http断点续传简单实现（java)

/* 2 mjV
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**SiteFileFetch.java UO`;&e-DB  
*/ x90*yaw>h  
package NetFox; :)f7A7:;  
import java.io.*; pfuW  
import java.net.*; Lr;(xw\[
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public class SiteFileFetch extends Thread { EfLO5$?rm  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^yviV Y  
long[] nStartPos; //开始位置 10Wz,vW,n  
long[] nEndPos; //结束位置 ]T! }XXK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #1'\.v  
long nFileLength; //文件长度 a[bBT@f  
boolean bFirst = true; //是否第一次取文件 YO)$M-]>%J  
boolean bStop = false; //停止标志 AT Zhr. H  
File tmpFile; //文件下载的临时信息 AZ|yX  
DataOutputStream output; //输出到文件的输出流 ,"
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &>WWzikB*  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2Tav;LKX  
{ pVp:@0h  
siteInfoBean = bean; `i~ Y Fr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); x LBQ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6Sj6i^"  
if(tmpFile.exists ()) ',7??Q7j&v  
{ ?VU(Pq*`  
bFirst = false; .k{ j]{k  
read_nPos(); u#7+U\  
} Q~D`cc|]  
else IHfzZHy  
{ `L;eba  
nStartPos = new long[bean.getNSplitter()]; @\_x'!R  
nEndPos = new long[bean.getNSplitter()]; l*b)st_p%  
} PQW(EeQ  
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} >Y 1{rSk  
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public void run() yj6@7@l>A  
{ rI$`9d  
//获得文件长度 `pZs T ^G[  
//分割文件 %wV>0gQTf  
//实例FileSplitterFetch }H4=HDO  
//启动FileSplitterFetch线程 G}@#u9  
//等待子线程返回 j Ib  
try{ DH DZ_t:  
if(bFirst) eg"Gjp-4=  
{ _zxLwU1(x  
nFileLength = getFileSize(); ulHn#)  
if(nFileLength == -1) 8 S`9dSc  
{ .N4  
System.err.println("File Length is not known!"); .UCt|> $  
} egR9AEJvz  
else if(nFileLength == -2)
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{ s}&bJ"!Z  
System.err.println("File is not access!"); RIM`omM  
} g o5]<4`r  
else F-(dRSDNM  
{ T`/IO.2  
for(int i=0;i<nStartPos.length;i++) SDG-~(Y  
{ x)rlyjFM  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ? Q@kg  
} PMsz`  
for(int i=0;i<nEndPos.length-1;i++) XB hb`AG  
{ @Fv=u  
nEndPos = nStartPos[i+1]; ){s*n=KIO  
} :Br5a34q  
nEndPos[nEndPos.length-1] = nFileLength; <O?y-$~  
} ;cQW sTfT  
} _,Fny_u=;  
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//启动子线程 A\rt6/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <HWS:'1  
for(int i=0;i<nStartPos.length;i++) @4~=CV%j  
{ Dq\ Jz~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J`M&{UP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |XY
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nStartPos,nEndPos,i); eC DIwB28  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8GPIZh'0h  
fileSplitterFetch.start(); c;f!!3&  
} Z!d7&T}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m4K* <  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "\"DCDKmG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |as!Ui/J/  
nEndPos = " + nFileLength); S&O3HC  
// fileSplitterFetch[nPos.length-1].start(); p]D]: Z}P  
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//等待子线程结束 s6*ilq1  
//int count = 0; .%EL\2  
//是否结束while循环 Rx07trfN  
boolean breakWhile = false; =*BIB
5  
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while(!bStop) Mvj;ic6iK  
{ H?1xjY9sl  
write_nPos();
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Utility.sleep(500); *F^wtH`  
breakWhile = true; 9L0GLmLk1u  
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for(int i=0;i<nStartPos.length;i++) ~8 H_u  
{ +1JH  
if(!fileSplitterFetch.bDownOver) p1pQU={<  
{ u*S=[dq  
breakWhile = false; qIUfPA=/_  
break; %A1@&xrbl  
} 6\7ncFO3  
} gie
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if(breakWhile) Z0!5d<  
break; L(S'6z~_9  
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//count++; y
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//if(count>4) z@|dzvjl Q  
// siteStop(); 'z@0  
} Kr'f-{  
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System.err.println("文件下载结束！"); in <(g@Zg  
} $\o{_?}1  
catch(Exception e){e.printStackTrace ();} DDT_kK;  
} xp'_%n~K@  
}UJv[  
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//获得文件长度 %t=kdc0=_  
public long getFileSize() +i ?S  
{ sKz`aqI  
int nFileLength = -1; >%p{38  
try{ !1T\cS#1%  
URL url = new URL(siteInfoBean.getSSiteURL()); MfO:m[s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7`vEe'qz  
httpConnection.setRequestProperty("User-Agent","NetFox"); CQ7{1,?2  
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2 ]H6G$M  
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int responseCode=httpConnection.getResponseCode(); e:E0"<  
if(responseCode>=400) 'oNO-)p\#!  
{ DBLk!~IF  
processErrorCode(responseCode); *,C(\!b !?  
return -2; //-2 represent access is error 7 J^rv9i4  
} mvW%  
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String sHeader; # ?1Sm/5k`  
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for(int i=1;;i++) 2n><RZ/9  
{ =@Dwlze  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); I4;A8I  
//Utility.log(in.readLine()); 3K&4i'}V  
sHeader=httpConnection.getHeaderFieldKey(i); 84HUBud76Y  
if(sHeader!=null) c0c|z Ym  
{ ^m#-9-`  
if(sHeader.equals("Content-Length")) R_]{2~J+  
{ iUMY!eqp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K/m3  
break; VUTacA Y>L  
} /-zXM;h  
} hc (e$##  
else 0.$hn  
break; rWys'uc  
} &uP~rEJl+  
} o)6pA^+  
catch(IOException e){e.printStackTrace ();} h1 WT
  
catch(Exception e){e.printStackTrace ();} sAo& uZ  
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Utility.log(nFileLength); WPZ?*Sx  
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return nFileLength; kP#e((f,  
} R(.}C)q3  
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//保存下载信息（文件指针位置） }(a+aHH  
private void write_nPos() AE: Z+rM*  
{ ]v[|B  
try{ Nu8Sr]p  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2._X|~0a  
output.writeInt(nStartPos.length); _'4A|-9  
for(int i=0;i<nStartPos.length;i++) NmK8<9`u  
{ wB'zuPAK6  
// output.writeLong(nPos); 6
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output.writeLong(fileSplitterFetch.nStartPos); xI,2LGO  
output.writeLong(fileSplitterFetch.nEndPos); Ehzo05/!  
} 2|\A7.  
output.close(); &`b "a!  
} d0'JC*  
catch(IOException e){e.printStackTrace ();} '|;X0fD  
catch(Exception e){e.printStackTrace ();} TJE\A)|>g  
} [c_|ob]  
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//读取保存的下载信息（文件指针位置） 2r$#m*  
private void read_nPos() IwGqf.!.>  
{ $R<Me  
try{ :akT 'q#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .ROznCe}  
int nCount = input.readInt(); v}WR+)uFQ  
nStartPos = new long[nCount]; :Hxv6  
nEndPos = new long[nCount]; .^J2.>.  
for(int i=0;i<nStartPos.length;i++) MX>[^
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{ `1:{0p2q  
nStartPos = input.readLong(); *<1r3!  
nEndPos = input.readLong(); @aJ
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} EpQ8a[<-3  
input.close(); `3p~m,  
} <dyewy*.L  
catch(IOException e){e.printStackTrace ();} 12Y  
catch(Exception e){e.printStackTrace ();} 1+?^0%AC  
} hsu{eyp  
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private void processErrorCode(int nErrorCode) Dk48@`l2  
{ .`?@%{  
System.err.println("Error Code : " + nErrorCode); IK*07h/!  
} vn/.}GkpU  
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//停止文件下载 :[;hu}!&  
public void siteStop() [w ;kkMJAy  
{ \h8
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bStop = true; -G6U$  
for(int i=0;i<nStartPos.length;i++) Ty
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fileSplitterFetch.splitterStop(); g^zs,4pPU<  
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} UA|u U5Q  
} HSq}7S&U  
//负责部分文件的抓取 A 7[:5$  
**FileSplitterFetch.java 'vNG(h#%d  
*/ )8
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package NetFox; A$6$,h  
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import java.io.*; EJ2yO@5O  
import java.net.*; <FZ@Q[RP  
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public class FileSplitterFetch extends Thread { },|M9I0  
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String sURL; //File URL T0]MuIJ).  
long nStartPos; //File Snippet Start Position _V`DWR *  
long nEndPos; //File Snippet End Position JU&+c6>  
int nThreadID; //Thread's ID g}]t[}s1]  
boolean bDownOver = false; //Downing is over # W"=ry3{  
boolean bStop = false; //Stop identical ?6'rBH/w  
FileAccessI fileAccessI = null; //File Access interface rj!0GI  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qe5feky  
{ J=/5}u_gw  
this.sURL = sURL; *2jK#9"MP  
this.nStartPos = nStart;
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this.nEndPos = nEnd; 6-O_\Cq8  
nThreadID = id; bJs9X/E  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _YRE (YZ/  
} ,a#EW+" Z  
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public void run() ;| 1$Q!4  
{ $8BPlqBIZ  
while(nStartPos < nEndPos && !bStop) i~r l o^  
{ r7qh>JrO  
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try{ }NB}"%2  
URL url = new URL(sURL); B$Kn1 k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bV"G~3COy  
httpConnection.setRequestProperty("User-Agent","NetFox"); p)+k=b  
String sProperty = "bytes="+nStartPos+"-"; cph:y  
httpConnection.setRequestProperty("RANGE",sProperty); NFv>B>  
Utility.log(sProperty); n'emNRa  
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InputStream input = httpConnection.getInputStream(); 4!KoFoZt*  
//logResponseHead(httpConnection); =JmT:enV  
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byte[] b = new byte[1024]; {AQ=<RDRF  
int nRead; X]'7Ov  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,~._}E&9I  
{ %;D.vKoh  
nStartPos += fileAccessI.write(b,0,nRead); 7x<i :x3  
//if(nThreadID == 1) jRatm.N  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LW(6$hpPp  
} bcupo:N  
n93=8;&  
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Utility.log("Thread " + nThreadID + " is over!"); TjG4`:*y#m  
bDownOver = true; aFLO{tr`  
//nPos = fileAccessI.write (b,0,nRead); ~ar=PmYV7  
} :<|<|qJWo  
catch(Exception e){e.printStackTrace ();} `He,p -  
} 1x,tu}<u^  
} +sJrllrE(  
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//打印回应的头信息 ZzX~&95G  
public void logResponseHead(HttpURLConnection con) n?c]M  
{ &zo|Lfe  
for(int i=1;;i++) Sfr&p>{,  
{ @/1w4'M  
String header=con.getHeaderFieldKey(i); iJ~Vl"|m  
if(header!=null) D:K4H+ch  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); nWHa.H#  
Utility.log(header+" : "+con.getHeaderField(header)); =lpQnj
"  
else @K!&qw  
break; !Ta>U^7  
} 1</kTm/Qa  
} [ I/<_AT#  
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public void splitterStop() m1*O0Tg]"  
{ }m-FGk  
bStop = true; '{B!6|"X  
} ~^cMys |'  
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} 1PatH[T[  
{,L+1h  
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/* )[Yv?>ib  
**FileAccess.java 2rZxSg  
*//文件访问(定位，写) ,tg0L$qC  
package NetFox; &ZQJ>#~j^  
import java.io.*; ~_!F0
1s  

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public class FileAccessI implements Serializable{ mbueP.q[?  
>&U,co$>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ',S'.U  
RandomAccessFile oSavedFile; JGQjw(Xs  
long nPos; *H|M;G  
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public FileAccessI() throws IOException >_LDMs[-p  
{ T'b_W,m~,u  
this("",0); =*LS%WI  
} %x} O1yV  
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public FileAccessI(String sName,long nPos) throws IOException s S7c!  
{ E^S
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oSavedFile = new RandomAccessFile(sName,"rw"); L5\WpM=  
this.nPos = nPos; \(vY%DL1:  
oSavedFile.seek(nPos); v 7x:dcV  
} N~xLu8,  
X'
"SVO.  
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public synchronized int write(byte[] b,int nStart,int nLen) }_68j8`  
{ j+ LawW-  
int n = -1; ih;]nJ]+-  
try{ ,1"KHv  
oSavedFile.write(b,nStart,nLen); _"w2Uq  
n = nLen; "l*`>5Nn9  
} `kJ^zw+  
catch(IOException e) `{xNXH]@  
{ +o51x'Ld*  
e.printStackTrace (); O7$hYk  
} t0T"@t#c  
m RO~aD!N  
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return n; (#E.`e1#6  
} 4tS.G  
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} d:U9pC$  
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#gcF"L||  
/* =Yt R`  
**SiteInfoBean.java '&|=0TDd+  
*/ _Iv6pNd/  
package NetFox; %$Aqle[  
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public class SiteInfoBean { sK5r$Dbr  
a)'5Nw9*  
%&Q$dzgb_  
private String sSiteURL; //Site's URL aWY g
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private String sFilePath; //Saved File's Path _&b4aW9<  
private String sFileName; //Saved File's Name 4sT88lG4n  
private int nSplitter; //Count of Splited Downloading File HZf/CE9T  
'4#}e[e  
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public SiteInfoBean() 3z&Fi;<+j  
{//nSplitter的缺省值为5 "UJ S5[7$  
//default value of nSplitter is 5 & J2M1z%  
this("","","",5); cu/5$m?xx  
} 9*1,!%]  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u[ Yk  
{ '5|h)Q5  
sSiteURL= sURL; |]X  
sFilePath = sPath; k<\$Oo
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sFileName = sName; &E=>Hj(dTG  
this.nSplitter = nSpiltter; UaB @  
8{X"h#  
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} ikSt"}/hd  
-xA2pYz"  
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public String getSSiteURL() Rw:*'1  
{ HEM9E&rL  
return sSiteURL; ssN6M./6  
} ktpaU,%  
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public void setSSiteURL(String value) pj?f?.^  
{ 7w6cwHrL@  
sSiteURL = value; L>RP-x>  
} Ls] g  
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public String getSFilePath() n4#;k=mA  
{ n$ou- Q  
return sFilePath; 4s*ZS}] o  
} "*srx]  
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public void setSFilePath(String value) ry`z(f  
{ #ka
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sFilePath = value; ?}U(3  
} B2'i7Ps  
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m1Mt#@,$  
public String getSFileName() vbC\?\_  
{ U_n9]Z  
return sFileName; 3GhRWB-U  
} ne_TIwfw-  
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public void setSFileName(String value) f>UXD
 
{ H
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sFileName = value; g9Xu@N;bL  
} Pu*6"}#~  
2;DuHO1  
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public int getNSplitter() uYs5f.! `  
{ YH\O
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return nSplitter; )W;o<:x3  
} {^7Hgg  
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public void setNSplitter(int nCount) AK*LyR?  
{ 3@M|m<_R$  
nSplitter = nCount; CkoLTY  
} 06c>$1-?  
} 10q'Z}34  
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p8h9Ng*&`  
/* -y8`yHb_  
**Utility.java ;7E7!t^  
*/ `Nb[G)Xh  
package NetFox; LE9(fe) fe  
:7!0OVQla\  
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public class Utility { N343qU  
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public Utility() iS WU'K  
{ =/y]d<g  
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} !'&n-Q  
4W#vP
  
//线程睡眠 Q@<S[Qh[.  
public static void sleep(int nSecond) Vzdh8)Mu\  
{ vd 0ljA  
try{ c#Sa]n  
Thread.sleep(nSecond); PT=2@kH  
} XWS%zL
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catch(Exception e) :(!`/#6H  
{ 3=FZ9>by  
e.printStackTrace (); Li/O  
} aJ-K?xQ  
} EN;}$jZ>47  
s:#V(<J  
//日志 sk,ox~0R  
public static void log(String sMsg) ^S UPi  
{ 4'`{H@]tb  
System.err.println(sMsg);
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} U(Nu%  
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public static void log(int sMsg) Tx|Ir+f6L  
{ E.7  
System.err.println(sMsg); e;Ti&o}  
} !`g~F\l  
} -@yh>8v  
[ sN EHf  
(@<lRA ^  
/* 4)h]MOZ  
**TestMethod.java )Dw,q~xgg0  
*/ 8\^}~s$$A
 
package NetFox; p^%YBY#,H  
 FT#8L  
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public class TestMethod { s+,OxRVw(  
Zhh2v>QOy  
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public TestMethod() M=FxB;v  
{ ///xx/weblogic60b2_win.exe z3&]%Q&  
try{ ewa wL"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -(bXSBs#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (l-tvk4Ln  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M)'HCnvs'  
fileFetch.start(); )6,de2Pb  
} yj;sSRT  
catch(Exception e){e.printStackTrace ();} y.#")IAF  
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} cC=[Saatsf  
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public static void main(String[] args) hU`wVy  
{ 96 q_K84K  
new TestMethod(); 0E,8R{e  
} 0fF(Z0R,  
} +Z7th7W/,  
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