http断点续传简单实现（java)

/* ]Ag{#GJ5D  
**SiteFileFetch.java ,N@N4<C]  
*/ &D#B"XI  
package NetFox; Z.3*sp0 yv  
import java.io.*; B5
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import java.net.*; f\c%G=y  
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public class SiteFileFetch extends Thread {
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}`D-]/T8.  
SiteInfoBean siteInfoBean = null; //文件信息Bean +YnQOh%v0s  
long[] nStartPos; //开始位置 % QI6`@Y"  
long[] nEndPos; //结束位置 &OP =O*B  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "<1-9CMl  
long nFileLength; //文件长度 MVZ9x%  
boolean bFirst = true; //是否第一次取文件 [K#pU:lTH  
boolean bStop = false; //停止标志 t2#zQ[~X!  
File tmpFile; //文件下载的临时信息 MB3 N3,yL  
DataOutputStream output; //输出到文件的输出流 ErY-`8U"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 0=c:O  
public SiteFileFetch(SiteInfoBean bean) throws IOException :my@Oxx4@  
{ @j+X>TD  
siteInfoBean = bean; .R{
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #PZBh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZA8FX  
if(tmpFile.exists ()) K])| V  
{ X2to](\%X  
bFirst = false; -`d(>ok  
read_nPos(); zR_yxs'  
} \aB"D=P\ok  
else <n)R?P(or  
{ ]]lM)  
nStartPos = new long[bean.getNSplitter()]; SCKpW#2dP{  
nEndPos = new long[bean.getNSplitter()]; m`H9^w%W  
} gfmaO]  
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} ?&se]\  
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public void run() 5H |<h  
{ 9Li.B1j  
//获得文件长度 _~_6qTv-d  
//分割文件 WDQw)EUl&  
//实例FileSplitterFetch iB
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//启动FileSplitterFetch线程 dxF/]>t  
//等待子线程返回 I<L<xwh1(E  
try{ uc-Go 6W  
if(bFirst) n9r3CLb[  
{ S[L2
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nFileLength = getFileSize(); 7T@"2WYat  
if(nFileLength == -1) R;
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{ /S\y-M9  
System.err.println("File Length is not known!"); E?3$ *t  
} :h)A/k_  
else if(nFileLength == -2) %QKRl5RM-  
{ |q*s)8  
System.err.println("File is not access!"); wO3K2I]>0  
} N~@VZbS(6  
else P g1EE"N@  
{ I0]"o#LjT  
for(int i=0;i<nStartPos.length;i++) PmT,*C`/X  
{ ,Jh('r7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Zfn390_  
} |? l6S
 
for(int i=0;i<nEndPos.length-1;i++) =| M[JPr  
{ xtP=/B/  
nEndPos = nStartPos[i+1]; -(YdK8  
} 1O]27"9  
nEndPos[nEndPos.length-1] = nFileLength; g&6O*vx  
} l\Or.I7n  
} GDj ViAFm  
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//启动子线程 s
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Uv"GG: K_  
for(int i=0;i<nStartPos.length;i++) 6X.lncE@p  
{  >o"3:/3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 34P5[j!h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l TJqWSV=f  
nStartPos,nEndPos,i); Y8yRQzu  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 63?fn~0\  
fileSplitterFetch.start(); bs_"Nn?  
} q$=EUB"C  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v|v^(P,o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 32*FISH^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4f?Y'+>Z,  
nEndPos = " + nFileLength); Rtl;*ZAS  
// fileSplitterFetch[nPos.length-1].start(); Oy!j`  
(mJqI)m8  
p
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//等待子线程结束 G;%Pf9o26  
//int count = 0; B R-(@  
//是否结束while循环 |,ZmRW^2K  
boolean breakWhile = false; y'<juaw  
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while(!bStop) hC.7Z]  
{ <E|K<}W#  
write_nPos(); bTn7$EG  
Utility.sleep(500); L:y} L  
breakWhile = true; syYg, G[  

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for(int i=0;i<nStartPos.length;i++) AE)<ee%\\  
{ m$xyUv1  
if(!fileSplitterFetch.bDownOver) xwj%
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{ 2dr[0
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breakWhile = false; y/m^G=Q6g#  
break; |Aw(v6  
} ,J
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} d/GP.d  
if(breakWhile) J(\"\
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break; *My?l75  
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//count++; _|ucC$*  
//if(count>4) WRJ+l_81  
// siteStop(); ?zKVXK7}0  
} TIV
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+OF(CcA^  
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System.err.println("文件下载结束！"); ?'K}bmdt}.  
} Z3G>DF:$  
catch(Exception e){e.printStackTrace ();} 'A,&9E{%1  
} Lrr^ob
c  
fz W%(.tc\  
2FO.!m  
//获得文件长度 _1c'~;  
public long getFileSize() u!%]?MSc  
{ I'o9.B8%#  
int nFileLength = -1; X9nt;A2TU+  
try{ <GShm~XD2  
URL url = new URL(siteInfoBean.getSSiteURL()); j8@YoD5o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L;xc,"\3  
httpConnection.setRequestProperty("User-Agent","NetFox"); yg "u^*r&  
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int responseCode=httpConnection.getResponseCode(); B7TA:K   
if(responseCode>=400) 2C%{A  
{ f{lg{gA(  
processErrorCode(responseCode); LS?hb)7  
return -2; //-2 represent access is error 2|o6~m<pE  
} Um\Nd#=:  
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String sHeader; 0z."6r  
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for(int i=1;;i++) Q/iaxY#  
{ mqk~Pno|<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b^PYA_k-Xn  
//Utility.log(in.readLine()); uj&^W[s  
sHeader=httpConnection.getHeaderFieldKey(i); A$W,#`E  
if(sHeader!=null) 7I`e5\ u  
{ q+t*3;X.  
if(sHeader.equals("Content-Length")) fk P@e3  
{ `6!l!8 v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &:8a[C2=  
break; 6@!<'l%z  
} 3bpbk  
} [e ;K$  
else gyieSXz[  
break; PP&AF?C  
} E/LR(d_  
} m$A|Sx&sG$  
catch(IOException e){e.printStackTrace ();} f6^H Q1SSt  
catch(Exception e){e.printStackTrace ();} (I,PC*:  
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Utility.log(nFileLength); R3&W.?C T  
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return nFileLength; ]m(Uv8/6  
} (ui"vLk8PP  
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//保存下载信息（文件指针位置） Revc :m1o  
private void write_nPos() M'HmVg4'  
{ hp,bfcM  
try{ _i:yI-jA  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O~-#>a  
output.writeInt(nStartPos.length); j,Qp*b#Qo  
for(int i=0;i<nStartPos.length;i++) 8@Xq ,J  
{ KCDEMs}}zM  
// output.writeLong(nPos); ar=uDb;  
output.writeLong(fileSplitterFetch.nStartPos); [1dlV/  
output.writeLong(fileSplitterFetch.nEndPos); ^{-J Y  
} e0+N1kY  
output.close(); kfg9l?R$I<  
} 5>"$95D  
catch(IOException e){e.printStackTrace ();} =wPl;SDf!  
catch(Exception e){e.printStackTrace ();} U9IN#;W  
} lEANNu  
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//读取保存的下载信息（文件指针位置） A/W0O;*q  
private void read_nPos() M2[;b+W9  
{ 4{X5ZS?CkI  
try{ T
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U=QV^I Qm  
int nCount = input.readInt(); L/"XIMI*Xg  
nStartPos = new long[nCount]; y!."FoQ  
nEndPos = new long[nCount]; Qy*`s  
for(int i=0;i<nStartPos.length;i++) 65\'(99yU  
{ 55Y BO
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nStartPos = input.readLong(); VW I{ wC  
nEndPos = input.readLong(); {XC# -3O  
} My76]\Psh  
input.close(); g03I<<|@  
} =" #O1$  
catch(IOException e){e.printStackTrace ();} \eT0d<  
catch(Exception e){e.printStackTrace ();} 1xar L))  
} )Pakb!0H@t  
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private void processErrorCode(int nErrorCode) {l%Of  
{ GP<A v1  
System.err.println("Error Code : " + nErrorCode); p}.L]Y  
} t)=u}t$  
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//停止文件下载 (q59cAw~X  
public void siteStop() 5(^&0c>P  
{ 1\=)b< y  
bStop = true; eqb8W5h'  
for(int i=0;i<nStartPos.length;i++) 75u/'0~5  
fileSplitterFetch.splitterStop(); y$Sn3_9 V  
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} zp:kdN7!^  
} KaNi'=nW  
//负责部分文件的抓取 3vfm$sx@  
**FileSplitterFetch.java T@GT=1E)  
*/ 1N{}G$'Go  
package NetFox; qT$;ZV #  
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import java.io.*; (/UW}$] h  
import java.net.*; Hm!ffqO_  
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public class FileSplitterFetch extends Thread { N DZ :`D  
1@rI4U@D  
[APwHIS  
String sURL; //File URL HQJ_:x Y  
long nStartPos; //File Snippet Start Position h+<vWo}H  
long nEndPos; //File Snippet End Position 1G$fU zS  
int nThreadID; //Thread's ID ``$Dgj[  
boolean bDownOver = false; //Downing is over E #q gt9  
boolean bStop = false; //Stop identical cVYDO*N2T  
FileAccessI fileAccessI = null; //File Access interface B+[ri&6X\  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException b;G3
&R]  
{ -c|dTZ8D)8  
this.sURL = sURL; F7P?*!dx  
this.nStartPos = nStart; KX D&FDkF  
this.nEndPos = nEnd; M3P
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nThreadID = id; yB0xa%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3tzb@T  
} %Hx8%G!  
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/~~aK2{^X~  
public void run() GOrDDp  
{ v EppkS U1  
while(nStartPos < nEndPos && !bStop) -< D7  
{ FcVQ_6  
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try{ U4)x"s[CP  
URL url = new URL(sURL); 8T<LNC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nb-]fa  
httpConnection.setRequestProperty("User-Agent","NetFox"); %3b;`Oa  
String sProperty = "bytes="+nStartPos+"-"; #gn{X!;-;  
httpConnection.setRequestProperty("RANGE",sProperty); _3@[S F  
Utility.log(sProperty); yvR3
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InputStream input = httpConnection.getInputStream(); ]nPfIBoS  
//logResponseHead(httpConnection); 2E5n07,
 
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byte[] b = new byte[1024]; cxX/ b,  
int nRead; F{*{f =E!B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "#}
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{ Q1f)uwh  
nStartPos += fileAccessI.write(b,0,nRead); (bhMo^3/*  
//if(nThreadID == 1) h0**[LDH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *rKj%Me  
} <"/b 5kc  
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>A&D/kMO  
Utility.log("Thread " + nThreadID + " is over!"); @}9*rWJIE  
bDownOver = true; 3DjlX*  
//nPos = fileAccessI.write (b,0,nRead); WxPu{N  
} *^[m?3"W  
catch(Exception e){e.printStackTrace ();} Yr!@pHy  
} )R %>g-dw  
} B ]*v{?<W  
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ZkWX4?&OMt  
//打印回应的头信息 WAq)1gwN  
public void logResponseHead(HttpURLConnection con) LV}Z[\?  
{ PFR64HK2  
for(int i=1;;i++) OVq(ulwi+  
{ 2/o_,k  
String header=con.getHeaderFieldKey(i); ^*?mb)  
if(header!=null) Oq3aboAt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D[jPz0  
Utility.log(header+" : "+con.getHeaderField(header)); \B/!}Tn;  
else zX]4DLl,  
break; 9}-;OJe  
} (JMk0H3u  
} Gx)U~L$B  
M
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r+%$0eB1^  
public void splitterStop() o|7ztpr  
{ ~K$dQb])  
bStop = true; k2-+3zx  
} P~}Yj@2  
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} N1D{
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/* DhVO}g)2#  
**FileAccess.java q%S^3C&  
*//文件访问(定位，写) aHR+
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package NetFox; evSr?ys  
import java.io.*; ,vDSY N6  
/Fj*sS8  
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public class FileAccessI implements Serializable{ TI5<' U)  
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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 D[p_uDIz  
RandomAccessFile oSavedFile; 0{^ 0>H0  
long nPos; qtR/K=^i  
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public FileAccessI() throws IOException `g}po%k  
{ dDrzO*a\  
this("",0); q<XleC  
} fK/|0@B8  
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3  
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public FileAccessI(String sName,long nPos) throws IOException T)#e=WcP]  
{ b3NEYn  
oSavedFile = new RandomAccessFile(sName,"rw"); uqHI/4  
this.nPos = nPos; 1xTNrLW  
oSavedFile.seek(nPos); L#k`>Qn2  
} ]q`'l_O  
cj;k{Moc  
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public synchronized int write(byte[] b,int nStart,int nLen) w# R0QF  
{ GT 5J`  
int n = -1; b3.}m[]  
try{ 230ijq3YG  
oSavedFile.write(b,nStart,nLen); i'YM9*yN  
n = nLen; +/>XOY|Ie  
} P>nz8NRq  
catch(IOException e) !sVW0JSh  
{ nPR*mbW  
e.printStackTrace (); cI\&&<>SlG  
} Oil~QAd,  
oiRrpS\T.  

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return n; $!goM~pZ  
} ,a34=,  
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} q[TGEgG  
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(zml704dI)  
/* AA XQ+!  
**SiteInfoBean.java WRqpQEY  
*/ ' OXL'_Xl  
package NetFox; sl_f+h0  
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public class SiteInfoBean { K''2
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 yJGnN g  
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private String sSiteURL; //Site's URL @5j3
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private String sFilePath; //Saved File's Path #_kV o3  
private String sFileName; //Saved File's Name '/F% ff  
private int nSplitter; //Count of Splited Downloading File zP8rW5/  
quL+UFuM  
7r{159&=  
public SiteInfoBean() |wM<n  
{//nSplitter的缺省值为5 6<o2 0(?  
//default value of nSplitter is 5 8}Cp(z2  
this("","","",5); kYZj^tR  
} HhB&vi  
"IJ 9vXI  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) av"dJm  
{ +W+o~BE  
sSiteURL= sURL; Hto+
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sFilePath = sPath; Gt$PBlq0  
sFileName = sName; wCt!.<, .  
this.nSplitter = nSpiltter; &PUn,9 Rm  
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} | Zj=E$  
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public String getSSiteURL() ~COd(,ul  
{ >Yx,%a@~R  
return sSiteURL; !bBx'  
} L=&dJpyfT  
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public void setSSiteURL(String value) M7.H;.?  
{ \ZtF,`Z  
sSiteURL = value; {JtfEna  
} /Jc54d  
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cuQAXqXC@  
public String getSFilePath() lZJbQ=K{  
{ ^=arKp,?5  
return sFilePath; M)G|K a  
} &~"e["gF=  
c JOT{  
,HwOMoP7  
public void setSFilePath(String value) !h70<Q^  
{ ozkmZ;  
sFilePath = value; |3C5"R3ZGO  
} W3A9uk6  
h|N!U/(U  
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public String getSFileName() C zxF  
{ yDw#V`Y^M  
return sFileName; qa,i:T(w  
} #@:GLmD%  
j4+kL4M@H  
(%)<jg
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public void setSFileName(String value) <P_B|Y4N/  
{ f,VJfY?#  
sFileName = value; ?sclOOh  
} z4rg.ai  
<|;)iT1VeT  
[&+5E1%L  
public int getNSplitter() S8Yti  
{ EttQ<z_T  
return nSplitter; ;mwU>l,4  
} k? !'OHmBL  
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v4VP7h6uD)  
public void setNSplitter(int nCount) .-}F~FES  
{ lj 2OOU{  
nSplitter = nCount;  K2D, *w  
} 'Omj-o'tn9  
} ~#|Pe1Y  
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:,Mg1Zf  
/* dPmNX-'7  
**Utility.java %<h+_(\
h  
*/ wqAj=1M\  
package NetFox; 7i88i
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public class Utility { ?y2v?h"  
1{?5/F \ +  
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public Utility() }o7"2hht  
{
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} t&H3yV  
-$o4WSd~  
//线程睡眠 5?-@}PL!Y  
public static void sleep(int nSecond) {xCqz0  
{ G'(8/os{  
try{ HBcL1wfS  
Thread.sleep(nSecond); 0l2@3}e  
} fu{.Ir  
catch(Exception e) ~c${?uf   
{ {J]x8
1}*;  
e.printStackTrace (); !c;BOCqa  
} M1J77LfS8  
} a$]i8AeG  
.y>G/8_i  
//日志 o$k9$H>Na  
public static void log(String sMsg) u9D#5NvGs  
{ >_SqM!^v  
System.err.println(sMsg); TgvBy
  
} s'=w/os  
+K7oyZg  
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public static void log(int sMsg) ?(>fB2^  
{ eY8rm  
System.err.println(sMsg); >rid3~  
} ?VR:e7|tU  
} 4x2,X`pe3  
P:fcbfH+  
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/* hv#|dI=kZR  
**TestMethod.java HB
, k}Q  
*/ G$-[(eu-  
package NetFox; ;CLOZ{  
@aUQy;  
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public class TestMethod { /eY}0q%  
UpS7>c7s  
^(~%'f  
public TestMethod() M&^Iun  
{ ///xx/weblogic60b2_win.exe 1XJLGMW,  
try{ pvYBhTz0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); mH/9J  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z^O_7I<5E  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wOF";0EN  
fileFetch.start(); rLp
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} z65Q"A  
catch(Exception e){e.printStackTrace ();} vY2^*3\<D  
m.w.h^f$&  
U$7]
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} ?V' zG&n@  
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public static void main(String[] args) }N0v_Nas;v  
{ J3c8WS{:  
new TestMethod(); Zce/&  
} l'twy$V4|~  
} a
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