http断点续传简单实现（java)

/* LtKR15h,  
**SiteFileFetch.java *&h]PhY  
*/ I.~=\%Z{  
package NetFox; !mwMSkkq  
import java.io.*; b`DPlQHj  
import java.net.*; ZdPqU\G^q  
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public class SiteFileFetch extends Thread { /1.Z=@7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean SymlirL  
long[] nStartPos; //开始位置 *] >R  
long[] nEndPos; //结束位置 f/0k,~,*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B(eiRr3  
long nFileLength; //文件长度 T0b/txS  
boolean bFirst = true; //是否第一次取文件 R@>^t4#_Q0  
boolean bStop = false; //停止标志 ^)|tf\4  
File tmpFile; //文件下载的临时信息 GH3RRzp r  
DataOutputStream output; //输出到文件的输出流 Y[rCF=ZVH  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ! z5c+JqN  
public SiteFileFetch(SiteInfoBean bean) throws IOException J5Q.v;  
{ )S#?'gt*  
siteInfoBean = bean; UxMei  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WigTNg4  
if(tmpFile.exists ()) 2sEG#/Y=  
{ }#=t%uZ/  
bFirst = false; fmLDufx  
read_nPos(); 3{ea~G)[9  
} I-kK^_0mV<  
else fti0Tz'  
{ _KyhX|  
nStartPos = new long[bean.getNSplitter()]; Ar_Yl
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nEndPos = new long[bean.getNSplitter()]; W%9~'pXgB  
} h*Mi/\  
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} ]'>jw#|h  
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public void run() W55kR.X6M  
{ &a\G,Ma  
//获得文件长度 :Z83*SPc  
//分割文件 u2I@ fH/  
//实例FileSplitterFetch a|]}uFr  
//启动FileSplitterFetch线程 D&],.N  
//等待子线程返回 c% ?@3d  
try{ bpDlFa  
if(bFirst) G \$x.  
{ =4!m]*y  
nFileLength = getFileSize(); ^0
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if(nFileLength == -1) fX1Ib$v  
{ `:0Auw9h  
System.err.println("File Length is not known!"); C8(0|XX  
} "0z4mQ}>N  
else if(nFileLength == -2) XN3'k[  
{ wjOJn]  
System.err.println("File is not access!"); (&_~eYZU  
} yVpru8+eD  
else |gT8QP  
{ R"z}q(O:  
for(int i=0;i<nStartPos.length;i++) ^ZBTd5t#  
{ /}eb1o  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %h
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} E429<LQI/  
for(int i=0;i<nEndPos.length-1;i++) Q5 o0!w  
{ usi3z9P>n  
nEndPos = nStartPos[i+1]; #nj;F'O](  
} z\WyL;  
nEndPos[nEndPos.length-1] = nFileLength; *d 4
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} lgbq^d  
} srKEtd"  
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_vAc/_N  
//启动子线程 F"' (i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 52'6wwv6?  
for(int i=0;i<nStartPos.length;i++) $$B#S'  
{ [l~G7u.d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DTdqwe6pi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <J}JYT  
nStartPos,nEndPos,i); =66'33l2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n6c+Okj  
fileSplitterFetch.start(); $KoGh_h  
} <?Z]h]C^o  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eZg>]<L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |h.@Xy  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w,<n5dMv  
nEndPos = " + nFileLength); 7eF
FKl  
// fileSplitterFetch[nPos.length-1].start(); ^=gN >xP  
_+Pz~_+kS  
'PTQ S,E  
//等待子线程结束 2frwU~y  
//int count = 0; !bn=b>+  
//是否结束while循环 Q>G% *?  
boolean breakWhile = false; ]KUeSg|  
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>``  
while(!bStop) [[ll4|  
{ TFXKCl  
write_nPos(); $+U6c~^^  
Utility.sleep(500); <Iil*
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breakWhile = true; r#J_;P{U  
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for(int i=0;i<nStartPos.length;i++) ahN8IV=+Gm  
{ ;2aPhA  
if(!fileSplitterFetch.bDownOver) be(hY{y`  
{ /%bnG(4  
breakWhile = false; B~YOU3  
break; /3;]e3x  
} !~xlze  
} /.t1Ow  
if(breakWhile) kJCeQK:W  
break; {=MRJg!U  
TALiH'w6|e  
>h$Q%w{V  
//count++; -6e^`c6{  
//if(count>4) D]WrPWL8v  
// siteStop(); e0]%ko"  
}
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System.err.println("文件下载结束！"); rG%8ugap  
} ZT<VDcP{  
catch(Exception e){e.printStackTrace ();} ~sNBklK  
} sH%Ts@Pl  
wZ_"@j<  
onIZ&wrk  
//获得文件长度 8\+DSA  
public long getFileSize() `~NjBtQ  
{ G#1W":|`  
int nFileLength = -1; "EZpTy}Ee  
try{ BxaGBK<k  
URL url = new URL(siteInfoBean.getSSiteURL()); 4K|O?MUNS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \GZ|fmYn  
httpConnection.setRequestProperty("User-Agent","NetFox"); \0FwxsL  
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int responseCode=httpConnection.getResponseCode(); O;0VKNn['  
if(responseCode>=400) `4ti?^BNm  
{ j-| !QlB  
processErrorCode(responseCode); 5inCAPXz  
return -2; //-2 represent access is error nXERj; Q"  
} 1'1>B  
#@E:|^$1y  
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String sHeader; ;"8BbF.  
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for(int i=1;;i++) (g1Op~EM  
{ jPn.w,=)27  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N7_(,Gu*R  
//Utility.log(in.readLine()); )&%Y{a#  
sHeader=httpConnection.getHeaderFieldKey(i); hd`jf97*  
if(sHeader!=null) z]2lT IWg  
{ $h5QLN   
if(sHeader.equals("Content-Length")) J.]`l\

 
{ (#]9{C;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ``>z8t[ks  
break; X(Z(cY(  
} @S6@pMo,  
} Z1]4:  
else #];ulDq  
break; Af}o/g  
} |<uBJ-5  
} g@Rs.Zq  
catch(IOException e){e.printStackTrace ();} 7JBr{3;eS  
catch(Exception e){e.printStackTrace ();} v<mSd2B*  
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#8y"1I=i&  
Utility.log(nFileLength); wn\R|'Rdz  
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return nFileLength; ^~dC&!D  
} 3Z7gPU!H=  
d ]jF0Wx*  
3EE_"}H>  
//保存下载信息（文件指针位置） t[MM=6|Wb  
private void write_nPos() imB/P M  
{ alBnN<UM  
try{ 3Zwhv+CP[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _9?v?mL5;  
output.writeInt(nStartPos.length); 5f2=`C0_  
for(int i=0;i<nStartPos.length;i++) { _Y'%Ggh  
{ p[)yn%uh  
// output.writeLong(nPos); .kJu17!  
output.writeLong(fileSplitterFetch.nStartPos); >;%LW} %  
output.writeLong(fileSplitterFetch.nEndPos); J|VDZ# c7  
} Y' 5X4Ks|  
output.close(); ja(ZJ[<`  
} n'%cO]nS
x  
catch(IOException e){e.printStackTrace ();} dV-6l6  
catch(Exception e){e.printStackTrace ();} T&}KUX~Q/  
} b~(S;1NS'  
({D>(xN  
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//读取保存的下载信息（文件指针位置） )19#g1rn5  
private void read_nPos() fUZCP*7>  
{ _rz\[{)  
try{ mP?}h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )}Cf6m}  
int nCount = input.readInt(); yw1Xxwc  
nStartPos = new long[nCount]; '$5d6?BC`3  
nEndPos = new long[nCount]; }g:'K  
for(int i=0;i<nStartPos.length;i++) ac1(lD  
{ @q{.  
nStartPos = input.readLong(); 'ITZz n*  
nEndPos = input.readLong(); :Y4Sdj  
} _xnJfW_  
input.close(); >ul&x!?@  
} !(3[z>  
catch(IOException e){e.printStackTrace ();} r
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catch(Exception e){e.printStackTrace ();} lA
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} dTte4lh  
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private void processErrorCode(int nErrorCode) yh).1Q-D  
{ U!YoZ?  
System.err.println("Error Code : " + nErrorCode); ngk:q5Tp  
} ^ (J%)&_\3  
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//停止文件下载 B[2t.d;h  
public void siteStop() ce719n$   
{ l_,6<wWp  
bStop = true; Mgu9m8 `J  
for(int i=0;i<nStartPos.length;i++) xn)F(P 0kv  
fileSplitterFetch.splitterStop(); }iLi5Qkx  
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} k?/!`  
} RN;#H
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//负责部分文件的抓取 $>Ow<!c  
**FileSplitterFetch.java /q/^B>]  
*/ Kek%io  
package NetFox; tCGA3t  
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import java.io.*; mxe\+j#  
import java.net.*; > kwhZ/x  
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public class FileSplitterFetch extends Thread { a FWTm,)  
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String sURL; //File URL SCfk!GBVD  
long nStartPos; //File Snippet Start Position ETR7%0$r  
long nEndPos; //File Snippet End Position S(rnVsW%Ki  
int nThreadID; //Thread's ID B}aW y&D  
boolean bDownOver = false; //Downing is over F)19cKx7  
boolean bStop = false; //Stop identical 0rif,{"  
FileAccessI fileAccessI = null; //File Access interface >:0N)Pj  
auM1k]  
#W8c)gkG9  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException YF%]%^n  
{ f/Z-dM\e  
this.sURL = sURL; vq@"y%C4  
this.nStartPos = nStart; "u{ymJ]t  
this.nEndPos = nEnd; ;2^zkmDM  
nThreadID = id;
0/cgOP!^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !A14\  
} - 8jlh  
v
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public void run() .dvs&+I  
{ )5Cqyp~P  
while(nStartPos < nEndPos && !bStop) >z,Y%A  
{ &?gcnMg$,J  
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try{ #}8VUbJ  
URL url = new URL(sURL); OSom-?|w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P8tCzjrV  
httpConnection.setRequestProperty("User-Agent","NetFox"); <Zh\6*3:ab  
String sProperty = "bytes="+nStartPos+"-"; ONc#d'-L  
httpConnection.setRequestProperty("RANGE",sProperty); ,3)JZM  
Utility.log(sProperty); r 2{7h>  
@#9xSs#  
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InputStream input = httpConnection.getInputStream(); vJW`aN1<I3  
//logResponseHead(httpConnection); HhzPKd  
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byte[] b = new byte[1024]; 3[~LmA  
int nRead; _sHeB7K  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dp3TJZ+U  
{ n9 Jev_!A  
nStartPos += fileAccessI.write(b,0,nRead); G)""^YB-  
//if(nThreadID == 1) ~\%H0.P6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IY?o \vC  
} bf\ Uq<&IJ  
!'>#!S~h3  
"{jVsih0  
Utility.log("Thread " + nThreadID + " is over!"); `"$9L[>  
bDownOver = true; )F0
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//nPos = fileAccessI.write (b,0,nRead); B\`${O(  
} cL"Ral-qB  
catch(Exception e){e.printStackTrace ();} 5+)_d%v=6!  
} O /h1ew  
} QKoJxjR=^  
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//打印回应的头信息 foI:`]2"*  
public void logResponseHead(HttpURLConnection con) V0gu0+u~R  
{ Pfm B{  
for(int i=1;;i++) lI5>d(6p  
{ rhN"
#?  
String header=con.getHeaderFieldKey(i); /]nrxT  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); >.REg[P  
Utility.log(header+" : "+con.getHeaderField(header)); V.o*`V  
else pU u')y  
break; >Q)S-4iR  
} g G|4+' t  
} 4&~*;an7  
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public void splitterStop() W7IAW7w8U  
{ rE\&FVx  
bStop = true; *`tQX$F  
} U.|0y=  
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} EhN@;D+  
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>lugHF$G  
/* 3LVL5y7|  
**FileAccess.java &2W`dEv]?  
*//文件访问(定位，写) }BCxAwD4  
package NetFox; n$"BF\eM  
import java.io.*; !,*Uvs@b  
2}ywNVS  
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public class FileAccessI implements Serializable{ 6V1 Z(K  
<Oj'0NK-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *(VwD)*  
RandomAccessFile oSavedFile; V_)465g  
long nPos; xf{=~j/L  
^ =H 10A  
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public FileAccessI() throws IOException hrbeTtqi  
{ mpl^LF[  
this("",0); c*)PS`]t  
} W1Om$S1  
?/KkN3Y_j[  
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public FileAccessI(String sName,long nPos) throws IOException l{_1`rC'  
{ 
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oSavedFile = new RandomAccessFile(sName,"rw"); 8noo^QO  
this.nPos = nPos; v1E(K09h2  
oSavedFile.seek(nPos); JRw)~Tg @  
} zZ])G
  
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(m=F  
public synchronized int write(byte[] b,int nStart,int nLen) 0a)LZp|  
{ 4eS(dPI0  
int n = -1; )"^ )Nk  
try{ vslN([@JR  
oSavedFile.write(b,nStart,nLen); p,#**g:  
n = nLen; kn6X I*
 
} _ud!:q  
catch(IOException e) l' a<k"  
{ F#7A6|  
e.printStackTrace (); IQ9Rvnna  
} ==~ lc;  
b_oUG_B3]  
"H)D~K~*  
return n; Z`'&yG;U  
} XO4rrAYvW  
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} .^uYr^(|[  
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/* M'ZA(LVp  
**SiteInfoBean.java %ZZ
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*/ k+Ay^i}s.  
package NetFox; +?bOGU
ik  
VXu1YxY  
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public class SiteInfoBean { K#'{Ko  
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tje  
private String sSiteURL; //Site's URL }G[Qm2k  
private String sFilePath; //Saved File's Path 7_AcvsdW  
private String sFileName; //Saved File's Name 4[m4u6z=  
private int nSplitter; //Count of Splited Downloading File 8E\6RjM  
2sXX0kq~V  
`n~bDG>  
public SiteInfoBean() ngQ]  
{//nSplitter的缺省值为5 !4!Y~7sI"\  
//default value of nSplitter is 5 iY4FOt7\  
this("","","",5); NxQ+z^o\  
} pL)o@-k#%  
u6u1>  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) C<\O;-nHH  
{ 0%<x>O  
sSiteURL= sURL; %$I@7Es>  
sFilePath = sPath; {afR?3GK  
sFileName = sName; ih/MW_t=m=  
this.nSplitter = nSpiltter; HESORa;  
>2?O-WXe  
0=Z_5.T>  
} Z3 $3zyi  
mkOj&Q  
^ G(GjW8  
public String getSSiteURL() (E(k
w="  
{ J^BC  
return sSiteURL; fo30f=^Gi  
} `l8^n0-  
jB!Q8#&Q  
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public void setSSiteURL(String value) AT4G]pT  
{ []rg'9B2b  
sSiteURL = value; _e3kO6X  
} W{2(fb  
8_@#5  
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public String getSFilePath() i-4pdK u  
{ ]Kb3'je  
return sFilePath; &\, ZtaB  
} sOBy)vq?\  
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z  
public void setSFilePath(String value) `kdP)lI `  
{ k )T;WCia  
sFilePath = value; c`(]j w  
} `|i[*+WC  
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public String getSFileName() )wROPA\uA  
{
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return sFileName; p Rn vd|  
} *hp3w  
eh-/,vmRa  
?
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public void setSFileName(String value) hi I`ot  
{ :N<ZO`l?  
sFileName = value; b[3K:ot+  
} :b&O{>M]Y  
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public int getNSplitter() lth t'|  
{ W`
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return nSplitter; h4 s!VK1X  
} ZCZYgf@  
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public void setNSplitter(int nCount) m 4VhR_  
{ _[8BAm  
nSplitter = nCount; 4 |E`  
} !'()QtvC<  
} bojx:g  
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i6p0(OS&D  
/* -o\r]24  
**Utility.java  2L~[dn.s  
*/ VemgG)\  
package NetFox; fT-yY`  
e5_:15%R\  
6Hz45  
public class Utility { gQJy"f  
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public Utility() QQ4  &,d  
{ ]e?cKC\"e  
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}  xA DjQ%B  
.R/`Y)4  
//线程睡眠 |@]`" k  
public static void sleep(int nSecond) }%B^Vl%ZZ  
{ *7'}"@@
 
try{ +SGM3tY  
Thread.sleep(nSecond); 1k2+eI  
} :?VM1!~ga  
catch(Exception e) E4^zW_|xE  
{ Z_oBZs  
e.printStackTrace (); iEG`+h
'  
} fdIk{o  
} A`|OPi)  
,4hQ#x  
//日志 ^[{\ZX  
public static void log(String sMsg) m"P"iK/Av(  
{ 5Uc!;Gd?b  
System.err.println(sMsg); rULrGoM  
} v7+f@Z:N*  
N'nI ^=  
 }xcEWC\  
public static void log(int sMsg) Fh u(u  
{ ^PY*INv  
System.err.println(sMsg); F2yc&mXyk  
} zmH8#  
} ln#Jb&u  
i?uJ<BdU[  
SG1fu<Q6J  
/* t&+f:)n  
**TestMethod.java 3+gp_7L  
*/ X8uVet]D~  
package NetFox; x4jn45]x@  
#F\}PCBe'  
5`oVyxJ<  
public class TestMethod { okx~F9  
&CCp@" +  
(B@:0}>  
public TestMethod() H tIl;E  
{ ///xx/weblogic60b2_win.exe Fv \yhR  
try{ 9ZjSM,+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `<>Emc8Z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); nmlQ-V-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RI_:~^nO{r  
fileFetch.start(); |EuWzhNAO  
} Ur`Ri?
  
catch(Exception e){e.printStackTrace ();} ob=GB71j55  
|A".Mo_5  
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} Wpo:'?!(M^  
P!qU8AJkt  
<^?64  
public static void main(String[] args) &?\
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{ LJK<Xen  
new TestMethod(); ngM>Tzirt  
} W)I)QinOH  
} V QE *B  
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