http断点续传简单实现（java)

/* 3{OY&   
**SiteFileFetch.java ernZfd{H  
*/ ')ZxWYT O^  
package NetFox; "#Ov!t  
import java.io.*; ]gI>ay"\QA  
import java.net.*; 49. @Uzo  
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public class SiteFileFetch extends Thread { #
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]r++YIg!j  
long[] nStartPos; //开始位置 4JF)w;X}  
long[] nEndPos; //结束位置 mHc
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 e`gOc*  
long nFileLength; //文件长度 |Yq0zc!  
boolean bFirst = true; //是否第一次取文件 fT9z 4[M  
boolean bStop = false; //停止标志 uLFnuK  
File tmpFile; //文件下载的临时信息 rz/^_dV  
DataOutputStream output; //输出到文件的输出流 A0Z<1|6r*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） . !gkJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException LS1r}cl  
{ 5cLq6[uO  
siteInfoBean = bean;  Z
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !J<}=G5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ACQbw)tiv}  
if(tmpFile.exists ()) m?LnO5Vs  
{ `@.  
bFirst = false; 29eg.E  
read_nPos(); 9e^H
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} $r0~&$T&  
else x\HHu]  
{ t\YN\`XD  
nStartPos = new long[bean.getNSplitter()]; d:KUJ Y.  
nEndPos = new long[bean.getNSplitter()]; .1F(-mLd  
} xRum q  
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} % H"A%  
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public void run() ]WZ_~8  
{ YbS$D  
//获得文件长度 r0 %WGMk2  
//分割文件 A4!IbJD,0  
//实例FileSplitterFetch nsO!  
//启动FileSplitterFetch线程 ~3p :jEM.[  
//等待子线程返回 < H1+qN=]`  
try{ GS),rNBur  
if(bFirst) > Y7nq\  
{ G55-{y9Q  
nFileLength = getFileSize(); B_;W!  
if(nFileLength == -1) BI9~%dm  
{ 77y_?di^I  
System.err.println("File Length is not known!"); SCbN(OBN!  
} z=ItKoM*<  
else if(nFileLength == -2) MF+J3)  
{ ~lB im$o  
System.err.println("File is not access!"); j9)WInYc:  
} 9Z! j
 
else a%3V< "f  
{ L`"PaIMz  
for(int i=0;i<nStartPos.length;i++) <PBrW#:'  
{ "zU}]|R  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1<Vc[p&  
} HK~uu5j  
for(int i=0;i<nEndPos.length-1;i++) ^a9v5hu  
{ D$k<<dvv
 
nEndPos = nStartPos[i+1]; >:5^4/fo*  
} Vs>/q
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nEndPos[nEndPos.length-1] = nFileLength; <sXmk{  
} w&6c`az8  
} EBF608nWfW  
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//启动子线程 OC0dAxq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8)(<U/  
for(int i=0;i<nStartPos.length;i++) Xy_ <Yqx}  
{ r >%reS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8<z]rLQw?%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }(}+I}&~  
nStartPos,nEndPos,i); zj G>=2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); We^!(G  
fileSplitterFetch.start(); dV{N,;z  
} M>Yge~3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1$cX`D`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [8Zq 1tU;G  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", RI,Z&kXj2o  
nEndPos = " + nFileLength); V{51wnxT  
// fileSplitterFetch[nPos.length-1].start(); lZpa)1.tiC  
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//等待子线程结束 NzRpI5\.  
//int count = 0; BIx Z4Ft  
//是否结束while循环 PFP/Pe Ng;  
boolean breakWhile = false; )ESF)aKMiz  
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while(!bStop) &?.k-:iN  
{ h/9{E:ML  
write_nPos(); 4JlB\8rc  
Utility.sleep(500); l.tNq$3pS  
breakWhile = true; 6mH0|:CsY  
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] i;xeo,  
for(int i=0;i<nStartPos.length;i++) !E\xn^  
{ ;d"F'd  
if(!fileSplitterFetch.bDownOver) q%HT)^F9oO  
{ &p\fdR4e  
breakWhile = false; /mELnJ^  
break; yFfa/d  
} fX)C8J^=G  
} [K2\e N~g  
if(breakWhile) k0
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break; }Qj
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//count++; 3EGQ$  
//if(count>4) K]mR9$/  
// siteStop(); I`%\ "bF@  
} <|= UrG  
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System.err.println("文件下载结束！"); vRm.#+Td  
} x"kc:F  
catch(Exception e){e.printStackTrace ();} uo`O$k<;  
} Mx,QgYSu  
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//获得文件长度 Y..   
public long getFileSize() ,X Zo0!  
{ ,Lt+*!;m  
int nFileLength = -1; -i``yf?P  
try{ oObm5e*Z  
URL url = new URL(siteInfoBean.getSSiteURL());
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); uus}NZ:*l  
httpConnection.setRequestProperty("User-Agent","NetFox"); E}U[VtaC  
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int responseCode=httpConnection.getResponseCode(); (<?6X9F:N  
if(responseCode>=400) V=";vRS8  
{ ?2ZggV  
processErrorCode(responseCode); 5@3[t`n'  
return -2; //-2 represent access is error 4@6!E^  
} }kg?A o
o  
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String sHeader; 0i}4T:J@`  
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for(int i=1;;i++) J)O1)fR  
{ 3eUTV<!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _D9`L&X}  
//Utility.log(in.readLine()); ^4@~\#$z  
sHeader=httpConnection.getHeaderFieldKey(i); (yk^%  
if(sHeader!=null) 
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{ \VL[,z=q.  
if(sHeader.equals("Content-Length")) i~\fpay  
{ -uZ bVd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +QNFu){G  
break; $~UQKv>  
} AJ-p|[wPz  
} "kC uCc  
else |*079v  
break; [t55Kz*cD  
} 5ru&In&  
} C2GF N1i  
catch(IOException e){e.printStackTrace ();} I8r5u=PH  
catch(Exception e){e.printStackTrace ();} X#9}|rT56  
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1 h(oty2p  
Utility.log(nFileLength); uWw4l"RK`  
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return nFileLength; TK.a6HJG  
} (fON\)l  
[;M31b3  
[u[`!L=  
//保存下载信息（文件指针位置） nenYP0  
private void write_nPos() 2`(-l{3  
{ q1j<p
)(  
try{  /1-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jbQ2G|:Q  
output.writeInt(nStartPos.length); %MyA;{-F6  
for(int i=0;i<nStartPos.length;i++) @MIBW)P<  
{ jRN*W2]V  
// output.writeLong(nPos); 0raVC=[  
output.writeLong(fileSplitterFetch.nStartPos); UkrqHHpy  
output.writeLong(fileSplitterFetch.nEndPos); W69 -,w/  
} l,Un7]*  
output.close(); %FnaS u  
} m%ZJp7C  
catch(IOException e){e.printStackTrace ();} J_tj9+r^  
catch(Exception e){e.printStackTrace ();} D*+uH;ws  
} K @3 yS8F  
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//读取保存的下载信息（文件指针位置） n*-t =DF  
private void read_nPos() T^h;T{H2  
{ bX#IE[Yp}  
try{ M0`nr}g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $3BCA)5:  
int nCount = input.readInt(); R }M'D15  
nStartPos = new long[nCount]; =jvM$  
nEndPos = new long[nCount]; /sY(/ JE  
for(int i=0;i<nStartPos.length;i++) =T5vu~[J/e  
{ UF)rBAv(/  
nStartPos = input.readLong(); Zd@'
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nEndPos = input.readLong(); LO@.aJpp  
} %Kd&A*  
input.close(); ,]@K6  
} q;3,}emg  
catch(IOException e){e.printStackTrace ();} e*_8B2da  
catch(Exception e){e.printStackTrace ();} %+oWW5
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} dsP|j(y  
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private void processErrorCode(int nErrorCode) QjETu  
{ iMRb` \KH  
System.err.println("Error Code : " + nErrorCode); 
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} %]%.{W\j3  
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//停止文件下载 Mw!?2G[|  
public void siteStop() .#R\t 7m%  
{ Z!Sv/5xx  
bStop = true; ]T\K-;i  
for(int i=0;i<nStartPos.length;i++) $2E n^  
fileSplitterFetch.splitterStop(); A+%oE  
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} hGi"=Oud2  
} MfUG@  
//负责部分文件的抓取 xkR--/f  
**FileSplitterFetch.java "-xm+7  
*/ r{qM!(T  
package NetFox; SeAokz>  
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import java.io.*; $Tu%dE(OF  
import java.net.*; w
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public class FileSplitterFetch extends Thread { R`ajll1  
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String sURL; //File URL v :]y#y  
long nStartPos; //File Snippet Start Position 7uJy<O  
long nEndPos; //File Snippet End Position kXS_:f;M  
int nThreadID; //Thread's ID lZCvH1&"  
boolean bDownOver = false; //Downing is over ,p\^n`A32  
boolean bStop = false; //Stop identical 2|F.JG^  
FileAccessI fileAccessI = null; //File Access interface dT8m$}h9  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8'J>@ uW  
{ #(3w6l2  
this.sURL = sURL;
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this.nStartPos = nStart; rb%P30qc4  
this.nEndPos = nEnd; 9)l-5o:D  
nThreadID = id; zR h1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fV*x2g7w  
} Ous[{"-J  
s]`&9{=E  
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public void run() {'Nvs_{6  
{ `Bx3grZ 7&  
while(nStartPos < nEndPos && !bStop) QQPbKok>  
{ !%J;dOcU  
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try{ YIb5jK`  
URL url = new URL(sURL); *%(8z~(\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b!SGQv(^M  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6NJ"ty9Bp  
String sProperty = "bytes="+nStartPos+"-"; |$Dt6{h  
httpConnection.setRequestProperty("RANGE",sProperty); h8>7si  
Utility.log(sProperty); u7G@VZ Ux5  
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InputStream input = httpConnection.getInputStream(); %KNnss}  
//logResponseHead(httpConnection); kHd_q.  
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byte[] b = new byte[1024]; ~R-S$qizAC  
int nRead; Yo@>O98  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1B=vrGq  
{ /,$;xt-J35  
nStartPos += fileAccessI.write(b,0,nRead); gbwKT`N*  
//if(nThreadID == 1) DbJ:KQ!*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .g DWv  
} R'qB-v.  
_
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Utility.log("Thread " + nThreadID + " is over!"); 8#'<SB  
bDownOver = true; hXM8`iFW5  
//nPos = fileAccessI.write (b,0,nRead); -h^FSW($-R  
} Tn2Z{.q$  
catch(Exception e){e.printStackTrace ();} @gENv~m<OI  
} q7mqzMDk  
} & S_gNa  
,kuJWaUC@  
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//打印回应的头信息 VJBVk8P  
public void logResponseHead(HttpURLConnection con) ZT4._|2
 
{ AuHOdiJ  
for(int i=1;;i++) "o#"u[W,  
{ epj]n=/}[  
String header=con.getHeaderFieldKey(i); jVL<7@_*  
if(header!=null) ^"v~hjM#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Gnp,~F"  
Utility.log(header+" : "+con.getHeaderField(header)); GjE/!6b  
else |M#b`g$JO,  
break; K`* 8*k{  
} cy7GiB2'  
} Tk$rwTCl  
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<  
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public void splitterStop() p.TR1BHw  
{ \lCr~D5  
bStop = true; 6#vD>@H  
} yw"FI!M  
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} G%S=K2v  
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/* 9vCn^G%B  
**FileAccess.java {=IK(H  
*//文件访问(定位，写) >`n0{:.1za  
package NetFox; 1c~c_Cc4  
import java.io.*; \2-!%i,  
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public class FileAccessI implements Serializable{ "6^tG[G%  
,& =(DJ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 M|?qSFv:  
RandomAccessFile oSavedFile; (FbqKx'uq  
long nPos; T nA
d!  
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public FileAccessI() throws IOException cZ\#074u/  
{ wX8T;bo&  
this("",0); ~/Aw[>_;  
} Qc\JUm]  
':!w%& \  
6hXL`A&},  
public FileAccessI(String sName,long nPos) throws IOException y`:}~nUdT  
{ T9KzVxHp5  
oSavedFile = new RandomAccessFile(sName,"rw"); '[I_Iu#,  
this.nPos = nPos; 8HX(1nNj}  
oSavedFile.seek(nPos); )+wBS3BC  
} 4LtFv)i  
K6@QZc5.!  
=#^%; 66z  
public synchronized int write(byte[] b,int nStart,int nLen) iOPv %[  
{ '?E^\\"*  
int n = -1; ldrKk'S,B  
try{ P.3j |)NW  
oSavedFile.write(b,nStart,nLen); %*e6@Hm  
n = nLen; \:8~na+(  
} /tc*jXB  
catch(IOException e) dn$1OhN8M  
{ `"
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e.printStackTrace (); Me yQ`%  
} vi4u `  
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return n; @JT9utct  
} 5(1Zj`>'  
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} R3d>|`) +  
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%CfJ.;BDNE  
/* 7]d396%  
**SiteInfoBean.java Yb%H9A  
*/ j*x8K,fN  
package NetFox; b9)%,3-  
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jiYYDGs77  
public class SiteInfoBean { %h g=@7,|  
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private String sSiteURL; //Site's URL a)MjX<y  
private String sFilePath; //Saved File's Path )W:`Q&/G  
private String sFileName; //Saved File's Name YM 0f_G=
 
private int nSplitter; //Count of Splited Downloading File chQt8Ar3  
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public SiteInfoBean() q5 I2dNE  
{//nSplitter的缺省值为5 x|_%R v  
//default value of nSplitter is 5 zPe4WE|  
this("","","",5); R/waWz\D  
} %'kaNpBz  
v$K`C;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'BpK(PlUh  
{ pNcNU[c  
sSiteURL= sURL; |Pz-  
sFilePath = sPath; A5!jrSyv  
sFileName = sName; :J@q Xa  
this.nSplitter = nSpiltter; muQH!Q  
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2"~!Pu^.j  
} <P3r+ 1|R  
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public String getSSiteURL() 9hHQWv7TgK  
{ !.zUY6  
return sSiteURL; ?O8NyCeb7  
}  02Ur'|  
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0L$v7
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public void setSSiteURL(String value) ZO2u[HSO>  
{ *!,+%0  
sSiteURL = value; [y\ZnoB  
} X1]&j2WR  
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public String getSFilePath() Vl{CD>$,  
{ /u<lh. hPW  
return sFilePath; K7FuMB  
} },2-\-1  
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public void setSFilePath(String value) b=9(gZ 9  
{ |VB}Kv  
sFilePath = value; }9R45h}{<  
} nZfTK>)A0  
l$z[Vh^UU<  
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public String getSFileName() 7I/Sfmqy"O  
{ -g]/Ko]2@$  
return sFileName; x +!<_p  
} V2ypmkn8&  
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public void setSFileName(String value) DdJxb{y7  
{ z_*]joL  
sFileName = value; JS
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}
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public int getNSplitter() y%|nE((  
{ t^&:45~Q  
return nSplitter; yv9~  
} n]}+ :  
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n4 KiC!*i0  
public void setNSplitter(int nCount) -WB?hmx  
{ /&$'v:VB  
nSplitter = nCount; )?%FU?2jrn  
} R$K.;  
} 7,!Mmu  
9;&2LT7z  
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/* ;8JJ#ED  
**Utility.java D2[wv+#)  
*/ 'AF2:T\  
package NetFox; #~Lh#@h  
rnIv|q6@  
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public class Utility { kN`[Q$B  
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public Utility() L4zSro:Si  
{ ldM [8  
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} C:h
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//线程睡眠 s^^X.z ,  
public static void sleep(int nSecond) 5w gtc~  
{ Q#}} 1}Ja  
try{ (i|`PA  
Thread.sleep(nSecond); -vGyEd7  
} ;J2U5Y NO  
catch(Exception e) Ve2z= 6(  
{ ,YSQog  
e.printStackTrace (); 3LG}x/l  
} w(J-[t118  
} @!Il!+^3  
teUCK(;23  
//日志 Ar'}#6  
public static void log(String sMsg) BgA\l+  
{ }[!;c+ke  
System.err.println(sMsg); HoT5 5v!o  
} 7WiVor$g-  
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public static void log(int sMsg) 1UJ(._0hR  
{ vPi\ vU{  
System.err.println(sMsg); ( ]AErz+  
} T?) U|  
} ~r]ZD)  
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9'3bzhT$  
/* +DF<o U~  
**TestMethod.java `tVBV:4\  
*/ F@ZG| &  
package NetFox; 69cOdIt^D  
t}cj8DC!  
B
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public class TestMethod { ]gIXG`  
,ZD!Qb  
YM 7P!8Gc  
public TestMethod() U@|{RP  
{ ///xx/weblogic60b2_win.exe 8hQ"rrj+  
try{ #Q^mdv?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Cs^o- g!L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;p BXAl  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r;y&Wa  
fileFetch.start(); h"l{cDk  
} J%aW^+O  
catch(Exception e){e.printStackTrace ();} KFAB  
9=rYzA?)+  
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} ,<R/x
[  
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public static void main(String[] args) oMLpl3pl  
{ G2;Uv/vR  
new TestMethod(); -3wg9uZ&  
} SQvicZAN)`  
} y3 LWh}~E  
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