http断点续传简单实现（java)

/* b`18y cVME  
**SiteFileFetch.java UAUo)VVi"  
*/ )v0m7Lv#/  
package NetFox; A%%WPBk{O  
import java.io.*; rw8db'  
import java.net.*; zF\k*B  
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public class SiteFileFetch extends Thread { &d9";V"E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean gd/W8*NFR  
long[] nStartPos; //开始位置 l,,5OZw  
long[] nEndPos; //结束位置 9K FWa0G  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L!-T`R8'c  
long nFileLength; //文件长度 \CU.'|X  
boolean bFirst = true; //是否第一次取文件 >E[cl\5$E  
boolean bStop = false; //停止标志 6M259*ME  
File tmpFile; //文件下载的临时信息 %hcY [F<  
DataOutputStream output; //输出到文件的输出流 6 )xm?RK  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Y~fds#y0  
public SiteFileFetch(SiteInfoBean bean) throws IOException S(9fGh  
{ =;^2#UxXA&  
siteInfoBean = bean; ]7c715@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e@=Bl-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); } Tp!Ub\Cc  
if(tmpFile.exists ()) q$>At}4  
{ )6IO)P/Q~  
bFirst = false; }$81FSKh  
read_nPos(); mA3C)V  
} S%g`X  
else '0/t|V<  
{ 8[2^`g  
nStartPos = new long[bean.getNSplitter()]; DkQy.  
nEndPos = new long[bean.getNSplitter()]; :|N5fkhN  
} A4 o'EQ?~  
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} ?w /tq!  
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public void run() u@[D*c1!H  
{ vKol@7%N  
//获得文件长度 PL%_V ?z  
//分割文件 nuhKM.a{  
//实例FileSplitterFetch dhsQfWg#}  
//启动FileSplitterFetch线程 }3=]1jH6  
//等待子线程返回 NC@OmSR\0  
try{ z.P) :Er  
if(bFirst) u= !?<Q  
{ &*[T
 
nFileLength = getFileSize(); V.\do"m  
if(nFileLength == -1) iHWl%]7sN  
{ OpUC98p?@  
System.err.println("File Length is not known!"); trtI^^/%  
} ` *h-j/M  
else if(nFileLength == -2) w*\)]bTs  
{ ?IGT!'  
System.err.println("File is not access!"); y`7BR?l  
} 4~DFtWbf  
else h
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{ JEs?Rm1^.  
for(int i=0;i<nStartPos.length;i++) ON] z-
 
{ #R'm|En'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N1+%[Uh9)  
} Th'6z#h:U  
for(int i=0;i<nEndPos.length-1;i++) :hCp@{  
{ OAR#* ~q  
nEndPos = nStartPos[i+1]; 7p@qzE  
} /wH]OD{  
nEndPos[nEndPos.length-1] = nFileLength; iK= {pd  
} 3dQV5E.  
} s?7g3H5#0k  
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/ ~w\Npf0  
//启动子线程 5e6]v2 k  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; IF$f^$  
for(int i=0;i<nStartPos.length;i++) $IUT5Gia`  
{ yzgDdAM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O-}{%)[ F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3-Xum*)Y  
nStartPos,nEndPos,i); bjZcWYT  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G>d@lt  
fileSplitterFetch.start(); [#M^:Q  
} bAGQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7M=`Z{=9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2u/~#Rt&*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", uiPfAPZ  
nEndPos = " + nFileLength); .@gv}`>  
// fileSplitterFetch[nPos.length-1].start(); Y u8a8p|  
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//等待子线程结束 'k{pWfn=<  
//int count = 0; 8{(;s$H~  
//是否结束while循环 59FAhEg  
boolean breakWhile = false; {ajaM'x  
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while(!bStop) vp{jh-&  
{ jDqe)uVvtV  
write_nPos(); Vf`1'GY  
Utility.sleep(500); "U4Sn'&h@  
breakWhile = true; 4b,N"w{v  
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for(int i=0;i<nStartPos.length;i++) aP>%iRk'J!  
{ )lTkqz8v  
if(!fileSplitterFetch.bDownOver) Z455g/=ye  
{ $NWXn,Y'  
breakWhile = false; N3!x7J7A  
break; 7D@O:yO  
} >Ke4lO"  
} F)z]QJOw  
if(breakWhile) ?MHVkGD  
break; `p|{(g'  
-WWa`,:  
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//count++; T&H[JQ/h  
//if(count>4) WSz#g2a  
// siteStop(); xrFFmQ<_W  
} )}0(7z Yu  
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System.err.println("文件下载结束！"); GKTrf\"c  
} t,gKN^P_  
catch(Exception e){e.printStackTrace ();} rn"'tvhm  
} A36dj  
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//获得文件长度 3P2H!r  
public long getFileSize() $Y5R^Y  
{ Fo|6 PoSo  
int nFileLength = -1; jeFX?]Q  
try{ 6}qp;mR E]  
URL url = new URL(siteInfoBean.getSSiteURL()); a^hDxeG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xX.fN7[  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y6~/H  
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int responseCode=httpConnection.getResponseCode(); $,ZBK6CT  
if(responseCode>=400) j7IX"O%f\  
{ (C dx7v2Nh  
processErrorCode(responseCode); {*RyT.J  
return -2; //-2 represent access is error .]SE>3  
} l}:&}  
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String sHeader; }1=V`N(  
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for(int i=1;;i++) _WO*N9Iz  
{ F'^6ra9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;7Cb!v1
 
//Utility.log(in.readLine()); [xe(FFl+  
sHeader=httpConnection.getHeaderFieldKey(i); se(ZiyHp  
if(sHeader!=null) P~HzNC  
{ Q(=}
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if(sHeader.equals("Content-Length")) h;?=:(  
{ rtd&WkU rD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d:cs8f4>  
break; 2+y<&[A8U  
} ];P$w.0  
} 1$2'N~`#U  
else 9#Gz2u$  
break; mxt fKPb  
} Y3KKskhLx  
} .
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catch(IOException e){e.printStackTrace ();} E&ou(Q={  
catch(Exception e){e.printStackTrace ();} @0H}U$l  
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Utility.log(nFileLength); 3 (Bd`=9  
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return nFileLength; E_ #MQ;n  
} yE1M+x./  
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//保存下载信息（文件指针位置） d~n|F|`:  
private void write_nPos() ZZ|a`U  
{ 53=5xE= `D  
try{ nQm7At  
output = new DataOutputStream(new FileOutputStream(tmpFile)); KKB&)R  
output.writeInt(nStartPos.length); *S,5  
for(int i=0;i<nStartPos.length;i++) mux_S2x9m\  
{ nW#UBtZ  
// output.writeLong(nPos); *-0tj~)>  
output.writeLong(fileSplitterFetch.nStartPos); H <7r  
output.writeLong(fileSplitterFetch.nEndPos);  ntK#7(U'  
} 0wL-Ak#v  
output.close(); 6^_:N1@  
} T:k-`t0":N  
catch(IOException e){e.printStackTrace ();} /<ODP6Yy;  
catch(Exception e){e.printStackTrace ();} GxjmHo  
} V/xGk9L~  
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)%H@.;cD_r  
//读取保存的下载信息（文件指针位置） k<xPg5  
private void read_nPos() [HNWM/ff7+  
{ =qG%h5]n  
try{ cXP*?N4Cf  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t6m&+N  
int nCount = input.readInt(); {6}H}_(]  
nStartPos = new long[nCount]; EMK>7 aks  
nEndPos = new long[nCount]; B. '&[A  
for(int i=0;i<nStartPos.length;i++) "*E06=fiG  
{ YhQ;>Ko  
nStartPos = input.readLong(); {-?^j{O0.  
nEndPos = input.readLong(); Nmu;+{19M  
} YB?yi( "yL  
input.close(); J" :R,w`  
} ;;|S QX  
catch(IOException e){e.printStackTrace ();} =@BVO@z@  
catch(Exception e){e.printStackTrace ();} W>[0u3  
} ;J<K/YdI  
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private void processErrorCode(int nErrorCode) 5MU-Eu|*>  
{ dZ]['y%  
System.err.println("Error Code : " + nErrorCode); e0rh~@E  
} Qy< ~{6V  
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//停止文件下载 /XEt2,sI9  
public void siteStop() qRk<1.  
{ ~\uI&S5  
bStop = true; R1A|g=kF  
for(int i=0;i<nStartPos.length;i++) z''ITX)oG  
fileSplitterFetch.splitterStop(); $"#2hVO  
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} 04npY+1 8%  
} -l)u`f^n|  
//负责部分文件的抓取 Q:rQ;/b0/  
**FileSplitterFetch.java Xx)PyO  
*/ G%Dhj)2}  
package NetFox; LHJ}I5zv  
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import java.io.*; ePD~SO9*  
import java.net.*; '+8`3['  
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public class FileSplitterFetch extends Thread { TDqH"q0  
)7`2FLG  
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String sURL; //File URL o'#ow(X  
long nStartPos; //File Snippet Start Position A.[~}ywH  
long nEndPos; //File Snippet End Position eW"L")  
int nThreadID; //Thread's ID S8_>Lw  
boolean bDownOver = false; //Downing is over G&7!3u  
boolean bStop = false; //Stop identical qHQWiu%h  
FileAccessI fileAccessI = null; //File Access interface ;^yR,32F  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException JSf \ApX  
{ 3]z%C'  
this.sURL = sURL; u[Ij4h.  
this.nStartPos = nStart; %]U'   
this.nEndPos = nEnd; 8Pgw_ 21N1  
nThreadID = id; PjxZ3O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 SO!|wag$  
} "bhF`,V  
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public void run() q eW{Cl~  
{ [>MPM$9F-m  
while(nStartPos < nEndPos && !bStop) /RF=8,A  
{ m N&G  
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}  
try{ zyh #ygH  
URL url = new URL(sURL); kiP-^Wan  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,SVl>~!  
httpConnection.setRequestProperty("User-Agent","NetFox"); -%
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String sProperty = "bytes="+nStartPos+"-"; O/{X:Ja{  
httpConnection.setRequestProperty("RANGE",sProperty); Mtw7aK  
Utility.log(sProperty); "kdmqvTHK0  
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InputStream input = httpConnection.getInputStream(); 26K sP .-  
//logResponseHead(httpConnection); |mS-<e8LY4  
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byte[] b = new byte[1024]; P #PRzt  
int nRead; K6BP~@H_D  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }M0GPpv  
{ g]mR
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nStartPos += fileAccessI.write(b,0,nRead); x 8_nLZ  
//if(nThreadID == 1) *y
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C)z?-f  
} 7A=*3  

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Utility.log("Thread " + nThreadID + " is over!"); ]iq2_{q  
bDownOver = true; ag*5fBF  
//nPos = fileAccessI.write (b,0,nRead); Y<WA-d
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} .{8?eze[m  
catch(Exception e){e.printStackTrace ();} XusTU  
} T=W;k<P
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} s`
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//打印回应的头信息 HB0DG<c-  
public void logResponseHead(HttpURLConnection con) Cx[Cst`  
{ Rk$  
for(int i=1;;i++)
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{ d"nms\=p  
String header=con.getHeaderFieldKey(i); +N>z|T<  
if(header!=null) *~%QXNn`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :|z.F+-/
 
Utility.log(header+" : "+con.getHeaderField(header)); =cwdl7N&I  
else ~:xR0dqx  
break; `=.A])>  
} k>V~iA  
} l2h1CtAU  
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public void splitterStop() N2
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{ OTmw/#ug  
bStop = true; z[?
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} G|eJ
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} nYE''g+x  
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o ?`LZd:{  
/* jFH wu*  
**FileAccess.java m2j]wUh"  
*//文件访问(定位，写)
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package NetFox; d cG)ql4d  
import java.io.*; %h9'kJzNk  
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*!c&[
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public class FileAccessI implements Serializable{ {;^GKb+  
1>'xmp+#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -E+LA  
RandomAccessFile oSavedFile; ?Hrj}K27  
long nPos; m+=L}[  
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public FileAccessI() throws IOException mFx\[S  
{ R\Of ,  
this("",0); r-'CB  
} Xwz'h;Ks_  
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public FileAccessI(String sName,long nPos) throws IOException 9?Q0O\&uP  
{ E(miQ  
oSavedFile = new RandomAccessFile(sName,"rw"); #8CeTR23cw  
this.nPos = nPos; d]I3zSIC  
oSavedFile.seek(nPos); i~i ?M)  
} >mUSRf4  
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public synchronized int write(byte[] b,int nStart,int nLen)
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{ l",X  
int n = -1; 16|miK[@  
try{ iL8:I)z  
oSavedFile.write(b,nStart,nLen); n h&[e  
n = nLen; Rl[SqmnI)@  
} kR]AW60OE  
catch(IOException e) 2=`}:&0l  
{ ]r@CmwC  
e.printStackTrace (); _`d=0l*8  
} %Y-KjSs+l  
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return n; #'fQx`LV  
} a?]~Sw"@  
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} ~aL&,
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/* 8umW>  
**SiteInfoBean.java (RafidiH  
*/ abtYa  
package NetFox; byN4?3F  
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public class SiteInfoBean { +Cs.v.GA5  
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private String sSiteURL; //Site's URL ot; ]?M  
private String sFilePath; //Saved File's Path SS7C|*-
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private String sFileName; //Saved File's Name $m
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private int nSplitter; //Count of Splited Downloading File 5-.{RU=  
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public SiteInfoBean() Ur,{ZGm  
{//nSplitter的缺省值为5 "VI2--%v3  
//default value of nSplitter is 5 r[4dGt  
this("","","",5); ,nGZ(EBD  
} K'zBDrkW-x  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :IRQouTf:,  
{ TLT6z[  
sSiteURL= sURL; ~4=XYYcka  
sFilePath = sPath; ZL+46fj  
sFileName = sName; G4{TJ,~  
this.nSplitter = nSpiltter; !HSX:qAP$  
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} ?V$@2vBVX4  
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public String getSSiteURL() K?gO]T{6  
{ #|;;>YnZ  
return sSiteURL; y2:Bv2}  
} Igb%bO_  
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public void setSSiteURL(String value) ku^0bq}BrH  
{ z18<rj  
sSiteURL = value; IIUTo  
} XBN,{  
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public String getSFilePath() *#
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{ F:'>zB]-}  
return sFilePath; 2,e>gP\]  
} 7da~+(yhr  
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public void setSFilePath(String value) q|S,^0cU  
{ f1X]zk(=W  
sFilePath = value; ?7Skk  
} ]6;oS-4gu?  
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public String getSFileName() .y2np  
{ 4]m?8j) 6b  
return sFileName; r)Fd
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} A1
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public void setSFileName(String value) y0\=F  
{ h45RwQ5Z  
sFileName = value; =`MMB|{6  
} ?Y'r=Q{w  
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public int getNSplitter() O^<\]_l  
{ 3y]rhB  
return nSplitter; cPg$*,]  
} 7&*d]#&~j  
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public void setNSplitter(int nCount) Ujfs!ikh&F  
{ [J+]1hCZ|  
nSplitter = nCount; "Tc[1{
eI  
} M =6  
} E9#.!re|^  
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K?X 6@u|h  
/* R\:t 73  
**Utility.java t2#zQ[~X!  
*/ 3?-2~s3gp  
package NetFox; =(Wl'iG   
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public class Utility { zZI7p[A[3  
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public Utility() zJT,Hv .  
{ Qm2(Z8Gh  
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} p5 )+R/  
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//线程睡眠 kf2e-)uUs  
public static void sleep(int nSecond) x(bM   
{ (5&l<u"K~  
try{ )`-vN^1S-  
Thread.sleep(nSecond); of>}fJ_p  
} H
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catch(Exception e) 6I~{~YvB"  
{ H <ugc  
e.printStackTrace (); e3x;(@j  
} {6brVN.V  
} }I ^e:,{  
H`Ld,E2ex&  
//日志 r:9H>4m  
public static void log(String sMsg) Wkc^?0p  
{ VO+3@d:  
System.err.println(sMsg); ["XS|"DM  
} 8,YxCm ie  
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public static void log(int sMsg) $-;x8O]u  
{ A3mSSc6  
System.err.println(sMsg); k80!!S=_>  
} ;P2(C >|  
} <]kifiN#  
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/* 2mVLR;s{_  
**TestMethod.java ~ZXAW~a}  
*/ Q5pm^X._j  
package NetFox; W.VyH|?  
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public class TestMethod {
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public TestMethod() .Wq"  
{ ///xx/weblogic60b2_win.exe ~L=Idt!9  
try{ jj*e.t:F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); wO3K2I]>0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /e4#DH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PbN"+qM  
fileFetch.start(); 3+| {O  
} ]z_C7Y"4BR  
catch(Exception e){e.printStackTrace ();}
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} Il,^/qvIY  
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public static void main(String[] args) qvhol  
{ RXU#.=xvy  
new TestMethod(); 7]6HXR@  
} A1nEp0%Y  
} M/^kita  
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