http断点续传简单实现（java)

/* [9m3@Yd'  
**SiteFileFetch.java g`XngRb|j  
*/ ;tOsA
#  
package NetFox; ^_2c\mw_I  
import java.io.*; CMt<oT6.?  
import java.net.*; $O"ss>8Se  
/
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public class SiteFileFetch extends Thread { }w0pi  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X
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long[] nStartPos; //开始位置 UP
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long[] nEndPos; //结束位置 w#A)B<Y/"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [!'+}  
long nFileLength; //文件长度 6Yu:v  
boolean bFirst = true; //是否第一次取文件 YpZB-9Krf  
boolean bStop = false; //停止标志 1"h"(dA  
File tmpFile; //文件下载的临时信息 Jw)JV~/0  
DataOutputStream output; //输出到文件的输出流 =pH2V^<<#  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BU`X_Z1)  
public SiteFileFetch(SiteInfoBean bean) throws IOException E~!$&9\  
{ 7'0Vb!(  
siteInfoBean = bean; M0V<Ay\%O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y|Iq~
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]aX@(3G1s  
if(tmpFile.exists ()) $:9t(X)H  
{ c*bvZC^6  
bFirst = false; _imuyt".+  
read_nPos(); {bj!]j
 
} #<{v~sVp&  
else EVmBLH-a  
{ 6
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nStartPos = new long[bean.getNSplitter()];  X\^nV  
nEndPos = new long[bean.getNSplitter()]; 1IXtu  
} )Z7Vm2a  
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} H
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public void run() sSM"~_y\  
{ l;-Ml{}|0  
//获得文件长度 t7=D$ua  
//分割文件 2Tp2{"sB>A  
//实例FileSplitterFetch S?~0)EXj(  
//启动FileSplitterFetch线程 gx&es\  
//等待子线程返回 y|`-)fY  
try{ 1J?v\S$ma`  
if(bFirst) 5EYG
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{ .9
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nFileLength = getFileSize(); fz'qB-F Y  
if(nFileLength == -1) vDjH $ U  
{ 2 bc&sU)X  
System.err.println("File Length is not known!"); & 3#7>
oQ  
} I8xdE(o8+  
else if(nFileLength == -2) m2]N%Y  
{ o[Iu9.zJpy  
System.err.println("File is not access!"); f{BF%;  
} n0(Q/  
else f%G\'q]#F  
{ U]PB)  
for(int i=0;i<nStartPos.length;i++) !~#zd]0x;  
{ pH'_k k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l\<.*6r  
} fO<40!%9cQ  
for(int i=0;i<nEndPos.length-1;i++) gOF^?M11x  
{ p9v:T1?  
nEndPos = nStartPos[i+1]; +nYFLe  
} d$
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nEndPos[nEndPos.length-1] = nFileLength; 0 R6:3fV6R  
} ?sN{U\  
} U1\7Hcs$  
4 m:h&^`N  
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//启动子线程 R)NSJ-A!2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !%>RHh[  
for(int i=0;i<nStartPos.length;i++) h"FI]jK|}  
{ $1f2'_`8~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lQ8hY$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g'.OzD  
nStartPos,nEndPos,i); ;1k&}v&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E&U_1D9=L<  
fileSplitterFetch.start(); >kXscbRL7  
} :i.@d?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "O34 E?ql.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \|=6<ZY:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", oe<i\uX8z  
nEndPos = " + nFileLength); u\\t~<8  
// fileSplitterFetch[nPos.length-1].start(); HP# SR';E  
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//等待子线程结束 AtQ.H-8r  
//int count = 0; $*q|}Tvl#  
//是否结束while循环 9q'9i9/3d  
boolean breakWhile = false; "U\RN  
UtQj<18<  
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while(!bStop) qTJhYxm  
{ (&}[2pb!  
write_nPos(); C4+DZ<pE  
Utility.sleep(500); gN/<g8  
breakWhile = true; C;W@OS-;  
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for(int i=0;i<nStartPos.length;i++) }c/p;<  
{ wGy
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if(!fileSplitterFetch.bDownOver) __=53]jGE  
{ 3FBLCD3  
breakWhile = false; !se1W5ke#  
break; &'uP?r9c$  
} ;cMQ0e  
} '1mk;%  
if(breakWhile) )eZK/>L&  
break; u/=hueR<^  
g p:0Y  
o=rR^Z$G   
//count++;
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//if(count>4) ~$J;yo
~  
// siteStop(); yqN`R\d  
} c p"K?)  
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System.err.println("文件下载结束！"); pGs?Y81  
} [)"\Aq  
catch(Exception e){e.printStackTrace ();} }0'LKwIR  
} |]7c&`  
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//获得文件长度 Xg dBLb  
public long getFileSize() /4x\}qvU  
{ Q yqOtRk  
int nFileLength = -1; Kd:l8%+  
try{ %o?)`z9-  
URL url = new URL(siteInfoBean.getSSiteURL()); DQ.
4b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A5nggg4  
httpConnection.setRequestProperty("User-Agent","NetFox"); u W]gBhO$O  
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int responseCode=httpConnection.getResponseCode(); QAkK5,`vV.  
if(responseCode>=400) |=0vgwd"S  
{ 78l);/E{v  
processErrorCode(responseCode); yCQvo(V[F  
return -2; //-2 represent access is error OAXA<  
} IxbQ6  
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String sHeader; WARiw[  
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for(int i=1;;i++) i-|N6J  
{ 7yE\,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [* <x)  
//Utility.log(in.readLine()); S~/2Bw!2  
sHeader=httpConnection.getHeaderFieldKey(i); :E9pdx+  
if(sHeader!=null) /EjXyrn2  
{ coXg]bUKo  
if(sHeader.equals("Content-Length")) ?t'V5$k\  
{ Im6gWDdq@6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v0C+DKi  
break; |]G%b[
 
} 
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} }u8(7  
else Ta\F~$M  
break; u8c@q'_  
} Sr \y1nt  
} ;"M6}5dQ4  
catch(IOException e){e.printStackTrace ();} ~vXbh(MX  
catch(Exception e){e.printStackTrace ();} 8dR `T}  
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Utility.log(nFileLength); |enLv12Gm  
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return nFileLength; 6Z|h>H5a  
} 3dN`Q:1R9  
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//保存下载信息（文件指针位置） fXMY.X>f  
private void write_nPos() |OeWM  
{ [q|W*[B:@  
try{ C>|.0:[%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); h(=<-p@  
output.writeInt(nStartPos.length); A:m+v{*`4  
for(int i=0;i<nStartPos.length;i++)  qNJc*@s  
{ SCfp5W7~  
// output.writeLong(nPos); !h#ZbErW  
output.writeLong(fileSplitterFetch.nStartPos); %SC Jmn2  
output.writeLong(fileSplitterFetch.nEndPos); kt6)F&;$  
} rR6}  
output.close(); #LR4%}mg  
} !q+ #JW  
catch(IOException e){e.printStackTrace ();} D('.17  
catch(Exception e){e.printStackTrace ();} 7"!`<5o^  
} 7<su8*?  
#G#gc`S-,  
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//读取保存的下载信息（文件指针位置） # Wi?I=,  
private void read_nPos() ~61b^L}$  
{ d.?}>jl  
try{ #@oB2%&X?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); VpJKH\)Rt(  
int nCount = input.readInt(); b
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nStartPos = new long[nCount]; 3YMqp~4  
nEndPos = new long[nCount]; Ba[,9l[  
for(int i=0;i<nStartPos.length;i++) Qs\a&Q=0H  
{ U)G.Bst  
nStartPos = input.readLong(); e*Wk;D&  
nEndPos = input.readLong(); x*H#?.E  
} V;eaQ  
input.close(); Il [~  
} !JXiTI!  
catch(IOException e){e.printStackTrace ();} 1 !_p  
catch(Exception e){e.printStackTrace ();} 1r=cCM  
} ;qaPK2a8  
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private void processErrorCode(int nErrorCode) ,]EhDW6  
{ Mz&/.A  
System.err.println("Error Code : " + nErrorCode); l:'#pZ4T  
} 0!,uo\`  
/<)Vd  
KRL.TLgq)  
//停止文件下载 X&WP.n)  
public void siteStop() Z5Lmg  
{ fHd[8{;P:  
bStop = true; %rrA]\C'  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); l Xa/5QKC  
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} t.8r~2(?  
} V22z-$cb  
//负责部分文件的抓取 QdgJNT<=H,  
**FileSplitterFetch.java ;mEn@@{  
*/ 4|K\pCw  
package NetFox; <yipy[D  
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import java.io.*; d@ K-Z
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import java.net.*; 4-.W~C'Q  
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public class FileSplitterFetch extends Thread { ]qqgEZ1!Y  
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String sURL; //File URL {A/^;
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long nStartPos; //File Snippet Start Position 8;?4rrS  
long nEndPos; //File Snippet End Position =sk[I0W  
int nThreadID; //Thread's ID ~1+6gG  
boolean bDownOver = false; //Downing is over :\|A.# U  
boolean bStop = false; //Stop identical GqHW.s5  
FileAccessI fileAccessI = null; //File Access interface =dPokLXn  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |^l_F1+w  
{ -
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this.sURL = sURL;  p?f\/  
this.nStartPos = nStart; bVzi^R"  
this.nEndPos = nEnd; }O*`I(  
nThreadID = id; dJgLS^1E  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;~<To9O  
} KFbB}oId  
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public void run() 5;}W=x^$a  
{ Uuy$F  
while(nStartPos < nEndPos && !bStop) 0S4BV%7F  
{ ?Ujg.xo\  
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try{ /-p!|T}w  
URL url = new URL(sURL); K#+?oFo:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 14 & KE3`  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^i%S}VK  
String sProperty = "bytes="+nStartPos+"-"; (|BY<Ac3  
httpConnection.setRequestProperty("RANGE",sProperty); Ip'tB4Mq  
Utility.log(sProperty); ]i#p2?BR  
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InputStream input = httpConnection.getInputStream(); KZjh<sjX|  
//logResponseHead(httpConnection); ~bZ=]i  

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byte[] b = new byte[1024]; g$s;;V/8e
 
int nRead; ZHK>0>;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O#U maNj/  
{ ."+lij=56  
nStartPos += fileAccessI.write(b,0,nRead); 8)0]cX  
//if(nThreadID == 1) 0:v!'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n.+'9Fj  
} LH4A!a]  
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Utility.log("Thread " + nThreadID + " is over!"); S[K5ofV  
bDownOver = true; p{L;)WTI  
//nPos = fileAccessI.write (b,0,nRead); 1*8;)#%&  
} cp@Fj"  
catch(Exception e){e.printStackTrace ();} 2X
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} j+h+Y|4J  
} `xzKRId0  
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//打印回应的头信息 #zl1#TC{(  
public void logResponseHead(HttpURLConnection con) 0 SSdp<  
{ b11I$b #  
for(int i=1;;i++) K[y")ooE<j  
{ R@K\  
String header=con.getHeaderFieldKey(i); D<J'\
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if(header!=null) 8lV:-"+
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); t.ulG *  
Utility.log(header+" : "+con.getHeaderField(header)); M>i(p%  
else NTt4sWP!I  
break; ipn-HUrE@  
} DDr\Kv)k(  
} VwI  
#p(c{L!  
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public void splitterStop() 2V@5:tf  
{ *5PQ>d G  
bStop = true; =v<w29P(g  
} YcA. Bn|as  
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} */e$S[5  
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/*  zjUQ]  
**FileAccess.java 9Rk(q4.OP  
*//文件访问(定位，写) >.qFhO\1so  
package NetFox; iLnW5yy  
import java.io.*; i?/Q7D<P  
Ln#o:"
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public class FileAccessI implements Serializable{ &`qYe)1Eo  
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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 Bb=r?;zjO  
RandomAccessFile oSavedFile; lf`ULY4{  
long nPos; t5E$u(&+'B  
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public FileAccessI() throws IOException
a Y)vi$;]  
{ %d+Fq=<  
this("",0); ^dpM2$J  
} w
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public FileAccessI(String sName,long nPos) throws IOException 1e[?}q]*  
{ x~5,v5R^]  
oSavedFile = new RandomAccessFile(sName,"rw"); qA '^b~  
this.nPos = nPos; V<9L-7X 8  
oSavedFile.seek(nPos); p-"C^=l  
} Qp<*or@  
"9xJ},:-  
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public synchronized int write(byte[] b,int nStart,int nLen) ]izHn;+  
{ )r.Wge  
int n = -1; m^oG9&";  
try{ Ze%S<xT!O  
oSavedFile.write(b,nStart,nLen); K ar!  
n = nLen; p1'q{E+o*  
} vT#R>0@mi  
catch(IOException e) q%G
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{ B5 /8LEWw  
e.printStackTrace (); "1gIR^S%9  
} Y!j/,FU  
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return n; gN}$$vS  
} p|gVIsg[-e  
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} [,Ul
 
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/* #om Gj&  
**SiteInfoBean.java M%:\ry4:  
*/ y"H5>  
package NetFox; K_+M?ap_  
iY`[dsT  
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public class SiteInfoBean { +On2R&m  
imADjBR]  
1CJ1-]S(3  
private String sSiteURL; //Site's URL
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private String sFilePath; //Saved File's Path z2V ->UK)  
private String sFileName; //Saved File's Name NCg("n,jx  
private int nSplitter; //Count of Splited Downloading File 2XyyU}.$  
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public SiteInfoBean() F lVG,Z  
{//nSplitter的缺省值为5 M5*Ln-qt(a  
//default value of nSplitter is 5 lFuW8G,-f@  
this("","","",5); w)<.v+u.
Y  
} )r
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15_"U+O(/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @8\0@[]  
{ v3[ZPc;;  
sSiteURL= sURL; W ~MNst?  
sFilePath = sPath; <>KQ8:  
sFileName = sName; +mG"m hF  
this.nSplitter = nSpiltter; T=w0T-[f  
j7);N  
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} GF@`~im  
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public String getSSiteURL() [6K[P3UZx  
{ 4NRj>
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return sSiteURL; E @r &K  
} Lwtp,.)pR  
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public void setSSiteURL(String value) "$5cKbJ  
{ QX?moW6UW  
sSiteURL = value; r+Sv(KS4i^  
} Xr o5~G  
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public String getSFilePath() on hLhrZ  
{ mb_6f:Qh3  
return sFilePath; DIYR8l}x  
} 9Pvv6WyKy  
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public void setSFilePath(String value) ,W'P8C  
{ ;<o?JM  
sFilePath = value; @@3NSKA  
} $2]>{g  
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public String getSFileName() 4<<eqxI$|  
{ Wf?[GO  
return sFileName; ?W dY{;&  
} :V6t5I'_  
?;w`hA3ei  
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public void setSFileName(String value) q(46v`u  
{ D @wIbU  
sFileName = value; %Ze7
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} WOgkv(5KN  
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Ei
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public int getNSplitter() Q4Wz5n1yp7  
{ mxH63$R  
return nSplitter; )C\/(  
} )`<&~>qp  
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public void setNSplitter(int nCount) =^zGn+@z  
{ Fv(FRZ)  
nSplitter = nCount; b5~p:f-&4B  
} iu0'[  
} I(3YXv VN  
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kTzO4s?  
/* [@pumH
>  
**Utility.java `S3)uV]I  
*/ Q
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package NetFox; zk@s#_3ct  
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public class Utility { 6c>:h)?  
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public Utility() ',D%,N}J  
{ pL*aU=FjQ  
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} )2^r 0(x  
j:8Pcx  
//线程睡眠 k8+U0J_{'  
public static void sleep(int nSecond) C%%gCPI^y  
{ sA+K?_  
try{ +~1
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Thread.sleep(nSecond); A58P$#)?  
} IW}Wt{'m  
catch(Exception e) @eESKg(,  
{ jW^]N$>  
e.printStackTrace (); .Y!dO@$:  
} 39pA:3iTd  
} Q7zpu/5?  
#<V5sgqS  
//日志 =|fB":vk  
public static void log(String sMsg) 6B b+f"  
{ roi,?B_8  
System.err.println(sMsg); 7
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} }QCn>LXE  
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public static void log(int sMsg) YoK )fh$  
{ 9B>P Qbs  
System.err.println(sMsg); }Q^*Zq9-  
} "2tKh!?Q  
} pI_:3D xe  
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/* J{5p4bkb  
**TestMethod.java }dU!PZ9N)  
*/ SY}"4=M?l  
package NetFox; $ \!OO)  
$&jVEMia  
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public class TestMethod { VTX6_&Hc1g  
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public TestMethod() _$8:\[J  
{ ///xx/weblogic60b2_win.exe z63
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try{ ra@CouR^c{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @'P
ay)P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `0+-:sXZ6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tu;Pm4q7  
fileFetch.start(); <a+@4d;  
} B<G,{k  
catch(Exception e){e.printStackTrace ();} p%#'`*<a_  
}P\6}
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} D mky!Cp
 
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public static void main(String[] args) P*ZMbAf.  
{ =L?2[a$2;  
new TestMethod(); ^oE#;aS  
} u2[L^]|  
} d+ [2Sm(7  
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