http断点续传简单实现（java)

/* !p4FK]B/u  
**SiteFileFetch.java kn6X I*
 
*/ <t. w(?  
package NetFox; &4Y@-;REt  
import java.io.*; [b@9V
_  
import java.net.*; h/#s\>)T  
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public class SiteFileFetch extends Thread { b_oUG_B3]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean XO4rrAYvW  
long[] nStartPos; //开始位置 u[coWaPsZ  
long[] nEndPos; //结束位置 ldWr-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .^uYr^(|[  
long nFileLength; //文件长度 xA"7a  
boolean bFirst = true; //是否第一次取文件 V?Ye^-29  
boolean bStop = false; //停止标志 C)0JcM  
File tmpFile; //文件下载的临时信息 ITEd[ @^d  
DataOutputStream output; //输出到文件的输出流 FtxmCIVIV~  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {@`Z`h"N  
public SiteFileFetch(SiteInfoBean bean) throws IOException E3o J
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{ <*74t%AJ%  
siteInfoBean = bean; 4w0Y(y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /g]m,Y{OI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _#6ekl|%  
if(tmpFile.exists ()) ,;-55|o\V  
{ }\)O1  
bFirst = false; Wq]Lb:&{a  
read_nPos(); ih/MW_t=m=  
} F;_L/8Ov1  
else )]C7+{ImC  
{ 66l$}+|Zzc  
nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()]; ,Q8)r0c  
} WD,iY_'7u^  
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} C@L8,Kj ~.  
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public void run() |0$wRl+kN  
{ o Z#4<7K  
//获得文件长度 i0-zGEMB.  
//分割文件 [#emm
1k  
//实例FileSplitterFetch amK.H"  
//启动FileSplitterFetch线程 O0i[GCtP5  
//等待子线程返回 @4N@cM0   
try{ vg5;F[e  
if(bFirst) sOBy)vq?\  
{ "##Ylq("  
nFileLength = getFileSize(); E#=slj@  
if(nFileLength == -1) Zn`vL52_  
{ 8UyYN$7V  
System.err.println("File Length is not known!"); hw [G  
} |?Z;tAF!  
else if(nFileLength == -2) R8lBhLs  
{ <ZV !fn  
System.err.println("File is not access!"); b4$-?f?V  
} /M;A)z  
else A9[ELD>p  
{ v~N8H+!d  
for(int i=0;i<nStartPos.length;i++)
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{  d
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nStartPos = (long)(i*(nFileLength/nStartPos.length));  m%-  
} )kSE5|:pi  
for(int i=0;i<nEndPos.length-1;i++) I-Ya#s#m  
{ 4$oX
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nEndPos = nStartPos[i+1]; XO*62>Ed  
} BiQ7r=Dd.  
nEndPos[nEndPos.length-1] = nFileLength; b NB
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} _[8BAm  
} '1[}PmhD  
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VQ/<MY C  
//启动子线程 UGNFWZ c  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |5 sI=?p&t  
for(int i=0;i<nStartPos.length;i++) piE9qXn  
{ YY(,H!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c[4H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /XG4O  
nStartPos,nEndPos,i); C<GS._V&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OQ>r;)/  
fileSplitterFetch.start(); w1-/U+0o  
} x;,H>!r"i  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oGi;S=
"I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); H1H+TTZr  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1k2+eI  
nEndPos = " + nFileLength); URbu=U  
// fileSplitterFetch[nPos.length-1].start(); 0^VA,QkQ\  
Nb2]}; O  
8}FZ1h2 4  
//等待子线程结束 o7N3:)  
//int count = 0; Tti]H9g_  
//是否结束while循环 =6Dz<Lq  
boolean breakWhile = false;  hfpSxL  
#WD}XOA  
|kL^k{=zV  
while(!bStop) v:c_q]z#B  
{ ln#Jb&u  
write_nPos(); z\Vu`Yz  
Utility.sleep(500); eJ+V!K'H2  
breakWhile = true; lPL>8.j  
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for(int i=0;i<nStartPos.length;i++) F0O"rN{  
{ (B@:0}>  
if(!fileSplitterFetch.bDownOver) yDBS : \  
{ xWX1P%`  
breakWhile = false;  GU99!.$  
break; \'I->O]  
} sfSM7f  
} gbOd(ugH  
if(breakWhile) ;EZ$8|  
break; +Z0@z^6\  
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H
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//count++; ;h>s=D,r  
//if(count>4) 'ojI_%9<  
// siteStop(); >'3J. FY  
} J,ZvaF  
Xk[;MZ[  
y#HDJ=2  
System.err.println("文件下载结束！"); OHixOI$O  
} iJ HOLz"!  
catch(Exception e){e.printStackTrace ();} g3@Qn?(j!  
} bV_@
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"' g*_  
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//获得文件长度 .Cfi/  
public long getFileSize() zj.;O#hW  
{ .Ua|KKK C  
int nFileLength = -1; *C*n(the  
try{ zCxr]md  
URL url = new URL(siteInfoBean.getSSiteURL()); `!<RP'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?5d7J,"<h  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6XPf0Gl  
/7Z;/|oU  
AW;"` ].  
int responseCode=httpConnection.getResponseCode(); q~9Y&>D  
if(responseCode>=400) B.nq3;Y  
{ x}I'
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processErrorCode(responseCode); g+Z~"O]$M  
return -2; //-2 represent access is error Jsf-t  
} .0^-a=/  
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String sHeader; 8Qtd,  
^W
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for(int i=1;;i++) |7XV!D!\g  
{ j. 1@{H  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }A@op+0E  
//Utility.log(in.readLine()); :G+8%pUX]  
sHeader=httpConnection.getHeaderFieldKey(i); Gn}G$uk61  
if(sHeader!=null) GabYxYK  
{ :by EXe;3  
if(sHeader.equals("Content-Length")) 1=fP68n  
{ _M.7%k/U8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #SNwSx&
 
break; ]w2nVC3  
} 19.+"H  
} U Ke!zI  
else v[S>   
break; FdT@}  
} P.G`ED|K!Y  
} {(o$? =  
catch(IOException e){e.printStackTrace ();} 9 gt$z}oU  
catch(Exception e){e.printStackTrace ();} s*A#;  
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{*EA5;  
Utility.log(nFileLength); nP9zTa  
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return nFileLength; nJEm&"AI  
} &
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:nk$?5ib  
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//保存下载信息（文件指针位置） K x7'm1  
private void write_nPos() nYfZ[Q>v  
{ }E?{M~"<  
try{ (`z
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output = new DataOutputStream(new FileOutputStream(tmpFile)); Iu<RwB[#Q  
output.writeInt(nStartPos.length); lRIS&9vA3  
for(int i=0;i<nStartPos.length;i++) X?p.U  
{ ?`jh5Kw%y  
// output.writeLong(nPos); N~<H`  
output.writeLong(fileSplitterFetch.nStartPos); Wnp\yx`  
output.writeLong(fileSplitterFetch.nEndPos); &y164xn'h  
} zkFx2(Hq-f  
output.close();  3+[R
!  
} uif1)y`Q$C  
catch(IOException e){e.printStackTrace ();} })zYo 7  
catch(Exception e){e.printStackTrace ();}
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} *b< a@  
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>^<%9{  
//读取保存的下载信息（文件指针位置） =Zg%& J  
private void read_nPos() s<}d)
L(  
{ 82mKI+9&"  
try{ q4'Vb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); YIb=rR[ $  
int nCount = input.readInt(); m^6& !`CD  
nStartPos = new long[nCount]; epWTZV(1x  
nEndPos = new long[nCount]; Stw%OP@?  
for(int i=0;i<nStartPos.length;i++) 7RH1,k  
{ SHc<`M'+  
nStartPos = input.readLong(); >= G{
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nEndPos = input.readLong(); y;M}I8W[  
} 
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input.close(); WAzYnl'p  
} HAkEJgV  
catch(IOException e){e.printStackTrace ();} FCk4[qOp7  
catch(Exception e){e.printStackTrace ();} sYt\3/yL'  
} zvzS$Gpe  
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private void processErrorCode(int nErrorCode) #Tr>[ZC  
{  k|Xxr  
System.err.println("Error Code : " + nErrorCode); X=sC8Edx  
} UJ}Xa&*H\  
;q8tOvQ  
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//停止文件下载 C4Tn  
public void siteStop() %[l*:05  
{ iyj,0
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bStop = true; hkK+BmMj\  
for(int i=0;i<nStartPos.length;i++) H[cHF  
fileSplitterFetch.splitterStop(); j@j%)CCM  
U c6]]Bbc  
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} tHvc*D  
} QNGICG-  
//负责部分文件的抓取 u{H'evv0O  
**FileSplitterFetch.java R(i2TAaaU  
*/ qtqTLl@u  
package NetFox; Vy+%sG q"  

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FN25,Q8:*I  
import java.io.*; GaD]qeS-K  
import java.net.*; y .+d3  
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public class FileSplitterFetch extends Thread { nE~HcxE/  
N@oNg}D&:  
v(ATbY75  
String sURL; //File URL +[=yLE#P%  
long nStartPos; //File Snippet Start Position QGWfF,q  
long nEndPos; //File Snippet End Position \Y EV 5  
int nThreadID; //Thread's ID isdEs k#A.  
boolean bDownOver = false; //Downing is over %LL*V|  
boolean bStop = false; //Stop identical :3
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FileAccessI fileAccessI = null; //File Access interface x vi&d1  
uv:DO6 {  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException BUuU#e5  
{ :4{;^|RgU  
this.sURL = sURL; "8bxb  
this.nStartPos = nStart; :sMc}k?9S  
this.nEndPos = nEnd; v4:g*MD?~  
nThreadID = id; 1pUIZ$@?`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Is87 9_Z  
} efK)6T^p  
*kI1NchF  
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public void run() 2MNAY%iT  
{  J
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while(nStartPos < nEndPos && !bStop) xaiA?  
{ tRqg')y  
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try{ \X'{ ee  
URL url = new URL(sURL); _` %z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {kLL&`ii  
httpConnection.setRequestProperty("User-Agent","NetFox"); l )hg!(  
String sProperty = "bytes="+nStartPos+"-"; G4jaHpPi  
httpConnection.setRequestProperty("RANGE",sProperty); ;'o:1{Y  
Utility.log(sProperty); N"i'[!H%  
7qyv.{+  
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InputStream input = httpConnection.getInputStream(); IZ2c<B5&  
//logResponseHead(httpConnection); nUZ+N)*  
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byte[] b = new byte[1024]; zuWfR&U|W  
int nRead; 67uUeCW  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p'2ZDd=v  
{ va(ZGGS]N  
nStartPos += fileAccessI.write(b,0,nRead); ODGOWw0  
//if(nThreadID == 1) G3
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UuV<#N)  
} :v_H;UU  
5"f')MKUV9  
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Utility.log("Thread " + nThreadID + " is over!"); );LkEXC_'  
bDownOver = true; w$JG:y#  
//nPos = fileAccessI.write (b,0,nRead); @wWro?s'p  
} _084GK9{W  
catch(Exception e){e.printStackTrace ();} it2@hZc5  
} `-l,`7e'  
} JRMe(,u  
=[O;/~J%:  
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//打印回应的头信息 09Sy- je*/  
public void logResponseHead(HttpURLConnection con) ! H)D@,@&  
{ ,0^:q)_  
for(int i=1;;i++) x(e=@/qp  
{ %ZF6%m0S  
String header=con.getHeaderFieldKey(i); _)q,:g~fu  
if(header!=null) EJ*  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); J$)lYSNE  
else G)A5;u\P9  
break; O87Ptr8  
} m6P!#=a:l<  
} r)jj]$0  
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y//yLrs;  
public void splitterStop() 7`^]:t  
{ 8$fiq}a  
bStop = true; YuWsE4$  
} Z3K~C_0Cnu  
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ni#!Gxw  
} hP4*S^l  
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/* zWxKp;.  
**FileAccess.java Ju$vuE
O  
*//文件访问(定位，写) LPgP;%ohO/  
package NetFox; B]K@'#  
import java.io.*; :^mfTj$  
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public class FileAccessI implements Serializable{ Z6<vLc  
SSANt?\Z<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 W`fE@*k0  
RandomAccessFile oSavedFile; *N"bn'>3  
long nPos; |C9qM  
xN\PQ,J  
*pN,@ZV$  
public FileAccessI() throws IOException h<oQ9zW
)  
{ U!sv6=(y@  
this("",0); ".z~c%'  
} @b=b>V[d6  
p1 tfN$-  
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public FileAccessI(String sName,long nPos) throws IOException 8
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{ 8phcekh+  
oSavedFile = new RandomAccessFile(sName,"rw"); 24 S,w>j  
this.nPos = nPos; ;ti{ #(Ux  
oSavedFile.seek(nPos); kW&{0xkGR  
} #2c-@),  
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public synchronized int write(byte[] b,int nStart,int nLen) 
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{ 8o~<\eF%  
int n = -1; -b-P
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try{ 5gWn{[[e)y  
oSavedFile.write(b,nStart,nLen); $l}MB7
 
n = nLen; 7SE=otZ>  
} ?6@Y"5 z3g  
catch(IOException e) 5Bw  
{ W`]
,  
e.printStackTrace (); j'i-XIs  
} DJlY~}v#_  
:
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@Nb&f<+gi  
return n; 9PEjV$0E2  
} ):C4"2l3  
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} -nG3(n&wB  
'3eP<earRP  
}9e4?7  
/* r7sPFM  
**SiteInfoBean.java Bv
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*/ pdsjX)O+f  
package NetFox; NMY~f (x  

+\9Y;Ny  
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public class SiteInfoBean { f+Nq?GvwBQ  
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private String sSiteURL; //Site's URL 3/o-\wWO  
private String sFilePath; //Saved File's Path z (rQ6  
private String sFileName; //Saved File's Name nGGYKI  
private int nSplitter; //Count of Splited Downloading File ~^=QBwDW8N  
M~;Ww-./  
NvXds;EC  
public SiteInfoBean() swuW6p  
{//nSplitter的缺省值为5 a9}cpfG=)  
//default value of nSplitter is 5 25h.u>6@{  
this("","","",5); o <8L,u(U  
} ~P|YAaFx  
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HgE^#qD?  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3t[2Bd  
{ d@pD5n=m;  
sSiteURL= sURL; @v_ )(  
sFilePath = sPath; v"
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sFileName = sName; sCSrwsbhv  
this.nSplitter = nSpiltter; fZH:&EP  
f$9V_j-K+  
8$-(%  
} Rer\='  
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Z ) qc-~S  
public String getSSiteURL() j*<H18^G  
{ Hn0,LH$/  
return sSiteURL; i1ur>4Ns  
} 2Q,e1'=  
a_w#,^/P  
2#ND(  
public void setSSiteURL(String value) ([iMOE[D3  
{ I0sd%'Ht?  
sSiteURL = value; "zJ1vIZY  
} )FGm5-K@  
_a"5[sG  
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public String getSFilePath() DzYi> E:*  
{ 4a00-y='  
return sFilePath; 4!,x3H'  
} |7 ]v&?y  
h
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public void setSFilePath(String value) {<o_6 z`$  
{ sL75C|f9  
sFilePath = value; oOUL<ihe?  
} 5ycccMx0V  
lX/s Q  
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public String getSFileName() f1y3l1/  
{ yt}Ve6 m  
return sFileName; x hBlv  
} I9rWut@+  
/]=Ih  
Lqq RuKi  
public void setSFileName(String value) 4*< x0  
{ {Y6U%HG{{r  
sFileName = value; NK;%c-r0v7  
} b^_#f:_j
 
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eG*<
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public int getNSplitter() tSran  
{ fT.18{'>  
return nSplitter; $OB2ZS"  
} S#_g/3w  
_[u&
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public void setNSplitter(int nCount) ?XN=Er^
 
{ kN_ i0~y@-  
nSplitter = nCount; :_V9Jw
u  
} o.W:R Ux  
} WyciIO1  
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/* + 2v6fan  
**Utility.java CAg~K[  
*/ BBuI|lr  
package NetFox; Tq{+9+
 
~SUrbRaY>  
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public class Utility { 3kfrOf.4h  
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7  
public Utility() 0%J0.USkM7  
{ 4A0 ,N8ja}  
=2v/f_  
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} XzLB#0  
h|~I'M]*  
//线程睡眠 mD@*vq  
public static void sleep(int nSecond) tSibzl~  
{
{<ms;Oi'  
try{ wr);+.T9R  
Thread.sleep(nSecond); $O nh2 ^  
} EZs"?A  
catch(Exception e) K(jo[S  
{
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6  
e.printStackTrace (); ~]f6@n  
} rnAQwm-8O%  
} @vyq?H$U;N  
7pPaHX8  
//日志 suKr//_  
public static void log(String sMsg) B|WM;Y^  
{ ya3k;j2C  
System.err.println(sMsg); pW&K=,7|  
} tzIcR #Z  
B^;"<2b*  
*Wj]e%  
public static void log(int sMsg) ?iXN..6x  
{ Ww=^P{q\  
System.err.println(sMsg); *jQ?(Tf  
} #jj+/>ZOi  
} jouA ]E  
jK^Q5iD  
9{*$[%d1  
/* "ov270:  
**TestMethod.java B,S~Idr}  
*/ <
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package NetFox; '3|fv{I  
;F_pF+&q  
/7N&4FrG  
public class TestMethod { 7Is:hx|:  
.G
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9Bao~(j/k  
public TestMethod() *fCmZ$U:{  
{ ///xx/weblogic60b2_win.exe c/DK31K  
try{ x^zw1e,y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  Q}9!aB,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pC~M5(F_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j:2TicHDC  
fileFetch.start(); vf5q8/a  
} a[_IG-l|i4  
catch(Exception e){e.printStackTrace ();} Kn=0AdM  
^c<8|lK L@  
+70x0z2  
} !,|-{":  
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public static void main(String[] args) Jmuyd\?,b  
{ n$r
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new TestMethod(); QWc,J
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} u69UUkG  
} U8.V Rn  
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