http断点续传简单实现（java)

/* Px?0)^"2  
**SiteFileFetch.java \$2zF8  
*/ . "`f~s\G  
package NetFox; 3y-P-NI~=  
import java.io.*; }62Q{>`  
import java.net.*; $"`e^J9!!  
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public class SiteFileFetch extends Thread { P;p;o]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 5z"[{#/  
long[] nStartPos; //开始位置 @gihIysf  
long[] nEndPos; //结束位置 (:|1h@K/R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "oT]_WHqo  
long nFileLength; //文件长度 lsB.>NlU  
boolean bFirst = true; //是否第一次取文件 k:CSH{s5{  
boolean bStop = false; //停止标志 *|)O  
File tmpFile; //文件下载的临时信息 kI/%|L%6D  
DataOutputStream output; //输出到文件的输出流 FO?I}G22  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ph@2[rUp  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5z9'~Gfb  
{ txy'7t  
siteInfoBean = bean; _OR[RGy  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 09Y:(2Qri  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $ Bdxu  
if(tmpFile.exists ()) a`S3v  
{ _Uup*#m  
bFirst = false; wI2fCq(a0
 
read_nPos(); 2Q[q)u  
} 3H,>[&d  
else
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{ T%1Kh'92  
nStartPos = new long[bean.getNSplitter()]; 5 OF*PBZ  
nEndPos = new long[bean.getNSplitter()]; q??N,  
} B \>W  
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} 6G>bZ+  
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public void run() 8'Q1'yc  
{ 1xMD )V:  
//获得文件长度 LQ4F/[1}  
//分割文件 j'&a)-Wx_  
//实例FileSplitterFetch bv'Z~@<c  
//启动FileSplitterFetch线程 sys;Rz2  
//等待子线程返回 60%EmX ;  
try{ /n#t.XJY*  
if(bFirst) K]dX5vJw'  
{ c
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nFileLength = getFileSize();  `/eh  
if(nFileLength == -1)
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{ pqxBu  
System.err.println("File Length is not known!"); Kw,l
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} }#9 |au`  
else if(nFileLength == -2) `pYL/[5  
{ 3Tr}t.mt  
System.err.println("File is not access!"); ,:"c"  
} KPs @v@5M  
else )\,hc$<=m  
{ d,%@*v]S  
for(int i=0;i<nStartPos.length;i++) KS(Ms*k;'  
{ u^&,~n@n7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4L[-[{2  
} v@ OM  
for(int i=0;i<nEndPos.length-1;i++) _c6 zzGtH  
{ Lcy>!3q3~  
nEndPos = nStartPos[i+1]; `jH0FJQ  
} ?&r>`H E  
nEndPos[nEndPos.length-1] = nFileLength; vA,tW,  
} ED R*1!d  
} d)jX%Z$LC  
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//启动子线程 C$fQ[@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; qAR}D~t  
for(int i=0;i<nStartPos.length;i++) J`{HMv  
{ /A/k13 J  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q OP8{~O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Se&%Dr3Nv  
nStartPos,nEndPos,i); AC/82$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2[$` ]{U  
fileSplitterFetch.start(); <t4l5nr#  
} Wy,Tf*[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <=7^D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vxx7aPjC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'C|yUsBC  
nEndPos = " + nFileLength); a+{95"4  
// fileSplitterFetch[nPos.length-1].start(); K>fY9`Whm  
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//等待子线程结束 IDr$Vu4LCW  
//int count = 0; [:\8Ug8  
//是否结束while循环 .6#Y-iJqc  
boolean breakWhile = false; Z )dz  
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while(!bStop) EL-1o02-  
{ B%d2tsDw  
write_nPos(); 7U{g'<  
Utility.sleep(500); [!E~pW%|n  
breakWhile = true; ;yK:.Vg  
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for(int i=0;i<nStartPos.length;i++) haMt2S2_B:  
{ za@`,Yq  
if(!fileSplitterFetch.bDownOver) {BKr/) H  
{ H&zhYKw  
breakWhile = false; SvR? nN|  
break; XDi[Iyj  
} ZICcZG_y  
} {,rVA(I@  
if(breakWhile) Nm]\0m0p-  
break; kKg%[zXS  
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//count++; E-q*u(IW  
//if(count>4) z!6:Dt6^  
// siteStop(); p6'wg#15  
} |J#mgA}(  
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System.err.println("文件下载结束！"); sS|N.2*  
} \aG:l.IM0  
catch(Exception e){e.printStackTrace ();} 4l*4wx""v  
} W
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//获得文件长度 &u/T,jy`  
public long getFileSize() zWh[U'6  
{ ]o]*&[C  
int nFileLength = -1; cCH2=v4hU  
try{ X%._:st  
URL url = new URL(siteInfoBean.getSSiteURL()); 9 6'{ES9D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V+kU^mI  
httpConnection.setRequestProperty("User-Agent","NetFox"); "cUCB  
vc_ 5!K%[  
2!35Tj"RFE  
int responseCode=httpConnection.getResponseCode(); $xf{m9 8  
if(responseCode>=400) ,@Izx  
{ L4'FL?~I  
processErrorCode(responseCode); *.DTcV  
return -2; //-2 represent access is error Lh5d2}tcO  
} ;9hi2_luV  
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String sHeader; w&7-:."1i  
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for(int i=1;;i++) Gq/f|43}@O  
{ @ 0RB.-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); zU9G:jH  
//Utility.log(in.readLine()); kG7q4jFwP  
sHeader=httpConnection.getHeaderFieldKey(i); Z)zWfv}  
if(sHeader!=null) ~agzp`!M  
{ ^{T3lQvt  
if(sHeader.equals("Content-Length")) ]'F{uDm[  
{ 5Go&+|cvJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }bVWV0Aeim  
break; -PSI^%TR#  
} w8Mi:;6  
} &ns !\!  
else 89@e &h*  
break; {g>k-.  
} })R8VJ&C/  
} YolO-5  
catch(IOException e){e.printStackTrace ();} -m:i~^ u  
catch(Exception e){e.printStackTrace ();} d4#Q<!r  
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Utility.log(nFileLength); KGclo-,  
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return nFileLength; o[bG(qHZ  
} wr=h=vXU[  
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//保存下载信息（文件指针位置） yVyh'd:Ik  
private void write_nPos() uLsGb=m%b  
{ `A)9   
try{ IwIk;pB O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U3+{!}gn  
output.writeInt(nStartPos.length); ~
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for(int i=0;i<nStartPos.length;i++) $SQ8,Y,  
{ bN$!G9I!,  
// output.writeLong(nPos); BHE((3  
output.writeLong(fileSplitterFetch.nStartPos); $Gs&' yR  
output.writeLong(fileSplitterFetch.nEndPos); 28;D>6c  
} pHFh7-vj  
output.close(); &rX..l  
} )K8k3]y&  
catch(IOException e){e.printStackTrace ();} 5O Ob(  
catch(Exception e){e.printStackTrace ();} 4-4lh TE(  
} \]U@=w  
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//读取保存的下载信息（文件指针位置） j[XA"DZR<  
private void read_nPos() 8z^?PZ/  
{ K2TO,J3 E  
try{ |i"A!rW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); sD$ \!7:b  
int nCount = input.readInt(); )""i"/Mn  
nStartPos = new long[nCount]; OYJy;u3"  
nEndPos = new long[nCount]; {_1^ GIIS  
for(int i=0;i<nStartPos.length;i++) Z1FO.[FV  
{ zi23k=  
nStartPos = input.readLong(); M#JOX/  
nEndPos = input.readLong(); SzR0Mu3uK  
} [IVT0 i  
input.close(); w|x=^  
} H(ht{.sjI  
catch(IOException e){e.printStackTrace ();} )EYsqj  
catch(Exception e){e.printStackTrace ();} %Yg;s'F>#q  
} j=)Cyg3_%  
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private void processErrorCode(int nErrorCode) ;^:9huN  
{ ch<Fi%)  
System.err.println("Error Code : " + nErrorCode); GV1\8OG7  
} QeA)@x.p  
K6kPNi  
kx'ncxN~  
//停止文件下载 &J_|P43  
public void siteStop() YNbs*i&  
{ 
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bStop = true; +vkqig  
for(int i=0;i<nStartPos.length;i++) 5nr}5bum  
fileSplitterFetch.splitterStop(); lnW/T--  
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} !arcQ:T@G  
} YWeEvo(,=  
//负责部分文件的抓取 +~=>72/r  
**FileSplitterFetch.java g*ES[JJH&  
*/ .s|n}{D_i  
package NetFox; Z~8Xp  
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import java.io.*; 9u1)Kr=e  
import java.net.*; )_b#c+  
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public class FileSplitterFetch extends Thread { Hjli)*ev  
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String sURL; //File URL *9%<}z  
long nStartPos; //File Snippet Start Position E=w$r  
long nEndPos; //File Snippet End Position C/e`O|G  
int nThreadID; //Thread's ID ;u,%an<(  
boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical "OF
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FileAccessI fileAccessI = null; //File Access interface 5Ga
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z?[;Japg  
{ H|T:_*5  
this.sURL = sURL; &qFdP'E;$  
this.nStartPos = nStart; kj
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this.nEndPos = nEnd;
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nThreadID = id; *(L4
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 9x&,`95O  
} z7MJxjH  
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public void run() <8!mmOK1  
{ e>1^i;f  
while(nStartPos < nEndPos && !bStop) q#I/N$F  
{ C;wN>HE  
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try{ @fT*fv   
URL url = new URL(sURL); :q;vZ6Xd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Vlce^\s;  
httpConnection.setRequestProperty("User-Agent","NetFox"); (iGk]Rtzt  
String sProperty = "bytes="+nStartPos+"-"; v*QobI  
httpConnection.setRequestProperty("RANGE",sProperty); z]Z>+|  
Utility.log(sProperty); 5wRDH1z@{  
>9F,=63A  
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InputStream input = httpConnection.getInputStream(); 8;p6~&).C~  
//logResponseHead(httpConnection); uwQ{y>SG  
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byte[] b = new byte[1024]; 6YrkS;_HS  
int nRead; .Q?cNSWU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5)V J  
{ )& %X AW{  
nStartPos += fileAccessI.write(b,0,nRead); [f.[C5f%"'  
//if(nThreadID == 1) (p68Qe%OuG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Lh"Je-x<<  
} @= 6}w_  
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Utility.log("Thread " + nThreadID + " is over!"); >t'/(y  
bDownOver = true; ]0xbvJ8oK  
//nPos = fileAccessI.write (b,0,nRead); [xk1}D  
} @8|-
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catch(Exception e){e.printStackTrace ();} 9Z6] ];8E  
} U{h5uezD  
} c%Yvj  
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//打印回应的头信息 C$aiOK-]+  
public void logResponseHead(HttpURLConnection con)  ,L\OhT  
{ %D\TLY  
for(int i=1;;i++) /Y:_qsO1  
{ B y6:
 
String header=con.getHeaderFieldKey(i); 9HRYk13ae  
if(header!=null) J@H9nw+Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D._q'v<  
Utility.log(header+" : "+con.getHeaderField(header)); 8G1Tpn  
else K`j#'`/KC  
break; jbn{5af  
} Ngu+V  
} _I&0HRi  
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public void splitterStop() &y mfA{s  
{ t}qoIxy)  
bStop = true; Io5-[d  
} | 3!a=  
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} aQMET~A:  
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/* Exc`>Y q  
**FileAccess.java vy[*
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*//文件访问(定位，写) ^EjZ.#2l;  
package NetFox; TWQf2  
import java.io.*; `;*Wt9  
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public class FileAccessI implements Serializable{ c|:H/Y2n|  
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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 E6NkuBQ((  
RandomAccessFile oSavedFile; MQD UJ^I$  
long nPos; >VE,/?71@  
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public FileAccessI() throws IOException e8a_)TU?  
{ xFHc+m' m~  
this("",0); -G(z!ed  
} oS/<)>\Gv  
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public FileAccessI(String sName,long nPos) throws IOException l-XiQ#-{  
{ {uL<$;#i  
oSavedFile = new RandomAccessFile(sName,"rw"); :7e2O!zH_  
this.nPos = nPos; ya5;C"  
oSavedFile.seek(nPos); pTST\0?  
} {Rc/Ten  
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public synchronized int write(byte[] b,int nStart,int nLen) z=N'evx~  
{ AVOzx00U  
int n = -1; Ii
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try{ (%oZgvM  
oSavedFile.write(b,nStart,nLen); ,`^B!U3m   
n = nLen; 8,a&i:C  
} 9<.Fw
V>  
catch(IOException e) F6}Pwz[c  
{ DFwkd/3"  
e.printStackTrace (); F8Rd#^9PD  
} c;&m}ImLe.  
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return n; ?>1AT==wI  
} 7;5?2)+=6  
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} ES;7_.q  
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/* Zi|MWaA.f  
**SiteInfoBean.java Zuo7MR  
*/ ^Gq4Y
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package NetFox; I
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Z WL/AC  
public class SiteInfoBean { 6A
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private String sSiteURL; //Site's URL ^e"BY(  
private String sFilePath; //Saved File's Path IU{~{(
p"  
private String sFileName; //Saved File's Name T@U_;v|rf  
private int nSplitter; //Count of Splited Downloading File E=Ah_zKU  
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public SiteInfoBean() E&Pv:h,pV&  
{//nSplitter的缺省值为5 1/jJ;}  
//default value of nSplitter is 5 eZ[CqUJ&  
this("","","",5); ^cZF#%k  
} 9jDV]!N4  
+6B(LPxgP  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^'lx5+-  
{ Dq)V]
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sSiteURL= sURL; UAFl+d!  
sFilePath = sPath; .</d$FM JE  
sFileName = sName; c+f~>AaI  
this.nSplitter = nSpiltter; V()s!w  
<*V%!pwIG  
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} Pz,kSxe=  
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public String getSSiteURL() 94=Wy-  
{ zy(sekX;  
return sSiteURL; k:Da+w_'1  
} "A~\$  
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public void setSSiteURL(String value) .2q7X{4=  
{ j5Vyo>  
sSiteURL = value; :7KcD\fCj  
} \zR@FOl`q  
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public String getSFilePath() O]DZb+O"  
{ Zgkk%3'^'  
return sFilePath; M/x49qO#  
} cgNK67"(  
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public void setSFilePath(String value) hk3}}jc  
{ 3BAls+<p o  
sFilePath = value; T6=,A }t-  
} 6{B$_Usg  

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public String getSFileName() !f2f gX  
{ wS-D"\4/  
return sFileName; W=|sy-N{2  
} *IG} /O.VT  

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public void setSFileName(String value) $bIVD  
{ zlco?Rt  
sFileName = value; =3$JeNK9  
} Qh<_/X?  
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public int getNSplitter() |k1(|)%G  
{ V|e
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return nSplitter; VI: !#  
} }enm#0Ha  
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public void setNSplitter(int nCount) @W[`^jfQ  
{ X31[  
nSplitter = nCount; |=fa`8mG  
} 8fRk8  
} rJH u~/_Dq  
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/* ]&w8"q  
**Utility.java HR]*75}e  
*/ VRQ'sn@  
package NetFox; [0<N[KZ)  
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public class Utility { i}"Eu< P  
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public Utility() %MGbIMpY  
{ >Vc;s!R  

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4  
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} {_T?0L  
VN6h:-&iY  
//线程睡眠 0aj4.H*%  
public static void sleep(int nSecond) gg $/  
{ @'>h P  
try{ ^h #0e:7<  
Thread.sleep(nSecond); 7%DA0.g  
} Q
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catch(Exception e) *gF8"0s  
{ O(q1R#n-}+  
e.printStackTrace (); i E p{  
} uv,&/,;S  
} TK^9!3  
:'p+Ql~c  
//日志 !o+[L  
public static void log(String sMsg) 6/
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{ zr#n^?m  
System.err.println(sMsg); fGGGz$;N  
} U0>Uqk",  
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-=5]B ;  
public static void log(int sMsg) 1?+%*uoPX  
{ #fdQ\)#q>  
System.err.println(sMsg); o^HzE;L}  
} )vWI{Q]r  
} ,xmL[Yk,  
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/* $}_a`~u  
**TestMethod.java vk;]9o j*  
*/ qcpAjjK  
package NetFox; a2Q_K2t  
4FLL*LCNX  
(NB\wJg $  
public class TestMethod { G_OLUuK?C  
mtfEK3?2*  
NABVU0}
 
public TestMethod() nz-( 8{ae  
{ ///xx/weblogic60b2_win.exe @px4[  
try{ wX?<o  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sUl/9VKl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A_nu:K-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jiAKV0lX W  
fileFetch.start(); Ek#?B6s  
} Qmbl_
#  
catch(Exception e){e.printStackTrace ();} 9qe<bds1  
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} aG&ay3[&
 
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public static void main(String[] args) lxSCN6  
{ #\DKU@|h  
new TestMethod(); cow]qe6K  
} "WPFZw:9  
} WBOe
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