http断点续传简单实现（java)

/* 2XI%4  
**SiteFileFetch.java X`aED\#\h  
*/ .7kVC  
package NetFox; #); 6+v  
import java.io.*; ZDVaKDqZ_  
import java.net.*; .4^Paxz  
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public class SiteFileFetch extends Thread { BryMq !  
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SiteInfoBean siteInfoBean = null; //文件信息Bean G
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long[] nStartPos; //开始位置 "^trHh8=  
long[] nEndPos; //结束位置 1gt[_P2u  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 d@w I: 7  
long nFileLength; //文件长度 Yb6\+}th  
boolean bFirst = true; //是否第一次取文件 qkBnEPWZy  
boolean bStop = false; //停止标志 qb9%Y/xy  
File tmpFile; //文件下载的临时信息 WYh7Y  
DataOutputStream output; //输出到文件的输出流 5o72X k  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） s
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public SiteFileFetch(SiteInfoBean bean) throws IOException |BW956fBU  
{ }YSH8d  
siteInfoBean = bean; -[7.VP   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); nut7b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Kp&d9e{ Yc  
if(tmpFile.exists ()) ?_^9e  
{ X
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bFirst = false; 5$#<z1M.&  
read_nPos(); ZHF@k'vm/9  
} T }8aj  
else .K93VTzy  
{ xp&I~YPH  
nStartPos = new long[bean.getNSplitter()]; 9rid98~d  
nEndPos = new long[bean.getNSplitter()]; q O
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} m0#hG x  
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} z^b\hR   
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public void run() 6S&#8l  
{  o _CVZ  
//获得文件长度 }.hBmhnZmI  
//分割文件 @%TQ/L^|  
//实例FileSplitterFetch ECSC,oJ  
//启动FileSplitterFetch线程 K:Ap|F  
//等待子线程返回 S2NsqHJr  
try{ bHMlh^{`%  
if(bFirst) fSP~~YSeU  
{ iKK=A.g  
nFileLength = getFileSize(); 3a5H<3w_  
if(nFileLength == -1) givK{Yt<B  
{ 4-"wFp  
System.err.println("File Length is not known!"); Mfz5:'  
} F?dTCa  
else if(nFileLength == -2) 980+Y  
{ ^*r${Nj  
System.err.println("File is not access!"); Oh^X^*I$@  
} 8%NX)hZyq}  
else q"cFw${  
{ ^g0 Ig2'  
for(int i=0;i<nStartPos.length;i++) E`
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{ pQ/:*cd+M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L fi]s  
} }
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for(int i=0;i<nEndPos.length-1;i++) PY2`RZ/@  
{ 9w(j2i q  
nEndPos = nStartPos[i+1]; K1hw'AaQ  
} OYzJE@r^  
nEndPos[nEndPos.length-1] = nFileLength; _+. t7q^  
} u,pm\  
} {NFeX'5bP  
y, Z
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//启动子线程 a} /Vu"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jn7}jWA  
for(int i=0;i<nStartPos.length;i++) gPfaiVY  
{ :Hd<S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m<yA] ';s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J8%|Gd0#4  
nStartPos,nEndPos,i); IQ_0[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cjh&$aq  
fileSplitterFetch.start(); P]TT  
} 01dx}L@hz  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), EvYw$
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <Kh\i'8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ZJ4"QsF  
nEndPos = " + nFileLength); Y[H_?f=;%  
// fileSplitterFetch[nPos.length-1].start(); .xx#>Y-\  
Cam}:'a/`  
%pt$S~j  
//等待子线程结束 4/jY;YN,2  
//int count = 0; }}2kA  
//是否结束while循环 pFK |4
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boolean breakWhile = false; (kHR$8GFM  
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while(!bStop) J.&q[  
{ sH]AB=_  
write_nPos(); *HC8kD a%$  
Utility.sleep(500); e%P;Jj476  
breakWhile = true; {, |"Rpd  
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for(int i=0;i<nStartPos.length;i++) 8N`$7^^  
{ *"5a5.`%,  
if(!fileSplitterFetch.bDownOver) =?lT&|"  
{ <_>6a7ra  
breakWhile = false; /;0>*
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break; d{he  
} =oTYwU  
} SQ!lgm1bA  
if(breakWhile) ]UI+6}r  
break; t[maUy_A  
CvW((<?  
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//count++;  LJ))  
//if(count>4) e.+)0)A-  
// siteStop(); '2tEKVb  
} cg.e(@(  
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System.err.println("文件下载结束！"); ;!}SgzSH}  
} v;Dcq  
catch(Exception e){e.printStackTrace ();} U
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} NQJqS?^W&M  
p^:Lj9Qax  
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//获得文件长度 J*Hn/m  
public long getFileSize() EVL;"   
{ /$z@_U[L  
int nFileLength = -1; v(h Xk]S  
try{ C]H <L#)ZU  
URL url = new URL(siteInfoBean.getSSiteURL()); v6VhXV6$|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); of`]LU:  
httpConnection.setRequestProperty("User-Agent","NetFox"); "6dbRo5%  
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int responseCode=httpConnection.getResponseCode(); O}-7 V5  
if(responseCode>=400) {|h"/  
{ Qzhnob#C9  
processErrorCode(responseCode); O)|4>J*B  
return -2; //-2 represent access is error Ltw7b  
} \.a .'l  
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EM*OrUe  
String sHeader; hyKg=Foq  
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Q7
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for(int i=1;;i++) ?<?C*W_  
{ KUutC
:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); eW)I}z+{  
//Utility.log(in.readLine()); W~F/ZrT3A  
sHeader=httpConnection.getHeaderFieldKey(i); a~7osRmp0  
if(sHeader!=null) ;8T=uCi  
{ ~BZV:Es  
if(sHeader.equals("Content-Length")) KaE;4gwM  
{ bW^QH-t  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); HdUW(FZ  
break; KL mB  
} -C}59G8  
} grdyiBSVn  
else _ICDtG^  
break; b=UMoWS  
} 4.B*B3  
} j2 ^T:q[  
catch(IOException e){e.printStackTrace ();} l&Ghs@>Kl  
catch(Exception e){e.printStackTrace ();} dO;vcgvb  
xg^^@o  
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Utility.log(nFileLength); X9A[  
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return nFileLength; #ljg2:I+  
} pf@}4PN}  
*.c9$`s  
(I ds<n"  
//保存下载信息（文件指针位置） 50aWFJYw  
private void write_nPos() &jZ|@K?  
{ Q3%# o+R>  
try{ h;p%EZ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i;zGw.;Q  
output.writeInt(nStartPos.length); 9*+0j2uhQ  
for(int i=0;i<nStartPos.length;i++) llfiNEK5;  
{ RhNaYO  
// output.writeLong(nPos); +4g%?5'  
output.writeLong(fileSplitterFetch.nStartPos); @nX2*j*u  
output.writeLong(fileSplitterFetch.nEndPos); d.j'0w"   
} Pd "mb~  
output.close(); d"6]?  
} tW:/R@@  
catch(IOException e){e.printStackTrace ();} N8YBu/  
catch(Exception e){e.printStackTrace ();} ;u};&sm  
} E9B*K2l^{  
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//读取保存的下载信息（文件指针位置） (g/
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private void read_nPos() AJ
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{ AV 5\W}  
try{ O;e8ft '|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); AOx3QgC^NO  
int nCount = input.readInt(); fk7Cf"[w  
nStartPos = new long[nCount]; B/D\gjb  
nEndPos = new long[nCount]; ,V]A63J  
for(int i=0;i<nStartPos.length;i++) n~ >h4=h  
{ +F~0\#d  
nStartPos = input.readLong(); iQzX-a|4]  
nEndPos = input.readLong(); T[XP\!z]B!  
} \*%i#]wO@  
input.close(); 9X$#x90  
} uWB:"&!^  
catch(IOException e){e.printStackTrace ();} 27],O@2?L  
catch(Exception e){e.printStackTrace ();} /1W7<']>xV  
} n*i'vtQ8  
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private void processErrorCode(int nErrorCode) dXcPWbrU4  
{ b;J0'o^G|  
System.err.println("Error Code : " + nErrorCode); .)@tXH=}+  
} n*m"L|:ff  
}K/}(zuy1Y  
i$JG^6,O  
//停止文件下载 a][pTC\rb  
public void siteStop() .5!sOOs$P  
{ %-ZR~*  
bStop = true; mbX)'. +L  
for(int i=0;i<nStartPos.length;i++) Z&]+A,  
fileSplitterFetch.splitterStop(); s1Tl.p5  
,|.*,  
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} FQ^<,  
} 8PoH
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//负责部分文件的抓取 'lN*Ys iDi  
**FileSplitterFetch.java ZcTL#OTP  
*/ MLt'YW^  
package NetFox; U+*oI*  
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import java.io.*; (9KDtr*(2i  
import java.net.*; =(.mf  
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5fegWCJ  
public class FileSplitterFetch extends Thread { DN"S,  
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String sURL; //File URL Gf H*,1x  
long nStartPos; //File Snippet Start Position ii_|)udz  
long nEndPos; //File Snippet End Position :m*!?QGdL  
int nThreadID; //Thread's ID QtnM(m  
boolean bDownOver = false; //Downing is over Db#W/8 a8k  
boolean bStop = false; //Stop identical fVH*dX'Jz  
FileAccessI fileAccessI = null; //File Access interface }$Hs;4|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x
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{ h0F0d^W.  
this.sURL = sURL; P /c Q1  
this.nStartPos = nStart; GJC!0{8;  
this.nEndPos = nEnd; *(d6Z#  
nThreadID = id; 8O8\q ;US  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d2C[wQF  
} }fJ:wku  
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public void run() 8! H8[J  
{ @],6SKbG6  
while(nStartPos < nEndPos && !bStop) X,WQ'|rC  
{ <JL\?)}n  
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try{ C#U<k0R  
URL url = new URL(sURL); z^gQ
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nDHHYp
 
httpConnection.setRequestProperty("User-Agent","NetFox"); H.YIv50E  
String sProperty = "bytes="+nStartPos+"-"; 4|> rwQ~t  
httpConnection.setRequestProperty("RANGE",sProperty); #Mj$o;SX  
Utility.log(sProperty); ,7^d9v3t  
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InputStream input = httpConnection.getInputStream(); S'Z70 zJ  
//logResponseHead(httpConnection); dGbU{#"3s  
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byte[] b = new byte[1024]; KInUe(g<9M  
int nRead; ^&+zA,aL,A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) g08*}0-k  
{ qri}=du&F  
nStartPos += fileAccessI.write(b,0,nRead); eJU;*] xfH  
//if(nThreadID == 1) .'t (-eT,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2BoFyL*  
} bz,Da  
2{A;du%&  
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Utility.log("Thread " + nThreadID + " is over!"); LP^p~5Az  
bDownOver = true; VHXI@UT*  
//nPos = fileAccessI.write (b,0,nRead); "gXxRHTX  
} #4P8
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catch(Exception e){e.printStackTrace ();} >I$B=  
} dT5J-70Fl  
} &`9j)3^J.  
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z.
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//打印回应的头信息 ]b4pI*:$I  
public void logResponseHead(HttpURLConnection con) Ik`O.Q.}  
{ F(Lb8\to\M  
for(int i=1;;i++) 5;IT64&]  
{ _PK}rr?"7O  
String header=con.getHeaderFieldKey(i); k$ZRZ{ E+  
if(header!=null) )Rjb/3*!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @v>l[6]>^  
Utility.log(header+" : "+con.getHeaderField(header)); Mw/?wtW  
else vuYO\u+ud  
break; }1QI"M*  
} fNmE,~
 
} @SU8\:(U  
X AQGG>  
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public void splitterStop() =WIE>*3[  
{ 4bP13f  
bStop = true; 2]L=s3  
} (C,e6r Y  
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} `TUZZz  
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/* hHcJN
 
**FileAccess.java P+[QI U  
*//文件访问(定位，写) T!MZ+Ph`F  
package NetFox; d; 9*l!CF  
import java.io.*; iJFr4o/R  
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ov8 ByJc  
public class FileAccessI implements Serializable{  }VF#\q  
3pB}2]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8EOh0gk7  
RandomAccessFile oSavedFile; GxxDY]!  
long nPos; ~|h lE z  
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public FileAccessI() throws IOException d:A}CBTSY  
{ WrNLGkt  
this("",0); NwguP  
} KacR?Al  
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public FileAccessI(String sName,long nPos) throws IOException <3b'm*  
{ k^z0Lo|)'  
oSavedFile = new RandomAccessFile(sName,"rw"); =4eUAeH {w  
this.nPos = nPos; #,G1R7  
oSavedFile.seek(nPos); 1Q]Rd  
} |+98h&U~  
cgyp5\*>+  
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public synchronized int write(byte[] b,int nStart,int nLen) |pJC:woq  
{ g+/0DO_F3  
int n = -1; j.DHqHx  
try{ T.kyV|  
oSavedFile.write(b,nStart,nLen); kBo;h.[l  
n = nLen; -LTKpN`[@  
} wzd`l?o,  
catch(IOException e) ndw7v  
{ ;+sl7qlA4  
e.printStackTrace (); xOythvO  
} @dl8(ILk'  
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o]<jZ_|gB  
return n; %,/lqcFo  
} N>0LQ MI  
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%<ic%gt`#  
} v9=}S\=Cd  
s.VA!@F5  
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/*
} ~| k  
**SiteInfoBean.java ^-hErsK  
*/ @D~B{Hg  
package NetFox; 1]T|6N?  
+c--&tBo  
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public class SiteInfoBean { gw^'{b  
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private String sSiteURL; //Site's URL ?Nf 5w  
private String sFilePath; //Saved File's Path  Hy]  
private String sFileName; //Saved File's Name zzJja/mp  
private int nSplitter; //Count of Splited Downloading File vg)Z]F=t(  
:=*}htP4C  
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public SiteInfoBean() [[WF0q  
{//nSplitter的缺省值为5 !;v.>.lw  
//default value of nSplitter is 5 Mu{BUtkzG  
this("","","",5); ~EEs}i  
} 9#qeFBI  
"k:=Y7Dx  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]3ifdGk  
{ *nRNg
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sSiteURL= sURL; s5&=Bsv  
sFilePath = sPath; (Sv>NQp  
sFileName = sName; v*z(@<Y  
this.nSplitter = nSpiltter; {:bN/zV#  
0}]SUe^  
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} gzf-)J  
e"k/d<  
OX\$nQ\o  
public String getSSiteURL() W\8Ln>  
{ Z(e^iH  
return sSiteURL; ?qmp_2:WU  
} _'!kuE,*1  
GS;%zdH~  
e)@3m.  
public void setSSiteURL(String value) j+kC-U;  
{ 8md*wEjk  
sSiteURL = value; &^!h}D%T/  
} 8AL\ST51x"  
6ZOy&fd,Ty  
1$pb (OK  
public String getSFilePath() XN;&qR^j  
{ gl8Ib<{  
return sFilePath; Q`ME@vz  
} S_b/DO  
X
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public void setSFilePath(String value) !l 6dg&
 
{ N|K4{Frm  
sFilePath = value; uwmQ?LS]V  
} TTZe$>f  
~aTKG|74  
<jA105U"m>  
public String getSFileName() p?# pT}1  
{ nlc.u}#  
return sFileName; -tLO.JK<  
} c5% 6Y2W0  
e,gyQjJR  
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public void setSFileName(String value) .c+9P<VmC}  
{ 5l{Ts04k%  
sFileName = value; :Ht;0|[H  
} 28I^$> [  
KpHw-6"  
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public int getNSplitter() cn`iX(ZgR  
{ 
!%)]56(  
return nSplitter; 2g-` ]Vqb  
} ny*i+4Mb  
O.QK"pKD\  
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public void setNSplitter(int nCount) ezm&]F`  
{ n3KI+I%nQ  
nSplitter = nCount; ZZxk]D<  
} :"1|AJo)  
} ]a'99^?\  
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h6:#!Rg  
/* [?0d~Q(R#  
**Utility.java cU.9}-)  
*/ pUYM}&dX  
package NetFox; (?0`d  
bHE2,;o  
<vV_%uoM  
public class Utility { aYn^)6^  
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public Utility() GVGlVAo|@  
{ V3Z]DA  
g}LAks  
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} i3$$,W!  
C[sh,  
//线程睡眠 6gL-OJNo  
public static void sleep(int nSecond) T{v>-xBRy  
{ w_tJ7pz8T  
try{ }<a^</s  
Thread.sleep(nSecond); >l']H*&B<  
} p'_%aVm7  
catch(Exception e) /]
^#b  
{ GL$De,V  
e.printStackTrace (); X{xBYZv4  
} #%0Bx3uM  
} W~1~k{A  
avQJPB)}Sb  
//日志 ^x>Qf(b  
public static void log(String sMsg) RE2&mYt  
{ 6w8">~)Z  
System.err.println(sMsg); Yr.sm!xA  
} ^TY;Zp  
"Jq8?FoT  
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public static void log(int sMsg) K<`osdp=&  
{ `F YjQe"p  
System.err.println(sMsg); =@&cHY  
} s$ENFp7P  
} EOj"V'!  
b?X.U}62_  
l e4?jQQ@L  
/* +ZMls [  
**TestMethod.java @mP]*$00  
*/ RGKYW>$0RR  
package NetFox; )Z 9E=%  
8Me:Yp_Xt  
PXzsj
.  
public class TestMethod { *a;@*  
% 2$/JZ  
>{gPN"S"a  
public TestMethod() S8[=S  
{ ///xx/weblogic60b2_win.exe Dl(3wgA  
try{ K_)eWf0a  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i':ydDOOHA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fWfk[(M'9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); IJYL s  
fileFetch.start(); J]lrS  
} (.wIe/  
catch(Exception e){e.printStackTrace ();} wI]"U2L5  
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^z1&8k"[^  
} kft#R#m  
 McH>"`  
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public static void main(String[] args) L37Y+C//  
{ 0R{dNyh{  
new TestMethod(); ('wY9kvL&  
} &qpr*17T  
} 1tTgP+  
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