http断点续传简单实现（java)

/* e w^(3&  
**SiteFileFetch.java "yn~axk7  
*/ 4xy\  
package NetFox;
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import java.io.*; 37#&:[w>  
import java.net.*; ALF0d|>=uj  
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public class SiteFileFetch extends Thread { ^|]&"OaB Z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~wvt:E,fC  
long[] nStartPos; //开始位置 tcD7OC:"6  
long[] nEndPos; //结束位置 eA/n.V$z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 K`4rUEf}V"  
long nFileLength; //文件长度 M&Uy42,MR  
boolean bFirst = true; //是否第一次取文件 Wh[QR-7Ew  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 8Sbz)X  
DataOutputStream output; //输出到文件的输出流 mzgt>Qtkz=  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7#V7D6j1  
public SiteFileFetch(SiteInfoBean bean) throws IOException ZlT }cA/n  
{ Y-
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siteInfoBean = bean; -;""l{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); pwFp<O"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); '\:4Ijp<"  
if(tmpFile.exists ()) O[@!1SKT0  
{ N5 ME_)  
bFirst = false; H4$qM_N  
read_nPos();  ~?ab_CY  
} K$"#SZEi  
else > I2rj2M#  
{ TCr4-"`r-{  
nStartPos = new long[bean.getNSplitter()]; j3j?2#vR  
nEndPos = new long[bean.getNSplitter()]; @HT\Y%E  
} AIF?>wgq  
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} /6x&%G:m#  
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public void run() 4T
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{ Sj+H{xJi  
//获得文件长度 pUIN`ya[[  
//分割文件 :F(4&e=w  
//实例FileSplitterFetch Jo?LPR \6  
//启动FileSplitterFetch线程 727#7Bo  
//等待子线程返回 I _nQTWcm  
try{ M2$/x`\-~  
if(bFirst) &<&tdShI  
{ ]OAU&t{  
nFileLength = getFileSize(); Cbbdq%ySI  
if(nFileLength == -1) $BqiC!~  
{ wNB?3
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System.err.println("File Length is not known!"); <=(K'eqC^  
} 7e_4sxg'(3  
else if(nFileLength == -2) Yuv(4a<M%  
{ Ly=.  
System.err.println("File is not access!"); vNO&0~  
} Gp9 <LB\,  
else K\xz|Gq  
{ N,`@
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for(int i=0;i<nStartPos.length;i++) "4b{YWv  
{ &3vm @  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); y?sz&*:  
} I4Do$&9<D  
for(int i=0;i<nEndPos.length-1;i++) ?1Nz ,Lc$  
{ snbXAx1L  
nEndPos = nStartPos[i+1]; qq)5)S  
} $z=a+t *  
nEndPos[nEndPos.length-1] = nFileLength; 2;)IBvK  
} G|cjI*  
} *|&Y ,H?  
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//启动子线程 }T_"Vg q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ydWr&E5  
for(int i=0;i<nStartPos.length;i++) Df"PNUwA"  
{ Tzd#!Lvm:,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :tWkK$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xI,3(A.  
nStartPos,nEndPos,i); 7mt
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5;`Ot2  
fileSplitterFetch.start(); FH</[7f;@N  
} ximVh}'a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F=\ REq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6AIq
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _DR@P(0>_  
nEndPos = " + nFileLength); >VhZv75  
// fileSplitterFetch[nPos.length-1].start(); gj|5"'g%  
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//等待子线程结束 (-ELxshd  
//int count = 0; JCH9~n.  
//是否结束while循环 2K4Xu9-i:b  
boolean breakWhile = false; ll__A|JQ  
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while(!bStop) !S~)U{SSK  
{ TY/'E#.  
write_nPos(); IAA_Ft  
Utility.sleep(500); ,wf_o%'eW  
breakWhile = true; 2fdN@iruB  
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for(int i=0;i<nStartPos.length;i++) Ew4D';&;  
{ $c*fbBM(&n  
if(!fileSplitterFetch.bDownOver) wmpQF<  
{ sudh=_+>  
breakWhile = false; '7' 73  
break; w#2apaz  
} 0~<?*{~  
} 2V8"jc  
if(breakWhile) kM-8%a2i  
break; xJ#O|7N  
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//count++; Ud"_[JtGM  
//if(count>4) [cFD\"gJAr  
// siteStop(); wo62R&ac  
} 0rX%z$D+@  
};rEN`L  
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System.err.println("文件下载结束！"); [4EIy
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} o^5UHFxTCB  
catch(Exception e){e.printStackTrace ();} W rT_7  
} CVY-U|xFY  
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//获得文件长度 F)=<|,b1  
public long getFileSize() a^G>|+8  
{ b L.Xby<Y  
int nFileLength = -1; ao7M(f  
try{ ZCK#=:ln  
URL url = new URL(siteInfoBean.getSSiteURL()); rD6NUS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ui"`c%2n  
httpConnection.setRequestProperty("User-Agent","NetFox"); j0F& WKk  
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int responseCode=httpConnection.getResponseCode(); ! qtj1.w  
if(responseCode>=400) A\"4[PXpQ  
{ sj+
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processErrorCode(responseCode); F)l1%FCm  
return -2; //-2 represent access is error 'D[ *|Qcy  
} 0/fwAp
 
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String sHeader; %}  
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for(int i=1;;i++) svCm}`  
{ -hK^*vJ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Qc Xw -  
//Utility.log(in.readLine()); kT^`j^Jr  
sHeader=httpConnection.getHeaderFieldKey(i); bHDZ=Ik  
if(sHeader!=null) ?Rh[S  
{ ip|l3m$Mi  
if(sHeader.equals("Content-Length")) p%Ns f[1>  
{ W Emh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \  6Y%z  
break; q)"yP\  
} u\K`TWb%  
} EBmkKiI;  
else V' sq'XB  
break; <?rd
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} -9
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} BI>r'  
catch(IOException e){e.printStackTrace ();} m*AiP]Qu  
catch(Exception e){e.printStackTrace ();} 2"
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/7R0w  
Utility.log(nFileLength); OV^?cA  
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return nFileLength; 7MX5hZF"  
} YB9)v5Nz(  
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//保存下载信息（文件指针位置） .V{y9e+  
private void write_nPos() .|LY /q\A  
{ ;C5 J^xHI  
try{ Q/
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ZY)&Fam}  
output.writeInt(nStartPos.length); \lpvRZ\L&g  
for(int i=0;i<nStartPos.length;i++) WQNFHRfO*n  
{ k|rbh.Q  
// output.writeLong(nPos); 5Kkp1K$M  
output.writeLong(fileSplitterFetch.nStartPos); j[$+hh3:  
output.writeLong(fileSplitterFetch.nEndPos); nhB.>ReAi  
} ^}Gu'!z9D  
output.close(); UmP\;
 
} Gr|102  
catch(IOException e){e.printStackTrace ();} 7;ddzxR4  
catch(Exception e){e.printStackTrace ();} o=Kd9I#  
} p~<d8n4UH  
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//读取保存的下载信息（文件指针位置） Dp;6CGYl?  
private void read_nPos() ByW,YKMy  
{ ,z
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try{ 0?,%B?A8O  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wGx*Xy1n<  
int nCount = input.readInt(); QzD8 jk#  
nStartPos = new long[nCount]; MMyJAGh ^G  
nEndPos = new long[nCount]; \aGTi pB  
for(int i=0;i<nStartPos.length;i++) w4;1 ('  
{ j<-YK4.t  
nStartPos = input.readLong(); @<=<?T>1  
nEndPos = input.readLong(); l'#a2Pl  
} ),U>AiF]  
input.close(); -e_L2<7  
} ]t.6bb4  
catch(IOException e){e.printStackTrace ();} h$a%PaVf  
catch(Exception e){e.printStackTrace ();} 4w(#`'I>  
} p7]V1w:  
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private void processErrorCode(int nErrorCode) nrRP1`!]T  
{ = GZ,P (
  
System.err.println("Error Code : " + nErrorCode); 0tp3mYd  
} N&-J,p~  
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&265 B_'D  
//停止文件下载 I@o42%w2  
public void siteStop() H 5'Ke+4.e  
{ ibQN pIz  
bStop = true; 05/'qf7P,U  
for(int i=0;i<nStartPos.length;i++) z3Q#Wmv2  
fileSplitterFetch.splitterStop(); v0'`K 5M  
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} FR? \H"'x  
} xHi.N*~D  
//负责部分文件的抓取 ~SR9*<  
**FileSplitterFetch.java /zZ";4  
*/ -5sKJt]+i  
package NetFox; hYEUiQ  
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import java.io.*; .|z8WF*  
import java.net.*; *_CzCl^   
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public class FileSplitterFetch extends Thread { |++\"g  
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String sURL; //File URL qpXsQim$~  
long nStartPos; //File Snippet Start Position &_W~d0  
long nEndPos; //File Snippet End Position b_rHt s  
int nThreadID; //Thread's ID d@e2+3<  
boolean bDownOver = false; //Downing is over r%UsUj  
boolean bStop = false; //Stop identical rs+ ["h  
FileAccessI fileAccessI = null; //File Access interface 'jj|bN  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <%GfF![v  
{ 
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this.sURL = sURL; /+ Q3JS(  
this.nStartPos = nStart; cPbAR'  
this.nEndPos = nEnd; x#c%+  
nThreadID = id; bTbF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 tv'=xDCp  
} c4Wl^E8  
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public void run() !@4 i:,p@  
{ L5 Q^cY]p  
while(nStartPos < nEndPos && !bStop) Z)'gj  
{ l _gJC.  
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S:8 WBY]M  
try{ pxb4x#CC  
URL url = new URL(sURL); 9>T5~C'*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rBUWzpE"  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8T?D#,/  
String sProperty = "bytes="+nStartPos+"-"; L6Io u  
httpConnection.setRequestProperty("RANGE",sProperty); ODNZLCB~t  
Utility.log(sProperty); 0S2/,[-u+  
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InputStream input = httpConnection.getInputStream(); Z]08gH  
//logResponseHead(httpConnection); kJK*wq]U6  
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byte[] b = new byte[1024]; G.3yuok9
 
int nRead; D`R~d;U~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `!Yd$=*c_&  
{ .,F`*JVFq  
nStartPos += fileAccessI.write(b,0,nRead);
 )fQ1U  
//if(nThreadID == 1) JA~q}C7A7o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Lu CiO  
} N;gY5;0m  
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Utility.log("Thread " + nThreadID + " is over!"); 0Ua&_D"  
bDownOver = true; PUmgcMt  
//nPos = fileAccessI.write (b,0,nRead); FxmHy{JG  
} V{UY_ e8W  
catch(Exception e){e.printStackTrace ();} x;{Hd;<YF  
} NG_7jZzXA9  
} Mj`g84  
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+U)4V}S)  
//打印回应的头信息 >&ENrvaJ  
public void logResponseHead(HttpURLConnection con) $,zW0</P*l  
{ V1haAP[#  
for(int i=1;;i++) u|LDN*#DW  
{ =Cd{bj.8  
String header=con.getHeaderFieldKey(i); Qk >
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if(header!=null) Z/czAr@4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); X;n09 L`CB  
Utility.log(header+" : "+con.getHeaderField(header)); z*B?Hw),  
else Y"L|D,ex  
break; WLA&K]  
} [bw1!X3  
} U\(71=  
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w{ ;Sp?Os  
public void splitterStop() @]!9;?so  
{ =3ovaP  
bStop = true; `~z[Hj=2  
} TF9A4  
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} 4jSYR#Hqp`  
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/* r@/@b
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**FileAccess.java ,,!P-kK$  
*//文件访问(定位，写) p8 Ao{  
package NetFox; U>OAtiq JX  
import java.io.*; li,rPUCt  
r6kJV4I=re  
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public class FileAccessI implements Serializable{ ALV(fv$cD  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |}.}q  
RandomAccessFile oSavedFile; P@f#DX )  
long nPos; |j81?4<)v  
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public FileAccessI() throws IOException !l=)$RJKdD  
{ ]Vmo>  
this("",0); iEZ+Znon  
} N#ZWW6  
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public FileAccessI(String sName,long nPos) throws IOException ~\AF\n%  
{ :o .+<_&  
oSavedFile = new RandomAccessFile(sName,"rw"); Fi67"*gE  
this.nPos = nPos; @"MQ6u G>  
oSavedFile.seek(nPos); tv.<pP9-C  
} k@un}}0r  
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public synchronized int write(byte[] b,int nStart,int nLen) R^$|D)(  
{ ;Xy=;Z.]
i  
int n = -1; 2,F9P+  
try{ '5
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oSavedFile.write(b,nStart,nLen); as|w} $  
n = nLen; gFKJbjT|  
} DJ@n$G`^^  
catch(IOException e) 9O:l0 l  
{ P!E2.K,  
e.printStackTrace ();
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} ^a_a%ws
 
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return n; Hj|&P/jY]*  
} giX[2`^NG  
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} m;]wKd"  
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/* T"W<l4i-  
**SiteInfoBean.java )\=
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*/ >e>3:~&2  
package NetFox; '2*OrY  
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public class SiteInfoBean { Ly+UY.v"  
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private String sSiteURL; //Site's URL 0DmA3  
private String sFilePath; //Saved File's Path mGj)Zrx>  
private String sFileName; //Saved File's Name 5M~{MdF|.  
private int nSplitter; //Count of Splited Downloading File `a4&_`E,p  
5b7(^T^K  
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public SiteInfoBean() 'R79,)|;[  
{//nSplitter的缺省值为5 B5;%R01A  
//default value of nSplitter is 5 () _RLA  
this("","","",5); q[a\a7U z  
} su1lv#
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) phuiLW{&  
{ k.ou$mIY  
sSiteURL= sURL; X3l>GeUi  
sFilePath = sPath; /{i~-DVME
 
sFileName = sName; dZ`Y>wH_  
this.nSplitter = nSpiltter; @%Ld\8vdfJ  
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} |l; Ot=C=  
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public String getSSiteURL() 9j>2C  
{ 5-|!mSd  
return sSiteURL; Fvl\.  
} S{+t>en  
JX=rL6Y@:;  
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public void setSSiteURL(String value) \%a0Lp{ I  
{ 89FAh6uE  
sSiteURL = value; ,=u;1  
} sm/aL^4  
?%  24M\  
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public String getSFilePath() "/Qz?1>l+  
{ c| ^I}  
return sFilePath; "[_j8,t`  
} 1&=)Bxg4  
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public void setSFilePath(String value) hu}$\  
{ PXMd=,}  
sFilePath = value; odhS0+d^  
} = j1Jl^[  
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public String getSFileName() >3uNh:|>/  
{ ,eyh%k*hz  
return sFileName; 8_('[89m  
} t eY@)F  
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9&Jf4lC94  
public void setSFileName(String value) &>JP.//spi  
{ QoZV6  
sFileName = value; %10ONe}  
} #rkq ?:Q  
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public int getNSplitter() Z =+Z96  
{ 5kiW@{m  
return nSplitter;  k[r^@|  
} kUd]8Ff!  
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public void setNSplitter(int nCount) Z2g'&,uc#  
{ |.N[NY
  
nSplitter = nCount; d_!Z /M,  
} S<0 &V  
} eY<<Hld  
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/* 7}
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**Utility.java l0Q5q)U1A  
*/ 2ioHhcYdJU  
package NetFox; TjUwe@&Rw  
.?:*0
 
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public class Utility { #t ;`  
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public Utility() 4IeCb?  
{ ot}erC2~  
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} p'R<yB)V  
-<#) ]um  
//线程睡眠 ? :H+j6+f  
public static void sleep(int nSecond) HRf;bKZ  
{ ,2M}qs"P7G  
try{ k\f _\pj6  
Thread.sleep(nSecond); #3&@FzD_P  
} U{2xgNJ  
catch(Exception e) luoQ#1F?sl  
{ *tXyd<_
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e.printStackTrace (); $.`o  
} 0S{23L4C  
}
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//日志 Q %o@s3~O  
public static void log(String sMsg) H>TO8;5(  
{ *ID=X!v  
System.err.println(sMsg); 'z$N{p4
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} Y1PR?c Q  
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public static void log(int sMsg) `5Y*) q  
{ ~gI%lORqN  
System.err.println(sMsg);
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} *'Yy@T8M  
} \|HtE(uCM1  
@A,8>0+  
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/* qAjtvc2  
**TestMethod.java ~]KdsT(=_  
*/ {)" 3  
package NetFox; zhn?;Fi  
t
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public class TestMethod { =$'>VPQ  
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public TestMethod() _(m72o0g>>  
{ ///xx/weblogic60b2_win.exe Sz0PZtJ  
try{ ]Uv,}W  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @\by`3*Q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V(S7mA:T  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
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fileFetch.start(); un "I  
} %2 r~  
catch(Exception e){e.printStackTrace ();} SEgw!2H  
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opa/
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} XFhH+4#]  
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public static void main(String[] args) j7!u;K^c  
{ IyO0~Vx>  
new TestMethod(); T}Tv}~!f  
} 5_9`v@-4_  
} \,;glY=M!  
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