http断点续传简单实现（java)

/* f>4|>kS  
**SiteFileFetch.java %0/qb0N&  
*/ }' Y)"8AIA  
package NetFox; F.1
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import java.io.*; e?B}^Dk0i  
import java.net.*; C8T0=o/-`  
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public class SiteFileFetch extends Thread { S^==$TT  
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SiteInfoBean siteInfoBean = null; //文件信息Bean d6JW"  
long[] nStartPos; //开始位置 :FH&#Eq~4  
long[] nEndPos; //结束位置 rWDD$4y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 w3sU&  |N  
long nFileLength; //文件长度 aBG^Xhx  
boolean bFirst = true; //是否第一次取文件 hAc|a9 o  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 EU|IzUjFj|  
DataOutputStream output; //输出到文件的输出流 (S+/e5c)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EQd<!)HZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1ywdcg  
{ 19y,O0# _  
siteInfoBean = bean; xf,A<j(o  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Cc%{e9e*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @H4]Gp ]  
if(tmpFile.exists ()) G `!A#As  
{ b6Z3(!] ]  
bFirst = false; eiyr^Sch.  
read_nPos(); GI,TE  
} } S]!W\a  
else jn(!6\n"  
{ `sso Wn4  
nStartPos = new long[bean.getNSplitter()]; W}3%BWn  
nEndPos = new long[bean.getNSplitter()]; } eHxw+.  
} S$$SLy:P  
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} tvFe_*Ck  
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public void run() FJCORa@?_  
{ GK1nGdT]  
//获得文件长度 1;S?9N_B  
//分割文件 'v CMf  
//实例FileSplitterFetch & /T}  
//启动FileSplitterFetch线程 Y`eF9Im,  
//等待子线程返回 "!AtS  
try{ u%yYLpaKf  
if(bFirst) qGMU>J.;c  
{ 6k>5+-&_  
nFileLength = getFileSize(); PLz+%L;{  
if(nFileLength == -1) K\fD';  
{ uYg Q?*Z  
System.err.println("File Length is not known!"); 4 ?PB Fbd  
} PlS
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else if(nFileLength == -2) 2YY4 XHQS  
{ qpCaW0]7  
System.err.println("File is not access!"); aQ\SV0PI  
} h%W,O,K/  
else oQmXKV+[v  
{ 4K7ved)  
for(int i=0;i<nStartPos.length;i++) g}R Cjl4  
{ p_&B+ <z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9{j`eAUZl  
} lZ[J1:%  
for(int i=0;i<nEndPos.length-1;i++) |? fAe{*  
{ .xmB8 R  
nEndPos = nStartPos[i+1]; r2'K'?T3  
} w@Q~ax/  
nEndPos[nEndPos.length-1] = nFileLength; L?j<KW  
} <\Y(+?+uZ  
} 41Q)w=hoN  
Et(H6O8  
j nSZ@u  
//启动子线程 UYJ>L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +}?%w|8||s  
for(int i=0;i<nStartPos.length;i++) *C+[I  
{ ?Sa,n^b*H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gzSm=6Qw0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +6jGU'}[  
nStartPos,nEndPos,i); p!=8Pq.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t1m
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fileSplitterFetch.start(); u t4:L
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} Kg>B$fBx)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YlG#sBzl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MnF|'t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2}/r>]9^-  
nEndPos = " + nFileLength); - ry  
// fileSplitterFetch[nPos.length-1].start(); id : ^|  
4~$U#$u_  
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//等待子线程结束 5WRqeSGh  
//int count = 0; XP%_|Q2X  
//是否结束while循环 7_qsVhh]$E  
boolean breakWhile = false; .|07IH/Di{  
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while(!bStop) dz/fSA  
{ kv2o.q  
write_nPos(); {fl[BX]kZ  
Utility.sleep(500); \I4Uj.'>\  
breakWhile = true; W?E,"z  
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for(int i=0;i<nStartPos.length;i++) ~'0n ]Fw  
{ }b}jw.2Wu  
if(!fileSplitterFetch.bDownOver) 8$47Y2r@  
{ 4]0:zS*O  
breakWhile = false; >d]-X]  
break; -#/DK   
} a`^$xOK,  
} n[K%Xs)  
if(breakWhile) !.O[@A\.-  
break; K,|3?CjS  
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//count++; _4S
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//if(count>4) # .(f7~  
// siteStop(); lV4TFt,  
} 7SYe:^Dx  
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System.err.println("文件下载结束！"); 4h--x~ @  
} o_Y?s+~i[/  
catch(Exception e){e.printStackTrace ();} VZ`YbY  
} t!J>853  
I/A%3i=H  
mdrqX<x'~  
//获得文件长度 uTrzC+\aU  
public long getFileSize() aCQ[Uc<B:  
{ b3%a4Gg&  
int nFileLength = -1; )c9Xp:  
try{ uBg#zx  
URL url = new URL(siteInfoBean.getSSiteURL()); >Jn`RsuV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
lnjs{`^  
httpConnection.setRequestProperty("User-Agent","NetFox"); o(l%k},a  
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int responseCode=httpConnection.getResponseCode(); tCR~z1  
if(responseCode>=400) r<srTHGLo  
{ ^*$!9~  
processErrorCode(responseCode); *,O3@,+>H  
return -2; //-2 represent access is error 9lGa*f)  
} tlvZy+Blv  
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String sHeader; Bt$,=k  
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for(int i=1;;i++) Q7v1xBM  
{ #sjGju"#_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $kmY[FWu?  
//Utility.log(in.readLine()); 4o@:+T:1  
sHeader=httpConnection.getHeaderFieldKey(i); 811QpYA  
if(sHeader!=null) I D-I<Ev  
{ hDUU_.q)D  
if(sHeader.equals("Content-Length")) &1yErGXC  
{ Zj ^e8u=T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T<Zi67QC@  
break; 5i'?oXL  
} Ujvm|ml  
} :cXN Fu\C  
else X#ha*u~U  
break; *x p_#  
} 0ZI}eZA j  
} y>u|3:z  
catch(IOException e){e.printStackTrace ();} ,`a
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catch(Exception e){e.printStackTrace ();} Em{;l:;(W  
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Utility.log(nFileLength); eUR+j?5I  
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return nFileLength; a;~< iB;3"  
} /#eS3`48  
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//保存下载信息（文件指针位置） |90/tNe  
private void write_nPos() }>621L3 -  
{ +N2ILE8[<  
try{ la 0:jO5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); IFa~`Gf[  
output.writeInt(nStartPos.length); .s41Tc5u  
for(int i=0;i<nStartPos.length;i++) 1LvR,V<  
{ Rd]<591  
// output.writeLong(nPos); ]{+Y!tD  
output.writeLong(fileSplitterFetch.nStartPos); L %ifl:K  
output.writeLong(fileSplitterFetch.nEndPos); <W7WlT  
} unz~vG1Tn  
output.close(); xkSVD6Km  
} YG0b*QBY~  
catch(IOException e){e.printStackTrace ();} j*f\Z!EeZ  
catch(Exception e){e.printStackTrace ();} uXUuA/O5-  
} u%"5<ll  
;Kg7}4`I  
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//读取保存的下载信息（文件指针位置） /f+BeQ3#/  
private void read_nPos() hPgYKa8u  
{ L@Qvj-5e  
try{ ?pd/cj^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <~_XT>`y  
int nCount = input.readInt();
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nStartPos = new long[nCount]; e?O$`lf  
nEndPos = new long[nCount]; %i?v)EW  
for(int i=0;i<nStartPos.length;i++) -3b_}b
y  
{ j:2F97  
nStartPos = input.readLong(); eHd7fhW5  
nEndPos = input.readLong(); -GB,g=Dk  
} dShGIH?  
input.close(); D,=#SBJ:Z  
} /?T
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catch(IOException e){e.printStackTrace ();} ;AL:VU  
catch(Exception e){e.printStackTrace ();} Q~' \oWz  
} 2!b##`UjA7  
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private void processErrorCode(int nErrorCode) r/P}j4)b7  
{ `@0AGSzUv  
System.err.println("Error Code : " + nErrorCode); *ywr_9  
} ,zK E$  
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//停止文件下载 STg} Z  
public void siteStop()
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{ ;$4&Qp:#  
bStop = true; # M!1W5#  
for(int i=0;i<nStartPos.length;i++) 7+X~i@#rU  
fileSplitterFetch.splitterStop(); |}<Gz+E>  
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} JZ:yPvJ  
} <viC~=k;  
//负责部分文件的抓取 >XM]UdP  
**FileSplitterFetch.java I-Ut7W   
*/
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package NetFox; 42}8es.aa  
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import java.io.*; HGd
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import java.net.*; WNKP';(a@G  
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public class FileSplitterFetch extends Thread { 1_Av_X  
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String sURL; //File URL 0bIgOLP  
long nStartPos; //File Snippet Start Position Mk+G(4p  
long nEndPos; //File Snippet End Position +#<Z/  
int nThreadID; //Thread's ID SZR`uS  
boolean bDownOver = false; //Downing is over z%lJWvaA7  
boolean bStop = false; //Stop identical 2\T\p<_20  
FileAccessI fileAccessI = null; //File Access interface |z:4T%ES  
0?gHRdU"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e:C4f  
{ nf1 `)tXG  
this.sURL = sURL; {[L('MH2|  
this.nStartPos = nStart; 0!$y]Gr  
this.nEndPos = nEnd; 3 5L0CM  
nThreadID = id; n%4/@M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (-&d0a9N  
} +PKsiUJ|  
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public void run() S3E5^n\\  
{ $7i[7S4  
while(nStartPos < nEndPos && !bStop) 3Z&!zSK^  
{ <dr2 bz  
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try{ IvI..#EzG  
URL url = new URL(sURL); 4fjwC,,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X:g#&e_  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~(GNY5  
String sProperty = "bytes="+nStartPos+"-"; $b53~  
httpConnection.setRequestProperty("RANGE",sProperty); r`h".=oD
 
Utility.log(sProperty); F*>#Xr~/  
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InputStream input = httpConnection.getInputStream(); jF/S2Ty2  
//logResponseHead(httpConnection); 0 ]L  
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byte[] b = new byte[1024]; G'(rjH>q  
int nRead; ',LC!^:~Nw  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?#z<<FR  
{ hCd? Kti  
nStartPos += fileAccessI.write(b,0,nRead); eR6vO5to  
//if(nThreadID == 1) lCl5#L9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w&Gc#-B  
} }N$f=:i
I  
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Utility.log("Thread " + nThreadID + " is over!"); uKvdL "  
bDownOver = true; X;l/D}
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//nPos = fileAccessI.write (b,0,nRead); i*@PywT"i3  
} woBx609Aak  
catch(Exception e){e.printStackTrace ();} {P_7AM  
} Fkq^2o ]  
} _nxH
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%%>nM'4<  
//打印回应的头信息 $AE5n>ZD$  
public void logResponseHead(HttpURLConnection con) b(Tv
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{ (
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for(int i=1;;i++) M6Np!0G  
{ e"NP]_vh,  
String header=con.getHeaderFieldKey(i); #Nco|v  
if(header!=null) :2,NKdD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \hBzP^*"n  
Utility.log(header+" : "+con.getHeaderField(header)); ~dpf1fP  
else uZ\+{j=  
break;
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} .kPNWNrw  
} n\JI7A}  
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public void splitterStop() Q9xb7)G  
{ HTGLFY(&  
bStop = true; ~ A
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} @7C.0>W_A  
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} 1;V_E2?V  
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/* f
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**FileAccess.java >][D"  
*//文件访问(定位，写) 0< vJ*z|_  
package NetFox; !Hl]&  
import java.io.*; l!&ik9m  
9!W$S[ABRB  
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public class FileAccessI implements Serializable{ &r4|WM/ec  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ::$W .!Uv  
RandomAccessFile oSavedFile; Y_!+Y<x7v  
long nPos; Y68A+ B.  
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public FileAccessI() throws IOException m|{^T/kIbQ  
{ #5z0~Mg-X  
this("",0); GJrmK  
} :/$WeAg  
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public FileAccessI(String sName,long nPos) throws IOException 9 i/ (  
{ |l+5E   
oSavedFile = new RandomAccessFile(sName,"rw"); 8B?U\cfa^  
this.nPos = nPos; ~~-VScG&  
oSavedFile.seek(nPos); ftR& 5!Wm  
} =&$z Nc4h  
c3g`k"3*`  
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public synchronized int write(byte[] b,int nStart,int nLen) %'2.9dB  
{ 7H< IO`  
int n = -1; *URT-+'  
try{ tzIP4CR~F&  
oSavedFile.write(b,nStart,nLen); 111A e*U  
n = nLen; 5:f!EMb  
} 4^bt~{}  
catch(IOException e) f'@ L|&w  
{
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e.printStackTrace (); PE4 L7  
} M>p<1`t-&  
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return n; >L2_k'uE+;  
} SM4`Hys;p  
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} b(;u2 8  
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/* 2*z~'i  
**SiteInfoBean.java uMZ~[Sz  
*/ <%S)6cw(3  
package NetFox; 3J &Ros  
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public class SiteInfoBean { Z,E
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private String sSiteURL; //Site's URL . c+m(Pk  
private String sFilePath; //Saved File's Path 0ck3II  
private String sFileName; //Saved File's Name }" vxYB!h3  
private int nSplitter; //Count of Splited Downloading File Qa )+Tv  
2WFZ6  
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public SiteInfoBean() =N\; ?eF(  
{//nSplitter的缺省值为5 D48e30  
//default value of nSplitter is 5 ?8"*B^*Sh  
this("","","",5); X%IqZ{{  
} -GPJ,S V>  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) v4"Ukv  
{ C:t>u..  
sSiteURL= sURL; #[{{&sN  
sFilePath = sPath; &
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sFileName = sName; rBTg"^jsw  
this.nSplitter = nSpiltter; X_o#!  
m.Zy$SDj(  
y2#>a8SRS  
} nJN-U+)u  
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public String getSSiteURL() z0<
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{ nZ(]WPIN"  
return sSiteURL; CE`]
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} .s*N1 U?h  
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public void setSSiteURL(String value) /x ?@Mn>  
{ fe/;U=te  
sSiteURL = value; .b3h?R*&  
} JVX)>2&$  
8O'bCBhv  
>80k5$t  
public String getSFilePath() : x&R'wX-  
{ Gc`PO  
return sFilePath; W<X3!zuKSg  
} )tI^2p{  
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public void setSFilePath(String value) \+R%KA/F  
{ :$b`n  
sFilePath = value; vF$( Y/  
} N<:c*X  
]|CcQ1#|H  
@-dGZ5  
public String getSFileName() ,^?g\&f(  
{ qhxMO[f  
return sFileName; hi!A9T3%}M  
} ;^xM" {G8  
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public void setSFileName(String value) HRyFjAR\?  
{ V ,p~,rC  
sFileName = value; ^Qx?)(@  
} U3a
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1,+<|c)T?  
public int getNSplitter() gD6S%O  
{ a
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return nSplitter; p6<JpW5@_  
} (NLw#)?  
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public void setNSplitter(int nCount) YQN:&Cls  
{ E,6|-V;?  
nSplitter = nCount; $M)i]ekm  
} _,L_H[FN  
} &6vaLx  
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/* 7?whxi Qs  
**Utility.java -4Hb]#*2  
*/ Q0R05*  
package NetFox; MWv@]P_0p!  
a -Pz<*  
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public class Utility { ) 1AAL0F\B  
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tC'E#2  
public Utility() BwWSztJ+B  
{ MTtx|L\4  
)%@7tx  
%JE>Z]  
} xkDK5&V  
\PxT47[@e  
//线程睡眠 i`gM> q&  
public static void sleep(int nSecond) <4Gy~?  
{ Nf)YG!  
try{ v=@y7P1  
Thread.sleep(nSecond); ^_ch%3}Im  
} GFdbwn5B  
catch(Exception e) -fPiHKJ  
{ * |,N/e  
e.printStackTrace (); ^yPZ$Q  
} >*{k~Y-G  
} VBL4cU8D  
wmGcXBHt$  
//日志 T<0r,  
public static void log(String sMsg) HQP.7.w7 5  
{ We{@0K/O
 
System.err.println(sMsg); M
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} G*N[tw  
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j$q5m 24L  
public static void log(int sMsg) ~wDXjn"U&  
{ &NBH'Rt  
System.err.println(sMsg); BEaF-*?A  
} @??3d9I  
} _!o8s%9be  
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/3aW 0/^o  
/* o9e8Oj&  
**TestMethod.java T9V=#+8#"  
*/ Bn]=T  
package NetFox; E_=F'sP?  
jXeE]A"  
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public class TestMethod { .1[.f}g$J  
'{2]:  
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public TestMethod() {d[Nc,AMb  
{ ///xx/weblogic60b2_win.exe g}0K@z3  
try{ @
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); VP A+/5TW  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9\.0v{&v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); eI:[o  
fileFetch.start(); f/J/tt  
} ,7j8+p|},  
catch(Exception e){e.printStackTrace ();} G~5pMyOR  
$L= Dky7  
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} l48$8Mgrr  
"/6#Z>y  
}%Mdf6LS64  
public static void main(String[] args) AT1cN1:4?  
{ R/v|ZvI  
new TestMethod(); zTcz+3x  
} veq3t$sj  
} A8&@Vxdz  
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