http断点续传简单实现（java)

/* E:N~c
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**SiteFileFetch.java J['paHSF  
*/ + (cTzY  
package NetFox; -VESe}c:nQ  
import java.io.*; ~(xIG
 
import java.net.*; s|U?{Byb!  
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public class SiteFileFetch extends Thread { VR>;{>~  
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SiteInfoBean siteInfoBean = null; //文件信息Bean uhFj|r$$  
long[] nStartPos; //开始位置 AWP CJmr  
long[] nEndPos; //结束位置 vmW4 3K;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h,q%MZ==^s  
long nFileLength; //文件长度 <aR8fU  
boolean bFirst = true; //是否第一次取文件 ;K:)R_H  
boolean bStop = false; //停止标志 aZYa<28?L%  
File tmpFile; //文件下载的临时信息 dE*n
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DataOutputStream output; //输出到文件的输出流 =>Vo|LBoe  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） r[zxb0YA  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1FS Jqa
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{ \k1psqw^O  
siteInfoBean = bean; J(0.eD91v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D5]sf>~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Nw}y_Qf{  
if(tmpFile.exists ()) !aD/I%X  
{ Zi=Nr3b  
bFirst = false; TE4{W4I  
read_nPos(); <a|$Bl  
} Ctxs]S tU%  
else Yw=Ve 0  
{ #5kQn>R  
nStartPos = new long[bean.getNSplitter()]; xn&G`  
nEndPos = new long[bean.getNSplitter()]; <@}~
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} *]fBd<(8  
d*=P8QwL|  
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} \FSkI0  
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public void run() 0(;d<u)fS  
{ Efb>ZQ  
//获得文件长度 &inu mc  
//分割文件 8H3|i7.1h  
//实例FileSplitterFetch @eN x:}  
//启动FileSplitterFetch线程 
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//等待子线程返回 ?5nF` [rx  
try{ e%&2tf4  
if(bFirst) SUXRWFl  
{ T^8t<S@`  
nFileLength = getFileSize(); iK6L\'k  
if(nFileLength == -1) nsqs*$  
{ N.C<Mo  
System.err.println("File Length is not known!"); zR/d:P
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} 'H2TwSbIXI  
else if(nFileLength == -2) iIq='xwa9  
{ mHo}, |  
System.err.println("File is not access!"); .Y!*6I  
} +$_W4lf|E2  
else FFl[[(`%D  
{ <J@Y=#G$2  
for(int i=0;i<nStartPos.length;i++) "P=OpFV  
{ +?n81|7`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1vBR\!d?7  
} l;: L0(('  
for(int i=0;i<nEndPos.length-1;i++) 'D8WNZ8Q  
{ w1/pwzn  
nEndPos = nStartPos[i+1]; QF(.fq8, U  
} |k:MXI  
nEndPos[nEndPos.length-1] = nFileLength; gk\IivPb  
} 3hr&p{/  
} ]:JoGGE a0  
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//启动子线程 9@ 6y(#s
 
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nnX,_5s  
for(int i=0;i<nStartPos.length;i++) Jz s.)  
{  Q0'xn  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Mxn>WCPo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @.T '>;izr  
nStartPos,nEndPos,i); "o/:LCE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Zf |%t  
fileSplitterFetch.start(); kt.z,<w5O  
} 1HG~}E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m5SJB]a/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7.$0LN/a!Z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", pw*<tXH!  
nEndPos = " + nFileLength); {,tEe'H7  
// fileSplitterFetch[nPos.length-1].start(); nVV>;e[  
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//等待子线程结束 X>j% y7v  
//int count = 0; Oemi}  
//是否结束while循环 `uy)][j-  
boolean breakWhile = false; ulV)X/]1  
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while(!bStop) 9l9n
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{ Ub*Gv(Pg  
write_nPos(); zE5%l`@|o  
Utility.sleep(500);  XeDiiI
 
breakWhile = true; Vu0jNKUV  
Ro$'|}(+A  
4G0Er?D   
for(int i=0;i<nStartPos.length;i++) =4uL1[0'  
{ *Hy-D</w%  
if(!fileSplitterFetch.bDownOver) tM]~^U  
{ '9%72yG  
breakWhile = false; R)d1]k8  
break; ,j^ /~  
} m!5P5U x  
} 5v"QKI  
if(breakWhile) YU.aZdA&V3  
break; s~$ZTzV  
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^%V'l-}/  
//count++; lN
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//if(count>4) \ni?_F(Y  
// siteStop(); A;n3""  
} PjNOeI@G  
wgxr8;8`q  
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System.err.println("文件下载结束！"); 
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} *ndXZ64  
catch(Exception e){e.printStackTrace ();} TJ8IYo| D  
} 6gV-u~j[#  
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p9Zi}!  
//获得文件长度 C-lv=FJEk/  
public long getFileSize() ;75K:_  
{ QNn\wz_)  
int nFileLength = -1; /"?yB$s  
try{ _0ki19rs  
URL url = new URL(siteInfoBean.getSSiteURL()); Z .VIb|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p/L|;c  
httpConnection.setRequestProperty("User-Agent","NetFox"); UXwnE@`F  
mH2XwA|  
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int responseCode=httpConnection.getResponseCode(); OAO|HH  
if(responseCode>=400) FIhq>L.q4  
{ .Nz2K[  
processErrorCode(responseCode); fVx<f.xuW  
return -2; //-2 represent access is error o^FlQy\  
} U;u
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String sHeader; :,%~R2  
$(B|$e^:(  
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for(int i=1;;i++) >Q#h,x~vu  
{ T#kPn#|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0w9)#e+JS  
//Utility.log(in.readLine()); TELN4*  
sHeader=httpConnection.getHeaderFieldKey(i); 3*x_S"h  
if(sHeader!=null) ")m0{  
{ QG {KEj2V  
if(sHeader.equals("Content-Length")) \Fg%V>  
{ 69ZGdN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); qww*  
break; %0l'Nuz  
} UngDXD )  
} a)w *  
else  @v&hr  
break; )(yD"]co  
} "
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} ;:2]++G  
catch(IOException e){e.printStackTrace ();} F!.Z@y P  
catch(Exception e){e.printStackTrace ();} +.^BM/z^O  

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Utility.log(nFileLength); a!rU+hiC  

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return nFileLength; 6HocF/Ye  
} Gy 0 m  
:}(Aq;}X  
:_9MS0  
//保存下载信息（文件指针位置） B!{vSBq  
private void write_nPos() ,9;RP/"7  
{ Kv(2x3("  
try{ E;m]RtvH  
output = new DataOutputStream(new FileOutputStream(tmpFile)); VRden>vKN  
output.writeInt(nStartPos.length); CqK&J /8  
for(int i=0;i<nStartPos.length;i++) mY6d+  
{ 0?c2=Y  
// output.writeLong(nPos); WOBLgM,|  
output.writeLong(fileSplitterFetch.nStartPos); ! Rrk
 
output.writeLong(fileSplitterFetch.nEndPos); j#4 Iu&YJ  
} 5B6twn~[  
output.close(); [ye!3h&]  
} pY@$N&+W  
catch(IOException e){e.printStackTrace ();} -u+@5K;^Y  
catch(Exception e){e.printStackTrace ();} %-9?rOr  
} *iLlBE  
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//读取保存的下载信息（文件指针位置） K9-;-{qb  
private void read_nPos() AzFd#P  
{ u NmbR8Mx  
try{ Ub[SUeBGH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !@>_5p>q*  
int nCount = input.readInt(); Vx'82CIC  
nStartPos = new long[nCount]; b;Nm$`2  
nEndPos = new long[nCount]; U-^qVlw  
for(int i=0;i<nStartPos.length;i++) M9[52D!{  
{ P;~`%,+S  
nStartPos = input.readLong(); ?X $#J'U;  
nEndPos = input.readLong(); Qc4r?7S<  
} @QOlo-u  
input.close(); Oly"ll*K  
}  Y7*8A,  
catch(IOException e){e.printStackTrace ();} 6gfn5G  
catch(Exception e){e.printStackTrace ();} A]<+Aq@{  
} )ZZjuFQJ)  
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Q]h.{nN#PK  
private void processErrorCode(int nErrorCode) Q)]C~Q  
{ Q[PVkZ  
System.err.println("Error Code : " + nErrorCode); 8Dy5g  
} 0FN;^hP5|  
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{"v~1W)  
//停止文件下载 FZFYwU\~.L  
public void siteStop() QK~44;LVIJ  
{ l<3X:)  
bStop = true; )NF5,eD  
for(int i=0;i<nStartPos.length;i++) %_P[ C}4  
fileSplitterFetch.splitterStop(); 8U8%XIEJ  
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} 1s-dqHz"s  
} D;1?IeS  
//负责部分文件的抓取 @n|Mr/PAj  
**FileSplitterFetch.java *r)/Vx`S  
*/ d9=i{i3  
package NetFox; 8'sT zB]  
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7!qO*r  
import java.io.*; xdLMy#U2  
import java.net.*; ()}(3>O-  
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public class FileSplitterFetch extends Thread { s78MXS?py  
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String sURL; //File URL iY,FfuE  
long nStartPos; //File Snippet Start Position APgjT';P^  
long nEndPos; //File Snippet End Position NZb}n`:  
int nThreadID; //Thread's ID "1P[D'HV4|  
boolean bDownOver = false; //Downing is over %~e+H|  
boolean bStop = false; //Stop identical )k^y<lC2a  
FileAccessI fileAccessI = null; //File Access interface '^|u\$&U  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :~^_*:  
{ bmzY^ %a  
this.sURL = sURL; | V:9 ][\  
this.nStartPos = nStart; :kMF.9U:  
this.nEndPos = nEnd; PtTL tiE~  
nThreadID = id; }/bxe0px  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1agNwFd~  
} FG:t2ea  
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public void run() oBS m>V
 
{ p3,m),  
while(nStartPos < nEndPos && !bStop) )Fsc0_  
{ Te6cw+6  
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try{ ^?V9  
URL url = new URL(sURL); ;x|7"lE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h`n) b  
httpConnection.setRequestProperty("User-Agent","NetFox"); JT p+&NS  
String sProperty = "bytes="+nStartPos+"-"; 0f5c#/7C9  
httpConnection.setRequestProperty("RANGE",sProperty); %y
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Utility.log(sProperty); Q2>o+G  
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InputStream input = httpConnection.getInputStream(); ^`S.Mw.  
//logResponseHead(httpConnection); f6,?Yex8B  
}`pxs  
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byte[] b = new byte[1024]; -Hh.8(!XoO  
int nRead; p:NIRs  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) GYt|[GC  
{ )61X,z  
nStartPos += fileAccessI.write(b,0,nRead); ],~H3u=s3  
//if(nThreadID == 1) h'nXV{N0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cC*H.N  
} <y=+Gh  
,p>@:C/M  
%a:>3! +  
Utility.log("Thread " + nThreadID + " is over!"); hHk9O?  
bDownOver = true; $KVCEe!X  
//nPos = fileAccessI.write (b,0,nRead); i7b^b>B|e  
} :w<Ga8\tZ  
catch(Exception e){e.printStackTrace ();} ri/CLq^D  
} dw>1Ut{"3  
} P:>]a$Is  
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//打印回应的头信息 Q_)$Ha{>H,  
public void logResponseHead(HttpURLConnection con) r>ag(^J\  
{ D0}r4eA  
for(int i=1;;i++) kQ`p\}7_  
{ :Vy*MPS5  
String header=con.getHeaderFieldKey(i); m%cwhH_B  
if(header!=null) FL{$9o\@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?J@P0(M#  
Utility.log(header+" : "+con.getHeaderField(header)); 3UX6Y]E3  
else FN/siw(?3  
break; CjGQ  
} u[HamGxx$u  
} .*X=JFxl  
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public void splitterStop() ] T<#bNK\1  
{ 
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bStop = true; 7Bym?  
} 6~-,.
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} f28bBuv1?  
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/* >QdT7gB  
**FileAccess.java !;UoZ~  
*//文件访问(定位，写) nT%ko7~-  
package NetFox; >qVSepK3  
import java.io.*; (
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public class FileAccessI implements Serializable{ ^ib =fLu  
mqtYny'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 iS< ^MD  
RandomAccessFile oSavedFile; R;zf x/  
long nPos; uO)vGzt3^x  
#||D,[ _=+  
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public FileAccessI() throws IOException &x\cEI)!  
{ 4t-l@zFWb  
this("",0); [V_+/[AA)  
} Q-7L,2TL  
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public FileAccessI(String sName,long nPos) throws IOException c#f@v45  
{ x!6<7s  
oSavedFile = new RandomAccessFile(sName,"rw"); vY7@1_"  
this.nPos = nPos; X}wo$
t  
oSavedFile.seek(nPos); 4y.qtiIP>$  
} &smZ;yb|'h  
!4T!@"#  
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public synchronized int write(byte[] b,int nStart,int nLen) Q_Wg4n5  
{ s!S_Bt):3  
int n = -1; I_
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try{ IL1iTRH  
oSavedFile.write(b,nStart,nLen); 4hxa|f  
n = nLen; v o4U%  
} K $WMrp  
catch(IOException e) +4Fw13ADE  
{ 1Ko4O)L]&  
e.printStackTrace (); &WeN{  
} G+2 ,x0(  
)}P/xY0  
cwOa"]t}  
return n; kS?CKd9by  
} ^wD`sj<Qg  
~(#iGc]7  
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} *^w}SE(  
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8 C9ny}  
/* rHi4Pw{L  
**SiteInfoBean.java dtE"1nR  
*/ [$F*R@,&  
package NetFox; %WC^aKfY  
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public class SiteInfoBean { pSI8"GwQ  
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private String sSiteURL; //Site's URL -:kIIK   
private String sFilePath; //Saved File's Path J"F
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private String sFileName; //Saved File's Name 7<Qmpcp =  
private int nSplitter; //Count of Splited Downloading File wFMw&=j  
4*D"*kR;  
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public SiteInfoBean() V/:
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{//nSplitter的缺省值为5 9 r&JsCc  
//default value of nSplitter is 5 ~ivOSr7s}  
this("","","",5); a6Joa&`dv  
} )\j dF-s  
!!ma]pB,  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0m=57c$O  
{ n @,.  
sSiteURL= sURL; CxNxb)c &  
sFilePath = sPath; pp@B]We  
sFileName = sName; rLE+t(x(0  
this.nSplitter = nSpiltter; J .VZD  
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} }'faf{W  
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public String getSSiteURL() 74a@/'WbE  
{ oam;hmw  
return sSiteURL; o(H.1ESk  
} 9e c},~(  
=R~zD4{"  
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public void setSSiteURL(String value) Mi{ns $B%  
{ ?3 k_YN"  
sSiteURL = value; 5@-H8*  
} Yufjy=!  
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JT!9LNh;R`  
public String getSFilePath() h5pfmN\-5  
{ sei2\l8q  
return sFilePath; PEm2w#X%L  
} 5&h">_j  
N>,`TsUwW  
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public void setSFilePath(String value) _Gf-s51s  
{ kY!zBk  
sFilePath = value; W&:0J  
} F>3 o0ke}  
1_#;+S  
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public String getSFileName() dq`{fqGl  
{ 8e3eQ  
return sFileName; aidQ,(PDj  
} P tLWFO  
AFm9"mQrw  
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public void setSFileName(String value) )XGz#C_P  
{ L
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sFileName = value; \/?J)k3H.  
} =4co$oD}  
|/^S%t6*  
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public int getNSplitter() $+_1F`  
{ fK+ 5  
return nSplitter; S2;^  
} 80_w_i+  
*4Ldh}S!  
} `r.fD  
public void setNSplitter(int nCount) <n06(9BF  
{ N0-J=2  
nSplitter = nCount; N0Y4m_dm*  
} y.J>}[\&x  
} fn=A_ i  
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/* %),u0:go  
**Utility.java 5cinI^x)f  
*/ MTZCI}  
package NetFox; Z#-N$%^F  
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[M,4qe8,}  
public class Utility { `D |/g;  
77yYdil^W+  
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public Utility() bTm
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{ nEd "~  
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G^
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} ?z#*eoPr  
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//线程睡眠 ]6[+tpx  
public static void sleep(int nSecond) 3CjixXaA$  
{ mV`R'*1UC  
try{ H"8B4~*7H  
Thread.sleep(nSecond); tEvDAI} 5  
} 7~XA92  
catch(Exception e) vm_]X{80
;  
{ W/xPVmnV  
e.printStackTrace (); -43>?m/a  
} B I)@n:p  
} qvB{vU  
|cY,@X,X6  
//日志 ufIv
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public static void log(String sMsg) Cj-&L<  
{ 1:](=%oM&k  
System.err.println(sMsg); x@Z{5w_a  
} #f24a?n|  
4RB
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gM>?w{!LBx  
public static void log(int sMsg) '~K]=JP  
{ KFHZ3HZ:>  
System.err.println(sMsg); _7Y-gy#\a  
} =3QhGFd  
} (b//YyqN  
ub-e
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FEu"b@v  
/* SfC* ZM}
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**TestMethod.java ||QK)$"  
*/ %p )"_q!ge  
package NetFox; cMZy~>  
2SC-c `9)  
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public class TestMethod { U|tacO5w`  
UHvA43  
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public TestMethod() 03v+eT  
{ ///xx/weblogic60b2_win.exe j;@a~bks6z  
try{ heou\;GI"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +5*bU
1}O  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \{:A&X~\!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jDb\4QyC  
fileFetch.start(); LxhS 9  
} (KyOo,a  
catch(Exception e){e.printStackTrace ();} re[5lFQ~Z  
wrgB =o  
2}pZy
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} BYEZ[cM  
1bQO:n):~  
c.Sd~k:3  
public static void main(String[] args) |YROxY"ML  
{ >P~*@>e  
new TestMethod(); j AOy3c  
} zu{K"7Bx  
} 1gkpK`u(B  
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