http断点续传简单实现（java)

/* `Tyd1!~  
**SiteFileFetch.java 2!B|w8ar  
*/ Q}lCQK/g  
package NetFox; &k}B66  
import java.io.*; >(igVaZ>  
import java.net.*; q 9xA.*  
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public class SiteFileFetch extends Thread { "ckK{kS4~  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [5p9p1@u{C  
long[] nStartPos; //开始位置 j0{`7n  
long[] nEndPos; //结束位置 !Ea!"}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h?SRX_  
long nFileLength; //文件长度 E:**gvfq  
boolean bFirst = true; //是否第一次取文件 |LQ%sV  
boolean bStop = false; //停止标志 Z@Q*An  
File tmpFile; //文件下载的临时信息 6X h7Bx1  
DataOutputStream output; //输出到文件的输出流 v(.mM9>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =oL:|$
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public SiteFileFetch(SiteInfoBean bean) throws IOException PL$XXj>|:  
{ JnK<:]LcK  
siteInfoBean = bean; ^"?a)KC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ah7"qv'L\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~//9Nz~;3  
if(tmpFile.exists ()) l%GArH`  
{ MW rhVn{R  
bFirst = false; Y"8@\73(R  
read_nPos(); MjC<N[WO>N  
} TCyev[(  
else _yN5sLLyb  
{ d>)=|  
nStartPos = new long[bean.getNSplitter()]; ZXYyG`3+  
nEndPos = new long[bean.getNSplitter()]; |f$+|9Q?  
} %pjeA[-m#  
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} B;=Z^$%T  
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public void run() ~\NQkaBkY  
{ v%*don  
//获得文件长度 o;Z"I&  
//分割文件 &M?b08  
//实例FileSplitterFetch EEZ~Bs}d  
//启动FileSplitterFetch线程 h]&  
//等待子线程返回 "M iJM+,  
try{ b; C}=gg  
if(bFirst) xJ/)*?@+  
{ =T2SJ)  
nFileLength = getFileSize(); 9;7"S.7AV  
if(nFileLength == -1) @B>D>B  
{ ^ei[1#  
System.err.println("File Length is not known!"); +\_\53  
} BE@(| U  
else if(nFileLength == -2) "QXnE^  
{ \a;xJzc9  
System.err.println("File is not access!"); >>KI_$V  
} )GG9
[%H!  
else 7SJ=2  
{ 6?M/71
 
for(int i=0;i<nStartPos.length;i++) klQmo30i  
{ +:jonN9d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >uYQt~s  
} SceHdx(]  
for(int i=0;i<nEndPos.length-1;i++) $)ka1L"N  
{ KQ]sUNH  
nEndPos = nStartPos[i+1]; ZXb{-b?[`  
} s;oe Qa}TB  
nEndPos[nEndPos.length-1] = nFileLength; hv#$Zo<  
} fWEQ vQ  
} ^ fC2o%3^  
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//启动子线程 `x _(EZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; eJ45:]_%I@  
for(int i=0;i<nStartPos.length;i++) N(4y}-w$  
{ DQW)^j h  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L{jx'[C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D )`(b  
nStartPos,nEndPos,i); &\6},
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aeN #<M&$<  
fileSplitterFetch.start(); 9Xg7=(#  
} ]}b  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tTTHQ7o*BD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "0PsCr}!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {u y^Bui}  
nEndPos = " + nFileLength); b?`2LAgn  
// fileSplitterFetch[nPos.length-1].start(); =6ru%.8U,  
1gBLJ0q  
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//等待子线程结束 &UnhYG{A  
//int count = 0; d*Mqs}8  
//是否结束while循环 fNAW4I I}  
boolean breakWhile = false; iQ Xlz]'  
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while(!bStop) %Jh(5  
{ 9VTAs:0D=  
write_nPos(); EQ^]W-gN  
Utility.sleep(500); R$l- 7YSt  
breakWhile = true; bFN/{^SB  
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for(int i=0;i<nStartPos.length;i++) E]n]_{BN]  
{ H
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if(!fileSplitterFetch.bDownOver) T8g\_m  
{ O0'|\:my  
breakWhile = false; O6?{@l  
break; IYq#|^)5+  
} R3og]=uFzm  
} AC <2.i_  
if(breakWhile) %.`u2'^  
break; a_S`$(7k  
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//count++; _PPC?k{z!  
//if(count>4) j$_?g!I=gK  
// siteStop(); q 6UZ`9&z  
} lbt8S.fx  
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System.err.println("文件下载结束！"); 9[VYd '  
} ;0m J4G  
catch(Exception e){e.printStackTrace ();} iP9]b&  
} XYP RMa?  
iT{4-j7|P4  
`.JW_F)1  
//获得文件长度 L`<#vi  
public long getFileSize() 4rL`||  
{ /q>ExXsEC  
int nFileLength = -1; bf.+Ewb(  
try{ tgCp2`n  
URL url = new URL(siteInfoBean.getSSiteURL()); QChWy`x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +~G:z|k  
httpConnection.setRequestProperty("User-Agent","NetFox"); (@*|[wN  
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int responseCode=httpConnection.getResponseCode(); =/a`X[9vI  
if(responseCode>=400) b*S,8vE]  
{ ] +%`WCr9  
processErrorCode(responseCode); z6M5'$\y  
return -2; //-2 represent access is error Y1r'\@L w  
} vA:ZR=)F  
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gh[q*%#  
String sHeader; .4E24FB[f?  
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for(int i=1;;i++) rU9")4sQ  
{ JE:LA+ (  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |*J;X<Vm  
//Utility.log(in.readLine()); .
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sHeader=httpConnection.getHeaderFieldKey(i); }OcrA/  
if(sHeader!=null) Q?j '4  
{ <HJLs+C  
if(sHeader.equals("Content-Length")) ^pe/~ :a  
{ ']
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ) C~#W  
break; Z)xcxSo  
} : ^}!"4{  
} 9:RV5Dt  
else -tWxBGSa@  
break; @6DKw;Q  
} |b='DJz2  
} dbEXlm  
catch(IOException e){e.printStackTrace ();} yO8@.-jb  
catch(Exception e){e.printStackTrace ();} J|
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Utility.log(nFileLength); LC=M{\  
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return nFileLength; }vB{6E+h/w  
} lgVT~v{U`n  
}Tm+gJA  
In%FOPO  
//保存下载信息（文件指针位置） r`FTiPD.C  
private void write_nPos() #+6j-^<_6  
{ 7W},5c  
try{ V+>RF  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2<0".5+I  
output.writeInt(nStartPos.length); jl7>  
for(int i=0;i<nStartPos.length;i++) /-lW$.+{?  
{ zBTxM
 
// output.writeLong(nPos); +7WpJ;C4  
output.writeLong(fileSplitterFetch.nStartPos); p[WlcbBwT  
output.writeLong(fileSplitterFetch.nEndPos); ZI$P Qz2i  
} X0ugnQ6  
output.close(); qrOesSdc  
} j3w~2q"r  
catch(IOException e){e.printStackTrace ();} %<Qv?`B  
catch(Exception e){e.printStackTrace ();} &=%M("IlD  
} wb#[&2
i  
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//读取保存的下载信息（文件指针位置） ixM#|Y
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private void read_nPos() gP8}d*W%b  
{ h^IizrqU  
try{ Qt'3v"S>)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Tp~Qg{%Og  
int nCount = input.readInt(); Xeis_  
nStartPos = new long[nCount]; [=.iJ5,{2  
nEndPos = new long[nCount]; T[[E)f1[  
for(int i=0;i<nStartPos.length;i++) FR50y+h^$  
{ i/8OC  
nStartPos = input.readLong(); \N?lG q  
nEndPos = input.readLong(); >3p8o@:  
} *hFJI9G  
input.close();  874j9ky[  
} j";L{  
catch(IOException e){e.printStackTrace ();} e5FF'~A%]  
catch(Exception e){e.printStackTrace ();} uW}M1kq?+l  
} ):=8w.yC  
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private void processErrorCode(int nErrorCode) Ygfy;G%  
{ rwwyYIlEg  
System.err.println("Error Code : " + nErrorCode); 'R$/Qt;uA  
} 5A %TpJ  
t]3:vp5N]  
H,/=<Th;i  
//停止文件下载 `7``1TL  
public void siteStop() _q-k1$o
$  
{ %ID48_>*  
bStop = true; )99^58my  
for(int i=0;i<nStartPos.length;i++) 's"aPqF?  
fileSplitterFetch.splitterStop(); 0 >(hiTy<  
)cOBP}j+  
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} Ttb?x<)+8  
}
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//负责部分文件的抓取 tnb'\}Vn  
**FileSplitterFetch.java E7SmiD@)  
*/ 6]!Jo)BF  
package NetFox; N-p||u  
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import java.io.*; b\NY!)B  
import java.net.*; bWCtRli}  
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public class FileSplitterFetch extends Thread { {c $8?6  
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String sURL; //File URL M6Ik'r"M  
long nStartPos; //File Snippet Start Position 'OhGS
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long nEndPos; //File Snippet End Position b
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int nThreadID; //Thread's ID ! v%%_sRV  
boolean bDownOver = false; //Downing is over +WxD=|p;  
boolean bStop = false; //Stop identical lH,/N4r*&  
FileAccessI fileAccessI = null; //File Access interface [m<8SOMG(  
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n;.
);  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4Dd]:2|D  
{ HXB& 6  
this.sURL = sURL; KpQ@cc  
this.nStartPos = nStart; {*F8'6YQ$  
this.nEndPos = nEnd; >#;>6q9_  
nThreadID = id; &]KA%Db2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~^3U@(:  
} 3P'Wk|j  
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public void run() d(D|rf,av  
{ [;C*9Nl  
while(nStartPos < nEndPos && !bStop) 5S! !@P!,  
{ K[-G2  
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try{ )\izL]=!t  
URL url = new URL(sURL); @zsqjm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _^0UK|[  
httpConnection.setRequestProperty("User-Agent","NetFox"); }f6_7W%5  
String sProperty = "bytes="+nStartPos+"-"; *@ S+J$  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty); I<&)P#"  
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InputStream input = httpConnection.getInputStream(); &x[V<
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//logResponseHead(httpConnection); :{#w-oC>6P  
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byte[] b = new byte[1024]; Uo:=-NNI  
int nRead; .Jc<Gg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^"J)^3j<  
{ N/B-u
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nStartPos += fileAccessI.write(b,0,nRead); O 0P4uq  
//if(nThreadID == 1) u>03l(X6f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =kW7|c5Z  
} 5q}7#{A  

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Utility.log("Thread " + nThreadID + " is over!"); 6l(HD([_p  
bDownOver = true; q+9c81b  
//nPos = fileAccessI.write (b,0,nRead); (;nh?"5  
} Bh q]h  
catch(Exception e){e.printStackTrace ();} _s0;mvz'  
} X_wPuU%  
} 6oR5q 4  
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//打印回应的头信息 !ac,qj7spa  
public void logResponseHead(HttpURLConnection con) Vfr.Yoy  
{ ]RI+:f  
for(int i=1;;i++) T^nOv2@,  
{ /Nd`eUn  
String header=con.getHeaderFieldKey(i); JHsxaX;c  
if(header!=null) zW; sr.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pJ@D}2u(  
Utility.log(header+" : "+con.getHeaderField(header)); '!XVz$C  
else oMb@)7
 
break; kfs[*ku  
} rn-CQ2{?  
} 5oY^;)\/  
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public void splitterStop() _VLA2#V>  
{ !='L`.  
bStop = true; ^" UZ.@sq'  
} k4
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} {} Zqaf  
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/* yH',vC.  
**FileAccess.java Sk%*Zo{|  
*//文件访问(定位，写) &^K,"a{  
package NetFox; t`"pn<  
import java.io.*; y9Q.TL>=[  
t
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public class FileAccessI implements Serializable{ $36.*s m  
P^m&oH5]EG  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _G^Cc}X  
RandomAccessFile oSavedFile; 0hOps5c8=  
long nPos; h5 PZ?Zd  
o#=
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"|d# +C  
public FileAccessI() throws IOException bm-&H  
{ %v<BE tq  
this("",0); y3@5~4+  
} /n8\^4{fP{  
C\gKJW^]y@  
;^|:*  
public FileAccessI(String sName,long nPos) throws IOException 8@d@T V!n&  
{ V*F |Yo:  
oSavedFile = new RandomAccessFile(sName,"rw"); C5EaP%s  
this.nPos = nPos; #-bz$w#*  
oSavedFile.seek(nPos); |aS272'  
} G57c 8}\4  
h~u|v[@{J  
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public synchronized int write(byte[] b,int nStart,int nLen) Fz@9
@  
{
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int n = -1; MW|:'D`  
try{ ~qezr\$2  
oSavedFile.write(b,nStart,nLen); CjUYwAy$k  
n = nLen; Yp;?Zq9  
} J42/S [Rt  
catch(IOException e) >AUzsQ  
{ `z<I<  
e.printStackTrace (); 2 UPG8]  
} \MB$Cwc  
+W}6o3x~  
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return n; LHd9q^D  
} x^)W}p"  
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} 6=g! Hs{  
V ^hR%*i'  
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/* #= @?)\~  
**SiteInfoBean.java
k83S.*9Mx  
*/ b-HELS`nX  
package NetFox; jUd)|v+t  
&r1]A&  
O*ER3  
public class SiteInfoBean { sk7]s7  
E$USam  
Pd;Gc@'~  
private String sSiteURL; //Site's URL ecyN};V>  
private String sFilePath; //Saved File's Path o4nDjFhh  
private String sFileName; //Saved File's Name :*WiswMFm  
private int nSplitter; //Count of Splited Downloading File tYCVVs`?  
#i=k-FA)H  
;2l|0:  
public SiteInfoBean() W?D-&X^ny  
{//nSplitter的缺省值为5 _[$,WuG1  
//default value of nSplitter is 5 (0^ZZe`#j  
this("","","",5); )_SpY\J  
} p;.M.  
0n*D](/NK  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Y |9  
{ %`}nP3  
sSiteURL= sURL; @IV,sze  
sFilePath = sPath; qpV"ii  
sFileName = sName; LyRW\\z2  
this.nSplitter = nSpiltter; I*H($ a  
QVo>Uit   
1\-r5e; BE  
} x%T.0@
!8  
8~ u/gM  
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public String getSSiteURL() %#C9E kr  
{ K>G.HN@  
return sSiteURL; h`f$]_c  
} x.Tulo0/  
y'(a:.%I  
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public void setSSiteURL(String value) "w3%BbIx  
{ ]EqwDw4  
sSiteURL = value; ji.T7wn1u  
} ;2[),k  
o2!wz8  
6o4Y]C2W{1  
public String getSFilePath() JJy.)-R  
{ `\J,%J  
return sFilePath; P~s u]+  
} 8&3KVd`  
{%c&T S@s  
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public void setSFilePath(String value) 06]"{2  
{ slAR<8  
sFilePath = value; ]EdZ,`B4  
} B_ bZ
a  
Sg*+!  
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public String getSFileName() CV)K=Br5&_  
{ a9NIK/9  
return sFileName; "EwzuM8f  
} f4$sH/ 2#v  
R5&<\RI0  
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public void setSFileName(String value) R]3j6
\  
{ aNP\Q23D  
sFileName = value; d|>/eb.R  
} 2}15FXgN  
'3?-o|v@D  

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public int getNSplitter() WjOP2CVv|  
{ $$i Gs6az  
return nSplitter; #n]K$k>  
} [:+f Y[4==  
TjHt:%7.  
j8c5_&  
public void setNSplitter(int nCount) C-XJe~  
{ 6q^\pJY%&7  
nSplitter = nCount; hbEqb{#}@  
} _=}.Sg5Q  
} g'cVsO)S  
 aW9\h_$  
_r>kR7A\{  
/* X8):R
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**Utility.java |K9*><P?)2  
*/ 9sI&d  
package NetFox; *7b?.{  
nw(R=C  
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public class Utility { QseV\;z  
ZG-#YF.1  
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public Utility() $9P=  
{ 5)A[NTNJx  
.5);W;`X  
`@ny!S|1/  
} Kg`P@  
e+)y6Q=  
//线程睡眠 hu.p;A3p;  
public static void sleep(int nSecond) g#`}HuPoE  
{ MJkusR/  
try{ &XCP@@T  
Thread.sleep(nSecond); R+z'6&/ =I  
} bg|dV  
catch(Exception e) ZMLN ;.{Na  
{ ;"Aj80  
e.printStackTrace (); -*Tf
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} ',/#|  
} JI cm$  
Jg)( F|>o  
//日志 Y=?{TX=6<[  
public static void log(String sMsg) ]>1`Fa6_  
{ ug.|ag'R  
System.err.println(sMsg); |P`b"x  
} }Xfg~%6  
Bh'!aipk  
&xA>(|a\&-  
public static void log(int sMsg) .)=*Yr M  
{ 9yaTDxB>  
System.err.println(sMsg); ]_|'N7J  
} rIb~@cR
)  
} y4l-o  
+~ Hb}0ry  
V^4v`}Wgx  
/*  ;u[:J  
**TestMethod.java d2d8,Vg  
*/ &n6L;y-  
package NetFox; E0/>E  
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u})*6l.  
public class TestMethod { mln4Vl(l2M  
WrcmC$ff  
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public TestMethod() RyU8{-q  
{ ///xx/weblogic60b2_win.exe 5*+DN U@  
try{ 'J3yJ{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !Z |_3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4_ypFuS^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [VqiF~o,  
fileFetch.start(); Wp+lI1t  
} I?E+  
catch(Exception e){e.printStackTrace ();} O2?yI8|Jn  
EZ:? (|
h  
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} S=lCzL;j"  
[PB73q8  
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public static void main(String[] args) `"PHhCG+z  
{ &@'%0s9g  
new TestMethod(); Z,/^lg c,  
} l1|*(%p?X  
} q'a]D
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