http断点续传简单实现（java)

/* kWF4k  
**SiteFileFetch.java 2xZg, \  
*/ !aeL*`;  
package NetFox; 7$z")JB  
import java.io.*; V,<,;d fR  
import java.net.*; &vj+3<2  
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public class SiteFileFetch extends Thread { qRJg/~_h{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean '/\@Mc4T  
long[] nStartPos; //开始位置 FZ #ngrT  
long[] nEndPos; //结束位置 WVftLIJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 r[eZV"  
long nFileLength; //文件长度 k*-_CO-h  
boolean bFirst = true; //是否第一次取文件 D=mU!rjr1  
boolean bStop = false; //停止标志 Lbq"( b  
File tmpFile; //文件下载的临时信息 _0)#-L>xKF  
DataOutputStream output; //输出到文件的输出流 X9/V;!  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） i`gsT[JQRX  
public SiteFileFetch(SiteInfoBean bean) throws IOException .lb2`!'r&  
{ f/Grem  
siteInfoBean = bean; NO +j   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Uey.@2Q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); UY5ia4_D  
if(tmpFile.exists ()) @@*->  
{ fg8V6FS  
bFirst = false; 6^wg'u]c  
read_nPos(); la8se=^  
} Vvm6T@b M8  
else b*nytF  
{ _R1
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nStartPos = new long[bean.getNSplitter()]; t+qLQY}=  
nEndPos = new long[bean.getNSplitter()]; J@"Pv~R  
} }kT;UdIu;  
%{yr#F=t#]  
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} -]Z!_[MlDF  
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public void run() DOkEWqM!  
{ .Ap[C? mV  
//获得文件长度 itm;,Sbg  
//分割文件 .'lc[iI9)d  
//实例FileSplitterFetch ( ]AErz+  
//启动FileSplitterFetch线程 ]RPv@z:V  
//等待子线程返回 !__f  
try{ Umv_{n`  
if(bFirst) ;G0~f9  
{ %;yo\  
nFileLength = getFileSize(); b/"gkFe#  
if(nFileLength == -1) kmy?`P10(z  
{ GL@s~_;T6  
System.err.println("File Length is not known!"); 0+/L?J3  
} C0 .Xp  
else if(nFileLength == -2) q .tVNKy%  
{ w6Dysg:  
System.err.println("File is not access!"); (dpBGt@  
} L0UAS'hf  
else -njxc{b  
{ vO]gj/SaT  
for(int i=0;i<nStartPos.length;i++) R{#-IH="  
{ UldKlQ8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Kw(/#C:$  
} S?r:=GS  
for(int i=0;i<nEndPos.length-1;i++) ]}ff*W  
{ b=F"  
nEndPos = nStartPos[i+1]; A!Ng@r  
} vD:.1,72  
nEndPos[nEndPos.length-1] = nFileLength; YCh!D dy  
} 9`{Mq9J  
} WN>.+qM~8  
(Uv{%q.n6  
0w< iz;30  
//启动子线程 tOnaD]J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :lgIu .  
for(int i=0;i<nStartPos.length;i++) ^P"
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{ a+A/
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BR*""/3`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), eP&K]#  
nStartPos,nEndPos,i); ;y=w :r\A  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Oq*a4_R'YV  
fileSplitterFetch.start(); 5Lum$C c}  
} *%B%BJnX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), { zlq6z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^nkwT~Bya  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &|9mM=^  
nEndPos = " + nFileLength); r\@"({q}_-  
// fileSplitterFetch[nPos.length-1].start(); /W:}p(>4a  
PM9HfQU?  
6@H&S  
//等待子线程结束 |8`}yRsQ  
//int count = 0; [DGq{(
O  
//是否结束while循环 A"vI6ud>  
boolean breakWhile = false; zFP}=K:o)  
TCmWn$LeE  
N%y%)MI8  
while(!bStop) Sl:\5]'yJ  
{ -/#3U{O  
write_nPos(); b'3#FI=:  
Utility.sleep(500); MMhd-B1O&  
breakWhile = true; $N,9e  
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for(int i=0;i<nStartPos.length;i++) f,t[`0 va  
{ ut3jIZ1]  
if(!fileSplitterFetch.bDownOver) &_q;X;}  
{ um&N|5lHb  
breakWhile = false; 5mER&SX  
break; Rv.W~FE^  
} Ko/_w_  
} O-|RPW}  
if(breakWhile) CdWGb[uI  
break; qaw5<
 
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//count++; "Hgn2o.;5  
//if(count>4) "q#(}1Zd  
// siteStop(); Bfi9%:eG  
} KC}B\~ +  
~+CNED0z+  
8f8+3  
System.err.println("文件下载结束！"); @3VL _g:  
} =%2 E|/  
catch(Exception e){e.printStackTrace ();} [jAhw>  
} cv#H  
JN|<R%hy  
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//获得文件长度 g](m& O  
public long getFileSize() '\_ic=&u  
{ 2"BlV*\lS  
int nFileLength = -1; yv$MQ~]  
try{ Hsp|<;Yg  
URL url = new URL(siteInfoBean.getSSiteURL()); Qf=%%5+?8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wz=ZhE9g  
httpConnection.setRequestProperty("User-Agent","NetFox"); 35&&*$Jm  
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int responseCode=httpConnection.getResponseCode(); t{?_]2vl  
if(responseCode>=400) n>#h(  
{ +|#:*GZ  
processErrorCode(responseCode); }d6g{`  
return -2; //-2 represent access is error +XY}-  
} s-8>AW ep  
>vP^l {SD  
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String sHeader; b[*di{?-  
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for(int i=1;;i++) F},JP'\X  
{ RKjA`cJ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @XmMD6{<  
//Utility.log(in.readLine()); 78 UT]<Q;K  
sHeader=httpConnection.getHeaderFieldKey(i); J~c]9t  
if(sHeader!=null) <D&75C#  
{ Q{$2D&  
if(sHeader.equals("Content-Length")) )dlt$VX  
{ f5sk,Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (8H^{2K~  
break; L G=Q  
} F$+_Z~yt3;  
}
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else jkD5Z`D  
break; -Tz9J4xU&  
} ja9y  
} E)Hp.  
catch(IOException e){e.printStackTrace ();} &JF^a  
catch(Exception e){e.printStackTrace ();} u$a%{46  
]?<uf40Mm  
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Utility.log(nFileLength); [q(7Jv  
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return nFileLength; bgEUG  
} PDGh\Y[AK,  
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-MOf[f^  
//保存下载信息（文件指针位置） ~Q6ufTGhpM  
private void write_nPos() C w$y  
{ K-#Rm%J+Wy  
try{ lI&0 V5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "` 9W"A=  
output.writeInt(nStartPos.length); xvrCm`3n@  
for(int i=0;i<nStartPos.length;i++)  ;xry  
{ ^l iyWl  
// output.writeLong(nPos); OSq"q-Q  
output.writeLong(fileSplitterFetch.nStartPos); l'o'q7&=z  
output.writeLong(fileSplitterFetch.nEndPos); gbSZ- ej  
} wk-ziw  
output.close(); H"n"Q:Yp  
} E%40u.0  
catch(IOException e){e.printStackTrace ();} {v2Q7ZO-  
catch(Exception e){e.printStackTrace ();} sRYFu%  
} K}a[~  
l(<o,Uv[`  
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//读取保存的下载信息（文件指针位置） dc:|)bK M  
private void read_nPos() 8{h:z 9]J  
{ ]54V9l:  
try{ `Th!bk  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 98V9AOgk  
int nCount = input.readInt(); %q:V  
nStartPos = new long[nCount]; ? ZN8Ku  
nEndPos = new long[nCount]; J6f;dF^  
for(int i=0;i<nStartPos.length;i++) }l_) d  
{ i[FBll-  
nStartPos = input.readLong(); \y<n{"a  
nEndPos = input.readLong(); G>H&M#7K  
} .@xwl}o$OL  
input.close(); Zcf?4{Kd?  
} #X|'RL($  
catch(IOException e){e.printStackTrace ();} H!s &]b  
catch(Exception e){e.printStackTrace ();} 1Z*-@%RX  
} OcIJT1  
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private void processErrorCode(int nErrorCode) }_Jai4O  
{ {)-%u8J\`N  
System.err.println("Error Code : " + nErrorCode); Q6DE|qnV  
} LM<OYRB(  
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%n{E/06f  
//停止文件下载 P$w0.XZa  
public void siteStop() 7';PI!$  
{ JLs7[W)O  
bStop = true; OyTBgS G?a  
for(int i=0;i<nStartPos.length;i++) z3>}(+  
fileSplitterFetch.splitterStop(); kgYa0 e5  
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2MJ0[9  
} J *^|ojX  
} ]D<r5P%  
//负责部分文件的抓取 x{IOn;>R  
**FileSplitterFetch.java /G</ [N5  
*/ whRc YnJ  
package NetFox; |\elM[G"g  
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import java.io.*; x?f3XEA_  
import java.net.*; R$cg\DD  
{n|Ra[9_  
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public class FileSplitterFetch extends Thread { 'w!Hjq]$  
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+ PGfQN  
String sURL; //File URL lE%0ifu  
long nStartPos; //File Snippet Start Position 22(0Jb\_  
long nEndPos; //File Snippet End Position \{abyi;  
int nThreadID; //Thread's ID 2<|+h= &  
boolean bDownOver = false; //Downing is over du`],/ 6  
boolean bStop = false; //Stop identical d}IVYI  
FileAccessI fileAccessI = null; //File Access interface gK`6NUj  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u:"mq.Q  
{ 8 =J6{{E  
this.sURL = sURL; b9`MUkGG
d  
this.nStartPos = nStart; /Nb&e  
this.nEndPos = nEnd; gdHPi;  
nThreadID = id; HR)joD*q;[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;h] zN  
} F) < f8F  
=V%s^  
.:$%3#N$(Y  
public void run() }1Q]C
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{ &Zq43~  
while(nStartPos < nEndPos && !bStop) I gA0RY1  
{ 2&06Db(  
:
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+9,"ne1'e  
try{ 0
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URL url = new URL(sURL); mu|#(u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G#n27y nh  
httpConnection.setRequestProperty("User-Agent","NetFox"); Bd)Qz(>rw  
String sProperty = "bytes="+nStartPos+"-"; ?%B%[u  
httpConnection.setRequestProperty("RANGE",sProperty); ZZ?=^g  
Utility.log(sProperty); e9"<.:&  
d-39G*;1  
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InputStream input = httpConnection.getInputStream(); ^!N_Nx/M  
//logResponseHead(httpConnection); 6z!?U:bT  
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byte[] b = new byte[1024]; C$ nT&06o  
int nRead; F8>Fp"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) c,4UnEoCR  
{ EC&w9:R  
nStartPos += fileAccessI.write(b,0,nRead); uiM*!ge  
//if(nThreadID == 1) |cUlXg=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I
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} vlOMB  
(&+ ~hW5d  
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Utility.log("Thread " + nThreadID + " is over!"); IP/ zFbc  
bDownOver = true; CzST~*lH  
//nPos = fileAccessI.write (b,0,nRead); A)s  
} om9fg66  
catch(Exception e){e.printStackTrace ();} pH'#v]"  
} bU(t5 [
  
} W1Ur~x`  
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+'JM:};1X8  
//打印回应的头信息 ki=-0G*]  
public void logResponseHead(HttpURLConnection con) Tld%NE  
{ }4 5|  
for(int i=1;;i++) lLyMm8E%pZ  
{ r4A%`sk@  
String header=con.getHeaderFieldKey(i); 8%>  Ls  
if(header!=null) 7*~
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); w\8grEj  
Utility.log(header+" : "+con.getHeaderField(header)); Cf J@|Rh  
else xG\&QE  
break; *ZF7m_8u{  
} fQ'P2$  
} =H3 JRRS  
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={YW*1Xw  
public void splitterStop() 9Clddjf?c  
{ <eI7xifD  
bStop = true; UYD(++  
} Z?O aY4  
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Xc"S"a^\%  
} TY5<hPU=  
2?nK71c"  
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/* +#A>[,U  
**FileAccess.java j'#W)dp(  
*//文件访问(定位，写) _{TGO jZr  
package NetFox; G6]M~:<i  
import java.io.*; N9Y,%lQ|B8  
a UAPh  
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public class FileAccessI implements Serializable{ "Z#97Jc+J  
w91{''sK  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `BdZqXKG  
RandomAccessFile oSavedFile; mc~d4<$`!  
long nPos;
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public FileAccessI() throws IOException |j#x}8[(  
{ w%GEOIj}  
this("",0); +^1HtI|y  
} ~^w;`~L  
L'`W5B@  
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public FileAccessI(String sName,long nPos) throws IOException GG/~)^VMe  
{  # G0jMQ  
oSavedFile = new RandomAccessFile(sName,"rw"); ijw'7d|,  
this.nPos = nPos; 0jro0f'  
oSavedFile.seek(nPos); yOxJx7uD  
} ]}<wS]1  
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public synchronized int write(byte[] b,int nStart,int nLen) GX4# IRq  
{ e(@YBQ/Z  
int n = -1; ahU\(=  
try{ !6'j W!  
oSavedFile.write(b,nStart,nLen); OAEJ?ik  
n = nLen; 9e@Sx{?r  
} 9\0  
catch(IOException e) 6(f[<V!r  
{ MR:Co4(  
e.printStackTrace (); {()8 Wr  
} lGwX.cA!'  
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return n; k$9oUE,  
} \Se>u4~L  
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} 3gQQ,V..  
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/* -4mUGh1dy  
**SiteInfoBean.java ff**)Xdh  
*/ 7[[XNJP  
package NetFox; EX7gTf#  
-\:pbR
  
.Vj;[p8  
public class SiteInfoBean { 3+;]dqZ  
X<9jBj/t  
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private String sSiteURL; //Site's URL iEux`CcJ.  
private String sFilePath; //Saved File's Path =5a~xlBjD  
private String sFileName; //Saved File's Name U<|kA(5  
private int nSplitter; //Count of Splited Downloading File r5xu#%hgp;  
r]iec{ ^  
_'JKPD[  
public SiteInfoBean() Xhe25  
{//nSplitter的缺省值为5 MR=>DcR  
//default value of nSplitter is 5 zHw[`"[  
this("","","",5); #(FG
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} +e. bO5Y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o /AEp)8  
{ *IJctYJaX  
sSiteURL= sURL; <\
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sFilePath = sPath; Z#IRNFj  
sFileName = sName; 8 C@iD%  
this.nSplitter = nSpiltter; }A'QXtI/G  
)s4#)E
1  
h`F8GNx(  
} Gdq_T*  
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public String getSSiteURL() `{s:lf  
{ t5G@M&d4Eo  
return sSiteURL; ;>{B
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} V)V\M6  
c~[L;_  
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public void setSSiteURL(String value) ':lADUt  
{ MYFRrcu;  
sSiteURL = value; RR<92R  
} glbU\K> >  
_[zO?Div[  
@{\q1J>  
public String getSFilePath() 1Rc'2Y  
{ D|} y{~  
return sFilePath; X!V@jo9?  
} TXD\i Dq  
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6;i]v|M-  
public void setSFilePath(String value) 4<CHwIRHY  
{ %|bqL3)a_  
sFilePath = value; U@x5cw:  
} D'2&'7-sm\  
E#X(0(A)  
z@iu$DZ  
public String getSFileName() A6YkoYgC  
{ q|0Lu  
return sFileName; 2uu"0Rm%  
} %:yJ/&-Q,Z  
(Vnv"= (  
^noKk6Aaa  
public void setSFileName(String value) #Y`GWT1==  
{ Ytop=ZIl'  
sFileName = value; | z=:D*uh~  
} vzA)pB~;  
Dp4\rp
s  
xhLVLXZ9  
public int getNSplitter() ]p~w`_3v  
{ i7v> 9p7  
return nSplitter; Z;`ts/?SY]  
} {{w5F2b((%  
c,-3+b  
oMk6ZzZ,>  
public void setNSplitter(int nCount) cL}}^  
{ sw A^oU  
nSplitter = nCount; #m[R1G#  
} s>hNw
b/  
} 5jAiqJq~y:  
q9 !)YP+w  
<=2\xJfxB  
/* .BP@1K  
**Utility.java .&fG_(6|  
*/ ErmlM#u  
package NetFox; ;zk& 7P0  
=E?kxf[X  
~~,] b  
public class Utility { ObJgJr  
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public Utility() ;>YLL}]j  
{ @$o.Z;83`r  
&/o4R:i  
fg"]4&`j-  
} +P YX.  
mcbvB5U  
//线程睡眠 =GH>-*qp  
public static void sleep(int nSecond) SStaS<q'  
{ }t5-%&gBY0  
try{ ?}p~8{ '  
Thread.sleep(nSecond); .yK~FzLs  
} R]L$Ld< ij  
catch(Exception e) = cQK^$6(  
{ uW4)DT9[5  
e.printStackTrace (); ,i0Dw"/u  
} PX!$
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} gt]
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ZbBz@1O  
//日志 y~eQVnH5W  
public static void log(String sMsg) &!Sq6<!v2  
{ W&MZ5t,k=  
System.err.println(sMsg); BJA&{DMHm  
} [{R^!Az&b<  
*nZe|)m  
Wgp}v93  
public static void log(int sMsg) ?w/i;pp<,  
{ V\Q=EsHj   
System.err.println(sMsg); CYkU-  
} B8J_^kd  
} 7T7 A\  
l=+hs  
aYy+iP'$  
/* 5pC+*n.  
**TestMethod.java pf&H !-M  
*/ 8/i];/,v*M  
package NetFox; )-jA4!&  
>oD,wSYV~  
10gh4,z[  
public class TestMethod { D5Z@6RVt  
<I 5F@pe'  
w; rQ\gj  
public TestMethod() U!y GZEU"[  
{ ///xx/weblogic60b2_win.exe ;,WI_iP(w  
try{ O%Hc%EfG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %?sPKOh3N}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q7#4e?1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ./7*<W:  
fileFetch.start(); m[>pv1o  
} s:O8dL /  
catch(Exception e){e.printStackTrace ();} 4DwQ7KX  
0pfgE=9  
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} Xh5&J9pw   
EOj.Jrs~  
v.Vdjs  
public static void main(String[] args) . .5s2  
{ s*;rt  
new TestMethod(); Z=KHsMnB  
} \86:f<)P  
} 2h;#BJ))  
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