFilePath() UsE\p9mCuV  
{ WyO*8b_ D  
return sFilePath; (!}N&!t  
} G+ /Q!ic  
,>j3zjf^  
7'\.QJ!<  
public void setSFilePath(String value) 'Ea3(OsuXn  
{ fCY|iO0.t  
sFilePath = value; #w{`6}p  
} I{IB>j}8  
'.|}  
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public String getSFileName() lx`?n<-X  
{ _^<vp  
return sFileName; Cd%5XD^  
} , 'pYR]3  
L ]')=J+  
KXPCkNIN!  
public void setSFileName(String value) i2qN 0?n  
{ ?0Q3F  
sFileName = value; ;As~TGiT  
} %S312=w  
C @Ts\);^  
3qWrSziD  
public int getNSplitter() }i+C)VUX   
{ {Ydhplg{  
return nSplitter; lS=YnMs6a  
} <-`bWz=+  
:,8y8z$+  
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public void setNSplitter(int nCount) ioi/`iQR  
{ wkt4vE87  
nSplitter = nCount; qCI&H7u@  
} [MeivrJ+  
} t#(NfzN  
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/* lU1SN/'zx  
**Utility.java e@hPb$7  
*/ C >Oe
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package NetFox; 0]>bNbLB"  
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=-dnniKW4  
public class Utility { DFr$2Y3H  
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public Utility() lO@-*m$  
{ qZ<n\Mt  
(Q{JI~P  
e{8C0=  
}  V FM[-  
?c.\\2>|F  
//线程睡眠 HVM%B{(  
public static void sleep(int nSecond) I(6%'s2  
{ cC8$oCR?  
try{ ihkZs3}  
Thread.sleep(nSecond); Gb^63.}  
} i3 js'?7E  
catch(Exception e) ZRhk2DA#FF  
{ )=)N9CRy  
e.printStackTrace (); &^ERaPynd  
} B} qRz  
} orJ|Q3c)d  
hTBJ
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//日志 ]Jz=.F sO  
public static void log(String sMsg) ` k] TOc  
{ &tOo[U?  
System.err.println(sMsg); 9^Xndo]y  
} +9HU&gQ3  
U'jmgHq  
-n:2US<  
public static void log(int sMsg) %[n5mF*`  
{ C5=^
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System.err.println(sMsg); )F9IzR-&m  
} Qe~C}j%  
} #|\|G3Si %  
WGV]O|  
{Lju7'5L  
/* 3\2&?VAjR  
**TestMethod.java >(:3H+  
*/ 55v=Ij?M  
package NetFox; TrDTay  
 o]0E  
.Z7tE?  
public class TestMethod { ,5 8-h?B0v  
T:j41`g%s  
i(A`'V8GY  
public TestMethod() <,Gjo]z  
{ ///xx/weblogic60b2_win.exe %YxKWZ/?  
try{ u9_?c G-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IlEU6Rs  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [<+T
@"y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >u%Bn\G  
fileFetch.start(); @kd$.7Y9  
} s\.r3U&6  
catch(Exception e){e.printStackTrace ();} 2zo>`;l  
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S*r }oX0  
} n(A;:)W{  
+46& Zb35  
i%
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public static void main(String[] args) Ps! \k%FUl  
{ Pw6l'  
new TestMethod(); s2sJJdN  
} !le#7Kii  
} El}~3|a?  
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