http断点续传简单实现（java)

/* `M,Nd'5&|  
**SiteFileFetch.java E2-ojL[6  
*/ $u&|[vcP0  
package NetFox; |O%:P}6c  
import java.io.*; O<bDU0s{M  
import java.net.*; z,M'Tr.1|  
)2#vhMpdN  
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public class SiteFileFetch extends Thread { h1E 
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SiteInfoBean siteInfoBean = null; //文件信息Bean BZ2nDW*%  
long[] nStartPos; //开始位置 l~CZW*/  
long[] nEndPos; //结束位置 I>d I[U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |
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long nFileLength; //文件长度 |}%(6<  
boolean bFirst = true; //是否第一次取文件 4VC/-.At  
boolean bStop = false; //停止标志 `~0P[>|+  
File tmpFile; //文件下载的临时信息 pEY>A_F  
DataOutputStream output; //输出到文件的输出流 Q;=6ag'  
#`r(zI[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )K8P+zn~  
public SiteFileFetch(SiteInfoBean bean) throws IOException dEL3?-;'  
{ 5Zzr5WM  
siteInfoBean = bean; F
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l&vm[3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); K*0aXr?  
if(tmpFile.exists ()) $+0=GN  
{ lGl[^ 0  
bFirst = false; S_ZLTcq<1  
read_nPos(); 4n#YDZ  
} G]1(X38[si  
else r(pwOOx  
{ }7-7t{G  
nStartPos = new long[bean.getNSplitter()]; `Fz\wPd  
nEndPos = new long[bean.getNSplitter()]; &3jBE--  
} ;HR 6X  
+}kO;\  
4 0p3Rv  
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} MJy;GzJ O  
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public void run() t1G1(F#&%  
{ sM#!Xl;  
//获得文件长度 &G0l&8pa  
//分割文件 VfQMFb',o  
//实例FileSplitterFetch hTlnw[I  
//启动FileSplitterFetch线程 %~][?Y ><  
//等待子线程返回 :D<:N*9i  
try{ TS\9<L9S  
if(bFirst) aQ32p4C  
{ IOSuaLH^  
nFileLength = getFileSize(); c-[Q,c  
if(nFileLength == -1) 4 *Bp  
{ P%.`c?olbs  
System.err.println("File Length is not known!"); L2[Ei|9_  
} jl;kcGE  
else if(nFileLength == -2) N$N;Sw  
{ 5%2ef{T[  
System.err.println("File is not access!"); -}=@ *See#  
} _fVh%_oH1  
else )?!vJb"  
{ MV Hz$hy
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for(int i=0;i<nStartPos.length;i++) l81&[  
{ 6(ka"Vu~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L@)b%Q@a  
} R59
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for(int i=0;i<nEndPos.length-1;i++) 3~cS}N T  
{ h5LJijJ  
nEndPos = nStartPos[i+1]; 4RK.Il*d  
} zAKq7'_=  
nEndPos[nEndPos.length-1] = nFileLength; /Ki0+(4  
} p2pTs&}S  
} Ymwx(Pm  
1<XiD3H;  
a)I=U[  
//启动子线程 pb=jvK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; o|rGy5  
for(int i=0;i<nStartPos.length;i++) ^2&O3s
  
{ e8~62O^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q\&AlV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^q4l4)8jX  
nStartPos,nEndPos,i); mp&Le YYn  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OvyB<r  
fileSplitterFetch.start(); 0C7thl{Dms  
} 1Qp1Es<)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xHM&csL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q#mFN/.(+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u\Nw:Uu i  
nEndPos = " + nFileLength); yDCooX0  
// fileSplitterFetch[nPos.length-1].start(); ?=/}Ft  
qB+:#Yrx/  
"<cB73tY  
//等待子线程结束 G/LXUhuif  
//int count = 0; *@-q@5r}
!  
//是否结束while循环 !7O=<  
boolean breakWhile = false; f^[{k {t  
[#STR=_f  
nJ'>#9~a'>  
while(!bStop)
#VQGN2bK.  
{ 'gk81@|  
write_nPos(); r|JiGj^om  
Utility.sleep(500); }\`-G+i{W  
breakWhile = true; 'y+bx?3Z  
~n8*@9[  
6*(h9!_T1  
for(int i=0;i<nStartPos.length;i++) vUo.BA#;.b  
{ v2Qc}o  
if(!fileSplitterFetch.bDownOver) t9f4P^V`  
{ 0aTEJX$iZ  
breakWhile = false; `aO@N(  
break; 4t%:O4 3e  
} t]u(jX)  
} 3IJI5K_  
if(breakWhile) T;4gcJPn"M  
break; !7Yt`l$$z  
lt2Nwt0bv  
Y1Gg (z  
//count++; 3G%XG{dg  
//if(count>4) 2h|(8f:y  
// siteStop(); /
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}
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System.err.println("文件下载结束！"); SSL%$:l@  
} b68G&z>   
catch(Exception e){e.printStackTrace ();} Vav+$l|j@  
} #T$'.M  
MoKXl?B<  
|;Se$AdT#  
//获得文件长度 )]>i>  
public long getFileSize() cvs"WX3  
{ ;)=zvr17  
int nFileLength = -1; |4p<T!T  
try{ )/+eLRN5G  
URL url = new URL(siteInfoBean.getSSiteURL()); @KXz4PU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sS1J.R  
httpConnection.setRequestProperty("User-Agent","NetFox"); o7@4=m}  
SqA+u/"j2  
:,}:c%-^"  
int responseCode=httpConnection.getResponseCode(); nuQLq^e  
if(responseCode>=400) _#^A:a^e8  
{ R.2KYhp,  
processErrorCode(responseCode); rmg";(I  
return -2; //-2 represent access is error |S>J<]H p  
} ?{.b9`  
8x^H<y=O  
\@PUljU]  
String sHeader; 7QOC]:r  
|b
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for(int i=1;;i++) pRxlvVt  
{ xo)?XFM2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -MHX1`P:Sn  
//Utility.log(in.readLine()); ]/VIff  
sHeader=httpConnection.getHeaderFieldKey(i); V=l Q}sBY  
if(sHeader!=null) Lm*LJ_+ B  
{ ;FgEE%  
if(sHeader.equals("Content-Length")) `~aLSpB65  
{ U+RCQTo  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !irX[,e  
break; /m{?o  
} 8|jX ~f  
} R0YC:rAt  
else {^$"/hj  
break; e/HX,sf_g  
} WEV{C(u<k!  
} K}5$;W#  
catch(IOException e){e.printStackTrace ();} vu.S>2Wv  
catch(Exception e){e.printStackTrace ();} s!o<Pd yJK  
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1O3<%T#LOZ  
Utility.log(nFileLength); c;|&>Fp  
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=  
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return nFileLength; l&^[cR  
} _7j/[  
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#;*ai\6>vD  
//保存下载信息（文件指针位置） A^Hp#b@  
private void write_nPos() 9 K /  
{ &A5[C{x  
try{ Jn:GA@[I  
output = new DataOutputStream(new FileOutputStream(tmpFile)); a+a%}76N  
output.writeInt(nStartPos.length); >A'!T'"~  
for(int i=0;i<nStartPos.length;i++) m1$P3tZPn  
{ VzYP:QRz  
// output.writeLong(nPos); ,YMdXYu`s  
output.writeLong(fileSplitterFetch.nStartPos); k#=leu"I  
output.writeLong(fileSplitterFetch.nEndPos); 7quwc'!  
} r+#V{oE_  
output.close(); {}_Oo%IVGK  
} n,Mw# r?y  
catch(IOException e){e.printStackTrace ();} k}0  
catch(Exception e){e.printStackTrace ();} ={i&F  
} +$mskj0s  
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//读取保存的下载信息（文件指针位置） by y
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private void read_nPos() O"-PNF,J  
{ _467~5JkU  
try{ A[$wxdc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qyBK\WqaP  
int nCount = input.readInt(); )J6b:W  
nStartPos = new long[nCount]; fi4/@tV?$L  
nEndPos = new long[nCount]; eP'kY(g8   
for(int i=0;i<nStartPos.length;i++) sK9h=J;F/  
{ JK8@J9(#  
nStartPos = input.readLong(); ?>\]%$5o  
nEndPos = input.readLong(); $Q$d\Yvi  
} BLH3$*,H  
input.close(); ,l?76g  
} fUWm7>6VA>  
catch(IOException e){e.printStackTrace ();} 5~R{,]52  
catch(Exception e){e.printStackTrace ();} S| -{wC%  
} FivaCNA  
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private void processErrorCode(int nErrorCode) 
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{ I8%'Z>E(  
System.err.println("Error Code : " + nErrorCode); B)cb}.N:  
} NizJq*V>  
.-26 N6S  
dSOn\+  
//停止文件下载 YK+Z0ry  
public void siteStop() .6/p4OR|  
{ r|F,\fF  
bStop = true; <@j  
for(int i=0;i<nStartPos.length;i++) BHE =Zo  
fileSplitterFetch.splitterStop(); np>!lF:  
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0  
} Jsnmn$C  
} [[DFEvOEh  
//负责部分文件的抓取 3@ukkO)   
**FileSplitterFetch.java 5'Ay@FJ:  
*/ qlT:9*&g  
package NetFox; +~k,4  
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import java.io.*; E|uXi)!.x  
import java.net.*; \*"0wR;[K  
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public class FileSplitterFetch extends Thread { O xau
a  
4wD^?S!p  
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-  
String sURL; //File URL k+G4<qw  
long nStartPos; //File Snippet Start Position ZU@jtqq  
long nEndPos; //File Snippet End Position ~9;mZi1-  
int nThreadID; //Thread's ID *7V{yK$O|  
boolean bDownOver = false; //Downing is over ;B7|tajd  
boolean bStop = false; //Stop identical G8-d%O p  
FileAccessI fileAccessI = null; //File Access interface 5e8-?w%e  
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A"ph!* i{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ';!UJWYl  
{ "m)O13x  
this.sURL = sURL; \mit&EUh}  
this.nStartPos = nStart; C4TD@  
this.nEndPos = nEnd; Z$K%@q,10+  
nThreadID = id; "Ksd9,J\b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 tl^;iE!-  
} c+XR  
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/38Pp%
 
public void run() 62'0)Cy^  
{ J@{Bv%  
while(nStartPos < nEndPos && !bStop) =,Um;hU3r  
{ a#**96Av  
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try{ a2)*tbM9\  
URL url = new URL(sURL); t$D[,$G9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]>!_OCe&  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2YEn)A@8  
String sProperty = "bytes="+nStartPos+"-"; .kDCcnm  
httpConnection.setRequestProperty("RANGE",sProperty); ]V\g$@  
Utility.log(sProperty); bbA<Zp  
j*\MUR=  
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InputStream input = httpConnection.getInputStream(); GDe$p;#"9g  
//logResponseHead(httpConnection); >
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byte[] b = new byte[1024]; ~%q e,  
int nRead; <"9Z7" >  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P9~kN|  
{ 3CL:VwoW  
nStartPos += fileAccessI.write(b,0,nRead); 2a}_|#*  
//if(nThreadID == 1) @WUCv7U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gwk@X/q  
} ~t$VzL1  
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#f@53Pxb  
Utility.log("Thread " + nThreadID + " is over!"); 9Ky,oB  
bDownOver = true; 1x8]&  
//nPos = fileAccessI.write (b,0,nRead); :udZfA\sW  
} "q8'tN><  
catch(Exception e){e.printStackTrace ();} +d.Bf  
} D=+sD"<|  
} 7X"cu6%\  
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`8*$$JC  
//打印回应的头信息 e<pojb1Q  
public void logResponseHead(HttpURLConnection con) 5 [*jfOz  
{ Ei!z? sxzx  
for(int i=1;;i++) uDUSR+E>  
{ B$n\m854  
String header=con.getHeaderFieldKey(i); dWEx55>,1  
if(header!=null) m[rJFSpef  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -A~<IyPt  
Utility.log(header+" : "+con.getHeaderField(header)); Msi
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else n%hnL$!z  
break; vOU-bF%u  
} ekXHfA!i%  
} :2+:(^l  
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_t7A'`Dh]  
public void splitterStop() g.qp _O  
{ hHQt4 r'd  
bStop = true; Obm\h*$  
} :>u{BG;=79  
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} 6C=.8eP  
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/* bT |FJ\aC  
**FileAccess.java ]cK@
nq)  
*//文件访问(定位，写) -`JY] H  
package NetFox; scmbDaOn  
import java.io.*; `K.yE0^i  
*%.*vPJ  
~V5jjx*  
public class FileAccessI implements Serializable{ {1mD(+pJ{  
+VDB\n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 NUseYU``  
RandomAccessFile oSavedFile; b?l\QMvi  
long nPos; Cq=c'(cX  
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+=QboUN  
public FileAccessI() throws IOException ZzY6M"eUXD  
{ E6uIp^E  
this("",0); (<t)5?@%  
} >dO^pDSs  
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6mZFsB  
public FileAccessI(String sName,long nPos) throws IOException q>?oV(sF  
{ :'03*A_[  
oSavedFile = new RandomAccessFile(sName,"rw"); cVU[>gkg_  
this.nPos = nPos; d+kI
of,  
oSavedFile.seek(nPos); is,_r(
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} X#fI$9a  
b=sc2)3?  
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public synchronized int write(byte[] b,int nStart,int nLen) oVs&r?\Z  
{ `R\0g\  
int n = -1; :?zOLw?(  
try{ 1*s Lj#  
oSavedFile.write(b,nStart,nLen); @d)6LA9Ec  
n = nLen; q;U[
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} aV1(DZ83  
catch(IOException e) MQ01!Y[q_7  
{ 4GJsVA(d|  
e.printStackTrace (); N?aU<-T
n  
} +
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return n; $?7}4u,  
} \
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} H}d&>!\}F  
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/* D(y=0),  
**SiteInfoBean.java tH$Z_(5  
*/ 6HyQm?c>a  
package NetFox; N=(rl#<  
6g)21Mh#  
|<OZa;c+  
public class SiteInfoBean { *@dqAr%  
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6j0!$q^  
private String sSiteURL; //Site's URL P66>w})@  
private String sFilePath; //Saved File's Path (sZB-  
private String sFileName; //Saved File's Name yPW?%7 h  
private int nSplitter; //Count of Splited Downloading File I~Ziq10  
mN,Od?q[  
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public SiteInfoBean() 0^4Tem@  
{//nSplitter的缺省值为5 )
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//default value of nSplitter is 5 ~R3@GaL1  
this("","","",5); !pgkUzMW  
} !-[e$?-  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .(D-vkz'  
{ =MA$xz3  
sSiteURL= sURL; , j7&(V~  
sFilePath = sPath; b:oB $E  
sFileName = sName; gWRSS=8%  
this.nSplitter = nSpiltter; >Qr(#Bt)  
(Zp'|hx8o  
Fq:BRgCE  
} S'q (Qo  
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public String getSSiteURL() b8(94t|;U  
{ oJEind>8O  
return sSiteURL; JS}iNS'X  
} D >$9(  
46sV\In>?  
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public void setSSiteURL(String value) 3nMXfh/  
{ w!7Hl9BW  
sSiteURL = value; Z
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} ry0P\wY}  
!IF#L0z  
}9=VhC%J  
public String getSFilePath() Bg{"{poy  
{ -Z9e}$q$,  
return sFilePath; JHBX'1GQa  
} sSU p7V  
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public void setSFilePath(String value) h{#Hwp  
{ l!
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sFilePath = value; /3{jeU.k  
} .*+%-%CbP  
{94qsVxQZ  
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public String getSFileName() eh`n?C  
{ F[5[@y  
return sFileName; eT0Yp  
} c"~+Y2]tL  
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public void setSFileName(String value) S}WQ~e  
{ {oOzXc
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sFileName = value; hV_bm@f/y  
} %|Sh|\6A!  
lcO;3CrJ!  
k  <SFl  
public int getNSplitter() R<}UT  
{ x%@n$4wk7  
return nSplitter; 3@7IY4>o  
} <2^XKaS`  
z$C}V/Ey  
9\y\{DHd  
public void setNSplitter(int nCount) |1!RvW:[!  
{ [TRHcz n  
nSplitter = nCount; <2{g[le  
} ROb2g|YXG  
} kyR=U`OW  
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/* <a_ytSoG1  
**Utility.java I54`}Npp  
*/ 4Cm+xAXG  
package NetFox; Vh=10Et  
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J%r$jpd'  
public class Utility { 3M~*4  
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public Utility() q.I  
{ ?P
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fRlO.!0(  
} jxeZ,w o  
*e/8
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//线程睡眠 |&wwH&<[z  
public static void sleep(int nSecond) {_[\k^98>  
{ t:$^iUrx  
try{ Ct@OS227x  
Thread.sleep(nSecond); % XvJJ  
} ;fiH=_{us  
catch(Exception e) 9IfeaoZZ4q  
{ so=Ux2  
e.printStackTrace (); KcPI,.4{  
} ny++U;qi  
} NRIp@PIF:"  
Z@f4=  
//日志 ';,Rq9-'  
public static void log(String sMsg) ,
;%
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{ uz U2)n3y  
System.err.println(sMsg); jc0Trs{Jf  
} cI#! Y  
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zfGS=@e]G  
public static void log(int sMsg) RZ+SOZs7H  
{ {PBm dX  
System.err.println(sMsg); D^dos`L0b  
} #cGn5c}  
} S29k IJ  
o!$O+%4  
X7."hGu@  
/* i`st'\I  
**TestMethod.java Z~[EZgIg  
*/ $-4 Zi  
package NetFox; A*x3O%zH  
`bAOhaB,/  
25R6>CXsi  
public class TestMethod { #]SiS2lM#  
J!+)
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public TestMethod() YZ\a#s,0  
{ ///xx/weblogic60b2_win.exe 4;;K1< 1  
try{ P[q 'Y^\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N$I@]PL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BK*Bw,KQ<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .G/>X%
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fileFetch.start(); <0sT  
} GI.=\s  
catch(Exception e){e.printStackTrace ();} B QxU~s  
.=`r?#0  
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} v$JhC'  
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public static void main(String[] args) |i
~Ab!*8n  
{ DuvI2ZWP]  
new TestMethod(); (?W[#.=7  
} q\uzmOh  
} #t8{z~t3  
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