http断点续传简单实现（java)

/* *%%n9T  
**SiteFileFetch.java cQ3p|a `  
*/ @c}Gw;e  
package NetFox; }N:QB}7'_  
import java.io.*; y,`q6(&  
import java.net.*;
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public class SiteFileFetch extends Thread { _>^Y0C[?5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean lB7/oa1]>  
long[] nStartPos; //开始位置 iz+,,UH  
long[] nEndPos; //结束位置 }4Q3S1|U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X@/X65=[  
long nFileLength; //文件长度 Z1p%6f`  
boolean bFirst = true; //是否第一次取文件 w9Nk8OsL  
boolean bStop = false; //停止标志 &SPIu,  
File tmpFile; //文件下载的临时信息 M #%V%<  
DataOutputStream output; //输出到文件的输出流 pV1;gqXNS  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3f:]*U+O  
public SiteFileFetch(SiteInfoBean bean) throws IOException '1d0 *5+6k  
{ rEWuWv$  
siteInfoBean = bean; "$q"Kilj%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ob/HO(h3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); oWggh3eXk  
if(tmpFile.exists ()) dvglh?7d  
{ !:~C/B{  
bFirst = false; '1zC|:,  
read_nPos(); }:*?w>=  
} Xd.y or
 
else COd~H  
{ -L2?Tap  
nStartPos = new long[bean.getNSplitter()]; U^-RyE!}  
nEndPos = new long[bean.getNSplitter()]; r l;Y7
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} C
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} a;(,$q3M  
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public void run() @f-rS{  
{ X.rbJyKe  
//获得文件长度 z;>O5a>z  
//分割文件 J+`gr_&  
//实例FileSplitterFetch TC ;Aj|)N  
//启动FileSplitterFetch线程 [7[$P.MS{  
//等待子线程返回 ]ed7Q3lq  
try{ [?da BXS  
if(bFirst) :ra[e(l9  
{ [p)2!]y  
nFileLength = getFileSize(); y }h2
  
if(nFileLength == -1) YL[y3&K  
{ <4^y7]]F  
System.err.println("File Length is not known!"); u%Z4 8wr  
} aZmbt,.V  
else if(nFileLength == -2) {q&A/  
{ p4K 8L'nZ  
System.err.println("File is not access!"); @s\}ER3  
} =4Jg6JKYg  
else 2O2d*Ld>  
{ (unJwh{7Q  
for(int i=0;i<nStartPos.length;i++) YLV$#a3  
{ D~TK'&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oJI+c+e"  
} NNRKYdp,  
for(int i=0;i<nEndPos.length-1;i++) MF$NcU  
{ 5=!aq\ 5  
nEndPos = nStartPos[i+1]; r?`7i'  
} u;8
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nEndPos[nEndPos.length-1] = nFileLength; [VouG{  
} x/ P\qI  
} Fd._D"  
{[+Q\<  
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//启动子线程 ]O~/k~f  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; x6|
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for(int i=0;i<nStartPos.length;i++) ?!bWUVC)_  
{  M|>-q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S7CD#Y[s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), aIN?|Ch  
nStartPos,nEndPos,i); /ZSdY_%s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u#Uc6? E  
fileSplitterFetch.start(); UZE%!OWpeK  
} a0 w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HGW;]8xl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {dV!sQD  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <Q.-WV]Z  
nEndPos = " + nFileLength); nm<S#i*  
// fileSplitterFetch[nPos.length-1].start(); u?8e>a  
puGy`9eKv1  
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//等待子线程结束 !i=k=l=  
//int count = 0; ,Lw '3  
//是否结束while循环 >Wj8[9zf  
boolean breakWhile = false; 2K2jko9'a  
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while(!bStop) }$s._)a  
{ 9K{0x7~  
write_nPos(); uC1
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Utility.sleep(500); et}s yPH  
breakWhile = true; %W$?*Tm  
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for(int i=0;i<nStartPos.length;i++) R=HcSRTkA  
{ vu)V:y  
if(!fileSplitterFetch.bDownOver) Umk!m] q  
{ jyjK~!0  
breakWhile = false; Q__1QUu  
break; i)d'l<RA  
} R<1[hH9"o  
} /?:]f  
if(breakWhile) p5=VGKp  
break; \"A~ks~  
'
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//count++; cUr'mb  
//if(count>4) VW9BQs2w  
// siteStop(); vlZ?qIDe  
} K7d]p0d'  
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System.err.println("文件下载结束！"); ZlYb8+rW  
} 3)qtz_,H/g  
catch(Exception e){e.printStackTrace ();} <}Rr C#uiA  
} ^VB_>|UN4  
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//获得文件长度 1)=sbFtS  
public long getFileSize() w1|YR  
{ KP!ctlP~  
int nFileLength = -1; _6Fj&mw(u  
try{ }U7><I  
URL url = new URL(siteInfoBean.getSSiteURL()); 8I=migaxP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M7n|Z{?(  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1)wzSEV@  
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int responseCode=httpConnection.getResponseCode(); _p=O*$b.  
if(responseCode>=400) K)t+lJ  
{ }\!38{&  
processErrorCode(responseCode); C$$lJ=>  
return -2; //-2 represent access is error 8'Ph/L,  
} D'+kzb@  
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String sHeader; fdTyY ;  
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for(int i=1;;i++) kVe_2oQ_>  
{ Y$?<y   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); slMWk;fmD}  
//Utility.log(in.readLine()); Y:XxTa*  
sHeader=httpConnection.getHeaderFieldKey(i); c
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if(sHeader!=null) ByPzA\;e  
{ &U8W(NxN  
if(sHeader.equals("Content-Length")) W.A
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{ g&"__~dS-F  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~;0J4hR  
break; p
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} :K_JY   
} /xRPQ|  
else `P<m`*  
break; {!hA^[}|  
} Jm8#M z  
} D0=H&Z[  
catch(IOException e){e.printStackTrace ();} @l:\Ka~TS  
catch(Exception e){e.printStackTrace ();} u;*Wc9>sU  
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Utility.log(nFileLength); 29E9ZjSK  
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return nFileLength; M[R\URu8  
} !fcr3x|Y~M  
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//保存下载信息（文件指针位置） 9RoN,e8!  
private void write_nPos() BJI R !J  
{ +;Jb
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try{ v/BMzVi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w|>O!]K]  
output.writeInt(nStartPos.length); &dkjT8L$  
for(int i=0;i<nStartPos.length;i++) \{G1d"n  
{ @iwg`j6ol  
// output.writeLong(nPos); czf|c  
output.writeLong(fileSplitterFetch.nStartPos); gs_nUgcA  
output.writeLong(fileSplitterFetch.nEndPos); }*4K]3et$  
} GJY7vS^#  
output.close(); ?B2 T'}
~  
} it~>)_7*P  
catch(IOException e){e.printStackTrace ();} `}^_>  
catch(Exception e){e.printStackTrace ();} ;$\d^i{N  
} "$tP>PO{<  
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//读取保存的下载信息（文件指针位置） KN;b+`x;M  
private void read_nPos() hYW<4{Gjr  
{ OIa=$l43C  
try{ =kUN ^hb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (!U5B Hnd  
int nCount = input.readInt(); iQ9jt  
nStartPos = new long[nCount]; GyO
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nEndPos = new long[nCount]; Cu0N/hBT  
for(int i=0;i<nStartPos.length;i++) 3!0Eh8ncI  
{ joh=0nk;D  
nStartPos = input.readLong(); <=*xwI&q  
nEndPos = input.readLong(); q*oUd/F8  
} 1B;sSp.>  
input.close(); \*s'S*~  
} H|H!VPof]  
catch(IOException e){e.printStackTrace ();} Z4/rqU  
catch(Exception e){e.printStackTrace ();} 8#w}wGV*  
} yD+)!q"  
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private void processErrorCode(int nErrorCode) HPGi5rU  
{ X
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System.err.println("Error Code : " + nErrorCode); )x-iru A:  
} BOLG#}sm  
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//停止文件下载 O>zM(I+p  
public void siteStop() wY2#xD  
{ WVp7H  
bStop = true; YB h:  
for(int i=0;i<nStartPos.length;i++) )Aa98Eu?2  
fileSplitterFetch.splitterStop(); ,o}!pQ  
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} -bK#&o,  
} xr)Rx{)3h  
//负责部分文件的抓取 t,;1?W#  
**FileSplitterFetch.java zlmb_akJ  
*/ 2yhtJ9/  
package NetFox; >WMH.5p  
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import java.io.*; 5rqjqfFa  
import java.net.*; *s/sF@8<X  
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public class FileSplitterFetch extends Thread { x[3kCa|4A  
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String sURL; //File URL ]BU,*YaB  
long nStartPos; //File Snippet Start Position ik77i?Hg  
long nEndPos; //File Snippet End Position &3mseU  
int nThreadID; //Thread's ID MPMJkL$F
^  
boolean bDownOver = false; //Downing is over .9WJ/RKZ\D  
boolean bStop = false; //Stop identical l tr=_  
FileAccessI fileAccessI = null; //File Access interface KE+y'j#C3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~a8J"W
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{ yOGaW~  
this.sURL = sURL; z

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this.nStartPos = nStart; A+3@N99HeH  
this.nEndPos = nEnd; 6I(y`pJ  
nThreadID = id; Zr_{Z@IpU  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 MI|DOp  
} \BaN?u)a  
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public void run() lNQt  
{ NjVuwIm+  
while(nStartPos < nEndPos && !bStop) 3uCC_Am  
{ 2i#wJ8vrF  
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try{ 2"C'Au  
URL url = new URL(sURL); !SIGzj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |]~tX zY  
httpConnection.setRequestProperty("User-Agent","NetFox"); A"k6n\!n;  
String sProperty = "bytes="+nStartPos+"-"; Aj.TX%}`h  
httpConnection.setRequestProperty("RANGE",sProperty); nI%0u<=d  
Utility.log(sProperty); VcT(n7  
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InputStream input = httpConnection.getInputStream(); V^=z\wBZ  
//logResponseHead(httpConnection); U?d1  
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byte[] b = new byte[1024]; D{h1"q  
int nRead; dC_L~ }=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;Yyg(Ex  
{ Rk56H  
nStartPos += fileAccessI.write(b,0,nRead); [[QrGJr  
//if(nThreadID == 1) _wKFT>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  pzezN  
} g1L$+xD^  
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Utility.log("Thread " + nThreadID + " is over!"); ^<$dTr'  
bDownOver = true; s2iR }<  
//nPos = fileAccessI.write (b,0,nRead); RG[3LX/  
} ~d ~$fR  
catch(Exception e){e.printStackTrace ();} C',D"  
} m>$+sMZE  
} d
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//打印回应的头信息  |X`xJL  
public void logResponseHead(HttpURLConnection con) :
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{ /}r%DND'  
for(int i=1;;i++) \y{Bnp5h  
{ 9M:wUYHT  
String header=con.getHeaderFieldKey(i); T.GY
  
if(header!=null) M5HKRLt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gzvEy^X  
Utility.log(header+" : "+con.getHeaderField(header)); \i}n1Qd  
else P49lE  
break; ~!&WK,k6  
} ]]Ypi=<'  
} aG8}R~wH&  
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public void splitterStop() tfvX0J  
{ 3/>McZ@OH  
bStop = true; ?3kfhR  
} K5z*DYT  
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} 9`i=kp  
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/* hAHl+q)w?  
**FileAccess.java bKYLBu:  
*//文件访问(定位，写) [Oe$E5qv)]  
package NetFox; FEw51a+V  
import java.io.*; 5Jd&3pO  
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public class FileAccessI implements Serializable{ Gn#5zx#l  
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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 4~hd{8  
RandomAccessFile oSavedFile; D)8&v`LS  
long nPos; a9mLPP  
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public FileAccessI() throws IOException \$T  
{ )t9<cJ=  
this("",0); m:d P,  
} 8n?qm96  
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public FileAccessI(String sName,long nPos) throws IOException $GNN*WmHw  
{ ~dC)EG  
oSavedFile = new RandomAccessFile(sName,"rw"); )7Gm<r  
this.nPos = nPos; 3_~V(a
 
oSavedFile.seek(nPos); UGj!I  
} ZK1d3
 
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public synchronized int write(byte[] b,int nStart,int nLen) Jm0P~E[n  
{ 9TBkVbq
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int n = -1; S=~[6;G  
try{ Bab`wfUve  
oSavedFile.write(b,nStart,nLen); Mg W0 ).  
n = nLen; (BEGt'7  
} O&V}T#8n  
catch(IOException e) O;9u1,%w  
{ *?Nrx=O*  
e.printStackTrace (); MzL^u8  
} |)* K#%j  
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return n;  msM  
} "6 |j 0?Q  
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} tisSj?+  
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/* jB!p,fqcb  
**SiteInfoBean.java I;<0v@  
*/ B\r2M`N5  
package NetFox; J:Ea|tXK^  
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public class SiteInfoBean { 7"@^JxYN  
^[,Q2MHCT(  
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private String sSiteURL; //Site's URL KV9'ew+M  
private String sFilePath; //Saved File's Path ,
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private String sFileName; //Saved File's Name F&%@p&  
private int nSplitter; //Count of Splited Downloading File ztTj2M"  
]W~\%`#8?  
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public SiteInfoBean() >!848J  
{//nSplitter的缺省值为5 zsFzF`[k  
//default value of nSplitter is 5 xHq"1Vs=  
this("","","",5); U(P^-J<n1  
} FkY}6  
{^=T&aCYdS  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a$r- U_?  
{ r&oR|-2hRk  
sSiteURL= sURL; .A<G$ db ?  
sFilePath = sPath; /2l&D~d"  
sFileName = sName; k\BJs@-  
this.nSplitter = nSpiltter; EudX^L5U<d  
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} #%N v\g;  
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public String getSSiteURL() fqrQ1{%UH  
{ ?g^42IYG  
return sSiteURL; fI"sdzu^  
} O2;FaASF  
_;
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public void setSSiteURL(String value) :dq.@:+<R  
{ 94VtGg=b}  
sSiteURL = value; V[ju7\>$Z  
} dp
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public String getSFilePath() 7]W6\Z  
{ 8C]K36q  
return sFilePath; *N>n5B2  
} Q2yD4>qy  
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public void setSFilePath(String value) [As9&]Bv5  
{ F-AU'o *  
sFilePath = value; scX'>\w&c  
} #lAC:>s3U  
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public String getSFileName() -p.c8B  
{ ypU-/}Cf,  
return sFileName; dUN{@a\R0  
} ' ` _TFTO  
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public void setSFileName(String value) L$L/5/  
{ yPY}b_W  
sFileName = value; '8%jA$o\g  
} ;)~}/nR<a  
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public int getNSplitter() fi%)5
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{ &1/OwTI4J  
return nSplitter; WC0z'N({W  
} Kb
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public void setNSplitter(int nCount) u7&q(Z&&O  
{ +YZ*>ki  
nSplitter = nCount; F m?j-'  
} b@QCdi,u  
} <fHJ9(5$V  
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/* Cj%n?-
  
**Utility.java ;w/@_!~  
*/ >?<S(  
package NetFox; \SSHjONX  
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public class Utility { Ml_Hq>
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public Utility() yPrF2@#XZ/  
{ Sq&r ;  
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} r[?GO"ej5  
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//线程睡眠 R + ~b@  
public static void sleep(int nSecond) ;b{yu|  
{ SzP`(}AU  
try{ NSawD.9mV  
Thread.sleep(nSecond); 7|5X> yt  
} Ii9[[I  
catch(Exception e) nw4I<Q  
{ <%o9*)F  
e.printStackTrace (); dGyrzuPJ  
} D@2L<!\  
} arIEd VfNa  
Um}f7^fp^l  
//日志 eFh7#~m  
public static void log(String sMsg) 6Hbu7r*tm  
{ g,9&@g/  
System.err.println(sMsg); 3 ,zW6-}  
} M>E~eb/  
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public static void log(int sMsg) w73?E#8  
{ fB80&G9  
System.err.println(sMsg); 6ao~f?JZ  
} aFaioE#h(  
} xa.tH)R  
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/* 0G31Kou  
**TestMethod.java &szYa-K*  
*/ V408uy-M  
package NetFox; ]]0Yh  
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public class TestMethod { ph}%Ay$  
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a^={X<K|/  
public TestMethod() br^ A<@,d  
{ ///xx/weblogic60b2_win.exe 7Db}bDU1 |  
try{ ollsB3]]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
HfZ^ED"}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TjDtNE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'hE'h
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fileFetch.start(); qA;Gl"HF  
} &wAVO_s  
catch(Exception e){e.printStackTrace ();} Kt](|  
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} @DIEENiM  
#dKy{Q3he  
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public static void main(String[] args) $ay!'MK0d  
{ 43x2BW&&  
new TestMethod(); {,i-V57-h  
} "u]&~$  
} %3O))Ug5  
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