http断点续传简单实现（java)

/* s3*h=5bX=  
**SiteFileFetch.java lIg;>|'Z5&  
*/ =~i~SG/f  
package NetFox; $Xf gY1S  
import java.io.*; ]iyJ>fC  
import java.net.*; i%8I (F  
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e[HP]$\  
public class SiteFileFetch extends Thread { 4{h?!Z*  
a+TlZE>8  
3JiJ,<,7  
SiteInfoBean siteInfoBean = null; //文件信息Bean 4|Dxyb>pS  
long[] nStartPos; //开始位置 v(?^#C>6W  
long[] nEndPos; //结束位置 06 kjJ4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 cvR|qHNX  
long nFileLength; //文件长度 w a!g/\  
boolean bFirst = true; //是否第一次取文件 MZGN,[~)6  
boolean bStop = false; //停止标志 8,BNs5  
File tmpFile; //文件下载的临时信息 ZqHh$QBD 9  
DataOutputStream output; //输出到文件的输出流 2Rc'1sCth-  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） GoI3hp(  
public SiteFileFetch(SiteInfoBean bean) throws IOException PjriAlxD  
{  nN!/  
siteInfoBean = bean; 9 p6QNDp  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &{${Fq
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^R.kThG  
if(tmpFile.exists ()) >[TB8  
{ 9U1cH qV  
bFirst = false; r8\"'4B1  
read_nPos(); jj^{^,z\  
} C%8nr8po  
else gJn|G#!  
{ d&K2\n  
nStartPos = new long[bean.getNSplitter()]; EU?)AxH^  
nEndPos = new long[bean.getNSplitter()]; sM)qzO2wh  
} 2Qg.b-C  
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} q]F2
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public void run() n"YY:Gm;8  
{ \s
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//获得文件长度 rjzRZ  
//分割文件 J@RhbsZn  
//实例FileSplitterFetch vt0XCUnK  
//启动FileSplitterFetch线程 u
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//等待子线程返回 y
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try{ NoS|lT  
if(bFirst) QixEMX4<  
{ @, v'V!  
nFileLength = getFileSize(); }RX[J0Prq~  
if(nFileLength == -1) yRt]i>  
{ hKP7p  
System.err.println("File Length is not known!"); bdh6ii  
} wi'CBfr'z  
else if(nFileLength == -2) b#;%TbDF  
{ rEwEdyK  
System.err.println("File is not access!"); T
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} X
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else <SeK3@Gi  
{ SV%;w>  
for(int i=0;i<nStartPos.length;i++) 5U)Ia>p  
{ qcau(#I9.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7x8/Vz@\  
} aO:wedfl  
for(int i=0;i<nEndPos.length-1;i++) px6[1'|g  
{ 0XV8B  
nEndPos = nStartPos[i+1]; (]* Ro 8  
} olc7&R  
nEndPos[nEndPos.length-1] = nFileLength; l-` M 9#  
} H4C]%Q  
} *o<zo `  
wLn,x;;<  
)C^ZzmB  
//启动子线程 f' |JLhs  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W Z'UVUi8  
for(int i=0;i<nStartPos.length;i++) [(Z{5gK  
{ l/?Jp+]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JC|j*x(k/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xUT]6T0dB  
nStartPos,nEndPos,i); HCOv<k  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); | Q0Wv8/  
fileSplitterFetch.start(); X>}-UHKV+  
} ZDHm@,d  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [D/q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \NE~k)`4j%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", dk<) \C"  
nEndPos = " + nFileLength); 4%k{vo5i  
// fileSplitterFetch[nPos.length-1].start(); x-0O3IIE  
5d?\>dA  
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//等待子线程结束 .|ZO2MCd  
//int count = 0; [PXv8K%]p  
//是否结束while循环 7$"{&T  
boolean breakWhile = false; 6"@`iY  
3a|I| NP  
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while(!bStop) e`]x?t<U4/  
{ c, IAz  
write_nPos(); IR_&dWHyc  
Utility.sleep(500); P*=M?:Jb,  
breakWhile = true; 4MM
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B!
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for(int i=0;i<nStartPos.length;i++) a]=k-Xh  
{ aK|],L  
if(!fileSplitterFetch.bDownOver) },eV?eGj  
{ ?$v*_*:2h  
breakWhile = false; Qs\m"yx  
break; KE$I!$zO  
} TzSEQS{  
} B>]4NF\)H9  
if(breakWhile) :{8,O-  
break; b8FSVV 7@  
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//count++; wZe>}1t  
//if(count>4) uW 7Yem&  
// siteStop(); {JGXdp:SB  
} K=K]R01/o  
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BV"l;&F[  
System.err.println("文件下载结束！"); }uFV\1  
} (fqU73  
catch(Exception e){e.printStackTrace ();} 3[*x'"Q;H  
} ~pt#'65}:  
Pl/B#Sbf'  
?B{,%2+  
//获得文件长度 Tebu?bj  
public long getFileSize() #Fkn-/nL  
{ !n^7&Y[N;  
int nFileLength = -1; vp|.x |@  
try{ x'iBEm  
URL url = new URL(siteInfoBean.getSSiteURL()); MhDPf]` Gg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y F;KyY{  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4p6\8eytq.  
?{]"UnyVE*  
b O9PpOk+z  
int responseCode=httpConnection.getResponseCode(); {>h,@  
if(responseCode>=400) O5v~wLx9e  
{ H tx)MEZ  
processErrorCode(responseCode); SO+J5,)HA  
return -2; //-2 represent access is error @W.0YU0|J  
} (nnIRN<}$  
__Egr@  
Ae8P'FWB>  
String sHeader; tGwQUn  
f>[!Zi*  
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for(int i=1;;i++) -Gj."ks
  
{ Tqm)-|[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); QI4a@WB]ok  
//Utility.log(in.readLine()); %df[8eX{  
sHeader=httpConnection.getHeaderFieldKey(i); +5N09$f;R  
if(sHeader!=null) ;~"#aL50fe  
{ Gj- *D7X5  
if(sHeader.equals("Content-Length")) rrrn8b6  
{ K!O7q~s[D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5;[h&jH  
break; +nKf ^rG  
} 28,g'k!  
} w1,6%?p(O  
else V_P,~!  
break; v"V?  
} UEH+E&BCC  
} +`+r\*C5  
catch(IOException e){e.printStackTrace ();}
5^e|802  
catch(Exception e){e.printStackTrace ();} JU!vVA_  
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Utility.log(nFileLength); sSsRn*LN-:  
I`[s(C>3@  
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return nFileLength; Pi'[d7o  
} m:C|R-IL  
/F_(
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VN >X/  
//保存下载信息（文件指针位置） +*Pj,+;W  
private void write_nPos() a{4RG(I_  
{ i4\m/&of3y  
try{ -n]E
\"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (6~~e$j  
output.writeInt(nStartPos.length); gB}UzEj^<  
for(int i=0;i<nStartPos.length;i++) (db4.G+0  
{ T)#eaz$4W  
// output.writeLong(nPos); B$&&'i%  
output.writeLong(fileSplitterFetch.nStartPos); 1ZRSeh  
output.writeLong(fileSplitterFetch.nEndPos); nI<Ab_EB  
} PXDwTuyc  
output.close(); BV512+M  
} {+x;J4  
catch(IOException e){e.printStackTrace ();} IWP[?U=  
catch(Exception e){e.printStackTrace ();} &J}w_BFww  
} <"}WpT  
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8~eYN-#W&  
//读取保存的下载信息（文件指针位置） [B"CNnA  
private void read_nPos() K0z@gWGE  
{ $S{]` +  
try{ r^$WX@ t&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [;qZu`n>  
int nCount = input.readInt(); YR
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nStartPos = new long[nCount]; Wz-7oP%;I  
nEndPos = new long[nCount]; h0n,WU/Kw  
for(int i=0;i<nStartPos.length;i++) OVf%m~%&s  
{ N[8y+2SZ  
nStartPos = input.readLong(); 5Q.z#]Lg  
nEndPos = input.readLong(); rhvTV(Bz  
} t*cVDA&K  
input.close(); 6/&aBE=  
} nN[gAM (  
catch(IOException e){e.printStackTrace ();} pi?[jU[Tn  
catch(Exception e){e.printStackTrace ();} IiRII)  
} o7WK"E!pF'  
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private void processErrorCode(int nErrorCode) *d;D~"E<@  
{ {ehAF=C  
System.err.println("Error Code : " + nErrorCode); L!V6Rfy  
} Q^z&;%q1  
%9P)Okq  
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//停止文件下载 )3RbD#?  
public void siteStop()  f]JLFg7  
{ a54qv^IS  
bStop = true; @
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for(int i=0;i<nStartPos.length;i++) X__>r ?oJ  
fileSplitterFetch.splitterStop(); *g;4?_f  
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\4r?=5v*  
} q*B(ZG  
} BO3%p  
//负责部分文件的抓取 BV`,~n:
 
**FileSplitterFetch.java "8|a4Y+F  
*/ r:*0)UZlD  
package NetFox; +~L26T\8  
_6,Tb]  
e$+/;MRq  
import java.io.*; 3Az7urIY  
import java.net.*; !YCus;B~  
5v@-.p  
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public class FileSplitterFetch extends Thread { K)d]3V!  
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String sURL; //File URL uqMe%  
long nStartPos; //File Snippet Start Position WMw]W&  
long nEndPos; //File Snippet End Position O3>m,v  
int nThreadID; //Thread's ID s wIJmA  
boolean bDownOver = false; //Downing is over %oY=.Ok ]  
boolean bStop = false; //Stop identical "\l O1D  
FileAccessI fileAccessI = null; //File Access interface !33)6*s  
F:o<E 42  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2/]74d8  
{ k-uwK-B}v+  
this.sURL = sURL; ~&?{hd.  
this.nStartPos = nStart; n,E=eNc  
this.nEndPos = nEnd; />,Tq!i\4}  
nThreadID = id; _,m|gr,S  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .h;PMY+  
}  c>(`X@KL  
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public void run() h/t{= @ .5  
{ ojA i2uz  
while(nStartPos < nEndPos && !bStop) k]<E1 c/  
{ ?tJyQT  
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v_$'!i$  
try{ Z.]=u(=a  
URL url = new URL(sURL); EGKj1_ml  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #`>46T  
httpConnection.setRequestProperty("User-Agent","NetFox"); .1&~@e%=-  
String sProperty = "bytes="+nStartPos+"-"; P})Iwk|Z  
httpConnection.setRequestProperty("RANGE",sProperty); yl=_ /'*  
Utility.log(sProperty); 7 q%|-`#  
;hsem,C h7  

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InputStream input = httpConnection.getInputStream(); >pVrY; P[  
//logResponseHead(httpConnection); ?y@RE  
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byte[] b = new byte[1024]; DeAi'"&  
int nRead; J9kmIMq-C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W
xi|(}  
{ eoC@b/F4  
nStartPos += fileAccessI.write(b,0,nRead); i"h '^6M1  
//if(nThreadID == 1) WI?iz-,](  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VGVZ`|  
} *f?z$46  
:a 5#yh  
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Utility.log("Thread " + nThreadID + " is over!"); qOusO6  
bDownOver = true; /lC&'hT  
//nPos = fileAccessI.write (b,0,nRead); [^cflmV  
} @-~ )M_  
catch(Exception e){e.printStackTrace ();} ?3{R'Buv]  
} I-fjqo3  
} v[aFSXGj)  
Z=B6fu*  
4@qKML  
//打印回应的头信息 +EmT+$>J  
public void logResponseHead(HttpURLConnection con) P~>E  
{ AX Y.80+  
for(int i=1;;i++) `ehZ(H}  
{ ^k'?e"[gTs  
String header=con.getHeaderFieldKey(i); g=*`6@_=  
if(header!=null) w/L^w50pt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rcC}4mNe  
Utility.log(header+" : "+con.getHeaderField(header)); 3H_mR j9th  
else LEq"g7YH  
break; t Z_ni}  
} hdw-gem{?  
} d,Fj|}S  
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uN:|4/;{&  
public void splitterStop() wIrjWU2  
{ GAZTCkB"  
bStop = true; arCi$:-z@  
} ZfpV=DU  
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} ;B35E!QJ  
^J?ExMu  
%uuh+@/&yz  
/* (1 "unP-  
**FileAccess.java lZY0A#   
*//文件访问(定位，写) KjrUTG0oA  
package NetFox; }!5x1F!  
import java.io.*; [j6EzMN  
fn%Gu s~  
;XJK*QDN  
public class FileAccessI implements Serializable{ N1lhlw6  
tQSj[Yl  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SIJ:[=5!7  
RandomAccessFile oSavedFile; w/8`]q  
long nPos; [-Zp[  
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public FileAccessI() throws IOException wq[\Fb`  
{  T4}SF  
this("",0); U>q&p}z0H  
} \2?p  
)Ir_:lk  
ZS&n,<a5L}  
public FileAccessI(String sName,long nPos) throws IOException ?4X8l@fR  
{ HT]v S}s  
oSavedFile = new RandomAccessFile(sName,"rw"); |G2hm8 Y  
this.nPos = nPos; @/S6P-4  
oSavedFile.seek(nPos); =j)y.
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} hjuzVOE|W  
 #RE  
U=?hT&w\S  
public synchronized int write(byte[] b,int nStart,int nLen) OH.Re6Rr  
{ 4Xna}7  
int n = -1; 9n$0OH /q  
try{ `w_?9^7mH  
oSavedFile.write(b,nStart,nLen); =)56]ki}  
n = nLen; DzZ)aE  
} < q6z$c)K  
catch(IOException e) Km~\^(a '  
{ |!r.p_Zt  
e.printStackTrace (); n-h2SQl!  
} traJub  
+O<0q"E  
N4 O'{  
return n; oB9t&yM  
} <Sxsmf0"  

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} V\ud4  
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],*^wQ
 
/* $9GRAM.  
**SiteInfoBean.java fvajNP  
*/ 2.I'`A  
package NetFox; =-M)2&~L~  
Zk+J=Cwq}  
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public class SiteInfoBean { |aiP7C  
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private String sSiteURL; //Site's URL 2 }QD>  
private String sFilePath; //Saved File's Path `{g8A P3  
private String sFileName; //Saved File's Name Z+!3m.q  
private int nSplitter; //Count of Splited Downloading File !B==cNq  
/Kmzi9j+  
^(ks^<}  
public SiteInfoBean() I*e85wef  
{//nSplitter的缺省值为5 h+mM  
//default value of nSplitter is 5 bl|k6{A  
this("","","",5); *|n::9  
} }?,Gn]]  
gY AXUM,  
~L!*p0dS^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Lm<"W_  
{ T`g.K6$b
 
sSiteURL= sURL; IxT[1$e  
sFilePath = sPath; DXlP(={*  
sFileName = sName; %H:uE*WZ  
this.nSplitter = nSpiltter; q<>  
q!#e2Dx  
s8| =1{  
} 6JWCB9$4  
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[h8j0Q@Q  
public String getSSiteURL() ./@!k[  
{ w]n20&  
return sSiteURL; hR3lo;'  
} -UaUFJa8K&  
D%v4B`4ua'  
X>mY`$!/  
public void setSSiteURL(String value) NLFSw  
{ $ WAFr  
sSiteURL = value; 27*u^N*z@  
} Y)Y`9u<?  
kVs'>H@FY  
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public String getSFilePath() &
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{ @cPb*  
return sFilePath; 2Yt#%
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} >ir'v5  
(OT /o&cQ  
I|lz;i}$  
public void setSFilePath(String value) Z%~j
)  
{ [-!   
sFilePath = value; M}NmA  
} I%^Ks$<"  
*,hS-  
*@fR36  
public String getSFileName() N+x0"~T}I  
{ Vu '/o[nF>  
return sFileName; \B"5 Kp<  
} ?P[uf  
an^"_#8DA@  
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public void setSFileName(String value) Q=
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{ O{a<f7 W  
sFileName = value; N-|E^XIV  
} !s#25}9zX5  
. $uvQpyh  
%)T>Wn%b]v  
public int getNSplitter() S?nk9T+  
{ E%OY7zf`%  
return nSplitter; G$pTTT6#  
} s42M[BW]  
F<
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public void setNSplitter(int nCount) 84^'^nd  
{ PE3FuJGz  
nSplitter = nCount; A<l8CWv[  
} PVH
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} K: g_M  
l T~RH0L  
tAFKq>\  
/* :8aa#bA  
**Utility.java O,R5csMh  
*/ $X8(OS5d'  
package NetFox; z+I'N4*^  
,gGIkl&  
[2?|BUtD[  
public class Utility { dfY(5Wc+f  
yQE|FbiA  
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public Utility() L;zwqdI  
{ fe PH=C  
^Gt&c_gH  
-SZXUN  
} %jz]s4u$5j  
P8!ON=  
//线程睡眠 koOkm:(,  
public static void sleep(int nSecond) +\g/KbV7  
{ sC >_ulkoa  
try{ /aS=vjs  
Thread.sleep(nSecond); K ;\~otR^  
} rD=8O#m g  
catch(Exception e) ^hq+ L^$^  
{ {y)O?9q  
e.printStackTrace (); u3 k%  
} j8n_:;i*  
} fB^h2  
,Y *unk<S  
//日志 HT&CbEa4'  
public static void log(String sMsg) 8G$ %DZ $  
{ Z(DCR/U=(>  
System.err.println(sMsg); 4x7(50hp#  
} p3>(ZWPNV  
sd4eJ  
k(LZ,WSR  
public static void log(int sMsg) 1o"/5T:S[  
{ S(NH# ^  
System.err.println(sMsg); AGaM &x=  
} c%1k'Q  
} .Zo%6[X  
{UqSq  
X&C&DTB  
/* l-s%3E3  
**TestMethod.java EUBJnf:q  
*/ >,c$e' h  
package NetFox; )Z6bMAb0'N  
(w4w  
t^_0w[  
public class TestMethod { +c)"p4m  
7AwV4r*:  
?%RAX CK  
public TestMethod() OAigq6[,  
{ ///xx/weblogic60b2_win.exe y?=W  
try{ ]vj.s/F~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); NUxOU>f  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -CV_yySc  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %=p:\+`VI  
fileFetch.start(); qHwHP 1  
} &6]+a4  
catch(Exception e){e.printStackTrace ();} 5x$/.U  
(EW<Ggi  
2_S%vA<L  
} b1+6I_u.  
/zt9;^e  
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public static void main(String[] args) j@chSk"K  
{ a[e&O&Z  
new TestMethod(); ku2gFO  
} TtZZjeg+V  
} >L5fc".  
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