http断点续传简单实现（java)

/* 8K@e8p( y  
**SiteFileFetch.java :QF`Orb!^  
*/ KpIY>k  
package NetFox; fm$Qd^E|e  
import java.io.*; !^EA}N.u  
import java.net.*; Ffd4c  
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public class SiteFileFetch extends Thread { )LNKJe+  
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!=HxL-`j  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3BAQ2S}  
long[] nStartPos; //开始位置 A8k$.E  
long[] nEndPos; //结束位置 k@pEs# a  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 t*fH&8(  
long nFileLength; //文件长度 3EH@tlTl  
boolean bFirst = true; //是否第一次取文件
qW /&.  
boolean bStop = false; //停止标志 Nrq/Pkmy  
File tmpFile; //文件下载的临时信息 A"0Yn(awWu  
DataOutputStream output; //输出到文件的输出流 D~TlG@Pq  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,Xg^rV~]  
public SiteFileFetch(SiteInfoBean bean) throws IOException (,|eE)+  
{ Bc`L]<  
siteInfoBean = bean; b!`6s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); YDZB$?&a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c[;A$P= 8.  
if(tmpFile.exists ()) xiL+s-  
{ 'Hgk$Im+  
bFirst = false; /`t}5U>S_  
read_nPos(); 0X$2~jV>  
} =iB$4d2  
else ;Zc0
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{ qxcTY|&  
nStartPos = new long[bean.getNSplitter()]; k2.\1}\  
nEndPos = new long[bean.getNSplitter()]; C>F5=&  
} 1(Z+n,Hh  
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} =4L%A=]`  
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public void run() /7ShE-.5#  
{ F&Rr&m  
//获得文件长度 uL:NWgN  
//分割文件 e;LC\*dG  
//实例FileSplitterFetch vP_mS 4X  
//启动FileSplitterFetch线程 Xc&J.Tw#4*  
//等待子线程返回 'Tskx  
try{ LoSrXK~0~J  
if(bFirst) LMN`<R(q]  
{ YRv}w3yQ  
nFileLength = getFileSize(); QWWI  
if(nFileLength == -1) crx%;R  
{ |QQ(1#d  
System.err.println("File Length is not known!"); rl2(DA{  
} Y1F%-o  
else if(nFileLength == -2) I|2dV9y  
{  Y=H_U$  
System.err.println("File is not access!"); .bRtK+}F#  
} E 0OHl  
else jw/@]f;N  
{ 
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for(int i=0;i<nStartPos.length;i++) ezhfKt]j  
{ `=kiqF2P}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PG@C5Rnu  
} 7\H_9o0$  
for(int i=0;i<nEndPos.length-1;i++) P,7R/-u5D  
{ uLfk>&hc  
nEndPos = nStartPos[i+1]; i?V:+0#q\]  
} b/tcD r  
nEndPos[nEndPos.length-1] = nFileLength; 0IHAoV60  
} \5a;_N[Ed  
} @y6^/'  
U.=TjCW  
U} 
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//启动子线程 mi@uX@
#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; iszVM  
for(int i=0;i<nStartPos.length;i++) feM(  
{ 07\]8^/G  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bn=7$Ax  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f:AfMf>m  
nStartPos,nEndPos,i); 9niffq)h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tiRi_  
fileSplitterFetch.start(); J/rF4=j%xy  
} <"S`ZOn  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j9}.U \  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); BFqM6_/J  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H2+V1J=  
nEndPos = " + nFileLength); -k%|sqDZj  
// fileSplitterFetch[nPos.length-1].start(); _^$F^}{&  
?\<Kb|Q  
zs'Jgm.v  
//等待子线程结束 H1 i+j;RN  
//int count = 0; f'tQLF[r<  
//是否结束while循环 Z}IuR|=  
boolean breakWhile = false; +O8}twt@  
Y$fF"pG?  
 {+gK\N
z  
while(!bStop) )/z+W[t  
{ %wGQu;re  
write_nPos(); :>jzL8  
Utility.sleep(500); ;0Ih:YY6  
breakWhile = true; L9l]0C37e  
6kONuG7Yv  
`:dGPBBO  
for(int i=0;i<nStartPos.length;i++) }{[p<pU$C  
{ ++!0r['+>  
if(!fileSplitterFetch.bDownOver) sD6vHX%  
{ KPZqPtb;  
breakWhile = false; ,8DjQz0ZPo  
break; "ER=c3 t  
} J6nH|s8  
} ~!e(e2  
if(breakWhile) N0YJ'.=8,  
break; awLSY:JI  
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u~Y+YzCxV  
//count++; V9;IH<s:  
//if(count>4) Vp8!-[R  
// siteStop(); _1jeaV9@  
} K~qKr<)  
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System.err.println("文件下载结束！"); l HZ4N{n  
} -(E-yCu  
catch(Exception e){e.printStackTrace ();} 1V]j8  
} 9 vNz yh\  
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//获得文件长度 ZCDXy  
public long getFileSize() cejD(!MKe  
{ Fl\kt.G  
int nFileLength = -1; Ujvk*~:  
try{ b\xse2#  
URL url = new URL(siteInfoBean.getSSiteURL()); b^<7@tY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J& D0,cuk  
httpConnection.setRequestProperty("User-Agent","NetFox"); Nu><r  
3IoN.  
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int responseCode=httpConnection.getResponseCode(); 3\|PwA9fN8  
if(responseCode>=400) f/Q/[2t  
{ prGp/"E  
processErrorCode(responseCode); zKf0 :X  
return -2; //-2 represent access is error zH *7
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} Xs)?PE[   
)!sjXiC!h  
py\/
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String sHeader; wNl "y  
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for(int i=1;;i++) ,(kaC.Em  
{ J^mm"2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bFfDaO<k  
//Utility.log(in.readLine()); D ~NWP%H  
sHeader=httpConnection.getHeaderFieldKey(i); K` <`l  
if(sHeader!=null) p8z"Jn2P  
{ ho6,&Bp8  
if(sHeader.equals("Content-Length")) k-$J #  
{ c`#4}$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); oXGP6#  
break; ,"T[#A~  
} ^C{?LH/2  
} 9}11>X  
else 6/|"y  
break; ]iaQD _'\  
}
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} r6e!";w:U  
catch(IOException e){e.printStackTrace ();} ZRC7j?ui8`  
catch(Exception e){e.printStackTrace ();} 4Gsq)i17j  
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Utility.log(nFileLength); "IoY$!Hk  
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return nFileLength; ,.,Y{CP  
} V V Aw y6  
9<*<-x{A17  
<}AmzeHr+  
//保存下载信息（文件指针位置） OJ}aN>k  
private void write_nPos() mtNB09E(  
{ %?z;'Y7D  
try{ L$}'6y/@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); oRl@AhS  
output.writeInt(nStartPos.length); @Hst-H.l<l  
for(int i=0;i<nStartPos.length;i++) +/Vzw  
{ C] |m|`  
// output.writeLong(nPos); $)7Af6xD  
output.writeLong(fileSplitterFetch.nStartPos); 2spK#0n.HV  
output.writeLong(fileSplitterFetch.nEndPos); CfHPJ:Qo[  
} 'h{DjNSM  
output.close(); _B\X&!G.  
} V(n3W=#kky  
catch(IOException e){e.printStackTrace ();} N{fYO4O  
catch(Exception e){e.printStackTrace ();} Y1 6pT  
} =L}$#Y8?  
OC2%9Igx0  
s9BdmD^|#  
//读取保存的下载信息（文件指针位置） _P{v=`]Eu  
private void read_nPos() @%#!-wC-5  
{ yx/qp<=  
try{ ^4>Icz^ F  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); b'4r5@GO  
int nCount = input.readInt(); Td![Id  
nStartPos = new long[nCount]; 'Ie
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nEndPos = new long[nCount]; -o sxKT:  
for(int i=0;i<nStartPos.length;i++) .t{?doOT  
{ v5`Odbc=w  
nStartPos = input.readLong(); Tq5F'@e  
nEndPos = input.readLong(); A;Uw b  
} Py#iC#g~  
input.close(); IV$2`)[A&X  
} X[o"9O|<  
catch(IOException e){e.printStackTrace ();} ps=QVX)YP  
catch(Exception e){e.printStackTrace ();} g?!;04  
} Mer\W6e"e  
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private void processErrorCode(int nErrorCode) 2)>Ty4*  
{ LY(h>`  
System.err.println("Error Code : " + nErrorCode); z
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} |c!lZo/  
7.xJ:r|  
Px
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//停止文件下载 pXHeUBY.  
public void siteStop() &E8fd/s=k  
{ Hxd^oE  
bStop = true; 8__C T  
for(int i=0;i<nStartPos.length;i++) 4$b9<:M_  
fileSplitterFetch.splitterStop(); .@]M'S^1  
^b(>Bg)T  
}@wXm  
} DR#[\RzNI  
} ?8)$N  
//负责部分文件的抓取 Dv+:d4|"  
**FileSplitterFetch.java `z3"zso  
*/ BcD%`vGJ  
package NetFox; e\>g@xE%  
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f= l*+QY8f  
import java.io.*; U*em)/9  
import java.net.*; Voc&T+A m  
&0S/]E`_M  
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public class FileSplitterFetch extends Thread { ;:pd/\<  
8rsv8OO  
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String sURL; //File URL &b&o];a  
long nStartPos; //File Snippet Start Position &,@wLy^T  
long nEndPos; //File Snippet End Position vR"<:r47?  
int nThreadID; //Thread's ID hTbot^/  
boolean bDownOver = false; //Downing is over t9 m],aH  
boolean bStop = false; //Stop identical esQRg~aCGy  
FileAccessI fileAccessI = null; //File Access interface _a=f.I  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y7#4Mcc`~  
{ a'ODm6#  
this.sURL = sURL; I UxsvW+  
this.nStartPos = nStart; b(H)8#C  
this.nEndPos = nEnd; A'X, zw^}  
nThreadID = id; n;Etn!4M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cZXra(AD  
} !4G<&hvb  
H=k*;'  
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public void run() & A<Pf.Us  
{ ;F<)BEXC<  
while(nStartPos < nEndPos && !bStop) h8_~ OX  
{ ' ! ls"qo  
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try{ c F(]`49(  
URL url = new URL(sURL); JP<Z3 A2q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~0>{PD$@  
httpConnection.setRequestProperty("User-Agent","NetFox"); l?%U*~*  
String sProperty = "bytes="+nStartPos+"-"; !Rw\k'<GKX  
httpConnection.setRequestProperty("RANGE",sProperty); (&u)FB*  
Utility.log(sProperty); m=<;)  
XL7jUi_4:L  
&c!=< <5M  
InputStream input = httpConnection.getInputStream(); @*c) s_  
//logResponseHead(httpConnection); "ci<W_lx  
'Kj8X{BSFb  
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byte[] b = new byte[1024]; 5&r2a}K  
int nRead; $wn"+wX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4q<:% 0M|  
{ XJ;JDch  
nStartPos += fileAccessI.write(b,0,nRead); \lleO|m  
//if(nThreadID == 1) D:HeP:.I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cNG6 A4  
} 2v<[XNX  
b#C"rTw  
4&/-xg87(  
Utility.log("Thread " + nThreadID + " is over!"); f(E  'i>  
bDownOver = true; rXz,<^Hmj  
//nPos = fileAccessI.write (b,0,nRead); Ucnit^,  
} !Jj=H()}  
catch(Exception e){e.printStackTrace ();} ? I}T[j  
} z {J1pH_X  
} a;
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//打印回应的头信息 A4?_0:<  
public void logResponseHead(HttpURLConnection con) &~Q ?k  
{ JPk3T.qp  
for(int i=1;;i++) C6eon4Ut  
{ LV 94i  
String header=con.getHeaderFieldKey(i); !m1pL0  
if(header!=null) "t"=9:_t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L$x/T3@  
Utility.log(header+" : "+con.getHeaderField(header)); `#X{
.  
else ";
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break; $sO}l  
} 7j&l2Z  
} <_H0Q_/(  
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YAZ=-@]`\  
public void splitterStop() bct&ge7YX  
{ [M2,bc8SJV  
bStop = true; <..%@]+  
} f|FQd3o)  
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} }~-)31e'`  

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' n~N*DH  
/* h3xX26l  
**FileAccess.java 4#=!VK8ZH  
*//文件访问(定位，写) Xb3vvHdI  
package NetFox; eeb8v:4  
import java.io.*; ^LT9t2  
.?S#DS )  
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public class FileAccessI implements Serializable{ xMhR;lKY  
YKl!M/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 uW[s?  
RandomAccessFile oSavedFile; ^m8\fCA*  
long nPos; VkhK2  
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public FileAccessI() throws IOException 7!JoP?!  
{ h2aJa@;S  
this("",0); Ok({Al1A,w  
} 60AX2-sdJ,  
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#>ci!4Gz=Z  
public FileAccessI(String sName,long nPos) throws IOException 7qXgHrr0|U  
{ &"C1XM  
oSavedFile = new RandomAccessFile(sName,"rw"); %v~j10e  
this.nPos = nPos; 7X}_yMxc  
oSavedFile.seek(nPos); (DKpJCx  
} J(/ eR,ak  
oRWsi/Zf  
>cMU<'&  
public synchronized int write(byte[] b,int nStart,int nLen) S^D ~A8u  
{ _W#27I  
int n = -1; 05pCgI}F>  
try{ Z@C D1+G  
oSavedFile.write(b,nStart,nLen); s9`T%pg  
n = nLen; R?|_`@@A  
} N}FG%a  
catch(IOException e) !FpMO`m  
{ 4 <]QMA0
 
e.printStackTrace (); 
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} cS ];?tqrA  
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return n; aeBth{  
} 4VU5}"<  
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} oHi&Z$#!n  
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/* W+K=M*^D;c  
**SiteInfoBean.java &*)tqQeQf  
*/ BTd'bD~EA  
package NetFox; LK:|~UV?  
6gR=e+  
[[s k  
public class SiteInfoBean { Y?%6af+  
4a2&kIn  
KP<J~+_ik  
private String sSiteURL; //Site's URL @Qc['V)  
private String sFilePath; //Saved File's Path qo. 6T  
private String sFileName; //Saved File's Name p-(Z[G*  
private int nSplitter; //Count of Splited Downloading File /{kyjf[o&*  
*=|i"
 
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public SiteInfoBean() ;_Rx|~!!  
{//nSplitter的缺省值为5 1@nR.v"$  
//default value of nSplitter is 5 p6HZ2Q:a  
this("","","",5); ?pF;{  
} \ I?;%  
x(=kh%\;  
XIp9=jhSR  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1 yzxA(  
{ @JEr/yy  
sSiteURL= sURL; HK[sHB&
 
sFilePath = sPath; aF;&#TsB  
sFileName = sName; Spk
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this.nSplitter = nSpiltter; %r
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} KT g$^"\  
/p%K[)T(  
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public String getSSiteURL() q]r!5&Z  
{ QKP9*dz  
return sSiteURL; k=~?!+p7  
} \W(p)M  
pKH4?F  
\ qs6%  
public void setSSiteURL(String value) W#lvH=y  
{ f^%E]ki  
sSiteURL = value; -91l"sI  
} y2qESAZ%k}  
SY$%!! @R  
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public String getSFilePath() 3,F/i+
@  
{ mm{U5
  
return sFilePath; AQiP2`?  
} - 5k4vx N}  
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public void setSFilePath(String value) "=".ne  
{ ]Z84w!z  
sFilePath = value; 
}DM2#E`_  
} =:g^_Hy  
hx2C<;s4  
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public String getSFileName() gOWyV@  
{ mhVoz0%1X  
return sFileName; @"/
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} KqSa"76R  
P5d@-l%}  
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public void setSFileName(String value) ?}]kIK}MC  
{ 7O9s5  
sFileName = value; f C^l9CRY  
} pS<b|wu?f  
$3[cBX.=  
#y*=UV|h  
public int getNSplitter() @NHRuk+  
{ &=?`;K  
return nSplitter; m+m6"yE#_  
} \Zh)oUHd  
__V]HcP;  
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F:
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public void setNSplitter(int nCount) D}061~zb$  
{ eFnsf}(Iy  
nSplitter = nCount; R^2Uh$kk{A  
} "{Bek<  
} o5D"<-=>  
H4m6H)KOG  
23f[i<4e  
/* PPqTmx5S  
**Utility.java j^ _I{  
*/ 3N bn|_`(  
package NetFox; <{U{pC
T%  
Fm;)7.% >  
@\DD|o67  
public class Utility { Ad,r(0a LZ  
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public Utility() epR~Rlw>2  
{ )PG,K4z  
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} ];I|_fXo%  
KyyG8;G%  
//线程睡眠 ,Mhe:^3  
public static void sleep(int nSecond) gZjO
lp  
{ ob] lCX)  
try{ ii;WmE&  
Thread.sleep(nSecond); |tg?b&QR  
} {a3kn\6H0  
catch(Exception e) ZmULy;{<)  
{ `Q&]dE=  
e.printStackTrace (); &1p8#i  
} bNROXiX  
} Vf?#W,5>=  
t>wxK ,  
//日志 Lmwh`oOl  
public static void log(String sMsg) ;ULC|7rL  
{ ' 4~5ez|:  
System.err.println(sMsg); )KqR8UO
  
} X}*o[;2G  
aVP|:OAj  
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public static void log(int sMsg) Hk]BC
 
{ tqQ0lv^J  
System.err.println(sMsg); hf<$vRti>  
} UPKi/)C;  
} 7rSUSra  
W"kw>JEt  

VM]IL%AN  
/* vs1Sh?O  
**TestMethod.java s3-ktZ@  
*/ >fye^Tx  
package NetFox; >'6GcnEb4.  
7I(t,AK
J  
%;Z bQ9  
public class TestMethod { |)qK g  
kP)o=\|W{z  
Z) Xs;7  
public TestMethod() 8'lhp2#h  
{ ///xx/weblogic60b2_win.exe B/=q_.1F>  
try{ C|f7L>qe  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \5P.C  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qu~|d}0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RW7oL:$dt  
fileFetch.start(); c[ony:6  
} =$8@JF'  
catch(Exception e){e.printStackTrace ();} [S]!+YBK  
mY`]33??v  
HqdJdWl#"  
} {(OIu]:  
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4$aO;Z_  
public static void main(String[] args) z@~&Kwf\}  
{ >C3NtGvy  
new TestMethod(); atf%7}2  
} |.C    
} U+;>S$  
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