http断点续传简单实现（java)

/* qD@]FEw!O  
**SiteFileFetch.java <OQn|zU\  
*/ - '<K_e
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package NetFox; U3R;'80 f  
import java.io.*; `x{*P.]N!<  
import java.net.*;
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public class SiteFileFetch extends Thread { Ez\TwK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #(i9G^K  
long[] nStartPos; //开始位置 fD^$ y 8  
long[] nEndPos; //结束位置 7gX#^YkE+k  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _h?hFs,N]  
long nFileLength; //文件长度 41Y1M]`=  
boolean bFirst = true; //是否第一次取文件 ,~z*V;y)  
boolean bStop = false; //停止标志 w"A.*8Iu  
File tmpFile; //文件下载的临时信息 ! MTmG/^  
DataOutputStream output; //输出到文件的输出流 O)bc8DyI  
{`-f<>N3  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） dF@m4U@L  
public SiteFileFetch(SiteInfoBean bean) throws IOException }Kt`du=  
{ -rn%ASye  
siteInfoBean = bean; Nk#[~$Q-1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3FD6.X>x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0Yzm\"Ggv  
if(tmpFile.exists ()) jN[P$}#b`  
{ F gi&CJ8Q  
bFirst = false; v(|Arm?  
read_nPos(); `>i8$q%  
} @N tiT,3k  
else 50<QF  
{ QPc4bg\J~t  
nStartPos = new long[bean.getNSplitter()]; CXI%8eFXe$  
nEndPos = new long[bean.getNSplitter()]; J~}%j.QQ7  
}
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} 0*=[1tdWY  
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public void run() n+'gVEBA  
{ IqA'Vz,lL  
//获得文件长度 b.N$eJlQ&  
//分割文件 [}mx4i  
//实例FileSplitterFetch f/?uosS  
//启动FileSplitterFetch线程 6Z}8"VJr {  
//等待子线程返回 ,8tk]W[C  
try{ ro%Jg  
if(bFirst) l;~b:[r  
{ s*g`| E{M  
nFileLength = getFileSize(); n|p(Cb#G  
if(nFileLength == -1) rf ?\s/#OY  
{ wr) \G
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System.err.println("File Length is not known!"); iImy"$yX{  
} SsY:gp_  
else if(nFileLength == -2) eBZ94rA]  
{ s"'ns  
System.err.println("File is not access!"); Rj'Tu0l  
} (XU(e  
else
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{ '{ $7Dbo  
for(int i=0;i<nStartPos.length;i++) aVE/qXB  
{ 0xEr`]]U  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); iaV%*  
} Sc.@u3  
for(int i=0;i<nEndPos.length-1;i++) 1_=I\zx(  
{ 
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nEndPos = nStartPos[i+1]; #n_gry!5  
} |7$Q'3V  
nEndPos[nEndPos.length-1] = nFileLength; B-1Kfc  
} D;Bij=  
} Qo5yfdR  
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4#Bzq3,|  
//启动子线程 (i1q".  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,6EFJVu \  
for(int i=0;i<nStartPos.length;i++) @'>Ul!.]  
{ )8Jf
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RSTA!?K/.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !q8"Q t  
nStartPos,nEndPos,i); M(|6YF7u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L=_ 
  
fileSplitterFetch.start(); * YR>u@  
} gj@>9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Bo4MoSF}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `'vNHY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,Qh9}I7;C  
nEndPos = " + nFileLength); SR$?pJh D%  
// fileSplitterFetch[nPos.length-1].start(); i"h~QEE  
p[8H!=`K  
:#zVF[Y(2  
//等待子线程结束 O:{N5+HVG  
//int count = 0; i6FviZx  
//是否结束while循环 W%-`  
boolean breakWhile = false; (R|_6[zy  
ml1My1  
mD_sf_2>
 
while(!bStop) ?X'l&k>  
{ NtDxwzj  
write_nPos(); dsG:DS`q  
Utility.sleep(500); aInh?-  
breakWhile = true; \uyZl2=WWa  
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*v:o`{vM[  
for(int i=0;i<nStartPos.length;i++) -d]v6q'1  
{ 0 /)OAw"m  
if(!fileSplitterFetch.bDownOver) 9$WA<1PK+  
{ #PGpB5vnaA  
breakWhile = false; ( d1ho=  
break; NcyE_T  
} i$g6C  
} XE`u  
if(breakWhile) VD90JU]X<  
break; (o2.*x  
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nhLw&V3y  
//count++; _x]q`[Dih  
//if(count>4) @M)"  
// siteStop(); ]A,Og_g  
} y6P-:f/&*  
,K
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System.err.println("文件下载结束！"); tpn.\z%  
} cq4sgQ?sW  
catch(Exception e){e.printStackTrace ();} b~C^cM  
} YfUo=ku  
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vm.%)F#@  
//获得文件长度 BMH?BRi  
public long getFileSize() U1=]iG<%  
{ Ol)
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int nFileLength = -1; fD#!0^  
try{ bqwn_=.  
URL url = new URL(siteInfoBean.getSSiteURL()); zxrbEE Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T( CTU/a-,  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5n1T7-QCL  
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int responseCode=httpConnection.getResponseCode(); k&pV`.Imi  
if(responseCode>=400) #^9a[ZLj0  
{ tKC
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processErrorCode(responseCode); 2!nz>K  
return -2; //-2 represent access is error Id?2(Tg  
} C4|H5H  
/&o<kY  
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String sHeader; t&MLgu  
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for(int i=1;;i++) ,H@ x.  
{ |6w{%xC?"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bI:cYn1  
//Utility.log(in.readLine()); jP )VTk_  
sHeader=httpConnection.getHeaderFieldKey(i); /MbWS(RT  
if(sHeader!=null) 1v'|%B;O  
{ K[[ 5H  
if(sHeader.equals("Content-Length")) wF)g@cw  
{ t/c)[l hV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xP5Z
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break; X-F:)/$xG  
} J8@7 5p9  
} -"x25~k!?F  
else %5Zhq>  
break; MNH-SQB|  
} n=%D}W  
} a9p6[qOcd  
catch(IOException e){e.printStackTrace ();} l*|m(7s  
catch(Exception e){e.printStackTrace ();} POb2U1Sj  
8C
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Utility.log(nFileLength); hEfFMi=a`  
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return nFileLength; RsnFjfb'  
} wQrD(Dv(yA  
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BF(Kaf;<t.  
//保存下载信息（文件指针位置） SAUG+{Uq  
private void write_nPos() dk@iAL*v  
{ Rqun}v}  
try{ #Q

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output = new DataOutputStream(new FileOutputStream(tmpFile)); FfibR\dhY  
output.writeInt(nStartPos.length); I#:,!vjn  
for(int i=0;i<nStartPos.length;i++) &h?8yV4B  
{ 2-DJ3OL]k  
// output.writeLong(nPos); n
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output.writeLong(fileSplitterFetch.nStartPos); 4/QQX;w  
output.writeLong(fileSplitterFetch.nEndPos); Kc{~Q  
} 4 moVS1  
output.close(); Wf9K+my  
} FS6I?q#tQ  
catch(IOException e){e.printStackTrace ();} |&\cr\T\r  
catch(Exception e){e.printStackTrace ();} `l<pH<F  
} =>Dw,+"  
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//读取保存的下载信息（文件指针位置） Ku;8Mx{  
private void read_nPos() 'Q4V(.  
{ rtk1 8U-
 
try{ j(`V&S
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ZN-5W|' O  
int nCount = input.readInt(); Yf[GpSej  
nStartPos = new long[nCount]; IjrjLp[z$  
nEndPos = new long[nCount]; 1" #W1im  
for(int i=0;i<nStartPos.length;i++) Y%YPR=j~ &  
{ |3uE"\nfA  
nStartPos = input.readLong(); e(EXQP2P>  
nEndPos = input.readLong(); Jk=d5B  
} nISfRXU;  
input.close(); )jaNFJ 3  
} O<`\9  
catch(IOException e){e.printStackTrace ();} 82~ZPZG  
catch(Exception e){e.printStackTrace ();} OojQG  
} D(^ |'1  
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private void processErrorCode(int nErrorCode) ^*+-0b;[G  
{ .="[In'  
System.err.println("Error Code : " + nErrorCode); w\Bx=a>vc  
} ^]
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//停止文件下载
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public void siteStop() zoO9N oUHW  
{ ~riV9_-  
bStop = true; F ][QH\N  
for(int i=0;i<nStartPos.length;i++) P1}Fn:Xe%7  
fileSplitterFetch.splitterStop(); Vv5#{+eT;  
*XSHzoT*  
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} ]2'{
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} rd4\N2- 6  
//负责部分文件的抓取 @Z%I
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**FileSplitterFetch.java h?2:'Vu]  
*/ OA\ *)c+F  
package NetFox; 09C[B+>h  
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]Qb85;0)  
import java.io.*; Q]2v]PJ6"  
import java.net.*; _9Y7.5  
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public class FileSplitterFetch extends Thread { @&E{ L  
*Zi:^<hv  
 C#x9RW  
String sURL; //File URL ,T3_*:0hk!  
long nStartPos; //File Snippet Start Position LG3:V'|  
long nEndPos; //File Snippet End Position F3V_rE<  
int nThreadID; //Thread's ID Ah<6m5+
 
boolean bDownOver = false; //Downing is over 7SpF&  
boolean bStop = false; //Stop identical Dt p\T|)  
FileAccessI fileAccessI = null; //File Access interface iPoDesp  
(>gAnebN L  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3~Vo]wv  
{ 8I*
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this.sURL = sURL; cWG?`6xU&  
this.nStartPos = nStart; 2V 9vS  
this.nEndPos = nEnd; qX?k]m   
nThreadID = id; `VxfAV?}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d)X6x-(  
} %knPeo&  
d)7V:  
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public void run() }v?_.MtS  
{ WSPlM"h  
while(nStartPos < nEndPos && !bStop) yhi
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{ _N-JRM m<  
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try{ qf2;yRc&  
URL url = new URL(sURL); 'WW['  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .^J7^Ky,  
httpConnection.setRequestProperty("User-Agent","NetFox"); d5ivtK?  
String sProperty = "bytes="+nStartPos+"-"; yAt,XG3  
httpConnection.setRequestProperty("RANGE",sProperty); \.7O0Q{  
Utility.log(sProperty); E5}wR(i,4  
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InputStream input = httpConnection.getInputStream(); /K./k!'z  
//logResponseHead(httpConnection); (}C%g{8  
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byte[] b = new byte[1024]; #r4S%  
int nRead; M;i4ss,}!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /6%<97/d  
{
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nStartPos += fileAccessI.write(b,0,nRead); P_f>a?OL:  
//if(nThreadID == 1) mVBF2F<4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wEImpsC`  
} u*NU MT2  
@Yy:MdREA  
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Utility.log("Thread " + nThreadID + " is over!"); ages-Z_X  
bDownOver = true; oqOXRUy  
//nPos = fileAccessI.write (b,0,nRead); -gP4| r8&  
} !hJ% :^ xL  
catch(Exception e){e.printStackTrace ();} %hu] =  
} *?#t (Y[  
} ,^_aqH  
 p|D-ez8  
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//打印回应的头信息 /}Z0\,  
public void logResponseHead(HttpURLConnection con) DNy1} 3wg  
{ P|S'MS';:  
for(int i=1;;i++) lilKYrUmG  
{ 96.A8o
 
String header=con.getHeaderFieldKey(i); ]qJ6#sAw75  
if(header!=null) +r+H`cT@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $^2 j#]uX  
Utility.log(header+" : "+con.getHeaderField(header)); kS$HIOt823  
else m_7)r  
break; A~!3svJW  
} ;rj=hc  
} 90pk  

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public void splitterStop() QcQ:hHF  
{ A@wRP8<GKj  
bStop = true; hal3J  
} EuAJ.n  
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} o6$Q>g`]  
3
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/* 7]q$sQ  
**FileAccess.java hwmpiyu  
*//文件访问(定位，写) 4g#pQ  
package NetFox; Q-[^!RAK?  
import java.io.*; ~lR"3z_Z}  
&pZUe`3  

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public class FileAccessI implements Serializable{ %NbhR(  
0;-S){  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {.We%{
4V  
RandomAccessFile oSavedFile; 1R/=as,R  
long nPos; 7/;Xt&  
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public FileAccessI() throws IOException wR;_x x  
{ ]FLuiC  
this("",0); <d
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} uBk$zs  
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x C'>W"pY  
public FileAccessI(String sName,long nPos) throws IOException DVYY1!j<  
{ ]?L?q2>&  
oSavedFile = new RandomAccessFile(sName,"rw"); <3;/,>^ Pm  
this.nPos = nPos; HFwT  
oSavedFile.seek(nPos); V%pdXM5  
} )gNHD?4x  
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public synchronized int write(byte[] b,int nStart,int nLen) ,\5]n&T;r  
{ Vkex&?>v$  
int n = -1; bw{%X  
try{ >RxZ-.,a  
oSavedFile.write(b,nStart,nLen); T7YzO,b/   
n = nLen; VGBL<X  
} SZ-%0z  
catch(IOException e) l[^bo/  
{ R|{6JsjG10  
e.printStackTrace (); ]"^GRFK5  
} (jCE&'?}  
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return n; o([+Pp  
} s&vOwPmV  
U %Aj~K^b  
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} T7n;Bf  
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;W#G<M&n'  
/* +bd/*^  
**SiteInfoBean.java l\5qa_{z  
*/ Arz> P@EQ  
package NetFox; J?5O2n  
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public class SiteInfoBean { NF0} eom  
F1?@tcr'  
<4*7HY[  
private String sSiteURL; //Site's URL $$\| 3rj!  
private String sFilePath; //Saved File's Path 0;e>kz3o  
private String sFileName; //Saved File's Name Cs%'Af  
private int nSplitter; //Count of Splited Downloading File Y&k'4Y%  
2`t4@T  
x&)
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public SiteInfoBean() 4MRHz{`wa  
{//nSplitter的缺省值为5 CN: 36  
//default value of nSplitter is 5 <s-_ieW'  
this("","","",5); ? Z8_(e0U  
} av wU)6L  
1kl4X3q6  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vK#xA+W  
{ b
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sSiteURL= sURL; w0moC9#$?  
sFilePath = sPath; ep[7#\}5  
sFileName = sName; y{K~g<VL  
this.nSplitter = nSpiltter; ?{cF'RB.  
!e.@Xk.P6  
j/wNPB/NM  
} nb22bXt  
n7X3aoVV  
?mRU9VY  
public String getSSiteURL() IcPIOCmOc  
{ Pp3t
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return sSiteURL; :!3CoC.X|c  
} u&bo32fc  
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u-j$
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public void setSSiteURL(String value) tb&{[|O^  
{ Fg5c;sls  
sSiteURL = value; ^b;.zhp8;N  
} V'^s5  
.knRH^  
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public String getSFilePath() d'^jekh  
{ |;{wy  
return sFilePath; .'+Tnu(5q  
} &OGY?[n  
v.\1-Q?  
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public void setSFilePath(String value) =wU08}  
{ InNuK
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sFilePath = value; '!{zO" 1*  
}  $C(}  
E n{vCN  
eNu`\  
public String getSFileName() tQz-tQg  
{ N\HOo-X  
return sFileName; WK/Byd.Z  
} 98Pt&C?-B  
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<G\q/!@_  
public void setSFileName(String value) O)`R)MQ)  
{ 2
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sFileName = value; gHvxmIG  
} l5D8DvJCj  
#Cvjv; QwY  
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public int getNSplitter() JL`n12$m  
{ *8,]fBUq  
return nSplitter; MBXumc_g  
} sh:sPzQ%Jv  
ga6M8eOI  
~e ]83?  
public void setNSplitter(int nCount) l>7`D3  
{ e<9IwS!/  
nSplitter = nCount; <.s[x~b\`  
} vDv:3qN7(  
} a0CmCv2#  
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DP &,jU6  
/* FuLP{]Y+AM  
**Utility.java  9'\18_w  
*/ :)cPc7$8  
package NetFox; D$I7Gz,w{  
Q
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public class Utility { .1[K\t)
2  
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public Utility() DZilK:  
{ "S_t%m&R  
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} qOV#$dkY  
,N?~je.  
//线程睡眠 }O<=!^Y;A  
public static void sleep(int nSecond) sD_Z`1  
{ }R;.~F  
try{ %'%ej^s-R  
Thread.sleep(nSecond); ]j~V01p/e  
} 1ePZs$   
catch(Exception e) 4!XB?-.  
{ M`9qo8zCi  
e.printStackTrace (); `QnKal)  
} '_@Y  
} Ky8sLm@  
imZi7o  
//日志 fJH09:@^%  
public static void log(String sMsg) py]m^)yc  
{ 0 j:8Ve  
System.err.println(sMsg); J;Xh{3[vO  
} g>1yQ  
z+@aQ@75  
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public static void log(int sMsg) m$NBGw  
{ P|!GXkS  
System.err.println(sMsg); `kpX}cKK}  
} `M6!V  
} E*:!G  
1j`-lD  
M$B
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/* lQ<2Vw#Yl  
**TestMethod.java +\fr3@Yc  
*/ =!*e; L  
package NetFox; j#f+0  
C\ZL*,%}  
xdd7OSc0{  
public class TestMethod { 0~iC#lHO  

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9TIyY`2!  
public TestMethod() O#7ONQfBO  
{ ///xx/weblogic60b2_win.exe Hz
cy'  
try{ :2pd2S  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9%S{fd\#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <Bn^+u\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); : ^F+mQN  
fileFetch.start(); GpMKOjVm|  
} `MAee8u'  
catch(Exception e){e.printStackTrace ();} X/gIH/  
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} KkP}z  
1P. W 34  
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public static void main(String[] args) :9Z
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{ nm'sub  
new TestMethod(); {>H#/I8si  
} 6vbWe@#U/  
} nfJ|&'T  
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