http断点续传简单实现（java)

/* S3Xl  
**SiteFileFetch.java ope^~+c~\  
*/ ar+9\  
package NetFox; x7<K<k;s  
import java.io.*; @Z:l62l=bE  
import java.net.*; 60?%<oJ oH  
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+Q"4Migbe@  
public class SiteFileFetch extends Thread { *#+An<iT ;  
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|#R7wnE[k~  
SiteInfoBean siteInfoBean = null; //文件信息Bean $Ri; ^pZw[  
long[] nStartPos; //开始位置 59;KQ  
long[] nEndPos; //结束位置 wgGl[_)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^WWQI+pk  
long nFileLength; //文件长度 &7tbI5na@  
boolean bFirst = true; //是否第一次取文件 vy:Z/1q  
boolean bStop = false; //停止标志 &E5g3lf  
File tmpFile; //文件下载的临时信息 >7DhTM-A  
DataOutputStream output; //输出到文件的输出流 }9}h*RWm  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @?]RBX?a  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5#E`=C%  
{ &`2)V;t  
siteInfoBean = bean; 8$Y9ORs4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $X
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hf&9uHN%7m  
if(tmpFile.exists ()) f x+/C8GK  
{ 88wa7i*  
bFirst = false; ri-b=|h2j  
read_nPos(); J)p l|I  
} q9s=~d7  
else r$s Qf&=  
{ ;vjOUn[E  
nStartPos = new long[bean.getNSplitter()]; V1B5w_^>h'  
nEndPos = new long[bean.getNSplitter()]; p9{mS7R9T  
} >(t6.=  
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} j*r{2f4Rt  
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public void run() i?^L/
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{ =U?dbSf1*  
//获得文件长度 j/?kL{B  
//分割文件 X$W~mQma6  
//实例FileSplitterFetch <frutU16\  
//启动FileSplitterFetch线程 u;2[AQ.  
//等待子线程返回 ge8ZsaiU  
try{ WdbedU~`Q  
if(bFirst) .3Oap*X  
{ a<bwzX|.  
nFileLength = getFileSize(); T1=fNF  
if(nFileLength == -1) d>qY{Fdz  
{ 'm kLCS  
System.err.println("File Length is not known!"); &&>ekG9@  
} /h|#J  
else if(nFileLength == -2) Wg]Qlw`\|  
{ 9CD_os\h  
System.err.println("File is not access!"); H$UcF1k<  
} ~2-1 j  
else r3UUlR/Do  
{ 1
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for(int i=0;i<nStartPos.length;i++) ^^D0^k!R  
{ >tW#/\x{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sLxc(d'A  
} o|["SYIf  
for(int i=0;i<nEndPos.length-1;i++) A^<jy=F&  
{ |aq"#Ml)  
nEndPos = nStartPos[i+1]; J
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} HLG"a3tt  
nEndPos[nEndPos.length-1] = nFileLength; `3&v6  
} rmg}N  
} 7J<5f)  
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//启动子线程 Wvf ^N(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C1QA)E['V  
for(int i=0;i<nStartPos.length;i++) 0flRh)[J  
{ z-)O9PV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1yu4emye4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BnasI;yWb  
nStartPos,nEndPos,i); wz%NbLy-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *gWwALGo5  
fileSplitterFetch.start(); xU`p|(SS-  
} )\$|X}uny&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 97!;.f-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +52{-a,>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -nV9:opD  
nEndPos = " + nFileLength); oNF6<A(@$  
// fileSplitterFetch[nPos.length-1].start(); pFjK}JOF  
*J`O"a  
/9fR'EO{x  
//等待子线程结束 O:Tj"@h  
//int count = 0; Xc&9Glf  
//是否结束while循环 Qzw;i8n{  
boolean breakWhile = false; /m

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EXqE~afm2  
while(!bStop) }0Ed]  
{ l+^*LqEW2  
write_nPos(); |&i<bqLw:  
Utility.sleep(500); {"KMs[M  
breakWhile = true; `<d }V2rdz  
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kE1TP]|  
for(int i=0;i<nStartPos.length;i++) }k.Z~1y  
{ >fQMXfoY  
if(!fileSplitterFetch.bDownOver) *\F~[  
{ m ~$v;?i  
breakWhile = false; X!EP$!  
break; a9V,es"BWQ  
} R0*|Lo$6  
} X#
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if(breakWhile) G]&qx`TBK  
break; }Jj}%XxKs  
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+mT_QsLEv  
//count++; |+D!= :x  
//if(count>4) KoT%Mfu  
// siteStop(); FfT

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} .8JTe0  
88$8d>-  
5\VWCI  
System.err.println("文件下载结束！"); c@L< Z`u  
} U|R_OLWAg  
catch(Exception e){e.printStackTrace ();} H0vfUF53l  
} DkDmE  
l+0oS'`V*L  
BnF^u5kv%  
//获得文件长度 8zW2zkv2|#  
public long getFileSize() =41?^1\  
{ =Nr-iae#  
int nFileLength = -1; g*+>H1}  
try{  N4TV  
URL url = new URL(siteInfoBean.getSSiteURL()); (X*^dO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MkXmA`cP  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8'y$M] e9n  
0?|<I{z2  
*.w9c  
int responseCode=httpConnection.getResponseCode(); Z6MO^_m2  
if(responseCode>=400) !0<,@v"  
{ 44j*KsBf  
processErrorCode(responseCode); SiN0OB  
return -2; //-2 represent access is error ]u/sphPe  
} h^P#{W!e\  
;L ^o*`  
`r 4fm`<  
String sHeader; XC#oB~K'  
aV0"~5  
]\HvKCN}  
for(int i=1;;i++) /&JT~M  
{ s_p!43\J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  6(R<{{  
//Utility.log(in.readLine()); [AJJSd/:  
sHeader=httpConnection.getHeaderFieldKey(i); nQ3A~ ()  
if(sHeader!=null) &q*Aj17  
{ 42ge3>  
if(sHeader.equals("Content-Length")) ,
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{ w7&A0M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); k$:|-_(w  
break; t4-[Z$n5  
} TIg3`Fon  
} B^}yo65I  
else {R{=+2K!|k  
break; _Y m2/3!  
} v4 E}D  
} 6Q5^>\Y  
catch(IOException e){e.printStackTrace ();} 0jWVp-y  
catch(Exception e){e.printStackTrace ();} Bk{]g=DO  
vtJJ#8a]  
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Utility.log(nFileLength); lPAQ3t!,  
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return nFileLength; buHJB*?9  
} 7F~X,Dk_  
9} .z;prz  
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//保存下载信息（文件指针位置） sV*H`N')S  
private void write_nPos() XQw9~$  
{ )0k53-h&  
try{ *lJxH8\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); [dVL&k<P  
output.writeInt(nStartPos.length); bpa?C  
for(int i=0;i<nStartPos.length;i++) 3=V&K-  
{ 'dc#F3  
// output.writeLong(nPos); ZSo)  
output.writeLong(fileSplitterFetch.nStartPos);  e]$s t?  
output.writeLong(fileSplitterFetch.nEndPos); F_P~x(X  
} 3o/[t  
output.close(); :[d9tm  
} b|(:[nB  
catch(IOException e){e.printStackTrace ();} |JsZJ9W+J  
catch(Exception e){e.printStackTrace ();} Y}KNKO;  
} a?oI>8*  
&uVnZ@o42  
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//读取保存的下载信息（文件指针位置） 5#z1b
u
 
private void read_nPos() ZYNsHcTY  
{ M D#jj3y  
try{ AQ^u  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); + >!;i6|  
int nCount = input.readInt(); #4;wjcGWw  
nStartPos = new long[nCount]; qZZK#,Qb  
nEndPos = new long[nCount]; )QJUUn#  
for(int i=0;i<nStartPos.length;i++) (**oRwr%  
{ ]eV8b*d6  
nStartPos = input.readLong(); m(P]k'ZH?  
nEndPos = input.readLong(); -D:b*D  
} 1{.9uw"2S  
input.close(); X5w$4Kj&4l  
} A]3k4DLYS  
catch(IOException e){e.printStackTrace ();} \GU<43J2uo  
catch(Exception e){e.printStackTrace ();} b\5F]r  
} !bP@n  
{K!)Ss  
o{[qZc_%  
private void processErrorCode(int nErrorCode) bW:!5"_{H  
{ )LCHy^'  
System.err.println("Error Code : " + nErrorCode); MWh6]gGs  
} W}ofAkF  
-tU'yKhn  
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//停止文件下载 =i3n42M#  
public void siteStop() !ubD/KE  
{ lmhLM. 2  
bStop = true; 2 ? 4!K.  
for(int i=0;i<nStartPos.length;i++) \}G^\p6?M  
fileSplitterFetch.splitterStop(); .A|@?p[  
u]G\H!WkQ  
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} A?0Nm{O;3v  
} O33`+UV"W  
//负责部分文件的抓取 ^kSqsT"  
**FileSplitterFetch.java %]7d`/  
*/ 2t1ZIyv3D  
package NetFox; Kf
-JcBsrT  
onV>.7sG  
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import java.io.*; Y|/ 8up  
import java.net.*; VS|2|n1<6  
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public class FileSplitterFetch extends Thread { VG~Vs@c(  
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String sURL; //File URL N)Z?Z+}h  
long nStartPos; //File Snippet Start Position EBmt9S
 
long nEndPos; //File Snippet End Position #|``ca54B  
int nThreadID; //Thread's ID /wlEe>i  
boolean bDownOver = false; //Downing is over Ht&YC<X  
boolean bStop = false; //Stop identical -%4,@ x`  
FileAccessI fileAccessI = null; //File Access interface @[v~y"tE}  
-DAlRz#d,  
9Gz=lc[!7  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >5SSQ\2~a  
{ lUMdrt0@z  
this.sURL = sURL; XB5DPx  
this.nStartPos = nStart; \.}c9*)  
this.nEndPos = nEnd; 9MqGIOQ${j  
nThreadID = id; hFBe,'3M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]
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} ,v}k{( 16{  
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-|9=P\U8S  
public void run() \lNN Msd&  
{ v(%*b,^  
while(nStartPos < nEndPos && !bStop) -H-~;EzU  
{ rU(+T0t?I  
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try{ BfiD9ka-z  
URL url = new URL(sURL); ~7Ux@Sx;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yEQs:v6L~  
httpConnection.setRequestProperty("User-Agent","NetFox"); /2VJX@h  
String sProperty = "bytes="+nStartPos+"-"; 9-m=*|p  
httpConnection.setRequestProperty("RANGE",sProperty); Qe(
:|q_  
Utility.log(sProperty); ku M$UYTTX  
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InputStream input = httpConnection.getInputStream(); dUdT7ixo  
//logResponseHead(httpConnection); 5Jnlz@P9  
E&:,oG2M  
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byte[] b = new byte[1024]; oe~b}:  
int nRead; f(7GX3?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P0jtp7)7  
{ Fv`,3aNB  
nStartPos += fileAccessI.write(b,0,nRead); 6;5Ss?ep  
//if(nThreadID == 1) iDrZc  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q=yg8CQ  
} ;YL i{  
Z;)%%V%o  
%vi83%$'4  
Utility.log("Thread " + nThreadID + " is over!"); BING
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bDownOver = true; vs{s_T7Mz]  
//nPos = fileAccessI.write (b,0,nRead); R0-j5&^jju  
} lU8Hd|@-  
catch(Exception e){e.printStackTrace ();} K!l5coM  
} a7%]Y}$  
} |]*/R^1>2  
;i+#fQO7Q  
8DaL,bi*.  
//打印回应的头信息 ^sWT:BDh  
public void logResponseHead(HttpURLConnection con) o2\8OxcA  
{ 8, >P  
for(int i=1;;i++) d m%8K6|  
{ ;i:d+!3XwC  
String header=con.getHeaderFieldKey(i); hP&Bt  
if(header!=null) U~7c+}:c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ufT`"i  
Utility.log(header+" : "+con.getHeaderField(header));
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else '1/i"yoW  
break; |$_sX9\`?|  
} @U
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} H} g{Cr"Ex  
|LKXOU c  
DM>eVS3}  
public void splitterStop() VVOd]2{  
{ 3sZ\0P}   
bStop = true; ,s;UfF  
} 5l*&>C[(i  
=_u4=4
 
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} VY\&8n}e(  
9'q*:&qq  
)53y AyP  
/* *CHX  
**FileAccess.java *4Y Vv  
*//文件访问(定位，写) (Ep\Z 6*  
package NetFox; [!OxZ!  
import java.io.*; |ZBI *  
#Mw8^FST  
8}UIbF  
public class FileAccessI implements Serializable{ b|W=pSTY  
$E.I84UfX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 N87B8rDl  
RandomAccessFile oSavedFile; ?FcAXA/J{  
long nPos; cExS7~*  
*;*r8[U}q  
PwLZkr@4^  
public FileAccessI() throws IOException -3Vx76Y  
{ |
$b}L7_  
this("",0); 5XBH$&Td  
} Ph>%7M%  
"9e\c;a  
o"#\ >  
public FileAccessI(String sName,long nPos) throws IOException
IO-Ow!  
{ [ibu/W$  
oSavedFile = new RandomAccessFile(sName,"rw"); vRO _Q?  
this.nPos = nPos; ?5 7Sk+  
oSavedFile.seek(nPos); g}',(tPMZ  
} ~Jz6O U*z  
[hj6N*4y  
S^\Vgi(  
public synchronized int write(byte[] b,int nStart,int nLen) /t"3!Z?BOv  
{ oILZgNe'  
int n = -1; +; AZ+w]ZF  
try{ Y0-n\|  
oSavedFile.write(b,nStart,nLen); @I!0-OjL  
n = nLen; LSr]S79N1  
} ~R92cH>L  
catch(IOException e) ,\%c^,HLJ  
{ )I.$=s  
e.printStackTrace (); B0]~el  
} 6,{$J  
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return n; QMbOuw  
} (JFWna0@  
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} YcpoL@ab  
;;N9>M?b  
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/* I9hK}
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**SiteInfoBean.java kpN)zxfk  
*/ %OOl'o"V{s  
package NetFox; `RL"AH:+  
j#q-^
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public class SiteInfoBean { pg)WKbV  
*CI#+P  
5]Y?m'  
private String sSiteURL; //Site's URL }S<2A7)el  
private String sFilePath; //Saved File's Path '16b2n+F@#  
private String sFileName; //Saved File's Name V[Ui/M!9Z  
private int nSplitter; //Count of Splited Downloading File ,1o FPa{?  
j+ 0I-p  
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public SiteInfoBean() ^,T(mKS  
{//nSplitter的缺省值为5 }?Ai87-{  
//default value of nSplitter is 5 -C?ZB}`   
this("","","",5); L0WN\|D  
} b!5~7Ub.No  
UrEs4R1#  
:E )>\&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O[JL+g4  
{ 6G""I]uT  
sSiteURL= sURL; o]I\6,T/|  
sFilePath = sPath; %/#NK1&M  
sFileName = sName; {[?(9u7R  
this.nSplitter = nSpiltter; 1NA.nw.  
^sLdAC  
Cd}<a?m,  
} 68WO~*  
\n|EM@=eE  
nk's_a*Z  
public String getSSiteURL() sN01rtB(UT  
{ 6zuTQ^pz  
return sSiteURL; fHd#u%63K  
} $C$V%5aA  
V{3x!+q  
-fW*vE:  
public void setSSiteURL(String value) &(l9?EVq1  
{ #fn)k1  
sSiteURL = value; ,M ^<CJ  
} @O^6&\s>  
dE{dZ#Jfi  
]Ntmy;Q  
public String getSFilePath() jkF
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{ =R$u[~Xl2X  
return sFilePath; @>Km_Ax  
} VY=jc~c]v  
h^(*Tv-!  
+E(L\  
public void setSFilePath(String value) = x)-u8P  
{ DAr1C+Dy  
sFilePath = value; '$]97b7G  
} >$/>#e~  
mLLDE;7|}  
]:k/Y$O2  
public String getSFileName() C7ScS"~  
{ 84zSK)=Y  
return sFileName; uo%)1NS!  
} rlSeu5X6  
~ =2PU$u  
x@;m8z0  
public void setSFileName(String value) 4yr'W8X_  
{ a![{M<Y~  
sFileName = value; h_,i&d@(  
} j@3Q;F0ba  
q\4Xs$APq  
9W1YW9rL  
public int getNSplitter() ~H<6gN<j(.  
{ +.b,AqJ/  
return nSplitter; .2Elr(&*h  
} H;k~oIsk  
3<f}nfB%r?  
2E)-M9ds  
public void setNSplitter(int nCount) 9ZsVy
 
{ k|PN0&J  
nSplitter = nCount; M; tqp8  
} :vQrOn18p  
} :zke %Yx  
5 ,B_u%bb  
0{p#j~ZhC  
/* `*N[jm"  
**Utility.java A>
;bHf@  
*/ :g=qz~2Xk  
package NetFox; umH40rX+  
MK
D
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;)z:fToh  
public class Utility { Y0dEH^I  
x,@B(9No  
Q%f^)HZGR  
public Utility() nuMD!qu!nZ  
{ g63(E,;;J  
/cQueUME`  
vDhh>x(  
} B:S>wFE(.  
i
0kak`x0  
//线程睡眠 }t=!(GOb}  
public static void sleep(int nSecond) }9#r0Vja  
{ pis`$_kmwV  
try{ 1N#| }ad  
Thread.sleep(nSecond); }Gm>`cw-  
} S8wLmd>  
catch(Exception e) N&+x+;Kx  
{ $)ijN^hV  
e.printStackTrace (); :tB1D@Cb6  
} c&
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} /}fHt^2H  
gpvYb7Of0  
//日志 kY|utoAP  
public static void log(String sMsg) H.|#c^I  
{ GxI!{oi2  
System.err.println(sMsg); FF(#]vz'  
} `O!X((  

/
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public static void log(int sMsg)
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{ SpLzm A  
System.err.println(sMsg); rv^@,8vq  
} n&;85IF1  
} TA`1U;c{n  
=_ ./~  
bz2ztH9 n  
/* i$:*Pb3mV  
**TestMethod.java ;
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*/ L:pYn_  
package NetFox; d *|Y o  
L~rBAIdD  
vrhT<+q  
public class TestMethod { +_?hK{Ib"  
8:c-k|CX  
t?x<g<PJ4  
public TestMethod() rq/yD,I,  
{ ///xx/weblogic60b2_win.exe r6MMCJ|G  
try{ ;4^Rx  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
kHghPn?8]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2G67NC?+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RXpw!  
fileFetch.start(); rb2S7k0{  
} Jr ,;>   
catch(Exception e){e.printStackTrace ();} 'EEJU/"u  
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} qo90t{|c  
'KS,'%  
nQX:T;WL@  
public static void main(String[] args) uD$u2  
{ hk(ZM#Bh  
new TestMethod(); <EB+1GFuI  
} [#<-ZC#T*  
} @fZ,.2ar  
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