http断点续传简单实现（java)

/* ]"q9~  
**SiteFileFetch.java =^ZDP1h/}  
*/ IE]? WW5  
package NetFox; <<WqL?8W  
import java.io.*; ^-nL!>FYY  
import java.net.*; c`,'[Q5(O  
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public class SiteFileFetch extends Thread { l;7T.2J'Z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1#tFO  
long[] nStartPos; //开始位置 !1m7^3l7j  
long[] nEndPos; //结束位置 8SGqDaRt  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |
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long nFileLength; //文件长度 kLE("I:7  
boolean bFirst = true; //是否第一次取文件 U\y:\+e l  
boolean bStop = false; //停止标志 ly9tI-E  
File tmpFile; //文件下载的临时信息 Nhf@Y}Cu  
DataOutputStream output; //输出到文件的输出流 e92,@  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） KwAc Ga}J  
public SiteFileFetch(SiteInfoBean bean) throws IOException pG&#xRk  
{ aoUz_7  
siteInfoBean = bean; 3kzO VZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .RW&=1D6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *(g0{V  
if(tmpFile.exists ()) eL" +_lW  
{ @oKW$\  
bFirst = false; k^@dDLr"  
read_nPos(); #IvHxSo&  
} .~O- <P#  
else A'6-E{  
{ "UYlC0 S\  
nStartPos = new long[bean.getNSplitter()]; HkPdqNC&  
nEndPos = new long[bean.getNSplitter()]; n:"0mWnL$y  
} l~Hu#+O  
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} w!_6*  
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public void run() <s=i5t My5  
{ DFMf"_p  
//获得文件长度 ]!>tP,<`'  
//分割文件 H
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//实例FileSplitterFetch {zIcEN$ ~  
//启动FileSplitterFetch线程 ##6u  
//等待子线程返回 Ak kth*p  
try{ )">uI\bi  
if(bFirst) oM^VtH=>  
{ z!G?T(SpA  
nFileLength = getFileSize(); l@:&0id4I  
if(nFileLength == -1) ,K15KN.'  
{ RF[Uy?es  
System.err.println("File Length is not known!"); \_)[FC@  
} M{t/B-'4  
else if(nFileLength == -2) :z-?L0C=0  
{ fl8eNiE|  
System.err.println("File is not access!"); .4J7 ^l  
} 9fy[%M  
else 7Y.mp9,  
{ C1==a FD  
for(int i=0;i<nStartPos.length;i++) 3!op'X!  
{ Y41b8.|P+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); kx%\Cz  
} o&$Of  
for(int i=0;i<nEndPos.length-1;i++) T@xaa\bzg  
{ V'FKgzd  
nEndPos = nStartPos[i+1]; #Xk/<It  
} 8I~*9MUp  
nEndPos[nEndPos.length-1] = nFileLength; {
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} soOfk!b  
} o'_
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//启动子线程 1RauI0d*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Bs
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for(int i=0;i<nStartPos.length;i++) _"t"orD6  
{ |RH^|2:x9Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,f~)CXNT?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kl|m @Nxp
 
nStartPos,nEndPos,i); BPSie0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [:/mjO K  
fileSplitterFetch.start(); ky{@*fg.  
} =d$m@rc0r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iU|X/>k?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); x<5;#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4D[(X=FSU  
nEndPos = " + nFileLength); !jR 1!i  
// fileSplitterFetch[nPos.length-1].start(); p'kB1)~|  
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//等待子线程结束 Wb5n> *  
//int count = 0; [+!~RV_  
//是否结束while循环 !jg< S>S5  
boolean breakWhile = false; f3*SIKi  
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*|
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while(!bStop) lQL/I[}  
{ B$G9#G6pZ  
write_nPos(); 4|hfzCjMI  
Utility.sleep(500); 7g4IAsoD  
breakWhile = true; ~X-v@a  
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for(int i=0;i<nStartPos.length;i++) _=K\E0I.m  
{ uyoV)  
if(!fileSplitterFetch.bDownOver) 6
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{ cS>xT cj  
breakWhile = false; c3)6{  
break; }-@h H(  
} $e%m=@ga  
} RijFN.s  
if(breakWhile) { 3Qlx/6<  
break; g6H`uO  
t; @T~%  
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//count++; BSY7un+`:  
//if(count>4) km,@y
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// siteStop(); nu X`>Oy  
} *>T@3G.{Rm  
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System.err.println("文件下载结束！"); ?:7.3{|Aq  
} vv
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catch(Exception e){e.printStackTrace ();} QSvgbjdE  
}
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*X2dS {  
//获得文件长度 iwfH~  
public long getFileSize() ={I(i6  
{ }O:l]O`  
int nFileLength = -1; qJK6S4O]  
try{ U3pMv|b  
URL url = new URL(siteInfoBean.getSSiteURL()); [ak[ZXC,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mpzm6Ieu  
httpConnection.setRequestProperty("User-Agent","NetFox"); oYX#VX  
mW#p&{  
:+ AqY(Gz  
int responseCode=httpConnection.getResponseCode(); ~Dj_N$_+9  
if(responseCode>=400) Lmc"qFzK  
{ tj:>o#D  
processErrorCode(responseCode); O*1la/~m  
return -2; //-2 represent access is error fn.}LeeS>  
} N lB%Qu  
b|U3\Fmc  
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String sHeader; 5xc-MkIRL  
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for(int i=1;;i++) 0*:4@go0}i  
{ XtIY8wsP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6S?*z `v  
//Utility.log(in.readLine()); (oB9$Zz!t  
sHeader=httpConnection.getHeaderFieldKey(i); $B@K  
if(sHeader!=null) #.<(/D+  
{ AeEF/*  
if(sHeader.equals("Content-Length")) bAL!l\&2  
{ A"T*uv|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T]?QCf  
break; p"q4R2_/jh  
} tH9BC5+r}  
} `BY&&Bv#?  
else vH vwH  
break; Nk shJ2  
} %|3NCyJ*7  
} 6M@m`c  
catch(IOException e){e.printStackTrace ();} Zc*gRC  
catch(Exception e){e.printStackTrace ();} ^4tz*i  
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Utility.log(nFileLength); vU, ]UJ}  
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return nFileLength; Sv03="&  
} 0& ?/TSC  
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//保存下载信息（文件指针位置） N2`u ]*"0  
private void write_nPos() J
/^|
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{ 3,{tGNl|  
try{ /yL:_6c-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \:91BQP c  
output.writeInt(nStartPos.length); ]73BJ  
for(int i=0;i<nStartPos.length;i++) \B D'"  
{ qGKQrb,K  
// output.writeLong(nPos); FrD,)Ad8Q  
output.writeLong(fileSplitterFetch.nStartPos); .{LJ  
output.writeLong(fileSplitterFetch.nEndPos); LxxFosi8  
} #zc{N"!  
output.close(); j?P8&Fm<  
} ){XG%nC  
catch(IOException e){e.printStackTrace ();} JheF}/Bx  
catch(Exception e){e.printStackTrace ();} UZqk2D  
} V7i1BR8
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//读取保存的下载信息（文件指针位置） a |+q:g0M  
private void read_nPos() 4)~GHb  
{ i:,37INMt  
try{ lBnG!!VrWa  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); N}j^55M_]  
int nCount = input.readInt(); ;COZH
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nStartPos = new long[nCount]; R?$Nl  
nEndPos = new long[nCount]; C!aK5rqhv  
for(int i=0;i<nStartPos.length;i++) |{H-PH*Iz  
{ ~F9WR5}]  
nStartPos = input.readLong(); ^ql+l~  
nEndPos = input.readLong(); Ga}&%  
} J2adA9R/,  
input.close(); kQMALS@R  
} tL~?)2uEN  
catch(IOException e){e.printStackTrace ();} hh>mX6A  
catch(Exception e){e.printStackTrace ();} ckPI^0A!  
}  *$o{+YP  
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private void processErrorCode(int nErrorCode) CJu3h&Rp  
{ |lhVk\X  
System.err.println("Error Code : " + nErrorCode); SmYY){AQ/  
} F,-S&d  
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0 SeDBs  
//停止文件下载 , *A',  
public void siteStop() *eo<5YUHt  
{ wIT}>8o  
bStop = true; )Vb_0n=^  
for(int i=0;i<nStartPos.length;i++)  ?[G!6  
fileSplitterFetch.splitterStop(); -O-qEQd  
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} C
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} 2v6QUf  
//负责部分文件的抓取 DIurFDQSS  
**FileSplitterFetch.java Ge]2g0  
*/ ;f7;U=gl,  
package NetFox; ) b vZ~t+^  
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import java.io.*; Q@-7{3  
import java.net.*; BI,j/SRK  
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public class FileSplitterFetch extends Thread { =@d IM  
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n)
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String sURL; //File URL PDnwaK   
long nStartPos; //File Snippet Start Position zi*2>5g  
long nEndPos; //File Snippet End Position `2@t) :  
int nThreadID; //Thread's ID o(I[_oUy\  
boolean bDownOver = false; //Downing is over 007SA6xq  
boolean bStop = false; //Stop identical [fU2$(mT+  
FileAccessI fileAccessI = null; //File Access interface )MKzAAt~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException / 1jb8w'  
{ ;O2r
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this.sURL = sURL; |?!Ew# w  
this.nStartPos = nStart; D+.h*{gD  
this.nEndPos = nEnd; a N|MB
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nThreadID = id; :>.~"uWo{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G2%%$7Jj  
} ^
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public void run() ]&3UF?  
{ x-5XOqD{'  
while(nStartPos < nEndPos && !bStop) f-?00*T  
{ M<,E[2op  
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try{ s wdW70  
URL url = new URL(sURL); ,?+rM ;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "mnWqRpX  
httpConnection.setRequestProperty("User-Agent","NetFox"); F(8>"(C  
String sProperty = "bytes="+nStartPos+"-"; dE+xU(\,w  
httpConnection.setRequestProperty("RANGE",sProperty); Syn>;FX  
Utility.log(sProperty); 9'I I!  
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InputStream input = httpConnection.getInputStream(); n:GK0wu.s  
//logResponseHead(httpConnection); I-NzGx2u  
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byte[] b = new byte[1024]; *sqq]uD  
int nRead; .Z}ySd:X  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h'x|yy]@3  
{ Ch`XwLY9  
nStartPos += fileAccessI.write(b,0,nRead); ;(Q4x"?I  
//if(nThreadID == 1) 6=kA  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D5]sf>~  
} 8VJUaL@  
xV'\2n=1T  
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Utility.log("Thread " + nThreadID + " is over!"); TE4{W4I  
bDownOver = true; <a|$Bl  
//nPos = fileAccessI.write (b,0,nRead); Ctxs]S tU%  
} SLL%XF~/Sb  
catch(Exception e){e.printStackTrace ();} J'O</o@e  
} Z@=1-l  
} wj/\!V!  
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//打印回应的头信息 Da!A1|"  
public void logResponseHead(HttpURLConnection con) <LDVO'I0!  
{ gRuNC=sR  
for(int i=1;;i++) A e&t#,)  
{ [0D( PV(n  
String header=con.getHeaderFieldKey(i); pq6}q($Rk  
if(header!=null) KDW%*%!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Vh:%e24Z  
Utility.log(header+" : "+con.getHeaderField(header)); \
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else AHP_B&s,Qe  
break; lkK+Fm  
} @X_x?N  
} 2*-s3 >VK  
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public void splitterStop() 15_OtK  
{ _PrK6M@"L  
bStop = true; .N8AkQ(Ok  
} <jT6|2'  
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} %^m6Q!
  
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/* pGz-5afL  
**FileAccess.java \~1M\gZP  
*//文件访问(定位，写) w: ~66 TCI  
package NetFox; q_5k2'4K  
import java.io.*; 716JnG>  
IMjnj|Fj  

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public class FileAccessI implements Serializable{ >&tPIrz  
&'4id[$9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 5YaTE<G  
RandomAccessFile oSavedFile; OWFLw  
long nPos;
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public FileAccessI() throws IOException &IM;Yl  
{ (Bd8@}\u_  
this("",0); NH$a:>  
} SsfnBCVR  
tK6z#)  
@.T '>;izr  
public FileAccessI(String sName,long nPos) throws IOException "o/:LCE  
{ @ 9D, f  
oSavedFile = new RandomAccessFile(sName,"rw"); &,2h=H,M  
this.nPos = nPos; 7jT]J  
oSavedFile.seek(nPos); 1q<BYc+z  
} D(D:/L8T,  
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public synchronized int write(byte[] b,int nStart,int nLen) 2J =K\ L  
{ LFob1HH*8  
int n = -1; 9D++SU2:}  
try{ )f9f_^;  
oSavedFile.write(b,nStart,nLen); X>j% y7v  
n = nLen; Oemi}  
} `:!mPNW#  
catch(IOException e) ~isrE;N1|  
{ k/YEUC5  
e.printStackTrace (); q?g4**C  
} m'k.R j  
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return n; @dQIl#  
} I.TdYSB  
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} e
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u HqPb8  
/* cS/\&%7u  
**SiteInfoBean.java x2/\%!mt  
*/ a}
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package NetFox; &U ]L@]x  
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public class SiteInfoBean { DcA{E8Y  
*,X;4?:,  
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private String sSiteURL; //Site's URL 0P^RciC f  
private String sFilePath; //Saved File's Path (:Rj:8{  
private String sFileName; //Saved File's Name AJt*48H*G  
private int nSplitter; //Count of Splited Downloading File "2q}G16K  
&{NN!X  
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public SiteInfoBean() x zu)``?  
{//nSplitter的缺省值为5 VVO C-:  
//default value of nSplitter is 5 P:vAU8d>  
this("","","",5); {/G~HoY1i  
} Ac
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]3]I`e{  
{ ^WQ.' G5Q  
sSiteURL= sURL; #qY`xH'>  
sFilePath = sPath; hp+=UnW  
sFileName = sName; )isz }?Dj  
this.nSplitter = nSpiltter; NpqMdd   
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} F7lhLly  
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public String getSSiteURL() 8)HUo?/3  
{ UZ7Zzc#g  
return sSiteURL; L#mf[a@pCn  
} HZC^Q7]hy  
fTd=}zY  
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public void setSSiteURL(String value) NovF?kh2  
{ "/[xak!g  
sSiteURL = value; low 0@+Q  
} >Lj0B%^EvM  
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public String getSFilePath() xR}^~14Bz  
{ U Hh  
return sFilePath; (~ro_WC/I  
} ,Z*&QR  
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public void setSFilePath(String value) 4{4VC"fa  
{ cB#5LXbCE  
sFilePath = value; *P2_l Q=  
} 3gtQS3$4s  
;
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public String getSFileName() ChzKwYDY  
{ C$?gt-tJ'  
return sFileName; L!G]i;=:  
} MJ"ug8N  
{2"8^;  
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public void setSFileName(String value) 7u7`z%  
{ B8A-|S!,U  
sFileName = value; zA/tHlKc  
} APY^A6^:j  
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;PM(q<@\  
public int getNSplitter() &[71~.Od  
{ K|[p4*6  
return nSplitter; D>tex/Of3  
} ,5}%_  
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public void setNSplitter(int nCount) q,S[[{("  
{ -;]m4R)z  
nSplitter = nCount; V$w
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} 2OT RP4U  
} 6L5j  
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/* xAJ N(8?  
**Utility.java 9~3;upWu!  
*/ v *'anw&Z  
package NetFox; aia`mO]  
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public class Utility { |q|?y`X4/  
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public Utility() 1M@OBfB8  
{ VZveNz@]r  
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} ?XCFRt,ol  
\e)>]C}h  
//线程睡眠 gR5 EK$  
public static void sleep(int nSecond) jGm`Qg{<  
{ ky4;7R
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try{ `G/%U~  
Thread.sleep(nSecond); )ZZjuFQJ)  
} wPr9N}rf  
catch(Exception e) Ygeg[S!7  
{ 8M6 Xd]{%  
e.printStackTrace (); M~/Pk7CC  
} b"4'*<=au  
} '%Fg+cZN\  
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//日志 -d-vzri  
public static void log(String sMsg) ~,YxUn8@  
{ f%,Vplb  
System.err.println(sMsg); ,gO}H)v]t  
} Fh8 8DDJ  
L i g7Ac,  
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public static void log(int sMsg) ]S  
{ gm^j8B  
System.err.println(sMsg); 6DkFIkS  
} *sJT\J$D[  
} gWk?g^KJL  
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/* Fal##6B  
**TestMethod.java EKgY  
*/ r!+..c  
package NetFox;
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public class TestMethod { ;{
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public TestMethod() QG1+*J76b@  
{ ///xx/weblogic60b2_win.exe !l(D0 C  
try{ ?8U#,qq#`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s7d4)A%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); NZb}n`:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "1P[D'HV4|  
fileFetch.start(); AONEUSxJ  
} : Iq  
catch(Exception e){e.printStackTrace ();} Tv[h2_+E  
a Fh9B\n  
y:
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} Sj'Iz #  
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public static void main(String[] args) C^IPddw>  
{ W5*Kq^6Pd  
new TestMethod(); b)+;=o%  
} w!%"b03q  
} 0:iR=S  
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