http断点续传简单实现（java)

/* dp//p)B>  
**SiteFileFetch.java I).^,%>Z)  
*/ V%
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package NetFox; ]mO+<{{4X  
import java.io.*;  jKb=Zkd  
import java.net.*; d9[6
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public class SiteFileFetch extends Thread { VvMU)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean soQv?4  
long[] nStartPos; //开始位置 93Ci$#<y  
long[] nEndPos; //结束位置 qG2\`+v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 E3.W#=o  
long nFileLength; //文件长度 e~2*>5\:  
boolean bFirst = true; //是否第一次取文件 V)?x*R*T)  
boolean bStop = false; //停止标志 #:ED 0</  
File tmpFile; //文件下载的临时信息 m|Q&Lphb8  
DataOutputStream output; //输出到文件的输出流 PE;0 jgsiI  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6q  xUT  
public SiteFileFetch(SiteInfoBean bean) throws IOException z5o9\.y({  
{ xt<, (4u  
siteInfoBean = bean; {7pE9R5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /bNVgK`L5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); L/ICFa.G  
if(tmpFile.exists ()) t-<[._:+  
{ 2Z IpzH/8  
bFirst = false; 8w@W8(3B  
read_nPos(); ! 4^L $  
} %BYlbEx  
else C)3$";$5)  
{ h}B# 'e  
nStartPos = new long[bean.getNSplitter()]; 6 peM4X  
nEndPos = new long[bean.getNSplitter()]; <,]
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} |z<wPJ,;2  
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} xz+`]Q  
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public void run() IDk:jO  
{ TeN1\rA,  
//获得文件长度 Ci#5@Q9#w  
//分割文件 S>ylAU;N  
//实例FileSplitterFetch iDkWW  
//启动FileSplitterFetch线程 `bi_)i6Low  
//等待子线程返回 ~3-YxCn%  
try{ oj4)7{  
if(bFirst) }HQT@&=  
{ ,IVr4#w0=  
nFileLength = getFileSize(); +KwF U  
if(nFileLength == -1) I#6' NZ  
{ oWaIjU0  
System.err.println("File Length is not known!"); 5_tK3Q8?  
} u%IKM\  
else if(nFileLength == -2) |Nd.'|g,  
{ )'I<xx'1  
System.err.println("File is not access!"); PS<t
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} W-ND<=:Up  
else 7!yF5+_d  
{ my\oC^/9  
for(int i=0;i<nStartPos.length;i++) Z FrXw+  
{ Ef*.}gcU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sFz4^Kn  
} yI|?iBc7nC  
for(int i=0;i<nEndPos.length-1;i++) I3[RaZ2z{  
{ OFAqP1o{$  
nEndPos = nStartPos[i+1]; {j=hQL3  
} R^O)fL0_  
nEndPos[nEndPos.length-1] = nFileLength; ?yM/j7Xn  
} m&z%kVsg]  
} U+A(.+d.  
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//启动子线程 Hr,lA(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ZxeE6&#M^w  
for(int i=0;i<nStartPos.length;i++) y2% ^teXk  
{ gl\{QcI8<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d=OO(sf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IEsD=  
nStartPos,nEndPos,i); e=Tc(Mwn  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p
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fileSplitterFetch.start(); wa
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} iU+,Jeu  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /g-X=|?F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); GDQg:MgX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2uR4~XjF  
nEndPos = " + nFileLength); ]~ 8N  
// fileSplitterFetch[nPos.length-1].start(); <.B> LU  
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<W|{)U?p  
//等待子线程结束 kX .1#%Ex  
//int count = 0; "=TTsxyM6P  
//是否结束while循环 $mg h.3z0  
boolean breakWhile = false; m3!MHe~t  
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while(!bStop) <?@46d?C  
{ Uo)<_nG  
write_nPos(); ~map5@Kd  
Utility.sleep(500); nPX'E`ut-V  
breakWhile = true; [&kk  
5+"8q#X$  
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for(int i=0;i<nStartPos.length;i++) LzSusjEW@  
{ :<3;7R'5  
if(!fileSplitterFetch.bDownOver) $zA[5}{ZtQ  
{ q'-l;V|  
breakWhile = false; GIl
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break; f!Nc+  
} ZrT|~$*m`  
} <;Z~ vZ]  
if(breakWhile) MP&4}De  
break; U~@B%Msb L  
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//count++; JM9Q]#'t  
//if(count>4) -@?>nLQb  
// siteStop(); &`y_R'  
} {YLJKu!M  
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System.err.println("文件下载结束！"); TK?N^ly  
} {$=%5  
catch(Exception e){e.printStackTrace ();} BqAwo  
} nE.s  
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//获得文件长度 j`M<M[C*4N  
public long getFileSize() BnY|t2r  
{ (&x\,19U$  
int nFileLength = -1; c`=hK*  
try{ 3/<^R}w\  
URL url = new URL(siteInfoBean.getSSiteURL()); j'b4Sbs-f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5.UgJ/  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?Og;W9i  
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int responseCode=httpConnection.getResponseCode(); PEhLzZX+  
if(responseCode>=400) XYVeHP!  
{ 62E(=l  
processErrorCode(responseCode); itM
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return -2; //-2 represent access is error G2k71{jK  
} 8j+;Xlh  
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String sHeader; ".Z+bi2l  
=v"{EmT[$  
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for(int i=1;;i++) G?
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{ y`Y}P1y*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 01w/,r  
//Utility.log(in.readLine()); c=E.-  
sHeader=httpConnection.getHeaderFieldKey(i); Cagq0-:(p  
if(sHeader!=null) E&v-(0  
{ jH/%Z5iu  
if(sHeader.equals("Content-Length")) LM`#S/h  
{ 0$uS)J\;K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f}d@G/L  
break; (G'ddZAJV  
} ;!Bkk9r"H  
} 8)ol6Mi{  
else l8li@K  
break; @isqFKjph  
} ew~FN  
} c(JO;=,@9  
catch(IOException e){e.printStackTrace ();} 5n#&Hjb*F0  
catch(Exception e){e.printStackTrace ();} D4T+Gk"n  
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Utility.log(nFileLength); Ps-d#~4U;  
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return nFileLength; qA[}\8}
h  
} `buTP?]4.  

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//保存下载信息（文件指针位置） pp_ddk  
private void write_nPos() l)bUHh5[  
{ >H! 2Wflm  
try{ bsVOO9.4-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L2tmo-]nw  
output.writeInt(nStartPos.length); sIM`Q%  
for(int i=0;i<nStartPos.length;i++) XRin~wz|S  
{ b6VAyTa  
// output.writeLong(nPos); 1
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output.writeLong(fileSplitterFetch.nStartPos); }DwXs`M7  
output.writeLong(fileSplitterFetch.nEndPos); Q5ao2-\  
} 4 .qjTR  
output.close(); VW/1[?HG5  
} >
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catch(IOException e){e.printStackTrace ();} IHfqW?  
catch(Exception e){e.printStackTrace ();} AS ul  
} JJO"\^,;~  
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//读取保存的下载信息（文件指针位置） %J'_c|EQM  
private void read_nPos() zE{zX@  
{ -z94>}Z=  
try{ B5S1F4
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Nrh`DyF0D!  
int nCount = input.readInt(); eSf:[^  
nStartPos = new long[nCount]; {^iV<>J  
nEndPos = new long[nCount]; )/w2]d/9  
for(int i=0;i<nStartPos.length;i++) dY^~^<{Lj  
{ MDt4KD+bZ  
nStartPos = input.readLong(); Yzz8:n  
nEndPos = input.readLong(); To95WG7G  
} 2Ev,dWV  
input.close(); g'@+#NMw  
} xDS9gGr  
catch(IOException e){e.printStackTrace ();} =X):Zi   
catch(Exception e){e.printStackTrace ();} %0'f`P6  
} AmFHn  
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private void processErrorCode(int nErrorCode) ;!b(b%  
{ FeJ5^Gh.  
System.err.println("Error Code : " + nErrorCode); s,8
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} !LA#c'  
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//停止文件下载 7tQiKrhp  
public void siteStop() K(Nk|gQ  
{ &/" qOZAs  
bStop = true; Ar_/9@n
 
for(int i=0;i<nStartPos.length;i++) w.jATMJ)F  
fileSplitterFetch.splitterStop(); 'AU!xG6OQ  
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} Z9y:}:j"  
} {zcjTJ=Zt8  
//负责部分文件的抓取 ZBWe,Xvq  
**FileSplitterFetch.java yO)Qg*r  
*/ -_dgd:or  
package NetFox; ;DOz92X
94  
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import java.io.*; '_%Jw:4k  
import java.net.*; 1Ppzch7  
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public class FileSplitterFetch extends Thread { lPQH_+)Z"  
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String sURL; //File URL 6lGL.m'Ra  
long nStartPos; //File Snippet Start Position t+VPX2  
long nEndPos; //File Snippet End Position _e W*  
int nThreadID; //Thread's ID <f%9w]  
boolean bDownOver = false; //Downing is over uo^>95lkv  
boolean bStop = false; //Stop identical )_ y{^kn3^  
FileAccessI fileAccessI = null; //File Access interface VI4d/2e  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException POf \l  
{ YZ}gZQ.A0  
this.sURL = sURL; oT'XcMn  
this.nStartPos = nStart; Jq->DzSmj/  
this.nEndPos = nEnd; w K+2;*bI  
nThreadID = id; uE2Yn`Ha  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ME(!xI//JZ  
} QZY(S*Up  
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public void run() cjL!$OE6  
{ Zo`^pQS  
while(nStartPos < nEndPos && !bStop) )xeVoAg  
{ 7hc(]8eP  
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`u-}E9{  
try{ n\ZFPXP  
URL url = new URL(sURL); &xVWN>bd^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q'N<
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httpConnection.setRequestProperty("User-Agent","NetFox"); j(SQNSFD  
String sProperty = "bytes="+nStartPos+"-"; 6\`,blkX  
httpConnection.setRequestProperty("RANGE",sProperty); c:bB4ch}  
Utility.log(sProperty); (?Yz#Yf  
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InputStream input = httpConnection.getInputStream(); hN.#ui5 $  
//logResponseHead(httpConnection); R#t~i&v/  
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byte[] b = new byte[1024]; &HE8O}<>  
int nRead; REJ}T:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $KiA~l  
{ +$9w[ARN+  
nStartPos += fileAccessI.write(b,0,nRead); LRs{nN.N  
//if(nThreadID == 1) HTC7fS  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'K`)q6m  
} #X)s=Y&5!T  
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$
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Utility.log("Thread " + nThreadID + " is over!"); zUh(b=,  
bDownOver = true; D -jew&B  
//nPos = fileAccessI.write (b,0,nRead); 1ayxE(vMcX  
} mHP1
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catch(Exception e){e.printStackTrace ();} :+YFO.7  
}
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} pyNPdEy  
?vhW`LXNB  
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//打印回应的头信息 5rc<ibGh  
public void logResponseHead(HttpURLConnection con) {BJxRH"&6*  
{ ELm#  
for(int i=1;;i++) hZpFI?lqc\  
{ []@Mk  
String header=con.getHeaderFieldKey(i); Bg3^BOT  
if(header!=null) @=9QV3D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); W&"FejD  
Utility.log(header+" : "+con.getHeaderField(header)); f; 22viE  
else 
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break; NENbr$,G  
} wiutUb Y  
} GVg0)}  
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public void splitterStop() FGZOn5U6'  
{ *33Zt+  
bStop = true; m^ILcp!  
} i^n&K:6  
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=IUTU4!]  
} V'9 k;SF  
6PTD%Rf\  
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/* ,e;(\t:  
**FileAccess.java 3 -5^$-7_  
*//文件访问(定位，写) 67#;.}4a  
package NetFox; 6L2.88 i  
import java.io.*; ^v,^.>P  
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q H+~rj  
public class FileAccessI implements Serializable{ xD~:= ]G  
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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 k`N)-`O7  
RandomAccessFile oSavedFile; ON$u581 y  
long nPos; >FY`xl\m}<  
6l50IWj,T  
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public FileAccessI() throws IOException SnVnC09y  
{ V8c&2rNa  
this("",0); KQEnC`Nz  
} `InS8PLr  
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$FD0MrB_+  
public FileAccessI(String sName,long nPos) throws IOException N[AX29  
{ . [C~a  
oSavedFile = new RandomAccessFile(sName,"rw"); xL mo?Y*  
this.nPos = nPos; fFsA[@5tul  
oSavedFile.seek(nPos); 2"NJt9w  
} ?gTY!;$P  
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public synchronized int write(byte[] b,int nStart,int nLen) 2r1.,1  
{ rHP5;j<]  
int n = -1; chxO*G  
try{ ,l~i|_  
oSavedFile.write(b,nStart,nLen); $oh}!Smt  
n = nLen; {| Tl3  
} D].1X0^hp  
catch(IOException e) w,^!kO0)~8  
{ _PJd1P.k  
e.printStackTrace (); b,s T[!X[  
} %rYd=Ri  
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gi~*1RIel;  
return n; 0kmZO"K#e  
} 'sJYt^  
"/wZtc  
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} AuWEy-q?  
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/* b]@^SN9  
**SiteInfoBean.java INi(G-!g  
*/ /-1[}h%U'  
package NetFox; rIy,gZr.U  
^xFZ;Yf  
8nNRn[oS  
public class SiteInfoBean { W*N^Gp@  
!}<Y^="  
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private String sSiteURL; //Site's URL ,|}Pof=]xk  
private String sFilePath; //Saved File's Path &_G^=Nc,H  
private String sFileName; //Saved File's Name 8
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private int nSplitter; //Count of Splited Downloading File ;jS~0R  
A[^fG_l
4  
?9.SwIxU&  
public SiteInfoBean() KxqJlben  
{//nSplitter的缺省值为5 8eQ 4[wJY  
//default value of nSplitter is 5 <w<&,xM  
this("","","",5); p"3_u;cN  
} ~^ Q`dJL  
!5&% P b  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fpu^  
{ K8f;AK  
sSiteURL= sURL; Wu?4oF  
sFilePath = sPath; oF8#gn_  
sFileName = sName; (@[c;+x  
this.nSplitter = nSpiltter; SBZqO'}7  
LL4yafh  
~}PB&`%7  
} CB:G4VqOT  
?u/RQ 1  
9+_SG/@  
public String getSSiteURL() -ich N/U]s  
{ gWL'Fl}H  
return sSiteURL; $0=f9+@5  
} Z2!O)
8  
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public void setSSiteURL(String value) [AA'Ko  
{ :>+}|
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sSiteURL = value; OLg=kF[[  
} @FU9!  
\ ?sM  
~QQi{92  
public String getSFilePath() /p}^Tpu  
{ kzcl   
return sFilePath; Z]jm.'@z@  
} 5R"iF+p4  
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public void setSFilePath(String value) Bs:INvhYW  
{ f_I6g uDPz  
sFilePath = value; xJlf}LEyF  
} 6
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[Wf%iwB  
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public String getSFileName() !,WO]Ov  
{ gn4+$f~w  
return sFileName; u?,M`w0'  
} .EpcMXT%  
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public void setSFileName(String value) FX}kH]  
{ =K
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sFileName = value; <#H
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} ROq
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}04EM  
public int getNSplitter() }g&A=u_2  
{ sbqAjm}  
return nSplitter; J$"3w,O6+U  
} l/ufu[x!a  
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public void setNSplitter(int nCount) p(vmMWR!  
{ 8725ET t  
nSplitter = nCount; $S Kax#[  
} _3YZz$07  
} jjLx60|{  
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~FCkr&Ky3  
/* \7]0vG  
**Utility.java 0;6
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*/ l4:B(  
package NetFox; tr?U/YG  
e,V @t%  
!W2dMD/  
public class Utility { A~0eJaq+  
lFJDdf2:$C  
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public Utility() (+aU,E
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{ P]cC2L@Vbi  
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} [0>I6Jl  
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//线程睡眠 8=k
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public static void sleep(int nSecond) #X 1 GL  
{ X?f\j"v  
try{ \P~h0zg?  
Thread.sleep(nSecond); D[i?T3i  
} m-u3^\'  
catch(Exception e) :LrB9Cf$n  
{ :[
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e.printStackTrace (); rvEX;8TS  
} j{&*]QTN  
} [[FDt[
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r&rip^40  
//日志 {f1iys'Om  
public static void log(String sMsg) L*(Sh2=_  
{ H;w8[ImK  
System.err.println(sMsg); ?q{HS&k  
} %H/V iC  
u7(<
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public static void log(int sMsg) GUDz>(  
{ ! mb<z^>5  
System.err.println(sMsg); ^jYE4gHM  
} " i!Xiy~  
} cZR9rnZT  
, ;$SRQ.  
y <] x  
/* qe[P'\]L  
**TestMethod.java H3#rFO"C*  
*/ ?Z(xu~^/  
package NetFox; fug Fk  
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7ILb&JQ!%{  
public class TestMethod { [Fk|%;B/~  
2]
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~8 S2BV3@  
public TestMethod() eXA@J[-M:  
{ ///xx/weblogic60b2_win.exe 4ux^K:z  
try{ }kZ)|/]kn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3Z_\.Z1R@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |\BxKwS^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7MZ(tOR  
fileFetch.start(); 328gTP1  
} CpLLsphy  
catch(Exception e){e.printStackTrace ();} ;Z6ngS  

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+wIv|zj9  
} Xte"tf9(C  
}'u0Q6Obj  
q=x1:^rVH  
public static void main(String[] args) ^~`t q+  
{ CNM
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new TestMethod(); p>h&SD?b  
} ;%^T*?t  
} Jp 7m$D%  
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