http断点续传简单实现（java)

/* d5\1-d_uz  
**SiteFileFetch.java }:mI6zsNj  
*/ c`.:"i"k3  
package NetFox; r&[~/m8zl  
import java.io.*; EyeLC6u  
import java.net.*; T82_`u  
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#  
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public class SiteFileFetch extends Thread { -
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SiteInfoBean siteInfoBean = null; //文件信息Bean Rv-o__C!  
long[] nStartPos; //开始位置 39j d}]e  
long[] nEndPos; //结束位置 #r:`bQ0;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rA`\we)  
long nFileLength; //文件长度 $ZU(bEUOG  
boolean bFirst = true; //是否第一次取文件 H1[aNwLr  
boolean bStop = false; //停止标志 zi ,Rk.  
File tmpFile; //文件下载的临时信息 h[]N=X  
DataOutputStream output; //输出到文件的输出流 *LRGfk+h  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） l 3K8{H
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public SiteFileFetch(SiteInfoBean bean) throws IOException nf4P2<L!  
{ IMZKlU3  
siteInfoBean = bean; 'dzp@-\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); L@Z &v'A  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4.'EEuRw\}  
if(tmpFile.exists ()) + LwoBn>6  
{  kTz  
bFirst = false; oc(bcU  
read_nPos(); bwJi[xF  
} n@Ag`}  
else eFQi K6`i  
{ 4Le5Ms/  
nStartPos = new long[bean.getNSplitter()]; Z|c9%.,  
nEndPos = new long[bean.getNSplitter()]; Lvq]SzOw  
} FQFENq''B  
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} o0'av+e7  
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public void run() j,xPN=+hT  
{ }gW/heUE  
//获得文件长度 w8 $Qh%J'<  
//分割文件 6iG<"{/U5  
//实例FileSplitterFetch ib_Gy77Os  
//启动FileSplitterFetch线程 X6,9D[Nw  
//等待子线程返回 ^wa9zs2s;/  
try{ bJm0  
if(bFirst) ~ ""MeaM8[  
{ q4i8Sp>  
nFileLength = getFileSize(); j6vZ{Fx;w  
if(nFileLength == -1) $:[BB,$  
{ #!jRY!2Vt  
System.err.println("File Length is not known!"); >!1f`  
} s8[9YfuW  
else if(nFileLength == -2) 4C%>/*%8>  
{ ?+5{HFx  
System.err.println("File is not access!"); I_G>W3  
} \bic.0-  
else j/D)UWkR  
{ 8>Z$/1Mh  
for(int i=0;i<nStartPos.length;i++) EcoUpiL%2  
{ ^P/D8cXa4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b@/ON}gX  
} cJEz>Z6[  
for(int i=0;i<nEndPos.length-1;i++) dyzwJ70K  
{ 2^6TrZA7M6  
nEndPos = nStartPos[i+1]; (QSWb>np  
} ?d<:V.1U@  
nEndPos[nEndPos.length-1] = nFileLength; GB?#1|,  
} \GvY`kt3  
} AvE^ F1  
8(5E<&JP  
`^L<db^A  
//启动子线程 \>Rwg=Lh  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .)>/!|i  
for(int i=0;i<nStartPos.length;i++) N&APq
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{ {(}w4.!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =t
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), SU O;  
nStartPos,nEndPos,i); `u~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _qt;{,t  
fileSplitterFetch.start(); ~f10ZB_k>'  
} \'+{X(]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i @9Qb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I"sobZ`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W}k?gg=  
nEndPos = " + nFileLength); P}9Y8$Y>U  
// fileSplitterFetch[nPos.length-1].start(); &JhIn%=-  
0ITA3v8{  
E#$_uZ4  
//等待子线程结束 pq?[wp"  
//int count = 0; n,jE#Z.D  
//是否结束while循环 ./nYXREO|  
boolean breakWhile = false; udD*E~1q  
7G[ GHc>  
#)mkD4  
while(!bStop) [gkRXP[DGs  
{ ru/zLj:  
write_nPos(); h0GdFWN  
Utility.sleep(500); /P!X4~sTM  
breakWhile = true; wYQ1Z  
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for(int i=0;i<nStartPos.length;i++) $qtU  
{ /-{O\7-D  
if(!fileSplitterFetch.bDownOver) N(
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{ 'RV\}gqZ  
breakWhile = false; _`@Xy!Ye  
break; +z(,A  
} m0A@jWgd  
} B#GZmv1  
if(breakWhile) !qXq y}?w  
break; GQ-e$D@SfB  
0|s$vqc  
udEb/7ZL  
//count++; c+b:
K  
//if(count>4) DAMpR3  
// siteStop(); hw ;dm  
} *T>#zR{  
;8L+_YCa  
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System.err.println("文件下载结束！"); W_BAb+$aF  
} (#-=y~%  
catch(Exception e){e.printStackTrace ();} /[|}rqX(  
} 
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//获得文件长度 oX2DFgz  
public long getFileSize() lYZ@a4TA  
{ GrLM${G  
int nFileLength = -1; c(Uj'uLc  
try{ U)`3[fo  
URL url = new URL(siteInfoBean.getSSiteURL()); cB|Cy{%
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hDB
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httpConnection.setRequestProperty("User-Agent","NetFox"); 7:VEM;[d  
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int responseCode=httpConnection.getResponseCode(); !QQ<Ai!E  
if(responseCode>=400) k\Z;Cmh>  
{ neB.Wu~WH  
processErrorCode(responseCode); +2V%'{:  
return -2; //-2 represent access is error \}u7T[R=`  
} Owh*KY:  
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String sHeader; E2qB:  
z6FbM^;;  
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for(int i=1;;i++) S& ,Ju%  
{ SrQ4y`?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &v3D" J  
//Utility.log(in.readLine()); f#;ubfi"z  
sHeader=httpConnection.getHeaderFieldKey(i); rY[3_NG%  
if(sHeader!=null) hpqHllL  
{ ,NaV ["9$  
if(sHeader.equals("Content-Length")) ^Kw&=u  
{ a8bX"#OR&N  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K4?t' dd]  
break; JO&;bT<  
} aR="5{en{:  
} uGP[l`f|FQ  
else 9LqMQv"xW  
break; (5Z8zNH`3  
} 8g# c%eZ  
} mJGO)u&  
catch(IOException e){e.printStackTrace ();} V(lK`dY  
catch(Exception e){e.printStackTrace ();} GG@I!2,_  
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Utility.log(nFileLength); c]%;^)  
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return nFileLength; %S >xSqX  
} _ bXVg3oDt  
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//保存下载信息（文件指针位置） u n?
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private void write_nPos() 1kvPiV=X>  
{ dt-Qu},8-  
try{ 0^<Skm27"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~!3t8Hx6  
output.writeInt(nStartPos.length); [0%yJH  
for(int i=0;i<nStartPos.length;i++) NSMjr_  
{ @b::6n/u  
// output.writeLong(nPos); OQytgXED  
output.writeLong(fileSplitterFetch.nStartPos); Zzw}sZ?8  
output.writeLong(fileSplitterFetch.nEndPos); 5(iSOsb  
} lQp89*b?=U  
output.close(); AND7j
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} m{:"1]  
catch(IOException e){e.printStackTrace ();} (!3Yc:~RE  
catch(Exception e){e.printStackTrace ();} *tTP8ZCQ[  
} `G"|MM>P  
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//读取保存的下载信息（文件指针位置） D+ah ok  
private void read_nPos() hb 
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{ h"Vp
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try{ dAYI DE  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 'WKu0Yi^'  
int nCount = input.readInt(); "B|nhd  
nStartPos = new long[nCount]; dxzv
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nEndPos = new long[nCount]; S F&M (=w<  
for(int i=0;i<nStartPos.length;i++) p<of<YU)  
{ ESC  
nStartPos = input.readLong(); ql{^"8x  
nEndPos = input.readLong(); =R8f)UQYx  
} 8FO1`%8Oe  
input.close(); $Q`yNEc  
} "J]f0m=  
catch(IOException e){e.printStackTrace ();} 4 o3)*  
catch(Exception e){e.printStackTrace ();} ZfFIX5Qd\  
} O_r^oH  
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private void processErrorCode(int nErrorCode) pX>ua5Z  
{ ]iz_w`I\  
System.err.println("Error Code : " + nErrorCode); q=P f^Xp  
}
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//停止文件下载 |Q5H9<*  
public void siteStop() k9*J*7l-m  
{ ax-=n(   
bStop = true; ^;V}l?J_s  
for(int i=0;i<nStartPos.length;i++) QE7+rBa  
fileSplitterFetch.splitterStop(); 0=N4O!X9
 
SjZd0H0  
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} ~hS .\h  
} K:}h\ In  
//负责部分文件的抓取 (A7T}
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**FileSplitterFetch.java *)j@
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*/ (/T+Wpy?  
package NetFox; XoDJzrL#  
 )x$!K[=  
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import java.io.*; >[Xm|A#  
import java.net.*; sl~b\j  
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public class FileSplitterFetch extends Thread { fl!mYCPv  
#[no~&E  
C#A@)>  
String sURL; //File URL )v${&H  
long nStartPos; //File Snippet Start Position &tlR~?$e*  
long nEndPos; //File Snippet End Position ,DE(5iDS  
int nThreadID; //Thread's ID 'bLP~  
boolean bDownOver = false; //Downing is over er(8}]X8Q  
boolean bStop = false; //Stop identical CMC?R,d  
FileAccessI fileAccessI = null; //File Access interface P/FrE~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Nawp t%  
{ $@_
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this.sURL = sURL; l0gH(28K  
this.nStartPos = nStart; 6t
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this.nEndPos = nEnd; "AT&!t[J  
nThreadID = id; bZxv/\
  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o:Ln._bj  
} R
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 ]a78tTi  
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public void run() \z2vV+f  
{ M#=Y~PU  
while(nStartPos < nEndPos && !bStop) fy9uLl}h  
{ vad|Rpl  
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}phz7N9  
try{ 'g. :MQ8  
URL url = new URL(sURL); '*8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Xyb8u})p'  
httpConnection.setRequestProperty("User-Agent","NetFox"); {\P?/U6~f  
String sProperty = "bytes="+nStartPos+"-"; q A.+U:I8  
httpConnection.setRequestProperty("RANGE",sProperty); |c<XSX?ir  
Utility.log(sProperty); CKJAZ2  
4#TnXxL  
#o"tMh!f  
InputStream input = httpConnection.getInputStream(); J09*v)L  
//logResponseHead(httpConnection); w(aUEWYL  
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byte[] b = new byte[1024]; H(MB5  
int nRead; #X4LLS]VV  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a a4$'8s  
{ !&Z*yH  
nStartPos += fileAccessI.write(b,0,nRead); uRP Ff77  
//if(nThreadID == 1) 2q12yY f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N0]z/}hd@  
} B<A:_'g  
_wMc*kjJO  
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Utility.log("Thread " + nThreadID + " is over!"); X88F>1}  
bDownOver = true; 8a7YHUL<3i  
//nPos = fileAccessI.write (b,0,nRead); QT_Srw@  
} L+_8QK<  
catch(Exception e){e.printStackTrace ();} ^n t~-%  
} JFe4/ V  
} g .3
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$,!hD\a  

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//打印回应的头信息 ,A
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public void logResponseHead(HttpURLConnection con) Nc,*hsx'  
{ fQxSMPWB  
for(int i=1;;i++) GM:,CJ?  
{ 4>l0V<  
String header=con.getHeaderFieldKey(i); &/HoSj>HS  
if(header!=null) ;D:=XA%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )#C_mB$-#  
Utility.log(header+" : "+con.getHeaderField(header)); S45'j(S=  
else OthG7+eF  
break; $\+"qs)  
} Tu==49  
} JW-|<CJ  
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public void splitterStop() anLbl#UV  
{ Q<dba12  
bStop = true; P?xA$_+  
} 6F,/w:  
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}
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/* g083J}08  
**FileAccess.java K@HLIuz4t  
*//文件访问(定位，写) Ln:lC( '  
package NetFox; ej<`CQ  
import java.io.*; :|=- (z  
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tO7I&LNE  
public class FileAccessI implements Serializable{ -E:(w<];  
n7@j}Q(&?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @$Yb#$/  
RandomAccessFile oSavedFile; rj}(muM,R  
long nPos; D6Dn&/>Zp  
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public FileAccessI() throws IOException @Zj&`/  
{ HXyFj  
this("",0); Q@3B{  
} _g65pxt =Z  
&u("|O)w$  
sLNNcj(Cy>  
public FileAccessI(String sName,long nPos) throws IOException ZxI]I1)  
{ &eU3(F`.  
oSavedFile = new RandomAccessFile(sName,"rw"); f P+QxOz  
this.nPos = nPos; `6UtxJSx  
oSavedFile.seek(nPos); W5|j1He&  
} ),yH=6  
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2HSb.&7-G  
public synchronized int write(byte[] b,int nStart,int nLen) l`*( f9Q  
{ 4Q$!c{Y r  
int n = -1; h+5@I%WX  
try{ LGAX
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oSavedFile.write(b,nStart,nLen); 9]
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n = nLen; `wf|uM  
} Ep<YCSQy$i  
catch(IOException e) RU7!U mf  
{ QsM*wT&aa  
e.printStackTrace (); A
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} Qd?CTYNsv  
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return n; Q4=|@|U0  
} ;sCU[4  
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} q1jN]H  
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MJA~jjy4  
/* z$66\/V']  
**SiteInfoBean.java =D}4X1l  
*/ ~x\Cmu9`  
package NetFox; Z~_8P  
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public class SiteInfoBean { loBtd%wY  
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private String sSiteURL; //Site's URL ,&[7u9@  
private String sFilePath; //Saved File's Path CB6o$U  
private String sFileName; //Saved File's Name TqAtcAurM  
private int nSplitter; //Count of Splited Downloading File (U_wp's  
jAZ >mo[  
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public SiteInfoBean() A*Rn<{U  
{//nSplitter的缺省值为5 o_(0  
//default value of nSplitter is 5 7pP+5&*  
this("","","",5); l0. FiO@_Q  
} #3.\j"b  
z(rK^RT  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /7x\;&bc  
{ HgaZbb>'  
sSiteURL= sURL; ^j
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sFilePath = sPath; X% X$Y6  
sFileName = sName; Hv8H.^D>  
this.nSplitter = nSpiltter; LJj=]_  
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mbGcDG[HQ  
} *Wso3 6an  
l=xt;c!  
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public String getSSiteURL() d+Ds9(gV  
{ R3Ee%0QK  
return sSiteURL; 4~*Y];!Q  
} cLAesj  
6{8/P'@/Zz  
>J@egIKzP  
public void setSSiteURL(String value) 05"qi6tncz  
{ g}m+f]|  
sSiteURL = value; VyY.r#@  
} +YuzpuxjJ  
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public String getSFilePath() A4 5m)wQ  
{
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return sFilePath; 3p&jLFphL  
} ||XIWKF<n2  
nEyIt&>9  
*Q5x1!#z#  
public void setSFilePath(String value) Z}+yI,  
{ 6"+8M 3M l  
sFilePath = value; /BT1oWi1y  
} =U c$D*  
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public String getSFileName() n]v7V&mj\  
{ {@45?L('  
return sFileName; =zOeb/  
} JjQ
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T/NjNEd#  
public void setSFileName(String value) LXNQ
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{ }PZ=`w*O  
sFileName = value; 79wLT\&  
} _ eiF@G  
8%-%AWF]  
Hd374U<8]T  
public int getNSplitter() BGzO!s*@j  
{ hlC%HA  
return nSplitter; O|7yP30?M  
} R6<4"?*r  
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public void setNSplitter(int nCount) 9n 6fXOC  
{ 3q?5OL^$  
nSplitter = nCount; q]XHa,"  
} fhr-Y'  
} )!sa)\E?  
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$rB6<  
/* Y"*:&E2)r  
**Utility.java puF%=i  
*/ "H?QqrKx  
package NetFox; R8 jovr  
v?)SA];  
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public class Utility { uREu2T2  
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public Utility() {R8=}Qo  
{ [e1L{_*l  
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} 4TVwa(cB  
;wgFr.#hp@  
//线程睡眠 VaJfD1zd1  
public static void sleep(int nSecond) Onw24&  
{ c{VJ2NQ+  
try{ 0m&3
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Thread.sleep(nSecond); ,E9d
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} anC+r(jjg9  
catch(Exception e) eO[c lB  
{ 8^vArS;  
e.printStackTrace (); P#*n3&Uu  
} *Ru2:}?MpS  
} %E.S[cf%8&  

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//日志 `)tA YH  
public static void log(String sMsg) HTR1)b  
{ H#Q;"r3  
System.err.println(sMsg); M BVOfEMj  
} |7c`(.  
nh0&'hA  
agT7=hX].  
public static void log(int sMsg) j3P$@<  
{ eM }W6vIn  
System.err.println(sMsg); 8[R1A  
} m8AAp1=  
} l#xw.2bo  
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EY$?^iS  
/* DY.58IHg1  
**TestMethod.java l{Er+)a  
*/ u E.^w;~2=  
package NetFox; _Wma\(3$  
 +>#e=nH  
M5O'=\+,F  
public class TestMethod { }"4roJ  
oIxH3T  
x8
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public TestMethod() h[Mdr  
{ ///xx/weblogic60b2_win.exe s.rT]  
try{ Ay%:@j(E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); De]^&qw(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?!7 SzLll  
SiteFileFetch fileFetch = new SiteFileFetch(bean); c,$mWTC  
fileFetch.start(); WjOH/$(  
} choL%g}  
catch(Exception e){e.printStackTrace ();} c/'M#h)"  
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4m /TW)  
} HfZtL  
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public static void main(String[] args) OL9]*G?F  
{ +*D4(  
new TestMethod();
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} sg$4G:l  
} [#Fg\2bq_y  
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