http断点续传简单实现（java)

/* #W L>ha v  
**SiteFileFetch.java  ixF  
*/ |e&hm ~R1  
package NetFox; Hn?v/3  
import java.io.*; Hg[AulNna  
import java.net.*; ~</H>Jd  
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public class SiteFileFetch extends Thread { w 1O)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean m8v=pab e  
long[] nStartPos; //开始位置 :\#/T,K"  
long[] nEndPos; //结束位置 )-LSn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ZV:0:k.x  
long nFileLength; //文件长度 g\?7M1~  
boolean bFirst = true; //是否第一次取文件 pH.&OW%  
boolean bStop = false; //停止标志 I}/-zyx>=  
File tmpFile; //文件下载的临时信息 Zu^J X/um  
DataOutputStream output; //输出到文件的输出流 EMS$?"K  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kc"SUiy/  
public SiteFileFetch(SiteInfoBean bean) throws IOException _ 3jY,*  
{ onUF@3V  
siteInfoBean = bean; tp+H]H3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [V,f@}m F  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x):h|/B  
if(tmpFile.exists ()) |H-zm&h>'  
{ .\AbE*lZ#  
bFirst = false; &qeMYYY  
read_nPos(); =q*j". <  
} v6KF0mqA&  
else *5S~@  
{ #mcGT\tQ  
nStartPos = new long[bean.getNSplitter()]; q6N6QI8/  
nEndPos = new long[bean.getNSplitter()]; 0$q)uip  
} Yg3emn|a  
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} 8>V)SAI'  
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public void run() @EB2I+[  
{ |1"n\4$  
//获得文件长度 h-RL`X  
//分割文件 +# tmsv]2  
//实例FileSplitterFetch VH$hQPP5d  
//启动FileSplitterFetch线程 ]s:%joj%^  
//等待子线程返回 7-MkfWH2b6  
try{ AU^5N3%j  
if(bFirst) dy2<b+
..  
{ SH M@H93  
nFileLength = getFileSize(); $r=tOD4;  
if(nFileLength == -1) 6 VuMx7W1  
{ 
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System.err.println("File Length is not known!"); ;_=+h,n  
} *z\L  
else if(nFileLength == -2) c7(Lk"G8  
{ YST{ h{  
System.err.println("File is not access!"); yixAG^<  
} $2gZpO|  
else nJ~5ICyd  
{ 97L#3L6t  
for(int i=0;i<nStartPos.length;i++) ygfUy  
{ iwT PJGK|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;R{ffS6  
} a/H|/CB3  
for(int i=0;i<nEndPos.length-1;i++) 5j$a3nH  
{ $y+Bril5W  
nEndPos = nStartPos[i+1]; o@tc  
} <;nhb  
nEndPos[nEndPos.length-1] = nFileLength; ]Br6!U4~  
} g\lEdxm6Sj  
} ;B!u=_'  
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//启动子线程 ww$Ec  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^5BQ=  
for(int i=0;i<nStartPos.length;i++) \J,pV  
{ h1.<\GO  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #=\nuT'oy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /#I~iYPe  
nStartPos,nEndPos,i); HH9
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 80;^]l   
fileSplitterFetch.start(); lcYjwA  
} C;NG#4;'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -7:_Dy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (S1Co&SX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1=Nh<FuQ  
nEndPos = " + nFileLength); ct![eWsuB  
// fileSplitterFetch[nPos.length-1].start(); 2VyJ  
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//等待子线程结束 :92
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//int count = 0; rGb<7b%  
//是否结束while循环 tDIQ=  
boolean breakWhile = false; %#$K P  
}MXC0Z~si  
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while(!bStop) @j|=M7B  
{ j0+l-]F-  
write_nPos(); E|v9khN(].  
Utility.sleep(500); Kk9W=
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breakWhile = true; p?XVO#  
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for(int i=0;i<nStartPos.length;i++) .DG`~Fpk  
{ UY$Lqe~  
if(!fileSplitterFetch.bDownOver) 7@uhw">mX  
{ @Xg5E  
breakWhile = false; *$yU|,  
break; 's_[#a;Vp  
} qaZQ1<e  
} p]erk  
if(breakWhile) $Cx?%X^b  
break; GjH$!P=.  
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//count++; \qj(`0HG  
//if(count>4) SM8Wg>  
// siteStop(); 0S71&I$u]  
} c$#7Kp4  
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System.err.println("文件下载结束！"); 3P2x%Gp  
} C 5 xsh  
catch(Exception e){e.printStackTrace ();} Q.Xs%{B  
} LZH~VkK@m}  
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//获得文件长度 BH\
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public long getFileSize() _-5|"oJ  
{ f1,VbuS9I  
int nFileLength = -1; BOdd~f%&tn  
try{ ^2)<H7p  
URL url = new URL(siteInfoBean.getSSiteURL()); &f($= 68  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9mRP%c#(  
httpConnection.setRequestProperty("User-Agent","NetFox"); c%@< h6  
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int responseCode=httpConnection.getResponseCode(); $@^*lUw  
if(responseCode>=400) 5VZZk%oy  
{ s@D/.X  
processErrorCode(responseCode); &5d~ODO  
return -2; //-2 represent access is error ;(r,;S_`0  
} 6%L#FSI  
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String sHeader; B|SE |  
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for(int i=1;;i++) b>]k=zd  
{ '@dk3:3t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~1:_wni  
//Utility.log(in.readLine()); ^2C \--=;  
sHeader=httpConnection.getHeaderFieldKey(i); 7.FD16  
if(sHeader!=null) Tnoy#w}Ve  
{ H[2W(q6  
if(sHeader.equals("Content-Length")) %Hu?syo  
{ H;{IOBo  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); GUn$IPOM  
break; d}Xb8SaE%c  
} pc2;2^U_  
} Dgc}
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else q1pB~eg5  
break; \c4D|
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} 7_ s7);  
} !xvAy3  
catch(IOException e){e.printStackTrace ();} W$xW9u8@+(  
catch(Exception e){e.printStackTrace ();} *aW:Z6
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Utility.log(nFileLength); Ubm]V{7  
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return nFileLength; ]FEDAGu
 
} suHi
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//保存下载信息（文件指针位置） RA1K$D ?A  
private void write_nPos() nxMZd=Y  
{ QjOY1Xze  
try{ . ZP$,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); lk.Mc6)  
output.writeInt(nStartPos.length); N qS]dH61  
for(int i=0;i<nStartPos.length;i++) r;_*.|AH  
{ TeRH@oI  
// output.writeLong(nPos); _$_,r H
 
output.writeLong(fileSplitterFetch.nStartPos); aGNbCm  
output.writeLong(fileSplitterFetch.nEndPos); *$Y_ %}  
} xX.kKEo"d  
output.close(); '*D>/hn|:]  
} .iYp9?t  
catch(IOException e){e.printStackTrace ();} W.BX6  
catch(Exception e){e.printStackTrace ();} _B0C]u3D  
} K-[;w$np0  
|7QSr!{_  
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//读取保存的下载信息（文件指针位置） 0BQ{ZT-Kh  
private void read_nPos() B`)TRt+'.  
{ \aN7[>R.Q  
try{ @MP;/o+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); q$PO.#  
int nCount = input.readInt(); {F;"m&3Lt  
nStartPos = new long[nCount]; {r%T_BfY  
nEndPos = new long[nCount]; n0Qp:_2z  
for(int i=0;i<nStartPos.length;i++) &v#pS!UOj  
{ XT?wCb41R  
nStartPos = input.readLong(); Clb7=@f  
nEndPos = input.readLong(); Nq1YFI>W  
} ,P%i%YPj  
input.close(); KM?w{ ~9  
} -S#jOr  
catch(IOException e){e.printStackTrace ();} 3_8W5J3I  
catch(Exception e){e.printStackTrace ();} 6)c-s|#  
} re4A5Ev$  

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private void processErrorCode(int nErrorCode) "U/yq
 
{ Nw{Cu+AwG  
System.err.println("Error Code : " + nErrorCode); jq%}=-%KE  
} tz5\O}  
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//停止文件下载 <}T7;knO  
public void siteStop() Yv.7-DHNl  
{ Xl:.`{5L  
bStop = true; A76HM@Q  
for(int i=0;i<nStartPos.length;i++) %aV~RB#  
fileSplitterFetch.splitterStop(); ^1yD&i'q  
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} nok-![  
} "'C5B>qO  
//负责部分文件的抓取 =;(L$:l~  
**FileSplitterFetch.java ~E/=
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*/ -@ra~li,yQ  
package NetFox; ^7a@?|,q8  
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import java.io.*; |*^}e54  
import java.net.*; N>CNgUyP  
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public class FileSplitterFetch extends Thread { X]o"4#CQIX  
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String sURL; //File URL 6Yc(|>b!  
long nStartPos; //File Snippet Start Position X`J86G)  
long nEndPos; //File Snippet End Position B*t1Y<>x  
int nThreadID; //Thread's ID mZG n:f}=  
boolean bDownOver = false; //Downing is over G1\F7A  
boolean bStop = false; //Stop identical vCXmu_S4^>  
FileAccessI fileAccessI = null; //File Access interface V(8,94vm  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0 vYG#S  
{ \C
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this.sURL = sURL; Zl{9G?abCT  
this.nStartPos = nStart; `sDLxgwI  
this.nEndPos = nEnd; 2j#Dwa(lZQ  
nThreadID = id; U#&+n-npO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4oL
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} OL%}C*Zq  
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public void run() *
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{ ns*:mGh  
while(nStartPos < nEndPos && !bStop) #SG.`J<%  
{ dS\!tdHP-Q  
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try{ -+M360  
URL url = new URL(sURL); o)>iHzR</  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i"xV=.  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,FXc_BCx4  
String sProperty = "bytes="+nStartPos+"-"; |f/Uzd ~  
httpConnection.setRequestProperty("RANGE",sProperty); )8oN$20  
Utility.log(sProperty); t{QQ;'  
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InputStream input = httpConnection.getInputStream(); ;xiwyfqgE  
//logResponseHead(httpConnection); ;9~ WB X"  
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byte[] b = new byte[1024]; &]GR
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int nRead; lHDZfwJ&C1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) K&zW+Cb  
{ ^b|I^TN0  
nStartPos += fileAccessI.write(b,0,nRead); =<7z :]  
//if(nThreadID == 1) |a a\t  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K&RIF]0#G  
} JWYe~  
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Utility.log("Thread " + nThreadID + " is over!"); \I-e{'h  
bDownOver = true; #p7gg61  
//nPos = fileAccessI.write (b,0,nRead); QqRF?%7q"q  
} cTS.yN({G  
catch(Exception e){e.printStackTrace ();} \#WWJh"W  
} : p)R,('g  
} ij!
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//打印回应的头信息 -FI)o`AE  
public void logResponseHead(HttpURLConnection con) lC`w}0p  
{ 4<Nd5T  
for(int i=1;;i++) :WX OD  
{ u|T]Ne  
String header=con.getHeaderFieldKey(i); *v]s&$WyO  
if(header!=null) %P M#gnt@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 97$Q?a8S@  
Utility.log(header+" : "+con.getHeaderField(header)); KO%$  
else W$2\GPJt  
break; 2K{'F1"RM  
} _x1W\#  
} /CMgWGI  
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public void splitterStop() dP+wcl4  
{ U#]J5'i  
bStop = true; ,|3_
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} de)4)EzUP  
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} JN4gH4ez)  
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/* 'S9o!hb'@  
**FileAccess.java f6yj\qq]  
*//文件访问(定位，写) cm_5,wB(w  
package NetFox; &P>& T  
import java.io.*; !02y'JS1  
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public class FileAccessI implements Serializable{ @eeI4Jz  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 od5nRb  
RandomAccessFile oSavedFile; J(@" 7RX  
long nPos; 8Iu6r}k?~`  
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{?Y\T  
public FileAccessI() throws IOException r5ldK?=k+*  
{ [DDe}D3C  
this("",0); /RMtCa~  
} 4v |i\V>M  
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public FileAccessI(String sName,long nPos) throws IOException ib#rT{e  
{ }e/vKWfT  
oSavedFile = new RandomAccessFile(sName,"rw"); `4snTM!v&  
this.nPos = nPos; IN<nZ?D#  
oSavedFile.seek(nPos); Xwdcy J!  
} yj#FO'UY  
ZS4dW_*[  
)B"{B1
(  
public synchronized int write(byte[] b,int nStart,int nLen) *$|f9jVh  
{ ^|p D(v  
int n = -1; LH)1IGAx2y  
try{ J`)/\9'&&  
oSavedFile.write(b,nStart,nLen); +6$+]u]  
n = nLen; =}Zl E  
} $[?N^   
catch(IOException e) /<n7iIK)  
{ [?|yQ x  
e.printStackTrace (); E:B"!Y6  
} vs[!B-  
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return n; 0)g]pG8&ro  
} JDZuT#  
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} 0m]QQGvJ{  
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T9&{s-3*  
/* }T(=tfv@  
**SiteInfoBean.java ~!~i_L\V  
*/ Z!~_#_Ugl  
package NetFox; z9 Ch %A{  
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public class SiteInfoBean { ?%$O7_ThvA  
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private String sSiteURL; //Site's URL 3IQI={:k|D  
private String sFilePath; //Saved File's Path +D
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private String sFileName; //Saved File's Name fX 1%I  
private int nSplitter; //Count of Splited Downloading File KYw7Jx`l  
4-SU\_  
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public SiteInfoBean() &z40l['4bz  
{//nSplitter的缺省值为5 4gC(zJ  
//default value of nSplitter is 5 @O'NJh{D`  
this("","","",5); }Vob)r{R@  
} HVoPJ!K3  
4)D~S4{E5  
 K];]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F"k`PF*b  
{  B>:U  
sSiteURL= sURL; i6k6l%  
sFilePath = sPath; 2^ ]^Yc  
sFileName = sName; CN ( :  
this.nSplitter = nSpiltter; l$\B>u,>  
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} J/K~8sc  
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public String getSSiteURL() EK=0oy[  
{ (?8i^T?WP=  
return sSiteURL; yUJ#LDW  
} 
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public void setSSiteURL(String value) ]58~b%s  
{ Cy uRj[;B  
sSiteURL = value; aY?VP?BL  
} %n9ukc~$p  
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public String getSFilePath() h M7 SGEV  
{ 9#P~cW?  
return sFilePath; y7:f^4  
} n.8870.BW  
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public void setSFilePath(String value) I*Dj@f`  
{ As>Og
 
sFilePath = value; 8CRbo24"s  
} [zN*P$U]  
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public String getSFileName() Z]Udx  
{ *,CJ 3<>  
return sFileName; lMu9Dp  
} 9y&;6V.'  
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public void setSFileName(String value) 2e1%L,y{W  
{ YYFS ({  
sFileName = value; j0+D99{R  
} e#k rr  
1)h<
)  
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public int getNSplitter() #tHYCSr]  
{ &x\)] i2f  
return nSplitter; 'D`lVUB  
} cq?,v?m  
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+u=VO#IA#  
public void setNSplitter(int nCount) d2i?FT>  
{ dl8f]y#Q  
nSplitter = nCount; wT- -i@@  
} 0_ST2I"Ln  
} \.ie
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/* ~ L%,9  
**Utility.java /v<Gt%3X  
*/ (n.IK/:  
package NetFox; iOhX\@&  
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public class Utility { fA<os+*9i  
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public Utility() qzO
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{ qvo!nr7  
r
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} '[8w8,v(  
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//线程睡眠 v)O].Hd
 
public static void sleep(int nSecond) W0mvwYON[  
{ n(#yGzq  
try{ YU6|/ <8  
Thread.sleep(nSecond); `u_MdB}<x;  
} &F#eYEuy  
catch(Exception e) eQ)*jeD  
{ +RM!j9Rq  
e.printStackTrace (); MHt ~ZVH  
} $v2t6wS,"  
} f ]_ki  
PE6,9i0ee  
//日志 /^jl||'H,:  
public static void log(String sMsg) :oW 16m1`  
{ EX!`Zejf  
System.err.println(sMsg); xbw;s}B  
} q>K3a1x  
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public static void log(int sMsg) Q6URaw#Yt`  
{ )i.pE]!+  
System.err.println(sMsg); ?MSwr_eZH  
} ~ehN%-  
} A:y^9+Da  
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x%H,ta%  
/* |BhL.  
**TestMethod.java /CyFe<t  
*/ 9S9j  
package NetFox; YW~ 9N  
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public class TestMethod { 98 NFJ  
*'H\`@L  
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public TestMethod() )f^^hEIS  
{ ///xx/weblogic60b2_win.exe #b)
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try{ |N6.:K[`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); K% snE7X?)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Yc6.v8a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); bFL2NH5  
fileFetch.start(); =(\BM')l  
} Z Q*hrgQ  
catch(Exception e){e.printStackTrace ();} tmBt[  
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} `S-%}eUv  
+!ljq~%  
n,s7!z/  
public static void main(String[] args) { Dm@_&  
{ b?,%M^9\`  
new TestMethod(); "WtYqXyd  
} ..BP-N)V)  
} j$s/
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