http断点续传简单实现（java)

/* CkV5PU  
**SiteFileFetch.java J%u,qF}h  
*/ 'Qh1$X)R7a  
package NetFox; T-LX>*  
import java.io.*; kV+%(Gl8  
import java.net.*; )dd1B>ej]  
2 EWXr+IU.  
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public class SiteFileFetch extends Thread { Y}]-o9Rl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4{@{VsXN  
long[] nStartPos; //开始位置 BsU}HuQZQ  
long[] nEndPos; //结束位置 N;']&f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 njc-=o  
long nFileLength; //文件长度 RR+{uSO,t  
boolean bFirst = true; //是否第一次取文件 H$+@O-  
boolean bStop = false; //停止标志 <D[0mi0  
File tmpFile; //文件下载的临时信息 ]OtnekkK$  
DataOutputStream output; //输出到文件的输出流 ]"&](e6*  
4[(NxXH8M  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） I>GBnx L  
public SiteFileFetch(SiteInfoBean bean) throws IOException rz0)S py6  
{ en'"" w  
siteInfoBean = bean; wRvh/{xB  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =EYWiK77a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u"uL
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if(tmpFile.exists ()) [!De|,u(^  
{ 57~y
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bFirst = false; ZTibF'
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read_nPos(); D4b-Y[/"  
} f14^VTzP/#  
else RA!q)/+  
{ /5<=m:  
nStartPos = new long[bean.getNSplitter()]; P6&%`$  
nEndPos = new long[bean.getNSplitter()]; egvb#:zW?  
} R RE8|%p;B  
m"T}em#  
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} ?ac4GA(  
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public void run() Wqkzj^;"G  
{ Wqkb1~]#Y  
//获得文件长度 X$;&Mdo.  
//分割文件 |his8\C+x  
//实例FileSplitterFetch lLp,sNAj  
//启动FileSplitterFetch线程 :r@
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//等待子线程返回 `% QvCAR  
try{ 1~'jC8&J  
if(bFirst) xbBqR_H_  
{ cGiL9|k  
nFileLength = getFileSize(); *f3StX  
if(nFileLength == -1) +J|H~`  
{ pB4Uc<e  
System.err.println("File Length is not known!"); @)BO`;*$fF  
} WR3,woo  
else if(nFileLength == -2) `sCn4-$8  
{ ,sIC=V +  
System.err.println("File is not access!"); @AF<Xp{  
} V^,eW!  
else gfs;?vP  
{ zGFD71=#  
for(int i=0;i<nStartPos.length;i++) i84!x%|P  
{ <:V~_j6P0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tEL9hZzI  
} v
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for(int i=0;i<nEndPos.length-1;i++) w`;HwK$ ,  
{ fz\Q>u'T  
nEndPos = nStartPos[i+1]; UXlZI'|He  
} puJB&u"4L  
nEndPos[nEndPos.length-1] = nFileLength; >v%js!`f  
} J09jBQ]R  
} y?&hA!x  
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=KUmvV*\  
//启动子线程 a3>/B$pE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :{#O  
for(int i=0;i<nStartPos.length;i++) odSPl{.>d  
{ G0{Z@CvO'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T#H^ }`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !uQT4<g  
nStartPos,nEndPos,i); 4
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J\r\_P@;c  
fileSplitterFetch.start(); ejlns ~  
} +U2lwd!j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "~5cz0 H3v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N^dQX,j  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 54CJ6"q  
nEndPos = " + nFileLength); +bS\iw+  
// fileSplitterFetch[nPos.length-1].start(); V2ih/mh   
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//等待子线程结束 .P$m?p#  
//int count = 0; ]:Gy]qkO  
//是否结束while循环 )
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boolean breakWhile = false; %+H_V1F  
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while(!bStop) $G-<kC}8:  
{ KGYbPty}  
write_nPos(); ?1D!%jfi  
Utility.sleep(500); BS*79heY  
breakWhile = true; $ ]s^M=8  
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for(int i=0;i<nStartPos.length;i++) 7a1o#O  
{ ,7LfvZj4[  
if(!fileSplitterFetch.bDownOver) B;r_[^  
{ 3'Y-~^ml|  
breakWhile = false; ^Hv&{r77  
break;  px<psR5  
} Lw}-oE !U  
} T82 `-bZ  
if(breakWhile) :QGkYJ  
break; oFj_o  
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//count++; 1ysfpX{=  
//if(count>4) -Cs( 3[  
// siteStop(); nzC *mPX8  
} uQIPnd(V  
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System.err.println("文件下载结束！"); i%-yR DIX  
} Q>,&@  
catch(Exception e){e.printStackTrace ();} z2i
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} (oGYnN,2  
}PBme'kP  
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//获得文件长度 c!ZZMCs  
public long getFileSize() k( :Bl  
{ rLsY_7!  
int nFileLength = -1; E`o_R=%  
try{ /_0B5,6R  
URL url = new URL(siteInfoBean.getSSiteURL()); iT}>a30]B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R iLl\S#  
httpConnection.setRequestProperty("User-Agent","NetFox"); '#7k9\  
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int responseCode=httpConnection.getResponseCode(); ij$NTY=u  
if(responseCode>=400) I=kqkuW  
{ ZaYiby@Ci  
processErrorCode(responseCode); g8Ex$,\,  
return -2; //-2 represent access is error ,Z~`aHhr  
} !T,<p   
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String sHeader; F9 r5 Z  
] 0X|_bU  
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for(int i=1;;i++) Pvc)-A  
{ <D.E.^Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !-lI<$S:  
//Utility.log(in.readLine()); N;3!oo4  
sHeader=httpConnection.getHeaderFieldKey(i); z}[u~P,  
if(sHeader!=null)
<  o?ua}  
{ juR>4SH  
if(sHeader.equals("Content-Length")) @D;K&:~|N  
{ :qdyCsn2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !, BJO3&  
break; d_25]B(  
} 2nyK'k  
} G<?RH"RZr  
else peVY2\1>R  
break; p& _Z}Wv  
} JTKS5r7?  
} 05 6K)E  
catch(IOException e){e.printStackTrace ();} =`3r'c  
catch(Exception e){e.printStackTrace ();} l ms^|?  
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Utility.log(nFileLength); )Z:-qH  
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return nFileLength; {'{}@CuA2  
} mW"e  
}!iopu  
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//保存下载信息（文件指针位置） xRWfZ3E#  
private void write_nPos() B&_:20^y~  
{ \^(#b,k#  
try{ }rJqMZ]w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6|EOB~|  
output.writeInt(nStartPos.length); B
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for(int i=0;i<nStartPos.length;i++) -9om,U`t  
{ Tv|'6P  
// output.writeLong(nPos); MGF!Z
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output.writeLong(fileSplitterFetch.nStartPos); JPDxzp  
output.writeLong(fileSplitterFetch.nEndPos); a?y ucA  
} _/:--Z  
output.close(); WfO EI1  
} z -?\b^  
catch(IOException e){e.printStackTrace ();} ^VYR}
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catch(Exception e){e.printStackTrace ();} sccLP_#Z  
} .V!5Ui<  
|B(,53  
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//读取保存的下载信息（文件指针位置） Q,.dIPla  
private void read_nPos() @wXYza0|d  
{ =#2%[kGq  
try{ NN7KwVg
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); - k0a((?  
int nCount = input.readInt(); D\G 8p;  
nStartPos = new long[nCount]; |KJGM1]G  
nEndPos = new long[nCount]; r3Ol?p  
for(int i=0;i<nStartPos.length;i++) aUMiRm-  
{ cUug}/!I  
nStartPos = input.readLong(); !\'w>y7  
nEndPos = input.readLong(); y;ey(  
} c\.)vH  
input.close(); 4M"'B A<  
} Ue9d0#9  
catch(IOException e){e.printStackTrace ();} |}77'w :  
catch(Exception e){e.printStackTrace ();} g
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} bD v&;Z  
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private void processErrorCode(int nErrorCode)
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{ {%wrx'<  
System.err.println("Error Code : " + nErrorCode); |~76dxU  
} I_B%F#X)  
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//停止文件下载 /*g0M2+OZo  
public void siteStop() [ (Y@  
{ %Ok#~>c  
bStop = true; @w33u^  
for(int i=0;i<nStartPos.length;i++) 9uxoMjR-  
fileSplitterFetch.splitterStop(); c*owP  
 \&d1bq  
]#N8e?b,  
} ;-i)}<  
} ~I")-2"B  
//负责部分文件的抓取 GB+$ed5@<  
**FileSplitterFetch.java V~Guw[RA  
*/ Vb\^xdL>  
package NetFox; JSFNn]z2P  
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import java.io.*; m!INbIh  
import java.net.*; h9d*N9!;M  
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public class FileSplitterFetch extends Thread { A/zAB3  
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String sURL; //File URL >uJu!+#  
long nStartPos; //File Snippet Start Position UJS vtD{g  
long nEndPos; //File Snippet End Position F`;q9<NYRW  
int nThreadID; //Thread's ID WG3_(mM  
boolean bDownOver = false; //Downing is over [g==#[  
boolean bStop = false; //Stop identical .mnkV -m  
FileAccessI fileAccessI = null; //File Access interface 2kgSIvk\  
-4Q\FLC'k  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y;\@ 5TgQ,  
{ a{e1g93}  
this.sURL = sURL; ZkibfVwe  
this.nStartPos = nStart; p>U= Jg  
this.nEndPos = nEnd; ,jnaa(n  
nThreadID = id; V%*91t_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 r{*Qsaw  
} bz1`f>%l  
~- 
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public void run() uKY1AC__  
{ L{ej<0yr  
while(nStartPos < nEndPos && !bStop) IM,d6lN6s  
{ >z3l@  
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0#5
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try{ ZXj*Vu$_4  
URL url = new URL(sURL); h5vetci/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6R2F,b(_  
httpConnection.setRequestProperty("User-Agent","NetFox"); MO1H?Uhx  
String sProperty = "bytes="+nStartPos+"-"; =BD|uIR  
httpConnection.setRequestProperty("RANGE",sProperty); RP^L.X(7^  
Utility.log(sProperty); (Ms0pm-#t  
75h]#k9\  
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InputStream input = httpConnection.getInputStream(); TPj,
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//logResponseHead(httpConnection); 8XCT[X  
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byte[] b = new byte[1024]; ^]/
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int nRead; '8^cl:X  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) iYW<qgz  
{ `/G9*tIR8g  
nStartPos += fileAccessI.write(b,0,nRead); -lfbn=3  
//if(nThreadID == 1) {rF9[S"h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }_}LaEYAo  
} c?Zi/7  
DEPsud;  

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Utility.log("Thread " + nThreadID + " is over!"); N7q6pBA"E  
bDownOver = true; B90fUK2g  
//nPos = fileAccessI.write (b,0,nRead); {\h:k\k  
} &`'@}o>2  
catch(Exception e){e.printStackTrace ();} ?wIw$p>wT  
} bvl!^xO]  
} )|]*"yf:E  
nWd;XR6|  
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//打印回应的头信息 {H=<5  
public void logResponseHead(HttpURLConnection con) &j"_hFhv  
{ i\>?b)a>  
for(int i=1;;i++) ^= kr`5  
{ '~{kR=+  
String header=con.getHeaderFieldKey(i); 2/))Y\~  
if(header!=null) 4?_^7(%p  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); R<r,&X?m  
Utility.log(header+" : "+con.getHeaderField(header)); Fbw.Y6  
else 7?y([i\y  
break; fndH]Yp  
} +}g6X6m  
} Rx@0EPV  
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public void splitterStop() D4{<~/oBv  
{ I!Fd~g9I4  
bStop = true; Vc8w[oS  
} B;<zA' 1  
a 4?c~bs  
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s  
} ]~pM;6Pu0  
|/u,6`  
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/* Sq`Zu
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**FileAccess.java .;dI&0Z  
*//文件访问(定位，写) /i"1e:cK  
package NetFox; OP``+z>  
import java.io.*; WuQ;Da0+_F  
|QyZ:`0u  
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public class FileAccessI implements Serializable{ !H zJ*  
2\"T&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =Nz;R2{@  
RandomAccessFile oSavedFile; =s:Z-*vy!  
long nPos; V|2[>\Cv  
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public FileAccessI() throws IOException )SaMfP1=v  
{ =|V#~p*  
this("",0); Om8Sgy?  
} Rz<'&Z>;  
"!#KQ''R  
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public FileAccessI(String sName,long nPos) throws IOException q^}iXE~  
{ G,b*Qn5#  
oSavedFile = new RandomAccessFile(sName,"rw"); cj|Urt  
this.nPos = nPos; EiPOY'  
oSavedFile.seek(nPos); C jz(-018  
} nKch:g  

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}(#;{_  
public synchronized int write(byte[] b,int nStart,int nLen) /9ZU_y4&3f  
{ ,/eAns`ZU  
int n = -1; cZ,}1?!  
try{ Cv< s|  
oSavedFile.write(b,nStart,nLen); e'3y^Vg  
n = nLen; K{iC'^wP  
} %\1W0%w  
catch(IOException e) O~5*X f  
{ ,UxAHCR~9  
e.printStackTrace (); *3(mNpi{_  
} T?*f}J  
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qKI)*o062  
return n; vSo,,~F  
} 
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} /kqa|=-`q  
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/* eY
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**SiteInfoBean.java Hw,@oOh.  
*/ l-8rCaq&J  
package NetFox; 
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-=2V4WU~  
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public class SiteInfoBean { +DYsBCVbag  
8)YDUE%VH  
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private String sSiteURL; //Site's URL iE^=Vf;  
private String sFilePath; //Saved File's Path O0sLcuT$  
private String sFileName; //Saved File's Name vSwRj<|CF  
private int nSplitter; //Count of Splited Downloading File ;IR.6k$;  
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rb]?"lizi  
public SiteInfoBean() |}o3EX  
{//nSplitter的缺省值为5 /PEL[
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//default value of nSplitter is 5 :CP,DO
 
this("","","",5); ka*#O"}L8  
} FlT5R*m  
WIw*//nw  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;eW\41w  
{ 5i=C?W`'  
sSiteURL= sURL; 5a5)hmO RB  
sFilePath = sPath; T1(*dVU?  
sFileName = sName; kTm}VTr 1  
this.nSplitter = nSpiltter; C~04#z_$  
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} [=^Wj`;  
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public String getSSiteURL() U,Fyi6{~  
{ rXq{WS`  
return sSiteURL; U.N?cKv  
} 0CK3jdZ+X  
/z: mi  
=G`g-E2  
public void setSSiteURL(String value) dEZlJo@J  
{ XmN8S_M>v  
sSiteURL = value; ;KT5qiqYH  
} &W{v(@  
~,.;2K73  
#g<6ISuf  
public String getSFilePath() k&17 (Tv$  
{ P[tYu:  
return sFilePath; TrBW0Bn>p  
} U|x#'jGo'  
H^M>(kT#&  
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public void setSFilePath(String value) mB"1QtD  
{ 1o?uf,H7O  
sFilePath = value; 
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} >+):eBL  
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public String getSFileName() 5t-,5  
{ S:1g(f*85  
return sFileName; ,(NN)Oj  
} h=B= J  
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public void setSFileName(String value) aP#/%  
{ Q"H/RMo-  
sFileName = value; L2OR<3*|Av  
} z, n[}Q#u  
hw=~%f;  
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public int getNSplitter() *q+X?3  
{ d{Owz&PL  
return nSplitter; A#Y:VavQ?  
} OsKtxtLO  
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public void setNSplitter(int nCount) `@#rAW D  
{ b7B|$T,  
nSplitter = nCount; nlA
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} ',/2J0_  
} Y(R.<LtY  
$=) Pky-~  
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/* nu(7YYCM$  
**Utility.java o=Y'ns^a(  
*/ ]J@-,FFC  
package NetFox; D"%>  
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public class Utility { z"Mk(d@-E  
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public Utility() Q!_d6-*u  
{ (>NZYPw^3  
aemi;61T\  
+}PN+:yV  
} Je}0KW3G9L  
+wxsAGy_j  
//线程睡眠 c94=>p6  
public static void sleep(int nSecond) p}<60O"r$  
{ o4wSt6gBcJ  
try{ jcb&h@T8kv  
Thread.sleep(nSecond); |gIE$rt-~W  
} fH$#vRcq  
catch(Exception e) mhy='AQJ  
{ _ j`tR:  
e.printStackTrace (); SZ}=~yoD(  
} k81%$E  
} 5DVYHN9c|  
V@[C=K
  
//日志 {Wu[e,p  
public static void log(String sMsg) n4y]h  
{ fP\q?X@]E  
System.err.println(sMsg); 8KYIHw  
} )]s<Czm%  
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public static void log(int sMsg) [:cvy[}v@  
{ =E<H_cUS  
System.err.println(sMsg); }pIn3B)  
} D <R_eK  
} 9\c]I0)3p  
2`TV(U@  
M:b#">M  
/* =4l @A>  
**TestMethod.java )BvMFwQG  
*/ Hf\sF(, (  
package NetFox; kguZAO6  
+@
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public class TestMethod { Fj]06~u  
q=Vh"]0g  
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public TestMethod() =*"8N-FU  
{ ///xx/weblogic60b2_win.exe ]Yw$A  
try{ ~UZ3 lN\E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &*%x]fQ@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); tW/g0lC%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8|)^m[c&  
fileFetch.start(); @XXPJq;J  
} WgqSw%:$H  
catch(Exception e){e.printStackTrace ();} m\X\Xp~A  
J=k=cFUX  
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} x7U=1y(  
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public static void main(String[] args) tH44\~  
{ >6HGh#0(p  
new TestMethod(); ;RRw-|/Wm  
} 
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} zX4RqI  
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