http断点续传简单实现（java)

/* XWv;l)  
**SiteFileFetch.java bW^JR,  
*/
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package NetFox; v]X*(e  
import java.io.*; K410.o/=-  
import java.net.*; xvTz|Y  
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public class SiteFileFetch extends Thread { VQ
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SiteInfoBean siteInfoBean = null; //文件信息Bean y87oW_
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long[] nStartPos; //开始位置 /nB|Fo_&Q  
long[] nEndPos; //结束位置 _BHEK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'e:(61_  
long nFileLength; //文件长度 LZ<^b6Dxk  
boolean bFirst = true; //是否第一次取文件 ]oxi~TwY^  
boolean bStop = false; //停止标志 4rrR;V"}  
File tmpFile; //文件下载的临时信息 M*2 Nq=3  
DataOutputStream output; //输出到文件的输出流 (
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） s"B+),Jod  
public SiteFileFetch(SiteInfoBean bean) throws IOException )%vnl~i!  
{ #dDM "s  
siteInfoBean = bean; lGpci  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jH?!\F2)+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ED^0t  
if(tmpFile.exists ()) aDda&RM  
{ 5[Uv%A?H#_  
bFirst = false; \h5!u1{L  
read_nPos(); B/Z-Cpz]  
} D-4{9[  
else 'b:e8m  
{ OZ,Xu&N  
nStartPos = new long[bean.getNSplitter()]; AA<QI'6  
nEndPos = new long[bean.getNSplitter()]; JasA w7  
} \IZY\WU}2  
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} ;b!qt-;.<  
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public void run() i>e?$H,/  
{ %S/?Ci  
//获得文件长度 1P?|.W_^1  
//分割文件 '9!J' [W  
//实例FileSplitterFetch J?C:@Q  
//启动FileSplitterFetch线程 u=t.1eS5  
//等待子线程返回
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try{ ZlP+t>  
if(bFirst) MI)v@_1d  
{ U=PTn(2  
nFileLength = getFileSize(); ^@^K <SVc  
if(nFileLength == -1) `T{'ufI4B  
{ hlmeT9v{  
System.err.println("File Length is not known!"); @MO/LvD  
} ><I{R|bC  
else if(nFileLength == -2) lBGYZ--  
{ )6(|A$~C+  
System.err.println("File is not access!"); 3,-[lG@o  
} 5bBCI\&sam  
else yxAy1P;dX  
{ E
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for(int i=0;i<nStartPos.length;i++) )+|Y;zC9  
{ QD%!a{I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); q _Z+H4  
} </2 aQn  
for(int i=0;i<nEndPos.length-1;i++) -5JN`  
{ ["[v  
nEndPos = nStartPos[i+1]; )]kxLf#  
} Whe-()pG{  
nEndPos[nEndPos.length-1] = nFileLength; p>B-Ubu  
} <Xw\:5 F<7  
}  QJ!2Vw4K  

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//启动子线程 F^81?Fi.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; OrwVRqW-z  
for(int i=0;i<nStartPos.length;i++) nc6PSj X  
{ 8OiCldw:HN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Jv}&8D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 51Vqbtj^  
nStartPos,nEndPos,i); "6 ~5RCZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <w`EU[y_  
fileSplitterFetch.start(); ;cB3D3fR.  
} SP/'4m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -Aojk8tc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y&H<8ez  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +lb&_eD  
nEndPos = " + nFileLength); kc(m.k!|f\  
// fileSplitterFetch[nPos.length-1].start(); hfw+n<  
[+Fajo;0  
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//等待子线程结束 !o1IpTN  
//int count = 0; 83 <CDjD  
//是否结束while循环  TD%&9$F  
boolean breakWhile = false; )Xa_ry7  
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] E:NmBN<  
while(!bStop) @dx8{oQ  
{ U$Z<lx2P  
write_nPos(); 7Mk>`4D'c  
Utility.sleep(500); k7j.VpN9  
breakWhile = true; *jvP4Nz)k  
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for(int i=0;i<nStartPos.length;i++) @yo6w}3+-  
{ 4EmdQn  
if(!fileSplitterFetch.bDownOver) Lq;T\m_de  
{ iD*Hh-  
breakWhile = false; e9HL)=YP  
break; T<"Bb[kH  
} v>j,8E  
} @Pf9;7,TV  
if(breakWhile) *@p"  
break; >lKu[nq;  
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//count++; 0N~kq-6.\  
//if(count>4) ?|98Y"w  
// siteStop(); ul#y'iY]  
} +80bG(I_  
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System.err.println("文件下载结束！"); *5.wwV  
} 1y\bJ  
catch(Exception e){e.printStackTrace ();} @HPr;m!  
} OTE,OCB[  
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h  
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//获得文件长度 zyhM*eM.7  
public long getFileSize() ]
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{ (qvH=VTwP  
int nFileLength = -1; jXLd#6  
try{ T~k@Z  
URL url = new URL(siteInfoBean.getSSiteURL()); U[02$gd0l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TA0(U$ 4  
httpConnection.setRequestProperty("User-Agent","NetFox"); A]TEs)#*7)  
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int responseCode=httpConnection.getResponseCode(); ('7
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if(responseCode>=400) R?{xs  
{ kmX9)TMVO  
processErrorCode(responseCode); 2]Il:>n,  
return -2; //-2 represent access is error &l3(+4Sh  
} ?_d6;  
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String sHeader; _dRB=bl"O  
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for(int i=1;;i++) Jx~H4y=z  
{ jLM([t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); l)*(UZ"  
//Utility.log(in.readLine()); |Q%P4S"B?  
sHeader=httpConnection.getHeaderFieldKey(i); l cHf\~  
if(sHeader!=null) ZnRT$ l O  
{ *Z^`H!&  
if(sHeader.equals("Content-Length"))  5{oc  
{ }oA>0Nw$K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )WbWp4  
break; KILX?Pt[7  
} U 7.kYu  
} tE_n>~Zs  
else ;cvMNU$fN  
break; >5#}/G&  
} bj}Lxc],  
} RrvC}9ar  
catch(IOException e){e.printStackTrace ();} &Ap9h# dK  
catch(Exception e){e.printStackTrace ();} Vy
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Utility.log(nFileLength); E I(e3  
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return nFileLength; +^+'.xQ  
} \c4jGJ  
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//保存下载信息（文件指针位置） ^;<d<V}*  
private void write_nPos() QMz=e  
{ erW2>^My  
try{ V~[b`&F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Gmi?xGn  
output.writeInt(nStartPos.length); J)Y`G4l2@  
for(int i=0;i<nStartPos.length;i++) e)n ,Y  
{ ofV0L
  
// output.writeLong(nPos); $QwpoVp`~  
output.writeLong(fileSplitterFetch.nStartPos); o=_7KWOA  
output.writeLong(fileSplitterFetch.nEndPos); #p@GhI!6  
} '"E!av>  
output.close(); !e$ZOYe  
} T2S_> #."l  
catch(IOException e){e.printStackTrace ();} PXYLLX\3  
catch(Exception e){e.printStackTrace ();} sWte&  
} Z
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//读取保存的下载信息（文件指针位置） ];hqI O#nM  
private void read_nPos() TLVsTM8P  
{ t&?{+?p: 9  
try{ j=irx5:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); sFz0:SqhE  
int nCount = input.readInt(); x C&IR*  
nStartPos = new long[nCount]; Zh;wQCDj  
nEndPos = new long[nCount]; }W8A1-UF  
for(int i=0;i<nStartPos.length;i++) B6 (\1  
{ 0>Snps3*Z  
nStartPos = input.readLong(); .)b<cH~%  
nEndPos = input.readLong(); (cOe*>L;  
} [oVM9Q  
input.close(); Pd~=:4  
} zp;!HP;/=  
catch(IOException e){e.printStackTrace ();} +
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catch(Exception e){e.printStackTrace ();} >-I <`y-H  
} 4T(d9y  
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private void processErrorCode(int nErrorCode) @!fUp b  
{ &]o-ZZX  
System.err.println("Error Code : " + nErrorCode); XQ}J4J~Vm  
} 8C@u+tx  
/S]RP>cQ  
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//停止文件下载 AE}cHBwZE  
public void siteStop() l;_IH|A  
{ ]6^<VC`5D  
bStop = true; {IJ;)<>&VE  
for(int i=0;i<nStartPos.length;i++) "u7[[.P)  
fileSplitterFetch.splitterStop(); GLtd<M"  
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} N9_* {HOy  
} =WT$\KYGv  
//负责部分文件的抓取 L T$U z  
**FileSplitterFetch.java iibG$?(  
*/ cDY)QUmi  
package NetFox; H9(?yI@Zr#  
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import java.io.*; S{;Pga*Px  
import java.net.*; y
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public class FileSplitterFetch extends Thread { <3{MS],<<  
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String sURL; //File URL >NBc-DX^  
long nStartPos; //File Snippet Start Position 'NlhLu  
long nEndPos; //File Snippet End Position [ @eA o>  
int nThreadID; //Thread's ID P0.cF]<m  
boolean bDownOver = false; //Downing is over eZPeyYX  
boolean bStop = false; //Stop identical XG.[C>  
FileAccessI fileAccessI = null; //File Access interface V+"%B
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Rsfb?${0G  
{ M9W zsWM  
this.sURL = sURL; r&E gP  
this.nStartPos = nStart; VhkM{O  
this.nEndPos = nEnd; MT&aH~YB  
nThreadID = id; |X8?B=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [Jt}^  
} >4X2uNbZS  
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public void run() *,$5EN  
{ >8(i;)(3  
while(nStartPos < nEndPos && !bStop) 4]U=Y>\Sr  
{ 754MQK|g  
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try{ 5)%ahmY  
URL url = new URL(sURL); $v@$C
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7{F\b  
httpConnection.setRequestProperty("User-Agent","NetFox"); R!j#  
String sProperty = "bytes="+nStartPos+"-"; $z%(He  
httpConnection.setRequestProperty("RANGE",sProperty); >)ekb7  
Utility.log(sProperty); q~R8<G%YK  
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InputStream input = httpConnection.getInputStream(); uslu-|b!%  
//logResponseHead(httpConnection); "@nH;Xlq  
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byte[] b = new byte[1024]; jhm3:;Z  
int nRead; c#N4XsG,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) lr>NG,N  
{ f(|k0$EIu  
nStartPos += fileAccessI.write(b,0,nRead); d&NnpjH}c  
//if(nThreadID == 1) ynIC (t  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q ]CMm2L^f  
} B"&-) (  
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Utility.log("Thread " + nThreadID + " is over!"); 2&4nf/sE  
bDownOver = true; i=Qy?aU?  
//nPos = fileAccessI.write (b,0,nRead); WEj{2+  
} J 4gtm"2)  
catch(Exception e){e.printStackTrace ();} uy hh"[  
} {^dq7!  
} U4!KO;Jc  
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//打印回应的头信息 0*XsAz1,9  
public void logResponseHead(HttpURLConnection con) "'z}oS  
{ Fe0M2%e;|  
for(int i=1;;i++) *-9i<@|(U^  
{ q2EDrZ  
String header=con.getHeaderFieldKey(i); F=Bdgg9s  
if(header!=null) @Y/&qpo$#W  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2#.s{
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Utility.log(header+" : "+con.getHeaderField(header)); %P0  
else 12Oa_6<\0;  
break; m%[e_eS  
} 1cK'B<5">]  
} XH?//.q  
unFRfec{  
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public void splitterStop() a}%f+`z  
{ sq2:yt  
bStop = true; \\dUp>1=  
} `7=$I~`  
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} <r#FI8P;X  
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/* VgNB^w  
**FileAccess.java L/ 7AGR|;C  
*//文件访问(定位，写) @ual+=L  
package NetFox; yu'-'{%  
import java.io.*; RzqgN*]lY  
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public class FileAccessI implements Serializable{ eNd&
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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 t<UJR*R=L  
RandomAccessFile oSavedFile; V?M(exN  
long nPos; uY.Ns ?8  
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public FileAccessI() throws IOException iO$87!  
{ ~M}{rl.n=  
this("",0); }b\hRy~=r  
} }nlS&gew^  
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public FileAccessI(String sName,long nPos) throws IOException INA3^p'w  
{ F^.A~{&L  
oSavedFile = new RandomAccessFile(sName,"rw"); fbh,V%t7  
this.nPos = nPos; hW#^H5?  
oSavedFile.seek(nPos); -P}A26qB  
} VL*KBJ  
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public synchronized int write(byte[] b,int nStart,int nLen) /JS_gr@DK  
{ S9Sgd&a9  
int n = -1; P PJ^;s  
try{ p^8a<e?f~f  
oSavedFile.write(b,nStart,nLen); xxur4@p!  
n = nLen; 8oJl ]  
} i% 1UUI(W  
catch(IOException e) o-rX4=T  
{ bG]0|  
e.printStackTrace (); 1d< b\P0  
} Rf!v{\  
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return n; (m R)o&Y%,  
} -$:;en?  
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} [OCjYC`  
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/* 86=W}eV1r  
**SiteInfoBean.java ;z4J)qw  
*/ 8'*x88+  
package NetFox; z,aMbgt  
"SMJ:g",  
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public class SiteInfoBean { !Aj}sh{  
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V[(fE=cIN~  
private String sSiteURL; //Site's URL 'W(u.  
private String sFilePath; //Saved File's Path 8m{e,o2.  
private String sFileName; //Saved File's Name ;}E}N:A  
private int nSplitter; //Count of Splited Downloading File NF
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public SiteInfoBean() JN/=x2n.  
{//nSplitter的缺省值为5 UfX~GC;B  
//default value of nSplitter is 5 zcP=+Y)YA  
this("","","",5); c]uieig0~  
} tpGT~Y(  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #%[;vK  
{ Fl_}Auj{&(  
sSiteURL= sURL; fn,n'E]  
sFilePath = sPath; dcY(1p)  
sFileName = sName; D\THe-Vtr  
this.nSplitter = nSpiltter; zpwoK&T+  
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} ,1{qZ(l1  
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public String getSSiteURL() 3
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{ ?+Gt?-! 5q  
return sSiteURL; RxqNgun@  
} )c4tGT<  
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5[4wN( )  
public void setSSiteURL(String value) qHub+"2  
{ -*k2:i`  
sSiteURL = value; `TPIc  
} U\P4ts  
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public String getSFilePath() b,^ "-r  
{ 4z(~)
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return sFilePath; b WNa6x  
} Sh(ys*y>  
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public void setSFilePath(String value) VZt%cq  
{ Wo "s;Z  
sFilePath = value; S' $;  
} CK[8y&  
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3*<@PXpK&  
public String getSFileName() \1Y|$:T/  
{ F- -g?Q^  
return sFileName; D>y5&`  
} @/^<9  
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public void setSFileName(String value) `D(V_WZ  
{ d` ttWWPw  
sFileName = value; h,$CJdDY]  
} %e]G]B%  

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public int getNSplitter() $_F_%m"\  
{ j;`pAN('  
return nSplitter; rci,&>L"  
} av!;k2"
 
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public void setNSplitter(int nCount) \OVFZ D  
{ Z5'^81m$o  
nSplitter = nCount; ~ L4NK#  
} yzK<yvN  
} S9!KI)  
le 
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/* !Wr<T!T  
**Utility.java
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*/ +A?P4}  
package NetFox; Bug.>ln1  
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public class Utility { 82@^vX  
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public Utility() jVnTpa!A  
{ c~tl0XU1  
4 *}H3-`  
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} MJiVFfYW  
ntH`\ )xi  
//线程睡眠 F2 B(PGa7  
public static void sleep(int nSecond) h|]cZMGo  
{ OpaRQ=  
try{ \H .Cmm^I  
Thread.sleep(nSecond); [@9S-$Xa  
} _{`Z?lt  
catch(Exception e) >s5}pkAv|e  
{ =J1V?x=l@  
e.printStackTrace (); pK-tj  
} }ex4dhx2M  
} (W h)Ov"  
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//日志 Q`*U U82!  
public static void log(String sMsg) <5G(Y#s/?  
{ )f$4:Pq  
System.err.println(sMsg); L6CI9C;-b  
} bIGcszWr  
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public static void log(int sMsg) ufk2zL8y  
{ = vqJ0!  
System.err.println(sMsg); b4L7]&  
} !AXLoq$SY  
} >0@w"aKn  
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/*
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**TestMethod.java {v
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*/ ]D;*2Lw4&  
package NetFox; d(|?gN^  
h rSH)LbJ  
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public class TestMethod { /x@aAJ|
 
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0]5XTc3r  
public TestMethod() 'a0M.*f}G  
{ ///xx/weblogic60b2_win.exe ,iYhD-"'  
try{ >rlUV"8jY;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L|WrdT D;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); GcN}I=4|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Lx>[`QT  
fileFetch.start(); +-qk\sQ  
} ez32k[eV!  
catch(Exception e){e.printStackTrace ();} ,oH\rrglf  
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} =7e!'cF[  
33<{1Y[Q6E  
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public static void main(String[] args) |a03SZx  
{ 5{(4%  
new TestMethod(); .+S%hT,v6i  
} sxr,]@  
} d8;kM`U  
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