http断点续传简单实现（java)

/* u66TrYStG  
**SiteFileFetch.java uMljH@xBc  
*/ RI7qsm6RN  
package NetFox; :5q^\xmmq  
import java.io.*; rerUM*0  
import java.net.*; 9J't[( u|u  
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public class SiteFileFetch extends Thread { rcD.P?"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean n3-GnVC][  
long[] nStartPos; //开始位置 4+Li)A:4.  
long[] nEndPos; //结束位置 p7?CeyZ-V  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k:&?$  
long nFileLength; //文件长度 N
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boolean bFirst = true; //是否第一次取文件 ^Y1AeJ$L  
boolean bStop = false; //停止标志 eP-R""uPw  
File tmpFile; //文件下载的临时信息 r? 6Z1  
DataOutputStream output; //输出到文件的输出流 8+@1wk
s  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Xuz8"b5^Zx  
public SiteFileFetch(SiteInfoBean bean) throws IOException OgzGkc@A  
{ nA{ncTg1\  
siteInfoBean = bean; ][T9IAn  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fJ|Bu("N  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3"2<T^H]  
if(tmpFile.exists ()) n]kQ
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{ v)v{QNQp^  
bFirst = false; %BT)oH}  
read_nPos(); Gx~"iM  
} -Ihn<<uE?  
else =X%R*~!#Of  
{ {!:|.!-u  
nStartPos = new long[bean.getNSplitter()]; qW`XA  
nEndPos = new long[bean.getNSplitter()]; 8xeun~e"vS  
} ^HOwN<}`#  
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} 7oqn;6<[>,  
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public void run() O #p)~V8~  
{ \|b1s @c8  
//获得文件长度 HCe-]nMd  
//分割文件 >k&lGF<nl  
//实例FileSplitterFetch D; 35@gtj  
//启动FileSplitterFetch线程 *6\`A!C  
//等待子线程返回 "c
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try{ l,FG:"`Z@  
if(bFirst) v=yI#
5  
{ '8kL1  
nFileLength = getFileSize(); R;Ix<y{U  
if(nFileLength == -1) <}x|@u  
{ a\HtxR8L  
System.err.println("File Length is not known!"); a_#eGe>  
} )eedfb1
  
else if(nFileLength == -2) 7+2aG  
{ "351s3ff  
System.err.println("File is not access!"); "l2N_xX;  
} ,a?\i JNb  
else 3!L<=X  
{ ju2X*  
for(int i=0;i<nStartPos.length;i++) N4GIb 6  
{ _R!!4Hp<Q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); AQBx k[  
} vGLb2Q  
for(int i=0;i<nEndPos.length-1;i++) kod_ 1L
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{ Ivgwm6M  
nEndPos = nStartPos[i+1];  "lnk  
} %+OPas8C  
nEndPos[nEndPos.length-1] = nFileLength; Dm`U|<o  
} #}]il0d  
} [8J}da}  
~>-;(YU"t  
BrH`:Dw  
//启动子线程 *]UEF_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $!3t$-TSD  
for(int i=0;i<nStartPos.length;i++) uC8T!z  
{ !v;_@iW3e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v(nQd6;T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), M&\?)yG  
nStartPos,nEndPos,i); o5G"J"vxe  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~X(xa  
fileSplitterFetch.start(); (/P&;?j  
} kp>Z/kt  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !?-5hh1\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); YGO7lar  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \rnG 1o  
nEndPos = " + nFileLength); s/&]gj"  
// fileSplitterFetch[nPos.length-1].start(); 0*M}QXt  
qN,FX#DP  
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//等待子线程结束 %IXW|mi  
//int count = 0; A-`J!xj#/  
//是否结束while循环 Ewsg&CCN  
boolean breakWhile = false; aZCT|M1  
_!p$47  
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while(!bStop) r{jD,x2  
{ 1Moh`  
write_nPos(); /g7?,/vnZ  
Utility.sleep(500); b1^Yxe#L  
breakWhile = true; %~(i[Ur;  
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for(int i=0;i<nStartPos.length;i++) 2 3w{h d  
{ D ;I;,Z  
if(!fileSplitterFetch.bDownOver) O7*i;$!R  
{ iC2n
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breakWhile = false; yC*BOJS  
break; 5&K
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} cyeDZ)  
} jz:c)C&/  
if(breakWhile) Q31c@t  
break; TN_$E&69I  
;!sGfrs0$  
7f,WzvV  
//count++; shvcc  
//if(count>4) $s!meg@s  
// siteStop(); Dx)XC?'xO  
} z5'nS&x  
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System.err.println("文件下载结束！"); }Cg~::,"  
} )B4c;O4t  
catch(Exception e){e.printStackTrace ();} ^C|9K>M  
} 2` qXDfD`  
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//获得文件长度 e/\_F+jyc  
public long getFileSize() gi >{`.]  
{ EIm\!'R]  
int nFileLength = -1; cLP@0`^H  
try{ AE _~DZ:%c  
URL url = new URL(siteInfoBean.getSSiteURL()); !S{<Xc'wv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >L4$DKO  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7?] p\`  
}dl(9H=4  
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int responseCode=httpConnection.getResponseCode(); :h~!#;w_  
if(responseCode>=400) B[V=l<J  
{ _,~zy9{,  
processErrorCode(responseCode); f'U]Ik;Jy  
return -2; //-2 represent access is error S}O\<6&  
} u)pBFs<dn  
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String sHeader; RfRaWbn  
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for(int i=1;;i++) _"V0vV  
{ lsi8?91  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &0`7_g7G  
//Utility.log(in.readLine()); &r%3)Z8Et  
sHeader=httpConnection.getHeaderFieldKey(i); UC@"<$'C  
if(sHeader!=null) pC8i&_A  
{ v%[mt`I  
if(sHeader.equals("Content-Length")) Q2=~  
{ 9Z 4R!Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :g";p.~=  
break; XU7bWafy  
} >m!.l{*j>N  
} q4=RE  
else hNy S  
break; -AQX-[
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} 0
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} X9HI@M]h  
catch(IOException e){e.printStackTrace ();} OpQa!  
catch(Exception e){e.printStackTrace ();} IIZsN*^  
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Utility.log(nFileLength); wQc w#  
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return nFileLength; gKCIfxM  
} "Wp<^ssMo  
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//保存下载信息（文件指针位置） KK6YA  
private void write_nPos() ?Dm&A$r  
{ qfU3Cwy  
try{ 0*^Fk=>ej  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (tvh9o  
output.writeInt(nStartPos.length); nabN.Ly  
for(int i=0;i<nStartPos.length;i++) L?fv5 S3  
{ !w Bmf&=  
// output.writeLong(nPos); .$iIr:Tc>  
output.writeLong(fileSplitterFetch.nStartPos); SH.'E Hd  
output.writeLong(fileSplitterFetch.nEndPos); U<b!$"P9  
} 2}twt  
output.close(); icmDPq  
} |sh U  
catch(IOException e){e.printStackTrace ();} 3[rB:cE/  
catch(Exception e){e.printStackTrace ();} [6|vx},N  
} NL 37Y{b  
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ks}o9[D3  
//读取保存的下载信息（文件指针位置） 51
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private void read_nPos() :y)'qv[  
{ FcA0 \`0M  
try{ p* @L1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i`~y%y  
int nCount = input.readInt(); J"y@n~*0  
nStartPos = new long[nCount]; bBX~ZWw
  
nEndPos = new long[nCount]; jVz1`\Nje  
for(int i=0;i<nStartPos.length;i++) '<Gqu_-  
{ @j6D#./7j  
nStartPos = input.readLong(); UL/>t}AG  
nEndPos = input.readLong(); P7b2I=t
 
} ,o)MiR9-[A  
input.close(); ,n*.Yq  
} 5kF5`5+Vj  
catch(IOException e){e.printStackTrace ();} _*9Zp1r  
catch(Exception e){e.printStackTrace ();} d:D2[  
} 1;W>ceN"  
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private void processErrorCode(int nErrorCode) 4]bTO  
{ 
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System.err.println("Error Code : " + nErrorCode); L*z;-,  
} hk I$ow(  

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//停止文件下载 G\Me%{b#  
public void siteStop() S%@$J~\rx  
{ IQDWH/c  
bStop = true; |Xag:hof  
for(int i=0;i<nStartPos.length;i++) UTPl7po5D  
fileSplitterFetch.splitterStop(); TO.NCO\x  
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} v>XE]c_  
} dZW:Cf 9K  
//负责部分文件的抓取 n>HNpy  
**FileSplitterFetch.java Vr*t~M>  
*/ 1}6pq2  
package NetFox; -cKR15  
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import java.io.*; ;VuIQ*@m"  
import java.net.*; <R2  
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public class FileSplitterFetch extends Thread { Ol? 2Qy.2)  
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String sURL; //File URL V/Q6v YX  
long nStartPos; //File Snippet Start Position /a q%l]hQ@  
long nEndPos; //File Snippet End Position P}5aN_v\  
int nThreadID; //Thread's ID *%O1d.,  
boolean bDownOver = false; //Downing is over _5zR!|\^  
boolean bStop = false; //Stop identical -K jCPc  
FileAccessI fileAccessI = null; //File Access interface 9hv\%_>o  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i`Tne3)  
{ ]HRZ9oP  
this.sURL = sURL; c_iF S  
this.nStartPos = nStart; vl#/8]0!  
this.nEndPos = nEnd; 3t,SXI@  
nThreadID = id; m[}$&i$(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BjH(E'K[b  
} $OT:J  
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public void run() zme:U![  
{ 0h7\zoZ5  
while(nStartPos < nEndPos && !bStop) 1)r1/0  
{ ,y0kzwPR1  
;#;X@BhS  
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try{ y?rsfIth`  
URL url = new URL(sURL); s#Le`pGo
W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6+It>mnR  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~DJ/sY2/  
String sProperty = "bytes="+nStartPos+"-"; ;'h7 j*6  
httpConnection.setRequestProperty("RANGE",sProperty); r=9*2X#  
Utility.log(sProperty); )S%mKdOm $  
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InputStream input = httpConnection.getInputStream(); ?*T`a oB  
//logResponseHead(httpConnection); +z4NxR   
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byte[] b = new byte[1024]; cq0jM;@d  
int nRead; ]8mBFr5E9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %:??QD*  
{ wy^>i$
TC  
nStartPos += fileAccessI.write(b,0,nRead); j'7FTVmJ  
//if(nThreadID == 1) 6wF?FtT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8\yH7H  
} #*9*[Xbi  
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Utility.log("Thread " + nThreadID + " is over!"); JK1b68n  
bDownOver = true; I[&!\Me[+w  
//nPos = fileAccessI.write (b,0,nRead); t*DM^
.@  
} Fc=8Qt^  
catch(Exception e){e.printStackTrace ();} ht1 jrCe  
} U'\\(m|  
} =3}+f-6"'  
C}!$'C|  
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//打印回应的头信息 GJ*AyYG  
public void logResponseHead(HttpURLConnection con) mV;7SBoT  
{ B^6P6,  
for(int i=1;;i++) 2<y -cQ?>  
{ ^iGIF~J9  
String header=con.getHeaderFieldKey(i); GxvVh71zP  
if(header!=null) @}FRiPo6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ULoTPx@N  
Utility.log(header+" : "+con.getHeaderField(header)); .z
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else 2/;
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break; vj#gY2qZ  
} 4 Hu+ljdjB  
} jReI+ pS  
vv3dr_l:  
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public void splitterStop() 3{:d$- y  
{ M~@\x]p >  
bStop = true; akNJL\b  
} v.\&gn(  
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} ]AN)
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/* 9_HEImk  
**FileAccess.java '8}\! i&  
*//文件访问(定位，写) cd:O@)i  
package NetFox; AD8~  
import java.io.*; Y&#<{j':  
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N%^mR>.`  
public class FileAccessI implements Serializable{ ?"L>jr(  
9 /9,[A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h<6r+*T' p  
RandomAccessFile oSavedFile; E[$['0  
long nPos; @ #V31im"N  
)Dv"seH.  
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public FileAccessI() throws IOException oXGf#>keg  
{ C#gQJ=!B  
this("",0);  R
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} U_14CLsdG  
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public FileAccessI(String sName,long nPos) throws IOException YpuA,r;"  
{ H-I*;  
oSavedFile = new RandomAccessFile(sName,"rw"); Ue8_Q8q5  
this.nPos = nPos; ; I=z  
oSavedFile.seek(nPos); E fqa*,k  
} ;T/' CD  
~kYF/B2*  
RRV&!<l@$  
public synchronized int write(byte[] b,int nStart,int nLen) ,PY<AI^59  
{ H9&?<j1n  
int n = -1;
SH5k^EJ  
try{ C@KYg/nYw  
oSavedFile.write(b,nStart,nLen); 4E"qpy \(  
n = nLen; t);5Cw
_  
} Cu!4ha.e`  
catch(IOException e) o]jo R3  
{ ~L?p/3m   
e.printStackTrace (); :pNZQX  
} >+8mq]8^  
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return n; y_J{+  
} TN l$P~X>  
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kn  
} LxMOs Nv  
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q/]tJ{FI  
/* b
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**SiteInfoBean.java rPQ$e!m1Ee  
*/ Th"7p:SE?  
package NetFox; r"rEVx#1=  
,E/vHI8  
!&#CEF@J  
public class SiteInfoBean { xv1$,|^ts  
HI:E&20y  
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private String sSiteURL; //Site's URL ujwI4oj"c  
private String sFilePath; //Saved File's Path "ebn0<cZ  
private String sFileName; //Saved File's Name +LrW#K;  
private int nSplitter; //Count of Splited Downloading File h#;yA"j1&  
}P^n /  

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public SiteInfoBean() p-ry{"XA  
{//nSplitter的缺省值为5 ]Q^oc  
//default value of nSplitter is 5 GTLlQy)'=  
this("","","",5);  f0:)  
} ZtIK"o-|!  
L@v0C)
  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j^LnHVHk1  
{ Xf#uK\f  
sSiteURL= sURL; j8N
8|\n-  
sFilePath = sPath; fDqlN`P@  
sFileName = sName; smk0*m4  
this.nSplitter = nSpiltter; Ot v{#bB$  
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} `.><$F  
k ^+h>B-;  
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public String getSSiteURL() `GH6$\:  
{ ncihc$V<  
return sSiteURL; >o(*jZ  
} CuDU~)`  
SR8[ 7MU  
w}7`Vas9  
public void setSSiteURL(String value) w/ZV9"BhE  
{ FUMAvVQ  
sSiteURL = value; viKN:n! Ev  
} =L&_6lb  
[;};qQ-C2  
l1YyZ^Z  
public String getSFilePath() BhNwC[G?m  
{ $z` jR*  
return sFilePath; 6s>PZh  
} Qza[~6  
8B\,*JGY2  
3):7mE(  
public void setSFilePath(String value) I8?egDkk  
{ 6:QJ@j\  
sFilePath = value; GY0<\-  
} 8f#YUK sW=  
EMJ}tvL0Tp  
1=#`&f5f&  
public String getSFileName() gSC8qip  
{ =(v/pLLK?  
return sFileName; -Xx,"[sN\w  
} o'R_kadN[T  
K@W~  
IgSe%B  
public void setSFileName(String value) .8g&V|  
{ R:OoQ^c  
sFileName = value; 6eQrupa  
} T*'5-WV|3t  
=g?r.;OO  
Hs2L$TX  
public int getNSplitter() XbG=H-|  
{ !'n+0  
return nSplitter; Qg1LT8  
} 2R.YHj  
4|x5-m+T  
J]$%1Y  
public void setNSplitter(int nCount) {"s9A&  
{ Y$Fbi2A4  
nSplitter = nCount; ]}C#"Xt  
} V$^x]z  
} [gD02a:u  
vO <;Gnh~  
zoO>N'b3)  
/* u!;kBs  
**Utility.java #F[6$. Gr  
*/ Cc9<ABv?  
package NetFox; gM_Z/$  
Qb9) 1  
vzs6YsA  
public class Utility { )WuuU [(  
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Bxz{rR0XV  
public Utility() -08Ys c  
{ h&[!CtPm  
)V~<8/)  
<9B43  
} Vs m06Rj{  
bm(0raugs  
//线程睡眠 ^Fy) oWS  
public static void sleep(int nSecond) Tf*X\{"  
{ |+ @  
try{ p5>TL!4M  
Thread.sleep(nSecond); mN*9X[>x  
} Cl i k  
catch(Exception e) '[:].?M  
{ {.eC"  
e.printStackTrace (); nhQ.U>&-M  
} 9?l( }S`  
} (#7pGGp*E  
w QwY_ _  
//日志 #P18vK5  
public static void log(String sMsg) =yfr{5}R  
{ 7zpwP  
System.err.println(sMsg); &#`d8}3D  
} <S TwylL  
JA())0a  
Q8T4_p[-o  
public static void log(int sMsg) \-
`L}$  
{ E70
 
System.err.println(sMsg); NAHQ:$  
} Xs*~[k'  
} Mx0c #d.  
7ugmZO}lL  
@
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/* I0GL/a4s  
**TestMethod.java Eq'YtqU  
*/ Y"G$^3% (]  
package NetFox; Koahd=  
aD24)?db-  

H~@aT7  
public class TestMethod { &UQKZ.  
wf<uG|90  
{I`B?6K5  
public TestMethod() Iu%/~FgPj{  
{ ///xx/weblogic60b2_win.exe ApjLY58=  
try{ j&[63XSe  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); I3s'44  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); SAly
~(r?/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |M0 XLCNd_  
fileFetch.start(); st'Y j  
} ZVgR7+`]#  
catch(Exception e){e.printStackTrace ();} 5as';1^P&*  
HwM:bY N  
~d){7OG  
} )Q~Q.  
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|LiFX5!\  
public static void main(String[] args) s^js}9]p  
{ 9]7+fu  
new TestMethod(); DEqk9Exk`  
} $aG]V-M>  
} |`_TVzA  
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