http断点续传简单实现（java)

/* #gh p/YoTq  
**SiteFileFetch.java /7bw: h;  
*/ $ye^uu;Z  
package NetFox; ||uZ bP@  
import java.io.*; ;}LJh8_  
import java.net.*; Oqpp=7  
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public class SiteFileFetch extends Thread { '/k^C9~m r  
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SiteInfoBean siteInfoBean = null; //文件信息Bean +p3 Z#KoC  
long[] nStartPos; //开始位置 |K%}}g[<e;  
long[] nEndPos; //结束位置 sf`PV}a1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a\=-D:  
long nFileLength; //文件长度 =f>HiF  
boolean bFirst = true; //是否第一次取文件  }mKwFVZ  
boolean bStop = false; //停止标志 (Akd8}nf~  
File tmpFile; //文件下载的临时信息 t\8&*(&3F  
DataOutputStream output; //输出到文件的输出流 Z| We9%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） MSl&?}Bj  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~;[&K%n  
{ c15r':.5  
siteInfoBean = bean; I:i<>kG  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); L1wZU,o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ym\(PCa5`  
if(tmpFile.exists ()) l7z6i*R  
{ z>G;(F2  
bFirst = false; SG:bM7*1'  
read_nPos(); $Z ]z  
} c` , 2h#  
else nd:E9:  
{ <c+K3P'3?  
nStartPos = new long[bean.getNSplitter()]; ]*3:DU  
nEndPos = new long[bean.getNSplitter()]; D{cZxI  
} `}gdN};  
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} y])).p P  
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public void run() v0#*X5C1'  
{  F~6#LT  
//获得文件长度 ;wR 'z$8  
//分割文件 b:kXNDc  
//实例FileSplitterFetch 44HiTWQS?l  
//启动FileSplitterFetch线程 ong""K4H  
//等待子线程返回 J R$r!hX  
try{ -Wc~B3E|  
if(bFirst) \G>ZkgU  
{ Gf0,RH+  
nFileLength = getFileSize(); {U"^UuU]  
if(nFileLength == -1) x6;j<m5Mjx  
{ 3F+Jdr'  
System.err.println("File Length is not known!"); $*\L4<(  
} ghAi{@s$)  
else if(nFileLength == -2) brSi<  
{ eEl.. y  
System.err.println("File is not access!"); ~e">_;k6  
} 8;8c"'Mn  
else e;VIL 2|  
{ }$kQs!#  
for(int i=0;i<nStartPos.length;i++) A&,,9G<  
{ h2w}wsb0l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Bs8[+Ft5  
} j U[ O  
for(int i=0;i<nEndPos.length-1;i++) r-IT(DzkD  
{ E4i0i!<z  
nEndPos = nStartPos[i+1]; l! v!hUb+  
} &(blN.2  
nEndPos[nEndPos.length-1] = nFileLength; yGj.)$1},@  
} U# JIs  
} zhblLBpeE\  
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L]d-33.c!H  
//启动子线程 <rIz Z'D  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  Paj vb-f  
for(int i=0;i<nStartPos.length;i++) @=Fi7M  
{ zj|WZ=1*Wp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jrMe G.e=D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l=}~v  
nStartPos,nEndPos,i); 'ZP)cI:+X  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g(ogXA1  
fileSplitterFetch.start(); %|"g/2sF[G  
} W# US#<9Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fc_2D|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ts$@s^S]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X"aEJ|y  
nEndPos = " + nFileLength); I+(/TP  
// fileSplitterFetch[nPos.length-1].start(); k1 -~  
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 \e3`/D  
//等待子线程结束 ANi)q$:{  
//int count = 0; {aYY85j  
//是否结束while循环 Gi2$B76<  
boolean breakWhile = false; zj{r^D$  
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while(!bStop) 5ETip'<KT6  
{ Ro(Zmk\t  
write_nPos(); &op
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Utility.sleep(500); eLD|A=X?  
breakWhile = true; rjx6Djo>  

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for(int i=0;i<nStartPos.length;i++) \55VqGyxu9  
{ =ONHKF[UJ  
if(!fileSplitterFetch.bDownOver) yp.[HMRD  
{ 2i{cQ96  
breakWhile = false; 1BHG'
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break; b75$?_+  
} u+H
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} WI> P-D  
if(breakWhile) b89a)k>^g  
break; e=vsuqGT  
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//count++; 7{@l%jx][  
//if(count>4) ZK;zm  
// siteStop(); c9qR'2  
} bHLT}x/Gw  
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System.err.println("文件下载结束！"); M-)RQ-h  
} tZ`Ts}\e  
catch(Exception e){e.printStackTrace ();} ~lNsa".c  
} zZcnijWb  
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//获得文件长度 xx{!3 F  
public long getFileSize() n1 6 `y}  
{ Twn4
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int nFileLength = -1; 7dsefNPb  
try{ H]4Hj  
URL url = new URL(siteInfoBean.getSSiteURL()); dL7E<?l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1I@8A>2^OX  
httpConnection.setRequestProperty("User-Agent","NetFox"); s,#>m*Rh  
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int responseCode=httpConnection.getResponseCode(); gs!(;N\j|  
if(responseCode>=400) ,h"-  
{ 4DZ-bt'  
processErrorCode(responseCode); ifN64`AhRX  
return -2; //-2 represent access is error `u>4\sv  
} g&/T*L  
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String sHeader; WAdCF-S  
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for(int i=1;;i++) %p%%~ewmx  
{ y;/VB,4V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z5ij(RE]  
//Utility.log(in.readLine()); RKPO#qju\F  
sHeader=httpConnection.getHeaderFieldKey(i); 6@DF  
if(sHeader!=null) A}eOFu`  
{ RX/hz|  
if(sHeader.equals("Content-Length")) pz"0J_xDM  
{ $DG?M6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pK0"%eA  
break; P.gb1$7<  
} \rv<$d@L  
} '],J$ge  
else <[w=TdCPs  
break; Ub6jxib  
} -GxaV #{  
} 6j ~#[  
catch(IOException e){e.printStackTrace ();} AK@9?_D  
catch(Exception e){e.printStackTrace ();} %c4Hse#Y  
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Utility.log(nFileLength); 9T<x&  
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return nFileLength; V:y'Qf2M  
} !r<pmr3f@7  
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//保存下载信息（文件指针位置） VVlr*`  
private void write_nPos() =i[\-  
{ q@{Bt{$x  
try{ %^jMj2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X(NLtO w  
output.writeInt(nStartPos.length); 'dn]rV0(C  
for(int i=0;i<nStartPos.length;i++) OGl}-kw  
{ \.-bZ$  
// output.writeLong(nPos); we//|fA<  
output.writeLong(fileSplitterFetch.nStartPos); ^eY!U%.  
output.writeLong(fileSplitterFetch.nEndPos); y@S$^jk.  
} SaO}e  
output.close(); -V77C^()8d  
} iy.p n  
catch(IOException e){e.printStackTrace ();} G"qvz{*  
catch(Exception e){e.printStackTrace ();} {L{o]Ii?g  
} _}Ac n$  
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//读取保存的下载信息（文件指针位置） 5uGq%(24  
private void read_nPos() nfbR P t  
{ GY'%+\*tj  
try{ #jvtUS\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hR?{3d#x2  
int nCount = input.readInt(); Mq156TL  
nStartPos = new long[nCount]; hn GZ=  
nEndPos = new long[nCount]; PJ|P1O36a  
for(int i=0;i<nStartPos.length;i++) me$Z~/Akm  
{ AlaW=leTe  
nStartPos = input.readLong(); 5{X<y#vAC0  
nEndPos = input.readLong(); {UI+$/v#  
} y%cP1y)  
input.close(); hED}h![  
} g wRZ%.Cn  
catch(IOException e){e.printStackTrace ();} `r6,+&  
catch(Exception e){e.printStackTrace ();} UcHJR"M~c  
} Rsm^Z!sn  
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private void processErrorCode(int nErrorCode) rpha!h>w1%  
{ q"lSZ; 'E  
System.err.println("Error Code : " + nErrorCode); -=Q*Ml#I  
} +5*95-;0  
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//停止文件下载 D%pF;XY  
public void siteStop() `4J$Et%S  
{ K\Wkoi5  
bStop = true; iOghb*aW  
for(int i=0;i<nStartPos.length;i++) Rr]Hy^w  
fileSplitterFetch.splitterStop(); tXs\R(?T  
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} jvL[ JI,b  
} NH4#  
//负责部分文件的抓取 IHac:=*Q  
**FileSplitterFetch.java rglXs  
*/ ~q.F<6O  
package NetFox; p8O2Z?\  
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import java.io.*; +~$ ]}%  
import java.net.*; !wVM= z^G  
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public class FileSplitterFetch extends Thread { g*_&  
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String sURL; //File URL Xl#ggub?  
long nStartPos; //File Snippet Start Position A?P_DA  
long nEndPos; //File Snippet End Position r),kDia  
int nThreadID; //Thread's ID IOmfF[  
boolean bDownOver = false; //Downing is over .t
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boolean bStop = false; //Stop identical +I|vzz`ZVr  
FileAccessI fileAccessI = null; //File Access interface KkbDW3-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ow,w$0(D  
{ [RhO$c$[\  
this.sURL = sURL; |/{=ww8|  
this.nStartPos = nStart; SY\ gXO8k  
this.nEndPos = nEnd; ",; H`V  
nThreadID = id; qo bc<-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *.t7G  
} .W!i7  
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public void run() VY4yS*y  
{ _]H&,</  
while(nStartPos < nEndPos && !bStop) aEeodA<(  
{ Z@!+v19^  
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try{ YNF k  
URL url = new URL(sURL); <PH#[dH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5U$0F$BBp  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]N?kG`[  
String sProperty = "bytes="+nStartPos+"-"; ^u ~Q/4  
httpConnection.setRequestProperty("RANGE",sProperty); 0aB;p7~&  
Utility.log(sProperty); igPX#$0XU  
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InputStream input = httpConnection.getInputStream(); z<?)Rq"  
//logResponseHead(httpConnection); )jP1or  
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byte[] b = new byte[1024]; BRiE&GzrF  
int nRead; '~=SzO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /a4{?? #e  
{ 4|DWOQ':  
nStartPos += fileAccessI.write(b,0,nRead); (O3nL.  
//if(nThreadID == 1) -uf|w?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [7Oe3=  
} UP,c|  
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Utility.log("Thread " + nThreadID + " is over!"); HG^'I+Yn  
bDownOver = true; &Z%?!.4j@  
//nPos = fileAccessI.write (b,0,nRead); jNk%OrP]  
} l]8uk^E  
catch(Exception e){e.printStackTrace ();} VMWf>ZU  
} pW3^X=6  
} 6j}9V L77  
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}5"u[Z.  
//打印回应的头信息 Lp9E:D->  
public void logResponseHead(HttpURLConnection con) UJ   
{ k{-Cwo  
for(int i=1;;i++) vEJbA  
{ Q*Pq{]0K  
String header=con.getHeaderFieldKey(i); H/M@t\$Dc  
if(header!=null) cbTm'}R(G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); PdWx|y{%  
Utility.log(header+" : "+con.getHeaderField(header)); 5=ryDrx  
else 6=Otq=WH  
break; _oeS Uzq.  
} oUlVI*~ND  
} A*BeR0(  
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public void splitterStop() xJ.M;SF4  
{ nU7[c| =  
bStop = true; EADqC>  
} w``U=sfmV  
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} GZIa4A  
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/* (#c:b  
**FileAccess.java
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*//文件访问(定位，写) ;RlxD 4p  
package NetFox; jmG~UnM  
import java.io.*; CU!Dhm/U  
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public class FileAccessI implements Serializable{ < =IFcN  
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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 hM
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RandomAccessFile oSavedFile; 5|)W.*Q  
long nPos; =7UsVn#o  
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public FileAccessI() throws IOException [dz _R  
{ =?8@#]G+  
this("",0); 2&cT~ZX&'  
} m9;SrCN_  
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public FileAccessI(String sName,long nPos) throws IOException :g/tZd$G5  
{ RxQ*  
oSavedFile = new RandomAccessFile(sName,"rw"); apn*,7ps65  
this.nPos = nPos; ~"A0Rs=  
oSavedFile.seek(nPos); %(Icz?  
} );YDtGip J  
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public synchronized int write(byte[] b,int nStart,int nLen) 2~[juWbz  
{ [nh>vqum  
int n = -1; m]&SNz=  
try{ t6t!t*jO  
oSavedFile.write(b,nStart,nLen); 7d\QB(~  
n = nLen; K(|}dl:  
} @O~pV`_tD  
catch(IOException e) nJ;.Td  
{ m4Zk\,1m.|  
e.printStackTrace (); -nwypu  
} F"mmLao  
$/ ]
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return n; Dha1/g1q  
} ~$J2g  
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} w32y3~  
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/* 5:?!=<=  
**SiteInfoBean.java J.%IfN  
*/ q.}CU.dp  
package NetFox; ),!q
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public class SiteInfoBean { ugBCBr  
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private String sSiteURL; //Site's URL nr#|b`J]  
private String sFilePath; //Saved File's Path u%!@(eKM-  
private String sFileName; //Saved File's Name 1 -b_~DF  
private int nSplitter; //Count of Splited Downloading File $pz/?>!  
+cRn%ioVi  
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public SiteInfoBean() SS2%qv  
{//nSplitter的缺省值为5 3(UVg!t  
//default value of nSplitter is 5 Fj!U|l\_9  
this("","","",5); H;"4C
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} cH)";]k*-  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V~ _>U}  
{ #LNED)Vg  
sSiteURL= sURL; e#q}F>/L  
sFilePath = sPath; |cY`x(?yP  
sFileName = sName; 9!tW.pK5  
this.nSplitter = nSpiltter; p4)Q&k!  
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} \Og+c%  
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public String getSSiteURL() DL.!G  
{ ?1".;foZ  
return sSiteURL; Dhv3jg;lq  
} B1Oq!k  
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=Runf +}  
public void setSSiteURL(String value) LHmZxi?  
{ .8|X   
sSiteURL = value; t:c.LFrF  
} /L#?zSt  
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public String getSFilePath() qY#6SO`_iy  
{ ~_a-E  
return sFilePath; $]8Q(/mbK  
} F<w/PMb  
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MY/}-*|  
public void setSFilePath(String value)  LIdF 0  
{ Hr4}3.8  
sFilePath = value; O1kl70,`R  
} ]{LjRSV
 
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public String getSFileName() \C1nZk?3  
{ P }uOJVQ_  
return sFileName; -%dCw6aX+  
} {_dvx*M  
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public void setSFileName(String value) Q
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{ TB^$1C  
sFileName = value; *9i{,I@  
} ]
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6aV_@no.C  
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public int getNSplitter() Q5_o/wk  
{ Q
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return nSplitter; Y4(  
} llsfTrp  
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public void setNSplitter(int nCount) yiI1x*^  
{ >"<Wjr8W!$  
nSplitter = nCount; !g.?  
} ei{eTp4HpV  
}  f V(J|  
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cs'{5!i]  
/* gzg_>2Sj  
**Utility.java dq[xwRU1  
*/ a@*\o+Su  
package NetFox; K_-MYs.  
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public class Utility { +2j AC r  
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public Utility() @ry_nKr9  
{ /H==Hm/  
*WT`o>  
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} 7\q~%lDE  
6MkP |vr6  
//线程睡眠 w+{LAS  
public static void sleep(int nSecond)
\'bzt"f$j  
{ O0y_Lm\  
try{ 09Cez\0  
Thread.sleep(nSecond); 0K2`-mL  
} L,@lp  
catch(Exception e) xZv#Es%#  
{ ?3xzd P  
e.printStackTrace (); jalg5`PU0  
} @|%2f@h  
} #lW`{i  
I 2|Bg,e  
//日志 &JI8]JmU)  
public static void log(String sMsg) uRr o?m<  
{ Ez=Olbk  
System.err.println(sMsg); LE>]8[f6S  
} E+w<R
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Y.r+wc]  
h2""9aP!  
public static void log(int sMsg) 8pgEix/M5o  
{ 'X2POay1  
System.err.println(sMsg); (*)hD(C5  
} $ DSZO!pB  
} %1$,Vs<RH  
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Oo%d]8W  
/* 3kMf!VL  
**TestMethod.java /Mu@,)''  
*/ 7x4PaX(  
package NetFox; qm o9G  
sp*v?5lW  
#?9;uy<j.q  
public class TestMethod { R!N%o~C2-  
\)?HJ  
l2P=R)@{  
public TestMethod() ]`+HO
=0  
{ ///xx/weblogic60b2_win.exe p"ZG%Ow5Q]  
try{ P(z++A&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :A'y+MnK<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +&2%+[nBZ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %n:k#  
fileFetch.start(); b`O'1r\Y;  
} d4c8~L H-  
catch(Exception e){e.printStackTrace ();} r? E)obE  
p2$P:!Y)  
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} V /V9B2.$  
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public static void main(String[] args) u($!z^h  
{ <3C*Z"aQ>|  
new TestMethod(); ^qD$z=z-  
} cq/$N  
} 'u |c  
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