http断点续传简单实现（java)

/* ' P"g\;Ij  
**SiteFileFetch.java \+PIe7f_  
*/ h5zVGr  
package NetFox; %"$@%"8;3  
import java.io.*; `TKD<&oL  
import java.net.*; b'@we0V@S  
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public class SiteFileFetch extends Thread { 9ptFG]lZ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean T3&`<%,f  
long[] nStartPos; //开始位置 F phDF  
long[] nEndPos; //结束位置 !>^JSHR4t  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B0UJq./`  
long nFileLength; //文件长度 ub?K,  
boolean bFirst = true; //是否第一次取文件 Pt< s* (  
boolean bStop = false; //停止标志 72db[  
File tmpFile; //文件下载的临时信息 -`c:}m  
DataOutputStream output; //输出到文件的输出流 'W. Vr
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} /^C|iS7  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） vq'c@yw;  
public SiteFileFetch(SiteInfoBean bean) throws IOException `(4pu6uT  
{ QP I+y8N=  
siteInfoBean = bean; w=b(X q+:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }odV_WT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); TW&DFKK`  
if(tmpFile.exists ()) *gsAn<  
{ ZFh+x@  
bFirst = false; I0= NaZ7  
read_nPos(); r8MZvm2  
} q`|CrOzO  
else wVK*P -C  
{ vFmJ;J  
nStartPos = new long[bean.getNSplitter()]; Zy"=y+e!E;  
nEndPos = new long[bean.getNSplitter()]; {OMgd3%14  
} $\
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} }
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public void run() v@ C,RP9  
{ FpV`#6i7  
//获得文件长度 2h~-  
//分割文件 3C>qh{z"  
//实例FileSplitterFetch Y#V8(DTyH  
//启动FileSplitterFetch线程 EYS>0Y  
//等待子线程返回 Do-^S:.  
try{ t@zdm
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if(bFirst) VAQ)Hc]  
{ | FM }  
nFileLength = getFileSize(); Q%=YM4;  
if(nFileLength == -1) KpZ:Nh$  
{ <EX7WA  
System.err.println("File Length is not known!"); cz
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} Ibr%d2yS=  
else if(nFileLength == -2) ReB7vpd  
{ RNJFSD.  
System.err.println("File is not access!"); GUp;AoQ  
} PBqy F  
else :>3=gex@^0  
{ Ws[D{dS/  
for(int i=0;i<nStartPos.length;i++) U..<iNQE5  
{ 8^ep/b&|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .QWhK|(.!  
} `$;+g ,  
for(int i=0;i<nEndPos.length-1;i++) x!7yU_ls`  
{ m9$:9yRm  
nEndPos = nStartPos[i+1]; 3fS}:!sQ
 
} 9t:]  
nEndPos[nEndPos.length-1] = nFileLength; t1]6(@mj5  
} Csst[3V  
} 
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'?Bg;Z'L%  
M].8HwC+  
//启动子线程 w<wV]F*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,{}#8r`+*  
for(int i=0;i<nStartPos.length;i++) kE
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{ Mhpdaos  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -E>)j\{PX7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), t%0?N<9YkU  
nStartPos,nEndPos,i); .J.vC1 4gi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 85Y|CN] vQ  
fileSplitterFetch.start(); kToOIx  
} >%%=0!,yX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), laREjN/\`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I}
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", mf$j03tu  
nEndPos = " + nFileLength); 4YA./j%'  
// fileSplitterFetch[nPos.length-1].start(); L4'[XcY  
j~av\SCU*  
RVM&4#E  
//等待子线程结束 khX|"d360  
//int count = 0; Fz"ff4Bx [  
//是否结束while循环 ^$?qT60%d|  
boolean breakWhile = false; C3;[e0.1b  
{[#(w75R{  
c.K =(y*  
while(!bStop) "~+.Af  
{ %vqT#+x  
write_nPos(); hl/itSl$  
Utility.sleep(500); __N.#c/l{  
breakWhile = true; SG]
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for(int i=0;i<nStartPos.length;i++) nB@UKX  
{ pdz'!I  
if(!fileSplitterFetch.bDownOver) ,@CfVQz  
{ Yv\!vW7I  
breakWhile = false; Gp2!xKgm  
break; x7ATI[b[  
}  W'/>et  
} <0j{ $.  
if(breakWhile) <|F-Dd  
break; ;iX<`re~  
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-F`he=Ev9  
//count++; *@M3p}',M  
//if(count>4) X0i3_RVa  
// siteStop(); @EZ>f5IO+  
} /tKGwX]y  
~<O,Vs_C/  
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System.err.println("文件下载结束！"); zy)i1d  
} {BOLPE-  
catch(Exception e){e.printStackTrace ();} PdE>@0X?M  
} rK=6]j(K  
I,P!@  
>4)g4~'n!  
//获得文件长度 %$n02"@  
public long getFileSize() L3c*LL  
{ Q1V2pP+=@  
int nFileLength = -1; x:-`o_Q*i  
try{ w-rOecwFvu  
URL url = new URL(siteInfoBean.getSSiteURL()); mK\aI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e-6(F4  
httpConnection.setRequestProperty("User-Agent","NetFox"); @PXXt#  
Z3;=w%W  
[j0w\{  
int responseCode=httpConnection.getResponseCode(); <94WZ?{p  
if(responseCode>=400) u4"r>e6_B  
{ ~ x`7)3  
processErrorCode(responseCode); -Bv12ymLG  
return -2; //-2 represent access is error oyvtZ/@  
} h$&rE@N|  
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String sHeader; pt})JMm  
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for(int i=1;;i++) n~%}Z[5D  
{ :~-i&K
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {3 o%d:  
//Utility.log(in.readLine()); z93nYY$`Y  
sHeader=httpConnection.getHeaderFieldKey(i); _LLshV3  
if(sHeader!=null) yWuIu>VJ  
{ "::9aYd!  
if(sHeader.equals("Content-Length")) _3&/(B%H  
{ ZR mPP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); gz\j('~-D  
break; IUawdB5CB  
} R0IF'  
} y
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else |_I[1%&`N  
break; s01$fFJgO  
} pn*d[M|k  
} I~k=3,7<  
catch(IOException e){e.printStackTrace ();} swt\Ru6,  
catch(Exception e){e.printStackTrace ();} .+uVgSN  
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Utility.log(nFileLength); JD-Becz  
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return nFileLength; )|:8zDuJ  
} 5~yQ>h  
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*vD/(&pQ1:  
//保存下载信息（文件指针位置） pLo;#e8'f  
private void write_nPos() ChVY Vx(  
{ Xky@[Td*  
try{ &m4f1ZO*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ku-cn2M/  
output.writeInt(nStartPos.length); D:6N9POB  
for(int i=0;i<nStartPos.length;i++) C#T)@UxBZ  
{ `|JI\&z  
// output.writeLong(nPos); 'Ye]eL,I\  
output.writeLong(fileSplitterFetch.nStartPos); <L%HG  
output.writeLong(fileSplitterFetch.nEndPos); !,R  
} /O_0=MLp  
output.close(); %cd]xQpCp  
} d(\1 }l  
catch(IOException e){e.printStackTrace ();} IY~ {)X  
catch(Exception e){e.printStackTrace ();} `43vxcMg  
} 63SVIc~wT  
n }TTq6B  
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//读取保存的下载信息（文件指针位置） wNbTM.@  
private void read_nPos() i(z+a6^@|  
{ 35}P0+  
try{ nHE+p\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9M;I$_U`vj  
int nCount = input.readInt(); <G&WYk%u*  
nStartPos = new long[nCount]; Zr5'TZ`$  
nEndPos = new long[nCount]; Lq%[A*`^  
for(int i=0;i<nStartPos.length;i++) .^BWR  
{ VDPxue  
nStartPos = input.readLong(); d{?)q
 
nEndPos = input.readLong(); U:J /\-  
} -5o?#%  
input.close(); #qPVQt  
} q~mcjbLz  
catch(IOException e){e.printStackTrace ();} e1oFnu2R  
catch(Exception e){e.printStackTrace ();} ADTU{6UPS  
} gp%tMTI1  
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private void processErrorCode(int nErrorCode) IM$'J  
{ <.: 5Vx(Aw  
System.err.println("Error Code : " + nErrorCode); l DgzM3  
} W&Y4Dq^  
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>Zi|$@7t-  
//停止文件下载 }'%$7vL`Ft  
public void siteStop() Qh/lT$g  
{ DrW/KU,{+(  
bStop = true; ><MGZ?-N  
for(int i=0;i<nStartPos.length;i++) \%Pma8&d  
fileSplitterFetch.splitterStop(); >3v0yh_3  
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} ,^Ex}Z  
} gGF$M `  
//负责部分文件的抓取 *4zoAslU1  
**FileSplitterFetch.java (L]T*03#  
*/ 4mki&\lw`  
package NetFox; )tJL@Qo  
fN~8L}!l  
^w.k^U=B  
import java.io.*; S^*(ALFPj  
import java.net.*; &pa)Ee>  
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public class FileSplitterFetch extends Thread { e,PQ)1  
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String sURL; //File URL 5;r({J  
long nStartPos; //File Snippet Start Position \UVT_=Y  
long nEndPos; //File Snippet End Position O%rS;o  
int nThreadID; //Thread's ID E;ndw/GZjR  
boolean bDownOver = false; //Downing is over ?14X8Mb8W_  
boolean bStop = false; //Stop identical \Qe'?LRu{  
FileAccessI fileAccessI = null; //File Access interface qdg= Imx  
&QiAM`MbC=  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p?EEox  
{ yTMGIS
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this.sURL = sURL; Ktj(&/~}  
this.nStartPos = nStart; %a%+!wX0x  
this.nEndPos = nEnd; #l8K8GLuf  
nThreadID = id; 0nF>zOmc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LGdf_M-f  
} \J#I}-a&j  
#)IdJ]  
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public void run() 2b vYF;<r  
{ 6"#Tvj~-8  
while(nStartPos < nEndPos && !bStop) 5k!(#@a_T  
{ ]kU~#WT  
@5uyUSt]  
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try{ M$E8:  
URL url = new URL(sURL); TU^tW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [xH2n\7  
httpConnection.setRequestProperty("User-Agent","NetFox"); EV;;N  
String sProperty = "bytes="+nStartPos+"-"; [m@e^6F0U  
httpConnection.setRequestProperty("RANGE",sProperty); Fp* &os  
Utility.log(sProperty); {ILQ CvP*  
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InputStream input = httpConnection.getInputStream(); pD)/-Dgdm  
//logResponseHead(httpConnection); I=Lj_UF4  
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byte[] b = new byte[1024]; }T&;*ww  
int nRead; J^e|"0d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) c'VtRE# z~  
{ t2U]CI%  
nStartPos += fileAccessI.write(b,0,nRead); &vGEz*F  
//if(nThreadID == 1) pNk,jeo
  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e=NQY8?  
} Z2Y583D  
}tg:DG  
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Utility.log("Thread " + nThreadID + " is over!"); n$Oky-P"  
bDownOver = true; Qc)RrqYNGF  
//nPos = fileAccessI.write (b,0,nRead); 4Q>jP3  
} tue%L]hc  
catch(Exception e){e.printStackTrace ();}  s`{#[&[  
} L<nkI  
} pR^Y|NG!  
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//打印回应的头信息 ztt%l #  
public void logResponseHead(HttpURLConnection con) =.3P)gY)  
{ I'wk/  
for(int i=1;;i++) `qy6qKl N  
{ ^?l-YnQqm?  
String header=con.getHeaderFieldKey(i); L M<=j  
if(header!=null) JCMEhI6d*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); u{dN>}{  
Utility.log(header+" : "+con.getHeaderField(header)); MsVI <+JZ  
else Eo3Aak o  
break; I@3c QxI  
} Z[A|SyZp  
} ^_"q`71Dk  
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public void splitterStop() Bo\dt@0;  
{ 5In8VE !P  
bStop = true; dJ"xW;"  
} %emPSBf@  
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} jgfP|oD  
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/* ~k<31 ez  
**FileAccess.java W1,L>Az^Ts  
*//文件访问(定位，写) g5YsVp  
package NetFox; ?9ho|  
import java.io.*; :{='TMJ7  
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public class FileAccessI implements Serializable{ .mU.eL
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 .KMi)1L)  
RandomAccessFile oSavedFile; GZ>% &^E  
long nPos; jtOsb91c}  
8@*|T?r  
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public FileAccessI() throws IOException Y8xnvK*  
{ B*?PB]  
this("",0); (dprY1noC  
} [";5s&)q  
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public FileAccessI(String sName,long nPos) throws IOException FwzA_ nn  
{ x;]{ 8#-z  
oSavedFile = new RandomAccessFile(sName,"rw"); $%"}N_M  
this.nPos = nPos; Y>m=cqR  
oSavedFile.seek(nPos); [<I `slK  
} 2%yJo7f$[  
J7] 60H#P  
<R8Z[H:bV  
public synchronized int write(byte[] b,int nStart,int nLen) ; SM^  
{ hd BC ^n  
int n = -1; M HB]'  
try{ &>b1ES.>  
oSavedFile.write(b,nStart,nLen); /6*.%M>r  
n = nLen;
._nKM5.  
} 491I  
catch(IOException e) j7 3@Yi%  
{ oVsazYJ|?  
e.printStackTrace (); =8D4:Ds  
} ?YykCJJ ~@  
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return n; *g6o ;c  
} Czxrn2p/  
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}
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ay|{!MkQ  
/* }]?G"f t K  
**SiteInfoBean.java \
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*/ Y/(-mcR  
package NetFox; X($SBUS6  
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public class SiteInfoBean { cN>i3}fq  
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3:#rFb  
private String sSiteURL; //Site's URL 9Dw&b  
private String sFilePath; //Saved File's Path .p}Kl$K]
 
private String sFileName; //Saved File's Name hyoZh Y  
private int nSplitter; //Count of Splited Downloading File ;qK6."b`;  
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public SiteInfoBean() .U%"oD  
{//nSplitter的缺省值为5 elB 8   
//default value of nSplitter is 5 mK4|=Q  
this("","","",5); -=IM8Dny  
} `%p6i| _Q  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $'*BS  
{ MT0{hsuK9  
sSiteURL= sURL; elgQcJ99  
sFilePath = sPath; &Z!2xfQy>  
sFileName = sName; -`EoTXT*U  
this.nSplitter = nSpiltter; V/e_:xECC  
0&@pX~h:  
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} 8l0 (6x$  
n#cN[C9  
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public String getSSiteURL() W F<V2o{k  
{ Y_sVe  
return sSiteURL; ![^h<Om  
} -+_&#twU  
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public void setSSiteURL(String value) FG:BRS<m~  
{ B,,d~\  
sSiteURL = value; p04+"  
} n`xh/vGm#  
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public String getSFilePath() O%e.u>=4%  
{ Sw'?$j^3  
return sFilePath; f*Js= hvO  
} ,O$C9pH9  
Iq\oB  
Lm#d.AD)  
public void setSFilePath(String value) 926oM77  
{ ?UDO%`X  
sFilePath = value; i]pG}SJ  
} faX#KRpfd  
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public String getSFileName() BxYA[#fd}  
{ D7/Bp4I#o  
return sFileName; ifZNl,  
}
?Nql7F4  
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public void setSFileName(String value) 8-YrmP2k  
{ uF"`y&go  
sFileName = value; *wcoDQ b;  
} kZ%W?#  
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public int getNSplitter() f om"8iL1  
{ x~tQYK   
return nSplitter; ;NeEgqW"
 
} i]%"s_l  
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public void setNSplitter(int nCount) BK SK@OV  
{ QC,(rB  
nSplitter = nCount; ,8nZzVo  
} gi@ji-10  
} B?Sfcq-  
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/* ld:alEo  
**Utility.java 6
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*/ ~(^*?(Z  
package NetFox; G$uOk?R#5c  
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public class Utility { wNhR(M7  
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public Utility() Ab<Ok\e5  
{ <>Ddxmw  
h!
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} #(g+jb0E  
bMOM`At>z  
//线程睡眠 pt
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public static void sleep(int nSecond) qpqz. {\  
{ 'oQP:*Btl3  
try{ kS#DKo  
Thread.sleep(nSecond); | 8Egw-f  
} H-KwkH`L4  
catch(Exception e) *oX]=u&  
{ VD3MJ8!w  
e.printStackTrace (); 5=h'!|iY  
} fB,1s}3Hn  
} C!k9JAa$Z  
i)PV{3v$J  
//日志 +xBK^5/x  
public static void log(String sMsg) b_gN?F7_  
{ TKu68/\)  
System.err.println(sMsg);  `pd   
} 7e{X$'  
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public static void log(int sMsg) Dq%r !)  
{ skDk/-*R  
System.err.println(sMsg); 6Vbv$ AU  
} UtBlP+bE?y  
} V*7Z,nA  
5ZyBP~  
%*
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/* ~{,vg4L  
**TestMethod.java y(3c{y@~X  
*/ "i{_<;p O  
package NetFox; q?-3^z%u  
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public class TestMethod { qz=#;&ZU  
jFNs=D&(  
S|q!? /jqj  
public TestMethod() *iRm`)zC(  
{ ///xx/weblogic60b2_win.exe P 5qa:<  
try{ O? Gl4_y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (4/]dTb  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,8=`*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "?eH=!  
fileFetch.start(); _L4<^Etfm  
} g#'fd/?Q  
catch(Exception e){e.printStackTrace ();} &J^4Y!gt  
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} S\3AW,c]w  
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9I\  
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public static void main(String[] args) m/<F 5R  
{ &8Jg9#  
new TestMethod(); &vFqe,Z  
} q M_/  
} ,jbGM&.C  
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