http断点续传简单实现（java)

/* i@/%E~W  
**SiteFileFetch.java qZ<n\Mt  
*/ (u?s@/e:`/  
package NetFox; 5H._Q  
import java.io.*; 6C$+D  
import java.net.*; I gJu/{:y^  
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public class SiteFileFetch extends Thread { W8<QgpV*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean h#zm+([B*  
long[] nStartPos; //开始位置 i}T*| P  
long[] nEndPos; //结束位置 5zS%F: 3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 M.g2y&8  
long nFileLength; //文件长度 DS8HSSD  
boolean bFirst = true; //是否第一次取文件 2?,lr2  
boolean bStop = false; //停止标志 dwn|1%D  
File tmpFile; //文件下载的临时信息 8i6iynR  
DataOutputStream output; //输出到文件的输出流 q
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） o9sQ!gptw  
public SiteFileFetch(SiteInfoBean bean) throws IOException wo9R:kQ  
{ 3r%v@8)!b  
siteInfoBean = bean; 9No6\{[M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6F^/k,(k4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l"8g9z  
if(tmpFile.exists ()) 88u[s@  
{ thPAD+u.3  
bFirst = false; %Vo'\|  
read_nPos();
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} 5T/+pC$e=  
else {Lju7'5L  
{ 3\2&?VAjR  
nStartPos = new long[bean.getNSplitter()]; >(:3H+  
nEndPos = new long[bean.getNSplitter()]; z{R Mb  
} ejg!1*H@n  
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} T3b0"o27  
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public void run() A7QT4h&6  
{ 1drg5  
//获得文件长度 K`=U5vG^  
//分割文件 xgOt%7sb  
//实例FileSplitterFetch "4XjABJ4'  
//启动FileSplitterFetch线程 !@V]H  
//等待子线程返回 s\'t=}0q  
try{ 41R~.?  
if(bFirst) qA}l[:F+#  
{ :MDFTw~|  
nFileLength = getFileSize(); w[2E:Nj  
if(nFileLength == -1) FUI/ A>  
{ Q8TR@0d  
System.err.println("File Length is not known!"); .t^1
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} Fkv284,LM  
else if(nFileLength == -2) W&A^.% 2l  
{ +
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System.err.println("File is not access!"); S?DMeZ{:  
} pDC`Fi  
else i{g~u<DH)Q  
{ oKRI2ni$j9  
for(int i=0;i<nStartPos.length;i++) k8Dk;N  
{ xqT} 9,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b#709VHm  
} w_@6!zm  
for(int i=0;i<nEndPos.length-1;i++) "+
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{ M!G/5:VZ  
nEndPos = nStartPos[i+1]; *"|f!t  
} Z'AjeZyyE  
nEndPos[nEndPos.length-1] = nFileLength; ~Q- /O~  
} i&HU7mP/  
} W__$ i<1  
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a#0*#&?7@  
//启动子线程 &w_8E+YZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y=GD
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for(int i=0;i<nStartPos.length;i++) y]Q/(O  
{ D
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0Dd8c\J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), s$^ 2Cuhv  
nStartPos,nEndPos,i); b#(QZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <{V{2V#  
fileSplitterFetch.start(); _)CCD33$  
} 45+kwo0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MNfc1I_#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g6q[ I8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T5[(vTp  
nEndPos = " + nFileLength); j%!xb><  
// fileSplitterFetch[nPos.length-1].start(); s
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//等待子线程结束 &S^a_L:  
//int count = 0; H8c -/  
//是否结束while循环 y_IF{%i  
boolean breakWhile = false; BQMo*I>I  
q|.0Ja  
h#h)=;  
while(!bStop) ud(w0eX  
{ enMHKN g  
write_nPos(); w
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Utility.sleep(500); <.|
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breakWhile = true; -P]onD  
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for(int i=0;i<nStartPos.length;i++) :2L-Nf  
{ 7r3EMX\#Qm  
if(!fileSplitterFetch.bDownOver) <l)I%1T_c  
{ "jq F  
breakWhile = false; >+BLD  
break; Kn+
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} Xp^71A?>  
} btf]~YN  
if(breakWhile) bmC{d  
break; l%cE o`U  
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r2;+ACwWf_  
//count++; ;>p{|^X0D  
//if(count>4) uoY]@.  
// siteStop(); U_0"1+j
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} Yv;iduc('  
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System.err.println("文件下载结束！"); -1F
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} 9(9\kQj{C  
catch(Exception e){e.printStackTrace ();} 7baQ4QY?n  
} y#{> tC  
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2)`4(38  
//获得文件长度 l;JB;0<s"  
public long getFileSize() "CQ:<$|$  
{ 3}?]G8iL?L  
int nFileLength = -1; ue6&)7:~  
try{ C'z}jM`g  
URL url = new URL(siteInfoBean.getSSiteURL()); gDsb~>rb|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sU?%"q  
httpConnection.setRequestProperty("User-Agent","NetFox"); nrZZkQNI  
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int responseCode=httpConnection.getResponseCode(); 4q^'MZm1  
if(responseCode>=400) i\k>2df  
{ )6-!,D0db  
processErrorCode(responseCode); }W"/h)q  
return -2; //-2 represent access is error ]OA8H[U-eA  
} [RUYH5>Ik  
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String sHeader; .\ces2,  
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for(int i=1;;i++) ^&8xfI
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{ w`K=J!5y2g  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (ft$ R?  
//Utility.log(in.readLine()); [,ns/*f3R  
sHeader=httpConnection.getHeaderFieldKey(i); w>gB&59r  
if(sHeader!=null) G8p6p6*  
{ f>_' ]eM%  
if(sHeader.equals("Content-Length")) Y]{~ogsn$:  
{ 1lQO`CmR6M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \ssqIRk  
break; KP]{=~(  
} 2~*.X^dR  
} S_56!  
else B=+Py%  
break; _ye74$#  
} >a2i%j/T  
} Sy`7})[  
catch(IOException e){e.printStackTrace ();} 5"9!kZ(<  
catch(Exception e){e.printStackTrace ();} [E|%  
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Utility.log(nFileLength); t5WW3$Nf  
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return nFileLength; EAXbbcV  
} 1$ C\`  
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//保存下载信息（文件指针位置） 6` @4i'.  
private void write_nPos() m'.y,@^B  
{ z#elwL6  
try{ i"o %Gc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &ywU^hBh  
output.writeInt(nStartPos.length); =5m~rJ<
{  
for(int i=0;i<nStartPos.length;i++) u
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{ i_6 Y
6  
// output.writeLong(nPos); o&"nF+,  
output.writeLong(fileSplitterFetch.nStartPos); a
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output.writeLong(fileSplitterFetch.nEndPos); ?#P@N4Uw}y  
} g/6>>p`J  
output.close(); =Hwlo!  
} `z{sDe;  
catch(IOException e){e.printStackTrace ();} '&hk?  
catch(Exception e){e.printStackTrace ();} 3=~0m  
} 8%D 2G i  
{:0TiOP5x  
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//读取保存的下载信息（文件指针位置） \_J;i[
  
private void read_nPos() a8laPN  
{ ~*Kk+w9H<  
try{ ;HbAk`\1A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^
6(Nu|6\@  
int nCount = input.readInt(); ?m>!P@ M  
nStartPos = new long[nCount]; [=q&5'FY0  
nEndPos = new long[nCount]; ^J-\s_)"  
for(int i=0;i<nStartPos.length;i++) SV0h'd(b  
{ B78e*nNS#2  
nStartPos = input.readLong(); _)?59  
nEndPos = input.readLong(); n6]8W^g  
} %RS8zN  
input.close(); =7212('F  
} HSsG0&'-Y  
catch(IOException e){e.printStackTrace ();} p`-Oz]  
catch(Exception e){e.printStackTrace ();} ic(`Ev  
} J-wF2*0r<  
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private void processErrorCode(int nErrorCode) !m<v@SmL\  
{ xaG( 3  
System.err.println("Error Code : " + nErrorCode); \T]'d@Wyd  
} p,K]`pt=  
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//停止文件下载 dF<GuS;l5  
public void siteStop() 6./3w&D;  
{ Hlj_oDL  
bStop = true; lOuO~`,J  
for(int i=0;i<nStartPos.length;i++) kMP3PS  
fileSplitterFetch.splitterStop(); Mo~zq.  
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} &K.js  
} \7U'p:h=U  
//负责部分文件的抓取 %!r@l7<  
**FileSplitterFetch.java U8
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*/ ?6T\uzL +%  
package NetFox; g#/"3P2H  
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import java.io.*; &;wNJ)
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import java.net.*; _aj,tz  
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public class FileSplitterFetch extends Thread { P")1_!  
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String sURL; //File URL jC}2>_#m(  
long nStartPos; //File Snippet Start Position 1HS43!  
long nEndPos; //File Snippet End Position @&xWd{8'  
int nThreadID; //Thread's ID sm?V%NX&  
boolean bDownOver = false; //Downing is over QDdH5EfY  
boolean bStop = false; //Stop identical gql^Inx<  
FileAccessI fileAccessI = null; //File Access interface x^]J^L45  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2{;~Bgd  
{ s5
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this.sURL = sURL; %;MM+xVVX  
this.nStartPos = nStart; NA;OT7X[  
this.nEndPos = nEnd; SWWeN#Q  
nThreadID = id; w1J%%//(h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~,O&A B
  
} V+Y;  
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public void run() !<#,M9 EA&  
{ .TpM3b#r  
while(nStartPos < nEndPos && !bStop) /=IBK`  
{ &~{0@/
 
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try{ fuao*L]  
URL url = new URL(sURL); N,ysv/zq7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Nm4 h  
httpConnection.setRequestProperty("User-Agent","NetFox"); /|#";QsPN  
String sProperty = "bytes="+nStartPos+"-"; }$X/HK  
httpConnection.setRequestProperty("RANGE",sProperty); ]b'"l  
Utility.log(sProperty); P?/Mrz   
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InputStream input = httpConnection.getInputStream(); m4~>n(  
//logResponseHead(httpConnection); u#Y#,:{  
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byte[] b = new byte[1024]; _Qd CV`  
int nRead; &Fy})/F3v  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6O\a\z  
{ h"ZR`?h  
nStartPos += fileAccessI.write(b,0,nRead); L)yc_ d5  
//if(nThreadID == 1) !}I+)@~
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ={[9kR i  
} Ce`#J6lT  
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Utility.log("Thread " + nThreadID + " is over!"); Gk-49|qIV  
bDownOver = true; VbfTdRD-  
//nPos = fileAccessI.write (b,0,nRead); hA:RVeS{  
} O0RV>Ml'&  
catch(Exception e){e.printStackTrace ();} .{,fb  
} ,0\Pr  
} 4D=^24f`0  
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//打印回应的头信息 *Eg[@5;QA  
public void logResponseHead(HttpURLConnection con) _MxKfah'  
{ B:rzM:BQ  
for(int i=1;;i++) Scd_tw.]|  
{ F~;UD<<"H  
String header=con.getHeaderFieldKey(i); ":W$$w<  
if(header!=null) x.kIzI5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d<_#Q7]I4  
Utility.log(header+" : "+con.getHeaderField(header)); LVe[N-K  
else JxmFUheLt  
break; "(+p1  
} IrMxdF~c  
} mTgsvC  
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public void splitterStop() xua E\*m  
{ U^ ;H{S  
bStop = true; gn)>(MG  
} aW*8t'm;m'  
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} ;/ASl<t,  
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/* a?1Ml>R6P  
**FileAccess.java > JP}OS  
*//文件访问(定位，写) pKkBAr,  
package NetFox; HApjXv!U[  
import java.io.*; 5gg
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public class FileAccessI implements Serializable{ QE4TvnhK  
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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 l|sC\;S  
RandomAccessFile oSavedFile; RN"Ur'+  
long nPos; (-%1z_@Y  
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public FileAccessI() throws IOException Uu0  
{ t{Wu5<F:  
this("",0); )NmYgd~%  
} `h='FJ/!  
;.{J>Q/U,  
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public FileAccessI(String sName,long nPos) throws IOException H:]'r5sw  
{ Wa
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oSavedFile = new RandomAccessFile(sName,"rw"); $ #bWh  
this.nPos = nPos; M$Ow*!DfP  
oSavedFile.seek(nPos); .f-s+J&ED  
} }9~U5UXWU  
c

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public synchronized int write(byte[] b,int nStart,int nLen) 
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{ g=e~YM85  
int n = -1; e'T|5I0K  
try{ (w1$m8`=  
oSavedFile.write(b,nStart,nLen); s(pNg?R  
n = nLen; d8J(~$tXQN  
} n+D93d9LP  
catch(IOException e) [!Zyp`:  
{ !`0 El',gY  
e.printStackTrace (); 9w.ZXd  
} Q?V'3ZZF!  
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return n; v~:'t\n  
} j2s{rQQ  
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} #'8'5b  
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/* NeR1}W  
**SiteInfoBean.java hxkwT  
*/ _18Aek  
package NetFox; $fAZ^   
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public class SiteInfoBean { \[<8AV"E-'  
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private String sSiteURL; //Site's URL Ntlbn&lc;D  
private String sFilePath; //Saved File's Path i|!W;2KL5  
private String sFileName; //Saved File's Name qlC4&82=Q  
private int nSplitter; //Count of Splited Downloading File .o)  
Sz-TarTF  
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public SiteInfoBean() q.ZkQN+  
{//nSplitter的缺省值为5 O|0V mm  
//default value of nSplitter is 5 6+/BYN!&4  
this("","","",5); 4VP$,|a  
} .5!Q(  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o!zo%#0;#)  
{ qPn!.m$/  
sSiteURL= sURL; Lklb  
sFilePath = sPath; Bpp(5  
sFileName = sName; WDF6.i ?  
this.nSplitter = nSpiltter; J<MuWgx&  
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$|VD+[jSV  
} '5\?l:z  
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public String getSSiteURL() E
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{ j`QXl  
return sSiteURL; Sr+ &  
} %Mf3OtPiJW  
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~|&To>  
public void setSSiteURL(String value) ]uXmug  
{ wDKA1i%G  
sSiteURL = value; h3V; J  
} >S@><[C  
)<`/Aaie  
BHR(B]EI  
public String getSFilePath() e#^vA$d  
{ wUH:l  
return sFilePath; @6VkNe9  
} X4/3
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%";ap8J04F  
public void setSFilePath(String value) +<'>~lDg  
{ hy"=)n(  
sFilePath = value; `gdk,L]  
} v
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}i52MI1-XP  
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public String getSFileName() +oiuulA  
{ R]N"P:wf@  
return sFileName; Lv@'v4.({  
} {;3a^K  
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public void setSFileName(String value) M<ba+Qn$  
{ ?GGBDql  
sFileName = value; .=@CF8ArG  
} &Y-jK<  
*
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public int getNSplitter() M<xF4L3]  
{ =z#j9'n$@  
return nSplitter; g3c,x kaO  
} Z@bKYfGM  
`86})xz{  
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public void setNSplitter(int nCount) @VnK/5opS  
{ rhC x&L  
nSplitter = nCount; 2[1lwV
  
} 35Fs/Gf-n  
} >+Y@rj2  
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/* _FzA
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**Utility.java \1oN't.  
*/ O[ug7\cl+  
package NetFox; mBDzc(_\$'  
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public class Utility { 5$c*r$t_RK  
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3
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public Utility() bEb+oRI  
{ v|:TYpku3  
nw=:+?  
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} du&9mOrr  
6,(S}x YDZ  
//线程睡眠 R!2E`^{Wl  
public static void sleep(int nSecond) vpoJ{TPO  
{ 14yzGhA  
try{ {$'oKJy*  
Thread.sleep(nSecond); dyt.(2  
} )pw53,7>aN  
catch(Exception e) uwu`ms7z 2  
{ `}#n
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e.printStackTrace (); }h=3[pe
}  
} 4x_# 1 -  
} u=ZZ;%Rvd  
]Mj N)%hT  
//日志 URMxCL^"  
public static void log(String sMsg) >uJU25)|  
{ W@61rT}c  
System.err.println(sMsg); #g]eDU-[  
} hv)d  
mf\@
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] jycg@=B  
public static void log(int sMsg) vzZ"TSP  
{ 6IKi*}  
System.err.println(sMsg); I~25}(IDZ"  
} ]_2<uK}fg  
} r-5xo.J'  
_Q}vPSJviC  
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/* _q`f5*Z[  
**TestMethod.java >H,PST  
*/ *[tLwl.  
package NetFox; Q=#Wk$1.  
*zWf8X  
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public class TestMethod { V0y_c^x  
x_#'6H\1ga  
bOK0^$k  
public TestMethod() 5/i]Jni  
{ ///xx/weblogic60b2_win.exe .>@]Im  
try{ xi
=Qxgx0I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :{~TG]4M  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <ugy-vSv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tFX!s;N[  
fileFetch.start(); WP4"$W
 
} ,pa=OF  
catch(Exception e){e.printStackTrace ();} lfte  
@O)1Hnm  
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} R^Y_i  
|4F'Zu}g>  
|/;X-+f8  
public static void main(String[] args) "PC9[i  
{ k9iB-=X?4s  
new TestMethod(); }Pj;9ivz  
} &Tk@2<5=  
} @!%HEs!# #  
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