http断点续传简单实现（java)

/* 4L
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**SiteFileFetch.java 5
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*/ Y.KJP ?  
package NetFox; h pKrP  
import java.io.*; <V1y^EW0  
import java.net.*; yF@72tK  
%(A@=0r#  
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public class SiteFileFetch extends Thread { PX>>h}%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -Ic<.ix  
long[] nStartPos; //开始位置 -GZ:}<W6+  
long[] nEndPos; //结束位置
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 8SOfX^;o  
long nFileLength; //文件长度 Wxzh'c#\8  
boolean bFirst = true; //是否第一次取文件 v-&@c  
boolean bStop = false; //停止标志 D!rD-e  
File tmpFile; //文件下载的临时信息 "Tnmn@  
DataOutputStream output; //输出到文件的输出流 3U4h>T@s|  
'k9Qd:a}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Z)!#+m83>-  
public SiteFileFetch(SiteInfoBean bean) throws IOException %TYe]^/'y  
{ Rja>N)MzBf  
siteInfoBean = bean; '#u=wyp  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0)Q*u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qk=OodEMK  
if(tmpFile.exists ()) ;nw}x4Y[  
{ /E^j}H{  
bFirst = false; f{+X0Oj  
read_nPos(); tvOyT6]  
} M5c *vs  
else  U92?e}=]  
{ .(Tf$V  
nStartPos = new long[bean.getNSplitter()]; $D;-;5[-/r  
nEndPos = new long[bean.getNSplitter()]; Gdv{SCV  
} QRHM#v S  
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* TByAa{  
} kb[+II  
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public void run() TGzs|-  
{ >K*TgG6!X  
//获得文件长度 rnQ9uNAu  
//分割文件 , %A2wV  
//实例FileSplitterFetch )F m'i&F_  
//启动FileSplitterFetch线程 } QpyU%  
//等待子线程返回 sfR0wEqI  
try{ Fia
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if(bFirst) rq|>z.  
{ 9 =D13s(C  
nFileLength = getFileSize(); 9d8U
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if(nFileLength == -1) fKNDl\SD  
{ K}8wCS F  
System.err.println("File Length is not known!"); J<-2dvq  
} Z&5cJk W  
else if(nFileLength == -2) -)[~%n#X+t  
{ G\#dMCk?  
System.err.println("File is not access!"); k(dNHT  
} $j&2bO5M  
else O4T_p=Xc  
{ N:U

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for(int i=0;i<nStartPos.length;i++) ;fB!/u  
{ w"AO~LF  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); v<E_n;@9k  
} oB%j3aAH  
for(int i=0;i<nEndPos.length-1;i++) M7c53fz  
{ 5Eu`1f?  
nEndPos = nStartPos[i+1]; Z[9f8/6<b  
} seA=7c5E  
nEndPos[nEndPos.length-1] = nFileLength; /OeOL3Y  
} :s#&nY  
} YQaL)t$0  
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//启动子线程 w C-x'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; tNYCyw{K  
for(int i=0;i<nStartPos.length;i++) c1h?aP  
{ crU]P $a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :JCe,1!3@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]lA.?  
nStartPos,nEndPos,i); .1h1J   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M3YC@(N% k  
fileSplitterFetch.start(); 8g6G},Y0  
} `.YMbj#T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E[tEW0ub  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #$v,.Yk  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", yOE N*^6  
nEndPos = " + nFileLength); ^vc#)tm5p  
// fileSplitterFetch[nPos.length-1].start(); uY:u[  
J#Agk^Y 5  
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//等待子线程结束 g42f*~l  
//int count = 0; uEdeA'*^  
//是否结束while循环 /^b=| +Do  
boolean breakWhile = false; qQe23,x@5  
@^^,VgW[  
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while(!bStop) |1UJKJwX  
{ y5N,~@$r  
write_nPos(); { u1\M  
Utility.sleep(500); y-vQ4G5F|  
breakWhile = true; }bYk#6KX  
5Cl;h^R|m  
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K  
for(int i=0;i<nStartPos.length;i++) Uc5BNk7<
=  
{ \O+Hmi^  
if(!fileSplitterFetch.bDownOver) ux1SQ8C*  
{ >?ckBU9  
breakWhile = false; [-w+ACV~  
break; ~%u;lr  
} ePe/@g1K*  
} "U iv[8B  
if(breakWhile) hlBqcOpkKg  
break; )}4xmf@gl  
6q@VkzF  
AHdh
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//count++; U[c
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//if(count>4) jmva0K},SE  
// siteStop(); 99?: 9g  
} pR7D3Q:^7  
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]L9$JTGF`w  
System.err.println("文件下载结束！"); {KM5pK?,BJ  
} q|kkdK|N/Y  
catch(Exception e){e.printStackTrace ();} VB@M=ShKK  
} H(ds  
~19&s
~  
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//获得文件长度 THz=_
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public long getFileSize() mY!&*nYn|  
{ ,B$m8wlI|  
int nFileLength = -1; 8?&!@3n  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); h0Ilxa   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {{Z3M>Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); dS~#Lzm  
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5)<}a&;{  
int responseCode=httpConnection.getResponseCode(); {%XDr,myd  
if(responseCode>=400) Z
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{ dnstm@0k  
processErrorCode(responseCode); ~ A4_  
return -2; //-2 represent access is error H@BU/{  
} o :_'R5  
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[qQ~\]  
String sHeader; <wO8=bem  
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for(int i=1;;i++) !&@
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{ 4%,E;fB?=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~+bSD<!b  
//Utility.log(in.readLine()); FdMxw*}  
sHeader=httpConnection.getHeaderFieldKey(i); )L%[(iI,x  
if(sHeader!=null) 1bpjj'2%x  
{ wsyAq'%L  
if(sHeader.equals("Content-Length")) a29rD$  
{ TaE&8;H#N  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,5/zTLd   
break; mybvD  
} ^V;2v? O  
} }@avGt;v  
else Q:sw*7"F  
break; Qr$Ay3#k  
} \KT}T  
} 9ld'SB:#  
catch(IOException e){e.printStackTrace ();} */E5<DO  
catch(Exception e){e.printStackTrace ();} =U_O;NC  
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Utility.log(nFileLength); Pq)C(Z  
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return nFileLength; .m_-L Y-  
} |)IS[:X  
[SX>b"L  
KiO1l{.s8n  
//保存下载信息（文件指针位置） KL6FmL)HH  
private void write_nPos() 9|9Hk1  
{ 5p`.RWls  
try{ D_)n\(3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YQ#o3sjs  
output.writeInt(nStartPos.length); TEt+At`]  
for(int i=0;i<nStartPos.length;i++) Zh,{e/j  
{ |*-&x:p7O  
// output.writeLong(nPos); Kitx%P`i  
output.writeLong(fileSplitterFetch.nStartPos); #JIh-h@  
output.writeLong(fileSplitterFetch.nEndPos); Fi_JF;  
} ?5MOp  
output.close(); IW-lC{hK  
} +-+%6O<C  
catch(IOException e){e.printStackTrace ();} =&xNdc  
catch(Exception e){e.printStackTrace ();} #gd`X|<Ch  
} gdkQ h_\  
=TG[isC/F9  
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//读取保存的下载信息（文件指针位置） UgjY  
private void read_nPos() d1=fA%pJ  
{ tNbZ{=I>  
try{ v6q oH)n  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); z6f N)kw  
int nCount = input.readInt(); szW85{<+  
nStartPos = new long[nCount]; K|g+Wt^tQ  
nEndPos = new long[nCount]; fkmN?CU{1%  
for(int i=0;i<nStartPos.length;i++) 8s#2Zv  
{ i$:QOMA  
nStartPos = input.readLong(); M h5>@-fEE  
nEndPos = input.readLong(); A9L {c!|-  
} ofIw7D*h  
input.close(); RNB ha&  
} jizp\%W+  
catch(IOException e){e.printStackTrace ();} B+8B<xZ  
catch(Exception e){e.printStackTrace ();} SWrP0Qjc  
} mcFJ__3MAV  
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private void processErrorCode(int nErrorCode) B6gn(w3  
{ !w}cKm  
System.err.println("Error Code : " + nErrorCode); vRn
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} ^B`*4  
2J5RZg9jL  
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//停止文件下载 `rLy7\@;  
public void siteStop() -AcVVK&  
{ TaI72"8  
bStop = true; 8) 1+j>OQ  
for(int i=0;i<nStartPos.length;i++) xpjv@P  
fileSplitterFetch.splitterStop(); aHdXlmL  
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} s2rwFj8 |  
} wz{]CQ7"  
//负责部分文件的抓取 wW?/`>@  
**FileSplitterFetch.java r[}5<S Q  
*/ ,8^QV3  
package NetFox; ym~  
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import java.io.*; _cw~N p  
import java.net.*; oYn|>`+6:y  
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public class FileSplitterFetch extends Thread { [9U::  
0V_dg |.  

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String sURL; //File URL mOQN$d[  
long nStartPos; //File Snippet Start Position ?f\ ~:Gm/  
long nEndPos; //File Snippet End Position "q,.O5q}Y  
int nThreadID; //Thread's ID y(w&6:  
boolean bDownOver = false; //Downing is over Zj]jE%AT  
boolean bStop = false; //Stop identical :t8?!9g  
FileAccessI fileAccessI = null; //File Access interface ]6BV`r]  
^;@Q3~DpP%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DN%b!K
:  
{ pni*#W*n  
this.sURL = sURL; @W+m;4HH  
this.nStartPos = nStart; oFC]L1HN&  
this.nEndPos = nEnd; :,'yHVG\  
nThreadID = id; H;.${u^lhd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 n 9X:s?B/  
} ZP}NFh%,u  
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public void run() }mx>3G{d  
{ <bbC&O\  
while(nStartPos < nEndPos && !bStop) z +NwGVk3  
{ jf WZLb)  
b|'{f?  
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try{ 4[o/p8*/  
URL url = new URL(sURL); (SnrYO`#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kl0|
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httpConnection.setRequestProperty("User-Agent","NetFox"); 6myF!  H=  
String sProperty = "bytes="+nStartPos+"-"; (n+FEE<  
httpConnection.setRequestProperty("RANGE",sProperty); x$@Gp  
Utility.log(sProperty); ys~oJb~  
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:*6#(MX  
InputStream input = httpConnection.getInputStream(); ,u&K(Z%  
//logResponseHead(httpConnection); |Y")$pjz  
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6PyODW;R/5  
byte[] b = new byte[1024]; P1>?crw  
int nRead; bAVlL&^@|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b Y^K)0+^s  
{ (G<fvl!~  
nStartPos += fileAccessI.write(b,0,nRead); *@(j'0hj  
//if(nThreadID == 1) @?!&M c2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XQhbH^  
} abgAUg)  
X<*-d6?gD`  
L63B# H"  
Utility.log("Thread " + nThreadID + " is over!"); W~i599!v  
bDownOver = true; $ctpg9 7  
//nPos = fileAccessI.write (b,0,nRead); 1X,\:F.-+  
} 6Ex16  
catch(Exception e){e.printStackTrace ();} ,}jey72/k  
} IB%Hv]  
} ZtofDp5B  
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//打印回应的头信息 "
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public void logResponseHead(HttpURLConnection con) "eb+
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{ !bGMVw6_  
for(int i=1;;i++) 4u}jkd$]*  
{ H b}(.`  
String header=con.getHeaderFieldKey(i); T}r}uw`  
if(header!=null) z1vSt[s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); i~sW_f+  
Utility.log(header+" : "+con.getHeaderField(header)); 7~ =r9-&G  
else |J:kL3g  
break; WTX!)H6Zv  
} d"U'\ID2y  
} ! a!^'2  
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public void splitterStop() *\
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{
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bStop = true; 3U
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} (\o &Gl  
/4wPMAlb  
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} 3^-yw`  
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/* dR@XwEpP  
**FileAccess.java bb}$7v`G  
*//文件访问(定位，写) 7:$zSj#y  
package NetFox; &++tp5  
import java.io.*; <R.Ipyt.  
2}xvM"k=k  
t1rAS.z&  
public class FileAccessI implements Serializable{ t=BXuFiu  
:9Mqwgk,;3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -*AUCns#  
RandomAccessFile oSavedFile; }F=lG-x  
long nPos; uz'MUT(68  
\_|g}&}6Y  
*DS>#x@3*i  
public FileAccessI() throws IOException O&@pi-=o  
{ ay`A Gr  
this("",0); .0b4"0~T6  
} ? e<D +  
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''3b[<  
public FileAccessI(String sName,long nPos) throws IOException dk[MT'DV  
{ a
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oSavedFile = new RandomAccessFile(sName,"rw"); 6)j/"9oY  
this.nPos = nPos; .z}*!   
oSavedFile.seek(nPos); Uxb>)36I  
} W0;
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(_Ky'.  
1!p7N$QR  
public synchronized int write(byte[] b,int nStart,int nLen) 4KnrQ-D  
{ JS#AoPWA  
int n = -1; G/y;o3/[Z  
try{ E;-*LT&{  
oSavedFile.write(b,nStart,nLen); s^zX9IVnp  
n = nLen; /j$`Cq3I  
} 'd |*n#Dqc  
catch(IOException e) SEXmVFsQ
 
{ [iGL~RiXtn  
e.printStackTrace (); >))K%\p   
} 6#upBF:  
_]6n]koD,  
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return n;
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} >`o;hTS  
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} v)s; wD  
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/* wNQhg  
**SiteInfoBean.java 2e|m3  
*/ X3Yi|dyn T  
package NetFox; 'wd&O03&  
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public class SiteInfoBean { )=5
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private String sSiteURL; //Site's URL o%)38T*n3  
private String sFilePath; //Saved File's Path [/GCy0jk  
private String sFileName; //Saved File's Name n?}7vz;  
private int nSplitter; //Count of Splited Downloading File N"-U)d-.  
K6G+sBw[  
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public SiteInfoBean() m ^'!  
{//nSplitter的缺省值为5 B*&HQW *u  
//default value of nSplitter is 5 ihBIE  
this("","","",5); A?4s+A@Eg  
} 1;"DIsz@d  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &at>sQ'  
{ ]%eyrbU  
sSiteURL= sURL; %[WOQ.Sh  
sFilePath = sPath; Y0xn}:%K  
sFileName = sName; SI9PgC  
this.nSplitter = nSpiltter; ]CGH )4Pe  
[iUy_ C=qp  
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} Vl`!6.F3  
\kEC|O)8  
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public String getSSiteURL() )JXy>q#  
{ YES-,;ZQ'  
return sSiteURL; h42dk(B  
} ,lb >  
^2\-zX!bt  
,?(U4pzX  
public void setSSiteURL(String value) V|j{#;  
{
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sSiteURL = value; 4
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} q"Th\? }%  
 >B$J  
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public String getSFilePath() s}g3*_
"  
{ tf4clzSTa  
return sFilePath; ]:}x 4O#  
} O~4Q:#^c  
*yqke<o9)  
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public void setSFilePath(String value) 5Mz6/&`  
{ ZYs?65.  
sFilePath = value; <8YIQA  
} !P@4dG  
u]MQ(@HHF  
fir#5,*q|  
public String getSFileName() W-<`Vo'  
{ (o518fmR  
return sFileName; RW|Xh8.O  
} rbc7CPq_^  
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public void setSFileName(String value) yII+#?D  
{ (7w95xI  
sFileName = value; nQ08(8  
} N4$
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)*nZ6Cg'  
C"R}_C|r)*  
public int getNSplitter() EqF>=5*  
{ 3T~DeqAyw  
return nSplitter; ?yKG\tPhM  
} =k##*%  
{Lugdf'  
?eDZ-u9)  
public void setNSplitter(int nCount) &EJ/Rl
 
{ 79Ur1-]/  
nSplitter = nCount; 7}puj%JS /  
} tu6<>  
} <6.?:Jj  
4P}d/w?'KL  
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/* dZuPR  
**Utility.java ~WKWx.ul  
*/ }%`f%/  
package NetFox; V?"1&m&E  
TTD#ovo'  
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public class Utility { @YbZ"Jb  

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public Utility()  3 EOuJ  
{ FZtT2Z4&i  
L b-xc]  
5V8`-yO9  
} cp2a @  
*0x!C8*`Xe  
//线程睡眠 =5
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public static void sleep(int nSecond) 2hY"bpGW  
{ k_`YVsEYP  
try{ lw_@(E]E  
Thread.sleep(nSecond); aj]pN,g@N  
} A9y@v{tx
N  
catch(Exception e) ]sJjV A  
{ Uj^Y\w-@Z  
e.printStackTrace (); j+[
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} |}Mthj9n  
} ^+x,211f  
]-jaIvM  
//日志 Au"BDP  
public static void log(String sMsg) TGuCIc0B{  
{ t(1gJZs>kX  
System.err.println(sMsg); T'a&  
} `a5,5}7v%`  
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&'u%|A@  
public static void log(int sMsg) ';LsEI[  
{ zqxN/H]z  
System.err.println(sMsg); ?MOjtAG0_~  
} )i[K1$x2  
} F&HvSt}l5  
_mTNK^gB  
`2`h4[^ [X  
/* # blh9.V&F  
**TestMethod.java q+ka}@  
*/ T;v^BVn  
package NetFox; Se|h]+G  
|8fdhqy_  
HG^
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public class TestMethod { LBIEG_/m  
l $0w 9Z^  
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public TestMethod() s8SCEpz  
{ ///xx/weblogic60b2_win.exe 74
a k|(!  
try{ * yGlX
[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); WnhH]WY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !}q@O-}j  
SiteFileFetch fileFetch = new SiteFileFetch(bean); AmK g;9LS  
fileFetch.start(); k#G+<7c<  
} *~^%s+b  
catch(Exception e){e.printStackTrace ();} H[N~)3x  
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} KN~Repcz@  
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@%!Gj{
 
public static void main(String[] args) Y#FSU#a$<  
{ ([]\7}+8  
new TestMethod(); gB0Q0d3\G,  
} M7ug< 8i  
} [ZD`t,x(  
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