http断点续传简单实现（java)

/* 'pj*6t1~  
**SiteFileFetch.java YJGP8  
*/ i"#pk"@`  
package NetFox; Yz)+UF,  
import java.io.*; 4OeH}@a  
import java.net.*; v`hn9O  
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public class SiteFileFetch extends Thread { BEtFFi6ot  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [2{2w68D!  
long[] nStartPos; //开始位置 8 qlQC.VA[  
long[] nEndPos; //结束位置 xc}kDpF=g  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m$bYx~K  
long nFileLength; //文件长度 ^P|Zze zwU  
boolean bFirst = true; //是否第一次取文件 )=nB32~J"  
boolean bStop = false; //停止标志 }Qa  
File tmpFile; //文件下载的临时信息 BdB9M8fM  
DataOutputStream output; //输出到文件的输出流 6<fcG  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n"w>Y)C(X)  
public SiteFileFetch(SiteInfoBean bean) throws IOException '""s%C+  
{ .B?fG)'WsF  
siteInfoBean = bean; cHC1l  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); GXi)3I%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _MWW  
if(tmpFile.exists ()) 7jw5'`;)"  
{ )>tT""yEl  
bFirst = false; %/2OP &1<  
read_nPos(); l?A~^4(5a/  
} []doLt;J  
else s.^+y7$  
{ Th X6e  
nStartPos = new long[bean.getNSplitter()]; .oM;D~(=9  
nEndPos = new long[bean.getNSplitter()]; 5,|of{8  
} lWDSF]ZYV  
}Te+Rv7{E  
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} lS|F&I5j  
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public void run() &Qe2 }e$  
{ `ff@f]|3^  
//获得文件长度 >}B53.;.k  
//分割文件 YJ+l \Wb}  
//实例FileSplitterFetch 7+Er}y>  
//启动FileSplitterFetch线程 F. I\?b  
//等待子线程返回 EMPujik-  
try{ 9"?;H%.  
if(bFirst)
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{ XMzQ
8|]  
nFileLength = getFileSize(); P{HR='2  
if(nFileLength == -1) JkI|Ojmm/  
{ hcpe~spz9|  
System.err.println("File Length is not known!"); .pG`/[*a  
} GL _hRu  
else if(nFileLength == -2) J| 1!4R~  
{ `YY07(%  
System.err.println("File is not access!"); FE1'MUT_  
} Y.q$"lm7k  
else F-XMy>9  
{ *^KEb")$  
for(int i=0;i<nStartPos.length;i++) <sn,X0W  
{ PZY6 I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); X/buz  
} tkmzOc H  
for(int i=0;i<nEndPos.length-1;i++) 3e>U(ES  
{ e~SRGyIww  
nEndPos = nStartPos[i+1]; r)B55;*Fh  
} L#WGOl  
nEndPos[nEndPos.length-1] = nFileLength; ^A=2#
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} WD5jO9Oai  
} 9rIv-&7'm  
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//启动子线程 ^x Z=";eq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; PzT@q\O  
for(int i=0;i<nStartPos.length;i++) --k!KrL  
{ :Dfl,=S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x_9#:_S'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ltyhYPS  
nStartPos,nEndPos,i); s)Xz}QPK.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ']d(m?  
fileSplitterFetch.start(); vsPIvW!V  
} S_ra8HY8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >`|Wg@_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <?:h(IZe[  
nEndPos = " + nFileLength);
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// fileSplitterFetch[nPos.length-1].start(); <nK@+4EH"o  
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//等待子线程结束 a5(9~.9  
//int count = 0; Z{gDEo)  
//是否结束while循环 |WNI[49  
boolean breakWhile = false; F$'po#  
KO/#
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^)o]hE|  
while(!bStop) @V&HE:P  
{ _Ea1;dJmq  
write_nPos(); IpM"k)HR  
Utility.sleep(500); )NTpb  
breakWhile = true; XjmAM/H4  
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for(int i=0;i<nStartPos.length;i++) VF+g+~  
{ UGvUU<N|N  
if(!fileSplitterFetch.bDownOver) ,Xg^rV~]  
{ (,|eE)+  
breakWhile = false; Bc`L]<  
break; a'?LC)^  
} YDZB$?&a  
} c[;A$P= 8.  
if(breakWhile) xiL+s-  
break; sGh TP/  
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//count++; a/3yn9`sQ  
//if(count>4) "yl6WG#J  
// siteStop(); >jnx2$  
} :;IZ|hU  
"Z~@"JLb%  
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System.err.println("文件下载结束！"); }2^qM^,0  
} We*uZ?+  
catch(Exception e){e.printStackTrace ();} %$bhg&}  
} NBAOVYK  
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//获得文件长度 e.Q'l/g  
public long getFileSize() %s;5  
{ s2F[v:|Wq  
int nFileLength = -1; /XNC^!z6Js  
try{ -S&d5(
R  
URL url = new URL(siteInfoBean.getSSiteURL()); Zqv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,s6lB0  
httpConnection.setRequestProperty("User-Agent","NetFox"); B,` `2\B  
N7GZ'-t^Er  
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int responseCode=httpConnection.getResponseCode(); 3Vk\iJ
  
if(responseCode>=400) -~*kAh  
{ !Q,Dzv"7  
processErrorCode(responseCode); cY+n 6k5  
return -2; //-2 represent access is error "*S_wN%  
} XsSDz}dg  
fo<nk|i  
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String sHeader; E 0OHl  
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for(int i=1;;i++) :*R+ee,&-  
{ A+}O~,mxP8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |x=(}g  
//Utility.log(in.readLine()); ,#9i=gp  
sHeader=httpConnection.getHeaderFieldKey(i); UMMGT6s,E8  
if(sHeader!=null) IR&b2FTcU  
{ n\$.6 _@x  
if(sHeader.equals("Content-Length")) L+mHeS l  
{ k4!p))ql  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); FTzc,6  
break; F^lau f  
} b/tcD r  
} Zrew}0  
else iAeq%N1(0  
break; BQv*8Hg B6  
} @y6^/'  
} aU$80  
catch(IOException e){e.printStackTrace ();} #WE lL2&  
catch(Exception e){e.printStackTrace ();} i3)7Qa[  
B7S)L#l_\  
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Utility.log(nFileLength); iszVM  
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return nFileLength; bn=7$Ax  
} .eCUvX`$  
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//保存下载信息（文件指针位置） %6&c3,?U\n  
private void write_nPos() &KV$x3  
{ VkId6k:>6C  
try{ 31F^38  
output = new DataOutputStream(new FileOutputStream(tmpFile)); DD6K[\  
output.writeInt(nStartPos.length); E{\T?dk1$  
for(int i=0;i<nStartPos.length;i++) 6aWNLJ@  
{ V<U9Pj^?^  
// output.writeLong(nPos); q AsTiT6r  
output.writeLong(fileSplitterFetch.nStartPos); `'9t^
6mk  
output.writeLong(fileSplitterFetch.nEndPos); 5!57<n  
} n:}'f- :T  
output.close(); er@.<Dc  
} l=a<=i  
catch(IOException e){e.printStackTrace ();} hn$jI5*`  
catch(Exception e){e.printStackTrace ();} YWDd[\4  
} II\}84U2 .  
?
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//读取保存的下载信息（文件指针位置） M?DXCsZ,)s  
private void read_nPos() G*-7}7OAs  
{ BDX>J3h  
try{ 2Y;iqR  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a!&m\+?  
int nCount = input.readInt(); &$h#9  
nStartPos = new long[nCount]; dd@ D s  
nEndPos = new long[nCount]; vtzbF1?O  
for(int i=0;i<nStartPos.length;i++) 6rlM\k@!  
{ b86c[2  
nStartPos = input.readLong(); ;Wn0-`_1,  
nEndPos = input.readLong(); y+7A?"s)  
} >QBDxm
  
input.close(); iE]^6i  
} @y|JIBBRc  
catch(IOException e){e.printStackTrace ();} :Yi 4Ia  
catch(Exception e){e.printStackTrace ();} "msPH<D  
} ir_X65l/2  
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<[17&F0  
private void processErrorCode(int nErrorCode) !3"Hn  
{ D6'-c#  
System.err.println("Error Code : " + nErrorCode); o KY0e&5  
} 8vj]S5  
7+$P6[*  
n]K{-C;  
//停止文件下载 +1eb@bX  
public void siteStop() wFJ*2W:  
{ xoQqku"vn  
bStop = true; iH-(_$f;  
for(int i=0;i<nStartPos.length;i++) 4EhWK;ra  
fileSplitterFetch.splitterStop(); I=k`VId:  
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} n,p \~Tu,  
} ^>s{o5H&  
//负责部分文件的抓取 hgdr\ F  
**FileSplitterFetch.java ?~;q r  
*/ LEAU3doK;  
package NetFox; LOk J  
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import java.io.*; pQ`S%]k.<  
import java.net.*; 't475?bY  
:|=Xh"l"  
@[;$R@M_3  
public class FileSplitterFetch extends Thread { OuB[[L  
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String sURL; //File URL ItG|{Bo  
long nStartPos; //File Snippet Start Position n&E/{o(  
long nEndPos; //File Snippet End Position "ZG2olOqLI  
int nThreadID; //Thread's ID [t]q#+Zs  
boolean bDownOver = false; //Downing is over UFj/Y;  
boolean bStop = false; //Stop identical 2K2*UC`f  
FileAccessI fileAccessI = null; //File Access interface s~I#K[[5  
(2/i1)Cq  
}G<A$*L1  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException aY%{?8PsB  
{ #o(@S{(NZ  
this.sURL = sURL; +F^X1  
this.nStartPos = nStart; /$UWTq/C7  
this.nEndPos = nEnd; l
^v,X%{Iz  
nThreadID = id; eS2VLVxu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wOR#sp&  
} =jvN8R*[  
^;cJjl'=  
2VkA!o4nP  
public void run() K$-|7tJon  
{ D!bi>]Yd  
while(nStartPos < nEndPos && !bStop) <-!'V,c  
{
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try{ nY?X@avo>  
URL url = new URL(sURL); n:%A4*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !jN$U%/,%.  
httpConnection.setRequestProperty("User-Agent","NetFox"); X+//$J  
String sProperty = "bytes="+nStartPos+"-"; JvD`RUh  
httpConnection.setRequestProperty("RANGE",sProperty); Cx8  H  
Utility.log(sProperty); .Mzrj{^Y  
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InputStream input = httpConnection.getInputStream();  83:qIfF  
//logResponseHead(httpConnection); \3cg\Q+~  
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byte[] b = new byte[1024]; {ALOs^_-  
int nRead; TK#-;p_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Oz.Zxw  
{ \LDcIK=  
nStartPos += fileAccessI.write(b,0,nRead); Wu693<  
//if(nThreadID == 1) P)hawH=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :$oiP  
} s *<T5Z  
O9)k)A]`O  
*9}~?#b  
Utility.log("Thread " + nThreadID + " is over!"); Ky'\t7p u  
bDownOver = true; 1)!]zV  
//nPos = fileAccessI.write (b,0,nRead); GoG_4:^#h  
} $I90KQB\_  
catch(Exception e){e.printStackTrace ();} A|P `\_  
} b'4r5@GO  
} Td![Id  
20mZ{_%  
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//打印回应的头信息 Ji:0J},m  
public void logResponseHead(HttpURLConnection con) }/Y)^  
{ 8?k.4{?  
for(int i=1;;i++) B4;P)\2  
{ 5>M@ F0  
String header=con.getHeaderFieldKey(i); < nyk:
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if(header!=null) OY(znVHU  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K.\-  
Utility.log(header+" : "+con.getHeaderField(header)); -
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else SP5t=#M6  
break; u5dyhx7  
} \EEU G^T  
} ~8G cWy6  
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|n.ydyu`  
public void splitterStop() |b)N;t  
{ O;<YLS^|6  
bStop = true; ,5Tw
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} DZ0\pp?S  
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} ki|w?0s  
7)au#K6  
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/* c)=UX_S!  
**FileAccess.java [KwwhI@3  
*//文件访问(定位，写) QjwCY=PK!  
package NetFox; {m<!-B95  
import java.io.*; @GE:<'_:{  
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public class FileAccessI implements Serializable{ Nh\y@\F>  
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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 MFLw^10(T  
RandomAccessFile oSavedFile; w'Q2Czso  
long nPos; sR*JU%  
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public FileAccessI() throws IOException f*~z|  
{ dCM*4B<  
this("",0); F`YxH*tO7  
} Z'z~40Bda  
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public FileAccessI(String sName,long nPos) throws IOException VR0#"  
{ quw:4W>  
oSavedFile = new RandomAccessFile(sName,"rw"); Li\BRlebR{  
this.nPos = nPos; 1_.#'U>  
oSavedFile.seek(nPos); MOW {g\{\  
} wH[}@w  
- dt<w;>W  
jj 9eFB  
public synchronized int write(byte[] b,int nStart,int nLen) "t"&6\  
{ >zAI#N4  
int n = -1; k|T0Bly3P  
try{ kXbdR  
oSavedFile.write(b,nStart,nLen); 7%4@*  
n = nLen; 1 +'HKT}  
} bwAL:  
catch(IOException e) & A<Pf.Us  
{ ;F<)BEXC<  
e.printStackTrace (); h8_~ OX  
} ' ! ls"qo  
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return n; in6iJ*E@'  
} L)ry!BuHI  
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} D`^9 u K  
?
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d\ Z#XzI8  
/* &Wup 7  
**SiteInfoBean.java ZVek`C
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*/ dO[w3\~  
package NetFox; lC i_G3C  
oFRb+H(E  
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public class SiteInfoBean { ~ Qt$)  
~:srm#IX  
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private String sSiteURL; //Site's URL {L8(5  
private String sFilePath; //Saved File's Path vv,(ta@t2  
private String sFileName; //Saved File's Name $'Hg}|53  
private int nSplitter; //Count of Splited Downloading File TGz5t$]I  
?iBHJ{  
2v<[XNX  
public SiteInfoBean() b#C"rTw  
{//nSplitter的缺省值为5 4&/-xg87(  
//default value of nSplitter is 5 t%AW0#TZ  
this("","","",5); %j=,c{`Q  
} 7>m#Y'ppl@  
9b
T,=b;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?Y~>H2  
{ "zO+!h'o  
sSiteURL= sURL; i4"xvLK4  
sFilePath = sPath; FBPT@`~v  
sFileName = sName; |JL47FR  
this.nSplitter = nSpiltter; ]eq3cwR[|  
\0pJ+@\T9  
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} P + nT%  
mYk5f_}  
4>^ %_Xj[  
public String getSSiteURL() 2g^Kf,m  
{ E}qeh"sJt  
return sSiteURL; pz^"~0o5  
} mHox  
d}',Bl+u{$  
/=\__$l)  
public void setSSiteURL(String value) !+H=e>Y6  
{ +-#| M|a  
sSiteURL = value; }h>e=<  
} w|PZSOJ  
4f"a
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]IJ.}  
public String getSFilePath() b,G+=&6u  
{ Bd"7F{H  
return sFilePath; FO}4~_
W{  
} D@Fa~O$75  
k 9Kv  
*.EtdcRo[  
public void setSFilePath(String value) i\rI j0+  
{ @Cm"lv.hz  
sFilePath = value; 9#6ilF:F  
} U'.>wjO  
fp4d?3G  
v(4C?vxhG  
public String getSFileName() ( L RX  
{ K"b vUH  
return sFileName; Hv0sl+  
} p9_45u`u2  
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public void setSFileName(String value) k=bv!T_o  
{ n*iaNaU"'  
sFileName = value; M7,|+W/RK  
} sS(^7GARa  
=GM!M@~,Ab  
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public int getNSplitter() xYt{=  
{ 
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return nSplitter; YQX>)'  
} D?5W1m]E,s  
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P!YT{}  
public void setNSplitter(int nCount) w6Tb<ja  
{ ieS
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nSplitter = nCount; q}BQu@'H  
} ~w[zX4@  
} ^Z:x poz,  
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A7_*zR@  
/* ,%nmCetD@  
**Utility.java ~P6K)V|@<  
*/ L1C'V/g  
package NetFox; /'VCJjzZ
 
ocgbBE  
~T4=Id  
public class Utility { Z/x<U.B  
JG}U,{7(  
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public Utility() {/0,lic  
{ vW)GUAF[  
p6}
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*%)L?*  
} ,}FYY66K  
NKd@Kp`,  
//线程睡眠 7 cIVK}&  
public static void sleep(int nSecond) ={L:q8v)  
{ ,CM$A}7[  
try{ Tu/JhP/g,`  
Thread.sleep(nSecond); B~PF<8h5  
} "F[VqqD  
catch(Exception e) l1W5pmhK]'  
{ m_Fw;s/9  
e.printStackTrace (); 6o1.?t?  
} QdW%5lM+  
} bNaJ{Dm$R  
@MB;Ez v  
//日志 >9u6@  
public static void log(String sMsg) 5E!|-xD  
{ Ugdm"  
System.err.println(sMsg); ~C!vfPC  
} B|GJboQ  
Fsq S)  
HZK0Ldf  
public static void log(int sMsg) ]-PF?8  
{ h0^V!.-5  
System.err.println(sMsg); caj)  
} G0]n4"~+?  
} 10}Zoq|)n  
zw5~|<  
Le3S;SY&  
/* Aoo'i  
**TestMethod.java v\MH;DW^Z  
*/ )E[5lD61  
package NetFox; n3|~X/I  
ZXUe4@qfl  
dl":?D4H  
public class TestMethod { 'g=yJ  
RD_;us@&&*  
-dvDAs{X  
public TestMethod() `jZX(H  
{ ///xx/weblogic60b2_win.exe dIpt&nH&$  
try{ 'Vrev8D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /e7'5#v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =AKW(v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); q/B+F%QiMQ  
fileFetch.start(); +pcj8K%  
} HRb_ZJz  
catch(Exception e){e.printStackTrace ();} Txfb-f!mv\  
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} SY$%!! @R  
(%P* rl  
f<}!A$wd  
public static void main(String[] args) n]$vCP  
{ 5AjK7[<L  
new TestMethod(); |@@mq!>-  
} Wig0OZj  
} C3b'Q  
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