http断点续传简单实现（java)

/* >&K1+FSmyJ  
**SiteFileFetch.java k<xiP@b{y  
*/ $a|D
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package NetFox; \;w+_<zE5{  
import java.io.*; #!wL0p  
import java.net.*; o|\0IG(\  
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\de824  
public class SiteFileFetch extends Thread { ?UAB}CjY  
IfHB+H   
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SiteInfoBean siteInfoBean = null; //文件信息Bean ,LjB%f[  
long[] nStartPos; //开始位置 xP<cF  
long[] nEndPos; //结束位置 {/]Ks8`Dm  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 w$~|/UrLf  
long nFileLength; //文件长度 $`:/OA<.  
boolean bFirst = true; //是否第一次取文件 gf`uC0  
boolean bStop = false; //停止标志 p&wXRI  
File tmpFile; //文件下载的临时信息 S0V%JY;Gv  
DataOutputStream output; //输出到文件的输出流 H\tz"<*``  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "]}+QK_  
public SiteFileFetch(SiteInfoBean bean) throws IOException -ec~~95  
{ Las
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siteInfoBean = bean; B;A^5~b  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ][8ZeM9&p  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =;.#Bds  
if(tmpFile.exists ()) eW$G1h:  
{ X4emhB  
bFirst = false; ,Mf@I5?  
read_nPos(); [gZd$9a  
} 9Ny{2m=Ye  
else \~4uEk"]  
{ V#;6<H"  
nStartPos = new long[bean.getNSplitter()]; H R$\jJ  
nEndPos = new long[bean.getNSplitter()]; &P>wIbE  
} cyq]-B  
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} C<CE!|sfr  
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@,i_ KN6C  
public void run() o/EA%q1  
{ 8UArl
3  
//获得文件长度 FyN@mX  
//分割文件 *bu/Ko]  
//实例FileSplitterFetch xXl^\?HC  
//启动FileSplitterFetch线程 CybHr#LBc  
//等待子线程返回 K9co_n_L  
try{ K29]B~0%E  
if(bFirst) BJDe1W3;'  
{ ^|DI9G(Bs  
nFileLength = getFileSize(); ($^XF:#5  
if(nFileLength == -1) RG=!,#X  
{ W/U&w.$  
System.err.println("File Length is not known!"); 7Wg0-{yK4  
} kd9rvy0oK  
else if(nFileLength == -2) 0eY$K7 U  
{ *V(TNLIh;  
System.err.println("File is not access!"); lJ!+n<K+  
} {uEu ^6a5  
else J2_DP  
{ :UmY|=v?t  
for(int i=0;i<nStartPos.length;i++) ye1kI~LO(  
{ =/MAKi}g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nfck3h  
} iQpKcBx  
for(int i=0;i<nEndPos.length-1;i++) CMa~BOt#  
{ E 5PefD\m  
nEndPos = nStartPos[i+1]; L-[<C/`;t  
} ^y"Rdv  
nEndPos[nEndPos.length-1] = nFileLength; (l :;p&[  
} _|.q?;C]$  
} n0#HPI"  
;wCp j9hir  
?#^(QR|/  
//启动子线程 :`6E{yfM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; w^09|k  
for(int i=0;i<nStartPos.length;i++) WZaOw w  
{ Jq)!)={  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;Dg8>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ETe,RY  
nStartPos,nEndPos,i); 3X,9K23T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EeWCy5W  
fileSplitterFetch.start(); xfw)0S  
} 6bCC6G  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |S#)[83*3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); O G#By6O  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |Euf:yWY  
nEndPos = " + nFileLength); M
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// fileSplitterFetch[nPos.length-1].start(); eS9/-Y  
'Syq!=,  
rgheq<B:  
//等待子线程结束 weC$\st:D  
//int count = 0; U]Q2EL\%  
//是否结束while循环 {zhN>n_  
boolean breakWhile = false; (</cu$w>H)  
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while(!bStop) Jla ;^X  
{ :i+Tf~k{  
write_nPos(); Kr`Cr5v  
Utility.sleep(500); [aX'eMq
 
breakWhile = true; p%5RE%u  
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*b9=&:pU(  
for(int i=0;i<nStartPos.length;i++) jLc4D'  
{ hh`7b,+ 4  
if(!fileSplitterFetch.bDownOver) ?fcQd6-}  
{ zZDa71>  
breakWhile = false; <T JUKznO  
break; \M1-  
} aB~?Y+m  
} ;,n{6`  
if(breakWhile) j.X3SQb4G  
break; 1QXv}36#3n  
'cJHOd  

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//count++; C0;c'4(  
//if(count>4) zuR!,-W  
// siteStop(); *KSQ^.sYh  
} ^'r/;(ZF*/  
MDa 4U@Q  
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System.err.println("文件下载结束！"); ($&i\e31N  
} <hgt{b4  
catch(Exception e){e.printStackTrace ();} iqURlI);P  
} "<x%kD  
^0ZabR'  
<)+9PV<w  
//获得文件长度 D_@WB.eL  
public long getFileSize() AjB-&Z  
{ -4{sr| lm  
int nFileLength = -1; +s.r!?49+  
try{ b_@MoL@A!  
URL url = new URL(siteInfoBean.getSSiteURL()); dM8`!~#&PI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w$4fS
 
httpConnection.setRequestProperty("User-Agent","NetFox"); lpLjfHr  
Mp9wYM*  
_!kL7qJ"  
int responseCode=httpConnection.getResponseCode(); %{g<{\@4(;  
if(responseCode>=400) Dsc{- <v  
{ 1foy.3g-  
processErrorCode(responseCode); .<j\"X(  
return -2; //-2 represent access is error C]K|;VQ  
} lO>w|=<  
z/(^E8F  
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String sHeader; Fu:VRul=5$  
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9m MPkgc  
for(int i=1;;i++) ^2}0lP|  
{ PJLSDIeN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); DYkNP:+  
//Utility.log(in.readLine()); ^@e4mO  
sHeader=httpConnection.getHeaderFieldKey(i); s0 hD;`cm  
if(sHeader!=null) pTPWToKh  
{ I5PI;t+  
if(sHeader.equals("Content-Length")) -Zd0[& ']  
{ 3 4CqLPg8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {(#Dou  
break; H'Q4IRT  
} >QV=q`I  
} LO0<=4iN(  
else ^c" wgRHc<  
break; `Et)@{iP  
} <m:8%]%M6  
} ?bu-6pkx]  
catch(IOException e){e.printStackTrace ();} d-w#\ ^  
catch(Exception e){e.printStackTrace ();} VJ;4~WgBz  
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Utility.log(nFileLength); u*0Ck*pZ  
FB3C'!'<)  
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return nFileLength; `''\FPhh  
} ," ~ew ,  
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]wCg'EUB  
//保存下载信息（文件指针位置） f]N2(eM  
private void write_nPos() kKwb)i  
{ zI77#AUM  
try{ 8TIc;'b
RM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); d[(KgX9  
output.writeInt(nStartPos.length); N0h
* |  
for(int i=0;i<nStartPos.length;i++) aj;OG^(!2_  
{ F@ lJk|*_  
// output.writeLong(nPos); R@Ch3l@  
output.writeLong(fileSplitterFetch.nStartPos); O+hN?/>v  
output.writeLong(fileSplitterFetch.nEndPos); ^Rriu $\  
} H7!j5^  
output.close(); A7,TM&  
} R,?
7|x  
catch(IOException e){e.printStackTrace ();} qELy'\  
catch(Exception e){e.printStackTrace ();} |9cJO@  
} }_m/3*x_  
]Gm"U!h*  
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//读取保存的下载信息（文件指针位置） ikd~k>F  
private void read_nPos() Oo<L~7B  
{ 7kJ =C  
try{ D0NSzCHx  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); HC4qP9Gs  
int nCount = input.readInt();
d*;wHA,}F  
nStartPos = new long[nCount]; MBZ/Pzl~  
nEndPos = new long[nCount]; *mH+
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for(int i=0;i<nStartPos.length;i++) 5lehASBz  
{ Fy_D
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nStartPos = input.readLong(); ;^VLx)q  
nEndPos = input.readLong(); vqDd][n  
} :(gZ\q">k  
input.close(); &0A^_Z .nA  
} ;s m )f  
catch(IOException e){e.printStackTrace ();} J eCKnt=  
catch(Exception e){e.printStackTrace ();} N
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} n@IpO i$Q  
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private void processErrorCode(int nErrorCode) NVqJN$z  
{ ^5n"L29V  
System.err.println("Error Code : " + nErrorCode); }cUq1r-bW  
} Te&F2`vo  
fHK`u'  
t;g=@o9YA  
//停止文件下载 <49Gsm&0  
public void siteStop() I29aj
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{ S[g{ )p)  
bStop = true; imGg3'  
for(int i=0;i<nStartPos.length;i++) V?x&.C2Z  
fileSplitterFetch.splitterStop(); K]5@bm  
;la sk4
|  
rt-^?2c?  
} mOm_a9ML  
} Ei@w*.3P<  
//负责部分文件的抓取 n1D,0+N=  
**FileSplitterFetch.java ?Ybgzb  
*/ f'501MJu  
package NetFox; T \d
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oT9dMhx8  
90ZMO7_  
import java.io.*; wQ!C9Gp3e  
import java.net.*; 9p|;Hh:  
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X
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public class FileSplitterFetch extends Thread { |^: A,%>  
l\+^.ezD  
R'M=`33M  
String sURL; //File URL Y|%s =0M  
long nStartPos; //File Snippet Start Position 3.[ fTrzJ  
long nEndPos; //File Snippet End Position J0xV\O !e  
int nThreadID; //Thread's ID %NH#8#';2  
boolean bDownOver = false; //Downing is over /Z':wu\  
boolean bStop = false; //Stop identical 3QNu7oo  
FileAccessI fileAccessI = null; //File Access interface |"t)#BUtL  
V $'~2v{_  
hsYS<]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :xqhPr]e  
{ M.b1=Y  
this.sURL = sURL; ~MuD`a7#G  
this.nStartPos = nStart; s#phs`v  
this.nEndPos = nEnd; t]dtBt].:  
nThreadID = id; A5U//y![{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ollJ#i9  
} O{YT6&.S0
 
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public void run() V5ve  
{ _[J @w.l(  
while(nStartPos < nEndPos && !bStop) 'IVNqfC)u  
{ u`K)dH,  
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try{ 7sgK+ ip  
URL url = new URL(sURL); wlSl ~A/s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zVeQKN
9^Z  
httpConnection.setRequestProperty("User-Agent","NetFox");  Xaz`L  
String sProperty = "bytes="+nStartPos+"-"; ,gag_o{*a  
httpConnection.setRequestProperty("RANGE",sProperty); )Q:.1H
gl  
Utility.log(sProperty); e u{  
L$T23*9XY  
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InputStream input = httpConnection.getInputStream(); 4gyC?#Ed
e  
//logResponseHead(httpConnection); c:[z({
`  
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byte[] b = new byte[1024]; hh%fmc  
int nRead; k 5~#_D>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [9}D
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{ nw.,`M,N  
nStartPos += fileAccessI.write(b,0,nRead); '+%<\.$  
//if(nThreadID == 1) G&2UXr3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q$#5>5&  
} E[IjeJB5  
h\]D:S  
3u&>r-V6Fn  
Utility.log("Thread " + nThreadID + " is over!"); *?l-:bc]  
bDownOver = true; 397IbZ\  
//nPos = fileAccessI.write (b,0,nRead); l*l?aI  
} >VnBWa<j3  
catch(Exception e){e.printStackTrace ();} B<V8:vOam  
} KM'*+.I  
} VaV(+X  
|+-D@22y  
/"Z6\T9  
//打印回应的头信息 __B`0t  
public void logResponseHead(HttpURLConnection con)  Rix|LKk{  
{ 2b&&3u8  
for(int i=1;;i++) 9n\b
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{ u;@~P  
String header=con.getHeaderFieldKey(i); s2IjZF{  
if(header!=null) dq6|m }g{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D]P_tJI  
Utility.log(header+" : "+con.getHeaderField(header)); 8ch^e[U`  
else j@ehcK9|  
break; `<cnb!]  
} [wLK*9@&  
} S)n+E\c  
9Q*T'+V  
DK6^\k][V  
public void splitterStop() xAZ-_}'tW  
{  _klT  
bStop = true; e-@.+f2CC  
} sWG_MEbu  
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} [5"F=tT7WP  
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F"G]afI9+  
/* fV>12ici  
**FileAccess.java Z?@oe-mz  
*//文件访问(定位，写) :gwM$2vv  
package NetFox; VKZZTFmV2)  
import java.io.*; vq?aFX9F  
D#8uj=/%  
DI>SW%)>  
public class FileAccessI implements Serializable{ d?9b6k?  
/Wx({N'
h$  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Kw/7X[|'G  
RandomAccessFile oSavedFile; %}`zq8Q
;  
long nPos; _MmSi4]yd  
[yyL2=7  
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public FileAccessI() throws IOException Dr_ (u<[  
{ zJMm=Mw^  
this("",0); >QA;02  
} ]-2Q0wTj  
ukInS:7  
#a$k3C  
public FileAccessI(String sName,long nPos) throws IOException lx)Bj6  
{ Q 1:7 9  
oSavedFile = new RandomAccessFile(sName,"rw"); F5+)=P#  
this.nPos = nPos; (q 0wV3Qv  
oSavedFile.seek(nPos); rBLcj;,
 
} CAJ]@P#Xj+  
Y3n6y+Uzk  
?l/$cO  
public synchronized int write(byte[] b,int nStart,int nLen) X+$IaLfCxD  
{ O]1aez[  
int n = -1; -Uj3?W  
try{ x("V+y*  
oSavedFile.write(b,nStart,nLen); 1SwKd*aRR?  
n = nLen; phc9esz  
} K}feS(Ji  
catch(IOException e) x^959QO~  
{ ?c6`p3p3L  
e.printStackTrace (); \F'tl{'\@  
} /=i+7^  
/>13?o#  
Lk>GEi|  
return n; a49xf^{1"i  
} @ )2<$d  
"<Q,|
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~\yk{1S  
} Ia%S=xU{=  
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/* A?;KfVq  
**SiteInfoBean.java /4M~ 6LT`  
*/ vxt<}h5J/!  
package NetFox; +#LD@)G  
j` 5K7~hv  
"
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public class SiteInfoBean { Er!s\(h  
Rch?@O#J  
)1ct%rue  
private String sSiteURL; //Site's URL \-Ipa59U  
private String sFilePath; //Saved File's Path lmbC2\GT  
private String sFileName; //Saved File's Name T[\?fSP  
private int nSplitter; //Count of Splited Downloading File a j13cC$  
@ |^;d  
Ni Y.OwKr  
public SiteInfoBean() %h^ f?.(:  
{//nSplitter的缺省值为5 NN"!kuM  
//default value of nSplitter is 5 N_Q\+x}zq  
this("","","",5); \ 0J&^C  
} JIh:IR(ta  
RbN# dI'  
9J(jbJ7p  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B4kJ 7Pdny  
{ tvEf-z  
sSiteURL= sURL; {IG5qi?/E)  
sFilePath = sPath; 1c19$KHu  
sFileName = sName; 8;q2W F{AX  
this.nSplitter = nSpiltter; C9Xj)5k@R  
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O
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} '.5_
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7dq*e4z)  
+m]Kj3-z@  
public String getSSiteURL() gu|cQ2xV  
{ Qs #7<NQ  
return sSiteURL; wxW\L!@  
} (-bLP
 
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2J1YrHj3  
public void setSSiteURL(String value) /xh/M@G3  
{ 1 [D,Mu%E  
sSiteURL = value; 1@6FV x  
} FJH'!P\  
2)^gd  
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public String getSFilePath() p`mNy o'  
{ TChKm-x  
return sFilePath; tO8<N'TD  
} /5&'U!:+  
SMIr@*R  
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public void setSFilePath(String value) 12y+g5b  
{ :J~sz)n4  
sFilePath = value; D)){"Q!b  
} uNXKUJ V0  
E5`KUMZkq  
$9PscubM4  
public String getSFileName() gzd)7np B2  
{ ["}Yp  
return sFileName; [ m#|[%  
} v
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^wTod\y  
s;!Tz)  
public void setSFileName(String value) T$vDw|KSVP  
{ M_Z(+k{Gy  
sFileName = value; 8TV "9{ n  
} ?o883!&v  
)4CF*>*6V  
TD6MP9L  
public int getNSplitter() P(Wr[lH\y  
{ U%T{~f  
return nSplitter; bS"zp6Di  
} ~Jlo>  
kHx6]<  
Bq*aP*jv  
public void setNSplitter(int nCount) ,o68xfdZVW  
{ p&Ev"xhs  
nSplitter = nCount; jTE~^  
} alz2F.%Y  
} ReZ&SNJ  
ZgH(,g,TU  
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/* dVe  
**Utility.java r.#"he_6!.  
*/ _+NM<o#A  
package NetFox; YfZ96C[a  
f>kW\uC  
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public class Utility { CF0i72ul5  
8-uRn38  
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public Utility() b@?pofZ`k  
{ vzPuk|q3  
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p0Ra`*f  
} p"k[ac{  
tShyG!b  
//线程睡眠 dp~] Wx  
public static void sleep(int nSecond) m%[`NP (  
{ zM+eb| >cr  
try{ '%\FT-{  
Thread.sleep(nSecond); p"ElO,\  
} ZCuLgCP?Z  
catch(Exception e) e=#'rDm  
{ ;fl3'.S[  
e.printStackTrace (); 2uy<wJE>  
} ocDAg<wo  
} ]46#u=y~3  
| l
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//日志 #[ZNiaWT  
public static void log(String sMsg) NpN-''B\  
{ >2[nTfS  
System.err.println(sMsg); Vb$
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} A[6D40o  
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W
v4o:_}  
public static void log(int sMsg) ]UFbG40Zo  
{ WO<a^g {  
System.err.println(sMsg); SdM@7%UK  
} 71(C@/J  
} ?@LqrKj11  
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.]D7Il  
/* #Rx|oSc}  
**TestMethod.java iwS55o  
*/ |z%:{  
package NetFox; }VI}O{  
j
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2ms@CQy(00  
public class TestMethod { zc#$hIi  
DSX.84  
6l,oL'$}P1  
public TestMethod() 
.QVZ!  
{ ///xx/weblogic60b2_win.exe N_^s;Qj  
try{ n)xLEx,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); p81Vt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >jH%n(TcC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6(as.U>K  
fileFetch.start(); ?Ja&LNI9S  
} E Zh.*u@^r  
catch(Exception e){e.printStackTrace ();} #
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G}8Zkz@+  
} ~P;KO40K  
P<s0f:".  
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public static void main(String[] args)  SG@-b(  
{ 2T >K!jS  
new TestMethod(); H4{CiZ  
} <]e0TU?bk  
} 8AgKK=C=  
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