http断点续传简单实现（java)

/* )v+R+3<  
**SiteFileFetch.java Z +vT76g3  
*/ ~@Wg3'&  
package NetFox; .C=I~Z  
import java.io.*; W|yFjE&dr  
import java.net.*; 68 *~5]  
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public class SiteFileFetch extends Thread { dP7nR1GS  
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+ bU*"5"  
SiteInfoBean siteInfoBean = null; //文件信息Bean {+SshT>J  
long[] nStartPos; //开始位置 b;K];o-/f  
long[] nEndPos; //结束位置 qIC9L"I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 WCpCWtmy  
long nFileLength; //文件长度 :=J^"c  
boolean bFirst = true; //是否第一次取文件 DJ
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boolean bStop = false; //停止标志 8=Z]?D=  
File tmpFile; //文件下载的临时信息 6M/*]jLq4  
DataOutputStream output; //输出到文件的输出流 UgBD|~zu  
@_L:W1[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） wyVQV8+&>  
public SiteFileFetch(SiteInfoBean bean) throws IOException RY4b<i3  
{ &W|r P(
 
siteInfoBean = bean; g:yUZ;U
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5x}XiMM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ))<1"7D^^  
if(tmpFile.exists ()) E;>BcP
t5  
{ O9_S"\8]@  
bFirst = false; \GFFPCi4D  
read_nPos(); Tx|}ke
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} -{=c T?"+  
else Z6F^p8O-  
{ WbP wO  
nStartPos = new long[bean.getNSplitter()]; .R<Ke\y/  
nEndPos = new long[bean.getNSplitter()]; R'Y=- yF  
} u[>hs \3k  
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} @TWtM#  
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public void run() nG+L'SmI  
{ wRATe 0'
 
//获得文件长度 $zR[2{bg  
//分割文件 pVGH)6P>|  
//实例FileSplitterFetch ER)<Twj  
//启动FileSplitterFetch线程 P_Bhec|#fT  
//等待子线程返回 ,]\:]Y&?  
try{
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if(bFirst) CQ( _$  
{ ?u)[xEx6}+  
nFileLength = getFileSize(); |*5QFp  
if(nFileLength == -1) }Efz+>F02  
{ -y+u0,=p.  
System.err.println("File Length is not known!"); >e4w8Svcy  
} >.fN@
8[  
else if(nFileLength == -2) sA}Xha  
{ uQYBq)p|  
System.err.println("File is not access!"); [|NgrU_.  
} +=qazE<:0  
else "\:ZH[j  
{ Y unY'xY  
for(int i=0;i<nStartPos.length;i++) ?#cX_  
{ rP=!!fC1;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #SR"Q`P  
} |}O9'fyU8  
for(int i=0;i<nEndPos.length-1;i++) $:aKb#l)  
{ dl%KD8  
nEndPos = nStartPos[i+1]; bns([F  
} R06zca  
nEndPos[nEndPos.length-1] = nFileLength; L+b"d3!G&%  
} &M6cCT]&M  
} y9>?  
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2S{IZ]  
//启动子线程 c[DC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ju@5D h  
for(int i=0;i<nStartPos.length;i++) G|"`kAa  
{ [p%OIqC`pB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oV7A"8L^a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >h+G$&8[y  
nStartPos,nEndPos,i); 02EbmP  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -A\J:2a|  
fileSplitterFetch.start(); +EnJyli  
} N;.cZp2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BWz7m9T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); L,QAE)S'a  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", KT5"/fv  
nEndPos = " + nFileLength); ?_NhR  
// fileSplitterFetch[nPos.length-1].start(); QCI-YJ&o  
qZ:--,9+  
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//等待子线程结束 z [qO5z~I  
//int count = 0; }k-rOi'jL  
//是否结束while循环 -i}@o1o\  
boolean breakWhile = false; b,7@)sZ*  
9=-!~_'1-  
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while(!bStop) |0wUOs*5  
{ <^Hh5kfS'  
write_nPos(); >#MGGCGL  
Utility.sleep(500); -/s2'  
breakWhile = true; L'>t:^QTh  
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for(int i=0;i<nStartPos.length;i++) /y\KLa  
{ !7:~"kk  
if(!fileSplitterFetch.bDownOver) pFu3FUO*;  
{ Xu1tN9:oE  
breakWhile = false; h.\9a3B:r  
break; x{B%TM-Ey  
} ">? y\#OA  
} nsq7,%5  
if(breakWhile) y?|JBf  
break; ={a8=E!;  
@'K+   
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//count++; 6^L4wd7)  
//if(count>4) L;},1 \  
// siteStop(); );$L#XpB  
} *(~=L%s  
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System.err.println("文件下载结束！"); A3UC=z<y  
} iG[an*#X  
catch(Exception e){e.printStackTrace ();} V0]6F  
} Ef;OrE""  
[-@Lbu-|  
F
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//获得文件长度 .<|7BHL  
public long getFileSize() +^c;4-X 0  
{ %h ?c  
int nFileLength = -1; j}=$2|}8{  
try{ kpkN GQ2  
URL url = new URL(siteInfoBean.getSSiteURL()); mn=G6h T}W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T[iwP~l  
httpConnection.setRequestProperty("User-Agent","NetFox"); 
& >AXB6  
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int responseCode=httpConnection.getResponseCode(); K"cN`Kj<*-  
if(responseCode>=400) .1yp
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{  \|Qx`-  
processErrorCode(responseCode); T j7
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return -2; //-2 represent access is error 5o~;0K]  
} Ksq{=q-T  
tZtyx;EP  
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String sHeader; 1)aB']K%  
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m
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for(int i=1;;i++) `N~;X~XFk  
{ npH2&6Yhi^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); uvK1gJrA)  
//Utility.log(in.readLine()); f$x\~y<[  
sHeader=httpConnection.getHeaderFieldKey(i); d#N<t`  
if(sHeader!=null) bBkF,`/f$  
{ fPs'A  
if(sHeader.equals("Content-Length")) "lo:"y(u  
{ ]@W.5!5H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Uk u~"OGC  
break; @<ba+z>"~4  
} `e t0i.  
} P9/5M4]tt  
else -<gGNj.x-  
break; |0?h6  
} Y~T;{&wi  
} ;Cdrjx  
catch(IOException e){e.printStackTrace ();} slV+2b  
catch(Exception e){e.printStackTrace ();} n"dC]&G'  
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Utility.log(nFileLength); -{i;!XE$SR  
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return nFileLength; C>q,c3s5  
} V:rq}F}  
**V^8'W<  
/jQW4eW0  
//保存下载信息（文件指针位置） ZqQJFyV*  
private void write_nPos() I| qoHN,g  
{ /wB<1b"  
try{ )+c4n]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); uI7 d?s  
output.writeInt(nStartPos.length); !HM|~G7  
for(int i=0;i<nStartPos.length;i++) CPVR  
{ 48CLnyYiF  
// output.writeLong(nPos); H/>86GG  
output.writeLong(fileSplitterFetch.nStartPos); oagxTFh8~  
output.writeLong(fileSplitterFetch.nEndPos); q/Dc*Qn m  
} <@9p|[!  
output.close(); +(iM]L$Fw%  
} 12*'rU;*  
catch(IOException e){e.printStackTrace ();} AvdxDN  
catch(Exception e){e.printStackTrace ();} iN0gvjZ  
} ]Cpd`}'  
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//读取保存的下载信息（文件指针位置） A.<HOx&#  
private void read_nPos() &k+G^ !=s#  
{ {O,D9
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try{ pOlo_na}[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~9JU_R^%m  
int nCount = input.readInt(); 6D,xs}j1  
nStartPos = new long[nCount]; UH1AT#?!W  
nEndPos = new long[nCount]; @~0kSA7  
for(int i=0;i<nStartPos.length;i++) 9"g=it2Rh6  
{ ,vEwck#  
nStartPos = input.readLong(); .7TQ
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nEndPos = input.readLong(); > $0eRVL  
} "ZDc$v:Qa  
input.close(); N.OC _H&  
} wkK61ah6  
catch(IOException e){e.printStackTrace ();} 0[@9f1Nk4  
catch(Exception e){e.printStackTrace ();} sw{,l"]<  
} 8;YeEW5  
)&}\2NK6L  
$}0q=Lg%wv  
private void processErrorCode(int nErrorCode) 0S <;T+WA  
{ /T`L;YE  
System.err.println("Error Code : " + nErrorCode); "Zd4e2>{M\  
} B#'TF?HUEn  
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//停止文件下载 1\:puC\)  
public void siteStop() R{.5Z/Vp6E  
{ Fx2z lM&  
bStop = true; >VnkgY  
for(int i=0;i<nStartPos.length;i++) "h'0&ZP~_  
fileSplitterFetch.splitterStop(); $F-qqkR$  
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} Q#8}p
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} 7Wb:^.d g  
//负责部分文件的抓取 ,Ju

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**FileSplitterFetch.java qepsR/0M  
*/ r+fR^hv  
package NetFox; =D.M}xqo  
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import java.io.*; ^& ZlV  
import java.net.*; ab8uY.j  
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public class FileSplitterFetch extends Thread { y#
8| @?  
6>ZUx}vYj  
9\RSJGx6  
String sURL; //File URL X96>N{C*>  
long nStartPos; //File Snippet Start Position es@_6ol.@  
long nEndPos; //File Snippet End Position 6r/NdI  
int nThreadID; //Thread's ID }Z*@EWc>  
boolean bDownOver = false; //Downing is over PLR[nB7K  
boolean bStop = false; //Stop identical E+Z//)1Z  
FileAccessI fileAccessI = null; //File Access interface v# ab2  
i8pM,Ppi~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4jefU}e9#  
{ ZKTOif}  
this.sURL = sURL; UA$ XjP  
this.nStartPos = nStart; n5dFp%k  
this.nEndPos = nEnd; O,6Upk  
nThreadID = id; Q':xi;?Kt  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2C^/;z  
} laN:H mR8  
7UvfXzDNC  
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public void run() <CIJ
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{ mw)KyU#l,:  
while(nStartPos < nEndPos && !bStop) F2!C^r,~L  
{ p@]\N  
v 0mc1g+9  
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try{ d)F~)}TFM  
URL url = new URL(sURL); & .VciSq6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8<ZxE(v  
httpConnection.setRequestProperty("User-Agent","NetFox"); =!m5'$Uz>  
String sProperty = "bytes="+nStartPos+"-"; 57IAH$n8o  
httpConnection.setRequestProperty("RANGE",sProperty); ^c3~CD5H 3  
Utility.log(sProperty); 6KPM4#61o  
:5hKE(3Q  
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InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection); ?WE#%W7U  

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byte[] b = new byte[1024]; IMLk{y%6  
int nRead; O\;Z4qn2=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R{GOlxKs C  
{ ^6s<  
nStartPos += fileAccessI.write(b,0,nRead);
a5jc8S>  
//if(nThreadID == 1) NXsDn&&O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3jQy"9f  
} 4eTfb  

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Utility.log("Thread " + nThreadID + " is over!"); >2tQ')%DJ  
bDownOver = true; '"&M4.J{  
//nPos = fileAccessI.write (b,0,nRead); ]s-;*o\H  
} x? 3U3\W  
catch(Exception e){e.printStackTrace ();} W1S7%6y_1  
} 8P5yaS_  
} [sJ f)<  
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'<_nL8A^  
//打印回应的头信息 `%}SK~<R  
public void logResponseHead(HttpURLConnection con) i356m9j  
{ K|nh`r   
for(int i=1;;i++) =TKu2  
{ yq+'O&+   
String header=con.getHeaderFieldKey(i); b
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if(header!=null) 0zfh:O  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ek!x:G$'  
Utility.log(header+" : "+con.getHeaderField(header)); N9hs<b+N_  
else Z18T<e  
break; nNJU@<|{*  
} ?g gl8bzA  
} GlkTpX^b  
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o?(({HH
 
public void splitterStop() x01n  
{ (os}s8cIh  
bStop = true; d-Vttxa6  
} AsJN~<0h  
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} E~vM$$O$  
3V~871:-~  
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/* o1C1F}gxU  
**FileAccess.java ZXV_Dc
 
*//文件访问(定位，写) .l?sYe64S  
package NetFox; C+ar]Vi
 
import java.io.*; C(-wA  
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public class FileAccessI implements Serializable{ x=>B 6o-f  
qv\n]M_&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2F*spu  
RandomAccessFile oSavedFile; 278:5yC  
long nPos; kN(*.Q|VZ  
4/UY*Us&  
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public FileAccessI() throws IOException (;DnL|"'8  
{ w#|uR^~  
this("",0); }ie O  
} `{w.OK  
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public FileAccessI(String sName,long nPos) throws IOException {l$DNnS  
{ /)RyRS8c  
oSavedFile = new RandomAccessFile(sName,"rw"); ILi{5L  
this.nPos = nPos; ,z<J`n  
oSavedFile.seek(nPos); E4;vC ?K{  
} SFhi]48&V
 
|@'/F#T  
 I/YBL  
public synchronized int write(byte[] b,int nStart,int nLen) 8@;|x2=y  
{ k1Z"Qmz  
int n = -1; f_A'.oq+  
try{ +tOmKY  
oSavedFile.write(b,nStart,nLen); j9Qd 45  
n = nLen; `
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} 7#/->Y  
catch(IOException e) a#3+PB#  
{ 6ub-NtVu  
e.printStackTrace (); L#U-dzy\  
} UuXq+HYR  
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=' %r"_`}  
return n; 0 D^d-R,  
} +xoh=m  
Z;M}.'BE  
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} ."`mh&+`  
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/* 9$ GAs  
**SiteInfoBean.java as#_Fer`U  
*/ O7<--  
package NetFox;
vG E;PwR  
r 0mA  
m~7[fgN2  
public class SiteInfoBean { MU_8bK9m  
)?_x$GKY  
`D *U@iJ  
private String sSiteURL; //Site's URL _8zZ.~)  
private String sFilePath; //Saved File's Path T}fH  
private String sFileName; //Saved File's Name Nf@-i`  
private int nSplitter; //Count of Splited Downloading File dKk\"6 o  
*=G~26*!V  
~>2DA$Ec  
public SiteInfoBean() ? 2#tIND  
{//nSplitter的缺省值为5 X8(H#Ef[  
//default value of nSplitter is 5 aTi2=HL=S  
this("","","",5); kdmmfw  
} :Q\Es:y  
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v67utISNI  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @:2<cn`  
{ op!ft/Yyb  
sSiteURL= sURL; *=yUs'brB  
sFilePath = sPath; F7o#KN*.]  
sFileName = sName; 1#nR$  
this.nSplitter = nSpiltter; o 8fB  
pTzwyj!SD  
+=_^4  
} W^(:\IvV  
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.>X0 $#  
public String getSSiteURL() @^q|C&j  
{ 
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return sSiteURL; YgiLfz iT  
} &\n<pXQ  
tr[(,kX  
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public void setSSiteURL(String value) .~3s~y*s  
{ ,Z3 (`ftC  
sSiteURL = value; ;JpsRf!  
} >JSk/]"  
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public String getSFilePath() 2YW|/o4  
{ s)dL^lj;  
return sFilePath;  !' }  
} b\Wlpb=QZ  
j<*  
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public void setSFilePath(String value) O {hM  
{ S*aMUV&  
sFilePath = value; \r.{Ru  
} 0fOx&"UAB  
Q4H(JD1f)  
h4iz(*  
public String getSFileName() g$^:2MT"aQ  
{ ~8oti4  
return sFileName; Sa8KCWgWh  
} U{`Q_Uw@$:  
7%MD0qm-  

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public void setSFileName(String value) MbT;]Bo  
{ p1BMQ?=($  
sFileName = value; MBIlt 1P  
} tf
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public int getNSplitter() SlaHhq3  
{ pYRqV  
return nSplitter; `d,v  
} -22
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eb#yCDIC  
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public void setNSplitter(int nCount) nO\c4#ce  
{ 6x.ZS'y  
nSplitter = nCount; e=H,|)P  
} 8h?):e  
} ~dtS  
HL`=zB%  
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/* If*+yr|  
**Utility.java @H83Ad  
*/ bb4
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package NetFox;  %"jp':  
2 -C*RHRx  
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public class Utility { w7d<Ky
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! ^ DQX=1  
public Utility() \3hj/   
{ rYKGBo8"  
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}  ob_*fP  
1;E^3j$  
//线程睡眠 c e\|eN[  
public static void sleep(int nSecond) L,/(^0;  
{ [6u8EP0xM  
try{ 'JpCS  
Thread.sleep(nSecond); E9bc pup  
} e[($rsx  
catch(Exception e) *NjjFk=R  
{ CG0jZB#u  
e.printStackTrace (); `zP{E T_Y  
} W1!Nq`  
} j*fs [4  
|y%M";MI  
//日志 [-p?gyl  
public static void log(String sMsg) Z(|'zAb^  
{ IQ]tcSQl  
System.err.println(sMsg); sy(8-zbI  
} !uc"|S?  
K\VL[HP-  
?l/+*/AR;  
public static void log(int sMsg) (/[wM>q:r  
{ AdL>?SG%  
System.err.println(sMsg); 4Q?3gA1  
} ?.~hex#M@  
} V"u .u  
,3,(/%=k  
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/* LDgGVl  
**TestMethod.java Oh'C[  
*/ 6V&HlJH  
package NetFox; c?t,,\o(}  
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+#RqQ8\  
public class TestMethod { K)&oDwk  
L3J .Oh  
YcdT/
  
public TestMethod() }1BpIqee  
{ ///xx/weblogic60b2_win.exe 2PDU(R  
try{ ~a06x^=j  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YsA.,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); G9AQIU%ii  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M@a=|N~  
fileFetch.start(); x&d:V  
} &fRZaq'2R  
catch(Exception e){e.printStackTrace ();} =8W'4MC  
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@UwDsx&2(t  
} p->b Vt  
+'ADN!(B_  
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public static void main(String[] args) 9>!B .Z?!#  
{ )+dd  
new TestMethod(); *R_mvJlT  
} ,1ceNF#o
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} @E !`:/k
 
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