http断点续传简单实现（java)

/* ]A%3\)r  
**SiteFileFetch.java 8$_{R!x  
*/ J4::.r  
package NetFox; \#: W  
import java.io.*; *eIX"&ba  
import java.net.*; 8p%0d`sX  
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public class SiteFileFetch extends Thread { 6LCtWX  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Eb4NPWo  
long[] nStartPos; //开始位置 !?JZ^/u  
long[] nEndPos; //结束位置 |> STb\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?;~E*kzO&  
long nFileLength; //文件长度 qP#LJPaS  
boolean bFirst = true; //是否第一次取文件 M^:JhX{  
boolean bStop = false; //停止标志 !\R5/-_UU  
File tmpFile; //文件下载的临时信息 F,~BhKkbV  
DataOutputStream output; //输出到文件的输出流 Az:~|P  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zU&Iy_Ke.  
public SiteFileFetch(SiteInfoBean bean) throws IOException qSr]d`7@  
{ giNXXjl  
siteInfoBean = bean; 6I"KomJ9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h#r~2\q4ei  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;O`f+rG~  
if(tmpFile.exists ()) dfdK%/' $(  
{ Ip{R'H
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bFirst = false; :KO&j"[  
read_nPos(); j;`Q82V\  
} Hvk~BP' m  
else /ZV2f3;t  
{ yHw @Z  
nStartPos = new long[bean.getNSplitter()]; m)p|NdTZc8  
nEndPos = new long[bean.getNSplitter()]; D}
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} ZDmL?mC  
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} S2'ai  
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public void run() n<8WjrK  
{ =|E "  
//获得文件长度 &wK:R,~x6  
//分割文件 ik(YJw'i7E  
//实例FileSplitterFetch gW~T{+f  
//启动FileSplitterFetch线程 qK.(wFx  
//等待子线程返回 68u?}8}  
try{ uxTgK'3  
if(bFirst) <7U~0@<Y  
{ b&[".ibN1  
nFileLength = getFileSize(); &!/>B .  
if(nFileLength == -1) Li5&^RAo|J  
{ .|[{$&B  
System.err.println("File Length is not known!"); USyc D`  
} )v;O2z  
else if(nFileLength == -2) n5d8^c!2  
{ `YqtI/-w  
System.err.println("File is not access!"); yk4@@kHW  
} c46-8z$  
else Qa=Y?=Za  
{ 7zw0g~+  
for(int i=0;i<nStartPos.length;i++) /";tkad^  
{ >b2!&dm  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); e1W9"&4>G{  
} y`n?f|nf  
for(int i=0;i<nEndPos.length-1;i++) o:QL%J{[  
{ n%F _3`  
nEndPos = nStartPos[i+1]; ,K,st+s|  
} s>6h]H  
nEndPos[nEndPos.length-1] = nFileLength; jXA/G%:[  
} uluAqDz`  
} I^k&v V  
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06Wqfzceb  
//启动子线程 7e+C5W*9b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0}<blU  
for(int i=0;i<nStartPos.length;i++) Yt#; +*d5  
{ aDRcVA$*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x[{\Aw>$.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), : b`N(]  
nStartPos,nEndPos,i); &q<k0_5Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Nksm&{=6S  
fileSplitterFetch.start(); ]6Iu\,#J  
} >} 2C,8N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ys=} V|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D?_K5a&v,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Qg/FFn^Kg*  
nEndPos = " + nFileLength); l0,VN,$Yl  
// fileSplitterFetch[nPos.length-1].start(); Am*IC?@tq  
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//等待子线程结束 I;'{X_9$a  
//int count = 0; tR>zB
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//是否结束while循环 i24k ]F  
boolean breakWhile = false; W_M#Gi/AL  
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while(!bStop) L/rf5||@  
{ P{A})t7  
write_nPos(); :L@;.s  
Utility.sleep(500); 5{b;wLi$X2  
breakWhile = true; O;RBK&P  
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for(int i=0;i<nStartPos.length;i++) "e"#k}z9  
{ bss2<mqlH  
if(!fileSplitterFetch.bDownOver) 2
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{ fr(Ja;  
breakWhile = false; X?t;uZI^  
break; 8  *f9  
} 5.VPK 338A  
} >ZkL`!:s  
if(breakWhile) Ni>Ns=n  
break;
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//count++; 3/]1m
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//if(count>4) E$ \l57  
// siteStop(); [Ep'm  
} NC~?4F[  
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System.err.println("文件下载结束！"); *xxk70Cb  
} b, a7XANsh  
catch(Exception e){e.printStackTrace ();} 129\H< m  
} 1J9p1_d5  
}=EJM7sM|k  
3;L$&X2  
//获得文件长度 d\>XfS  
public long getFileSize() z"mVE T  
{ \ 86g y/  
int nFileLength = -1; 8:& !F`o  
try{ :dW\Q&iW  
URL url = new URL(siteInfoBean.getSSiteURL()); =,zB|sjn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); PMTrG78p*  
httpConnection.setRequestProperty("User-Agent","NetFox"); Kfb(wW  
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int responseCode=httpConnection.getResponseCode(); wY ItG"+6  
if(responseCode>=400) v K{2  
{ t,D
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processErrorCode(responseCode); H(;@7dh  
return -2; //-2 represent access is error $!wU[/k  
} W<)nC_$  
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String sHeader; 1,=:an  
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for(int i=1;;i++) a%c 
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{ ^^}htg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h^rG5Q  
//Utility.log(in.readLine()); @>(JC]HtR  
sHeader=httpConnection.getHeaderFieldKey(i); kAp#6->(q  
if(sHeader!=null) v CsE|eMP  
{ xKE=$SV(  
if(sHeader.equals("Content-Length")) !B Pm{_C  
{ :2xGfy??  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); O$,
 
break; X[h{g`  
} rrfJs  
} TY%c`Q5  
else g8E5"jpXx3  
break; \LJ!X3TZ  
} @#hQ0F8  
} ~.x#ic  
catch(IOException e){e.printStackTrace ();} `scW.Vem  
catch(Exception e){e.printStackTrace ();} F-ZTy"z  
5)Z=FUupA~  
! x
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Utility.log(nFileLength); 4J[zNB]  
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return nFileLength; Mhn1-ma:  
} M{orw;1Isy  
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j)8$hK/e0.  
//保存下载信息（文件指针位置） ">=Ep+ix  
private void write_nPos() `EgX#  
{ ??e|ec2%  
try{ (&79}IEd  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <EqS ,cO^  
output.writeInt(nStartPos.length); Dn<3#V  
for(int i=0;i<nStartPos.length;i++) )
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{ G?v<-=I  
// output.writeLong(nPos); !D1#3?L  
output.writeLong(fileSplitterFetch.nStartPos); L44|/~  
output.writeLong(fileSplitterFetch.nEndPos); ~6t<`&f  
} 7l-MVn_8  
output.close(); fr`#s\JKw  
} [@/p 8I  
catch(IOException e){e.printStackTrace ();} 0.+Eo.AX4M  
catch(Exception e){e.printStackTrace ();} i?d545. u  
} <v9IK$J  
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//读取保存的下载信息（文件指针位置） U*{0,Ue'  
private void read_nPos() W2-l_{  
{ Pi1LOCq  
try{ G)YmaHeI;[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g]h@U&`~u_  
int nCount = input.readInt(); pvl];w  
nStartPos = new long[nCount]; eXsp0!v  
nEndPos = new long[nCount]; E8PwA.  
for(int i=0;i<nStartPos.length;i++) *MfH\X379  
{ 'wFhfZB1!B  
nStartPos = input.readLong(); ?4wl  
nEndPos = input.readLong(); ]6^S:K_"  
} 4xT /8>v2|  
input.close(); #\N8E-d  
} /Bgqf,N |  
catch(IOException e){e.printStackTrace ();} 0J[B3JO@M  
catch(Exception e){e.printStackTrace ();} oMYFfnoAa  
} A-m IWTa  
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private void processErrorCode(int nErrorCode) e~*tQ4  
{ h3E}Sa(MQ:  
System.err.println("Error Code : " + nErrorCode); ;=@O.iF;H  
}  7Oe$Ou  
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//停止文件下载 ^& *;]S`  
public void siteStop() \c{sG\ >  
{ 9Bpb?  
bStop = true; ?{ \7th37  
for(int i=0;i<nStartPos.length;i++) id+EBVHAd  
fileSplitterFetch.splitterStop(); fup?Mg-  
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} ?`Mk$Y%my  
} |Wck-+}U  
//负责部分文件的抓取 ^GYVRD  
**FileSplitterFetch.java POc<XLZB  
*/ c1i[1x%
  
package NetFox; ?z|Bf@TJ[+  
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import java.io.*; ,>qtnwvlHP  
import java.net.*; L Y4bn)Qf  
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public class FileSplitterFetch extends Thread { r/':^Ex  
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String sURL; //File URL *1-0s*T  
long nStartPos; //File Snippet Start Position HD{u
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long nEndPos; //File Snippet End Position dg*xo9Xi`  
int nThreadID; //Thread's ID EJz!#f~  
boolean bDownOver = false; //Downing is over . WJ  
boolean bStop = false; //Stop identical jR:
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FileAccessI fileAccessI = null; //File Access interface R$IsP,Uw  
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{
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /EQ^-4yr  
{ !"/"Mqs3$  
this.sURL = sURL; 8z|]{XW{  
this.nStartPos = nStart; OcpvY~"Pr  
this.nEndPos = nEnd; -/B*\X
[  
nThreadID = id; &)Zv>P8z`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6^jrv [d  
} ;D-k\kv  
xh<{
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public void run() 1x/R  
{ 8kd):gZKZ  
while(nStartPos < nEndPos && !bStop) Hsov0  
{ (6H7?nv  
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try{ #68$'Rl"o1  
URL url = new URL(sURL); 0S+$l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }9B},  
httpConnection.setRequestProperty("User-Agent","NetFox"); dEkST[Y3  
String sProperty = "bytes="+nStartPos+"-"; Ed;!A(64r  
httpConnection.setRequestProperty("RANGE",sProperty); gyy}-^`F  
Utility.log(sProperty); 9' H\-  
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InputStream input = httpConnection.getInputStream(); A? jaS9 &)  
//logResponseHead(httpConnection); pcOKC0b.  
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byte[] b = new byte[1024]; d6m&nj  
int nRead; 1W0[|Hf2v*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;*nzb!u\\  
{ #@V<{/;49  
nStartPos += fileAccessI.write(b,0,nRead); .2rpQa/h  
//if(nThreadID == 1) ;sUvY*Bcm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yO
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} #jxPh!%9  
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Utility.log("Thread " + nThreadID + " is over!"); v13\y^t  
bDownOver = true; 4u0?[v[Hu  
//nPos = fileAccessI.write (b,0,nRead); 6_rgRo&  
} {fEb>  
catch(Exception e){e.printStackTrace ();} j~+(#|  
} [*C~
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} i-WP#\s  
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|yj0Rv  
//打印回应的头信息 GqP02P'2  
public void logResponseHead(HttpURLConnection con)  fOsvOC  
{ |,TBP@  
for(int i=1;;i++) 48;b  
{ c\szy&W  
String header=con.getHeaderFieldKey(i); RMs8aZCa  
if(header!=null) cj2^wmkB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4}0YLwgJ  
Utility.log(header+" : "+con.getHeaderField(header)); ]H`pM9rC  
else w!d(NA<|0]  
break; !w!k0z]  
} nemC-4}  
} A3q#,%  
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public void splitterStop() #+h#b%8  
{ Mbly-l{|  
bStop = true; D#Mz#\
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} @b5$WKPX  
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t
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} ;3Z?MQe"NQ  
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/* W^;4t3eQf  
**FileAccess.java gHXvmR"  
*//文件访问(定位，写) u Vv%k5  
package NetFox; G_k_qP^:  
import java.io.*; z-]ND  
cs:?Wq ^  
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public class FileAccessI implements Serializable{ o~xGE6A*"  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 J-klpr#  
RandomAccessFile oSavedFile; x],XiSyp  
long nPos; BoARM{m  
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public FileAccessI() throws IOException = ~*Vfx  
{ u<Ch]m+  
this("",0); &I{5f-o*  
} "-IF_Hid  
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public FileAccessI(String sName,long nPos) throws IOException N
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{ j(pe6  
oSavedFile = new RandomAccessFile(sName,"rw");  Lo)T  
this.nPos = nPos; h]Gvt 5  
oSavedFile.seek(nPos); PyQ\O*  
} G ,`]2'(@  
&g8Xjx&zj  
02:`Joy2D  
public synchronized int write(byte[] b,int nStart,int nLen) v(uNqX.BC  
{ @y eAM7  
int n = -1; \^'-=8<*>  
try{ LS-_GslE7\  
oSavedFile.write(b,nStart,nLen); EyV5FWb58  
n = nLen; (2RuQgO  
} B\ZCJaMb  
catch(IOException e) ^%U`|GBZp  
{ +t]Ge >S  
e.printStackTrace (); J
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} +
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return n; fQw=z$  
} lm{4x~y$h  
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} 3n_t^=  
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/* w`/~y   
**SiteInfoBean.java szOa yAS  
*/ g`6I,6G  
package NetFox; .F\[AD 5  
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public class SiteInfoBean { W=n Hi\jLV  
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private String sSiteURL; //Site's URL M pz9}[`3g  
private String sFilePath; //Saved File's Path ZpwFC7LW  
private String sFileName; //Saved File's Name !<h-2YF<M  
private int nSplitter; //Count of Splited Downloading File XWB#7;,R  
_?Ly7*UML  
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public SiteInfoBean() A`I1G9s  
{//nSplitter的缺省值为5 A#F6~QX(.9  
//default value of nSplitter is 5 u3jLe=Y'\  
this("","","",5); !G'wC0  
} btDTC
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O? 7hT!{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _~y-?(46K  
{ tCj\U+;  
sSiteURL= sURL; |uJjO>8]|  
sFilePath = sPath; nbDjoZZ4  
sFileName = sName; IY@N  
this.nSplitter = nSpiltter; ny<D1>{90  
M'NOM>8  
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} P (fWJ
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j}G9+GX~,  
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public String getSSiteURL() ogdgLTi  
{ - C8VDjf9  
return sSiteURL; }C JK9*Z  
} "2"2qZ*h}  
8&7zV:=
  
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public void setSSiteURL(String value) @[TSJi  
{ !]8QOn7=  
sSiteURL = value; DeQZDY //  
}
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public String getSFilePath() &i*e&{L7  
{ B\~(:(OPM]  
return sFilePath; #Xi9O.  
} 0"mr*hyj  
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n  
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public void setSFilePath(String value) T4;gF
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{ 78IY&q:v&0  
sFilePath = value; U6YQ*%mZ_  
} \.=,}sV2Z  
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"~08<+  
public String getSFileName() c$;Cpt@-j  
{ byk9"QeY\  
return sFileName; Se!B,'C%  
} 0.^67'  
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public void setSFileName(String value) MX|@
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{ _u#r;h[  
sFileName = value; 5^
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} WG&WPV/p  
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X/
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public int getNSplitter() ]OC?
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{ O7f"8|=HX  
return nSplitter; *3y_FTh8ra  
} 07vzVsQ
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0)9n${P7d  
public void setNSplitter(int nCount) af=lzKt*  
{ DV!0zzJ  
nSplitter = nCount; <t,lq  
} wf~n>e^e  
} .h
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/* +"VXw2R_e  
**Utility.java ~01t_Xp qc  
*/  [4mIww%  
package NetFox; Ro#O{  
&M#}?@!C  
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public class Utility { $A)[s$  
+GNXV-S  
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public Utility() *zv*T"&ZP  
{ )24 1-b V  
+ $Lc'G+:  
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} MVp+2@)}s  
t28 y=nv  
//线程睡眠 `Oe}OSxnT  
public static void sleep(int nSecond) stq%Eg?  
{ lkQ(?7  
try{ >oyZD^gj  
Thread.sleep(nSecond); W'5c%SI  
} KWn.  
catch(Exception e) :?\Je+iA  
{ s<8|_Dt  
e.printStackTrace (); X7)B)r}AG  
} ['aiNhl
bt  
} @.h;k4TD  
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//日志 .s3y^1C  
public static void log(String sMsg) E~`<n]{G-C  
{ LC0g"{M  
System.err.println(sMsg); ]KQBek#DD  
} ]fU0;jzX  
vk3C&!M<a  
Bv^5L>JZ/  
public static void log(int sMsg) .QDeS|l  
{ P5Pb2|\*
 
System.err.println(sMsg); Y5
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} piAFxS<6  
} v.>95|8  
X>Y>1fI.  
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/* WCg&*  
**TestMethod.java Q&&oP:4~X*  
*/ ^x}k1F3  
package NetFox; B?;P:!/1  
W9jxw4)  
rf =Wq_  
public class TestMethod { !4T7@V`G  
|GP1[Q{  
#M[%JTTn  
public TestMethod() }i9VV+L#1  
{ ///xx/weblogic60b2_win.exe G]gc*\4  
try{ 9@ :QBe3]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F7JF1HfCP  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p

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SiteFileFetch fileFetch = new SiteFileFetch(bean); ZY8:7Q@P>  
fileFetch.start(); o=C'u  
} 4u7^v1/  
catch(Exception e){e.printStackTrace ();} h:<?)g~U  
+.66Ky`|[  
)Vpt.4IBd  
} A_I\6&b4  
q'`LwAU}  
2:;;  
public static void main(String[] args) "?s  
{ "IRF^1 p  
new TestMethod(); T0%l$#6v  
} Mo[yRRS#  
} />V& OX`  
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