http断点续传简单实现（java)

/* ch5s<x#CE  
**SiteFileFetch.java *zO&N^X.4  
*/ ck#"*],  
package NetFox; L]a`"CH:a$  
import java.io.*; TEUY3z[g  
import java.net.*; KlK`;cr?  
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public class SiteFileFetch extends Thread { TG n-7 88  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -ZW0k@5g  
long[] nStartPos; //开始位置 9Pd*z>s  
long[] nEndPos; //结束位置 0;
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 s?WCnT  
long nFileLength; //文件长度 ()PKw,pD  
boolean bFirst = true; //是否第一次取文件 F2(q>#<_  
boolean bStop = false; //停止标志 v;{{ y-  
File tmpFile; //文件下载的临时信息 Uadr>#C*  
DataOutputStream output; //输出到文件的输出流 5CAR{|a  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） NV4g~+n  
public SiteFileFetch(SiteInfoBean bean) throws IOException PIcrA2ll  
{ 4([.xT  
siteInfoBean = bean; HEK-L)S. *  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l? #xAZx&_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); a)*6gf<5  
if(tmpFile.exists ()) 3*DXE9gA9  
{ ^GN8V-X4y  
bFirst = false; QbYc[8-[  
read_nPos(); /Tz85 [%6  
} x4Rk<Th"o  
else '%v#v3'  
{ Z.Rb~n&  
nStartPos = new long[bean.getNSplitter()]; c*\<,n_  
nEndPos = new long[bean.getNSplitter()]; b7C e%Br  
} U7&x rif  
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} ;D ~L|  
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public void run() D-9\~gvh  
{ G,&%VQ3P>  
//获得文件长度 iNcZ)m/  
//分割文件 5IVks
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//实例FileSplitterFetch :lcea6iO  
//启动FileSplitterFetch线程 9T2xU3UyY  
//等待子线程返回 /I&wj^  
try{ _17|U K|N  
if(bFirst) uK*Nu^  
{ Z+s%;f;  
nFileLength = getFileSize(); @-.? B  
if(nFileLength == -1) Z\X'd_1!  
{ qZ2&Xw.{1  
System.err.println("File Length is not known!"); Bt^K]F\  
} ~>ME'D~  
else if(nFileLength == -2) %@&a7JOL  
{ OQ_stE2i  
System.err.println("File is not access!"); +2cs
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} c yQ(fIYl  
else +R$?2  
{ O^{1RV3:,T  
for(int i=0;i<nStartPos.length;i++) "i'bTVs  
{ DrS~lTf=>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?s} %  
} t> Q{yw  
for(int i=0;i<nEndPos.length-1;i++) x49!{}  
{ J$uM 03  
nEndPos = nStartPos[i+1]; ~HLRfL?  
} _rQUE
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nEndPos[nEndPos.length-1] = nFileLength; #,f{Ok+  
} XL< )v_  
} H;_yRUY9  
-@%%*YI>  
@ "d2.h  
//启动子线程 `
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -$Y8!54  
for(int i=0;i<nStartPos.length;i++) ^,s?e.u$8`  
{ fhpX/WE6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V: p)m&y6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gqiXmMm:9  
nStartPos,nEndPos,i); _pDjg%A>n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =(U/CI  
fileSplitterFetch.start(); K\=8eg93Z  
} -R+zeu(e'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;'kI/(;;C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T@+ClZi  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OS7RQw1  
nEndPos = " + nFileLength); 10N,?a  
// fileSplitterFetch[nPos.length-1].start(); B< ;==|  
c cG['7  
Jgx8-\8  
//等待子线程结束 w[fDk1H)  
//int count = 0; :uCdq`SaQl  
//是否结束while循环 ?A=b6Um  
boolean breakWhile = false; 4^Qi2[w  
Z}Cqd?_')  
TnxKR$Hoh  
while(!bStop) 5rN_jC*U  
{ 2RNrIU I2  
write_nPos(); Ghv{'5w  
Utility.sleep(500); _\
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breakWhile = true; nsJ:Osq|  
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for(int i=0;i<nStartPos.length;i++) eqzTQen8q  
{ `q?RF+  
if(!fileSplitterFetch.bDownOver) \XH@b6{  
{ VyZV(k  
breakWhile = false; +t\^(SJ6  
break; XI}I.M  
} mY2:m(9"5  
} b :\D\X  
if(breakWhile) P.4E{.)(  
break; g^lFML| %  
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w!,QxrOV~  
//count++; D$pj#  
//if(count>4) wa?+qiWnrl  
// siteStop(); ZJXqCo7O  
} nk08>veG  
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System.err.println("文件下载结束！"); 3"i%{  
} qpgU8f  
catch(Exception e){e.printStackTrace ();} 70`M,``  
} sco uO$
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//获得文件长度 m#ad6 \  
public long getFileSize() A~y VYC6l  
{ R7K  
int nFileLength = -1; wXCyj+XB*  
try{ {visv{R<  
URL url = new URL(siteInfoBean.getSSiteURL()); }u
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I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ru7L>(Njs  
httpConnection.setRequestProperty("User-Agent","NetFox"); Yf(im  
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F ?mA1T>x  
int responseCode=httpConnection.getResponseCode(); 9/46%=&]
 
if(responseCode>=400) d=nh  
{ `QLowna  
processErrorCode(responseCode); '5WN,Vy8.  
return -2; //-2 represent access is error i+U51t<  
} !$E~\uT  
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7 6*hc   
String sHeader; m+$/DD^-zl  
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for(int i=1;;i++) ,?w!5N;iRO  
{ ![H
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7K !GK  
//Utility.log(in.readLine()); lm &^tjx  
sHeader=httpConnection.getHeaderFieldKey(i); +3?`M<L0  
if(sHeader!=null) R#fy60  
{ ;y>'yq}  
if(sHeader.equals("Content-Length")) Jk~UEqr+  
{ >Jiij  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jaa/k@OG  
break; yy))Z0E5  
} =#'+"+lQ }  
} GU#Q}L2  
else >0M:&NMda  
break; `vH&K{  
} h9Z[z73_a  
} 8!6<p[_  
catch(IOException e){e.printStackTrace ();} okh0_4  
catch(Exception e){e.printStackTrace ();} I$Eg$q  
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Utility.log(nFileLength); Ctj8tK
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return nFileLength; [wIKK/O  
} -g$OOJB6  
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//保存下载信息（文件指针位置） yHtGp%j  
private void write_nPos() 8tC+ lc  
{ 5D-BIPn=JV  
try{ clC~2:  
output = new DataOutputStream(new FileOutputStream(tmpFile));  3:"AFV  
output.writeInt(nStartPos.length); kFnUJM$r  
for(int i=0;i<nStartPos.length;i++) (Z'WR  
{ 3liq9P_  
// output.writeLong(nPos); a(g$ d2H  
output.writeLong(fileSplitterFetch.nStartPos); |'@V<^GR  
output.writeLong(fileSplitterFetch.nEndPos); K.r!?cfv  
} mR6E]TuM  
output.close(); P69>gBZYD  
} b/G8Mr  
catch(IOException e){e.printStackTrace ();} D~7%};D[  
catch(Exception e){e.printStackTrace ();} y#nSk%"t"  
} w0\4Wa  
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ju r1!rg%  
//读取保存的下载信息（文件指针位置） q>c+bo 6  
private void read_nPos() h#;?9DP  
{ [I_BCf  
try{ a\Tr!Be,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bL#sn_(m  
int nCount = input.readInt(); J;7s/YH^  
nStartPos = new long[nCount]; m_~y  
nEndPos = new long[nCount]; 9PWm@ Nlf  
for(int i=0;i<nStartPos.length;i++) u`nt\OF  
{ '|J)ds  
nStartPos = input.readLong(); ,%.:g65%  
nEndPos = input.readLong(); d7\k gh  
} ;q'DGzh  
input.close(); y K=S!7p\  
} |\rSa^:5  
catch(IOException e){e.printStackTrace ();} /;[
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catch(Exception e){e.printStackTrace ();} }q/(D?  
} pEJ#ad  
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private void processErrorCode(int nErrorCode) }i
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{ 8x`Kl(  
System.err.println("Error Code : " + nErrorCode); ,d3Q+9/  
} \;'_|bu3.  
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//停止文件下载 .59KE]u  
public void siteStop() K%kXS  
{ aViJ   
bStop = true; 4|I7:~  
for(int i=0;i<nStartPos.length;i++) |qQ{8T%)  
fileSplitterFetch.splitterStop(); ;,()wH  
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A  
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} ll 6]W~[ZC  
} EaJDz`T}  
//负责部分文件的抓取 ~r{\WZ.  
**FileSplitterFetch.java 4o)(d=q  
*/ C+ZQB)gn  
package NetFox; 'nC3:U  
A!Knp=Gw  
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import java.io.*; >SY2LmV'a  
import java.net.*; hwEZj`9  
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public class FileSplitterFetch extends Thread { 5B8V$ X  
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String sURL; //File URL {d&X/tT  
long nStartPos; //File Snippet Start Position CM+F7#T?n  
long nEndPos; //File Snippet End Position nNd`]F^U  
int nThreadID; //Thread's ID Q$/V)0  
boolean bDownOver = false; //Downing is over +9Xu"OFm  
boolean bStop = false; //Stop identical s
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FileAccessI fileAccessI = null; //File Access interface OHx,*
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}wa}hIqx  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException } IIK~d,  
{ |iLx$P6  
this.sURL = sURL;  muK'h`  
this.nStartPos = nStart; rTWh(8T  
this.nEndPos = nEnd; YlZYS'_  
nThreadID = id; 7F>gj  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >!:$@!6L  
} 2GHXn:V  
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public void run() >C*?17\  
{
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while(nStartPos < nEndPos && !bStop) )x_W&*oZ  
{ HP
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try{ Zj%B7s1A  
URL url = new URL(sURL); l044c,AW(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  ?.4y
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httpConnection.setRequestProperty("User-Agent","NetFox"); Fi,e}j=2f  
String sProperty = "bytes="+nStartPos+"-"; XhHel|!g:  
httpConnection.setRequestProperty("RANGE",sProperty); v#F
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Utility.log(sProperty); {ar5c&<  
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InputStream input = httpConnection.getInputStream(); 1]D/3!  
//logResponseHead(httpConnection); j]@x Q,y  
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byte[] b = new byte[1024]; CS^ oiV%{s  
int nRead; 1B9
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [[/ }1%  
{ Mhu53DT  
nStartPos += fileAccessI.write(b,0,nRead); uMiD*6,$<  
//if(nThreadID == 1) !0!P.Q8>&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i/C -{+}U  
} _G-bL;  
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Utility.log("Thread " + nThreadID + " is over!"); ZTgAZ5_cz  
bDownOver = true; ;*<{*6;=?  
//nPos = fileAccessI.write (b,0,nRead); Nf/hr%jL  
} %~~z96(  
catch(Exception e){e.printStackTrace ();} n6}E4E
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} l1+w2r
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} Q%X:5G
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//打印回应的头信息 |2t7G9[n  
public void logResponseHead(HttpURLConnection con) VrAXOUJw6  
{ 0,"n-5Im  
for(int i=1;;i++) u@:=qd=\  
{ {LMS~nx  
String header=con.getHeaderFieldKey(i); gr[ "A  
if(header!=null) "FLD%3l  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $,z[XM&9)  
Utility.log(header+" : "+con.getHeaderField(header)); LoV*YS
DAY  
else ,\m;DR1  
break; #um1?V  
} /q*Qx )y+1  
} m&8U4uHN  
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public void splitterStop() O_s9  
{ b Q9"GO<X  
bStop = true; Us@ {w`T  
} [X$|dOm'N  
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} vBCZ/F[  
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/* :(S/$^U  
**FileAccess.java RB$ 8^#  
*//文件访问(定位，写) L[QI 5N  
package NetFox; "PDSqYA  
import java.io.*; +n8I(l=  
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public class FileAccessI implements Serializable{ gqHH Hh  
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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 go%X%Os]  
RandomAccessFile oSavedFile; nkCRe  
long nPos; q=E}#[EgY  
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public FileAccessI() throws IOException 5Ky9Pz  
{ e G*s1
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this("",0); EDa08+Y  
} U7f&N  
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public FileAccessI(String sName,long nPos) throws IOException Vp{RX8?.  
{ {7M4SC@p|  
oSavedFile = new RandomAccessFile(sName,"rw"); )*$  
this.nPos = nPos; ~A:;?A'.  
oSavedFile.seek(nPos); b$`4Nn|  
} ]B[/sqf  
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public synchronized int write(byte[] b,int nStart,int nLen) E{k%d39>  
{ L[[H&#\  
int n = -1; )l!&i?h%  
try{ IpaJ<~ p  
oSavedFile.write(b,nStart,nLen); !i"9f_  
n = nLen; dC;d>j,  
} >`,#%MH#  
catch(IOException e) EK-bvZ  
{ t&Y^W <  
e.printStackTrace (); 6
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} x+)hL D[ n  
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return n; 0wE8GmG  
} FUTyx"   
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} *}WqYqOow  
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/* |sZ9/G7  
**SiteInfoBean.java O9 Au =  
*/ ewff(e9  
package NetFox; QX~72X=(  
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public class SiteInfoBean { o _,$`nEJ  
zm^p7&ak$  
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private String sSiteURL; //Site's URL ~(doy@0M  
private String sFilePath; //Saved File's Path @Oc}\Rg  
private String sFileName; //Saved File's Name _q!ck0_  
private int nSplitter; //Count of Splited Downloading File h^,YYoA$  
[`nyq)  
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public SiteInfoBean() K]azUK7  
{//nSplitter的缺省值为5 GISI8W^  
//default value of nSplitter is 5 g8
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this("","","",5); xx2:5  
} %;XuA*e  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I Y-5/
 
{ X/D9%[{&  
sSiteURL= sURL; gGz_t,=  
sFilePath = sPath; MhB=+S[@  
sFileName = sName; j:<T<8.o  
this.nSplitter = nSpiltter; 5UD;ZV%  
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} :z5Ibas:  
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public String getSSiteURL() o~N-
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{ !Dn1pjxc  
return sSiteURL; :<G+)hIK  
} *wl_8Sis}  
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public void setSSiteURL(String value) Zl/+HU~  
{ UE](`|4H  
sSiteURL = value; ag4^y&  
} 3]82gZGG  
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public String getSFilePath() u"3cSuqy  
{ oO,p.X%  
return sFilePath; *\5H\s9<  
} 438>)=  
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public void setSFilePath(String value) ;L{y3CWT  
{ $9b6,Y
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sFilePath = value; Yhdt8[ 2  
} $O>MV  

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public String getSFileName() V3nv5/6  
{ g9`ytWmM  
return sFileName; #_5+kBA+>'  
} !kYmrj**  
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public void setSFileName(String value) ,*#M%Pv1t  
{ iTyApLV  
sFileName = value; p#I1l2nE  
} 4iPg_+  
Lf<9GYNy>`  
G]4+Qr?  
public int getNSplitter() 'S ;vv]}Gs  
{ }gt~{9?c  
return nSplitter; W12K93tO  
} nhxl#  
#.aLx$"a  
+d15a%^`  
public void setNSplitter(int nCount) ;W"[,#2TM  
{ )HHzvGsL)  
nSplitter = nCount; Tj#XsD?J  
} /267Q;d C)  
} ]].21  
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r3)t5P*_  
/* %dQX d]  
**Utility.java p*,mwKN:  
*/ zAIC5fvu  
package NetFox; M?`06jQD.  
n40Z  
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public class Utility { w9BH>56/"  
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public Utility() )}8%Gs4C  
{ r~t7Z+PXF  
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} bf+2c6_BN0  
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//线程睡眠 e%\KI\u  
public static void sleep(int nSecond) AJ}Q,E  
{ w5Z3e^g  
try{ gsH_pG-jU  
Thread.sleep(nSecond); SfR_#"Uu  
} }#M|3h;q9+  
catch(Exception e) TjdYCk]'  
{ fE iEy%o  
e.printStackTrace (); xg&vZzcl  
} P{ o/F  
} +aap/sYp  
5kz`_\&  
//日志 4RNzh``u  
public static void log(String sMsg) }"v"^5  
{ >XN&QVE  
System.err.println(sMsg); j3U8@tuG  
} x$*OglaS  
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sj~'.Zs
%  
public static void log(int sMsg) 1+Oo Qs  
{ r+2dBp3  
System.err.println(sMsg); }ls>~uN  
} Qpc>5p![3  
} D]REZuHOI  
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Y`v&YcX;  
/* %!RQ:?=  
**TestMethod.java lDzVc`c  
*/ d!cx%[  
package NetFox; li?Gb1  
W=/B[@3'  
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public class TestMethod { lK0coj1+  
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public TestMethod() "#%T*c{Tf0  
{ ///xx/weblogic60b2_win.exe |O
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try{ }N NyUwFa  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); tQ"PCm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Sk xaSJ"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #+$z`C`  
fileFetch.start(); W-MQMHQ  
} !Iqyt. .  
catch(Exception e){e.printStackTrace ();} rQF%;  
:HC{6W`$  
q :gH`5N  
} >*&[bW'}?  
'"6VfF)*  
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public static void main(String[] args) c8'?Dd  
{ ;XjKWM;  
new TestMethod(); TSeAC[%pL  
} e>/PW&Z8Z  
} wp$=lU{B  
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