http断点续传简单实现（java)

/* J3e96t~u  
**SiteFileFetch.java 5]NqRI^0  
*/ Kf>A\l^X7  
package NetFox; C>-aIz!y  
import java.io.*; O[I\A[*  
import java.net.*; R9'b-5q  
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public class SiteFileFetch extends Thread { V}J)\VZ2#  
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SiteInfoBean siteInfoBean = null; //文件信息Bean U}6B*Xx'  
long[] nStartPos; //开始位置 6ys &zy  
long[] nEndPos; //结束位置 4A8;tU$&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 G'oG</A  
long nFileLength; //文件长度 S0B|#O%Z  
boolean bFirst = true; //是否第一次取文件 %
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boolean bStop = false; //停止标志 Q9~*<I> h;  
File tmpFile; //文件下载的临时信息 =:&ly'QB&  
DataOutputStream output; //输出到文件的输出流 GNgKo]u  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4.Q} 1%ZN  
public SiteFileFetch(SiteInfoBean bean) throws IOException ABQa 3{v  
{ OjFLPGRCh  
siteInfoBean = bean; =8t]\Y?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &:/hrighH  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); TV<'8L  
if(tmpFile.exists ()) R%{a1r>9h  
{ 9Xj7~,  
bFirst = false; 19HM])Zw\  
read_nPos(); f({Ei`|  
} [NaN>BZ?  
else !qv ea,vw  
{ (MR_^t  
nStartPos = new long[bean.getNSplitter()]; zfc'=ODX  
nEndPos = new long[bean.getNSplitter()]; SW*"\X;  
} : ]sUpO  
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} 4?ICy/,U-  
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public void run() /JHc!D  
{ J&M o%"[)  
//获得文件长度 e8pG"`wM8  
//分割文件 F ~^Jmp7Y  
//实例FileSplitterFetch `V`lo,"\  
//启动FileSplitterFetch线程 luo  
//等待子线程返回 '^No)n\`  
try{ O_ChxX0KP  
if(bFirst) 8vMG5
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{ -*$HddD  
nFileLength = getFileSize(); L\@I*QP  
if(nFileLength == -1) G_0(
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{ n;@bLJ$W  
System.err.println("File Length is not known!"); fDT%!  
} z2g3FUTX)b  
else if(nFileLength == -2) VKq=7^W  
{ yKa{08X:  
System.err.println("File is not access!"); 4Uphfzv3D  
} o=50>$5jlS  
else #:[t^}  
{ F({HP)9b  
for(int i=0;i<nStartPos.length;i++) ]^lw*724'>  
{ $oj:e?
8N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PmKeF}  
} Bwa'`+bC  
for(int i=0;i<nEndPos.length-1;i++) KVn []@#  
{ i+p^ ^t\  
nEndPos = nStartPos[i+1]; )TVFtI=,NN  
} mS~o?q-n  
nEndPos[nEndPos.length-1] = nFileLength; tnPv70m  
} j6Yy6X]  
}
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//启动子线程 ;$smH=I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d8[J@M53|T  
for(int i=0;i<nStartPos.length;i++) L1cI`9  
{ \P.I)n`8 y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X~lVVBO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :-/M?
,Q"  
nStartPos,nEndPos,i); 6LalW5I  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BI3@|,._N  
fileSplitterFetch.start(); Lv|q  
} n?- })  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {so`/EWa  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); CIb2J)qev  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -
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nEndPos = " + nFileLength); 8=NM|i  
// fileSplitterFetch[nPos.length-1].start(); gj*+\3KO@a  
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//等待子线程结束 5]AC*2(  
//int count = 0; f33l$pOp  
//是否结束while循环 - `p4-J!Fy  
boolean breakWhile = false; ] Hztb  
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5  
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while(!bStop) G/7cK\^u  
{ ?d{Na=O\  
write_nPos(); xx#zN0I>-y  
Utility.sleep(500); `< xn8h9p  
breakWhile = true; "|qqUKJZ  
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for(int i=0;i<nStartPos.length;i++) j2QmxTa!  
{ /SrCElabP  
if(!fileSplitterFetch.bDownOver) 45,1-? -!  
{ ?u" 4@  
breakWhile = false; mF,Y?ax  
break; K`u(/kz/<  
} `HZ;NRr  
} |}(`kW  
if(breakWhile) FaDjLo2'o  
break; |wH5sjT
 
,*7 (%k^`  
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//count++; (Iaf?J5{  
//if(count>4) `
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// siteStop(); @d 
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} Exc9` 7%.  
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System.err.println("文件下载结束！"); l'/R&`-n  
} ;/r1}tl+3>  
catch(Exception e){e.printStackTrace ();} 19E8'@
  
} tt0f-:#  
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//获得文件长度 A8uVK5  
public long getFileSize() +@p% p  
{ mLP.t%?#  
int nFileLength = -1; y5*Z3"<  
try{ 7"20hAd  
URL url = new URL(siteInfoBean.getSSiteURL()); -* WXMzr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DAcQz4T`  
httpConnection.setRequestProperty("User-Agent","NetFox"); =kJ,%\E`  
:h\Q;?  
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int responseCode=httpConnection.getResponseCode(); n%-R[vW  
if(responseCode>=400) `(_s|-$  
{ KH(%?  
processErrorCode(responseCode); mlJ!:WG  
return -2; //-2 represent access is error 5|o6v1bM  
} ca7=V/i_a{  
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String sHeader; mS(fgq6  
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for(int i=1;;i++) S- pV_Ff  
{ 9Uj$K>:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &PYK8}pBk3  
//Utility.log(in.readLine()); NG "C&v  
sHeader=httpConnection.getHeaderFieldKey(i); D~
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if(sHeader!=null) 6kpg+{;  
{ *AO,
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if(sHeader.equals("Content-Length")) 'EbWFMjy  
{ jQ2Ot<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u%}nw :>  
break; e1%/26\  
} 5*lT.  
} >O*IQ[r-  
else CE#gfP  
break; F`gi_;c  
} VH9dleZ  
} /{+y2.{j  
catch(IOException e){e.printStackTrace ();} D8Ykg >B;&  
catch(Exception e){e.printStackTrace ();} 95 ;x=ju  
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Utility.log(nFileLength); DI:]GED"=  
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return nFileLength; NidIVbT.A  
} B8f8w)m  
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//保存下载信息（文件指针位置） "e.jZcN*  
private void write_nPos() 7 n8"/0kc:  
{ DJ'zz&K  
try{ coW:DFX  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &;^YBW:I  
output.writeInt(nStartPos.length); z\K"Rg~J  
for(int i=0;i<nStartPos.length;i++) yE:+Lo`>  
{
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// output.writeLong(nPos); lR )
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output.writeLong(fileSplitterFetch.nStartPos);  .E`\MtA  
output.writeLong(fileSplitterFetch.nEndPos); X:HacYqtC  
} T ]t'39  
output.close(); ZA0mz 65  
} hIy~B['  
catch(IOException e){e.printStackTrace ();} B"h#C!E  
catch(Exception e){e.printStackTrace ();} @ [:ZS+1  
}
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//读取保存的下载信息（文件指针位置） CyS$|E  
private void read_nPos() &]`(v}`]  
{ T|nDTezr  
try{ z@!`:'ak  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]A~WIF  
int nCount = input.readInt(); [<n2Uz7MP  
nStartPos = new long[nCount]; (}Z@R#njH  
nEndPos = new long[nCount]; */sS`/Lx  
for(int i=0;i<nStartPos.length;i++) ojcA<60 '  
{ U#lCj0iUt,  
nStartPos = input.readLong(); A P)L:7w'e  
nEndPos = input.readLong(); eD,.~Y#?=  
}  _zY#U9  
input.close(); FHj" nB  
} ur)9x^y  
catch(IOException e){e.printStackTrace ();} Of*Pw[vD  
catch(Exception e){e.printStackTrace ();} 4ezEW|S  
} _ TiuY  
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private void processErrorCode(int nErrorCode) aS{|uE]  
{ =bfJ^]R  
System.err.println("Error Code : " + nErrorCode); 7%5z p|3  
} @$ne{2J3  
$ `ov4W  
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//停止文件下载 pmuvg6@h  
public void siteStop() ~ksi</s  
{ 6n,i0W  
bStop = true; |:nn>E}ZA/  
for(int i=0;i<nStartPos.length;i++) ff]6aR/ UQ  
fileSplitterFetch.splitterStop(); Vr]id  
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} MI/MhkS ?  
} 94h]~GqNi  
//负责部分文件的抓取 <^&ehy:7y  
**FileSplitterFetch.java ?9!6%]2D  
*/ ,)0H3t  
package NetFox; Bo)3!wO8  
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import java.io.*; (/=f6^}  
import java.net.*; EAT"pxP  
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public class FileSplitterFetch extends Thread { joFm]3$;  
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String sURL; //File URL 1Ir21un  
long nStartPos; //File Snippet Start Position k Z?=AXu  
long nEndPos; //File Snippet End Position F^WP<0C  
int nThreadID; //Thread's ID F0GxH?  
boolean bDownOver = false; //Downing is over (l\1n;s*B  
boolean bStop = false; //Stop identical !\-{D$E?H  
FileAccessI fileAccessI = null; //File Access interface {x|[p_?  
8m-U){r!U^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *w
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{ SEo'(-5  
this.sURL = sURL; tI`Q/a5@  
this.nStartPos = nStart; $mu^G t  
this.nEndPos = nEnd; *1uKr9  
nThreadID = id; o*-)Tq8GHE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 vmU@^2JSJ  
} Z?6%;n^ 54  
@3) (BpFe  
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public void run() J1,9kCO  
{ p, h9D_  
while(nStartPos < nEndPos && !bStop) E%yNa]\P  
{ o*b] p-  
2y//
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try{ +NeOSQSj  
URL url = new URL(sURL); \.0^n3y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); q8FTi^=Kb  
String sProperty = "bytes="+nStartPos+"-"; ? E1<!~  
httpConnection.setRequestProperty("RANGE",sProperty); 7S-ys+  
Utility.log(sProperty); MDnKX?Y  
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6^V=?~a&z  
InputStream input = httpConnection.getInputStream(); pM+ AjPr  
//logResponseHead(httpConnection); 2a-w% (K  
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byte[] b = new byte[1024]; B\=L3eL<D  
int nRead; UxbjA- U[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6@Y_*4$|  
{ sQ=]NF)\  
nStartPos += fileAccessI.write(b,0,nRead); hB"fhX  
//if(nThreadID == 1) tWJZoD6}h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P60~V"/P  
} 2V"B:X\  
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Utility.log("Thread " + nThreadID + " is over!"); 61Bwb]\f/|  
bDownOver = true; }d[ kxo  
//nPos = fileAccessI.write (b,0,nRead); bbtGXfI+SB  
} dV*]f$wQ  
catch(Exception e){e.printStackTrace ();} ZEXc%-M  
} sz5MH!/PJ  
} fWCo;4<5?  

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//打印回应的头信息 FGPB:  
public void logResponseHead(HttpURLConnection con) m-%E-nr  
{ N/[p <  
for(int i=1;;i++) '@cANGg7[  
{ kj|6iG  
String header=con.getHeaderFieldKey(i); 8|b3j^u  
if(header!=null) 2;
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); Kc!}`Pm  
Utility.log(header+" : "+con.getHeaderField(header)); 4ae`pAu  
else ?# Mr  
break; 8/DS:uM  
} ucuSe!IcX  
} :lX!\(E2  
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public void splitterStop() v&Ii^?CvO  
{ wJg1Y0nh  
bStop = true; R]Vt Y7}i,  
} G !<Z.]  
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} 214Ml0/%  
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/* }xKP~h'F  
**FileAccess.java ,368d9,rDz  
*//文件访问(定位，写) PvR6 z0  
package NetFox; <z+t,<3D  
import java.io.*; 7.-V-?i  
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 ^le<}  
public class FileAccessI implements Serializable{ [M?}uK ^  
zqd@EF6/bz  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LU+3{O5y  
RandomAccessFile oSavedFile; t^VwR=i  
long nPos; Bm.afsM;  
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public FileAccessI() throws IOException sJ\BF  
{ TvwZW!@jc  
this("",0); Z<U6<{b  
} `+`Z7  
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public FileAccessI(String sName,long nPos) throws IOException @<<<C?CTv  
{ K*\'.~[6  
oSavedFile = new RandomAccessFile(sName,"rw"); UT>s5C  
this.nPos = nPos; r)qnl9?;`]  
oSavedFile.seek(nPos); "vA}FV%tRq  
} jnd[6v=C7-  
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public synchronized int write(byte[] b,int nStart,int nLen) 85lCj-cs  
{ |b[+I?X  
int n = -1; L9-h;] x!  
try{ =5aDM\L$&  
oSavedFile.write(b,nStart,nLen); soPLA68  
n = nLen; ]&?Y~"{cD  
} DvME1]7)  
catch(IOException e) ~0?mBy!-O  
{ Xsa2(-  
e.printStackTrace (); & SiP\65N  
} 4f@o m
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return n; )_a~} U]=.  
} b`L%t:u{d  
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} Z.d7U~_  
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/* f @8mS   
**SiteInfoBean.java pa#d L!J  
*/ 5>VY LI  
package NetFox; dG@"!!,  
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public class SiteInfoBean { *+'x~a  
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private String sSiteURL; //Site's URL 1[kMOp  
private String sFilePath; //Saved File's Path 6cpw~  
private String sFileName; //Saved File's Name ^?$W
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private int nSplitter; //Count of Splited Downloading File 0- ><q  
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public SiteInfoBean() 5'0xz.)!  
{//nSplitter的缺省值为5 b k|m4|  
//default value of nSplitter is 5 |M8WyW  
this("","","",5);
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} %cCs?ic  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~UyV<  
{ ktK_e  
sSiteURL= sURL; ~CtL9m3tO  
sFilePath = sPath; <$6QDfa#  
sFileName = sName; PpV'F[|,r  
this.nSplitter = nSpiltter; tS|9fBdCs  
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} .udv"?!z  
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public String getSSiteURL() ,B08i o-  
{ Z?pnj8h-&  
return sSiteURL; _tSAI  
} 76>7=#m0u'  
[v$0[IuY,  
#BJG9DFP4`  
public void setSSiteURL(String value) cHcmgW\4  
{ T_X6Ulp  
sSiteURL = value; mK[)mC _8  
} Qhs/E`k4  
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public String getSFilePath() 76V 6cI=+  
{ HODz*pI  
return sFilePath; o[v\|Q`d  
} *4U^0e  
J
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IGS1|  
public void setSFilePath(String value) rm4.aO~-F  
{ vy_D>tp  
sFilePath = value; '7D,m H  
} ?notxE7 ]  
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public String getSFileName() W3Dc r@Dy  
{ v$(lZa1  
return sFileName; 61/.K_%I.  
} LVc4CE f  
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public void setSFileName(String value) CqHK%M  
{ Rp*R:3 C  
sFileName = value; ~zil/P8  
} RletL)  
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'; =f  
public int getNSplitter() &ZghMq~  
{ `6 /$M!4$  
return nSplitter; XO-Prs  
} u$*56y  
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public void setNSplitter(int nCount) 6'kS_Zu{<  
{ K`/`|1  
nSplitter = nCount; $&$w Y/F  
} |}{B1A  
} Ubh{!Y  
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/* GuGOePV  
**Utility.java #VB')^d<U  
*/ AK= h[2(  
package NetFox; >$
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>*-FV{{  
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public class Utility { <&&SX;  
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public Utility() |,#t^'S!  
{ MZTx:EN!  
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} VtzI9CD  
;<$H)`*  
//线程睡眠 !/^-;o7  
public static void sleep(int nSecond) Sr&515  
{ -6tgsfEr  
try{ a-"k/P#  
Thread.sleep(nSecond); "V>R9dO{"!  
} Cw~RJ^a_  
catch(Exception e) cTXri8K_  
{ `((Y
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e.printStackTrace (); G0`
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} #l4)HV  
} Kx.X
7R  
f'<Q.Vh<  
//日志 Mmo6MZ^  
public static void log(String sMsg) Q\GDrdA  
{ K,6b3kk  
System.err.println(sMsg); N0K){  
} wO:Sg=,  
 U3izvM  
I=7Y]w=  
public static void log(int sMsg) S@}1t4Ls:  
{ "]m+z)lWd  
System.err.println(sMsg); Vo9F  
} dWXstb:[  
} cXR1grz  
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I.Y['%8,5~  
/* {ekCQeDo  
**TestMethod.java nI/kw%<  
*/ 3#vinz  
package NetFox; Fi.aC;sx  
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&X|<@'933  
public class TestMethod { {TO
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public TestMethod() ]l@ qra  
{ ///xx/weblogic60b2_win.exe q;fKcblKj  
try{ l"{Sm6:;-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X*g(q0N<S  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >Jw6l0z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); qC_mu)6  
fileFetch.start(); 8 F2|  
} xy8#2  
catch(Exception e){e.printStackTrace ();} ~ ^>417>  
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} 9D 0dg(  
k-E{d04-2  
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public static void main(String[] args) 4D$;KokZ  
{ g|Y] wd  
new TestMethod(); O<jPGU  
} F( Ak  
} 9'DtaTmGW  
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