http断点续传简单实现（java)

/* S8S<>W  
**SiteFileFetch.java jO5R0^w  
*/ a,EApUWw  
package NetFox; L2NO_N  
import java.io.*; +^@;J?O  
import java.net.*; ){_D  
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public class SiteFileFetch extends Thread { 8`$lsD  
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SiteInfoBean siteInfoBean = null; //文件信息Bean r/G6O  
long[] nStartPos; //开始位置 qRX:eo  
long[] nEndPos; //结束位置 GELxS!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F:vHbs `y  
long nFileLength; //文件长度 {&qB!axj  
boolean bFirst = true; //是否第一次取文件 l7p*::(9  
boolean bStop = false; //停止标志 !(&N
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File tmpFile; //文件下载的临时信息 v[}g+3a  
DataOutputStream output; //输出到文件的输出流 \/ 9s<  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） sz?/4tY
 
public SiteFileFetch(SiteInfoBean bean) throws IOException l+V#`S*q  
{ h^`!kp  
siteInfoBean = bean; R, J(]ew  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); doj$chy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >axf_k  
if(tmpFile.exists ()) Qgel^"t]i  
{ kZfUwF:yN  
bFirst = false; bVbh| AA  
read_nPos(); hj<h]dhp  
} 0>aAI3E  
else d9E'4Zm  
{ "=/YPw^0  
nStartPos = new long[bean.getNSplitter()]; x9lG$0k:V  
nEndPos = new long[bean.getNSplitter()]; n}T;q1  
} o`EL)K{  
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} U>@st="  
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public void run() u\uYq  
{ >bo_  
//获得文件长度 55<f  
//分割文件 Px$4.b[{_Y  
//实例FileSplitterFetch fzhCV  
//启动FileSplitterFetch线程 ZB|y  
//等待子线程返回 F(5(cr 7K  
try{ TSPFi0PP  
if(bFirst) lZI?k=rWv  
{ m%[U
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nFileLength = getFileSize(); MD62ObK!  
if(nFileLength == -1) =;!$Qw4  
{ jJB+UF=  
System.err.println("File Length is not known!"); =MP?aH [  
} ;%/Kh :Vg  
else if(nFileLength == -2) b;AGw3SF  
{ e2@{Ab  
System.err.println("File is not access!"); jI
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} x U1](O  
else ux 7^PTgcO  
{ Te:
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for(int i=0;i<nStartPos.length;i++) L]_1z  
{ uv}?8$<\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 10C,\  
} vp#AD9h1  
for(int i=0;i<nEndPos.length-1;i++) Fhr5)Z  
{ G5
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nEndPos = nStartPos[i+1]; :hA=(iz  
} |hlc#t?  
nEndPos[nEndPos.length-1] = nFileLength; ];n3H~2  
} 7[)IP:I>  
} R54wNm@  
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//启动子线程 c-dOb.v0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; i- v PJg1  
for(int i=0;i<nStartPos.length;i++) |d@%Vb
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{  #"6O3.P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c[h{C!d1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ns*&;x9  
nStartPos,nEndPos,i); 2yt)"DnFk  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Vp5i i]B4  
fileSplitterFetch.start(); tt=JvI9>  
} j-% vLL/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n&j@7R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); O8\dMb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &YU; K&  
nEndPos = " + nFileLength); u3Qm"?$`  
// fileSplitterFetch[nPos.length-1].start(); 5,;>b^gXY`  
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//等待子线程结束 C(Bh<
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//int count = 0;
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//是否结束while循环 >*v P*H:P  
boolean breakWhile = false; 7tEkQZMDI  
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while(!bStop) _3_kvs  
{ L T.u<ThR}  
write_nPos(); LrL ZlJf  
Utility.sleep(500); KO~_  
breakWhile = true; ,'KS:`m!  
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for(int i=0;i<nStartPos.length;i++) de&*#O5  
{ zOEdFU{x  
if(!fileSplitterFetch.bDownOver) f <,E  
{ 'DDlX3W-  
breakWhile = false; sX :)g>b   
break; ?hXeZB+b4  
} 8H%-/2NW  
} WFYbmfmV  
if(breakWhile) AxsTB9/  
break; ,?OWwm&J  
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//count++; pr;z>|FgA>  
//if(count>4) &N`s@K
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// siteStop(); a___SYl 'K  
} \fk%^1XY  
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System.err.println("文件下载结束！"); Rfk8trD B  
} O/|,rAE  
catch(Exception e){e.printStackTrace ();} (pU@$H  
} 3 W%Bsqn  
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//获得文件长度 `[&) X  
public long getFileSize() 5f` a7R  
{ hI^Hqv  
int nFileLength = -1; y,.X5#rnX*  
try{ >Z\{P8@k
0  
URL url = new URL(siteInfoBean.getSSiteURL()); doERBg`Jh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '1jG?D  
httpConnection.setRequestProperty("User-Agent","NetFox"); -F-RWs{yS  
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int responseCode=httpConnection.getResponseCode(); r
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if(responseCode>=400) /CE]7m,7~K  
{ vq.~8c1  
processErrorCode(responseCode); ;?*`WB  
return -2; //-2 represent access is error =Fd!wkB'{  
} GW29Rj1  
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String sHeader; j.b7<Vr4;  
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for(int i=1;;i++) BkH- d z  
{ J#```c
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5)T=^"IHXi  
//Utility.log(in.readLine()); \L-K}U>
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sHeader=httpConnection.getHeaderFieldKey(i); ^hc&rD)_  
if(sHeader!=null) o/;kzi  
{ w`N|e0G@  
if(sHeader.equals("Content-Length")) BotGPk><c  
{ ~
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "M GX(SQ  
break; 1feZ`P;  
} o:p6[SGd  
} NB["U"1[^E  
else "<#-#j  
break; [32]wgw+{1  
} |<Cz#| ,q  
} }k`-n32)|  
catch(IOException e){e.printStackTrace ();} TIs~?wb$  
catch(Exception e){e.printStackTrace ();} o|tq&&! <  
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Utility.log(nFileLength); 'V*ixK8R0  
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return nFileLength; O!,WH?
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} M_:_(y>l  
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x344}\  
//保存下载信息（文件指针位置） zKY 9'y  
private void write_nPos() f>*D@TrU  
{ 3N5un`K7  
try{ y4V~fg;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ke+3J\;>  
output.writeInt(nStartPos.length); (9"w{pnlLc  
for(int i=0;i<nStartPos.length;i++) J'Z!`R|  
{ MHuQGc"e+4  
// output.writeLong(nPos); 'aWrjfD
y:  
output.writeLong(fileSplitterFetch.nStartPos); 9*thqs3J#d  
output.writeLong(fileSplitterFetch.nEndPos); g
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} 4*)a3jI?  
output.close(); ^B>
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} 4TPAD)C  
catch(IOException e){e.printStackTrace ();} e[Tu.$f-  
catch(Exception e){e.printStackTrace ();} lj U|9|v  
} w,6zbI/  
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//读取保存的下载信息（文件指针位置） p4Wy2.&Q  
private void read_nPos() c}QWa"\2n  
{ lBYc(cr  
try{ feSj3,<!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \V1geSoE  
int nCount = input.readInt(); 4 8}\  
nStartPos = new long[nCount]; H*gX90{!2  
nEndPos = new long[nCount]; Z4"SKsJT/>  
for(int i=0;i<nStartPos.length;i++) 65P*Gu?  
{ Ib~n}SA  
nStartPos = input.readLong(); *VbB'u:  
nEndPos = input.readLong(); <hJ%]]  
} aX)k(*|  
input.close(); aJ4y%Gy?  
} SY[7<BUZ  
catch(IOException e){e.printStackTrace ();} ;$VQRXq  
catch(Exception e){e.printStackTrace ();} r Ljb'\<*  
} 0LjF$3GpZ  
g }%$VUSA  
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private void processErrorCode(int nErrorCode) C:?mOM#_  
{ #835$vOe  
System.err.println("Error Code : " + nErrorCode); 37F&s  
} %u)niY-g
 
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//停止文件下载 4@Q`8N.  
public void siteStop() !U6 x_  
{ Xcy Xju#"p  
bStop = true; d'x'hp
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for(int i=0;i<nStartPos.length;i++) wa)E.(x  
fileSplitterFetch.splitterStop(); [!<W{ ($5  
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} +(pFU\&U3H  
} LE'8R~4.<  
//负责部分文件的抓取 gf&\)"  
**FileSplitterFetch.java IwTAM9n  
*/ " iz'x-wy  
package NetFox; k)a3j{{  
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import java.io.*; #77p>zhY  
import java.net.*; y|+n77[Gv  
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public class FileSplitterFetch extends Thread { KeGGF]=>  
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String sURL; //File URL
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long nStartPos; //File Snippet Start Position 
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long nEndPos; //File Snippet End Position S,*  
int nThreadID; //Thread's ID <Rno;  
boolean bDownOver = false; //Downing is over GY~Q) Z  
boolean bStop = false; //Stop identical Hy*_4r  
FileAccessI fileAccessI = null; //File Access interface W`d\A3v  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pO10L`|  
{ d~>d\K%v  
this.sURL = sURL; ^@4$O|3Wh'  
this.nStartPos = nStart; H[u
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this.nEndPos = nEnd; WlF}R\N!  
nThreadID = id; T\ cJn>kCn  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -!ARVf *  
} v)!C Dpw  
^&Re-{ES]  
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public void run()  g%.;ZlK  
{ egd%,`  
while(nStartPos < nEndPos && !bStop) hE9UWa.Q>  
{ QrX 5Kwq  
*=KX0%3  
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try{ hk7kg/"  
URL url = new URL(sURL); pAm L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E[nJ'h<h  
httpConnection.setRequestProperty("User-Agent","NetFox"); Tp.t.Qic  
String sProperty = "bytes="+nStartPos+"-"; 5?yc*mOZ  
httpConnection.setRequestProperty("RANGE",sProperty); Xh[02iL-  
Utility.log(sProperty); 7R{(\s\9:  
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InputStream input = httpConnection.getInputStream(); >X$I:M<L  
//logResponseHead(httpConnection); xV}ybRKV  
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byte[] b = new byte[1024]; B S^P&TR!  
int nRead; WS7a]~3'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4b}94e@(N  
{ S*D Bzl  
nStartPos += fileAccessI.write(b,0,nRead); $.g)%#h:  
//if(nThreadID == 1) +
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #6'+e35^8  
} iDdmr32E  
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Utility.log("Thread " + nThreadID + " is over!"); Z4ZR]eD  
bDownOver = true; _l$1@  
//nPos = fileAccessI.write (b,0,nRead); WNa#X]*E)  
} /DC\F5 G  
catch(Exception e){e.printStackTrace ();} 4Up3x+bg  
} Aq5@k\[  
} %ylpn7I\6  
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//打印回应的头信息 yJMHm8OB7  
public void logResponseHead(HttpURLConnection con) q]}1/JZS  
{ ;V:Cf/@@R  
for(int i=1;;i++) W4ygJL7 6  
{ UomO^P  
String header=con.getHeaderFieldKey(i); #R#o/@|  
if(header!=null) c9<&+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d=$1Z.]  
Utility.log(header+" : "+con.getHeaderField(header)); 'y<<ce*  
else B+pJWl8u  
break; Kd%>:E*  
} D,<#pNO_  
} `(dRb  
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public void splitterStop() !J%m7A  
{ )tB1jcI;  
bStop = true; f|cF
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} #ozQF~
 
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} L[LgQ7esQ  
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/* f[;l7  
**FileAccess.java M)T
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*//文件访问(定位，写) +'{@Xe}  
package NetFox; Z7@~#)3  
import java.io.*; 45DR%cz  
w*-1*XNA  
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public class FileAccessI implements Serializable{ .:(N1n'>1  
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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 NW=tZVQ<X  
RandomAccessFile oSavedFile; uJX(s6["=  
long nPos; H{4/~Z  
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public FileAccessI() throws IOException F,l%SQCyj  
{ ZR|cZH1}C  
this("",0); (qQ|s@O  
} |vLlEN/S  
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public FileAccessI(String sName,long nPos) throws IOException SyWLPh  
{ g0n 5&X  
oSavedFile = new RandomAccessFile(sName,"rw"); {k#RWDespy  
this.nPos = nPos; 4\?GA`@  
oSavedFile.seek(nPos); C $r]]MSj  
} G'\x9%  
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public synchronized int write(byte[] b,int nStart,int nLen) kpU-//lk+  
{ ti}g?\V
T  
int n = -1; }K%y'D  
try{ Ksu_4dE  
oSavedFile.write(b,nStart,nLen); /t<C_lLM  
n = nLen; /cN. -lEo%  
} k.dQ;v}  
catch(IOException e) Ue8k9%qV  
{ A` iZ"?  
e.printStackTrace (); Ub%sw&QG(9  
} KW[Jft  
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return n; wV,l }Xb-  
} a!!>}e>Cj*  
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} |k-IY]6  
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/* D]h~\  
**SiteInfoBean.java = Nd&My  
*/ fjh0Z i45  
package NetFox; 1 iWe&I:  
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public class SiteInfoBean { *k7vm%#ns  
^:yg,cS|Be  
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private String sSiteURL; //Site's URL *YI>Q@F9  
private String sFilePath; //Saved File's Path 9u->.O: p  
private String sFileName; //Saved File's Name ;Npv 2yAab  
private int nSplitter; //Count of Splited Downloading File b3,&R
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public SiteInfoBean() \~Yy
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{//nSplitter的缺省值为5  xlH?J;$  
//default value of nSplitter is 5 xzRs;AXOp  
this("","","",5); w?+v+k\  
} %j[DG_  
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)/:&i<Q:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) oiS>:de%tc  
{ H3?HQ>&O7  
sSiteURL= sURL; u7Xr!d+wR  
sFilePath = sPath; #78P_{#!  
sFileName = sName; s|1BqoE  
this.nSplitter = nSpiltter; k$hNibpkt  
;{Sgv^A  
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} 2[*r9%W  
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public String getSSiteURL() 9_6.%qj&  
{ ~<%/)d0  
return sSiteURL; -C7IUat<  
} t!g9,xG<X  
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public void setSSiteURL(String value) ^rKA=siz  
{ Y\qiYra  
sSiteURL = value; *$KUnd
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} YJ&K0%R  
bYKyR}e  
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public String getSFilePath() u I \zDR  
{ #()u=)
 
return sFilePath; .o2]ndT/J  
} [;Q8xvVZ'  
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public void setSFilePath(String value) KXg
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{ &tULSp@J  
sFilePath = value; }Ot I8;>  
} G$5N8k[2  
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public String getSFileName() ~)zoIM\  
{ A-GRuC  
return sFileName; b,
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} M=n_;3,o  
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public void setSFileName(String value) Q/%(&4>'y  
{ EzDj,!!<w  
sFileName = value; `J>76WN  
} ;?y*@*2u  
_d
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public int getNSplitter() o|s JTY  
{ #L{+
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return nSplitter; .
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} RsYn6ozb  
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public void setNSplitter(int nCount) 0`KB|=>  
{ M1MpR+7S  
nSplitter = nCount; 5pBQ~m3  
} <(]e/}  
} w>IYrSaa>  
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/* iI[Z|"a21  
**Utility.java >@yHa'*9S  
*/ 3&D;V;ON}_  
package NetFox; &=sVq^d@qe  
s<I[)FQVr  
<"uT=]wZ=  
public class Utility { o@`& h} $  
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public Utility() i>9/vwe  
{ CjzfU*G  
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} 7L[HtwI  
|S5N$[  
//线程睡眠 9})!~r;|  
public static void sleep(int nSecond) 41<.e`{  
{ zfE;)K^"  
try{ aW8Bx\q  
Thread.sleep(nSecond); ?-g=Rfpag  
} K_iy^|0)5]  
catch(Exception e) !af35WF  
{ @15%fX`*o  
e.printStackTrace (); kU8V,5  
} 4]N`pD5  
} 2kTLj2@o,  
AW8"@  
//日志 P!C!E/Jf5  
public static void log(String sMsg) rsP3?.E  
{ u
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System.err.println(sMsg);  0gBD  
} _Cv({m&N  
%C= {\]-2~  
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public static void log(int sMsg) "`DCXn#mB  
{ krTH<- P  
System.err.println(sMsg); bA-=au?o5  
} '#SacJ\L7  
} Q{Gi**<  
#,O<E@E  
;T}#-`O_Im  
/* }Po&6^  
**TestMethod.java Yn,dM~|Cc
 
*/ R/ 7G  
package NetFox; "t+VF4r  
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public class TestMethod { cLH|;  
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public TestMethod() m :ROq  
{ ///xx/weblogic60b2_win.exe br"p D-}  
try{ fbSl$jn.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }-m/ 'Q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &oevgG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8jxgSB",  
fileFetch.start(); n 5NkjhP~Z  
} )< ~1AL  
catch(Exception e){e.printStackTrace ();} OGNjn9av  
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" *xQN "F  
} /sENoQR  
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public static void main(String[] args) c"%XE#D  
{ :8U=L'4  
new TestMethod(); 0-EhDGa]r  
} |b'fp1</  
} + )?1F  
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