http断点续传简单实现（java)

/* 2d>hi32I
 
**SiteFileFetch.java +HT1ct+dI  
*/ -_C#wtC  
package NetFox; Gq<X4C#|  
import java.io.*; D]G)j  
import java.net.*; ao_4mSB  
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public class SiteFileFetch extends Thread { WI> P-D  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }Ew hj>w  
long[] nStartPos; //开始位置 j^tW Iz  
long[] nEndPos; //结束位置 39wa|:I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Vwk#qgnX  
long nFileLength; //文件长度 L"jY+{oLIJ  
boolean bFirst = true; //是否第一次取文件 B.r4$:+jb2  
boolean bStop = false; //停止标志 Ian[LbCWB  
File tmpFile; //文件下载的临时信息 ~Nf})U  
DataOutputStream output; //输出到文件的输出流 66x?A0P  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ".^VI2T  
public SiteFileFetch(SiteInfoBean bean) throws IOException _A13[Mt3  
{ xL|;VyD  
siteInfoBean = bean; S"Lx%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NA3\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); osARA3\Xt  
if(tmpFile.exists ()) tZ`Ts}\e  
{ xv{O^Ie+S  
bFirst = false; Wq*b~Lw  
read_nPos(); tE6!+c<7  
} sJwyj D$b  
else /sM~Uq?  
{ yz8mP3"c:o  
nStartPos = new long[bean.getNSplitter()]; fXI:Y8T  
nEndPos = new long[bean.getNSplitter()]; DejA4XdW  
} 0Wa}<]:^  
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} H~ZV*[A`  
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public void run() }Sy=My89r  
{ n  -(  
//获得文件长度 Hbv6_H  
//分割文件 qW:HNEiir  
//实例FileSplitterFetch T91moRv  
//启动FileSplitterFetch线程 K\"R&{+=
 
//等待子线程返回 u:0aM}9A  
try{ lL1k.&|5m  
if(bFirst) pym!U@$t  
{ F}Vr:~  
nFileLength = getFileSize(); 2'=T[<nNB  
if(nFileLength == -1) ifN64`AhRX  
{ uqz]J$
 
System.err.println("File Length is not known!"); s0Z uWVip  
} X7k.zlH7T  
else if(nFileLength == -2) @(r/dZc  
{  hI9  
System.err.println("File is not access!"); __mF?m  
} BIuK @$  
else @gY)8xMbA  
{ V#VN%{  
for(int i=0;i<nStartPos.length;i++) UAoh`6vFF8  
{ )K &(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); MSf;ZB  
} ;M"9$M'  
for(int i=0;i<nEndPos.length-1;i++) N F)~W#  
{ h=;{oY<V)?  
nEndPos = nStartPos[i+1]; w$JvB
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} H":oNpfb  
nEndPos[nEndPos.length-1] = nFileLength; 2UGsYQn  
} 4apL4E"r  
} D!7`CH+  
x _c[B4Tw  
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//启动子线程 cnTaJ/o  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vWAL^?HUP  
for(int i=0;i<nStartPos.length;i++) I`NjqyTW  
{ #g6.Glz3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U&O: _>~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N-lkYL-%\j  
nStartPos,nEndPos,i); sr8cYLm5R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j?'GZ d"B  
fileSplitterFetch.start(); .Wjs~0c  
} H;
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "AE5 V'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <[w=TdCPs  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #%DE;  
nEndPos = " + nFileLength); ):iA\A5q[  
// fileSplitterFetch[nPos.length-1].start(); -GxaV #{  
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//等待子线程结束 UX7t`l2R  
//int count = 0; XI^QF;,  
//是否结束while循环 5oAK8I  
boolean breakWhile = false; X&kp;W  
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while(!bStop) ;^Dpl'v%\  
{
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write_nPos(); 
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Utility.sleep(500); R17?eucZ  
breakWhile = true; h$2</J"  
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for(int i=0;i<nStartPos.length;i++) !r<pmr3f@7  
{ &Xf}8^T<V  
if(!fileSplitterFetch.bDownOver) 4<BjC[@~Z{  
{ wb0L.'jyR)  
breakWhile = false; 1
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break; {;2PL^i  
} z4N*b"QF  
} wpN=,&!  
if(breakWhile) q@{Bt{$x  
break; GWfL  
$&=S#_HQS  
L
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//count++; }4,L%$@n  
//if(count>4) ff^=Ruf$  
// siteStop(); mHRiugb!  
} PpzP7  
7<*yS310
 
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System.err.println("文件下载结束！"); ,y#Kv|R  
} o2F)%TDY  
catch(Exception e){e.printStackTrace ();} ?{[ v+t#  
} J\b^)  
u ,KD4{!  
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//获得文件长度 p>huRp^w  
public long getFileSize() h'{ C[d  
{ x<ZJb  
int nFileLength = -1; [1S|dc>.O%  
try{ " )1V]}+m  
URL url = new URL(siteInfoBean.getSSiteURL()); cz8T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~nay"g:  
httpConnection.setRequestProperty("User-Agent","NetFox"); e~=;c  
JJN.ugT}1  
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int responseCode=httpConnection.getResponseCode(); vQ 6^xvk]  
if(responseCode>=400) xA$XT[D  
{ 1ukTA@Rj&  
processErrorCode(responseCode); EFM5,gB.m  
return -2; //-2 represent access is error Iy&!<r7:]0  
} , K~}\CR  
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String sHeader; J| w>a  
\| 8  
Wi)_H$KII  
for(int i=1;;i++) 9dx/hFA  
{ |Y,b?*UF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <eWf<  
//Utility.log(in.readLine()); ZbdZrE$  
sHeader=httpConnection.getHeaderFieldKey(i); X4~y7  
if(sHeader!=null) b0Ps5G\ u  
{ #cI{Fe0h  
if(sHeader.equals("Content-Length")) 3EPv"f^V  
{ ]>5/PD,wWy  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sYI-5D]  
break; vg32y /l]S  
} rC^WPW  
} Po^?QVJ7  
else zBzZxK>$  
break; W')Yg5T  
} VY7[)  
}
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catch(IOException e){e.printStackTrace ();} 0x@6^%^\  
catch(Exception e){e.printStackTrace ();} *Q "wwpl?  
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Utility.log(nFileLength); 4O^xY 6m  
*RJG!t*t  
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return nFileLength; .1Dg s=|  
} )vE~'W  
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;DfY#-  
//保存下载信息（文件指针位置） _@ qjV~%Sy  
private void write_nPos() 286jI7T  
{ pmyXLT  
try{ 2K/4Rf0;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w;4<h8Wn5  
output.writeInt(nStartPos.length); 4V)kx[j  
for(int i=0;i<nStartPos.length;i++) #lL^?|M  
{ UGV+/zxIM  
// output.writeLong(nPos); ;n*.W|Uph  
output.writeLong(fileSplitterFetch.nStartPos); =O5pY9UO  
output.writeLong(fileSplitterFetch.nEndPos); KPKt^C  
}
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output.close(); Kqb#_hm  
} y51e%n$  
catch(IOException e){e.printStackTrace ();} NJWA3zz   
catch(Exception e){e.printStackTrace ();} I-]?"Q7Jz  
} .ypL=~Rp  
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//读取保存的下载信息（文件指针位置） Y!w`YYKP  
private void read_nPos() z!ZtzD]cb  
{ h+g_rvIG*  
try{ N/"{.3{W  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 84& $^lNV  
int nCount = input.readInt(); |4;Fd9q^m  
nStartPos = new long[nCount]; ,~N/- 5  
nEndPos = new long[nCount]; IL#"~D?
  
for(int i=0;i<nStartPos.length;i++) wDal5GJp  
{ l[0RgO*S  
nStartPos = input.readLong(); k8&;lgO'  
nEndPos = input.readLong(); HdUQCugxx:  
} &[?\k>  
input.close(); :+^lJ&{U  
} [ )Iv^ U9  
catch(IOException e){e.printStackTrace ();} Hw}Xbp[y  
catch(Exception e){e.printStackTrace ();} l*Gvf_UH  
} @zW]2 c   
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+SR+gE\s0  
private void processErrorCode(int nErrorCode) t&C1Oo}=3  
{ _7Ju  
System.err.println("Error Code : " + nErrorCode); ] vHF~|/-  
} > PRFWO  
;#W2|'HD  
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//停止文件下载 u5`u>.!  
public void siteStop() Q%`@0#"]Sv  
{ 6jD=F ^jw  
bStop = true; r= `Jn6@  
for(int i=0;i<nStartPos.length;i++) PbJ(:`u  
fileSplitterFetch.splitterStop(); we//|fA<  
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} ]nn
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} S%;O+eFY
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//负责部分文件的抓取 i &nSh ]KK  
**FileSplitterFetch.java iy.p n  
*/ G"qvz{*  
package NetFox; {L{o]Ii?g  
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import java.io.*; %v M-mbX  
import java.net.*; Ju@c~Xm  
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public class FileSplitterFetch extends Thread { *aM=Z+  

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String sURL; //File URL O m|_{  
long nStartPos; //File Snippet Start Position `KoV_2|  
long nEndPos; //File Snippet End Position "<N*"euH  
int nThreadID; //Thread's ID 8b&/k8i:  
boolean bDownOver = false; //Downing is over I{C SH  
boolean bStop = false; //Stop identical DMr\ TN  
FileAccessI fileAccessI = null; //File Access interface oWT3apGO  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException r(TIw%L$  
{ q 'yva  
this.sURL = sURL; A:%`wX}  
this.nStartPos = nStart; rH Lm\3  
this.nEndPos = nEnd; &jJL"gq"  
nThreadID = id; 6Pl<'3&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 MAR'y8I  
} Gx/Oi)&/  
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public void run() >1Ibc=}g  
{ E<Y$>uKA  
while(nStartPos < nEndPos && !bStop) GR_-9}jQP  
{ `4J$Et%S  
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try{ Rr]Hy^w  
URL url = new URL(sURL); tXs\R(?T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Se}c[|8  
httpConnection.setRequestProperty("User-Agent","NetFox"); zY{A'<\O  
String sProperty = "bytes="+nStartPos+"-"; jvL[ JI,b  
httpConnection.setRequestProperty("RANGE",sProperty); Ynj,pl  
Utility.log(sProperty); TF\C@4Z  
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InputStream input = httpConnection.getInputStream(); U?Zq6_M&  
//logResponseHead(httpConnection); 6<QQ@5_  
@
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byte[] b = new byte[1024]; *w\W/Y  
int nRead; -GrE}L  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *L^,|   
{ Z@S3ZGe  
nStartPos += fileAccessI.write(b,0,nRead); .|70;  
//if(nThreadID == 1) |0b`fOS  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i[3'ec3  
} kgP0x-Ap  
aB&&YlR=n<  
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Utility.log("Thread " + nThreadID + " is over!"); !*N@ZL&X  
bDownOver = true; Bnxm HGP#&  
//nPos = fileAccessI.write (b,0,nRead); F^;ez/Gl  
} V b?oJhR  
catch(Exception e){e.printStackTrace ();} X.{S*E:$u  
} \~$#1D1f  
} [RhO$c$[\  
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#q=Efn
'  
//打印回应的头信息 +a+Om73B2  
public void logResponseHead(HttpURLConnection con) ^hM4j{
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{ dUZ ,m9u  
for(int i=1;;i++) Zb>?8  
{ <\^8fn  
String header=con.getHeaderFieldKey(i);
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if(header!=null) VY4yS*y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); sDlO#  
Utility.log(header+" : "+con.getHeaderField(header)); yvB.&<]No  
else Z@!+v19^  
break; e*NnVys  
} !_)[/q"  
} VpDbHAg  
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public void splitterStop() ggR.4&<  
{ gjDHo$  
bStop = true; HIZe0%WPw  
} Kn1a>fLaJ_  
E ~<JC"]  
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} '5$b-x6F  
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%IWPM"  
/* 2FJ*f/  
**FileAccess.java ^<2p~h0 \  
*//文件访问(定位，写) 3f{3NzN  
package NetFox; lt8|9"9<  
import java.io.*; @Jw-8Q{  
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public class FileAccessI implements Serializable{ F={a;Dvrn  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 83#mB:^R  
RandomAccessFile oSavedFile; }o`76rDN  
long nPos; (f"4,b^]  
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public FileAccessI() throws IOException !+v$)3u9  
{ o>pJPV  
this("",0); SwMc pNo  
} |CRn c:  
*$g-:ILRuZ  
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public FileAccessI(String sName,long nPos) throws IOException $>LQ6|XRu  
{ X
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oSavedFile = new RandomAccessFile(sName,"rw"); wFZP,fQ9l  
this.nPos = nPos; .?$gpM?i  
oSavedFile.seek(nPos); 4.t-i5
  
}
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vdwsJPFbc  
public synchronized int write(byte[] b,int nStart,int nLen) Gk6iIK  
{ >z@0.pN]7  
int n = -1; ZJiG!+-j  
try{ S)@j6(HC4  
oSavedFile.write(b,nStart,nLen); sQZhXaMa $  
n = nLen; 9G2FsM|,  
} I; rGD^  
catch(IOException e) c]!V'#U  
{ WH^%:4  
e.printStackTrace (); a\*yZlXKs  
} 5nx1i  
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,z=LY5_z)  
return n; Qo|\-y-#  
} tKXIk9e  
*s3/!K  
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} X"eYK/7  
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r9?Mw06Wc5  
/* JB<t6+"rD  
**SiteInfoBean.java Jln:`!#fDf  
*/ N
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package NetFox; tQ#n${a@f  
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YGNP53CU  
public class SiteInfoBean { do'GlU oMC  
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private String sSiteURL; //Site's URL wUJcmM;  
private String sFilePath; //Saved File's Path r5^eNg k  
private String sFileName; //Saved File's Name =Dj#gV  
private int nSplitter; //Count of Splited Downloading File UJ2U1H54h  
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4^<?Wq~  
public SiteInfoBean() n+M<\  
{//nSplitter的缺省值为5 !dq.KwL  
//default value of nSplitter is 5 "#g}ve,  
this("","","",5); E!F^H^~$8  
} &UFZS94@r  
~wdGd+ez  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gjlx~.0d  
{ +lTq^
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sSiteURL= sURL; \Vk:93OH21  
sFilePath = sPath; Q+{n-? :  
sFileName = sName; Nz-&MS  
this.nSplitter = nSpiltter; );YDtGip J  
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} 2~[juWbz  
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public String getSSiteURL() o2ECG`^b  
{
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return sSiteURL; 8{ I|$*nB  
} #\ErY3k6&  
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s>c=c-SP.  
public void setSSiteURL(String value) k}rbim  
{ }6ldjCT/,  
sSiteURL = value; % ]U  
} vP,n(reM  
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public String getSFilePath() "J1 4C9u   
{ "r2 r  
return sFilePath; 2fS:- 8N  
} vih9KBT  
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public void setSFilePath(String value) 4I[P>  
{ B<C&xDRZ0  
sFilePath = value; 2`-Bs  
} bI`g|v  
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public String getSFileName() \{YU wKK/A  
{ ugBCBr  
return sFileName;
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} }-`4DHgq  
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public void setSFileName(String value) z(~_AN M4,  
{ E*lx
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sFileName = value; moE2G?R  
} eJX#@`K  
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public int getNSplitter() *NQ/UXE  
{ V.2_i*  
return nSplitter; e}W)LPR!  
} H"F29Pu2  
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public void setNSplitter(int nCount) 'hf8ZEW9'  
{ yDh6KUK  
nSplitter = nCount; D/' dTrR  
} {c0`Um3&>  
} 4P
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2t,zLwBdnJ  
/* 6w77YTJ  
**Utility.java *z2s$EZ  
*/ *lb<$E]="!  
package NetFox; Q59W#e)  
t$ *0{w E  
@o.I;}*
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public class Utility { )pn3~t<ed  

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public Utility() `$NP>%J-  
{ ?h2}#wg  
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y
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} WEpoBP CL  
V43H/hl  
//线程睡眠 )`}:8y?  
public static void sleep(int nSecond) y+;|
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{ R}ecc  
try{ !!ya  
Thread.sleep(nSecond); .wr>]yN  
} nj4/#W  
catch(Exception e) i mM_H;-X  
{ 0CvUc>Pj`"  
e.printStackTrace (); D`AsRd  
} H)&R=s  
} ItCv.yv35  
:Qq#Z  
//日志 mA}"a<0  
public static void log(String sMsg) -']56o_sQ/  
{ ^C%<l(b  
System.err.println(sMsg); \Og+c%  
} B-ESFATc  
"w_aM7x_  
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public static void log(int sMsg) 'f|o{  
{ L rPkxmR  
System.err.println(sMsg); y?!"6t7&  
} 4.(4x&  
} *|l/6!WM  
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<7$1kGlA  
/* ^}C\zW  
**TestMethod.java SY8C4vb'h  
*/ B\n[.(].r  
package NetFox; F5#YOck&,  
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public class TestMethod { )CyS#j#=  
2BobH_H  
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public TestMethod() b>$S<td  
{ ///xx/weblogic60b2_win.exe !%>7Dw(kt  
try{  LIdF 0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iR0y"Cii  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O1kl70,`R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]{LjRSV
 
fileFetch.start(); +^<](z  
} cGD(.=  
catch(Exception e){e.printStackTrace ();} \C1nZk?3  
,=N.FS  
$7uA%|\  
} HorDNRyu  
p<;0g9,1  
#D|p2L$  
public static void main(String[] args) iyog`s c  
{ Xry47a )  
new TestMethod(); %07SFu#  
} l@:0e]8|o  
} V1JIht>Opo  
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