http断点续传简单实现（java)

/* HU}7zK2  
**SiteFileFetch.java '!cCMTj  
*/ eKLZt%=  
package NetFox; UA0Bzoky;  
import java.io.*; 2K6qY)/_  
import java.net.*; Yty/3T3)e  
4 Y9`IgQ  
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public class SiteFileFetch extends Thread { UWJ8amA  
B=T'5&  
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SiteInfoBean siteInfoBean = null; //文件信息Bean gNrjo=  
long[] nStartPos; //开始位置 $}q23  
long[] nEndPos; //结束位置 T|op$ s|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 T_ <@..C  
long nFileLength; //文件长度 l^-];|Y  
boolean bFirst = true; //是否第一次取文件 oUr66a/[U  
boolean bStop = false; //停止标志 v2\FA(BPn  
File tmpFile; //文件下载的临时信息 kGS;sB  
DataOutputStream output; //输出到文件的输出流 &|ex`nwc0  
T#Z^s~7&I  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） w"|L:8  
public SiteFileFetch(SiteInfoBean bean) throws IOException k[YS8g-Q  
{ 8.=BaNU  
siteInfoBean = bean; S-b/S5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <CiSK!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1~`fVg  
if(tmpFile.exists ()) @6sqMw}  
{ 9c'xHO`  
bFirst = false; b<ZIWfs  
read_nPos(); OU.6bmWy|  
} Tc:)- z[o  
else mh#a#<  
{ mb3"U"ohs  
nStartPos = new long[bean.getNSplitter()]; |O+H[;TB6  
nEndPos = new long[bean.getNSplitter()]; v^NIx q}U  
} F6|]4H.3Q  
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} D%SlAzZ3  
0<@KG8@hI;  
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public void run()  `25yE/  
{ MrFQ5:=  
//获得文件长度 3M7/?TMw{6  
//分割文件 >Q;l(fdj  
//实例FileSplitterFetch W,n!3:7s  
//启动FileSplitterFetch线程 #A/  
//等待子线程返回 8MtGlW%Eh  
try{ HM1Fz\Sf  
if(bFirst) ~jk|4`I?T  
{ m?}6)\ob  
nFileLength = getFileSize(); o#Dk& cH  
if(nFileLength == -1) 4.aZ#c91_  
{ +GN(Ug'R  
System.err.println("File Length is not known!"); s^9Voi.y  
} F~W6Bp^W  
else if(nFileLength == -2) 1n8/r}q'H  
{ b. '-?Nn  
System.err.println("File is not access!"); &PHTpkaam  
} ksUcx4;a@F  
else ,w4(kcg%iQ  
{ yx[/|nZDC4  
for(int i=0;i<nStartPos.length;i++) 8kIks
y  
{ ec;o\erPG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~,Ix0h+H+M  
} ^uc=f2=>,  
for(int i=0;i<nEndPos.length-1;i++)  |>^JRx  
{ \*?~Yj#  
nEndPos = nStartPos[i+1]; [|$h*YK  
} Q3~H{)[Kq  
nEndPos[nEndPos.length-1] = nFileLength; N>`Aw^ _@&  
} ;H*T^0  
} K5h  
|wMN}bq|T  
(%6P0*  
//启动子线程 ="H`V V_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t3_O H^  
for(int i=0;i<nStartPos.length;i++) !;A\.~-!G  
{ T7%S #0,p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H*R"ntI?w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]_gU#,8  
nStartPos,nEndPos,i); uGGt\.$]s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .`eN8Dl1  
fileSplitterFetch.start(); Rhs/3O8k  
} + &Eqk  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +O{*M9B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); LEdh!</'24  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Yj49
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nEndPos = " + nFileLength); rM%1GPVob  
// fileSplitterFetch[nPos.length-1].start(); (L&d!$,Dv  
"KpGlY?^  
=dKtV.L  
//等待子线程结束 va@Lz&sAE%  
//int count = 0; $UWZDD  
//是否结束while循环 gwMNYMI  
boolean breakWhile = false; ?fSG'\h>  
d#FQc18v}k  
a1lh-2xX  
while(!bStop) lymCH  
{ g) jYFfGfH  
write_nPos(); ^09,"<@k  
Utility.sleep(500); 99QU3c<.  
breakWhile = true; TvbE2Q;/UL  
rV#ch(  
)y$(AJx$  
for(int i=0;i<nStartPos.length;i++) ;.980+i1  
{ li.;IWb0+)  
if(!fileSplitterFetch.bDownOver) sO@Tf\d  
{ g($2Dk_F2  
breakWhile = false; O\r0bUPE  
break; sXPe/fWo  
} .ioEIsg  
} |CyE5i0  
if(breakWhile) c^W)07-X5y  
break; j\M?~=*w  
%.|@]!C  
Gd85kY@w7  
//count++; bk[!8-b/a  
//if(count>4) ym1Y4,  
// siteStop(); \9T7A&  
} 6'f;-2  
SmO~,2=  
0g8NHkM:2a  
System.err.println("文件下载结束！"); %pCT
N P  
} +ZP7{%  
catch(Exception e){e.printStackTrace ();} eHUOU>&P]  
} (tW`=]z-<  
!4+<<(B=E  
dR]m8mdqc1  
//获得文件长度 OjA,]Gv6  
public long getFileSize() V0mn4sfs  
{ C3g_!dUs  
int nFileLength = -1; )^hbsMhO  
try{ hhvyf^o  
URL url = new URL(siteInfoBean.getSSiteURL()); C0Z=~Q%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v3>UV8c'  
httpConnection.setRequestProperty("User-Agent","NetFox"); :ShT|n7  
8&dF  

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int responseCode=httpConnection.getResponseCode(); owv[M6lbD  
if(responseCode>=400) F!K>Kz  
{ &K,i f  
processErrorCode(responseCode); Vxt+]5X  
return -2; //-2 represent access is error uB?ZcF}Tk  
} )+Pus~w  
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4  
$ocdI
5  
String sHeader; #g!.T g'  
/>>\IR  
`Q,H|hp;k;  
for(int i=1;;i++) q5S9C%b  
{ aw>#P   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %&bY]w  
//Utility.log(in.readLine()); d/@,@8:  
sHeader=httpConnection.getHeaderFieldKey(i); sDV Q#}a  
if(sHeader!=null) hE-M$LmN@  
{ 7 X4LJf  
if(sHeader.equals("Content-Length")) 1h5 Akq  
{ apxph2yvS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); e96k{C`j0  
break; ^<AwG=  
} }ad|g6i
`  
} (7*}-Uy[C  
else v &+R^iLE  
break; $ME)#(  
} /a o5FL  
} ~Cjn7  
catch(IOException e){e.printStackTrace ();} {(}By/_  
catch(Exception e){e.printStackTrace ();} u#SWj,X  
?bu>r=oIO]  
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Utility.log(nFileLength); ct}9i"H#1  
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{VoHh_[5%  
return nFileLength; Y nZiTe@  
} `9.r`&T6K  
ReeH@.74  
_J[P[(ab  
//保存下载信息（文件指针位置） po7qmLq  
private void write_nPos() cCc(fF*^  
{ FxtI"g\0  
try{ 5/z/>D;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !{41!O,K#  
output.writeInt(nStartPos.length); t&DEb_"De  
for(int i=0;i<nStartPos.length;i++) &jr3B;g!C  
{ -|\ZrE_h  
// output.writeLong(nPos); ;jTN| i'  
output.writeLong(fileSplitterFetch.nStartPos); Ecx
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output.writeLong(fileSplitterFetch.nEndPos); {FTqu.  
} HUOj0T  
output.close(); C{wEzM:  
} p
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catch(IOException e){e.printStackTrace ();} n{SJ_S#a.a  
catch(Exception e){e.printStackTrace ();} [PKR2UEe]  
} 2dgd~   
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//读取保存的下载信息（文件指针位置） Pr,q*_Yy  
private void read_nPos() W+1^4::+  
{ R_xRp&5  
try{ XBw)H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Vs{|xG7WD  
int nCount = input.readInt(); %;"y+YFdv  
nStartPos = new long[nCount]; Oz#{S:24M+  
nEndPos = new long[nCount]; o,3a4nH;  
for(int i=0;i<nStartPos.length;i++) sFTy(A/  
{ {cw /!B  
nStartPos = input.readLong(); qb` \)X]9  
nEndPos = input.readLong(); eQvg7aO;  
} rk)`\=No  
input.close(); e64^ChCoV  
} ##4HYQ%E  
catch(IOException e){e.printStackTrace ();} N$:8,9.z  
catch(Exception e){e.printStackTrace ();} -RK- Fu<e  
} @gXx1hEg  
XHGFf_kW_N  
5.J.RE"M  
private void processErrorCode(int nErrorCode) MR.'t9m2L  
{ 63x?MY6  
System.err.println("Error Code : " + nErrorCode); ;mKb]  
} ZWp(GC1NA  
>~+ELVB&  
8|58 H  
//停止文件下载 VTHH&$ZNq  
public void siteStop() g95`.V}  
{ U_c
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bStop = true; 2SR:FUV/  
for(int i=0;i<nStartPos.length;i++) I[X772K  
fileSplitterFetch.splitterStop(); 3%=~)7cF  
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8BNi1Qn$  
} K@w{"7}  
} m/EFHS49  
//负责部分文件的抓取 0%I=d  
**FileSplitterFetch.java V,N%;iB}  
*/ 4x[S\,20  
package NetFox; ~gRf:VXX=_  
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@bP)406p  
import java.io.*; 2WYPO"q  
import java.net.*; ~z;FP$U  
C'}KTXiRW
 
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public class FileSplitterFetch extends Thread { "AGLVp.zT  
*<ewS8f*6  
Al
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String sURL; //File URL cDH^\-z  
long nStartPos; //File Snippet Start Position l0A&9g*l2  
long nEndPos; //File Snippet End Position 2x0<&Xy#P  
int nThreadID; //Thread's ID <B8!.|19  
boolean bDownOver = false; //Downing is over 1c{DY  
boolean bStop = false; //Stop identical OX\F~+  
FileAccessI fileAccessI = null; //File Access interface dL )<% o  
b(O3@Q6[  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException V[vl!XM  
{ 8StgsM  
this.sURL = sURL; N7R!C)!IL  
this.nStartPos = nStart; ChXq4]  
this.nEndPos = nEnd; >[=^_8M  
nThreadID = id; 9|CN8x-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )gy!GK  
} PdtvU-(  
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public void run() |64~K\X  
{ **G9H  
while(nStartPos < nEndPos && !bStop) F;0}x;:>  
{ aM0f/"-_  
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>%8KK|V{  
try{ qVwIo.g!  
URL url = new URL(sURL); 3]3|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ..'_o~Ka  
httpConnection.setRequestProperty("User-Agent","NetFox"); ':m,)G5&  
String sProperty = "bytes="+nStartPos+"-"; FZE"7ec>m  
httpConnection.setRequestProperty("RANGE",sProperty); Y,t={HiclX  
Utility.log(sProperty); gi _5?$  
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V~;1IQd{  
InputStream input = httpConnection.getInputStream();
*U=s\  
//logResponseHead(httpConnection); k4y'b  
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byte[] b = new byte[1024]; 6-B|Y3)B  
int nRead; d;9FB[MmOJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R)ITy!z  
{ t+T4-1 3a  
nStartPos += fileAccessI.write(b,0,nRead); /9pwZ%:<  
//if(nThreadID == 1) Ob`d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JKmIvZ)8  
} q0r>2c-d  
)6,=f.%  
mahJSz(3  
Utility.log("Thread " + nThreadID + " is over!"); 9=h'9Wo  
bDownOver = true; @Y<bwv  
//nPos = fileAccessI.write (b,0,nRead); A='N=^Pm  
} !SdSE^lz`  
catch(Exception e){e.printStackTrace ();} @? QoF#D  
} 9}F*P669f  
} .NC:;@y  

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fnX`Q[b4\A  
//打印回应的头信息 .ndC
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public void logResponseHead(HttpURLConnection con) .|b$NM  
{ *>2W#D)b=  
for(int i=1;;i++) +:!7L=N#  
{ ]cZ!y ~  
String header=con.getHeaderFieldKey(i); F{~{Lthc  
if(header!=null) Xi,CV[L\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %Iv,@}kvT+  
Utility.log(header+" : "+con.getHeaderField(header)); BB*f
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else ;=; 9tX  
break; vyX\'r.~7  
} SVs_dG$  
} 7k9G(i[-+  
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 s ;oQS5Y  
public void splitterStop() Y^7
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{ $oU*9}}Rn  
bStop = true; vV6I0  
} _%!c+f7  
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} XJ` ]ga  
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9~mh@Kgv  
/* Q$1bWUS&  
**FileAccess.java ?:8ido#-  
*//文件访问(定位，写) y7 3VFb  
package NetFox; uRRQy
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import java.io.*; V#t%/l  
)
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9N<<{rQ,F  
public class FileAccessI implements Serializable{ 1[qLA!
+  
o( RG-$  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =K{"{5Wb  
RandomAccessFile oSavedFile; L,`Lggq-  
long nPos; qnJt5  
FsV'Cu@!U  
36
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public FileAccessI() throws IOException &7b|4a8B%  
{ 6c"0})p  
this("",0); 28H8l2{[>  
} $8xl#SqH  
*4xat:@{{  
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public FileAccessI(String sName,long nPos) throws IOException &8>IeK{I  
{ YN2sdG  
oSavedFile = new RandomAccessFile(sName,"rw"); KgOqbSJ  
this.nPos = nPos; W?aI|U1  
oSavedFile.seek(nPos); Xr2ou5zAn  
} 4.h=&jz&  
, GY h9  
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public synchronized int write(byte[] b,int nStart,int nLen) |8=nL$u  
{ fX.>9H[w@~  
int n = -1; 2viM)+  
try{ {Jx4xpvPo  
oSavedFile.write(b,nStart,nLen); x2z;6)  
n = nLen; kc @[9eV  
} W#BM(I  
catch(IOException e) Y$Y_fjd_  
{ {%{`l-  
e.printStackTrace (); CkD#/  
} }!/$M\w  
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return n; .I'o  
} 92d6U2T4&  
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} UkHY[M7;  
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/* &jczO-R^  
**SiteInfoBean.java C,NxE5?h  
*/ J.dLPKU;-  
package NetFox; d/|D<Sb[s  
;VNMD 6H  
4e;yG>  
public class SiteInfoBean { 'GoZqiYT  
MR,R}B$  
HJ[/|NZU$  
private String sSiteURL; //Site's URL Cc<,z*T  
private String sFilePath; //Saved File's Path T<@cd|`  
private String sFileName; //Saved File's Name M=*bh5t%]  
private int nSplitter; //Count of Splited Downloading File |'+eMl  
RJH,  
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public SiteInfoBean() xD /9F18  
{//nSplitter的缺省值为5 !>`N$-U X  
//default value of nSplitter is 5 |*Yf.-  
this("","","",5); ND,Kldji  
} uy^   
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Q
33"u/-v  
{ ;k86"W  
sSiteURL= sURL; qdG~!h7j  
sFilePath = sPath; Za7q$7F7Bc  
sFileName = sName; kWb2F7m  
this.nSplitter = nSpiltter; |R@~-Ht  
8W+gl=C~  
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} F3lw@b3])  
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9W>Y#V~|v!  
public String getSSiteURL() s(LT  
{ -MugnB6  
return sSiteURL; Rek -`ki5F  
} q$.{j"cZV  
8; R|  
<U9/InN0[  
public void setSSiteURL(String value) A[dvEb;r  
{ 1?Aga,~k:a  
sSiteURL = value; &G>(9  
} ia{c  
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edy  
>x@P|\  
public String getSFilePath() m&0"<V!H/B  
{ W*:,m8wk  
return sFilePath; Q2%QLM:.,  
} 3PUAH  
R
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public void setSFilePath(String value) w$5A|%Y+V}  
{ zggB$5  
sFilePath = value; }2r+%V&4  
} wVA|!>v  
l n}}5Q  
jSQ9.%4  
public String getSFileName() v)kEyX'K2d  
{ F{\gc|!i  
return sFileName; iG,t_??  
} 8g7,2f/ }  
68'>Zbelb  
Qc{RaMwD  
public void setSFileName(String value) w*w?S  
{ w[Ep*-yeI  
sFileName = value; I#FF*@oeM  
} z&$/EP-  
6vf\R*D|A  
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public int getNSplitter() l t]B#, '  
{ bT!($?GNdg  
return nSplitter; VzRx%j/i  
} [{<dbW\ 9  
M_D6i%b^  
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public void setNSplitter(int nCount) ;<G<1+  
{ 4DO/rtkVq  
nSplitter = nCount; Lg`J
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} g.#+z'l  
} g>7Y~_}  
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q
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/* K2/E#}/  
**Utility.java jlKGXD)Q[  
*/ 4W\,y_Qo  
package NetFox; .1*DR]^
`  
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f'dK73Xof  
public class Utility { s"0b%0?A  
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public Utility() h[ 6hM^n  
{ A@$fb}CF  
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} Q59/ex  
c%YDt`  
//线程睡眠 2A$0CUMb  
public static void sleep(int nSecond) oG_~3Kt  
{ 2Yyb#Ow  
try{ NR
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Thread.sleep(nSecond); bBE^^9G=Z  
} S+*cbA{J|  
catch(Exception e) 'rV2Bt,  
{ .wFU:y4r  
e.printStackTrace (); *=^[VV!  
} K M]Wl_z  
} ~{ .,8jE  
eECj_eH-  
//日志 wd`R4CKhP]  
public static void log(String sMsg) 7L{li-crI  
{ S.fXHtSx  
System.err.println(sMsg); E0bFx5e5fu  
} k`IrZHMw
 
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public static void log(int sMsg) RUrymkHFB  
{ 5~yb ~0
 
System.err.println(sMsg); A[Cg/ +Z  
} anZIB  
} ECdfLn*c  
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/2:Q6J  
/* v=+k"gm6  
**TestMethod.java 7dhn'TW  
*/ c20|Cx2m  
package NetFox; qi[(*bFK7  
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public class TestMethod { ?lG;,,jc,W  
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}`@?X"r  
public TestMethod() g
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{ ///xx/weblogic60b2_win.exe $pBr &,  
try{ tYI]=:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); G\IocZ3Gz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QW:Z[?39^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D1~^\)*  
fileFetch.start(); R^?PAHE7  
} v*gLNB,ZH  
catch(Exception e){e.printStackTrace ();} $@4e(Zrmo  
n=SzF(S[M  
Ty iU1,oO  
} z7$}#)Z7  
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DwC@"i.  
public static void main(String[] args) HO G=c!b  
{ A9.;>8!u  
new TestMethod(); |7Yvq%E  
} Fj48quW1\P  
} v,@E}F~-f1  
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