http断点续传简单实现（java)

/* XN?my@_HpM  
**SiteFileFetch.java i-p,x0th  
*/ hgDFhbHtd6  
package NetFox; SfrM|o  
import java.io.*; aZa1eE  
import java.net.*; X_bB6A6  
U,fPG/9  
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public class SiteFileFetch extends Thread { KjF8T7%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean `C-8zA  
long[] nStartPos; //开始位置 1;{nU.If  
long[] nEndPos; //结束位置 n+<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "WXUz  
long nFileLength; //文件长度 0Ny +NE:6M  
boolean bFirst = true; //是否第一次取文件 E&Lml?@  
boolean bStop = false; //停止标志 2\|sXC  
File tmpFile; //文件下载的临时信息 $rbr&TJ  
DataOutputStream output; //输出到文件的输出流 #u\~AO?h  
-!M>;M@  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )Wt&*WMFXl  
public SiteFileFetch(SiteInfoBean bean) throws IOException g1y@z8Z{  
{ OS>%pgv  
siteInfoBean = bean; Ic&YiATj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); At[Sk
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Hl{ul'o  
if(tmpFile.exists ()) jJ2{g> P0P  
{ |\| v%`r2  
bFirst = false;
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read_nPos(); $`vXI%|.  
} \FCPD.2s+  
else < %<nh`D  
{ d#ab"&$bv  
nStartPos = new long[bean.getNSplitter()]; w6lx
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nEndPos = new long[bean.getNSplitter()]; VtU2&  
} Z$('MQ|Ur  
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} ={
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public void run() j9/iBK\Y  
{ +I*a=qjq  
//获得文件长度 wsAb8U C_  
//分割文件 3{ea~G)[9  
//实例FileSplitterFetch ).Iifu|
ks  
//启动FileSplitterFetch线程 i`}9VaUG  
//等待子线程返回 p-!/p#  
try{ @.G;dL.f{  
if(bFirst) +OSSgY$  
{ 8LuU2Lo  
nFileLength = getFileSize(); N?A}WW#  
if(nFileLength == -1) q!h'rX=_-  
{ 1NrNTBI@  
System.err.println("File Length is not known!"); ir|L@Jj,  
} D&],.N  
else if(nFileLength == -2) `Uvc^  
{ \"5p)(  
System.err.println("File is not access!"); ^0
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} Qdc)S>gp  
else lx~C{tl2  
{ +lf`Dd3  
for(int i=0;i<nStartPos.length;i++) X@A8~kj1  
{ ybIqn0&[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); s4=EyBI  
} D_`~$QB`,  
for(int i=0;i<nEndPos.length-1;i++) RH$YM `cZ  
{ &v:[+zw  
nEndPos = nStartPos[i+1]; }`76yH
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} 4:s,e<Tc4v  
nEndPos[nEndPos.length-1] = nFileLength; 6"r _Y7%  
} 1k$5'^]^9]  
} M%$-c3x  
$$B#S'  
G) 37?A)  
//启动子线程 diK
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 19Mu}.+;  
for(int i=0;i<nStartPos.length;i++) = ^%*:iT  
{ R|*Eg,1g -  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cCG!X%9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N{a=CaYi+  
nStartPos,nEndPos,i); +7y#c20  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dTwYDV}:  
fileSplitterFetch.start(); sP>-k7K
.  
} 9!dG Xq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fUq #mkq}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )3 '8T>^<K  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Dh68=F0  
nEndPos = " + nFileLength); -x!JTx[K  
// fileSplitterFetch[nPos.length-1].start(); >52%^ ?  
;[:IC^9fv  
u!FF{~5cs  
//等待子线程结束 AU8sU?=  
//int count = 0; ~bw=;xF{3  
//是否结束while循环 yQN^F+.  
boolean breakWhile = false; b4(,ls  
M>{*PHze0  
4Q,|7@  
while(!bStop) {WTy/$ Qk  
{ g$Jlp
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write_nPos(); ZT<VDcP{  
Utility.sleep(500); (543`dqAmC  
breakWhile = true; CSBDSz  
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d@ ]N  
for(int i=0;i<nStartPos.length;i++) c^z)[  
{ \GZ|fmYn  
if(!fileSplitterFetch.bDownOver) Tsdgg?#  
{ O;0VKNn['  
breakWhile = false; :OA;vp~$x  
break; m!3D5z]n9  
} TQQh:y  
} I*n]8c  
if(breakWhile) tHr4/  
break; D/
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[_  
yqP=6   
j_z@VT}y  
//count++; 7/)0{B4U'  
//if(count>4) w
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// siteStop(); l9&L$,=  
} 4P#4RB  
uII! ?   
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System.err.println("文件下载结束！"); `$3ktQ$  
} zT93Sb  
catch(Exception e){e.printStackTrace ();} ;Nd'GA+1;(  
} v4Kf{
9q#  
tqjjn5!  
#+$PD`j  
//获得文件长度 (i1p6  
public long getFileSize() pwV~[+SS_  
{ MooxT7  
int nFileLength = -1; 1-Dw-./N  
try{ 3\cx(  
URL url = new URL(siteInfoBean.getSSiteURL()); CZ =]0zB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T# gx2Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7G0;_f{  
f+\UVq?  
 ^mN`!+  
int responseCode=httpConnection.getResponseCode(); lwIxn
1n  
if(responseCode>=400) G2b"R{i/,  
{ Bm<tCN-4  
processErrorCode(responseCode); q_[`PYT  
return -2; //-2 represent access is error s+E4AG1r  
} ubc k{
\.  
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String sHeader; 6P)DM  
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fUZCP*7>  
for(int i=1;;i++) _rz\[{)  
{ mP?}h  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); QSwT1P'U  
//Utility.log(in.readLine()); yw1Xxwc  
sHeader=httpConnection.getHeaderFieldKey(i); :)h4SD8Y  
if(sHeader!=null) P/Y)Yx_(  
{ ac1(lD  
if(sHeader.equals("Content-Length")) @q{.  
{ Nnoj6+b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c5pK%I}O  
break; ID,os_ T=  
} 0wAB;|~*62  
} <N3~X,ch  
else j
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break; /+WC6&  
} ?v'CuWS  
} 'Zqt~5=5  
catch(IOException e){e.printStackTrace ();} u#Bj#y!  
catch(Exception e){e.printStackTrace ();} B~,?Gbl+g  
[jEA|rd~}  
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Utility.log(nFileLength); "#iO{uMWb  
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return nFileLength; }r"E\~E  
} @]42.oP  
"chf\-!$  
Bgai|l  
//保存下载信息（文件指针位置） R@`xS<`L/  
private void write_nPos() KvI/!hl\  
{ !~j9Oc^  
try{ PTTUI
  
output = new DataOutputStream(new FileOutputStream(tmpFile)); auM1k]  
output.writeInt(nStartPos.length); %{me<\(  
for(int i=0;i<nStartPos.length;i++) Z+4Mo*#  
{ TPY&O{q  
// output.writeLong(nPos); f<R 3ND)  
output.writeLong(fileSplitterFetch.nStartPos); aD~S~L!  
output.writeLong(fileSplitterFetch.nEndPos); x_l8&RIB*  
} )5Cqyp~P  
output.close(); &?gcnMg$,J  
} x/0x&la  
catch(IOException e){e.printStackTrace ();} )a+bH</'  
catch(Exception e){e.printStackTrace ();} "`'+@KlE  
} kpk ^Uw%f  
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//读取保存的下载信息（文件指针位置） 8zwH^q[`r  
private void read_nPos() f,BJb+0  
{ ]HRHF'4  
try{ DvA#zX[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); P#;pQC  
int nCount = input.readInt(); kjSzuqB  
nStartPos = new long[nCount]; -7EwZRS@9  
nEndPos = new long[nCount]; 64:p 4
N  
for(int i=0;i<nStartPos.length;i++) 3@<m/%  
{ TETfRnm  
nStartPos = input.readLong(); qzk]9`i1:  
nEndPos = input.readLong(); dO-Zj#%7z8  
} dtXtZ!g2  
input.close(); s GrI%3[e"  
} %H}M[_f  
catch(IOException e){e.printStackTrace ();} 9AD0|,g  
catch(Exception e){e.printStackTrace ();} .0|_J|{  
} C?\HB#41  
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private void processErrorCode(int nErrorCode) Af^9WJ  
{ l8lJ &  
System.err.println("Error Code : " + nErrorCode); h@s i)5"  
} J,=^'K(  
+ERuZc$3,  
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//停止文件下载 #EH\Q%  
public void siteStop() M@0S*[O{"  
{ 0BOL0<Wq  
bStop = true; frWY8&W^H  
for(int i=0;i<nStartPos.length;i++) uLN.b339  
fileSplitterFetch.splitterStop();  yT(86#st  
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} X0KUnxw  
} mn\GLR.  
//负责部分文件的抓取 gER(&L4[  
**FileSplitterFetch.java d-]!aFj|U  
*/
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package NetFox; H#bu3*'  
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import java.io.*; |@)jS
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import java.net.*; n$"BF\eM  
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public class FileSplitterFetch extends Thread { 1_LGlu~&  
jgw+c3^R_  
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String sURL; //File URL X|60W  
long nStartPos; //File Snippet Start Position \(1WLP$2U  
long nEndPos; //File Snippet End Position M5]$w]Ny9  
int nThreadID; //Thread's ID [wUJ~~2#  
boolean bDownOver = false; //Downing is over P;e@<O  
boolean bStop = false; //Stop identical *@&V=l  
FileAccessI fileAccessI = null; //File Access interface &)EL%o5  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException FsfP^a  
{ 46c0;E\9  
this.sURL = sURL; %#7^b=;=  
this.nStartPos = nStart; p2m`pT  
this.nEndPos = nEnd; _[J>GfQd  
nThreadID = id; 0"`|f0}c  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <9?`zo$y  
} QWK\6  
}h\]0'S~J~  
4&E&{<;  
public void run() p,#**g:  
{ 2iWxx:e  
while(nStartPos < nEndPos && !bStop) g0RfvR  
{ Il<ez
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try{ 4)d#dy::\  
URL url = new URL(sURL); .A<n2-
  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ':T6m=yv  
httpConnection.setRequestProperty("User-Agent","NetFox"); TfFH!1^+  
String sProperty = "bytes="+nStartPos+"-"; %>:d5"&Lbs  
httpConnection.setRequestProperty("RANGE",sProperty); 9 N@N U:M+  
Utility.log(sProperty); k#/%#rQM  
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InputStream input = httpConnection.getInputStream(); \H.1I=<  
//logResponseHead(httpConnection); c(!{_+q"  
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byte[] b = new byte[1024]; Qx[ nR/  
int nRead; C.{z+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) n0=[N'Tw3  
{ >)iCKx
 
nStartPos += fileAccessI.write(b,0,nRead); Dad*6;+N  
//if(nThreadID == 1) [moz{Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ILXVyU  
} GvD{I;  
1;y?!;FD  
OW8"7*irT  
Utility.log("Thread " + nThreadID + " is over!"); ?rv5Z^D'  
bDownOver = true; 9vz"rHV  
//nPos = fileAccessI.write (b,0,nRead); ~ny4Ay$#  
} %!Ak]|[7  
catch(Exception e){e.printStackTrace ();} P 4jg]g  
} +J%9%DqF  
} =Ev*Q[  
 Q ,)}t  
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//打印回应的头信息 wr;8o*~  
public void logResponseHead(HttpURLConnection con) (8OaXif  
{ M}tr*L  
for(int i=1;;i++) JGKiVBN  
{ )]C7+{ImC  
String header=con.getHeaderFieldKey(i); 66l$}+|Zzc  
if(header!=null) 2x&mJ}o#k  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); O&u[^s/^  
Utility.log(header+" : "+con.getHeaderField(header)); Z2u5n`K  
else `l8^n0-  
break; jB!Q8#&Q  
} U.HeIJ#  
} Gdf*x<T1  
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public void splitterStop() W{2(fb  
{ S+EC!;@Xg  
bStop = true; bl;C=n  
} PI0[  
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} RvT
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*?Sp9PixP  
/* 7#BpGQJQ  
**FileAccess.java K2glkGK  
*//文件访问(定位，写) '8 ~E  
package NetFox; wv8WqYV  
import java.io.*; *VFUC:  
D d$ SQ  
x;cjl6Acm  
public class FileAccessI implements Serializable{ _f8<t=R  
od\Q<Jm}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \y9( b  
RandomAccessFile oSavedFile; @,RrAL}|  
long nPos; )(|+z'  
$DOBC@xxzT  
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public FileAccessI() throws IOException =*aun&  
{ #lM :BO  
this("",0); G:e9}  
} %hzl3>().  
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rQ^$)%uP  
public FileAccessI(String sName,long nPos) throws IOException p}j$p'D.RI  
{ n)(E 0h  
oSavedFile = new RandomAccessFile(sName,"rw"); 4{d!}R  
this.nPos = nPos; p<\yp<g  
oSavedFile.seek(nPos); u[_~ !y  
} b NB
pt}$  
V3'QA1$  
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public synchronized int write(byte[] b,int nStart,int nLen) , wT$L3  
{ 4%TY` II  
int n = -1; fCL5Et  
try{ <B*}W2\  
oSavedFile.write(b,nStart,nLen); %{*}KsS`p  
n = nLen; TlD)E  
} 9WaKsdf  
catch(IOException e) %Bo/vB'  
{ LO,G2]  
e.printStackTrace (); LB|FVNW/S  
} p-H q\DP  
).0h4oHSj  
R!i9N'gGG(  
return n; !YlyUHD  
} jj,Y:  
F
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} mJaWzR  
}];8v+M  
+j._NRXRH  
/* ,[rh7_  
**SiteInfoBean.java \lVxlc0{?  
*/ `b^eRnpR  
package NetFox; OchIEF"N  
72qbxPY13h  
3_JxpQg  
public class SiteInfoBean { E"e<9  
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Hf ]aA_:   
private String sSiteURL; //Site's URL $0C1';=^}  
private String sFilePath; //Saved File's Path 8}FZ1h2 4  
private String sFileName; //Saved File's Name beyC't  
private int nSplitter; //Count of Splited Downloading File Farcd!}  
/`YHPeXu  
#\kYGr-G)  
public SiteInfoBean() %Y"@VcN  
{//nSplitter的缺省值为5 [:geDk9O#'  
//default value of nSplitter is 5 Tti]H9g_  
this("","","",5); N'nI ^=  
} ]Ma2*E!p  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^PY*INv  
{ #WD}XOA  
sSiteURL= sURL; fHek!Jv.  
sFilePath = sPath; uUXvBA?l  
sFileName = sName; 6mr5`5~w  
this.nSplitter = nSpiltter; d^"<Tz!  
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} %UuV^C  
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public String getSSiteURL() Hf( d x\5  
{ _Y'+E  
return sSiteURL; kK2x';21  
} &u-H/CU%  
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public void setSSiteURL(String value) %/17K2g  
{ Yb8o`j+t  
sSiteURL = value; [bd fp a  
} X p4x:N  
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public String getSFilePath() './j<2|;U  
{ `a}!t=~#w  
return sFilePath; lg_X|yhL  
} 0*S2_&Q)  
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public void setSFilePath(String value) .l$'%AG:~  
{ dALJlRo"  
sFilePath = value; $gm`}3C<  
} DN)Eh
d.  
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public String getSFileName() ;h>s=D,r  
{ (P {o9  
return sFileName; V QE *B  
} 4R5+"h:  
V:*QK,  
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public void setSFileName(String value) 9V*h:[6a(  
{ ZSj^\JU  
sFileName = value; @N?A0S/  
} "71@WLlN  
,6U
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public int getNSplitter() _ F&BSu  
{ f6x}M9xS%  
return nSplitter; x{IxS?.j+  
} Z)cGe1?q  
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public void setNSplitter(int nCount) fMaUIJ:Q9  
{ ]YcM45x
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nSplitter = nCount; Ie(vTP1Cj  
} VmM?KlC  
} #8P9}WTno.  
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n gA&PU  
/* GaMiu!|,  
**Utility.java +~lZ]a7k  
*/ t(FIBf3  
package NetFox; y2
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public class Utility { Z6%Hhk[  
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public Utility() ||TKo967]  
{ <i
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]F[ V6`H  
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}  S^;D\6(r  
A;E7~qOG  
//线程睡眠 Qzbelt@Wx  
public static void sleep(int nSecond) !"{+|heU9p  
{ p3Uus''V4  
try{ 71i".1l{K  
Thread.sleep(nSecond); t>[K:[0U  
} 6|*em4  
catch(Exception e) "I.PV$Rxl  
{ M$j]VZ  
e.printStackTrace (); _<x4/".}B3  
} tkrRdCq  
} '(M8D5?N-  
/ 0Z_$Q&e  
//日志 bM`7>3 d7E  
public static void log(String sMsg) |,k,X}gP  
{ ?0HPd5=<v  
System.err.println(sMsg); 0KknsP7  
} C"w>U  
3
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public static void log(int sMsg) i}mvKV?!|1  
{ sG{hUsPa  
System.err.println(sMsg); [hU5ooB  
} VY }?Nb<&  
} ^3*k6h[(  
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/* :G?6Hl)~)  
**TestMethod.java m}Z=m8  
*/ >P*wK9|(  
package NetFox; JA'C\  
j_2-  
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public class TestMethod { f{=0-%dA  
Z
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"_Wv,CYmNr  
public TestMethod() =lIG#{`Q  
{ ///xx/weblogic60b2_win.exe r@;n \  
try{ x5/O.5>f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  )L}6to  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }r`m(z$z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &sJZSrk|  
fileFetch.start(); M7rVH\:[-  
} Ic_>[E?k  
catch(Exception e){e.printStackTrace ();} (h;4irfX  
zX+NhTTB  
[43:E*\$  
} ^F
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/DPD,bA  
+[$d9  
public static void main(String[] args) 5e^t;  
{ 0zR4Kj7EE  
new TestMethod(); Z["[^=EP  
} JY4sB8  
} H4#|f
n  
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