http断点续传简单实现（java)

/* F+vgkqs@9  
**SiteFileFetch.java w'q}aQS  
*/ XUUl*5^  
package NetFox; &6/# O  
import java.io.*; 4ze-N8<[  
import java.net.*; =K#D^c~  
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public class SiteFileFetch extends Thread { 3=!\>0;E-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean |F36^  
long[] nStartPos; //开始位置 q#Y%Y  
long[] nEndPos; //结束位置 62&E]>A(i  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4/S% eZB  
long nFileLength; //文件长度 ya]CxnKR3  
boolean bFirst = true; //是否第一次取文件 A{Giz&p  
boolean bStop = false; //停止标志 DSyfF&uC  
File tmpFile; //文件下载的临时信息 4{rwNBj(  
DataOutputStream output; //输出到文件的输出流 Pj_2y)^?  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \D BtU7"v  
public SiteFileFetch(SiteInfoBean bean) throws IOException g7k|Ho-W  
{ (3C6'Wt  
siteInfoBean = bean; 3O<:eS~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `[V]xP%V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); R;6(2bTN6  
if(tmpFile.exists ()) 6\(wU?m'/  
{ %s~MfK.k  
bFirst = false; [3++Q-rR=  
read_nPos(); ZK))91;v  
} wmFI?   
else #5)E4"m  
{ "Ko^m(`  
nStartPos = new long[bean.getNSplitter()]; z.{T`Pn  
nEndPos = new long[bean.getNSplitter()]; MyAS'Ki  
} /N+*=LIK I  
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} oDul ?%  
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public void run() '7Dg+a^x7  
{ P?*$Wf,~n  
//获得文件长度 ;X6FhQ;{*0  
//分割文件 I,D24W4l  
//实例FileSplitterFetch -~eNC^t;W  
//启动FileSplitterFetch线程 !+&"y K@J  
//等待子线程返回 \{L!hAw  
try{ WE\912j  
if(bFirst) D`3m%O(?  
{ {:c*-+?  
nFileLength = getFileSize(); YuD2Q{  
if(nFileLength == -1) F!jYkDY  
{ *+h2,Z('a  
System.err.println("File Length is not known!"); |cL'4I>b9  
} tF SO"  
else if(nFileLength == -2) %..{c#V  
{ H27_T]\  
System.err.println("File is not access!"); R[5*]$(b  
} A:F*Y%ZW  
else \?&P|7N  
{ +N2?fgA  
for(int i=0;i<nStartPos.length;i++) dK,j|  
{ 0EfM~u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,g%2-#L%  
} {E!ie{~  
for(int i=0;i<nEndPos.length-1;i++) k'Fc:T8:~5  
{ Be"D0=<  
nEndPos = nStartPos[i+1]; =mYY8c Yl  
} )s1W)J?8  
nEndPos[nEndPos.length-1] = nFileLength; tsR\cO~/  
} F>E'/r*  
} jgbUZP4J>  
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//启动子线程 !]4'f/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;>Y,b4B;  
for(int i=0;i<nStartPos.length;i++) ,%e.nj9  
{ s QfP8}U  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a)GLz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *A.E?9pL\  
nStartPos,nEndPos,i); HcwqVU  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %,$/wh)<V  
fileSplitterFetch.start(); ^il'
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} ]&w>p#_C  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), si,fs%D&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3{ i'8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +[Nc";Oy  
nEndPos = " + nFileLength); qT^R>p  
// fileSplitterFetch[nPos.length-1].start(); ta_!  
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//等待子线程结束  M]:4X_  
//int count = 0; >t')ZSjRs  
//是否结束while循环 :<f7;.  
boolean breakWhile = false; K?:rrd=7q  
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while(!bStop) EaGh`*"w(7  
{ c*$&MCh  
write_nPos();  bz'V
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Utility.sleep(500); jd
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breakWhile = true; B'>(kZYMs  
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for(int i=0;i<nStartPos.length;i++) SDpaW6(_  
{ _]H$rf,Rc  
if(!fileSplitterFetch.bDownOver) IM),cOp=  
{ )?RR1P-ID  
breakWhile = false; o,(MB[|hQ  
break; (5rH72g(  
} 4tU3+e5h  
} 2i`N26On  
if(breakWhile) H5uWI  
break; 6O8'T`F[  
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//count++; i&\N_PUm[  
//if(count>4) 5fuOl-M0W  
// siteStop(); DJP)V8]!B  
} ~.7r  
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System.err.println("文件下载结束！"); 52K_kB5  
} +[M5x[[$  
catch(Exception e){e.printStackTrace ();} ;|&Ak_I2G  
} YFgQ!\&59  
*.4;7#  
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//获得文件长度 289teU  
public long getFileSize() n.P$7%G`2  
{ {t`UV,  
int nFileLength = -1; (cJb/|?3  
try{ F }l_=  
URL url = new URL(siteInfoBean.getSSiteURL()); Kg^L 4Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q@1!v  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZOvMA]Rf  
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int responseCode=httpConnection.getResponseCode(); Ex^|[iV  
if(responseCode>=400) 6U)Lhf\'o  
{ "MZj}}l  
processErrorCode(responseCode); ;Q>(%"z};  
return -2; //-2 represent access is error m:A7*r[  
} tgEXX-{  
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String sHeader; pv1J6  
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for(int i=1;;i++) %cJ]Ds%V  
{ @q2If{Tk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]>-#T  
//Utility.log(in.readLine()); %tiFx:F+  
sHeader=httpConnection.getHeaderFieldKey(i); HI6;=~[  
if(sHeader!=null) (wLzkV/6  
{ }<`Mn34@  
if(sHeader.equals("Content-Length")) 0Pw?@uV  
{ =+`I%>wc  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R06q~>  
break; Qag@#!&n  
} E8#r<=(m  
} so_  
else +o})Cs`|=A  
break; g(m3 &  
} \NwL#bQ~  
} mle"!*  
catch(IOException e){e.printStackTrace ();} [I:D\)$<  
catch(Exception e){e.printStackTrace ();} 2^N 4(
 
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Utility.log(nFileLength); ma.yI};
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return nFileLength; `vWFTv  
} xq1=O  
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|Q2H^dU'rQ  
//保存下载信息（文件指针位置） &z;F'>"  
private void write_nPos() /]4[b!OTJ  
{ aW$(lf2;  
try{ $FUWB6M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }.w@. S"  
output.writeInt(nStartPos.length); Q-78B'!=  
for(int i=0;i<nStartPos.length;i++) 7KU/ 1l9$9  
{ b489sa  
// output.writeLong(nPos); QZ(se  
output.writeLong(fileSplitterFetch.nStartPos); (5S(CYls  
output.writeLong(fileSplitterFetch.nEndPos); p\5DW'  
} O@St^o*A}  
output.close(); A`2l;MW  
} ~9#[\/;"  
catch(IOException e){e.printStackTrace ();} 9Cbf[\J!bq  
catch(Exception e){e.printStackTrace ();} aLapb5VV  
} l%]S7|PKx  
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//读取保存的下载信息（文件指针位置） y1P KoN|K  
private void read_nPos() `iuo([E d  
{ }ybveZxv5A  
try{ @+1-_Q`s/R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Mrpn^C2)  
int nCount = input.readInt(); !7XAc,y  
nStartPos = new long[nCount]; Z!o&};_j  
nEndPos = new long[nCount]; \9*wo9cV  
for(int i=0;i<nStartPos.length;i++) ImQ?<g8$  
{ X,d`-aKO\y  
nStartPos = input.readLong(); xFcJyjo^z  
nEndPos = input.readLong(); S;[g0j  
} i_8q!CL@{  
input.close(); A9^t$Ii  
} bQc-ryC+.  
catch(IOException e){e.printStackTrace ();} yZFm<_9>  
catch(Exception e){e.printStackTrace ();} [U[saR\  
} #xZ7%   
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private void processErrorCode(int nErrorCode) apQ` l^  
{ 7A@GNA  
System.err.println("Error Code : " + nErrorCode); 0X =Yly*m@  
} & xOEp  
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//停止文件下载 td{M%D,R"  
public void siteStop() nE+OBdl  
{ tM3eB= .*  
bStop = true; D4WvRxki  
for(int i=0;i<nStartPos.length;i++) kx=.K'd5H  
fileSplitterFetch.splitterStop(); Cw"Y=`  
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} Y(QLlJ*)/  
} Ia-`x/r*m  
//负责部分文件的抓取 E'qGKT  
**FileSplitterFetch.java >g8H  
*/ D.?Rc'yD  
package NetFox; 9C[i#+_3M  
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import java.io.*; b,U"N-6  
import java.net.*; ./nq*4=  
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public class FileSplitterFetch extends Thread { hd*bPj;  
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String sURL; //File URL 6}bUX_!&s  
long nStartPos; //File Snippet Start Position b z3&  
long nEndPos; //File Snippet End Position `BA wef  
int nThreadID; //Thread's ID K cI'P(
 
boolean bDownOver = false; //Downing is over E
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boolean bStop = false; //Stop identical T0Lh"_X3  
FileAccessI fileAccessI = null; //File Access interface JD1IL` ta;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 'lwLe3.c  
{ ];X[xs  
this.sURL = sURL; F!m/n!YR  
this.nStartPos = nStart; 0c*y~hUVZ  
this.nEndPos = nEnd; RzG7Xr=t  
nThreadID = id; Z9rmlVU6!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $*EK v'g[n  
} d
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public void run() 3(D!]ku~
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{ KG:CVIW Y  
while(nStartPos < nEndPos && !bStop) rXR=fj= 2  
{ NYopt?Xg  
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try{ HmxA2 ~C  
URL url = new URL(sURL); I75>$"$<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .ET@J`"M  
httpConnection.setRequestProperty("User-Agent","NetFox"); $kPC"!X\  
String sProperty = "bytes="+nStartPos+"-"; >|h$d:~n  
httpConnection.setRequestProperty("RANGE",sProperty); 8BP.VxX  
Utility.log(sProperty); Ak(_![Q:q\  
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InputStream input = httpConnection.getInputStream(); ('yBIb\ue  
//logResponseHead(httpConnection); MVe:[=VOT|  
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byte[] b = new byte[1024]; Y![m'q}K  
int nRead; d8l T+MS=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $ {29[hO  
{ |ymw
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nStartPos += fileAccessI.write(b,0,nRead); ke$g[g  
//if(nThreadID == 1) t[>y=89
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1
u4)  
} R%7* )3$&r  
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# `}(x;ge  
Utility.log("Thread " + nThreadID + " is over!"); !brXQj8D7  
bDownOver = true; H(}Jt!/:  
//nPos = fileAccessI.write (b,0,nRead); QoagyL  
} 92y<E<n  
catch(Exception e){e.printStackTrace ();} Rw8l"`  
} 9='a9\((mH  
} a:$h
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v X=zqV  
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//打印回应的头信息 Aj|Gqw>  
public void logResponseHead(HttpURLConnection con) e)
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{ C*O648yz[  
for(int i=1;;i++) 
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{ !YJfP@"e6r  
String header=con.getHeaderFieldKey(i); X}XTEk3[  
if(header!=null) 6 <&jY  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t^N 92$|  
Utility.log(header+" : "+con.getHeaderField(header)); %Ot2bhK;  
else IB~`Ht8 b  
break; uL`6}0  
} >eF4YZ"  
} \1k(4MWd  
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public void splitterStop() 8=XfwwWHy<  
{ +n#kpi'T  
bStop = true; WJCh{Xn%*  
} uK_Q l\d  
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} v.eN
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/* bwHl}3  
**FileAccess.java G8Hj
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*//文件访问(定位，写) ] T`6Hz!  
package NetFox; JPeZZ13sS  
import java.io.*; CHeU`!:  
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public class FileAccessI implements Serializable{ DyZe+,g;S  
=_(i#}"A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |$$gj[+^  
RandomAccessFile oSavedFile; #. mc+n:I  
long nPos; m53XN  
r&^LSTU0!  
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public FileAccessI() throws IOException 3$cIm+  
{ >0#WkmRY  
this("",0); \tL9`RKpg  
} Z_%9LxZlyj  
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public FileAccessI(String sName,long nPos) throws IOException hqEnD  
{ )9(Mt_  
oSavedFile = new RandomAccessFile(sName,"rw"); v=-8} S  
this.nPos = nPos; |
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oSavedFile.seek(nPos); -Oj}PGj$e\  
} +59tX2@Q  
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public synchronized int write(byte[] b,int nStart,int nLen) #2N']VP  
{ 2&L2G'  
int n = -1; k91ctEp9>  
try{ R-lB.9e#M  
oSavedFile.write(b,nStart,nLen); z]P=>w  
n = nLen; -,;r %7T  
} *-KgU'u?  
catch(IOException e) cmw2EHTT<  
{ VBHDI{HzRv  
e.printStackTrace (); v%mAU3M  
} 1e Wl:S}  
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return n; RbexsBq  
} 3*N-@;[>b  
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fn
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}
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/* Pfy2PpA  
**SiteInfoBean.java |AY`OVgcKD  
*/ y)`f$Hl@1  
package NetFox; -2)6QKh~D  
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*'b3Z3c,;  
public class SiteInfoBean { &&(^;+  
3<5E254N  
P>*B{fi^  
private String sSiteURL; //Site's URL *aE/\b  
private String sFilePath; //Saved File's Path Y)X 'hk)5|  
private String sFileName; //Saved File's Name
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private int nSplitter; //Count of Splited Downloading File PEKU  
0?]Y^:  
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public SiteInfoBean() J>H$4t#HX  
{//nSplitter的缺省值为5 i{#5=np H  
//default value of nSplitter is 5 ^jY'Hj.Bs  
this("","","",5); jgc
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} (MI8Kkb1d  
i|- 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g{t)I0xm  
{ 1qEpQ
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sSiteURL= sURL; MfX1&/Z+  
sFilePath = sPath; {8'f>YP  
sFileName = sName; ; O6Ez-"  
this.nSplitter = nSpiltter; R)p+#F(s  
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}
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public String getSSiteURL() *]L(,_:"  
{ F&ud|X=m  
return sSiteURL; -r.Qy(}p  
} .7h:/d Y:  
7Ya4>*B  
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public void setSSiteURL(String value) 3WOm`<  
{ #FAy ]7/O  
sSiteURL = value; /S}4J"  
} W@X/Z8.(  
v;S_7#  
q%G"P*g$(  
public String getSFilePath() t`b!3U>I  
{ .ZV-]jgr  
return sFilePath; q_5hKipd\b  
} h
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=/ b2e\  
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public void setSFilePath(String value) kOu C@~,  
{ 1MntTIT  
sFilePath = value; ^)qOILn  
} NuL.l__W  
}bU1wIW9I  
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public String getSFileName() (%bqeI!ob  
{ )D_\~n/5  
return sFileName; 5:oteNc
3  
} =vd9mb-  
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public void setSFileName(String value) TzPG(f  
{ 8ZnHp~  
sFileName = value; nfL-E:n=  
} kjS9?>i  
5,i0QT"  
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public int getNSplitter() ~>j5z&:&  
{ qs9q{n-Aj  
return nSplitter; LqDj4[}  
} )z:"P;b"Nl  
&l&B[s6[  
nm8XHk]
  
public void setNSplitter(int nCount) <-Hw@g  
{ >Y3ZK{b  
nSplitter = nCount; aMLtZ7i>  
} >[$j(k
^  
} +dw=
)A#/  
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+\Zr\fOe|%  
/* u{Rgk:bn  
**Utility.java ees^
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*/ eu^B  
package NetFox; PQ}owEJ2eM  
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public class Utility { *(w#*,lv  
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6 _Cc+}W  
public Utility() Xy[*)<  
{ oMw#ROsvC  
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}  f^vz  
y%wjQC 0~  
//线程睡眠 ,cF $_7M  
public static void sleep(int nSecond) u A=x~-I  
{ xGBp+j1H  
try{ B]_NI=d  
Thread.sleep(nSecond); ]ssX,1#Xh  
} }
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catch(Exception e) K'DRX85F  
{ Ln3<r&&Jz  
e.printStackTrace (); C8oAl3d+h  
} 5(qc_~p^  
} &4 ~C%{H3  
`#Yv(a2TY  
//日志 V=+wsc  
public static void log(String sMsg) k%-S7iQ  
{ ww^!|VVa  
System.err.println(sMsg); &>KZ4%&?  
} 0Xe?{!@a  
:tTP3t5  
\c .^^8r  
public static void log(int sMsg) 'v42QJ"{  
{ tl@n}   
System.err.println(sMsg); =eB^(!M  
} \0'0)@uziQ  
} [\|p~Qb)s  
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(vXes.|+t  
/* y(2Fa
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**TestMethod.java ^j)0&}fB  
*/ 6.0/asN}  
package NetFox; !=t.AgmL  
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public class TestMethod { y wf@G; fK  
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public TestMethod() Lfj]Y~*z  
{ ///xx/weblogic60b2_win.exe Ic,V,#my  
try{ /^jV-Z`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w<54mGMOLr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9-6E(D-ux  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ta)'z@V@g  
fileFetch.start(); x]X!nx6G  
} PRpW*#"EI  
catch(Exception e){e.printStackTrace ();} qEW3k),  
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} sfuA {c'v  
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6Pzz= ai<  
public static void main(String[] args) d_r1}+ao  
{ 54geU?p0  
new TestMethod(); ns/L./z  
} =u,8(:R]s  
} nxZ[E.-\  
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