http断点续传简单实现（java)

/* bU(t5 [
  
**SiteFileFetch.java j`ggg]"&$  
*/ .6f %"E,  
package NetFox; [6)`wi  
import java.io.*; vR-rCve$P  
import java.net.*; |o
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public class SiteFileFetch extends Thread { vgo-[^FiP$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 97NF*-)N  
long[] nStartPos; //开始位置 k9'%8(7M:  
long[] nEndPos; //结束位置 N>'1<i?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \0'o*nlJ  
long nFileLength; //文件长度 #V*<G#B  
boolean bFirst = true; //是否第一次取文件 M($dh9A_  
boolean bStop = false; //停止标志 ?4(uwXp  
File tmpFile; //文件下载的临时信息 9Clddjf?c  
DataOutputStream output; //输出到文件的输出流 <eI7xifD  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） thl{IU  
public SiteFileFetch(SiteInfoBean bean) throws IOException # ]&=]K1V  
{ |:L<Ko  
siteInfoBean = bean; _:?)2NV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]aXCi"fMs  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v
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if(tmpFile.exists ()) wQlK[F]!>  
{ JrQ*.lJj  
bFirst = false; G*3O5m  
read_nPos(); ?)'j;1_=E3  
} [% KBc}  
else Uw)?u$+ P  
{ "!9~77  
nStartPos = new long[bean.getNSplitter()]; #4Xe zj,g*  
nEndPos = new long[bean.getNSplitter()]; "Z#97Jc+J  
} w}K<,5I>  
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}  9 k)?-  
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public void run() 0bzD-K4WVd  
{ 6Z\[{S];  
//获得文件长度 $._p !,<  
//分割文件 ;.'2ZNt2  
//实例FileSplitterFetch $ThkK3  
//启动FileSplitterFetch线程 LK)0g4{  
//等待子线程返回 ,H'O`oV!1E  
try{ & 2& K9R  
if(bFirst) 9<W0'6%{/  
{ i:ZpAo+Z{  
nFileLength = getFileSize(); .^X IZ  
if(nFileLength == -1) {UT^pIP\  
{ :%{MMhbx  
System.err.println("File Length is not known!"); #Kyb9Qg  
} Vdjf F&q  
else if(nFileLength == -2) /g< T
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{ JLp.bxx  
System.err.println("File is not access!");
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} IwiR2K  
else 7ZI!$J|  
{ .zAB)rNc |  
for(int i=0;i<nStartPos.length;i++) EXK~Zf|&Z  
{ 1X.5cl?V  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &D\~-fOGb  
} `[0.G0i  
for(int i=0;i<nEndPos.length-1;i++) q UY;CEf  
{ 4xjk^N9  
nEndPos = nStartPos[i+1]; =iB0ak  
} Q>cLGdzO  
nEndPos[nEndPos.length-1] = nFileLength; wwF]+w%lOw  
} Klzsr,  
} @f-0OX$*  
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//启动子线程 MW &iNioX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Q4
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for(int i=0;i<nStartPos.length;i++) J0~Ha u  
{ Qb!9QlW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C%85Aq*4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 22a$//}E  
nStartPos,nEndPos,i); O{y2tz3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~3dBt@%0  
fileSplitterFetch.start(); |
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} MS%xOB*6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q|rrbxb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); DI'wZy
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", NmthvKhH  
nEndPos = " + nFileLength); NJ9H=  
// fileSplitterFetch[nPos.length-1].start(); hub1rY|No  
Mf^ ;('~  
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//等待子线程结束 /0>Cy\eN0  
//int count = 0; MoIVval/  
//是否结束while循环 RAxAy{  
boolean breakWhile = false; oC#@9>+@+"  
9s5gi+l_O  
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while(!bStop) 8p }E  
{ i:0~%X  
write_nPos(); B9`nV.a  
Utility.sleep(500); sa36=:5x-  
breakWhile = true; w8:~LX.n  
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V lN&Lz  
for(int i=0;i<nStartPos.length;i++) ^n"ve2  
{ !n~p?joJ*  
if(!fileSplitterFetch.bDownOver) ?*zRM?*  
{ |d?0ZA:z  
breakWhile = false; {x40W0  
break; m*tmmP4R  
} hhLEU_U  
} 9]r6V   
if(breakWhile) ymT&[+V  
break; &ok2Xw  
LGGC=;{}  
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//count++; tRZCOEo4  
//if(count>4) EtK,C~C}8  
// siteStop(); UbE*x2N  
} <ppM
\$  
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System.err.println("文件下载结束！"); )=V0  
} $rD&rsx6  
catch(Exception e){e.printStackTrace ();} 7 [N1Vr(1  
} Zmw'.hL  
+FRXTku(  
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//获得文件长度 _"6{Rb53v=  
public long getFileSize() :jKDM  
{ by,"Orpwq;  
int nFileLength = -1; 23BzD^2a  
try{ f8'D{OP"G  
URL url = new URL(siteInfoBean.getSSiteURL()); hVo]fD|W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^$c+r%9k  
httpConnection.setRequestProperty("User-Agent","NetFox"); )"s <hR,  
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int responseCode=httpConnection.getResponseCode(); 7Rqjf6kX`O  
if(responseCode>=400) 3yn>9qt  
{ N1`/~Gi  
processErrorCode(responseCode); H]K(`)y}4  
return -2; //-2 represent access is error )<-\ F%&b  
} k;/U6,LQ*  
/DA'p[,  
6 6WAD$8$  
String sHeader; Ll\y2oJ  
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for(int i=1;;i++) | z=:D*uh~  
{ vzA)pB~;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `?{i dg  
//Utility.log(in.readLine()); _PZGns,u  
sHeader=httpConnection.getHeaderFieldKey(i); }a6

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if(sHeader!=null) #9uNJla
 
{ ;2y3i5^k  
if(sHeader.equals("Content-Length")) ?(UeWLC#  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m?VA 1  
break; GY%lPp  
} oMk6ZzZ,>  
} cL}}^  
else $x#0m  
break; ZE863M@.  
} T+7-6y+ d  
} 6Ty;m>j  
catch(IOException e){e.printStackTrace ();} `3m7b!0k  
catch(Exception e){e.printStackTrace ();} MlVN'w  
'F.Da#st!}  
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Utility.log(nFileLength); *f{\ze@5=  
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return nFileLength; f-&4x_5  
} Q]wM WV  
#lXwBfBMf  
:23w[vt=  
//保存下载信息（文件指针位置） ;DbEP.%u$  
private void write_nPos() xwoK#eC~F  
{ +Z99x#  
try{ da<B6!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @."_XL74  
output.writeInt(nStartPos.length); PoTJ4z  
for(int i=0;i<nStartPos.length;i++) {2QCdj46  
{ mDZ/Kp{  
// output.writeLong(nPos); o|FjNL  
output.writeLong(fileSplitterFetch.nStartPos); Hy}oSy26  
output.writeLong(fileSplitterFetch.nEndPos); 30 e>C  
} AlF"1X02  
output.close(); Q |,(C0<G  
} If[4]-dq  
catch(IOException e){e.printStackTrace ();} 8>Az<EF^=#  
catch(Exception e){e.printStackTrace ();} NbnahhS  
}  1$nlRQi  
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//读取保存的下载信息（文件指针位置） lr[U6CJY  
private void read_nPos() K@yLcgr{O2  
{ *l\wl @{  
try{ p,#t[K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ypyqf55gK  
int nCount = input.readInt(); N 0<([B;  
nStartPos = new long[nCount]; Yl}'hRp  
nEndPos = new long[nCount]; +ZOjbI)  
for(int i=0;i<nStartPos.length;i++) Uj]Tdg  
{ 5qZe
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nStartPos = input.readLong(); zl8O @g  
nEndPos = input.readLong(); n$]78\C  
} pK/r{/>r  
input.close(); oihn`DY{  
} NL`}rj  
catch(IOException e){e.printStackTrace ();} 8x":7 yV&  
catch(Exception e){e.printStackTrace ();} DXFU~J*  
} i"
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!' ;1;k);  
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private void processErrorCode(int nErrorCode) .T;:6/??1  
{ $#2zxpr,  
System.err.println("Error Code : " + nErrorCode); Jc8^m0_  
} ^!a4!DGVT  
2;&K*>g&.  
m/M=.\]  
//停止文件下载 Gs`[\<;LI  
public void siteStop() ",&^ f  
{ xLX2F  
bStop = true; Z9S5rPHEL  
for(int i=0;i<nStartPos.length;i++) 'F-;uN  
fileSplitterFetch.splitterStop(); v/ $~ifY"  
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} (^),G-]  
} .AHf]X0  
//负责部分文件的抓取 ')G,+d^  
**FileSplitterFetch.java =17d7#-  
*/ 0<ze'FbV]  
package NetFox; 04o>POR  
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import java.io.*; 3:H[S_q  
import java.net.*; Mk=
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public class FileSplitterFetch extends Thread { w^BF.Nu  
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String sURL; //File URL kh7RQbNY<I  
long nStartPos; //File Snippet Start Position ([g[\c,H  
long nEndPos; //File Snippet End Position kJP`C\4}f  
int nThreadID; //Thread's ID E}qW'  
boolean bDownOver = false; //Downing is over d1[;~)  
boolean bStop = false; //Stop identical U!y GZEU"[  
FileAccessI fileAccessI = null; //File Access interface ;,WI_iP(w  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException FqWW[Bgd  
{ Jam&Rj,  
this.sURL = sURL; }Mv$Up  
this.nStartPos = nStart; u)X]]6
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this.nEndPos = nEnd; 5u5-:#sLy  
nThreadID = id; =\ek;d0Tqb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ScCp88KpFI  
} 6y0CEly>3#  
4LY$;J;2  
;xXD2{q  
public void run() ffH]`N  
{ P* Z1Rs_  
while(nStartPos < nEndPos && !bStop) JKjVrx> @  
{ *#y9Pve  
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try{ " J4?Sb<  
URL url = new URL(sURL); d~QZcR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fK 4,k:YC  
httpConnection.setRequestProperty("User-Agent","NetFox"); [@_IUvf^.  
String sProperty = "bytes="+nStartPos+"-"; ~DL-@*&  
httpConnection.setRequestProperty("RANGE",sProperty); 7=wPd4  
Utility.log(sProperty); Jn\@wF9xd  
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InputStream input = httpConnection.getInputStream(); 7;8DKY q  
//logResponseHead(httpConnection); F!RzF7h1  
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byte[] b = new byte[1024]; QAxR'.d  
int nRead; =".sCV9"N  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Dug{)h_2  
{ AqZ()p*z  
nStartPos += fileAccessI.write(b,0,nRead); j6&q6C X  
//if(nThreadID == 1) eWk W,a  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6Zx'$F.iqK  
} :OKU@l|  
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Utility.log("Thread " + nThreadID + " is over!"); AMSn^75  
bDownOver = true; uS|f|)U&  
//nPos = fileAccessI.write (b,0,nRead); T/Bx3VWL  
} 1nZ7xCDK98  
catch(Exception e){e.printStackTrace ();} 4qKMnYR  
} ETQL,t9m  
} cT.8&EEW  
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//打印回应的头信息 @xkI?vK6  
public void logResponseHead(HttpURLConnection con)  m1#,B<6  
{
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for(int i=1;;i++) .a_xQ]eQ  
{ IKFNu9*"h  
String header=con.getHeaderFieldKey(i); KB`">zq$u  
if(header!=null) 8(@Y@`/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); '-2|GX_o  
Utility.log(header+" : "+con.getHeaderField(header)); Cj10?BNV)  
else 8h{;*Wr-  
break; 1\LK[tvh  
} @tfatq+q  
} i}_d&.DbF  
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$.Qu55=z<  
public void splitterStop() ~E3"
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{ m^%Xl@V:c-  
bStop = true; @~j--L  
} OlcWptM$  
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} ApotRr$)  
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/* Q39;bz
  
**FileAccess.java w<me(!-'  
*//文件访问(定位，写) Lv<)Dur0K  
package NetFox; HI!bq%TZ4  
import java.io.*; dx)v`.%V  
3F\UEpQ  
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public class FileAccessI implements Serializable{ tKLAA+Z  
be(p13&od  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |>Wi5h{6X  
RandomAccessFile oSavedFile; Y6ORI  
long nPos; gVpp9VB  
+l@+e_>  
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public FileAccessI() throws IOException mF@DO$  
{ 9 :FzSD   
this("",0); uTIl} N  
} tg%C>O  
nTH!_S>b(Y  
tRzo}_+N
 
public FileAccessI(String sName,long nPos) throws IOException #e5*Dr8  
{ H
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oSavedFile = new RandomAccessFile(sName,"rw"); F^}n7h=qk  
this.nPos = nPos; $-R9J6NN  
oSavedFile.seek(nPos); z! DD'8r>  
}  j.vBld  
w*qmC<D$A  
I3D#wXW  
public synchronized int write(byte[] b,int nStart,int nLen) QP[
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{ DOGg=`XK1  
int n = -1; ]qNPOnlp  
try{ F
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oSavedFile.write(b,nStart,nLen); % ovk}}%;  
n = nLen; QAK.Qk?Qu  
} RWK##VHK  
catch(IOException e)
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{ :rX/ILAr  
e.printStackTrace (); n$YCIW)0  
} 'P,F)*kh  
WgC*bp{  
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return n; $C?G7Vs  
} Q=cbHDB  
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} Mb[4G>-v=  
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/* $[-{Mm  
**SiteInfoBean.java C
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*/ ^_^rI+cTX1  
package NetFox; "yV)&4)  
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?FRQ!R  
public class SiteInfoBean { fl18x;^I  
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private String sSiteURL; //Site's URL !WReThq  
private String sFilePath; //Saved File's Path ^Wz3 q-^  
private String sFileName; //Saved File's Name [j`-R 0Np  
private int nSplitter; //Count of Splited Downloading File Cb/?hT  
@5-+>\Hd^t  
*tZ#^YG{(  
public SiteInfoBean() vaEAjg*To<  
{//nSplitter的缺省值为5 .+cYzS]!  
//default value of nSplitter is 5 sw@*N  
this("","","",5); S.Fip_  
} ]0wmvTR  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MB,P#7|  
{ f3]u-e'b  
sSiteURL= sURL; H9Pe,eHs  
sFilePath = sPath; 1yIo'i1  
sFileName = sName; .DkDMg1US  
this.nSplitter = nSpiltter; L5*,l`lET  
8E!I9z  
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} ,`JXBI~  
^D0BGC&&  
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public String getSSiteURL() ;ckv$S[p  
{ d#eHX|+  
return sSiteURL; m'%Z53&  
} r6-'p0|   
OWK)4[HY(  
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public void setSSiteURL(String value) ?JD\pYg[/  
{ !u#o"e<qh  
sSiteURL = value; It\ob7n  
} fV.43E  
db!2nImNu\  
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public String getSFilePath() aUy=D:\  
{ OQh36BM  
return sFilePath; r4xq%hy  
} B&m?3w  
O:a$ U:  
wzMWuA4vX  
public void setSFilePath(String value) Ye}y
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{ n~d`PGs?f  
sFilePath = value; }m<)$.x|P  
} dMwVgc:  
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public String getSFileName() A{E0 
a:v  
{ Y4Z?`TL  
return sFileName; t747SZWgB  
} vN7ihe[C  
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o+
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public void setSFileName(String value) 8[FC  
{ *3
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sFileName = value; FJ}QKDQW=  
} G<-)Kx  
K(plzQ3  
f41!+W=  
public int getNSplitter() 00G[`a5  
{ cQv*lvG9>  
return nSplitter; `4&\ %9  
} <!zItFMD[m  
5hpb=2  
\Rp)n=|  
public void setNSplitter(int nCount) DrltxI)  
{ C_#0Y_O  
nSplitter = nCount; F ,{nG[PL  
} 3@}HdLmN|  
} %'* |N[  
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/* 7Hpsmfm  
**Utility.java ){>;eky  
*/ ~pj9_I  
package NetFox; #IBBaxOk  
X5U!25d]  
[-$&pB>w8'  
public class Utility { }M
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public Utility() {djOU 9]  
{ oT|E\wj  
u(ZS sftat  
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} BJj~fNm1Zr  
3 XfXMVm  
//线程睡眠 SsznV}{^  
public static void sleep(int nSecond) mk4%]t"  
{ jd2Fh):q  
try{ m2|0<P@k!  
Thread.sleep(nSecond); !gf&l ^)  
} 'KQuz)-  
catch(Exception e) 5Cy)#Z{  
{ VY _(0  
e.printStackTrace (); hkU# lt  
} Ky nZzR  
} wOi>i`D&  
5[gkGKkf_  
//日志 ?o.G@-  
public static void log(String sMsg) =,@SZsM*B  
{ *qb`wg  
System.err.println(sMsg); Op%^dwVG(v  
} u khI#:[  
1C$^S]v%a  
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public static void log(int sMsg) K.z}%a  
{ e('c9 Y  
System.err.println(sMsg); "4tRy9q  
} *h =7:*n  
} x(b&r g.-0  
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ao-C9|2>NU  
/* 2%8N<GW.F  
**TestMethod.java *Nt6 Ufq6  
*/ 4UL-j  
package NetFox; I$mOy{/#  
n)K6Z{x  
AN~1E@"  
public class TestMethod { `z=MI66Nl  
a|7V{pp=M  
+u=xBhZ  
public TestMethod() K5.C*|w  
{ ///xx/weblogic60b2_win.exe iuHG9#n  
try{ ;%jt;Xv9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /BIPLDN6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); If&p$pAH?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @W @L%<  
fileFetch.start(); 5;^8wh(  
} 9M7P]$^  
catch(Exception e){e.printStackTrace ();} ev?>Nq+Z  
d;;=s=j  
)nJ>kbO~8  
} @P.l8|w  
2d>PN^x  
ifgaBXT55  
public static void main(String[] args) ~b7Nzzfo  
{ s=q+3NTv  
new TestMethod(); -xcz+pHQ  
} 1OGlD+f  
} NfO0^^"  
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