http断点续传简单实现（java)

/* aHu0z:  
**SiteFileFetch.java 3.#L  
*/ [;IEZ/ZX  
package NetFox; L&s~j/pR  
import java.io.*; {1Cnrjw  
import java.net.*; 75p9_)>96  
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public class SiteFileFetch extends Thread { @&m]:GR  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ,N:^4A  
long[] nStartPos; //开始位置 8hS^8  
long[] nEndPos; //结束位置 J \|~k2~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 K
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long nFileLength; //文件长度 8tSY|ME  
boolean bFirst = true; //是否第一次取文件 y _apT<P  
boolean bStop = false; //停止标志 r=3`Eb"t  
File tmpFile; //文件下载的临时信息 iJhieNn  
DataOutputStream output; //输出到文件的输出流 e eN`T&cI  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） N KgEs  
public SiteFileFetch(SiteInfoBean bean) throws IOException kM4z %  
{ e@VJ-s  
siteInfoBean = bean; X=-=z5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2~/`L=L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); XdDQ$'*X  
if(tmpFile.exists ()) SujEF`"  
{ VtzZ1/JE  
bFirst = false; &TRKd)wd  
read_nPos(); pD[&,gV$  
} ~SBW`=aP}  
else 9;XbyA]  
{ :I7qw0?  
nStartPos = new long[bean.getNSplitter()]; $:5h5Y#z  
nEndPos = new long[bean.getNSplitter()]; zUJXA:L9  
} KO8vUR*2R  
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} )G/
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public void run() <H]PP6_g:  
{ ;DX{+Z[  
//获得文件长度 Q(N'Oj:J  
//分割文件 0_je@p+$  
//实例FileSplitterFetch ynra%"sd  
//启动FileSplitterFetch线程 "UD)3_R  
//等待子线程返回 0y<9JvN$9  
try{ 9Oj b~  
if(bFirst) ,9
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{ [wSoZBl  
nFileLength = getFileSize(); Mfz(%F|<  
if(nFileLength == -1) o7+<sL  
{ bS:$VyH6  
System.err.println("File Length is not known!"); GB `n  
} } -4p8Zt  
else if(nFileLength == -2) z|AknEE,  
{ &/uakkS  
System.err.println("File is not access!"); U[;ECw@  
} "K>!+<  
else cv_O2Q4,@  
{ ZMyd+C_P2  
for(int i=0;i<nStartPos.length;i++) *qMjoP,  
{ c$A}mL_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )Knsy  
} jq/{

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for(int i=0;i<nEndPos.length-1;i++) < R@&<E6  
{ &:+_{nc,  
nEndPos = nStartPos[i+1]; rUiUv(q  
} mOjl0n[To]  
nEndPos[nEndPos.length-1] = nFileLength; mW_A3S5  
} ~}~ yR*K%  
} Xw^:<Nx:  
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d<;XQ.Wo7  
//启动子线程 6d 8n1_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1 gRR  
for(int i=0;i<nStartPos.length;i++) ~0.@1zEXj  
{ ',RR*{I  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uqy~hY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), P|)SXR  
nStartPos,nEndPos,i); n_] OYG>U  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~Uz|sQ*G  
fileSplitterFetch.start(); naB[0I& N  
} q%^gG03.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }KkH7XksF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z<P#djx  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X4*/h$48 w  
nEndPos = " + nFileLength); 0P53dF  
// fileSplitterFetch[nPos.length-1].start(); |y=D^NTG  
}`^<ZNkb/  
IPE
(  
//等待子线程结束 X}bgRzj  
//int count = 0; kp;MNRc  
//是否结束while循环
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boolean breakWhile = false;
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while(!bStop) m :^,qC  
{ D{z=)'/F  
write_nPos(); en~(XE1  
Utility.sleep(500); )d1,}o  
breakWhile = true; KoXXNJax  
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for(int i=0;i<nStartPos.length;i++) \1B*iW  
{ ZmHl~MR@  
if(!fileSplitterFetch.bDownOver) 6<~y!\4;F  
{ >) :d38M  
breakWhile = false; U&a]gkr  
break; !c`1~a!  
} n*xNMw1x"T  
} 1-[{4{R  
if(breakWhile) hP#&]W3:  
break; hg>YOf&RG  
(6+0U1[Iz  
C]XD
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//count++; |3cR'|<Ual  
//if(count>4) =f p(hX"  
// siteStop(); WL~`L!_. A  
} :R&tO3_F  
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>) ^!gz8  
System.err.println("文件下载结束！"); Zn!SHj  
} TP^0`L  
catch(Exception e){e.printStackTrace ();} u!S{[7 FY  
} @'
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ouI0"R&@  
BW;u?1Xa  
//获得文件长度 7> QtO  
public long getFileSize() m4 (Fuu  
{ *dl@)~i  
int nFileLength = -1; J.d `tiN  
try{ / u{r5`4  
URL url = new URL(siteInfoBean.getSSiteURL()); %"6IAt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o_5@R
+&  
httpConnection.setRequestProperty("User-Agent","NetFox"); b6(yyYdF  
VQ;=-95P  
re*/JkDq3K  
int responseCode=httpConnection.getResponseCode(); '$VR_N\  
if(responseCode>=400) xl^'U/  
{ A.FI] K@  
processErrorCode(responseCode); ^
s*} 0
 
return -2; //-2 represent access is error HKwGaCj`  
} pf_ /jR  
V_kE"W)  
`4qKQJw  
String sHeader; ~83P09\T%  
#rwR)9iC0  
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for(int i=1;;i++) YB|9k)Z2[  
{ \zUsHK?L"t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); v=>Gvl3&U  
//Utility.log(in.readLine()); EUkNh
>U?  
sHeader=httpConnection.getHeaderFieldKey(i); /WfxI>v  
if(sHeader!=null) luT8>9X^:a  
{ gib]#n1!p  
if(sHeader.equals("Content-Length")) M=A9ax  
{ M)7enp) F.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); EoeEg,'~F  
break; ;GSJnV  
} @El<"\  
} :~R Fy?xRa  
else ^!_7L4&y  
break; Z3>3&|&  
} _)2TLA n3  
} >Eg.c  
catch(IOException e){e.printStackTrace ();} hpV /F  
catch(Exception e){e.printStackTrace ();} }A/&]1GWk  
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jYID44$  
Utility.log(nFileLength); yc=#Jn?S  
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return nFileLength; h_
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} W;]UP$5l  
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]V^.!=gh$  
//保存下载信息（文件指针位置） 6v O)s!b  
private void write_nPos() 6-14Htsk6  
{ 4Olv8nOe<  
try{ aw%v
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output = new DataOutputStream(new FileOutputStream(tmpFile)); )"jn{%/t  
output.writeInt(nStartPos.length); ]{+M>i[  
for(int i=0;i<nStartPos.length;i++) [k7N+W8  
{ fUKdC\WL  
// output.writeLong(nPos); LY:?OGh  
output.writeLong(fileSplitterFetch.nStartPos); ?mfWm{QTt  
output.writeLong(fileSplitterFetch.nEndPos); 8!Mzr1:  
} ,xe@G)a  
output.close(); %aE7id>v6  
} (`.qG &6p  
catch(IOException e){e.printStackTrace ();} G:C6`uiy`  
catch(Exception e){e.printStackTrace ();} <;0N@  
} um2s^G  
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q=% C (  
//读取保存的下载信息（文件指针位置） Y1aF._Z  
private void read_nPos() `=$jc4@J  
{ Yn]yd1  
try{ P|P fG=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Iki+
5  
int nCount = input.readInt(); ) a\DS yr  
nStartPos = new long[nCount]; #0<y0uJ(y  
nEndPos = new long[nCount]; IH5} Az  
for(int i=0;i<nStartPos.length;i++) '7LJuMp$#  
{ ~EWfEHf*BJ  
nStartPos = input.readLong(); t,1!`/\  
nEndPos = input.readLong(); 5QFXj)hR+4  
} h*%0@  
input.close(); D)ne *},  
} 6O@ ^`T  
catch(IOException e){e.printStackTrace ();} m#'rI=}!  
catch(Exception e){e.printStackTrace ();} 2T(,H.O  
} uC*:#[  
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private void processErrorCode(int nErrorCode) c]!D`FA*K  
{ Q @OC=  
System.err.println("Error Code : " + nErrorCode); 8xpYQ<cax  
} 5
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E<#4G9O<  
{F6dSF`  
//停止文件下载 G<^]0`"+)t  
public void siteStop() cYWy\+  
{ w]Ko/;;^2  
bStop = true; 0.BUfuuh  
for(int i=0;i<nStartPos.length;i++) ['Y+z2k  
fileSplitterFetch.splitterStop(); $sL|'ZMbS  
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} NzeI/f3K5  
} )Rhff$  
//负责部分文件的抓取 '
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**FileSplitterFetch.java Oz#EGjz  
*/ ;4/dk_~p]  
package NetFox; *n*N|6+  
SC $`  
<`p75B  
import java.io.*; (XG[_  
import java.net.*; ULNAH`{D  
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public class FileSplitterFetch extends Thread { fr'huvc  
aO^:dl5  
io9xI3{  
String sURL; //File URL +i`Q 7+d  
long nStartPos; //File Snippet Start Position Bd[L6J)  
long nEndPos; //File Snippet End Position JwI`"$>w  
int nThreadID; //Thread's ID te\h?H  
boolean bDownOver = false; //Downing is over y3KcM#[  
boolean bStop = false; //Stop identical "Ql}Y1  
FileAccessI fileAccessI = null; //File Access interface =,AC%S_D~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _Vo)<--+I  
{ R*Xu(89  
this.sURL = sURL; `dgM|.w5=  
this.nStartPos = nStart; kh<pLI>$h  
this.nEndPos = nEnd; iBKb/Oi6  
nThreadID = id; { p!_-sL  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 L8bI0a]r"*  
} _^6|^PT.  
Y(hW(bd;  
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public void run() GJIWG&C03  
{ tIGVB+g{F  
while(nStartPos < nEndPos && !bStop) C@y}*XV[b  
{ pwFU2}I  
${eY9-r_%  
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try{ d)04;[=  
URL url = new URL(sURL); <$i"zb
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :H!(?(Pie  
httpConnection.setRequestProperty("User-Agent","NetFox"); gf68iR.Gs  
String sProperty = "bytes="+nStartPos+"-"; p{ @CoOn  
httpConnection.setRequestProperty("RANGE",sProperty); )|w*/JK\Z  
Utility.log(sProperty); *<*0".#  
-"W)|oC_  
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InputStream input = httpConnection.getInputStream(); #/OUGeJ  
//logResponseHead(httpConnection); _9D|u<D  
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byte[] b = new byte[1024]; G/v|!}?wG  
int nRead; SHMl%mw  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) No:^hY:F8  
{ PC*m% ?+  
nStartPos += fileAccessI.write(b,0,nRead); o_iEkn  
//if(nThreadID == 1) @Z?7E8(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !G7h9CF|{  
} p3g4p
 
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31WZJm^  
Utility.log("Thread " + nThreadID + " is over!"); jvu N  
bDownOver = true; vCj4;P g  
//nPos = fileAccessI.write (b,0,nRead); sF y]+DB  
} |VK:2p^ u  
catch(Exception e){e.printStackTrace ();} S#k{e72 *  
} !~WZ_z  
} Qh^R Ax  
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~]&B>q  
//打印回应的头信息 )]73S@P(=  
public void logResponseHead(HttpURLConnection con) f3!n$lj  
{ H"_v+N5=  
for(int i=1;;i++) {gsW(T>)  
{ QO2Ut!Y  
String header=con.getHeaderFieldKey(i); X<Z(]`i  
if(header!=null) CJp-Y}fGEA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /u=aX  
Utility.log(header+" : "+con.getHeaderField(header)); @l{I[pp
 
else G;NB\3~X  
break; I]jX7.fx  
} ?;^5ghY$  
} YZ< NP  
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7,h3V=^)Q  
public void splitterStop() 9\AS@SH{^T  
{ RJx{e
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bStop = true; q[P~L`h S  
} .a:Z!KF  
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} yX'IZk#_L  
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/* l<xFnj  
**FileAccess.java gLD{1-v  
*//文件访问(定位，写) ,T$r9!WTM  
package NetFox; MqdB\OW&  
import java.io.*; p![&8i@ym  
$6!iBX@  
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public class FileAccessI implements Serializable{ O:JPJ"!  
#h N.=~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 GJ`UO  
RandomAccessFile oSavedFile; C_G1P)k  
long nPos; +9zA^0  
:!O><eQw  
;& ~929  
public FileAccessI() throws IOException EeB3 }  
{ cy3M^_5B<  
this("",0); <HF-2?`  
} JYV\oV{  
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76u{!\Jo/{  
public FileAccessI(String sName,long nPos) throws IOException
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{ yp+F<5o  
oSavedFile = new RandomAccessFile(sName,"rw");
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this.nPos = nPos; r6t&E%b  
oSavedFile.seek(nPos); jDTUXwx7V  
} 1lcnRHO  

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public synchronized int write(byte[] b,int nStart,int nLen) W:O0}  
{ cPuHLwwYf  
int n = -1; CH;;V3  
try{ J8;Okzb!L  
oSavedFile.write(b,nStart,nLen); M|r8KW~S)  
n = nLen; o56
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} z+/LS5$  
catch(IOException e) |$e:*  
{ 4j3oT)+8  
e.printStackTrace (); bulboyA&#
 
} O2v.  
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return n; .pvxh|V  
} "HC)/)Mv@  
<Wy>^<`  
<&U!N'CE  
} JJ5C}`(  
doD>m?rig3  
YwAnqAg  
/* ,4Y*:JU4  
**SiteInfoBean.java ^,V[nfQR  
*/ KzVTkDn,  
package NetFox; #C\4/g?=,  
|+NuYz?  
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public class SiteInfoBean { Y&~M7TYb  
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private String sSiteURL; //Site's URL ~>%DKJe  
private String sFilePath; //Saved File's Path !Iq{ 5:  
private String sFileName; //Saved File's Name wFL3
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private int nSplitter; //Count of Splited Downloading File 70Ka!  
\+Y!ILOI  
n )K6i7]xk  
public SiteInfoBean() onl>54M^  
{//nSplitter的缺省值为5 Q6^
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//default value of nSplitter is 5 g-@h>$< 1  
this("","","",5); EXpSh}  
} I]uhi{\C  
]}2Ztr)zZ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~7SH4Cr  
{ nG
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sSiteURL= sURL; J_xG}d  
sFilePath = sPath; 0"4@;e_)>  
sFileName = sName; ]k+m=OR{/  
this.nSplitter = nSpiltter; z $6JpG  
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(@&I_>2Q  
} c> G@+  
8$}OS-  
#":a6%0Q  
public String getSSiteURL() zvf3b!}  
{ 8tQ|-l*  
return sSiteURL; -M61Mw1  
} 0kL
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X?dfcS*!n  
T1NH eH>  
public void setSSiteURL(String value) /iC_!nu  
{ *fhX*e8y  
sSiteURL = value; e4.&aIC[  
} r!K|E95oj9  
KQ)T(mIqp  
N@1p]\  
public String getSFilePath() E`AYee%l  
{ 0HbJKix!  
return sFilePath; JR1
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} =`p&h}h-L  
xzikD,FV  

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public void setSFilePath(String value) qrDcL>Hrn  
{ GS%b=kc  
sFilePath = value; M#M?1(O/NE  
} i6>R qP!69  
.#!mDlY;  
GZ3/S|SMP  
public String getSFileName() Q]\j>>  
{ )w"0w(  
return sFileName; &O tAAE  
} v~5<:0dL  
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public void setSFileName(String value) rJ(OAKnY  
{ YzV(nEW  
sFileName = value; k18$JyaG  
} t!jwY/T  
NG9vml  
;$;rD0i|  
public int getNSplitter() <SQ(~xYi
  
{ !6E:5=L^  
return nSplitter; Y/P]5: =h  
} G(\Ckf:  
^saM$e^c:  
sqG`"O4W  
public void setNSplitter(int nCount) }n95< {  
{ wLMvC{5  
nSplitter = nCount; J @B4 R&V  
} 4oJ$dN  
} #!d]PH746  
}vD;DSz:  
R3G@G  
/* {^wdJZ~QLK  
**Utility.java xid:"y=_&  
*/ ]fC7%"nB  
package NetFox; $8@+j[>  
;[~^(. f  
UE7'B?  
public class Utility { ysVi3eq  
oCA(FQ6  
KZ3B~#oQ  
public Utility() `[@VxGy_  
{ K;C_Z/<%  
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%M6 c0d[9-  
} qUg9$oh{LI  
Ky6+~>  
//线程睡眠 8KKz5\kn7  
public static void sleep(int nSecond) xgs@gw7!n0  
{ DZP*x  
try{ KcnjF^k  
Thread.sleep(nSecond); o"4E+1qwM  
} HSC6;~U  
catch(Exception e) j"0rkN3$J  
{ \H[Yyp4  
e.printStackTrace (); N5ci};?  
}
}v&K~!*  
} lfRH`u  
<dS5|||  
//日志 kAt RY4p  
public static void log(String sMsg) L^x5&CCwk  
{ 2;h+;G  
System.err.println(sMsg); S<9gyW  
} P]-#wz=S  
eN4t1$  
}Wqtip:L  
public static void log(int sMsg) D>S8$]^Dm  
{ "H
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System.err.println(sMsg); eZA6D\  
} *cPN\Iu.W  
} mfz"M)1p1  
&hO$4qtN  
=I7[L{+~Y  
/* TX&[;jsj  
**TestMethod.java K[n<+e;G  
*/ ~R)1nN|  
package NetFox; G}Gb|sD Zq  
Z`|>tbOfZ  
>}mNi:6xq  
public class TestMethod { 3Nc'3NPQ'  
]Kof sU_{  
C"k2<IE  
public TestMethod() \ =S3 L<  
{ ///xx/weblogic60b2_win.exe <yis  
try{ &t[z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?a*fy}A|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !If
I-Q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); qn5yD!1  
fileFetch.start(); -bv>iIC  
} L[`R8n1C  
catch(Exception e){e.printStackTrace ();} `i"$*4#<  
=ZxW8DK  
3WQRN_  
} Y:DNu9  
+s#S{b  
le "JW/BD  
public static void main(String[] args) Bl>_&A)  
{  Oz"@yL}  
new TestMethod(); 67Af} >Q  
} T*7S;<2  
} RTdD]pE8Q  
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