http断点续传简单实现（java)

/* IW
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**SiteFileFetch.java Yw<:I&  
*/ 8=9sIK2  
package NetFox; ]Ox.6BKjDP  
import java.io.*; ENzeVtw0  
import java.net.*; \tqAv'jA|  
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public class SiteFileFetch extends Thread { c[$oR,2b13  
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*?+!(E  
SiteInfoBean siteInfoBean = null; //文件信息Bean \^cn}db)  
long[] nStartPos; //开始位置 WXL.D_=+  
long[] nEndPos; //结束位置 nLg7A3[1v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [PT_y3'%  
long nFileLength; //文件长度 5sE}B8 mF  
boolean bFirst = true; //是否第一次取文件 vrGNiGIi[  
boolean bStop = false; //停止标志 K3^2R-3:8  
File tmpFile; //文件下载的临时信息 CmZ?uo+Y  
DataOutputStream output; //输出到文件的输出流 s>X;m.<  
10&A3C(E  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） m.*+0NG  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q~kwUZ  
{ u4'Lm+&O  
siteInfoBean = bean; uJ$,e5q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z4goa2@Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G`z48  
if(tmpFile.exists ()) Su7?-vY  
{  lzuZv$K  
bFirst = false; HChewrUAn  
read_nPos(); 7d*<'k]{,  
} s7?kU3y=s  
else ~6nQ-  
{ N_0O""d  
nStartPos = new long[bean.getNSplitter()]; GZw<Y+/V"5  
nEndPos = new long[bean.getNSplitter()]; ElAG~u?  
} e|LXH/H  
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} cPXvTVvs  
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public void run() slx^" BF^  
{ r/e&}!  
//获得文件长度 D
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//分割文件 Q7\Ax0  
//实例FileSplitterFetch jDoWSYu4tY  
//启动FileSplitterFetch线程 %WNy=V9txp  
//等待子线程返回 N?XN$hwdZ  
try{ ,]MX&]  
if(bFirst) Ou%>Dd5|?  
{ bCF63(0  
nFileLength = getFileSize(); lFcCWy  
if(nFileLength == -1) KlPH.R3MPO  
{ w~9gZ&hdp  
System.err.println("File Length is not known!"); Z%Gvf~u  
} R&QT  'i  
else if(nFileLength == -2) 8/CGg_C1  
{ 9(_/jU4mc  
System.err.println("File is not access!"); 0)B+:  
} MouYZI)  
else KK+Mxoj,  
{ 0-9&d(L1g  
for(int i=0;i<nStartPos.length;i++) $ ]HIYYs  
{ Du/s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [D)A+  
} d2Y5'A0X  
for(int i=0;i<nEndPos.length-1;i++) ICi- iX  
{ DF~w20+  
nEndPos = nStartPos[i+1]; 
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} +Il=gL1  
nEndPos[nEndPos.length-1] = nFileLength; (Gc5lMiX3  
} G\ofg  
} dw-r}Qioe  
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//启动子线程 pd6d(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; e:l 6;  
for(int i=0;i<nStartPos.length;i++) R3~&|>7/T  
{ u-Vn
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r?Vob}'Pt]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), dM') <lF  
nStartPos,nEndPos,i); N%-nxbI\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [Y*UCFhI0  
fileSplitterFetch.start(); 01Aa.i^d(  
} S:d`z'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q3DxjD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !qR(Rn  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0KZ 3h|4lP  
nEndPos = " + nFileLength); _,}Ye,(^=  
// fileSplitterFetch[nPos.length-1].start(); }fhVn;~}8  
>C i=H(8vN  
mF1oY[xa_  
//等待子线程结束 &ke4":7X  
//int count = 0; ";~#epPkX  
//是否结束while循环 /[q@=X&  
boolean breakWhile = false; ,[~EThcq  
l^_X?
L@  
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while(!bStop) f,1rmX1  
{ 5Z:HCp-aG  
write_nPos(); >|s=l`"Xz  
Utility.sleep(500); j@Dy
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breakWhile = true; @sDd:>t  
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for(int i=0;i<nStartPos.length;i++) >Cf`F{X'U  
{ Jx}5`{\  
if(!fileSplitterFetch.bDownOver) GA|q[<U  
{ SbZk{lWcq  
breakWhile = false; |qr[*c3$1  
break; ~`BOzP  
} 6Z"%vrH  
} Wp'\NFe8  
if(breakWhile) D>mLSh  
break; KpE#Ye&  
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//count++; 2
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//if(count>4) i ]_fhC  
// siteStop(); a'\`Mi@rb  
} i~2>kxf;K1  
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System.err.println("文件下载结束！"); \u*,~J)z  
} !y),| #7P  
catch(Exception e){e.printStackTrace ();} )#Id2b~  
} eAqQ~)8^  
l YhwV\3  
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//获得文件长度 n Au>i<  
public long getFileSize() Rl(b tr1w  
{ N*
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int nFileLength = -1; ^;2L`U@5  
try{ }$o%^"[  
URL url = new URL(siteInfoBean.getSSiteURL()); v!x[1[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -or9!:8  
httpConnection.setRequestProperty("User-Agent","NetFox"); R%Z} JR.  
[9L(4F20  
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int responseCode=httpConnection.getResponseCode(); J7xZo=@k  
if(responseCode>=400) bcZuV5F&  
{ A@#dv2JzP  
processErrorCode(responseCode); yT>T Vq/e  
return -2; //-2 represent access is error 6R<%.-qr  
}
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String sHeader; ^TjFR*S'E  
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for(int i=1;;i++) ~}5(J,1!  
{ ,lUo
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); qq/Cn4fN8  
sHeader=httpConnection.getHeaderFieldKey(i); nO/5X>A,Zw  
if(sHeader!=null) {tMD*?C[6  
{ 9O)>>1}*S  
if(sHeader.equals("Content-Length")) itvwmI,m\  
{ 2rH6ap  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]uZH  0  
break; FlZ]R  
} F,W(H@ ~x  
} 8}0 D?  
else gV7o eZ5  
break; E|TzrH  
} -lp_~)j^  
} +2g3%c0}  
catch(IOException e){e.printStackTrace ();} zknD(%a  
catch(Exception e){e.printStackTrace ();} ^T[#rNkeL  
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Utility.log(nFileLength); %{{#Q]]&  
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return nFileLength; H0HYb\TX?  
} %(]rc%ry0  
5(W9Jj]  
+u#x[xO  
//保存下载信息（文件指针位置）  l g
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private void write_nPos() zM'-2,  
{ 1-n
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try{ fP|\1Y?CS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?/wloLS47  
output.writeInt(nStartPos.length); "&%Hb's  
for(int i=0;i<nStartPos.length;i++) 3LmHH =  
{ 9+:Trc\%N
 
// output.writeLong(nPos); BCbW;w8aI  
output.writeLong(fileSplitterFetch.nStartPos); fwEi//1  
output.writeLong(fileSplitterFetch.nEndPos); d !H)voX  
} jt3SA [cy  
output.close(); K+\hv~+@  
} ?Y9?x,x  
catch(IOException e){e.printStackTrace ();} ".\(A f2  
catch(Exception e){e.printStackTrace ();} )N/KQ[W  
} by<2hLB9Q  
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//读取保存的下载信息（文件指针位置） !S:@x.n@iR  
private void read_nPos() IFY!3^;zO  
{ !=we7vK}  
try{ cMv3` $  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); UQFuEI<1-  
int nCount = input.readInt(); -AE/,@\P  
nStartPos = new long[nCount]; DXt^Ym5Cv  
nEndPos = new long[nCount]; 1<83MO;  
for(int i=0;i<nStartPos.length;i++) v<wT`hiKW  
{ R32d(2%5K  
nStartPos = input.readLong(); z-DpLV  
nEndPos = input.readLong();
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} Jj " {r{  
input.close(); #t O!3=0  
} Pz 'Hqvd  
catch(IOException e){e.printStackTrace ();} ?<;<#JN  
catch(Exception e){e.printStackTrace ();} ?KN_J  
} 3(%,2  
#!/Nmd=Nj  
8'_Y=7b0Nw  
private void processErrorCode(int nErrorCode) LPO" K"'w  
{ w(D9'  
System.err.println("Error Code : " + nErrorCode); {@A2jk\  
} Oq5k4  
5 %Gf?LyO  
v,0DGR~  
//停止文件下载 wLbngO=VG  
public void siteStop() =Ug_1w  
{ .p`'^$X^  
bStop = true; q4{tH  
for(int i=0;i<nStartPos.length;i++) Fn,|J[sC  
fileSplitterFetch.splitterStop(); ]_?y[@ZP  
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)  
} t3G'x1  
} \4k*Zk  
//负责部分文件的抓取 wNZ7(W.U  
**FileSplitterFetch.java In&vh9Lw  
*/ fsd>4t:"\  
package NetFox; .Q@"];wH  
%Qq)=J<H;  
6K}=K?3Z  
import java.io.*; iE(g
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import java.net.*; =HHg:"  
_=5ZB_I  
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public class FileSplitterFetch extends Thread { (#]KjpIK  
k 9rnT)YU  
1tW:(~=a;  
String sURL; //File URL z7C1&bGe  
long nStartPos; //File Snippet Start Position ^q\zC%.  
long nEndPos; //File Snippet End Position Qs:r@"hE  
int nThreadID; //Thread's ID hT"K}d;X  
boolean bDownOver = false; //Downing is over OWsYE?  
boolean bStop = false; //Stop identical e%6{P  
FileAccessI fileAccessI = null; //File Access interface dL(|Y{4  
n b
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lvi:I+VgA  
{ h>0<@UP  
this.sURL = sURL; u2-7vudh  
this.nStartPos = nStart; mC92J@m/L!  
this.nEndPos = nEnd; 6/ipdi[ _  
nThreadID = id; -^v}T/Kl#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Xkom@F~]  
} !`o:+Gg@  
&Q>'U6"%  
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public void run() [dlH t;S  
{ J|S^K kC  
while(nStartPos < nEndPos && !bStop) mcr#Ze  
{ "%*lE0Tx  
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try{ ue<<Y"NR  
URL url = new URL(sURL); P1stL,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F t/ x5  
httpConnection.setRequestProperty("User-Agent","NetFox"); s$x] fO  
String sProperty = "bytes="+nStartPos+"-"; }TJ|d=  
httpConnection.setRequestProperty("RANGE",sProperty); -i5g 8t'  
Utility.log(sProperty); CL :M>(  
2-!Mao"^  
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InputStream input = httpConnection.getInputStream(); k
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//logResponseHead(httpConnection); es+_]:7B9  
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byte[] b = new byte[1024]; cu!bg+,zl  
int nRead; 9Pk3}f)a  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i03}f%JnuO  
{ 3,I >.3  
nStartPos += fileAccessI.write(b,0,nRead); UQ])QTrZFi  
//if(nThreadID == 1) zB" `i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EZQ+HECpK  
} ~PW}sN6ppG  
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Utility.log("Thread " + nThreadID + " is over!"); dIa(</ }  
bDownOver = true; -s%-*K+,W  
//nPos = fileAccessI.write (b,0,nRead); G
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} s8Ry}{  
catch(Exception e){e.printStackTrace ();} V/9"Xmv75  
} ro^6:w3O^  
} "Xk%3\{P  
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J*~2:{=%  
//打印回应的头信息 gq_7_Y/  
public void logResponseHead(HttpURLConnection con) Q=L$7   
{ maUHjI 5A-  
for(int i=1;;i++) }42qMOi#w1  
{ vs])%l%t  
String header=con.getHeaderFieldKey(i); <Z:8~:@  
if(header!=null) %>9+1lUhV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +bc#GzVF  
Utility.log(header+" : "+con.getHeaderField(header)); !QR?\9`  
else a$zm/  
break; 3^R][;  
} tZu*Asx7  
} `Ivw`}L  
Z++Z@J"  
5*wApu{2A  
public void splitterStop() h9BD ^j  
{ a;'E}b{`F  
bStop = true; x #X#V\w=  
} A6UdWK  
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} k CW!m  
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/* Bw]L2=d  
**FileAccess.java 9
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*//文件访问(定位，写) ZCE%38E N  
package NetFox; F'>GN}n  
import java.io.*; a
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public class FileAccessI implements Serializable{ [[?[? V ,  
: >wQwf  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 T7lj39pJq  
RandomAccessFile oSavedFile; n:*_uc^C  
long nPos; vJj:9KcP>h  
2 ]DCF  
7Z`Mt9:Ht  
public FileAccessI() throws IOException N[bR&#p  
{ b1+hr(kMRM  
this("",0); )`s;~_ZZ  
} uH ny ]  
!M]%8NTt2  
Ck3QrfM  
public FileAccessI(String sName,long nPos) throws IOException ?zhI=1ED%  
{ 3Zaq#uA  
oSavedFile = new RandomAccessFile(sName,"rw"); x7KcO0F{  
this.nPos = nPos; e>,9]{N+$  
oSavedFile.seek(nPos); 9QOr,~~s  
} h8#5vO2  
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;h,R?mU  
public synchronized int write(byte[] b,int nStart,int nLen) ;-9zMbte:  
{ 8!uL-_Bn  
int n = -1; T@Ss&eGT2  
try{ cZaF f?]k  
oSavedFile.write(b,nStart,nLen); A{4G@k+#d  
n = nLen; S_|9j{w)  
} 2;%#C!TG;  
catch(IOException e)  `CAG8D  
{ y|e2j&m  
e.printStackTrace (); rb *C-NutE  
} J})$  
@~$F;M=.*  
c_qcb7<~.  
return n; -- i&"  
} \'; t*  
;# R3k  
%="~\1y  
} to!mz\F  
;Na8_}  
nW$A^  
/* S_T{L  
**SiteInfoBean.java &Rt+LN0qB0  
*/ FE8+E\ U?  
package NetFox; ){O1&|z-
 
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Kf05<J!  
public class SiteInfoBean { Jw:Fj{D  
UM4@H1  
#$rf-E5g-K  
private String sSiteURL; //Site's URL 00`bL  
private String sFilePath; //Saved File's Path kZU"Xn  
private String sFileName; //Saved File's Name B^
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private int nSplitter; //Count of Splited Downloading File r~Y>+ln.  
1-6gB@cvQ  
;f".'9 l^
 
public SiteInfoBean() }.fL$,7a  
{//nSplitter的缺省值为5 E/wQ+rv  
//default value of nSplitter is 5 ,_.@l+BM.  
this("","","",5); 6C:x6'5[  
} kf+JM/  
JdaFY+f:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $xRo<,OV+  
{ zQL!(2  
sSiteURL= sURL; `"xk,fVYd  
sFilePath = sPath; \3t,|%v  
sFileName = sName; :kWZSN8.D  
this.nSplitter = nSpiltter; Wk/fB0  
Jj=yG"$!  
V~'k1P4  
} Y)'!'J  
b(q$j/~ zb  
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public String getSSiteURL() n!UMU^  
{ 8`:M\*  
return sSiteURL; YHETI~'j.  
} "2ZIoa!^  
u{g]gA8s  
?JuX~{{.L  
public void setSSiteURL(String value) ~8jThi U  
{ KH>Sc3p  
sSiteURL = value; `xISkW4%  
} 2-8YSHlh  
.HyjL5r-  
}Q`/K;yq  
public String getSFilePath() pGY [f@_x-  
{ Y[f,ia  
return sFilePath; b%3Q$wIJ6  
} W:`5nj]H9  
6b%`^B\  
l*QIoRYFW  
public void setSFilePath(String value)  AGh~8[  
{ P7}t lHX  
sFilePath = value; 5+y@ ]5&g  
} 8BHL  
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,"@w>WL<9  
public String getSFileName() Vn)%C_-]A  
{ i%xI9BO9  
return sFileName; MPjr_yc]  
} hA@zoIoe  
])N|[|$  
lN);~|IOv7  
public void setSFileName(String value) PASuf.U$"  
{ H!Wis3S3G  
sFileName = value; nA>*IU[  
} j'k8^*M6  
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f8^"E $"  
public int getNSplitter() (})]H:W7  
{ dj3|f{kg{  
return nSplitter; &K06}[J  
} +*n]tlk  
USE   
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public void setNSplitter(int nCount) *]Fg
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{ 'n>K^rA  
nSplitter = nCount; $X`bm*  
} Pg7>ce  
} e%pu.q\gK  
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IZ+*`E  
/* SrSG{/{  
**Utility.java s;s0}Td_1  
*/  NI^{$QMj  
package NetFox; b([:,T7  
]F*|U`  
I9;xzES  
public class Utility { >g=^,G}y  
TKK,Y{{  
1d`cTaQ-  
public Utility() Ny[QT*nV  
{ (viWY  
=ntftSH  
j(&GVy^;?  
} HB%K|&!+  
uG4$2  
//线程睡眠 bdCykG-  
public static void sleep(int nSecond) x,w8r+~5  
{ yXkt:O,i  
try{ _0w1kqW  
Thread.sleep(nSecond); `q^(SM  
} %yeu"  
catch(Exception e) { AFf:[G  
{ 'CgV0&@  
e.printStackTrace (); >xZ5ac I  
} |0lLl^zp  
} kPWBDpzN  
:RHm*vt  
//日志 p*Xix%#6  
public static void log(String sMsg) K6-6
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{ FzVZs#O  
System.err.println(sMsg); lBS"3s384  
} jg?bf/$s  
 %W(^6p!  
nkTYWw  
public static void log(int sMsg) )u<eO FI+  
{ C B6A}m  
System.err.println(sMsg); vlvvi()  
} Cb4_ ?OR0  
} ka/nQ~_#<  
[8.-(-/;  
I4ebkPgf  
/* Mw+v"l&mU  
**TestMethod.java _FT6]I0  
*/ >d#3|;RY  
package NetFox; pKq]X}[^c  
axtb<5&  
0',[J  
public class TestMethod { GKCM|Y  
Vn^)  
Z4#v~!  
public TestMethod() S.1(3j*  
{ ///xx/weblogic60b2_win.exe 7H4L-J3  
try{ Y|_O8[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]Y{,Nx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~JLYhA^'+<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #,TELzUVE  
fileFetch.start(); 76_<xUt{  
} N\'TR6_,b  
catch(Exception e){e.printStackTrace ();} Yc|uD-y  
7_KXD#  
*U_S1>0n  
} (#If1[L  
pcnl0o~  
oXdel Ju?  
public static void main(String[] args) =MxpH+spI  
{ j|mv+O  
new TestMethod(); $2QYxY9s  
} cW; H!:&  
} 9)Ly}Kzx  
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