http断点续传简单实现（java)

/* >.Q0Tx!P  
**SiteFileFetch.java v7@
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*/  b~!om  
package NetFox; ug6r]0]  
import java.io.*; WzG07 2w  
import java.net.*; *4#on>  
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public class SiteFileFetch extends Thread { f-vK}'Z`,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean d5, FM  
long[] nStartPos; //开始位置 7l}~4dm2J  
long[] nEndPos; //结束位置 #v qz{R~nM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 uAb 03Q  
long nFileLength; //文件长度 k E_ky)  
boolean bFirst = true; //是否第一次取文件 ry,}F@P&  
boolean bStop = false; //停止标志 70<K.T<b  
File tmpFile; //文件下载的临时信息 /s-d?  
DataOutputStream output; //输出到文件的输出流 luF#OPC  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G4yUC<TqBP  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5TET<f6R  
{ s1@@o#r  
siteInfoBean = bean; ew"m!F#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ao!=um5D J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -eYL*P
a  
if(tmpFile.exists ()) nE<J`Wo$f  
{ pU[K%@sC  
bFirst = false; c+;S<g0  
read_nPos(); jmPp-}tS7  
} 4H7Oh*P\j  
else IuWX*b`v  
{ LO>8 j:  
nStartPos = new long[bean.getNSplitter()]; !>|`ly$6  
nEndPos = new long[bean.getNSplitter()]; cX"G7Bh  
} iJ*%dio  
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} 8AX3C s_G  
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public void run() #]5)]LF1q  
{ SW-0h4  
//获得文件长度 ;Yu
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//分割文件 QZYM9a>  
//实例FileSplitterFetch DD6'M U4  
//启动FileSplitterFetch线程 A xR\ned  
//等待子线程返回 &u4Ve8#  
try{ i\Q":4  
if(bFirst) PE7t_iSV  
{ 573~-Jvx  
nFileLength = getFileSize(); j~$)c)h"  
if(nFileLength == -1) c8tP+O9  
{ j5A\y^Kv  
System.err.println("File Length is not known!"); "D!Dr1  
} *hl<Y,W(  
else if(nFileLength == -2) =KW|#]RB^  
{ o7QK8#  
System.err.println("File is not access!"); -sD:+Te  
} rX)o3>q^?  
else =~;zVP   
{ *U2Ck<"]  
for(int i=0;i<nStartPos.length;i++) 8\u;Wf  
{ W-!dMa  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6z`8cI+LRw  
} ]d~MEa9Y|  
for(int i=0;i<nEndPos.length-1;i++) X &09  
{ aEZJNWv  
nEndPos = nStartPos[i+1];
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} ~vkud+r  
nEndPos[nEndPos.length-1] = nFileLength; 2"_ 18l.  
} `C ?a  
} Cb<~i  
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//启动子线程 q2D`1nT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;?#i]Bh>S  
for(int i=0;i<nStartPos.length;i++)  6.vNe  
{ r6<ArX$Yl  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DvU~%%(0^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), dfXV1B5  
nStartPos,nEndPos,i); 2voNg
Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z^C!RSQ  
fileSplitterFetch.start(); @D2`*C9  
} )8\Z=uC  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Vc{/o=1u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Wa@6VY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $t%"Tr  
nEndPos = " + nFileLength); *E$H;wKs8  
// fileSplitterFetch[nPos.length-1].start(); @$_rEdwi  
l'P[5'.  
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//等待子线程结束 WJP`0f3  
//int count = 0; r]xdhR5  
//是否结束while循环 HL|0d }  
boolean breakWhile = false;
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while(!bStop) X6n|Xq3k  
{ `z5v}T  
write_nPos(); 
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Utility.sleep(500); vs*_;vx  
breakWhile = true; A/r;;S)%2  
[UUM^!1  
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for(int i=0;i<nStartPos.length;i++) `,<>){c|  
{ !<JG&9ODP  
if(!fileSplitterFetch.bDownOver) ^$3w&$K*  
{ HP1X\h!Ke  
breakWhile = false; h%4~0  
break; =r=^bNO  
} hnlU,p&y3  
} #IcT @(  
if(breakWhile) s#4))yUR6Z  
break;
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//count++; k B$lkl\C  
//if(count>4) WllCcD1  
// siteStop(); Zm?G'06  
} .f[\G*   
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System.err.println("文件下载结束！"); !!\4'Q[  
}
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catch(Exception e){e.printStackTrace ();} 5k_Mj*{6  
} *m2d#f  
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//获得文件长度 #0#V$AA>  
public long getFileSize() .oB'ttF1  
{ y$"~^8"z  
int nFileLength = -1; 4c9-[KKCV  
try{ l93
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URL url = new URL(siteInfoBean.getSSiteURL()); c'm-XL_La  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cJ1{2R  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,(5dQ`hA0  
as\)S?0`.  
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int responseCode=httpConnection.getResponseCode(); X,Q6  
if(responseCode>=400) `RL(N4H  
{ `-E.n'+  
processErrorCode(responseCode); gDjd{+LUo  
return -2; //-2 represent access is error @vDgpb@TM  
} UwzE'#Q-  
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String sHeader; gs)%.k[BqG  
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for(int i=1;;i++) d60Fi#3d  
{ \^^hG5f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4%Z\G@0<'  
//Utility.log(in.readLine()); P,+0   
sHeader=httpConnection.getHeaderFieldKey(i); 3L\s8O  
if(sHeader!=null) O=9VX  
{ (&a3v  
if(sHeader.equals("Content-Length")) \5v=pDd4g  
{ ({}O M=_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); p3'mJ3MA  
break; &'oacV=  
} XJV3oj  
} 2Q;Y@%G  
else HtS1N}@  
break; '44nk(hM69  
} tS*^}e*  
} bsmoLT  
catch(IOException e){e.printStackTrace ();} [ a65VR~J  
catch(Exception e){e.printStackTrace ();} /ltP@*bo  
}rb ]d'|  
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Utility.log(nFileLength); n=Z[w5  
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return nFileLength; zMHf?HQ-Z  
} 8u~\]1(  
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vYTPZ@RL  
//保存下载信息（文件指针位置） PK|`}z9  
private void write_nPos() Z-;uzx  
{ PSrt/y!  
try{ %V" +}Dr  
output = new DataOutputStream(new FileOutputStream(tmpFile)); E.Gh@i  
output.writeInt(nStartPos.length); k%4A::=  
for(int i=0;i<nStartPos.length;i++) l%)=s~6z  
{ yvH#1F`{q  
// output.writeLong(nPos); %<#$:Qb.  
output.writeLong(fileSplitterFetch.nStartPos); sD8xH  
output.writeLong(fileSplitterFetch.nEndPos); sou$qKoG01  
} \?`d=n=  
output.close(); ,BN}H-W\2  
} 9"u@<]  
catch(IOException e){e.printStackTrace ();} C`K9WJOD  
catch(Exception e){e.printStackTrace ();} qjRiTIp9q  
} :4L5@>b-  
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//读取保存的下载信息（文件指针位置） ![MDmt5Ub^  
private void read_nPos() L)//- k9  
{ Y=wP3q  
try{ @_weMz8}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); yK2*~T,6@  
int nCount = input.readInt(); 7{/:,  
nStartPos = new long[nCount]; rF j)5~  
nEndPos = new long[nCount]; '<E8<b
i  
for(int i=0;i<nStartPos.length;i++) Xrzh*sp  
{ RAkFgC~  
nStartPos = input.readLong(); k:uuJ|  
nEndPos = input.readLong(); TB3T:A>2  
} ?jM7C}  
input.close(); <t|9`l_XW  
} 1V9X(uP  
catch(IOException e){e.printStackTrace ();} 2b&
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catch(Exception e){e.printStackTrace ();} F~- S3p  
} e4_aKuA  
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private void processErrorCode(int nErrorCode) XU })3]/  
{ :DF4g=  
System.err.println("Error Code : " + nErrorCode); YKS'#F2  
} $Q7E#  
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//停止文件下载 UDi3dH=  
public void siteStop() zSM7x  
{ m$UT4,Ol  
bStop = true; _"t.1+-K  
for(int i=0;i<nStartPos.length;i++) %TggNU,  
fileSplitterFetch.splitterStop(); R*5;J`TW  
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} KUqS(u   
} )p_LkX(  
//负责部分文件的抓取 Z*Hxrw\!0  
**FileSplitterFetch.java S2GBX1  
*/ ?g*T3S"  
package NetFox; HyYQQ  
*UxB`iA  
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import java.io.*; jN[6JY1  
import java.net.*; 21EUP6}8j  
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public class FileSplitterFetch extends Thread { z00:59M4  
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=FJ9wiL  
String sURL; //File URL >-o:> 5  
long nStartPos; //File Snippet Start Position cz~FWk  
long nEndPos; //File Snippet End Position %v)'`|i  
int nThreadID; //Thread's ID M&T/vByTn_  
boolean bDownOver = false; //Downing is over vo<#sa^,j  
boolean bStop = false; //Stop identical 8BH)jna`Qo  
FileAccessI fileAccessI = null; //File Access interface 1? hd  
qJzK8eW  
v})
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  /lok3J:  
{ Gqc6).tn  
this.sURL = sURL; H+&w7ER  
this.nStartPos = nStart; BRLU&@G`1  
this.nEndPos = nEnd; dw}3B8]  
nThreadID = id; =F-^RnO%\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ln%_8yth  
} 10a*7 L  
@Lv_\^2/}  
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public void run() S_;:iC]B  
{ aJ_Eh(cF  
while(nStartPos < nEndPos && !bStop) M<m64{m1  
{ F+9`G[  
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try{ !VTS $nJ4  
URL url = new URL(sURL); 0J-ux"kfI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WbzL!zLd!  
httpConnection.setRequestProperty("User-Agent","NetFox"); rbS=Ewk  
String sProperty = "bytes="+nStartPos+"-"; !D5`8  
httpConnection.setRequestProperty("RANGE",sProperty); Elk$9 <<  
Utility.log(sProperty); BD
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InputStream input = httpConnection.getInputStream(); Ym2
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//logResponseHead(httpConnection); iDxgAV f*  
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byte[] b = new byte[1024]; s'=]a-l~  
int nRead; .Vjpkt:H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gbZX'D  
{ M8Lj*JN  
nStartPos += fileAccessI.write(b,0,nRead); P[oB'  
//if(nThreadID == 1) CfnCi_=[`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); phSP+/w  
} [B<{3*R_  
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Utility.log("Thread " + nThreadID + " is over!"); ZSb+92g{L$  
bDownOver = true; !_#js  
//nPos = fileAccessI.write (b,0,nRead); ;9sVWJJCw  
} )pH{b]t  
catch(Exception e){e.printStackTrace ();} >n\Q[W  
} TI&J>/z;$  
} e%>E| 9*u  
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//打印回应的头信息 /bk} J:QRg  
public void logResponseHead(HttpURLConnection con) NFPkK?+  
{ HWZ*Htr  
for(int i=1;;i++) {IwYoRaXa  
{ m&8_i`%<  
String header=con.getHeaderFieldKey(i); rvO+=Tk  
if(header!=null) $MGd>3%y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Nh-*Gt?  
Utility.log(header+" : "+con.getHeaderField(header)); *~X\c Z  
else Ms3/P|{"p  
break; ]F#kM211  
} xB[# a*  
} .{>-.&  
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public void splitterStop() x7>sy,c  
{ 5G[^ah<Tg  
bStop = true; %"V,V3kw4  
} %hQ`b$07t  
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} ]7@Dqd-/S  
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/* 7.-|3Wcg  
**FileAccess.java CeemR>\t  
*//文件访问(定位，写) ~8E rl3=5{  
package NetFox; VgL<uxq  
import java.io.*; r]{:{Z  
;kA2"c]m  
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public class FileAccessI implements Serializable{ g5`YUr+3?h  
5#tvc4+)
  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C5FtJquGN)  
RandomAccessFile oSavedFile; c-{]H8$v  
long nPos; ymu#u  
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public FileAccessI() throws IOException Fx2&ji6u  
{ 3f x!\  
this("",0); 6A<aelE*i  
} ~C3-E %h@Z  
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public FileAccessI(String sName,long nPos) throws IOException ]RJ2`xf  
{ =s<QN*zJB0  
oSavedFile = new RandomAccessFile(sName,"rw"); c$TBHK;c  
this.nPos = nPos; -#h \8Xl  
oSavedFile.seek(nPos); eS M!_2  
} ~-x\E#(  
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public synchronized int write(byte[] b,int nStart,int nLen) bK7DGw`1  
{ qm_\#r  
int n = -1;
7P]pk=mo  
try{ 7UfyOOFa  
oSavedFile.write(b,nStart,nLen); v?J2cL  
n = nLen; mJHX  
} ]b)(=-;>  
catch(IOException e) B Xp3u|t  
{ J2-xnUa]7  
e.printStackTrace (); 8vCHH&`  
} ;#*mB`  
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i "xq SLf=  
return n; O`4X[r1LD  
} 6gn|WO=Wf  
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} )yJjJ:re  
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/* snrfHDhUw  
**SiteInfoBean.java 1'iRx,  
*/ SJfsFi?n  
package NetFox; -M:.D3,L  
;1WclQ!(  
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public class SiteInfoBean { UqH7ec  
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q\\J9`Q$J  
private String sSiteURL; //Site's URL *|'k  
private String sFilePath; //Saved File's Path =e63>*M|  
private String sFileName; //Saved File's Name &b%6pVj  
private int nSplitter; //Count of Splited Downloading File yq2Bz7P  
B}p/
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rW6LMkt72  
public SiteInfoBean() Y\lBPp0{\v  
{//nSplitter的缺省值为5 =1D*K%  
//default value of nSplitter is 5 7RO=X%0A  
this("","","",5); a&&EjI  
} '(Pbz   
}k%>%xQ.  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S5;q)qz2J  
{ t]V)3Ww  
sSiteURL= sURL; B$HQFdTli  
sFilePath = sPath; 8`+X6iZOQ  
sFileName = sName; XHW{EVcF  
this.nSplitter = nSpiltter; z-,'W`  
'Mg%G(3  
)K}b,X`($  
} 'lWNU  
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public String getSSiteURL() /g21.*Z  
{ 3.>jagu  
return sSiteURL; zMDR1/|D  
} tW(E\#!|p<  
Z"P{/~HG  
@9^kl$  
public void setSSiteURL(String value) :x_l"y"  
{ <ioX|.7ZX  
sSiteURL = value; &#WTXTr0=  
} y jb.6  
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public String getSFilePath() Bk8U\U
t  
{ *H;&hq  
return sFilePath; SN11J+  
} lcih [M6z  
 /8.;  
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public void setSFilePath(String value) 1 %*X,E  
{ D}:D,s8UP  
sFilePath = value; SN+&'?$WD  
} j,Mp["X&  
7IHWj<  
 -"<eq0  
public String getSFileName() ;e-iiC]PI  
{ <>-UPRwqI  
return sFileName; }(gXlF  
} UF}fmDi  
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8z@A/$T  
public void setSFileName(String value) ,2u]rLxx;  
{ y:1?~R  
sFileName = value; ow+
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} Yd]f}5F  
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cZ5[A
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public int getNSplitter() 2t_E\W7w+  
{ MEg|AhP  
return nSplitter; +1e*>jE  
} g-6!+>w*>e  
2-2'c?%  
-O2QzzE&  
public void setNSplitter(int nCount) yp8 .\.  
{ cLamqZf3  
nSplitter = nCount; MECR0S9  
} 7 0KZXgBy_  
} enZW2o97c  
<{e0i  
(RGl, x:  
/* lnTl"9F  
**Utility.java aFKks .n3  
*/ S7-?&[oeJ  
package NetFox; Dz.U&+*  

^ 3Vjmv  
l46O=?usDX  
public class Utility { V$@@!q  
w W-GBY3  
TLi0*)}  
public Utility() ci,o'`Q  
{ |Y:T3hra61  
In
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} p_tMl%K  
P^+Og_$  
//线程睡眠 *,mbZE=<  
public static void sleep(int nSecond) u{8Wu;  
{ b@nbXm]Z  
try{ S&@~F|  
Thread.sleep(nSecond); 6jom6/F 4  
} B,}%1+*  
catch(Exception e) 0!xD
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{ (gz|6N  
e.printStackTrace (); ~bvx<:8*%  
} vw3%u+Z&  
} D,]m7yFT  
&AA u:  
//日志 fyT!/  
public static void log(String sMsg) 76xgExOU?C  
{ =yk#z84<  
System.err.println(sMsg); tWD*uAb  
} i9w xP i  
7M5HIK6_  
T7&itgEYG/  
public static void log(int sMsg) <4^a(Zh  
{ @ -g^R4e<  
System.err.println(sMsg); :y0'[LV  
} iQ~cG[6  
} DtyT8kr  
n0nkv[  
9NKZE?5P|D  
/* HH8a"Hq)  
**TestMethod.java /TS>I8V!  
*/ bMf+/n  
package NetFox; R~)c(jj5  
 k:R9wo  
RQv`D&u_  
public class TestMethod { ykM(` 1`m  
W>'R<IY4#N  
s|YY i~  
public TestMethod() -x5^>+Y4  
{ ///xx/weblogic60b2_win.exe o"K{^ L~u  
try{ @~/LsYA:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1,BtOzuRo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QZ%_hvY[%>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5h1FvJg  
fileFetch.start(); o{m$b2BW  
} 2i8'*L+j  
catch(Exception e){e.printStackTrace ();} Eo)n( Z9  
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} sLb[ZQ;j  
8%I4jL<  
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public static void main(String[] args) ;w[|IRa  
{ :@19,.L  
new TestMethod(); '0z@Jevd?  
} 8M8=
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} 
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