http断点续传简单实现（java)

/* Mlv<r=E  
**SiteFileFetch.java ,Z>wbMJig  
*/ M[aT2A  
package NetFox; v@8S5KJ  
import java.io.*; ?fK^&6pI  
import java.net.*; `,wcQ  
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public class SiteFileFetch extends Thread { [J0*+C9P*  
[kbC'Eh*  
tTotPPZf}  
SiteInfoBean siteInfoBean = null; //文件信息Bean YywEZ?X  
long[] nStartPos; //开始位置 ],8;eq%W)  
long[] nEndPos; //结束位置 `gBD_0<T7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _QR g7  
long nFileLength; //文件长度 8>UKIdp  
boolean bFirst = true; //是否第一次取文件 Fr-[UZ~V  
boolean bStop = false; //停止标志 :GQUM6  
File tmpFile; //文件下载的临时信息 I4)Nb WQ  
DataOutputStream output; //输出到文件的输出流 ?75\>NiR  
dQ:?<zZ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） K7IyCcdB  
public SiteFileFetch(SiteInfoBean bean) throws IOException Kb}MF9?:e  
{ K~c^*;F  
siteInfoBean = bean; 6Wj@r!u  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); JE0?@PI$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x6LjcRS|  
if(tmpFile.exists ()) KNy`Lj)VPY  
{ Hu[
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bFirst = false; 3bWum  
read_nPos(); xE%O:a?S  
} OI+E (nA  
else %drJ p6n%  
{ 3&es]1b  
nStartPos = new long[bean.getNSplitter()]; }wG,BB%N  
nEndPos = new long[bean.getNSplitter()]; #c-b}.R  
} 0pD W _  
1h2H1gy5I3  
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*|mz_cKu  
} |U#DUqw  
wG+=}1X  
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8  
public void run() ;Xqn-R  
{ =f>HiF  
//获得文件长度 B={/nC}G~  
//分割文件 kl" ]Nw'C  
//实例FileSplitterFetch W9dYljnZ8i  
//启动FileSplitterFetch线程 q69H^E=  
//等待子线程返回 Y;} 2'"  
try{ yz?q(]  
if(bFirst) _zq)0\  
{ 1!!\+ c2*  
nFileLength = getFileSize(); MU|{g 5/ )  
if(nFileLength == -1) Ls]@icH0  
{ ?0{yq>fTu  
System.err.println("File Length is not known!"); i^WIr h3a  
} lzEb5mg  
else if(nFileLength == -2) W6vf=I@f  
{ lWbZ=x_0  
System.err.println("File is not access!"); *8PN!^  
} q/$GE,"  
else vv &BhIf3  
{ 1]j^d  
for(int i=0;i<nStartPos.length;i++) > @+#  
{ a5a1'IVq  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !i^]UN   
} }qAVN  
for(int i=0;i<nEndPos.length-1;i++) |Ab{H%  
{ ibXe"X/_  
nEndPos = nStartPos[i+1]; jeq:  
} c5("-xB  
nEndPos[nEndPos.length-1] = nFileLength; ~b Rd)1  
} [EgW/\35  
} g5y;?fqJ  
UFe(4]^  
[Eu];  
//启动子线程 ltoqtB\s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #|Oj]bd(=  
for(int i=0;i<nStartPos.length;i++) nd:E9:  
{
#zt*xS[{0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H-(q#?:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )Vg2Jix,]  
nStartPos,nEndPos,i); gz;&
u)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MLV:U  
fileSplitterFetch.start(); '.Z4 hHX  
} `}gdN};  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4=xq:Tf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "b]#MO}P  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", FQROK4x%"  
nEndPos = " + nFileLength); e0 u,zg+m  
// fileSplitterFetch[nPos.length-1].start(); ]9*;;4Mg  
`XW*kxpm  
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//等待子线程结束 03([@d6<
E  
//int count = 0; mRwT_(;t  
//是否结束while循环 ^P?vkO"pB?  
boolean breakWhile = false; vZu~LW@1  
-f?Ah  
^,TTwLy-t  
while(!bStop) b{M}5~e=B  
{ <'+ %\  
write_nPos(); +{$QAjW(/  
Utility.sleep(500); B76 v}O:  
breakWhile = true; vX;HC'%n  
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for(int i=0;i<nStartPos.length;i++) , ECLqs%  
{ a }'->H  
if(!fileSplitterFetch.bDownOver) pjwaL^  
{ +?[BU<X6u  
breakWhile = false; f8'MP9Lv  
break; .et ^4V3  
} }"_j0ax  
} :$g8Zm,y  
if(breakWhile) 0/ !,Dn  
break; LnFWA0y  
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//count++; 7?nJ4x1  
//if(count>4) 3~Qd)j"<  
// siteStop(); ufrqsv]=  
} Bu3T/m  
KKEN'-3  
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System.err.println("文件下载结束！"); /(?@mnq_  
} 88lxHoPV  
catch(Exception e){e.printStackTrace ();} }gGkV]  
} A\AT0th  
(UYF%MA}"  
?D|\]0eN  
//获得文件长度 k6(r !mc  
public long getFileSize() h2w}wsb0l  
{ |c2xy  
int nFileLength = -1; <G~>~L.E  
try{ $bsH$N#6T  
URL url = new URL(siteInfoBean.getSSiteURL()); S1J<9xqSQ8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 347eis'  
httpConnection.setRequestProperty("User-Agent","NetFox"); Quzo8u  
p $ouh  
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int responseCode=httpConnection.getResponseCode();
,=BLnsg  
if(responseCode>=400) .Cz %:%9  
{ < g|Z}Y  
processErrorCode(responseCode); 2p!"p`b~  
return -2; //-2 represent access is error xHo&[{  
} Pc_VY>Ty  
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2c(aO[%h9  
String sHeader; vq!uD!lr  
7dOyxr"H-  
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for(int i=1;;i++) z42
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{ <rIz Z'D  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /6+NU^  
//Utility.log(in.readLine()); @|\R}k%(  
sHeader=httpConnection.getHeaderFieldKey(i); Uxu\u0*  
if(sHeader!=null) E9}{1A  
{ 8VQ 24r  
if(sHeader.equals("Content-Length")) yx>_scv,T  
{ ycAKK?O*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jS<_ )  
break; tPfFqqT  
} )]43R   
} 7~1IO|4t  
else v [njdP  
break; e]Fp=*#  
} wJ+Aw  
} Ysi g T  
catch(IOException e){e.printStackTrace ();} 9z>z3,ftN  
catch(Exception e){e.printStackTrace ();} EME.h&A\G`  
1HT_  
E?)656F[  
Utility.log(nFileLength); ve6w<3D@  
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return nFileLength; 9`Q<Yy"du  
} fJAnKUF)  
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//保存下载信息（文件指针位置） >~nF=  
private void write_nPos() ^W?Z  
{ <Fz~7W
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try{ (C;I*cv  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HQP}w%8x  
output.writeInt(nStartPos.length); +}xaQc:0|  
for(int i=0;i<nStartPos.length;i++) h"+ `13  
{ MV>$BW  
// output.writeLong(nPos); *QGm//b  
output.writeLong(fileSplitterFetch.nStartPos); 1O/ g&u  
output.writeLong(fileSplitterFetch.nEndPos); zj{r^D$  
} {eS|j=  
output.close(); MrRaU x6z  
} 1.<q3q  
catch(IOException e){e.printStackTrace ();} _<c$)1  
catch(Exception e){e.printStackTrace ();} ^P'{U26  
} 'x"08v$  
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//读取保存的下载信息（文件指针位置） tWeFEVg  
private void read_nPos() >slm$~rv  
{ o=J9  
try{ }J:+{4Yn  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5N[9 vW  
int nCount = input.readInt(); 8flOq"uK^  
nStartPos = new long[nCount]; [U@;\V$  
nEndPos = new long[nCount]; UBv@+\Y8m  
for(int i=0;i<nStartPos.length;i++) v *-0M  
{ vmTs9"ujF,  
nStartPos = input.readLong(); PQN@JaD  
nEndPos = input.readLong(); +HT1ct+dI  
} 3*UR3!Z9 *  
input.close(); Iq7}   
} vQ}6y  
catch(IOException e){e.printStackTrace ();} b75$?_+  
catch(Exception e){e.printStackTrace ();} !TM*o+;  
} "XgmuSQ!  
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$j}OB6^I  
private void processErrorCode(int nErrorCode) \%Ves@hG>  
{ 6z0@I*  
System.err.println("Error Code : " + nErrorCode); Fs_]RfG  
} uc7Eq45  
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d[p;T\?"  
//停止文件下载 FGWN}&K  
public void siteStop() o2z]dTJ}o  
{ Et
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bStop = true; GeszgtK{T  
for(int i=0;i<nStartPos.length;i++) Q\ /uKQ  
fileSplitterFetch.splitterStop(); =@2FX&&E_  
7>XDNI  
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} c~QS9)=E  
} ML;*e"$  
//负责部分文件的抓取 OU5*9_7.  
**FileSplitterFetch.java {@! Kx`(:  
*/ jHN +5=l  
package NetFox; ;Gx)Noo/>  
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import java.io.*; l3Njq^T  
import java.net.*; J^R=dT!  
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public class FileSplitterFetch extends Thread { yRp"jcD  
98=wnWX6$  
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String sURL; //File URL (Yo>Oh4
  
long nStartPos; //File Snippet Start Position RrUBpqA  
long nEndPos; //File Snippet End Position bVP"(H]  
int nThreadID; //Thread's ID r
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boolean bDownOver = false; //Downing is over s,#>m*Rh  
boolean bStop = false; //Stop identical ;%tF58&  
FileAccessI fileAccessI = null; //File Access interface +)zOer,  
`.s({/|[  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException V%$/#sza  
{ A_Frk'{qhB  
this.sURL = sURL; .EM`.  
this.nStartPos = nStart; 8-<:
i  
this.nEndPos = nEnd; "-@[R  
nThreadID = id; 4_Dp+
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 ()&
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} wtje(z5IL  
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public void run() pTIf@n6I  
{ )95f*wte  
while(nStartPos < nEndPos && !bStop) `+6R0Ch  
{ W9NX=gE4  
lHgs;>U$  
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try{ cGjPxG;  
URL url = new URL(sURL); McB[|PmC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {G?N E  
httpConnection.setRequestProperty("User-Agent","NetFox"); y;/VB,4V  
String sProperty = "bytes="+nStartPos+"-"; Zd"^</ S  
httpConnection.setRequestProperty("RANGE",sProperty); : ]C~gc  
Utility.log(sProperty); l;o1 d-n]  
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InputStream input = httpConnection.getInputStream(); jLg9H/w{  
//logResponseHead(httpConnection); A}eOFu`  
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.^B*e6DAD  
byte[] b = new byte[1024]; oudxm[/U  
int nRead; lNSLs"x^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m2AnXY\  
{ 8WnwQ%;m?  
nStartPos += fileAccessI.write(b,0,nRead); )1X#*mCxk  
//if(nThreadID == 1) ZP
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '7O3/GDK  
} Gea\,{E9xA  
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{<<U^<6}  
Utility.log("Thread " + nThreadID + " is over!"); 6gc>X%d`K  
bDownOver = true; ,v"YqD+GC5  
//nPos = fileAccessI.write (b,0,nRead); x.-+[l[1 !  
} / m=HG^!  
catch(Exception e){e.printStackTrace ();} c38D}k^
):  
} 4?B\O`sy.  
} eM8}
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82l~G;.n3  
//打印回应的头信息 K6R.@BMN  
public void logResponseHead(HttpURLConnection con) wmTb97o
 
{ d3xmtG {i  
for(int i=1;;i++) F6z%VWU  
{ 'inFKy'H  
String header=con.getHeaderFieldKey(i); )ut&@]  
if(header!=null) F w?[lS  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M3.do^ss  
Utility.log(header+" : "+con.getHeaderField(header)); A0Qb5e  
else $< JaLS  
break; Yw-G'  
} ov, hI>0!D  
} (!:,+*YY  
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public void splitterStop() v?geCe=ng  
{ Rb'|EiNPw  
bStop = true;
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} JD|=>)  
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} jnn}V~L  
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/* }~L.qG  
**FileAccess.java {tWf  
*//文件访问(定位，写) ^~etm  
package NetFox; ')cMiX\v  
import java.io.*; 9iQq.$A.  
F%RRd/'  
.6Pw|xu`Pw  
public class FileAccessI implements Serializable{ ln6d<; M5  
g%=z_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 iUN Ib
 
RandomAccessFile oSavedFile; qv!2MUw\j  
long nPos; Vh4X%b$TV  
rbWP78  
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public FileAccessI() throws IOException *_d7E   
{ X9V*UXTc  
this("",0); ;>Ib^ov  
} [MUpxOAsd  
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public FileAccessI(String sName,long nPos) throws IOException glDu2a,Q  
{ 3ca (i/c  
oSavedFile = new RandomAccessFile(sName,"rw"); {ttysQ-  
this.nPos = nPos; [DI+~F  
oSavedFile.seek(nPos); ?82xdpg  
} >G25m'&,7  
=%TWX[w  
9dx/hFA  
public synchronized int write(byte[] b,int nStart,int nLen) ) b (B  
{ <eWf<  
int n = -1; ZbdZrE$  
try{ X4~y7  
oSavedFile.write(b,nStart,nLen); b0Ps5G\ u  
n = nLen; #cI{Fe0h  
} 3EPv"f^V  
catch(IOException e) _uy44;zq  
{ w9EOC$|Y  
e.printStackTrace (); &i6),{
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} u7>],<  
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return n; zHM(!\8K  
} ~qTx|",  
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} +nFu|qM}  
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/* n{argI8wF  
**SiteInfoBean.java -&zZtDd F  
*/ Q+{xZ'o"Z  
package NetFox; Rl?_^dPx  
f.KN-f8<F  
YJT&{jYi  
public class SiteInfoBean { OrY/`+Cog  
12b(A+M   
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private String sSiteURL; //Site's URL "#2a8#  
private String sFilePath; //Saved File's Path nFHUy9q  
private String sFileName; //Saved File's Name ^ B fC  
private int nSplitter; //Count of Splited Downloading File )q8pk2  
&5B'nk"  
YYBDRR"  
public SiteInfoBean() (c=6yV@  
{//nSplitter的缺省值为5 2DrP"iGq5  
//default value of nSplitter is 5 z]_wjYn Z  
this("","","",5); 7x|9n  
} ?N*>*"  
?]_$Dcmx  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vc;$-v$&  
{ KQ!8k
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sSiteURL= sURL; )Q&(f/LT  
sFilePath = sPath; BYL)nCc  
sFileName = sName; spH7 /5}  
this.nSplitter = nSpiltter; U]H#MiC!  
) j#`r/  
PUMXOTu]  
} 2lH&  
3
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3nO]Ge"w'n  
public String getSSiteURL() P64PPbP  
{ >* f-Wde  
return sSiteURL; pP&7rRhw  
} O:;w3u7;u  
LM<qT-/qs  
l*(8i ^  
public void setSSiteURL(String value) %rL.|q9
 
{ NX*Q F+  
sSiteURL = value; O`IQ(,yef  
} )-I {^(  
[Kg+^N%+  
u&Yz[)+b=g  
public String getSFilePath() qd ~BnR$=  
{ S6Q  
return sFilePath; -">;-3,K  
} u5`u>.!  
-:+|zF@f  
6jD=F ^jw  
public void setSFilePath(String value) r= `Jn6@  
{ oGnSPI5KGC  
sFilePath = value; we//|fA<  
} cJ=6r :  
$f <(NM6?  
]nn
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public String getSFileName() %D{6[8  
{ i &nSh ]KK  
return sFileName; iy.p n  
} @alK;\  
{L{o]Ii?g  
_}Ac n$  
public void setSFileName(String value) =7=]{Cx[  
{ oq
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sFileName = value; 5uGq%(24  
} nfbR P t  
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#jvtUS\  
public int getNSplitter() w3ResQ   
{ hn GZ=  
return nSplitter; &-)N'  
} 0*3R=7_},o  
/l~p=PK  
Cv.C;H  
public void setNSplitter(int nCount) lfow1WRF  
{ E4jNA}3k+  
nSplitter = nCount; vH@ds k  
} 2*& ^v  
} vm8eZG|  
 ?(1y  
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/* 6xx ?A>:  
**Utility.java 6Pl<'3&  
*/ MAR'y8I  
package NetFox; Gx/Oi)&/  
ASA,{w]  
~,Zc%s~|  
public class Utility { +Mb.:_7'  
dFB]~QEK  
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public Utility() (mpNcOY<D  
{ z43M]P<
 
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x=P\qjSa  
} By!o3}~g  
m+[Ux{$  
//线程睡眠 VscE^'+  
public static void sleep(int nSecond) H/ HMm{4  
{ Ax7[;|2  
try{ rglXs  
Thread.sleep(nSecond); -uG+BraI  
} (y~TL*B  
catch(Exception e) +~$ ]}%  
{ !wVM= z^G  
e.printStackTrace (); sY&IquK^  
} j</: WRA`]  
} Wqw1J=]  
*i%.;Z"  
//日志 %5n_ p^xp  
public static void log(String sMsg) Xl#ggub?  
{ E{`fF8]K  
System.err.println(sMsg); G9cUD[GB  
} *]) `z8Ox  
]h+j)J}[A  
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public static void log(int sMsg) FcU SE  
{ R__OP`!  
System.err.println(sMsg); hL{KRRf>  
} 8OU\V5i[,q  
} 7`'Tbp  
"<1{9  
/(*q}R3Kfo  
/* !l8PDjAE  
**TestMethod.java :crW9+  
*/ 0'C1YvF  
package NetFox; dR,fXQm  
l'_r:b  
$%#!bV  
public class TestMethod { q>+k@>bk@  
JPw.8|V)y  
]{@-HTt  
public TestMethod() Why`ziks  
{ ///xx/weblogic60b2_win.exe p_%Rt"!  
try{ sUQ@7sTj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %
dVZ0dl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); H<,gU`&R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $'M!HJxb  
fileFetch.start(); iqWQ!r^  
} on`3&0,.  
catch(Exception e){e.printStackTrace ();} 6LIJQ  
m;QMQeGz  
hz@bW2S.  
} E ~<JC"]  
rjYJs*#  

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public static void main(String[] args) >|UOz&  
{ %IWPM"  
new TestMethod(); %>{0yEC  
} Tyx_/pJT  
} 3f{3NzN  
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