http断点续传简单实现（java)

/* 9
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**SiteFileFetch.java (OL4Ex']  
*/ MK~8}x2K  
package NetFox; $6 9&O  
import java.io.*; . iI  
import java.net.*; wo/\]5  
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public class SiteFileFetch extends Thread {  `25yE/  
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SiteInfoBean siteInfoBean = null; //文件信息Bean pa3{8x{9m  
long[] nStartPos; //开始位置
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long[] nEndPos; //结束位置 7U"g3a)=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 itP,\k7>d  
long nFileLength; //文件长度 *#|&JIEsi  
boolean bFirst = true; //是否第一次取文件 _8J.fT$${  
boolean bStop = false; //停止标志 p38-l'{#  
File tmpFile; //文件下载的临时信息 !;{7-
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DataOutputStream output; //输出到文件的输出流 HM1Fz\Sf  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :\c ^*K(9  
public SiteFileFetch(SiteInfoBean bean) throws IOException ie95rZp  
{ iHf$  
siteInfoBean = bean; &h)yro  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SHgN~Um  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4l'fCZhA}  
if(tmpFile.exists ()) +GN(Ug'R  
{ ]Q1yNtN  
bFirst = false; _6hQ %hv8  
read_nPos(); F~W6Bp^W  
} ueWEc^_>  
else 3(N$nsi  
{ NwvC[4  
nStartPos = new long[bean.getNSplitter()]; ,/2Vt/lt  
nEndPos = new long[bean.getNSplitter()]; xm~`7~nFR  
} An0|[uWH  
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} G>}255qY  
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public void run() :eCwY  
{ JyK3{wYS  
//获得文件长度 3;9^  
//分割文件 cqkV9f8Ro  
//实例FileSplitterFetch V2EUW!gn 2  
//启动FileSplitterFetch线程 !9e=_mY  
//等待子线程返回 ~G&dqw/.-U  
try{ `
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if(bFirst) %aCqi(.7  
{ ^z*t%<@[Q  
nFileLength = getFileSize(); Wvh#:Z  
if(nFileLength == -1) _4~+{l+  
{ Q3~H{)[Kq  
System.err.println("File Length is not known!"); a58H9w"u)  
} fTec  
else if(nFileLength == -2) 9W5lSX#^;  
{ ;H*T^0  
System.err.println("File is not access!"); ,ZNq,$j  
} ;igIZ$&  
else "HIRTE;&  
{ sll\g  
for(int i=0;i<nStartPos.length;i++) PFjL1=7I  
{ 9$
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); qe#tj/aZ  
} 0[(8  
for(int i=0;i<nEndPos.length-1;i++) ? OM!+O  
{ 1CZgb  
nEndPos = nStartPos[i+1]; <'oQ \eB  
} PC8Q"O  
nEndPos[nEndPos.length-1] = nFileLength; F)QDJE0  
} ]_gU#,8  
} q3!bky\  
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//启动子线程  mq.`X:e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C<tl/NC  
for(int i=0;i<nStartPos.length;i++) CAhXQ7w'Z  
{ gr2U6gi  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FW4<5~'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wwZ,;\  
nStartPos,nEndPos,i); $s:aW^k  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \M^bD4';>  
fileSplitterFetch.start(); Qw*|qGvy^  
} 4+8@`f>s  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f$$/H>MJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "KpGlY?^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H7n>Vx:L-  
nEndPos = " + nFileLength); Q)h(nbbVak  
// fileSplitterFetch[nPos.length-1].start(); C1)!f j=  
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1))8 A@,  
//等待子线程结束 oG\Vxg*  
//int count = 0; H1./x6Hr  
//是否结束while循环 S=5o < 1  
boolean breakWhile = false; lL3U8}vn  
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while(!bStop) d$!RZHo10V  
{ V 5mTP'  
write_nPos(); g) jYFfGfH  
Utility.sleep(500); V)25$aKW7  
breakWhile = true; }Sv:`9=  
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for(int i=0;i<nStartPos.length;i++) 0GeTSFj  
{ usF.bkTp  
if(!fileSplitterFetch.bDownOver) TC*g|d @b  
{ #*
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breakWhile = false; 3s#N2X;Bc  
break; y<Ot)fa$  
} ~c `l@:  
} 57c8xk[.2  
if(breakWhile) UCjld  
break; g($2Dk_F2  
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//count++; YOO+R{4(  
//if(count>4) ?e 4/p  
// siteStop(); 5\nAeP  
} 7kEn \
 
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System.err.println("文件下载结束！"); rey!{3U  
} b>ySv  
catch(Exception e){e.printStackTrace ();} $!t4r  
} =Xr.'(U  
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//获得文件长度 s$j,9uRr  
public long getFileSize() WNtW|IV  
{ ww1[rCh\+  
int nFileLength = -1; lThB2/tV\  
try{ [7y]n;Fy  
URL url = new URL(siteInfoBean.getSSiteURL()); 8":Q)9;%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O=7CMbS3  
httpConnection.setRequestProperty("User-Agent","NetFox"); |sE'XT4ag  
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int responseCode=httpConnection.getResponseCode(); tCt#%7J;a  
if(responseCode>=400) eaU  
{ Nh44]*  
processErrorCode(responseCode); ?:0Jav  
return -2; //-2 represent access is error (tW`=]z-<  
} BI@[\aRLQ  
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String sHeader; 8}:nGK|kx  
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for(int i=1;;i++) ]`WJOx4  
{ 1'8YkhQ2a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Nh+H9  
//Utility.log(in.readLine()); 5z)~\;[ -  
sHeader=httpConnection.getHeaderFieldKey(i); }Q+|W=2t  
if(sHeader!=null) N;%6:I./  
{ F#E3q|Q"BS  
if(sHeader.equals("Content-Length")) @=u3ZVD  
{ JucY[`|JV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); y@yD5$/  
break; 8&dF  
} <#4h}_xA%  
} HZZn'u  
else #/37V2E  
break; $*m-R*kt  
} F!K>Kz  
} Tid aa  
catch(IOException e){e.printStackTrace ();} _aeBauD  
catch(Exception e){e.printStackTrace ();} BZ^}J!Q'*  
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Utility.log(nFileLength); K*dCc}:`  
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return nFileLength; >yDZ
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} />>\IR  
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//保存下载信息（文件指针位置） q5S9C%b  
private void write_nPos() q@2siI~W  
{ pfI&E#:5  
try{ /Z4et'Lo  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Dvln/SBk  
output.writeInt(nStartPos.length);  !}$$:  
for(int i=0;i<nStartPos.length;i++) TD_Oo-+\  
{ *Pg2c(Vg  
// output.writeLong(nPos); hE-M$LmN@  
output.writeLong(fileSplitterFetch.nStartPos); /qw.p#  
output.writeLong(fileSplitterFetch.nEndPos);
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} 1h5 Akq  
output.close(); vZ Lf  
} }(u ol  
catch(IOException e){e.printStackTrace ();} e96k{C`j0  
catch(Exception e){e.printStackTrace ();} &cTU sK  
} FVBYo%Ap  
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//读取保存的下载信息（文件指针位置） v &+R^iLE  
private void read_nPos() i}?>g-(  
{ QmIBaMI#  
try{ Z?z.?ar  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ? =+WRjF  
int nCount = input.readInt(); E_LN]v  
nStartPos = new long[nCount]; I2Yz#V<%ru  
nEndPos = new long[nCount]; Z/J y'$x  
for(int i=0;i<nStartPos.length;i++) dgePPhj  
{ T[A69O]v  
nStartPos = input.readLong(); Ga'swP=hf  
nEndPos = input.readLong(); <9 ;!3xG  
} {l>hMxij  
input.close(); jZ; =so  
} Y6d@h? ht  
catch(IOException e){e.printStackTrace ();} qIqM{#' ^  
catch(Exception e){e.printStackTrace ();} a.6(K  
} @=kSo -SX  
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private void processErrorCode(int nErrorCode) DlNX 3  
{ |^H5^k "Bv  
System.err.println("Error Code : " + nErrorCode); _J[P[(ab  
} xkR0  
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//停止文件下载 8dyg1F  
public void siteStop() wlmRe`R  
{ {]|J5Dgfe  
bStop = true; 0
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for(int i=0;i<nStartPos.length;i++) dcT80sOC  
fileSplitterFetch.splitterStop(); */DO ex"y  
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} ?G&ikxl  
} c[Zje7 @  
//负责部分文件的抓取 %u5]>]M+  
**FileSplitterFetch.java ^G-@06/!  
*/ dC4'{n|7  
package NetFox; y*h<MQ  
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import java.io.*; @xZR9Z8]L  
import java.net.*; RCLeA=/N@0  
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public class FileSplitterFetch extends Thread { 61 ~upQaR  
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String sURL; //File URL RzusNS  
long nStartPos; //File Snippet Start Position $u6 3]rypm  
long nEndPos; //File Snippet End Position H 7 ^/q7  
int nThreadID; //Thread's ID ~<x:q6  
boolean bDownOver = false; //Downing is over y18Y:)DkL  
boolean bStop = false; //Stop identical 6\S~P/PkE  
FileAccessI fileAccessI = null; //File Access interface Pr,q*_Yy  
*HB-QIl  
/,Jqmm#s^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3DG_QVg^v  
{ .w,q0<}  
this.sURL = sURL; ?[>3QE  
this.nStartPos = nStart; 9Lfv^V0  
this.nEndPos = nEnd; 5nVt[Puw  
nThreadID = id; /vb`H>P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 IdxzE_@  
} W'TaBuCb  
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public void run() ;IM}|2zuN  
{ HLHz2-lI  
while(nStartPos < nEndPos && !bStop) qb` \)X]9  
{
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try{ ,wdD8ZT'Ip  
URL url = new URL(sURL); hwNf~3eJk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h3@v+Z<}  
httpConnection.setRequestProperty("User-Agent","NetFox"); t<?,F  
String sProperty = "bytes="+nStartPos+"-"; Y:)e(c"A  
httpConnection.setRequestProperty("RANGE",sProperty); B^jc3 VsR  
Utility.log(sProperty); fa2kG&, _  
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InputStream input = httpConnection.getInputStream(); "8zDbdK  
//logResponseHead(httpConnection); ^L&iR0  
, SnSW-P  
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byte[] b = new byte[1024]; 63x?MY6  
int nRead; t5IEQ2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i
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{ '(jG[ry&T  
nStartPos += fileAccessI.write(b,0,nRead); [;myHI`tw  
//if(nThreadID == 1) QnX(V[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %C_HXr@  
} ',5ky{  
=zs`#-^8  
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Utility.log("Thread " + nThreadID + " is over!"); 57'4ljvYi  
bDownOver = true; 2jCfT>`3  
//nPos = fileAccessI.write (b,0,nRead);
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} yyy|Pw4:Z  
catch(Exception e){e.printStackTrace ();} PRE|+=w$  
} 6Sn.I1Wy  
} QUQ'3  
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//打印回应的头信息 # c^z&0B}  
public void logResponseHead(HttpURLConnection con) WvZ8/T'x  
{ }|5Pr(I  
for(int i=1;;i++) c_!cv":s  
{ 4#hSJ(~7S  
String header=con.getHeaderFieldKey(i); gt w Q-  
if(header!=null) )B8$<sv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r^ ZEImjc  
Utility.log(header+" : "+con.getHeaderField(header)); lBGQEP3;  
else K8Y=S12Ti  
break; uOdl*|T?  
} c<$OA=n  
} EI^C{$Y  
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public void splitterStop() Uq`'}Vo  
{ >Wg hn:^  
bStop = true; ls)%
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} {h`uV/5@`  
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} 1|-Dj|  
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/* 3I-MdApT  
**FileAccess.java q;)JISf.  
*//文件访问(定位，写) 0v$~90)  
package NetFox; $z*'fXg  
import java.io.*; T0rGM  
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public class FileAccessI implements Serializable{ _b;{_g  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 N_[*H  
RandomAccessFile oSavedFile; xe&i^+i  
long nPos; 3WIk  
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public FileAccessI() throws IOException 3n}?bY8@5_  
{ yd
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this("",0); 'u<juFr  
} RQu(Wu|m.  
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public FileAccessI(String sName,long nPos) throws IOException 3 xp)a%=7  
{ !H>R%g#28_  
oSavedFile = new RandomAccessFile(sName,"rw"); M?uC%x+S$_  
this.nPos = nPos; xAMW-eF?d  
oSavedFile.seek(nPos); AX
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} w!clI8v/  
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public synchronized int write(byte[] b,int nStart,int nLen) w%BL  
{ M}v/tRI  
int n = -1; Dy8r 9  
try{ cY.bO/&l  
oSavedFile.write(b,nStart,nLen); ><HE;cVg?  
n = nLen; l}sjD[2  
} K1!j fp  
catch(IOException e) ax5<#3__  
{ ur7q [n  
e.printStackTrace (); G?/DrnK:  
}
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return n; 9.B KI/  
} oc0G|  
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} qE3UO<FA  
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/* P:]^rke~&  
**SiteInfoBean.java j*TYoH1  
*/ __GqQUQ  
package NetFox; VUR|OV%  
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i|*)I:SHU  
public class SiteInfoBean { 'o>B'$  
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private String sSiteURL; //Site's URL @eIJ]p  
private String sFilePath; //Saved File's Path r/6o \-  
private String sFileName; //Saved File's Name _#8RSr8'y  
private int nSplitter; //Count of Splited Downloading File Ur=(.%@  
eu|;eP-+d  
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public SiteInfoBean() !.(P~j][  
{//nSplitter的缺省值为5 T&o(N3lW  
//default value of nSplitter is 5 G.dTvLv  
this("","","",5); Ob`d  
} !AfHk|  
@;?p&.W`D  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |kV*Jc k  
{ 3r."j2$Hs0  
sSiteURL= sURL; zz4N5["  
sFilePath = sPath; ktBj|-'>  
sFileName = sName; ZO$m["|  
this.nSplitter = nSpiltter; v+#}rUTF  
7f!YoW;1  
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} V"G*N<q  
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public String getSSiteURL() E+g@M8D  
{ E3gh?6  
return sSiteURL; Tl
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} 9}F*P669f  
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public void setSSiteURL(String value) Rww{:R  
{ w\i\Wp,FP  
sSiteURL = value; (w/T-*  
} Xe:jAkDp  
B s#hr3h-  
.|b$NM  
public String getSFilePath() K<ft2anY5  
{ +kO!Xc%P&  
return sFilePath; l@+7:n4K0  
} JJ2_hVU  
:hFIl0$,"3  
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public void setSFilePath(String value) [b>Fn%y  
{ >A"v ed8  
sFilePath = value; DiwxXqY  
} \T:i{.i  
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public String getSFileName() z(Pe,zES  
{ .e=:RkI,  
return sFileName; ADP%QTdqFJ  
} L`p4->C9A  
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public void setSFileName(String value) vMt/u?oB  
{ [~#WG/!:  
sFileName = value; _R13f@NWB:  
} Y^7
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public int getNSplitter() s!&#c`=  
{ p&bROuw<T  
return nSplitter; pg.ri64H<  
} UT=tT)4b  
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public void setNSplitter(int nCount) ,p2s:&"  
{ !K}~/9Z=m  
nSplitter = nCount; (ehK?6[  
} `W:%mJd9  
} ?:8ido#-  
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/* ;q:zT\A  
**Utility.java $M lW4&a|  
*/ dWUm\t'#  
package NetFox; "UGY2skf;  
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public class Utility { w' OXlR
 
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public Utility() g-HN  
{ P+PR<ZoI{f  
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} ;"fDUY|  
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//线程睡眠 Hl/ QnI!  
public static void sleep(int nSecond) 9XyYHi  
{ P'*)\faw  
try{ V=qwwYz~  
Thread.sleep(nSecond); K[Kh&`T  
} &7b|4a8B%  
catch(Exception e) TI#''XCB5  
{ !\i\}feb  
e.printStackTrace (); {7;8#.S72  
} UXugRk%d  
} V_RTI.3p  
E4W -hq~  
//日志 2FF4W54I  
public static void log(String sMsg) 8:>1F,  
{ OjF_ %5  
System.err.println(sMsg); Ib\iT:AJ  
} 9
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3'qJ/*]9  
public static void log(int sMsg) g[Ib,la_a  
{ an
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System.err.println(sMsg); Xr2ou5zAn  
} .DR<Te  
} %K`% *D
  
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/* Vf'd*-_!Q<  
**TestMethod.java ? glSC$b  
*/ IOoz^/'  
package NetFox; j!4et;  
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public class TestMethod { \ 3?LqJ  
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public TestMethod() YZ7|K<   
{ ///xx/weblogic60b2_win.exe 8` @G;o  
try{ W4e5Rb4~f"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ryCI>vJz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Y$Y_fjd_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &)vC;$vD`  
fileFetch.start(); jhu&&==\f  
} CkD#/  
catch(Exception e){e.printStackTrace ();} ;SaX;!`39+  
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} ?jt}*q>X]  
T G{k0cdOT  
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public static void main(String[] args) Yd=a}T  
{ 9^Whg~{  
new TestMethod(); >teOm?@U  
} \ZhfgE8{%  
} A
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