http断点续传简单实现（java)

/* fLV@~T|  
**SiteFileFetch.java 51'V[tI;8  
*/ SA [(1dy;  
package NetFox; /}s#   
import java.io.*; ryTtGx%a  
import java.net.*; zF&_9VNk=c  
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public class SiteFileFetch extends Thread { !ce,^z&5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean UiZ1$d*  
long[] nStartPos; //开始位置 ##U/Wa3  
long[] nEndPos; //结束位置 h\8bo=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 M*F`s&vM  
long nFileLength; //文件长度 &p=(0$0&-  
boolean bFirst = true; //是否第一次取文件 bWzUWLa  
boolean bStop = false; //停止标志 Hlj3z3  
File tmpFile; //文件下载的临时信息 ^!SwY_>  
DataOutputStream output; //输出到文件的输出流 !1P<A1K  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O! w&3 p  
public SiteFileFetch(SiteInfoBean bean) throws IOException EHt(!;?q  
{ 83Fmu/(  
siteInfoBean = bean; ;5}"2hU>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "=0JYh)%_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); N ^H H&~V  
if(tmpFile.exists ()) weIlWxy  
{ ;zi4W1  
bFirst = false; 2X=*;r"{J  
read_nPos(); MUp{2_RA  
} kk aS&r>  
else J(`(PYo\i  
{ =7zvp,B  
nStartPos = new long[bean.getNSplitter()]; do@BJWo  
nEndPos = new long[bean.getNSplitter()]; <2PO3w?Z  
} 9Oc(Gl5az  
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} T?8N$J  
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public void run() `wLMJ,@f.  
{ ](^BQc  
//获得文件长度 FdmoR;  
//分割文件 ~`VD}{[,B  
//实例FileSplitterFetch 3HB(rTw  
//启动FileSplitterFetch线程 zY\MzhkX,  
//等待子线程返回 M!]g36h[  
try{ O%busM$P)/  
if(bFirst) %2rUJaOgy$  
{ c`!8!R  
nFileLength = getFileSize(); m#t  
if(nFileLength == -1) Kv6#WN~  
{ "\x\P)j0>  
System.err.println("File Length is not known!"); A*+KlhT  
} F$>^pw  
else if(nFileLength == -2) !\N|$-M  
{ 5\P3JoH:Yg  
System.err.println("File is not access!"); di#:KW  
} atjrn:X  
else "%{J$o  
{ Z)H9D(Za  
for(int i=0;i<nStartPos.length;i++) GbbD)  
{ aT%6d@g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }TAHVcX*p  
} # >L^W7^  
for(int i=0;i<nEndPos.length-1;i++) FVS@z5A8<=  
{ +G<9|-  
nEndPos = nStartPos[i+1]; A+1>n^^_<  
} b>"=kN/  
nEndPos[nEndPos.length-1] = nFileLength; 334tg'2]  
} 5_ioJ  
} @mrGG F  
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@+ U++  
//启动子线程 L BP|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U `<?~Bz  
for(int i=0;i<nStartPos.length;i++) +idp1SJ4  
{ l:rT{l=8*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  [EU\-  
nStartPos,nEndPos,i); 8q#Be1u<s2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p-;I"
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fileSplitterFetch.start(); p6e9mSs  
} X[up$<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), QUU'/e2^c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #'jd.'>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1P+Te,I  
nEndPos = " + nFileLength); z^
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// fileSplitterFetch[nPos.length-1].start(); q-)Ynp4'  
8h| 9;%  
)w3HC($g  
//等待子线程结束 8f0Ytfhw  
//int count = 0; EZvf\s>LT  
//是否结束while循环 IrZ!.5%tV  
boolean breakWhile = false; p+>vX X  
zU$S#4/C  
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while(!bStop) =`MU*Arcs[  
{ N}tiaL4  
write_nPos(); ~9KxvQzt  
Utility.sleep(500); Y]R;>E5o|  
breakWhile = true; z1u1%FwOfM  
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)HN,Az"  
for(int i=0;i<nStartPos.length;i++) 56
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{ <(U:v  
if(!fileSplitterFetch.bDownOver) #I(Ho:b  
{ M)1?$'Aq  
breakWhile = false; uqg#(ADy?R  
break; aA5rvP+  
} }L1-2  
} `>mT/Rmb@  
if(breakWhile) hD5G\TR.  
break; rcWr0q  
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//count++; D
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//if(count>4) g}\Yl.  
// siteStop(); ~A5MzrvIO2  
} *mgK^9<  
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vQ/&iAyut  
System.err.println("文件下载结束！"); [aK7v{Wu  
} ' N@1+v=  
catch(Exception e){e.printStackTrace ();} KF#,Q  
} smM*HDK  
vZQ'  
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//获得文件长度 6] ~g*]T  
public long getFileSize() xgi/,Nk '  
{ g`}+K U  
int nFileLength = -1; ,KMt9<  
try{ MU; L7^  
URL url = new URL(siteInfoBean.getSSiteURL()); '7!b#if  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8p?Fql}F[  
httpConnection.setRequestProperty("User-Agent","NetFox"); BmRk|b  
m&H@f:  
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int responseCode=httpConnection.getResponseCode(); "1P>,\Sjg  
if(responseCode>=400) ?~;8Y=O  
{ `(r[BV|h}  
processErrorCode(responseCode); )PRyDC-  
return -2; //-2 represent access is error i 
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} d
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String sHeader; oCBZ9PGkK  
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for(int i=1;;i++) liW0v!jBo  
{ 1CkBfK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q)\~=/Lb  
//Utility.log(in.readLine()); 5$,dpLbL  
sHeader=httpConnection.getHeaderFieldKey(i); t,*hxzD"  
if(sHeader!=null) &TmN^R>  
{ nMK,g>wp  
if(sHeader.equals("Content-Length")) uY,(3x  
{ f\W1u#;u)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _E[zYSo`  
break; Pa.D+  
} K5O#BBX=  
} t;7 tuq   
else n+Ia@$|m  
break; ,\y)k}0lH  
} }1ABrbc  
} a9CY,+z5B  
catch(IOException e){e.printStackTrace ();} c~B[<.Qj  
catch(Exception e){e.printStackTrace ();} i
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Utility.log(nFileLength); /bE=]nM  
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return nFileLength; Y)kO"  
} +Ar=89  
$ e<&7  
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//保存下载信息（文件指针位置） S&y(A0M  
private void write_nPos() A.aUWh  
{ ;naD`([  
try{ 0ZY.~b'eu  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s2-`}LL  
output.writeInt(nStartPos.length); yQA6w%  
for(int i=0;i<nStartPos.length;i++) eyq8wQT  
{ y\]~S2}G  
// output.writeLong(nPos); K !&{k94  
output.writeLong(fileSplitterFetch.nStartPos); F]e]  
output.writeLong(fileSplitterFetch.nEndPos); /&g5f4[|p  
} fiuF!<#;6  
output.close(); ys+ AY^/  
} E
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catch(IOException e){e.printStackTrace ();} `N8?F3>
 
catch(Exception e){e.printStackTrace ();} s8,{8k  
} U$;FOl  
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//读取保存的下载信息（文件指针位置） l+e L:C!  
private void read_nPos() a2l\B~n  
{ 8!a6)Zeux  
try{ F9DY\EI  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [D[&aA  
int nCount = input.readInt(); qJY'"_Q{  
nStartPos = new long[nCount]; MdzG2uZT  
nEndPos = new long[nCount]; CAGaZ rx  
for(int i=0;i<nStartPos.length;i++) 739J] M  
{ %1E:rw@
 
nStartPos = input.readLong(); OGgP
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nEndPos = input.readLong(); 'Xl[ y  
} 1 J3h_z6/  
input.close(); rFY% fo  
} qA4w*{JN  
catch(IOException e){e.printStackTrace ();} W0vdU;?%  
catch(Exception e){e.printStackTrace ();} ^a=,,6T  
} ^rz8c+ly  
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private void processErrorCode(int nErrorCode) 2
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{ i3T]<&+j5  
System.err.println("Error Code : " + nErrorCode); Im9^mVe  
} J1
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//停止文件下载 tvH{[e$  
public void siteStop() CO25  
{ &"vh=Z-  
bStop = true; &5Ai&<q"p  
for(int i=0;i<nStartPos.length;i++) n@9*>DU  
fileSplitterFetch.splitterStop(); k_)H$*  
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} O=wA/T=w?  
} L_Q1:nL-0  
//负责部分文件的抓取 KF' $D:\  
**FileSplitterFetch.java !C&
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*/ KsZXdM/  
package NetFox; @pueM+(L&  
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import java.io.*; 8 Zy`Z   
import java.net.*; ]ee%=+'  
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public class FileSplitterFetch extends Thread { _9!_fIY  
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String sURL; //File URL HhfuHZ<  
long nStartPos; //File Snippet Start Position ;74hOHDS  
long nEndPos; //File Snippet End Position C!N&uNp@s  
int nThreadID; //Thread's ID ]m0MbA  
boolean bDownOver = false; //Downing is over >SA?lG8f%  
boolean bStop = false; //Stop identical 9N^&~O|1  
FileAccessI fileAccessI = null; //File Access interface K9Dxb  
q|)
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )2T1g~8  
{ p#HbN#^Hy  
this.sURL = sURL; ],vUW#6$N  
this.nStartPos = nStart; N=hr%{}c  
this.nEndPos = nEnd; FT'_{e!M  
nThreadID = id; e6n1/TtqM  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~qe9U 0  
} (as'(+B  
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public void run() j.
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{ b'Cy!dr  
while(nStartPos < nEndPos && !bStop) .`4N#EjP  
{ y
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try{ .sNUU 3xSC  
URL url = new URL(sURL); 0&$+ CWSM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zh7#[#>t  
httpConnection.setRequestProperty("User-Agent","NetFox"); yU"lW{H@  
String sProperty = "bytes="+nStartPos+"-"; r:.5O F}  
httpConnection.setRequestProperty("RANGE",sProperty); fF!Mmm"  
Utility.log(sProperty);  R~u0!  
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InputStream input = httpConnection.getInputStream(); is&A_C7yg  
//logResponseHead(httpConnection); z7V74hRPX  
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byte[] b = new byte[1024]; O[[:3!6q  
int nRead; h_6QVab@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #iD5& klo\  
{ UKyOkuY:w  
nStartPos += fileAccessI.write(b,0,nRead); =&?}qa(P  
//if(nThreadID == 1) <-uE pF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V#jFjObTN  
} {'dpRq{c|  
|aef$f5  
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Utility.log("Thread " + nThreadID + " is over!"); 9Mo(3M  
bDownOver = true; 'T@K$xL8  
//nPos = fileAccessI.write (b,0,nRead); t{t*.{w  
} B6r~4=w_  
catch(Exception e){e.printStackTrace ();} NikY0=i  
} !f\,xa|M  
} %Y8#I3jVJ  
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//打印回应的头信息 @2Xw17[f35  
public void logResponseHead(HttpURLConnection con) Wj2]1A  
{ Z\8TpwD2  
for(int i=1;;i++) -E~pCN(E  
{ 5`,qKJ
  
String header=con.getHeaderFieldKey(i); $7~k#_#PC  
if(header!=null) *44^M{ti<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3Gi#WV4$  
Utility.log(header+" : "+con.getHeaderField(header)); vtw{ A}  
else @f442@_4  
break; ]CyWL6z  
} s>d@=P>R  
} 4L#q?]$  
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public void splitterStop() FyYD7E  
{ :9H=D^J  
bStop = true; G]5m@;~l5  
} y BF3Lms  
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} .Ymoh>JRL  
nxH=Ut7{  
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/* dr3
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**FileAccess.java Zh.5\&bm  
*//文件访问(定位，写) IB#L5yN r  
package NetFox; >?K@zsv}  
import java.io.*; eqD|3Y
X  
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public class FileAccessI implements Serializable{ ; V)pXLE  
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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_1(Ex  
RandomAccessFile oSavedFile; gj{2"tE  
long nPos; MKIX(r(|  
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public FileAccessI() throws IOException ~bU!4P}4j  
{ Vg9nb  
this("",0); ~/LO @  
} z0[_5Cm/  
i
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public FileAccessI(String sName,long nPos) throws IOException 5,  
{ ?K]Cs&E4  
oSavedFile = new RandomAccessFile(sName,"rw"); k?-GI[@X  
this.nPos = nPos; WK;X6`  
oSavedFile.seek(nPos); ?v8.3EE1\o  
} nojJGeW%  
4D(5WJ&  
!p$z8~  
public synchronized int write(byte[] b,int nStart,int nLen) \q9wo*A  
{ Y'tPD#|r  
int n = -1; {&Kck>C'  
try{ A/eZnsk  
oSavedFile.write(b,nStart,nLen); 07pASZ;~  
n = nLen; ( <~  
} *`.h8gTD,  
catch(IOException e) 67Z@Hg  
{ 5~GHAi  
e.printStackTrace (); #6O<!{PH6  
} akg$vHhK4  
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return n; R5PXX&Q  
} t[$C r;  
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} c:QZ(8d]L  

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/*
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**SiteInfoBean.java _XLGX
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*/ J^t-pU  
package NetFox; UQZ<sp4v;  
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public class SiteInfoBean { s|*0cK!K^  
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private String sSiteURL; //Site's URL GQ=Zp3[  
private String sFilePath; //Saved File's Path OCR`1  
private String sFileName; //Saved File's Name ~<[$.8*  
private int nSplitter; //Count of Splited Downloading File )F_0('=t  
@ol}~&"  
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public SiteInfoBean() o< )"\f/,  
{//nSplitter的缺省值为5 @PH`Wn#S  
//default value of nSplitter is 5 p5RnFe
l  
this("","","",5); *4]u?R  
} KZ8Hp=s  
3<Qe'd ^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c3S}(8g5.  
{ Tp vq5Cz  
sSiteURL= sURL; K&T[F!  
sFilePath = sPath; wm1`<r^M.  
sFileName = sName; *`D}voU  
this.nSplitter = nSpiltter; IXjFK  
)\nKr;4MH  
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} {J#SpG 7  
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public String getSSiteURL() "==fWf  
{ =rL%P~0wq  
return sSiteURL; W4MU^``   
} `<Ry_}V  
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public void setSSiteURL(String value) c5 ^CWk K  
{ FM{^ND9x  
sSiteURL = value; AvP$>Alc  
} 3C[#_&_l  
~PaEhj&8  
/\7E&n:)2  
public String getSFilePath() IKaa=r~  
{ Ry47Fze  
return sFilePath; 
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} Jcy{ ~>@7  
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public void setSFilePath(String value) g&E3Wc  
{ I 68Y4s  
sFilePath = value; :mYVHLmea  
} c{"=p8F_  
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oz.#+t%X$b  
public String getSFileName() #uRj9|E7  
{
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return sFileName; L0lqm0h  
} ( *&E~g  
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public void setSFileName(String value) .z+S@s[O  
{ -eE r|Gs)  
sFileName = value; .}n-N #  
} 19h@fA[:  
#gq!L  
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public int getNSplitter()
{>v5~G  
{ gT-"=AsxZQ  
return nSplitter; \iP=V3  
} 8-||Nh  
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public void setNSplitter(int nCount) `erKHZ]S  
{ C@o8C%o  
nSplitter = nCount; #Sc9&DfX  
} o=]\Jy  
} MlKSjKl" !  
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#ETy#jKL  
/* E4QLXx6Wa&  
**Utility.java y2`},  
*/ .QvH7  
package NetFox; @
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public class Utility { ;T\+TZtI  
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public Utility() /R(]hmW  
{ xYd]|y  
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xqQLri}  
} iJU=98q  
H`bS::JI-  
//线程睡眠 ?hmuAgOtbh  
public static void sleep(int nSecond) 8wEUly  
{ XN&cM,   
try{ +\R__tx;  
Thread.sleep(nSecond); ]N;\AXZ7  
} |[_%zV;p>v  
catch(Exception e) %,UTFuM`  
{ 11iV{ h  
e.printStackTrace (); Y*QoD9<T?;  
} wgUgNwd1  
} kNd(KQ<.17  
po!bRk[4  
//日志 Zmc"  
public static void log(String sMsg) 3\ {?L  
{ O=5q<7PM.  
System.err.println(sMsg); ;#?G2AAv  
} /O}lSXo
6E  
Q?2GwN  
)^`V{iD  
public static void log(int sMsg) -pHUC't  
{ JJHO E{%  
System.err.println(sMsg); %"Ia]0  
} /.WIED}>  
} UOpSH{N  
zRMz8IC.  
7J;\&q'  
/* <Uy $b4h  
**TestMethod.java vW-o%u*  
*/ 7?;ZE:  
package NetFox; M`&78j  
Z*+y?5+L"P  
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public class TestMethod { #p<(2wN  
=pBr_pGz=  
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public TestMethod() TQtH
U6  
{ ///xx/weblogic60b2_win.exe {DD #&B  
try{ P(.XB`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); vaLP_V  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); B7wzF"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `MHixQ;j  
fileFetch.start(); )3WUyD*UZN  
} #^}s1 4n  
catch(Exception e){e.printStackTrace ();} )KY4BBc  
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5,pEJ>dDD3  
} Z*b$&nM  
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public static void main(String[] args) $:yIe.F  
{ F1S0C>N?5  
new TestMethod(); Nt;1&dwUb  
} B@@tKn_CQ  
} >@h#'[z,d  
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