http断点续传简单实现（java)

/* N=wB1gJ  
**SiteFileFetch.java <%!@cE+y  
*/ :!R+/5a  
package NetFox; |HL1.;1  
import java.io.*; ?e BN_a,r6  
import java.net.*; ThHK1{87X}  
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public class SiteFileFetch extends Thread { Uzc`,iV$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean b[/-lNrc  
long[] nStartPos; //开始位置 Y+D#Dv |  
long[] nEndPos; //结束位置 X&K1>dgWP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~O<Bs{8  
long nFileLength; //文件长度 6@bO3K|  
boolean bFirst = true; //是否第一次取文件 Jo2:0<VL  
boolean bStop = false; //停止标志 #t;@x_2yD\  
File tmpFile; //文件下载的临时信息 [1N*mY;  
DataOutputStream output; //输出到文件的输出流 GU_R6Wt+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7ZN0_Qs  
public SiteFileFetch(SiteInfoBean bean) throws IOException R7vO,kZ6Q  
{ Xbf
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siteInfoBean = bean; ab6KK$s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;Lz96R@}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  aj1Zi3h  
if(tmpFile.exists ()) Qq>M}  
{ AuWEy-q?  
bFirst = false; b^rPw@  
read_nPos(); y_QK _R<f  
} ,zO!`|I  
else @<;0h|  
{ W*N^Gp@  
nStartPos = new long[bean.getNSplitter()]; B!6?+<J"  
nEndPos = new long[bean.getNSplitter()]; }ufH![|[r  
} :H3qa2p  
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} d'q,:="c  
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public void run() r+ k5Bk'  
{ yKgA"NaM  
//获得文件长度 9F@Q  
//分割文件 J1KV?aR  
//实例FileSplitterFetch a}EO7tcg,  
//启动FileSplitterFetch线程 |]*]k`o<)  
//等待子线程返回 #[ipJ %  
try{ [HLXWu3  
if(bFirst) ^1nQDd*  
{ 4At{(fwW  
nFileLength = getFileSize(); V]&0"HX2r!  
if(nFileLength == -1) ha&2V=  
{ <#k(g\/R  
System.err.println("File Length is not known!"); H}Z\r2  
} W^v3pH-y#  
else if(nFileLength == -2) 3+ JkV\AF  
{ H$^IT#  
System.err.println("File is not access!"); -
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} AU0pJB'  
else +`'=K ;{U  
{ xy;u"JY*  
for(int i=0;i<nStartPos.length;i++) C3>&O?7J*7  
{ z3>ldT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2)cq!Zv  
} 3g ep_aC  
for(int i=0;i<nEndPos.length-1;i++) ,}?x
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{ sbqAjm}  
nEndPos = nStartPos[i+1]; S+9}W/  
} AYb-
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nEndPos[nEndPos.length-1] = nFileLength; \2]M&n GT  
} _[IOPHa"  
} <MdIQ;I8  
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//启动子线程 xw2dNJL  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :Q]P=-Y8  
for(int i=0;i<nStartPos.length;i++) A~0eJaq+  
{ IPHZ~'M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !:BmDX[<n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VCf/EkC  
nStartPos,nEndPos,i); JO[7_*s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); skeH~-`M@  
fileSplitterFetch.start(); p#;I4d G  
} \%BII>VS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6 rp(<D/_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {wJ8% ;Z7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "($"T v2  
nEndPos = " + nFileLength); Ar{7H)V:  
// fileSplitterFetch[nPos.length-1].start(); L*(Sh2=_  
.30eO_msK  
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//等待子线程结束 ^L?2y/  
//int count = 0; H6/n  
//是否结束while循环 " i!Xiy~  
boolean breakWhile = false; &) qs0  
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while(!bStop) o$q})!  
{ Ht4A   
write_nPos(); 9 `+RmX;m  
Utility.sleep(500); y?P4EVknM3  
breakWhile = true; WzhY4"p  
Q'~3Ik  
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for(int i=0;i<nStartPos.length;i++) 328gTP1  
{ A<p6]#t#X)  
if(!fileSplitterFetch.bDownOver) Q ym=L(X  
{ L)"E_  
breakWhile = false; K#;EjR4H  
break; 1ir~WFP  
} ?v,4seRuz  
} ;%^T*?t  
if(breakWhile) eKvQS}11  
break; BTnrgs#[  
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//count++; }AGdWt@  
//if(count>4) 'U*Kb  
// siteStop(); |2!cPf^8  
} q?$<{Z"  
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System.err.println("文件下载结束！"); M32Z3<  
} dOFK;  
catch(Exception e){e.printStackTrace ();} Oi4y~C_Xd  
} oi\e[qE  
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//获得文件长度 VRA0p[  
public long getFileSize() cr>"LAi  
{ ?TMrnR/d  
int nFileLength = -1; #xNXCBl]O  
try{ :\69N/uw`  
URL url = new URL(siteInfoBean.getSSiteURL()); }0 b[/ZwQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z"5ew
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httpConnection.setRequestProperty("User-Agent","NetFox"); (aX6jdvo  
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int responseCode=httpConnection.getResponseCode(); $;As7MI  
if(responseCode>=400) dS)c~:&+  
{ cUD}SOW  
processErrorCode(responseCode); M&ec%<lM  
return -2; //-2 represent access is error !_pryNcb  
} {Ax{N  
KiYz]IM$4  
*,#T&M7D  
String sHeader; &\ \)x.!  
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for(int i=1;;i++) c~v(bK  
{ }1? 2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =plU3D2  
//Utility.log(in.readLine()); ]`u_d}`  
sHeader=httpConnection.getHeaderFieldKey(i); uBA84r%{QQ  
if(sHeader!=null) kdp- 
|9  
{ 'J(B{B7|  
if(sHeader.equals("Content-Length")) D>m!R[!o  
{ G;yh$n<"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); AA~6r[*~  
break; WN9K*Tt~o&  
} nEbJ,#>Z  
} x$;kA}gy  
else !)+8:8H'  
break; 9,>u,  
} $Y&rci]  
} az;o7[rI^  
catch(IOException e){e.printStackTrace ();} |nq}#  
catch(Exception e){e.printStackTrace ();} g!.k>  
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Utility.log(nFileLength); 7FvtWE*  
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return nFileLength; C">w3#M%  
} Z0Df~ @  
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//保存下载信息（文件指针位置） a^QyYX}\qR  
private void write_nPos() k.("<)  
{ _5JwJcQ  
try{ 0VBbSn}Z<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); N;.}g*_+}  
output.writeInt(nStartPos.length); B?p18u$i#l  
for(int i=0;i<nStartPos.length;i++) OjRJyhzS*  
{ M qG`P  
// output.writeLong(nPos); F
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output.writeLong(fileSplitterFetch.nStartPos); xIb^x=|h  
output.writeLong(fileSplitterFetch.nEndPos); NvU~?WN  
} 0Z<&M|G  
output.close(); YH^h?s  
} Mz#<Vm4  
catch(IOException e){e.printStackTrace ();} WZ]f \S  
catch(Exception e){e.printStackTrace ();} MPI=^rc2  
} f%JC;Y  
*oca  
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//读取保存的下载信息（文件指针位置） w!N?:}P<N  
private void read_nPos() $bd2TVNV:  
{ ic]b"ItD  
try{ % XS2;V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); TE!+G\@  
int nCount = input.readInt(); AQ` `Dp  
nStartPos = new long[nCount]; #FQkwX'g  
nEndPos = new long[nCount]; jt?.g'  
for(int i=0;i<nStartPos.length;i++) "0edk"hk  
{ Obb"#
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nStartPos = input.readLong(); '|JBA.s|  
nEndPos = input.readLong(); j|/4V  
} qPI1\!z6  
input.close(); dqu+-43I|  
} jQIb :\0#  
catch(IOException e){e.printStackTrace ();} g!*5@k|C  
catch(Exception e){e.printStackTrace ();} yv2N5IQ>{V  
} ]`,jaD  
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private void processErrorCode(int nErrorCode) 2MQ XtK  
{ <*'%Xgm  
System.err.println("Error Code : " + nErrorCode); AZgeu$:7p<  
} yy*8Aw}  
A)j',jE&1  
~#^suy?  
//停止文件下载 `z)q/;}fC  
public void siteStop() l1?$quM^V  
{ do$+ Eh  
bStop = true; a#L:L8T;j  
for(int i=0;i<nStartPos.length;i++) d[7B,l:RN  
fileSplitterFetch.splitterStop(); PDi]zp9>H  
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9>I&Z8J$M  
} -\dcs?  
} KyQd6 1  
//负责部分文件的抓取 ??u*qO:p  
**FileSplitterFetch.java dvX
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*/  'K7m!y  
package NetFox; \Hs*46@TC  
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+$;*"o  
import java.io.*; hq|I%>y  
import java.net.*; H,q-*Kk  
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92 oUQ EK  
public class FileSplitterFetch extends Thread { ^1mnw@04  
uK;&
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String sURL; //File URL ~cL)0/j}  
long nStartPos; //File Snippet Start Position WM8])}<L  
long nEndPos; //File Snippet End Position "PePiW(i+  
int nThreadID; //Thread's ID kE`Fg(M  
boolean bDownOver = false; //Downing is over kuI$VC  
boolean bStop = false; //Stop identical pAtt=R,Ht  
FileAccessI fileAccessI = null; //File Access interface /:.p{y  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -SlAt$IJ  
{ O/b1^ Y   
this.sURL = sURL; K3.z>.F'h  
this.nStartPos = nStart; wvcj*{7[  
this.nEndPos = nEnd; J
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nThreadID = id; me YSW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Q79WGW  
} E0*62OI~O  
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public void run() 8'-E>+L   
{ 7TB&Q*Zf  
while(nStartPos < nEndPos && !bStop) J;S Z"I'  
{ gHox>r6.A  
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try{ ;-quK%VO!  
URL url = new URL(sURL); #}+_Hy  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Zfc{}ius  
httpConnection.setRequestProperty("User-Agent","NetFox"); zEk/#&  
String sProperty = "bytes="+nStartPos+"-"; d;g]Oe
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httpConnection.setRequestProperty("RANGE",sProperty); xzb{g,c   
Utility.log(sProperty); <Q@{6  
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InputStream input = httpConnection.getInputStream(); #&Fd16ov  
//logResponseHead(httpConnection); `{&l _  
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5 J 7XVe>  
byte[] b = new byte[1024]; %:.IG.`d  
int nRead; 1>
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) v M $Tn  
{ 97n,^t2F\  
nStartPos += fileAccessI.write(b,0,nRead); J@RV^2  
//if(nThreadID == 1) uz@lz +  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rW[7 _4  
} F>ps&h  
\ocC'FmE  
66'AaA;0^i  
Utility.log("Thread " + nThreadID + " is over!"); z<u@::  
bDownOver = true; TL@{yJ;s  
//nPos = fileAccessI.write (b,0,nRead); ,%]xT>kH  
} ee*E:Ltz\  
catch(Exception e){e.printStackTrace ();} yG:Pg MrB  
} #4{9l SbU  
} E|ZLz~  
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//打印回应的头信息 fHacVjJ  
public void logResponseHead(HttpURLConnection con) L7B(abT9e  
{ 0[!38  
for(int i=1;;i++) QO3QR/Ww  
{ gg QI  
String header=con.getHeaderFieldKey(i); Hv .C5mo  
if(header!=null) ?Q/9aqHe;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "%)^:('Ki  
Utility.log(header+" : "+con.getHeaderField(header)); S@vLh=65  
else 
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break; ?iaD;:'qE  
} QVQ?a&HYS  
} \bumB<w(]  
/@f3|L<1@V  
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public void splitterStop() a*nx2d  
{ \&5t@sC  
bStop = true; ^n8r mh_%  
} y w>T1  
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} . [5{  
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/* \hFIg3  
**FileAccess.java ^PI8Bvs>j  
*//文件访问(定位，写) :,BKB*a\  
package NetFox; d}RR!i`<N  
import java.io.*; cG~-OHU  
(lR9x6yf  
7iBN!"G0  
public class FileAccessI implements Serializable{ ?\
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p  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 O6$d@r;EK]  
RandomAccessFile oSavedFile; "iY=1F"\R  
long nPos; OFe?T\dQn  
Y
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public FileAccessI() throws IOException KWH l+pL  
{ :gJ?3LwTf  
this("",0); *eonXJYD  
} YB1uudW9  
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public FileAccessI(String sName,long nPos) throws IOException >=Pn\"j  
{ rr=e  
oSavedFile = new RandomAccessFile(sName,"rw"); cq,0?2R`t  
this.nPos = nPos; M$0-!$RY  
oSavedFile.seek(nPos); mjtmN0^SR  
} 1SGLA"r  
da
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public synchronized int write(byte[] b,int nStart,int nLen) C>:'@o Z  
{ 3</gK$f2  
int n = -1; L d;))e  
try{ BQ7p<{G  
oSavedFile.write(b,nStart,nLen); 6,q}1-  
n = nLen; A3|hFk  
} TC+
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catch(IOException e) EDf"1b{PX  
{ W1T% Q88  
e.printStackTrace (); Gjh8>(  
} F?B`rw@xr  
;"K;D@xzh]  
r$ 8^K\oF  
return n; &Q`{ Gk  
} t3// U#  
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}  UqwU3  
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/* lIUaGz|  
**SiteInfoBean.java EIrAq!CA  
*/ L<62-+e`  
package NetFox; wJ%;\06  
TF1,7Qd  
"-T[D9(A  
public class SiteInfoBean { ``?79MJ5  
6^l|/\Y{  
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private String sSiteURL; //Site's URL BH"Op
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private String sFilePath; //Saved File's Path NZoNsNu*C.  
private String sFileName; //Saved File's Name )4MM>Q  
private int nSplitter; //Count of Splited Downloading File =f/CBYNw@V  
"
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public SiteInfoBean() MfA@)v  
{//nSplitter的缺省值为5 1p5n}|  
//default value of nSplitter is 5 {U'\2Ge<m  
this("","","",5); C==yl"w  
} XU y[l  
[o"<DP6w  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g2;lEW  
{ fg)VO6Wo&  
sSiteURL= sURL; 1.tAl6]  
sFilePath = sPath; 8g0VTY4$jP  
sFileName = sName; lDSF  
this.nSplitter = nSpiltter; 64i*_\UKe  
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{sfA$ d0  
} uc>":V  
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public String getSSiteURL() I`f5)iF?0  
{ Fq$r>tmV  
return sSiteURL; 4`B3Kt`o  
} Zz1nXUZ  
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public void setSSiteURL(String value) iInWw"VbKe  
{ hUC157  
sSiteURL = value; r7,}"Pl  
} '451H3LC0  
n
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>
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public String getSFilePath() lSg[
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{ =C2KHNc  
return sFilePath; [j}JCmWY   
} u"uL
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public void setSFilePath(String value) %q}[ZD/HD  
{ 8t3m$<7  
sFilePath = value; ua)jGif  
} \BuyJskE  
f S[-K?K  
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public String getSFileName() "M, 1ElQ  
{ X$;&Mdo.  
return sFileName; *s,[Uy![  
} J#48c'  
lxm/*^  
tYXE$i  
public void setSFileName(String value) 4-t^?T:qF  
{ i!zFW-*5  
sFileName = value; xorafL  
} CxTmW5l  
|mP};&b  
n m<?oI*\  
public int getNSplitter() )q[P&f(h  
{ a%e`  
return nSplitter; d\ 8v VZ  
} L;* s-j6y  
qXg&E}]:=  
puJB&u"4L  
public void setNSplitter(int nCount) ]q.%_  
{ D3yTN"  
nSplitter = nCount; .G8>UXX  
} QXZyiJX}  
} !uQT4<g  
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rNR7}o~qo  
/* HJ]xZ83pC  
**Utility.java iCPm7AU  
*/ HiA E9  
package NetFox; V6X )L>!xx  
)
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Ln4]uqMG.  
public class Utility { *qwN9b/!  
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BS*79heY  
public Utility() S
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{ 1o`1W4Q  
0+e=s0s.  
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} &t[[4+Qt  
Cgx:6TRS  
//线程睡眠 gS5REC4I/  
public static void sleep(int nSecond) ZC N}iQu4  
{ (dq_,LI  
try{
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Thread.sleep(nSecond); s/tLY/U/  
} w'K7$F51  
catch(Exception e) Hu"$)V  
{ w.q`E@ T*  
e.printStackTrace (); gz~oQ l)zJ  
} 1'qXT{f/~  
} l8FJ\5'M  
,c&u\W=p  
//日志 -qc'J<*^4  
public static void log(String sMsg) N1Vj;-  
{ ^%$IdDx  
System.err.println(sMsg); 0]4X/u#N  
} YVMvT>/,  
Sb[>R(0:  
c["1t1G  
public static void log(int sMsg) ^Kz?SO  
{ O2Qmz=%  
System.err.println(sMsg); ?>
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} (%X *b.n=  
} \6|y~5Hw{r  
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k+9F;p7  
/* \p(S4?I7  
**TestMethod.java ^*}D*=>\  
*/ G`!,
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package NetFox; 6CyByj&  
1Vy8eI`4  
a fa\6]m  
public class TestMethod { M7/5e3  
Rn
kV)ed(  
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public TestMethod() !0l|[c4 e>  
{ ///xx/weblogic60b2_win.exe Q#%LIkeq  
try{ 9K&$8aD  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~!({Unt+'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); nk|(cyt)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .4a|^ vT  
fileFetch.start(); &}u_e`A  
} &`m.]RV  
catch(Exception e){e.printStackTrace ();} z -?\b^  
&E]) sJ0  
(')t>B1Z  
} DNmC   
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public static void main(String[] args) &3iI\s[  
{ Ov(k:"N  
new TestMethod(); (hwzA *(c  
} 1jx?zvE,  
} iK4\N;H  
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