http断点续传简单实现（java)

/* 7HY8 F5Brx  
**SiteFileFetch.java ?b'(39fj  
*/ ;&f(7 Q+T_  
package NetFox; -5]lHw}  
import java.io.*; %.wR@
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import java.net.*; KHx;r@{<  
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public class SiteFileFetch extends Thread { Rq e|7/As  
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SiteInfoBean siteInfoBean = null; //文件信息Bean u|.|dv'mbp  
long[] nStartPos; //开始位置 ,)!%^~v  
long[] nEndPos; //结束位置 ntB#2S  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +4W
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long nFileLength; //文件长度 #H4<8B  
boolean bFirst = true; //是否第一次取文件 a5O$he  
boolean bStop = false; //停止标志 ]bmf}&  
File tmpFile; //文件下载的临时信息 f%1\1_^g  
DataOutputStream output; //输出到文件的输出流 7fzH(H  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） K
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public SiteFileFetch(SiteInfoBean bean) throws IOException ~;pP@DA  
{ ahZ@4v  
siteInfoBean = bean; lKU{jWA  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6vxRam6[??  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WlY\R>x#  
if(tmpFile.exists ()) n9 FA`e  
{ 7\$b%A  
bFirst = false; \K}KnJ  
read_nPos(); -|s%5p|  
} {~R?f$}""j  
else ])bgUH
 
{ #Tag"b`  
nStartPos = new long[bean.getNSplitter()]; $FIJI^Kd7  
nEndPos = new long[bean.getNSplitter()]; >Di`zw~  
}
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} ",[/pb  
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public void run() i$}G[v<4  
{ )+hJi/g  
//获得文件长度 _8-1wx  
//分割文件 Er8F_,M+  
//实例FileSplitterFetch q o-|.I  
//启动FileSplitterFetch线程 'qo(GGC M  
//等待子线程返回 Xt:j~cVA  
try{ <
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if(bFirst) $Jn.rX0}$  
{  xiQc\k$  
nFileLength = getFileSize(); "?<`]WG\  
if(nFileLength == -1) xO%yjG=  
{ >b#CR/^z  
System.err.println("File Length is not known!"); X}h}3+V  
} fpjFO&ML  
else if(nFileLength == -2) .wWf#bB  
{ 8@rF~^-_  
System.err.println("File is not access!"); .#a7?LUH  
} OI:=>Bk  
else 0$Zh4Y  
{ FEopNDy@y  
for(int i=0;i<nStartPos.length;i++) NU{eoqaT  
{ 0pB'^Q{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P@n rcgM.  
} 3BLHd<  
for(int i=0;i<nEndPos.length-1;i++) t4~?m{
 
{ 2v4&'C  
nEndPos = nStartPos[i+1]; BVH)!]m0  
} qX6zk0I a
 
nEndPos[nEndPos.length-1] = nFileLength; VC Ay~,  
} x 0vW9*&  
} i!JSEQ_8  
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//启动子线程 $(OL#>9Ly  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G%i&C)jZ  
for(int i=0;i<nStartPos.length;i++) ~"wnlG-:  
{ @^-f+o  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }095U(@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ov\%*z2=  
nStartPos,nEndPos,i); h]
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i1b3>H*3  
fileSplitterFetch.start(); ,y/
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} &@2`_%QtA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), **6X9ZIX[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :,/ \E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XC390t  
nEndPos = " + nFileLength); y|9 LtQ  
// fileSplitterFetch[nPos.length-1].start(); <3=k  
JE$$6X  
LA6Ik_-F  
//等待子线程结束 rXe+#`m2
 
//int count = 0; I3l1 _  
//是否结束while循环 bOV]!)o  
boolean breakWhile = false; Nii5},  
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while(!bStop) }y*rO(cu7G  
{ ?iaO6HD  
write_nPos(); Na.e1A&?j  
Utility.sleep(500); uIJ zz4  
breakWhile = true; &mA{_|>  
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[{ A5BE -  
for(int i=0;i<nStartPos.length;i++) IY2f$YV  
{ 5hAs/i9_  
if(!fileSplitterFetch.bDownOver) :ZM=P3QZ  
{ @Hp=xC9V  
breakWhile = false; +J}h  
break; wG22ffaki  
} oOQ0f |MGp  
} ]ddL'>$c$  
if(breakWhile) L'>0E(D  
break; 0J= $ A  
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//count++; k.H4Mf(4  
//if(count>4) C\cZ  
// siteStop(); 5Ak>/QF9  
} ]}_Ohe]X  
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System.err.println("文件下载结束！"); OnE~0+  
} |X~vsM0  
catch(Exception e){e.printStackTrace ();} 2QIo|$  
} VZA>ErB  
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//获得文件长度 .Na'yS `J  
public long getFileSize() 7bkh")^  
{ j2%#xZ{
33  
int nFileLength = -1; mi sPJO&QD  
try{ DJRr  
URL url = new URL(siteInfoBean.getSSiteURL()); #)KQ-x,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P?iQ{x}w~  
httpConnection.setRequestProperty("User-Agent","NetFox"); 93Qx+oK]  
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k,[[ CZ0j  
int responseCode=httpConnection.getResponseCode(); FWyfFCK  
if(responseCode>=400) #~qY%X  
{ 7)Bizlf  
processErrorCode(responseCode); I{u+=0^Y  
return -2; //-2 represent access is error o7:"Sl2AD  
} ^c>ROpic  
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String sHeader; :DBJ2n  
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for(int i=1;;i++) ]LSlo593  
{ 0 9*?'^s4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); mC`U"
rlK~  
//Utility.log(in.readLine()); y@]:7  
sHeader=httpConnection.getHeaderFieldKey(i); G\S_e7$/  
if(sHeader!=null) 4p`z%U~=u  
{ t-J\j"~%+  
if(sHeader.equals("Content-Length")) ]B
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{ 8d\/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Oj.xJ(uX+v  
break; TbhsOf!  
} t3aDDu  
} L>2gx$f  
else xO'xZ%cUI  
break; j|(bdTZY:  
} `[.4SIah  
} G%fNGQwT  
catch(IOException e){e.printStackTrace ();} Kdb:Q0B  
catch(Exception e){e.printStackTrace ();} ^g N?I
o  
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Utility.log(nFileLength); ltG|#(  
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return nFileLength; ?rububDT{  
} nA XWbavY  
\EeK<)4:  
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//保存下载信息（文件指针位置） ~C;gEE-  
private void write_nPos() 2lBfc  
{ Y>'t)PK  
try{ iJ~e8l0CA  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Zk 9i}H  
output.writeInt(nStartPos.length); x?-kt.M  
for(int i=0;i<nStartPos.length;i++) .&c!k1kH  
{ DP7B X^e  
// output.writeLong(nPos); Pt%Ey
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output.writeLong(fileSplitterFetch.nStartPos); BYsQu.N  
output.writeLong(fileSplitterFetch.nEndPos); 6SmawPPP  
} uze5u\  
output.close(); Je;HAhL  
} g2&P  
catch(IOException e){e.printStackTrace ();} CjlA"_!%E  
catch(Exception e){e.printStackTrace ();} *Mr'/qp,  
} 2o9IP>#u  
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//读取保存的下载信息（文件指针位置） bjGQ04da  
private void read_nPos() 1 gx(L*y,  
{ I r;Z+}4>Y  
try{ 7W\aX*]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +h?z7ZY^  
int nCount = input.readInt(); _f~m&="T!  
nStartPos = new long[nCount]; e.pq6D5  
nEndPos = new long[nCount]; sBm/9vu  
for(int i=0;i<nStartPos.length;i++) #_[W*-|L  
{ Ri
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nStartPos = input.readLong(); 8qQrJFm|3*  
nEndPos = input.readLong(); +%RB&:K7,  
} q|7$@H^*  
input.close(); O_/|Wx  
} ~l>2NY  
catch(IOException e){e.printStackTrace ();} ,*'aH z  
catch(Exception e){e.printStackTrace ();} SI@Yct]<g  
} 9q f=P3  
- -H%FYF`  
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private void processErrorCode(int nErrorCode) qz/d6-0"  
{ K yFR;.F-  
System.err.println("Error Code : " + nErrorCode); B< BS>(Nr>  
} 14;lB.$p  
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XP!7@:  
//停止文件下载 Pi:=0,"XOp  
public void siteStop() xSoXf0zq:  
{ `tZ`a  
bStop = true; 0ud>oh4WPR  
for(int i=0;i<nStartPos.length;i++) H@hHEzO  
fileSplitterFetch.splitterStop(); Qp]-4%^Vz  
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} #^oF^!  
} (qXl=e8  
//负责部分文件的抓取 eMV@er|  
**FileSplitterFetch.java 8|iMD1  
*/ sz+Uq]Mn  
package NetFox; P_3U4J  
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import java.io.*; )!(etB=`y  
import java.net.*; JqmKD4p  
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public class FileSplitterFetch extends Thread { 0ge^pO\Z  
-6u#:pVpU  
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String sURL; //File URL =
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long nStartPos; //File Snippet Start Position [e+$jsPl  
long nEndPos; //File Snippet End Position Pb-Ft=  
int nThreadID; //Thread's ID v<U +&D{  
boolean bDownOver = false; //Downing is over M~&X?/8  
boolean bStop = false; //Stop identical nzK"eNDN.  
FileAccessI fileAccessI = null; //File Access interface <<[hZ$.  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 86,$ I+  
{ -P3;7_}]:h  
this.sURL = sURL; ,dIo\Lm
 
this.nStartPos = nStart; "G`8>1tO_  
this.nEndPos = nEnd; .}l&lj
@#  
nThreadID = id; y3vm+tJc{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^9C9[$Q  
} {<3>^ o|"  
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public void run() kGX;x}q  
{ ]\t+zF>&Y  
while(nStartPos < nEndPos && !bStop) {Qla4U  
{ cWA$O*A  
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try{ c_r&)8  
URL url = new URL(sURL); /Aq):T T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2dF:;k k  
httpConnection.setRequestProperty("User-Agent","NetFox"); N%.DjH  
String sProperty = "bytes="+nStartPos+"-"; 5{&<X.jv  
httpConnection.setRequestProperty("RANGE",sProperty); TGJ\f  
Utility.log(sProperty); zsx12b^w  
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InputStream input = httpConnection.getInputStream(); br9`77J8  
//logResponseHead(httpConnection); aab?hR  
uF=xo`=|  
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byte[] b = new byte[1024]; %aszZP  
int nRead; k5@_
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dIR6dI   
{ #`0iN+qh
  
nStartPos += fileAccessI.write(b,0,nRead); 7o4 vf~  
//if(nThreadID == 1) rGe^$!QB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^{W#
ut>IN  
} :tA|g  
'0xJp|[xVP  
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Utility.log("Thread " + nThreadID + " is over!"); }bs2Rxkh  
bDownOver = true; cCjpQ  
//nPos = fileAccessI.write (b,0,nRead); A<&:-Zz  
} D?w-uR%Y  
catch(Exception e){e.printStackTrace ();} drQioH-  
} V!SB9t`E  
} (1vmtg.O  
CKTD27})  
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//打印回应的头信息 a'v%bL;H~  
public void logResponseHead(HttpURLConnection con) ):_x  
{ DvuL1MeKo  
for(int i=1;;i++) zq5_&AeW  
{ )^&)f!f  
String header=con.getHeaderFieldKey(i); B`4[@$  
if(header!=null) %-4e8d74/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); sKX%<n$  
Utility.log(header+" : "+con.getHeaderField(header)); S"=oU}'|  
else eXU;UO^  
break; DT=!  
} YJ5;a\QxN  
} ~%Ws"1  
uxto:6),P<  
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public void splitterStop() Xm`K@hJ@  
{ JHf}LZu  
bStop = true; C%P"Ds=w0N  
} hfvs'.  
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} NRKAEf_#w  
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/* omV.Qb'NS  
**FileAccess.java Dz&4za+{  
*//文件访问(定位，写) b)u9#%Q  
package NetFox; d]e`t"Aj  
import java.io.*;  <C4^Vem  
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public class FileAccessI implements Serializable{ na FZ<'t>&  
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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 utwh"E&W  
RandomAccessFile oSavedFile; <,0&Ox  
long nPos; tS2lex%  
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public FileAccessI() throws IOException -o#0Yt}3  
{ >?e*;f$VdJ  
this("",0); e_6 i896  
} |y%pP/;&!  
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public FileAccessI(String sName,long nPos) throws IOException /]xd[^  
{ j.CC.[$g  
oSavedFile = new RandomAccessFile(sName,"rw"); Yb =8\<;  
this.nPos = nPos; CSU>nIE0  
oSavedFile.seek(nPos); :B- ,*@EU  
} {uj9fE,)  
j)F~C8*  
%h%r6EB1F  
public synchronized int write(byte[] b,int nStart,int nLen) Ro:-u7q  
{ S0=BfkHi.  
int n = -1; XB;;
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try{ 73xI8  
oSavedFile.write(b,nStart,nLen); l}AB):<Z  
n = nLen; ^:-%tpB#!  
} Gz*U?R-T  
catch(IOException e) dm$:xE":  
{ kd\G>  
e.printStackTrace (); .yWdlq##  
} Fr%KO)s2  
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return n; 0/KNXz  
} &U 'Ds!  
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} <E\BKC%M  
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/* 2N,*S   
**SiteInfoBean.java 0\Oeo8<7)~  
*/ \+Cp<Hv+  
package NetFox; xDlC]loi7  
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public class SiteInfoBean { hcaH  
%)aDh }  
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private String sSiteURL; //Site's URL ^$#Q_Y|  
private String sFilePath; //Saved File's Path ac&tpvij  
private String sFileName; //Saved File's Name 2=3
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private int nSplitter; //Count of Splited Downloading File L:^'cl} G  
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public SiteInfoBean() z
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{//nSplitter的缺省值为5 sU}e78mh  
//default value of nSplitter is 5 \R#XSW,  
this("","","",5); q5RLIstQ\  
} etDB|(,z  
(8ymQ!aY  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -0\$JAyrx  
{ 7I.[1V`  
sSiteURL= sURL; yWK[@;S]%  
sFilePath = sPath; IaF79}^  
sFileName = sName; d~_OWCg`  
this.nSplitter = nSpiltter; l/I W"A  
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} FP\[7?ZLn  
?
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public String getSSiteURL() @LmUCP~  
{ QTyl=z7  
return sSiteURL;  :D/R  
} #e0+;kBh  
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public void setSSiteURL(String value) O0I/^  
{ ,#m\W8j  
sSiteURL = value; x-W0 h  
} C'$U1%: j  
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public String getSFilePath() lubS{3<  
{ 7)]G"m{  
return sFilePath; A
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} 4@Qq5kpk*  
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public void setSFilePath(String value) lwB!
ti  
{ s-DtkO  
sFilePath = value; l;C_A;y\  
} &S{F"z  
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public String getSFileName() U9q*zP_jV  
{ c
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return sFileName; 5u8Sxfm",  
} }qg!U
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public void setSFileName(String value) 0'<S7?~|  
{ S,v`rmI  
sFileName = value; B
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} WV% KoM,%  
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public int getNSplitter() Nf~<xK  
{ -Z@p   
return nSplitter; oa4}GNH  
} r5"/EMieh  
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public void setNSplitter(int nCount) N$+"zJmw&  
{ ;CrA  
nSplitter = nCount; A4^+p0@  
} 68SM br  
} `l}-S |a  
L9.#/%I\  
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/* f0F$*"#G  
**Utility.java F, "x~C  
*/ DjKjEZHgM  
package NetFox; Z*)<E)  
y\[=#g1(@  
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public class Utility { 2Ar<(v$  
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public Utility() A"'MRYT`  
{ { nV zN(  
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%L/=heBBd  
} (pmo[2kg  
6~}H
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//线程睡眠 EDo (  
public static void sleep(int nSecond) |h7v}Y  
{
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try{ |}`5<a!6U  
Thread.sleep(nSecond); (TE2t7ab|M  
} =T-w.}27O  
catch(Exception e) u!i5Q  
{ JvDsr0]\#  
e.printStackTrace (); WdT|xf.Q&  
} _(hwU>.  
} vf2K2\fn  
|(SW  
//日志 7'|PHQ?S  
public static void log(String sMsg) j#&  
{ >=V+X"\Z  
System.err.println(sMsg); ZwMw g t  
} <-F"&LI{<  
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public static void log(int sMsg) AV
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{ wL
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System.err.println(sMsg); H[D/Sz5`  
} ]c)SVn$6  
} BGX@n#:  
}]I?vyQ#V  
$<v_Vm?6d  
/* K288&D|1WU  
**TestMethod.java :~(im
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*/ !A!\S/x4  
package NetFox; R%%`wmG)"  
5)UmA8"zVB  
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public class TestMethod { K\b O[J  
+HX'AC  
+]-KzDsr"V  
public TestMethod() 9QMn%8=j  
{ ///xx/weblogic60b2_win.exe 2An`{')  
try{ Bt,Xe~$z-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R~~rqvLm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); o!~
bR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); to3J@:V8e  
fileFetch.start(); >|?T|  
} [R4x[36Zp  
catch(Exception e){e.printStackTrace ();} Wv"tAseu  
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} 5F"?]'
*/  
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public static void main(String[] args) ^>Y%L(>  
{ &r%*_pX  
new TestMethod(); ^{:jY, ?]  
} iIE(zw)H  
} <^U(ya  
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