http断点续传简单实现（java)

/* oZgjQM$YP  
**SiteFileFetch.java O0v}43J[  
*/ Z5n1@a__  
package NetFox; %[TR^Th6
 
import java.io.*; :3Ox~o  
import java.net.*; 
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public class SiteFileFetch extends Thread { \gaw6S>n}  
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SiteInfoBean siteInfoBean = null; //文件信息Bean IEi^kJflU  
long[] nStartPos; //开始位置 @S;'@VC  
long[] nEndPos; //结束位置 (?c"$|^J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vvMT}-!  
long nFileLength; //文件长度 UI0VtR]   
boolean bFirst = true; //是否第一次取文件 f8dB-FlMm  
boolean bStop = false; //停止标志 &p@O_0nF  
File tmpFile; //文件下载的临时信息 6nvz8f3*r]  
DataOutputStream output; //输出到文件的输出流 Yj49
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 03Ycf'W  
public SiteFileFetch(SiteInfoBean bean) throws IOException (L&d!$,Dv  
{ bI1N@
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siteInfoBean = bean; {!L~@r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9Y9GwL]T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :5<UkN)R(  
if(tmpFile.exists ()) rb.N~  
{ $UWZDD  
bFirst = false; 6bC3O4Rw  
read_nPos(); x 9fip-  
}  }my`K  
else S,UDezxg  
{ v!5 `|\  
nStartPos = new long[bean.getNSplitter()]; a1lh-2xX  
nEndPos = new long[bean.getNSplitter()]; T8$y[W-c  
} A;M'LM-M  
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} Y$_B1_  
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public void run() usF.bkTp  
{ 8l`*]1.W<  
//获得文件长度 #*
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//分割文件 4!?eRY  
//实例FileSplitterFetch wmLs/:~  
//启动FileSplitterFetch线程 VI86KJu  
//等待子线程返回 ^ Ze=uP  
try{ 4tBYR9|  
if(bFirst) H.MI5O(Q  
{ "chDg(jMZ  
nFileLength = getFileSize(); Wne@<+mX  
if(nFileLength == -1) ^1.By^ $  
{ S,he6zS  
System.err.println("File Length is not known!"); t{{QE:/  
} b\2 ds,  
else if(nFileLength == -2) %'pgGC"|  
{ I!K6o.|1  
System.err.println("File is not access!"); 3!]rmZ-W  
} xA*<0O\V  
else > ~O.@|  
{ tWcHb #  
for(int i=0;i<nStartPos.length;i++) VOLj>w  
{ gPPkT"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); WNtW|IV  
} ww1[rCh\+  
for(int i=0;i<nEndPos.length-1;i++) ]/L0,^RI  
{ <e6#lF
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nEndPos = nStartPos[i+1]; OneY_<*a<  
} D&y7-/  
nEndPos[nEndPos.length-1] = nFileLength; K
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} vFm
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} 3bI9Zt#J%&  
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//启动子线程 "w<#^d_6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; kAUymds;O  
for(int i=0;i<nStartPos.length;i++) ef4 i:.  
{ ~P-mC@C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CrTw@AW9)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p!%pP}I  
nStartPos,nEndPos,i); G3T]`Atf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |[8Th4*n  
fileSplitterFetch.start(); 9\(| D#  
} Q3?F(ER@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p]c%f2E>d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;O,jUiQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", qHsA1<wg  
nEndPos = " + nFileLength); N;%6:I./  
// fileSplitterFetch[nPos.length-1].start(); f$QNg0v  
v3>UV8c'  
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//等待子线程结束 y@yD5$/  
//int count = 0; 8&dF  
//是否结束while循环 <#4h}_xA%  
boolean breakWhile = false; E]r?{t`]  
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while(!bStop) YS_;OFsd  
{ 1$ {SRU7l  
write_nPos(); Vxt+]5X  
Utility.sleep(500); BZ^}J!Q'*  
breakWhile = true; oXgcc*j  
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for(int i=0;i<nStartPos.length;i++) N'=gep0
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{ [Ch.cE_  
if(!fileSplitterFetch.bDownOver) 7G],T++N  
{ klhtKp_p  
breakWhile = false; 2Tppcj v  
break; [2cD:JL  
} FpU>^'2]  
} d#wVLmKZ  
if(breakWhile) q@2siI~W  
break; pfI&E#:5  
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//count++; e+K^Aq  
//if(count>4) BJ(M2|VH  
// siteStop(); 08{@rOr  
} Etm?'  
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System.err.println("文件下载结束！"); =Fl^`*n  
} T51 `oZ`  
catch(Exception e){e.printStackTrace ();} > Nr#O  
} _SkLYL!=9  
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//获得文件长度 ov
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public long getFileSize() RG`1en  
{ =g
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int nFileLength = -1; =tY T8Q;al  
try{ |Q>IrT  
URL url = new URL(siteInfoBean.getSSiteURL()); IE~ |iQ?-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); #_lDss  
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T
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int responseCode=httpConnection.getResponseCode(); u#SWj,X  
if(responseCode>=400) k VQ\1!  
{ Aiea\jBv  
processErrorCode(responseCode); vfo~27T{(  
return -2; //-2 represent access is error rVsJ`+L  
} Af{"pzY  
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String sHeader; p
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for(int i=1;;i++) u<&m]]*  
{ H>@+om  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); t |oR7qa{w  
//Utility.log(in.readLine()); CJI~_3+K  
sHeader=httpConnection.getHeaderFieldKey(i); W@!S%Y9  
if(sHeader!=null) ,7b[!#?8  
{ OZ!^ak  
if(sHeader.equals("Content-Length")) 4E?Oky#}-  
{ 6LZ;T.0o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); S21,VpW\  
break; t0?\l)  
} POR\e|hRT]  
} VLN_w$iEq  
else e?f IXk~b  
break; #R RRu2  
} >lM l  
} N17RLz *\  
catch(IOException e){e.printStackTrace ();} & ZB  
catch(Exception e){e.printStackTrace ();} 5*D/%]YsD  
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Utility.log(nFileLength); 8-6L|#J#  
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return nFileLength; ws^ np  
} 7J&4akT{9  
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//保存下载信息（文件指针位置） Zj4Uak  
private void write_nPos() GowH]MO  
{ jlg(drTo  
try{ CVR3 A'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5rUdv}.  
output.writeInt(nStartPos.length); .3!1`L3  
for(int i=0;i<nStartPos.length;i++) @ur+;IK$  
{ T9q-,w/j;  
// output.writeLong(nPos); 7j)8Djzp|  
output.writeLong(fileSplitterFetch.nStartPos); W`*r>`krVJ  
output.writeLong(fileSplitterFetch.nEndPos); 7T'B6`-Ox  
} r!{Up7uL  
output.close(); 8e"gW >f  
} G9@0@2aY8  
catch(IOException e){e.printStackTrace ();} *k>n<p3dd  
catch(Exception e){e.printStackTrace ();} Q)z8PQl O  
} BDZ?Ez\Sg  
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//读取保存的下载信息（文件指针位置） $,fX:x  
private void read_nPos() EDs\,f}  
{ _t}WsEQ+P  
try{ 5+ MS^H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $ o#V#  
int nCount = input.readInt(); b\+`e
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nStartPos = new long[nCount]; [;sRV<  
nEndPos = new long[nCount]; HiJE}V;Vq  
for(int i=0;i<nStartPos.length;i++) E q+_&Wk  
{ 7i1q wRv  
nStartPos = input.readLong(); 7 x?<*T  
nEndPos = input.readLong(); @gXx1hEg  
} b*Q&CL  
input.close(); r-/`"j{O!  
} R_S.tT!  
catch(IOException e){e.printStackTrace ();} ]:/Q]n^  
catch(Exception e){e.printStackTrace ();} lCHO;7YHX  
} *siFj CN<  
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private void processErrorCode(int nErrorCode) &XU
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{ tIS<U(N;  
System.err.println("Error Code : " + nErrorCode); >~+ELVB&  
} L\z~uo3:  
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//停止文件下载 wJY'  
public void siteStop() n>U5R_T  
{ 6/dI6C!  
bStop = true; 4]}'Hln*U  
for(int i=0;i<nStartPos.length;i++) H~z`]5CN  
fileSplitterFetch.splitterStop(); 42ivT_H  
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} 8Kk(8a&v  
} DrK{}uM  
//负责部分文件的抓取 y Fq&8 x<X  
**FileSplitterFetch.java ;@E$}*3[>V  
*/ hqkz^!rp  
package NetFox; URbletSBQ  
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import java.io.*; ?=fyc1  
import java.net.*; F`]2O:[  
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public class FileSplitterFetch extends Thread { ZO$%[ftb  
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String sURL; //File URL SGlNKA},A  
long nStartPos; //File Snippet Start Position KL Xq\{X  
long nEndPos; //File Snippet End Position [0D.K}7|  
int nThreadID; //Thread's ID R<N ]B  
boolean bDownOver = false; //Downing is over |*tp16+6  
boolean bStop = false; //Stop identical k~ /Nv=D  
FileAccessI fileAccessI = null; //File Access interface Aj]V`B:65  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Hc(OI|z~  
{ kt$jm)UI~l  
this.sURL = sURL; XACm[NY_  
this.nStartPos = nStart; [Hh9a;.*}h  
this.nEndPos = nEnd; x0:m-C  
nThreadID = id; e'b(gD}
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8 uwq-/$  
} n^6j9FQ7  
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public void run() L8#5*8W6  
{ !f&g-V  
while(nStartPos < nEndPos && !bStop) @/-\k*T  
{ "C0Q(dr/n  
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try{ w}cPs{Vi"  
URL url = new URL(sURL); j]/RC(;?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d)f :)Ew  
httpConnection.setRequestProperty("User-Agent","NetFox"); [RTs[3E^  
String sProperty = "bytes="+nStartPos+"-"; @@%.t|=  
httpConnection.setRequestProperty("RANGE",sProperty); 
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Utility.log(sProperty); 7g}w+p>  
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InputStream input = httpConnection.getInputStream(); c.F6~IHu7  
//logResponseHead(httpConnection); 9o:Lz5
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byte[] b = new byte[1024]; 54li^   
int nRead; +pn N!:q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }s<4{:cv+  
{ ><HE;cVg?  
nStartPos += fileAccessI.write(b,0,nRead); l}sjD[2  
//if(nThreadID == 1) K1!j fp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :@A9](gI  
} _8UDT^?8,  
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Utility.log("Thread " + nThreadID + " is over!"); yFlm[K5YD  
bDownOver = true; 9.B KI/  
//nPos = fileAccessI.write (b,0,nRead); oc0G|  
} A`o8'+`C  
catch(Exception e){e.printStackTrace ();} PGV/ h  
} qE3UO<FA  
} oJ|j#+Ft  
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//打印回应的头信息 ZlzjVU/E  
public void logResponseHead(HttpURLConnection con) ptxbDzOz  
{ JKGe"  
for(int i=1;;i++) Jd^,]  
{ GKc`xIQ  
String header=con.getHeaderFieldKey(i); Qtv&ijFC  
if(header!=null) i5?q,_
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); R>mmoG}MQ[  
Utility.log(header+" : "+con.getHeaderField(header)); s'J:f$flS  
else g:Xhw$x9  
break; :\7X}n
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} <.izVD4/Gg  
} *QQzvhk  
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public void splitterStop() p\aaJ  
{ o;<Xo&  
bStop = true; mg.kr:  
} DG ;_Vg  
/F'sb[  
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} iaE^a^*
 
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/* YRN06*hS  
**FileAccess.java v+#}rUTF  
*//文件访问(定位，写) I5n^,@md  
package NetFox; $jqq `n_  
import java.io.*; UH-*(MfB  
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public class FileAccessI implements Serializable{
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 O%KsD[W;  
RandomAccessFile oSavedFile; (~wqa 3  
long nPos; X1-'COQS%&  
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public FileAccessI() throws IOException };jN\x?&q  
{ (
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this("",0); 5T2
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} ``\i58K{e  
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public FileAccessI(String sName,long nPos) throws IOException *ipFwQ  
{ MUREiL9L|  
oSavedFile = new RandomAccessFile(sName,"rw"); r@t9Ci=}  
this.nPos = nPos; Mh/dpb\Z  
oSavedFile.seek(nPos); ,*hLFaR-  
} pR
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p=GBUII #  
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public synchronized int write(byte[] b,int nStart,int nLen) N&g3t%F  
{ b Y\K  
int n = -1; 5l2 ?  
try{ IIF]/Ek]  
oSavedFile.write(b,nStart,nLen); se>8Z4  
n = nLen; Cdu4U}^H  
} Za3]d+qm  
catch(IOException e) Zrk4*/ VY  
{ kJzoFFWo$  
e.printStackTrace (); 6ZG+ZHUC&  
} QaS7z#/?.  
h WtVWVNL  
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return n; e .2ib?8  
} {kCw+eXn?  
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} ]#l/2V1  
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/* bg&zo;Ck8T  
**SiteInfoBean.java ;/fF,L{c  
*/ sRx63{  
package NetFox; y7 3VFb  
%]DP#~7[|  
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public class SiteInfoBean { V#t%/l  
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private String sSiteURL; //Site's URL f]|ysf  
private String sFilePath; //Saved File's Path YoZFwRQU  
private String sFileName; //Saved File's Name S=<}:#;u0  
private int nSplitter; //Count of Splited Downloading File 1#*a:F&re  
M/ni6%x  
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public SiteInfoBean() v~V5`%  
{//nSplitter的缺省值为5 Vq5k+3W+  
//default value of nSplitter is 5 CBOi`bEf  
this("","","",5); L,`Lggq-  
} ;8*`{F[  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) WD2]&g  
{ pP?MWe Eg  
sSiteURL= sURL; KJ=6n%6  
sFilePath = sPath; ^xHTWg%9  
sFileName = sName; v'qG26
  
this.nSplitter = nSpiltter; Co9QW/'i  
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} E4W -hq~  
2FF4W54I  
XKttZOiGT  
public String getSSiteURL() i;jw\ed  
{ V9(@Y  
return sSiteURL; v:o({Y 1Aq  
} KgOqbSJ  
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public void setSSiteURL(String value) s3O} 6  
{ NufLzg{  
sSiteURL = value; sz {
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} 2H6,'JK@F  
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public String getSFilePath() U.XNv-M  
{ e~@[18  
return sFilePath; 'fF;(?  
} wX[8A/JPD  
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public void setSFilePath(String value) n\5RAIg  
{ r77PQQDT  
sFilePath = value; W$rH"_@m  
} .k9{Yv0  
2 :mn</z  
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public String getSFileName() rN<b?KE  
{ H nUYqhZS  
return sFileName; Eu-RNrYh#  
} s#DaKPC  
L19C<5>  
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public void setSFileName(String value) Jn3An  
{ *l;B\=KR  
sFileName = value; y^Kph# F"  
} 0B&Y]*  
9}uW}yJ  
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public int getNSplitter() ks97k8B  
{ 80&.JP.
 
return nSplitter; TJ'[--  
} +$(2:S*r  
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2
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public void setNSplitter(int nCount) !]fQ+*X0g  
{ d&u]WVU  
nSplitter = nCount; *gF<m9&  
} d/|D<Sb[s  
} Q~Hh
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}gMDXy}  
4e;yG>  
/* wm")[!h)v  
**Utility.java WN5`;
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*/ bi&*9K0  
package NetFox; HXYRH  
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public class Utility { Fxqp-}:  
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public Utility() #8bsxx!s  
{ ofMY,~w  
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} a9Z%JS]  
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//线程睡眠 80Y\|)  
public static void sleep(int nSecond) <~X>[PK<  
{ gE
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try{ @]c(V%x  
Thread.sleep(nSecond); hj$e|arB  
} 8kOKwEX  
catch(Exception e) N0w`!<y:c  
{ HCJ>X;(`f?  
e.printStackTrace (); f%)zg(YlO  
} 0lsXCr_X  
} ;k86"W  
za9)Q=6FD  
//日志 )VK }m9Ae  
public static void log(String sMsg) Za7q$7F7Bc  
{ P^Q[-e{  
System.err.println(sMsg); 6^n0[7  
} k@D0 {z  
I3:[= ,5  
(?kl$~&|  
public static void log(int sMsg) |Uk" {  
{ TLf9>= OVh  
System.err.println(sMsg); x]{E)d"!  
} j0GMT
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} ?$Wn!"EC8  
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[;.`,/  
/* a7/-wk  
**TestMethod.java \WrFqm#  
*/ (ihP`k-.  
package NetFox; <{:  
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public class TestMethod { z6~ H:k1G%  
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public TestMethod() oi&Wo'DX  
{ ///xx/weblogic60b2_win.exe &Q=ZwC7#  
try{ omf Rs  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); cZ+7.oDu  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yag}fQ(XH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); GOB(#vu  
fileFetch.start(); #Hh^3N  
} "SoHt]%#  
catch(Exception e){e.printStackTrace ();} 5ZPzPUa8~  
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} _uu<4c   
cj|*_}
 
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public static void main(String[] args) $7Mtt.d6  
{ >71&]/Rv  
new TestMethod(); &&<9p;E  
} O^I[ (8Y8  
} 5;TuVU.8Q  
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