http断点续传简单实现（java)

/* g[$4a4X  
**SiteFileFetch.java J+r:7NvZ  
*/ )%vnl~i!  
package NetFox; jzd)jJ0M  
import java.io.*; O#?@'1  
import java.net.*; a9y+FCA  
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public class SiteFileFetch extends Thread { y7| 3]>Z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean MIdViS.g  
long[] nStartPos; //开始位置 C1o^$Q|j  
long[] nEndPos; //结束位置 #Fz/}lO  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 aKz:hG  
long nFileLength; //文件长度 ^MO})C  
boolean bFirst = true; //是否第一次取文件 bW^C30m  
boolean bStop = false; //停止标志 Z7p!YTA  
File tmpFile; //文件下载的临时信息 VG|FjD  
DataOutputStream output; //输出到文件的输出流 nYE%@Up  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .I.B,wH8  
public SiteFileFetch(SiteInfoBean bean) throws IOException i>e?$H,/  
{ z]R%'LGu  
siteInfoBean = bean; xSq{pxX  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); u=t.1eS5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); mM.YZUX  
if(tmpFile.exists ()) F}?4h Dt  
{ 7=gcdfW,;x  
bFirst = false; xJ9aFpTC  
read_nPos(); **JBZ\'  
} &O#,"u/q`  
else 7 j6<  
{ 1E
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nStartPos = new long[bean.getNSplitter()]; nF$HWp&gt  
nEndPos = new long[bean.getNSplitter()]; QD%!a{I  
} Kr;;aT0P  
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}
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public void run() pQ>|dH+.  
{ 3g3f87[  
//获得文件长度  ?tA%A  
//分割文件 )qe rA  
//实例FileSplitterFetch {@6:kkd  
//启动FileSplitterFetch线程 -Aojk8tc  
//等待子线程返回 PQp/&D4K  
try{ B
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if(bFirst) QiK-|hFj  
{ n'0r (  
nFileLength = getFileSize(); HLOrDlj7  
if(nFileLength == -1) 7hTpjox2  
{ 5z =}o/?  
System.err.println("File Length is not known!"); k7j.VpN9  
} 4XAs^>N+  
else if(nFileLength == -2) *<X1M~p$  
{ (;&}\OX6nm  
System.err.println("File is not access!"); JOJuGB-d  
} \Y>b#*m(4  
else (T%?@'\  
{ *@p"  
for(int i=0;i<nStartPos.length;i++) m2"wMt"*V  
{ 1wFW&|>1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); drc-5{M  
} "{\xBX~oM  
for(int i=0;i<nEndPos.length-1;i++) $v #  
{ Y[]I!Bc  
nEndPos = nStartPos[i+1]; {@F'BB\  
} 4\5i}MIS0  
nEndPos[nEndPos.length-1] = nFileLength; /_})7I52  
} m#8(l{3|  
} ]
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//启动子线程 .{\eco  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; qZ'2M.;  
for(int i=0;i<nStartPos.length;i++) S3l^h4  
{ K4jHha  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "w%:5~u9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Zp^O1&\SK?  
nStartPos,nEndPos,i); s .<.6t:G4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w;yzgj:n&f  
fileSplitterFetch.start(); rhcax%
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} bm 4RR
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =Y81h-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l)*(UZ"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0FtwDM))  
nEndPos = " + nFileLength); a#"orc j  
// fileSplitterFetch[nPos.length-1].start(); sYBmL]Hr  
]"b:IWPeI  
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//等待子线程结束 @fYVlHT%E  
//int count = 0; >5#}/G&  
//是否结束while循环 *U,JQ  
boolean breakWhile = false; \fUX_0k9,  
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while(!bStop) tiE|%jOzt  
{ :MY=Q]l  
write_nPos(); Q5T3  
Utility.sleep(500); 6ICW>#fI`  
breakWhile = true; 'I&0$
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for(int i=0;i<nStartPos.length;i++) <O 0Q]`i  
{ mf$YsvPq*+  
if(!fileSplitterFetch.bDownOver) -yBKA]"<I  
{ E&zf<Y  
breakWhile = false; MGsQF#6]  
break; ^J#*sn  
} O^`EuaL  
} ,\iHgsZ  
if(breakWhile) tngB;9c+w  
break; \/YRhQ  
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//count++; %S;AM\o4  
//if(count>4) <[)-Q~Gg5  
// siteStop(); #4O4,F>e  
} &>,]YrU  
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+
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System.err.println("文件下载结束！"); @d0f+9d  
} ih".y3  
catch(Exception e){e.printStackTrace ();} KhfADqji|  
} XQ}J4J~Vm  
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//获得文件长度 isL zgN%  
public long getFileSize() e9{0hw7  
{ YUEyGhkMV{  
int nFileLength = -1; hz4?
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try{ N9_* {HOy  
URL url = new URL(siteInfoBean.getSSiteURL()); uKP4ur@1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lf7bx}P*  
httpConnection.setRequestProperty("User-Agent","NetFox"); *uyP+f2O  
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int responseCode=httpConnection.getResponseCode(); f"FFgQMkv  
if(responseCode>=400) 7yfh4-1M  
{ m}wn+R  
processErrorCode(responseCode); gU
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return -2; //-2 represent access is error />S^`KSTM  
} ae sk.  
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String sHeader; Rsfb?${0G  
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for(int i=1;;i++) #-;W|ib%z  
{ T ?[28|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); JI-i7P  
//Utility.log(in.readLine()); 2xLtJR4L  
sHeader=httpConnection.getHeaderFieldKey(i); @vlP)"
 
if(sHeader!=null) X 61|:E  
{ ~9+01UU^  
if(sHeader.equals("Content-Length")) $v@$C
4  
{ (I}owr5:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); o0R?vnA=  
break; q~R8<G%YK  
} py'vD3Q  
} oFU:]+.+D  
else :'DyZy2Fd  
break; Czjb.c:a.Y  
} z{L'7  
} &TH
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catch(IOException e){e.printStackTrace ();} `MI;.t  
catch(Exception e){e.printStackTrace ();} 05LkLB  
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Utility.log(nFileLength); oVpZR$  
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return nFileLength; h vYRAQR:  
} NuQ!huh  
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//保存下载信息（文件指针位置） MR1I"gqE}I  
private void write_nPos() GI]\  
{ iM<$ n2t  
try{ Lm4`O%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \}jA1oy  
output.writeInt(nStartPos.length); >_2~uF@pb  
for(int i=0;i<nStartPos.length;i++) bh.&vp.kP  
{ O^MI073Q>t  
// output.writeLong(nPos); R0RxcBtG  
output.writeLong(fileSplitterFetch.nStartPos); XjN4EDi+E  
output.writeLong(fileSplitterFetch.nEndPos); ./F:]/Mt  
} VgNB^w  
output.close(); JUr t%2  
} 'OA*aQ=K  
catch(IOException e){e.printStackTrace ();} R&Lqaek&W  
catch(Exception e){e.printStackTrace ();} ,MXU]{  
} j,j|'7J%  
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//读取保存的下载信息（文件指针位置） @[g7\d  
private void read_nPos() L?h?LZnq  
{ [Qnf]n\FJ  
try{ Vc9rc}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "-=fi 'D  
int nCount = input.readInt(); #yH+ENp0   
nStartPos = new long[nCount]; q!c=f!U?\l  
nEndPos = new long[nCount]; 5_;-Qw  
for(int i=0;i<nStartPos.length;i++) {U;yW)  
{ %M iv8  
nStartPos = input.readLong(); X)KCk2Ax  
nEndPos = input.readLong(); ]CzK{-
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} ~q3O,bb{  
input.close(); xxur4@p!  
} 3=d%WPgQ  
catch(IOException e){e.printStackTrace ();} \\R}3 >Wc  
catch(Exception e){e.printStackTrace ();} u+j\PWOtm  
} s`$}xukT  
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private void processErrorCode(int nErrorCode) 8%K{lg"  
{  WwB_L.{  
System.err.println("Error Code : " + nErrorCode); VO0:4{-  
} :(A&8<}-6  
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//停止文件下载 2K9X(th1  
public void siteStop() gML8lu0)  
{ vxZ'-&;t  
bStop = true; z6R|1L 1  
for(int i=0;i<nStartPos.length;i++) GNJ/|9
  
fileSplitterFetch.splitterStop(); D3C7f'  
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} p3Ux%/ZqPV  
} tpGT~Y(  
//负责部分文件的抓取 _8.TPB]n
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**FileSplitterFetch.java .aT@'a{F  
*/ v":q_w<k  
package NetFox; uA#K59E+  
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import java.io.*; Rt?CE jy  
import java.net.*; 66&uK|  
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public class FileSplitterFetch extends Thread { ;0Z-  
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String sURL; //File URL U\P4ts  
long nStartPos; //File Snippet Start Position &{? M} 2I  
long nEndPos; //File Snippet End Position (?Mn_FNE|  
int nThreadID; //Thread's ID yn\c;Z  
boolean bDownOver = false; //Downing is over K[icVT2v~  
boolean bStop = false; //Stop identical He=C\"  
FileAccessI fileAccessI = null; //File Access interface AAQ!8!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tM]Gu?6  
{ i6WPf:#wr  
this.sURL = sURL; $U?]^  
this.nStartPos = nStart; g8.z?Ia#5Z  
this.nEndPos = nEnd; SEM?vQ 0"}  
nThreadID = id; DP),~8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 nook/7]  
} UDI\o1Rbp  
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public void run() C4(xtSJSd!  
{ )zxb]Pg+  
while(nStartPos < nEndPos && !bStop) (e'8>Pv  
{ yzK<yvN  
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try{ q%x i>H.:{  
URL url = new URL(sURL); l+6c|([  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z 0
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httpConnection.setRequestProperty("User-Agent","NetFox"); e#/&A5#Ya  
String sProperty = "bytes="+nStartPos+"-"; lC#wh2B6  
httpConnection.setRequestProperty("RANGE",sProperty); wKpBH}  
Utility.log(sProperty); S%MDQTM  
?7NSp2aq2A  
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InputStream input = httpConnection.getInputStream(); Bg),Q8\I  
//logResponseHead(httpConnection); 6#Z]yk+p  
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byte[] b = new byte[1024]; _{`Z?lt  
int nRead; bdWdvd:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) = zmxki  
{ (W h)Ov"  
nStartPos += fileAccessI.write(b,0,nRead); 4vbGXb}!  
//if(nThreadID == 1) 9KX% O-'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [TA.|7&  
} ;-`NT` #2  
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Utility.log("Thread " + nThreadID + " is over!"); nnn\  
bDownOver = true; XB!qPh.  
//nPos = fileAccessI.write (b,0,nRead); 8;pY-j #  
} 02Vfg42  
catch(Exception e){e.printStackTrace ();} X`_tm3HC  
} xw
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} 8a*&,W  
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//打印回应的头信息 SAq.W"ri  
public void logResponseHead(HttpURLConnection con) w=fWW^>bP  
{ Lx>[`QT  
for(int i=1;;i++) t#(=$  
{ ]0T*#U/P  
String header=con.getHeaderFieldKey(i); EeMKo  
if(header!=null) a0)w/A&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <O=0^V  
Utility.log(header+" : "+con.getHeaderField(header)); BDf M4  
else sxr,]@  
break; ,ASNa^7/>  
} F_0D)H)N@  
} H_@6!R2  
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public void splitterStop() B?&0NpVD  
{ uxn+.fA  
bStop = true; >"IG\//I  
} -3yK>\y=|  
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} 5|0/$ SWd*  
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/* BegO\0%+  
**FileAccess.java EGI$=Y  
*//文件访问(定位，写) s@$0!8sxm  
package NetFox; !X: TieyVu  
import java.io.*; j]&
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public class FileAccessI implements Serializable{ G~C-tAB  
|WS@q'
  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
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RandomAccessFile oSavedFile; qJs_ahy(  
long nPos; e.L&A|  
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public FileAccessI() throws IOException Wn6m$=  
{ clyp0`,7  
this("",0); _;^x^  
} HOu$14g  
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public FileAccessI(String sName,long nPos) throws IOException c}$>UhLe  
{ 6oQ7u90z*  
oSavedFile = new RandomAccessFile(sName,"rw"); N/WtQSl  
this.nPos = nPos; c
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oSavedFile.seek(nPos); vv)w@A:Vn)  
} ORKJy)*"  
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public synchronized int write(byte[] b,int nStart,int nLen) ~t2"L|i  
{ X&aQR[X  
int n = -1; uL7}JQ,  
try{ nm\f$K>Pg  
oSavedFile.write(b,nStart,nLen); c"knzB vy  
n = nLen; 20$Tky_  
} `}P9[HP  
catch(IOException e) ! 1?u0  
{ K)l*$h&-  
e.printStackTrace (); )IK%Dg(v  
} m,hqq%qz  
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return n; `ba<eT':  
} PDc4ok`)  
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} HW_2!t_R  
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/* *3RD\.jPX  
**SiteInfoBean.java O*/Utl  
*/ /;Cx|\  
package NetFox; LfrjC@_y  
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public class SiteInfoBean { j;Lp@~M  
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private String sSiteURL; //Site's URL )"P.n-aF  
private String sFilePath; //Saved File's Path 1Ogtzf  
private String sFileName; //Saved File's Name },5LrX`L  
private int nSplitter; //Count of Splited Downloading File W^:g_  
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public SiteInfoBean() `i!-@WN"  
{//nSplitter的缺省值为5 {iLr$89  
//default value of nSplitter is 5 '+^XL6$L  
this("","","",5); ]%Whtj.,x7  
} hA~5,K0b  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) X~; *zYd5  
{ $U_1e'
  
sSiteURL= sURL; 6l>016 x  
sFilePath = sPath; 99q$>nx,w  
sFileName = sName; 7x |Pgu(  
this.nSplitter = nSpiltter; "Jyb?5  
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} R&R{I/;i*.  
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public String getSSiteURL() !%C&hH\  
{ @(tiPV  
return sSiteURL; Q
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} $J:~jY/J  
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public void setSSiteURL(String value) Cd'SPaR  
{ ;%i.@@:IQ  
sSiteURL = value; j~9,Ct  
} {[B`q  
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public String getSFilePath() k{$Mlt?&-  
{ ] i\a[3  
return sFilePath; ^Ul*
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} |a Ht6F  
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public void setSFilePath(String value) d`+cNKf  
{ nR~L$Wu5_a  
sFilePath = value; ]O;Rzq{D(  
} =l9H]`T/  
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public String getSFileName() 4q5bW+$Xj  
{ |[lM2  
return sFileName; lN^} qg><  
} vN4g#,<  
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public void setSFileName(String value) APksY!  
{ nMHs5'_y  
sFileName = value; Y;'7Ek)  
} 6,|)%~VUm  
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public int getNSplitter() "i1~YE  
{ Ls^$E  
return nSplitter; Et
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} ;2;Kq)j_=  
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public void setNSplitter(int nCount) 29#;;n}p  
{ daZY;_{"o  
nSplitter = nCount; Q pY:L  
} =e,2/Ep{i  
} AjZ@hid  
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h&vq}  
/* %!HmtpS  
**Utility.java Z\y@rp\l  
*/ xla9:*pPn  
package NetFox; ; . c]0  
PU^Z7T);  
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public class Utility { '7{0k{  
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public Utility() Ss&R!w9p  
{ ht S5<+Y  
#{l+I(M  
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} Px}#{fkS  
9frS!AQ  
//线程睡眠 t HPC  
public static void sleep(int nSecond) xS,#TU;)Ol  
{ ]v 6u
  
try{ r 8,6qP[  
Thread.sleep(nSecond); R/iw#.Yy  
} u[^(s_  
catch(Exception e) 1k\1U  
{ ?(!$vqS`f(  
e.printStackTrace (); /cr.}D2O  
} `{/z\  
} G;MgrA#\  
>'8.>f  
//日志 }yU,_:  
public static void log(String sMsg) ^c^9kK'
 
{ {JzX`Z30l  
System.err.println(sMsg); Vl?R?K=`~J  
} s0.yPA  
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public static void log(int sMsg) C 9,p-  
{ 6lq7zi}'w  
System.err.println(sMsg); l<{]%=Qg  
} dLal15Pb  
} M\8FjJ>9  
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/* xue-5 '  
**TestMethod.java F)Yn1&a#H  
*/ RWXj)H)w  
package NetFox; 9 YU7R)  
Uz\B^"i|  
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public class TestMethod { OsAXHjX}  
_d]w)YMO  
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public TestMethod() 91%+Bf()J6  
{ ///xx/weblogic60b2_win.exe }`Q'!_`  
try{  #d*mG =  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r['T.yo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,u{d@U^)3@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (OYR, [*  
fileFetch.start(); >;HbDp  
} g 6>RyjN  
catch(Exception e){e.printStackTrace ();} @o44b!i  
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} ?;|$R   
xh@H@Q\  
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public static void main(String[] args) %6L!JN  
{ {+z+6i  
new TestMethod(); ^P:9iu)+]~  
} *0l^/jqn:  
} _7]5Q  
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