http断点续传简单实现（java)

/* vp9<.*h  
**SiteFileFetch.java [k}\{i>  
*/ sZDJ+  
package NetFox; *?"{T;4u~O  
import java.io.*; X($SBUS6  
import java.net.*; Y\|J1I,Z4  
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public class SiteFileFetch extends Thread { 9v2 ;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean c/U6K yiK  
long[] nStartPos; //开始位置 EQ$9IaY.  
long[] nEndPos; //结束位置 Lc?O K"[m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <J`xCm K  
long nFileLength; //文件长度 d vxEXy  
boolean bFirst = true; //是否第一次取文件 jsQ$.)nO  
boolean bStop = false; //停止标志 9-6_:N>
 
File tmpFile; //文件下载的临时信息 8E[`H  
DataOutputStream output; //输出到文件的输出流 b\S}?{m5  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ! fc)  
public SiteFileFetch(SiteInfoBean bean) throws IOException N Z`hy>LF^  
{ ,+9r/}K]/  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^W'[l al.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p]eD@3Wz  
if(tmpFile.exists ()) >6+K"J-@  
{ efR$s{n!  
bFirst = false; ,ua1xsZl&  
read_nPos(); V}-o):dI|  
} mO.U)tL[  
else 1}*;  
{ zmRK%a(  
nStartPos = new long[bean.getNSplitter()]; J3;KQ}F.I  
nEndPos = new long[bean.getNSplitter()]; xltu g##  
} pa-4|)qY  
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} AAgA]OD,  
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public void run() 2Zip8f!  
{ 'qE  
//获得文件长度 F-0PmO~3+W  
//分割文件 Hc|U@G  
//实例FileSplitterFetch )A=g# D#  
//启动FileSplitterFetch线程 eCD,[At/  
//等待子线程返回 MGDv4cFE.  
try{ BxYA[#fd}  
if(bFirst) ]i2\2MTW8  
{ :PkZ(WZ9  
nFileLength = getFileSize(); !H\GHA'DO]  
if(nFileLength == -1) Dj(7'jT  
{ zAJ
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System.err.println("File Length is not known!"); HYmXPpse  
} ,>v9 Y#U  
else if(nFileLength == -2) [)vwg`]  
{ C/VYu-p%  
System.err.println("File is not access!"); Q@VnJ,  
} UROi.976D  
else MiM=fIuw@s  
{ |/s2AzDD  
for(int i=0;i<nStartPos.length;i++) 2tm-:CPG  
{ LfXr(2u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |9Ks13?Ck  
} 5>Yd\(`K  
for(int i=0;i<nEndPos.length-1;i++) /+O8A}  
{ q|l|mO  
nEndPos = nStartPos[i+1]; ?^4sE-C6  
} PGl-2Cr  
nEndPos[nEndPos.length-1] = nFileLength; 6
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} =2)t1 H  
} ^T6!z^g1h  
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//启动子线程 rss.F3dK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /C2f;h(1  
for(int i=0;i<nStartPos.length;i++) Ab<Ok\e5  
{ r;8z"*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,!u@
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), v/.h%6n?  
nStartPos,nEndPos,i); .ASwX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]Ja8i%LjOG  
fileSplitterFetch.start(); A=
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} UZXcKl>u  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ruA+1-<f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <;E[)tv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _D,f4.R  
nEndPos = " + nFileLength); kDl4t]j  
// fileSplitterFetch[nPos.length-1].start(); _s-HlE?C  
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//等待子线程结束 'Mx K}9  
//int count = 0; BRXb<M^;_  
//是否结束while循环 j*~dFGl)  
boolean breakWhile = false; ^@*zH?Rx{  
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8w8I:*  
while(!bStop) Hu(flc+z"  
{ K[>@'P}y  
write_nPos(); 0ij~
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Utility.sleep(500); _Z66[T+M  
breakWhile = true; Zjic"E1  
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for(int i=0;i<nStartPos.length;i++) >yA,@%X  
{ oD#<?h)(  
if(!fileSplitterFetch.bDownOver) L+~YCat|$U  
{ 1'v!9  
breakWhile = false; <\d|=>;  
break; *iRm`)zC(  
} XL7;^AE^Wl  
} teOBsFy/I  
if(breakWhile) H MjeGO.i  
break; q 5v?`c  
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<{NYD.  
//count++; FSU%?PxO  
//if(count>4) U.hERe~X  
// siteStop(); L;--d`[  
} #mRFUA  
^?s~Fk_V  
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System.err.println("文件下载结束！"); lsB9;I^+x  
} dm,}Nbc91(  
catch(Exception e){e.printStackTrace ();} 5rfH;`  
} O@r.>  
 z _O,Y  
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//获得文件长度 =CjNtD2]  
public long getFileSize() bCA2ik  
{ b'7z DZI]  
int nFileLength = -1; 5PGlR!^  
try{ <}EV*`w4  
URL url = new URL(siteInfoBean.getSSiteURL()); ~MhgAC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wc7mJxJxA  
httpConnection.setRequestProperty("User-Agent","NetFox"); qY$*#*Q
  
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int responseCode=httpConnection.getResponseCode(); #+K
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if(responseCode>=400) =% q?Cr  
{ $hjP}- oUX  
processErrorCode(responseCode); VqK%^  
return -2; //-2 represent access is error ]6t]m2~\  
} M5GY>3P$c  
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9Z,*h-o  
String sHeader; +Lm3vj_N  
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for(int i=1;;i++) 8K\'Z  
{ ;wij}y-6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); .i{>Z  
sHeader=httpConnection.getHeaderFieldKey(i); FI
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if(sHeader!=null) }>MP{67Dm  
{ _:35d1[  
if(sHeader.equals("Content-Length")) u0m5JD0/  
{ ]2Sfkl0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,CJAzGBS  
break; ([:]T$0 #  
} zRwb"  
} Lw*;tL<,  
else WnD^F>  
break; 01U *_\  
} _&8O~8tW  
} iO!27y  
catch(IOException e){e.printStackTrace ();} 5Z/yhF.{  
catch(Exception e){e.printStackTrace ();} G1]"s@8(  
q=|R
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Utility.log(nFileLength); 81~Kpx  
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return nFileLength; 1hl
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} >; aCf#q  
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//保存下载信息（文件指针位置） ac9q
j  
private void write_nPos() l0I}&,+  
{ 6yY.!HRkr  
try{ )h#]iGVN}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vu=me?m?(  
output.writeInt(nStartPos.length); ).LTts7c  
for(int i=0;i<nStartPos.length;i++) KkEv#2n  
{ {9L5Q  
// output.writeLong(nPos); -;^;2#](g  
output.writeLong(fileSplitterFetch.nStartPos); #kyl?E  
output.writeLong(fileSplitterFetch.nEndPos); %m9CdWb=w  
} 2K;#Evn'j  
output.close(); |'tW=  
} Guh%eR'Wt  
catch(IOException e){e.printStackTrace ();} cB#nsu>  
catch(Exception e){e.printStackTrace ();} 9qK
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} ({4]  
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//读取保存的下载信息（文件指针位置） P"1 S$oc  
private void read_nPos() UfO7+_2  
{ ,vV]"f  
try{ b
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2edBQYWd  
int nCount = input.readInt(); ZsZcQj6G,  
nStartPos = new long[nCount]; $<|ocUC7  
nEndPos = new long[nCount]; z>;$im  
for(int i=0;i<nStartPos.length;i++) 9AHSs,.t  
{ -I":Z2.fR  
nStartPos = input.readLong(); C)Jn[/BD  
nEndPos = input.readLong(); =oX>Ph+ P  
} DdSSd@,x*  
input.close(); Gs dnf 7  
} '7*=`q{  
catch(IOException e){e.printStackTrace ();} e'2Y1h  
catch(Exception e){e.printStackTrace ();} F2 ~%zNe  
} p_{("zQ  
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private void processErrorCode(int nErrorCode) cu&,J#r%  
{ ]X
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System.err.println("Error Code : " + nErrorCode); 6_gnEve h  
} PWB(5 f?  
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Q7gY3flg  
//停止文件下载 FJNF%a)x2I  
public void siteStop() J:j<"uPm  
{ jN0k9O>  
bStop = true; ceT&Y{T  
for(int i=0;i<nStartPos.length;i++) `zpbnxOL$T  
fileSplitterFetch.splitterStop(); uj|BQ`k  
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} k(%QIJH  
} Thr*^0$C  
//负责部分文件的抓取 xJZ@DR,#  
**FileSplitterFetch.java %ZP+zhn}  
*/ v4Ga0]VN$8  
package NetFox; Bi3+)k>u7  
bEV<iZDq%  
^pnG0(9  
import java.io.*; ]@^coj[  
import java.net.*; w}R~C  
%\$;(#h  
up'  
public class FileSplitterFetch extends Thread { LjB;;&VCn  
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String sURL; //File URL `Y=WMNy  
long nStartPos; //File Snippet Start Position 6 sxffJt  
long nEndPos; //File Snippet End Position f:B>zp;N  
int nThreadID; //Thread's ID Q7X3X,  
boolean bDownOver = false; //Downing is over K+=+?~  
boolean bStop = false; //Stop identical qFQ8  
FileAccessI fileAccessI = null; //File Access interface \dQx+f&t  
6x)$Dl  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9`//^8G:=  
{ :!a2]-D}  
this.sURL = sURL; Mb1t:Xf^g  
this.nStartPos = nStart; R"MRnr_4K  
this.nEndPos = nEnd; ^u}L;`L  
nThreadID = id; 
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 SUKxkc(  
} ml|W~-6l  
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public void run() mI*[>#q>  
{ <GHYt#GIZ+  
while(nStartPos < nEndPos && !bStop) +Q=1AXe  
{ Z+j\a5d?,  
R" )bDy?  
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try{ /&F,
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URL url = new URL(sURL); N,2s?Y_!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ")O`mXg-  
httpConnection.setRequestProperty("User-Agent","NetFox"); #_Z$2L"U  
String sProperty = "bytes="+nStartPos+"-"; 'TH15r@  
httpConnection.setRequestProperty("RANGE",sProperty); 
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Utility.log(sProperty); P0H6mn*  
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InputStream input = httpConnection.getInputStream(); 2aJ
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//logResponseHead(httpConnection); [V'QrcCF  
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byte[] b = new byte[1024]; pwwH<0[  
int nRead; k+
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "&+"@<  
{ Mu'8;9_6  
nStartPos += fileAccessI.write(b,0,nRead); !T]
(Udf  
//if(nThreadID == 1) |#6QThK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fDG0BNLY  
} 5_XV%-wM  
kJWN.  
k} ]T;|h]  
Utility.log("Thread " + nThreadID + " is over!"); WTImRXK4  
bDownOver = true; cUTE$/#s  
//nPos = fileAccessI.write (b,0,nRead); |t; ~:
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} L\y;LSTU  
catch(Exception e){e.printStackTrace ();} /mp*>sNr6  
} }%Bl>M
  
} [<'-yQ{l\  
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r5!/[_l  
//打印回应的头信息 @6l%,N<fou  
public void logResponseHead(HttpURLConnection con) JK.ZdY%  
{ wdUBg*X8  
for(int i=1;;i++) n_3O-X(  
{ hKzSgYxP=t  
String header=con.getHeaderFieldKey(i); *N{emwIq  
if(header!=null) :1Q!$  m  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6252N]*  
Utility.log(header+" : "+con.getHeaderField(header)); 3e(ehLc4DJ  
else s}N#n(  
break; 5uxBK"q  
} i;!H!-sM  
} EvOJ~'2 Y%  
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public void splitterStop() B" 3dQwQ  
{ 2(/g}  
bStop = true; cI=(\pC  
} }#X8@  
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} !"eIV@7  
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/* gdkwWoN.  
**FileAccess.java =+AS/Jq  
*//文件访问(定位，写) RIIitgV_  
package NetFox; \?jeWyo  
import java.io.*; 8>7&E-  
PG,_^QGCX  
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public class FileAccessI implements Serializable{ lGVEpCS}  
e@IA20  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6H'HxB4  
RandomAccessFile oSavedFile; HeG)/W?r  
long nPos; `\+@Fwfx  
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public FileAccessI() throws IOException Q9Q|lO  
{ e#E2>Bj;  
this("",0); i F+vl]  
} 7PkJ-JBA  
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public FileAccessI(String sName,long nPos) throws IOException 3"P }n  
{ ?yj6CL(,  
oSavedFile = new RandomAccessFile(sName,"rw"); lIProF0  
this.nPos = nPos; f-%NaTI  
oSavedFile.seek(nPos); L@gWzC~?Q  
} q=#} yEG  
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public synchronized int write(byte[] b,int nStart,int nLen) R%'^gFk8  
{ |<GDUwC_;  
int n = -1; \.3D~2cU  
try{ yfm^?G|sW  
oSavedFile.write(b,nStart,nLen); ~}+Hgi  
n = nLen; >hr{JJe  
} 3.qTLga|}  
catch(IOException e) 4!LCR}K  
{ kP?KXT3y  
e.printStackTrace (); =X.9,$Y  
} <^lRUw  
}5(Ho$S(  
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return n; /IM#.v  
} M-giR:,  
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} )lZp9O  
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/* r}jGUe}d  
**SiteInfoBean.java o!!yd8~*r  
*/ afb+GA!  
package NetFox; ZAXN6h  
)-`;1ca)s  
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public class SiteInfoBean { th&[Nt7  
cwL1/DGDB  
 z~>pVs
  
private String sSiteURL; //Site's URL =%>oR  
private String sFilePath; //Saved File's Path aM$W*-Y  
private String sFileName; //Saved File's Name ~mR'Q-hi<  
private int nSplitter; //Count of Splited Downloading File YR;^hs?  
|H!9fZO  
Z"
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public SiteInfoBean() -P]sRl3O;  
{//nSplitter的缺省值为5 b&5lYp"d  
//default value of nSplitter is 5 V@\%)J'g  
this("","","",5); ?2g`8[">  
} ,-OCc!7K  
J:kmqk!  
 &CG*)bE  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xSBc-u#< G  
{ -^ C=]Medl  
sSiteURL= sURL; '`Wwt.
A  
sFilePath = sPath; gB4U*D0[e~  
sFileName = sName; D2,z)O%VK  
this.nSplitter = nSpiltter; j8sH#b7Z  
-c}, :G"  
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} H/"lAXfb  
3dDX8M?  
]$,UPR/3  
public String getSSiteURL() H~E(JLcU  
{ &RTX6%'KY  
return sSiteURL; jH6&q
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} "kA*Vc#  
%DQhM,c@  
;-Jb1"5  
public void setSSiteURL(String value) "$}
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{ :(H>2xS,s  
sSiteURL = value; %/rMg"f:  
} WsDM{1c  
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public String getSFilePath() .n=Z:*JqQ  
{ 0{j&6I2  
return sFilePath; yA3wtm/?  
} Tdc3_<1  
_fwb!T}$  
FPJd|  
public void setSFilePath(String value) `~W-Xx  
{ g38&P3/
 
sFilePath = value; ~I(Hc.Q  
} ZlojbL@|4  
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1* ]Ev  
public String getSFileName() 8x[YZ@iM-  
{ OK{xuX8u  
return sFileName; ILic.@st  
} Nlj^Dm  
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public void setSFileName(String value) {bPV)RL:  
{ M+!x}$&v  
sFileName = value; ]0r|_)s  
} <vUVP\u~$  
<s@-:;9~  
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public int getNSplitter() dgo3'ZO  
{ Eaqca{%/^  
return nSplitter; Cbs5dn(Y  
} -TV?E%r  
,]5Ic.};p  
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public void setNSplitter(int nCount) -ti{6:H8  
{ dz[ bm<T7  
nSplitter = nCount; }17.~  
} {w <+_++  
} Xq4|uuS-O  
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/* |~<N -~.C  
**Utility.java xE-7P|2  
*/ p#K
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package NetFox; 7'NS9|  
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public class Utility { \b*X:3g*  
N:"C+a(  
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public Utility() n,O5".aa<  
{ M|io4+sy  
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nIfCF,
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} Fd\e*ww'  

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//线程睡眠 {I{:GcS  
public static void sleep(int nSecond)  8%RI7Mg  
{ W >
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try{ sn{AwF%  
Thread.sleep(nSecond); VK3it3FI>3  
}
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catch(Exception e) v0l_w  
{ <EO<x D=:  
e.printStackTrace (); G"y.Z2$  
} )fU(AXSP  
} 9x`4
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//日志 q\9d6u=Gm  
public static void log(String sMsg) y:}sD_m0W  
{ ,,=apyr#&  
System.err.println(sMsg); #<CIFV
H  
} +1;'B4  
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ZYtiMBJ  
public static void log(int sMsg) EA{U!b]cU  
{ +iF 1sC_  
System.err.println(sMsg); ?n'OFpd  
} `Xo4q3  
} '5H4z7)  
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/* %(LvE}[RJ  
**TestMethod.java B/eaqJ  
*/ d34Y'r  
package NetFox; 4Nmea-!*  
&$ p[  
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public class TestMethod { t%+$"nP  
{0's~U+@  
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public TestMethod() _ 6:ww/  
{ ///xx/weblogic60b2_win.exe ESDB[ O+`x  
try{ 68x}w Ae  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); D[>W{g $  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 
wRVD_?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); y(8d?]4:_  
fileFetch.start(); BXTN>d27  
} V-vlTgemwc  
catch(Exception e){e.printStackTrace ();} ')nnWlK  
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}  wOHEv^,  
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public static void main(String[] args) o=9'  
{ Fp:3#Bh  
new TestMethod(); K+mU_+KRp  
} ?'2 v.5TQt  
} .Z5[_'T
  
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