http断点续传简单实现（java)

/* X uE: dL?  
**SiteFileFetch.java d2Q*1Q@u  
*/ 4j=K3m  
package NetFox; %H\J@{f  
import java.io.*; }NyQ<,+mq&  
import java.net.*; u$^tRz9  
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public class SiteFileFetch extends Thread { Dh8'og)7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean >nSt<e  
long[] nStartPos; //开始位置 +Mijio  
long[] nEndPos; //结束位置 ou-UR

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FileSplitterFetch[] fileSplitterFetch; //子线程对象 :!g|pd[{ag  
long nFileLength; //文件长度 ?110} [jw  
boolean bFirst = true; //是否第一次取文件 M\4`S&  
boolean bStop = false; //停止标志 @~$"&B  
File tmpFile; //文件下载的临时信息 t?G6|3
  
DataOutputStream output; //输出到文件的输出流 2lsUCQI;  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） aA#79LS  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~5&4
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{ 1b1Ab zN
 
siteInfoBean = bean; Q >/,QX  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); seEo)m`d  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); T%)E!:}v  
if(tmpFile.exists ()) {>1FZsR49t  
{
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bFirst = false; !\4B.  
read_nPos(); ?nW>'z  
} T#-;>@a}  
else j~{cT/5Y_  
{ h97#(_wV>  
nStartPos = new long[bean.getNSplitter()]; 6qZ\^ U  
nEndPos = new long[bean.getNSplitter()]; p}JOiiHa  
} I<940PZ  
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} DBHy%i  
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public void run() U)bv,{-q  
{ ,J|,wNDU!K  
//获得文件长度 RX>P-vp  
//分割文件 0uDDaFS  
//实例FileSplitterFetch IANSpWea?  
//启动FileSplitterFetch线程 o0C&ol_  
//等待子线程返回 eo9/  
try{ ~I5hV}ZT  
if(bFirst) >E<ib[vK[  
{ RN(I}]]a  
nFileLength = getFileSize(); &kIeW;X  
if(nFileLength == -1) 0mSP  
{  .
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System.err.println("File Length is not known!"); A!bG2{r  
} p5#x7*xR6  
else if(nFileLength == -2) 2g{tzR_j  
{ *[]E5U  
System.err.println("File is not access!"); X-HE9PT.  
} Y/.C+wW2  
else }aR
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{ lNL=Yu2p_  
for(int i=0;i<nStartPos.length;i++) xW`y7Q}p  
{ 2; ^ME\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Vbl-Ff  
} 1'<C-[1  
for(int i=0;i<nEndPos.length-1;i++) Bx#i?=*W  
{ 4MS<t FH)  
nEndPos = nStartPos[i+1]; 7
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} Kb?{^\FiU  
nEndPos[nEndPos.length-1] = nFileLength; mF*x&^ie  
} ~+dps i  
} GjhTF|  
!CYC7HeF  
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//启动子线程 :ZrJL&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "OjAhKfG  
for(int i=0;i<nStartPos.length;i++) *XTd9E^tXq  
{ sFFQ]ST2p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |EE1S{!24m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <:&vAX L  
nStartPos,nEndPos,i); 2cYBm^o|x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i 6G40!G=)  
fileSplitterFetch.start(); _!',%+  
} yU v YV-7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C.j
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &j4pC$Dj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )Zr9 `3[  
nEndPos = " + nFileLength); =hKAwk/^  
// fileSplitterFetch[nPos.length-1].start(); '{d@Gc6.  
B'
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}sXTZX  
//等待子线程结束 +x"uP  
//int count = 0; h+[6i{  
//是否结束while循环 O_:l;D#i  
boolean breakWhile = false; _nbr%PD,  
X 0y$xC|<  
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while(!bStop) jn2=)KBa_  
{ A"V mxP  
write_nPos(); >7>I1  
Utility.sleep(500); 'Z`7/I4&  
breakWhile = true; KMRPleF  
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for(int i=0;i<nStartPos.length;i++) FO2e7p^Q  
{ PE%$g\#?  
if(!fileSplitterFetch.bDownOver) 1)(>'pY  
{ -* ,CMw  
breakWhile = false; !ZBtXt#P  
break; @[n#-!i  
} 3$\k=q3`#  
} W'[V
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if(breakWhile) 'h*jL@%TT  
break; <gp?}Lk  
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t7+A!7b{  
//count++; s6bsV
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//if(count>4) bHwEd%f  
// siteStop();
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}
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System.err.println("文件下载结束！"); y}odTeq  
} C ^Y\?2h1  
catch(Exception e){e.printStackTrace ();} ~ nsb  
} 4V,.Oi  
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"%-Vrb=:Y  
//获得文件长度 wX,V:QE  
public long getFileSize() ffrIi',@  
{ {OU|'  
int nFileLength = -1; TekUY m!G  
try{ vi,hWz8WB  
URL url = new URL(siteInfoBean.getSSiteURL()); Y?0/f[Ax,y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $coO~qvU  
httpConnection.setRequestProperty("User-Agent","NetFox"); X,QsE{  
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int responseCode=httpConnection.getResponseCode(); kka5=u  
if(responseCode>=400) H9cPtP~a)  
{ @]=40Yj~w  
processErrorCode(responseCode); ks4
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return -2; //-2 represent access is error L|=5jn9 :  
} jJ,_-ui  
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 7GgZ: $d  
String sHeader; $83B10OQ&L  
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for(int i=1;;i++) )[Y B&  
{ %M(RV_R+6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c3vb~l)  
//Utility.log(in.readLine()); cw Obq\  
sHeader=httpConnection.getHeaderFieldKey(i);
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if(sHeader!=null) 4DA34m(  
{ b9.M'P\  
if(sHeader.equals("Content-Length")) 5~*)3z^V  
{ </h^%mnd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >L7s[vKn  
break; ^J'_CA  
} / ;]5X  
} 8H!QekQZ]\  
else rpR${%jc  
break; `9~ %6N?7#  
} ,WT>"9+  
} 3N7H7(IR  
catch(IOException e){e.printStackTrace ();} )g0fN+Mb  
catch(Exception e){e.printStackTrace ();} {0zn~+  
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Utility.log(nFileLength); $<}c[Nm  
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return nFileLength; +{J8,^z#  
} )-C3z  
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//保存下载信息（文件指针位置） qL(Q1O!  
private void write_nPos() RZ".?  
{ zZ5:)YiW-  
try{ }lJ;|kx$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hp\&g2_S0W  
output.writeInt(nStartPos.length); NxT"A)u  
for(int i=0;i<nStartPos.length;i++) tK#R`AQ  
{ UX 1 )((  
// output.writeLong(nPos); JfY*#(
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output.writeLong(fileSplitterFetch.nStartPos); K1B9t{T  
output.writeLong(fileSplitterFetch.nEndPos); 'D\Q$q  
} bx@l6bpQ  
output.close(); &p0e)o~Ux  
} K=g</@L6R  
catch(IOException e){e.printStackTrace ();} t}EMX9SQ  
catch(Exception e){e.printStackTrace ();} qe~x?FO_>  
} wp[Ug2;G  
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 6@S6E(^  
//读取保存的下载信息（文件指针位置） c OYDN[k  
private void read_nPos() okNo-\Dh!  
{ ?1e{\XW  
try{ ;JW_4;-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .])prp8  
int nCount = input.readInt(); .n-#A  
nStartPos = new long[nCount]; y8Va>ul"U  
nEndPos = new long[nCount]; FL0uY0K  
for(int i=0;i<nStartPos.length;i++) yV30x9i!2  
{ QrZ#<{,J5  
nStartPos = input.readLong(); eL!41_QI  
nEndPos = input.readLong(); sV^:
u^  
} ; * [:~5Wc  
input.close(); ~/ %Xm<  
} $o^Z$VmL  
catch(IOException e){e.printStackTrace ();} JzHG5nmB  
catch(Exception e){e.printStackTrace ();} 8`Ya7c>  
} eim+oms  
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private void processErrorCode(int nErrorCode) tYS4"Nfb+  
{ U, 6iT  
System.err.println("Error Code : " + nErrorCode); +n3I\7G>  
} s='+[*&&  
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//停止文件下载 eRauyL"Q+  
public void siteStop() B@,9Cx564  
{ {|;a?]?  
bStop = true; K|& f5w  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); Mf}M/Fh  
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} )8Va%{j  
} ~6vz2DuB=  
//负责部分文件的抓取 >yIJ8IDF  
**FileSplitterFetch.java xo:kT)  
*/ "L~(%Nx3  
package NetFox; 6|TSH$w_  
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import java.io.*; dWqn7+:  
import java.net.*; `]Bb0h1![  
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public class FileSplitterFetch extends Thread { ~z,o):q1}  
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String sURL; //File URL !e$gp(4  
long nStartPos; //File Snippet Start Position 5J5si<v25  
long nEndPos; //File Snippet End Position / )0hsQs  
int nThreadID; //Thread's ID w =^.ICyb@  
boolean bDownOver = false; //Downing is over UZZJtQt  
boolean bStop = false; //Stop identical <hT\xBb:  
FileAccessI fileAccessI = null; //File Access interface ^;C&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException '<Z[e`/  
{ ^0VL](bD>  
this.sURL = sURL; h}bfZL  
this.nStartPos = nStart; E?m~DYnU  
this.nEndPos = nEnd; "LyD  
nThreadID = id; cby#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0=d2_YzSf  
} "S#FI  
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public void run() Zg;$vIhn  
{ =x~I'|%3  
while(nStartPos < nEndPos && !bStop) b@:OlZ~%  
{ 18g_v"6o  
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 %Bq~b$  
try{ Bx\&7|,x  
URL url = new URL(sURL); V0ze7tSG[f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f^c+M~\JKj  
httpConnection.setRequestProperty("User-Agent","NetFox"); qsj{0Go  
String sProperty = "bytes="+nStartPos+"-"; ^E&PZA\,;  
httpConnection.setRequestProperty("RANGE",sProperty); b*|~F  
Utility.log(sProperty); =Q#I@SVp2$  
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InputStream input = httpConnection.getInputStream(); g40Hj Y  
//logResponseHead(httpConnection); OATdmHW  
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byte[] b = new byte[1024]; +z >)'#  
int nRead; OG\i?N  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )0{`}7X  
{ Aq i:h]x  
nStartPos += fileAccessI.write(b,0,nRead); m0HK1'  
//if(nThreadID == 1) .
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =w2 4(S  
} PK*Wu<<  
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Utility.log("Thread " + nThreadID + " is over!"); [g}Cve#i  
bDownOver = true; F!z0N&#  
//nPos = fileAccessI.write (b,0,nRead); \ovs[&  
} f}otIf  
catch(Exception e){e.printStackTrace ();} a[{$4JpK  
} mvn- QP~"  
} (f/(q-7VWt  
-YoL.`s1  
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//打印回应的头信息 6jE.X  
public void logResponseHead(HttpURLConnection con) &OR(]Wt0  
{ ;$p!dI\-Q  
for(int i=1;;i++) IUMv{2C  
{ Pwh}hG1sa  
String header=con.getHeaderFieldKey(i); D:P(;  
if(header!=null) z4u&#.bU  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <T2O^  
Utility.log(header+" : "+con.getHeaderField(header)); x6ghO-s  
else (*-wiL  
break; /V
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} GT{4L]C  
} 72HA.!ry  
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public void splitterStop() /$^Tou/v  
{ :X>Wd+lY:_  
bStop = true; Q_mphW:[  
} LI,wSTVjC  
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~  
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}
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/* *V>?m6y/  
**FileAccess.java 7FX4|]  
*//文件访问(定位，写) vPkLG*d8  
package NetFox; jIh1)*]054  
import java.io.*; @]uqC~a^  
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public class FileAccessI implements Serializable{ ZL|aB886  
wMS%/l0p1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]n^iG7aB?  
RandomAccessFile oSavedFile; Pn
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long nPos; x&B&lFmo8  
}#z1>y!#  
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public FileAccessI() throws IOException 4o>y9  
{ Vl.,e1)6  
this("",0); :Cq73:1\B  
} ;i@S}LwL  
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public FileAccessI(String sName,long nPos) throws IOException Xv1vq -cM  
{ m*^)#  
oSavedFile = new RandomAccessFile(sName,"rw"); zt.kNb  
this.nPos = nPos; OqtGKda  
oSavedFile.seek(nPos); =D<0&M9C  
} ]545:)Q1  
(\\;A?  
D4
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public synchronized int write(byte[] b,int nStart,int nLen) @3`5(xwzm  
{ =rKJJa N  
int n = -1; b.*LmSX#  
try{ c^}G=Z1@  
oSavedFile.write(b,nStart,nLen); yan^\)HZ  
n = nLen; \Qml~?$@lH  
} tYA@J["^  
catch(IOException e) /x3*oO1  
{ 161P%sGx2  
e.printStackTrace (); ,Ckcc  
} !Asncc G  
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return n; AVT% AS  
} ^'QO!{7f  
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} U4XW Kwq  
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^h?fr`  
/* @O"7@%nu  
**SiteInfoBean.java zgD?e?yPO  
*/ |E+.y&0;  
package NetFox; ZRMim6a4X  
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public class SiteInfoBean { B=A!hXNa  
w/@ZPBRo]  
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private String sSiteURL; //Site's URL ERPg TZT  
private String sFilePath; //Saved File's Path #]h X."b2  
private String sFileName; //Saved File's Name APu$t$dmm  
private int nSplitter; //Count of Splited Downloading File -YNpHd/;,  
i(~DhXz*T  
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public SiteInfoBean() k>&cHCS`*  
{//nSplitter的缺省值为5 =.`\V]
 
//default value of nSplitter is 5 7@@g|l]  
this("","","",5); RV~t%Sw^  
} 8
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) h,/Aq  
{ )kep:-wm  
sSiteURL= sURL; ^ZMbJe%L  
sFilePath = sPath; rrL.Y&DTK  
sFileName = sName; [,Ehu<mEK  
this.nSplitter = nSpiltter; LR=Ji7  
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 IuY9Q8  
} |WB-Ng  
ixA.b#!1  
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public String getSSiteURL() AJyNlQ  
{ |z)s9B;:#i  
return sSiteURL; W.3b]zcV  
} x-i1:W9;  
2^[dy>[y0  
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public void setSSiteURL(String value) cWW?@_  
{ 8 a]'G)(ts  
sSiteURL = value; sVx
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} "_/ih1z]
 
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public String getSFilePath() )tG. 9"<  
{ Q`F1t  
return sFilePath; k;\gYb%L  
} *)K\&h<{  
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public void setSFilePath(String value) >YI Vi4''  
{ !Cgj >=  
sFilePath = value; um%_kX  
}
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6Vnq|;W3Zv  
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public String getSFileName() .B]l@E-u  
{ biHacm  
return sFileName; }Xj25` x  
} 1.14tS-}[4  
+/[M Ex=   
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public void setSFileName(String value) Zv!`R($  
{ zRna=h!  
sFileName = value; ?/YABY}L  
} cWAw-E5  
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public int getNSplitter() ,l~<|\4,wv  
{ |aDBp  
return nSplitter; ~N!HxQ  
}
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;VE y{%nF  
>Y>R1b%  
public void setNSplitter(int nCount) 811>dVq3/  
{ Et3I(X3  
nSplitter = nCount; d?7?tL2  
} UDEGQ^)Xz|  
} t@!n?j I  
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/* Y(Oh7VwY*P  
**Utility.java n#+EG3  
*/ 
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package NetFox; ,4'gj0  
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public class Utility { `n$Ak5f  
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public Utility() AERJ]$\  
{ IQJ"B6U)  

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} t^'nh 1=  
,)`_?^\$f  
//线程睡眠 z>PVv)X  
public static void sleep(int nSecond) @6UtnX'd  
{ Um+_S@h  
try{ DZ|*hQU>K  
Thread.sleep(nSecond); _r-LX"  
} $!O@Z8B  
catch(Exception e) ?I?G+(bq  
{ pX%:XpC!h  
e.printStackTrace (); n%3!)/$  
} | In{5Ek  
} C&z!="hMhR  
"L2*RX.R  
//日志 jZ.yt+9  
public static void log(String sMsg) _^FC9  
{ S
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System.err.println(sMsg); W'4/cO  
} )M0`dy{1  
5t:Zp\$+`  
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public static void log(int sMsg) == wX.y\.n  
{ \dHqCQ
  
System.err.println(sMsg); t/[lA=0 )2  
} yv-R<c!'  
} ebze_:  
+iC:/CJL  
}T[@G6#  
/* kx&JY9(&#  
**TestMethod.java ins(RWO  
*/ OQumAj  
package NetFox; eu5te0{G  
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h@`Rk   
public class TestMethod { O=A R`r#u  
g}%ODa !H  
{($bzT7c  
public TestMethod() (m3hD)!+y  
{ ///xx/weblogic60b2_win.exe ]+:yfDtZd  
try{
F>\,`wP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); StJb-K/_cL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Bj7*2}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); XH%pV  
fileFetch.start(); 65aYH4"  
} Ke4oLF2
 
catch(Exception e){e.printStackTrace ();} xVPSL#>
 
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} Vq3NjN!+5  
<.)=CK  
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public static void main(String[] args) Fu.aV876\f  
{ &6\&Mcm
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new TestMethod(); [R4#bl  
} yepRJ%mp  
} NAo.79  
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