http断点续传简单实现（java)

/* l'VgS:NT  
**SiteFileFetch.java zGu(y@o  
*/ fEdQR->  
package NetFox; FZnkQ  
import java.io.*; O: sj
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import java.net.*; LGPy>,!  
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public class SiteFileFetch extends Thread { $GUSTV  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \i "I1xU  
long[] nStartPos; //开始位置 R5G~A{w0  
long[] nEndPos; //结束位置 )__vPPko i  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F$ x@]  
long nFileLength; //文件长度 &Hc8u,|  
boolean bFirst = true; //是否第一次取文件 bc5+}&W  
boolean bStop = false; //停止标志 ";9cYoKRY  
File tmpFile; //文件下载的临时信息 +}>whyX1  
DataOutputStream output; //输出到文件的输出流 ?{$Q'c_I  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） U}6'_ PRQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException /9|1eSUa  
{ )dG7$,g  
siteInfoBean = bean; ,m!j2H}8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); R*E/E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H]Q Z4(  
if(tmpFile.exists ()) \rcbt6H  
{ NyJU?^f&v  
bFirst = false; Q}W6?XDu  
read_nPos(); 18Pc4~>0  
} IO`.]iG  
else >f19P+  
{ 57)S"  
nStartPos = new long[bean.getNSplitter()]; s7S
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nEndPos = new long[bean.getNSplitter()]; $uawQf+S  
} 8N!E`{W  
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} J+[&:]=P  
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public void run() De4UGX  
{ 4t|g G`QW7  
//获得文件长度 ,`G8U/  
//分割文件 
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//实例FileSplitterFetch i15uHl  
//启动FileSplitterFetch线程 ,JN2q]QPP  
//等待子线程返回 fg%I?ou  
try{ "QA#  
if(bFirst)
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{ IBf&'/ 8\  
nFileLength = getFileSize(); ln'7kg
 
if(nFileLength == -1) &'N{v@Oi)  
{ d%81}4f:  
System.err.println("File Length is not known!"); CwTx7 ^qa  
} <O?iJ=$  
else if(nFileLength == -2) ZBcZG  
{ m-dne/%_  
System.err.println("File is not access!"); @ _U]U  
} J8J~$DU\Gv  
else iRS )Z)  
{ ?zQ\u{]=  
for(int i=0;i<nStartPos.length;i++) n wToZxHZ~  
{ >,y291p2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); W@`Nn*S  
} IBcCbNs!  
for(int i=0;i<nEndPos.length-1;i++) ~{0:`)2FQ  
{ 4Ucg<Z&%  
nEndPos = nStartPos[i+1];
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} '49&qO5B  
nEndPos[nEndPos.length-1] = nFileLength; 7qA0bUee5  
} nY'0*:'u  
} 1<fS&)^W  
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\
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//启动子线程 x:88
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yN5g]U.Q  
for(int i=0;i<nStartPos.length;i++) 4cRF3$amd  
{ wP/&k`HQ#i  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'LpJ:Th  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), tlV>  
nStartPos,nEndPos,i); 7u6o~(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ha1E /b]K  
fileSplitterFetch.start(); 84DneSpHsp  
} ZvpcjP  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sczN0*w&C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,u#uk7V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =GL}\I  
nEndPos = " + nFileLength); }\:3}'S.$  
// fileSplitterFetch[nPos.length-1].start(); xKWqDt  
2xhwi.u  
HlqCL1\<  
//等待子线程结束 \-0@9E<D  
//int count = 0; `L`qR,R  
//是否结束while循环 sD7Qt  
boolean breakWhile = false; ;3U-ghj  
#M$[C d I$  
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while(!bStop) -ZlBg~E  
{ "yCCei,hA?  
write_nPos(); NEa:  
Utility.sleep(500); =dHM)OXD"  
breakWhile = true; d=o|)kV  
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for(int i=0;i<nStartPos.length;i++) $HF. 0
2{|  
{ ;o8C(5xE|  
if(!fileSplitterFetch.bDownOver) ,=O`'l>K  
{ dFS>uIT7X  
breakWhile = false; +(x^5~QX  
break; O%H_._#N`  
} cTCo~Pk4  
} MIo<sJuv  
if(breakWhile) n1 =B  
break;
q&Y'zyHLP  
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;n%SjQ'%  
//count++; 8>x!n/z)
 
//if(count>4) nBI?~hkP3  
// siteStop(); u=z$**M^  
} :6S!1roi  
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System.err.println("文件下载结束！"); a|SgGtBtT4  
} Rq )&v*=  
catch(Exception e){e.printStackTrace ();} QG*=N {%5  
} t.$3?"60~  
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//获得文件长度 dF:@BEo  
public long getFileSize() GwQW I]  
{ C8rD54A'M  
int nFileLength = -1; /:3:Ky3  
try{ ye:pGa w  
URL url = new URL(siteInfoBean.getSSiteURL()); rZ2X$FO@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FRd!UqMXY  
httpConnection.setRequestProperty("User-Agent","NetFox"); T6h-E^Z  
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|t+M/C0y/  
int responseCode=httpConnection.getResponseCode(); _BO:~x  
if(responseCode>=400) ZQXv
-"  
{ 1j0OV9-|  
processErrorCode(responseCode); Zt4g G KG  
return -2; //-2 represent access is error 3I&=1o  
} ?%% 'GX  
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String sHeader; >/mi#Y6  
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for(int i=1;;i++) hr_ 5D  
{ aDmyr_f$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Wt4ROj  
//Utility.log(in.readLine()); Gdmh#pv  
sHeader=httpConnection.getHeaderFieldKey(i); T6m#sVq  
if(sHeader!=null) ,@kD9n5
#  
{ 1^XuH('  
if(sHeader.equals("Content-Length")) Yv k Qh{  
{ d~F`q7F'?]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^`~M f  
break; 2_M+akqy^  
} rqW[B/a{  
} Ls{z5*<FM  
else z%$ E6Im  
break; oFM\L^Y?$$  
} oNQ;9&Z,^2  
} wgfA\7Z  
catch(IOException e){e.printStackTrace ();} R,R[.2Vi  
catch(Exception e){e.printStackTrace ();} (;v)0&h  
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Utility.log(nFileLength); U/F<r3.`#  
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return nFileLength; 6(awO2{BP  
} **_`AM~  
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//保存下载信息（文件指针位置） t\~lGG-p  
private void write_nPos() ddvSi6  
{ pYZ6-s  
try{ Q
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output = new DataOutputStream(new FileOutputStream(tmpFile)); Atl`J.;G  
output.writeInt(nStartPos.length); :W]?6=  
for(int i=0;i<nStartPos.length;i++) !`=ms1%U  
{ e9e%
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// output.writeLong(nPos); KiW4>@tY  
output.writeLong(fileSplitterFetch.nStartPos); #:C;VAAp  
output.writeLong(fileSplitterFetch.nEndPos); ASmMj;>UM  
} <"A|Xv'Q  
output.close(); ~f=~tN)hZ  
} jJFWPD]u  
catch(IOException e){e.printStackTrace ();} <i{O\K]9  
catch(Exception e){e.printStackTrace ();} N<lejZ}!q  
}  o&uO]  
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//读取保存的下载信息（文件指针位置） 'F%4[3a$\n  
private void read_nPos() h4rIt3`  
{ vvA=:J4/i)  
try{ 3ThBy'
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0
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int nCount = input.readInt(); } 8ZCWmd  
nStartPos = new long[nCount]; ].F
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nEndPos = new long[nCount]; @_"B0$,-i  
for(int i=0;i<nStartPos.length;i++) :#D?b.=  
{ Vp8t8X1`  
nStartPos = input.readLong(); }s)MDq9  
nEndPos = input.readLong(); J)1:jieQ  
} ~^d. zIN!  
input.close(); r/v'h@  
} <;O=h; ~|  
catch(IOException e){e.printStackTrace ();} ]=\Mf<  
catch(Exception e){e.printStackTrace ();} P^m+SAAB  
} z'@j9vT  
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private void processErrorCode(int nErrorCode) 3t<XbHF9  
{ U'^AJ2L8  
System.err.println("Error Code : " + nErrorCode); +5J"G/f  
} E)==!T@E  
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\b{Aj,6,  
//停止文件下载 u I$|M  
public void siteStop() OLXkiesK{  
{ 
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bStop = true; $=dp)  
for(int i=0;i<nStartPos.length;i++) V]b1cDx{  
fileSplitterFetch.splitterStop(); &<I*;z6%t  
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} csn/h$`-@  
} xlPUum-o  
//负责部分文件的抓取 TDI8L\rr  
**FileSplitterFetch.java wMy$T<:   
*/ m"Y;GzqQl  
package NetFox; .C^1.)  
&
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import java.io.*; z;1y7W!v  
import java.net.*; =Y`P}vI]w%  
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public class FileSplitterFetch extends Thread { .DSn H6O  
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[6x-c;H_4  
String sURL; //File URL 0_yE74i  
long nStartPos; //File Snippet Start Position dz/' m7  
long nEndPos; //File Snippet End Position @|Z:7n6S  
int nThreadID; //Thread's ID :xw2\:5~0  
boolean bDownOver = false; //Downing is over Ov3W;jD  
boolean bStop = false; //Stop identical 34VyR a  
FileAccessI fileAccessI = null; //File Access interface -q7A\8C  
O+;0|4V%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException hoxn!x$?  
{ {zoUU  
this.sURL = sURL; b i^h&H  
this.nStartPos = nStart; _`lj 3Lm0>  
this.nEndPos = nEnd; u2HkAPhD  
nThreadID = id; pAS!;t=n,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9xWC<i  
} KDwz!:ye  
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public void run() -_=0PW5{  
{ MLg<YL  
while(nStartPos < nEndPos && !bStop) pT]M]/y/:  
{ L(!4e  
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fr'M)ox1  
try{ UnNvlkjq9  
URL url = new URL(sURL); )#-27Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <*L=u;  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7L)1mB.  
String sProperty = "bytes="+nStartPos+"-"; tB.;T0n  
httpConnection.setRequestProperty("RANGE",sProperty); mhT
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Utility.log(sProperty); ZK5(_qW&i  
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}aYm86C]  
InputStream input = httpConnection.getInputStream(); 9@AGx<S1  
//logResponseHead(httpConnection); MhC74G  
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byte[] b = new byte[1024]; .d`+#1Ot(  
int nRead; T=cSTS!P;q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Rf@D]+v  
{ $,08y   
nStartPos += fileAccessI.write(b,0,nRead); \V@SCA'  
//if(nThreadID == 1) :QgC Zq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Mq) n=M  
} R_h(Z{d  
\C.%S +u  
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Utility.log("Thread " + nThreadID + " is over!"); /H.QGPr  
bDownOver = true; PK1j$&F  
//nPos = fileAccessI.write (b,0,nRead); hT6:7_UD  
} *ggTTHy
 
catch(Exception e){e.printStackTrace ();} 3ojK2F(1D  
} J#Fe"  
} }]vj"!?a  
}@yvw*c  
+C7 1".i-  
//打印回应的头信息 w?ssV  
public void logResponseHead(HttpURLConnection con) IV
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{ dsD
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for(int i=1;;i++) q3Umqvl)oe  
{ G],+?E_,  
String header=con.getHeaderFieldKey(i); O<4i)Lx2  
if(header!=null) 2>Kq)Ii  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 475yX-A  
Utility.log(header+" : "+con.getHeaderField(header));  N>`+{  
else "M6a_rZ2W  
break; EZ #UdK_  
} Y0B
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} hM E|=\  
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public void splitterStop() n? "ti  
{ .G+}Kn9!  
bStop = true; ~l!(I-'?g  
} o^RdVSkU;  
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,  
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} ]6OrL TmP  
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/* HY#7Ctn3  
**FileAccess.java zcJ]US  
*//文件访问(定位，写) G_5sF|(mq  
package NetFox; OxElvbM#  
import java.io.*; +C;ZO6%w  
)|LX_kyW  
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public class FileAccessI implements Serializable{ 9BI5qHEp  
4 E3@O  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0vG}c5;F  
RandomAccessFile oSavedFile; {+c/$4<  
long nPos; )$q<"t\#P#  
1E$
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public FileAccessI() throws IOException qU8UKIP  
{ 6uDA{[OH  
this("",0); f<SSg*A;  
} x+B~t4A  
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public FileAccessI(String sName,long nPos) throws IOException JmNeqpbB`w  
{ @usQ*k  
oSavedFile = new RandomAccessFile(sName,"rw"); +azPpGZ=  
this.nPos = nPos; PB>p"[ap4  
oSavedFile.seek(nPos); W/oRt<:E  
} N(vbo  
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public synchronized int write(byte[] b,int nStart,int nLen) {\|? {8f  
{ u-U
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int n = -1; ?^BsR  
try{ 1@)]+* F*z  
oSavedFile.write(b,nStart,nLen); gbpm::  
n = nLen; k6JB%m\E  
} 8e\a_R*(|  
catch(IOException e) k`g+  
{ ]kb%l"&  
e.printStackTrace (); vzi=[A  
} &8"a7$  
^\N2 Iu>6  
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return n; ^%_B'X9  
} 8YkP57Y%[Z  
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} L*FmJ{Yf  
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/* 6FEtq,;0w  
**SiteInfoBean.java /oiAAB27  
*/ JS(KCY9  
package NetFox; YD@V2gK  
tB(Q-c  
!c6lP'U  
public class SiteInfoBean { 1<\cMY6  
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czMLvPXRx  
private String sSiteURL; //Site's URL bSz6O/A/  
private String sFilePath; //Saved File's Path LV8,nTYvE  
private String sFileName; //Saved File's Name d,<ctd  
private int nSplitter; //Count of Splited Downloading File !LIWoa[ F.  
asQ" |]m  
w-/bLg[L?$  
public SiteInfoBean() S\0"G*  
{//nSplitter的缺省值为5 :\80*[=;Z  
//default value of nSplitter is 5 yrsP'th  
this("","","",5); _9n.ir5YX  
} u x:,io
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?rBj{]=  
{ 8(3vNuyP  
sSiteURL= sURL; uU5:,Wy+dg  
sFilePath = sPath; `dL9sfj>  
sFileName = sName; E/U1g4S  
this.nSplitter = nSpiltter; t:=Ui/!q  
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Kq{s^G  
} f7s]:n*Ih  
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]-* }-j`  
public String getSSiteURL() O)9T|, U  
{ ?R,^prW{  
return sSiteURL; fd+
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} {ReAl_Cm  
|AFF*]e S  
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public void setSSiteURL(String value) H>M%5bj  
{ (^Nf;E  
sSiteURL = value; &q":o 'q  
} tAc;O[L  
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public String getSFilePath() i}wu+<Mk  
{ hJd#Gc~*M  
return sFilePath; :nwcO3~`  
} GuDus2#+  
}1_gemlf  
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public void setSFilePath(String value) d9Q%GG0]  
{ 3[V|C=u0  
sFilePath = value; 3Ji,n;QLm  
} !/jx4w~R  
\!SC;  
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public String getSFileName() r`S]`&#}(  
{ vxqMo9T  
return sFileName; Szg<;._J  
} #Jm_~k  
k*-+@U"+  
Hfc^<q4a.  
public void setSFileName(String value) {qx"/;3V  
{
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sFileName = value; .IKK.G  
} " g_\W  
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public int getNSplitter() we} sC,  
{ ;bA
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return nSplitter; {Ua5bSbh  
} {X"X.`p  
8"<!
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public void setNSplitter(int nCount) N`zHe*=[~  
{ g:2/!tujL  
nSplitter = nCount; 
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} Zy!\=-dSm  
} ~Yr.0i.W  
(>8fcQUBb  
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/* IsRsjhg8x  
**Utility.java /4T%&#6s  
*/ [j
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package NetFox; <v2R6cj5  
i5AhF\7F9  
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public class Utility { >K &b,o,[  
'.d
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public Utility() ar^`r!ABEh  
{ $K,aLcu  
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} |QzPY8B9O  
nB:Bw8U"Q  
//线程睡眠 tjTF?>^6|  
public static void sleep(int nSecond) [2FXs52  
{ )Tb
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try{ pD>3c9J'^F  
Thread.sleep(nSecond); J`x9XWYw  
} %2L9kw'  
catch(Exception e) }BfwMq4E)n  
{ aSK$#Xeu  
e.printStackTrace (); ##n\9ipD  
} IcIMa  
} ZtvU~'Q  
@eMyq1ZU  
//日志 *Zc-&Dk:Ir  
public static void log(String sMsg) J`V6zGgW  
{ %(e=Q^=  
System.err.println(sMsg); ;{ezK8FJ}@  
} HwGtLeB"  
jxoEOEA  
9z-"JnM  
public static void log(int sMsg) pTN_6=Y"  
{ zCQv:.0L  
System.err.println(sMsg); *o>E{  
} B#gmT2L  
} es6e-y@e  
pE`(kD  
\UC4ai2MK  
/* `C()H@;  
**TestMethod.java gTq-\k
(  
*/ +amvQ];?Q8  
package NetFox; awawq9)Y  
*PI3
L/*  
^Uf`w7"iY  
public class TestMethod { O7K))w  
vd;wQ  
_AO0:&  
public TestMethod() lu{}j4  
{ ///xx/weblogic60b2_win.exe :#LB}=HQ  
try{ dHu]wog  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !uZ+r%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]MHQ"E?
  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &B.r&K&  
fileFetch.start(); dn5v|[dJ  
} q{@Wn]!k  
catch(Exception e){e.printStackTrace ();} s R~&S))  
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} F+6ZD5/  
E`
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public static void main(String[] args) L fi]s  
{ }
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new TestMethod(); tyDtwV|  
} )CmuC@ Q"  
} m0edkt-x  
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