http断点续传简单实现（java)

/* S +73 /Vs  
**SiteFileFetch.java z;YX2G/{  
*/ 2j>C4Ck  
package NetFox;
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import java.io.*; |~D~#Nz  
import java.net.*; ]%Whtj.,x7  
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public class SiteFileFetch extends Thread { 2I4G=jM[  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X~; *zYd5  
long[] nStartPos; //开始位置 {2|sk9?W  
long[] nEndPos; //结束位置 5=MM^$QG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /KJWo0zo  
long nFileLength; //文件长度 Tc;BE  
boolean bFirst = true; //是否第一次取文件 9fSX=PVRmQ  
boolean bStop = false; //停止标志 uTrGb:^  
File tmpFile; //文件下载的临时信息 Tkf4`Gxd  
DataOutputStream output; //输出到文件的输出流 %%O_:@9x,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?0E-Lac=  
public SiteFileFetch(SiteInfoBean bean) throws IOException #>$w9}gFi  
{ =U~\iJ  
siteInfoBean = bean; vs.}Bou]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); LrV4^{9(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qp1rP#  
if(tmpFile.exists ()) LTD;  
{ <8Q?kj  
bFirst = false; !%C&hH\  
read_nPos(); *UG=dl#F#  
} P}p6{  
else O >&,h^  
{ WgV[,(  
nStartPos = new long[bean.getNSplitter()]; +7)/SQM5  
nEndPos = new long[bean.getNSplitter()]; w\.z-6G  
} <J1$s_^`  
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} BtWm ZaKi  
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public void run() f['pHR%l2$  
{ L@5g#mSl  
//获得文件长度 K* 0]*am|v  
//分割文件 m4T`Tg#P  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 k{$Mlt?&-  
//等待子线程返回 w~9=6|_  
try{ {I_I$x_  
if(bFirst) m`ab5<%Gn  
{ (V~
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nFileLength = getFileSize(); |a Ht6F  
if(nFileLength == -1) Wr;?t!  
{ p>]2o\["  
System.err.println("File Length is not known!"); 9ev"BO  
} d`+cNKf  
else if(nFileLength == -2) MU&P+Wr  
{ F_Mi/pB^`9  
System.err.println("File is not access!"); $y*["~TJ  
} 5/{gY{  
else %g&i.2v  
{ -@_V|C'?  
for(int i=0;i<nStartPos.length;i++) S)\%.~ n  
{ # OQ(oyT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #6<9FY#  
} 9Lxj ]W2^  
for(int i=0;i<nEndPos.length-1;i++) q^w3n2
 
{ NCysYmt  
nEndPos = nStartPos[i+1]; KEj-y+  
} (PCv4:`g  
nEndPos[nEndPos.length-1] = nFileLength; [HhdeLOX  
} U~8 oE_+  
} Z66@@?`  
S}*%l)vfR  
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//启动子线程 ^E8e
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; FPPGf!Eq  
for(int i=0;i<nStartPos.length;i++) nMHs5'_y  
{ FLekyJmw~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ztS'Dp}q<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O8:,XTAN  
nStartPos,nEndPos,i); 6,|)%~VUm  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A5ps|zidI  
fileSplitterFetch.start(); &Qdd\h#  
} xem:#>&r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bP 2IX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); U= PG0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >m{)shBX  
nEndPos = " + nFileLength); 9f4#b8  
// fileSplitterFetch[nPos.length-1].start(); ~?{"H<  
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"8"7AoE  
//等待子线程结束 pJ#R :#P  
//int count = 0; obE_`u l#  
//是否结束while循环 93d ht  
boolean breakWhile = false; B6b {hsO  
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while(!bStop) vx_v/
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{ >p 7e6%  
write_nPos(); K G~fDb  
Utility.sleep(500); { O*maE"  
breakWhile = true; `_'I 9,.a  
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{ L
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for(int i=0;i<nStartPos.length;i++) ZIx,?E+eJ  
{ l~M86 h  
if(!fileSplitterFetch.bDownOver) vxo iPqo  
{ /*lSpsBn  
breakWhile = false; h^5'i}@u  
break; Ui
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} toEmIa~o6  
} 'qhA4W9  
if(breakWhile) }cE,&n  
break; k]"Rg2
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//count++; b&!7(Q[ sT  
//if(count>4) Au,}5=+`P  
// siteStop(); %fpcH  
} S0~F$mP'  
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@"H+QVJ@  
System.err.println("文件下载结束！"); !58-3F%P  
} -<i&`*zG  
catch(Exception e){e.printStackTrace ();} $N=A,S  
} l 49)Cv/  
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//获得文件长度 CBTa9|57  
public long getFileSize() J+LFzl07q  
{ ^6ZA2-f/<8  
int nFileLength = -1; v>$GVCY  
try{ n5%rsNxg  
URL url = new URL(siteInfoBean.getSSiteURL()); eGblQGRS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SN'LUwaMp!  
httpConnection.setRequestProperty("User-Agent","NetFox"); =1%3". "n@  
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int responseCode=httpConnection.getResponseCode(); R)#D{/#FW  
if(responseCode>=400)
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{ H>`?S{J  
processErrorCode(responseCode); }{S W~yW  
return -2; //-2 represent access is error c`y[V6q9  
} 2ZB'WzH.X  
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String sHeader; ]RQQg,|D  
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for(int i=1;;i++) ^c^9kK'
 
{ VzMoWD;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); t}`|\*a  
//Utility.log(in.readLine()); 'UT 4x9&z  
sHeader=httpConnection.getHeaderFieldKey(i); !o&Mw:d  
if(sHeader!=null) `yHV10  
{ ~^IS{
1  
if(sHeader.equals("Content-Length")) /z,sM"d  
{ !w98[BE7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +tOBt("5/  
break; >GgX-SZ%  
} r 06}@7  
} )D@1V=9,  
else BJk\p.BVN  
break; 6A/Nlk.  
} NwuME/C7#  
} $d!Sl a  
catch(IOException e){e.printStackTrace ();} ~c`@uGw  
catch(Exception e){e.printStackTrace ();} ![:S~x1  
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Utility.log(nFileLength); yc4mWB~gyU  
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return nFileLength; z(3mhMJY  
} f 7et  
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//保存下载信息（文件指针位置） MlsF?"H p  
private void write_nPos() 'sY>(D*CQ  
{ ^,b*.6t  
try{ 7vcYI#(2 Y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); JHc|.2Oe  
output.writeInt(nStartPos.length); @ MNL  
for(int i=0;i<nStartPos.length;i++) )-[ 2vhXz  
{ g^^%4Y  
// output.writeLong(nPos); fh )QX  
output.writeLong(fileSplitterFetch.nStartPos); IJo`O  
output.writeLong(fileSplitterFetch.nEndPos); )"jG)c^1*  
} }vx
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output.close(); _ts0@Z_:  
} netKt_  
catch(IOException e){e.printStackTrace ();} _$
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catch(Exception e){e.printStackTrace ();} i?'HVx  
} &m4 \"X@  
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//读取保存的下载信息（文件指针位置） djPr 4Nog  
private void read_nPos() sxO_K^eD  
{ rNqJL_!  
try{ WMZa6cH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =q^o6{d0"  
int nCount = input.readInt(); W2yNEiH  
nStartPos = new long[nCount]; %7O`]ik:  
nEndPos = new long[nCount]; LlRvm/  
for(int i=0;i<nStartPos.length;i++) jY:(Tv3~  
{ ~DPg):cZ  
nStartPos = input.readLong(); {j,bV6X  
nEndPos = input.readLong(); q uv`~qn  
} bI@+Or  
input.close(); ~VU
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} PFG):i-?  
catch(IOException e){e.printStackTrace ();} Z,,Da|edH  
catch(Exception e){e.printStackTrace ();} o]MQ)\r  
} }%y_LcL  
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private void processErrorCode(int nErrorCode) 8S@ ~^D  
{ @+Berb  
System.err.println("Error Code : " + nErrorCode); EFf<|v  
} mh.0% 9`9  
gUL`)t\}*  
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//停止文件下载 X+P& up06  
public void siteStop() T!pWU*aB
 
{ A]BG*  
bStop = true; . ~G>vVb  
for(int i=0;i<nStartPos.length;i++) Zj~tUCc  
fileSplitterFetch.splitterStop(); T {(6*^g<B  
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}
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} %9-).k  
//负责部分文件的抓取 QCa$<~c  
**FileSplitterFetch.java >efYpd#^  
*/ g*- K!X6l  
package NetFox; i<bFF03*S  
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import java.io.*; TxN#3m?G  
import java.net.*; @XDU!<N  
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public class FileSplitterFetch extends Thread { `8xe2
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String sURL; //File URL #R305  
long nStartPos; //File Snippet Start Position 3r+v
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long nEndPos; //File Snippet End Position *FK!^
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int nThreadID; //Thread's ID Z?XE~6aP>  
boolean bDownOver = false; //Downing is over iIcO_ZyA  
boolean bStop = false; //Stop identical "]kaaF$U%  
FileAccessI fileAccessI = null; //File Access interface  Cg}cD.  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException exTpy  
{ eO(VSjo'`  
this.sURL = sURL; 1U@
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this.nStartPos = nStart; +To{Tm-  
this.nEndPos = nEnd; #2_phm'  
nThreadID = id; cpgHF`nt  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Q++lgVh)E  
} {G%`K,T  
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public void run() RQ9fA1YP  
{ JT[|l-\zo  
while(nStartPos < nEndPos && !bStop) '<>pz<c  
{ i?qS8h{  
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try{ *vCJTz  
URL url = new URL(sURL); s7(mNpo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R\A5f\L9  
httpConnection.setRequestProperty("User-Agent","NetFox"); _D$|lk-  
String sProperty = "bytes="+nStartPos+"-"; Ga.a"\F.V  
httpConnection.setRequestProperty("RANGE",sProperty); }4#%0x`w  
Utility.log(sProperty); +7^%fX;3pW  
=MB[v/M59w  
#&1mc_`/  
InputStream input = httpConnection.getInputStream(); ,D+pGxbr   
//logResponseHead(httpConnection); g>/,},jv[x  
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byte[] b = new byte[1024]; Rl.3p<sX  
int nRead; SEIGs_^'\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q;)[~p  
{ 'F5&f9A  
nStartPos += fileAccessI.write(b,0,nRead); 8nt:peJ$+  
//if(nThreadID == 1) #)GL%{Oa  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -+Kx^V#'R  
} +sQ=Uw#e  
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Utility.log("Thread " + nThreadID + " is over!"); [,8@oM#  
bDownOver = true; a7%5Qg9B;  
//nPos = fileAccessI.write (b,0,nRead); nP0|nPWz#  
} O<Ht-TN&  
catch(Exception e){e.printStackTrace ();} ou
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} @4sv(HyDY  
} (05/}PhB`  
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//打印回应的头信息 3-lJ]7OT  
public void logResponseHead(HttpURLConnection con) S'9T>&<Kn  
{ i`FevAx;[m  
for(int i=1;;i++) iNe;h|  
{ ^0pd- n@pn  
String header=con.getHeaderFieldKey(i); VI74{='=  
if(header!=null) :JV=Kt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Owo2DsT t  
Utility.log(header+" : "+con.getHeaderField(header)); t*NZ@)>  
else w;
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break; c/^} =t(  
} W[AX?  
} 8jMw7ti  
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public void splitterStop() PL@hsZty~c  
{ vCb3Ra~L`  
bStop = true; )%-FnW  
} ]p\7
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} I ^?TabL  
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/* (Dlh;Ic r9  
**FileAccess.java po4seW!  
*//文件访问(定位，写) Yev] Lp  
package NetFox; ~4
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import java.io.*; P%8 Gaa=  
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public class FileAccessI implements Serializable{ ['~3"lK^O  
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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 B:\\aOEj  
RandomAccessFile oSavedFile; Pv17wUB  
long nPos; ~pO6C*"  
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public FileAccessI() throws IOException e=<knKc Q  
{ GPONCL8(0  
this("",0); %YkJA:  
} {pH{SRM)B  
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public FileAccessI(String sName,long nPos) throws IOException $5yH(Z[[
 
{ ",!#7h  
oSavedFile = new RandomAccessFile(sName,"rw"); H!
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this.nPos = nPos; x4r8^,K3Zn  
oSavedFile.seek(nPos); ;PCnEs  
} !_ZknZTT  
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public synchronized int write(byte[] b,int nStart,int nLen) ea kj>7\s  
{ )r3}9J  
int n = -1; :hJHjh  
try{ n+QUT   
oSavedFile.write(b,nStart,nLen); Ebw1 %W KC  
n = nLen; ROlef;/A  
} G0oY`WXOB  
catch(IOException e) K1>X%f^  
{ 5\gL+qM0  
e.printStackTrace (); GqMa|8j  
} c7UmR?m  
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return n; gqV66xmJ3  
} *oopdGue  
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} ,n<t':-  
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/* nr7#}pzo  
**SiteInfoBean.java Yv<'QC  
*/ Q&+Jeji  
package NetFox; F*m^AFjs  
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public class SiteInfoBean { 8,B?!%FP  
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private String sSiteURL; //Site's URL zx` %)r  
private String sFilePath; //Saved File's Path 4wYD-MB  
private String sFileName; //Saved File's Name l r80RL'_  
private int nSplitter; //Count of Splited Downloading File .1n=&d|  
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public SiteInfoBean() ).U\,@[A{  
{//nSplitter的缺省值为5 ^j]"!:h  
//default value of nSplitter is 5 Geyy!sr``  
this("","","",5); g_X-.3=2K  
} gZA[Sq
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) s?Lx\?T  
{ s
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sSiteURL= sURL; X$*MxMNs  
sFilePath = sPath; Y-2IAJHS8  
sFileName = sName; {1?94rz  
this.nSplitter = nSpiltter; -55[3=#

 
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} gu?e%]X3  
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public String getSSiteURL() =MR.*m{  
{ MoAie|MKe  
return sSiteURL; jr/  
} #(@!:f1  
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public void setSSiteURL(String value) hcn$uyP  
{ ?^Gi;d5  
sSiteURL = value; ,+w9_Gy2H  
} -e_91WI  
*Bfo"["0.  
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public String getSFilePath() `iHyGfm  
{ 8^IV`P~2M  
return sFilePath; u<L<o2  
} Sg%h}]~   
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KA $jG{yq  
public void setSFilePath(String value) rX7GVg@H  
{ _V2^0CZ  
sFilePath = value; Eep~3U  
}  yqH  
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public String getSFileName() VSx9aVPkC  
{ 5!QT }Um  
return sFileName; yv[3&E?  
} ]& 8c 45c  
~];r{IU  
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public void setSFileName(String value) $-D}y:  
{ Yg/g9$'  
sFileName = value; (rmOv\hG9V  
} }Q2v~eD  
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DCsamOA~  
public int getNSplitter() *S xDwN  
{ awXK9}.  
return nSplitter; +3yG8  
} L@5sY0 M  
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public void setNSplitter(int nCount) reQr=OAez  
{ -F. c<@*E  
nSplitter = nCount; 8Y]% S9.  
} qX[{_$^Q  
} Y/x>wNW  
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nND; lVQSO  
/* Z~0TO-Q  
**Utility.java `uKsFXM  
*/ mEm=SpO[$o  
package NetFox; t[e]AU[}  
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public class Utility { `@q\R-`  
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public Utility() r>e1IG  
{ t$Bu<frQ  
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} tj?%{L  
^w!1QH0:/  
//线程睡眠 _/czH<   
public static void sleep(int nSecond) Y{Ff I+  
{ 9u6VN]divB  
try{ f, '*f:(  
Thread.sleep(nSecond); 5tI#UBha  
} "{S6iH)]8  
catch(Exception e) \#h{bnx  
{ s TVX/Q  
e.printStackTrace (); ew \WV"  
} qeW.
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} csd9[=HW/Q  
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//日志 fikDpR  
public static void log(String sMsg) 4]HW!J  
{ .L9g*q/}  
System.err.println(sMsg); HUAbq }  
} 3(Ns1/;?,  
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=]r2;014  
public static void log(int sMsg) .=)[S5.BVq  
{ o}&{Y2!x  
System.err.println(sMsg); m-qu<4A/U|  
} d8uDSy  
} ]K3bDU~  
2,Aw6h;  
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/* ~ulcLvm:i  
**TestMethod.java Q:j~ kutS|  
*/ i&1rf|  
package NetFox; C B`7KK  
[8<0Q_?,  
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public class TestMethod { '6kD6o_p1  
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public TestMethod() P(s:+  
{ ///xx/weblogic60b2_win.exe [dR#!"6t  
try{ id588
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >=d 5Scix  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !PA><F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); K_AdMXF9  
fileFetch.start(); UlWm). b;v  
} o[1#)&  
catch(Exception e){e.printStackTrace ();} `M*jrkM]x  
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} bSz@@s.  

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public static void main(String[] args) rq^%)tR  
{ obGhO  
new TestMethod(); kdWUz(  
} <$@I*xk[  
} ,N_/J4Us  
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