http断点续传简单实现（java)

/* TA2ETvz^  
**SiteFileFetch.java YOj&1ymBZ  
*/ ~!Nw]lb!  
package NetFox; 2|d^#8)ZC  
import java.io.*; F&m9G >r  
import java.net.*; WSN^iDS
 
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public class SiteFileFetch extends Thread { iyd$_CJz  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1q3"qYH  
long[] nStartPos; //开始位置 D~URY_[A  
long[] nEndPos; //结束位置 ey,f igjd.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 
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long nFileLength; //文件长度 VB#&`]rdo  
boolean bFirst = true; //是否第一次取文件 R! On  
boolean bStop = false; //停止标志 Lo#G.
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File tmpFile; //文件下载的临时信息 c@"FV,L>  
DataOutputStream output; //输出到文件的输出流 4,Oa(b  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :]]x^wony~  
public SiteFileFetch(SiteInfoBean bean) throws IOException )S 4RR2Q>  
{ :z&kbG  
siteInfoBean = bean; ir>h3Zk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); II|;_j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); HLG5SS7  
if(tmpFile.exists ()) \w>Rmf'
|  
{ 1K<}  
bFirst = false; w
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read_nPos(); &Tj7qlP\  
} FQ1B%u|  
else s}OL)rW=}  
{ 9+PAyI#w  
nStartPos = new long[bean.getNSplitter()]; |iX>hJSl  
nEndPos = new long[bean.getNSplitter()]; 0B!(i.w  
}
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} 7aKI=;60.  
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public void run() law
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{ kp*!  
//获得文件长度 JGTsVa2  
//分割文件 SA&(%f1d  
//实例FileSplitterFetch naH(lz|v  
//启动FileSplitterFetch线程 %.r\P@7/Q  
//等待子线程返回 p9u*l  
try{ A%HIfSzQBS  
if(bFirst) $p4e8j[EJ  
{ k'H[aYMA  
nFileLength = getFileSize(); 6kLy!QS  
if(nFileLength == -1) /j}Tv.'d  
{ +Ln^<!P  
System.err.println("File Length is not known!"); GD]epr%V  
} V|kN 1 A  
else if(nFileLength == -2) &]RE 5!  
{ ")\V  
System.err.println("File is not access!"); L6Brs"9B  
} zGyRzxFN  
else C$~ly=@  
{ 1Q!^*D  
for(int i=0;i<nStartPos.length;i++) 2EZ7Vdz2  
{ !#W>x49}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0F%8d@Y2  
} d=%NFCIV  
for(int i=0;i<nEndPos.length-1;i++) `iM%R3&  
{ l&U$LN$*e  
nEndPos = nStartPos[i+1]; 8b~  
} O65`KOPn  
nEndPos[nEndPos.length-1] = nFileLength; UhL1Y NF_  
} saP%T~  
} ~mXzQbe p  

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//启动子线程 gN:F50  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 'uDx$AkY  
for(int i=0;i<nStartPos.length;i++) Y z&!0Hfd  
{ d7[^pN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =<p=?16 x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BO7HJF)a  
nStartPos,nEndPos,i);  c1s&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1.3dy]vG  
fileSplitterFetch.start(); 43B0ynagN  
} /7Pqy2sgE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xatq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lGWz  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U'(zKqC  
nEndPos = " + nFileLength); 9t)Hi qj  
// fileSplitterFetch[nPos.length-1].start(); *8?2+)5"  
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//等待子线程结束 LOcZadr  
//int count = 0; rZ3ji(4HS  
//是否结束while循环 03v&k  
boolean breakWhile = false; pgh(~[  
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while(!bStop) tJ K58m$  
{ lW-h @  
write_nPos(); OzrIiahz/  
Utility.sleep(500); u%z'.#r;a  
breakWhile = true; 76@W:L*J$J  
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for(int i=0;i<nStartPos.length;i++) l`N#~<.  
{ %\sE\]K  
if(!fileSplitterFetch.bDownOver) J QnaXjW2  
{ O{~Xp!QQt  
breakWhile = false; G>0d^bx;E  
break; P4_B.5rrJ  
} hN!;Tny  
} z=U+FHdh/-  
if(breakWhile) W0sL
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break; 6JZ>&HA  
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//count++; 8CUtY9.  
//if(count>4) r[}nrH&8  
// siteStop(); /kK*%TP  
} ZJZSt% r  
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System.err.println("文件下载结束！"); W g7 eY'FE  
} p:y\{k"  
catch(Exception e){e.printStackTrace ();}
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} QR"+fzOL  
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//获得文件长度 cb]X27uww  
public long getFileSize() y@I9>}"y  
{ d%qi~koN_  
int nFileLength = -1; d}:
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try{ o^X3YaS)  
URL url = new URL(siteInfoBean.getSSiteURL()); 7,p.M)t)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^Z9bA(w8  
httpConnection.setRequestProperty("User-Agent","NetFox"); J+IItO4%  
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int responseCode=httpConnection.getResponseCode(); dGOFSH  
if(responseCode>=400) !`?i>k?Q E  
{ i'H]N8,A  
processErrorCode(responseCode); 
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return -2; //-2 represent access is error F}45.CrD  
} Bc }o3oc  
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String sHeader; qCcLd7`$  
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for(int i=1;;i++) vLN KX;9  
{ rD <T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); H%Vf$1/TF  
//Utility.log(in.readLine()); vA_,TS#Bo  
sHeader=httpConnection.getHeaderFieldKey(i); mm+V*L{x  
if(sHeader!=null) ;-~E!_$  
{ ohKoX$|p~  
if(sHeader.equals("Content-Length")) JYw?  
{ _ncBq;j{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); DKfpap}8u  
break; IKP_%R8.  
} uoE+:,P  
} )r{Wj*u  
else &t8,326;  
break; d"?"(Q_8n  
} f?/OV*  
} }FS_"0  
catch(IOException e){e.printStackTrace ();} {f`Y\_r$@  
catch(Exception e){e.printStackTrace ();} S`5bcxI_  
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Utility.log(nFileLength); +ho=0>  
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return nFileLength; Q]TZyk  
}  ;303fS  
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//保存下载信息（文件指针位置） {0F/6GwUC  
private void write_nPos() Q`8-|(ngw  
{ #$S~QS.g  
try{ ^"|q~2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5&p}^hS5  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) 9F3,  
{ NbU4|Oi  
// output.writeLong(nPos); k%~;mu"4}  
output.writeLong(fileSplitterFetch.nStartPos); uVD^X*  
output.writeLong(fileSplitterFetch.nEndPos); SPlt=*C#_  
} HRE?uBkjf  
output.close(); 5TpvJ1G  
} $S<B\\ %  
catch(IOException e){e.printStackTrace ();} HN`qMGW^  
catch(Exception e){e.printStackTrace ();} DTA$,1JuD  
} {jYVA~.|Z  
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//读取保存的下载信息（文件指针位置） jG&HPVr  
private void read_nPos() JL#LCU ?  
{ AlDp+"|  
try{ pJe!~eyHm  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S+.>{0!S"  
int nCount = input.readInt(); ^`lDw  
nStartPos = new long[nCount]; Ig!0A}f  
nEndPos = new long[nCount]; EMe1!)  
for(int i=0;i<nStartPos.length;i++) a_+3, fP  
{ rZ(#t{]=!  
nStartPos = input.readLong(); .zdaY, U  
nEndPos = input.readLong(); 3HuocwWbz  
} *ezMS   
input.close(); ^#e|^]] L  
} [[T6X9  
catch(IOException e){e.printStackTrace ();} UmpHae  
catch(Exception e){e.printStackTrace ();} \41/84BA  
} .9ZK@xM&?  
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private void processErrorCode(int nErrorCode) V0A>+  
{ 
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System.err.println("Error Code : " + nErrorCode); ;k@]"&t  
} HP*{1Q@5  
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//停止文件下载 aKW-(5<JW  
public void siteStop() k*2khh-  
{ cZYvP  
bStop = true; *%jtcno=Y  
for(int i=0;i<nStartPos.length;i++) Xg
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fileSplitterFetch.splitterStop(); "@VYJ7.1  
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} y,rdyt  
} Tz6I
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//负责部分文件的抓取 _oa*E2VN  
**FileSplitterFetch.java _nz_.w0H9  
*/ 99:.j=  
package NetFox; <<cezSm  
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import java.io.*; 'z}9BGR!  
import java.net.*; /0k'w%V{n  
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public class FileSplitterFetch extends Thread { E83$(6z  
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String sURL; //File URL ~eP~c"L  
long nStartPos; //File Snippet Start Position JP"#9f  
long nEndPos; //File Snippet End Position Xsanc@w)^C  
int nThreadID; //Thread's ID HhCFAq"j  
boolean bDownOver = false; //Downing is over KY<
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boolean bStop = false; //Stop identical Q~f]?a`  
FileAccessI fileAccessI = null; //File Access interface @b 17jmq{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $; _{|{Yj  
{ r@i)Sluf  
this.sURL = sURL; zobFUFx  
this.nStartPos = nStart; P}Mu|AEG  
this.nEndPos = nEnd; a(fiW%eFb  
nThreadID = id; Vr& GsT  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >mvE[iXRG?  
} 46 0/eW\  
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public void run() Rq2bj_j  
{ h*<`ct xL  
while(nStartPos < nEndPos && !bStop) .#tA .%  
{ `%Kj+^|DS  
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try{  =v?V  
URL url = new URL(sURL); YwH Fn+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O+'k4  
httpConnection.setRequestProperty("User-Agent","NetFox"); @JdeOL;  
String sProperty = "bytes="+nStartPos+"-"; 3:$@DZT$  
httpConnection.setRequestProperty("RANGE",sProperty); mV"F<G; H  
Utility.log(sProperty); v#g:]T  
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InputStream input = httpConnection.getInputStream(); Y@UW\d*'%I  
//logResponseHead(httpConnection); &09~ D8f'  
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byte[] b = new byte[1024]; gL| 9hvHr[  
int nRead; VFq\{@- %  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "
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{ V1nqEdhk  
nStartPos += fileAccessI.write(b,0,nRead); d5 ]-{+V+  
//if(nThreadID == 1) RJ4=AA|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )2d1@]6#  
} %2'4h(Oq^  
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Utility.log("Thread " + nThreadID + " is over!"); lxD~l#)^ln  
bDownOver = true; _E0yzkS  
//nPos = fileAccessI.write (b,0,nRead); 2C"i2/NH'  
} SMB&sl  
catch(Exception e){e.printStackTrace ();}  0RCp  
} ZV5IZ&V!  
} c*
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//打印回应的头信息 `\ nKPj  
public void logResponseHead(HttpURLConnection con) &432/=QSm0  
{ J7EWaXGbz  
for(int i=1;;i++) O]="ggq&  
{ =NK'xPr  
String header=con.getHeaderFieldKey(i); QDK }e:4q  
if(header!=null) 6PWw^Cd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); P?8$VAkj  
Utility.log(header+" : "+con.getHeaderField(header)); D}ZPgt#   
else !q/Q2N(  
break; BdvpG  
} y{P~!Y
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} #QOb[9(Tu(  
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public void splitterStop() ??hKsjNAm0  
{ I&1.}{G>F  
bStop = true; X`E}2|q'  
} {~\:4  
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} :< ]sJfN  
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/* `'(@"-L:7  
**FileAccess.java 6|6O| <o  
*//文件访问(定位，写) ^h`rA"F\  
package NetFox; cI7aTLC"s  
import java.io.*; }LWrtmc  
:.-KM7tDI1  
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public class FileAccessI implements Serializable{ hJ4 A5m.  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3][   
RandomAccessFile oSavedFile; I[06R
 
long nPos; 2of+KI:
 
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public FileAccessI() throws IOException +).=}.k  
{ >k}Kf1I  
this("",0); g'-hSV/@}@  
} tM:$H6m/(  
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public FileAccessI(String sName,long nPos) throws IOException v,3}YDu  
{ oO;<$wx2t  
oSavedFile = new RandomAccessFile(sName,"rw"); pBu}c<  
this.nPos = nPos; ~dsx|G?p  
oSavedFile.seek(nPos); [H`5mY@  
} -HFyNk]>  
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_Mh..#)`[  
public synchronized int write(byte[] b,int nStart,int nLen) =k!F`H`/%'  
{ 2:[G4  
int n = -1; 8rz,MsFR  
try{ f[OJqk  
oSavedFile.write(b,nStart,nLen); FT gt$I  
n = nLen;  )Z:maz  
} OtT*)8*c  
catch(IOException e) Zc9S[ivq  
{ eQ#"-i  
e.printStackTrace (); LXc;`]  
} _UF'Cf+Y  
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return n; 2m&?t_W  
} 0+rBGk  
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}  t|:XSJ9  
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/* !-B|x0fs  
**SiteInfoBean.java 3-![%u  
*/ 
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package NetFox; o-A
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public class SiteInfoBean { evyA#~o  
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private String sSiteURL; //Site's URL H)+wkR!~  
private String sFilePath; //Saved File's Path [lj^lN8  
private String sFileName; //Saved File's Name \mwxV!!b$  
private int nSplitter; //Count of Splited Downloading File  !h*F58  
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public SiteInfoBean() pA5X<)~   
{//nSplitter的缺省值为5 jpfFJon)w  
//default value of nSplitter is 5 8{-bG8L> 5  
this("","","",5); B o[aiT  
} G4f%=Z  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cvnRd.&  
{ ^0"[l {  
sSiteURL= sURL; OFw93UJ Y  
sFilePath = sPath; s|Zv>Qt  
sFileName = sName; $Mqw)X&q  
this.nSplitter = nSpiltter; >!P !F(  
"Ze<dB#,Y  

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} onUF@3V  
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public String getSSiteURL() }?%5Ae7l,  
{ n{.SNipU  
return sSiteURL; }{)>aJ  
} GEfTs[  
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public void setSSiteURL(String value) 7Dx<Sr!  
{ C5'#0}6i  
sSiteURL = value; ;jT@eBJ  
} JVNp= ikK  
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;kF+V*  
public String getSFilePath() ~YrO>H` B  
{ Hz3KoO &  
return sFilePath; *8xMe  
} Z;GZ?NOlY  
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public void setSFilePath(String value) Ceak8#|4  
{ M!b"c4|<  
sFilePath = value; =(>pv,  
} p3{ 3[fDx  
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public String getSFileName() Z"'tJ3Y.~  
{ LO M-i>  
return sFileName; c{K[bppJ*  
} $<s 3;>t  
8Ir = @  
[cf!%3>53  
public void setSFileName(String value) I>z0)pB  
{ i6D66E  
sFileName = value; 5KDN8pJN  
} "\M^jO  
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public int getNSplitter() InR/g@n+D1  
{ MFm2p?zPm  
return nSplitter; <ULydBom  
} 'z3I*[!  
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public void setNSplitter(int nCount) 6'1m3<G_  
{ XhG3Of-6  
nSplitter = nCount; B1Cu?k);.  
} l|&DI]gw  
} 0P_3%   
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/* O4A{GO^q  
**Utility.java &S+ooj  
*/ Ow4H7sl  
package NetFox; 80;^]l   
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public class Utility { x 2Cp{+}  
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public Utility() 9&}i[x4  
{ DDwm
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} aJ^RY5  
=S:Snk%  
//线程睡眠 R;EdYbiF b  
public static void sleep(int nSecond) Y('?Z]  
{ ,@4~:OY  
try{ p? L*vcU  
Thread.sleep(nSecond); k]9v${Ke  
} .-HwT3  
catch(Exception e) - HiRXB  
{ 8Xjp5  
e.printStackTrace (); 2\J-7o=P  
} o6T'U#7P  
} @J UCXm  
#cy;((zuB  
//日志 NANgV~Y&  
public static void log(String sMsg) k~=_]sLn  
{ sw$$I~21  
System.err.println(sMsg); Ty;P`Uv]r  
} Ne9S90HsB6  
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public static void log(int sMsg) A{Dy3tm=  
{ /@QPJ~%8Ud  
System.err.println(sMsg); @pkQ2OM 2  
}
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} ap|$8G  
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/* * faG0le  
**TestMethod.java >JckN4v  
*/ GW;O35 m  
package NetFox; zqt{oN_  
Sah
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9qvKg`YSh  
public class TestMethod { 2U.'5uA"L  
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public TestMethod() ! n13B  
{ ///xx/weblogic60b2_win.exe xka&,`z  
try{ H=v=)cUe[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $1}Y4>3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7X`]}z4g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !THa?U;  
fileFetch.start(); c%@< h6  
} Ssg1p#0J  
catch(Exception e){e.printStackTrace ();} bAS/cuZs  
[2\jQv\Y  
}^tW's8  
} B3g#)  
8$`$24Wx  
~KP@wD~  
public static void main(String[] args) vef9*u`  
{ {u)>W@Lr  
new TestMethod(); SS*3Qx:[  
} L~|_CRw  
} @<`P-+m  
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