http断点续传简单实现（java)

/* LUz`P6  
**SiteFileFetch.java 1hV&/Qr  
*/ I/v#!`L  
package NetFox; >SYOtzg%  
import java.io.*; 5"q{b1  
import java.net.*; >Yv#t.!  
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public class SiteFileFetch extends Thread { ^BI&-bR@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 09G]t1!,  
long[] nStartPos; //开始位置 K+yi_n L  
long[] nEndPos; //结束位置 f)Z'#[A*t7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 T).}~i;!  
long nFileLength; //文件长度 (.{."  
boolean bFirst = true; //是否第一次取文件 "[Tr"nI  
boolean bStop = false; //停止标志 =Q|s[F  
File tmpFile; //文件下载的临时信息 A?)(^  
DataOutputStream output; //输出到文件的输出流 Tm~jYgJ  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R9+f^o`W  
public SiteFileFetch(SiteInfoBean bean) throws IOException PM {L}tEQ  
{ *y>|  
siteInfoBean = bean; y92<(ziaX)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;hFB]/.v  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jar?"o  
if(tmpFile.exists ()) W`n_m&Y\  
{ [F
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bFirst = false; ZQ[s:  
read_nPos(); -OfAl~ 4  
} %u]>K(tU  
else SC2g5i`  
{ 0XL[4[LdA  
nStartPos = new long[bean.getNSplitter()]; uuCVI2|  
nEndPos = new long[bean.getNSplitter()]; v\kd78,  
} kaC
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} <R#:K7>O  
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public void run() bW'Y8ok[v  
{ 9x9E+DG#(  
//获得文件长度 `"bp-/  
//分割文件 %,)Xi  
//实例FileSplitterFetch Gv\fF;,R  
//启动FileSplitterFetch线程 jH4Wu`r;m  
//等待子线程返回 aII:Pzh]B  
try{ UAdj[m61  
if(bFirst) Q9t.*+  
{ j!`2Z@  
nFileLength = getFileSize(); KhbbGdmfS$  
if(nFileLength == -1) u\UI6/  
{ k${F7I(Tb  
System.err.println("File Length is not known!"); G@S'_  
} ^EKf_w-v  
else if(nFileLength == -2) g|4v>5Y  
{ :SpPT  
System.err.println("File is not access!"); B&H [z  
} Qp>Q-+e0  
else )i>T\B  
{ VnMiZAHR  
for(int i=0;i<nStartPos.length;i++) gH/k}M7tA#  
{ Ga^k1TQq  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gJBk&SDgtP  
} v#+tu,)V;  
for(int i=0;i<nEndPos.length-1;i++) .'N#qs_  
{ rkWW)h(e  
nEndPos = nStartPos[i+1]; oI%.oP}G  
} <i1P~  
nEndPos[nEndPos.length-1] = nFileLength; .DHRPel  
} S8Yh>j8-  
} @BXV>U2B{  
h%@#jvh?4  
[p_C?hHO  
//启动子线程  6@ )bZ|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6T~xjAuJ3T  
for(int i=0;i<nStartPos.length;i++) u8@>ThPD  
{  /=7[Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZCVN+::Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), cb~m==G  
nStartPos,nEndPos,i); 5bKn6O)K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mCx6$jz  
fileSplitterFetch.start(); -n~VMLd?@  
} U=bZy,FT$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b}r3x&)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [t`QV2um  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", I*K~GXWs#  
nEndPos = " + nFileLength); %@FTg$  
// fileSplitterFetch[nPos.length-1].start(); JEes'H}Y  
D}Lx9cL  
XX(;,[(_  
//等待子线程结束 0qV!-i  
//int count = 0; AHR%3W  
//是否结束while循环 Ie?C<(8Ul  
boolean breakWhile = false; izi=`;=D^  
W7"ks(  
Io&F0~Z;;(  
while(!bStop) X;0DQnAI8j  
{ NUH#  
write_nPos(); ~dK)U*Q  
Utility.sleep(500); K(HP PM\  
breakWhile = true; O(PG"c  
y85/qg)H^  
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for(int i=0;i<nStartPos.length;i++) y8un&LP  
{ Ij}RlYQz  
if(!fileSplitterFetch.bDownOver) nV%1/e"5  
{ BUcze\+  
breakWhile = false; ~V"D|U;i +  
break; {@oYMO~  
} |L4K#  
} rr#&0`]  
if(breakWhile) }4kd=]Nk  
break; \5Jpr'mY5  
|,Y(YSg.  
}cG
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//count++; g Xvuv^  
//if(count>4) t3b
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// siteStop(); oToUpkAI  
} g#1_`gK  
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System.err.println("文件下载结束！"); YzSUJ=0/  
} { CkxUec  
catch(Exception e){e.printStackTrace ();} 0zaE?dA]  
} @U(D&_H,K  
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w Maib3Q  
//获得文件长度 &V[m{.  
public long getFileSize() RUmJ=i'4/  
{ WLEjRx  
int nFileLength = -1; s3W)hU)  
try{ Mjrl KI}f/  
URL url = new URL(siteInfoBean.getSSiteURL()); 9Bl_t}0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rm NqS+t  
httpConnection.setRequestProperty("User-Agent","NetFox"); &CFHH"OsT  
<DCrYt!1}c  
t7("geN]  
int responseCode=httpConnection.getResponseCode(); /z*?:*  
if(responseCode>=400) BM#cosV7%h  
{ b:Dr_|  
processErrorCode(responseCode); XS]=sfN  
return -2; //-2 represent access is error Q uy5H  
} rE-Xv. |
 
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6)kF!/J  
String sHeader; EaG3:<>J  
4,T!zT6&  
q3B#rje>h  
for(int i=1;;i++) _* ]~MQ=  
{ ._"U{ f2V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +s c|PB  
//Utility.log(in.readLine()); q-3%.<LL  
sHeader=httpConnection.getHeaderFieldKey(i); -4o6OkK<  
if(sHeader!=null) !dYkvoQNn  
{ BDyOX6  
if(sHeader.equals("Content-Length")) Sve~-aG  
{ Z+@"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]QM6d(zDA  
break; `9Zoq=/  
} n|Vs27  
} *[(O&L&0  
else PmO ut
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break; 1g5%Gr/0$5  
} ScYw3i  
} 9~bje^M  
catch(IOException e){e.printStackTrace ();} &!vJ3:  
catch(Exception e){e.printStackTrace ();} ~sshhuF  
}kdYR#{s  
0:R}  
Utility.log(nFileLength); =xWZJ:UnU  
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return nFileLength; }9 N, +*  
} 11}X2j~Ww  
[ /w{,+U  
}x`W+r  
//保存下载信息（文件指针位置） 2Otd  
private void write_nPos() i)g=Lew  
{ 8i=J(5=  
try{ \B8tGog  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %*lOzC  
output.writeInt(nStartPos.length); T>e!DOW;  
for(int i=0;i<nStartPos.length;i++) gEbe6!; q3  
{ '+N!3r{G  
// output.writeLong(nPos); 6uW?xB9  
output.writeLong(fileSplitterFetch.nStartPos); \dTX%<5D  
output.writeLong(fileSplitterFetch.nEndPos); 
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} +',[q  
output.close(); CTQF+Oe8O  
}
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catch(IOException e){e.printStackTrace ();} $As;Tvw.  
catch(Exception e){e.printStackTrace ();} P7O$*  
} Nl,M9  
^EWkJW,Yc  
T_|%nF-+  
//读取保存的下载信息（文件指针位置） >Lx,<sE  
private void read_nPos() 2W:R{dHE  
{ J^8(h R  
try{ z %{Z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); '=K [3%U  
int nCount = input.readInt(); {m~.'DU  
nStartPos = new long[nCount]; O*xC}$OOn  
nEndPos = new long[nCount]; 16ahU$@-  
for(int i=0;i<nStartPos.length;i++) h3D~?Iom  
{ mI
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nStartPos = input.readLong(); GOuBNaU{  
nEndPos = input.readLong(); 6&_"dg"  
} 9W88_rE'e}  
input.close(); 4$.$j=Ct."  
} 'NHtCs=F   
catch(IOException e){e.printStackTrace ();} g"aWt% P  
catch(Exception e){e.printStackTrace ();} nf=*KS\v  
} 6t/nM  
.'N:]G@!  
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private void processErrorCode(int nErrorCode) S`g:zb_  
{ !=%0  
System.err.println("Error Code : " + nErrorCode); )@+lfIE(l  
} )a"rj5~-  
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D#Qfa
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//停止文件下载 vU,AOK[l{  
public void siteStop() :j_OO5b!  
{ !lQGoXQ'4  
bStop = true; W <.h@Rz+  
for(int i=0;i<nStartPos.length;i++) i4;`dCT|A  
fileSplitterFetch.splitterStop(); gwVfiXR4  
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} /){F0Zjjt  
} +/ s2;G  
//负责部分文件的抓取 EC9D.afy&  
**FileSplitterFetch.java s}"5uDfn1F  
*/ s&(,_34  
package NetFox; d'j8P  
,K4*0!TXP  
!;Hi9,<#7g  
import java.io.*; x~1.;dBF  
import java.net.*; r*$$82s  
HqM>K*XKU  
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public class FileSplitterFetch extends Thread { _<Hx1l~  
F:$Dz?F0v  
(EZ34,k'S  
String sURL; //File URL j5hM|\]  
long nStartPos; //File Snippet Start Position 5vxKkk&i4l  
long nEndPos; //File Snippet End Position iMgfF_r  
int nThreadID; //Thread's ID OPm
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boolean bDownOver = false; //Downing is over 6AS'MD%&  
boolean bStop = false; //Stop identical >R|*FYam  
FileAccessI fileAccessI = null; //File Access interface ?Q$LIoR  
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>y P`8Oq[  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #$\cRLPg  
{ kk`BwRh)d;  
this.sURL = sURL; #Bo/1G=  
this.nStartPos = nStart; L|sWSrqd  
this.nEndPos = nEnd; - 0t  
nThreadID = id; 5Gj?'Wov9  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,p(4OZz5,  
} WW.\5kBl8  
!83x,*O  
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public void run() &p?Oo^  
{ W@S'mxk#*  
while(nStartPos < nEndPos && !bStop) qF9rY)ifm  
{ @G/':N   
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&&1q@m,cP  
try{ 6{O#!o*g  
URL url = new URL(sURL); >.R6\>N%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Bx(+uNQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); Kd_WN;l  
String sProperty = "bytes="+nStartPos+"-"; o]NL_SM_  
httpConnection.setRequestProperty("RANGE",sProperty); V/j]UK0$  
Utility.log(sProperty); -25#Vh  
+uPN+CgQ@  
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InputStream input = httpConnection.getInputStream(); h6*=Fn7C  
//logResponseHead(httpConnection); -t9oL3J  
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byte[] b = new byte[1024]; qa![oMKc  
int nRead; =goZI67  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) MDkIaz\U  
{ :oB4\/(G#  
nStartPos += fileAccessI.write(b,0,nRead); .?SClTqg  
//if(nThreadID == 1) ;WIL?[;w  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c ;3bX6RD*  
} O$ i6r]j_  
>J=x";,D|~  
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Utility.log("Thread " + nThreadID + " is over!"); da@y*TO#i  
bDownOver = true; /,v:!*  
//nPos = fileAccessI.write (b,0,nRead); Q6S[sTKR  
} ^_<>o[qE  
catch(Exception e){e.printStackTrace ();} Q:+Y-&||"  
} ^v3+w"2  
} [BhpfZNKRA  
}\u~He%  
+N[dYm  
//打印回应的头信息 [Hdk=p  
public void logResponseHead(HttpURLConnection con) @{_PO{=\C  
{ '4sT+q  
for(int i=1;;i++) m@JU).NKCS  
{ |xzqYu?o  
String header=con.getHeaderFieldKey(i); 2h&pm  
if(header!=null) 5q]
u:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OxF\Hm)(  
Utility.log(header+" : "+con.getHeaderField(header)); }jd[>zk  
else We#*.nr{3Z  
break; whKr3)  
} z>j%-3_1  
} se_zCS4Y  
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public void splitterStop() !W$3p'8Tu  
{ uMsKF%m  
bStop = true; E08AZOY&g  
} +:&(Ag  
3|:uIoR{  
5, Yk5?l<'  
} cb%w,yXw  
{>FA ~}cX.  
4BEVG&Ks  
/* Wr)%C  
**FileAccess.java ZJ=C[s!wu  
*//文件访问(定位，写) V2/+SvB2  
package NetFox; rvE!Q=y~  
import java.io.*; `ss]\46>  
Tjs-+$P+  
!W$Br\<  
public class FileAccessI implements Serializable{ nBiSc*  
q/OraPAB  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 UjKHGsDi4  
RandomAccessFile oSavedFile; $E7yJ|p{
 
long nPos; )%j)*Ymz;  
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/@#)j( eY/  
public FileAccessI() throws IOException ; wHuL\  
{ zx'`'t4~  
this("",0); 3al5Vu2:  
} b1*6)  
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M3z7P.\G  
public FileAccessI(String sName,long nPos) throws IOException 0>e>G(4(8  
{ *Mp<4B  
oSavedFile = new RandomAccessFile(sName,"rw"); 9q8 rf\&  
this.nPos = nPos; Ej34^*m9k  
oSavedFile.seek(nPos); S'@"a%EV  
} -x_iqrB  
h,p&/oU4U  
b&_p"8)_  
public synchronized int write(byte[] b,int nStart,int nLen) #&8Opo(  
{ i'5bPW  
int n = -1; Ow^%n(Ezh  
try{ &0C!P=-p  
oSavedFile.write(b,nStart,nLen); 73<iK]*c  
n = nLen; \U-5&,fP  
} sN?:9J8  
catch(IOException e) eqf~5/Z  
{ ud#8`/!mq  
e.printStackTrace (); <%Rr-,  
} (CV=0{]  
v*^2[pf  
9(PFd%  
return n; ~w*ojI  
} CKR9APkv  
dk]ro~ [  

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} ^}[ N4  
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/* )/pPY  
**SiteInfoBean.java ^R$dG[Qf  
*/ ZT8j9zs  
package NetFox; zF$wz1 %  
N|)V/no6  
OlJj|?z$  
public class SiteInfoBean { Dm^kuTIG  
P3|<K-dFAK  
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private String sSiteURL; //Site's URL O^$Zz<  
private String sFilePath; //Saved File's Path dEp=;b s  
private String sFileName; //Saved File's Name od fu7P_  
private int nSplitter; //Count of Splited Downloading File PWU#`>4  
N{yZk"fq:6  
6};oLnO  
public SiteInfoBean() 7(;VUR%%.  
{//nSplitter的缺省值为5 X[ (J!"+  
//default value of nSplitter is 5 D-!%L<<  
this("","","",5); T{M:)}V  
} fpi6pcof  
Jp#cFUa t  
cOgtBEhn  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !;a<E:  
{ 5S?yj  
sSiteURL= sURL; mTg
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sFilePath = sPath; 1hWz%c|  
sFileName = sName; .gJKr  
this.nSplitter = nSpiltter; xL"%2nf  
2Qj)@&zKe#  
}+J@;:  
} -tdG}Gu  
QAwj]
_  
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public String getSSiteURL() y|se^dn  
{ }"Cn kg  
return sSiteURL; NZ5~\k  
} -EaZ<d[|0  
(c2\:hvy  
eV0S:mit  
public void setSSiteURL(String value) U;@jl?jnG  
{ bg}77Y'^  
sSiteURL = value; 8|GpfW3p2  
} PgAfR:Y!  
aO%FQ)BT  
E}=NZqOB!  
public String getSFilePath() mNel3J3  
{ $O8V!R*  
return sFilePath; ={'($t%|T  
} BkfBFUDQ  
qS|VUy4  
9A(K_d-!H  
public void setSFilePath(String value) auW]rwY  
{ !ei20@  
sFilePath = value; OvG0UXRU  
} ""^BW Re D  
{B.]w9  
2*YXm>|1  
public String getSFileName() :<8V2  
{ -RQQ|:O$  
return sFileName; yZ$;O0f&&  
} @F^L4 N':  
gDNW~?/  
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public void setSFileName(String value) @|Bp'`j%J  
{ zEfD{I  
sFileName = value; U&$]?3?  
} =Gz>ZWF  
"Cj
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KB*=a  
public int getNSplitter() {OrE1WHB  
{ $yFuaqG`Wo  
return nSplitter; F$p*G][  
} N|
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RpP[ymMZJ  
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public void setNSplitter(int nCount) 7h/Q;P5  
{ wg_CI,Kq  
nSplitter = nCount; 72vGfT2HtZ  
} _hL4@C  
} TbAdTmW  
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*"{Z?< 3  
/* @b\_696.  
**Utility.java .hNw1~Fj  
*/ S{7ik,Gdg  
package NetFox; P\6T4s  
={@ @`yP^$  
Ny7=-]N4{"  
public class Utility { ~LW%lMy;^|  
^-*Tn  
Mqf}Aiqk;  
public Utility() OrJlHMz  
{ 8yz((?LrDh  
)
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} Bp{`%86SE  
ma
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//线程睡眠 MGKeD+=5  
public static void sleep(int nSecond) %<#3_}"T|  
{ SJc@iffS  
try{ lrX0c$)  
Thread.sleep(nSecond); @&xaaqQ-  
} v[DbhIXU  
catch(Exception e) -Dq:Y,%q  
{ }%FuL5Tx  
e.printStackTrace (); SLjf<.S  
} .C;_4jE  
} (yAvDyJOn  
?&<o_/`-H5  
//日志 5~%,u2  
public static void log(String sMsg) Y{2d4VoW6  
{ -YjgS/g  
System.err.println(sMsg); j484b2uj1  
} ;zE5(3x  
D<3V#Opw  
z>p`!-'ID  
public static void log(int sMsg) QT= ,En  
{ ,ibPSN5Ca  
System.err.println(sMsg); !+DJhw&c,  
} 1mVVPt^6  
} 5-WRv;  
?7nr\g"g(  
=_m9so  
/* 8u'O`j  
**TestMethod.java $FusDdCv3  
*/ @-&(TRbZo  
package NetFox; o|;eMO-  
Am4^v?q  
;y~{+{{Ow  
public class TestMethod { 1S(\2{Ylo  
H9san5{  
>g>`!Sf  
public TestMethod() MYw8wwX0kJ  
{ ///xx/weblogic60b2_win.exe d=Df.H+3  
try{ 24jtJC,7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,s><kHJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9sU+
IT K4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Gkv~e?Kc~^  
fileFetch.start(); f7Df %&d  
} 7*>S;$
 
catch(Exception e){e.printStackTrace ();} lTr*'fX  
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} 6vgBqn[  
`/w\2n  
 &(1H!  
public static void main(String[] args) K/2.1o;9  
{ 3xzkZ8]/  
new TestMethod(); S~k*r{?H})  
} Cx+WLD  
} -.{oqs
$  
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