http断点续传简单实现（java)

/* yAU[A  
**SiteFileFetch.java Z{EHV7  
*/ f*Xonb  
package NetFox; i?z3!`m  
import java.io.*; Kw3fpNd  
import java.net.*; ^-w:
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public class SiteFileFetch extends Thread { xAYC%)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean pB|L%#.cW  
long[] nStartPos; //开始位置 }$hxD9z  
long[] nEndPos; //结束位置 J<p<5):R;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 '(5 &Sj/C  
long nFileLength; //文件长度 z) yUBcq  
boolean bFirst = true; //是否第一次取文件 A5!jrSyv  
boolean bStop = false; //停止标志 :J@q Xa  
File tmpFile; //文件下载的临时信息 muQH!Q  
DataOutputStream output; //输出到文件的输出流 `x lsvK>  
2"~!Pu^.j  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <P3r+ 1|R  
public SiteFileFetch(SiteInfoBean bean) throws IOException HLg/=VF7?  
{ 1Z'cL~9  
siteInfoBean = bean; 9hHQWv7TgK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !.zUY6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?O8NyCeb7  
if(tmpFile.exists ()) n <6}  
{ LU_@8i:  
bFirst = false; ilw<Q-o4(  
read_nPos(); ~cz]Rhq  
} =%znY`0b56  
else TgSU}Mf)a  
{ Ox8dnPcx  
nStartPos = new long[bean.getNSplitter()]; B~cq T/\?  
nEndPos = new long[bean.getNSplitter()]; p.n]y=o.)  
} Vl{CD>$,  
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} D
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public void run() |VB}Kv  
{ `)`_G!a  
//获得文件长度 D%LqLLD  
//分割文件 6dV@.(][a  
//实例FileSplitterFetch xrA(#\}f$  
//启动FileSplitterFetch线程  .LEQ r)  
//等待子线程返回 Bz_['7D  
try{ 1.o-2:]E  
if(bFirst) s{NEP/QQJ  
{ >Gk<[0U  
nFileLength = getFileSize(); +Q_X,gZ  
if(nFileLength == -1) qBpv[m  
{ GD}3r:wDs  
System.err.println("File Length is not known!"); i)1E[jc{p!  
} {p|OKf  
else if(nFileLength == -2) kWF4k  
{ Hig=PG5I  
System.err.println("File is not access!"); ;*:d)'A  
} t^&:45~Q  
else Oo`P +S#  
{ (s %T18  
for(int i=0;i<nStartPos.length;i++) i92{N$*x  
{ kI<C\*N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^LfCLI9Z  
} ~2 T_)l?  
for(int i=0;i<nEndPos.length-1;i++) G-G!c2o  
{ k)'hNk"x  
nEndPos = nStartPos[i+1]; iv?'&IU
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} i6kW"5t  
nEndPos[nEndPos.length-1] = nFileLength; iVd*62$@$  
} yrdJX  
} +o?.<[>!GR  
h.%VWsAO7  
@\i6m]\X  
//启动子线程 HyiuU`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VD,F?L!  
for(int i=0;i<nStartPos.length;i++) 6.6~w\fR8  
{ si/F\NDT
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zpZlA_   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), WnLgpt2G  
nStartPos,nEndPos,i); \u2K?wC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vYL{5,t {1  
fileSplitterFetch.start(); @~ N:F~  
} 4(R O1VWsb  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J@oGAa%3)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); //JF$o=)D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %aaOws  
nEndPos = " + nFileLength); @I]uK[qd  
// fileSplitterFetch[nPos.length-1].start(); ]"dZE2!  
j23OgbI  
n8w|8[uV^  
//等待子线程结束 tRS^|??  
//int count = 0; Gnl6>/L
,  
//是否结束while循环 $9y]>R  
boolean breakWhile = false; k1L GT&  
}Tu_?b`RUm  
@?aNvWeavH  
while(!bStop) x]euNa  
{ zek\AQN  
write_nPos(); #v:<\-MjN  
Utility.sleep(500); 7t\kof  
breakWhile = true; V{HZ/p_Y  
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for(int i=0;i<nStartPos.length;i++) 3! dD!'  
{ j5R= K*y  
if(!fileSplitterFetch.bDownOver) x~$P.X7(~  
{ GLwL'C'591  
breakWhile = false; BXa1[7Z  
break; UIL5K 
 
} 8.o[K  
} Al3Hu-Hf;`  
if(breakWhile) st{:]yTRk  
break; %pc0a^iB  
ve1jLjsB  
XEfTAW#7  
//count++; j*I0]!-  
//if(count>4) J6hWcA6g  
// siteStop(); 1|;WaO1Q  
} ,ZD!Qb  
YM 7P!8Gc  
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System.err.println("文件下载结束！"); 8hQ"rrj+  
} #Q^mdv?  
catch(Exception e){e.printStackTrace ();} Cs^o- g!L  
} PP.k>zsx  
'$ s:cS`=  
(dpBGt@  
//获得文件长度 (+Gd)iO  
public long getFileSize() -njxc{b  
{ vO]gj/SaT  
int nFileLength = -1; R{#-IH="  
try{ oFoG+H"&7\  
URL url = new URL(siteInfoBean.getSSiteURL()); ~NpnRIt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n j; KnZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); n >xhT r<  
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int responseCode=httpConnection.getResponseCode(); x)BG%{h  
if(responseCode>=400) IB}.J,=  
{ n-Dr/c4  
processErrorCode(responseCode); 1Lqs>*  
return -2; //-2 represent access is error 6:v8J1G(<  
} i/C#fIB2  
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String sHeader; aMm`G}9n  
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for(int i=1;;i++) bkmX@+Pe  
{ @`%.\_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k
su:RJ-  
//Utility.log(in.readLine()); /iy2j8:z  
sHeader=httpConnection.getHeaderFieldKey(i); /J/r62  
if(sHeader!=null) H
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{ twf;{lZ(  
if(sHeader.equals("Content-Length")) @*is]d+Ya  
{ xdYjl.f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QdUl-(  
break; M[<O]p6  
} x[WT)  
} 3`^]#Dh  
else U=Z@Ipu5T  
break; %04>R'mN  
} Y +HVn0~qz  
} -<ZzYQk^h  
catch(IOException e){e.printStackTrace ();} tDy1Gh/c  
catch(Exception e){e.printStackTrace ();} RvDqo d  
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Utility.log(nFileLength); +(PtOo.  
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return nFileLength; +ZizT.$&  
} 
{:4); .  
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9nM {x?  
//保存下载信息（文件指针位置） 5Tn4iyg;B  
private void write_nPos() uBl&|yvxB  
{ b.YQN'  
try{ k^R>xV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vk{4:^6.TV  
output.writeInt(nStartPos.length); )byQ=-<1  
for(int i=0;i<nStartPos.length;i++) jG)>{D  
{ g=i|D(".  
// output.writeLong(nPos); {[r'+=}l\S  
output.writeLong(fileSplitterFetch.nStartPos); [C771~BL>  
output.writeLong(fileSplitterFetch.nEndPos); d[TcA2nF
 
} ?xN8HG4  
output.close(); 9 *]Z  
} YH<@->Ip  
catch(IOException e){e.printStackTrace ();} IEC:zmkn  
catch(Exception e){e.printStackTrace ();} eHqf3f   
} yQou8
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t9 &O0tpe  
}pTw$B  
//读取保存的下载信息（文件指针位置） dN\pe@#lKP  
private void read_nPos() $PrzJc  
{
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try{ ,wRrx&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); vaTXu*   
int nCount = input.readInt(); M$! 0ikh  
nStartPos = new long[nCount]; \+cQiN b@  
nEndPos = new long[nCount]; Ls|;gewp  
for(int i=0;i<nStartPos.length;i++) 35&&*$Jm  
{ M{~eI  
nStartPos = input.readLong(); >V;<K?5B`W  
nEndPos = input.readLong(); t{?_]2vl  
} n>#h(  
input.close(); +|#:*GZ  
} BOh&Db*  
catch(IOException e){e.printStackTrace ();} egr@:5QwZ{  
catch(Exception e){e.printStackTrace ();} /JveN8L%  
} YJ1P5u:  
f3v/Y5)  
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private void processErrorCode(int nErrorCode) |d{(&s}  
{ ~PoGuj2wA  
System.err.println("Error Code : " + nErrorCode); 0&5}[9?V'  
} Or_9KX2  
.3ic%u;|D  
JmY"Ja,&  
//停止文件下载 }jIb ^|#CD  
public void siteStop() [oKB1GkA  
{ tH W"eag  
bStop = true; YI\^hP#  
for(int i=0;i<nStartPos.length;i++) -p%=36n  
fileSplitterFetch.splitterStop(); &TK%igL  
4~o\Os+8  
YVs{\1|'  
} 1XHGW=n  
} 9oGsrClH  
//负责部分文件的抓取 sM?DNE^BvW  
**FileSplitterFetch.java Y61E|:fV!  
*/ nG8]c9\Q#  
package NetFox; dFFB\|e;0  
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import java.io.*; q=[0`--cd  
import java.net.*; 0K#dWc}"a  
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public class FileSplitterFetch extends Thread { kkd<CEz2IM  
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String sURL; //File URL g$]9xn#_[  
long nStartPos; //File Snippet Start Position VF[]E0=u6  
long nEndPos; //File Snippet End Position ;{Ovqo|  
int nThreadID; //Thread's ID BF]b\/I  
boolean bDownOver = false; //Downing is over DtZkrj)D/  
boolean bStop = false; //Stop identical pD &\Z~5
T  
FileAccessI fileAccessI = null; //File Access interface Uel*:c  
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+'lfW{E1t  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException hwC3['  
{ ~L}0)FZ\9  
this.sURL = sURL; fx_7B (  
this.nStartPos = nStart; VBd.5YW  
this.nEndPos = nEnd; RrRCT.+E  
nThreadID = id; Z~]17{x0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zL7+HY*3o  
} nR ,j1IUF  
^KlMBKWyB  
 =v8#@$  
public void run() nE/T)[1|  
{ t`Hwq   
while(nStartPos < nEndPos && !bStop) xpSMbX{e  
{ 8ALYih7"W  
*_^AK=i  
nQ/El&{  
try{ o#6j+fo!n  
URL url = new URL(sURL); `qr[0wM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'zpj_QM  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5HJ6[.HO  
String sProperty = "bytes="+nStartPos+"-"; f+F /`P%  
httpConnection.setRequestProperty("RANGE",sProperty); wddF5EcK0  
Utility.log(sProperty); ? 8'4~1g`}  
J#JZ^59lOS  
AQ
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InputStream input = httpConnection.getInputStream(); rZzto;NDS  
//logResponseHead(httpConnection); o"5R^a@  
uK t>6DN.  
6wxQ_Qz:Q  
byte[] b = new byte[1024]; Uh&MoIBs#  
int nRead; 2TIZltFS0e  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &z,w0FOre  
{ fe&K2C%bm  
nStartPos += fileAccessI.write(b,0,nRead); lRentNg0b  
//if(nThreadID == 1) VxsW3*`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r,0> 40^  
} C>j"Ck^<  
X,gXgxP\  

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Utility.log("Thread " + nThreadID + " is over!"); T}fo:aB}  
bDownOver = true; U?@UIhtM|  
//nPos = fileAccessI.write (b,0,nRead); qwVpGNc45  
} ;O.U-s  
catch(Exception e){e.printStackTrace ();} ``zg |h  
} ,.F,]m=  
} uTn(fs)D  
,V|>nkQ  
M22^.,Z  
//打印回应的头信息 ?hmj0i;XC  
public void logResponseHead(HttpURLConnection con) A$%%;O   
{ B_@>HZ\&  
for(int i=1;;i++) 
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{ zvD$N-#`p  
String header=con.getHeaderFieldKey(i); f<y""0L9  
if(header!=null) ,qaIdw[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m]&d TZV  
Utility.log(header+" : "+con.getHeaderField(header)); >JnEhVRQJ9  
else 8R-?x/:  
break; tl0_as  
} \N7 E!
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} b vUYLWzS  
h-#Glse<  
q/&Z6LJ)  
public void splitterStop() +#n[55d  
{ \Mt(9jNK  
bStop = true; i7Y96]  
} MiS$Y  
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} &Du!*V4A  
t;ggc{  
VNA VdP  
/* o6oZk0  
**FileAccess.java g+)T\_#u  
*//文件访问(定位，写) 54tpR6%3p  
package NetFox; N}zQ)]xz+r  
import java.io.*; lq+FH&  
'7wWdq  
}vp\lKP  
public class FileAccessI implements Serializable{ +&Sf$t 1  
?%;)> :3N  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 m#DC;(Pn  
RandomAccessFile oSavedFile; He&dVP  
long nPos; ]<TgBo|  
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public FileAccessI() throws IOException o;-)8
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{ TRX; m|   
this("",0); O@?? NF6G  
} l[rIjyL@  
EPdR-dC^wE  
@S<=Okrlj  
public FileAccessI(String sName,long nPos) throws IOException ezy0m}@  
{ @[.%A;E4  
oSavedFile = new RandomAccessFile(sName,"rw"); 3'*SSZmnOB  
this.nPos = nPos; m9xO& @#vx  
oSavedFile.seek(nPos); O`~T:N|D  
} 36.L1!d)pE  
=U3!D;XP  
H@5:
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public synchronized int write(byte[] b,int nStart,int nLen) )2u=U9  
{ QvjsI;CQ-  
int n = -1; O_(/uLH  
try{ [
@&  
oSavedFile.write(b,nStart,nLen); p@>_1A}qh_  
n = nLen; R\1#)3e0  
} H4Pj 3'  
catch(IOException e) T%?<3/Ev!  
{ n%W~+  
e.printStackTrace (); EKq9m=Ua@o  
} VO[s:e9L  
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return n; uRwIxT2  
} ;lnh;0B  
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} p\1[cz)B  
/dhw~|  
$w#C;2k]N  
/* 8X[G)J;  
**SiteInfoBean.java vvFXdHP  
*/ Kh'/Ne?  
package NetFox; fqFE GyeNr  
)m \}ITf  
J{\S+O2,*  
public class SiteInfoBean { DRj\i6-v  
(/tbe@<  
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private String sSiteURL; //Site's URL BTgL:  
private String sFilePath; //Saved File's Path @T>)fKCg  
private String sFileName; //Saved File's Name \oLRNr[F  
private int nSplitter; //Count of Splited Downloading File b78'yM&  
L:%; Fx2  
$kvF]|<bu  
public SiteInfoBean() Vb|DNl@  
{//nSplitter的缺省值为5 & /UcFB  
//default value of nSplitter is 5 ?L+@?fVN  
this("","","",5); a]BnHLx  
} D />REC^
 
K
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e*Sv}4e=.  
{ )9{?C4NQ  
sSiteURL= sURL; K/ I3r_  
sFilePath = sPath; p!|ok#sW  
sFileName = sName; (,[m}Qb?!  
this.nSplitter = nSpiltter; %AXa(C\1  
$ZH$x3;  
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} G*3O5m  
?)'j;1_=E3  
#ZeZs31  
public String getSSiteURL() q --NLm@;  
{ w<.{(1:v  
return sSiteURL; tB8XnO_c  
} K q: +{'  
H&6lQ30/)  
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public void setSSiteURL(String value) #Kn=Q  
{ 4\Mh2z5  
sSiteURL = value; ?SkYFa`u*  
} Jou~>0,/j  
m .l
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6Z\[{S];  
public String getSFilePath() $._p !,<  
{ ;.'2ZNt2  
return sFilePath; v%VCFJ  
} VSc;}LH  
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public void setSFilePath(String value) 4?jXbC k~x  
{ {~.h;'m  
sFilePath = value; i$?i1z*c}  
} XTXRC$B  
q{[}*%  
?r"m*fY
%  
public String getSFileName() F'|D  
{ k?o(j/  
return sFileName; I)U|~N  
} .ss/E  
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@=E@ *@g  
public void setSFileName(String value) /NNe/7'l  
{ D"El6<3)h  
sFileName = value; 5YQ4]/h  
} <2HI. @^  
q UY;CEf  
4xjk^N9  
public int getNSplitter() vHCz_ FV  
{ Ps4spy0Fp  
return nSplitter; LZqx6~]O  
} ^!3Sz1  
2v0lWO~c7z  
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public void setNSplitter(int nCount) BXiuVx  
{ JVD#wwic  
nSplitter = nCount; B-
N  
} AA:Ch?  
} Z f4Xt Yn  
22a$//}E  
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/* |
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**Utility.java MS%xOB*6  
*/ Q|rrbxb  
package NetFox; DI'wZy
SS^  
NmthvKhH  
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public class Utility { a*0gd-e0@  
m jC6(?V  
wLAGe'GX  
public Utility() Nc()$Nl8  
{ 3ybEQp9  
RAxAy{  
CTv-$7#  
} [RiCa  
.h-:)e*  
//线程睡眠 (
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public static void sleep(int nSecond) B9`nV.a  
{ Ev|2bk \  
try{ mWZoo/xtT  
Thread.sleep(nSecond); Fyrr,#  
} V lN&Lz  
catch(Exception e) RcitW;{|Kg  
{ ;]3Tuq  
e.printStackTrace (); KGS=(z  
} /m%i"kki  
} kep.+t[  
~v$gk  
//日志 Z#IRNFj  
public static void log(String sMsg) 8 C@iD%  
{ ^|5bK_Z&  
System.err.println(sMsg); )s4#)E
1  
} O:"gJ4D  
;]34l."85  
m;)[gF  
public static void log(int sMsg) $/ew'h9q  
{ qP-
*  
System.err.println(sMsg); Ouc=4'$-  
} K]yCt~A$  
} J~9l+?  
yf(VwU, x  
m7Nm!Z7  
/* W]{mEB  
**TestMethod.java J'`,];su  
*/ *D
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package NetFox; /KFCq|;7s,  
sq
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";AM3  
public class TestMethod { LRW7_XYz  
(?Fz{  
yxh8sAZ  
public TestMethod() Z.Z+cFi  
{ ///xx/weblogic60b2_win.exe TXD\i Dq  
try{ V4ml& D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6;i]v|M-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); # kl?ww U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'kPc`)\  
fileFetch.start(); {]]qd!,  
} D'2&'7-sm\  
catch(Exception e){e.printStackTrace ();} E#X(0(A)  
z@iu$DZ  
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} Wg9q
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v>CAA"LH  
4zX@TI>j  
public static void main(String[] args) zL$$G,  
{ z)I.^  
new TestMethod(); #Y`GWT1==  
} Ytop=ZIl'  
} | z=:D*uh~  
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