http断点续传简单实现（java)

/* p54e'Zb  
**SiteFileFetch.java 4OOI$J$Jh  
*/ .k
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package NetFox; q~. .Z Y`7  
import java.io.*; ,8[R0wsBaz  
import java.net.*; \ lW*.<  
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public class SiteFileFetch extends Thread { lk
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SiteInfoBean siteInfoBean = null; //文件信息Bean Ju-#F@38  
long[] nStartPos; //开始位置 b Bkg/p]  
long[] nEndPos; //结束位置 n,#o6ali>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]u|5ZCv0  
long nFileLength; //文件长度 s:xt4<  
boolean bFirst = true; //是否第一次取文件 nTv^][
 
boolean bStop = false; //停止标志 &8HJ4Vj2  
File tmpFile; //文件下载的临时信息 +8}8b_bgH  
DataOutputStream output; //输出到文件的输出流 8}aS
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \2Yo*jE}  
public SiteFileFetch(SiteInfoBean bean) throws IOException a|-B#S  
{ V~7Oa2'#B  
siteInfoBean = bean; wBCBZs$H  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^tL]QE?|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); MjW{JR)I  
if(tmpFile.exists ()) 0`4Fa^o]h  
{ =zW`+++3  
bFirst = false; @NYlVk2  
read_nPos(); .h-k*F0Ga)  
} goZw![4l  
else >p29|TFbV  
{ 04c`7[  
nStartPos = new long[bean.getNSplitter()]; TBmmC}PEd  
nEndPos = new long[bean.getNSplitter()]; :gM_v?sy  
} ts&sr  
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} OzV|z/R2'  
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public void run() _N"c,P0  
{ f
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//获得文件长度 _|>bOI  
//分割文件 i\zN1T_  
//实例FileSplitterFetch MZt&HbD-  
//启动FileSplitterFetch线程 a?X#G/)  
//等待子线程返回 :0% $u>;O:  
try{ )U+&XjK  
if(bFirst) :+<GJj_d+  
{ Ai~d  
nFileLength = getFileSize(); e@DVf  
if(nFileLength == -1) a/Cc.s   
{ 7 V=%&+  
System.err.println("File Length is not known!"); ,#.9^J  
} m^;A]
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else if(nFileLength == -2) D26A%[^O  
{ T#3`&[  
System.err.println("File is not access!"); `;
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} s;,ulME  
else YH3[Jvzf4  
{ 9u1Fk'cxG,  
for(int i=0;i<nStartPos.length;i++) yHmNO*(  
{ ]4[^S.T=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #{~3bgY  
} gcF V$  
for(int i=0;i<nEndPos.length-1;i++) ;m}o$`  
{ Lu[xoQ~I  
nEndPos = nStartPos[i+1]; lj %k/u  
} ?mh0^G  
nEndPos[nEndPos.length-1] = nFileLength; M5{vYk>,1Q  
} +IM6 GeH  
} XBos^Q  
71G00@&w9D  
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//启动子线程 0E`6g6xMS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &Ui&2EW  
for(int i=0;i<nStartPos.length;i++) e ls&_BPE  
{ 9=G dj!L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *cc|(EM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3&
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nStartPos,nEndPos,i); :i]g+</  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cgn@@P5ZC  
fileSplitterFetch.start(); oI9-jW  
} u\@L|rh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), QW>(LGG=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); h
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [zhcb+^5l  
nEndPos = " + nFileLength); O;RNmiVoq  
// fileSplitterFetch[nPos.length-1].start(); ;Rd\yAG  
6gD|QC~;  
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//等待子线程结束 {ud^+I&  
//int count = 0; $F~hL?"?  
//是否结束while循环 Ffr6P }I  
boolean breakWhile = false; (=w ff5U  
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p ;){JT  
while(!bStop) fZt3cE\  
{ &:Sb$+z  
write_nPos(); K9Bi2/N  
Utility.sleep(500); #*;Nb  
breakWhile = true; /[Sy;wn  
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for(int i=0;i<nStartPos.length;i++) 'q*:+|"  
{ E']Gh  
if(!fileSplitterFetch.bDownOver) Wg5i#6y8w  
{ et :v4^*f  
breakWhile = false; 6T=zHFf~  
break; }NETiJ"6  
} 8A|i$#.&  
} 2s8(r8AI  
if(breakWhile) 0%5x&vx'S  
break; z,/y2H2  
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gb@ |\n  
//count++; My\  
//if(count>4)
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// siteStop(); >jBnNA@  
} o!M*cyq  
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System.err.println("文件下载结束！"); &<%U7?{~  
} w\3'wD!  
catch(Exception e){e.printStackTrace ();} 7`6JK  
} Id'@!U:NA  
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//获得文件长度 [8C6%n{W  
public long getFileSize()
&-6D'@  
{ k0R;1lZ0n  
int nFileLength = -1; |A@Gch fd  
try{ =v]
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URL url = new URL(siteInfoBean.getSSiteURL()); 3a#
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9@|X~z5E  
httpConnection.setRequestProperty("User-Agent","NetFox"); b3!,r\9V  
9 ulr6  
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int responseCode=httpConnection.getResponseCode(); _G5MQ%z  
if(responseCode>=400) yy-\$<j  
{ zVs|go>F  
processErrorCode(responseCode); aXefi'!6  
return -2; //-2 represent access is error ~+Da`Wp  
} wuTCdBu6hU  
"RJf2~(ZX  
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String sHeader; xj!_]XJ^w  
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for(int i=1;;i++) R!.HS0i.  
{ c~UYs\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }qOC*k:  
//Utility.log(in.readLine()); $0K%H  
sHeader=httpConnection.getHeaderFieldKey(i); o$r]Z
1  
if(sHeader!=null) 1f1J'du  
{ <U$A_]*w  
if(sHeader.equals("Content-Length")) #Rdq^TGMi;  
{ weiqt *,8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /< CjBW:
 
break; q>q@ztt  
} 
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} 6'6@VB  
else >AW=N  
break; '2%/h4jY  
} =}~hbPJM  
} KCed!O
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catch(IOException e){e.printStackTrace ();} S,,3h0$X  
catch(Exception e){e.printStackTrace ();} 3f:I<S7  
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Utility.log(nFileLength); YA>du=6y\  
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return nFileLength; <`q|6XWL  
} (&$|R\W.  
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M
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//保存下载信息（文件指针位置） Yn}_"FO'  
private void write_nPos() |8"~ou:.  
{ -$4%@Z  
try{ VBssn]w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3EcmNwr
 
output.writeInt(nStartPos.length); <z|?C  
for(int i=0;i<nStartPos.length;i++)
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{ EhybaRy;C  
// output.writeLong(nPos); q'?:{k$%  
output.writeLong(fileSplitterFetch.nStartPos); hqY9\,.C  
output.writeLong(fileSplitterFetch.nEndPos); $
{ ~UA6  
} MNiu5-g5  
output.close(); p\8
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} (;a O%  
catch(IOException e){e.printStackTrace ();} J7.bFW'  
catch(Exception e){e.printStackTrace ();} 1h+!<c q  
} GfU+'k;9  
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//读取保存的下载信息（文件指针位置） @"HR"@pX  
private void read_nPos() @:xO5L}Io  
{ \wNn c"  
try{ Y(SgfWeK@1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7`tnoTUv  
int nCount = input.readInt(); _A)<"z0E  
nStartPos = new long[nCount]; XI\aZ\v  
nEndPos = new long[nCount]; Rhx7eU#&  
for(int i=0;i<nStartPos.length;i++) UUY-EC7X  
{ k&DHQvfB  
nStartPos = input.readLong(); Ik1,?A
 
nEndPos = input.readLong(); h{sW$WA  
} -&kQlr  
input.close(); KF'H|)!K  
} fu=}E5ScK  
catch(IOException e){e.printStackTrace ();} tTyu,%/m  
catch(Exception e){e.printStackTrace ();} %MP s}B  
} #Y}Hh7.<  
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private void processErrorCode(int nErrorCode) ;.W0Aa  
{ {zUc*9  
System.err.println("Error Code : " + nErrorCode); "\BP+AF  
} Whd4-pR8  
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//停止文件下载 ^^?DYC   
public void siteStop() 2ZtqZ64i  
{ 9zO3KT2  
bStop = true; D-3/?"n  
for(int i=0;i<nStartPos.length;i++) L238l  
fileSplitterFetch.splitterStop(); 54J<ZXCs  
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} 9'toj%XQ  
} kFM'?L&  
//负责部分文件的抓取 {|xwvTlJ  
**FileSplitterFetch.java G>mgoN  
*/  A]U]  
package NetFox; 0dkM72p  
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import java.io.*; 4!k={Pd  
import java.net.*; fe37T@  
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public class FileSplitterFetch extends Thread { #]eXI $HP  
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}7=a,1T  
String sURL; //File URL  29sgi"  
long nStartPos; //File Snippet Start Position 0!vC0T[  
long nEndPos; //File Snippet End Position xk|$Oa  
int nThreadID; //Thread's ID \;7DS:d@  
boolean bDownOver = false; //Downing is over FOk @W&  
boolean bStop = false; //Stop identical M+hc,;6  
FileAccessI fileAccessI = null; //File Access interface jq0tMTb%L  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M@'V4oUz  
{ (C-z8R Z6  
this.sURL = sURL; WQ5sC[&   
this.nStartPos = nStart; ^Nsl5  
this.nEndPos = nEnd; @5?T]V g  
nThreadID = id; i9!Urq-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H;sQ]:.*]  
} 4G>|It  
=(n'#mV  
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public void run() 3yKI2en"  
{ AVyZ#`,  
while(nStartPos < nEndPos && !bStop) ax^${s|{-  
{ /a$+EQ$  
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try{ .897Z|$VB  
URL url = new URL(sURL); 2 !;4mij,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g Go  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0[1!K&(L  
String sProperty = "bytes="+nStartPos+"-"; d(@A  
httpConnection.setRequestProperty("RANGE",sProperty); m@O\Bi}=}  
Utility.log(sProperty); 9>i6oF]Oq  
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InputStream input = httpConnection.getInputStream(); <Y#R]gf1  
//logResponseHead(httpConnection); !GIsmqVY  
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byte[] b = new byte[1024]; yX-xVvlv@  
int nRead; 8zc!g|5"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) + kF[Oh#  
{ P+b^;+\1s  
nStartPos += fileAccessI.write(b,0,nRead); %b{!9-n}  
//if(nThreadID == 1) ^ Wl/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c}QJ-I  
} aqM_t  
Q jBCkx]g  
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Utility.log("Thread " + nThreadID + " is over!"); vLS9V/o  
bDownOver = true; !X8UP{J)L  
//nPos = fileAccessI.write (b,0,nRead); o(``7A@7a  
} RE.@ +A  
catch(Exception e){e.printStackTrace ();} 9/$P_Q:3  
} zOE6;c81  
} {6n \532@  
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) ,hj7  
//打印回应的头信息 \Zv =?\  
public void logResponseHead(HttpURLConnection con) dI!/:x  
{ btF%}<o)  
for(int i=1;;i++) _Y|kX2l S@  
{ cik@QN<[0
 
String header=con.getHeaderFieldKey(i); V[I<9xaE  
if(header!=null) -$)Et|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V`M,d~:Pr"  
Utility.log(header+" : "+con.getHeaderField(header)); ,xz^k/.  
else 68c;V
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break; yy
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} |d5L Ifb(  
} 2`I;f/Sd  
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public void splitterStop() e\_6/j7'  
{ BP[U` !  
bStop = true; .V3Dql@z"  
} l1)pr{A  
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} :b;1P@W<  
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/* 8@aS9th$  
**FileAccess.java #5C3S3e=  
*//文件访问(定位，写) O|RO j  
package NetFox;
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import java.io.*; #(IMRdUf  
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public class FileAccessI implements Serializable{ a1`cI5
n  
"
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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 tTFoS[V  
RandomAccessFile oSavedFile; 93Gur(j^  
long nPos; 3K!0 4\  
|2<f<k/UT  
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public FileAccessI() throws IOException %gMpV  
{ W-PZE|<  
this("",0); -NPkN%h  
} (bt]GAxb1  
'h^DI`  
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public FileAccessI(String sName,long nPos) throws IOException gyQ9Z}  
{ =(X'c.%i  
oSavedFile = new RandomAccessFile(sName,"rw"); LXC`Zq\  
this.nPos = nPos; e-cb?.WU?  
oSavedFile.seek(nPos); G^ZkY  
} &8AS=v  
>
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public synchronized int write(byte[] b,int nStart,int nLen)  |~uzQU7  
{ A]?O&m|  
int n = -1; c;rp@_ULG?  
try{ U\8#Qvghf  
oSavedFile.write(b,nStart,nLen); h==GdS4  
n = nLen; 8}oDRN!
J  
} f5GR#3-h(  
catch(IOException e) x0A%kp&w  
{ cNr][AzU@  
e.printStackTrace (); :_\!t45  
} ?SOF n  
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return n; q3-;}+  
} D'[P,v;Q  
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} inv{dg/2  
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/* Vc52s+7=8  
**SiteInfoBean.java b)hOz
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*/ 3zA=q[C  
package NetFox; y]pN=<*h5  
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public class SiteInfoBean { `?o1cf A  
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private String sSiteURL; //Site's URL ~sHZh  
private String sFilePath; //Saved File's Path &]yJCzo]  
private String sFileName; //Saved File's Name Y5i`pY/}#?  
private int nSplitter; //Count of Splited Downloading File G2+)R^FSC  
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public SiteInfoBean() ioY\8i  
{//nSplitter的缺省值为5 d!QD vO  
//default value of nSplitter is 5 BQuliX&  
this("","","",5); zj$_iB`9  
} =Sb:<q+Q  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -6~dJTm[t  
{ 1|EU5<  
sSiteURL= sURL; p-yOiG8b}  
sFilePath = sPath; a,57`Ks+n<  
sFileName = sName; >,"D9!  
this.nSplitter = nSpiltter; &Rl3y\ r  
[5p7@6:$u  
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} ^8-~@01.`_  
\,%o>M'  
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public String getSSiteURL() ;c m wh<  
{ spU!t-n67  
return sSiteURL; J'\eS./w|  
} %I|+_ z&x  
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public void setSSiteURL(String value) q:-]d0B+  
{ IGK_1@tq  
sSiteURL = value; Y0L5W;iM  
}
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1Oca@E\Z.  
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public String getSFilePath() & GzhcW~
 
{ @RoRNat  
return sFilePath; _Xk03\n6  
} L VU)W^  
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public void setSFilePath(String value) J+cAS/MYX  
{ SZK
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sFilePath = value; 4gv.E 0Fo  
} yYG3/Z3
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public String getSFileName() EBIa%,  
{ ~D-JZx  
return sFileName; fNAo$O4cm  
} 0[2BY]`Z.  
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public void setSFileName(String value) G>[ NZE  
{ qr'x0r|<>  
sFileName = value; \
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} s#
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hs{&G^!jo  
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public int getNSplitter() (?!(0Ywbg  
{ qlz9&w  
return nSplitter; ;e~{
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} Ere?d~8  
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public void setNSplitter(int nCount) Y0Hq+7x  
{ +#-kIaU  
nSplitter = nCount; ^&`
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} Mz/]DJ8  
} +gbX}jF0%  
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3WO#^}t  
/* t?]\M&i&  
**Utility.java (^DLCP#*  
*/ "}'8`k+d  
package NetFox; F_Z&-+,*3t  
`N|U"s;  
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public class Utility { ih+*T1#:(  
IFd )OZ5  
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public Utility()  !fQJL   
{ "<PoJPh  
[):{5hMA  
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} 5"-una>D  
9*}i
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//线程睡眠 &\J?[>EJ.  
public static void sleep(int nSecond) e5qrQwU  
{ ill-%OPeg  
try{ {h
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Thread.sleep(nSecond); %XEKhy  
} 0On?{Bw  
catch(Exception e) !G)mjvEe  
{ /~o7Q$)-b  
e.printStackTrace (); `y8 ?=  
} 8 3z'#  
} :X'*8,]KHH  
z+3<$Z  
//日志 LJRg>8  
public static void log(String sMsg) ZNzR`6}  
{ _'!aj+{  
System.err.println(sMsg); 1s{ISWm  
} u @{E{  
pY+.SuM  
d\~p5_5.  
public static void log(int sMsg) L.C ^E7;Z_  
{ z
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System.err.println(sMsg); (v|r'B9b  
} BA~a?"HS  
} T"L0Iy!k;  
Ys"|</;dbj  
,vY)n6  
/* B<|:K\MA  
**TestMethod.java .ocx(_3G  
*/ Zu\p;!e  
package NetFox; Q0pC4WJ`  
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w{k1Y+1  
public class TestMethod { 1a7!4)\  
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public TestMethod() I#"t'=9H  
{ ///xx/weblogic60b2_win.exe L8K0^~Mk  
try{ 4`'8fe/"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [8,PO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O0@w(L-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6eOrs-ty  
fileFetch.start(); Ze-MAt  
} NJn&>/vM  
catch(Exception e){e.printStackTrace ();} aQ(`6DQv  
Z} c'Bm(  
iLF^%!:X%  
}  uY.=4l  
v#RW{kI  
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public static void main(String[] args) /SnynZ.q  
{ mgy"|\]  
new TestMethod(); {F'Az1^I=  
} T#\p%w9d  
} (7IqY1W  
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