http断点续传简单实现（java)

/* 98| v.d  
**SiteFileFetch.java CB,2BTtRE  
*/ $aB`A$'hK  
package NetFox; oM^vJ3  
import java.io.*; Q4*{+$A  
import java.net.*; &/2+'wCp5  
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public class SiteFileFetch extends Thread { 2L[!~h2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean auX(d -m  
long[] nStartPos; //开始位置 bA2[=6  
long[] nEndPos; //结束位置 PhV/WjCZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X8}\m%gCU  
long nFileLength; //文件长度 *GY8#Az  
boolean bFirst = true; //是否第一次取文件 =Ti@Y  
boolean bStop = false; //停止标志 z_'!?
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File tmpFile; //文件下载的临时信息 t^>P,%$  
DataOutputStream output; //输出到文件的输出流 V2AsZc0U(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \,n X
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public SiteFileFetch(SiteInfoBean bean) throws IOException EE|c@M^  
{ ;$1x_ Cb  
siteInfoBean = bean; 2A =Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X[dH*PV  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^!i4d))  
if(tmpFile.exists ()) -{J0~1'#-  
{ ?~T(Cue>  
bFirst = false; +4W
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read_nPos(); m8x?`Gw~jw  
} %K8YZc(&  
else t6`(9o@}  
{ 0H.bRk/P+  
nStartPos = new long[bean.getNSplitter()]; kka{u[ruA  
nEndPos = new long[bean.getNSplitter()]; $;}@2U   
} 0-aaLC~Z>  
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} hR:i!  
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public void run() +t1+1Zv  
{ QmGK! H>3  
//获得文件长度 \o3s&{+y,  
//分割文件 l-20X{$m:  
//实例FileSplitterFetch "X._:||8  
//启动FileSplitterFetch线程 U(x$&um(l  
//等待子线程返回 zFipuG0
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try{ 8 $H\b &u  
if(bFirst) ]]`[tVaFr  
{ Z,\(bW qF  
nFileLength = getFileSize(); R
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if(nFileLength == -1) =h=-&DSA  
{ `1Md1e:J  
System.err.println("File Length is not known!"); >ifys)wg>  
} zVe,HKF/  
else if(nFileLength == -2) &U=_:]/  
{ #nft{AN  
System.err.println("File is not access!"); h
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} x
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else ._;It198f  
{ =w8 0y'  
for(int i=0;i<nStartPos.length;i++) lA4J#  
{ 38l:Y"  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  xiQc\k$  
} "?<`]WG\  
for(int i=0;i<nEndPos.length-1;i++) /#"9!8%V  
{ >b#CR/^z  
nEndPos = nStartPos[i+1]; X}h}3+V  
} UUtSme  
nEndPos[nEndPos.length-1] = nFileLength; .wWf#bB  
} qC& xuu|  
} 4DP<)KX  
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//启动子线程 FEopNDy@y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; n>:e8KVM;  
for(int i=0;i<nStartPos.length;i++) qPUACuF'  
{ ;Z;` BGZJ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cFJZ|Ld  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Bd;EI)J
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nStartPos,nEndPos,i); yDe*-N\'W  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L"?4}U:  
fileSplitterFetch.start(); L8zMzm=-  
} JJM!pD\h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0|0IIgy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,m7Z w_.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9!2$?xqym  
nEndPos = " + nFileLength); -sle7k  
// fileSplitterFetch[nPos.length-1].start(); zH~g5xgh  
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6"rS?>W/mO  
//等待子线程结束 FcOrA3tt  
//int count = 0; |\"%Dy[m  
//是否结束while循环 i*
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boolean breakWhile = false; \Km+>G  
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while(!bStop) j *N^.2  
{ kZ:~m1dd  
write_nPos(); KO}TCa  
Utility.sleep(500); -W})<{End  
breakWhile = true; #a8i($k{e  
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for(int i=0;i<nStartPos.length;i++) ;t@^Z_z,CR  
{ d)$seZB  
if(!fileSplitterFetch.bDownOver) %F;uW[4r  
{ w#bdb;  
breakWhile = false; (~b0-3s  
break; Na.e1A&?j  
} :4"b(L  
} #X5Tt  ;  
if(breakWhile) /wHfc[b>  
break; MpIP)bdq7  
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//count++; +J}h  
//if(count>4) )$2h:dw_  
// siteStop(); (1Jc-`  
} ^c sOXP=Yp  
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System.err.println("文件下载结束！"); 
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} S8]YS@@D   
catch(Exception e){e.printStackTrace ();} cW^u4%f't'  
} FvBnmYnW  
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//获得文件长度 H<`7){iG  
public long getFileSize() )VxC v
  
{ |c,'0V,"cH  
int nFileLength = -1; ob(~4H-
 
try{ 3HX-lg`0  
URL url = new URL(siteInfoBean.getSSiteURL()); Vvl8P|x.<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I{u+=0^Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); L0xh?B  
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int responseCode=httpConnection.getResponseCode(); NUX2{8gs  
if(responseCode>=400) xa%2w]  
{ +r__>V,  
processErrorCode(responseCode); rJcZ a#  
return -2; //-2 represent access is error *3!ixDX[r  
} x*F_XE1#M  
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String sHeader; 0kld77tn 2  
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for(int i=1;;i++) !X/O1PM|  
{ --|L?-2k,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A ]~%<=b  
//Utility.log(in.readLine()); ~C;gEE-  
sHeader=httpConnection.getHeaderFieldKey(i); v@]\ P<E  
if(sHeader!=null) r1Cq8vD*m  
{ j2,w1f}T  
if(sHeader.equals("Content-Length")) YU%U  
{ ^o6&|q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9TOq
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break; FKu^{'Y6E0  
} V']
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} }VXZM7@u  
else `}&}2k  
break; LDq(WPI1#  
} nM&UdKf3  
} )u(Dqu\t  
catch(IOException e){e.printStackTrace ();} bmGtYv  
catch(Exception e){e.printStackTrace ();} GxcW^{;  
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Utility.log(nFileLength); B"fKv0  
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return nFileLength; 91j.%#[v'  
} t_ZWd#x+;  
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//保存下载信息（文件指针位置） F6 c1YI[  
private void write_nPos()  8&KqrA86  
{ 8n)3'ok  
try{ pj9s=}1 '  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,O]AB  
output.writeInt(nStartPos.length); ?;)F_aHp  
for(int i=0;i<nStartPos.length;i++) lC(g&(\{  
{ QF`o%mI  
// output.writeLong(nPos); uNRT@@oCq  
output.writeLong(fileSplitterFetch.nStartPos); /:@X<  
output.writeLong(fileSplitterFetch.nEndPos); Luu.p<   
} #sp8 !8|y  
output.close(); 2XGbqZj  
} i5^U1K\M  
catch(IOException e){e.printStackTrace ();} W8{zV_TB
m  
catch(Exception e){e.printStackTrace ();} 0ud>oh4WPR  
} H@hHEzO  
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//读取保存的下载信息（文件指针位置） #^oF^!  
private void read_nPos() @Tg+Kt  
{ eMV@er|  
try{ 8|iMD1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); tM;S )S(=  
int nCount = input.readInt(); P_3U4J  
nStartPos = new long[nCount]; $y&1.caMa  
nEndPos = new long[nCount]; [E/}-m6g  
for(int i=0;i<nStartPos.length;i++) )!(etB=`y  
{ AilfeHG  
nStartPos = input.readLong(); $*i"rlJC  
nEndPos = input.readLong(); _ 0Ced&i  
} |Zrkk>GW:  
input.close(); R~&i8n.  
} d8Kxtg Y  
catch(IOException e){e.printStackTrace ();} =C.WM*='  
catch(Exception e){e.printStackTrace ();}  @s@67\  
} 5.e. BT  
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private void processErrorCode(int nErrorCode) v<U +&D{  
{ M~&X?/8  
System.err.println("Error Code : " + nErrorCode); >E3 lY/[  
} <<[hZ$.  
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*=ymK*  
//停止文件下载 r@m2foaO  
public void siteStop() 2r|!:^'?W  
{ wk"zpI7L  
bStop = true; k_<8SG+`  
for(int i=0;i<nStartPos.length;i++) #XlE_XD  
fileSplitterFetch.splitterStop(); `2Oh0{x0*O  

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} fCxF3m(O  
} *PV
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//负责部分文件的抓取 +w pe<T  
**FileSplitterFetch.java d(-$ { c  
*/ |6.1uRFE2  
package NetFox; :'LG%E:b  
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import java.io.*; IN%04~=H  
import java.net.*; ;c_pa0L  
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public class FileSplitterFetch extends Thread { )4P5i b  
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String sURL; //File URL ].eY]o}=  
long nStartPos; //File Snippet Start Position 1#3 Qa{i  
long nEndPos; //File Snippet End Position BsX# ~  
int nThreadID; //Thread's ID SLze) ?.  
boolean bDownOver = false; //Downing is over Lx"a#rZ  
boolean bStop = false; //Stop identical 4{r_EV[(  
FileAccessI fileAccessI = null; //File Access interface q;V1fogqI)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !F|iL  
{ !B3lsXLSY  
this.sURL = sURL; hoQ?8}r:  
this.nStartPos = nStart; c.\J_^  
this.nEndPos = nEnd; fii\&p7z  
nThreadID = id;  Dy[ YL  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *I}_
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} D@ji1$K  
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public void run() UT9=S21  
{ j;k(AM<  
while(nStartPos < nEndPos && !bStop) 92k}ON  
{ -~HlME*~f  
e]+ [lq\p@  
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try{ DjT ekn  
URL url = new URL(sURL); D=fB&7%@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dIo|i,-  
httpConnection.setRequestProperty("User-Agent","NetFox"); nAp7X-t  
String sProperty = "bytes="+nStartPos+"-"; N3};M~\  
httpConnection.setRequestProperty("RANGE",sProperty); Mlpq2I_x  
Utility.log(sProperty); 2rw<]Ce  
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InputStream input = httpConnection.getInputStream(); pP'-}%  
//logResponseHead(httpConnection); z^
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byte[] b = new byte[1024]; a`w)awb  
int nRead; Kup-O u,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >Q~"/-bN)  
{ !HXdUAKu  
nStartPos += fileAccessI.write(b,0,nRead); +M\*C#  
//if(nThreadID == 1) L#e|t0'#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BX),
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} K6,5C0  
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Utility.log("Thread " + nThreadID + " is over!"); (WW,]#^  
bDownOver = true; "gCSbMq(Vq  
//nPos = fileAccessI.write (b,0,nRead); S)"5X)mq  
} |7zm!^t$  
catch(Exception e){e.printStackTrace ();} ]sjOn?YA+  
} 2="C6 7TK  
} 'FBvAk6  
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l!ye\
 
//打印回应的头信息 aAko-,URC  
public void logResponseHead(HttpURLConnection con) !qH=l-7A  
{ MjU>qx::  
for(int i=1;;i++) {kJ[)7  
{ =*'X  
String header=con.getHeaderFieldKey(i); ftq~AF  
if(header!=null) 'q[V*4g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \]J"e%  
Utility.log(header+" : "+con.getHeaderField(header)); pAmTwe  
else U gB  
break; e7L;{+XI  
} LFSOHJj  
} su=.4JcK  
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public void splitterStop() LM
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{ j.CC.[$g  
bStop = true; YA^9, q6u?  
} CSU>nIE0  
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} HIhoYSwB  
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/* S0=BfkHi.  
**FileAccess.java *OF7{^~&  
*//文件访问(定位，写) 4r(rWlM  
package NetFox; l}AB):<Z  
import java.io.*; ^:-%tpB#!  
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public class FileAccessI implements Serializable{ kd\yHI9A  
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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 !s)2H/KM8  
RandomAccessFile oSavedFile; $]81s`  
long nPos; &8&WY1cU  
*pasI.2s#  
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public FileAccessI() throws IOException 1*-58N*  
{ n6o}$]H  
this("",0); 71/6=aq>n  
} <E\BKC%M  
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public FileAccessI(String sName,long nPos) throws IOException |E7]69=P  
{ ~`N|sI,  
oSavedFile = new RandomAccessFile(sName,"rw"); G8oQSo;D  
this.nPos = nPos; \+Cp<Hv+  
oSavedFile.seek(nPos); xDlC]loi7  
} :,VyOmf  
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public synchronized int write(byte[] b,int nStart,int nLen) eB]ZnJ2^=  
{ E0oJ|My  
int n = -1; Hh@mIusj  
try{ ac&tpvij  
oSavedFile.write(b,nStart,nLen); o!H"~5Trv!  
n = nLen; E>V8|Hz;  
} 5!cplx=<  
catch(IOException e) #-VKk  
{ N]=.I   
e.printStackTrace (); 0^[$0]Mt[  
} fg1 zT~  
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return n; uC;@Yi8  
} ss2:8up 99  
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} %Bo Jt-v  
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/* TMRXl.1  
**SiteInfoBean.java G![1+2p:Tq  
*/ \m.{^Xd~  
package NetFox; 0bd.e
ss  
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public class SiteInfoBean { 1IsR}uLh  
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private String sSiteURL; //Site's URL >%[W2L\'  
private String sFilePath; //Saved File's Path @O(\TIg  
private String sFileName; //Saved File's Name ``\H'^{B  
private int nSplitter; //Count of Splited Downloading File 7:;V[/  
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public SiteInfoBean() v]1rH$  
{//nSplitter的缺省值为5 6RtpB\hq  
//default value of nSplitter is 5 '\;tmD"N5#  
this("","","",5); 9(I4x]`  
} [gE2lfaEy  
oy |@m|J  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %$}iM<  
{ SVHtv0Nx  
sSiteURL= sURL; a&<<X:$Hy  
sFilePath = sPath; s6 ^JgdW  
sFileName = sName; lDA%M3(p  
this.nSplitter = nSpiltter; i}YnJ  
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} lV1|\~?4  
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public String getSSiteURL() $pKS['J0  
{ B
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return sSiteURL; WV% KoM,%  
} &0"`\~lA  
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public void setSSiteURL(String value) )2A4vU-IR.  
{ oa4}GNH  
sSiteURL = value; r5"/EMieh  
} E0|aI4S4  
*!Dzst-J3  
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public String getSFilePath() ;CrA  
{ A4^+p0@  
return sFilePath; 3m^BYr*y^  
} 'ZDclz9}  
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public void setSFilePath(String value) VuY.})+J:  
{ kmS8>O  
sFilePath = value; O<hHo]jLF  
} F~Li.qF  
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public String getSFileName() t&xx-4  
{ C/bttd  
return sFileName; P8jK yo  
} fin15k  
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public void setSFileName(String value) cm]]9z
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{ gr;M  
sFileName = value; ,jn?s^X6Dj  
} L`#+ZLo  
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^WNJQg'  
public int getNSplitter() A=$oYBB  
{ W)#`4a^xj7  
return nSplitter; 5c"kLq
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} E;q
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1
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public void setNSplitter(int nCount) /\#5\dHj  
{ I?>#neHc6  
nSplitter = nCount; <%z/6I Af|  
} B4}XK=)  
} q :bKT#\  
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/* p{rS -`I  
**Utility.java
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*/ "YL-!P  
package NetFox; :3B\,inJ  
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public class Utility { a%dx\&K  
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public Utility() AJT0)FCpR  
{ v\Ljm,+  
|
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} Ro<kp8
  
aW"!bAdx`,  
//线程睡眠  zjA/Z(  
public static void sleep(int nSecond) c #kV+n<  
{ jO55<s94  
try{ mV,R0olF  
Thread.sleep(nSecond); ^aXBt  
} X2cR+Ha0  
catch(Exception e) akQH+j  
{ rg,63r  
e.printStackTrace (); vNC0M:p,  
} ]D%k)<YK  
} T Rw6$CR  
$1+K}tP  
//日志 *K|aK p}  
public static void log(String sMsg) CWp1)%0=  
{ W[Bu&?h$  
System.err.println(sMsg); %K"%Qm=Tl  
} prtxE&-  
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public static void log(int sMsg) KeB4Pae|V  
{ Db(_T8sU  
System.err.println(sMsg); /BM1AV{s6  
} `fZD%o3l  
} Wq(l :W'  
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/* T3./V0]\I  
**TestMethod.java xXZKj  
*/ %i8>w:@NW  
package NetFox; Jv<$AI  
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B#"|5  
public class TestMethod { ^,lZ58 2  
hw$c@:pW;  
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public TestMethod() q9Sz7_K  
{ ///xx/weblogic60b2_win.exe ;9 ,mV(w  
try{ tvT8UW'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kQVDC,d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); liqR#<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -I-Uh{)j  
fileFetch.start(); W[E3P,XS  
} 3g[j%`k  
catch(Exception e){e.printStackTrace ();} neh;`7~5@K  
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} ^qO=~U!{  
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public static void main(String[] args) RP,:[}mPl  
{ RO{@RhnV  
new TestMethod(); #RM3^]h  
} :e]9T3Q  
} O R<"LTCL  
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