http断点续传简单实现（java)

/* ]
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**SiteFileFetch.java B*~5)}1op  
*/ 2*N_5&9mE  
package NetFox; BWrv%7  
import java.io.*; !2z?YZhu  
import java.net.*; ?gPKcjgoH!  
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public class SiteFileFetch extends Thread { \MK*by  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Hewd4k  
long[] nStartPos; //开始位置 ' j6gG  
long[] nEndPos; //结束位置 FJ %  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _>=L>*  
long nFileLength; //文件长度 vTaJqEE  
boolean bFirst = true; //是否第一次取文件 $b<6y/"  
boolean bStop = false; //停止标志 =xsTDjH>  
File tmpFile; //文件下载的临时信息 ovwQ2TuK  
DataOutputStream output; //输出到文件的输出流
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F[
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public SiteFileFetch(SiteInfoBean bean) throws IOException MB%Q WU  
{ {0;3W7  
siteInfoBean = bean; iSFuT7;%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xGU(n_Y  
if(tmpFile.exists ()) Qc[3Fq,f  
{
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bFirst = false; kN%MP6?J  
read_nPos(); &AlJ "N|  
} A<6%r7&B'  
else q~@]W=  
{ eeHP&1= 7  
nStartPos = new long[bean.getNSplitter()]; S.Z9$k%  
nEndPos = new long[bean.getNSplitter()]; M[z)6.  
} F q!fWl  
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} e5.h ?  
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public void run() =l.+,|ZH!  
{ etd&..]J  
//获得文件长度 *26334B.R  
//分割文件 rJa$9B*^  
//实例FileSplitterFetch "+zCS|   
//启动FileSplitterFetch线程 sP-^~ pp  
//等待子线程返回 9}c8Xt^&  
try{ XxDaz1  
if(bFirst) wHIj<"2  
{ %?aS#4jI  
nFileLength = getFileSize(); pGSai&  
if(nFileLength == -1) [w\9as/ E  
{ mKT>,M  
System.err.println("File Length is not known!"); sz @p_Z/  
} A<\JQ  
else if(nFileLength == -2) A/7X9ir  
{ H33i*][H  
System.err.println("File is not access!"); Ne$"g[uFU  
} ?=VOD#)  
else UxD5eJJ  
{ Kf 2jD4z}  
for(int i=0;i<nStartPos.length;i++) fK&e7j`qO  
{ @:tj<\G]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); S!PzLTc  
} +dBz`WD  
for(int i=0;i<nEndPos.length-1;i++) '+ xu#R
  
{ [xh*"wT#g  
nEndPos = nStartPos[i+1]; 8vuCc=  
} saU]`w_Z*  
nEndPos[nEndPos.length-1] = nFileLength; OEPa|rb  
} }|B=h  
} 2"fO6!hh  
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//启动子线程 ?:|-Dq,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |v[Rp=?]  
for(int i=0;i<nStartPos.length;i++) q~L^au8  
{ w_ 
{,<[#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~Ph\Sbp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0aoHKeP  
nStartPos,nEndPos,i); )HD`O~M>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `:O\dN>ON  
fileSplitterFetch.start(); J(#mtj>v_  
} @\w,otT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]#/4Y_d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }tPk@$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m^_6:Q0F!8  
nEndPos = " + nFileLength); '!P"xBVAu  
// fileSplitterFetch[nPos.length-1].start(); M0|'f'  
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//等待子线程结束 cECi')  
//int count = 0; jKZt~I  
//是否结束while循环 XhdSFxW}  
boolean breakWhile = false; \([WH!7  
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while(!bStop) o$C|J]%  
{ ?R-9W+U%f  
write_nPos(); qzFQEepso  
Utility.sleep(500); #k<":O  
breakWhile = true; _MWM;f`b  
j#0j)k2Q  
7ZUiY  
for(int i=0;i<nStartPos.length;i++) y<XlRTy[}  
{ $|KaBx1  
if(!fileSplitterFetch.bDownOver) ;NV'W]  
{ L:M0pk{T  
breakWhile = false; V@d)?T  
break; PuxK?bwC  
} x90jw$\%7  
} *?yJkJ"  
if(breakWhile) 1!p/6  
break; Px5t,5xT8  

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//count++; kl1Y] ?z}  
//if(count>4) e75UMWaeC  
// siteStop(); <Fs-3(V+\  
} _,6f#t  
,}
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System.err.println("文件下载结束！"); 6zIgQ4Bp24  
} kC$&:\Rh  
catch(Exception e){e.printStackTrace ();} u)Q;8$`  
} 4R>zPEo  
o2-@o= F  
}a&mY^  
//获得文件长度 R7~Yw*#,  
public long getFileSize() 5&CDHc7Oj  
{ rZ_>`}O2  
int nFileLength = -1; i.iio-  
try{ kllQca|$4  
URL url = new URL(siteInfoBean.getSSiteURL()); oKFT?"[X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JO@Bf  
httpConnection.setRequestProperty("User-Agent","NetFox"); O`cu_  
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int responseCode=httpConnection.getResponseCode(); ? 81X  
if(responseCode>=400) '?o9VrO  
{ Wv!<bT8r  
processErrorCode(responseCode); N0n^L|(R  
return -2; //-2 represent access is error d~ng6pA  
} nY `2uN~9  
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String sHeader; %Hi~aRz  
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for(int i=1;;i++) %K 4  
{ DE{h
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h5|.Et  
//Utility.log(in.readLine()); 2aNT#J"_  
sHeader=httpConnection.getHeaderFieldKey(i); F5gObIJtuY  
if(sHeader!=null) YpdNX.P,  
{ FM^9
}*  
if(sHeader.equals("Content-Length")) HTz+K6&  
{ c\cZ]RZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P\~{3U  
break; ]*%+H|l  
} f?Bj _z  
} q]4pEip  
else K2'O]#  
break; K.>wQA&  
} -ewQp9)G  
} @?B6aD|jE  
catch(IOException e){e.printStackTrace ();} Q^eJ4{Ya:  
catch(Exception e){e.printStackTrace ();} E@QA".  
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Utility.log(nFileLength); dc0@Y  
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return nFileLength; CfT/R/L  
} f1{z~i9@$  
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;~zNqdlH  
//保存下载信息（文件指针位置） sDiHXDI_m  
private void write_nPos() FT\?:wpKa  
{ h:qHR] 8dZ  
try{ X=p"5hhfn  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $v;dV@tB  
output.writeInt(nStartPos.length); WXUkuO  
for(int i=0;i<nStartPos.length;i++) +p:Y=>bTj  
{ eE:&qy^  
// output.writeLong(nPos); LhJa)jFQ  
output.writeLong(fileSplitterFetch.nStartPos); 1]4^V7y  
output.writeLong(fileSplitterFetch.nEndPos); |ek ak{js  
} ?;7b*Z  
output.close(); :iY$82wQ  
} b^V'BC3  
catch(IOException e){e.printStackTrace ();} PjqeE,5  
catch(Exception e){e.printStackTrace ();} XYbyOM VI  
} ?{J!#`tfV  
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}VRvsZ  
//读取保存的下载信息（文件指针位置） 9zKBO* p`  
private void read_nPos() Iz\1
~  
{ Z>A{i?#m  
try{ -$4kBYC l+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -6EK#!+  
int nCount = input.readInt(); H/cTJ9zz  
nStartPos = new long[nCount]; h_ !>yK  
nEndPos = new long[nCount]; Q .RO  
for(int i=0;i<nStartPos.length;i++) jMpa?Jp1  
{ :\}U9QfCw  
nStartPos = input.readLong(); #1Z7&#R/  
nEndPos = input.readLong(); -l*A  
} \aSz2lxEHn  
input.close(); ZCiY,;c  
} oKKz4  
catch(IOException e){e.printStackTrace ();} )+~E8yK  
catch(Exception e){e.printStackTrace ();} 9Vh
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} .)PqN s:  
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private void processErrorCode(int nErrorCode) Rl@$xP  
{ -zC]^Ho@  
System.err.println("Error Code : " + nErrorCode); hLuJWjCV  
} yFe
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//停止文件下载 pt!'v$G/*  
public void siteStop() n9}RW;N+u  
{ YF[$Q=7.
 
bStop = true; pC^[[5A  
for(int i=0;i<nStartPos.length;i++) Cd~LsdKE5  
fileSplitterFetch.splitterStop(); v}`1)BUeF
 
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} 8M
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} @ ^.*$E5  
//负责部分文件的抓取 ,/o(|sks  
**FileSplitterFetch.java %8D?$v"#Z  
*/ 1X@b?6  
package NetFox; sc 
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import java.io.*; BlaJl[Piv  
import java.net.*; jH0Bo;  
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public class FileSplitterFetch extends Thread { ,ep9V,+|  
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String sURL; //File URL qX@9N=g`#O  
long nStartPos; //File Snippet Start Position w6U @tW  
long nEndPos; //File Snippet End Position +qE']yzm!  
int nThreadID; //Thread's ID Bcaw~WD  
boolean bDownOver = false; //Downing is over bF6gBM@*  
boolean bStop = false; //Stop identical plku-O;]  
FileAccessI fileAccessI = null; //File Access interface dQ6GhS~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Wm>b3:  
{ Q7k.+2  
this.sURL = sURL; QNJ\!+,HV  
this.nStartPos = nStart; tR O IBq|  
this.nEndPos = nEnd; CKC0{J8g  
nThreadID = id; 4<Kgmy  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 F@<MT<TRf  
} X%`KYo%  
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public void run() #~e9h9  
{ ,i![QXZ  
while(nStartPos < nEndPos && !bStop) {G.jB/  
{ Z:^3Fm->+  
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$ w]  
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try{ >)sqh ~P  
URL url = new URL(sURL); |8'B/ p=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,RN|d0dE
 
httpConnection.setRequestProperty("User-Agent","NetFox"); ^H'kHl'F  
String sProperty = "bytes="+nStartPos+"-"; M
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httpConnection.setRequestProperty("RANGE",sProperty); u\w2S4c  
Utility.log(sProperty); J!<#Nc  
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InputStream input = httpConnection.getInputStream(); Mk "vvk  
//logResponseHead(httpConnection); a 8-;   
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byte[] b = new byte[1024]; z5ZKks   
int nRead; ]umZJZ#Y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *
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{ -fQX4'3R  
nStartPos += fileAccessI.write(b,0,nRead); *I/A,#4r  
//if(nThreadID == 1) gPp(e j7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /.)2d8,  
} )-)pYRlO  
,5:![  
' 3VqkQ4  
Utility.log("Thread " + nThreadID + " is over!"); PC0HH  
bDownOver = true; O(Td:Zdp  
//nPos = fileAccessI.write (b,0,nRead); '2xcce#  
} <vLdBfw&N  
catch(Exception e){e.printStackTrace ();} i :EO(`  
} c _p[yS  
} R(GmU4  
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//打印回应的头信息 g~|y$T  
public void logResponseHead(HttpURLConnection con) R9q0,yQW
 
{ ;x16shH   
for(int i=1;;i++) !c."   
{ <L2GUX36#
 
String header=con.getHeaderFieldKey(i); }M?|,N6  
if(header!=null) {YBl:r
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'D
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Utility.log(header+" : "+con.getHeaderField(header)); a>?p.!BM  
else ]p\u$VY9  
break; 15JsmA*Q  
} <B=[hk!  
} {9Xm<}%u]]  
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public void splitterStop() Eh {up  
{ *F|i&2  
bStop = true; /Go>5B>  
} f!EOYowW  
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} (< :mM  
|;~nI'0O])  
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/*  I}rGx  
**FileAccess.java h&q=I.3O|?  
*//文件访问(定位，写) 7^&lbzVbm(  
package NetFox; R~!\-6%_  
import java.io.*; / Z1Wy-Z  
'%);%y@v  
prqT(1  
public class FileAccessI implements Serializable{  u*U_7Uw$  
OCwW@OC +  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 qT"drgpi3  
RandomAccessFile oSavedFile; R/Tj^lM  
long nPos; cB_pyX9Z  
r)c+".0d^  
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public FileAccessI() throws IOException An/>05|  
{ 9}.,2JE  
this("",0); j6RJC  
} Lblet  
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public FileAccessI(String sName,long nPos) throws IOException 6W]OpM  
{ QN3qF|))  
oSavedFile = new RandomAccessFile(sName,"rw"); :a=ro2NH  
this.nPos = nPos; ^M[#^wv,  
oSavedFile.seek(nPos); =A$Lgk>|  
} GA(OK-WUd  
4P`PmQ=GQh  
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public synchronized int write(byte[] b,int nStart,int nLen) <=$rU232}  
{ SgyqmYTvZw  
int n = -1; 23)F-.C}j  
try{ E1^aAlVSD  
oSavedFile.write(b,nStart,nLen); =7F
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n = nLen; !p-'t]  
}
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catch(IOException e) f%vHx,
  
{ =_K%$y*  
e.printStackTrace (); G~JCgi  
} _'H2>V_  
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return n; 'uws  
} ,\BfmC_i  
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} u![4=w  
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/* u4go*#  
**SiteInfoBean.java }~myf\$  
*/ <ur KIu  
package NetFox; T_3V/)%@  
}P05eI  
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public class SiteInfoBean { 3s3a>  
58M'r{8_  
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private String sSiteURL; //Site's URL qPp1:a"   
private String sFilePath; //Saved File's Path Tbe_xs^  
private String sFileName; //Saved File's Name 7yo|ie@S  
private int nSplitter; //Count of Splited Downloading File 1-4   
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public SiteInfoBean() rd|@*
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{//nSplitter的缺省值为5 bv.EM  
//default value of nSplitter is 5 $
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this("","","",5); /&~nM  
} NvXj6U*%  
|U8>:DEl  
6lB{Ao?|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {KF7j63  
{ nL 1IS  
sSiteURL= sURL; XMjI}SPG  
sFilePath = sPath; p=:7 atE  
sFileName = sName; s#'|{  
this.nSplitter = nSpiltter; "
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6^7)GCq [  
} U'JP1\  
Y9z:xE  
s98: *o3  
public String getSSiteURL() D<+ bzC  
{ U)&H.^@r$  
return sSiteURL; $M:4\E5(  
} [V!^\g\6  
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 9OrA9r  
public void setSSiteURL(String value) FE$M[^1_  
{ 9$B)hrJo  
sSiteURL = value; -~QlHp&SY  
} f 3nnXE"  
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<) >gg!  
public String getSFilePath() fY|@{]rx  
{ v*vub#wP  
return sFilePath; D'HL /[@`  
} ` 4s#5g  
>=Rd3dgDG  
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public void setSFilePath(String value) d +*T@k]>M  
{ 17MN8SfQ  
sFilePath = value; )W_ Y3M,  
} ,*9#c
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=RCfibT!C  
;/6:lL  
public String getSFileName() "B_5Y&pM`  
{ Zq2H9^![y~  
return sFileName; g7E`;&f  
} ONg<  
~m,mvRS  
\?5[RR  
public void setSFileName(String value) JCCx 5  
{ :O>Nd\UtO  
sFileName = value; z9OMC$,V  
} K-g=td/@  
&;uGIk>s  
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public int getNSplitter() ss|6_H =  
{ >o=axZNa  
return nSplitter; (_s!,QUe  
} -7C=- \]  
(AyRs7Dkn  
hs -}:^S`  
public void setNSplitter(int nCount) #U6/@l)  
{ 93zlfLS0  
nSplitter = nCount; j,gM+4V^  
} 7+A-7ci  
} _S%OX_UMn^  
\k$]GK-  
.PA?N{z  
/* -Y!=Iw 4  
**Utility.java dxae2 tV  
*/ )nbyV a  
package NetFox; Z;dwn~Tw  
rsq'60  
H7cRWB  
public class Utility { NZi'eZ{^`  
\a~;8):q=i  
XH_qA[=c]  
public Utility() Q>+_W2~]  
{ hH|XtQ.n^  
s]V{}bY`  
$yxIE}  
} CO6XIgTe  
zL[U;  
//线程睡眠 @N:3`[oB  
public static void sleep(int nSecond) m8j#{[NE  
{ :jN;l  
try{ G41$oalQ1  
Thread.sleep(nSecond); G1n>@Y'j''  
} g'l7Jr3  
catch(Exception e) Q%b46"  
{ vp9E}ga  
e.printStackTrace (); C9^elcdv  
} *< SU_dAh  
} N]<~NG:6b  
F0o18k_"  
//日志 Ov{B-zCA  
public static void log(String sMsg) J3!k*"P  
{ f|HgLFx  
System.err.println(sMsg); 8mQd*GGu1  
} 5Dh&ez`oR'  
$(<*pU  
-^SD6l$  
public static void log(int sMsg) )I0g&e^Tzy  
{ b "AHw?5F  
System.err.println(sMsg); v*T@<]f3j  
} ;tIIEc  
} 0$dY;,Q.  
'rcsK  
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/* XQ?)  
**TestMethod.java W1M/Z[h6)5  
*/ KTS7)2ci  
package NetFox; 4 9+}OIX  
c+ H)1Dfq  
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public class TestMethod { ~NJLS-  
hJtghG6v  
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public TestMethod() l.t.,:  
{ ///xx/weblogic60b2_win.exe 5Qe
}v  
try{ Y_ u7 0@`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?\ i,JJO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QH56tQq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); VE+p&0  
fileFetch.start(); ohG43&g~  
} zJym`NF  
catch(Exception e){e.printStackTrace ();} ?eZ"UGZg'  
boHm1hPKS  
8C4@V[sm`  
} B\~3p4S  
=?QQb>  
"nS{ ;:  
public static void main(String[] args) ieK'<%dxF  
{ ]&%X(jWyn  
new TestMethod(); pz z`4VS:  
} 6-E4)0\  
} sRI=TE]s  
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