http断点续传简单实现（java)

/* (wY%$kW4  
**SiteFileFetch.java =0]Mc$Ih  
*/ 1[Mr
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package NetFox; Nm081ic2<  
import java.io.*; v S+~4Q41  
import java.net.*; +`4}bc,G  
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public class SiteFileFetch extends Thread { i ('EBO  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &S-& 'ZAY  
long[] nStartPos; //开始位置 E8dp  
long[] nEndPos; //结束位置 IGqmH=-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 88*RlxU  
long nFileLength; //文件长度 !S-hv1bE  
boolean bFirst = true; //是否第一次取文件 V_1
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boolean bStop = false; //停止标志 y-X'eCUz  
File tmpFile; //文件下载的临时信息 Yptsq@s  
DataOutputStream output; //输出到文件的输出流  !fV6KkV  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \9?<E[  
public SiteFileFetch(SiteInfoBean bean) throws IOException V$_0VN'+Z  
{ .5ycO  
siteInfoBean = bean; #~f+F0#%?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jlP7'xt1%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ).S<{zm7  
if(tmpFile.exists ()) .
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{ 9M=K@a  
bFirst = false; (qP$I:Q4]v  
read_nPos(); (j I|F-i  
} yk)j;i4@  
else `;qZ$HH  
{ 3# (5Kco
 
nStartPos = new long[bean.getNSplitter()]; c>
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nEndPos = new long[bean.getNSplitter()]; Ny'v/+nQ  
} eC{Z  
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} Rqz
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public void run() eM"mP&TTL  
{ <^_?hN8.  
//获得文件长度 sZB6zTX J  
//分割文件 S:uEK  
//实例FileSplitterFetch -c?wEqa~2  
//启动FileSplitterFetch线程 zn!  
//等待子线程返回 @R&D["!  
try{ EM/+1 _u  
if(bFirst) [\ YP8^..  
{ 'uzv\[  
nFileLength = getFileSize(); F s\P/YX  
if(nFileLength == -1) hUxhYOp  
{ DOIWhd5:  
System.err.println("File Length is not known!"); ejY5n2V#=  
} $)]FCuv  
else if(nFileLength == -2) ~&3"Mi&>`  
{ Le JlTWotC  
System.err.println("File is not access!"); R<-C>D  
} 7NC8<o;  
else aQ:f"0fL  
{ &:#8ol(n5b  
for(int i=0;i<nStartPos.length;i++) |I5?5 J\  
{ Q_.c~I}yV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5l/l]  
} pNQkKDbL+  
for(int i=0;i<nEndPos.length-1;i++) o>-v?Ug  
{ @h$0S+?:  
nEndPos = nStartPos[i+1]; *b{lL5  
} {4aY}= -Q*  
nEndPos[nEndPos.length-1] = nFileLength; Sw@,<4S  
} I*S`I|{J  
} Z"|P(]A  
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//启动子线程 K!c@aD:#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Cj 2Xl  
for(int i=0;i<nStartPos.length;i++) q;zf|'&*7C  
{ ![]I%'s  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "5JN
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0s9z @>2  
nStartPos,nEndPos,i); =&VXn{e  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,Zf!KQw  
fileSplitterFetch.start(); 2C]la  
} ?wf+{x-dPP  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }`N2ZxC0AQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); kTZx-7~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G68Nv:  
nEndPos = " + nFileLength); .`&/QiD  
// fileSplitterFetch[nPos.length-1].start(); :6j :9lYL2  
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//等待子线程结束 ^_KD&%M6  
//int count = 0; CTkN8{2S  
//是否结束while循环 G(0y|Eq  
boolean breakWhile = false; I>%S4Z+o  
LJ(n?/z%  
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while(!bStop) Lkl|4L  
{ L=HVdeE  
write_nPos(); >U~|R=*  
Utility.sleep(500); [+l  
breakWhile = true; q|u8CX  
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for(int i=0;i<nStartPos.length;i++) W8,tl>(  
{ crNjI`%tw  
if(!fileSplitterFetch.bDownOver) .^LL9{?  
{ &oeN#5Es8C  
breakWhile = false; W
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break; YXzZ-28,<  
} !rXcGj(k  
} )t,{YGY#  
if(breakWhile) :G`L3E&1s  
break; ^'7C0ps+A  
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//count++; d=?Mj]  
//if(count>4) i$bzdc#s  
// siteStop(); 9si}WqAw  
} =a9etF%B  
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System.err.println("文件下载结束！"); If-,c^i  
} -MrtliepW*  
catch(Exception e){e.printStackTrace ();} v\%B  
} /^'Bgnez  
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//获得文件长度 \L ]   
public long getFileSize() _r\$NgJIM  
{ z
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int nFileLength = -1; ou'~{-_xd  
try{ 2$ |]Vj*Zs  
URL url = new URL(siteInfoBean.getSSiteURL()); 5iQmZ[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j0iAU1~_VX  
httpConnection.setRequestProperty("User-Agent","NetFox"); `ke3+%uj o  
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int responseCode=httpConnection.getResponseCode(); BT
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if(responseCode>=400) p^1zIC>F  
{ g@~!kh,TH  
processErrorCode(responseCode); UvxSMD:A  
return -2; //-2 represent access is error SyK9Is{8  
} 2W^B{ZS;  
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String sHeader; >
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for(int i=1;;i++) {p`mfEE(  
{ mC i[Ps  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); t;8\fIW5  
//Utility.log(in.readLine()); 9>by~4An?  
sHeader=httpConnection.getHeaderFieldKey(i); LY]nl3{E  
if(sHeader!=null) UJz#QkAio  
{ 2_;]  
if(sHeader.equals("Content-Length")) qib7Z]j  
{ mxQR4"]jY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6M ^IwE  
break; ao#!7F  
} t5.`!3EO  
} N&T:Lt_N  
else zfhTc=(/  
break; 8-7dokg>  
} #HeM,;Xp  
} }N3V
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catch(IOException e){e.printStackTrace ();} dY}pN"  
catch(Exception e){e.printStackTrace ();} ,c>N}*6h=W  
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Utility.log(nFileLength); mjb{~  
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return nFileLength; WsR+Np@c  
} `
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//保存下载信息（文件指针位置）
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private void write_nPos() Ln.9|9  
{ YOyp|%!  
try{ #'@ilk/.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); DkgUvn/S  
output.writeInt(nStartPos.length); %}q.cV  
for(int i=0;i<nStartPos.length;i++) )MZC>
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{ A\z`c e!  
// output.writeLong(nPos); 8eluO ?p  
output.writeLong(fileSplitterFetch.nStartPos); -v+&pG?m  
output.writeLong(fileSplitterFetch.nEndPos); `>6T&  
} ['cz;2{:W  
output.close(); 5 L/x-i  
} L@RIZu>ZW+  
catch(IOException e){e.printStackTrace ();} !KcWH9  
catch(Exception e){e.printStackTrace ();}  G2`${aMS  
} }`xdWY  
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//读取保存的下载信息（文件指针位置） h[kU<mU"T  
private void read_nPos() qP3q  
{ F";.6%;AC  
try{ gl{B=NN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hmpr%(c`  
int nCount = input.readInt(); n[,XU|2  
nStartPos = new long[nCount]; +m)q%I>  
nEndPos = new long[nCount]; 1@>$ Gcc  
for(int i=0;i<nStartPos.length;i++) Y9Z]i$qS&k  
{ ve Tx, \6@  
nStartPos = input.readLong(); A
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nEndPos = input.readLong(); X|}2_B  
} 6cz/n8Mg  
input.close(); B
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} =wVJ%  
catch(IOException e){e.printStackTrace ();} AiP!hw/V$  
catch(Exception e){e.printStackTrace ();} x
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} x|i_P|Z  
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private void processErrorCode(int nErrorCode)
)1 m">s4  
{ E5</h"1  
System.err.println("Error Code : " + nErrorCode); &c>?~-!W  
} MSw$_d  
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v+G=E2Lh
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//停止文件下载 );FS7R  
public void siteStop() wSEWwU[  
{ *JX;|S  
bStop = true; k*?I>%^6#T  
for(int i=0;i<nStartPos.length;i++) nXy>7H[0  
fileSplitterFetch.splitterStop(); q?):oJ  
[
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} cxIk<&i~(  
} ]bZ(HC?KZr  
//负责部分文件的抓取 *.#oxcll  
**FileSplitterFetch.java gNYqAUG5  
*/ bD^b  
package NetFox; Hc^W%t~  
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import java.io.*; n_?tN\M  
import java.net.*; 6eFp8bANN#  
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public class FileSplitterFetch extends Thread { _>+8og/%@  
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String sURL; //File URL 9KWuN:Sg  
long nStartPos; //File Snippet Start Position eI45PMP  
long nEndPos; //File Snippet End Position AN!s{7V3  
int nThreadID; //Thread's ID FMA6_fju4  
boolean bDownOver = false; //Downing is over Q7Iw[=;\  
boolean bStop = false; //Stop identical [AMAa]^  
FileAccessI fileAccessI = null; //File Access interface  ]^'@[<  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .p0Clr!  
{ *g?Po+ef%  
this.sURL = sURL; *Kdda} J+  
this.nStartPos = nStart; (hiyNMC
  
this.nEndPos = nEnd; '5&s=M_  
nThreadID = id; ^nbnbU4'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 T,aW8|  
} y@0E[/O  
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public void run() {~Rk2:gx  
{ $Y69@s%f  
while(nStartPos < nEndPos && !bStop) 3EJt%}V$k  
{ % qV 6  
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try{ :Nofp&  
URL url = new URL(sURL); ``wS
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bv&;R  
httpConnection.setRequestProperty("User-Agent","NetFox"); B95B|tU>.  
String sProperty = "bytes="+nStartPos+"-"; ZYC<Wb)I  
httpConnection.setRequestProperty("RANGE",sProperty); yUpgoX(6  
Utility.log(sProperty); Q~Hy%M%R3  
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7(pF[LCF  
InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection); 4^M  
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byte[] b = new byte[1024]; rk #sy$  
int nRead; gHo?[pS%y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) HS
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{ xL\0B,]  
nStartPos += fileAccessI.write(b,0,nRead); DQr Y*nH  
//if(nThreadID == 1) [PDNwh0g5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0N$v"uX@  
} }hhGu\  
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Utility.log("Thread " + nThreadID + " is over!"); LU={")TdQ  
bDownOver = true; 4rLL[??  
//nPos = fileAccessI.write (b,0,nRead); G|!on<l&  
} B!?%O  
catch(Exception e){e.printStackTrace ();} 8|\8O@  
} V6@o]*  
} >s<^M|S07  
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//打印回应的头信息 gcl5jB5)>  
public void logResponseHead(HttpURLConnection con) $xPaYf  
{ ~kEI4}O  
for(int i=1;;i++) z?R|Ok  
{ M 0U0;QJ  
String header=con.getHeaderFieldKey(i); J^Wa8Q;9lX  
if(header!=null) )QU  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?fi,ifp*|l  
Utility.log(header+" : "+con.getHeaderField(header)); dtRwTUMe?  
else n<z[J=I  
break; `xqr{lhL  
} qKr8)}h  
} n'E(y)9|  
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public void splitterStop() Lh!J >  
{ @1o/0y"  
bStop = true; ! |<Fo'U  
} 5YeM%%-S  
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} ^:^9l1]  
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/* A$Hfr8w1u  
**FileAccess.java s(/;U2"e  
*//文件访问(定位，写) $P/~rZ@M@  
package NetFox; hKL4cpK4  
import java.io.*; MyJ%`@+1  
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8  
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public class FileAccessI implements Serializable{ lb4Pcdj  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 I_}SB|  
RandomAccessFile oSavedFile; EE&K0<?T|:  
long nPos; riY~%9iV'  
"l3_=Gua  
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public FileAccessI() throws IOException U)fc*s  
{ !/'t5~x[  
this("",0); h7G"G"  
} @ym v< Mo  
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public FileAccessI(String sName,long nPos) throws IOException -$,TMqM  
{ +~m46eI  
oSavedFile = new RandomAccessFile(sName,"rw"); I8
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this.nPos = nPos; AifWf2$S  
oSavedFile.seek(nPos); LiN$ pwm  
} 'f!8DGix  
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public synchronized int write(byte[] b,int nStart,int nLen) \ub7`01  
{ EH+"~-v)ae  
int n = -1; SA&Rep^  
try{ TaZmRL  
oSavedFile.write(b,nStart,nLen); #++lg{  
n = nLen; 6a(yp3  
} UdT*E: 6  
catch(IOException e) K -nF lPm\  
{ kj#?whK6~  
e.printStackTrace (); `x+ B+)0X  
} D=q:*x  
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return n; ^cOUQ33  
} "%`1]Fr  
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} py$Q  
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/* [<lHCQXJ/  
**SiteInfoBean.java Z;ht  
*/ $SlIr<'*"  
package NetFox; wcrCEX=I>{  
!a{^=#qq&I  
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public class SiteInfoBean { h{)kQLuzT  
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private String sSiteURL; //Site's URL lUOF4U&r  
private String sFilePath; //Saved File's Path |U:k,YH  
private String sFileName; //Saved File's Name qk%;on&`  
private int nSplitter; //Count of Splited Downloading File 1T"`vtR  
>nJ\BPx  
AHD=<7Rs  
public SiteInfoBean() QmQ=q7  
{//nSplitter的缺省值为5 Eq%}  
//default value of nSplitter is 5 /Wi[OT14  
this("","","",5); 3atBX5  
} Tr_w]'  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =mO vs  
{ fe\mL mK9  
sSiteURL= sURL; ahJ`T*)
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sFilePath = sPath; 1$xNUsD2  
sFileName = sName; ${<%" hR$  
this.nSplitter = nSpiltter; ]Z>}6!  
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mUNn%E:7@{  
} 'F/~o1\.  
MU($|hwiL  
:">!r.Q  
public String getSSiteURL() 6Pz4\uE=  
{ piJu+tUy  
return sSiteURL; RFi S@.7  
} qz"}g/;?  
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public void setSSiteURL(String value) LGq'WU31:)  
{ DEBB()6,  
sSiteURL = value; :,3C 0T3r  
} TYy?KG>:'  
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public String getSFilePath() ]tim,7s  
{ y8d]9sX{  
return sFilePath; K='z G*$l  
} S){)Z  
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public void setSFilePath(String value) e|g5=2(Pr&  
{ g1;:KzVv  
sFilePath = value; %2}-2}[>  
} a]$1D!Anc  
f- K+]aZ)  
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public String getSFileName() _jvxc'6  
{ SUMrFd~  
return sFileName; =
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} h!M  
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public void setSFileName(String value) Ozw.siD  
{ Vouvr<43o  
sFileName = value; oro$wFxJO  
} nxO"ua  
aKJwofD  
{IjF+@I  
public int getNSplitter() LHyB3V  
{ mWv3!i;G<s  
return nSplitter; 9G9t" {  
} H!@kO]?n  
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2\R'@L*  
public void setNSplitter(int nCount) !({}(!P .  
{ &U{#Kt5q  
nSplitter = nCount; vXev$x=w-  
} FX;QG94!  
} ~Q*%DRd&Z-  
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/* CYt?,qk-r  
**Utility.java M "ui0 ac  
*/ y3vdUauOn  
package NetFox; l(yZO$
  
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public class Utility { B[qzUD*P_n  
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public Utility() }?lrU.@zg  
{ V[mT<Lc  
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} YP 6`L  
6=kEyJT'  
//线程睡眠 ,yC-+VL  
public static void sleep(int nSecond) 6o^,@~:R  
{ Cwr~HY  
try{ .b_)%jd x  
Thread.sleep(nSecond);
/Jta^Bj  
} =NpYFKmMhV  
catch(Exception e) ht|z<XJ  
{ mD/9J5:  
e.printStackTrace (); ~W*FCG#E  
} AJt+p&I[J  
} +\x,HsUc"  
0mpX)S  
//日志 N%kt3vmQ_  
public static void log(String sMsg) eP.wOl  
{ t9nqu!);  
System.err.println(sMsg);  Fiv3 {.  
} ,k.3|aZE  
``V" D  
XND|h#i8  
public static void log(int sMsg) @>u}eB>Kn  
{ d^@dzNv  
System.err.println(sMsg); Ki4r<>\l{H  
} ?fiIwF)  
} 7X`l&7IXP  
}\hVy(\c  
)5rb&M}  
/* Ut*`:]la  
**TestMethod.java i=ea ?eT`  
*/ YA''2Ii  
package NetFox; O $LfuL  
63^O|y\W8  
1=r#d-\tR  
public class TestMethod { ? 8)'oMD  
:C7_Jp*Qv  
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public TestMethod() @u.58H& }R  
{ ///xx/weblogic60b2_win.exe bG7O  
try{ bhID#&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); hM@ HA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :Uz|3gq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); t,QyfN  
fileFetch.start(); ccNd'2P  
} *,3SGcYdJj  
catch(Exception e){e.printStackTrace ();} S\LkL]qx  
5BWH-2HsB  
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} .Fs7z7?Y  
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public static void main(String[] args) Vdtry@Q  
{ :imW\@u  
new TestMethod(); dUsYZdQs  
} 5}:-h>  
} h xSKG  
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