http断点续传简单实现（java)

/* 2+e}*&iQpp  
**SiteFileFetch.java ^zQ/mo,Z  
*/ NA~V
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package NetFox; Sy0$z39  
import java.io.*; 9po3m]|zy  
import java.net.*; . QBF`Rz  
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public class SiteFileFetch extends Thread { =,6z4" )  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :gWu9Y|{  
long[] nStartPos; //开始位置 $xPaYf  
long[] nEndPos; //结束位置 H" 3fT0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 NgP&.39U  
long nFileLength; //文件长度 2QyV%wz  
boolean bFirst = true; //是否第一次取文件 Qo{/@  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 vVFy*#I#_[  
DataOutputStream output; //输出到文件的输出流 +l<5#pazx  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <h:x=  
public SiteFileFetch(SiteInfoBean bean) throws IOException P&*2pX:  
{ @emK1iwm  
siteInfoBean = bean; Ezd_`_@R  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J;8IY=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,)Znb=  
if(tmpFile.exists ()) 4\8+9b\9"  
{ 1cpiHZa  
bFirst = false; !ug8SAOaz/  
read_nPos(); :LW4E9O=
H  
} Q7jb'y$ozO  
else h7lDHIQf  
{ "hH.#5j  
nStartPos = new long[bean.getNSplitter()]; l~w2B>i)  
nEndPos = new long[bean.getNSplitter()]; U@uGNMKR  
} ;;6uw\6 O  
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} 3u*4o=4e  
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public void run() R6;=n"Ueb  
{ >4TaP*_  
//获得文件长度 r\'A i6  
//分割文件 nxnv,AZG  
//实例FileSplitterFetch W{6|tx)  
//启动FileSplitterFetch线程 Y5- F@(  
//等待子线程返回 $
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try{ z[L8
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if(bFirst) !Prg_6 `  
{ 0"  
nFileLength = getFileSize(); | *2w5iR  
if(nFileLength == -1) oAODp!_c  
{ ^ *k?pJ5  
System.err.println("File Length is not known!"); cPyE 6\lN  
} 9PXFRxGA  
else if(nFileLength == -2) -*Xa3/kQ  
{ r!_-"~`7E  
System.err.println("File is not access!"); L*xhGoC=  
} ?PeJlp
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else s>7}zU]  
{ i&bA2p3+d  
for(int i=0;i<nStartPos.length;i++) G|!Tj X7s  
{ |"ls\ 7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Yvw(tj5_5  
} 0l)~i''  
for(int i=0;i<nEndPos.length-1;i++) n'n/Tu   
{ 6F!+T=  
nEndPos = nStartPos[i+1]; xpV|\2C  
} a*lh)l<KV  
nEndPos[nEndPos.length-1] = nFileLength; pjKWtY@=X  
} `VA"vwz  
} wh$sn
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//启动子线程 Lb:g4A"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; qeVfE_<  
for(int i=0;i<nStartPos.length;i++) e^6)Zz1\  
{ <wN}X#M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sJL&:!}V>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^oBtfN>4  
nStartPos,nEndPos,i); tqE6>"jD  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JVvs-bK5
 
fileSplitterFetch.start(); AVlhNIr  
} +~m46eI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N)uSG&S:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?uzRhC_)!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ElcjtYu4  
nEndPos = " + nFileLength); )WNzWUfn=z  
// fileSplitterFetch[nPos.length-1].start(); }
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//等待子线程结束 KrgFKRgGj  
//int count = 0; eenH0Ovv  
//是否结束while循环 7Wf/$vRab  
boolean breakWhile = false; ##,a0s^  
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while(!bStop) W9 GxXPA  
{ g
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write_nPos(); >?2M }TV3  
Utility.sleep(500); H%qsjB^  
breakWhile = true; 1g
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for(int i=0;i<nStartPos.length;i++) `uv2H$  
{ ?8npG]L)  
if(!fileSplitterFetch.bDownOver) tU}h~&M  
{ UdT*E: 6  
breakWhile = false; %a>&5V  
break; g1/:Q%R,  
} l%k\JY-  
} jwc
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if(breakWhile) E:UW#S%A f  
break; fiK6@,  
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7  
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//count++; p|X"@kuseO  
//if(count>4) ?AK(|  
// siteStop(); T,,WoPU8t  
} yr)G]K[/  
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System.err.println("文件下载结束！"); y`Wty@  
} <Th6r.#?  
catch(Exception e){e.printStackTrace ();} yZ0-wI  
} I&D5;8  
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//获得文件长度 ePOG}k($/%  
public long getFileSize() 1!xQ=DU"  
{ ,Xu-@br{  
int nFileLength = -1; ne>pOK<vZ  
try{ Nyku4r0  
URL url = new URL(siteInfoBean.getSSiteURL()); (yH'{6g\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )Kc<j!8-[  
httpConnection.setRequestProperty("User-Agent","NetFox"); $SlIr<'*"  
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int responseCode=httpConnection.getResponseCode(); >6ni")Q9  
if(responseCode>=400) D$w6V  
{ v,FU
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processErrorCode(responseCode); 3
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return -2; //-2 represent access is error 3]5^r}  
} Z)I+@2  
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String sHeader; Lu?C-$a C  
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for(int i=1;;i++) hE-h`'ha`  
{ hi_NOx  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _F6OM5F"N  
//Utility.log(in.readLine()); !EvAB+`jLI  
sHeader=httpConnection.getHeaderFieldKey(i); !y\'EW3|G  
if(sHeader!=null) &Qf/>@ l}  
{ A=$04<nP8!  
if(sHeader.equals("Content-Length")) ax"+0L{  
{ ^=GC3%  J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
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break; LK{*sHi$  
} sQYkQ81  
} :tz#v`3o  
else *z5.vtfu!  
break; 3lf=b~Zi
)  
} Zd3S:),&  
} 2Z+Wu3#  
catch(IOException e){e.printStackTrace ();} |6.l7u?d  
catch(Exception e){e.printStackTrace ();} p2hB8zL  
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Utility.log(nFileLength); J4k=A7^N  
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return nFileLength; u}#(.)a:  
} 1vS#K=sb  
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//保存下载信息（文件指针位置） GoJ.&aH $  
private void write_nPos() KI.q@zO6|  
{ /MIe(,>Uh  
try{ QJZK|*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |tKsgj  
output.writeInt(nStartPos.length); Xe3U`P7(  
for(int i=0;i<nStartPos.length;i++) R4[N:~Z$|  
{ G~F b  
// output.writeLong(nPos); B7VH<;Z  
output.writeLong(fileSplitterFetch.nStartPos); .e
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output.writeLong(fileSplitterFetch.nEndPos); ST|x23|O]  
} ^P[e1?SZG  
output.close(); g?c xp+  
} NN%*b yK  
catch(IOException e){e.printStackTrace ();} 4.k0<  
catch(Exception e){e.printStackTrace ();} ?k+xSV  
} .UQzPnK  
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//读取保存的下载信息（文件指针位置） 1jx:;
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private void read_nPos() S.mG?zbw  
{ *^\Ef4Lh  
try{ -z ID x  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A`N,  
int nCount = input.readInt(); pI1-cV,`  
nStartPos = new long[nCount]; ;dkYf24  
nEndPos = new long[nCount]; =-0/k;^  
for(int i=0;i<nStartPos.length;i++) )%`c_FL@N=  
{ WltQ63u  
nStartPos = input.readLong(); xzdf^Ce  
nEndPos = input.readLong(); GF"hx`zyJ  
} {dhXIs  
input.close(); _:ReN_0  
} z{8bvuE  
catch(IOException e){e.printStackTrace ();} KWq+PeB5TS  
catch(Exception e){e.printStackTrace ();} dph{74Dc  
} '3R`lv   
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private void processErrorCode(int nErrorCode) KKb,d0T[  
{ 46}g7skD  
System.err.println("Error Code : " + nErrorCode); .ODU
 
} ]MqMQLG0t  
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//停止文件下载 7!evm;A  
public void siteStop() ntu5{L'8  
{ v3*_9e  
bStop = true; D.r<QO~6B
 
for(int i=0;i<nStartPos.length;i++) 2+RUTOv/d  
fileSplitterFetch.splitterStop(); yjO1 Ol  
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} _jvxc'6  
} A9[ F  
//负责部分文件的抓取 R#s)r  
**FileSplitterFetch.java E7WK (  
*/ n"h`5p5'  
package NetFox; ]>W6 bTK  
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import java.io.*; 3RigzT3  
import java.net.*; 59 h]UX=  
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public class FileSplitterFetch extends Thread { C>]0YO k2  
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String sURL; //File URL ~jWn4 \  
long nStartPos; //File Snippet Start Position @CNi{. RX
 
long nEndPos; //File Snippet End Position #{6{TFx\  
int nThreadID; //Thread's ID l?\jB\,  
boolean bDownOver = false; //Downing is over Ve8=b0&Y#j  
boolean bStop = false; //Stop identical &r[`>B{tP  
FileAccessI fileAccessI = null; //File Access interface R &nPj~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ):P?  
{ # ncRb  
this.sURL = sURL; _H9 MwJ  
this.nStartPos = nStart; Mhm@R@  
this.nEndPos = nEnd; 1]d!~  
nThreadID = id; ,D5
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 9-sw!tKx  
} gx-2v|pZ  
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public void run() 9,c(ys
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{ j9m_jv  
while(nStartPos < nEndPos && !bStop) ~Q*%DRd&Z-  
{ 7( #:GD  
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try{ #./fY;:cj  
URL url = new URL(sURL); Juo^,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c|f<u{'  
httpConnection.setRequestProperty("User-Agent","NetFox"); l\f*
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String sProperty = "bytes="+nStartPos+"-"; B=U 3  
httpConnection.setRequestProperty("RANGE",sProperty); bAdn &  
Utility.log(sProperty); ov|d^)'  
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InputStream input = httpConnection.getInputStream(); r^2p*nr}  
//logResponseHead(httpConnection); I"xo*}  
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byte[] b = new byte[1024]; ;^+\K-O]c  
int nRead; (|F*vP'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '"`IC\N^  
{ c& <Fr[AK  
nStartPos += fileAccessI.write(b,0,nRead); *$#W]bO  
//if(nThreadID == 1) <g-9T-Ky  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }?lrU.@zg  
} []D&bYpv  
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Utility.log("Thread " + nThreadID + " is over!"); 9
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bDownOver = true; ;$HftG>B  
//nPos = fileAccessI.write (b,0,nRead); x-XD.qh7Hr  
} evenq$ H  
catch(Exception e){e.printStackTrace ();} %]\kgRr  
} #+JG(^%B  
} {GvJZ!,RCg  
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//打印回应的头信息 x;w6na  
public void logResponseHead(HttpURLConnection con) CJtcn_.F  
{ .b_)%jd x  
for(int i=1;;i++) A4Rug\p]  
{ #HYr0Tw6`  
String header=con.getHeaderFieldKey(i); Nv$R\'3  
if(header!=null) Id*Ce2B  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); PYQ;``~x  
Utility.log(header+" : "+con.getHeaderField(header));  JR'  
else q~ tz? T_  
break; 88Ey12$  
} 8."]//V  
} xP_cQwm`1  
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public void splitterStop() [<7@{;r  
{ %W'v}p  
bStop = true; #akpXdXs  
} -N6f1>}pE  
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%) /s;Q,  
} phQUD  
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5
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/* -M~8{buxv  
**FileAccess.java 9 *xR6  
*//文件访问(定位，写) 
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package NetFox; R$v[!A+:'  
import java.io.*; XND|h#i8  
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public class FileAccessI implements Serializable{ f< ia(
d  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 w2;eh]k  
RandomAccessFile oSavedFile; ]5mnew  
long nPos; Jlri*q"hE  
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public FileAccessI() throws IOException %fc!2E9|  
{ ng[Ar`  
this("",0); 8G9s<N}5&u  
} H=@}=aPf  
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public FileAccessI(String sName,long nPos) throws IOException 6RG)`bu  
{ iyA'#bE-  
oSavedFile = new RandomAccessFile(sName,"rw"); VQ"hUX8  
this.nPos = nPos; :=}BN  
oSavedFile.seek(nPos); .
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} XQ#;Zs/l  
v;BV@E0}x  
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public synchronized int write(byte[] b,int nStart,int nLen) aL*&r~`&e'  
{ Mh~q//  
int n = -1; lyIl-!|
 
try{ kv]~'Srk  
oSavedFile.write(b,nStart,nLen); Z"Zmo>cV4  
n = nLen; +Um( h-;  
} *e<[SZzYZ  
catch(IOException e) //*fSF
 
{ T{Gj+7bQ~  
e.printStackTrace (); !_"@^?,q  
} DD7h^-x  

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return n; M.Y~1c4f  
} S\LkL]qx  

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} !\"EFVH  
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/* .Fs7z7?Y  
**SiteInfoBean.java  ;ZH3{  
*/ yaD~1"GA'O  
package NetFox; ,C K{F  
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public class SiteInfoBean { 5"^en# ?9  
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private String sSiteURL; //Site's URL *Y,x|F  
private String sFilePath; //Saved File's Path U(a#@K!H  
private String sFileName; //Saved File's Name .+qQYDEw  
private int nSplitter; //Count of Splited Downloading File Fa?~0H/DL  
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public SiteInfoBean() mN~ci 0  
{//nSplitter的缺省值为5 PjZvQ\Z  
//default value of nSplitter is 5 ?<V?wsp  
this("","","",5); b$4"i XSQ  
} XnDUa3  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N2B|SO''  
{ 'U1R\86M  
sSiteURL= sURL; ADS9DiX/  
sFilePath = sPath; _/F7?^j  
sFileName = sName; Y?S!8-z  
this.nSplitter = nSpiltter; %Qc La//  
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} 5Ec6),+&  
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public String getSSiteURL() &{ay=Mj  
{ 5XO;
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return sSiteURL; Q7*SE%H  
} YX=a#%vrl  
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public void setSSiteURL(String value) 4~y(`\0?4  
{ %oq{L]C(rf  
sSiteURL = value; +Fuqchjq  
} M%Ji0v38  
=5Q]m6-SgV  
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public String getSFilePath() yGWxpzmRS  
{ @*OZx9  
return sFilePath; @<&5J7fb  
} L_vISy%\b  
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public void setSFilePath(String value)
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{ q ]M+/sl  
sFilePath = value; i'4B3  
} w,w{/T+B  
j:5=s%S  
:ZTc7}  
public String getSFileName() :axRoRg  
{ xGu r  
return sFileName; |s"nM<ZNZ  
} Nd`%5%'::  
!;0U,!WI  
9 TvV=  
public void setSFileName(String value) -}=i 04^  
{ ,u!*2cWN  
sFileName = value; G;&-\0>W  
} 1KMLG=  
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public int getNSplitter() )\_:{c  
{ v 0 }
@  
return nSplitter; n1JRDw"e$$  
} hn^<;av=  
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public void setNSplitter(int nCount) wp#'nO  
{ 9S-Z&2L  
nSplitter = nCount; TatpXN\  
} >SML"+>  
} TcIcS]w%  
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/* IOb*GT
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**Utility.java n1~o1  
*/ xgpi-l  
package NetFox; 9^,Lc1"M>  
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public class Utility { bLe<G  
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public Utility() &QDW9 Mi  
{ U'8bdsF_  
 /<HRwG\w  
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} WOQP$D9  
Pf|siC^;s~  
//线程睡眠 hCCiD9gz  
public static void sleep(int nSecond) }2(,K[?  
{ JQV%fTHS  
try{ LA@w:Fg  
Thread.sleep(nSecond); yHs-h   
} dQ_!)f&w1  
catch(Exception e) ~V&aUDO>/  
{ F{EnOr`,m=  
e.printStackTrace (); 
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} k%D+Y(WGz8  
} R($KSui  
jqv-D  
//日志 dik:4;  
public static void log(String sMsg) 4"{ooy^Q  
{ 2ggdWg7
z  
System.err.println(sMsg);
^~G8?]w  
} ^SxY IFL  
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public static void log(int sMsg) '@p['#\uI  
{ v'VD0+3[H  
System.err.println(sMsg); LUuZ9$t0J"  
} 6xWe=QGE  
} ANJ$'3tg  
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/* pV20oSJNt  
**TestMethod.java MKy[hT:  
*/ zY,r9<I8_x  
package NetFox; )6+eNsxMlC  
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public class TestMethod { PIH*Rw*GKZ  
Z0o~+Ct$  
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public TestMethod() |_`E1Y}}  
{ ///xx/weblogic60b2_win.exe R$[#+X!  
try{ i|T)p_y(!a  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r.#t63Rb  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z7_m)@%;kk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); JS*m65e  
fileFetch.start(); um4yF*3b9  
} cgm81+[%r  
catch(Exception e){e.printStackTrace ();} gA:5M  
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} r41\r
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pcT:]d[1)  
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public static void main(String[] args) 0TGLM#{  
{ >S'17D  
new TestMethod(); +RnkJ* l  
} %,D<O,N  
} &jsVw)Ue  
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