http断点续传简单实现（java)

/* q5L51KP2  
**SiteFileFetch.java Y\0}R,]a-  
*/ 03j]d&P%d  
package NetFox; ~l2aNVv;  
import java.io.*; LF0sH)e]  
import java.net.*; (os$B  
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public class SiteFileFetch extends Thread { > 0<)=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean y?SyInt  
long[] nStartPos; //开始位置 X(7qZ P~  
long[] nEndPos; //结束位置 b^[F""!e  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7+hK~  
long nFileLength; //文件长度 d`1I".y  
boolean bFirst = true; //是否第一次取文件 HD N9.5S  
boolean bStop = false; //停止标志 wW"z  
File tmpFile; //文件下载的临时信息 +S))3 5N[  
DataOutputStream output; //输出到文件的输出流 #Eb5:;  
",)Qc!^P$  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "}Me}S<  
public SiteFileFetch(SiteInfoBean bean) throws IOException z%/N!RLW  
{ 1bw{q.cmD  
siteInfoBean = bean; RyRpl*^
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b$eXFi/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); t^ZV|s
1  
if(tmpFile.exists ()) !p1qJ
[  
{ Ssk}e=]  
bFirst = false; 7$rjlVe  
read_nPos(); qp}Ma8+  
} !pJeA)W;  
else *9p |HX=  
{
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nStartPos = new long[bean.getNSplitter()]; 9 fMau  
nEndPos = new long[bean.getNSplitter()]; 2!Bd2  
} -rKO
)}  
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} )a3IQrf=  
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public void run() F]mgmYD%  
{ $3,ryXp7  
//获得文件长度 ;}z\i  
//分割文件 u0`%+:]0  
//实例FileSplitterFetch ]qB:PtX  
//启动FileSplitterFetch线程 *GUAO){'  
//等待子线程返回 MC&\bf  
try{ _s
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if(bFirst) *.&HD6Qr  
{ *H[Iq!@  
nFileLength = getFileSize(); _ %%Z6x(  
if(nFileLength == -1)
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{ zS< jd~  
System.err.println("File Length is not known!"); 2Dd|~{%  
} <[GYLN[0Q  
else if(nFileLength == -2) v=95_l  
{ MZ+e}|!4,  
System.err.println("File is not access!"); 8J)xzp`*)  
} VxFOYC>p  
else MV=9!{`  
{ *z'yk*  
for(int i=0;i<nStartPos.length;i++) OTZ_c1
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{ rfw-^`&{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wC-Rr^q  
} tDDy]==E  
for(int i=0;i<nEndPos.length-1;i++) G4 G5PXi  
{ U=8@@yE  
nEndPos = nStartPos[i+1]; i*eAdIi  
} 4'p=p#o  
nEndPos[nEndPos.length-1] = nFileLength; )fdE6  
} *;|`E(  
} 0hZ1rqq8C  
{7MjP+\  
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//启动子线程 \(p{t  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u>
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for(int i=0;i<nStartPos.length;i++) |Oag,o"  
{ p h[\)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h3gWOU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IHC1G1KW=A  
nStartPos,nEndPos,i);
:D7|%KK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oRp:B&  
fileSplitterFetch.start(); !jqWwi  
} //Ai.Q.J[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LEECW_:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [\R>Xcu>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [_xyl e  
nEndPos = " + nFileLength); AOrHU M[I  
// fileSplitterFetch[nPos.length-1].start(); D5?phyC[Z  
X bkb5EkA  
7~M<cD  
//等待子线程结束 yg]2erR  
//int count = 0; YD
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//是否结束while循环 CVXytS?@x  
boolean breakWhile = false; *^ \FIUd  
69#8Z+dw7  
x
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while(!bStop) $\AEWFB  
{ 2>em0{e  
write_nPos(); ngi<v6i  
Utility.sleep(500); T@^]i&  
breakWhile = true; N]5m(@h  
z(c9,3  
b]gY~cbI8  
for(int i=0;i<nStartPos.length;i++) 8Z85D  
{ f+vVR1  
if(!fileSplitterFetch.bDownOver) 3]JZu9#  
{ (P6vOo  
breakWhile = false; 6g>)6ux>aV  
break; v
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} 1@XgTL4  
} 5+X_4lEJK(  
if(breakWhile) c#xP91.m  
break; `"k9wC1  
6@4n'w{"  
K X]oE+:  
//count++; i[semo\E  
//if(count>4) rn.\tDeA  
// siteStop(); cy~oPj]j  
} =FW5Tkw0  
AW5iV3  
}1+%_|Y-E  
System.err.println("文件下载结束！"); DlE_W+F  
} #p y
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catch(Exception e){e.printStackTrace ();} K'6[J"dB  
} ,ZI\dtl  
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//获得文件长度 m(sXk}e;1  
public long getFileSize() N~,_`=yRx  
{ <M[U#Q~?~e  
int nFileLength = -1; $M"0BZQ?y!  
try{ :XT?jdg  
URL url = new URL(siteInfoBean.getSSiteURL()); G@d`F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e&X>F"z2  
httpConnection.setRequestProperty("User-Agent","NetFox"); lj&>cScC  
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8V4V3^_xs  
int responseCode=httpConnection.getResponseCode(); \+qOO65/+  
if(responseCode>=400) ;7
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{ i+M*J#'  
processErrorCode(responseCode); -.vDF?@G  
return -2; //-2 represent access is error 4f1D*id*`#  
} 1(`M~vFDK  
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>R,?hWT  
String sHeader; 9(VRq^Z1  
BH:  
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for(int i=1;;i++) w!q&  
{ I6OSC&A`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <6N_at3  
//Utility.log(in.readLine()); )wf\F6jN  
sHeader=httpConnection.getHeaderFieldKey(i); [5pCL0<c@  
if(sHeader!=null) W7G9Kx1Y  
{ Ae|P"^kZ  
if(sHeader.equals("Content-Length")) ,J
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{ Sw! j=`O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); & QZVq"  
break; L{ ^4DznI  
} , &' Y  
} -a) T6:e  
else hH+bt!aH  
break; %]Cjhs"v  
} @sf90&f  
} <lFY7'aY  
catch(IOException e){e.printStackTrace ();} m7 XjP2  
catch(Exception e){e.printStackTrace ();} IKf`[_,t]  
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Utility.log(nFileLength); .`LgYW  
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return nFileLength; _dmL}t-  
} Ge}$rLu]0  
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//保存下载信息（文件指针位置） r*cjOrvI  
private void write_nPos() WL~`u  
{ ?e
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try{ >riq9
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ,hE/II`-d'  
output.writeInt(nStartPos.length); %RFYm  
for(int i=0;i<nStartPos.length;i++) $U'3ME
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{ `facFt[
\  
// output.writeLong(nPos); E#h~V5Tf  
output.writeLong(fileSplitterFetch.nStartPos); 6/y*2z;  
output.writeLong(fileSplitterFetch.nEndPos); $j`<SxJ>  
} $Qq_qTJu?G  
output.close();  ~u/@rqF  
} FP;":iRL  
catch(IOException e){e.printStackTrace ();} Yk>8g;<  
catch(Exception e){e.printStackTrace ();} {,V$*  
} o8D{dS>,PL  
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vo b$iS`>=  
//读取保存的下载信息（文件指针位置） L[]^{ O
 
private void read_nPos() ^-L{/'[8M  
{ (n=Aa;  
try{ 9qeZb%r&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }vsO^4Sjc  
int nCount = input.readInt(); H0tF  
nStartPos = new long[nCount]; eYDgEM  
nEndPos = new long[nCount]; <[8@5?&&  
for(int i=0;i<nStartPos.length;i++) Riq|w+Q  
{ foyB{6q8  
nStartPos = input.readLong(); o>K &D$J;O  
nEndPos = input.readLong(); As}eUm)B5c  
} zn[QvY  
input.close(); `G0*l|m>  
} a8NVLD>7}  
catch(IOException e){e.printStackTrace ();} O"QHb|j  
catch(Exception e){e.printStackTrace ();} {|p"; uJ  
} ;r@!a!NLB  
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private void processErrorCode(int nErrorCode) 4[_L=zD  
{ ~1d!hq?/q  
System.err.println("Error Code : " + nErrorCode); GMTor  
} zze z~bv7:  
8vO;IK]9b^  
=?+w)(*0c  
//停止文件下载 xtsL8-u f  
public void siteStop() 4[(?L{  
{ Lv3XYZ
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bStop = true; Xvq^1Y?  
for(int i=0;i<nStartPos.length;i++) 2mLUdx~c  
fileSplitterFetch.splitterStop(); Ik-oI=>.  
1(#RN9   
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} :r^klJ(m  
} @4&, #xo  
//负责部分文件的抓取 p~FQcW'a~  
**FileSplitterFetch.java ,N0uR@GN  
*/ )8bFGX7|  
package NetFox; @bY?$fj_u  
c G*(C
  
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import java.io.*; 1M=   
import java.net.*; 3~:0?Zuq  
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public class FileSplitterFetch extends Thread { hLSTSD}  
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String sURL; //File URL
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long nStartPos; //File Snippet Start Position UIz:=DJ  
long nEndPos; //File Snippet End Position E0
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int nThreadID; //Thread's ID 
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boolean bDownOver = false; //Downing is over ,FY-d$3)  
boolean bStop = false; //Stop identical y]<#%Fh  
FileAccessI fileAccessI = null; //File Access interface Wge ho  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `i9N)3 X  
{ 7|K3WuLL  
this.sURL = sURL; }E,jR
=@  
this.nStartPos = nStart; Nr%(2[$ =  
this.nEndPos = nEnd; 2Gm-\o&Td"  
nThreadID = id; @~s~/[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位
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} jp%+n  
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public void run() wy YtpW  
{ |G)Y8 #D  
while(nStartPos < nEndPos && !bStop) Q g$($   
{ {v,{x1  
})KJ60B  
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try{ di--:h/  
URL url = new URL(sURL); ,TEuM|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ) b
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httpConnection.setRequestProperty("User-Agent","NetFox"); ENO? ;  
String sProperty = "bytes="+nStartPos+"-"; b~jIv:9T  
httpConnection.setRequestProperty("RANGE",sProperty); epn#qeX  
Utility.log(sProperty); !O 4<I_EY{  
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InputStream input = httpConnection.getInputStream(); G l_\Vy  
//logResponseHead(httpConnection); A*a7\id!y  
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byte[] b = new byte[1024];  oHOW5  
int nRead; Q!YF!WoBX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) IF5sqv  
{ \QliHm!  
nStartPos += fileAccessI.write(b,0,nRead); El'yiJ  
//if(nThreadID == 1) 75kKDR}6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xrfPZBLy  
} h4tC. i~k  
r|*:9|y{"/  
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Utility.log("Thread " + nThreadID + " is over!"); '!Hhd![\=|  
bDownOver = true; O%fUm0O d  
//nPos = fileAccessI.write (b,0,nRead); B*y;>q "{U  
} h (qshbC}  
catch(Exception e){e.printStackTrace ();} P87ld._  
} #fwzFS \XL  
} Ica3  
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//打印回应的头信息 y+?=E g  
public void logResponseHead(HttpURLConnection con) +mivqR~{{  
{ :G
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for(int i=1;;i++) S|~i>  
{ yQ8M >H#J  
String header=con.getHeaderFieldKey(i); ;&If9O1  
if(header!=null) O;UiYrXU  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8n;kK?  
Utility.log(header+" : "+con.getHeaderField(header)); 2dXU0095  
else XIqv{w  
break; MJ1W*'9</W  
} ==nYe{2  
} w
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public void splitterStop() xR*5q1j  
{ ylkpYd  
bStop = true; y>@v>S  
} RlU;v2Kch  
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} hK:#+hg,  
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`oB'(  
/* b;Hm\aK  
**FileAccess.java :/>7$)+  
*//文件访问(定位，写) >BJ2v=RA  
package NetFox; 3?.6K0L  
import java.io.*; ^Yf3"D?&  
w/qQ(]n8  
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public class FileAccessI implements Serializable{ -"2<h:#  
v;K{|zUdB  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 RcY6V_Qx  
RandomAccessFile oSavedFile; se~ *<5  
long nPos; :|?~B%-p[  
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public FileAccessI() throws IOException Nn
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{ enPzy:C  
this("",0); Coga-: 2vu  
} yonJd  
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public FileAccessI(String sName,long nPos) throws IOException `DI{wqV9  
{ <FXQxM5"  
oSavedFile = new RandomAccessFile(sName,"rw"); @:S$|D~  
this.nPos = nPos; p3V9ikyy  
oSavedFile.seek(nPos); A28ZSL  
} @uQ%o%Ru6  
r$b:1C~  
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public synchronized int write(byte[] b,int nStart,int nLen) 9QX&7cs&[  
{ on]\J  
int n = -1;  ~Y1"k]J  
try{ Hi9 G^Q  
oSavedFile.write(b,nStart,nLen); o%vIkXw  
n = nLen; N5:D8oWWXR  
} nvU+XCx  
catch(IOException e) Ytl:YzXCi  
{ o@qN#Mg?>}  
e.printStackTrace (); [37f#p  
} VaD:  
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return n; 1.hOE>A%  
} ;yRwoTc)Y  
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} `l HKQwu  
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/* >xxXPvM<`  
**SiteInfoBean.java 0!3!?E <  
*/ yC9:sQ'k  
package NetFox; / e~  
t:?<0yfp&  
B|$\

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public class SiteInfoBean { H @3$1h&YS  
'0\0SL   
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private String sSiteURL; //Site's URL OGS
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private String sFilePath; //Saved File's Path UMHuIA:%U  
private String sFileName; //Saved File's Name 1G e)p4  
private int nSplitter; //Count of Splited Downloading File sRkz WMl  
o'x_g^ Y  
}M"-5K}  
public SiteInfoBean() >i><s>=I`  
{//nSplitter的缺省值为5 "wc`fg"3  
//default value of nSplitter is 5 +^^S'mP8  
this("","","",5); b&hF')_UOz  
} UiGUaBmF*  
"k>{b:R|  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]1/W8
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{ ?RrC~7~  
sSiteURL= sURL; 5n|MA  
sFilePath = sPath; Li?{e+g  
sFileName = sName; @Z3[c[D)9  
this.nSplitter = nSpiltter; Q%gY.n{=  
~2, wI<Nz  
Og&0Z)%  
} GI'&g@?u  
F1Zk9%L%9$  
4fU5RB7%  
public String getSSiteURL() 1s^$oi}  
{ kVB}r.NHP  
return sSiteURL; L!G9O]WB  
} ^>P@5gcoE(  
3rXL0&3w%  
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public void setSSiteURL(String value) <.y^  
{ O"2wV +9  
sSiteURL = value; .R<s<]  
} erAZG)  
@=aq&gb  
>$k4@eg!  
public String getSFilePath() 6`$,-(J=  
{ EF_h::A_  
return sFilePath; OTy4"%  
} { V=:O  
*;\ K5  
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public void setSFilePath(String value) z9uEOX&2\  
{ Eo25ir%  
sFilePath = value; eAenkUBz6,  
} e\|E; l  
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public String getSFileName() FZ}C;yUPD  
{ w oY)G7%  
return sFileName; ZT3jxwe  
} U_zpLpm^  
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public void setSFileName(String value) a#^4xy:  
{ <R]Wy}2-  
sFileName = value;  onS{  
} `5~o=g  
8Vg`
;_-  
OU Yb-  
public int getNSplitter() ggYIq*4  
{ T_;G))q'  
return nSplitter; DrV
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} F4aJr%!\6S  
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8
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public void setNSplitter(int nCount) P[|BWNei  
{  }@Ll!
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nSplitter = nCount; A.'`FtV  
} hTNYjXj  
} JY,l#?lM{  
,R9f;BR  
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/* y&O_Jyg<  
**Utility.java dT0z^SG  
*/ Zqe[2()  
package NetFox; ph|2lLZ  
ph$&f0A6Xc  
(x*2BEn|  
public class Utility { |RbUmuj  
"~,(
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f*R_\  
public Utility() g275{2G9  
{ K+aJ`V  
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TJGKQyG$L  
} tX2>a  
J~ gkGso  
//线程睡眠 |GLn 9vw7S  
public static void sleep(int nSecond) eB1eUK>  
{ SUQ}^gn]  
try{ Vm5P@RU$w;  
Thread.sleep(nSecond); Yhv`IV-s  
}
!nD[hI8P  
catch(Exception e) oCru5F  
{ $@ #G+QQ_  
e.printStackTrace (); TlZlE^EE<  
} >!ZyykAs  
} {10+(Vl  
Y&!McM!Jw  
//日志 P)o[p(  
public static void log(String sMsg) F@*r%[S/  
{ ?wiq 3f6  
System.err.println(sMsg); jzOMjz~:)  
} *~aI>7H  
YUE1 '}  
hE3jb.s(>  
public static void log(int sMsg) qcoZ2VJ hh  
{ Sv]"Y/N  
System.err.println(sMsg); Z(clw  
} N`mC_)  
} @eD~FNf-]  
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f\%X7.  
/* xVmUmftD  
**TestMethod.java u*YuU%H=  
*/ L bK1CGyA  
package NetFox; 7}HA_@[  
,2L,>?r6  
<8}9s9Nk  
public class TestMethod { T)?@E/VaS  
WlJRKM2  
^L2Zo'y [  
public TestMethod() ="Pyw
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{ ///xx/weblogic60b2_win.exe Lm2cW$s  
try{ 0~I) /T  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j1C0LP8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g&20F`.N*>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9"v
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fileFetch.start(); JL*]9$o  
} (6_/n&mF  
catch(Exception e){e.printStackTrace ();} u=N;P  
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} 53#5p;k  
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public static void main(String[] args) a\.?{/  
{ z:q'?{`I  
new TestMethod(); \fGYJ37  
} 9#ay(g  
} < 2r#vmM  
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