http断点续传简单实现（java)

/* lT'9u,6  
**SiteFileFetch.java PY`L$e  
*/  %v+=;jw  
package NetFox; P`S@n/}  
import java.io.*; $d/&k`  
import java.net.*; ecj7BT[mLI  
; Y"N6%
 
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public class SiteFileFetch extends Thread { 7AwgJb hn  
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{{C  
SiteInfoBean siteInfoBean = null; //文件信息Bean ";x+1R.d  
long[] nStartPos; //开始位置 y<- _(^  
long[] nEndPos; //结束位置 QJn`WSw$_-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c>HK9z{  
long nFileLength; //文件长度 l>6@:nq|R  
boolean bFirst = true; //是否第一次取文件 =8Ehrlq
 
boolean bStop = false; //停止标志 RO&H5m r%@  
File tmpFile; //文件下载的临时信息 ;apzAF  
DataOutputStream output; //输出到文件的输出流 ^e Gue  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） a.@qGsIH  
public SiteFileFetch(SiteInfoBean bean) throws IOException uuNR?1fS  
{ .fYZ*=P;c  
siteInfoBean = bean; !ABiy6d  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yClx` S(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zR;X*q"T$4  
if(tmpFile.exists ()) -|S]oJy  
{ '?QuJFki  
bFirst = false; 1LnyWZ  
read_nPos(); K_/zuTy  
} &a,OfSz  
else l?8M p$M  
{ FLZWZ;  
nStartPos = new long[bean.getNSplitter()]; "LhvzM-<8  
nEndPos = new long[bean.getNSplitter()]; Oakb'  
} _>m-AI4^  
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} qZv =  
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public void run() FR[ B v  
{ <A5]]{9 +  
//获得文件长度 H*^
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//分割文件 ^Xb7[+I6  
//实例FileSplitterFetch 4Y> Yi*n  
//启动FileSplitterFetch线程 I<td1Y1q  
//等待子线程返回 wXMDh$  
try{ }@1q@xU  
if(bFirst) $2^
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{ "9EE1];NT  
nFileLength = getFileSize(); ltB.Q  
if(nFileLength == -1) `:m!~  
{ m([(:.X/IX  
System.err.println("File Length is not known!"); )tHaB,  
} 7uorQfR?  
else if(nFileLength == -2) "gtHTqheH  
{ K;hh&sTB  
System.err.println("File is not access!"); "xmP6=1  
} C?
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else !Z!g:II /  
{ Migd(uw'  
for(int i=0;i<nStartPos.length;i++) `1*nL,i  
{ p(;U@3G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Pi,QHb`>  
} ?[<Tx-L  
for(int i=0;i<nEndPos.length-1;i++) 0~wF3BgV  
{ h&.wo !  
nEndPos = nStartPos[i+1]; Jj~EiA  
} wbDM5%  
nEndPos[nEndPos.length-1] = nFileLength; R[z`:1lo  
} TD[EQ  
} ]5~s"fnG  
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//启动子线程 Gb[`R}^dq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; iovfo2!hD  
for(int i=0;i<nStartPos.length;i++) Zwcy4>8  
{ )"zvwgaW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HEL!GC>#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gBT2)2]  
nStartPos,nEndPos,i); -9RDr\&`(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8[r9HC  
fileSplitterFetch.start(); 0;S,tJg  
} O}9KJU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PB%-9C0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M(#m0xB  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }
N_
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nEndPos = " + nFileLength); 5@*'2rO&!  
// fileSplitterFetch[nPos.length-1].start(); yC 77c=  
(-]r~Ol^  
G?f\>QSZ  
//等待子线程结束 gaA<}Tp,  
//int count = 0; syU9O&<  
//是否结束while循环 $^u}a  
boolean breakWhile = false; UAR5^  
#r PP*  
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while(!bStop) 988]}{w  
{ 7t,t`  
write_nPos(); zlR?,h-[3  
Utility.sleep(500); r=yK,d/1  
breakWhile = true; u77E! z4Uz  
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for(int i=0;i<nStartPos.length;i++) ==i[w|  
{ V\(:@0"  
if(!fileSplitterFetch.bDownOver) .>z][2oz  
{ $}")1|U,X  
breakWhile = false; R/"x}B1d  
break; x `V;Y]7'  
} }|%eCVB  
} 52upoU>}2  
if(breakWhile) ~=R SKyzt  
break; ]%Zz \Q  
iNwqF0  
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//count++; s1?[7yC  
//if(count>4) r\nx=  
// siteStop(); npRSEv  
} i-yy/y-N  
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=@F&o4)r  
System.err.println("文件下载结束！"); (H+'X}1  
} K'#E3={tt  
catch(Exception e){e.printStackTrace ();} a<]B B$~  
} AyMd:5;  
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//获得文件长度 G\NPV
'  
public long getFileSize() G%d (
 
{ ?WE  
int nFileLength = -1; &~CY]PN.  
try{ a~8[<Fomj  
URL url = new URL(siteInfoBean.getSSiteURL()); "vtCTl~t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :x_'i_w  
httpConnection.setRequestProperty("User-Agent","NetFox"); V]90  
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int responseCode=httpConnection.getResponseCode(); s`>[F@N7.o  
if(responseCode>=400) wj[$9UJb  
{ y!]CJigpZ  
processErrorCode(responseCode); i1RiGS
 
return -2; //-2 represent access is error h;3cd0  
} )& u5IA(  
)Wb0u0)_  
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String sHeader; 7=(Hy\Q5xH  
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for(int i=1;;i++) |r bWYl.b  
{ |*`Z*6n  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "O(9m.CZ  
//Utility.log(in.readLine()); "W(Q%1!Wi  
sHeader=httpConnection.getHeaderFieldKey(i); Qyy.IPTP  
if(sHeader!=null) 4 {9B9={  
{ 8
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if(sHeader.equals("Content-Length"))
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{ $v Z$'(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^n+!4(@=  
break; DfKr[cqLM  
} V%Sy"IG  
} tY <Z'xA?  
else ;,]P=Ey  
break; @$T 9Ll  
} H8"@iE,  
} _2N$LLbg  
catch(IOException e){e.printStackTrace ();} <vwkjCA`  
catch(Exception e){e.printStackTrace ();} QD%L0;j  
!fj(tPq  
6"}?.E$  
Utility.log(nFileLength); 7k8pZ  
<qGu7y"  
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return nFileLength; YQY%M>F@d%  
} P@FHnh3}Z$  
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)wNP( @$L  
//保存下载信息（文件指针位置） r\/+Oa'  
private void write_nPos() y '!m4-  
{ ^yOZArc'r  
try{ *BR^U$,e  
output = new DataOutputStream(new FileOutputStream(tmpFile)); f;b[w

 
output.writeInt(nStartPos.length); YIjTL!bA"  
for(int i=0;i<nStartPos.length;i++) &%-73nYw  
{ w4gg@aO  
// output.writeLong(nPos);
!50[z:  
output.writeLong(fileSplitterFetch.nStartPos); pWJFz-  
output.writeLong(fileSplitterFetch.nEndPos); c$yk s  
} TtTj28k7  
output.close(); )`(p
9
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} &n8_0|gK  
catch(IOException e){e.printStackTrace ();} i=oU;7~zK  
catch(Exception e){e.printStackTrace ();} M]2]\km  
} (bH`x]h#  
v: OR   
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//读取保存的下载信息（文件指针位置） N@Uy=?)ZJ  
private void read_nPos() /Y2}a<3&0  
{ 7E79-r&n  
try{ vkEiOFU!u  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }%{LJ}\Px  
int nCount = input.readInt(); cmU1!2.1E  
nStartPos = new long[nCount]; :Ra,Eu  
nEndPos = new long[nCount]; `3WFjU5a  
for(int i=0;i<nStartPos.length;i++) +{f:cea (1  
{ %|q>pin2  
nStartPos = input.readLong(); 9\BT0kx  
nEndPos = input.readLong(); g'n7T|h ~  
} (jRm[7H  
input.close(); `n@*{J8  
} QLiu2U o  
catch(IOException e){e.printStackTrace ();} @] DVD  
catch(Exception e){e.printStackTrace ();} |es?;s'  
} eoG$.M"  
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private void processErrorCode(int nErrorCode) lJ}_G>GJ  
{ 2j}\3Pi  
System.err.println("Error Code : " + nErrorCode); Rnr(g;2  
} jZ~n[ f+Q  
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//停止文件下载 xqG[~)~  
public void siteStop() 8m\7*l^D:  
{ SwTL|+u  
bStop = true; <66X Xh.  
for(int i=0;i<nStartPos.length;i++) (3Two}  
fileSplitterFetch.splitterStop(); :toh0oB[  
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} 8hOk{xs8  
} D%OQ e#!  
//负责部分文件的抓取 7vrl'^1  
**FileSplitterFetch.java ff,pvk8N5  
*/ diL+:H  
package NetFox; l1OE!W W  
:t8b39
  
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import java.io.*; M"p  
import java.net.*; (|:M&Cna]  
Ln')QN  
Tc>  
public class FileSplitterFetch extends Thread { N kb|Fd/s  
5\5/   
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String sURL; //File URL MDhRR*CBh  
long nStartPos; //File Snippet Start Position LrM=*Rh,O  
long nEndPos; //File Snippet End Position WM7oM~&{6  
int nThreadID; //Thread's ID ~?4PBq  
boolean bDownOver = false; //Downing is over n'wU;!W9  
boolean bStop = false; //Stop identical ZRh~`yy  
FileAccessI fileAccessI = null; //File Access interface ); !eow  
[YF>:ydk  
f9t6q*a`%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException QRc{vUR&  
{ LSa,1{  
this.sURL = sURL; ]/[FR5>  
this.nStartPos = nStart; &S{RGXj_  
this.nEndPos = nEnd; h58`XH  
nThreadID = id; q>_/u"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H*RC@O_hv  
}
-BrMp%C  
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public void run() \\PjKAsh  
{ }iXDa?6%  
while(nStartPos < nEndPos && !bStop) W98i[Q9A7  
{ "Gfh,e  
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try{ QwNly4  
URL url = new URL(sURL); E ]A#Uy  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dsb`xw  
httpConnection.setRequestProperty("User-Agent","NetFox"); %+@O#P  
String sProperty = "bytes="+nStartPos+"-"; m'Amli@[  
httpConnection.setRequestProperty("RANGE",sProperty); 5A)2} D]  
Utility.log(sProperty); yh Yb'GK  
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InputStream input = httpConnection.getInputStream(); r@72|:,  
//logResponseHead(httpConnection); L"E7#}  
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byte[] b = new byte[1024]; )JDs\fUE  
int nRead; Od)Uv1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4^p5&5F  
{ :By?O"LQ  
nStartPos += fileAccessI.write(b,0,nRead); kW2sY^Rg  
//if(nThreadID == 1) \s/s7y6b+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v6=RY<l"m  
} G! ]k#.^A,  
6bomh2  
]mo-rhDsM  
Utility.log("Thread " + nThreadID + " is over!"); j>*R]mr6  
bDownOver = true; X}=n:Ql'YY  
//nPos = fileAccessI.write (b,0,nRead); sT !~J4  
} KK1gNC4R  
catch(Exception e){e.printStackTrace ();} jlkmLcpf  
} 3*]eigi)  
} q4R5<LW"  
[
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[="e ziM{  
//打印回应的头信息 gwOa$f%O  
public void logResponseHead(HttpURLConnection con) .\[`B.Q  
{ NE"@Bk cm  
for(int i=1;;i++) x^HGVWw_  
{ O,J>/  
String header=con.getHeaderFieldKey(i); r;/4F/6"  
if(header!=null) "w^!/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pf
%=h |  
Utility.log(header+" : "+con.getHeaderField(header)); $h5xH9x ;  
else 1/RsptN"v  
break; {\
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} VbJiZw(aR  
} w QgoN%  
V 
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public void splitterStop() ~"!]
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{ Wl;.%.]>  
bStop = true; D!Q">6_"z  
} o4`hY/<t  
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*  
} *-+&[P]m  
3;)>Fs;  
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/* c;%_EN%  
**FileAccess.java K\>tA)IPSV  
*//文件访问(定位，写) Ot:CPm@  
package NetFox; VcAue!MN  
import java.io.*; I[=j&rK`  
8;z6=.4xtg  
^:K3vC[h;c  
public class FileAccessI implements Serializable{ FjK3 .>'  
6S\C}U/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +)kb(  
RandomAccessFile oSavedFile; rJPb 3F  
long nPos; 7x#Ckep:I  
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public FileAccessI() throws IOException ?bPRxR  
{ EM]s/LD@%  
this("",0); pM x
 
} t]>Lh>G  
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public FileAccessI(String sName,long nPos) throws IOException M>DaQ`b  
{ 4/mig0"N.  
oSavedFile = new RandomAccessFile(sName,"rw"); qi;f^9M%  
this.nPos = nPos; &@%W29:  
oSavedFile.seek(nPos); >fe-d#!{  
} RD\  
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, 3,gG"  
public synchronized int write(byte[] b,int nStart,int nLen) kspTp>~  
{ +hn+K1  
int n = -1; D<|qaHB=  
try{ _8"O$w  
oSavedFile.write(b,nStart,nLen); tYZ[68  
n = nLen; ElS9?Q+  
} *4_jA](  
catch(IOException e) s
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{ u1t%(_h  
e.printStackTrace (); HOw-]JSP2  
} WtViW=j'  
t>1Z\lE\"  
hZh9uI7.  
return n; 9UKp?SIF  
} uIcn{RZ_z  
uvtF_P/  
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} KC(xb5x Y  
3= 
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8aO~/i:(.  
/* !6s"]WvF  
**SiteInfoBean.java @kk4]:,w  
*/ )jkXSTZ  
package NetFox;  yyv8gH  
,oaw0Vw  
d*A*y^OD  
public class SiteInfoBean { qtiz a~u  
Yu?95qktP  
f@8>HCI  
private String sSiteURL; //Site's URL ~.A)bp  
private String sFilePath; //Saved File's Path 1U^A56CN  
private String sFileName; //Saved File's Name b7
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private int nSplitter; //Count of Splited Downloading File G2t;DN(  
:!5IW?2  
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public SiteInfoBean() vw>2(K=e1  
{//nSplitter的缺省值为5 A3B56K  
//default value of nSplitter is 5 I4i2+ *l}  
this("","","",5); o4*+T8[|5  
} }b=}uiR#  
2P/K K  
f 1w~!O9  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?CC"Yij  
{ kGdt1N[  
sSiteURL= sURL; #{k|I$  
sFilePath = sPath; FDVcow*]n  
sFileName = sName; 3pK*~VK  
this.nSplitter = nSpiltter; ZKQG:M~|  
`}BF${vF  
7<%<Ff@^)O  
} -8r  
=+-Yxh|*  
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public String getSSiteURL() w3=%*<  
{ Z^]|o<.<I  
return sSiteURL; TjQvAkT  
} )RO<o O  
{"&SJ
t[%X  
'XzXZJ[uq  
public void setSSiteURL(String value) iCW*]U  
{ 6KVnnK  
sSiteURL = value; 6B@CurgB  
} ]8T |f  
'@jXbN  
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public String getSFilePath() NzU,va N  
{ RRGWC$>?  
return sFilePath; ?0YCpn  
} 1j:Wh  
={5#fgK>  
$ &P>r  
public void setSFilePath(String value) ~v'3"k6  
{ G
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sFilePath = value; jCrpL~tWT  
} e.@uhB.  
s/7 A7![  
[Z~ 2  
public String getSFileName() ukvtQz)  
{ )ZBY* lk9  
return sFileName; .\8X[%K9nc  
} K-f1{ 0  
:.?gHF.?  
esHQoIhd  
public void setSFileName(String value) {X*^s5{
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{ $uap8nN  
sFileName = value; sf]s",t~J  
} F:D orE  
Rb%%?*|  
5w\fSY  
public int getNSplitter() hUD7_arKF  
{ f{"8g"[[)(  
return nSplitter; 7lS#f1E  
} 0b/WpP  
uA$<\fnz
  
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public void setNSplitter(int nCount) wtT}V=_  
{ m$9w"8R  
nSplitter = nCount; M.nvB)  
} h.!}3\Y  
} DhX#E&  
?%VI{[y#>  
 )@~J  
/* "Tm[t?FMbe  
**Utility.java Fbu5PWhlc  
*/ OiAJ[L  
package NetFox; k{VE1@  
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4GR!y)  
public class Utility { <BO)E(  
`;YU.*  
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public Utility() w=|GJ0  
{ U~W
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V97,1`  
 Y=`
 
} LGc&o]k  
A/7X9ir  
//线程睡眠 H"Klj_<dH0  
public static void sleep(int nSecond) ,v&L:a  
{ lpRR&
  
try{ +525{Tj  
Thread.sleep(nSecond); t+?P^Ok  
} lNv".Y=l  
catch(Exception e) >HPdzLY?  
{ 0 a~HiIh  
e.printStackTrace (); tTN?r8  
} +fx8muz:y  
} ?:|-Dq,  
R.LL#u};  
//日志 U!XS;a)
 
public static void log(String sMsg) @$"L:1_  
{ ;Nr]X  
System.err.println(sMsg); P]i =r] i  
} *_ +7ni  
-o+74=E8[?  
5'w^@Rs5  
public static void log(int sMsg) .)|a2d ~F  
{ ](eN@Xi&@  
System.err.println(sMsg); O)kgBrB  
} !GW,\y  
} OG3/-K8R  
/U6%%%-D`  
CC;! <km  
/* Qp2I[Ioz3  
**TestMethod.java Omi^>c4G  
*/ j#0j)k2Q  
package NetFox; }X;U|]d  
xsjO)))f  
AM} brO  
public class TestMethod { 0)9"M.AIvo  
=2y8CgLj  
s7r9,8$  
public TestMethod() #a| L3zR5v  
{ ///xx/weblogic60b2_win.exe 7n)&FXK`  
try{ w(1Gi$Z(Q)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7&O`p(j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j<pw\k{i  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PN$ .X"D8  
fileFetch.start(); &V7>1kD3  
} O3n_N6| q  
catch(Exception e){e.printStackTrace ();} <B /5J:o<  
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} t ]c{c#N/  
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-{|`H[nmD  
public static void main(String[] args) 5/m$)wE  
{ |m,VTViv;i  
new TestMethod(); '?o9VrO  
} &"uV~AM  
} d~ng6pA  
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