http断点续传简单实现（java)

/* T
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**SiteFileFetch.java 'h
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*/ Bib<ySCre  
package NetFox; @e)}#kN.  
import java.io.*; H7X-\K 1w  
import java.net.*; -x+3nb|.  
$(9QnH1KY  
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public class SiteFileFetch extends Thread { ie6c/5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^xa, r#N:V  
long[] nStartPos; //开始位置 mLuNl^)3  
long[] nEndPos; //结束位置 L(TM& ps\-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 fs ufYIf  
long nFileLength; //文件长度 DEZww9T2Qs  
boolean bFirst = true; //是否第一次取文件 z?\it(  
boolean bStop = false; //停止标志 mITB\,,G  
File tmpFile; //文件下载的临时信息 /Sj~lHh  
DataOutputStream output; //输出到文件的输出流 *DPX4P  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \P.h;|u  
public SiteFileFetch(SiteInfoBean bean) throws IOException !kE5]<H\  
{ Cq2Wpu-u  
siteInfoBean = bean; I_<VGUk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]j3>=Jb;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5*%Gh&)  
if(tmpFile.exists ()) (L/>LZn|  
{ N_c44[z1  
bFirst = false; P4[kW}R  
read_nPos();
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} v1:.t  
else N[/<xW~x?4  
{ :oIBJ u%/  
nStartPos = new long[bean.getNSplitter()]; f)*"X[)o
 
nEndPos = new long[bean.getNSplitter()]; [7@g*!+d  
} )aIcA  
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} kG>jb!e@(  
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public void run() 6j6CA?|  
{ h0PDFMM<  
//获得文件长度 wm`<+K  
//分割文件 =p@`bx  
//实例FileSplitterFetch w jkh*Y  
//启动FileSplitterFetch线程 x0<;Rm [u=  
//等待子线程返回 fa/S!%}fO  
try{ {zb'Z Yz  
if(bFirst) .
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{ p1KhI;^  
nFileLength = getFileSize(); #%E`~&[  
if(nFileLength == -1) K{P-+(  
{ uos8Mav{E  
System.err.println("File Length is not known!"); zq};{~u(  
} yLC[-.H  
else if(nFileLength == -2) =?OU^u`C  
{ @Go_5X(  
System.err.println("File is not access!"); ^@^8iZ  
} Z 8rD9 k$6  
else _KH91$iW8m  
{ oV%:XuywT  
for(int i=0;i<nStartPos.length;i++) &O'W+4FAc  
{ jSem/;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +KTfGwKt  
} \L*%?~  
for(int i=0;i<nEndPos.length-1;i++) O)dnr8*  
{ 9lYKG^#D  
nEndPos = nStartPos[i+1]; 8oX1 F(R  
} 9\_s&p=:.  
nEndPos[nEndPos.length-1] = nFileLength; _EMI%P&s  
} C7%R2>}?f  
} roS" q~GS,  
d {!P c<  
|A3"Jc.2o  
//启动子线程 !PA:#]J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; JqzoF}WH  
for(int i=0;i<nStartPos.length;i++) t=P+m  
{ $nE{%?n-#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %%NoXW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), qf0pi&q  
nStartPos,nEndPos,i); #kW=|8X  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f+ r>ur}\)  
fileSplitterFetch.start(); >+%#m'Y&&  
} S\:^#Yi`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .\XRkr'-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); x/s:/YN'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e@h{Ns.1-  
nEndPos = " + nFileLength); lO-DXbgql$  
// fileSplitterFetch[nPos.length-1].start(); KTm^}')C8  
J||g(+H>  
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//等待子线程结束 1mmL`M1  
//int count = 0; )O[8 D  
//是否结束while循环 /!Rva"  
boolean breakWhile = false; ud/!@WG  
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)U\i7[k>  
while(!bStop) !BoGSI  
{ 1`8s
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write_nPos(); Kki(A4;7F  
Utility.sleep(500); 9~UR(Ts}l  
breakWhile = true; ? $B4'wc5  
+~"IF+TRH  
[(n5-#1S  
for(int i=0;i<nStartPos.length;i++) /4r2B.91O  
{ tiZH;t';<  
if(!fileSplitterFetch.bDownOver) 'Dfs&sm  
{ +-!3ruwSn  
breakWhile = false; Z|qI[uiO  
break; 5Dkb/Iagi  
} IUOf/mM5  
} ?T/4 =  
if(breakWhile) =Z+^n ?"  
break; ,l&?%H9q  
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:I#.d7`uk  
//count++; eCI'<^  
//if(count>4) gclj:7U  
// siteStop(); #eJfwc1JY  
} "Da1BuX\  
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:j]6vp6  
System.err.println("文件下载结束！"); aqSOC(jU  
} oywPPVxj  
catch(Exception e){e.printStackTrace ();} m'2F#{  
} hrniZ^  
>M5}L<  
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//获得文件长度 "W5MZ  
public long getFileSize() I!/EQO|  
{ xC< )]  
int nFileLength = -1; KF7w{A){  
try{ EeYL~ORdi  
URL url = new URL(siteInfoBean.getSSiteURL()); Ny"9!3V   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9'(_*KSH  
httpConnection.setRequestProperty("User-Agent","NetFox"); x;
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int responseCode=httpConnection.getResponseCode(); `*U@d%a  
if(responseCode>=400) Apu-9|oP  
{ t3$cX_  
processErrorCode(responseCode); 4<s;xSCL  
return -2; //-2 represent access is error 2[Bbdg[O  
} ](oeMl18R  
tM5(&cQ!d  
S:!5|o|  
String sHeader; 7}xQ4M\u$  
z_(l]Ern}  
}P2*MrkcHB  
for(int i=1;;i++) \B')2phE  
{ -, +o*BP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /,I?"
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//Utility.log(in.readLine()); g;Fdm5Q  
sHeader=httpConnection.getHeaderFieldKey(i); ` ,T.  
if(sHeader!=null) pRfKlTU\  
{ 0faf4LzU!  
if(sHeader.equals("Content-Length")) b$2=w^*  
{ 7UBW3{d/u5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +Vg(2Xt  
break; ,U9j7E<4  
} !wAnsK  
} Q8HNST($?  
else _U*R_2aV  
break; 7'+`vt#E  
} Wda?$3!^q  
} 7_Vd%<:  
catch(IOException e){e.printStackTrace ();} 44QW&qL!(  
catch(Exception e){e.printStackTrace ();} kXV  
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Utility.log(nFileLength); {X,-T&  
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return nFileLength; ?o V.SG'  
} .dzw5R&  
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//保存下载信息（文件指针位置） wOUCe#P|r  
private void write_nPos() $I`,nN  
{ 1q'_J?Xmd  
try{ KXTk.\c  
output = new DataOutputStream(new FileOutputStream(tmpFile)); P3bRv^  
output.writeInt(nStartPos.length); Z+R-}<   
for(int i=0;i<nStartPos.length;i++) x^3K=l;N  
{ 34k(:]56|  
// output.writeLong(nPos); H"+|n2E^  
output.writeLong(fileSplitterFetch.nStartPos); tklS=R^Vn  
output.writeLong(fileSplitterFetch.nEndPos); %.[AZ>  
} \ bNDeA&l  
output.close(); "7alpjwb  
} lS;S:- -F  
catch(IOException e){e.printStackTrace ();} !OV+2suu1  
catch(Exception e){e.printStackTrace ();} M|{KQ3q:9  
} -XECYwTh  
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//读取保存的下载信息（文件指针位置） CNiJuj`  
private void read_nPos() O,@QGUoA  
{ aS3-A4  
try{ #;2mP6a[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cL%eP.  
int nCount = input.readInt(); @6jKjI  
nStartPos = new long[nCount]; ),;h  
nEndPos = new long[nCount]; ;XY#Jl>tg  
for(int i=0;i<nStartPos.length;i++) >taT V_,  
{ $v{sb,  
nStartPos = input.readLong(); qzD  
nEndPos = input.readLong(); vO{[P#L}  
} f$nZogaQ  
input.close(); 1g!%ej jd  
} Y0'~u+KS`5  
catch(IOException e){e.printStackTrace ();} Ft2ZZ<As  
catch(Exception e){e.printStackTrace ();} t I+]x]m+  
} blV'-Al  
c_?!V  
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private void processErrorCode(int nErrorCode) P`hg*"<V  
{ wu0JXB%&^  
System.err.println("Error Code : " + nErrorCode); p'SY 2xq-,  
} XK l3B=h  
mpCKF=KL.  
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//停止文件下载 +]
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public void siteStop() Izfj 9h ?  
{ am WIA`n=  
bStop = true; [0NH#88ym<  
for(int i=0;i<nStartPos.length;i++) vP<8,XG  
fileSplitterFetch.splitterStop(); cRPy5['E  
jK=-L#hz  
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} @n=FSn6
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} n]JfdI  
//负责部分文件的抓取 IW|1)8d  
**FileSplitterFetch.java [VB\T|$  
*/ M\9p-%"L  
package NetFox; vn
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import java.io.*; zQ eXN7$  
import java.net.*; W{'tS{  
m
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public class FileSplitterFetch extends Thread { v/Ei0}e6~  
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String sURL; //File URL QXT*O  
long nStartPos; //File Snippet Start Position EEp,Z`  
long nEndPos; //File Snippet End Position a U*cw
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int nThreadID; //Thread's ID ;lb@o,R :  
boolean bDownOver = false; //Downing is over Q,f5r%A.  
boolean bStop = false; //Stop identical 0jwex  
FileAccessI fileAccessI = null; //File Access interface \\Huk*Jn{  
2}R)0][W  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException szb],)|18  
{ 6cOm8#  
this.sURL = sURL; |N>TPK&Xt  
this.nStartPos = nStart; V-iY2YiR  
this.nEndPos = nEnd; :-.bXOB(  
nThreadID = id; H]W59-{a  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0~XZ  
} bjJ212J  
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public void run() t7DT5SrR  
{ ]^^mJt.Iv  
while(nStartPos < nEndPos && !bStop) Y;XEC;PXD  
{ ]q@6&]9  
) crhF9!4  
2V#(1Hc!  
try{ Ey;uaqt  
URL url = new URL(sURL); f~? MNJ2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F.JvMy3  
httpConnection.setRequestProperty("User-Agent","NetFox"); "o[j'  
String sProperty = "bytes="+nStartPos+"-"; 7fJWb)z!k  
httpConnection.setRequestProperty("RANGE",sProperty); oos7x6  
Utility.log(sProperty); *<_8]C0>  
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InputStream input = httpConnection.getInputStream(); oUBn:Ir@  
//logResponseHead(httpConnection); M1T)e9k=x  
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byte[] b = new byte[1024]; anTS8b   
int nRead; !7-dqw%l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qG%'Lt  
{ x;Jy-hMNl  
nStartPos += fileAccessI.write(b,0,nRead); AA um1xl  
//if(nThreadID == 1) >{^&;$G+*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FHS6
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} Z;QbqMj  
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+mN]VO*y  
Utility.log("Thread " + nThreadID + " is over!"); #yv_Eb02  
bDownOver = true; Vn6g(:\w  
//nPos = fileAccessI.write (b,0,nRead); +idj,J|  
} _$?SKid|o  
catch(Exception e){e.printStackTrace ();} 8I'c83w  
} l(@UpV-  
} M38QA  
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!;^sIoRPV  
//打印回应的头信息 8`*Wl;9u  
public void logResponseHead(HttpURLConnection con) [s4lSGh  
{ {`vF4@  
for(int i=1;;i++) [ENm(e$sI  
{ v'*#P7%Kf  
String header=con.getHeaderFieldKey(i); +tNu8M@xFo  
if(header!=null) VSCOuNSc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); dhW)<  
Utility.log(header+" : "+con.getHeaderField(header)); G:QaWqUb  
else e
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break; eEIa=MB*  
} &oTUj'$  
} ;aip1Df  
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public void splitterStop() Yqy7__vm  
{ bBBW7',[a  
bStop = true; ^|?/ y=  
} vl<W`)'  
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} aCe<*;b@  
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LoQ
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/* C{<qc,!4  
**FileAccess.java @JS O=8  
*//文件访问(定位，写) t8,s]I&  
package NetFox; 4 e1=b,  
import java.io.*; (5] |Kcp|  
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public class FileAccessI implements Serializable{ L<encPJt  
f:gXXigY,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X|)Ox ,(  
RandomAccessFile oSavedFile; )pV5l|`  
long nPos; j()<.h;'  
(-tF=wR,W  
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public FileAccessI() throws IOException o/bmS57  
{ ;H5PiSq;z  
this("",0); q$Z.5EN
 
}
r7r>1W%4  
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#y }{ 'rF?  
public FileAccessI(String sName,long nPos) throws IOException Nh7+Vl  
{ KPIc?|o/6  
oSavedFile = new RandomAccessFile(sName,"rw"); !fXwX3B  
this.nPos = nPos; 8_6\>hW&  
oSavedFile.seek(nPos); ]42bd  
} YoV^Y&:9<  
&o>ctf.x  
o;+$AU1f  
public synchronized int write(byte[] b,int nStart,int nLen) &R:$h*Wt|  
{ B:om61Dn  
int n = -1; y#Je%tAe 2  
try{ SR@yG:~  
oSavedFile.write(b,nStart,nLen); n$n)!XL/  
n = nLen; I^*&u,  
} SnsOuC5Ah  
catch(IOException e) G:NI+E"]  
{ pZ?7'+u$L  
e.printStackTrace (); hm"i\JZ3N  
} rnvKfTpZDU  
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return n; ;*K@8GnU  
} M}|<# i7u  
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} ],l w  
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/* BFP (2j  
**SiteInfoBean.java {//;GC*  
*/ V3j1M?>  
package NetFox; X_yAx)Do  
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public class SiteInfoBean { Enu/Nj 2  
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UV}\#86!  
private String sSiteURL; //Site's URL VPG+]>*  
private String sFilePath; //Saved File's Path ZPHiR4fQli  
private String sFileName; //Saved File's Name es}j6A1  
private int nSplitter; //Count of Splited Downloading File \mRRx#-r%  
#-b0U[,.  
gFR9!=,/V%  
public SiteInfoBean() o RT<h  
{//nSplitter的缺省值为5 K?[*9Q'\  
//default value of nSplitter is 5 Q@B--Omfh  
this("","","",5); jiS|ara"  
} FV>j !>Y  
bvY'=   
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~Pq(Ta  
{ P70\ |M0~y  
sSiteURL= sURL; U40adP? a  
sFilePath = sPath; o4I&?d7;"  
sFileName = sName; >05_#{up  
this.nSplitter = nSpiltter; ~Q7)6%  
!vNZ-}  
@]$qJFXx  
} NHKIZx8sR  
5fpBzn$  
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public String getSSiteURL() t Dx!m~[  
{ $6\-8zNk  
return sSiteURL; LwDm(gG  
} N<bNJD}  
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public void setSSiteURL(String value) S}zh0`+d'Z  
{ ="fq.Tt  
sSiteURL = value; P} =eR  
} 4j9  
-oGJPl{r  
2p3ep,  
public String getSFilePath() B{IYVviiP  
{ xi5/Wc6  
return sFilePath; 6n9;t\'Gt  
} }2qmL$  
X ?p_O2#k  
ISo{>@a-  
public void setSFilePath(String value) c-S_{~~  
{ }q0lbwYlb  
sFilePath = value; sDV*k4  
} yxfV|ox  
}T!2IaAB  
2I!STP{!l  
public String getSFileName() )3O0:]<H  
{ C4V#qhj  
return sFileName; C:C9swik"5  
} Zkn$D:
 
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public void setSFileName(String value) " bHeNWZ  
{ bJ8~/
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sFileName = value; ![O@{/  
} z?C;z7eT  
FS.z lk\D=  
**I9Nw!IH  
public int getNSplitter() {4\hxyw  
{ z!09vDB^  
return nSplitter; ~i)O^CKq  
} JM8s]&  
^Pc>/lY$Q%  
s(yVE  
public void setNSplitter(int nCount) Ve<3XRq|8  
{ :sT\-MpQvn  
nSplitter = nCount; .HTX7mA3  
} #UN(R  
} ;d17xu?ks  
j\w>}P
c  
,Mwyk1:xix  
/* ,}&E=5MF\  
**Utility.java U].u) g$  
*/ g*9jPwdG  
package NetFox; X8T7(w<0%f  
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public class Utility { 13s0uyYU<m  
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)2Gp3oD?  
public Utility() A@/DGrZX  
{ 4_,l[BhsQG  
l6.#s3I['  
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} *!De(lhEc  
l'~]8Wo1  
//线程睡眠 cK.T=7T  
public static void sleep(int nSecond) *"E?n>b  
{ !=#2
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try{ C~M~2@Iori  
Thread.sleep(nSecond); ?i4}[q  
} W%]sI n  
catch(Exception e) fTi,S)F'  
{ `~( P  
e.printStackTrace (); YWA:741  
} 3Lwl~h!  
} nbYkr*: "t  
t/cjz/]  
//日志 .rj FhSr$  
public static void log(String sMsg) H[%Fo  
{ t"1'B!4  
System.err.println(sMsg); WNTm  
} . FT*K[+ih  
qx5X2@-;:  
^o't&  
public static void log(int sMsg) P9J3Ii!  
{ v>Il#  
System.err.println(sMsg); Y_`D5c:  
}  l;>#O  
} [~)i<V|qJ  
5=Bj?xb$'  
ww"ihUX  
/* 96F:%|yG  
**TestMethod.java ~4Is   
*/ z]>aWH}$  
package NetFox; |0w'+HaE~N  
G?QFF6)}!  
?G
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public class TestMethod { ( DwIAO/S  
Sm#;fx+  
a<Pi J?  
public TestMethod() sTqy-^e7  
{ ///xx/weblogic60b2_win.exe e#k9}n^+  
try{ %dZD;Vhg  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6__@?XzJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #ITx[X89|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >c7/E  
fileFetch.start(); ,$3  
} \E.t=XBn  
catch(Exception e){e.printStackTrace ();} L&ws[8-  
]^gD@]
.  
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} QN-n9f8  
6f=/vRAh$  
5S7`gN.  
public static void main(String[] args) ,@!8jar@w}  
{ nx=#QLi  
new TestMethod(); *D<S \6=  
} $E|W|4N
 
} |dD!@K  
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