http断点续传简单实现（java)

/* 5!qLJmd=  
**SiteFileFetch.java kk ZM
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*/ +m4?a\U  
package NetFox; x }i'2  
import java.io.*; qkD9xFp  
import java.net.*; )TOKHN  
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public class SiteFileFetch extends Thread { \ mg  
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SiteInfoBean siteInfoBean = null; //文件信息Bean <ELqj2`
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long[] nStartPos; //开始位置 O6]X\Cwj%  
long[] nEndPos; //结束位置 dF'oZQz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 iCdq-r/r!6  
long nFileLength; //文件长度 23'Ac,{  
boolean bFirst = true; //是否第一次取文件 Bi|-KS.9  
boolean bStop = false; //停止标志 E[M.q;rM  
File tmpFile; //文件下载的临时信息 %:Y'+!bX  
DataOutputStream output; //输出到文件的输出流 W<M\b#  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =po5Q6@i  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3$PGLM  
{ pXf5/u8&  
siteInfoBean = bean; H;Gd
  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bix}#M  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SO
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if(tmpFile.exists ()) jN{+$ @cI  
{ zfK3$|  
bFirst = false; 28O3N;a  
read_nPos(); =z9FjK  
} 1G 63eH)!  
else I ka V g L  
{ ~i=5NUE  
nStartPos = new long[bean.getNSplitter()]; lQ|i Ws  
nEndPos = new long[bean.getNSplitter()]; \<x{U3q5  
} {%QWv%|  
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} M][Zu[\*  
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public void run() T9]:, z  
{ jo ~p#l.'  
//获得文件长度 7jYW3  
//分割文件 :+UahwiRD"  
//实例FileSplitterFetch HfA@tZ5q|U  
//启动FileSplitterFetch线程 <%=@Ue  
//等待子线程返回 zN>tSdNkI-  
try{ o&kgRv[  
if(bFirst) Rs53R$PIR  
{ +6\1 d5  
nFileLength = getFileSize(); $<d3g:  
if(nFileLength == -1) WGI4DzKa  
{ )Qc>NF0  
System.err.println("File Length is not known!"); mH7Mch| m  
} h;t5v6["  
else if(nFileLength == -2) b0[H{q-z{X  
{ yA^+<uz}  
System.err.println("File is not access!"); |=#uzp7*  
} 2IFEl-IB[  
else =
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{ %$zX a%A  
for(int i=0;i<nStartPos.length;i++) p"o_0{8  
{ #i|AE`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); o'!WW  
} S3&lkN5  
for(int i=0;i<nEndPos.length-1;i++) Tw!_=zy(Gw  
{ )X5en=[)O  
nEndPos = nStartPos[i+1]; Schvwlm~i  
} 7=pJ)4;ZA  
nEndPos[nEndPos.length-1] = nFileLength; kT4Oal+4  
} Hb@PQ
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} UYsyVY`Fm|  
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//启动子线程 H1a<&7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P: )YKro]  
for(int i=0;i<nStartPos.length;i++) 3L-}B#tI  
{ P{o//M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I]0 D*z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K5:>  
nStartPos,nEndPos,i); .u&GbM%Ga  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [TX5O\g![  
fileSplitterFetch.start(); Un{9reX5  
} @M8vPH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yn KgNi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9vJ'9Z2\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .?;"iv+  
nEndPos = " + nFileLength); #mH4\s  
// fileSplitterFetch[nPos.length-1].start(); Oh/2$72  
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//等待子线程结束 d(;Qe}ok>  
//int count = 0; Wf5ohXm>  
//是否结束while循环 m7NrS?7  
boolean breakWhile = false; p^?]xD(  
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while(!bStop) D|X@aUp8}  
{ (xlAS  
write_nPos(); %$}*y   
Utility.sleep(500); ljw>[wNv  
breakWhile = true; GB` G(a  
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for(int i=0;i<nStartPos.length;i++) _J-3{a  
{ `T~~yM)q  
if(!fileSplitterFetch.bDownOver) rd!4u14  
{ /\|Behif  
breakWhile = false; l|'{Cb   
break; (}&O)3)  
} 0v'FE35~s  
} 'I1^70bB  
if(breakWhile) /Q2{w>^DK  
break; H<bB@(i  
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//count++; EmubpUS;  
//if(count>4) br_D Orq|  
// siteStop(); G5'HrV  
} J#jx)K!  
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System.err.println("文件下载结束！"); Z{spo=  
} [{cMEV&  
catch(Exception e){e.printStackTrace ();} OAd}#R\U  
} (| X?  
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\1cJ?/$_Of  
//获得文件长度 ?(P3ZTk?.  
public long getFileSize() :igURr
  
{ V j"B/@  
int nFileLength = -1; j SXVLyz  
try{ KI~M.2pk  
URL url = new URL(siteInfoBean.getSSiteURL()); n0<I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K!BS?n;  
httpConnection.setRequestProperty("User-Agent","NetFox"); >r
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int responseCode=httpConnection.getResponseCode(); PcQqdU^!  
if(responseCode>=400) nK;c@!~pS  
{ EG3?C  
processErrorCode(responseCode); 92)e/t iP  
return -2; //-2 represent access is error @?\[M9yK  
} tv8}O([  
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String sHeader; E4dN,^_ F!  
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for(int i=1;;i++) 1Wy0#?L  
{ N)N\iad^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Jx_BjkF  
//Utility.log(in.readLine()); s6| S#  
sHeader=httpConnection.getHeaderFieldKey(i); 2#?qey  
if(sHeader!=null) l
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{ CAvyS  
if(sHeader.equals("Content-Length")) t>izcO  
{ 1#-=|:U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TSHQ>kP  
break; m C&*K  
} \C.s%m  
}
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else vS_Ji<W~E  
break; sGs_w:Hn  
} 7.N~e}p8  
} YdNmnB%J  
catch(IOException e){e.printStackTrace ();} |Xv]s61  
catch(Exception e){e.printStackTrace ();} $m)[> C  
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Utility.log(nFileLength); |SfmQ;  
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return nFileLength; 5fqQ;r  
} ]E!b&  
/a:sWmxMT  
c mI&R(  
//保存下载信息（文件指针位置） uF89B-t  
private void write_nPos() 236,o {9e  
{ TowRY=#jiS  
try{ ! >l)*jN8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); V$';B=M  
output.writeInt(nStartPos.length); #`(-Oj2hH  
for(int i=0;i<nStartPos.length;i++) MX\v2["FoV  
{ C}>Pn{wY9  
// output.writeLong(nPos); P>s3Rh3:  
output.writeLong(fileSplitterFetch.nStartPos); F vt5vQ  
output.writeLong(fileSplitterFetch.nEndPos); b6y/o48  
} y2:~_MD  
output.close(); eW>Y*l%B  
}  a8wQ,  
catch(IOException e){e.printStackTrace ();} @0{vA\  
catch(Exception e){e.printStackTrace ();} =2rkaBFC  
} 1?}5.*j<  
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//读取保存的下载信息（文件指针位置） G&2`c\u{  
private void read_nPos() ;H;c Sn5uL  
{ RAps`)OR?  
try{ 0l&#%wmJ,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ZIo%(IT!c  
int nCount = input.readInt(); c&AJFED]<  
nStartPos = new long[nCount]; ?1kXV n$  
nEndPos = new long[nCount]; xYUC|c1Q9  
for(int i=0;i<nStartPos.length;i++) XzF-g*e  
{ k9Xv@v  
nStartPos = input.readLong(); YLVZ]fN=>  
nEndPos = input.readLong(); wq@{85  
} _)U[c;^6  
input.close(); ^;@Q3~DpP%  
} Y)oF;ko:  
catch(IOException e){e.printStackTrace ();} ^vA"3Ixb!  
catch(Exception e){e.printStackTrace ();} $
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} }> pNf  
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private void processErrorCode(int nErrorCode) Z\9DtvV
 
{ gfY1:0  
System.err.println("Error Code : " + nErrorCode); BhcTPQsW  
} PZjK6]N\  
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//停止文件下载 V^[B=|56  
public void siteStop() Q]v><  
{ n |e=7?H8  
bStop = true; +8#hi5e  
for(int i=0;i<nStartPos.length;i++) Q6lC:cB<  
fileSplitterFetch.splitterStop(); H0P:t(<Gt  
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} Z;qgB7-M  
} ]8;2Oh   
//负责部分文件的抓取 9ER!K  
**FileSplitterFetch.java A0f98?j^  
*/ {dF_=`.  
package NetFox; p}:"@6
  

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import java.io.*; 3
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import java.net.*; .WV5Gf)  
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public class FileSplitterFetch extends Thread { [d^ [Y:I'\  
#vs=yR/tn{  
dPmtU{E<M  
String sURL; //File URL e_v_y$  
long nStartPos; //File Snippet Start Position )U5Ba^"fI  
long nEndPos; //File Snippet End Position }JlrWJRi  
int nThreadID; //Thread's ID L$ki>._i\  
boolean bDownOver = false; //Downing is over d09qZj>  
boolean bStop = false; //Stop identical 2k]Jkd,E  
FileAccessI fileAccessI = null; //File Access interface &hco3HfW  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException XK=-$2n  
{ ,}jey72/k  
this.sURL = sURL; 76BA1x+G  
this.nStartPos = nStart; c*c 8S~6  
this.nEndPos = nEnd; C>gC99  
nThreadID = id; x3L0;:Fx8P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .2v)x  
} VTIRkC wl@  
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public void run() wk[4Qs
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{ hqwDlapTt  
while(nStartPos < nEndPos && !bStop) ?Fp2W+M j  
{ ?Zv>4+Y'  
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try{ lVra&5  
URL url = new URL(sURL); p/WE[8U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N*NGC!p`N  
httpConnection.setRequestProperty("User-Agent","NetFox"); yZyB.wT  
String sProperty = "bytes="+nStartPos+"-"; oH>G3n|U^  
httpConnection.setRequestProperty("RANGE",sProperty); _p^&]eQ+k#  
Utility.log(sProperty); 5`QN<4?%  
dc=~EG-_rM  
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InputStream input = httpConnection.getInputStream();  57`*5X  
//logResponseHead(httpConnection); YU6D;  
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byte[] b = new byte[1024]; #-{^={p"  
int nRead; /)/>/4O  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &(/QJ`*8  
{ mF`%Z~}b  
nStartPos += fileAccessI.write(b,0,nRead); ';iLk[  
//if(nThreadID == 1) ,he1WjL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cak-J~=  
} R^+,D  
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Utility.log("Thread " + nThreadID + " is over!"); 5q95.rw  
bDownOver = true; ToE^%J4  
//nPos = fileAccessI.write (b,0,nRead); @?CEi#-  
} -*AUCns#  
catch(Exception e){e.printStackTrace ();} sMHP=2##  
} uz'MUT(68  
} \_|g}&}6Y  
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< s1  
//打印回应的头信息 -![>aqWmj1  
public void logResponseHead(HttpURLConnection con) </-aG[Fi  
{ a"bael  
for(int i=1;;i++) ibL   
{ JthW"{E  
String header=con.getHeaderFieldKey(i); Q)L6+gW^  
if(header!=null) W~Ae&gcn#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); v FWg0 $,  
Utility.log(header+" : "+con.getHeaderField(header)); ]!'9Y}9a  
else dO!5`
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break; S<O
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} i{2ny$55h  
} P`TJqJiY~  
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public void splitterStop() E;-*LT&{  
{ s^zX9IVnp  
bStop = true; i=AQ1X\s  
} ujan2'YT  
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6!$
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} <&MY/vV  
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/* ZMGthI}~-  
**FileAccess.java sMNhD/bb  
*//文件访问(定位，写) E9~}%&  
package NetFox; PCs`aVZ  
import java.io.*; l,@rB+u
 
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public class FileAccessI implements Serializable{ (Y:?qy  
AZf$XHP2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +XoY@|Djd  
RandomAccessFile oSavedFile; =kDh:&u%  
long nPos; +Vw]DLWR  
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public FileAccessI() throws IOException CA]u3bf~  
{ 2kW*Z7@D  
this("",0); A| s\5"??  
} ;nbbKQ]u  
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public FileAccessI(String sName,long nPos) throws IOException i>{.Y};  
{ [|tlTk  
oSavedFile = new RandomAccessFile(sName,"rw"); #H-
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this.nPos = nPos; Ac8t>;=&  
oSavedFile.seek(nPos); Mi:i1i cdn  
} v
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public synchronized int write(byte[] b,int nStart,int nLen) $b`~KMO  
{ 4H_Q
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int n = -1; e=sV>z>  
try{ Yc2dq e>  
oSavedFile.write(b,nStart,nLen); 0}q
nq"  
n = nLen; Jm[_X  
} {vox x&UX  
catch(IOException e) O%*:fd,o-  
{ -W.bOr  
e.printStackTrace (); Wo+^R%K'4  
} Y^-D'2P]P  
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return n; h42dk(B  
} 8Bwm+LYr-  
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} O*udVE>  
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/* 9^1li2zk{  
**SiteInfoBean.java @~C C$Y$  
*/ h%8C_mA  
package NetFox; o@uZU4MM  
n0%5mTUN  
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public class SiteInfoBean { wuKr9W9Xa  
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tNC;CP#R+  
private String sSiteURL; //Site's URL ^7iP!-w/  
private String sFilePath; //Saved File's Path bBgyL
yg  
private String sFileName; //Saved File's Name {4YD_$4W  
private int nSplitter; //Count of Splited Downloading File e {805^X}  
*^i"q\n5(  
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public SiteInfoBean() Z7J4rTA  
{//nSplitter的缺省值为5 Xz\X 8I  
//default value of nSplitter is 5 Rv Uw,=  
this("","","",5); Wp(Rw4j  
} gP
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e`bP=7`
0  
{ ~*hCTqHvN  
sSiteURL= sURL; j5MUP&/g3  
sFilePath = sPath; t`pbEjE0K  
sFileName = sName; Z
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this.nSplitter = nSpiltter; rj/1AK  
L!0}&i;u~5  
&}!AjA)  
} SlI wLv^  
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public String getSSiteURL() q_z;kCHM  
{ =h,J!0Y  
return sSiteURL; BY>]6SrP  
} hUe\sv!x?  
;!,I1{`  
.Z(Q7j^  
public void setSSiteURL(String value) (N?nOOQ  
{ *X8Pa;x  
sSiteURL = value; EL(BXJrx{  
} .\mkgAlyaM  
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public String getSFilePath() Dn:1Mtj-  
{ _71&".A  
return sFilePath; ?$.x%G+  
} cf%aOHYI*  
E'^ny4gL  
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public void setSFilePath(String value) <['ucp  
{ d"OYq
 
sFilePath = value; 3hfv^H  
} 5,9cD`WR^  
\]
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=}'7}0M_=  
public String getSFileName() 2?kVbF  
{ R{UZCFZ  
return sFileName; Zx^R-9  
} gdkHaLL"  
*0x!C8*`Xe  
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public void setSFileName(String value) 2hY"bpGW  
{ k_`YVsEYP  
sFileName = value; qAi:F=> X  
} 4"#F=f0  
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public int getNSplitter() %J+k.UrM  
{ 8^!ib/@v"  
return nSplitter; 1pP q)}=+  
} py$i{v
%  
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public void setNSplitter(int nCount) EOXuc9>G  
{
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nSplitter = nCount; W4"1H0s`l  
} J3hhh(  
} V$bq|r  
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/* CEJqo8ds  
**Utility.java >=/DCQ$  
*/ 0Ok[`r`  
package NetFox; Sobp;OZ5  
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public class Utility { Kh{_Bd
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r=#v@]zB  
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public Utility() (dP9`Na]  
{ 3`Dyrj#!  

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} HpS1(%d"  
,15$$3z/E  
//线程睡眠 zS'{F>w  
public static void sleep(int nSecond) ! q+>'Mt  
{ ;iz3Bf1o  
try{ zC`ediyu  
Thread.sleep(nSecond); e#@u&+K/f  
} irMBd8WG  
catch(Exception e) ?f*>=;7=  
{ |-xKH.'n  
e.printStackTrace (); $]MOAj"LH  
} U04)XfO;]  
} cFHSMRB|P  
vj"['6Xa  
//日志 KN~Repcz@  
public static void log(String sMsg) uFL!*#A  
{ @%!Gj{
 
System.err.println(sMsg); Y#FSU#a$<  
} Hk?E0.  
y1#QP3'Z1  
2[

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public static void log(int sMsg) 06I(01M1  
{ USH>`3  
System.err.println(sMsg); +1Pu29B0  
} G$s=P  
} 0oo_m6ie&  
m}+_z^@j9  
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/* `[~LMV&2U  
**TestMethod.java sI@kS^  
*/ OT#foP  
package NetFox; aZ}z/.b]  
(, $Lp0mB7  
J7k=5Fqej;  
public class TestMethod { zwK$ q=-:  
W3&~[DS@~  
Ox6^=D"  
public TestMethod() h([qq<Lzs  
{ ///xx/weblogic60b2_win.exe \3whM6tK  
try{ 0gr#<(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2>.>q9J(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0$|wj^?U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); soqnr" 1  
fileFetch.start(); wD SSgk  
} Y^gIvX  
catch(Exception e){e.printStackTrace ();} j&0t!f.Rv  
<<6gsKP  
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} ~
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public static void main(String[] args) \{1Vjo  
{ A&_v:z4y/  
new TestMethod(); Pcr;+'q  
} <9`/Y"\p  
} RMa#z [{0  
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