http断点续传简单实现（java)

/* t[HfaW1W  
**SiteFileFetch.java mx`QBJ  
*/ $ ?ayE  
package NetFox; m-V_J`9"  
import java.io.*; >bQ'*!  
import java.net.*; a,<l_#'  
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public class SiteFileFetch extends Thread { fTb&k;'LR<  
#mhR^60,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [D/q  
long[] nStartPos; //开始位置 `M0m`Up  
long[] nEndPos; //结束位置 } a#RX$d&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "u#,#z_  
long nFileLength; //文件长度 p0c*)_a*  
boolean bFirst = true; //是否第一次取文件 )fPN6x/e  
boolean bStop = false; //停止标志 /2 V  
File tmpFile; //文件下载的临时信息 x-0O3IIE  
DataOutputStream output; //输出到文件的输出流 tf1iRXf8  
pC=kvve  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） WC2sRv4]3  
public SiteFileFetch(SiteInfoBean bean) throws IOException D^]g`V*N  
{ hnOo T? V  
siteInfoBean = bean; IRWVoCc9/\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p7H0|>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g!/O)X3  
if(tmpFile.exists ()) Ife/:v  
{ >@Vap  
bFirst = false; =i'APeNaQ  
read_nPos(); 3a|I| NP  
} Sfl. &A(  
else >;wh0dBe  
{ -zn$h$N4  
nStartPos = new long[bean.getNSplitter()]; *@;Pns]L-  
nEndPos = new long[bean.getNSplitter()]; ),DLrGOl  
} {tE9m@[AF  
=;HC7TUM&  
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} BqoGHg4iq  
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i n$~(+  
public void run() pNt,RRoR  
{ `MD%VHQ9U  
//获得文件长度 5?] Dn k.o  
//分割文件 0oT~6BGm  
//实例FileSplitterFetch a!?JVhD&  
//启动FileSplitterFetch线程 8.`*O  
//等待子线程返回 },eV?eGj  
try{ Q)mYy
  
if(bFirst) TR7j`?  
{
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nFileLength = getFileSize(); (:|g"8mQm  
if(nFileLength == -1) QOT|6)Yb  
{ qDlh6W?}k  
System.err.println("File Length is not known!"); _bsAF^ ;  
} UnVYGch  
else if(nFileLength == -2) -l(G"]tRB  
{ CdZS"I  
System.err.println("File is not access!"); g \;,NW^  
} :{8,O-  
else 8uh^%La8b.  
{ YY4XCkt  
for(int i=0;i<nStartPos.length;i++) k-CW?=  
{ }Od=WQv+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #(Xv\OE  
} AHB_[i'>7  
for(int i=0;i<nEndPos.length-1;i++) z^,P2kqK_  
{ %fJ~3mu  
nEndPos = nStartPos[i+1]; _P}wO8  
} O su 75@3  
nEndPos[nEndPos.length-1] = nFileLength; Rz03he  
} lVptA3
F  
} ;Q.'u  
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8x~'fzf;Sq  
//启动子线程 9*Z!=Y#4,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f%[0}.
wp  
for(int i=0;i<nStartPos.length;i++) 8T523VI  
{ Q8h0:Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q1Sr#h|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /mK."5-cm  
nStartPos,nEndPos,i); .ri?p:a}w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o;[cApiQ,2  
fileSplitterFetch.start(); r"4&.&6  
} e'dx Y(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?B{,%2+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); P*!~Z*"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9O4\DRe5c  
nEndPos = " + nFileLength); zkm#w  
// fileSplitterFetch[nPos.length-1].start(); -`cNRd0n  
*L{^em#b  
rnSrkn"j{  
//等待子线程结束 7W.z8>p  
//int count = 0; 4R}$P1 E  
//是否结束while循环 `Lj'2LoER  
boolean breakWhile = false; M+l~^E0Wj  
P[K42mm  
-IE=?23Do?  
while(!bStop) "2_nN]%u-  
{ E0t%]?1  
write_nPos(); UA3!28Y&E3  
Utility.sleep(500); qZ<|A%WQ  
breakWhile = true; /Z1>3=G by  
!QsmT3  
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for(int i=0;i<nStartPos.length;i++) Dzr(Fb  
{ f\u5=!kjN  
if(!fileSplitterFetch.bDownOver) MA+{7 [  
{ !*!i&0QC~R  
breakWhile = false; 6^QSV@N|  
break; /P[@o  
} @W.0YU0|J  
} 2{A/Fbk  
if(breakWhile) BJP^?FUd=,  
break; /St d6B*  
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,<O|#`?"@G  
//count++; k vF[d{l
 
//if(count>4) W@t{pXwLv  
// siteStop(); OI)U c .  
} 1SG^g*mf  
cnL@j_mb  
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System.err.println("文件下载结束！"); WNp-V02l  
} i Qa=4'9;  
catch(Exception e){e.printStackTrace ();} ,|^ lqY  
} H=@S+4_bK  
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//获得文件长度 S{S.H?{F  
public long getFileSize() +5N09$f;R  
{ 1Gp|_8  
int nFileLength = -1; 7e/K YS+!s  
try{ rPx:o}&<  
URL url = new URL(siteInfoBean.getSSiteURL()); |IZ
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); um=qT)/D  
httpConnection.setRequestProperty("User-Agent","NetFox"); |>dqZ_)v  
K!O7q~s[D  
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int responseCode=httpConnection.getResponseCode(); 'fka?lL  
if(responseCode>=400) 9RQw6rL  
{ w9,w?
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processErrorCode(responseCode); CuAA)Bj  
return -2; //-2 represent access is error V\/5H~L  
} @u1mC\
G  
8;fi1 "F;}  
+"3K)9H  
String sHeader; #vPf$y6jCI  
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zuYz"-(L  
for(int i=1;;i++) x}7`Q:k=  
{ - -ZSl  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %&&;06GU}  
//Utility.log(in.readLine()); `y*o-St3  
sHeader=httpConnection.getHeaderFieldKey(i); ZJ'FZ8Sx  
if(sHeader!=null) Uq=!>C8  
{ 8
?[#\KgH1  
if(sHeader.equals("Content-Length")) e$4$G<8;y  
{ kWxcB7)uk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); OcZ8:`=%  
break; deqL  
} !3Ed0h]Bfa  
} 8gXf4A(N  
else +7$zL;ph=n  
break; e)kVS}e?  
} [' cq  
} (k<__W c_t  
catch(IOException e){e.printStackTrace ();} o]WG8Mo-  
catch(Exception e){e.printStackTrace ();} X@^"@  
7rjS.  
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Utility.log(nFileLength); P7y.:%DGD0  
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9Fh1rZD<  
return nFileLength; 822jZ sb  
} *K=Yrisz  
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\"  
//保存下载信息（文件指针位置） ;0Mg\~T~'  
private void write_nPos() > m##JzWLr  
{ k-|b{QZ8!;  
try{ O_|p{65
  
output = new DataOutputStream(new FileOutputStream(tmpFile)); EM0]"s@Lf  
output.writeInt(nStartPos.length); BLcsIyq  
for(int i=0;i<nStartPos.length;i++) T)#eaz$4W  
{ $
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// output.writeLong(nPos); rhO8v  
output.writeLong(fileSplitterFetch.nStartPos); Qh!h "]  
output.writeLong(fileSplitterFetch.nEndPos); (7?jjH^4  
} !/6KQdF  
output.close(); >o8N@`@VK-  
} Bw*
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catch(IOException e){e.printStackTrace ();} /]hE?cmj  
catch(Exception e){e.printStackTrace ();} 3PRK.vf  
} x L]Z3"p%  
8L,i}hIo.  
&J}w_BFww  
//读取保存的下载信息（文件指针位置） 9/4Bx!~A  
private void read_nPos() K91.-k3)$  
{ Cl'3I%$8K  
try{ )+v'@]r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {,
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int nCount = input.readInt(); ;&U! g&  
nStartPos = new long[nCount]; [B"CNnA  
nEndPos = new long[nCount]; WoX,F1o  
for(int i=0;i<nStartPos.length;i++) a!*K)x,"<  
{ i~;Yrc%AEX  
nStartPos = input.readLong(); ~4C:2  
nEndPos = input.readLong(); bT#re  
} vGI?X#w3  
input.close(); D?@e,e  
} 1,(uRS#bk  
catch(IOException e){e.printStackTrace ();} XdGA8%^cY  
catch(Exception e){e.printStackTrace ();} DgRA\[c  
} #`b5kqQm  
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private void processErrorCode(int nErrorCode) ;sfk@ec  
{ E|5lm  
System.err.println("Error Code : " + nErrorCode); M`gr*p  
} Yn1CU  
Fc.1)yh.  
:}}~ $$&  
//停止文件下载 u<a =TPAU  
public void siteStop() sN9 SuQ  
{ EE[JXoke  
bStop = true; /{+77{#Qn  
for(int i=0;i<nStartPos.length;i++) \<4Hp_2?  
fileSplitterFetch.splitterStop(); fk  
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} X/-u$c  
} v %GcNjZk5  
//负责部分文件的抓取
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**FileSplitterFetch.java A3c&VT6Q  
*/ ;,Q6AS!
 
package NetFox; (N`x  
84UI)nE:Q  
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import java.io.*; :c^9\8S  
import java.net.*; _$YT*o@0J  
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public class FileSplitterFetch extends Thread { SwVdo|%.?  
3^J~ts{*  
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String sURL; //File URL ;^Y]nsd  
long nStartPos; //File Snippet Start Position ?f ]!~  
long nEndPos; //File Snippet End Position F^)SQ%xx  
int nThreadID; //Thread's ID t ]yD95|  
boolean bDownOver = false; //Downing is over D?<R5zp  
boolean bStop = false; //Stop identical c DO<z  
FileAccessI fileAccessI = null; //File Access interface dLIZ)16&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException k6PHyt`3'  
{ QwL'5ws{q  
this.sURL = sURL; sU}.2k  
this.nStartPos = nStart; FsyM{LT  
this.nEndPos = nEnd; c<J/I_!  
nThreadID = id; WG?;Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~Q/G_^U:  
} tW#=St0<.o  
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public void run() :w5p#+/,P  
{ Rr0@F`"R  
while(nStartPos < nEndPos && !bStop) r:*0)UZlD  
{ }xE}I<M  
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try{ %.+#e  
URL url = new URL(sURL); =fZMute  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >84:1`  
httpConnection.setRequestProperty("User-Agent","NetFox"); E8QY6gKF  
String sProperty = "bytes="+nStartPos+"-"; !1s^TB>N  
httpConnection.setRequestProperty("RANGE",sProperty); t)hAD_sf  
Utility.log(sProperty); :Kt'Fm,s?  
}3&~YBx;:  
#0wH.\79  
InputStream input = httpConnection.getInputStream(); wqyrs|P  
//logResponseHead(httpConnection); TaN]{k  
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byte[] b = new byte[1024]; r
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int nRead; 6s$jt-bH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /y<nAGtD&  
{ <h7FS90S  
nStartPos += fileAccessI.write(b,0,nRead); &lp5W)D  
//if(nThreadID == 1) s wIJmA  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0~0OQ/>7  
} Ws>2S  
fqcFfz6?x  
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Utility.log("Thread " + nThreadID + " is over!"); PfKF!/c B  
bDownOver = true; u:FFZ  
//nPos = fileAccessI.write (b,0,nRead); erC)2{m  
} Qso"jYl<  
catch(Exception e){e.printStackTrace ();} V<+=t{  
} j~a"z4
0  
} 6YCFSvA#/  
k-uwK-B}v+  
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//打印回应的头信息 @h&crI[c  
public void logResponseHead(HttpURLConnection con) ?UPZ49y  
{ Z[{k-_HgAm  
for(int i=1;;i++) uK5&HdoM  
{ Q-:IE T  
String header=con.getHeaderFieldKey(i); +g6t)Gl  
if(header!=null) W$X@DXT=o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \&S-lsLY  
Utility.log(header+" : "+con.getHeaderField(header)); UFLN/  
else ;F:~HrxT}  
break; =gjq@N]lAW  
} S
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} b
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jbU=D:|  
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public void splitterStop() 1 ynjDin<  
{ T1&^IO-F7$  
bStop = true; 3Wl,T5}{  
} V>YZ^>oeH  
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} x/pM.NZF1  
v_$'!i$  
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/* lW!}OzE(m  
**FileAccess.java _FJ,, /~  
*//文件访问(定位，写) Zss `##  
package NetFox; !7KSNwGu  
import java.io.*; GkT:7`|C  
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HaUfTQ8  
public class FileAccessI implements Serializable{ ZM~kc|&  
xp4w9.X5(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 yl=_ /'*  
RandomAccessFile oSavedFile; UY!N"[&  
long nPos; 5:o$]LkOWC  
*61+Fzr  
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public FileAccessI() throws IOException 4%3R}-'mh  
{ S-8wL%r  
this("",0); JFvVRGWB  
} RK
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public FileAccessI(String sName,long nPos) throws IOException .Kn)sD1  
{ D]s8w  
oSavedFile = new RandomAccessFile(sName,"rw"); !p4y@U{  
this.nPos = nPos; p..O;_U  
oSavedFile.seek(nPos); z DP  
} .)zX<~,  
9b/7~w.  
)tRqt9Th*  
public synchronized int write(byte[] b,int nStart,int nLen) sU/R$Nbr  
{ 7HpfHqJ7  
int n = -1; H</Mh*Fl2G  
try{ 99\;jz7  
oSavedFile.write(b,nStart,nLen); ?ep'R&NV  
n = nLen; F>0[v|LG  
} UA{tmIC\  
catch(IOException e) U%7| iK  
{ ~_z"So'|F_  
e.printStackTrace (); nJvDkh#h1  
} (L{Kg U&{$  
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return n; t~luBUF  
} %4%$NdU"  
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} Gl1Qbd0  
^+ hJ& 9W  
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/* cPemrNxydN  
**SiteInfoBean.java ;}t
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*/ *6-fvqCv  
package NetFox; Zewx*Y|
 
wQ7G_kVp  
lE8M.ho\  
public class SiteInfoBean { 0{8^)apII  
AF=9KWqf  
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private String sSiteURL; //Site's URL P~>E  
private String sFilePath; //Saved File's Path j &#A 9!  
private String sFileName; //Saved File's Name )]=1W  
private int nSplitter; //Count of Splited Downloading File FAS+*GFz  
=9lrPQ]w  
1;\A./FVv  
public SiteInfoBean() a^vXwY  
{//nSplitter的缺省值为5 #!m`A+!~!  
//default value of nSplitter is 5 8fn7!  
this("","","",5); PjH[8:,  
} PFqc
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y;!qE~!3  
{ `Jvy~T  
sSiteURL= sURL; bN,>,hj  
sFilePath = sPath; aAlES< r  
sFileName = sName; LIo3a38n?y  
this.nSplitter = nSpiltter; C)7T'[  
+B 4&$z  
$#cZJ@;]  
} 'THcO*<  
92@/8,
[  
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public String getSSiteURL() ;{n@hM*O  
{ eb])=  
return sSiteURL; .HM1c  
} [3yzVcr~4  
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23lLoyN  
public void setSSiteURL(String value) p)t1]<,Of  
{ _h% :Tu  
sSiteURL = value; $=x1_  
} !besMZ  
;B35E!QJ  
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public String getSFilePath() U{IY F{;@  
{ 2k }:)]m  
return sFilePath; ^4+ew>BLSv  
} ;g3z?Uz)  
Q^&oXM'x/i  
5wy1%/;  
public void setSFilePath(String value) hPCt-  
{ Bf72 .gx{0  
sFilePath = value; ~wMdk9RQ  
} Bs@!S?  
6@7K\${  
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public String getSFileName() A
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{ .4M8  
return sFileName; )HrFWI'Y  
} Ub0hISA  
!)jw o=l}J  
^w0V{qF{  
public void setSFileName(String value) 61Z#;2]  
{ (M1HNIM;(  
sFileName = value; O'6zV"<P  
} p.r \|  
Zz"b&`K  
uHBEpqC%  
public int getNSplitter() ZP@or2No%  
{ +d[A'&"  
return nSplitter;
*]ROUk@K=  
} bv.DW,l%'  
Q?f%]uGFQ  

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public void setNSplitter(int nCount) }Yi)r*LI3  
{ dmq<vVxC  
nSplitter = nCount; tSST.o3  
} C~do*rnM^  
} p!+7F\  
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e&Z\hZBb  
/* T;cyU9  
**Utility.java T ;Ga G  
*/ NDw+bR-  
package NetFox; 59?@55  
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public class Utility { <b-BJ2],k  
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pK)*{fC$`  
public Utility() p^2"g~  
{ i\P?Y(-{  
-
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45Z"U<I,9  
} 8+m[ %5lu  
Qfhhceb6#J  
//线程睡眠 U=?hT&w\S  
public static void sleep(int nSecond) UbBo#(TZ)  
{ R&z)  
try{ qz|`\^  
Thread.sleep(nSecond); )+^1QL  
} omxBd#;F$  
catch(Exception e) T&?0hSYt  
{ z|Z<S+=f  
e.printStackTrace ();  &cjE+  
} kzA%.bP|  
} U'pm5Mc\q  
Zk#^H*jgx  
//日志 tEz6B}  
public static void log(String sMsg) P;&rh U^[  
{ <Tq&Va_w  
System.err.println(sMsg); 0nkon3H  
} -rU~  
*wNX<R.  
ryz [A:^G  
public static void log(int sMsg) #z|\AmZ\  
{ G;:D6\  
System.err.println(sMsg); ^y@RfM=A  
} ~<M/<%o2*  
} ]!>ThBMa  
~|j:xM(i  
9NH"Ik*  
/* 6E9y[ %+  
**TestMethod.java )P6n,\  
*/
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package NetFox; jL$&]sQ`O)  
| v? pS  
t6.hg3Y  
public class TestMethod { RU>Hr5ebo  
p_!;N^y.  
O<3i6  
public TestMethod() PZ/gD  
{ ///xx/weblogic60b2_win.exe %G%##wv:  
try{ *7"R[!9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); > ,L'A;c}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Oeo:
V"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H].G%,2'  
fileFetch.start(); UcCkn7}  
} s*R\!L  
catch(Exception e){e.printStackTrace ();} Zk+J=Cwq}  
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{VC4rA  
} s52c`+  
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public static void main(String[] args) By=/DVm)=  
{ qyP|`Pm4  
new TestMethod(); zy(i]6  
} 1'5I]D ec  
} <B]\&  
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