http断点续传简单实现（java)

/* GawO>7w8  
**SiteFileFetch.java rx;U/)~#<  
*/ ?hmb"^vlG  
package NetFox; 2"MI8EK  
import java.io.*; i4pJIb  
import java.net.*; 0K2[E^.WN  
:RQ[(zD]  

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public class SiteFileFetch extends Thread { IW1\vfe  
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SiteInfoBean siteInfoBean = null; //文件信息Bean amSyGQ2  
long[] nStartPos; //开始位置 O.E0LCABC  
long[] nEndPos; //结束位置 :I$2[K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >'jM8=o*Ax  
long nFileLength; //文件长度 CS{9|FNz  
boolean bFirst = true; //是否第一次取文件 E+)Go-rS(  
boolean bStop = false; //停止标志 sWC"^ So  
File tmpFile; //文件下载的临时信息 {DK:"ep  
DataOutputStream output; //输出到文件的输出流 >YfOR%mS4  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） U .Od  
public SiteFileFetch(SiteInfoBean bean) throws IOException =_H39)|
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{ { &'TA  
siteInfoBean = bean; @j (jOe  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); PGKXzp'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d0=nAZZ  
if(tmpFile.exists ()) a82mC r  
{ G8s`<:9*  
bFirst = false; #Kl2K4  
read_nPos(); +o3g]0  
} z3C^L  
else ul?BKV+3E  
{ qLP+@wbJ  
nStartPos = new long[bean.getNSplitter()]; asi1c y\  
nEndPos = new long[bean.getNSplitter()]; X]fw9tZ  
} V~_nyjrJM  
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} zEB1Br,  
}j?S?=;m=  
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public void run() ;Wa{q.)  
{ &~%@QC/  
//获得文件长度 N>R%0m<e  
//分割文件 ie(7m|.  
//实例FileSplitterFetch (<l2 ^H  
//启动FileSplitterFetch线程 v'!N

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//等待子线程返回 3+-(;>>\  
try{ Q]wM/7  
if(bFirst) wuzz%9;@B  
{ XNUqZ-M:  
nFileLength = getFileSize(); [&CM-` N  
if(nFileLength == -1) a
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{ hwzUCh 5!  
System.err.println("File Length is not known!"); g#4gGhI  
} +V@=G &Ou0  
else if(nFileLength == -2) ~Z]vr6?$h  
{ VTWE-:r  
System.err.println("File is not access!"); `0i3"06lr  
} )DmiN^:  
else B@]7eVo  
{ `
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for(int i=0;i<nStartPos.length;i++) swlWe}1  
{ ,}tdfkZFYl  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tTGK25&  
} Xa@wN/"F  
for(int i=0;i<nEndPos.length-1;i++) (UF!Zb]{  
{ Gme$FWa  
nEndPos = nStartPos[i+1]; DANSexW  
} GC[{=]}9U  
nEndPos[nEndPos.length-1] = nFileLength; .$0Ob<.  
} m0Syxb  
} u-{l,p_H  
ql~{`qoD~  
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//启动子线程 ;g:bn5G  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :BX{*P  
for(int i=0;i<nStartPos.length;i++) )$B+3f  
{ i)L:VkN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pRvs;klf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;8iL,^.A  
nStartPos,nEndPos,i); ~n^G<iXLp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0f%:OU5Y  
fileSplitterFetch.start(); ;_/q>DR>,3  
} 8 %j{4$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o0G`Xn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Qc;[mxQe  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `4H9f&8(  
nEndPos = " + nFileLength); A_Iu*pz^^  
// fileSplitterFetch[nPos.length-1].start(); 9S%gVNxn  
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8 
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//等待子线程结束 'd^gRH<z  
//int count = 0; 9JV 3  
//是否结束while循环 EQJ_$6
  
boolean breakWhile = false; 0;v~5|r  
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Sz|CreFK16  
while(!bStop) +.]}f}Y  
{ G}#/`]o!K  
write_nPos(); SrtVoe[  
Utility.sleep(500); qW~R-g]  
breakWhile = true; cIvYfgIo9  
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for(int i=0;i<nStartPos.length;i++) Om2X>/V%C  
{ _P<lG[V  
if(!fileSplitterFetch.bDownOver) fG2&/42J  
{ (kQ.tsl  
breakWhile = false; (+LR u1z  
break; qH Ga  
} ^:!(jiH  
} Hu9R.[u  
if(breakWhile) lF8dRIav  
break; o,Zng4NY  
i!W8Q$V  
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//count++; pLQSG}N  
//if(count>4) !mxh]x<e  
// siteStop(); o9LD6$  
} 1O2h9I$bk  
%DRy&k/T  
2^bpH%  
System.err.println("文件下载结束！"); pR6A#DgB  
} '}+X,Usm  
catch(Exception e){e.printStackTrace ();} LAY)">*49H  
} Flujwh@rg  
?>.g;3E$  
9LEilmPs  
//获得文件长度 id tQXwa  
public long getFileSize() te*Y]-&I|/  
{ <,pLW~2-"  
int nFileLength = -1; C6'*/wq  
try{ o`K^Wy~+k#  
URL url = new URL(siteInfoBean.getSSiteURL()); 6eUi
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kE_@5t7O{  
httpConnection.setRequestProperty("User-Agent","NetFox"); HS`bto0*  
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int responseCode=httpConnection.getResponseCode(); %wjB)Mae  
if(responseCode>=400) :uwRuPI  
{ mrhp)yF  
processErrorCode(responseCode); @oz&  
return -2; //-2 represent access is error 22/?JWL>  
} ;WS7.  
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String sHeader; UiK+c30FU  
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for(int i=1;;i++) r$r&4dY  
{ k~jKJb-_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8q~FUJhU  
//Utility.log(in.readLine()); {{]=zt|69  
sHeader=httpConnection.getHeaderFieldKey(i); 0"kE^=  
if(sHeader!=null) QK?2E  
{ ?St=7a(D  
if(sHeader.equals("Content-Length")) 5{ 4"JO3  
{ $uUb$8Bu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); moVa'1ul  
break; siRnH(^J  
} BH#C<0="  
} StyB"1y  
else
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break; l<aqiZSY  
} @r/Id
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} 8XYD L]I'  
catch(IOException e){e.printStackTrace ();} ?BDlB0jxzi  
catch(Exception e){e.printStackTrace ();} XY!{g(  
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Utility.log(nFileLength); 6>=-/)p}  
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return nFileLength;  ?+ -/';  
} FI`nRFq)C  

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//保存下载信息（文件指针位置） %;<k(5bhGJ  
private void write_nPos() J\xz^%p  
{ ycrh5*g  
try{ -Ap2NpZ"t  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^fE\S5P  
output.writeInt(nStartPos.length); @jE d%W  
for(int i=0;i<nStartPos.length;i++) } T/}0W]0  
{ (RDa,
&  
// output.writeLong(nPos); rysP)e  
output.writeLong(fileSplitterFetch.nStartPos); )e|$K= D  
output.writeLong(fileSplitterFetch.nEndPos); k+WO &g*|  
} FtFv<UV  
output.close(); C`NBHRa>  
} V4`:Vci Aw  
catch(IOException e){e.printStackTrace ();} Ms:KM{T0  
catch(Exception e){e.printStackTrace ();} 5w,lw  
} *or2  
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//读取保存的下载信息（文件指针位置） $ ]W[y=  
private void read_nPos() LsJs Q h  
{ d`?U!?Si  
try{ YW?7*go'Z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `W"a!,s2  
int nCount = input.readInt(); K2x
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nStartPos = new long[nCount]; vs\'1^*D  
nEndPos = new long[nCount]; |TB@@ 2Ky&  
for(int i=0;i<nStartPos.length;i++) lBlSNDs  
{ |t4Gz1"q=8  
nStartPos = input.readLong(); Tn4W\?R  
nEndPos = input.readLong(); a1 46kq  
} l~]hGLviJE  
input.close(); [Krm .)  
} P9 {}&z%:  
catch(IOException e){e.printStackTrace ();} Vqa5RVnI  
catch(Exception e){e.printStackTrace ();} pBSq%Hy:  
} BKE\SWu  
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private void processErrorCode(int nErrorCode) w8 ?Pb$Fe  
{ bGZhUEq  
System.err.println("Error Code : " + nErrorCode); C1X}3bB  
} 4ss&'h  
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//停止文件下载 ]> nPqL  
public void siteStop() Ne &Xf  
{ o,?!"*EP  
bStop = true; ]regi- LGU  
for(int i=0;i<nStartPos.length;i++) L
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fileSplitterFetch.splitterStop(); =oo[ Eyr  
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} Z"6 2#VM  
} z$9@j2  
//负责部分文件的抓取 t[]['Iosd  
**FileSplitterFetch.java "%{,T  
*/ Tg"'pO  
package NetFox; ZhhI@_sz  
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import java.io.*; %/UV_@x&  
import java.net.*; [3t0M5x w  

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public class FileSplitterFetch extends Thread { Ef
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String sURL; //File URL y=[gQJ6~r  
long nStartPos; //File Snippet Start Position =LlLE<X"%x  
long nEndPos; //File Snippet End Position FWuw/b$  
int nThreadID; //Thread's ID /Jh1rck  
boolean bDownOver = false; //Downing is over i/NDWVFD  
boolean bStop = false; //Stop identical S:/{  
FileAccessI fileAccessI = null; //File Access interface #,@bxsB  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Oq*n9V  
{ 7#~4{
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this.sURL = sURL; |w=Ec#)t4  
this.nStartPos = nStart; c
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this.nEndPos = nEnd; )D:9R)m  
nThreadID = id; YSqv86  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *,"jF!C&[  
} [dl+:P:zc  
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public void run() ETM2p1ru0  
{ K@q&HV"'.  
while(nStartPos < nEndPos && !bStop) j*tk(o}qG  
{ bsB},pc  
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try{ inYM+o!Ub  
URL url = new URL(sURL); J5O.*&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ID)^vwn  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2$M,*Dnr  
String sProperty = "bytes="+nStartPos+"-"; g.9L)
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httpConnection.setRequestProperty("RANGE",sProperty); DH:J  
Utility.log(sProperty); Takt_N  
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InputStream input = httpConnection.getInputStream(); 5gSylts8  
//logResponseHead(httpConnection); 34z_+  
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byte[] b = new byte[1024]; IrJ+Jov  
int nRead; doBNghS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ski G2n]  
{ 4avc=Y5  
nStartPos += fileAccessI.write(b,0,nRead); :-)GNf yGz  
//if(nThreadID == 1) `AR"!X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I6+2>CUGo  
} gc##V]OD  
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ZT6V/MD7T.  
Utility.log("Thread " + nThreadID + " is over!"); [cDbaq,T  
bDownOver = true; b\:~;  
//nPos = fileAccessI.write (b,0,nRead); ZP-dW|<[x  
} !K[/L< Kv  
catch(Exception e){e.printStackTrace ();} %4,xx'`  
} e8oKn&  
} fe|g3>/|  
>:2}V]/;  
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//打印回应的头信息 h}h^L+4  
public void logResponseHead(HttpURLConnection con) t)} \9^Uo  
{ |=O1Hn  
for(int i=1;;i++) '@bJlJB9>  
{ '99@=3AB:`  
String header=con.getHeaderFieldKey(i); A;,Dg=FL/  
if(header!=null) L?
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); j9:/RJS  
Utility.log(header+" : "+con.getHeaderField(header)); qbb6,DL7J  
else 34z+INkX  
break; X]!D;7^  
} I+|uUg5  
} ]KWK}Zyi  
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public void splitterStop() !4t`Hv?'  
{ vG~+r<:  
bStop = true; B!}BM}r  
} ?eV_ACpZ8  
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} $eBQH  
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/* %G[/H.7s-  
**FileAccess.java F;P5D<  
*//文件访问(定位，写) hU"F;4p  
package NetFox; o\4CoeG  
import java.io.*; BxdX WO  
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public class FileAccessI implements Serializable{ e[{mVhg4E  
89Z#|#uM5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d;=u  
RandomAccessFile oSavedFile; !^iwQ55e2A  
long nPos; _{$fA6C  
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public FileAccessI() throws IOException PNpu*#Z`  
{ I8u!\F  
this("",0); 59<hV?  
} zsVcXBz  
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public FileAccessI(String sName,long nPos) throws IOException OxQYNi2  
{ 6\n?48x}  
oSavedFile = new RandomAccessFile(sName,"rw"); % :/
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this.nPos = nPos;
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oSavedFile.seek(nPos); jO8X:j09A  
} 8KMvAc  
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public synchronized int write(byte[] b,int nStart,int nLen) a9l8{3  
{ 8z}^j
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int n = -1; AbfZ++aJ  
try{ NYB "jKMk  
oSavedFile.write(b,nStart,nLen); . I==-|  
n = nLen; ,h&a9:+i  
} f*m[|0qI<X  
catch(IOException e) /e1(? 20  
{ !D:Jbt@R<n  
e.printStackTrace (); _ym"m,,7?  
} zkexei4^<  
ag8`O&+  
{eQWO
.C{  
return n; GeV+/^u  
} .z-UOyer  
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} x[X`a  
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/* m`}{V5;  
**SiteInfoBean.java xu\eXx6H  
*/ e |V]  
package NetFox; %tmp  
(3;@^S4&w  
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public class SiteInfoBean { ~<)vKk  
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private String sSiteURL; //Site's URL vzXag*0  
private String sFilePath; //Saved File's Path YGk9b+`  
private String sFileName; //Saved File's Name %8r/oS  
private int nSplitter; //Count of Splited Downloading File hXB|g[zT  
pC(sS0J  
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public SiteInfoBean() ~OypE4./1  
{//nSplitter的缺省值为5 >jTp6tu,  
//default value of nSplitter is 5 <9eu1^g  
this("","","",5); RMP9y$~3pU  
} (9C<K<  
Kat&U19YH  
7L3ik;>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;Ii1B{W  
{ _#C()Ro*P  
sSiteURL= sURL; Kq)MTlP0g  
sFilePath = sPath; I#G0, &Gv  
sFileName = sName; Eu,`7iQ?(  
this.nSplitter = nSpiltter; pqR\>d0  
3BQ!qO17^d  
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} yI3kvh  
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public String getSSiteURL() 1^G{tlA-  
{ ,[!LCXp  
return sSiteURL; DjLL|jF  
} L,LNv  
M;.ZM<Ga  
(gXN%rsY  
public void setSSiteURL(String value) Vba.uKNjk  
{ (zcLx;N  
sSiteURL = value; M(Zc^P}N  
} I#rubAl  
_$s> c!t,#  
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public String getSFilePath() D(]E/k@;~  
{ & ,hr8  
return sFilePath; YY5!_k  
} y~ rXl  
`T&jPA9eY  
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public void setSFilePath(String value) wvby?MhPY  
{ z rfUQO  
sFilePath = value; 5h{`<W  
} +-$Ko fnM  
h6D^G5i  
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p  
public String getSFileName() B.dT)@Lx0  
{ ('[TLHP  
return sFileName; kHK0(bYK  
} </`yd2>
 
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public void setSFileName(String value)  jN*:QI  
{ 4JyM7ePND}  
sFileName = value; 8|^CK|m6*  
} 9jir*UI  
Af(WV>'  
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public int getNSplitter() 7^6uG6  
{ K9Hqq7"%  
return nSplitter; /j2H A^GT  
} #q\x$  
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public void setNSplitter(int nCount) }T_Te?<&  
{ p9eRZVy/  
nSplitter = nCount; +-?/e-z")  
} yYZxLJ='  
} x.mrCJn)  
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TFQ!7'xk)  
/* /8'S1!zc  
**Utility.java 5 `/< v^  
*/ rf&M!d}!  
package NetFox; %3r:s`{  
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public class Utility { "Zv~QwC  
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public Utility() nw:-J1kWR  
{ ,E )|y4  
#KlCZ~s  
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} _QOZsEe  
oXsL9,  
//线程睡眠 !^c@shLN4  
public static void sleep(int nSecond) $FTO   
{ m"eteA,"k_  
try{ k(VB+k"3  
Thread.sleep(nSecond); ,5 j"ruZ  
} Q,T"ZdQ  
catch(Exception e) O`1!  
{ w4,Ag{t>  
e.printStackTrace (); o`S?  
} OWq'[T4  
} \c,pEXG  
DL^o
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//日志 "UFs~S|e  
public static void log(String sMsg) 0pb'\lA  
{ m7c*)"^  
System.err.println(sMsg); QF2q^[>w6  
} CTa#Q,  
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public static void log(int sMsg) 5Z/7kU=I  
{ T4/fdORS  
System.err.println(sMsg); SMr13%KN/  
} :nN1e  
} W*DVi_\$y  
=<@2#E)  
!|waK~jK  
/* $lA V6I.  
**TestMethod.java rf:XRJ<4  
*/ VXBY8;+Yp  
package NetFox; pO  Iq%0]  
{@Yb%{+  
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public class TestMethod { IA zZ1#/3  
+gd2|`#  
NH<gU_s8{9  
public TestMethod() ./vZe_o)j$  
{ ///xx/weblogic60b2_win.exe AFvgbn8Qh  
try{ lA(Q@yEW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2zSG&",2D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8F(h*e_?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); C;+(Zp  
fileFetch.start(); @Hb'8F  
} fc=Patg  
catch(Exception e){e.printStackTrace ();} :#E*Y8-  
.{KjEg 6  
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} bu7'oB~:V^  
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public static void main(String[] args) wm{3&m  
{ -ezY=0Q&  
new TestMethod(); B5V_e!*5F*  
} WF&[HKOy/  
} JG[o"&Sd
 
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