http断点续传简单实现（java)

/* P0@,fd<  
**SiteFileFetch.java DQ3<$0  
*/ 8LKiS  
package NetFox; 8tL~FiHb"  
import java.io.*; N7"W{"3D  
import java.net.*; L0,'m
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public class SiteFileFetch extends Thread { b}`TLn  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7.Op<  
long[] nStartPos; //开始位置 ?9/G[[(  
long[] nEndPos; //结束位置 sRs>"
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 dV_G1'  
long nFileLength; //文件长度 i5Ggf"![  
boolean bFirst = true; //是否第一次取文件 23PGq%R  
boolean bStop = false; //停止标志 =cI(d ,  
File tmpFile; //文件下载的临时信息 "jZ-,P=  
DataOutputStream output; //输出到文件的输出流 .#gzP2 [q  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） o-5TC  
public SiteFileFetch(SiteInfoBean bean) throws IOException !L(^(;$Kgr  
{ Cdn J&N{  
siteInfoBean = bean; TjH][bH5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y2AJ+ |  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pBH
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if(tmpFile.exists ()) tQ)qCk07  
{ ZK,G v  
bFirst = false; 6P3*Z  
read_nPos(); 4?kcv59  
} (.:e,l{U%  
else ah"o~Cbj  
{ >MZ/|`[M  
nStartPos = new long[bean.getNSplitter()]; h p1Bi  
nEndPos = new long[bean.getNSplitter()]; 7Q 3k7  
} Txu/{M,  
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{ 6il`>=C  
} *4'"2"  
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public void run() 
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{ F9PxSk_\9  
//获得文件长度 6nn*]|7  
//分割文件 /~1+i'7V.,  
//实例FileSplitterFetch llq<egZpm  
//启动FileSplitterFetch线程 |!ELV7?(  
//等待子线程返回 "oyo#-5z  
try{ &ZO0r ^  
if(bFirst) _a, s )  
{ F?0Ykjh3  
nFileLength = getFileSize(); OUnA;_  
if(nFileLength == -1) pa+hL,w{6  
{ :
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System.err.println("File Length is not known!"); M\j.8jG  
} E.h*g8bXe  
else if(nFileLength == -2) 0GwR~Z}Z  
{ 6tZI["\   
System.err.println("File is not access!"); awRX1:T#;O  
} ! nx{ X  
else 0GLM(JmK  
{ Gv&V|7-f0  
for(int i=0;i<nStartPos.length;i++) P \I|,  
{ P55fL-vo|}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }>\C{ClI  
} kh<2BOV  
for(int i=0;i<nEndPos.length-1;i++) F4QVAOM]U  
{ :jf3HG  
nEndPos = nStartPos[i+1]; kJU2C=m@e2  
}  " bG2:  
nEndPos[nEndPos.length-1] = nFileLength; PT ~D",k  
} G@0&8  
} sOY:e/_F  
+@UV?"d  
_c07}aQ ],  
//启动子线程 (FV >m  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (
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for(int i=0;i<nStartPos.length;i++) hH.G#-JO  
{ Jm@oDME_E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4H/OBR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), SbZ6t$"  
nStartPos,nEndPos,i); )b)zm2;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /v}`l  
fileSplitterFetch.start(); *8q.YuZ  
} +ZYn? #IQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !D6]J
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !-bB559Nv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2wn2.\v M  
nEndPos = " + nFileLength); \vNU,WO  
// fileSplitterFetch[nPos.length-1].start(); buC{r,  
$b\P|#A  
xno\s.H%]  
//等待子线程结束 =1! 'QUc  
//int count = 0; _F{C\}  
//是否结束while循环 ~&O%N  
boolean breakWhile = false; reVgqYp{{-  
}JfjX'  
?2a$*(  
while(!bStop) /reX{Y  
{ u2I Cl  
write_nPos();
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Utility.sleep(500); Efe 7gE'  
breakWhile = true; :Tc^y%b0  
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for(int i=0;i<nStartPos.length;i++) P>L +t`'  
{ 58K5ZZG  
if(!fileSplitterFetch.bDownOver) RSds8\tk  
{ )jj0^f1!j  
breakWhile = false; J,G lIv.A  
break;
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} GILfbNcd  
} }G=M2V<L  
if(breakWhile) 9L9sqZUB
 
break; TC. ,V_  
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//count++; SuznN L=/$  
//if(count>4) fM}#ON>Z  
// siteStop(); +p^u^a  
} l%ZhA=TKQ  
tkhCw/  
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System.err.println("文件下载结束！"); )Z$!PqRw@u  
} 67TwPvh  
catch(Exception e){e.printStackTrace ();} +(*DT9s+  
} iE{&*.q_}>  
{*KEP  
?upM>69{  
//获得文件长度 H]!"Zq k  
public long getFileSize() >p/`;Kq@  
{ A >$I -T+  
int nFileLength = -1; +"(jjxJm  
try{ !BI;C(,RL  
URL url = new URL(siteInfoBean.getSSiteURL()); #g=XUZ/"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V]N?6\Op  
httpConnection.setRequestProperty("User-Agent","NetFox"); Qd6FH2Pl  
=xrv~  
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int responseCode=httpConnection.getResponseCode(); {$r[5%L\H  
if(responseCode>=400) *A< 5*Db:F  
{ F?cK-.  
processErrorCode(responseCode); }Lv;

!  
return -2; //-2 represent access is error 9l,oP?  
} *H122njH+T  
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_
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String sHeader; #%s#c0TX  
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for(int i=1;;i++) q;U,s)Uz^  
{ sGb{9.WK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2oU_2P  
//Utility.log(in.readLine()); KG@8RtHsQ  
sHeader=httpConnection.getHeaderFieldKey(i); &{RDM~  
if(sHeader!=null) G j1_!.T  
{ 7|D+Ihy;  
if(sHeader.equals("Content-Length")) {[(h[MW#  
{ OTp]Xe/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \1`O_DF~o  
break; :jx4{
V  
} X|[`P<'N<  
} Y~Ifj,\  
else IAEAhqp  
break; 4=.so~9odX  
} ^&)|sP  
} b2]Kx&
!  
catch(IOException e){e.printStackTrace ();} jIF |P-  
catch(Exception e){e.printStackTrace ();} Bf:Q2slqI  
B:
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Utility.log(nFileLength); Q^I\cAIB  
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return nFileLength;  9akH  
} x:7IIvP  
8D].MI^  
bi:8(Q$w:`  
//保存下载信息（文件指针位置） iOdp
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private void write_nPos() fQ98(+6  
{ Th[dW<  
try{ d"N
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output = new DataOutputStream(new FileOutputStream(tmpFile)); _FEFx  
output.writeInt(nStartPos.length); Nluoqoac  
for(int i=0;i<nStartPos.length;i++) X@f}Q`{Ymj  
{ |%v^W3  
// output.writeLong(nPos); 6r_)sHf  
output.writeLong(fileSplitterFetch.nStartPos); mqJ_W[y7  
output.writeLong(fileSplitterFetch.nEndPos); -![|}p
X  
} +*^H#|!  
output.close(); v3qA":(w+(  
} b
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catch(IOException e){e.printStackTrace ();} *'X3z@R  
catch(Exception e){e.printStackTrace ();} s<Fl p  
} Kg$Mx  
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4fzZ;2sl}  
//读取保存的下载信息（文件指针位置） akT6^cP^  
private void read_nPos() >3_Gw4S*H  
{ BZxvJQ  
try{ Q,9oKg  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j.kG};f  
int nCount = input.readInt(); 9/;P->wy  
nStartPos = new long[nCount]; =2 kG%9  
nEndPos = new long[nCount]; EE'!|N3  
for(int i=0;i<nStartPos.length;i++)
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{ g1o8._f.  
nStartPos = input.readLong(); ;>YzEo  
nEndPos = input.readLong(); %IRi1EmN8  
} o]:9')5^  
input.close();
0RK!/:'  
} LK"69Qx?5q  
catch(IOException e){e.printStackTrace ();} |I|fMF2K  
catch(Exception e){e.printStackTrace ();} R$Q.sE  
} *,m;  
? qA]w9x  
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private void processErrorCode(int nErrorCode) @K]|K]cby  
{ *:NQ&y*uj  
System.err.println("Error Code : " + nErrorCode); :lzrgsW  
} HKr Mim-  
:c[L3rJl  
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//停止文件下载 _l]fkk[T  
public void siteStop() f9\X>zzB2|  
{ hzRYec(  
bStop = true; Gbw2E&a  
for(int i=0;i<nStartPos.length;i++) $\! 7 {6a  
fileSplitterFetch.splitterStop(); ,: ->ErP  

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} P2*<GjV`S/  
} `#gie$B{  
//负责部分文件的抓取 <o= 8FO  
**FileSplitterFetch.java ${)b[22":  
*/ #=v~8  
package NetFox; 9M9?%N:ra  
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import java.io.*; 5^KWCS7@  
import java.net.*; OC:T O|S:4  
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public class FileSplitterFetch extends Thread { Y#3c }qb  
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String sURL; //File URL
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long nStartPos; //File Snippet Start Position \_U$"/$4VH  
long nEndPos; //File Snippet End Position A={UL  
int nThreadID; //Thread's ID p6WX9\qS(  
boolean bDownOver = false; //Downing is over ,=mS,r7  
boolean bStop = false; //Stop identical D)'bH5  
FileAccessI fileAccessI = null; //File Access interface TW>WHCAm  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y|q3Wa  
{ ?NP1y9Y]i  
this.sURL = sURL; 8Bg;Kh6B  
this.nStartPos = nStart; \r>6`-cs]  
this.nEndPos = nEnd; k: ;WtBC6j  
nThreadID = id; 2wgg7[tGi  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pU7lnS[  
}  v<:R#  
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public void run() Lu0x (/  
{ F*K_+ ?m  
while(nStartPos < nEndPos && !bStop) $DUZ!zaH!  
{ 4YX3+oS  
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try{ A_#DJJMm  
URL url = new URL(sURL); !&Pui{F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D#/Bx[  
httpConnection.setRequestProperty("User-Agent","NetFox"); T${Q.zHY[!  
String sProperty = "bytes="+nStartPos+"-"; N{~YJ$!8  
httpConnection.setRequestProperty("RANGE",sProperty); ]]juN  
Utility.log(sProperty); @Pz
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InputStream input = httpConnection.getInputStream(); bNoW?8bZ  
//logResponseHead(httpConnection); z%LIX^q9  
HgkC~'  
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byte[] b = new byte[1024]; qWKAM@  
int nRead; ]P
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |qZ1|  
{ [=]4-q6UN  
nStartPos += fileAccessI.write(b,0,nRead); M[112%[+4  
//if(nThreadID == 1) ohGfp9H
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?8Cq{  
} k,F6Tx  
(DP &B%Sf  
\K<QmK  
Utility.log("Thread " + nThreadID + " is over!"); a+T.^koY  
bDownOver = true; K>l~SDcZ3  
//nPos = fileAccessI.write (b,0,nRead); 78H'ax9m  
} yqiq,=OvP  
catch(Exception e){e.printStackTrace ();} qc~iQSI  
} v2;`f+  
} }k G9!sf  
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//打印回应的头信息  xLZG:^(I  
public void logResponseHead(HttpURLConnection con) a"g!
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{ *%t^;&x?  
for(int i=1;;i++) M>8A\;"  
{ 3CGp`~Zf  
String header=con.getHeaderFieldKey(i); a,#j =  
if(header!=null) B[?CbU  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y,e B|  
Utility.log(header+" : "+con.getHeaderField(header)); 0|\$Vp  
else ~PahoRS  
break; \qK&q  
} ?vHU#  
} :+|Z@KB  
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public void splitterStop() fku<,SV$O4  
{ 4^OY C  
bStop = true; %lGfAYEM=  
} p >t#@Eu|  
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} u21EP[[,  
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/* t=O8f5Pf{  
**FileAccess.java be^6i:  
*//文件访问(定位，写) 9lH?-~9  
package NetFox; a1y-3z  
import java.io.*; WoRZW%  
N;j)
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public class FileAccessI implements Serializable{ K$_0`>[  
aC.~&MxFC  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9dUravC7  
RandomAccessFile oSavedFile; t#pS{.I  
long nPos; :|8M`18lZ  
{"QNJq#:  
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public FileAccessI() throws IOException 7 uKY24  
{ `o8/(`a  
this("",0); '>ssqBnI  
} M|`U"vO  
&,
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public FileAccessI(String sName,long nPos) throws IOException j*jo@N|  
{ }\:NuTf  
oSavedFile = new RandomAccessFile(sName,"rw"); &_|#
.  
this.nPos = nPos; )vb*Ef  
oSavedFile.seek(nPos); > eIP.,9  
} ]cMqahaY  
+sUFv)!4  
#"\gLr_:m  
public synchronized int write(byte[] b,int nStart,int nLen) ,+{LYF  
{ Pjjewy1}^  
int n = -1; i,4>0o?
  
try{ lun\`f 5Q  
oSavedFile.write(b,nStart,nLen); M`i\VG  
n = nLen; {I#]@,  
} mFaZio0GK  
catch(IOException e) D(RTV
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{ ^y1j.M@q  
e.printStackTrace (); (/j/>9iro  
} O7<]U_"I  
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return n; Vq?p|wy  
} ,+xB$e  
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} 9-DZU,`P  
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/* `FTy+8mw  
**SiteInfoBean.java =mpVYA  
*/ d0Qd$ .%A  
package NetFox; W=vP]x >J  
IrhA+)pdse  
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public class SiteInfoBean { fNt`?pWH  
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private String sSiteURL; //Site's URL
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private String sFilePath; //Saved File's Path a$"Hvrj  
private String sFileName; //Saved File's Name *b/`Ya4  
private int nSplitter; //Count of Splited Downloading File E5xzy/ZQ  
1Z
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public SiteInfoBean() IS 2^g>T#1  
{//nSplitter的缺省值为5 <_tT<5'[$u  
//default value of nSplitter is 5 D (mj7oB  
this("","","",5); ;y\IqiA{o  
} (Dl$kGn  
W$OG(m!W>  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) FUjl8b-|  
{ W7\f1}]H  
sSiteURL= sURL; }w<7.I  
sFilePath = sPath; S.m{eur!,E  
sFileName = sName; ,J>5:ht(6  
this.nSplitter = nSpiltter; 3.W@ }  
3
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} LBsluT  
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public String getSSiteURL() J/GSceHF  
{ $[&*Bj11Yg  
return sSiteURL; G<f@#[$'  
} af+IP_6 .  
80/F7q'tn  
.#Z%1U%P.  
public void setSSiteURL(String value) 2.zsCu4lj.  
{ 7-T{a<g  
sSiteURL = value; A1#%`^W9  
} #+5pgD2C  
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public String getSFilePath() dhr3,&+T2  
{ CS-uNG6  
return sFilePath; ayD}r#7  
} }mdAM6  
k |%B?\m  
}J1tdko#  
public void setSFilePath(String value) .CU5}Tv-  
{ mkF"   
sFilePath = value; q
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} Boz@bl mCB  
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&n?^$LTPY  
public String getSFileName() 9;Ox;;w  
{ :Q_<Z@2Y{  
return sFileName; M9@ri^x  
} TGe;HZ  
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public void setSFileName(String value) okv1K  
{ C{DvD'^  
sFileName = value; Dzs[GAQ]  
} YY!6/5*/]  
\y)  
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public int getNSplitter() ";Rtiiu  
{ $8[r9L!  
return nSplitter; }S$@ Ez6  
} UE ,t8j  
x{c/$+Z[  
<l9-;2L4  
public void setNSplitter(int nCount) !\L/[:n  
{ :!b'Vk  
nSplitter = nCount; 3*)ig@e6  
}  S"$m]  
} yH*6@P4:0=  
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D{d>5P?W  
/* HnCzbt@  
**Utility.java m"jV}@agX  
*/ ) ^3avRsC  
package NetFox; p4i]7o@  
16i"Yg!*  
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public class Utility { hcbv;[bG  
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o b|BXF  
public Utility() Y
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{ Zg`Mz _?  
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} qt^T6+faaQ  
ZMLg;-T.&4  
//线程睡眠 3UQ;X**F  
public static void sleep(int nSecond) B7<Kc  
{ Ch%m  
try{ -O!Zxg5x  
Thread.sleep(nSecond); y>|{YWbp?  
} z,:a8LB#[  
catch(Exception e) njnDW~Snb  
{ -7&Gi +]  
e.printStackTrace (); D<X.\})Md  
} D"ehWLj  
} Xy &uZ  
zyg  }F  
//日志 e^Ky<*Y  
public static void log(String sMsg) z)=+ F]  
{ ,
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System.err.println(sMsg); GSQ/NYK  
} u% n*gcY  
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V{&rQ@{W  
public static void log(int sMsg) `TPOCxM Mo  
{ \3jW~FV  
System.err.println(sMsg); 9{8GP  
} $gM8{.!  
} <K4,7J$}h  
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/* zf>5,k'x'A  
**TestMethod.java FwZ>{~?3  
*/ ~/ilx#d  
package NetFox; ^F"iP7   
@*DyZB  
\y{Tn@7  
public class TestMethod { T=:]]nf?M  
)Cw`"n  
;kJA'|GX  
public TestMethod() i^!ez5z  
{ ///xx/weblogic60b2_win.exe b(I2m  
try{ PeE/iZ.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6q6FB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %F*|;o7
s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *d',Vuv&[  
fileFetch.start(); d'Axum@  
} u}|%@=xn  
catch(Exception e){e.printStackTrace ();} >xn}N6Rj2~  
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UD y(v]  
} 2{.QjYw^  
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public static void main(String[] args) ^@_m "^C  
{ +/;*|  
new TestMethod(); zn@N'R/  
} (x$9~;<S*d  
} |fY/i] Ax  
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