http断点续传简单实现（java)

/* . hHt+  
**SiteFileFetch.java  ;Fcdjy  
*/ 7}Z.g9<  
package NetFox; ^T'+dGU`  
import java.io.*; R*.XbkW~  
import java.net.*; ~c ;7me.  
@ :Q];rc  
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public class SiteFileFetch extends Thread { COv#dOw  
#@BM1BpQ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Oz^+;P1  
long[] nStartPos; //开始位置 w$A*|^w1  
long[] nEndPos; //结束位置 TCU|k ,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 SZg+5MD;X  
long nFileLength; //文件长度 "V~U{(Z  
boolean bFirst = true; //是否第一次取文件 m#, F%s  
boolean bStop = false; //停止标志 _jH1Mcq  
File tmpFile; //文件下载的临时信息 /7@@CG6b  
DataOutputStream output; //输出到文件的输出流 }^G'oR1LF  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @^Mn PM  
public SiteFileFetch(SiteInfoBean bean) throws IOException "
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{ lO%Z4V_Mj  
siteInfoBean = bean; n$y1kD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vtR<(tOu@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vb: '%^v  
if(tmpFile.exists ()) <| |Lj  
{ `h$6MFC/g  
bFirst = false; 0'^? m$  
read_nPos(); HT A-L>Cee  
} OI %v>ns  
else )
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{ yN{Ybp  
nStartPos = new long[bean.getNSplitter()]; A42At]  
nEndPos = new long[bean.getNSplitter()]; \_@u"+,$W  
} &IT'%*Y:V  
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} .^@+$}   
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public void run() j /-p3#c  
{ )t&|oQ3sVG  
//获得文件长度 C'n 9n!hR  
//分割文件 N$Gx$u3Cd  
//实例FileSplitterFetch b_V)]>v+  
//启动FileSplitterFetch线程 A40 -])'!  
//等待子线程返回 PG<N\  
try{ 7bsW7;C  
if(bFirst) rorzxp{  
{ HH^{,53%  
nFileLength = getFileSize(); .%->  
if(nFileLength == -1) NXeo&+F  
{ V$q%=Sip  
System.err.println("File Length is not known!"); U{>!`RN  
} m{%_5nW  
else if(nFileLength == -2) 5`x9+XvoN  
{ UeHS4cW  
System.err.println("File is not access!"); >z^T~@
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} 8H;TPa  
else DX$`\PA  
{ L8bq3Q'p  
for(int i=0;i<nStartPos.length;i++) "%f>/k;!h.  
{ nkhM1y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); BD4.sd+H,  
}
;i:Uoyi  
for(int i=0;i<nEndPos.length-1;i++) (Egykh>  
{ /6gRoQ%j  
nEndPos = nStartPos[i+1]; /f%u_ 8pV%  
} P]y2W#Rs  
nEndPos[nEndPos.length-1] = nFileLength; DMf^>{[  
} d_5h6Cz4  
} NPB':r-8  
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 .)cOu>  
//启动子线程 &`>*3m(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2vWkAC;   
for(int i=0;i<nStartPos.length;i++) ` |]6<<'iW  
{ 2"__jp:(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rEAPlO.Yp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), JH)&Ca>S  
nStartPos,nEndPos,i); r4D66tF  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _R5^4-Qe  
fileSplitterFetch.start(); Wc,8<Y'   
} >wMsZ+@m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <5$= Ta  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <NJ7mR}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xVl90ak  
nEndPos = " + nFileLength); `gss(o1}  
// fileSplitterFetch[nPos.length-1].start(); x<ENN>mW1  
:A[bqRqe  
ww\/$
|  
//等待子线程结束 "{V,(w8Dt  
//int count = 0; [dzb{M6_  
//是否结束while循环 jNIM1_JjD  
boolean breakWhile = false; ![vc/wuf  
1H[lf B  
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while(!bStop) nI
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{ YF:NRY[i  
write_nPos(); 3ZB;-F5v  
Utility.sleep(500); H/, tE0ZV  
breakWhile = true; b-O4IDIT  
?` `+OH  
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for(int i=0;i<nStartPos.length;i++) TTOd0a  
{ Q'|cOQX  
if(!fileSplitterFetch.bDownOver) G
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{ Hb]7>[L  
breakWhile = false; 9*2hBNp+  
break; !Uj !Oy  
} +Nza@B d  
} gj'ar  
if(breakWhile) %^5$=w  
break; n]o+KT\  
5cfzpOqr0  
v5 9>  
//count++; =  Oq;  
//if(count>4) \2+xMv)8  
// siteStop(); 9J%>2AA  
} S3J6P2P  
,LMme}FFeb  
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System.err.println("文件下载结束！"); DI&xTe9k  
} tNUcmiY  
catch(Exception e){e.printStackTrace ();} #g|j;{P  
} w}(xs)`num  
#qn)Nq(  
F)%;
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//获得文件长度 Ha/\&Z(  
public long getFileSize() 3>jz3>v@  
{ _ssHRbE  
int nFileLength = -1; NeK:[Q@je  
try{ i#-Jl7V[a  
URL url = new URL(siteInfoBean.getSSiteURL()); L,D!T&B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kfVG@o?o  
httpConnection.setRequestProperty("User-Agent","NetFox"); Tbwq_3fK  
Vm.u3KE  
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int responseCode=httpConnection.getResponseCode(); I|LS_m  
if(responseCode>=400) z$<6;2  
{ {?jdPh  
processErrorCode(responseCode); Y"lxh/l$}  
return -2; //-2 represent access is error q2f/#"k  
} [7Kn$OfP  
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Q3/q%#q>  
String sHeader; 9M!_D?+P?  
34?yQX{  
~/#?OLj(T  
for(int i=1;;i++) F9c2JBOM  
{ qB=pp!zQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); sEj:%`l|  
//Utility.log(in.readLine()); 7<tqT @c  
sHeader=httpConnection.getHeaderFieldKey(i);
wM yPR_  
if(sHeader!=null) n$Pv2qw  
{ ( ou:"Y  
if(sHeader.equals("Content-Length")) sXydMk`J  
{ Bdg*XfXXk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M84LbgGM%  
break; a-}%R  
} 54;iLL  
} |knP  
else RXof$2CZS  
break; pts}?   
} cp2fDn  
} d,
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catch(IOException e){e.printStackTrace ();} wYxi
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catch(Exception e){e.printStackTrace ();} ef.lM]cO  
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Utility.log(nFileLength); ,-1$Vh@wM  
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return nFileLength; i&30n#  
} C>u 3n^  
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//保存下载信息（文件指针位置） (gf\VYM-7  
private void write_nPos() KGWENX_U  
{ q%'ovX(dm  
try{ 395o[YZx*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \I'Zc]  
output.writeInt(nStartPos.length); `kv$B3  
for(int i=0;i<nStartPos.length;i++) IL=v[)en4  
{ UxvsSHi  
// output.writeLong(nPos); b(yO  
output.writeLong(fileSplitterFetch.nStartPos); FKx9$B  
output.writeLong(fileSplitterFetch.nEndPos); p%ZiTrA1&D  
} pd;-z  
output.close(); "@?|Vv,vn  
} a"DV`jn  
catch(IOException e){e.printStackTrace ();} :^s7#4%6  
catch(Exception e){e.printStackTrace ();} %~;Q_#CR/K  
} ^hHeH:@  
vX/A9Qi,U.  
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//读取保存的下载信息（文件指针位置） 6C0_. =7#  
private void read_nPos() oto od  
{ 7 b.-&,  
try{ ?xo,)`
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i]-g
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int nCount = input.readInt(); _]S6>  
nStartPos = new long[nCount]; +{%4&T<nHw  
nEndPos = new long[nCount]; 55cldo   
for(int i=0;i<nStartPos.length;i++) Gh|!FRK[$  
{ X@:fW @  
nStartPos = input.readLong(); &0eB@8{N  
nEndPos = input.readLong();  ke#;1  
} 4@V]zfu^Q  
input.close(); L@_">'pR  
} &+j
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catch(IOException e){e.printStackTrace ();} j>Z]J'P  
catch(Exception e){e.printStackTrace ();} >YBpB,WND  
} p<zXuocQ  
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private void processErrorCode(int nErrorCode) _tReZ(Vw  
{ ]18ygqt  
System.err.println("Error Code : " + nErrorCode); pu:D/2R2;k  
} sB
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//停止文件下载 QP[a^5;Tt  
public void siteStop() u,akEvH~a  
{ 8$v7
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bStop = true; W^ :/0WR  
for(int i=0;i<nStartPos.length;i++) ;F""}wzn  
fileSplitterFetch.splitterStop(); !~N4}!X3du  
w~U`+2a3  
rc$!$~|I3Z  
} mVK9NK  
} |3s&Y`x-D  
//负责部分文件的抓取 fBgKX?Y  
**FileSplitterFetch.java 4LEE /  
*/ '^l^g
W/|\  
package NetFox; 0#[f2X62B  
^B5cNEO  
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import java.io.*; (`]*Y(/2G  
import java.net.*; dl6v <  
klJ[ {p  
'98h<(@]  
public class FileSplitterFetch extends Thread { 8}{o2r@  
:#[_Osmf(  
gww^?j#  
String sURL; //File URL _qeuVi=A  
long nStartPos; //File Snippet Start Position VMIX$#  
long nEndPos; //File Snippet End Position H~|%vjH  
int nThreadID; //Thread's ID ARdGh_yJ&  
boolean bDownOver = false; //Downing is over _Hu2[lV  
boolean bStop = false; //Stop identical R5eB,FN  
FileAccessI fileAccessI = null; //File Access interface (Q5@MfK`  
T#n1@FgC  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v$m[#&O^V?  
{ 0BCGJFZ{  
this.sURL = sURL; ix9HSa{d  
this.nStartPos = nStart;
+%Yc4  
this.nEndPos = nEnd; mp,e9Nd;  
nThreadID = id; 7_40_kwJi  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2ly,l[p8  
} *fl{Y(_OO  
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public void run() WjrMd#^  
{ I\upnEKKzZ  
while(nStartPos < nEndPos && !bStop) vA;F]epr!  
{ [DxefYyI  
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M>jBm .  
try{ ],F}}pv  
URL url = new URL(sURL); w2d]96*kQe  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XU_,Z/Yw_  
httpConnection.setRequestProperty("User-Agent","NetFox"); }11`98>B6:  
String sProperty = "bytes="+nStartPos+"-"; %i&/$0.8  
httpConnection.setRequestProperty("RANGE",sProperty); ^
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Utility.log(sProperty); eky(;%Sz  
$}nh[@  
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InputStream input = httpConnection.getInputStream(); 9c6GYWIFt&  
//logResponseHead(httpConnection); h ??C4z  
A!{.|x[S44  
&'(a$S>v  
byte[] b = new byte[1024]; Q+d.%qhc  
int nRead; ?7uKP}1|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Aw4?y[{H  
{ 1/2V.:bg  
nStartPos += fileAccessI.write(b,0,nRead); ,
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//if(nThreadID == 1) H=&/Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WBr:|F+~s  
} hDljY!P>p  
9$+^"ilk  
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Utility.log("Thread " + nThreadID + " is over!"); rg5]`-!=  
bDownOver = true;
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//nPos = fileAccessI.write (b,0,nRead); :4ja@~  
} zr.+'  
catch(Exception e){e.printStackTrace ();} .%?-As  
} H^D 3NuUC  
} `z}vONXpAX  
* -KJh_  
ypD<2z^  
//打印回应的头信息 c6,s+^^  
public void logResponseHead(HttpURLConnection con) l Io9,K
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{ A<SOT>m]  
for(int i=1;;i++) d1V^2Hb?  
{ DD!MGf/  
String header=con.getHeaderFieldKey(i); {N!E5*$Tr  
if(header!=null) EmX>T>~#D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9zZ5Lr^21  
Utility.log(header+" : "+con.getHeaderField(header)); 8QVE_ Eu  
else StU  4{  
break; mDQEXMD  
}  [eNkU">}  
} |rHG%VnBH  
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public void splitterStop() M3Khc#5S(  
{ P+dA~2k  
bStop = true; Y=vVxVI\  
} B;Xoa,  
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} ~u /aOd  
q=6Cc9FN  
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/* khU6*`lQ  
**FileAccess.java 7/H^<%;y  
*//文件访问(定位，写) fJN*s  
package NetFox; 1,"I=  
import java.io.*; ~+O`9&  
K8HIuQ!=  
3CR@' qG-  
public class FileAccessI implements Serializable{ Jd5\&ma  
k"xGA*B|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {=UFk-$=  
RandomAccessFile oSavedFile; h+,'B&=|_  
long nPos; 8Y2xW`  
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public FileAccessI() throws IOException >Z+"`"^o}  
{ Q [rj  
this("",0); q0,kDM66   
} O: ,$%  
}]AT _bh,  
@j O4EEe:  
public FileAccessI(String sName,long nPos) throws IOException v*E(/}<v  
{ 5Sr4-F+@%  
oSavedFile = new RandomAccessFile(sName,"rw"); U1ZIuDg'E  
this.nPos = nPos; KH7VR^;mk  
oSavedFile.seek(nPos); {?E<](+0  
} E{tx/$f  
!^m%O0DT  
u!Xb?:3uj  
public synchronized int write(byte[] b,int nStart,int nLen) & _; y.!  
{ 2w+U$6e C  
int n = -1; lnS(&`oh\=  
try{ xfjd5J7'  
oSavedFile.write(b,nStart,nLen); NJtQx2Sd'H  
n = nLen; wV(AT$  
} _
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catch(IOException e) +l`65!"  
{ 'Qa5n\HX$  
e.printStackTrace (); eD%HXGe  
} w OI^Q~  
-fE.<)m=!  
/~De2mq1  
return n; bEm7QgV{X  
} *5_V*v6  
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} 7R}9oK_I  
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/F.Wigv  
/* ,P{mk%=9  
**SiteInfoBean.java $ a?  
*/ e}'gvm  
package NetFox; {C3U6kKs;R  
Ko6^iI1  
EIjI!0j  
public class SiteInfoBean { MJ`N,E[  
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v2Bzx/F:  
private String sSiteURL; //Site's URL dBSbu=^$)  
private String sFilePath; //Saved File's Path (hIF]>,kl  
private String sFileName; //Saved File's Name jjRUL.  
private int nSplitter; //Count of Splited Downloading File pY@Y?Jj  
*z'8
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"wAf.=F  
public SiteInfoBean() oH^(qZ8W  
{//nSplitter的缺省值为5 As~(7?]r  
//default value of nSplitter is 5 w~z[wmOkp  
this("","","",5); #2RiLht  
} /kgeV4]zR  
G O{.9_2  
*wuqa)q2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !*aPEf270  
{ u:&o}[  
sSiteURL= sURL; ~e `Bq>  
sFilePath = sPath; #`(WUn0H?  
sFileName = sName; ]PWDE"  
this.nSplitter = nSpiltter; {ox2Tg?  
M*sR3SZ  
O:'?n8rWL  
} +vW)vS[  
:w`3cwQ  
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public String getSSiteURL() %<"}y$J  
{ 6sJw@OaJ  
return sSiteURL; ?^i1_v7 Bi  
} 0V$k7H$Z  
4[yIOs  
?WUF!Jk  
public void setSSiteURL(String value) +-<}+8G;  
{ z0%\OhuCcf  
sSiteURL = value; iYJZvN  
} 1TS0X:TCn  

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public String getSFilePath() `Out(Hn  
{ 
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return sFilePath; ,1oQ cC  
} slu(SmQ  
0*;O?T  
E<E3&;qD  
public void setSFilePath(String value) HDVW0QaMu  
{ 0v)bA}k  
sFilePath = value; %zBCq"y  
} Es5f*P0  
m/B6[  
2f>PO +4S{  
public String getSFileName() >&,[H:Z  
{ ,](:<A)W&  
return sFileName; _;
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} OFk8>"|  
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q%(EYM5Y  
public void setSFileName(String value) P>i%7:OMZA  
{ 7ZxaPkIu&%  
sFileName = value; m2~&#c\  
} Wy .IcWK  
&;i "P  
WW
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public int getNSplitter() ,Lpixnm]  
{ 0AK,&nbF  
return nSplitter; q:\g^_!OGA  
} {q%Sx*k9[  
{@W9
3=Vq8  
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public void setNSplitter(int nCount) hRC
 
{ h `}}  
nSplitter = nCount; *&BnF\?m  
} V7d)S&*V  
} *NFg;<:j  
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cD*}..-/4  
/* =GlVccc  
**Utility.java Ub1hHA*)  
*/ %`MQmXgM  
package NetFox; #Z+i~t{e(  
<"N_j]wD  
sm,VYYs  
public class Utility { 4y:]DC"  
kOOGw:/  
9,uhfb^]  
public Utility() Vj<:GRNQ,d  
{ e^p +1-B  
x8Loyt_C  
{S/yL[S.  
} 6!x&LoM  
vo>d!rVCV  
//线程睡眠 C%d_@*82  
public static void sleep(int nSecond) `Z:R Ce^  
{ N6K*d` o  
try{ Hnknly  
Thread.sleep(nSecond); r{\1wt  
} 7SDFz}  
catch(Exception e) &|>S|  
{ \B F*m"lz  
e.printStackTrace (); 1"Z@Q`}  
} 4iAZ+l5&  
} 'c2W}$q  
XU!2YO)t;!  
//日志 -9N@$+T  
public static void log(String sMsg) S/|,u`g-  
{ gE#>RM5D  
System.err.println(sMsg); j',W 64  
} k@zy  
v+p{|X-  
0a8/B>  
public static void log(int sMsg) {3;AwhN0H  
{ ;g{qYj_  
System.err.println(sMsg); vEf4HZ&w  
} hfpJ+[  
} XL#[%X9  
{{V8;y  
#^m0aB7r  
/* =qN2Xg/  
**TestMethod.java rpeJkG@+  
*/ SJD@&m%?[  
package NetFox; 9T#;,{VQ  
P96pm6H_;  
+]=e;LN$0  
public class TestMethod { EY*(Bw  
R1Sy9x .  
C{TA.\   
public TestMethod() hxce\OuU0h  
{ ///xx/weblogic60b2_win.exe %ZHP2j %~  
try{ "KcA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); n>@oBG)!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >WY#4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); DN4$Jva  
fileFetch.start(); r0p w_j  
} YK|bXSA[  
catch(Exception e){e.printStackTrace ();} [MuEoWrq(}  
),%6V5a+E  
wFG3KzEq ~  
} 8XbA'% o  
U qG .:@T  
{vAE:W.s  
public static void main(String[] args) 3?Y2L  
{ 9x,RvWTb  
new TestMethod();  >S$Z  
} ss;R8:5  
} 8~5cJPi6  
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