http断点续传简单实现（java)

/* <Cn-MOoM  
**SiteFileFetch.java PL%_V ?z  
*/ BEifUgCh  
package NetFox; z/6eP`jj  
import java.io.*; O6lj^  
import java.net.*; DoNbCVZ  
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public class SiteFileFetch extends Thread { vezX/xD?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean m~#98ZJ^  
long[] nStartPos; //开始位置 NR^z!+oSR  
long[] nEndPos; //结束位置 T+N%KRl  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 V 7%rKK  
long nFileLength; //文件长度 97'*Xq  
boolean bFirst = true; //是否第一次取文件 V= !!;KR0  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 4~DFtWbf  
DataOutputStream output; //输出到文件的输出流 h
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） b":cj:mxL  
public SiteFileFetch(SiteInfoBean bean) throws IOException YM/GSSq  
{ Rb|\!  
siteInfoBean = bean; Th'6z#h:U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :hCp@{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); OAR#* ~q  
if(tmpFile.exists ()) 7p@qzE  
{ /wH]OD{  
bFirst = false; iK= {pd  
read_nPos(); 3dQV5E.  
} I[@}+p0  
else N[z7<$$  
{ / ~w\Npf0  
nStartPos = new long[bean.getNSplitter()]; 5e6]v2 k  
nEndPos = new long[bean.getNSplitter()]; IF$f^$  
} $IUT5Gia`  
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} b P4R  
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public void run() 1^b-J0  
{ _Cj u C`7  
//获得文件长度 AQQeLdTq  
//分割文件 s(r(! FZ  
//实例FileSplitterFetch ]fnc.^{  
//启动FileSplitterFetch线程 o!gl :izb  
//等待子线程返回 =K-B I  
try{ BC9rsb  
if(bFirst) <Gr{h>b  
{ Qt+ K,LY  
nFileLength = getFileSize(); -|"mB"Dc  
if(nFileLength == -1) q}U^H  
{ }{J<Wzw  
System.err.println("File Length is not known!"); R<a7TkL4?  
} RxjC sjg  
else if(nFileLength == -2) +F]X  
{ /P Qz$e-!Y  
System.err.println("File is not access!"); (kK6=Mrf  
} #\GWYWkR  
else a=.A/;|0*  
{ "z1\I\ ^  
for(int i=0;i<nStartPos.length;i++) GxuFO5wz  
{ sFT-aLpL@V  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )F8G q,  
} r**u=q%p  
for(int i=0;i<nEndPos.length-1;i++) 4S`2")V  
{ Fi14_{  
nEndPos = nStartPos[i+1]; [x kbzJ  
} #9F=+
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nEndPos[nEndPos.length-1] = nFileLength; j[.R|I|  
} >MauuL,.j  
} ts<5%{M(  
CC;T[b&  
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//启动子线程 C1:efa<wV  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Cb%?s  
for(int i=0;i<nStartPos.length;i++) oe=^CeW"  
{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _{_ybXG|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), RLu y;z  
nStartPos,nEndPos,i); [nZ3}o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pd?3_yU  
fileSplitterFetch.start(); BA4qQCS;5  
} }S\\"SBC  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _?x*F?5=
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); b
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m-xSF]q=<  
nEndPos = " + nFileLength); PO%Z.ol9  
// fileSplitterFetch[nPos.length-1].start(); ,edX;`#  
)hGRq'WA=  
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//等待子线程结束 F4xYfbwY"]  
//int count = 0; R^.E";/h  
//是否结束while循环 k|(uIU* ]  
boolean breakWhile = false; F*_g3K!!  
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while(!bStop) K;a]
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{ *e&Op
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write_nPos(); &U^6N+l9  
Utility.sleep(500); rvgArFf}]  
breakWhile = true; ]?whx&+  
9tDo5 29  
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for(int i=0;i<nStartPos.length;i++) OSY$qL2  
{ 'H+H4(  
if(!fileSplitterFetch.bDownOver) _WO*N9Iz  
{ ..`J-k  
breakWhile = false; hK5BOq!y  
break; t
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} se(ZiyHp  
} D[yOFJ~p)  
if(breakWhile) j qfxQ
  
break; .Zv@iL5  
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//count++; 00X~/'!
 
//if(count>4) Wnm?a!j5  
// siteStop(); UIPi<_Xa  
} owM3Gz%?UA  
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}S
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System.err.println("文件下载结束！"); scZdDbL6+  
} N/IDj2C4  
catch(Exception e){e.printStackTrace ();} XUTI0  
} CT(VV6I\  
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b9b384Q1O  
//获得文件长度 do@`(f3g  
public long getFileSize() fG_.&!P  
{ hfw$820y[  
int nFileLength = -1; \Jq$!foYx  
try{ ^x8*]Sz#x  
URL url = new URL(siteInfoBean.getSSiteURL()); }q7rR:g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;;#28nV  
httpConnection.setRequestProperty("User-Agent","NetFox"); //
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int responseCode=httpConnection.getResponseCode(); /Z`("X?_Kf  
if(responseCode>=400) E_k<EQ%r  
{ LE#ko2#ke  
processErrorCode(responseCode); &Z3g$R 9  
return -2; //-2 represent access is error 6a$=m3ic  
} x$ z9:'U  
k@vN_U
n  
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String sHeader; ,rkY1w-  
- "`5r6  
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for(int i=1;;i++) $<'i+kK  
{ LE$_qX`L  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); QlT{8uw)  
//Utility.log(in.readLine()); |-t>_+. J'  
sHeader=httpConnection.getHeaderFieldKey(i); 1o5n1 A  
if(sHeader!=null) hr9rI  
{ qbcaiU`-^"  
if(sHeader.equals("Content-Length")) r: Ij\YQ  
{ 2GB)K?1M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /BeA-\B  
break; 2UqLV^ZY  
} EMK>7 aks  
} B. '&[A  
else "*E06=fiG  
break; YhQ;>Ko  
} =SMI,p&  
} -CePtq`  
catch(IOException e){e.printStackTrace ();} .&Tcds  
catch(Exception e){e.printStackTrace ();} n~`1KC4  
zb<YYJ]  
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Utility.log(nFileLength); `?@7T-v  
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return nFileLength; _OR@
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} l@:|OGD;8  
9Q)9*nHe  
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2  
//保存下载信息（文件指针位置） Y'n+,g  
private void write_nPos() j'xk[bM  
{ F<R+]M:fa  
try{ fSR+~Vy  
output = new DataOutputStream(new FileOutputStream(tmpFile)); x$p_mWC  
output.writeInt(nStartPos.length); /4K ^-  
for(int i=0;i<nStartPos.length;i++) BF >678h  
{ D=ZH? d  
// output.writeLong(nPos); "}/$xOl"  
output.writeLong(fileSplitterFetch.nStartPos); :<Z>?x  
output.writeLong(fileSplitterFetch.nEndPos); :`U@b
6  
} ,e]|[,r#5  
output.close(); YC,s]~[[  
} (tY0/s  
catch(IOException e){e.printStackTrace ();} uB&um*DP  
catch(Exception e){e.printStackTrace ();}  }\ ^J:@  
} |/!3N  
c-s A?q#|  
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//读取保存的下载信息（文件指针位置） ONr}{T%@/  
private void read_nPos() 8Qm%T7]UFb  
{ k+nfW]UNF  
try{ ?7?hDw_Nk  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); IhRWa|{I  
int nCount = input.readInt(); I;u1my
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nStartPos = new long[nCount]; <.d^jgG
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nEndPos = new long[nCount]; xJ=@xfr$  
for(int i=0;i<nStartPos.length;i++) 9|('*  
{ mT:Z!sS  
nStartPos = input.readLong(); "~:AsZ"7  
nEndPos = input.readLong(); <4{Jm8zJ  
} uC2-T5n'  
input.close(); O%hmGW4  
} Qf=+%-$Y  
catch(IOException e){e.printStackTrace ();} S!Z2aFj  
catch(Exception e){e.printStackTrace ();} ^*-6PV#Z  
} 6!&DH#M  
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cJ^:b4j  
private void processErrorCode(int nErrorCode) PP1?UT=]  
{ * |dz.Tr  
System.err.println("Error Code : " + nErrorCode); j*7#1<T
 
} -9f+O^x  
BNj@~uC{  
4ju=5D];  
//停止文件下载 o$Jop"To  
public void siteStop() C*C;n4AT  
{ Of@LEEh6  
bStop = true; \x(ILk|'c  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); ()\=(n!J  
v4
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} &xgKHbg  
} r9\7I7z  
//负责部分文件的抓取 _`Lv@T.  
**FileSplitterFetch.java 16cc9%   
*/ Qo%IZw$l  
package NetFox; XCAy _fL<B  
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import java.io.*; :U{$G( <  
import java.net.*; GJeP~   
p#QR^|7"  
#'qDNY@w}  
public class FileSplitterFetch extends Thread { B)v|A  
`<oNEr+#  
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String sURL; //File URL (H[.\O-`  
long nStartPos; //File Snippet Start Position /%F}vW(!  
long nEndPos; //File Snippet End Position p)k5Uh"  
int nThreadID; //Thread's ID 9-
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boolean bDownOver = false; //Downing is over e'y$X;nIv  
boolean bStop = false; //Stop identical *mVQN1  
FileAccessI fileAccessI = null; //File Access interface J]-z7<j']  
4S7#B  
aS $ J `  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~'.SmXZs  
{ cxig<W  
this.sURL = sURL; EjF2mkA*  
this.nStartPos = nStart; Uv|?@zy#  
this.nEndPos = nEnd; <0h,{28  
nThreadID = id; {^jRV@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 FpYeuH%  
} JjC& io  
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public void run() ^VOA69n>$  
{ -TT{4\%s  
while(nStartPos < nEndPos && !bStop) YLU.]UC  
{ . l>.  
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try{ /hv2=A  
URL url = new URL(sURL); .
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O,_k.EH  
httpConnection.setRequestProperty("User-Agent","NetFox"); oa"_5kn,  
String sProperty = "bytes="+nStartPos+"-"; \&,{N_G#L.  
httpConnection.setRequestProperty("RANGE",sProperty); 12TX_0  
Utility.log(sProperty); }
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InputStream input = httpConnection.getInputStream(); %Mxc"% w  
//logResponseHead(httpConnection); m2x=Qv][@c  
p`=v$_]?(  
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byte[] b = new byte[1024]; &VdKL2  
int nRead; d>1cKmH!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) IA3m.Vxj ^  
{ M/5+AsT  
nStartPos += fileAccessI.write(b,0,nRead); }J0HEpn4  
//if(nThreadID == 1) @p2XaqZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NxGSs_7  
} GS@Zc2JPF  
6=3;(2u[C"  
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Utility.log("Thread " + nThreadID + " is over!"); u 2%E(pr  
bDownOver = true; szw|`S>o  
//nPos = fileAccessI.write (b,0,nRead); ph~d%/^jI  
} 3D
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catch(Exception e){e.printStackTrace ();} 4SNDKFw  
} 3:mZ1+  
} /DGEI&}&:u  
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Uip-qWI  
//打印回应的头信息 ]z#9
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public void logResponseHead(HttpURLConnection con) "wj~KbT
}&  
{ H9Dw#.em  
for(int i=1;;i++) CYn56eRK  
{ 1F]jy  
String header=con.getHeaderFieldKey(i); 4V7=VZ,@3  
if(header!=null) kVY0 E  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *Kmo1>^  
Utility.log(header+" : "+con.getHeaderField(header)); tpj6AMO/`d  
else ;4Wz0suf  
break; v"8i2+j  
} EHF dQ0gIa  
} 0o]T6
  
,: Z7P@  
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public void splitterStop() =
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{ ohlCuH3  
bStop = true; t+t
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} qL2Sv(A Z!  
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} |
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/* 6|B;C  
**FileAccess.java J}Ji /  
*//文件访问(定位，写) Rd|M)  
package NetFox; G"|c_qX  
import java.io.*; -40s  

::
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l % 0c{E~  
public class FileAccessI implements Serializable{ 0kxe5*-|  
iM +p{/bN  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #%{x*y:Ms  
RandomAccessFile oSavedFile; 01">
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long nPos; Gr|IM,5P4  
30<3DA_P  
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public FileAccessI() throws IOException H|I.h{:  
{ n<3{QqF  
this("",0); +Cs.v.GA5  
} >goG\y  
9ohO-t$XkY  
ot; ]?M  
public FileAccessI(String sName,long nPos) throws IOException SS7C|*-
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{ m*rw?nLZ  
oSavedFile = new RandomAccessFile(sName,"rw"); a(IZ2Zmr  
this.nPos = nPos; m.&"D> \t  
oSavedFile.seek(nPos); 2bt).gGm  
} +O?`uV  
IcUE=J  
(Nn)_caVb  
public synchronized int write(byte[] b,int nStart,int nLen) <qjolMO`  
{ '~n=<Y  
int n = -1; 8ps1Q2|  
try{ >d<tcaB  
oSavedFile.write(b,nStart,nLen); >fx/TSql:J  
n = nLen; 9HG"}CGZP  
} nV>=n,+s"  
catch(IOException e) 0ra+MQBg  
{ I7?s+vyds  
e.printStackTrace (); s&D>'J  
} |l673FcJ  
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return n; a8
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} K?gO]T{6  
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} Igb%bO_  
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Dy^A??A[E}  
/* U{ZKxE  
**SiteInfoBean.java }ZkGH}K_}  
*/ Hr!%L*h?  
package NetFox; 5Tiap8x+<  
0khAi|PY  
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public class SiteInfoBean { uYMH5Om+i  
=aCd,4B}  
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private String sSiteURL; //Site's URL an,JV0  
private String sFilePath; //Saved File's Path +{[E Ow  
private String sFileName; //Saved File's Name
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private int nSplitter; //Count of Splited Downloading File c'uDK>  
 R7ExMJw  
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public SiteInfoBean() eJ_$Etc  
{//nSplitter的缺省值为5 Mk|*=#e;  
//default value of nSplitter is 5 yCZ[z A  
this("","","",5); Vh8RVFi;c  
} ](SqLTB+?  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0uhIJc'2  
{ O+PRP"$g"  
sSiteURL= sURL; ?RU_SCp-  
sFilePath = sPath; ,Laz515  
sFileName = sName; g{^(EZ,  
this.nSplitter = nSpiltter; 4S*7*ak{  
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LhQidvCNJ  
} !y7w~UVs  
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public String getSSiteURL() Xf*}V+&WN  
{ *@[N~:z/  
return sSiteURL; p0@l581  
} e<-^  
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S@6 :H"  
public void setSSiteURL(String value) +YnQOh%v0s  
{ J%lEyU  
sSiteURL = value; C:{&cIFrPe  
} &OP =O*B  
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6d%)MEM  
public String getSFilePath() WkSv@Y,  
{ K?X 6@u|h  
return sFilePath; R\:t 73  
} t2#zQ[~X!  
A=l1_8,`h  
SS"Z>talw  
public void setSFilePath(String value) h f9yK6  
{ N3o kN8d  
sFilePath = value; {14sI*b16  
} CV7%ud]E  
A\T9>z^k  
u\P)x~-TM  
public String getSFileName() y];@ M<<?e  
{ @j+X>TD  
return sFileName; 'Z`fZ5q  
} #PZBh  
kYU!6t1  
TTm  
public void setSFileName(String value) mBWhC<kKs  
{ of>}fJ_p  
sFileName = value; \aB"D=P\ok  
} <n)R?P(or  
]]lM)  
SCKpW#2dP{  
public int getNSplitter() hsHtLH+@  
{ n8 e4`-cY  
return nSplitter; .9KW|(uW  
} Nj|~3 *KO  
z+F:_  
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public void setNSplitter(int nCount) @ )m9#F  
{ jS'hs>Ot  
nSplitter = nCount; hv8j$2m  
} ^9xsbv B0  
} 8`;3`lZ  
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W!4xE  
/* v m)
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**Utility.java HK!Vd_&9,  
*/ Y~uqKb;A  
package NetFox; v9+1[Y";  
$,#,yl ol  
?,Zc{  
public class Utility { {#J1D*?
$"  
"RMvWuNt  
Cd51.Sk(l  
public Utility() ,Z p9,nf  
{ 70{fl 4J5  
|,OTGZgc  
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} B(U0 ~{7a  
}Q%fY&#(bp  
//线程睡眠 8I|2yvhP  
public static void sleep(int nSecond) |q*s)8  
{ )uIHonXU  
try{ c0W4<(  
Thread.sleep(nSecond); N~@VZbS(6  
} fE&wtw{gi  
catch(Exception e) 8GFA}_(^R  
{ ZeYkZzN  
e.printStackTrace (); sKuPV
  
} 
7{:g|dX  
} 5N4[hQrVJ  
w-(^w9_e  
//日志 V;SXa|,  
public static void log(String sMsg) x8wal[6  
{ ,1g*0W^  
System.err.println(sMsg); 0A>Fl*  
}
7+^4v(s  
b1`(f"&l  
4<QSot  
public static void log(int sMsg) lg!{?xM  
{ Pw_[{LL  
System.err.println(sMsg); O`W&`B(*k  
} j2"Y{6c  
} ~'2im[f J  
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1WMwTBHy+  
/* s(
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**TestMethod.java 4yu ^cix(  
*/ Q8
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7  
package NetFox; |xQq+e}l<  
M`kR2NCi  
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public class TestMethod { 6X.lncE@p  
!rMl" Y[  
4$<-3IP,  
public TestMethod() >4}2~;  
{ ///xx/weblogic60b2_win.exe WxFrqUz  
try{ %aeQL;# V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r`T(xJ!)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); * 5Y.9g3)Q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); KU}HVM{  
fileFetch.start(); Kzd`|+?'`M  
} h7H#sL[^  
catch(Exception e){e.printStackTrace ();} 'of5v6:8  
v|v^(P,o  
JV#)?/a$z  
} H21\6 GY  
4f?Y'+>Z,  
#e:*]A'I  
public static void main(String[] args) &i~AXNw  
{ De*Z UN|<  
new TestMethod(); n|oAfJUk,  
} T8i9  
} wGC)gW  
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