http断点续传简单实现（java)

/* ~*&H$6NJS  
**SiteFileFetch.java oi&VgnSk  
*/ d=$Mim  
package NetFox; FJGlP&v<  
import java.io.*; `!3SF|x&  
import java.net.*; @|Cz-J;D  
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public class SiteFileFetch extends Thread { P+ 3G~Sr  
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SiteInfoBean siteInfoBean = null; //文件信息Bean I;,77PxD  
long[] nStartPos; //开始位置 eH'av}  
long[] nEndPos; //结束位置 Jc&{`s^Nu  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Fj8z  
long nFileLength; //文件长度 v|_K/|  
boolean bFirst = true; //是否第一次取文件 EqkN3%IG  
boolean bStop = false; //停止标志 c)6m$5]  
File tmpFile; //文件下载的临时信息 ]NQfX[  
DataOutputStream output; //输出到文件的输出流 .ljnDL/  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jh?H.;**  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y#ap*  
{ _P#
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siteInfoBean = bean; /Iu1L#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); P[G)sA_"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); kf\PioD8  
if(tmpFile.exists ()) l?v86k  
{ jodIv=C  
bFirst = false; '
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read_nPos(); T8?Ghbn  
} 0mYXv4 <  
else ;RZ )  
{ Di,^%  
nStartPos = new long[bean.getNSplitter()]; P8OaoPj  
nEndPos = new long[bean.getNSplitter()]; :_`F{rDB  
} \S `:y?[Y  
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} w8")w*9Lmg  
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public void run() G{As,`{  
{ ih-#5M@  
//获得文件长度 gMi
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//分割文件 //up5R_nx  
//实例FileSplitterFetch kYE9M8s;  
//启动FileSplitterFetch线程 <`8n^m*  
//等待子线程返回 { T/[cu<  
try{ T= 80,  
if(bFirst) f=l rg KE  
{ nmee 'oEw  
nFileLength = getFileSize(); |"q5sym8Y_  
if(nFileLength == -1) {LI=:xJJv  
{ rm'SOJVA  
System.err.println("File Length is not known!"); np|Sy;:  
} f=+
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else if(nFileLength == -2) JMCKcZ%N  
{ &~cBNw|  
System.err.println("File is not access!"); WMDl=6  
} gi3F` m  
else /cUO$m o  
{ %"i(K@  
for(int i=0;i<nStartPos.length;i++) d(ZO6Nr Q  
{ &N$<e(K  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); z#9aP&8Q  
}  h},IF  
for(int i=0;i<nEndPos.length-1;i++) udK%>  
{ X;+sUj8  
nEndPos = nStartPos[i+1]; 1;bh^WMJ  
} >%_\;svZG  
nEndPos[nEndPos.length-1] = nFileLength; pHGYQ;:L  
} B B{$&Oh  
} N@4w! HpJ  
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//启动子线程 $j%'{)gK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; YsC>i`n9  
for(int i=0;i<nStartPos.length;i++) ,C\i^>=  
{ #Qw0&kM7I  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zEX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G{~J|{t\yz  
nStartPos,nEndPos,i); (Bb5?fw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5X:AbF  
fileSplitterFetch.start(); 6D;Sgc5"  
} G6Axs1a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fivw~z|[@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zy?|ODM  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3@_xBz,I.  
nEndPos = " + nFileLength); 0(}t8lc  
// fileSplitterFetch[nPos.length-1].start(); *uRBzO}  
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//等待子线程结束 _gR;=~S  
//int count = 0; 4&lv6`G `  
//是否结束while循环 D(op)]8  
boolean breakWhile = false; C\3rJy(VJ  
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while(!bStop) S&5&];Ag  
{ H\"sgoJ  
write_nPos(); [o#oak{U  
Utility.sleep(500); qCC.^8  
breakWhile = true; h]&GLb&<?  
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for(int i=0;i<nStartPos.length;i++) a#(?P.6  
{ #<"~~2?  
if(!fileSplitterFetch.bDownOver) JPI3[.o  
{ BQHVQs   
breakWhile = false; mkk6`,ov  
break; sRR(`0Zp  
} G^|:N[>B  
} .[KrlfI  
if(breakWhile) oAVnK[EMq`  
break; wc@X.Q[  
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//count++; hp50J  
//if(count>4) #powub  
// siteStop(); z]y.W`i   
} J
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System.err.println("文件下载结束！"); %)8}X>xq  
} =_*Zn(>t`  
catch(Exception e){e.printStackTrace ();} '?' l;#^i<  
} 2DDtu[}  
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//获得文件长度  @tnz]^V  
public long getFileSize() vzAaxk%  
{ epe)a  
int nFileLength = -1; oUlY?x1  
try{ @CL{D:d  
URL url = new URL(siteInfoBean.getSSiteURL()); Y;M|D'y+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1z4OI6$Af  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1~_{$5[X?  
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int responseCode=httpConnection.getResponseCode(); N0Lw}@p  
if(responseCode>=400) ',@3>T**  
{ `:K
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processErrorCode(responseCode); M#6W(|V/  
return -2; //-2 represent access is error ifQ*,+@fxR  
} Wq&if_  
;?iW%:_,  
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String sHeader; DU'`ewLL7  
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for(int i=1;;i++) (k.[GfCbD  
{ 1N-\j0au  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `5.'_3  
//Utility.log(in.readLine()); z'n:@E  
sHeader=httpConnection.getHeaderFieldKey(i); b94DJzL1z  
if(sHeader!=null) |v%YQ R  
{ %)W2H^  
if(sHeader.equals("Content-Length")) &)ChQZA  
{ Do7Tj  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); UKvWJnz  
break; xGg )Y#  
} F^BS/Yag  
} Qbn"=n2  
else lvz7#f L~  
break; `iNSr?N.  
} .@U@xRu7|  
} 5c0 ZRV#  
catch(IOException e){e.printStackTrace ();} \ :sUL!  
catch(Exception e){e.printStackTrace ();} Qd$nH8EDY  
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Utility.log(nFileLength); KwSqKI7]0  
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return nFileLength; ~KX/ Ai  
} SsDmoEeB[  
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//保存下载信息（文件指针位置） 7WS p($  
private void write_nPos() L+i=VGm0  
{ 051E6-  
try{ Z
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output = new DataOutputStream(new FileOutputStream(tmpFile)); #'szP\  
output.writeInt(nStartPos.length); ~-Qw.EdC  
for(int i=0;i<nStartPos.length;i++) s8t;.^1}  
{ CXM
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// output.writeLong(nPos); F/kWHVHU[  
output.writeLong(fileSplitterFetch.nStartPos); #gs`#6 ,'  
output.writeLong(fileSplitterFetch.nEndPos); 29
] G^f>  
} 08\,<9  
output.close(); eJX9_6m-  
} fxHH;hRfv  
catch(IOException e){e.printStackTrace ();} 0 ZKx<]!  
catch(Exception e){e.printStackTrace ();} $Sip$\+*  
} LCKV>3+_#  
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//读取保存的下载信息（文件指针位置） 4p;`C  
private void read_nPos() :{l_FY436  
{ #r\4sVg  
try{ .|fHy  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
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int nCount = input.readInt(); `mJ6K&t$<  
nStartPos = new long[nCount]; j>"@,B g*  
nEndPos = new long[nCount]; J<h$ wM  
for(int i=0;i<nStartPos.length;i++) `l[c_%Bm  
{ .?sx&2R2  
nStartPos = input.readLong(); SZ'R59Ee<  
nEndPos = input.readLong(); flbd0NB  
} ;$wVu|&  
input.close(); Wt-GjxGi  
} bJTBjS-7  
catch(IOException e){e.printStackTrace ();} iz PDd{[  
catch(Exception e){e.printStackTrace ();} z$. 88^  
} `dN@u@[\ks  
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private void processErrorCode(int nErrorCode) =X:Y,?  
{ kxhWq:[c  
System.err.println("Error Code : " + nErrorCode); 0~/_|?]`7  
} 7[XRd9a5(  
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//停止文件下载 :':s@gqr  
public void siteStop() 9qzHS~l  
{ WW~sNC\3`(  
bStop = true; p}~JgEE  
for(int i=0;i<nStartPos.length;i++) ;[OH(
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fileSplitterFetch.splitterStop(); i<Zc"v;  
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} m&&m,6``P  
} {_p_%;  
//负责部分文件的抓取 B[?Ng}<g`  
**FileSplitterFetch.java A$0fKko  
*/ Pu$Tk|  
package NetFox; ;iL#7NG-R  
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import java.io.*; uz jU2  
import java.net.*; @`- 4G2IU}  
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public class FileSplitterFetch extends Thread { >U27];}y  
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String sURL; //File URL )zdQ1
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long nStartPos; //File Snippet Start Position Bn&ze.F  
long nEndPos; //File Snippet End Position n9ej7
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int nThreadID; //Thread's ID Z,Dl` w  
boolean bDownOver = false; //Downing is over M!D3}JRm  
boolean bStop = false; //Stop identical wjB:5~n50k  
FileAccessI fileAccessI = null; //File Access interface .|i.Cq8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 'e'cb>GnA  
{ @<EO`L)Z  
this.sURL = sURL; {fT6O&br  
this.nStartPos = nStart; srrgvG,  
this.nEndPos = nEnd; z5*'{t)  
nThreadID = id; u <v7;dF|s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?J>  
} 7?w*]  
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public void run() E""bTz@  
{ F0Yd@Lk$_  
while(nStartPos < nEndPos && !bStop) dJNe+ MB`  
{ n<R?ffy  
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try{ 59;KQ  
URL url = new URL(sURL); wgGl[_)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y\g3hM  
httpConnection.setRequestProperty("User-Agent","NetFox"); pG;U2wE  
String sProperty = "bytes="+nStartPos+"-"; 3"~!nn0;  
httpConnection.setRequestProperty("RANGE",sProperty); 07{)?1cod4  
Utility.log(sProperty); t&e{_|i#+  
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InputStream input = httpConnection.getInputStream(); R%[ c;i  
//logResponseHead(httpConnection); ,/|T-Ka
 
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byte[] b = new byte[1024]; ]Gq !`O1  
int nRead; ml }{|Yz  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A_q3KB!$=+  
{ _L=h0H l  
nStartPos += fileAccessI.write(b,0,nRead); oE]QF.n#  
//if(nThreadID == 1) AFE~ v\Gz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G2: agqL/  
} 8VXH+5's  
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Utility.log("Thread " + nThreadID + " is over!"); C,|,-CY  
bDownOver = true; or}[h09qA  
//nPos = fileAccessI.write (b,0,nRead); Z=vU}S>r|v  
} OYn}5RN  
catch(Exception e){e.printStackTrace ();} FXkM#}RgNm  
} IF:;`r@%  
} Zp=U W*g^  
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//打印回应的头信息 n,WqyNt*  
public void logResponseHead(HttpURLConnection con) s`~IUNJ@P  
{ gV_}
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for(int i=1;;i++) 4~Q/"hMSkO  
{ >}6%#CAf  
String header=con.getHeaderFieldKey(i); draN0vf  
if(header!=null) wNdisI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V)N%WXG  
Utility.log(header+" : "+con.getHeaderField(header)); u.xnOcOH!  
else \(2sW^fY  
break; sD#.Oq4&]y  
} oW6XF-yM  
} YS"=yye3e  
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public void splitterStop() v mk2{f,g  
{ '?(% Zxw%&  
bStop = true; E+;7>ja  
} </*6wpN  
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} o|["SYIf  
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/* J
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**FileAccess.java 9p(.A$  
*//文件访问(定位，写) +TDw+  
package NetFox; 6qnzBA7  
import java.io.*; 8v%o,"  
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public class FileAccessI implements Serializable{ |@4' <4t  
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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 P-"y3 ZE=  
RandomAccessFile oSavedFile; 7zG_(83)K  
long nPos; [.wYdv35  
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public FileAccessI() throws IOException \bw2u!  
{ #AQV(;r7@  
this("",0); 8bld3p"^  
} ~b8]H|<'Y  
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public FileAccessI(String sName,long nPos) throws IOException -(H0>Ap  
{ ?&1!vz  
oSavedFile = new RandomAccessFile(sName,"rw"); II,8O  
this.nPos = nPos; KPUV@eQ,  
oSavedFile.seek(nPos); TuaBm1S{f  
} h@ryy\9  
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public synchronized int write(byte[] b,int nStart,int nLen) l+^*LqEW2  
{ |&i<bqLw:  
int n = -1; {"KMs[M  
try{ `<d }V2rdz  
oSavedFile.write(b,nStart,nLen); R (n2A$  
n = nLen; &Au@S$ij  
} }k.Z~1y  
catch(IOException e) ncT&G
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{ h<<v^+m  
e.printStackTrace (); K]w'&Qm8W  
} pTLCWbF?  
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return n; |P?*5xPB  
} AFwdJte9e  
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} a9Zq
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/* SOA,kwHRe  
**SiteInfoBean.java 5\VWCI  
*/ c@L< Z`u  
package NetFox; U|R_OLWAg  
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public class SiteInfoBean { q'Pf]
  
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private String sSiteURL; //Site's URL +9sQZB# (  
private String sFilePath; //Saved File's Path X|]AT9W  
private String sFileName; //Saved File's Name >Cq<@$I2EB  
private int nSplitter; //Count of Splited Downloading File mj7#&r,1l  
5*u+q2\F  
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public SiteInfoBean() E|shs=I  
{//nSplitter的缺省值为5 8P\Zo8}v  
//default value of nSplitter is 5 ) ;Y;Q  
this("","","",5); iuul7VR-%  
} Dk51z@  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M x"\5i  
{ z},# ~L6$q  
sSiteURL= sURL; jq0O22 -R  
sFilePath = sPath; W: z;|FF  
sFileName = sName; 5L}/&^E#p  
this.nSplitter = nSpiltter; +G>\-tjSD  
vo{--+{ky!  
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} 4
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public String getSSiteURL() N!tX<u~2  
{ R[+<^s}p/  
return sSiteURL; SOao
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} '8kP.l  
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public void setSSiteURL(String value) M&M6;Ph  
{ _ jlRlt  
sSiteURL = value; P@~yx#G  
} 7tCw*t$  
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public String getSFilePath() HTTC
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{ lPAQ3t!,  
return sFilePath; SSzIih@u  
} E2+`4g@{8<  
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public void setSFilePath(String value) Q22 GIr  
{ +&H4m=D-#a  
sFilePath = value; E' uZA  
} ;}p  
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public String getSFileName() E _|<jy$`  
{ <IW$m!{VG  
return sFileName; @IZnFHN  
} ~pky@O#b  
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public void setSFileName(String value) ;-Aa|aT!  
{ +1!ia]  
sFileName = value; >+T)#.wo&  
} f* wx<  
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public int getNSplitter() bW+:C5'  
{ "d}Gp9+$VY  
return nSplitter; GTxk%   
} MiX43Pk]  
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public void setNSplitter(int nCount) ,<X9Y2B  
{ M D#jj3y  
nSplitter = nCount; 2st3  
} x.4m|f0;  
} :Llb< MY2  
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/* (^>J&[=  
**Utility.java B`sAk %  
*/ ?gXp*>Kg[  
package NetFox; 1{.9uw"2S  
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public class Utility { \GU<43J2uo  
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public Utility() 3$ PV2"  
{ TkF[x%o  
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} >@Kx>cg+  
5IpDeJ$  
//线程睡眠 Zb#u0Tq  
public static void sleep(int nSecond) 3__-nV  
{ /zox$p$?h  
try{ EiaW1Cs  
Thread.sleep(nSecond); wdoR
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} dgP3@`YS  
catch(Exception e) #p{4^  
{ uEx-]F  
e.printStackTrace (); YchH~m
|  
} #rg6,.I)<  
} {
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U%/+B]6jP  
//日志 -ze J#B)C  
public static void log(String sMsg) R^e'}+Z  
{ K.yb ^dg5  
System.err.println(sMsg); 23jwAsSo  
} OcO3v'&  
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public static void log(int sMsg) VS|2|n1<6  
{ DIUjn;>k8  
System.err.println(sMsg); o,wUc"CE  
} 7mfS*aCb  
} 'E.w=7z&  
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/<BI46B\  
/* *n"{J(Jt`  
**TestMethod.java o<!?7g{  
*/ |+"(L#wk  
package NetFox; t3^&;&[  
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public class TestMethod { Xlt|nX~#;  
>KKMcTOYY  
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public TestMethod() (uidNq
 
{ ///xx/weblogic60b2_win.exe )=-szJjXZ  
try{ BD7Ni^qI$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #)VF3T@#'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); a-J.B.A$Z/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Yz93'HDB  
fileFetch.start(); -D~%|).
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} d<x7{?~.DK  
catch(Exception e){e.printStackTrace ();} h@wgd~X9  
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} 6-ils3&  
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public static void main(String[] args) 3irl (;v  
{ '/%H3A#L  
new TestMethod(); H" 7u7l  
} k~z Iy;AZ  
} g#E-pdY  
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