http断点续传简单实现（java)

/* ]mi\Y"RO  
**SiteFileFetch.java uH?4d!G  
*/ w2
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package NetFox; 6iXV  
import java.io.*; cUP1Uolvn  
import java.net.*; nC !NZ  
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public class SiteFileFetch extends Thread { A@?-
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SiteInfoBean siteInfoBean = null; //文件信息Bean 9=6BQ`u  
long[] nStartPos; //开始位置 v!DK.PZbi  
long[] nEndPos; //结束位置 Pzd!"Gl9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |:4W5>sfg  
long nFileLength; //文件长度 "[k>pzl6  
boolean bFirst = true; //是否第一次取文件 6:8Nz   
boolean bStop = false; //停止标志 t~dK\>L  
File tmpFile; //文件下载的临时信息 55TFBDc  
DataOutputStream output; //输出到文件的输出流 LttA8hf5q?  
6Y6t.j0vN.  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） K$GQc"  
public SiteFileFetch(SiteInfoBean bean) throws IOException |H,WFw1%}  
{ Q(Q?L5  
siteInfoBean = bean; \(=xc2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6vTnm4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *kZH~]  
if(tmpFile.exists ()) k^ fW/  
{ IY[qWs  
bFirst = false; N}[!QE  
read_nPos(); |{-?OOKj  
} o(> #}[N}  
else m+7%]$  
{ =zrfh-lwH  
nStartPos = new long[bean.getNSplitter()]; +\dKe[j{g  
nEndPos = new long[bean.getNSplitter()]; F4"bMN  
} @].!}tz  
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} )K::WqR%w)  
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public void run() s:_j,/H0A}  
{ iqB%sIP  
//获得文件长度 (M u;U!M"P  
//分割文件 ,CPAS}kS  
//实例FileSplitterFetch 91yYR*  
//启动FileSplitterFetch线程 bUM4^m  
//等待子线程返回 :yi} CM4  
try{ I1s= =  
if(bFirst) c05-1  
{ yt,Ky8y1  
nFileLength = getFileSize(); Tj!\SbnA[  
if(nFileLength == -1) 5! +{JTXa  
{ 7B5b +  
System.err.println("File Length is not known!"); +O8zVWr  
} <-G3Qgm  
else if(nFileLength == -2) Z!fbc#L6  
{ r|
\""  
System.err.println("File is not access!"); ]mNsG0r6  
} `(P71T  
else 5.oY$tb(  
{ TXV^f*  
for(int i=0;i<nStartPos.length;i++) `)KGajB  
{ )Spa F)N8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9B83HV4J  
} XN?my@_HpM  
for(int i=0;i<nEndPos.length-1;i++) BNb_i H  
{ P\{s C6E  
nEndPos = nStartPos[i+1]; FjiIB1 T  
} 7i02M~*uS  
nEndPos[nEndPos.length-1] = nFileLength; ]:T:cO0_n  
} t,0}}9%?  
} vflC{,{=k>  
{-]K!tWda  
Y$)y:.2#  
//启动子线程 e}7!A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ePaC8sd0
  
for(int i=0;i<nStartPos.length;i++) 0jxXUWO  
{ >XRf= :3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u}_
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I3sf
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nStartPos,nEndPos,i); YD9vWk\/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ad3TD L?  
fileSplitterFetch.start(); ]]}iSw'  
} 7 TM-uA$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K$:btWSm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `qCL&(`%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4@mJEi{  
nEndPos = " + nFileLength); ^u0y<kItX  
// fileSplitterFetch[nPos.length-1].start(); 6L Fhhl^  
`jhbKgR[  
o"P)(;  
//等待子线程结束 U
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//int count = 0; J_|%8N{[x  
//是否结束while循环 *&h]PhY  
boolean breakWhile = false; /S^>06{-+  
8 K)GH:a  
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while(!bStop) pj3H4yCM:  
{ yw7bIcs|#b  
write_nPos(); /1.Z=@7  
Utility.sleep(500); S?D]P'<  
breakWhile = true; P+_1*lOG  

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for(int i=0;i<nStartPos.length;i++) R@>^t4#_Q0  
{ GlJOb|WOX  
if(!fileSplitterFetch.bDownOver) 5*90t{#  
{  zNn  
breakWhile = false; P~x4h{~Gd  
break; UxMei  
} Hxc>?  
} 9>&p:+D  
if(breakWhile) 8W7ET@`  
break;
7[R`52pP  
fti0Tz'  
~Xr[d07bC  
//count++; Ia{t/IX\[  
//if(count>4) 20Jlf?  
// siteStop(); {D,- Whi  
} 8LuU2Lo  
m>!o Yy_  
a%an={  
System.err.println("文件下载结束！"); 1NrNTBI@  
} ir|L@Jj,  
catch(Exception e){e.printStackTrace ();} D&],.N  
} p"*xyex  
P.^*K:5@  
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//获得文件长度 sYk#XNH  
public long getFileSize() <<@F{B7h  
{ .+lx}#-#  
int nFileLength = -1; &*Kk> 4  
try{ nVP|
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URL url = new URL(siteInfoBean.getSSiteURL()); ]\ZmK0q<:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,WoV)L'?  
httpConnection.setRequestProperty("User-Agent","NetFox"); %h
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<Y;w I#C  
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int responseCode=httpConnection.getResponseCode(); mMCd  
if(responseCode>=400) @j(2tJ,w  
{ dtV7YPz4+  
processErrorCode(responseCode); lXVh`+X/l  
return -2; //-2 represent access is error 52'6wwv6?  
} 7WNUHLEt  
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String sHeader; "5\6`\/
 
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for(int i=1;;i++) t7e7q"+/  
{ %T}*DC$&S  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +7y#c20  
//Utility.log(in.readLine()); |2jA4C2L}  
sHeader=httpConnection.getHeaderFieldKey(i); O6\c1ha  
if(sHeader!=null) ]KUeSg|  
{ vI"BNC*Q1  
if(sHeader.equals("Content-Length")) #aE>-81SS&  
{ TCkMJs?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); gBXoEn]
 
break; iBY16_q  
} .kfx\,lgm  
} Y7')~C`up^  
else /%bnG(4  
break; aR)w~s\6  
} '*G8;91u  
} m mH xPd  
catch(IOException e){e.printStackTrace ();} |Rm_8n%m  
catch(Exception e){e.printStackTrace ();} /:C<{m.[}  
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Utility.log(nFileLength); L=I;0Ip9y  
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return nFileLength; sH%Ts@Pl  
} =tGRy@QV'\  
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4)p ID`  
//保存下载信息（文件指针位置） vPrlRG6  
private void write_nPos() Ieh<|O,-C  
{ xO4""/
n  
try{ \0FwxsL  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Io{BO.K*Y  
output.writeInt(nStartPos.length); MieO1l  
for(int i=0;i<nStartPos.length;i++) m;ju@5X  
{ 5inCAPXz  
// output.writeLong(nPos); +DE;aGQ.z?  
output.writeLong(fileSplitterFetch.nStartPos); R%`fd *g  
output.writeLong(fileSplitterFetch.nEndPos); 60WlC0Y~u  
} ^AoX|R[1%  
output.close(); [i_evsUj?  
} `w)yR>lqh  
catch(IOException e){e.printStackTrace ();} >1` '5A}s  
catch(Exception e){e.printStackTrace ();} CXTtN9N9  
} =JxEM7r  
&%u m#XE  
l9&L$,=  
//读取保存的下载信息（文件指针位置） 3jHE,5m  
private void read_nPos() ~6+>2|wIS  
{ % pAbk
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try{ }[(v(1j='~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .0MY$0s  
int nCount = input.readInt(); f*VXg[&\\F  
nStartPos = new long[nCount]; v4Kf{
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nEndPos = new long[nCount]; 0-/@-qV\  
for(int i=0;i<nStartPos.length;i++) VHvL:z  
{ ,V{Bpr  
nStartPos = input.readLong(); Nv3u)?A3w  
nEndPos = input.readLong();
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} ant2];0p  
input.close(); r~2q`l'>  
} \ rKUPI\  
catch(IOException e){e.printStackTrace ();} ]@}o"Td  
catch(Exception e){e.printStackTrace ();} G"".;}AV  
} KEf1GU6s  
3_]QtP3  
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private void processErrorCode(int nErrorCode) n(CM)(ozU  
{ U~dqxR"Q  
System.err.println("Error Code : " + nErrorCode); ZvK.X*~s  
} LLbI}:  
!_W']Crb]]  
nGur2}>n  
//停止文件下载 $x#
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public void siteStop()  `YO&  
{ [w)KNl  
bStop = true; :Y4Sdj  
for(int i=0;i<nStartPos.length;i++) VFm)!'=I  
fileSplitterFetch.splitterStop(); BgY|v [M&  
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} LLMGs: [  
} ;ULw-&]P  
//负责部分文件的抓取 -lXQQ#V -  
**FileSplitterFetch.java _,I~1"  
*/ IoV"t
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package NetFox; n8D'fvY  
f lt'~fe  
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import java.io.*; ZT`" {#L  
import java.net.*; =`Ky N/  
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public class FileSplitterFetch extends Thread { kV3LFPf>0  
?}EWfs
A  
n7zM;@{7  
String sURL; //File URL O"_QDl<ya  
long nStartPos; //File Snippet Start Position Z&h:3;  
long nEndPos; //File Snippet End Position R@`xS<`L/  
int nThreadID; //Thread's ID {}=5uU2Tu  
boolean bDownOver = false; //Downing is over =PnNett}a  
boolean bStop = false; //Stop identical ;6?,Yhk$h  
FileAccessI fileAccessI = null; //File Access interface >:0N)Pj  
)0Vj\>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tA9Ew{3s  
{ VP7LKfv  
this.sURL = sURL; f<R 3ND)  
this.nStartPos = nStart; 1k"i"kRM  
this.nEndPos = nEnd; 5bol)Z9BO  
nThreadID = id; w[G-=>;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 A}3E)Qo=G  
} '8I=Tn  
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public void run() "kucFf f  
{ j9cB<atL  
while(nStartPos < nEndPos && !bStop) FtWO[*#  
{ F'_z$,X6  
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j}8^gz]  
try{ 2"o<>d  
URL url = new URL(sURL); =sS=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5F:\U  
httpConnection.setRequestProperty("User-Agent","NetFox"); P+3 ]g{2w  
String sProperty = "bytes="+nStartPos+"-"; 9(bbV5}  
httpConnection.setRequestProperty("RANGE",sProperty); %H}M[_f  
Utility.log(sProperty); IY?o \vC  
kC'm |Y@T  
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InputStream input = httpConnection.getInputStream(); ~{6}SXp4U  
//logResponseHead(httpConnection); 9YBlMf`KEf  
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byte[] b = new byte[1024]; >PG
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int nRead; qz!^< M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 26j-1c!NGd  
{ ~Oi.bP<
,  
nStartPos += fileAccessI.write(b,0,nRead); $% W.=a'5  
//if(nThreadID == 1) >waA\C}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E/E|*6R  
} HaOSFltf#  
Q|g>ga-a  
>Q)S-4iR  
Utility.log("Thread " + nThreadID + " is over!"); a$LoQ<f_  
bDownOver = true; /EvT%h?p  
//nPos = fileAccessI.write (b,0,nRead); <(us(zbk]  
} vLCm,Bb2L  
catch(Exception e){e.printStackTrace ();} v/`#Gu^P  
} [bN_0T.YI  
} BkDq9>  
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|@)jS
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//打印回应的头信息 BU^E68?G  
public void logResponseHead(HttpURLConnection con) qmnW  
{ L_>LxF43  
for(int i=1;;i++) M!\6Fl{ b  
{ 1w>G8  
String header=con.getHeaderFieldKey(i); ?j} Fxr  
if(header!=null) QO|jdlg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); f:9qId ;/M  
Utility.log(header+" : "+con.getHeaderField(header)); G<t_=j/r  
else yIS&ZtBA  
break; c*)PS`]t  
} *0 ;|  
} {d,^tG}  
m9aP]I3g]\  
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public void splitterStop() Zb~G&. 2g  
{ 0-U%R)Q  
bStop = true; cLMFC1=b  
} W1UqvaR  
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w{Y:p[}  
} 1ka58_^  
mm
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/* <9?`zo$y  
**FileAccess.java *&W1|Qkg_  
*//文件访问(定位，写) 4&E&{<;  
package NetFox; |JCn=v@  
import java.io.*;
5U/C 0{6  
"ODs.m oq  
luO4ap]*  
public class FileAccessI implements Serializable{ w Yr M2X@  
HQ3kxOT  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7p,!<X}%  
RandomAccessFile oSavedFile; 1?T^jcny:M  
long nPos; P.]O8r  
M{U7yE6*j*  
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public FileAccessI() throws IOException J<7nOB}OD  
{ @*~cmf&FIQ  
this("",0); 7vK}aOs0  
} j;i7.B"[  
d##'0yg  
ILXVyU  
public FileAccessI(String sName,long nPos) throws IOException mybjcsV4  
{ :8Jn?E (36  
oSavedFile = new RandomAccessFile(sName,"rw"); jX{t/8v/s4  
this.nPos = nPos; 4[m4u6z=  
oSavedFile.seek(nPos); {K+]^M  
} 4 O~zkg  
z8n]6FDiE  
4krK CD>|G  
public synchronized int write(byte[] b,int nStart,int nLen) m=%WA5c?  
{ a`uHkRX )U  
int n = -1; Q::6|B,G  
try{ POc-`]6<F  
oSavedFile.write(b,nStart,nLen); \^rAH@  
n = nLen; iKuSk~  
} -!z,t7!  
catch(IOException e) ?3:xR_VWZu  
{ A!j6JY.w  
e.printStackTrace (); @-Js)zcl q  
} H0
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return n; 4zM$I  
} !|gln)
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} Iz<}>J B  
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/* X}$uvB}+>  
**SiteInfoBean.java bl;C=n  
*/ #(G#O1+  
package NetFox; &jHnM^nQ  
N\OeWjA F  
@< @\CiM  
public class SiteInfoBean { H,H=y},  
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private String sSiteURL; //Site's URL Z ^tF  
private String sFilePath; //Saved File's Path 
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private String sFileName; //Saved File's Name hDJ84$eVZ  
private int nSplitter; //Count of Splited Downloading File g&30@D"  
[9E<z2H  
CYZx/r
<  
public SiteInfoBean() \)pT+QxZ  
{//nSplitter的缺省值为5 qh)o44/ $  
//default value of nSplitter is 5
{-(B  
this("","","",5); 'bpx  
} MDCK@?\  
<-:gaA`KM  
HV^*_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }.x&}FqXE  
{ 0b0.xz\~U  
sSiteURL= sURL; #lM :BO  
sFilePath = sPath; :b&O{>M]Y  
sFileName = sName; bF'^eR  
this.nSplitter = nSpiltter; .O
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i-'rS/R  
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} R30{/KK  
{U&*8Q(/  
=Zcbfo_&  
public String getSSiteURL() RSLMO8  
{ $~<);dYu0  
return sSiteURL; YH( 54R  
} {BBL`tg60  
6^pddGIG  
G(-1"7  
public void setSSiteURL(String value) h^h!OQKQ  
{ k{3:$, b  
sSiteURL = value; ^h z4IZ^  
} lZ5 lmsCU  
]:B|_|H  
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public String getSFilePath() Q Fv"!Ql  
{ ^d!(8vh  
return sFilePath; _h4{Sx  
} `Trpv$  
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g|r:+%,M  
public void setSFilePath(String value) $0C1';=^}  
{ f)p c$~B  
sFilePath = value; 0s"g%gq|  
} MXWCYi  
_u$X.5Q;  
}VlX!/42  
public String getSFileName() d7+YCi?  
{ \Lxsg!wtJ  
return sFileName; %a;N)1/  
} #WD}XOA  
LHjGlBy  
u:r'&#jb~@  
public void setSFileName(String value) *xxG@h|5n  
{ <QGf9{m  
sFileName = value; XOQj?Q7)U  
} -AUdBG  
6$qn'K$  
#M;Cw}pW  
public int getNSplitter() J>(I"K%  
{ <4,n6$E  
return nSplitter; :jB8Q$s  
} 9ZjSM,+  
U$R+&@;  
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public void setNSplitter(int nCount) l$$N~FN  
{ @#q>(Ox%  
nSplitter = nCount; [ay~l%x  
} ", b}-B  
} ZOGH.`  
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ngM>Tzirt  
/* qrBo'@7  
**Utility.java CN6@g^)P  
*/ {64od0:T  
package NetFox; trL:qD+{(  
@N?A0S/  
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public class Utility { 5#+G7 'k  
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public Utility() gR)T(%W  
{ ydOJ^Yty  
vy?Zz<c;  
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} @l~zn%!X  
8KKI.i8`  
//线程睡眠 b]s.h8+v;  
public static void sleep(int nSecond) @Y":DHF5q  
{ epa)~/sA  
try{ <%fcs"Mb  
Thread.sleep(nSecond); o@6:|X)7  
} / $7E  
catch(Exception e) q~9Y&>D  
{ Y#Pl)sRr  
e.printStackTrace (); x}I'
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} [5$=G@ zf  
} {Rb|";  
\Ub=Wm\
 
//日志 5!Y51R^c  
public static void log(String sMsg) KTX;x2r  
{ R1Jj 3k  
System.err.println(sMsg); ,zmGKn#n2  
} h^#K4/  
yM(zc/?  
S~auwY,<  
public static void log(int sMsg) X!r9  
{ FFGG6r  
System.err.println(sMsg); L=zt\L  
} ^M60#gJ  
} %,Fx qw  
wmu#@Hf/[h  
wIT0A-Por4  
/* 6X{RcX]/  
**TestMethod.java |`d5Y#26  
*/ @m14x}H  
package NetFox; i6F`KF'i&  
,1+AfI  
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public class TestMethod { lqPzDdC^>  
'Dl31w%:  
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public TestMethod() RM2<%$  
{ ///xx/weblogic60b2_win.exe +/,
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try{ r
|[uR$|Y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P)he3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0_7A <   
SiteFileFetch fileFetch = new SiteFileFetch(bean); fv?vO2
nj  
fileFetch.start(); (dl7+  
} J)R;NYl  
catch(Exception e){e.printStackTrace ();} -A}U^-'a}  
$ K>.|\
 
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} *^]Hqf(`  
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public static void main(String[] args) ;E? Z<3{  
{ jr$
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new TestMethod(); ]+RBykr  
} \%fl`+`  
} =<nx[J  
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