http断点续传简单实现（java)

/* w{k^O7
~  
**SiteFileFetch.java Tbv w?3  
*/ TecMQ0 KD  
package NetFox; j%w^8}U>G  
import java.io.*; -\;0gnf{J  
import java.net.*; \)o.Y zAo@  
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-@`Ah|m@}  
public class SiteFileFetch extends Thread { )1Y?S;  
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w$-q&  
SiteInfoBean siteInfoBean = null; //文件信息Bean G}+@C]  
long[] nStartPos; //开始位置 t1J3'lS  
long[] nEndPos; //结束位置 Z2
})n -  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [+R_3'aK  
long nFileLength; //文件长度 X;UEq]kcmn  
boolean bFirst = true; //是否第一次取文件 8zlvzp  
boolean bStop = false; //停止标志 G7v<Q,s  
File tmpFile; //文件下载的临时信息 iDl#foXa`  
DataOutputStream output; //输出到文件的输出流 Yk?q\1  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .s,04xW\  
public SiteFileFetch(SiteInfoBean bean) throws IOException gt(p%~  
{ Do\j_  
siteInfoBean = bean; QKq4kAaJ!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |%ZJN{!R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); wuYak"KX  
if(tmpFile.exists ()) &QW&K  
{ Q3&DA1b`  
bFirst = false; #Y
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read_nPos(); z~~pH9=c2  
} E0fMFG^P  
else esBv,b?*  
{ !u8IZpf  
nStartPos = new long[bean.getNSplitter()]; Eri007?D  
nEndPos = new long[bean.getNSplitter()]; $%"hhju  
} N"G\
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} ^0}wmxDq  
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public void run() n;kWAYgg  
{ (?^F }]  
//获得文件长度 ^p9V5o  
//分割文件 F!u)8>s+z{  
//实例FileSplitterFetch IO 0n
T  
//启动FileSplitterFetch线程 1y1:<t  
//等待子线程返回 myN2G?>;  
try{ "T^%HPif  
if(bFirst) 9{j`eAUZl  
{ lZ[J1:%  
nFileLength = getFileSize(); >4kQ9lXL  
if(nFileLength == -1) eZ[Qhrc  
{ c_+fA  
System.err.println("File Length is not known!"); 6fI2y4yEz  
} $|J+  
else if(nFileLength == -2) 7 L,`7k|  
{ 6Y,&q|K  
System.err.println("File is not access!"); MaY_*[  
} %$Py@g  
else B;NK\5>  
{ }s@IQay+  
for(int i=0;i<nStartPos.length;i++) z;?jKE p  
{ =>3,]hnep  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); O-W[^r2e  
} Q%?%zuU  
for(int i=0;i<nEndPos.length-1;i++) "9aFA(H6w  
{ er-0i L@  
nEndPos = nStartPos[i+1]; Vjt7X"_/  
} cl]W]^q-Cx  
nEndPos[nEndPos.length-1] = nFileLength; *WJK&  
} %5KK#w "  
} v@yqTZ  
fS|e{!iI"  
=A'JIssk  
//启动子线程 ^%Cd@!dk  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; uuF~+=.|  
for(int i=0;i<nStartPos.length;i++) W% Lrp{  
{ =EA @  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XP}5i!}}7=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2YWO'PL  
nStartPos,nEndPos,i); qM26:kB{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q5EkAh<PD|  
fileSplitterFetch.start(); SnXM`v,  
} I{U|'a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ts@$*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8,RqhT)2#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H*3u]Ebh  
nEndPos = " + nFileLength); Q#ksf h!D  
// fileSplitterFetch[nPos.length-1].start(); PHIc7*_  
*?uUP  
N:  38N  
//等待子线程结束 o~9*J)X5i  
//int count = 0; 2 V\hG?<  
//是否结束while循环 >!" Sr3,L  
boolean breakWhile = false; Nv;'Ys P  
:R:@V#Y  
tK{#kApHGG  
while(!bStop) 8,vP']4r%  
{ fSVM[  
write_nPos(); hslT49m>  
Utility.sleep(500); noa+h<vGb  
breakWhile = true; r1RM7y  
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Z"w}`&TC$^  
for(int i=0;i<nStartPos.length;i++) ,98 F  
{ o_Y?s+~i[/  
if(!fileSplitterFetch.bDownOver) US9aW)8  
{ t!J>853  
breakWhile = false; g +gcH  
break; xele;)Y  
} aCQ[Uc<B:  
} b3%a4Gg&  
if(breakWhile) Lwf[*n d  
break; '" &*7)+g*  
"oZ_1qi<  
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//count++; /=9dX; #  
//if(count>4) KV&6v`K/N  
// siteStop(); F 8sOc&L  
} $J)`Ru6.  
r]D>p&4  
}u0&>k|y  
System.err.println("文件下载结束！"); fiSX( 9  
} &{a#8sbf#c  
catch(Exception e){e.printStackTrace ();} gjnEN1T22  
} 'IIa,']H  
D5bi)@G7z  
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//获得文件长度 &K[~Ab_  
public long getFileSize() o::9M_;  
{ 4%_c9nat  
int nFileLength = -1; MzKl=G  
try{ 4A(h'(^7A  
URL url = new URL(siteInfoBean.getSSiteURL()); |G6'GTwZD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5-({z%:P  
httpConnection.setRequestProperty("User-Agent","NetFox"); a+k3wzJ  
saQ ~v@  
#X$s5H  
int responseCode=httpConnection.getResponseCode(); hmuhq:<f  
if(responseCode>=400)
^ .A  
{ "ixea- 2  
processErrorCode(responseCode); jHatUez4O  
return -2; //-2 represent access is error b{-|q6  
} \21Gg%W5AE  
]
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:-hVbS0I  
String sHeader; S-Vxlku]  
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for(int i=1;;i++) !m'R
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{ XA.1Y)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); t&5Ne ?  
//Utility.log(in.readLine()); ?-`&YfF  
sHeader=httpConnection.getHeaderFieldKey(i); OQ<;w  
if(sHeader!=null) ze5#6Vzd&  
{ wCv9VvF`  
if(sHeader.equals("Content-Length")) u:W/6QS  
{ $*_79F2zN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ks(l :oUB  
break; gy|o#&e]%  
} 7u:kR;wk  
} *u,&?fCl  
else {]m/15/$C  
break; BAi0w{  
} 6iEg]FI  
} @/$i -?E  
catch(IOException e){e.printStackTrace ();} !>Q\Y`a,*  
catch(Exception e){e.printStackTrace ();} ^vxNS[C`;  
q?]KZ_a  
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Utility.log(nFileLength); 017nhI  
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return nFileLength; 368 g>/#'  
}
rqm":N8@  
-w)v38iX!  
SXJjagAoML  
//保存下载信息（文件指针位置） uocFOlU0n  
private void write_nPos() )g3c-W=  
{ fN<Y3^i"  
try{ N0\<B-8+,>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); b^}U^2S%  
output.writeInt(nStartPos.length); /"~UGn]R  
for(int i=0;i<nStartPos.length;i++) Q:y'G9b  
{ =9p3^:S  
// output.writeLong(nPos); 4_'BoU4  
output.writeLong(fileSplitterFetch.nStartPos); Wy/h"R\=  
output.writeLong(fileSplitterFetch.nEndPos); v|]"uPxH?  
} n8T'}d+mm  
output.close(); Q6 m.yds  
} lU$0e09  
catch(IOException e){e.printStackTrace ();} ]\}MSo3  
catch(Exception e){e.printStackTrace ();} A =&`TfXu  
} (q}LirR  
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H}CmSo8&  
//读取保存的下载信息（文件指针位置） q68m*1?y  
private void read_nPos() 7<B-2g  
{
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try{ AqaMi  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~>~qA0m"m  
int nCount = input.readInt(); f3>DmH#  
nStartPos = new long[nCount]; U.$Th_  
nEndPos = new long[nCount]; Y5"HK
W^  
for(int i=0;i<nStartPos.length;i++) S>j.i  
{ R)isWw4  
nStartPos = input.readLong(); 6P,uy;PJ  
nEndPos = input.readLong(); N:+d=G`x  
} V 7ZGT  
input.close(); JZ:yPvJ  
} GWWaH+F[h  
catch(IOException e){e.printStackTrace ();} H(M{hfa|  
catch(Exception e){e.printStackTrace ();} m"'`$/_  
}
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qss)5a/x.  
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private void processErrorCode(int nErrorCode) x_C0=Q|K3  
{ d:#tN4y7(  
System.err.println("Error Code : " + nErrorCode); %@TC- xx  
}  tL<.B  
w $`w
 
^7=7V0>,:  
//停止文件下载 E2>+V{TF  
public void siteStop() \.Op6ECV9  
{ "{t]~urLd  
bStop = true; x5/&,&m`%  
for(int i=0;i<nStartPos.length;i++) /s=veiH  
fileSplitterFetch.splitterStop(); ~ ^   
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} }owl7G3  
} *BF[thB:a  
//负责部分文件的抓取 'lu3BQvfh  
**FileSplitterFetch.java )Z['=+s%  
*/ _G25$%/LU  
package NetFox; E7aG&K  
r=54@`O!  
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import java.io.*; %&V%=-O_7  
import java.net.*; S)
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h@(+(fVHrp  
public class FileSplitterFetch extends Thread { n}(A4^=4KQ  
)E^4U9v),  
1Ax;|.KQH  
String sURL; //File URL *0Fz." v  
long nStartPos; //File Snippet Start Position _u~0t`f~  
long nEndPos; //File Snippet End Position %k )H7nj  
int nThreadID; //Thread's ID be5N{lPT@;  
boolean bDownOver = false; //Downing is over lNWP9?X  
boolean bStop = false; //Stop identical b>k2@  
FileAccessI fileAccessI = null; //File Access interface "VU/Ucb7  
|(PS bu  
y=EVpd  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pv-c>8Wb6  
{ DL!%Np?`  
this.sURL = sURL; uhp.Yv@c  
this.nStartPos = nStart; zEukEA^9`  
this.nEndPos = nEnd; N>]J$[j  
nThreadID = id; #k`gm)|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #Q*V9kvU/H  
} #h4FLF_w  
BNI)y@E^X  
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public void run() TOS'|xQ  
{ f#w u~*c  
while(nStartPos < nEndPos && !bStop) Z,Us<du  
{ WjM7s]ZRv  
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W-/V5=?   
try{ u*,>
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URL url = new URL(sURL); c/v|e&q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o; U!{G(X  
httpConnection.setRequestProperty("User-Agent","NetFox"); *kYGXT,f]  
String sProperty = "bytes="+nStartPos+"-"; P+OS  
httpConnection.setRequestProperty("RANGE",sProperty); PiCGZybCA  
Utility.log(sProperty); L/] (pXEp  
yBIX<P)vE'  
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InputStream input = httpConnection.getInputStream(); )c'E9ZuZ>d  
//logResponseHead(httpConnection); aW{5m@p{"  
x-%RRm<V  
ftl?x'P%  
byte[] b = new byte[1024]; 9n;6zVV%`  
int nRead; `ZI-1&Y3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (K84J*;  
{ R*6B@<p,i  
nStartPos += fileAccessI.write(b,0,nRead); .5}Gt>4XM  
//if(nThreadID == 1) 57gt"f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .Y^cs+-o  
} N2duhI6  
V %D1Q}X  
32%Fdz1S  
Utility.log("Thread " + nThreadID + " is over!"); ,c{ckm  
bDownOver = true; ?h%Jb^#9  
//nPos = fileAccessI.write (b,0,nRead); 150-'Q  
} NVsaV;u  
catch(Exception e){e.printStackTrace ();} ~T-uk  
} ar}-~~h 5  
} 7Zdg314  
9:-7.^`P  
}f?[m&<  
//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) A~<!@`NjB  
{ [(5.?  
for(int i=1;;i++) `&OX|mL^w  
{ b:p0@|y  
String header=con.getHeaderFieldKey(i); -GHd]7n  
if(header!=null) DZnqCu"J  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _ezRE"F5  
Utility.log(header+" : "+con.getHeaderField(header)); Y|Gp\  
else qq)}GK8K&  
break; xdM'v{N#m  
} #u8#< ,w  
} 9q_{_%G%  
[3nWxFz$R  
dr:x0>  
public void splitterStop() g3>>gu#0DC  
{ hd~#I<8;2  
bStop = true; vO~Tx  
} 1PUZB`"3  
,p#B5Dif/  
,I x>.^|  
} dM= &?g  
s-PS]l@  
{5<fvMO!6  
/* 9 i/ (  
**FileAccess.java )E>yoUhN  
*//文件访问(定位，写) Y<irNp9  
package NetFox; f pq|mY  
import java.io.*; 6uFw+Ya#  
-bHlFNRm  
1Kk6nUIN  
public class FileAccessI implements Serializable{ Abt<23$h  
%'2.9dB  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 NLG\*mQ  
RandomAccessFile oSavedFile; Q!V:=d  
long nPos; -$[&{.B.  
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R#^ku)0  
public FileAccessI() throws IOException ^4^N}7>5  
{ BOG.[?yx  
this("",0); _avf
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} |.0~'  
_OuNX.yrG  
K3[+L`pz  
public FileAccessI(String sName,long nPos) throws IOException ~h;   
{ 4dPTrBQ?  
oSavedFile = new RandomAccessFile(sName,"rw"); @=dv[P"jn  
this.nPos = nPos; x0(bM g>7  
oSavedFile.seek(nPos); 2(@2z[eKr  
} xwof[BnEZ  
6{1=3.CL  
{>msE }L  
public synchronized int write(byte[] b,int nStart,int nLen) rD SYR\cg  
{ 9|Jv>Ur=)2  
int n = -1; &TQ~!ZMOR"  
try{ \+O.vRc"M  
oSavedFile.write(b,nStart,nLen); Z6i~Dy3  
n = nLen; PD.$a-t  
} S,AxrQc  
catch(IOException e) [B)!  
{ 5 k3m"*  
e.printStackTrace (); /u4RZ|&as  
} C`g "Mk8  
3rH}/`d4  
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return n; j2_j5Hgo  
} xS/W}-dPv  
%N<5ST>(  
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} bkDVW  
:QGo -,6-  
K%\r[NF  
/* yT@Aj;X0v  
**SiteInfoBean.java h' !C  
*/ ?0qD(cfx<  
package NetFox; ^WO3,  
{jB>]7  
e,e(t7c?d  
public class SiteInfoBean { 'QT~o-U  
kWZY+jyt P  
W{"sB:E  
private String sSiteURL; //Site's URL ?I[8rzBWU  
private String sFilePath; //Saved File's Path BA2"GJvfIA  
private String sFileName; //Saved File's Name O?Bf (y  
private int nSplitter; //Count of Splited Downloading File v7 *L3Ol  
xyk%\&"7  
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public SiteInfoBean() Mu[lk=jC  
{//nSplitter的缺省值为5 #:gl+  
//default value of nSplitter is 5 [8sYEh  
this("","","",5); OVi<d  
} Ul_Zn  
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|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) d/Q#Z  
{ t2(X  
sSiteURL= sURL; .))jR:{3  
sFilePath = sPath; 3&^hf^yg  
sFileName = sName; 7 mCf*|  
this.nSplitter = nSpiltter;
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Q  
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} 1Z< ^8L<  
8>eYM  
rzAf {2  
public String getSSiteURL() O>]i?  
{ F(ydq
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return sSiteURL; y2_rm  
} ;^xM" {G8  
u>fMO9X}2  
6U*CR=4  
public void setSSiteURL(String value) \s*UUODWK  
{ I2$DlEke  
sSiteURL = value; gD6S%O  
} p6<JpW5@_  
@@oJ@;  
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public String getSFilePath() (uvQ/!  
{ MT~^wI0a  
return sFilePath; T$D(Y`zdn  
} 5,gT|4|B\g  
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~6t!)QATnp  
public void setSFilePath(String value) $vu*# .w  
{ -n9&W  
sFilePath = value; ^\ x'4!W  
} fY&TI}Y  
#!F>cez  
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public String getSFileName() S<i1t[E@W  
{ w&L~+Z<  
return sFileName; O.B9w+G=  
} EN2t}rua  
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p$\>3\  
public void setSFileName(String value) v ^h:E  
{ ~ZVz sNrx  
sFileName = value; (BLxK)0<"  
} vd ls
s|  
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X=whZ\EZ  
public int getNSplitter() AE77i,Xa  
{ N4ZV+ |  
return nSplitter; ({j8|{)+  
} rgVRF44X{  
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H\QkU`b  
public void setNSplitter(int nCount) W\zZ&*8$  
{ J~5V7B  
nSplitter = nCount; S9l,P-X`  
} r"2lcNE  
} X=#us7W}  
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[o<hQ`&  
/* v>wN O  
**Utility.java q|<B9Jk  
*/ !vf:mMo  
package NetFox; 8+[Vo_]  
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vQ*[tp#qU  
public class Utility { 0fewMS*  
FJZ'P;3  
i1uoYb?4(I  
public Utility() ni2#20L  
{ ~".@mubt1$  
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} -E?:W`!  
%FYhq:j  
//线程睡眠 5\pS8<RJ;  
public static void sleep(int nSecond) Xeq9Vs zg  
{ sg7h&<Xx  
try{ CnB[ImMs(A  
Thread.sleep(nSecond); j<~Wp$\i7>  
} 3FR(gr$X  
catch(Exception e) SQ,-45@W  
{ '*y(F*7+  
e.printStackTrace (); j_2g*lQ7a  
} TMMKRC1<  
} _+By=B.'  
P#hRqETw  
//日志 \eKXsO"d  
public static void log(String sMsg) 1.+O2qB  
{ }%Mdf6LS64  
System.err.println(sMsg); M v(Pp  
}  nz?[  
xJ$uoy3+  
zTcz+3x  
public static void log(int sMsg) %8n<#0v-|4  
{ u*@R`,Y   
System.err.println(sMsg); ! :]_-DX  
} ht2Fie  
} Cw(e7K7&  
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z)C}}NH*!@  
/* #4m5I="  
**TestMethod.java VF2,(f-*  
*/ 6#U~>r/  
package NetFox; ]!AS%D`  
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public class TestMethod { I4N7wnBp  
zU!{_Ao9  
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public TestMethod() [`GSc6j  
{ ///xx/weblogic60b2_win.exe r[V%DU$dj  
try{ F)cCaE;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J-<P~9m~I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); XDCm
 
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7N 0Bj!  
fileFetch.start(); Hes!uy  
} o>M^&)Xs  
catch(Exception e){e.printStackTrace ();} hhPQ.{]>  
e^eJ!~0  
t}R!i-D|HB  
} 8j>V?'Szk  
r7W.}n*  
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public static void main(String[] args) ~}b0zL  
{ n3$=&  
new TestMethod(); Q$U.vF7BnP  
} &$|~",  
} >;Hx<FKxP  
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