http断点续传简单实现（java)

/* M4D  @G  
**SiteFileFetch.java +u&[ j/  
*/ zk"8mTg  
package NetFox; iCLH  
import java.io.*; @]]&^ 7  
import java.net.*; 9g\;L:'  
~>N63I6  
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public class SiteFileFetch extends Thread { F{.\i*$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean G$2@N6  
long[] nStartPos; //开始位置 Oxa8ue?  
long[] nEndPos; //结束位置 .cHkh^EDY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 no W]E}nN  
long nFileLength; //文件长度 |}.}q  
boolean bFirst = true; //是否第一次取文件 zvVo-{6  
boolean bStop = false; //停止标志 bkc*it  
File tmpFile; //文件下载的临时信息 hNhEA $X5  
DataOutputStream output; //输出到文件的输出流 { 0-on"o  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） z:$ibk4#h  
public SiteFileFetch(SiteInfoBean bean) throws IOException hO&_VCk  
{ R7U%v"F>`  
siteInfoBean = bean; !/!ga)Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ];lZ:gT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jCXBp>9$M  
if(tmpFile.exists ()) &q@brX<,=  
{ .6T0d 4,1  
bFirst = false; Q4hY\\Hi  
read_nPos(); R :(-"GW'  
} 6M.|W;  
else \=7jp|{Yl  
{ Mm(#N/  
nStartPos = new long[bean.getNSplitter()]; %1:caa@_p  
nEndPos = new long[bean.getNSplitter()]; -- FzRO{D  
} JSi0-S[Y{  
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} 3z(4axH'  
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public void run() 92t.@!m`  
{ -fl6M-CYX  
//获得文件长度 ,oh;(|=  
//分割文件 ]d-.Mw,'  
//实例FileSplitterFetch vsZ?cd
 
//启动FileSplitterFetch线程 }{VOyPG  
//等待子线程返回 \Dy|}LE  
try{ A+gS'DZ9C  
if(bFirst) W>i"p~!  
{ /.<v,CR  
nFileLength = getFileSize(); Y#XRn_2D  
if(nFileLength == -1) QxdC[t$Lp  
{ B~N3k  
System.err.println("File Length is not known!"); KMz!4N  
} )S(Ly.  
else if(nFileLength == -2) XC)9aC@s  
{ *;]}`r  
System.err.println("File is not access!"); }ePl&-9T  
} *=2W:,$  
else ~bxev/$d  
{ <K`E*IaW  
for(int i=0;i<nStartPos.length;i++) j7gw?,  
{ xsn=Ji2 F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4$[o;t>  
} CDRbYO  
for(int i=0;i<nEndPos.length-1;i++) {\(MMTQ  
{ gWGDm~+  
nEndPos = nStartPos[i+1]; cO*g4VL"[  
} N UX |  
nEndPos[nEndPos.length-1] = nFileLength; QJRnpN/
 
} sHc-xnd  
} (X,i,qK/  
xBA"w:<  
#aU!f"SS  
//启动子线程 *>KBDFI  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5C9b*]-#  
for(int i=0;i<nStartPos.length;i++) e5>'H!)  
{ V7Cnu:0_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "H).2{3(x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), fDf[:A,8  
nStartPos,nEndPos,i); DJL
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $VvgzjrH  
fileSplitterFetch.start(); &]#L'D!"  
} $vfgYl4q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R-S<7Q3E0=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #%\0][Xf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {9U!0h-2"  
nEndPos = " + nFileLength); fk5'v
 
// fileSplitterFetch[nPos.length-1].start(); <[cpaZT,  
#mw!_]  
@m9pb+=v  
//等待子线程结束 q\?s<l63  
//int count = 0; > 0MP[  
//是否结束while循环 Z|uvrFa  
boolean breakWhile = false; 3TF_$bd{  
{uaDpRt  
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while(!bStop) 1xW!j!A;  
{ B/1j4/MS  
write_nPos(); Oh*~+/u}q  
Utility.sleep(500); r |C.K  
breakWhile = true; {fzX2qMZ]  
bGH#s {'5  
j)mU`b_  
for(int i=0;i<nStartPos.length;i++) A~bSB n: '  
{ _|#abLh%  
if(!fileSplitterFetch.bDownOver) B2ln8NF#Q  
{ )}`z<)3jP  
breakWhile = false; 6iyl8uL0J  
break; #dWz,e3   
} q`'f /CS  
} OuTV
74  
if(breakWhile) M?eP1v:<+G  
break; e$Ds2%SaT  
UhDQl%&He  
]- 1(r,  
//count++; Xb%q9Z  
//if(count>4) WMf / S"=  
// siteStop(); (@+pz/  
} t<p#u=jOa  
z3tx]Ade  
6(bN*.  
System.err.println("文件下载结束！"); z4:!*:.Asu  
} )t|:_Z  
catch(Exception e){e.printStackTrace ();} G&g;ROgY  
} \%a0Lp{ I  
[<RhaZz  
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//获得文件长度 [`\VgKeu  
public long getFileSize() AOR?2u  
{ i<^
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int nFileLength = -1; Y\]ZIvTSb  
try{ )}@D\(/@  
URL url = new URL(siteInfoBean.getSSiteURL()); ~v;I>ij  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nHdQe  
httpConnection.setRequestProperty("User-Agent","NetFox"); X
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int responseCode=httpConnection.getResponseCode(); Ek)drt7cy  
if(responseCode>=400) t{]Ew4Y4%O  
{ U6M~N0)Yr  
processErrorCode(responseCode); Ib#-M;{  
return -2; //-2 represent access is error U
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} 1!v{#w{u7  
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String sHeader; pWV_KS  
d?*]/ZiR  
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for(int i=1;;i++) }HoCfiE=X  
{ e'3V4iU]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ="voJgvw  
//Utility.log(in.readLine()); $gUlM+sK  
sHeader=httpConnection.getHeaderFieldKey(i); |H?t+Dyn)q  
if(sHeader!=null) _Vr- bpAf  
{ v76Gwu$d  
if(sHeader.equals("Content-Length")) W@T\i2r$z  
{ {cXr!N^K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &>JP.//spi  
break; |(>`qL{|  
} QoZV6  
} lmeTW0U@9(  
else tAAMSb9[d  
break; n~I-mR)"  
} BDI|z/~&  
} [H}> 2Q  
catch(IOException e){e.printStackTrace ();} {<,%_pJR  
catch(Exception e){e.printStackTrace ();} r].n=455[  
~7PD/dre  
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Utility.log(nFileLength); .4+Rac  
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return nFileLength; }=-0DSLVj  
} '=_(fa,  
yvYMk(LSF  
f% pT-#  
//保存下载信息（文件指针位置） *dw.=a9  
private void write_nPos() e|]e\Or>  
{ XGl2rX&  
try{ W+ S~__K  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +S4n416K  
output.writeInt(nStartPos.length); io4<HN  
for(int i=0;i<nStartPos.length;i++) Cyg2o<O@  
{ )E^S+ps  
// output.writeLong(nPos); [YOH'i&X  
output.writeLong(fileSplitterFetch.nStartPos); Z`S#> o  
output.writeLong(fileSplitterFetch.nEndPos); w2DC5ei'  
} b#_RZ  
output.close(); 2ioHhcYdJU  
} ~>CvZ7K  
catch(IOException e){e.printStackTrace ();} +RooU?Aq  
catch(Exception e){e.printStackTrace ();} 7:jLZ!mgi  
} 7f>=-sv  
B>53+GyMV  
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//读取保存的下载信息（文件指针位置） S1QMS  
private void read_nPos() uM2@&)u  
{ AF'<  
try{ %(YQ)=w  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `Lr], >aG  
int nCount = input.readInt(); /|?$C7%a\D  
nStartPos = new long[nCount]; up5f]:!  
nEndPos = new long[nCount]; A=<7*E  
for(int i=0;i<nStartPos.length;i++) 2HeX( rB  
{ &,&+p0CSI!  
nStartPos = input.readLong(); hXTfmFy{n  
nEndPos = input.readLong(); hF2e--  
} 42dv3bE"  
input.close(); 1/}H 0\9'  
} =-U0r$sK+F  
catch(IOException e){e.printStackTrace ();} sO.MUj;  
catch(Exception e){e.printStackTrace ();} gm9*z.S\'  
}  &K/?#  
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KQ\K:#  
private void processErrorCode(int nErrorCode) .#( vx;  
{ Q-<]'E#\(  
System.err.println("Error Code : " + nErrorCode); 6 5govor  
} %f]#P8VP  
y[_k/.1  
(]
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//停止文件下载 !xsfhLZK  
public void siteStop() *vb"mB  
{ ?bZH Aed  
bStop = true; ?NMk|+  
for(int i=0;i<nStartPos.length;i++) 0m_yW$w  
fileSplitterFetch.splitterStop(); )3h\QE!z  
sYKx3[V/  
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} a-NTA  
} }Ng P`m  
//负责部分文件的抓取 <M:BN6-yG  
**FileSplitterFetch.java 7e"}ojt$  
*/ 8['R D`O  
package NetFox; .+:iAnf  
Q#eMwM#~  
T[\1=h]  
import java.io.*; HI8mNX3 "j  
import java.net.*; '`jGr+K,wU  
:v^/k]S  
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public class FileSplitterFetch extends Thread { > 80{n8  
/!5Wd(:  
] ?DU8  
String sURL; //File URL m{q'RAw  
long nStartPos; //File Snippet Start Position (:l6R9'=  
long nEndPos; //File Snippet End Position 5JzvT JMx  
int nThreadID; //Thread's ID n>
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boolean bDownOver = false; //Downing is over S=qh7ML  
boolean bStop = false; //Stop identical KFrsXf  
FileAccessI fileAccessI = null; //File Access interface $)M3fZ$#  
)iN;1>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <i~xJi%1#  
{ \J^#2{d  
this.sURL = sURL; >=@-]X2%j  
this.nStartPos = nStart; 2`=jKt  
this.nEndPos = nEnd; YC6T0m  
nThreadID = id; 4(Lmjue]?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 si0}b~t  
} wps/{h,  
#UM,)bH  
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public void run() CNNqS^ct  
{ [> HKRVy  
while(nStartPos < nEndPos && !bStop) [mtp-4*  
{ ob7'''i  
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65LtCQ}  
try{ *;A ;)'  
URL url = new URL(sURL); a{8a[z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "| '~y}v_  
httpConnection.setRequestProperty("User-Agent","NetFox"); dseI~}  
String sProperty = "bytes="+nStartPos+"-"; ZLQmEF[>  
httpConnection.setRequestProperty("RANGE",sProperty); !#0)`4O  
Utility.log(sProperty); j<^!"_G]*?  
5%,3)H{;t  
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InputStream input = httpConnection.getInputStream(); _}R$h=YD  
//logResponseHead(httpConnection); Z '5itN^  
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byte[] b = new byte[1024]; 7@c!4hmr
U  
int nRead; Myc-lCE  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P+CV4;Xz  
{ rNN>tpZ}  
nStartPos += fileAccessI.write(b,0,nRead); 8Ths"zwn  
//if(nThreadID == 1) Y'/6T]a  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \[G'cE  
} ifn=De3+  
zhJeTctRz  
PD&e6;rj;  
Utility.log("Thread " + nThreadID + " is over!"); HoQb.Z  
bDownOver = true; YIe1AF}   
//nPos = fileAccessI.write (b,0,nRead); ZF7@b/-me  
} k3Yu"GY^  
catch(Exception e){e.printStackTrace ();} 8qe[x\,"8  
} ?m)<kY  
} <'\Nv._2a  
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//打印回应的头信息 F,_L}  
public void logResponseHead(HttpURLConnection con) er3Mvw  
{ 6))":<J  
for(int i=1;;i++) v`4w=!4  
{ 9^*RK6  
String header=con.getHeaderFieldKey(i); %H\b5& _y  
if(header!=null) dgVGP_~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); DAw1S$dM  
Utility.log(header+" : "+con.getHeaderField(header)); BK!Yl\I<  
else &4%pPL\f  
break; {a[BhK'g  
} TuwP'g[  
} 'n|U   
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public void splitterStop() ;@;aeu  
{ ^wy  
bStop = true; $#=d@Nw_  
} ?+}Su'pv}  
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} 9R=avfI  
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/* I"&cr>\  
**FileAccess.java {\>4)TA  
*//文件访问(定位，写) -VohU-6 |  
package NetFox; YdD; Qx#O  
import java.io.*;
Jt$YSp=!!  
&g?GF\Y  
uzp\V 39  
public class FileAccessI implements Serializable{ L@Rgiq|v-|  
+s#%\:Y M  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P(PBOB97  
RandomAccessFile oSavedFile; t|@5,J  
long nPos; {t;o^pUF  
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21!X[)r  
public FileAccessI() throws IOException ..yV=idI  
{ f`4=Bl&"{  
this("",0); jI,[(Z>  
} %;&lVIU0  
v7(7WfqP  
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public FileAccessI(String sName,long nPos) throws IOException  ]]p\1G  
{ *k(FbZ  
oSavedFile = new RandomAccessFile(sName,"rw"); 7nPg2K&  
this.nPos = nPos; bZ
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oSavedFile.seek(nPos); u-~ec{oBu  
} DVd8Ix<  
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~  
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public synchronized int write(byte[] b,int nStart,int nLen) >FE8CH!W&  
{ ")8l'^Mq2  
int n = -1; |-JG _i  
try{ eX\v;~W*  
oSavedFile.write(b,nStart,nLen); w,P@@Q E  
n = nLen; gb,ZN^3<-  
} ltOS()[X  
catch(IOException e) g:uVl;>  
{ J *LPv9)  
e.printStackTrace (); L\mF[Kd#+T  
} ?EUg B\  
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return n; !v2/sq$G  
} `GE8?UO-  
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} A^}#  
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/* /BgXY}JC.  
**SiteInfoBean.java 6EC',=)6R  
*/ n]6'!Eo  
package NetFox; OK4r)  
,LZA\XC  
v RD/67  
public class SiteInfoBean { 38sLyoG=i  
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private String sSiteURL; //Site's URL
#j7&2L  
private String sFilePath; //Saved File's Path Zf>:h   
private String sFileName; //Saved File's Name r!b>!  
private int nSplitter; //Count of Splited Downloading File 8}yrsF#  
'LoWp} f9  
dQ;8,JzIw&  
public SiteInfoBean() Dt!KgI3  
{//nSplitter的缺省值为5 $mK;{9Z  
//default value of nSplitter is 5 z1b@JCWE  
this("","","",5); ~g{1lcqQP  
} 8$c)]Bv  
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.+(ED  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) h,y_^cf  
{ =WUNBav  
sSiteURL= sURL; HG /fp<[   
sFilePath = sPath; -pJ\_u/&%`  
sFileName = sName; 6`-<N!  
this.nSplitter = nSpiltter; Yv=L'0K&  
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} OfrzmL<K  
v,opyTwG|  
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public String getSSiteURL() O!>#q4&]  
{ xVsI#`<a  
return sSiteURL; e 6wevK\  
} @ddCVxd  
@D[+@N  
&@xm< A\S  
public void setSSiteURL(String value) ?Xpk"N7  
{ j#3IF *"  
sSiteURL = value; q-^{2.ftcx  
} !]?kvf-3e  
!'!\>x$  
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public String getSFilePath() \DlMOG  
{ #-b}QhxH  
return sFilePath; [.Fm-$M-  
} s Y4wdG  
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tVf):}<h  
public void setSFilePath(String value) AaU!a  
{ |L89yjhWBs  
sFilePath = value; 7$Wbf4  
} .qf~t/o  

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\R-'<kN.*  
public String getSFileName() ttB>PTg#  
{ {~#PM>f  
return sFileName; pVzr]WFx  
} 9GT}_ ^fb  
!,Cbb }  
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public void setSFileName(String value) e]dFNunFq0  
{ kaoiSL<[6  
sFileName = value; B\aVE|~PB  
} oLq N  
1`s^r+11:  
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public int getNSplitter() rf`xY4I\  
{ 2qVoe}F  
return nSplitter; 2 p}I  
} Brd9"M|d  
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public void setNSplitter(int nCount) A@:U|)+4  
{ WWOt>C~
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nSplitter = nCount; cf^i!X0  
} YRv96|c,  
}  M_%c9g@x  
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/* 4#:Eq=(W  
**Utility.java }J-e:FUF#  
*/ (c"!&&S^ =  
package NetFox; VfDa>zV3  
@SaxM4  
oIj-Y`92!  
public class Utility { xpu2RE  
<Ter\o5%  
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public Utility() C(z'oi:f  
{ Ro `Xs.X  
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\  
} lOe|]pQ.,  
E`C
!q X>  
//线程睡眠 yOAC<<Tzus  
public static void sleep(int nSecond) KDV.ZSF7  
{ ufw[Ei$I:  
try{ Y%|dM/a`  
Thread.sleep(nSecond); T5I#7LN#  
} d%nX;w,   
catch(Exception e) 4vvQ7e7  
{ G+k wG)K  
e.printStackTrace (); .j>MsQP#\C  
} 23,pVo  
} 3u+i  
]|=`-)AP3  
//日志 c9c3o{(6Y  
public static void log(String sMsg) XJy.xI>;  
{ L 8;H_:~_'  
System.err.println(sMsg); a'n17d&  
} ~_F;>N~  
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public static void log(int sMsg) 02NVdpo[wU  
{ >ZeARCf"f  
System.err.println(sMsg); TXf60{:f  
} Z5*(xony0  
} N[fwd=$\
#  
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L<B)BEE.  
/* }QQ 7jE  
**TestMethod.java `R7dn/  
*/ X?&{< vz  
package NetFox; _6`GHx   
'=\>n(%Q  
utl-#Wwt/  
public class TestMethod { #sg dMrVQ  
"68X+!  
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public TestMethod() G)M! , Q  
{ ///xx/weblogic60b2_win.exe o`7 Z<HF  
try{ :xbj&
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5ug|crX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;volBfv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }; M@JMu,  
fileFetch.start(); .jC5 y&  
} kt\,$.
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catch(Exception e){e.printStackTrace ();} EA9.?F  
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} ".N{v1  
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public static void main(String[] args)  4~ L1~Gk  
{ . &`Y
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new TestMethod(); >}2 ,2  
} /lPnf7  
} fR+{gazk n  
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