http断点续传简单实现（java)

/* fk x \=  
**SiteFileFetch.java ^cz(}N 6&  
*/ t>$kWd{9e;  
package NetFox; [a wjio  
import java.io.*; fu]s/'8B  
import java.net.*; LMAE)]N  
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public class SiteFileFetch extends Thread { EG=Sl~~o  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {>)#H
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long[] nStartPos; //开始位置 _<OSqE  
long[] nEndPos; //结束位置 p$3sME$L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 lH6OcD:kj  
long nFileLength; //文件长度 F 70R1OYU  
boolean bFirst = true; //是否第一次取文件 L>RP-x>  
boolean bStop = false; //停止标志 u2?|Ue@[  
File tmpFile; //文件下载的临时信息 `I,,C,{C  
DataOutputStream output; //输出到文件的输出流 < RH UH)I  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） vz7J-CH  
public SiteFileFetch(SiteInfoBean bean) throws IOException W|g4z7Pb  
{ 4k@5/5zsM  
siteInfoBean = bean; >)M`IU[d^.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n74V|b6W  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lUvpszH=  
if(tmpFile.exists ()) )j0TeE1R  
{ In<n&ib  
bFirst = false; m~-K[+ya`D  
read_nPos(); m1Mt#@,$  
} 1R1z  
else u*ObwcI/Bn  
{ Gf
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nStartPos = new long[bean.getNSplitter()]; ei[j1F  
nEndPos = new long[bean.getNSplitter()]; `u teg=  
} X6@WwM~qz  
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} :i.{  
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public void run() E4~<V=2l  
{ H
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//获得文件长度 ?-dX`n  
//分割文件 vPTM  
//实例FileSplitterFetch Ne[7gxpu  
//启动FileSplitterFetch线程 ASk|A!  
//等待子线程返回 ZOeQ+j)|I  
try{ 4hTMbS_;  
if(bFirst) pH"#8O&  
{ HoRg^Ai?\  
nFileLength = getFileSize(); ,>0*@2
 
if(nFileLength == -1) eQp4|rf  
{ KmA;HiH%J  
System.err.println("File Length is not known!"); $+Z)  
} "2)H'<  
else if(nFileLength == -2) ,P70J
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{ jw^<IMAG\8  
System.err.println("File is not access!"); hp5|@  
} 2Q/4bJpd  
else mUdOX7$c>  
{ 0"\H^
  
for(int i=0;i<nStartPos.length;i++) @M_oH:GV  
{ hPUYyjXPB  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "NXB$
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} IDB+%xl#S  
for(int i=0;i<nEndPos.length-1;i++) 2ZG5<"DQ"  
{ [f1 (`<  
nEndPos = nStartPos[i+1]; _lGdUt 2  
} |yQZt/*SOZ  
nEndPos[nEndPos.length-1] = nFileLength; C1m]*}U  
} I+[>I=ewa  
} Kgi<UkFP  
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//启动子线程 ZaV8qAsP  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ['B?i1 .  
for(int i=0;i<nStartPos.length;i++) &:dH,  
{ Q;43[1&3w  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gy 3i+J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  a1t4Dd  
nStartPos,nEndPos,i); P3)Nl^/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L
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fileSplitterFetch.start(); / zB0J?  
} =/y]d<g  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a1+#3X.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X[PZg{   
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2[RoxKm  
nEndPos = " + nFileLength); %.^_Ps0  
// fileSplitterFetch[nPos.length-1].start(); T_@K&<  
@` 1Ds  
d%RC  
//等待子线程结束 | r&k48@  
//int count = 0; T`\x
,` ^  
//是否结束while循环 t>urc  
boolean breakWhile = false; :U3kW8;UMP  
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while(!bStop) beRVD>T  
{ r&R B9S@*h  
write_nPos(); El[)?+;D  
Utility.sleep(500); +;N2p1ZBf  
breakWhile = true; %)|9E>fP]N  
}L+L"l&  
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for(int i=0;i<nStartPos.length;i++) bm?sbE  
{ g
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if(!fileSplitterFetch.bDownOver) 7hlO#PYZ  
{ v9w'!C)b  
breakWhile = false; i|w81p^o  
break; (e!0]Io@  
} }Qip&IN  
} F+,~v-  
if(breakWhile) }z _  
break; "$ Y_UJT7  
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//count++; w)kNkD  
//if(count>4) dZ  rAn  
// siteStop(); aqRhh=iS  
} ypKUkH/  
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System.err.println("文件下载结束！"); `\T]ej}zvI  
} \>:CvTzF  
catch(Exception e){e.printStackTrace ();} x(etb<!jd  
} #{?PbBE}  
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//获得文件长度 FbaEB RM  
public long getFileSize() 7n8~K3~;  
{ _=Z,E.EN  
int nFileLength = -1; Xjo5v*Pu  
try{ /'].lp  
URL url = new URL(siteInfoBean.getSSiteURL()); ^)(bM$(`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~P8tUhff
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httpConnection.setRequestProperty("User-Agent","NetFox"); T>}5:,N~  
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int responseCode=httpConnection.getResponseCode(); @kpv{`Y  
if(responseCode>=400) 2XFU1 AW  
{ <j*;.yyC  
processErrorCode(responseCode); iOR_[y,  
return -2; //-2 represent access is error F(k.,0Nc  
} !MYSfPdS  
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String sHeader; v, n$^R  
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for(int i=1;;i++) lE;Ewg  
{ #!aN{nK0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {1V($aBl  
//Utility.log(in.readLine()); D7lK30  
sHeader=httpConnection.getHeaderFieldKey(i); 4]G?G]lS>  
if(sHeader!=null) @&%'4j&+  
{ '(f&P=[b  
if(sHeader.equals("Content-Length")) <3xyjX'NE  
{ x_|UPF  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4}_j`d/8|  
break; uw[<5  
} *5vV6][  
} M=1nQF2J  
else 4 Y;Nm1@  
break; Mn9dqq~a
 
} "uuVy$6C  
} so"$m  
catch(IOException e){e.printStackTrace ();} Izhee%c  
catch(Exception e){e.printStackTrace ();} ,sA[)wP{  
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Utility.log(nFileLength); r"``QmM  
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return nFileLength; 8P^ITL z%  
} Rv#]I#O  
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/2UH=Q!x4E  
//保存下载信息（文件指针位置） :*i
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private void write_nPos() 0y 7"SiFY  
{ -BRc8 /  
try{ bSfpbo4(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]l1\? I  
output.writeInt(nStartPos.length); a:"Uh**  
for(int i=0;i<nStartPos.length;i++) ^* J2'X38I  
{ UUzYbuS>&l  
// output.writeLong(nPos); =NnNN'}  
output.writeLong(fileSplitterFetch.nStartPos); m@"QDMHk.  
output.writeLong(fileSplitterFetch.nEndPos); #JgH}|&a$  
} W%T>SpFl  
output.close(); 73V|6tmgY  
} q}~3C1  
catch(IOException e){e.printStackTrace ();} ?&|5=>u2}$  
catch(Exception e){e.printStackTrace ();} *+j*{>E  
} @x"0_Qw  
::ajlRZG  
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//读取保存的下载信息（文件指针位置） plb!.g  
private void read_nPos() rM .|1(u  
{ u=/{cOJI6  
try{ Y
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~aMlr6;  
int nCount = input.readInt(); v%"|WV[N  
nStartPos = new long[nCount]; S{;sUGcu  
nEndPos = new long[nCount]; Pl=ZRKn  
for(int i=0;i<nStartPos.length;i++) R%Q@  
{ b~'"^ Bts*  
nStartPos = input.readLong(); V,q](bg  
nEndPos = input.readLong(); Pa{%\dsv  
} BF
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input.close(); uT}' Y)m  
} 5]n[]FW  
catch(IOException e){e.printStackTrace ();} S`#w+C#EW  
catch(Exception e){e.printStackTrace ();} -j73Wz  
} G]+&!4  
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private void processErrorCode(int nErrorCode) k\WR ]  
{ 1#.>a$>  
System.err.println("Error Code : " + nErrorCode); Z @^9PQG$  
} J3n-`k8  
]}U*_rM:  
H*[M\gN$  
//停止文件下载 X:6c}p%,!  
public void siteStop() &?q/1vLa  
{ *MJX?  
bStop = true; _59huC.  
for(int i=0;i<nStartPos.length;i++) g=QDu7Ux  
fileSplitterFetch.splitterStop(); VY~yg*  
+6';1Nb@  
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} (vb SM}P  
} }oL'8-y  
//负责部分文件的抓取  ~ ip,Nl  
**FileSplitterFetch.java QV{}K  
*/ $lLz3YS  
package NetFox; 'R c,Mq'  
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import java.io.*; *Eo?k<:zPm  
import java.net.*; Pb?$t  
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public class FileSplitterFetch extends Thread { "br,/Dk>MX  
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String sURL; //File URL ]`kmjn  
long nStartPos; //File Snippet Start Position !Cr(Pe]  
long nEndPos; //File Snippet End Position $4/yZaVb  
int nThreadID; //Thread's ID MhR:c7,  
boolean bDownOver = false; //Downing is over *.!Np9l,V  
boolean bStop = false; //Stop identical .Yf:[`Q6g  
FileAccessI fileAccessI = null; //File Access interface VxV
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 #`o2Z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4"(<X  
{ S"xKL{5  
this.sURL = sURL; R:#k%}W  
this.nStartPos = nStart; +R|z{M)*  
this.nEndPos = nEnd; ; mZW{j  
nThreadID = id; !4^C #{$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m^bNuo  
} VzY8rI  
8P1=[i]  
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public void run() `[W[H(AjQ  
{ P*I}yPeb  
while(nStartPos < nEndPos && !bStop) EL(nDv  
{ 1IZ3=6  
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try{ f}x.jxY?  
URL url = new URL(sURL); H^s<{E0<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n p\TlUc  
httpConnection.setRequestProperty("User-Agent","NetFox"); paKSr|O  
String sProperty = "bytes="+nStartPos+"-"; k} |   
httpConnection.setRequestProperty("RANGE",sProperty); #MRMNL@   
Utility.log(sProperty); )pq;*~IBI  
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InputStream input = httpConnection.getInputStream(); Of4^?` ^  
//logResponseHead(httpConnection); "x
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byte[] b = new byte[1024]; p$PKa.Y3  
int nRead; X)7x<?DAy  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0l-Ef1  
{ {\c(ls{  
nStartPos += fileAccessI.write(b,0,nRead); J2'Nd'  
//if(nThreadID == 1) WJ4li@T7V  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /f|X(docI  
} [3{W^WSOz  
a{ ?`t|  
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Utility.log("Thread " + nThreadID + " is over!"); &N
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bDownOver = true; 1 D<_
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//nPos = fileAccessI.write (b,0,nRead); J"=vE=  
} ^yyC [Mz  
catch(Exception e){e.printStackTrace ();} wtH? [>S;)  
} (2:/8\_P  
} f;1K5Y  
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=8; {\  
//打印回应的头信息 aC%m-m  
public void logResponseHead(HttpURLConnection con) uF1~FKB  
{ @U3Vc|  
for(int i=1;;i++) )u/yF*:n  
{ 6^%68N1k  
String header=con.getHeaderFieldKey(i); dIRm q+d^  
if(header!=null) Qj.l:9%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4KH45|;3  
Utility.log(header+" : "+con.getHeaderField(header)); ~%SH3$  
else C4~;yhz  
break; &?*V0luP)  
} XgLL!5`  
} gG-BVl"59  
1@QZnF5[  
/+\uqF8F  
public void splitterStop() dt`{!lts'  
{ ,!7 H]4Qx  
bStop = true; ,'p2v)p^4  
} \H=&`?  
!+L/Khw/C  
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} rld67'KcE  
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/* 1DvR[Lx%  
**FileAccess.java -lhLA`6_R  
*//文件访问(定位，写) lJE93rXU  
package NetFox; &8]d
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import java.io.*; V{^!BBQ  
7tcPwCc{  
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public class FileAccessI implements Serializable{ TW[_Ko86  
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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 5lm<%  
RandomAccessFile oSavedFile; UmQ?rS8d  
long nPos; 6bBB/yd  
t=-SH^$SR  
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public FileAccessI() throws IOException ^sVX)%  
{ 76Vl6cPu>  
this("",0); *X, /7C   
} @ ]/AjjLt  
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public FileAccessI(String sName,long nPos) throws IOException }w1~K'ck}>  
{ QoG cWJ  
oSavedFile = new RandomAccessFile(sName,"rw"); 1;mW,l'`  
this.nPos = nPos; *7h!w!LN~  
oSavedFile.seek(nPos); 4*'pl.rb>  
} IaT$6\>  
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public synchronized int write(byte[] b,int nStart,int nLen) XwlbJ=mf  
{ aEWWFN  
int n = -1; 4(1
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try{ ;~\MZYs3m  
oSavedFile.write(b,nStart,nLen); [&nh5|f  
n = nLen; 9Iz%ht  
} hb^7oq"a  
catch(IOException e) t| 'N+-T3  
{ `$B3X  
e.printStackTrace (); :@!ic
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} l?Fb ='#  
@)-$kk*  
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return n; 5<ux6,E1{  
} j'BMAn ?  
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7 <Q5;J&;  
} )I$q5%q8  
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/* ,I_^IitN  
**SiteInfoBean.java &b
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*/ e`v`XSA[p  
package NetFox; @$2))g`  
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public class SiteInfoBean { |7}CQU  
a'jR#MQl?  
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private String sSiteURL; //Site's URL aBw2f[mo  
private String sFilePath; //Saved File's Path * C6a?]  
private String sFileName; //Saved File's Name i![dPM  
private int nSplitter; //Count of Splited Downloading File (>I`{9x>6  
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pTyi!:g3W  
public SiteInfoBean() 3Bx:Ntx<  
{//nSplitter的缺省值为5 !ZI7&r`u;  
//default value of nSplitter is 5 ZJ 77[  
this("","","",5); *L'>U
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} jD`d#R  
*r$+&8V\n  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) GR"Eas.$  
{ Sf,R^9#|  
sSiteURL= sURL; Eyh51IB.  
sFilePath = sPath; S.d^T](  
sFileName = sName; ?w+Ix~k  
this.nSplitter = nSpiltter; Zt&6Ua[Y}  
@bnG:np  
K&U7H:  
} `/MvQ/  
=l0Jb#d  
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public String getSSiteURL() ~~6^Sh60g  
{ DmBS0NyR7Y  
return sSiteURL; ZKOXI%~Mc  
} {vN}<f`  
YNBHBK4;  
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public void setSSiteURL(String value) fuB)qt!E  
{ CCX8>09  
sSiteURL = value; V86Xg:?7  
} ocyb5j  
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public String getSFilePath() =07]z@s  
{ 4L73]3&  
return sFilePath; bug Ot7  
} gt7VxZ  
]Bm>-*@0N  
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public void setSFilePath(String value) fVM`-8ZTq  
{ @5[kcU>  
sFilePath = value; ]Y| 9?9d  
} s#S%#LM  
vc]cNz:mQ  
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public String getSFileName() 1 `7<2w  
{ E3*\ ^Q_  
return sFileName; ,~);EC=`  
} XJ0oS32_wK  
CY& hIh~S@  
]D!k&j~P  
public void setSFileName(String value) "9bN+1[<  
{ 9P<[7u  
sFileName = value; _"%B7FK  
} 3J=Y9 }  
dna6QV>A  
Bs MuQ|!  
public int getNSplitter() NcAp_q? 4  
{ k3t78Qg  
return nSplitter; D>!6,m2  
} eJo3 MK  
/LM4-S  
rO:
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public void setNSplitter(int nCount) cf7v[ZZ}  
{ w?,M}=vg  
nSplitter = nCount; Y=T'WNaL)0  
} ZK'-U,Y.H7  
} '/I:^9  
\)48904^  
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/* x#N-&baS  
**Utility.java `:eViVl6e  
*/ ,JEbd1Uf  
package NetFox; >z`,ch6~  
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public class Utility { cM_Fp  
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public Utility() pfd#N[c  
{ }N*>QR5K  
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} PjIeZ&p  
=D^TK-H  
//线程睡眠 oy<
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public static void sleep(int nSecond) 2 /y}a#s  
{ oR*=|B  
try{ K$ v"Uk  
Thread.sleep(nSecond); vLO&Lpv  
} /"ymZI!k\  
catch(Exception e) F#{gf
h  
{ (Bo bB]~a  
e.printStackTrace (); ;p ]y)3  
} w&BGJYI  
} E&B{5/rv  
to6;?uC+|i  
//日志 z\/53Sy<  
public static void log(String sMsg) 6TH!vuQ1(  
{ .]|Zf!>}s  
System.err.println(sMsg); QI_59f>  
} ]/T-t1D  
GPWr>B.{:S  
wG8Wez%  
public static void log(int sMsg) @S 6u9v  
{ D^Ys)- d  
System.err.println(sMsg); 0 3~Ikll  
} r Db>&s3  
} o/
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> 4oY3wk8  
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/* {?{U,&  
**TestMethod.java -n*;W9  
*/ c0 WFlj9b  
package NetFox; @1R8-aa-r  
w.N,)]h  
}xlKonk  
public class TestMethod { T[Pa/j{  
s{/qS3=  
:o"8MZp  
public TestMethod() dZGbC9  
{ ///xx/weblogic60b2_win.exe MF[z-7  
try{ jK8'T_Pah  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P.sg
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?
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SiteFileFetch fileFetch = new SiteFileFetch(bean); !6w{(Rc(C  
fileFetch.start(); Gowp <9 F  
} a-n4:QT  
catch(Exception e){e.printStackTrace ();} iS@\ =CK  
|)W!jC&k  
Ak~4|w-  
} Oe1 t\  
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"D*
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public static void main(String[] args) 83.E0@$  
{ w5]l1}rl  
new TestMethod(); :k46S<RE  
} %d: A`7x  
} A2x;fgi  
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