http断点续传简单实现（java)

/* hvwr!(|W  
**SiteFileFetch.java 0!T $Ef  
*/ %\u>%s
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package NetFox; x4(WvQ%O#  
import java.io.*; *%.*vPJ  
import java.net.*; v,! u{QP  
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public class SiteFileFetch extends Thread { {WChD&v  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %$U+?lk}  
long[] nStartPos; //开始位置 ] N8V?.|:  
long[] nEndPos; //结束位置 >ZT3gp?E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 uFgw eOJ  
long nFileLength; //文件长度 d
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boolean bFirst = true; //是否第一次取文件 8^~]Ym:  
boolean bStop = false; //停止标志 Cq=c'(cX  
File tmpFile; //文件下载的临时信息 Yi3DoaS;"  
DataOutputStream output; //输出到文件的输出流 ^[6AOz+L  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4?cg6WJ'6  
public SiteFileFetch(SiteInfoBean bean) throws IOException f sMF46  
{ u
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siteInfoBean = bean; !{+(oDN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -ydT%x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u=5^xpI<D
 
if(tmpFile.exists ()) k
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{ P]G2gDO  
bFirst = false; lnhZ!_  
read_nPos(); S!uyplYKF  
} ]`x~v4JU  
else _XN sDW4|  
{ E;SFf  
nStartPos = new long[bean.getNSplitter()]; _[V 6s#Wk3  
nEndPos = new long[bean.getNSplitter()];  zcc]5>  
} qohUxtnTK>  
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} p("do1:  
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public void run() .nnA
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{ EJZ2V>\_-0  
//获得文件长度 Ec|#i  
//分割文件 on~rrSK  
//实例FileSplitterFetch gBN;j  
//启动FileSplitterFetch线程 UCFef,VW  
//等待子线程返回 fu/v1~X  
try{ 2
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if(bFirst) pq4frq  
{ :(Gg]Z9^8  
nFileLength = getFileSize(); Xv6s,<#\  
if(nFileLength == -1) 2KU[Yd  
{ nX~sVG{Q  
System.err.println("File Length is not known!"); g]S.u8K8m  
} DY%E&Vd:h  
else if(nFileLength == -2) '<O& :  
{ -7u4f y{T  
System.err.println("File is not access!"); -Rmz`yOq}  
} ~*RNJ  
else h c"n?  
{ +g*Ko@]m>  
for(int i=0;i<nStartPos.length;i++) ey:3F%  
{ e(b*
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); VrHFM(RNe  
} y3lsAe#  
for(int i=0;i<nEndPos.length-1;i++) 6D>o(b2  
{ ~<aCn-h0  
nEndPos = nStartPos[i+1]; a`}HFHm\2,  
} :)&_
 
nEndPos[nEndPos.length-1] = nFileLength; >R6Me*VR  
} E/ Pa0.  
} {?82>q5F  
|zSkQ_?54  

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//启动子线程 V`G]4}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D(y=0),  
for(int i=0;i<nStartPos.length;i++) [/I4Pe1Yj%  
{ 6HyQm?c>a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N=(rl#<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3K{'~?mM  
nStartPos,nEndPos,i); Bb m1&d#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >n#Pq{7aF  
fileSplitterFetch.start(); hD"Tjd` P  
} 1 #_R`(C{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y'{0|Xj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6j0!$q^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8[eH8m#~$  
nEndPos = " + nFileLength); P66>w})@  
// fileSplitterFetch[nPos.length-1].start(); (sZB-  
1^vN?#Kt  
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//等待子线程结束 hW]:CIqk  
//int count = 0; 7 'N&jI   
//是否结束while循环 rTQrlQ:@  
boolean breakWhile = false; 94Are<  
U:p<pTnMR  
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while(!bStop) Y~,N,>nITu  
{ hl8[A-d(R  
write_nPos(); zUWu5JI  
Utility.sleep(500); 8|gwH2st~  
breakWhile = true; -(P"+g3T  
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for(int i=0;i<nStartPos.length;i++) gWRSS=8%  
{ GC.   
if(!fileSplitterFetch.bDownOver) 2!}5shB  
{ |GLa`2q|  
breakWhile = false; &W*9'vSm.  
break; 7a
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} X180_Kt2  
} ^2=11  
if(breakWhile) .z+[3Oj_E  
break; @#;2P'KL  
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*1|&uE&_R  
//count++; ~'n3],o?  
//if(count>4) f/aSqhAW  
// siteStop(); J'W6NitMr  
} ?!KqDI  
4vF1  
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System.err.println("文件下载结束！"); rz5AIe>Hm  
} Cjdw@v0;  
catch(Exception e){e.printStackTrace ();} 7xqTT
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} a%cCR=s=  
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//获得文件长度 um~U_&>  
public long getFileSize() T|[zk.8=E  
{ <7-3j{065  
int nFileLength = -1; 4vC { G.  
try{ gy0l@ 5 N  
URL url = new URL(siteInfoBean.getSSiteURL()); [BWA$5D)Ny  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &c%;Lo  
httpConnection.setRequestProperty("User-Agent","NetFox"); Dm2&}{&K  
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int responseCode=httpConnection.getResponseCode(); qX>mOW^gT8  
if(responseCode>=400) !/2uO5  
{ d?)k<!fJk  
processErrorCode(responseCode); M|xd9kA^  
return -2; //-2 represent access is error <'f+nC=2  
} UU~S{!*+L  
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String sHeader; =f4>vo}@k  
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for(int i=1;;i++) DvhJkdLB>  
{ Pv@Lx+k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1ayL*
tr  
//Utility.log(in.readLine()); >UlAae44  
sHeader=httpConnection.getHeaderFieldKey(i); $}+t|`*q8]  
if(sHeader!=null)  UDl[  
{ ,ELbm  
if(sHeader.equals("Content-Length")) _P,3~ ;  
{ xA/Ein0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); AUBZ7*VO  
break; j S~Wcu  
} }&!fT\4  
}
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else GI']&{  
break; v"-@'qN'  
} <a_ytSoG1  
} I54`}Npp  
catch(IOException e){e.printStackTrace ();} 4Cm+xAXG  
catch(Exception e){e.printStackTrace ();} Vh=10Et  
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Utility.log(nFileLength); $IUe](a{d  
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return nFileLength; d^pzMaCI  
} d>k)aIYp  
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//保存下载信息（文件指针位置） o>~xrV`E  
private void write_nPos() PLoD^3uG)  
{ ]fiAV|'^  
try{ jxeZ,w o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); dK.k,7R  
output.writeInt(nStartPos.length); M4rI]^lJ  
for(int i=0;i<nStartPos.length;i++) B\*"rSP\  
{ ebv"`0K$  
// output.writeLong(nPos); KF!?;q0J  
output.writeLong(fileSplitterFetch.nStartPos); *UxN~?
N|  
output.writeLong(fileSplitterFetch.nEndPos); E)ne z  
} N./l\NtZ  
output.close(); QTe>EJ12  
} 3IB||oN$T  
catch(IOException e){e.printStackTrace ();} !N"Y  
catch(Exception e){e.printStackTrace ();} C[c^zn  
} 8>4@g!9E  
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//读取保存的下载信息（文件指针位置） cI#! Y  
private void read_nPos() %0&c0vT  
{ KdN+$fe*g  
try{ v2K6y|6,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); k z{_H`5.  
int nCount = input.readInt(); MeCHn2zwB  
nStartPos = new long[nCount]; 3+~m9:9  
nEndPos = new long[nCount]; U]Pl` =SL  
for(int i=0;i<nStartPos.length;i++) `%@|sK2  
{ SobOUly5{  
nStartPos = input.readLong(); ;;f&aujSHD  
nEndPos = input.readLong(); n.L/Xp@gc  
} @T 5dPmn  
input.close(); HdR%
n  
} /
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catch(IOException e){e.printStackTrace ();} yUY* l@v]  
catch(Exception e){e.printStackTrace ();} w%'8bH!  
} K (px-jY  
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private void processErrorCode(int nErrorCode) I l2`c}9  
{ ~Y)h[  
System.err.println("Error Code : " + nErrorCode); RvXK?mL4F  
} :n0czO6E  

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//停止文件下载 MdKkj[#  
public void siteStop() ~[[(_C3  
{ mu$0x)  
bStop = true; =]F;{x  
for(int i=0;i<nStartPos.length;i++) 1^v?Ly8  
fileSplitterFetch.splitterStop(); <<vT"2Q]  
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} P&$ m2^K  
} _]aA58,j  
//负责部分文件的抓取 AhA4IOG`.  
**FileSplitterFetch.java .).}ffhOL  
*/
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package NetFox; [Z-S0  
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import java.io.*; q{RH/. l  
import java.net.*; nm}wdel"  
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public class FileSplitterFetch extends Thread { g#}a?kTM@  
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String sURL; //File URL =}pPr]Cc  
long nStartPos; //File Snippet Start Position ;)7GdR^K  
long nEndPos; //File Snippet End Position ~tM+!  
int nThreadID; //Thread's ID UB8TrYra  
boolean bDownOver = false; //Downing is over LkK# =v  
boolean bStop = false; //Stop identical ;}W-9=81  
FileAccessI fileAccessI = null; //File Access interface a9%^Jvm"  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException m,|)$R  
{ 0x1#^dII  
this.sURL = sURL; \ )'`F; P  
this.nStartPos = nStart; FBk_LEcX  
this.nEndPos = nEnd; ]>_Ie?L)<  
nThreadID = id; v<u`wnt  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |,)=-21&;  
} lO+6|oF0  
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public void run() I[g;p8jr  
{ ,z@"pI b  
while(nStartPos < nEndPos && !bStop) 9vL n#_  
{ z]d2 rzV(_  
Nk ~"f5q7  
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try{ 6jaol'{SuH  
URL url = new URL(sURL); j~;kh_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bd& /B&a  
httpConnection.setRequestProperty("User-Agent","NetFox"); h
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String sProperty = "bytes="+nStartPos+"-"; [OU[i(,{  
httpConnection.setRequestProperty("RANGE",sProperty); yE{(Ebm  
Utility.log(sProperty); %V;B{?>9zB  
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InputStream input = httpConnection.getInputStream(); +#@)C?G,TF  
//logResponseHead(httpConnection); @b@# o  
(fUpj^E)p  
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byte[] b = new byte[1024]; _Yqog/sG  
int nRead; SSH 1Ge5|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @4FG& >kQ  
{ Ro:DAxi@L  
nStartPos += fileAccessI.write(b,0,nRead); ]Te,m}E  
//if(nThreadID == 1) xa&5o`>1G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PN"s^]4  
} -#agWqUM|T  
]ML(=7z"  
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Utility.log("Thread " + nThreadID + " is over!"); IMT]!j&Y,  
bDownOver = true; |08'd5  
//nPos = fileAccessI.write (b,0,nRead); JIH6!  
} O*dtVX  
catch(Exception e){e.printStackTrace ();} @SX-=Nr  
} ='z4bU  
} Yb?L:,a(I  
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Op>l~{{{  
//打印回应的头信息 +>*! 3x+sE  
public void logResponseHead(HttpURLConnection con) :41Ch^\E  
{ +`]AutNv  
for(int i=1;;i++) #*|Gp_l+%  
{ +5xVgIk#  
String header=con.getHeaderFieldKey(i); 2}<_l 2  
if(header!=null) +B#+'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o-7,P RmKN  
Utility.log(header+" : "+con.getHeaderField(header)); \YMe&[C:o  
else _GF{Duxh  
break; +ebmve \+  
} appWq}db  
} ^0T DaZDLp  
tsf)+`vt  
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public void splitterStop() gi#g)9HG  
{ !Sj
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bStop = true; k[<Uxh%  
} @q/E)M?  
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} ]mZN18#  
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/* 7^<{aE:  
**FileAccess.java Nay&cOz  
*//文件访问(定位，写) S:YQVj  
package NetFox; XFmTr@\M  
import java.io.*; 40$- ]i  
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public class FileAccessI implements Serializable{ H
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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 Uw5AHq).  
RandomAccessFile oSavedFile; K}a3Bj,  
long nPos; (@nEe?  
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public FileAccessI() throws IOException Z#
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{ T6^H%;G  
this("",0); "fN=Y$G  
} qS?uMms7w  
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public FileAccessI(String sName,long nPos) throws IOException J<h!H  
{ /c|X:F!;X#  
oSavedFile = new RandomAccessFile(sName,"rw"); I:=rwnd  
this.nPos = nPos; 5!jU i9  
oSavedFile.seek(nPos); 3Q:HzqG  
} O;8
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!HCuae3_  
=tQ^t4_  
public synchronized int write(byte[] b,int nStart,int nLen) zbgH}6b  
{ ({!S!k  
int n = -1; 1G`zwfmh~  
try{ YDWV=/  
oSavedFile.write(b,nStart,nLen); `x:8m?q05  
n = nLen; Z(wj5;[G  
} HF;$Wf+=J  
catch(IOException e) MfG8=H2#|  
{ PW QRy  
e.printStackTrace (); ["N_t:9I  
} 6z2WN|78  
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return n; h,@tfd U^  
} 5lrjM^E|  
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} p:?h)'bA<  
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`NB6Of*/  
/* w0&|8y  
**SiteInfoBean.java Y{D?
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*/ =x3T+)qCNX  
package NetFox; %}[/lIxaE  
# ~(lY}  
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public class SiteInfoBean { TW~%1G_v  
/H~]5JZ3-E  
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private String sSiteURL; //Site's URL 2e^6Od!Y?  
private String sFilePath; //Saved File's Path 0@
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private String sFileName; //Saved File's Name JsK_q9]$e  
private int nSplitter; //Count of Splited Downloading File Ev]oPCeA  
:3A^5}iz  
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public SiteInfoBean() moCr4*jDX,  
{//nSplitter的缺省值为5 6(8zt"E  
//default value of nSplitter is 5 ZO8r8 [  
this("","","",5); 'BX U'  
} iT=h}>  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $Y?[[>u  
{ -58Sb"f  
sSiteURL= sURL; 1qm _Qs&  
sFilePath = sPath; {xu~Dx  
sFileName = sName; IylfMwLC  
this.nSplitter = nSpiltter; #ja6nt8GC  
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s)~Wcp'+M:  
} @B9O*x+n:  
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public String getSSiteURL() mt\pndTy7!  
{ fRK=y+gl@  
return sSiteURL; Rc(E';uc  
} 7;@o]9W  
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public void setSSiteURL(String value) [13NhF3.P  
{ D:0?u_[W  
sSiteURL = value; +ux170Cd3  
} 1 &-%<o  
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public String getSFilePath() q'KXn0IY#  
{ ,% *Jm
  
return sFilePath; I/_,24[  
} F0KNkL>&g  
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2\  
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public void setSFilePath(String value) 1xjw=  
{ 48LzI@H&  
sFilePath = value; u85?f  
} f"Kl?IN8  
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public String getSFileName() jygKw+C  
{ H+npe'm_Z  
return sFileName; 8I<LZ{a10  
} `P jS  
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public void setSFileName(String value) Xu& v3Y~k  
{ \me-#: Gu  
sFileName = value; =~q Xzq  
} UQn
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d(F4-kBd  
public int getNSplitter() tUhr gc  
{ G5*_  
return nSplitter; xM13OoU  
} 8X)1bNGqhe  
,lQfsntk'  
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public void setNSplitter(int nCount) zTg&W7oz  
{ J=B,$4)9  
nSplitter = nCount; nmoC(| r  
} Y0g6zHk7  
} $: qrh6
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I 8 Ls_$[  
/*
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**Utility.java G$1gk^G's  
*/ VL2ACv(  
package NetFox; =|qYaXjT$  
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public class Utility { N[wyi&m4  
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public Utility() Rip[  
{ _F3= H]P  
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Y 016Xg5  
} 1G 63eH)!  
%$=}ePD  
//线程睡眠 m-'+)lB  
public static void sleep(int nSecond) 02q*z>:^  
{ 3`{[T17  
try{ cLm{gd4 W  
Thread.sleep(nSecond); 0b+End#mp  
} ;c|G  
catch(Exception e) 4n/CSAT1  
{ 8[d6 s  
e.printStackTrace (); q@}tv=}  
} GtkZ%<KF9  
} ^A$p)`KR  
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//日志 s`o_ER  
public static void log(String sMsg) =:Lc-y>  
{ 6Lz:J:Q)  
System.err.println(sMsg); B^BbA-I  
} &u0on)E  
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g/O
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public static void log(int sMsg) * NdL4c~  
{ yYvv!w+@Q  
System.err.println(sMsg); PZhpp"  
} 7r$'2">K(  
}
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/* v v]rXJu1  
**TestMethod.java V,>uM >$  
*/ ,{g B$8z^  
package NetFox; ;(;{~1~  
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public class TestMethod { ~jM!8]=  
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public TestMethod() U[c
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{ ///xx/weblogic60b2_win.exe sU;aA0kz  
try{ qm|T<zsDY#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pR7D3Q:^7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); CO"Nv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kqp*o+Oz',  
fileFetch.start(); t"FB}%G  
} 6F08$,%Y  
catch(Exception e){e.printStackTrace ();}  bj U]]  
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} +{@hD+  
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#B8V2_M
 
public static void main(String[] args) 6"_ytqw7  
{ #H&`wMZZ:  
new TestMethod(); j4!oBSp  
} k{.`=j  
} b[ .pD3  
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