http断点续传简单实现（java)

/* %#7Yr(&
 
**SiteFileFetch.java |]y]K%  
*/ :A9G>qg  
package NetFox; gP:
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import java.io.*; kdcr*7w  
import java.net.*; ]lV\D8#  
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public class SiteFileFetch extends Thread { >,wm-4&E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ( E;!.=%  
long[] nStartPos; //开始位置 ~H`~&?  
long[] nEndPos; //结束位置 3Uw}!>`%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {a;my"ly  
long nFileLength; //文件长度 JI##l:,7r  
boolean bFirst = true; //是否第一次取文件 R-5EztmLae  
boolean bStop = false; //停止标志 9Kf# jZ  
File tmpFile; //文件下载的临时信息 {]ie|>'=C  
DataOutputStream output; //输出到文件的输出流 J=Q?_$xb}  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &]~Vft l  
public SiteFileFetch(SiteInfoBean bean) throws IOException qn=~4rg]R  
{ I*hCIy#;  
siteInfoBean = bean; +X#JCLD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Kw_> X&GcJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $ReoIU^<  
if(tmpFile.exists ()) tn>z%6;&Z  
{ !(QDhnx}9c  
bFirst = false; #[=%+*Q  
read_nPos(); w eu3c`-a  
} 9=D09@A%e  
else X} <p|P+  
{ >,;, 6|S  
nStartPos = new long[bean.getNSplitter()]; F-0|&0  
nEndPos = new long[bean.getNSplitter()]; /a@gE^TM  
} jG~zpZh  
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} 98O0M#|d  
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public void run() a8$gXX-2  
{ R{N9'2l:  
//获得文件长度 w=Cqv~  
//分割文件 `q":i>FP2  
//实例FileSplitterFetch C5k\RS9  
//启动FileSplitterFetch线程 1VRexp  
//等待子线程返回 />FgDIO  
try{ *?dw`j_b >  
if(bFirst) :s(vn Ie^  
{ 1FC' iGI  
nFileLength = getFileSize(); N3O~_=/v?  
if(nFileLength == -1) UM[<v9NWE  
{ 0{0BL@H  
System.err.println("File Length is not known!"); ^6c=[N$aW  
} Pi7IBz  
else if(nFileLength == -2) bvpP/LeY  
{ (x"TM),Q  
System.err.println("File is not access!"); x.J% c[Q8  
} 4Og&w]  
else )3 C~kmN7  
{ JrZ"AId2  
for(int i=0;i<nStartPos.length;i++) >U?U;i  
{ rwYlg:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %UV'HcO/gp  
} BM6 J  
for(int i=0;i<nEndPos.length-1;i++) AiMD"7 )c  
{  0C3s  
nEndPos = nStartPos[i+1]; B-EVo&.  
} b d!|/Lk  
nEndPos[nEndPos.length-1] = nFileLength; 0qND2_  
} k#*tf:
R  
} q].n1w[  
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~D[5AXV`^  
//启动子线程 ? dD<KCbP,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5yC$G{yV  
for(int i=0;i<nStartPos.length;i++) HZ>8@AVa\  
{ WrzyBG_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i]sz*\P~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =[X..<bW9:  
nStartPos,nEndPos,i); Yr7%C  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iPnu *29  
fileSplitterFetch.start(); EUxkYl  
} 4O~E4" ]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )}{V#,xz@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l,(Mm,3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `/+%mKlC|[  
nEndPos = " + nFileLength); 2`|1 !x  
// fileSplitterFetch[nPos.length-1].start(); ,sU#{.(  
">?ocJ\9  
?z "fp$  
//等待子线程结束 Ws_RS%  
//int count = 0; @%8Xa7+  
//是否结束while循环 g(9\r  
boolean breakWhile = false; kB`t_`7f  
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while(!bStop) / /ty]j  
{
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write_nPos(); ;a]Lxx;-  
Utility.sleep(500); }
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breakWhile = true; .Fdqn?c|+  
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for(int i=0;i<nStartPos.length;i++) UD0via  
{ [#}A]1N  
if(!fileSplitterFetch.bDownOver) }4 p3m]  
{ Ib$*w)4:  
breakWhile = false; Y;JPr  
break; }YPW@g  
} 1Tn0$+$.4  
} S}0W<H P  
if(breakWhile) Yn0l}=, n  
break; q;Y9_5S  
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pH#*:v!)  
//count++; Y+ZQN>  
//if(count>4) p^=>N9  
// siteStop(); n9qO;X4&  
} cyR K&J  
32DSZ0  
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System.err.println("文件下载结束！"); ~S5wfx&  
} `vkNp8|  
catch(Exception e){e.printStackTrace ();} aFZu5-=x  
} v^Vr^!3  
XET'XJWF%  
2<Vw :+,  
//获得文件长度 ;B8#Nf  
public long getFileSize() >lD*:#o  
{ )kMA_\$,  
int nFileLength = -1; 
gnAM}  
try{ sn|q EH  
URL url = new URL(siteInfoBean.getSSiteURL()); qNhV zx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a!`b`r-4  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1KH]l336D"  
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int responseCode=httpConnection.getResponseCode(); SAuZWA4g[  
if(responseCode>=400) 76Drhh(  
{ tb%u<jY  
processErrorCode(responseCode); uxbDRlOS  
return -2; //-2 represent access is error |*~=w J_  
} !OM P]  
.d\<}\zZ7J  
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String sHeader; ul{u^ j  
buIy+  
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for(int i=1;;i++) ,I(PDlvtM  
{ ZcTxE]Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #g ;][  
//Utility.log(in.readLine()); NPN*k].  
sHeader=httpConnection.getHeaderFieldKey(i); o6H\JCne  
if(sHeader!=null) c5>'1L  
{ ]6W;~w%  
if(sHeader.equals("Content-Length")) F vJJpPS  
{ $!+t2P@d.5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Fv[. %tW  
break; <tT*.n
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} -3YsrcJi  
} |sM#nhxK  
else (9;qV:0`  
break; Gi<ik~  
} 6 (:^>@  
} X>i`z  
catch(IOException e){e.printStackTrace ();} Ch`nDIne  
catch(Exception e){e.printStackTrace ();} 0YMmWxV  
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Utility.log(nFileLength); ,bv?c@  
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return nFileLength; ,zCrix 3  
} u )'l|Y  
AR<'Airi:  
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//保存下载信息（文件指针位置） @J[l^o9  
private void write_nPos() 'IaI7on  
{ 9Y9pKTU  
try{ E8-8E2i,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /a
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output.writeInt(nStartPos.length); :+1S+w  
for(int i=0;i<nStartPos.length;i++) RETq S  
{ $gYy3y  
// output.writeLong(nPos); mY+.(N7m  
output.writeLong(fileSplitterFetch.nStartPos); 1' #%UA  
output.writeLong(fileSplitterFetch.nEndPos); PI"&-lXI-m  
} =~Ac=j!q  
output.close(); o=!3=2@dh  
} .3(=UQ  
catch(IOException e){e.printStackTrace ();} >E;&SX  
catch(Exception e){e.printStackTrace ();} =y3gnb6  
} w|6;Pf~1y)  
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>R5qhVYFb  
//读取保存的下载信息（文件指针位置） 9]Q\Pr\Ub$  
private void read_nPos() QOG S` fh  
{ 7\'ow|)}v  
try{ IN? A`A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4<`x*8` ,  
int nCount = input.readInt(); fo"dX4%}  
nStartPos = new long[nCount]; _IAvFJI  
nEndPos = new long[nCount]; S9sFC!s1g  
for(int i=0;i<nStartPos.length;i++) `r; .  
{ "s']@Qv  
nStartPos = input.readLong(); +C~,q{u  
nEndPos = input.readLong(); gnS0$kCJ:  
} &} b'cO  
input.close(); oR.KtS$uh  
} d2w;d&2S  
catch(IOException e){e.printStackTrace ();} i8$tId  
catch(Exception e){e.printStackTrace ();} w!Nt
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} ~jd:3ip+!  
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private void processErrorCode(int nErrorCode) U=<E,tM  
{ MC5M><5\  
System.err.println("Error Code : " + nErrorCode); /jI>=:z  
} *iSsGb\M%  
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//停止文件下载 =1o
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public void siteStop() ]Y|Y?  
{ &`7tX.iMlh  
bStop = true; RRaGc )B  
for(int i=0;i<nStartPos.length;i++) {nH. _  
fileSplitterFetch.splitterStop(); s[:e '#^  
-\;x>=#B  
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} dQ*3s>B[  
} U8?%Dq%i  
//负责部分文件的抓取 W,zlR5+Jk  
**FileSplitterFetch.java cdL$T6y  
*/ <Bc J;X/  
package NetFox; mw<LNnT{8  
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import java.io.*; &6/# O  
import java.net.*; xzdqE  
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public class FileSplitterFetch extends Thread { ^s25z=^t  
9:^SnHAa  
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String sURL; //File URL [((P,v*  
long nStartPos; //File Snippet Start Position [`P+{ R  
long nEndPos; //File Snippet End Position (o_wv  
int nThreadID; //Thread's ID XW6>;:4k  
boolean bDownOver = false; //Downing is over PTe8,
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boolean bStop = false; //Stop identical &?(
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FileAccessI fileAccessI = null; //File Access interface YPAMf&jEF  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException d$<HMs:o@  
{ C?Dztkz  
this.sURL = sURL; ~={8b  
this.nStartPos = nStart; ![os5H.b#q  
this.nEndPos = nEnd; R9gK>}>Y  
nThreadID = id; e7/ b@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k<uC[)_  
} sfez0Uqe.~  
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' jFSv|g+0  
public void run() '+BcPB?E  
{ wm|{@z  
while(nStartPos < nEndPos && !bStop) }<w/2<T[  
{ rmc0dm&l]  
"Ko^m(`  
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try{ > TG:}H(J  
URL url = new URL(sURL); HT/zcd)}#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,Z*?"
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httpConnection.setRequestProperty("User-Agent","NetFox"); f.0~HnNg1  
String sProperty = "bytes="+nStartPos+"-"; mM"!=' z  
httpConnection.setRequestProperty("RANGE",sProperty); `,ZsKxI  
Utility.log(sProperty); Hep]jxp+  
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InputStream input = httpConnection.getInputStream(); ?4wS/_C/
 
//logResponseHead(httpConnection); NKd!i09`  
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byte[] b = new byte[1024]; uJ,>Y# ?  
int nRead; F+R4nFA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Oqeoh<y!\  
{ g$eb@0$  
nStartPos += fileAccessI.write(b,0,nRead); ZRO   
//if(nThreadID == 1) 7Zp'}Om<I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \I; lgz2  
} _*B]yz6z
 
17[7)M88  
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Utility.log("Thread " + nThreadID + " is over!"); XRVE8v+  
bDownOver = true; /02|b}{  
//nPos = fileAccessI.write (b,0,nRead); SnVIV%  
} #(-V^T  
catch(Exception e){e.printStackTrace ();} %"V Y)  
} pZz?c/h-  
} Qjh5m5e  
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&;5QB  
//打印回应的头信息 iZGc'y  
public void logResponseHead(HttpURLConnection con) }R*[7V9"  
{ @#Jc!p7)  
for(int i=1;;i++) r-'(_t~FT  
{ Iq.*2aff+  
String header=con.getHeaderFieldKey(i); Z8tQ#Pu{  
if(header!=null) TTpK8cC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #R<4K0Xan  
Utility.log(header+" : "+con.getHeaderField(header)); a5C%OI<  
else l)GV&V  
break; Ee;&;Q,O.z  
} D%kY  
} P31}O2 Nh  
MrEyN8X  
 Ko9"mHNB  
public void splitterStop() ]N!382  
{ *@|d7aiO  
bStop = true; IQxY]0\uf6  
} %M^X>S\%  
#DpDmMP9R3  
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} Am&/K\O  
{\ vj":  
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/* =8[4gM+  
**FileAccess.java L,V\g^4$K  
*//文件访问(定位，写) <Hl.MS  
package NetFox; v.H00}[.  
import java.io.*; '0D2e  
}Wjb0V  
cx M=#Go  
public class FileAccessI implements Serializable{ vBAds  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :$j6  
RandomAccessFile oSavedFile; / 2>\Z(  
long nPos; znv2
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public FileAccessI() throws IOException X(kyu,w  
{ O0Y/y2d  
this("",0); E$]7w4,n  
} ?it49  
4^(u6tX5|+  
nBv|5$w:  
public FileAccessI(String sName,long nPos) throws IOException F-g(Hk|v  
{ qwJe
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oSavedFile = new RandomAccessFile(sName,"rw"); H/'tSb  
this.nPos = nPos; >7. $=y8b  
oSavedFile.seek(nPos); ;*ebq'D([  
} U,S&"`a  
:{?8rA5  
C5m6{Oo+-  
public synchronized int write(byte[] b,int nStart,int nLen) *#{[9d  
{ kb{h`  
int n = -1; 67Rsd2   
try{ % FW__SN$c  
oSavedFile.write(b,nStart,nLen); rld4uy}m  
n = nLen; X'4e)E3*O  
} ,":_=Tf.  
catch(IOException e) $ KQ7S>T  
{ iHhoNv`MR  
e.printStackTrace (); [4B.;MS(  
} u6h"=l{  
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return n; 1c_qNI;:p  
} Ub(zwR;  
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} Ag QR"Nu6  
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/* g &~T X  
**SiteInfoBean.java }3 NGMGu$  
*/ ]X/1u"  
package NetFox; (NrH)+)J!a  
IBm&a^  
:c%vl$  
public class SiteInfoBean { //*>p  
_D7MJT  
}2 zJ8A9-  
private String sSiteURL; //Site's URL #]bWE$sU<  
private String sFilePath; //Saved File's Path zS*GYE(l^  
private String sFileName; //Saved File's Name (wLzkV/6  
private int nSplitter; //Count of Splited Downloading File }<`Mn34@  
0Pw?@uV  
=+`I%>wc  
public SiteInfoBean() {<%zcNKl^L  
{//nSplitter的缺省值为5  4KF 1vw  
//default value of nSplitter is 5 99
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this("","","",5); ?rC^@)  
} jz(}P8  
NMb`d0;(  
A;Rr#q<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "Wd?U[[  
{ C'3/B)u}l  
sSiteURL= sURL; tAH,3Sz( /  
sFilePath = sPath; N6H/J_:  
sFileName = sName; NFTEp0eP  
this.nSplitter = nSpiltter; :9!?${4R  
]p>6r*/nw  
6'd=% V  
} R4=n">>Q  
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public String getSSiteURL() |Q2H^dU'rQ  
{ &z;F'>"  
return sSiteURL; oZ;u>MeZ  
} O.4ty)*  
#UGm/4C  
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public void setSSiteURL(String value) vG9A'R'P  
{ ,W"Q)cL  
sSiteURL = value; uTY5.8  
} >AIkkQT  
]v96Q/a  
@4dB$QF`&  
public String getSFilePath() odAeBQy  
{ QU0K'4Yx5j  
return sFilePath; 6+HpN"?e  
} KrN#>do&<  
w8i"-SE  
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public void setSFilePath(String value) >(+g:p  
{ Qe<DX"  
sFilePath = value; V4p4m@z^u  
} hKP!;R  
2lPj%i 5  
16=tHo8|  
public String getSFileName() Z"rrbN1  
{ G\3@QgyQ  
return sFileName; |,rIB
 
} Ht#5;c2/  
En%PIkxeR  
]h8[b9$<")  
public void setSFileName(String value) 7Z;bUMYtx  
{ F/;uN5{o  
sFileName = value; xJ H]>#XJ  
} ><9E^ k0.  
Et{4*+A  
afY~Y?PJ<  
public int getNSplitter() sE7!U|  
{ L ;5uB2  
return nSplitter; R /J@XP  
} F.ml]k&(m  
tEP~`$9  
;QbMVY  
public void setNSplitter(int nCount) h;105$E1  
{ bp Q/#\Z  
nSplitter = nCount; >]uV  
} |~vo  
} 1?s]nU  
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/* t~m >\(&  
**Utility.java xu[6h?u(h8  
*/ mEsOYIu{  
package NetFox; Nb/W+& y  
f,{O%*PUA  
h ,;f6  
public class Utility { ?h)Z ;,}  
v:0.  
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public Utility() k fS44NV  
{ 0 =#)-n  
h6c0BmS{1  
t3%[C;@wB  
} FTvFtdY  
j?sq i9#  
//线程睡眠 .: ~);9kj  
public static void sleep(int nSecond) RL0,QC)e#@  
{ GZgu1YR
 
try{ tVJ}NI #  
Thread.sleep(nSecond); D0Cs g39  
} 2t'^  
catch(Exception e) &wc%mQV  
{ 8z\v|-%Z  
e.printStackTrace (); \d~sU,L;]  
} Hbz>D5$  
} ^gx`@^su  
/7Z5_q_  
//日志 }S84^2
J_  
public static void log(String sMsg) zFVNb  
{ lt 74`9,f  
System.err.println(sMsg); ()L[l@m  
} [:Kl0m7  
Q; DN*  
(
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public static void log(int sMsg) RK%N:!fq=  
{ CSF-2lS
G  
System.err.println(sMsg); FJ]BB4 K  
} J+oK:tzt8  
} M(>"e*Pi  
}T([gc7~  
Fljqh8c5  
/* VNKtJmt  
**TestMethod.java m,UMb#7Y  
*/ .|=~x3mPw  
package NetFox; !ER,o_T<  
nlv8HC  
Ubtu?wRBW  
public class TestMethod { n^Co  
Th&-n%r9K  
8%-+@\=  
public TestMethod() KI&+Zw4VL  
{ ///xx/weblogic60b2_win.exe SymBb}5  
try{ bF'Y.+"dr  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Jv*[@ -.k  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rGjP|v@3^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iDp'M`(6h  
fileFetch.start(); ,S.<qmf  
} r)S tp`p  
catch(Exception e){e.printStackTrace ();} #
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b[}f]pB@n  
} 1+`Bli]dE  
fZM)>  
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public static void main(String[] args) W$_}lE$  
{ <Z^P8nu  
new TestMethod(); [,;h1m ~iX  
} fB.xjp?  
} ~zdHJ8tYp  
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