http断点续传简单实现（java)

/* !$5.\D  
**SiteFileFetch.java 'k(aZ"  
*/ XDcA&cM}p  
package NetFox; EAi!"NJ  
import java.io.*; tWN hFQ'  
import java.net.*; $wx)/t<  
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public class SiteFileFetch extends Thread { q=(.N>%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ;&v~tD7  
long[] nStartPos; //开始位置 ri?>@i-9=  
long[] nEndPos; //结束位置 uy^vQ/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "ZU CYYre  
long nFileLength; //文件长度 _yJAn\  
boolean bFirst = true; //是否第一次取文件 R#0Z  
boolean bStop = false; //停止标志 b9gezXAcd  
File tmpFile; //文件下载的临时信息 g(Dr/D  
DataOutputStream output; //输出到文件的输出流 ^~Dmb2h  
5$w`m3>i(  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） E |BE(F;K  
public SiteFileFetch(SiteInfoBean bean) throws IOException NHjZ`=Js  
{ C/L+gU&  
siteInfoBean = bean; 7xr@$-U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w;Jby  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;)nV  
if(tmpFile.exists ()) ~xSAR;8  
{ NiCB.a  
bFirst = false; !?u{2D  
read_nPos(); ~gAp`Q  
} ;mw$(ZKa#  
else
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{
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nStartPos = new long[bean.getNSplitter()]; <B%s9Zy  
nEndPos = new long[bean.getNSplitter()]; =Pu;wx9  
} xOAA1#  
~$\9T.tre2  
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} q;<=MO/  
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public void run() vm y?8E6+  
{ bb]r  
//获得文件长度 6bXR?0$*M.  
//分割文件 ToVi;  
//实例FileSplitterFetch ;&N=t64"  
//启动FileSplitterFetch线程 vL,:Yn@b  
//等待子线程返回 WFTXSHcG  
try{ yaD_c;  
if(bFirst) X/l{E4Ex  
{ 3r]:k)J  
nFileLength = getFileSize(); ~Os1ir.  
if(nFileLength == -1) ,4&?`Q  
{ `f~\d.*U  
System.err.println("File Length is not known!"); QxaW
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} g} /efE  
else if(nFileLength == -2) V{y
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{ /P>t3E2c  
System.err.println("File is not access!"); 6?C|pO  
} ?mCino  
else X?8EPCk  
{ qij<XNZU"&  
for(int i=0;i<nStartPos.length;i++) I\DH  
{ XFiP8aX<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &=-ZNWNo  
} qlJzXq{|`  
for(int i=0;i<nEndPos.length-1;i++) (WISf}[l;  
{ *49lM;  
nEndPos = nStartPos[i+1]; [$<\*d/  
} ..5rW0lr  
nEndPos[nEndPos.length-1] = nFileLength; (&)PlIi7  
} 
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} CC8)y
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g]V_)}
 
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//启动子线程 T|o ]8z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;;#_[Zl  
for(int i=0;i<nStartPos.length;i++) nH=8I~jp  
{ @g{FNXY$m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mz'r<v2Tc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BM,]W
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nStartPos,nEndPos,i); %]m/fo4b  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p!OCF]r  
fileSplitterFetch.start(); abW[hp  
} ruKm_j#J  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +=:*[JEK,U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pp2,d`01[L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", MN.h,^b  
nEndPos = " + nFileLength); Ddr.kXIpo  
// fileSplitterFetch[nPos.length-1].start(); 2.>WR
~\  

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t6+c"=P#  
//等待子线程结束 !pqfx93R*  
//int count = 0; XDtMFig  
//是否结束while循环 fK %${   
boolean breakWhile = false; uSl&d  
u3B[1Ae:K  
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while(!bStop) UBm L:Qv  
{ o^!_S5zKe.  
write_nPos(); !'jZ !NFO  
Utility.sleep(500); XjRk1~  
breakWhile = true; Biva{'[m  
RI[=N:C^  
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for(int i=0;i<nStartPos.length;i++) 3!H&bOF  
{ |}-bMQ|  
if(!fileSplitterFetch.bDownOver) _-M27^\vV  
{ S#^2k!(|G  
breakWhile = false; 5OR2\h!XZt  
break; <?&Y_  
} ,Hzz:ce  
} 2lc  
if(breakWhile) L/Ytkag  
break; WCdl 25L#  
o _G,Ph!7  
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//count++; AVnH|31dC~  
//if(count>4) C+m%_6<  
// siteStop(); zFba("E Z  
} %2;Nj; J$  
2I|`j^  
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System.err.println("文件下载结束！"); ]VkM)< +  
} dKk#j@[n"  
catch(Exception e){e.printStackTrace ();} N*w6D:  
} nr{#Krkb  
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//获得文件长度 ].Sz2vI  
public long getFileSize() Z0'&@P$  
{ lA/.4"nN  
int nFileLength = -1; @,:6wKMc  
try{ \`:nmFO(9  
URL url = new URL(siteInfoBean.getSSiteURL()); AbExJ~JV\g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F4*ssx  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4x)etH^o  
1o8C4?T&  
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int responseCode=httpConnection.getResponseCode(); !S3^{l-  
if(responseCode>=400) ixY[ HDPq  
{ /=(PMoZu  
processErrorCode(responseCode); TlEd#XQgf&  
return -2; //-2 represent access is error j%`% DQ  
} 4F`&W*x  
_t/~C*=:=  
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String sHeader; P{K;vEp  
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for(int i=1;;i++) =`KA@~XH4  
{ ;xl0J*r  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); chE}TK  
//Utility.log(in.readLine()); VrIR!9%:  
sHeader=httpConnection.getHeaderFieldKey(i); r6QshCA"  
if(sHeader!=null) Ht"?ajW{  
{ B{lj.S`mB  
if(sHeader.equals("Content-Length")) Bc*FH>E  
{ &|K9qa~)Y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `6:B0-r  
break; {z
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} z}a9%Fb  
} fjd)/Gg  
else }ip3dm  
break; rk-GQ#SKU  
} fpa~~E-  
} :OFs"bC  
catch(IOException e){e.printStackTrace ();} PWBcK_4i%  
catch(Exception e){e.printStackTrace ();} mz|p=[lR|  
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Utility.log(nFileLength); `oU|U!|  
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return nFileLength; ~JS B
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} h5Ee*De  
>i_ #q$o  
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//保存下载信息（文件指针位置） DS1{~_>nFu  
private void write_nPos() ]S
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{ Miz?t*|{[  
try{ ;O
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output = new DataOutputStream(new FileOutputStream(tmpFile)); i*((@:  
output.writeInt(nStartPos.length); #M)+sK$H%f  
for(int i=0;i<nStartPos.length;i++) ]5r@`%9  
{ !T#EkMM  
// output.writeLong(nPos); B#G:aBCM  
output.writeLong(fileSplitterFetch.nStartPos); jx{wOb~oO)  
output.writeLong(fileSplitterFetch.nEndPos); z
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} Y:R*AOx  
output.close(); ni85Ne$  
} IG Ax+3V  
catch(IOException e){e.printStackTrace ();} }a%1$>sj  
catch(Exception e){e.printStackTrace ();} GO)5R,  
} $Jo4n>/  
ph$vP;}  
b
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//读取保存的下载信息（文件指针位置） 1Ror1%Q"?  
private void read_nPos()  i
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{ L|L;<  
try{ Sh2BU3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); akFT 0@9  
int nCount = input.readInt(); 7^7Jh&b)/  
nStartPos = new long[nCount]; s o1hC  
nEndPos = new long[nCount]; hv`I`[/J  
for(int i=0;i<nStartPos.length;i++) 63i&<  
{ 3$_JNF`  
nStartPos = input.readLong(); dmWCNeja.  
nEndPos = input.readLong(); T#<Q[h=  
} (6Ciqf8  
input.close(); I^Dm 3yz  
} N8iLI`  
catch(IOException e){e.printStackTrace ();} "~mY4WVG  
catch(Exception e){e.printStackTrace ();} a4[t3U  
} Q5b9q$L$  
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private void processErrorCode(int nErrorCode) %
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{ |\W53,n9  
System.err.println("Error Code : " + nErrorCode); |R2p^!m  
} pm=m~  
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//停止文件下载 #aQQd8  
public void siteStop() l8khu)\n4R  
{ s"XwO8yhM  
bStop = true; fy$?~Ji&  
for(int i=0;i<nStartPos.length;i++) Eq%f`Qg+1E  
fileSplitterFetch.splitterStop(); ^ L]e]<h(  
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{ V)`6  
} +0?1"2  
} D4\[D8
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//负责部分文件的抓取 fDloL  
**FileSplitterFetch.java 'b0r?A~c=  
*/ <F8e?xy  
package NetFox; W*Si"s2  
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import java.io.*; JA*+F1s
 
import java.net.*; 0'HQ=pP  
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public class FileSplitterFetch extends Thread { $ x:N/mMu`  
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YS#*#!ZMn?  
String sURL; //File URL 5rmU9L  
long nStartPos; //File Snippet Start Position j XH9Pq4  
long nEndPos; //File Snippet End Position 3FtL<7B'.  
int nThreadID; //Thread's ID 
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boolean bDownOver = false; //Downing is over 3vKTCHbk9  
boolean bStop = false; //Stop identical v2I? 5?j  
FileAccessI fileAccessI = null; //File Access interface v<t?t<|J  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~8yh,U  
{ tXqX[Td`0g  
this.sURL = sURL; 2n$Wey[  
this.nStartPos = nStart; peF)U !`D  
this.nEndPos = nEnd; 1yZA_x15:  
nThreadID = id; L$i:~6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 uIbAlE  
} @({=~ W^  
7nPcm;Er  
FZ
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public void run() :EAh%q  
{ 4y#XX[2Wj  
while(nStartPos < nEndPos && !bStop) Xi1|%  
{ `IEA  
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try{ Aj|->Y  
URL url = new URL(sURL); |g.CS$'#Nt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 33EF/k3vW  
httpConnection.setRequestProperty("User-Agent","NetFox"); Av?R6  
String sProperty = "bytes="+nStartPos+"-"; 
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httpConnection.setRequestProperty("RANGE",sProperty); 3LT~-SvL
 
Utility.log(sProperty); w|6/i/X  
q" f65d4c  
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InputStream input = httpConnection.getInputStream(); pY@QR?F\  
//logResponseHead(httpConnection); !6 L!%Oi  
1f<R,>  
#G.eiqh$a  
byte[] b = new byte[1024]; aopZ-^  
int nRead; #-\5O  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) DnFzCJ  
{ +C8O"  
nStartPos += fileAccessI.write(b,0,nRead); ZMb+sUK  
//if(nThreadID == 1)
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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} l'/`2Y1  
YR*gOTD  
(jA5`4>u  
Utility.log("Thread " + nThreadID + " is over!"); L2,2Sn*4i  
bDownOver = true; rHTZM,zM=H  
//nPos = fileAccessI.write (b,0,nRead); !8[T*'LJ-  
} 4`,7tj  
catch(Exception e){e.printStackTrace ();} DtFHh/X  
} L7Hv)  
} v@soS1V!  
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nj'5iiV`]  
//打印回应的头信息 5XUm}D$  
public void logResponseHead(HttpURLConnection con) Ga5*tWj  
{ xy]O8>b  
for(int i=1;;i++) ~t~[@2?WG  
{ hAAh  
String header=con.getHeaderFieldKey(i); *qm|A{FQR  
if(header!=null) CYLab5A  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); P*A+k"DU1  
Utility.log(header+" : "+con.getHeaderField(header)); Yu\$Y0 {]  
else N?ccG\t  
break; R\5,H!V9n  
} &F uPd}F  
} a1~|?PCbY  
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public void splitterStop() o6px1C:  
{ @T~XwJ~  
bStop = true; dazNwn  
} LNWS  
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} eO <N/?t  
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/* s|e.mZk/  
**FileAccess.java ud r\\5  
*//文件访问(定位，写) Yi%lWbr  
package NetFox; (|K+1R  
import java.io.*; x*7A33@i  
"-$}GUK?Z  
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public class FileAccessI implements Serializable{ ~tA ^K  
FC] *^B  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %-blx)Pc  
RandomAccessFile oSavedFile; SG)Fk *1  
long nPos; C '( Y  
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public FileAccessI() throws IOException ZPmqoR[  
{ J:N(U0U  
this("",0); <"5l<E  
} 94+^K=lAX  
}ouGxs+^[  
{&n- @$?  
public FileAccessI(String sName,long nPos) throws IOException zsXgpnlHT  
{ Pp-N2t86#2  
oSavedFile = new RandomAccessFile(sName,"rw"); *~)6
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this.nPos = nPos; T;92M}\  
oSavedFile.seek(nPos); uaF-3  
} N l@G\_  
R%WY!I8C  
}#FV{C]  
public synchronized int write(byte[] b,int nStart,int nLen) wuH*a3(  
{ wHj1+W  
int n = -1; $&as5z8  
try{ ._G,uP$  
oSavedFile.write(b,nStart,nLen); -`PziGl@<  
n = nLen; H%O\4V2s  
} o99ExQ.  
catch(IOException e) <{kPa_`'  
{ _u[tv,  
e.printStackTrace (); 1?Y>Xz  
} )XDBK*!  
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return n; rE+B}O  
} ;qgo=  
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} ~.W]x~X$  
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/* XPX?+W=mv  
**SiteInfoBean.java (SyD)G\rj  
*/ W#F9Qw  
package NetFox; Hh1_z
d|  
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=wh[D$n$~  
public class SiteInfoBean { e_=K0fFz  
eM<N?9s  
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private String sSiteURL; //Site's URL ab2FK
 
private String sFilePath; //Saved File's Path ]bY|>q  
private String sFileName; //Saved File's Name e'K~WNT  
private int nSplitter; //Count of Splited Downloading File MT-T
t  
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]Lub.r  
public SiteInfoBean() }3{eVct#|  
{//nSplitter的缺省值为5 k_7m[o  
//default value of nSplitter is 5 ;7P'>j1?U  
this("","","",5); )dkU4]  
} VmqJMU>.  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u"HGT=Nl  
{ b(0<,r8  
sSiteURL= sURL; .$&^yp  
sFilePath = sPath; -!PJHCLd  
sFileName = sName; j}^w:W76  
this.nSplitter = nSpiltter; o]<Z
3)  
~!$"J}d}<  
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} axnlI*!  
aJ+V]WmA  
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public String getSSiteURL()  gHe:o`  
{ '#+&?6p  
return sSiteURL; 0vv~G\yM  
} 0n
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oPKLr31zt  
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public void setSSiteURL(String value) j9+4},>>CU  
{ B->AY.&j  
sSiteURL = value; fQfn7FaW_\  
} (.4lsKN<  
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public String getSFilePath() v6*0@/L M  
{ aFTWzz  
return sFilePath; Zo
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} ;QBS0x\f@  
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public void setSFilePath(String value) cXb*d|-|N  
{ o!tC{"g  
sFilePath = value; K?uZIDo  
} +x2JC' -H  
CYaN;HV@_  
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public String getSFileName() ?9~^QRLT  
{ u}5CzV`  
return sFileName; {,%&}kd>  
} lb_N"90p  
OH t)z.  
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public void setSFileName(String value) >bW=oTFz  
{ T-] {gc  
sFileName = value; ?Lg(,-:  
} }Fjbj5w0  
1&MCS%UTL  
83vMj$P  
public int getNSplitter() 0i*V?  
{ ;C@mT;hR  
return nSplitter; : B^"V\WE  
} |&#N&t  
q94;x|63  
;%e)t[5  
public void setNSplitter(int nCount) i7#4&r  
{ DPI[~  
nSplitter = nCount; B\Nbt!Ps  
} '7?Y+R@|L  
} ,:t,$A  
vJ&_-CX   
4}H+hk8-  
/* 8US#SI'x  
**Utility.java GLf!i1Z  
*/ -EiTP:A  
package NetFox; J p?XV<3Z  
h.EI(Ev"GN  
H,(vTthd  
public class Utility { #~ x7G  
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k6bct@7  
public Utility() >$D!mraih  
{ /
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jqaX|)8|$  
} m'"r<]pB*4  
Skt-5S#  
//线程睡眠 wMVUTm  
public static void sleep(int nSecond) $?56 i4  
{ n4{%M  
try{ +9Tc.3vQ  
Thread.sleep(nSecond); EVPQe-  
} pCE GZV,d@  
catch(Exception e) B7f<XBU6
>  
{ \GL] I.  
e.printStackTrace (); Jpapl%7v  
} (h0@;@@7hW  
} a`'>VCg  
ozRO:*51  
//日志 +YvF+E  
public static void log(String sMsg) gy.UTAs N  
{ LSC[
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System.err.println(sMsg); Gn2{C%  
} ga +, P  
]d1'5F][H  
95,]86  
public static void log(int sMsg) V#EL
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{ Vgj#-7bdyi  
System.err.println(sMsg); a 8k2*u  
} uRb48Qy2  
} ]yPK}u  
:BPgDLL,  
kPX+n+$  
/* (%B{=w}8  
**TestMethod.java `H! (hMMV  
*/ ?,pwYT0g  
package NetFox; NTu|cX\R  
j=O+U_w  
T1d@=&0
"  
public class TestMethod { v
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sBadiDG~9  
Jx+6Kq(  
public TestMethod() 9Vt ^q%DC  
{ ///xx/weblogic60b2_win.exe 8Yq06o38C  
try{ $\u\4n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pq) =  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); PLz{EQ[cV  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k?fz @H8D(  
fileFetch.start(); j#//U2VdN  
} A]bQUWt2  
catch(Exception e){e.printStackTrace ();} zQ=b|p]|W  
z
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;
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} 4!/QB6   
?,$:~O*w  
d~<$J9%  
public static void main(String[] args) ;KQU% k$  
{ 
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new TestMethod(); C98F?uo%Q  
} )]fiyXA  
} -YQh F;/  
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