http断点续传简单实现（java)

/* L1Fn;nR  
**SiteFileFetch.java ;MCv  
*/ dj?.Hc7od  
package NetFox; u-pE ;|  
import java.io.*; A8
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import java.net.*; |>A1J:  
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public class SiteFileFetch extends Thread { v.cB3/$z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean GfJm&'U&  
long[] nStartPos; //开始位置 0X0HDQ  
long[] nEndPos; //结束位置 &EXql']  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 WaN0$66[:  
long nFileLength; //文件长度 ;#3!ZB:}  
boolean bFirst = true; //是否第一次取文件 Uv[:Aj  
boolean bStop = false; //停止标志 6}x^T)R  
File tmpFile; //文件下载的临时信息 `wB(J%w  
DataOutputStream output; //输出到文件的输出流 vjZX8KAiZ  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5xLuuKG  
public SiteFileFetch(SiteInfoBean bean) throws IOException _7]5Q  
{ E7^tU416  
siteInfoBean = bean; idPkJf/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i{T0[\4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /I$g.f/#  
if(tmpFile.exists ()) F]z xx  
{ 8_Y{7;<ey  
bFirst = false; {TzKHnP  
read_nPos(); ]J;^< 4l  
} ;{
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else C n\'sb{  
{ mV`Z]-$$i  
nStartPos = new long[bean.getNSplitter()]; # u^FB  
nEndPos = new long[bean.getNSplitter()]; }.o rfW  
} zL3~,z/o  
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} HHWB_QaL  
;'}1  
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public void run() @w,-T@nAW  
{ I@+dE V`Lf  
//获得文件长度 "]*0)h_  
//分割文件 S=krF yFw  
//实例FileSplitterFetch M
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//启动FileSplitterFetch线程 eO(VSjo'`  
//等待子线程返回 @5acTYQ  
try{ 9!_`HE+(XJ  
if(bFirst) Z\(+a
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{ D gY2:&0  
nFileLength = getFileSize(); ~6
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if(nFileLength == -1) R7Zx
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{
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System.err.println("File Length is not known!"); ,Ztj  
} -7'>Rw  
else if(nFileLength == -2) {{SQL)yJ  
{ '<>pz<c  
System.err.println("File is not access!"); ,U]
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} PM7*@~.  
else HR\yJt  
{ < I8hy$+6  
for(int i=0;i<nStartPos.length;i++) {/XzIOO;b  
{ .FqbX5\p,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !wJ~p:vRdY  
} 2[r#y1ro  
for(int i=0;i<nEndPos.length-1;i++) k U*
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{ 1W$@ V!  
nEndPos = nStartPos[i+1]; 8!b#ez  
} MHI0>QsI  
nEndPos[nEndPos.length-1] = nFileLength; ~BrERUk  
} c/x ^I{b*  
} 6Nj\N oS  
iKLN !QR  
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//启动子线程 (t>BO`,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; FGzB7w#  
for(int i=0;i<nStartPos.length;i++) $MfHA~^  
{ ojT TYR{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~U~
KUL|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rzLpVpTaz  
nStartPos,nEndPos,i); Y71io^td~j  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *S:^3{.m=  
fileSplitterFetch.start(); ;pBSGr9  
} &P&M6v+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Zh{Pzyp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 80![aj}z4G  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -%5*c61  
nEndPos = " + nFileLength); Br`Xw^S  
// fileSplitterFetch[nPos.length-1].start(); &h
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//等待子线程结束 DNLqipUw  
//int count = 0; s34{\/'D+  
//是否结束while循环 pu0IhDMn  
boolean breakWhile = false; 3-lJ]7OT  
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9=ns.r  
while(!bStop) Xb?P'nD  
{ ?`uY*+u  
write_nPos(); {tOu+zy  
Utility.sleep(500); R',Q)<  
breakWhile = true; r[q-O&2&  
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for(int i=0;i<nStartPos.length;i++) !
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{ c/^} =t(  
if(!fileSplitterFetch.bDownOver) #i%it  
{ Kxn/@@z>u  
breakWhile = false; |bQKymS  
break; O B_g:T  
} q}*(rR9/Br  
} jdK~]eld=  
if(breakWhile) )c^Rc9e/  
break; K``MS  
#OqQD6  
plh.-"   
//count++; I ^?TabL  
//if(count>4) Z[)t34EY"  
// siteStop(); $k,Z)2  
} |j^^*z@  
~-.}]N+([  
t:eZ`6o$T\  
System.err.println("文件下载结束！"); I+rHb< P%  
} _<6
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catch(Exception e){e.printStackTrace ();} s+#gH@c  
} IGV@tI  
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[ %cW ?@  
//获得文件长度 s{(aW5$!s  
public long getFileSize() V:fz  
{ =ps3=D  
int nFileLength = -1; yH|[K=?S[  
try{ 9E'fM  
URL url = new URL(siteInfoBean.getSSiteURL()); e=<knKc Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GPONCL8(0  
httpConnection.setRequestProperty("User-Agent","NetFox"); E2 Q[  
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int responseCode=httpConnection.getResponseCode(); 0M7Or)qN  
if(responseCode>=400) $5yH(Z[[
 
{ )e
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processErrorCode(responseCode); H!
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return -2; //-2 represent access is error jVC`38|  
} 5=WzKM  
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String sHeader; cfBq/2I  
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V7[6jWgH  
for(int i=1;;i++) E
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{ 0x7F~%%2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V(I!HT5.W  
//Utility.log(in.readLine()); [=7=zV;}4  
sHeader=httpConnection.getHeaderFieldKey(i); Jr$,w7tQn@  
if(sHeader!=null) PIR#M('  
{ tJ>%Xop  
if(sHeader.equals("Content-Length")) N:?U
A  
{ ]VtVw^ir  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mk(O..)2  
break; 
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} d[E~}Dq3#  
} #?\$*@O  
else N[~{'i  
break; Xb?:dlu3  
} $&&mGD;?K  
} dn(I$K8  
catch(IOException e){e.printStackTrace ();} H=Scrvfx  
catch(Exception e){e.printStackTrace ();} m?'H7cFR  
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Utility.log(nFileLength); 4Vl_vTz{i  
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return nFileLength; I L]uw   
} @32~#0a  
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//保存下载信息（文件指针位置） *j5>2-C &  
private void write_nPos() %:2EoXN"  
{ q.0Evr:  
try{ !~Vo'ykwx'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i[_(0P+Da  
output.writeInt(nStartPos.length); yMaU`z  
for(int i=0;i<nStartPos.length;i++) f++MH]I;  
{ p)6!GdT  
// output.writeLong(nPos); 701a%Jq_2  
output.writeLong(fileSplitterFetch.nStartPos); 1P4cBw%  
output.writeLong(fileSplitterFetch.nEndPos); ).U\,@[A{  
} ^j]"!:h  
output.close(); Geyy!sr``  
} B7PkCS&X  
catch(IOException e){e.printStackTrace ();} \|e>(h!l;  
catch(Exception e){e.printStackTrace ();} 1 aWzd[i  
} $J6Pv   
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//读取保存的下载信息（文件指针位置）
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private void read_nPos() 8T6LD  
{ !dnCrR  
try{ g)0>J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); YnM&t ;TX  
int nCount = input.readInt(); w-iu/|}  
nStartPos = new long[nCount]; X$*MxMNs  
nEndPos = new long[nCount]; Pq\ `0/4_  
for(int i=0;i<nStartPos.length;i++) L\0;)eJ#M  
{ LLyw9y1  
nStartPos = input.readLong(); %+ln_lgD:  
nEndPos = input.readLong(); aa|u*afWQ  
} UWU(6J|Fk  
input.close(); ] V|hDU=t  
} xgDd5`W  
catch(IOException e){e.printStackTrace ();} 7~b=G  
catch(Exception e){e.printStackTrace ();} <P
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} J)7\k$D  
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private void processErrorCode(int nErrorCode) WX"iDz.  
{ #(@!:f1  
System.err.println("Error Code : " + nErrorCode); O
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} |Gp!#D0b
  
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//停止文件下载 *Bfo"["0.  
public void siteStop() cp1-eR_&  
{ f^JiaU4 [  
bStop = true; ),{v  
for(int i=0;i<nStartPos.length;i++) r ^=rs!f@  
fileSplitterFetch.splitterStop(); 7bV(eV  
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} :1*q}R   
} vCvjb\S  
//负责部分文件的抓取 *y+N-uq  
**FileSplitterFetch.java ;X_bDiG$  
*/  yqH  
package NetFox; m:}PVJ-"  
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import java.io.*; \;XDPC j  
import java.net.*; ./]xn  
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public class FileSplitterFetch extends Thread { In[rxT~K}Q  
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String sURL; //File URL Ky0}phGRu  
long nStartPos; //File Snippet Start Position 2xLEB&  
long nEndPos; //File Snippet End Position ^VC/tJ  
int nThreadID; //Thread's ID 45.<eWH$*(  
boolean bDownOver = false; //Downing is over !S.O~Kq  
boolean bStop = false; //Stop identical ]z5kYU&  
FileAccessI fileAccessI = null; //File Access interface 8
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException SND@#?hiO  
{ sLKk1A  
this.sURL = sURL; 2jf73$F  
this.nStartPos = nStart; L<XAvg  
this.nEndPos = nEnd; p< Y-b,&  
nThreadID = id; W [
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 4,,DA2^!  
} QdIx@[+WOq  
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public void run() mjQZ"h0  
{ 6i+<0b}!/  
while(nStartPos < nEndPos && !bStop) a}e GB +  
{ Z~0TO-Q  
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try{ XE
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URL url = new URL(sURL); ~'V&[]nh8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0 k.\o"y  
httpConnection.setRequestProperty("User-Agent","NetFox"); A"e4
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String sProperty = "bytes="+nStartPos+"-"; +>&i]x(b  
httpConnection.setRequestProperty("RANGE",sProperty); YdZ9##IU3  
Utility.log(sProperty); y Nc@K|  

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InputStream input = httpConnection.getInputStream(); t$Bu<frQ  
//logResponseHead(httpConnection); `q9n`h1  
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byte[] b = new byte[1024]; >'lvZt  
int nRead; xfF;u9$;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wBWqibY|  
{ 7|HIl=  
nStartPos += fileAccessI.write(b,0,nRead); vbD""  
//if(nThreadID == 1) _Sg"|g  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gSa!zQN6  
} {#.<hPXn  
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Utility.log("Thread " + nThreadID + " is over!"); qfkdQ/fP  
bDownOver = true; y7t'I.E[+  
//nPos = fileAccessI.write (b,0,nRead); \0W0o5c$  
} GlHP`&;UH  
catch(Exception e){e.printStackTrace ();} +/[L-&,  
} x?UAj8z6  
} *rg
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//打印回应的头信息 )Q 5 x
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public void logResponseHead(HttpURLConnection con) dWx@<(`OC  
{ VA>0Y
  
for(int i=1;;i++) HUAbq }  
{ t~H0Qeb[v=  
String header=con.getHeaderFieldKey(i); '3w%K+eJY  
if(header!=null) YV8PybThc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #bJp)&LO  
Utility.log(header+" : "+con.getHeaderField(header)); \@Gcx}Y8h  
else MK-+[K  
break; !|W.YbS  
} nC%<BatQ  
} hx*4xF  
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public void splitterStop() 
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{ 3RX9LJGX  
bStop = true; TCFr-*x  
} K5rra%a-7  
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} m^\&v0  
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Y_}_)n
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/* 
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**FileAccess.java 9[`c"Pd  
*//文件访问(定位，写) 0~z`>#W,  
package NetFox; ]WzeJ"r {3  
import java.io.*; ^9`|QF  
o[1#)&  
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public class FileAccessI implements Serializable{ jJaMkF;f  
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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`0b$
  
RandomAccessFile oSavedFile;
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long nPos; ek.@ 0c  
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public FileAccessI() throws IOException E]v]fy"  
{ /N({"G'  
this("",0); !g`I*ZE+e  
} w=CzPNRHH!  
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public FileAccessI(String sName,long nPos) throws IOException v`c;1?=,q  
{ h-//v~V)  
oSavedFile = new RandomAccessFile(sName,"rw"); uts>4r>+  
this.nPos = nPos; +0 }_
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oSavedFile.seek(nPos); @( \R@
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} f~*7hv\  
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public synchronized int write(byte[] b,int nStart,int nLen) 8{]nS8i  
{ +~BP~  
int n = -1; 7x=4P|(\}  
try{ 0l4f%'f   
oSavedFile.write(b,nStart,nLen); CPL,QVO9  
n = nLen; &S`g&  
} dF09_nw  
catch(IOException e) i6A9|G$H
 
{ a'`?kBK7`U  
e.printStackTrace (); Ch3MwM5]  
} 9=j)g  
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return n; *7-rm  
} ' tHa5`  
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H] g=( %ok  
} %.D!J",\/K  
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/* xkw=os  
**SiteInfoBean.java dA (n,@{  
*/ z;dRzwL  
package NetFox; -%]1q#C>@  
rQ_]%ies8  
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public class SiteInfoBean { Qclq^|O0  
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private String sSiteURL; //Site's URL RjH68=n  
private String sFilePath; //Saved File's Path t1U+7nM  
private String sFileName; //Saved File's Name K9.Gjw  
private int nSplitter; //Count of Splited Downloading File \K~wsu/?`  
MoQ\~/Z|  
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public SiteInfoBean() F~qZIggD  
{//nSplitter的缺省值为5 J^ewG  
//default value of nSplitter is 5 %k32:qe  
this("","","",5); AD^I1]2f  
} oPF]]Imu  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ef?hkq7X<  
{ 7)Vbp--b#  
sSiteURL= sURL; a;^lOU|L{  
sFilePath = sPath; g`Cv[Pq?at  
sFileName = sName; 0MroHFh9`  
this.nSplitter = nSpiltter; uoOUgNwGg  
;@Fb>lBhX  
4p-"1c$  
} `Fo/RZOW  
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d@1^U9sf  
public String getSSiteURL() 0IdA!.|  
{ H8[A*uYL  
return sSiteURL; oSmETk\  
} jwAYlnQ^EM  
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public void setSSiteURL(String value) r8eJ&-Yi{Z  
{ X[r0$yuE  
sSiteURL = value; ZAU#^bEQB  
} kE
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#=S^i[K/  
public String getSFilePath() T]Ai{@i  
{ 'sH_^{V2  
return sFilePath; S4 Uu/EX6S  
} c`p'5qz  
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public void setSFilePath(String value) A"&<$5Q  
{ (DY[OIHI  
sFilePath = value; Xpn\TD<_I  
} ;5.&TQT  
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public String getSFileName() H!Q72tyo  
{ ZK'46lh  
return sFileName; CX{6  
} o h\$u5  
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public void setSFileName(String value) <7F-WR/2n  
{ dH;2OWM  
sFileName = value; AQ@)'  
} $.,B2}'  
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qf\W,SM  
public int getNSplitter() [bP^RY:  
{ eBnx$  
return nSplitter; tx>7?e8E  
} 6(d6Uwc`  
<A8>To<  
6V]m0{:E  
public void setNSplitter(int nCount) :,aY|2si  
{ zA>X+JH>iw  
nSplitter = nCount; !|xB>d q?  
} t~j6wsx;  
} `3i>e<m~  
<MkvlLu((o  
~Ay)kv;  
/* HrvyI)4{  
**Utility.java }URdoTOvb  
*/ EG3,TuDH8  
package NetFox; <6Gs0\JB  
>h;]rMD!|  
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public class Utility { 4k@n5JNa  
>d p/  
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public Utility() Dk^AnMx%_  
{ dGBjV #bNT  
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} mLZ1u\7W  
G@`F{l  
//线程睡眠 X\P%C  
public static void sleep(int nSecond) -i2rcH  
{ b|Emu!9U  
try{ |_TI/i>?'  
Thread.sleep(nSecond); px K&aY8  
} "nu]3zcd  
catch(Exception e) sb{K%xi%  
{ zG6l8%q'UE  
e.printStackTrace (); !9_(y~g{N  
} "4\  
} 7[;!enO  
{sC Ni  
//日志 mW%8`$rVEO  
public static void log(String sMsg) F6[F~^9D  
{ uW!XzX['  
System.err.println(sMsg); MmjZq  
} e6j1Fa9  
#Z2'Y[@.  
?QT6q]|d0+  
public static void log(int sMsg) J@I>m N1\  
{ N,Ma\D+^t  
System.err.println(sMsg); ErK1j  
} f_S$CFa@  
} 6Bjo9,L  
}OAU5P!rp  
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/* >z\IO  
**TestMethod.java C(
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*/ p!YK~cH
[  
package NetFox; zx}+Q B0  
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public class TestMethod { HD=F2p  
baII!ks  
hYkkr&  
public TestMethod() =
Z:]%  
{ ///xx/weblogic60b2_win.exe wg?}c ;  
try{ (46'#E z[F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $3HqVqF^R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,]2?S5R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =){G  
fileFetch.start(); uxU-N  
} cWkg.ri-x  
catch(Exception e){e.printStackTrace ();} 1WMZ$vsQUb  
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fAULuF  
} -`k>(\Q<d  
 9BtGzI\  
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public static void main(String[] args) 8{G!OBxc\.  
{ X#&5?oq`  
new TestMethod(); 5eori8gr7  
} rV%68x9  
} Vpnk>GWD  
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