http断点续传简单实现（java)

/* 1wP-  
**SiteFileFetch.java <z!CDg4  
*/ ksN+?E4w  
package NetFox; }I2@%tt?  
import java.io.*; fOMW"myQ  
import java.net.*; PuZf/um  
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public class SiteFileFetch extends Thread { O~^"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]h5Yg/sms  
long[] nStartPos; //开始位置 9& 83n(m  
long[] nEndPos; //结束位置 GJqJlgHe  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \0f{S40  
long nFileLength; //文件长度 W0]gLw9*  
boolean bFirst = true; //是否第一次取文件 i0$kit  
boolean bStop = false; //停止标志 ZXuv CI  
File tmpFile; //文件下载的临时信息 %GS(:]{n  
DataOutputStream output; //输出到文件的输出流 #: [<iSk  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9 o&`5  
public SiteFileFetch(SiteInfoBean bean) throws IOException rq/I` :  
{ L');!/:  
siteInfoBean = bean; :d#VE-e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); AQiwugs  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); eXf22;Lz  
if(tmpFile.exists ()) b8LLr;oQw  
{ 
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bFirst = false; O
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read_nPos(); :HwA 5Z#  
} )(384@'"u  
else A'&K/)Z  
{ -u
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nStartPos = new long[bean.getNSplitter()]; ptZ <ow&  
nEndPos = new long[bean.getNSplitter()]; ?TKRjgW`@_  
} E`uY1B[c  
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} pxh"B\"4*  
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public void run() Nu?-0>  
{ K%RxwM  
//获得文件长度 #a8B/-  
//分割文件  VN\W]jT  
//实例FileSplitterFetch (j3xAA  
//启动FileSplitterFetch线程 suzZdkMA  
//等待子线程返回 65aK2MS@  
try{ !74S  
if(bFirst) W|g4z7Pb  
{ hj.a&%  
nFileLength = getFileSize(); --c"0,7  
if(nFileLength == -1) ='
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{ zp%Cr.)$  
System.err.println("File Length is not known!"); TO?R({yx*  
} 7OJ'){R$  
else if(nFileLength == -2) Gf<'WQ[  
{ ikvWh<=>H  
System.err.println("File is not access!"); qtQ6cqLd  
} u*ObwcI/Bn  
else u /\EtSH  
{ Dw<bn<e-  
for(int i=0;i<nStartPos.length;i++) SX# e:_  
{ `u teg=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); X6@WwM~qz  
} ~3WF,mW  
for(int i=0;i<nEndPos.length-1;i++) OZ~5*v  
{ %~E ?Z!_W  
nEndPos = nStartPos[i+1]; UZJCvfi  
} &N\jG373  
nEndPos[nEndPos.length-1] = nFileLength; qfMo7e@6*  
} [8*jw'W|[  
} ^!<BQP7  
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//启动子线程 r[b(I@T+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; SfaQvs
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for(int i=0;i<nStartPos.length;i++) to DG7XN}  
{ ASk|A!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yEhTNBa*h{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z:sg}  
nStartPos,nEndPos,i); 4O)1uF;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v{ 0=  
fileSplitterFetch.start(); x"gd8j]s  
} %B5wH_p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }:KEj_~.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); b2OQtSr a  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =IQ5<;U3  
nEndPos = " + nFileLength); #AL=f'2=f  
// fileSplitterFetch[nPos.length-1].start(); DkvF5c&  
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//等待子线程结束 pxCK;]  
//int count = 0; }}\vV}s  
//是否结束while循环 C8 xZ;V]  
boolean breakWhile = false; pu 7{a  
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while(!bStop) jU9$Ehg I  
{ ~,oMz<iMV  
write_nPos(); 3c]b)n~Y  
Utility.sleep(500); gT0BkwIV  
breakWhile = true; VFURAYS  
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for(int i=0;i<nStartPos.length;i++) >aj7||K  
{ > dI LF  
if(!fileSplitterFetch.bDownOver) ^h~x)@=  
{ `lO[x.[  
breakWhile = false; kT"Kyd  
break; +'I+o5*  
} B&[M7i  
} W;'!g
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if(breakWhile) VcSVu  
break; 2\jPv`Ia  
L
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/ zB0J?  
//count++; =/y]d<g  
//if(count>4) a1+#3X.  
// siteStop(); w[S pw<Z  
} ^=RffrlZU  
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System.err.println("文件下载结束！"); zMm#Rhn  
} 4W#vP
  
catch(Exception e){e.printStackTrace ();} |Lf"6^@yh  
} rvb
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//获得文件长度 R`DKu=  
public long getFileSize() Nn~~!q  
{ TgmnG/Z  
int nFileLength = -1; El[)?+;D  
try{ jV>ra
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URL url = new URL(siteInfoBean.getSSiteURL()); B8V>NvE~o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [y'f|XN  
httpConnection.setRequestProperty("User-Agent","NetFox"); 723bkJw V  
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int responseCode=httpConnection.getResponseCode(); K;>9ZZtl  
if(responseCode>=400) v9w'!C)b  
{ AX;8^6.F3  
processErrorCode(responseCode); 0?\Zm)Q~(  
return -2; //-2 represent access is error im9G,e  
} wsIW |@  
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String sHeader; PE}:ybsX  
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for(int i=1;;i++) G7qG$wd8h  
{ P"y`A}Bx  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); / ';0H_  
//Utility.log(in.readLine()); juka0/  
sHeader=httpConnection.getHeaderFieldKey(i); zR1^I~ %  
if(sHeader!=null) @z4*.S&tz  
{ 544X1Ww2  
if(sHeader.equals("Content-Length")) Pe3@d|-,MU  
{ #(#Wv?r6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4e~A1-  
break; #A1Z'y0  
} ko.(pb@+  
} R?~Yp?B^  
else =j5
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break; -Zf@VW,NI  
} CFzNwgv]z  
} Rot@x r7Hc  
catch(IOException e){e.printStackTrace ();} kP#B5K_U|  
catch(Exception e){e.printStackTrace ();} h]+C.Eqnt#  
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Utility.log(nFileLength); 3D!5T8 @  
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return nFileLength; <j*;.yyC  
} iOR_[y,  
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//保存下载信息（文件指针位置） 8$85^Of  
private void write_nPos() zVXC1u9B  
{ Ir`eL  
try{ xy5lE+E_U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,&jhlZ i  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) { /K.3  
{ WN{ 9  
// output.writeLong(nPos); 0fF(Z0R,  
output.writeLong(fileSplitterFetch.nStartPos); Pz>s6 [ob  
output.writeLong(fileSplitterFetch.nEndPos); !c}O5TI|#  
} Hyb3 ;yQ  
output.close(); _/uFsYC  
} K/tRe/t}  
catch(IOException e){e.printStackTrace ();} 6-yd]("  
catch(Exception e){e.printStackTrace ();} OMWbZ>jB  
} U1DXeh~V  
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//读取保存的下载信息（文件指针位置） 0f

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private void read_nPos() u.d).da  
{ pP*zq"o  
try{ C\/xl#e<@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); co~Pyj  
int nCount = input.readInt(); :=/85\P0SU  
nStartPos = new long[nCount]; <j&DK2u=i  
nEndPos = new long[nCount]; p2n0Z\2  
for(int i=0;i<nStartPos.length;i++) @
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{ ';TT4$(m  
nStartPos = input.readLong(); b8V~S'6VqO  
nEndPos = input.readLong(); tZ} v%3  
} c(:f\Wc3Z  
input.close(); U*(izD  
} ^T ?RK"p  
catch(IOException e){e.printStackTrace ();} U]^HjfX\  
catch(Exception e){e.printStackTrace ();} *AoR==:ya  
} O4r0R1VQM  
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private void processErrorCode(int nErrorCode) /tP|b_7O  
{ BGOuDKz9C  
System.err.println("Error Code : " + nErrorCode); v1BDP<qU2  
} 
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//停止文件下载 RIb4!!',c  
public void siteStop() )-0kb~;|  
{ $nb[G$  
bStop = true; 3a?o3=  
for(int i=0;i<nStartPos.length;i++) (8Bk;bd  
fileSplitterFetch.splitterStop(); x^kp^ /f  
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} ue4Vcf  
} w8kOVN2b  
//负责部分文件的抓取 -R57@D>j\  
**FileSplitterFetch.java  Fy`(BF\  
*/ iz8Bf;  
package NetFox; _CW(PsfY  
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import java.io.*; \^ZlG.  
import java.net.*; P%{
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public class FileSplitterFetch extends Thread { Gl
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String sURL; //File URL uT}' Y)m  
long nStartPos; //File Snippet Start Position 5]n[]FW  
long nEndPos; //File Snippet End Position S`#w+C#EW  
int nThreadID; //Thread's ID -j73Wz  
boolean bDownOver = false; //Downing is over G]+&!4  
boolean bStop = false; //Stop identical k`0>36  
FileAccessI fileAccessI = null; //File Access interface )3~{L;q
 
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 
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{ ptDY3n~'  
this.sURL = sURL; BRlT7grgq  
this.nStartPos = nStart; Pa~)"u8  
this.nEndPos = nEnd; ~(Q)"s\1I  
nThreadID = id; :^kZ.6Q@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^r*r w=  
} -7S g62THS  
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public void run() UD8op]>L  
{ xZ6~Ma2z  
while(nStartPos < nEndPos && !bStop) vH#huZA?7  
{ g=;%  
#=6E\&NC  
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try{ kL$!E9  
URL url = new URL(sURL); B?4boF?~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n}'=yItVL1  
httpConnection.setRequestProperty("User-Agent","NetFox"); vU767/  
String sProperty = "bytes="+nStartPos+"-"; 95YL]3V  
httpConnection.setRequestProperty("RANGE",sProperty); S<4c r  
Utility.log(sProperty);  /% M/  
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InputStream input = httpConnection.getInputStream(); u/M+u;  
//logResponseHead(httpConnection); w,h`s.AN  
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byte[] b = new byte[1024]; !Cr(Pe]  
int nRead; $4/yZaVb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .u4 W /  
{ ig/%zA*Bo  
nStartPos += fileAccessI.write(b,0,nRead); -?mfE+kt  
//if(nThreadID == 1) Z/t+8;TMR,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jh ]i]7r  
} #)C[5?{SNq  

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Utility.log("Thread " + nThreadID + " is over!"); ,6om\9.E@  
bDownOver = true; {buo^kgj`]  
//nPos = fileAccessI.write (b,0,nRead); @}@Z8$G^  
} O*0l+mop  
catch(Exception e){e.printStackTrace ();} YhDtUt}?  
} B oC5E#;G  
} W3 'q\+  
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//打印回应的头信息 \=6l9Lrj>h  
public void logResponseHead(HttpURLConnection con) &ge "x{,?  
{ \'|>p/5I  
for(int i=1;;i++) mG
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{ i(>4wK!!  
String header=con.getHeaderFieldKey(i); ;*:Pw?'  
if(header!=null) tE)suU5Y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); prTw'~(B  
Utility.log(header+" : "+con.getHeaderField(header)); FLGk?.x$\  
else fpFhn  
break; R)mu2^  
} [uI|DUlI6o  
} Bh;7C@dq  

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public void splitterStop() Q0&H#xgt  
{ cVv;Jn  
bStop = true; p$PKa.Y3  
} X)7x<?DAy  
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} J2'Nd'  
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/* 0@H|n^Md#  
**FileAccess.java |j#C|V%kV  
*//文件访问(定位，写) 0tEYU:Qu  
package NetFox; my4giC2a  
import java.io.*; _OuWB"  
 Kfh|  
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public class FileAccessI implements Serializable{ .ys6"V|31  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 y0'R
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RandomAccessFile oSavedFile; PYM(Xz$  
long nPos; vK_?<>  
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public FileAccessI() throws IOException 1:f9J  
{ CS==A57I  
this("",0); li0i"  
} eS<lwA_  
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public FileAccessI(String sName,long nPos) throws IOException BV>\ McI+  
{ .pN`;*7`  
oSavedFile = new RandomAccessFile(sName,"rw"); 0},PJ$8x  
this.nPos = nPos; [&&1j@LQ*  
oSavedFile.seek(nPos); m0cP(  
} rzh#CnL3  
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public synchronized int write(byte[] b,int nStart,int nLen) z#]Jv!~EPE  
{ v(EEG/~  
int n = -1; (&+kl q  
try{ 0Sgaem`  
oSavedFile.write(b,nStart,nLen); :yeq(oK,  
n = nLen; dv.(7Y7.x  
} fp[|M  
catch(IOException e) mxz-4.  
{ 0el9&l9Ew  
e.printStackTrace (); &8]d
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} HmiJ~C_v`:  
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return n; qL6 |6-?  
} Y@b.sMg{  
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} >|twyb  
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/* +TQ47Zc  
**SiteInfoBean.java hA33K #bC  
*/ *g[^.Sg  
package NetFox; /Rg*~Ers *  
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public class SiteInfoBean { o9F/y=.r=  
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private String sSiteURL; //Site's URL Z| V`B `  
private String sFilePath; //Saved File's Path EpFQ|.mQ  
private String sFileName; //Saved File's Name {6~l$  
private int nSplitter; //Count of Splited Downloading File Um: Hrjw  
/k<WNZM  
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public SiteInfoBean() !kE-_dY6)  
{//nSplitter的缺省值为5 ;ByOth|9P  
//default value of nSplitter is 5 /6h(6 *JI  
this("","","",5); CC@.MA@9N  
} ?_Q/}@`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9\]^|?zQ`  
{ -$WYj"  
sSiteURL= sURL; L30$%G|  
sFilePath = sPath; e}.^Tiwd]  
sFileName = sName; k31I ysh  
this.nSplitter = nSpiltter; ^8@Iyh
  
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} 7 <Q5;J&;  
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public String getSSiteURL() * ;Cy=J+  
{ ltD37QZQ  
return sSiteURL; 3l3'bw2  
} YJl("MZ  
61jI  
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public void setSSiteURL(String value) !V,{_(LT  
{ {FG|\nPw  
sSiteURL = value; EoxQ */  
} e&qh9mlE  
^4`Px/&  
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public String getSFilePath() * C6a?]  
{ i![dPM  
return sFilePath; (>I`{9x>6  
} l+g9 5mjP  
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public void setSFilePath(String value) !ZI7&r`u;  
{ ;x8k[p~2  
sFilePath = value; jD`d#R  
} ,ML[Wr'2  
I~9hx*!%%  
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public String getSFileName() S.d^T](  
{ ?w+Ix~k  
return sFileName; Zt&6Ua[Y}  
} @bnG:np  
K&U7H:  
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public void setSFileName(String value) =l0Jb#d  
{ NSFs\a@1  
sFileName = value; ~~6^Sh60g  
} yGsz2T;w  
B-T/V-c7  
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public int getNSplitter() n]u<!.X  
{ yH<$k^0r*  
return nSplitter; EgDQ+( -  
} H=\!2XS  
)5.C]4jol  
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public void setNSplitter(int nCount) ph#tgLJ  
{ `)Z!V?&!  
nSplitter = nCount; JB&\i#  
} b77>$[xB  
} @mBX~ ?=Z3  
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/* f*24)Wn<  
**Utility.java l?q%?v8  
*/ %Jf<l&K.`  
package NetFox; *k1<: @%e  
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public class Utility { 1<<kA:d  
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public Utility() ;_(PVo  
{ 4 8{vE3JY  
i9D0]3/>  
k,
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} q;:6_Qr  
B:\Uw|Mf  
//线程睡眠 }=2;  
public static void sleep(int nSecond) 7rC uu*M  
{ PDLpNTBf  
try{ {h KjD"?  
Thread.sleep(nSecond); ?9X&tK)E-  
} ne>g?"Pex{  
catch(Exception e) LjH*rjS4  
{ i"j(b|?
e  
e.printStackTrace (); pW]4bx@E  
} gXH[$guf  
} kGUJ9Du  
vw)7 !/#  
//日志 u?[ q=0.J7  
public static void log(String sMsg) 3F#+~^2  
{ C P3<1~  
System.err.println(sMsg); er.CDKD%L  
} :vL1}H<  
1H,g=Y4f%  
7 ua6l[c  
public static void log(int sMsg) 8v)_6p(<x8  
{ EOoZoVdzx  
System.err.println(sMsg); O`$#Pg  
} lI/0:|l  
} 7DfTfTU6  
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/* }N*>QR5K  
**TestMethod.java ]}UgS+g>$  
*/ e\b`n}nC  
package NetFox; PjIeZ&p  
=D^TK-H  
s6}Xt=j  
public class TestMethod { SjEdyN#  
!4rPv\
  
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public TestMethod() ~=Ncp9ej#  
{ ///xx/weblogic60b2_win.exe rz(0:vxwA  
try{ ?v-1zCls  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); K+T.o6+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;p ]y)3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E&B{5/rv  
fileFetch.start(); 8)VgS&B~  
} c[ht`!P  
catch(Exception e){e.printStackTrace ();} 3g~^LZ66  
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} Uw<&Wm`'  
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~B$b)`*  
public static void main(String[] args) Y1dVM]l  
{ "*7C`y5&P  
new TestMethod(); 1>r ,vD&  
} 0 3~Ikll  
} r Db>&s3  
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