http断点续传简单实现（java)

/* 1`t?5|s>  
**SiteFileFetch.java ?X1#b2s  
*/ r;C\eN  
package NetFox; x
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import java.io.*; {;E/l(HNI  
import java.net.*; (?!0__NN;  
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public class SiteFileFetch extends Thread { GP$Y4*y/  
#77UKYj2L-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g@k9w{_  
long[] nStartPos; //开始位置 D2p6&HNT  
long[] nEndPos; //结束位置 u2<h<}Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 hl:eF:'hm  
long nFileLength; //文件长度 4QNR_w
  
boolean bFirst = true; //是否第一次取文件 ->8q, W2A  
boolean bStop = false; //停止标志 px
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File tmpFile; //文件下载的临时信息 l'T0<  
DataOutputStream output; //输出到文件的输出流 p#d UL9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） j%;)CV G"  
public SiteFileFetch(SiteInfoBean bean) throws IOException F21[r!3  
{ ZL</  
siteInfoBean = bean; ([*t.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); DcA'{21  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~S6{VK.  
if(tmpFile.exists ()) @E2nF|N  
{ ?m1$*j  
bFirst = false; ]LTc)[5Zj  
read_nPos(); <h=M Rw,l  
} ?<'W~Rm6n  
else % eRwH >  
{ 29^bMau)v  
nStartPos = new long[bean.getNSplitter()]; 3L?a4,Q"k}  
nEndPos = new long[bean.getNSplitter()]; GuWBl$|+b  
} 5-HJ&Q
 
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} Pfx71*u,  
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public void run() o(/ia3  
{ o$VH,2 QF  
//获得文件长度 >;v0zE  
//分割文件 ;|QR-m2/  
//实例FileSplitterFetch `YNC_r#tG  
//启动FileSplitterFetch线程 ;/ KF3 %  
//等待子线程返回 gc3 U/ jM  
try{ OeGuq.>w  
if(bFirst) B:4qW[U#  
{ ~^~RltY  
nFileLength = getFileSize(); ZHlin#"  
if(nFileLength == -1) \)Z
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{ t[,T}BCy.  
System.err.println("File Length is not known!"); ddDJXk)!0  
} Y&f[2+?2NK  
else if(nFileLength == -2) 3b@1Zahz  
{ jA4v?(AO}#  
System.err.println("File is not access!"); $L8s/1up  
} K)UOx#xe1  
else "!6~*!]c  
{ Y0O<]2yVx  
for(int i=0;i<nStartPos.length;i++) y~c[sW  
{ ptyDv  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); H)T# R?  
} 1r& ?J.z25  
for(int i=0;i<nEndPos.length-1;i++) OCO,-
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{ ' 5 
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nEndPos = nStartPos[i+1]; B4Af  
} \w[ZY$/  
nEndPos[nEndPos.length-1] = nFileLength; Z?c=t-yqp  
} X1[R*a/p  
} JS?l?~  
[pgkY!R?)  
":#x\;  
//启动子线程 w^E]N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GdeR#%z  
for(int i=0;i<nStartPos.length;i++) Bj($_2M%+  
{ a 8hv.43  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (Zn3-t*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q\y#  
nStartPos,nEndPos,i); Y_3YO2K]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A;j$rGx  
fileSplitterFetch.start(); FJ,\?ooGf  
} *5'6E'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q0uO49sg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pD_eo6xX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |DPpp/  
nEndPos = " + nFileLength); _&Uo|T  
// fileSplitterFetch[nPos.length-1].start(); T{{AZV"pB  
MY*>)us\  
+6)kX4  
//等待子线程结束 2j/1@Z1j=  
//int count = 0; &Yks,2:P  
//是否结束while循环 7U )qC}(  
boolean breakWhile = false; xKLcd+hCZ  
i =fOdp  
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while(!bStop) u:H 3.5)%  
{ }V#9tWW  
write_nPos(); i~Ob( YIH  
Utility.sleep(500); 2N8sq(LK{  
breakWhile = true; ^@LhUs>3  
\ NSw<.  
~v(M6dz~vk  
for(int i=0;i<nStartPos.length;i++) 3g#=sd!0O@  
{ IfmIX+t?  
if(!fileSplitterFetch.bDownOver) 9Bvn>+_K  
{ C`~4q<W'  
breakWhile = false; F;&fx(  
break; sEJ;t0.LX  
} -anFt+f-  
} dYew7  
if(breakWhile) (zro7gKked  
break; ?r'TH/>  
(VXx G/E3  
-k[tFBlw  
//count++; e5>5/l]jsg  
//if(count>4) ':2*+
 
// siteStop(); U>B5LU9&  
} k5%0wHpk=  
xBE RCO^  
UFIAgNKl  
System.err.println("文件下载结束！"); D7_Hu'y<o  
} Jn@Mbl  
catch(Exception e){e.printStackTrace ();} cwWSNm|  
} 5)n:<U*  
W "\tkh2  
vz#wP  
//获得文件长度 Zc\h15+P  
public long getFileSize() 0O['
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{ vD)A)  
int nFileLength = -1; T.
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try{ $L&9x3+?Kg  
URL url = new URL(siteInfoBean.getSSiteURL()); $7gB&T.x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vLK\X$4  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;]oXEq`  
q%kj[ZOY$]  
7MuK/q.  
int responseCode=httpConnection.getResponseCode(); o!l3.5m2d  
if(responseCode>=400) Xm^h5jAr  
{ Eagmafu  
processErrorCode(responseCode); B-ri}PA  
return -2; //-2 represent access is error G_,t\  
} ?m9UhLeaS=  
Va/@#=,q]  
K,C$J I  
String sHeader; ^2;(2s  
pW3)Y5/D  
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for(int i=1;;i++) 1l|A[G  
{ ;LF)u2x=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F<ocY0=9p  
//Utility.log(in.readLine()); fCt\2);a  
sHeader=httpConnection.getHeaderFieldKey(i); .iP G/e  
if(sHeader!=null) M8",t{7  
{ & L.PU@  
if(sHeader.equals("Content-Length")) _^xh1=Qr}n  
{ X.T\=dm%v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =
6Kv`  
break; =S[FJaIu7  
} rMXOwkE  
} /!{A=N
  
else +Sdx8 Z5  
break; =FD`A#\C~  
} ReB(T7Vk=  
} 4Fr7jD,#k  
catch(IOException e){e.printStackTrace ();} Q&.IlVB[  
catch(Exception e){e.printStackTrace ();} iQm.]A  

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Utility.log(nFileLength); _sf#J|kQ  
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return nFileLength; mOz&6T<|  
} p'%: M  
V$Xl^#tN  
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//保存下载信息（文件指针位置） lEyG9Xvi  
private void write_nPos() WK_y1(v>  
{ X
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try{ %g]$Vfpy  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?LV-W  
output.writeInt(nStartPos.length); B::4Qme  
for(int i=0;i<nStartPos.length;i++) LpiHoavv  
{ 7$1fy0f[l  
// output.writeLong(nPos); #E$Z[G]  
output.writeLong(fileSplitterFetch.nStartPos); a$xeiy9  
output.writeLong(fileSplitterFetch.nEndPos); iKF$J3a\2f  
} I", &%0ycm  
output.close(); iBtjd`V*  
}  [`hE^chd  
catch(IOException e){e.printStackTrace ();} {#w A!>.  
catch(Exception e){e.printStackTrace ();} 6m-:F.k1(  
} q2S!m6!  
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|Uy e>%*}4  
//读取保存的下载信息（文件指针位置） :Er^"9'A2  
private void read_nPos() :!+}XT7)/  
{ u^aFj%}]L  
try{
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]e@0T{!  
int nCount = input.readInt(); !e:iB7<  
nStartPos = new long[nCount]; {;Y 89&*R  
nEndPos = new long[nCount]; k"q!|+&Fs  
for(int i=0;i<nStartPos.length;i++) E
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{
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nStartPos = input.readLong(); QX/X {h6  
nEndPos = input.readLong(); S/nj5Lh  
} ;LQ# *NjL\  
input.close(); l\T!)Ql  
} PkPDVv  
catch(IOException e){e.printStackTrace ();} &*G5J7%w  
catch(Exception e){e.printStackTrace ();} J8u{K.(*7  
} m?D <{BQ;  
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private void processErrorCode(int nErrorCode) .)"_Q/q  
{ S1 EEASr!}  
System.err.println("Error Code : " + nErrorCode); [5?4c'Ev  
} Q)LXL.0h  
tb:,Uf>E  
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//停止文件下载 E-yT  
public void siteStop() O6m.t%*  
{ L25kh}Q#7  
bStop = true; yqC Q24  
for(int i=0;i<nStartPos.length;i++) YGq=8p7.R  
fileSplitterFetch.splitterStop(); ;~Q  
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} 7Sg
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} b 0LGH. z4  
//负责部分文件的抓取 DU5:+" u3  
**FileSplitterFetch.java KP[NuXA`  
*/ GI2eJK  
package NetFox; j4~7akG  
m,W) N9 M  
>lD;0EN  
import java.io.*; 7BL|x  
import java.net.*; Q00R<hu@F  
Vs#"SpH{'  
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public class FileSplitterFetch extends Thread { B ~fSMB6h  
csH2_+uG  
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String sURL; //File URL 0bMoUy*q  
long nStartPos; //File Snippet Start Position doP$N3Zm  
long nEndPos; //File Snippet End Position v! 7s M  
int nThreadID; //Thread's ID _GVE^yW~z  
boolean bDownOver = false; //Downing is over U@Z>/ q  
boolean bStop = false; //Stop identical nNt*} k  
FileAccessI fileAccessI = null; //File Access interface f4]N0  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0HGlf  
{ [8>z#*B  
this.sURL = sURL; BdN8 ^W  
this.nStartPos = nStart; :83,[;GO2  
this.nEndPos = nEnd; ,Bisu:v6FW  
nThreadID = id; ?e F@Q!h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )v[XmJ>H~o  
} 8F#osN  
63W{U/*aao  
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public void run() 2t+D8 d|c<  
{ Fi mN?s  
while(nStartPos < nEndPos && !bStop) >_XOc  
{ >[ eW">:>K  
')B =|T)  
>T<6fpXuk2  
try{ \|CPR6I  
URL url = new URL(sURL); 10p8|9rE}B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6cJ<9i &  
httpConnection.setRequestProperty("User-Agent","NetFox"); ` ^DjEdUN  
String sProperty = "bytes="+nStartPos+"-"; rwiw Rh  
httpConnection.setRequestProperty("RANGE",sProperty);  %BUEX  
Utility.log(sProperty); _ Yfmxn8V  
3Jk[/.h  
H&M1>JtE  
InputStream input = httpConnection.getInputStream(); a:85L!~:l  
//logResponseHead(httpConnection); *HR+a#o  
9B /s  
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byte[] b = new byte[1024]; .%q$d d>>  
int nRead;
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 93j{.0]X  
{ ?w-1:NWjt  
nStartPos += fileAccessI.write(b,0,nRead); I%oRvg|q  
//if(nThreadID == 1) |,b2b2v?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zj<ahg%z  
} \V,c]I   
l^\(ss0~  
U4BqO :sd  
Utility.log("Thread " + nThreadID + " is over!"); bmu6@jT  
bDownOver = true; [F+(^- (  
//nPos = fileAccessI.write (b,0,nRead); Y9
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} cJCU*(7&  
catch(Exception e){e.printStackTrace ();} k<H%vg>{~s  
} ( #*"c  
} ~.J,A\F  
cFK @3a  
av-#)E  
//打印回应的头信息 bNGCOj  
public void logResponseHead(HttpURLConnection con) w5`#q&?  
{ CEuWw:)  
for(int i=1;;i++) (89Ji'dc
  
{ ',7a E@PJ  
String header=con.getHeaderFieldKey(i); F@Q^?WV  
if(header!=null) 7h%4]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *m9{V8Yi2  
Utility.log(header+" : "+con.getHeaderField(header)); LN4qYp6)G  
else 4S|=/f  
break; k;k}qq`d  
} e+.\pe\  
} l4rMk^>>  
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public void splitterStop() C-m*?))go  
{ `5q ;ssu  
bStop = true; yEq#Dr  
} *^]~RhjB  
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} d|XmasGN  
"xe=N  
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/* v!9i"@<!  
**FileAccess.java D8%AV;-Y  
*//文件访问(定位，写) @Y}uZ'jt'  
package NetFox; 7{e=="#*  
import java.io.*; qj!eLA-aD  
WNs}sNSf  
87V1#U^  
public class FileAccessI implements Serializable{ 7G<t"'  
&fwS{n;U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 er2cQS7R  
RandomAccessFile oSavedFile; x&Cp> +i  
long nPos; ; Y"N6%
 
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public FileAccessI() throws IOException Ql%qQ
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{ x({H{'9?  
this("",0); 9Ma0^_  
} rv>^TR*,!  
BQ/PGY>  
\L # INP4~  
public FileAccessI(String sName,long nPos) throws IOException S{#cD1>.  
{ maNW
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oSavedFile = new RandomAccessFile(sName,"rw"); %g3,qI  
this.nPos = nPos; DWU`\9xA*  
oSavedFile.seek(nPos); ffe1lw%  
} fY,|o3#  
>Kivuc  
=8Ehrlq
 
public synchronized int write(byte[] b,int nStart,int nLen) }tG3tz0%fX  
{ 2&Jdf  
int n = -1; }7s>B24J  
try{ HfB@vw^  
oSavedFile.write(b,nStart,nLen); HN6}R|IH  
n = nLen; El- ? %  
} e5?PkFV^a1  
catch(IOException e) a.@qGsIH  
{ :7g=b%;  
e.printStackTrace (); T6#CK  
} WC,+Cn e  
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X^@I].  
return n; rJJ[X4$  
} vUA0FoOp  
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} e`K)_>^n#  
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lFSe
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/* p|+B3  
**SiteInfoBean.java $t~@xCi]S  
*/ ememce,Np  
package NetFox; _oFs #kW  
2xwlKmI N  
e@#kRklV&  
public class SiteInfoBean { %JZZ%xc  
1ocJ+  
;CHi\+` 5  
private String sSiteURL; //Site's URL ~utJB 'gr  
private String sFilePath; //Saved File's Path ziE*'p  
private String sFileName; //Saved File's Name L';MP^  
private int nSplitter; //Count of Splited Downloading File CZ
<~3bEF  
&HW1mNF9  
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public SiteInfoBean() 3+Qxg+<  
{//nSplitter的缺省值为5 en F:>H4  
//default value of nSplitter is 5 (1R?s>3o  
this("","","",5); L!Cz'm"Nl  
} !v.9"!' N  
#R0A= !  
"=. t 36#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 20RXK1So  
{ 6K`c/)  
sSiteURL= sURL; `d]IX^;  
sFilePath = sPath; JAjmrX  
sFileName = sName; 'XrRhF (  
this.nSplitter = nSpiltter; 4+;$7"fJ  
:O<bA&:d  
x%+{VStA  
} d[ >`")2)  
g*UMG>  
;< jbLhHwD  
public String getSSiteURL() Yap?^&GV  
{ }@1q@xU  
return sSiteURL; I){\0vb@  
} A- YBQPE  
*^\HU=&  
X~=xXN.  
public void setSSiteURL(String value) ltB.Q  
{ uMb>xxf  
sSiteURL = value; WEg6Kz  
} m([(:.X/IX  
"\W-f  
=J-5.0Q\_\  
public String getSFilePath()
kum#^^4G|  
{ ^N}Wnk7ks'  
return sFilePath; D_mL,w  
} 7?8wyk|x  
"xmP6=1  
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public void setSFilePath(String value) fKC3-z
m  
{ acP+3u?r  
sFilePath = value; aprm0:Q^  
} Zn=T#o  
kE8>dmH23  
Wz4&7KYY  
public String getSFileName() zya5Jb:Sg  
{ \Ng\B.IQ  
return sFileName; 3f" %G\  
} v
K7\JZ>  
*-W#G}O0  
n+@F`]Ke  
public void setSFileName(String value) (&|_quP7O  
{ @E( 7V(m/  
sFileName = value; {t"+ 3zy'  
} Oa;X+  
EN{]Qb06A  
!Cgx.   
public int getNSplitter() " 96yp4v@  
{ %*aJLn+]_R  
return nSplitter; Jd\apBIf  
} 9)xUA;Qw?z  
)VL96did  
!Fo*e  
public void setNSplitter(int nCount) M.-"U+#aD  
{ Xs&TJ8a  
nSplitter = nCount; uw\2qU3g
k  
} WW+l'6.  
} k#8Ti"0  
{oc igR0  
iwz  
/* HEL!GC>#  
**Utility.java gBT2)2]  
*/ 7n]65].t  
package NetFox; Uv YF[@  
7Dnp'*H  
l`kWz5[~  
public class Utility { 5aad$f  
.=m,hu~  
x!\ONF5$  
public Utility() oH
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{ 43?^7_l-  
_&K  
|KB0P@
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} :m86 hBE.  
D=:04V}2+  
//线程睡眠 !D!~^\  
public static void sleep(int nSecond) UnVm1ZWZ  
{ @(P=Eh  
try{ !fBF|*/  
Thread.sleep(nSecond); t8^m`W  
} Y(cN}44  
catch(Exception e) +&zYZA8v  
{ 6v,z@!b  
e.printStackTrace ();  ^pn(=4  
} tiN?/  
} b:qY gg  
^[%%r3"$C  
//日志 V8eB$in  
public static void log(String sMsg) S'oGt&Z<  
{ Z/rP"|EuQ  
System.err.println(sMsg); 1B),A~Ip  
} tXJUvish  
BCe_@  
aP'"G^F  
public static void log(int sMsg) ARcv;H 5  
{ w9 w%&{j  
System.err.println(sMsg); u77E! z4Uz  
} vI$t+m:  
} %|G"-%_E  
Ax!+P\\2~  

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/* ~Lc066bLeq  
**TestMethod.java Y+K|1r
 
*/ Vh}SCUof'  
package NetFox; x0d~i!d  
9
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cRX~z  
public class TestMethod { lL]y~u  
4&/j|9=X  
]|<w\\^A  
public TestMethod() Xl@cHO=i  
{ ///xx/weblogic60b2_win.exe AoA!q>  
try{ WyP W*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); eY{+~|KZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q80S[au  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jA#/Z  
fileFetch.start(); (C]o,7cYS  
} UT}i0I9  
catch(Exception e){e.printStackTrace ();} wP"dZagpj  
EGl^!.'  
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} bQ|V!mrN}  
1s1=rZ!  
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public static void main(String[] args) <0S=,!  
{ S*AERm  
new TestMethod(); L
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} j5@:a  
} K'#E3={tt  
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