http断点续传简单实现（java)

/* j{VxB  
**SiteFileFetch.java R4
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*/ wX#\\Jgi  
package NetFox; :L:;~tK  
import java.io.*; dp)lHBV  
import java.net.*; "$0f.FO:i  
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public class SiteFileFetch extends Thread { 7bsW7;C  
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SiteInfoBean siteInfoBean = null; //文件信息Bean SKLQAE5  
long[] nStartPos; //开始位置 >ID 3oi
  
long[] nEndPos; //结束位置 ui9gt"qS`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,)]ZD H  
long nFileLength; //文件长度 dmlh;Z  
boolean bFirst = true; //是否第一次取文件 I_pA)P*Q(6  
boolean bStop = false; //停止标志 nkhM1y  
File tmpFile; //文件下载的临时信息 ]qVJ>  
DataOutputStream output; //输出到文件的输出流 ip>dHj z  
::TUSz2/2  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G^2"\4R]p  
public SiteFileFetch(SiteInfoBean bean) throws IOException klch!m=d  
{ yv'rJI~ Ps  
siteInfoBean = bean; P?0b-Qr$a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v>nJy~O]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); MfL q h  
if(tmpFile.exists ()) D 'u+3  
{ omRd'\ RO  
bFirst = false; n[iil$VKh  
read_nPos(); ^mz_T+UOe  
} hD$U8~zK  
else  (K?[gI  
{ 9J|YP}%  
nStartPos = new long[bean.getNSplitter()]; N%?o-IY  
nEndPos = new long[bean.getNSplitter()]; JI*ikco-  
} be764do  
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} 
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public void run() .{;!bw
 
{ m0* B[  
//获得文件长度 zo5.}mr+  
//分割文件 N1Z8I:  
//实例FileSplitterFetch }?~uAU-  
//启动FileSplitterFetch线程 `kv$B3  
//等待子线程返回 7E5Dz7  
try{ 6P~"7k  
if(bFirst) F@*lR(4C  
{ 'H'+6 
 
nFileLength = getFileSize(); ~ghz%${`  
if(nFileLength == -1) '-S&i{H  
{ Y1'.m5E  
System.err.println("File Length is not known!"); w@ 5/mf?  
} =zjUd 5  
else if(nFileLength == -2) cMWO_$  
{ D{4hNO  
System.err.println("File is not access!"); ,1[
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} LA?\~rh!  
else {e%abr_B  
{ tN{t-xUgk  
for(int i=0;i<nStartPos.length;i++) !TOi]`vqc  
{
$.N~AA~0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +.lWck  
} QP[a^5;Tt  
for(int i=0;i<nEndPos.length-1;i++) (K6`nWk2  
{ $048y X 7M  
nEndPos = nStartPos[i+1]; c9uT`h  
} ~0-764%  
nEndPos[nEndPos.length-1] = nFileLength; Inc:t_  
} |3s&Y`x-D  
} P082.:q"  
=[K)<5,@  
i f<<lq  
//启动子线程 $uw+^(ut  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; M#cr*%  
for(int i=0;i<nStartPos.length;i++) `MsYgd  
{ 9J7J/]7f  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'n[+r}3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vzcBo%  
nStartPos,nEndPos,i); \`/E !ub  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nheU~jb  
fileSplitterFetch.start(); V`\f+Uu  
} o? i.v0@!K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XU_,Z/Yw_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'dc+M9u)_q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", i.t9jN  
nEndPos = " + nFileLength); $}nh[@  
// fileSplitterFetch[nPos.length-1].start(); DMQNr(w{!2  
A6N~UV*_  
q9^Y?`  
//等待子线程结束 l Io9,K
e  
//int count = 0; 0+}EA[  
//是否结束while循环 DD!MGf/  
boolean breakWhile = false; ]
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dP$8JI{  
/5Zp-Pq  
while(!bStop) =#i4MXRZ{  
{ :8^M
5}  
write_nPos(); b96t0w!cs  
Utility.sleep(500); [ WV@w  
breakWhile = true; R"U/RS  
+@emX$cFV  
x&C%4Y_]  
for(int i=0;i<nStartPos.length;i++) \3Dk5cSDk+  
{ C8IkpAD  
if(!fileSplitterFetch.bDownOver) CmEpir{}(  
{ Oj4v#GK]  
breakWhile = false;
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break; n(g)UNx  
} opsQn\4DZ?  
} Cye T]y  
if(breakWhile) l)4O .*  
break; wV(AT$  
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//count++; TZ[Zm  
//if(count>4) HcRa`Sfc]/  
// siteStop(); UuU/c-.  
} U-i.(UyZ  
7kKuZW@K-  
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System.err.println("文件下载结束！"); XZ`:wmc|  
} E<tK4?i"  
catch(Exception e){e.printStackTrace ();} 07V8;A<,  
} E<>*(x/\e  
"#yJHsu]  
j~;;l!({i  
//获得文件长度 MJ`N,E[  
public long getFileSize() ='Q{R*u  
{ ~ 3^='o  
int nFileLength = -1; /kgeV4]zR  
try{ (a@?s$LG  
URL url = new URL(siteInfoBean.getSSiteURL()); ?+~cA^-3T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~e `Bq>  
httpConnection.setRequestProperty("User-Agent","NetFox"); {Z> M  
9T7e\<8"vC  
$<nCXVqL,  
int responseCode=httpConnection.getResponseCode(); Xd<t5{bD!  
if(responseCode>=400) Kv37s0|g  
{ nOb?-rR  
processErrorCode(responseCode); ?^i1_v7 Bi  
return -2; //-2 represent access is error hoM|P8 }rh  
} =^&%9X  
n(1')?"mA  
MZ
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String sHeader; ,E;;wdIt  
J@_ctGv  
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for(int i=1;;i++) POAw M  
{  /ASaB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )w h%|  
//Utility.log(in.readLine()); yF13Of^l./  
sHeader=httpConnection.getHeaderFieldKey(i); Es5f*P0  
if(sHeader!=null) |TsE-t*E}  
{ M;w?[yEZ  
if(sHeader.equals("Content-Length")) $P z`
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{ ({r*=wAP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1MlUG5  
break; >Fio;cn?  
} vhbDb)J  
} gTl<wo +  
else Zxr!:t7  
break; /1N6X.Zb  
} 5|3e&  
} v ^[39*8  
catch(IOException e){e.printStackTrace ();} Snp|!e  
catch(Exception e){e.printStackTrace ();} [.se|]t7X  
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Utility.log(nFileLength); S$
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return nFileLength; F, U*
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} oFOnjK"|F  
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;&H4u)  
//保存下载信息（文件指针位置） dJ$"l|$$  
private void write_nPos() YK|bXSA[  
{ %%(R@kh9  
try{ AT5aDEb^^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &89oO@5  
output.writeInt(nStartPos.length); /x3/Ubmz~x  
for(int i=0;i<nStartPos.length;i++) q^6+!&"  
{ {BKl`1z  
// output.writeLong(nPos); GF3/RT9  
output.writeLong(fileSplitterFetch.nStartPos); Z@hD(MS(C  
output.writeLong(fileSplitterFetch.nEndPos); OyqNLR  
} ~c6}
 
output.close(); ?yh}/T\qp  
} ou %/l4dC  
catch(IOException e){e.printStackTrace ();} }NsUnbxT  
catch(Exception e){e.printStackTrace ();} .^b;osAU  
} 9cJH"  
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//读取保存的下载信息（文件指针位置） ;E'"Ks[GH  
private void read_nPos() 41fJ%f` G  
{ O:da-xWJ  
try{ !~h}8'a?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ux+Q  
int nCount = input.readInt(); {aM<{_v  
nStartPos = new long[nCount]; w^]6w\p  
nEndPos = new long[nCount]; 'TAUE{{  
for(int i=0;i<nStartPos.length;i++) J+f!Ar  
{ 8iekEG$H  
nStartPos = input.readLong(); pAk/Qxl3eo  
nEndPos = input.readLong(); i<(Xr  
} YZ+RWu9K  
input.close(); B4]`-mahO  
} M'!U<Y -  
catch(IOException e){e.printStackTrace ();} u!:z.RH8n  
catch(Exception e){e.printStackTrace ();} JCW\ *R  
} O2"gj"D  
pD&&l!i&[  
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private void processErrorCode(int nErrorCode) *cO sv  
{ -J^(eog[6  
System.err.println("Error Code : " + nErrorCode); Jnv@.  
} [{X^c.8G)  
|^9BA-nA  

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//停止文件下载 ".dZn6"mI  
public void siteStop() `CeJWL5{  
{ ;@ [ 0x  
bStop = true; C.kxQ<  
for(int i=0;i<nStartPos.length;i++) e${>#>  
fileSplitterFetch.splitterStop(); mR;qMX)0h  
#6!52  
,hVvve,j}  
} KzQ3.)/q  
} =tU{7i*+  
//负责部分文件的抓取 a {ab*tM  
**FileSplitterFetch.java fo4.JyBk  
*/ n$[f94d=  
package NetFox; )z8!f}:De=  
]x&u`$F  
76vy5R(.  
import java.io.*; xF8}:z0  
import java.net.*; }$\M{#C~  
Iyo@r%I  
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;
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public class FileSplitterFetch extends Thread { *UW=M
dt  
Z@gnsPN^r  
~}ET?Q7t  
String sURL; //File URL T}3v(6ew4  
long nStartPos; //File Snippet Start Position L^^4=ao0  
long nEndPos; //File Snippet End Position 3
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int nThreadID; //Thread's ID tb?YLxMV  
boolean bDownOver = false; //Downing is over S^Au#1e   
boolean bStop = false; //Stop identical B??J@+Nf  
FileAccessI fileAccessI = null; //File Access interface OUP?p@%]<  
z>R#H/h+  
0hZ1rqq8C  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8[ry|J  
{ YD
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this.sURL = sURL; m=qOg>k  
this.nStartPos = nStart; 0uCT+-  
this.nEndPos = nEnd; ^6p'YYj"5  
nThreadID = id; <Q<+4Y{R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 n
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}  8RwX=  
Kt#,]]  
}jSj+*  
public void run() Ml>( tec
 
{ T@^]i&  
while(nStartPos < nEndPos && !bStop) 1px\K8  
{ ^;F{)bmu+)  
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try{ 0=v{RQ;W4  
URL url = new URL(sURL);  +f4W"t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D&hqV)d4R  
httpConnection.setRequestProperty("User-Agent","NetFox"); #G3N(wV3  
String sProperty = "bytes="+nStartPos+"-"; 9h
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httpConnection.setRequestProperty("RANGE",sProperty); ZEbL
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Utility.log(sProperty); |kiJ}oy  
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cQpnEO&SL  
InputStream input = httpConnection.getInputStream(); (*l2('e#@  
//logResponseHead(httpConnection); oUW<4l  
:
cp   
/c+)C"  
byte[] b = new byte[1024]; <xS=#  
int nRead; dGgP_S  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @Z\2*1y6  
{ p {%t q$}.  
nStartPos += fileAccessI.write(b,0,nRead); 9(VRq^Z1  
//if(nThreadID == 1) |Svk^mq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _C+DBA  
} ^Qh-(u`  
LR$z0rDEM  
! sYf<  
Utility.log("Thread " + nThreadID + " is over!"); 0P 5BArJ?  
bDownOver = true; UxPGv;F  
//nPos = fileAccessI.write (b,0,nRead); jL4>A$  
} V;[p438o  
catch(Exception e){e.printStackTrace ();} _p4}<pG  
} $N.`)S<  
} 0o68rF5^s  
X!0kK8v  
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//打印回应的头信息 Tt6{WDscZ  
public void logResponseHead(HttpURLConnection con)
#J~Xv:LgD  
{ |B|@GF?:  
for(int i=1;;i++) C >kmIw'  
{ _@|fva&s,;  
String header=con.getHeaderFieldKey(i); ,9UCb$mh  
if(header!=null) 4@~a<P#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %LcH>sV  
Utility.log(header+" : "+con.getHeaderField(header)); KZ4zF  
else G:hU{S7  
break; fn?VNZ`J  
} \CtQ*[FmN  
} 4[_L=zD  

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;&7,73!  
public void splitterStop() uA
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{ EJ8I[(  
bStop = true; aYBTrOdz  
} To^# 0  
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,$PFI(Whk  
} [lOf|^9  
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+0U#.|?  
/* c G*(C
  
**FileAccess.java NWb} OXK/  
*//文件访问(定位，写) v7L"`  
package NetFox; 487YaioB$  
import java.io.*; pFEZDf}:  
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di--:h/  
public class FileAccessI implements Serializable{ -}E)M}W  
b~jIv:9T  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 abL/Y23 "  
RandomAccessFile oSavedFile; 'YBi5_  
long nPos; Xthtw*  
B
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public FileAccessI() throws IOException ;*W=c  
{
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this("",0); T<f2\q8Uo=  
} A%h~Z a  
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public FileAccessI(String sName,long nPos) throws IOException D!X>O}
  
{ nDyvX1]  
oSavedFile = new RandomAccessFile(sName,"rw"); yQ8M >H#J  
this.nPos = nPos; "|F.'qZrm  
oSavedFile.seek(nPos); {cmo^~[L$  
} jo<>Hc{g>  
/.7$`d  
]vRVo6@ k  
public synchronized int write(byte[] b,int nStart,int nLen) C5>{Q:.`e'  
{ 5woIGO3X  
int n = -1; D}mo\  
try{ >sn"  
oSavedFile.write(b,nStart,nLen); 2IKxh  
n = nLen; A *a{  
} 4\&H?:c.  
catch(IOException e) 38"8,k  
{ M\:"~XW  
e.printStackTrace (); =_#ye}E  
} Xulh.:N}  
o%kSR ]V|  
.a 'ETNY:>  
return n; @qg0u#k5  
} /V#MLPA  
NTv#{7q  
/ e~  
} R*JOiVAC  
h#(.(
d  
')C_An>X6  
/* \GjXsR*b5  
**SiteInfoBean.java htdn$kqG   
*/ w]]x[D]L  
package NetFox; zJB+C=]D7H  
J@u!S~&r  
3L 1lq .  
public class SiteInfoBean { 'W<a54T?z  
)_x8?:lv  
h=p-0 Mx .  
private String sSiteURL; //Site's URL _js2^<7v}  
private String sFilePath; //Saved File's Path 2uI`$A:  
private String sFileName; //Saved File's Name mCEKEX  
private int nSplitter; //Count of Splited Downloading File oKMg7 3*  
'vf,T4uQ"  
@=aq&gb  
public SiteInfoBean() 2WbZ>^:Nsk  
{//nSplitter的缺省值为5 skmDsZzw  
//default value of nSplitter is 5 P)o[p(  
this("","","",5); t6U+a\-<  
} $EHn;~w T  
w}KcLa
I  
0i1?S6]d-  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b*%WAVt2T  
{ ?9.?w-Q'  
sSiteURL= sURL; 5<'Jd3N{&  
sFilePath = sPath; (h(ZL9!  
sFileName = sName; KgkB)1s@n  
this.nSplitter = nSpiltter; <8}9s9Nk  
oGjYCV
c  
="Pyw
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} !QzMeN;D  
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9bYHb'70  
public String getSSiteURL() \V7x3*nA  
{ Q0cf]  
return sSiteURL; D2mAyU-  
} oFA$X Y  
63\>MQcLy  
Y-9j2.{  
public void setSSiteURL(String value) u>@G:kt8  
{ eHIC'b.  
sSiteURL = value; xrd^vE  
} =i<(hgD  
9a,CiH%@  
G9%4d;uFT  
public String getSFilePath() oDK\v8w-  
{ =-Tetp  
return sFilePath; >eI(M $  
} qN(;
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6FAP *V;  
public void setSFilePath(String value) NyN
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{ Ml ^Tb#  
sFilePath = value; H%V[% T4=  
} ".=EAXVU  
\`&fr+x  
ru L
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public String getSFileName()  }P#gXG  
{ L x&ZWF$  
return sFileName; +g&W423k_  
} xR3A4m  
4kEFbzwx  
~b/>TKn+  
public void setSFileName(String value) bv0 %{u&  
{ W1z5|-T  
sFileName = value; V2X(f6v  
} Uyh#g^r  
YXEZ&$e'  
kzT'  
public int getNSplitter() |ouk;r24V  
{  ?auiq  
return nSplitter; Z^3Risi  
} |iI`p-L9  
U;/ )V  
y{<7OTA)  
public void setNSplitter(int nCount) FdD'H
p+  
{ mdd~B2"el  
nSplitter = nCount; TCVJ[LbJ  
} ?h{&  
} /q=<OEC  
h:|aQJG5  
j
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/* O_E[FE:+  
**Utility.java mGIS[_dcs  
*/ +2vcUy  
package NetFox; @A:Xct  
$+tkBM  
3h4>edM  
public class Utility { g;-CAd5  
*_ "j"{  
4FYws5]$  
public Utility() Uu G
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{ )0NA*<Q+.  
B$fL);l-  
/vBpRm  
} MQhL>oQ  
9[/Gd{`XC  
//线程睡眠 jytfGE:  
public static void sleep(int nSecond) Y*J,9  
{ Y
8(g8RN  
try{ @va6,^)  
Thread.sleep(nSecond); #VtlXr>G  
} _.zW[;84b  
catch(Exception e) F?3a22Zg#  
{ !DXKn\aQf  
e.printStackTrace (); jf@#&%AC9  
} V9][a  
} @32JMS<  
>$k_tC'"  
//日志 YEQ}<\B\&  
public static void log(String sMsg) 0fwo8NgX  
{ }3ty2D#/:  
System.err.println(sMsg); :(N3s9:vz  
} [{L4~(uU8  
X^7bOFWE  
wYPJji D  
public static void log(int sMsg) Sm{idky)[  
{ b1R%JY7/S  
System.err.println(sMsg); H4MFTnJ{  
} 5fjmr  
} `qb
f_;\  
|#^wYZO1U  
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/* W1dpKv  
**TestMethod.java $WED]X@X!  
*/ MqDz cB]  
package NetFox; P-o/ax  
;'~U5Po8  
*](maF~%C  
public class TestMethod { mnh>gl!l  
&mXJL3iN  
(NR8B9qLN  
public TestMethod() XHKiz2Pc1  
{ ///xx/weblogic60b2_win.exe M=:!d$c  
try{ ux`)jOQ`Y]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); c5C 2xE}T  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); VbyGr~t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3lr9nBR  
fileFetch.start(); ^EtBo7^t  
} 8[v9|r  
catch(Exception e){e.printStackTrace ();} eV(nexE  
:DWvH,{+&  
q~:H>;:G-  
} 6="Qwrk  
[Ey[A|g  
<e&88{jJ  
public static void main(String[] args) J:D{5sE<|  
{ G42J  
new TestMethod(); _L8|ZV./  
} X 8/9x-E_  
} &BOq%*+  
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