http断点续传简单实现（java)

/* \f(Y:}9  
**SiteFileFetch.java }FPM-M3y  
*/ 2BHKS-J*  
package NetFox; 9v~1We;{$  
import java.io.*; [O=W>l  
import java.net.*; p QluGIX0V  
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public class SiteFileFetch extends Thread { A)8rk_92Q  
/^w"' '  
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SiteInfoBean siteInfoBean = null; //文件信息Bean VR"u*  
long[] nStartPos; //开始位置 +.w[6  
long[] nEndPos; //结束位置 ~6p5H}'H1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 KzV.+f  
long nFileLength; //文件长度 mHKJ  
boolean bFirst = true; //是否第一次取文件 #`/bQ~
s  
boolean bStop = false; //停止标志 >f>V5L%1  
File tmpFile; //文件下载的临时信息 ^>-+@+( r  
DataOutputStream output; //输出到文件的输出流 .+OB!'dDK^  
-:MmSeG7gO  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） C?,*U  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,ohmc\*J  
{ (I[s3EnhS  
siteInfoBean = bean; \H^;'agA  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2zhn`m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @9aGz6k+  
if(tmpFile.exists ()) ?fV?|ZGZ
I  
{ 7m\vRMK  
bFirst = false; <P-$RX  
read_nPos(); E-^2"j>o  
}  m;c3Z-  
else Y,'%7u  
{ fTcY"A,2  
nStartPos = new long[bean.getNSplitter()]; /N>} 4Ay  
nEndPos = new long[bean.getNSplitter()]; `g--QR  
} !:3^ hb  
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} %y
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public void run() s"WBw'_<<  
{ z|I0-1tAK  
//获得文件长度 9
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//分割文件 D*QYKW=)  
//实例FileSplitterFetch H'Nq#K  
//启动FileSplitterFetch线程 +pz}4M`  
//等待子线程返回 W!91tzs:  
try{ \%TyrY+`K  
if(bFirst) z6I%wh  
{ V#L'7">VP  
nFileLength = getFileSize(); 6Cv.5Vhx  
if(nFileLength == -1) f0DK>L  
{ -%,"iaO  
System.err.println("File Length is not known!"); N'QqJe7Z  
} QD$Gw-U-l=  
else if(nFileLength == -2) %m`zWg-  
{ RkA8  
System.err.println("File is not access!"); 5$%XvM  
} M?$ZJ-  
else dxCPV6 XI  
{ |cgui  
for(int i=0;i<nStartPos.length;i++) 8Q=ZH=SQK  
{ 6e.[,-eU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hF>u)%J/S  
} YG`?o  
for(int i=0;i<nEndPos.length-1;i++) gi$XB}L+X  
{ RgZOt[!.  
nEndPos = nStartPos[i+1]; >g}G}=R~3  
}
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nEndPos[nEndPos.length-1] = nFileLength; ix&'0IrX*  
} J+ts  
} y' [LNp V  
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//启动子线程 /iG7MC\`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; j_GBH8`  
for(int i=0;i<nStartPos.length;i++) 5FOqv=6S  
{ e.8$ga{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?JXa~.dA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wxdyF&U n  
nStartPos,nEndPos,i); B(,:haAr  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +TSSi em  
fileSplitterFetch.start(); ].mqxf  
} FFvCi@oT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,b|-rU\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +>tUz D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #{PmNx%M  
nEndPos = " + nFileLength); tJU-<{8  
// fileSplitterFetch[nPos.length-1].start(); Bp_wnd  
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bRsTBp;R`I  
//等待子线程结束 c^9tYNn  
//int count = 0; tC)6  
//是否结束while循环 DNP@A4~  
boolean breakWhile = false; |5MbAqjzC  
#*^+F?o,(  
6q/?-Qcy  
while(!bStop) 93o;n1
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{ J2M(1g)t9  
write_nPos(); mYv(R!37'  
Utility.sleep(500); tSHFm-q`  
breakWhile = true; :YO@_  
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for(int i=0;i<nStartPos.length;i++) @S3f:s0~D
 
{ +!yXTC  
if(!fileSplitterFetch.bDownOver) QG3&p<  
{ |J>WC}g@n  
breakWhile = false; #b)e4vwCq  
break; l"pN90B4  
} }NCL>l;q  
} dh -,E  
if(breakWhile) ,o#kRWRG  
break; \".^K5Pm  
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//count++; "484n/D  
//if(count>4) D E/:['  
// siteStop(); u8L$]vOg  
} `/IKdO*!S  
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System.err.println("文件下载结束！"); 0C$vS`s&  
} md Gwh7/3  
catch(Exception e){e.printStackTrace ();} .*/Fucr  
} #"*e+.j[;  
nt :N!suP3  
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//获得文件长度 svhI3"
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public long getFileSize() _aS;!6b8W  
{ :k=mzO<&  
int nFileLength = -1; 5/0j}_pP  
try{ }IaA7f  
URL url = new URL(siteInfoBean.getSSiteURL()); 47>>4_Hz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c-4STPNQi  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7/IlL  
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int responseCode=httpConnection.getResponseCode(); K\?]$dK5  
if(responseCode>=400) uaPx"  
{ ~/#1G.H  
processErrorCode(responseCode); *%FA:Y  
return -2; //-2 represent access is error
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} b1?xeG#  
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String sHeader; E,[xUz"  
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for(int i=1;;i++) @mQ:7-,~  
{ I/J7rkf  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r7mD{0s*  
//Utility.log(in.readLine()); cntco@  
sHeader=httpConnection.getHeaderFieldKey(i); 0#p/A^\#7M  
if(sHeader!=null) y'C-[nk  
{ 6sfwlT  
if(sHeader.equals("Content-Length")) R W/z1  
{ TD@v9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ki]ti={12  
break; rSXzBi{  
} 8MwK.H[U  
} 6QQfQ,  
else >!6JKL~=  
break; uZjC c M  
} |UnUG  
} 3,X/,'  
catch(IOException e){e.printStackTrace ();} E2wz(,@  
catch(Exception e){e.printStackTrace ();} ~%k?L4%  
mu]as: ~  

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Utility.log(nFileLength); E>jh"|f:{  
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return nFileLength; }WLh8i?_  
} V>-b`e  
sYSLmUZ{  
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//保存下载信息（文件指针位置） : esg(  
private void write_nPos() LaFZ?7@|}  
{ m!n/U-^  
try{ (t^n'V  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ut@RGg+f8  
output.writeInt(nStartPos.length); N3BL3:@O  
for(int i=0;i<nStartPos.length;i++) OR6ML-|  
{ UPU+ver  
// output.writeLong(nPos); -Yi,_#3{  
output.writeLong(fileSplitterFetch.nStartPos); kh$_!BT  
output.writeLong(fileSplitterFetch.nEndPos); . RVVWqW  
} Qq& W3  
output.close(); ='?:z2lJ  
} oih5B<&f#  
catch(IOException e){e.printStackTrace ();} zk_Eb?mhwV  
catch(Exception e){e.printStackTrace ();} =JLh?Wx  
} R9vT[{!i  
9Ru;`  
IE~%=/|  
//读取保存的下载信息（文件指针位置） cV K7  
private void read_nPos() j-@kW'K  
{ ,Dmc2D  
try{ <z+:j!~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %hS|68pN6  
int nCount = input.readInt(); Ue:z1p;g  
nStartPos = new long[nCount]; e9pOisZ;8  
nEndPos = new long[nCount]; 6SM:x]`##,  
for(int i=0;i<nStartPos.length;i++) I_)*)d44_  
{ 83~ i:+;  
nStartPos = input.readLong(); ZM#=`k9  
nEndPos = input.readLong(); k
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} j|fd-<ng  
input.close(); ]DG?R68DQ  
} .Ce8L&cU  
catch(IOException e){e.printStackTrace ();} |
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catch(Exception e){e.printStackTrace ();} I+ l%Sn#\  
} K<sCF[  
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private void processErrorCode(int nErrorCode) q0mOG^  
{ :PYtR  
System.err.println("Error Code : " + nErrorCode); sRHA."A!8  
} o}Cq.[G4
k  
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1$lh"fHU  
//停止文件下载 8y';\(;  
public void siteStop() m`?MV\^  
{ i8X`HbmN  
bStop = true; %GEJnJ  
for(int i=0;i<nStartPos.length;i++) )vB2!H/  
fileSplitterFetch.splitterStop(); #C*8X+._y  
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} {U!St@  
} WP**a Bp  
//负责部分文件的抓取 dj6*6qX0'^  
**FileSplitterFetch.java ?dZt[vAMn  
*/ 7Du1RuxP  
package NetFox; ~:Uwg+]j  
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import java.io.*; 1M3%fW  
import java.net.*; th5g\h%j*  
YA(@5CZ  
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public class FileSplitterFetch extends Thread { %i0?UpA  
,"}Rg1\4t  
lb'Cl3H  
String sURL; //File URL "$HbK @]!h  
long nStartPos; //File Snippet Start Position w2(guL($  
long nEndPos; //File Snippet End Position a@d=>CT$  
int nThreadID; //Thread's ID #b0{#^S:  
boolean bDownOver = false; //Downing is over $WQq?
1.9  
boolean bStop = false; //Stop identical v0*N)eqDGd  
FileAccessI fileAccessI = null; //File Access interface `ejUs]SR  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g\A y`.s  
{ eHg3}b2r  
this.sURL = sURL; ^ ?hA@{T/1  
this.nStartPos = nStart; '8FC<=+p[  
this.nEndPos = nEnd; cX!Pz.C  
nThreadID = id; s0UFym8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 t6N*6ld2b  
} 7[v%GoE  
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public void run() DR9: _  
{ G1T^a>tj4  
while(nStartPos < nEndPos && !bStop) -7>)i  
{ ri~<~oB2:  
i?;r7>  
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try{ ;a"q'5+Ne  
URL url = new URL(sURL); )(Iy<Y?#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V% TH7@y  
httpConnection.setRequestProperty("User-Agent","NetFox"); l":c  
String sProperty = "bytes="+nStartPos+"-"; OIb  
httpConnection.setRequestProperty("RANGE",sProperty); 2R-A@UE2  
Utility.log(sProperty); d?idTcgs  
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InputStream input = httpConnection.getInputStream(); )+I.|5g  
//logResponseHead(httpConnection); >PKBo  
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byte[] b = new byte[1024]; yWPIIWHx!  
int nRead; 2 mjV
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "pxzntY|  
{ :)f7A7:;  
nStartPos += fileAccessI.write(b,0,nRead); ,n,RFa  
//if(nThreadID == 1) jPvDFT^d/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fr6^
nDY  
} pI+!92Z  
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Utility.log("Thread " + nThreadID + " is over!"); 9D\4n  
bDownOver = true; _gNz9$S  
//nPos = fileAccessI.write (b,0,nRead); PrQ?PvA<L  
} Y>."3*^  
catch(Exception e){e.printStackTrace ();} K?x,T8<aW  
} bte~c  
} l|`9:H  
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//打印回应的头信息 I&9S;I$  
public void logResponseHead(HttpURLConnection con) 2],_^XBvB  
{ S&C1TC  
for(int i=1;;i++) TjK{9A  
{ !M<{E*  
String header=con.getHeaderFieldKey(i); FxG7Pk+=  
if(header!=null) Bc-yxjsw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 07T70[G  
Utility.log(header+" : "+con.getHeaderField(header)); X#a`K]!B  
else Nb2Qp K  
break; Rr(* aC2P  
} hw_JDv+  
} {MAQ/5  
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public void splitterStop() jg 2qGC  
{ :^ i9]  
bStop = true; p_*M:P1Ma4  
} RIM`omM  
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} $h9='0Wi0'  
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\ A1uhHP!  
/* >4m'tZ8  
**FileAccess.java #yseiVm;  
*//文件访问(定位，写) FFhtj(hVgc  
package NetFox; _fFU#k:MU  
import java.io.*; I|oT0y&  
+1C3`0(  
1:C:?ZC#c  
public class FileAccessI implements Serializable{ ?q`0ZuAg\<  
r#PMy$7L  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 D8{D[fJ;  
RandomAccessFile oSavedFile; Eu}b8c  
long nPos; 3>ex5  
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D\~zS`}  
public FileAccessI() throws IOException CDj~;$[B  
{ Mpue   
this("",0); _R|Ify#J  
} v7  
#H [Bb2(j  
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public FileAccessI(String sName,long nPos) throws IOException ,y`CRlr:  
{ ,ea^,H6  
oSavedFile = new RandomAccessFile(sName,"rw"); 1[F3 Z  
this.nPos = nPos; 2N#$X'8  
oSavedFile.seek(nPos); zr v]  
} 6dH }]~a  
! hd</_#  
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public synchronized int write(byte[] b,int nStart,int nLen) ?,P3)&3g  
{ 2Q7R6*<N:  
int n = -1; 'XQ`g CF=  
try{ ] H~4  
oSavedFile.write(b,nStart,nLen);  @4d)R  
n = nLen; }UJv[  
} 'k;4j|<  
catch(IOException e) _CBWb  
{ rVvR!"//yH  
e.printStackTrace (); A,CW_  
} CQ7{1,?2  
{%)s.5Pfw  
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return n; DBLk!~IF  
}  ~I/@i  
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} N- e$^pST  
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/* kh~'Cn "O  
**SiteInfoBean.java spU)]4P&  
*/ @J{m@ji{  
package NetFox; WH ?}~u9  
m^'uipa\  
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public class SiteInfoBean { !Bz0^1,L  
1XG!$4DW  
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private String sSiteURL; //Site's URL rn DCqv!'P  
private String sFilePath; //Saved File's Path ERwHLA  
private String sFileName; //Saved File's Name WPZ?*Sx  
private int nSplitter; //Count of Splited Downloading File Ze<K=Q%(i  
_(J&aY\  
s?8<50s  
public SiteInfoBean() G6V
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{//nSplitter的缺省值为5 4?N8R$  
//default value of nSplitter is 5 s}5cSU!|  
this("","","",5); T|&[7%F3"  
} w6`9fX6{h  
f>BWG`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) '65LKD  
{ q'pK,uNW  
sSiteURL= sURL; ld$i+6|   
sFilePath = sPath; (SSRY9  
sFileName = sName; Uax+dl  
this.nSplitter = nSpiltter; =b;>?dP  
R+gz<H.Q  
5cx#SD&5/  
} 2r$#m*  
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public String getSSiteURL() TW !&p"Us+  
{ FP[!BUOf"  
return sSiteURL; kd"N29  
} :JlP[I  
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t6v/sZ{F  
public void setSSiteURL(String value) RN=` -*E1  
{ d1[ZHio2c?  
sSiteURL = value; z;@*r}H  
} zB yqD$  
5zON}"EC  
Vh>Z,()>>@  
public String getSFilePath() UGK*Gy  
{ :[;hu}!&  
return sFilePath; 6q 2_WX  
} E7-@&=]v  
Z`YJBcXR  
VK@!lJu!  
public void setSFilePath(String value) `~eUee3b.~  
{ U`hY{E;  
sFilePath = value; 2wF8 P)  
} SwZA6R&  
ON+J>$[[  
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public String getSFileName() ^pHq66d%Z  
{ 1?Z4K/  
return sFileName;
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} _V`DWR *  
Uix6GT;  
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public void setSFileName(String value) ?7{H|sI
 
{ `p+Zz"/  
sFileName = value; Agrk|wPK  
} )=Jk@yj8x  
%D *OO{  
&r:7g%{n  
public int getNSplitter() 43=,yz2Ef  
{ D= 7c(  
return nSplitter; 23gPbtq/  
} 3po:xMY  
%j7XEh<'  
-lv)tHs<  
public void setNSplitter(int nCount) o=1
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{ -IV]U*4  
nSplitter = nCount; 0V?F'<qy  
} 63A}TBC  
} #KO,~]k5|e  
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ZK)%l~J  
/* c/
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**Utility.java ]LM-@G+Jz  
*/ Q%f|~Kl-hd  
package NetFox; i7ly[6{^pr  
yDGVrc'  
{^N[("`  
public class Utility { ,UuH}E  
N;[>,0&z  
aCL!]4K84$  
public Utility() {%C7EAq*  
{ ,GgAsj
: K  
9VbOQ{8  
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} h?pkE  
'g{9@PkGn  
//线程睡眠 ZIF49`Y4TF  
public static void sleep(int nSecond) J4\qEO  
{ bAx?&$  
try{ `[n("7,  
Thread.sleep(nSecond); }C|dyyr  
} *Aa?yg:=  
catch(Exception e) wKsT7c'  
{ /S lYm-uQ+  
e.printStackTrace (); of@#:Qs  
} ]EpWSs!"g  
} R,Vd.-5M  
y.Z?LCd<  
//日志 1u9LdkhnY  
public static void log(String sMsg) 'f?$"U JF  
{ >&U,co$>  
System.err.println(sMsg); M^]cM(swK5  
} ]H1I,`=@  
S)/_muP  
T'b_W,m~,u  
public static void log(int sMsg) 5;{H&O9Q  
{ ~b2wBs)r  
System.err.println(sMsg); STaA]i}P  
} c[ ]4n  
} .?hP7;hhI  
jXMyPNTK  
k{Aj^O3gD  
/* AoI/n4T^  
**TestMethod.java Ny%(VI5:  
*/ Y(cGk#0  
package NetFox; `9b7>Nn<  
.>IhN 5  
J":,Vd!*-  
public class TestMethod { IyLx0[:U  
8M`#pN^  
G"XVn~]  
public TestMethod() <|Pun8j  
{ ///xx/weblogic60b2_win.exe I}vmU^Y>  
try{ 7?%k7f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .?Gd'Lp  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `WH"%V:"Q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _}En/V_  
fileFetch.start(); v3jg~"!  
} fOMW"myQ  
catch(Exception e){e.printStackTrace ();} iS<I0\D  
JQ@E>o7_  
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} ]h5Yg/sms  
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jWE:ek*  
public static void main(String[] args) >M/V oV  
{ "PpN0Rr  
new TestMethod(); /Dj=iBO  
} k|H:  
} `p;I}  
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