http断点续传简单实现（java)

/* <,r|*pkhp~  
**SiteFileFetch.java -_bnGY%,  
*/ s\k4<d5  
package NetFox; H6Mqy}4W  
import java.io.*; E,S[3+  
import java.net.*; 6V"|  
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R aVOZ=^-  
public class SiteFileFetch extends Thread { hmRnr=2N  
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SiteInfoBean siteInfoBean = null; //文件信息Bean v-k~Q$7
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long[] nStartPos; //开始位置 PgeC\#;9  
long[] nEndPos; //结束位置 -K 7jigac  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 l
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long nFileLength; //文件长度 b'!t\m  
boolean bFirst = true; //是否第一次取文件 OlW|qj  
boolean bStop = false; //停止标志 ''{REFjK7  
File tmpFile; //文件下载的临时信息 vr,8i7*0  
DataOutputStream output; //输出到文件的输出流 [z2XK4\e1T  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） g>m)|o'  
public SiteFileFetch(SiteInfoBean bean) throws IOException _6b?3[Xz  
{ \{Qd  
siteInfoBean = bean; Kw`{B3"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0W92Z@_GY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,cgFdOM.  
if(tmpFile.exists ()) e;+6U"Jx*  
{ n9 LTrhLqp  
bFirst = false; x)Y?kVw21"  
read_nPos(); Wchu-]  
} toq/G,N Q  
else @H{QHi  
{ NUlp4i~Q  
nStartPos = new long[bean.getNSplitter()]; [Eeanl&x>  
nEndPos = new long[bean.getNSplitter()]; ewo]-BQS  
} i++a^f  
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} n(i Uc1Y  
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public void run() }?KvT$s  
{ g[oa'.*OB  
//获得文件长度 ~AVn$];{  
//分割文件 MI: rH  
//实例FileSplitterFetch -/x=`S*  
//启动FileSplitterFetch线程 .!fhy[%o:D  
//等待子线程返回 03ol6y )C  
try{ -B`Nkc  
if(bFirst) scf.>K2  
{ (E{>L).~  
nFileLength = getFileSize(); q*L>MV  
if(nFileLength == -1) (Dy6I;S  
{ >@b]t,rrK  
System.err.println("File Length is not known!"); 9H~2 iW,Q;  
} jGg,)~)Y  
else if(nFileLength == -2) wzXIEWJ  
{ ?QDHEC62  
System.err.println("File is not access!"); y*F !k{P  
} wbIgZ]o!/;  
else L}~"R/iWCT  
{ [>2iz  
for(int i=0;i<nStartPos.length;i++) s6q6)RD"  
{ I_1(jaY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I7@|{L1|FB  
} jR1o<]
?  
for(int i=0;i<nEndPos.length-1;i++) J0ysZ]  
{ lOp7rW]$  
nEndPos = nStartPos[i+1]; Oe)d|6=  
} &kR*J<)V  
nEndPos[nEndPos.length-1] = nFileLength; 8t1XZ  
} S55h}5Y  
} \;!}z3Ww  
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//启动子线程 i;flK*HOZ9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -w dbH`2Z"  
for(int i=0;i<nStartPos.length;i++) e^LjB/<Th  
{ WE{fu{x  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XIGz_g;#'w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H*m3i;"4p\  
nStartPos,nEndPos,i); B
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kB)u@`</mV  
fileSplitterFetch.start(); R@X65o  
} V< Ib#rd'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *:5S*E&}V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K2XRKoG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :17Pc\:DS  
nEndPos = " + nFileLength); ~WjK'N4n5  
// fileSplitterFetch[nPos.length-1].start(); X[ 6#J  
OH\(;RN*  
vGCvJ*4!  
//等待子线程结束 0P5s'2w  
//int count = 0;  )>=!</@  
//是否结束while循环 oimM)Yo  
boolean breakWhile = false; F@tfbDO?  
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while(!bStop) &E]<dmR  
{ ;u8a%h!  
write_nPos(); S-f .NC}:i  
Utility.sleep(500); Ybkydc  
breakWhile = true; *8bj3A]vf  
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for(int i=0;i<nStartPos.length;i++) [.(,vn?6  
{ 33=lR-N#  
if(!fileSplitterFetch.bDownOver) EV'i/*v}\  
{
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breakWhile = false; S4_C8  
break; gkM Q=;Nn  
} $} @gR] Z  
} "5!T-Z+F  
if(breakWhile) \{a!Z&df  
break; 6!`GUU  
n)Zu>  
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//count++; 45,):U5  
//if(count>4) sTxgU !_  
// siteStop(); qs%UJ0tR  
} Yyr qO^9m  
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!X[P)/?b0+  
System.err.println("文件下载结束！"); ,Y4>$:#n/  
} UhKd o  
catch(Exception e){e.printStackTrace ();} d=p=eUd2  
} Nz77" kC  
dq{+-XaEk  
)H>?K0I  
//获得文件长度 Kqz+:E8D  
public long getFileSize() @<jm+f"MP  
{ j"A<qI  
int nFileLength = -1; rJTYCe1*  
try{ `-!kqJ  
URL url = new URL(siteInfoBean.getSSiteURL()); I7#^'/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3xz|d`A  
httpConnection.setRequestProperty("User-Agent","NetFox"); *EwDwS$$  
nWes,K6T  
HU/2P`DGP  
int responseCode=httpConnection.getResponseCode(); fm^J-  
if(responseCode>=400) B'e@RhU;  
{ x*sDp3f[*  
processErrorCode(responseCode); .0rTk$B  
return -2; //-2 represent access is error 0j!xv(1  
} M2$
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String sHeader; v:P=t2q  
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for(int i=1;;i++) 'T|EwrS j  
{ !Ln 'Mi_B  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hD[r6c  
//Utility.log(in.readLine()); 8OMMV,QF  
sHeader=httpConnection.getHeaderFieldKey(i); (;;.[4,y  
if(sHeader!=null) zsLMROo3  
{ f5Hv![x  
if(sHeader.equals("Content-Length")) >"+ho  
{ 5\EnD,y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R,s}<N$  
break; r1Hh @sxn  
} 4TTrHs  
} +c8t~2tuN  
else ^`[<%.  
break; (5;nA'  
} 4H^ACw  
} 2^=8~I!n&  
catch(IOException e){e.printStackTrace ();} #+N_wIP4  
catch(Exception e){e.printStackTrace ();} Ifokg~X~G  
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{<$tEj:  
Utility.log(nFileLength); "L;@qCfhO  
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return nFileLength; M
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} +w7U7" xQ  
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//保存下载信息（文件指针位置） Eg&:yF}?(  
private void write_nPos() Uq @].3nf  
{ *kpP)\P  
try{ @u`W(Ow  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OFBEJacy  
output.writeInt(nStartPos.length); }.pqV X{d  
for(int i=0;i<nStartPos.length;i++) PhPe7^  
{ cs7^#/3<  
// output.writeLong(nPos); 2$MoKOx8$  
output.writeLong(fileSplitterFetch.nStartPos); bIlNA)g  
output.writeLong(fileSplitterFetch.nEndPos); &uF~t |!c  
} d>NO}MR  
output.close(); d&AO4^  
} +'Y?K]zbt  
catch(IOException e){e.printStackTrace ();} 5JEOLPS
  
catch(Exception e){e.printStackTrace ();} 5rfDm  
} J[0

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//读取保存的下载信息（文件指针位置） pY[b[ezb  
private void read_nPos() YR? E z<p  
{ OSfT\8YA  
try{ ,(-V<>/*.|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~1E!Co  
int nCount = input.readInt(); ce#Iu#qT  
nStartPos = new long[nCount]; xAl8e  
nEndPos = new long[nCount]; 4x&Dz0[[S  
for(int i=0;i<nStartPos.length;i++) <;yS&8  
{ +$#<gp"  
nStartPos = input.readLong(); nW^h +  
nEndPos = input.readLong(); "O-X*>?f  
} EADN   
input.close(); #t;]s<  
} )hl7)~S<  
catch(IOException e){e.printStackTrace ();} 10h;N[  
catch(Exception e){e.printStackTrace ();} 8V}|(b#  
} \NMqlxp2  
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private void processErrorCode(int nErrorCode) .%)uCLZr$  
{ x/CM)!U)  
System.err.println("Error Code : " + nErrorCode); hJ]Oa7r  
} |/H?\]7  
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3!\h'5{  
//停止文件下载 fI`gF^u(  
public void siteStop() [|YvVA  
{
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bStop = true; vK@UK"m  
for(int i=0;i<nStartPos.length;i++) NiWAJ]Z  
fileSplitterFetch.splitterStop(); zwU[!i)  
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} ?}v/)hjp=?  
} 99`w'Nlk  
//负责部分文件的抓取 {d*OJ/4  
**FileSplitterFetch.java j5Da53c#^  
*/ 4_iA<}>|  
package NetFox; 1<1+nGO  
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import java.io.*; fz`)CWo:  
import java.net.*; 2"?DaX  
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public class FileSplitterFetch extends Thread { m7y[Y  
;5L^)Nyd  
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String sURL; //File URL i0$*):b  
long nStartPos; //File Snippet Start Position /hu>MZ(\  
long nEndPos; //File Snippet End Position \QC{38}  
int nThreadID; //Thread's ID g hmn3  
boolean bDownOver = false; //Downing is over -e}(\  
boolean bStop = false; //Stop identical ` 6*]cn#(  
FileAccessI fileAccessI = null; //File Access interface lH`TF_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2aCf?l(  
{ jk&xzJH.  
this.sURL = sURL; gN/>y1{a  
this.nStartPos = nStart; wEM=Tr/h  
this.nEndPos = nEnd; " (O3B  
nThreadID = id; 2/r8%Sq  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,3 /o7'  
} Sx QA*}N  
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2[Lv_<i|  
public void run() *l{epum;  
{ Nj3iZD|  
while(nStartPos < nEndPos && !bStop) n<j+KD#a  
{ Pb>/b\&JS  
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try{ KS93v9|  
URL url = new URL(sURL); 3sdL\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  {
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httpConnection.setRequestProperty("User-Agent","NetFox"); y)&K9 I  
String sProperty = "bytes="+nStartPos+"-"; X.;VZwT+  
httpConnection.setRequestProperty("RANGE",sProperty); vE'{?C=EM  
Utility.log(sProperty); M Zz21H  
YIg43Av  
}R#W<4:  
InputStream input = httpConnection.getInputStream(); Ve|:k5z  
//logResponseHead(httpConnection); f0sGE5  
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byte[] b = new byte[1024]; \H:T)EV
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int nRead; J??AU0vh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $ch`.$wx  
{ hI!BX};+}  
nStartPos += fileAccessI.write(b,0,nRead); ]}N01yw|s  
//if(nThreadID == 1) )h]#:,pm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =?.oH|&\h  
} uStAZ~b\  
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]$Z:^"JS3  
Utility.log("Thread " + nThreadID + " is over!"); s2G9}i{  
bDownOver = true; Y /_CPY  
//nPos = fileAccessI.write (b,0,nRead); LZe)_9$  
} Na/Y1RW  
catch(Exception e){e.printStackTrace ();} iOURS  
} q/U-6A[0  
} Pn OWQ8=  
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f; |fS~  
//打印回应的头信息 vHpw?
(]
 
public void logResponseHead(HttpURLConnection con) (?\+
  
{ 5\bGCf  
for(int i=1;;i++) g) oOravV  
{ Mz6(M,hkq  
String header=con.getHeaderFieldKey(i); 6EyPZ{  
if(header!=null) ZK^cG'^2|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &}k7iaO  
Utility.log(header+" : "+con.getHeaderField(header)); I61S0lz/  
else g) u%?T  
break; Vz/w.%_g  
} _=s9o/Cn]  
} N~O
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2r!ltG3}  
public void splitterStop() Om0$6O  
{ zW%Em81Wd  
bStop = true; H\ejW@<;h  
} M/Yr0"%Q<.  
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D:/ n2_  
} h
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/* :9UgERjra  
**FileAccess.java J/4T=:\  
*//文件访问(定位，写) c,2& -T}  
package NetFox; Lkm-<  
import java.io.*; tf~B,?  
w_56y8Pd4  
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public class FileAccessI implements Serializable{ ;3cbXc@]  
#_ |B6!D!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^r\rpSN  
RandomAccessFile oSavedFile; \tI%[g1M  
long nPos; ~U]g;u  
;AEfU^[  
LBK{-(%  
public FileAccessI() throws IOException 2@zduL'do_  
{ Sf,z  
this("",0); pD$4nH4KST  
} I
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public FileAccessI(String sName,long nPos) throws IOException k <oB9J  
{ |NfFe*q0;8  
oSavedFile = new RandomAccessFile(sName,"rw"); ^Qs}2%  
this.nPos = nPos; `Y?VQ~ci
>  
oSavedFile.seek(nPos); K.)!qkW-%S  
} >S +}  
^ F]hW  
.*z
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public synchronized int write(byte[] b,int nStart,int nLen) r<+C,h;aww  
{ k5S;G"iJ  
int n = -1; 2!/Kt O)i^  
try{ wGAr
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oSavedFile.write(b,nStart,nLen); lhN@,q  
n = nLen; V*4Z.3/E5  
} &F&`y  
catch(IOException e) Ht Fr(g\"$  
{ ,&t+D-s<f  
e.printStackTrace (); !!1?2ine  
} dE7x SI  
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return n; 6Xvpk1
  
} ]<f)Rf">:`  
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} h:%,>I%{  
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/* 7=l~fKu  
**SiteInfoBean.java \]tBwa  
*/ u;`]U$Qq9  
package NetFox; OpUfK4U)  
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)/;KxaKt  
public class SiteInfoBean { p/h\QG1   
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private String sSiteURL; //Site's URL &BVH
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private String sFilePath; //Saved File's Path Lzh8-d=HQ  
private String sFileName; //Saved File's Name \H] |5fp*  
private int nSplitter; //Count of Splited Downloading File uAO!fE}CJ  
>f]/VaMH{  
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public SiteInfoBean() .a*?Pal@@  
{//nSplitter的缺省值为5 U: 9&0`k(  
//default value of nSplitter is 5 ,MY7h8V/  
this("","","",5); %6m/ve  
} :;k?/KU7  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ZoG@"vr2  
{ > G\0Z[<v,  
sSiteURL= sURL; gQ+]N*.  
sFilePath = sPath; \`n(JV  
sFileName = sName; jRK}H*uem  
this.nSplitter = nSpiltter; Y <6|z3  
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} k%.v`H!  
\]ib%,:YU  
2.q Zs8&  
public String getSSiteURL() hY"eGaoF"  
{ Ni_H1G  
return sSiteURL; @ st>#]i4  
} [?]N GTr#  
c#OxI*,+/  
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public void setSSiteURL(String value) h3MdQlJ&  
{ :@L7RZ`_  
sSiteURL = value; 72<9xNcB!}  
} Kr
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public String getSFilePath() N1t4o~  
{ )&c2+Y@  
return sFilePath; C;BO6$*_e  
} a"#t'\  
;d?BVe?  
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public void setSFilePath(String value) S:xXD^n#H  
{ L!Jx`zM^  
sFilePath = value;
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} e={O&9Z  
aHhLz>H'  
 ?8>a;0  
public String getSFileName() =E-x0sr?  
{ XcJ5KTn  
return sFileName; pS?D~0Nb  
} (XZ[-M7  
GBz?$]6  
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public void setSFileName(String value) uo:RNokjJ  
{ $fb%?n{  
sFileName = value; jFSR+mP!  
} ]cRvdUGv  
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public int getNSplitter() Ac_P^  
{ -laH^<jm5  
return nSplitter; +ai3   
} N.|F8b]v  
T8 FW(Gw#  
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public void setNSplitter(int nCount) l6'KIg  
{ 1mFH7A($  
nSplitter = nCount; '(]Wtx%9"  
} Wv4$Lgr  
} (:iMs) iO{  
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2[lP,;!  
/* }?m0bM  
**Utility.java rZI63S  
*/ g@H<Q('fJ  
package NetFox; @rhS[^1wi+  
1jC85^1Taq  
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public class Utility { Q& [!+s:2J  
H I9/  
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public Utility() .][yH[F  
{ W{NWF[l8O?  
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} '/GB8L  
tQ}GTqk  
//线程睡眠 g~<[;6&{  
public static void sleep(int nSecond) 1d<?K7%^  
{ 2a@X-Di  
try{ iwnGWGcuS  
Thread.sleep(nSecond); I Fw7?G,  
} C|y^{4|R  
catch(Exception e) 7w73,r/D8A  
{ e1[ReZW  
e.printStackTrace (); -Mo4`bN  
} |q4=*Xq  
} g$Tsht(rHD  
.-$3I|}X=  
//日志 cqU6 Y*n  
public static void log(String sMsg) ?y|&Mz'XJ(  
{ q/?*|4I  
System.err.println(sMsg); Y%}&eN$r  
} t[|rp&xG  
ivo3pibk%  
2I:P}!  
public static void log(int sMsg) $_JfM^w  
{ 5bb#{?2i  
System.err.println(sMsg); oyVT  
} jTwSyW  
} bB@=J~l4  
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/* cc${[yj
)  
**TestMethod.java \d
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*/ .#y#u={{l  
package NetFox; C b'|  
\BBs;z[/  
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public class TestMethod { zFOtOz`9H  
>s%Db<(P=  
fBX@ MedC  
public TestMethod() %:
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{ ///xx/weblogic60b2_win.exe a;$V;3C{b&  
try{ 2IJniS=[>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lLQcyi0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -3(*4)h7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PE{<'K\g  
fileFetch.start(); 1 F:bExQ  
} x|Uwk=;X|s  
catch(Exception e){e.printStackTrace ();} )d[n-Si  
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} {X?Aj >l  
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@zGF9O<3,@  
public static void main(String[] args) M8lw; (  
{ n\9IRuYO  
new TestMethod(); l_k:OZ  
}  XY)X-K$  
} Q'U!  
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