http断点续传简单实现（java)

/* F9 r5 Z  
**SiteFileFetch.java "z{/*uM2<  
*/ @P7'MiP]K  
package NetFox; (%X *b.n=  
import java.io.*; 1kvX#h&V  
import java.net.*; FOQ-KP\=,  
)/jDt dI  
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public class SiteFileFetch extends Thread { K=N&kda  
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SiteInfoBean siteInfoBean = null; //文件信息Bean y|| n9  
long[] nStartPos; //开始位置 9i\RdJv.  
long[] nEndPos; //结束位置 R4
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 3+Lwtb}XPF  
long nFileLength; //文件长度 Gd 4S7JE  
boolean bFirst = true; //是否第一次取文件 ;\7`G!q  
boolean bStop = false; //停止标志 I6^y` 2X  
File tmpFile; //文件下载的临时信息 k*C69  
DataOutputStream output; //输出到文件的输出流 l$gJ^Wf2gY  
4;6"I2;zfG  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =3035{
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public SiteFileFetch(SiteInfoBean bean) throws IOException nX (bVT4i  
{ }k VC]+  
siteInfoBean = bean; }dN\bb{#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); j\>&]0-Iq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ".>#Qp%  
if(tmpFile.exists ()) BQ6$T&  
{ u&l;\w  
bFirst = false; `,V&@}&"n  
read_nPos(); }ppApJT  
} jWUrw  
else 9K&$8aD  
{ 8'Q+%{?1t  
nStartPos = new long[bean.getNSplitter()]; XZOBK^,5^B  
nEndPos = new long[bean.getNSplitter()]; C1;uAw?\  
} <9]"p2  
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} `:iMGqZN  
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public void run() <sC(a7i1  
{ fQ9af)d  
//获得文件长度 NuO@Nr  
//分割文件 DNmC   
//实例FileSplitterFetch oc"p5Y3,Os  
//启动FileSplitterFetch线程 Zna6-0o  
//等待子线程返回 tV=Qt[|@  
try{ ?*~ ~O
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if(bFirst) | d*<4-:  
{ $(62j0mS>  
nFileLength = getFileSize(); a0ms9%Y;Q[  
if(nFileLength == -1) pss')YP.  
{ :7(fBf5  
System.err.println("File Length is not known!"); Sqp9
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} d[h=<?E5  
else if(nFileLength == -2) efyEzL  
{ ;ab[YMkH  
System.err.println("File is not access!"); 5
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} j/Kul}Ml\*  
else #sU>L=  
{ k x:+mF  
for(int i=0;i<nStartPos.length;i++) 8;qOsV)UDT  
{ Oyb9 ql^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NkUY_rKPb  
} F42^Uoaz  
for(int i=0;i<nEndPos.length-1;i++) !IJ YaQ6z  
{ 0Y0z7A:  
nEndPos = nStartPos[i+1]; IYe[IHny1  
} m<n+1  
nEndPos[nEndPos.length-1] = nFileLength; s3Bo'hGxG  
} hzAuj0-A  
} x<t?Yc9  
67/@J)z0%  
pp|$y\ZzB  
//启动子线程 <1vogUDW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; T7qp ({v?Q  
for(int i=0;i<nStartPos.length;i++) &kf \[|y  
{ RQ8"vF#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x6aVNH=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &LV'"2ng8  
nStartPos,nEndPos,i); Z
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HE*^!2f  
fileSplitterFetch.start(); bv7)[,i  
} V~Guw[RA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g1XpERsSEV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); JSFNn]z2P  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *[>{9V  
nEndPos = " + nFileLength); ~&,S xQT  
// fileSplitterFetch[nPos.length-1].start(); m!INbIh  
`_&vvJPn@!  
K z^.v`  
//等待子线程结束 nVpDjUpN  
//int count = 0; wI7.M Gt  
//是否结束while循环 )[99SM   
boolean breakWhile = false; Z2;~{$&M+  
,wr5DQ  
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while(!bStop) B|syb!g  
{ %M_F/O  
write_nPos(); kJ* N`=  
Utility.sleep(500); An]Vx<PD  
breakWhile = true; PYCG#U  
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|
 
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for(int i=0;i<nStartPos.length;i++) D!,'}G#  
{ P/S,dhs(  
if(!fileSplitterFetch.bDownOver) Nt tu)wr  
{ shLMj)7!  
breakWhile = false; )"Ujx`]4r  
break; f!7fz~&Sh  
} ./tZ*sP:  
} JrxQ.,*i  
if(breakWhile) ']!wc8m1"  
break; [$6YPM>Ee  
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//count++; 0{!-h  
//if(count>4) /`qQWB5b  
// siteStop(); ;Gu(Yoa}y  
} }V/iU_)  
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System.err.println("文件下载结束！"); ZXj*Vu$_4  
} -f'&JwE0=  
catch(Exception e){e.printStackTrace ();} 6R2F,b(_  
} MO1H?Uhx  
=BD|uIR  
=q[+e(,3  
//获得文件长度 uC]c`Ue  
public long getFileSize() e
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{ K=4|GZ~p}`  
int nFileLength = -1; B%x?VOdBE  
try{ [pt U}  
URL url = new URL(siteInfoBean.getSSiteURL()); 2L.6!THG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y`z?lmV)xM  
httpConnection.setRequestProperty("User-Agent","NetFox"); B_@p@6z  
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int responseCode=httpConnection.getResponseCode(); cI6Td*vM  
if(responseCode>=400) Bi/E
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{ tHvP0RxM  
processErrorCode(responseCode); Lm^vS u  
return -2; //-2 represent access is error |@B|o-  
} V2yX;u  
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String sHeader;
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for(int i=1;;i++) R-k
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{ vgn,ZcX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x9]vhR/av  
//Utility.log(in.readLine()); A0ZU
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sHeader=httpConnection.getHeaderFieldKey(i); ihct~y-9W  
if(sHeader!=null) ?5[$d{ Gjl  
{ !6 kn>447Y  
if(sHeader.equals("Content-Length")) &`g^b^i  
{ H-% B<7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =Q# (2  
break; %4wHiCOg  
} 2/))Y\~  
} 4?_^7(%p  
else R<r,&X?m  
break; /BS yanro  
} M3fTUCR  
} Q}^qu6  
catch(IOException e){e.printStackTrace ();} I 'ha=PeVn  
catch(Exception e){e.printStackTrace ();} =+VDb5= TV  
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Utility.log(nFileLength); (F#2z\$;  
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return nFileLength; Kciz^)'Z  
} IR8qFWDZ  
2%-/}'G*  
/RF&@NJE5  
//保存下载信息（文件指针位置） 0\1g-kc!v  
private void write_nPos() S""F58H n  
{ bhKe"#m|S  
try{ wEl/s P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); B?d+^sz]  
output.writeInt(nStartPos.length); ;Yt'$D*CP  
for(int i=0;i<nStartPos.length;i++) `@&WELFv{  
{ GC
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// output.writeLong(nPos); F_iZ|B  
output.writeLong(fileSplitterFetch.nStartPos); %YG[?"P'  
output.writeLong(fileSplitterFetch.nEndPos); _]< Tv3]RK  
} 1,n\Osd  
output.close(); ] `;Fc8$  
} OFZo"XtF  
catch(IOException e){e.printStackTrace ();} *b`1+~p_2  
catch(Exception e){e.printStackTrace ();} &<(&u`S  
} 'qoaMJxN`  
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Rf!$n7& \  
//读取保存的下载信息（文件指针位置） mW3IR3b  
private void read_nPos() =)!~t/  
{ !^aJS'aq  
try{ yi<H }&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); q^}iXE~  
int nCount = input.readInt(); G,b*Qn5#  
nStartPos = new long[nCount]; cj|Urt  
nEndPos = new long[nCount]; EiPOY'  
for(int i=0;i<nStartPos.length;i++) C jz(-018  
{ nKch:g  
nStartPos = input.readLong(); 6"2IV  
nEndPos = input.readLong(); 8&y#LeM1TT  
} W#L/|K!S  
input.close(); T9YrB  
} QOv@rP
/  
catch(IOException e){e.printStackTrace ();} 2}9M7Z",2  
catch(Exception e){e.printStackTrace ();} As|e=ut(  
} [n$6T  
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private void processErrorCode(int nErrorCode) ZkF6AF   
{ ?V =#x.9  
System.err.println("Error Code : " + nErrorCode); PSU}
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} Bf$`Hf6  
wd2z=^S~  
B*}:YV  
//停止文件下载 2GRv%:rZ  
public void siteStop() v+DXs!O{  
{ NqN}] nu6  
bStop = true; K#x|/b'5d  
for(int i=0;i<nStartPos.length;i++) WS\Ir-B  
fileSplitterFetch.splitterStop(); S3y(' PeF  
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} l-8rCaq&J  
} pE{Ecrc3|  
//负责部分文件的抓取 B#o6UO\  
**FileSplitterFetch.java $g }aH(vf  
*/ V17!~  
package NetFox; Eu[/* t+l  
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import java.io.*; Bh65qHQO  
import java.net.*; ,HK-mAH   
]}
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public class FileSplitterFetch extends Thread { G54`{V4&s  
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String sURL; //File URL 7DWGYvv[  
long nStartPos; //File Snippet Start Position 8Q73h/3  
long nEndPos; //File Snippet End Position 9[:TWvd  
int nThreadID; //Thread's ID 5p~hUP]tT  
boolean bDownOver = false; //Downing is over SnY{|  
boolean bStop = false; //Stop identical sV]I]DR  
FileAccessI fileAccessI = null; //File Access interface e_IRF+>  
ZQ_AqzT3D  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ULzrJbP'7  
{ o`Q.;1(Y'  
this.sURL = sURL; uP^u:'VjbH  
this.nStartPos = nStart; KESM5p"f  
this.nEndPos = nEnd; bv}e[y
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nThreadID = id; E^m;Ab=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M]SeNYDy  
} eaDG7+iS  
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public void run() BCh|^Pk  
{ ">vi=Tr  
while(nStartPos < nEndPos && !bStop) #GzowI'  
{ 9u%(9Ae  
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try{ !1/F71l DX  
URL url = new URL(sURL); m%s:4Z%=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~re~Ys  
httpConnection.setRequestProperty("User-Agent","NetFox"); f'TEua_`  
String sProperty = "bytes="+nStartPos+"-"; v4F+^0?  
httpConnection.setRequestProperty("RANGE",sProperty); P7$/yBI U  
Utility.log(sProperty); dd*p_4;  
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InputStream input = httpConnection.getInputStream(); W"&,=wvg2  
//logResponseHead(httpConnection); P+DIo7VTX  
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byte[] b = new byte[1024]; DTHWL  
int nRead; P=Su)c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z#2n+hwE  
{ |^"0bu"  
nStartPos += fileAccessI.write(b,0,nRead); S:1g(f*85  
//if(nThreadID == 1) ,(NN)Oj  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h=B= J  
} >~_)2_j  
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Utility.log("Thread " + nThreadID + " is over!"); Q"H/RMo-  
bDownOver = true; L2OR<3*|Av  
//nPos = fileAccessI.write (b,0,nRead); J M`[|"R%  
} Rx?ze(  
catch(Exception e){e.printStackTrace ();} I moxg+u  
} my#\(E+  
} R[@}Lg7+v  
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],Yy)<e.  
//打印回应的头信息 LL==2KNUo  
public void logResponseHead(HttpURLConnection con) /*MioaQB}p  
{ ]'pL*&"X  
for(int i=1;;i++) UqNUX?(  
{ 8{_lB#<[E  
String header=con.getHeaderFieldKey(i); gU1Pb]]  
if(header!=null) L@Q+HN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8[D"  
Utility.log(header+" : "+con.getHeaderField(header)); qw{`?1[+  
else x_r*<?OZ  
break; hw(\3h()  
} lnRL^ }  
} -!}3bl*(7  
n#@Qd!uzM  
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public void splitterStop() F~eY'~&H}  
{ Q!_d6-*u  
bStop = true; (>NZYPw^3  
} 6&il>  
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} Qxk& J  
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/* 5{
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**FileAccess.java y G3aF(  
*//文件访问(定位，写) B{*{9!(l9  
package NetFox; Gr#3GvL  
import java.io.*; (|NCxey  
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public class FileAccessI implements Serializable{ 2_y]MXG+%  
"c|Rpzs[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8QoxU" c&  
RandomAccessFile oSavedFile; w ?*eBLJ(G  
long nPos; A+3SLB  
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public FileAccessI() throws IOException D <R_eK  
{ G? XS-oSv  
this("",0); O1bW, n(  
} t"Ah]sD  
cvG*p||  
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public FileAccessI(String sName,long nPos) throws IOException ex6R=97uA  
{ hzRKv6  
oSavedFile = new RandomAccessFile(sName,"rw"); E&eY79  
this.nPos = nPos; ;j7G$s9  
oSavedFile.seek(nPos); .6xMLo,R  
} m uy^>2p  
Q$v00z]f*  
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public synchronized int write(byte[] b,int nStart,int nLen) ixSr*+  
{ =*"8N-FU  
int n = -1; ]Yw$A  
try{ %qiVbm0  
oSavedFile.write(b,nStart,nLen); +vaA P=  
n = nLen; Ikw@B)0}  
} t%%()!|)j  
catch(IOException e) Q;g7<w17  
{ Cs7ol-\)  
e.printStackTrace (); X-(4/T+v  
} JO+tY[q  
t ^[fu,  
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return n; \2e^
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} 3%5a&b  
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} f:ObI  
/s} "0/Y\  
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/* %^L{K[}  
**SiteInfoBean.java w.a9}GC  
*/ !*Eu(abD  
package NetFox; y<E];ub  
sQac%.H;`U  
 dC{dw^  
public class SiteInfoBean { _io'8X2K%  
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.<F46?HS  
private String sSiteURL; //Site's URL `SsoRPW&$  
private String sFilePath; //Saved File's Path 7XK0vKmW3  
private String sFileName; //Saved File's Name RYjK4xT?Y/  
private int nSplitter; //Count of Splited Downloading File }b&lHr'Uw  
OtmDZ.t;`  
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public SiteInfoBean() Z)M "`2Ur  
{//nSplitter的缺省值为5 _eOC,J<-~  
//default value of nSplitter is 5 ;=jF9mV.  
this("","","",5); V<W;[#"  
} xdg
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[Hx(a.,d  
2&>t,;v@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4,z|hY_*t  
{ VMRfDaO9  
sSiteURL= sURL; !>n!Q*\(Ov  
sFilePath = sPath; b4i=%]v8  
sFileName = sName; XPO-u]<W  
this.nSplitter = nSpiltter; 6]Hwr_/tk  
45sEhs[$  
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} $R/@8qnP W  
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public String getSSiteURL() WSu6chz)  
{ 5@m ,*n&[  
return sSiteURL; ]690ey$E:j  
} (.cA'f?h  
r|u[36NmA  
.Y;
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public void setSSiteURL(String value) _ZK^JS  
{ N*}soMPV^.  
sSiteURL = value; N68$b#9Ry  
} k`8O/J  
!SW0iq[7j  
<@KIDZYC  
public String getSFilePath() <&l$xn  
{ MmN{f~Kq9  
return sFilePath; #0aBQ+_8H  
} e^>>"tr  
['=O>YY  
"Zgwe,#  
public void setSFilePath(String value) #dUKG8-HJ  
{ ,s#~00C|  
sFilePath = value; E5n7 <
 
} Lc{arhN  
'NhQBk  
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public String getSFileName() P\7*ql`  
{ p|t" 4HQ  
return sFileName; `xLsD}32  
} GHcx@||C?  
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at
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public void setSFileName(String value) 'Z4}O_5_  
{ ]u|v7}I4  
sFileName = value; n9+33^ PT  
} E{u6<B*  
z}!g2
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pD%(Y^h?  
public int getNSplitter() O D}RnKL  
{ b?i+nhqI  
return nSplitter; CvY+b^;  
} g%f5hy  
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&L+uu',M0c  
public void setNSplitter(int nCount) \Mg_Q$  
{ 1n8[fgz  
nSplitter = nCount; e.n(NW  
} lLTqk\8g  
} e c&Y2  
kL*P 3 0  
+twoUn{#  
/* ?7aZU  
**Utility.java DO*U7V02  
*/ -+rzc&h  
package NetFox; W\~^*ny P6  
,IjZQ53q~  
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public class Utility { 0hemXvv1  
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public Utility() k."p&  
{ ."$t&[;s  
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} G tI )O}  
:25LQf^nz  
//线程睡眠 7Bp7d/R-  
public static void sleep(int nSecond) H#SQ>vyAV  
{ QhZg{v[d  
try{ CQ!pt@|d  
Thread.sleep(nSecond); 7=CkZ&(?  
} YZg#H)w%  
catch(Exception e) t WI-  
{ AoS7B:T;!  
e.printStackTrace (); ~5N}P>4*  
} 7Z< ~{eD,  
} FDz`U:8  
HT;^
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//日志 ]3_b3@k  
public static void log(String sMsg) +X=*>^G(-  
{ Y,}_LS$f  
System.err.println(sMsg); Jl/wP  
} WoEK #,I;  
nq M7Is  
yq%5h[M  
public static void log(int sMsg) u.GnXuax  
{ 1r;zA<<%R  
System.err.println(sMsg); *&NP?-E  
} w 9dkJo  
} N[e,){v  
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` =>}*GS  
/* M13HD/~O  
**TestMethod.java VzP az\e  
*/ -'&/7e6>y  
package NetFox; [;u#79aE
 
MR#*/Iw~  
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public class TestMethod { 3:+9H}Q  
;]dD\4_hK  
'C[tPP  
public TestMethod() 4ijtx)SA  
{ ///xx/weblogic60b2_win.exe T}#iXgyx  
try{ Hb)FeGsd).  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w' 7sh5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b[74$W{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); T`&zQQ6F'  
fileFetch.start(); /WuYg OI  
} C~ 1]  
catch(Exception e){e.printStackTrace ();} 1R2IlUlzFr  
 &9yZfp  
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} F$7!j$ Z  
_'=,c"  
40t xZFQ0  
public static void main(String[] args) (\AN0_  
{ --5F*a{R|  
new TestMethod(); #EPC]jFk  
} -YA,Stc-  
} 0fsVbC  
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