http断点续传简单实现（java)

/* ee%fqVQ8P  
**SiteFileFetch.java MZ Aij  
*/
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package NetFox; 0#w?HCx=  
import java.io.*; }cT_qqw(f%  
import java.net.*; ,0x y\u  
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public class SiteFileFetch extends Thread { H*#s }9=kZ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean q_-7i  
long[] nStartPos; //开始位置 Q+g!V5'  
long[] nEndPos; //结束位置 b Q]/?cCYV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 LPMU8Er  
long nFileLength; //文件长度 :0s]U_
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boolean bFirst = true; //是否第一次取文件 x|yEtO&  
boolean bStop = false; //停止标志 .e=C{  
File tmpFile; //文件下载的临时信息 A.hd Kl  
DataOutputStream output; //输出到文件的输出流 Yjx|9_|Xn  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &u#&@J  
public SiteFileFetch(SiteInfoBean bean) throws IOException pdE3r$C  
{ ?LvCR_D:  
siteInfoBean = bean; C@th O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); xg)v0y~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); E<y
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if(tmpFile.exists ()) p.LFVFPT  
{ cA%%IL$R  
bFirst = false; ]`Oo%$Ue  
read_nPos(); rn<PR*  
} #1>X58I^  
else r*Yi1j/  
{ }Ho Qwy|&  
nStartPos = new long[bean.getNSplitter()]; ^^5&QSB:'  
nEndPos = new long[bean.getNSplitter()]; 8Y5  
} **}h&k&%2  
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) $PDo 7#  
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} `w]s
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public void run() 7)s^8+  
{ "~D]E7Q3y  
//获得文件长度 r$2P;Cxj  
//分割文件 AhZ8 0!  
//实例FileSplitterFetch N!g9*Z
 
//启动FileSplitterFetch线程 Mbb x`  
//等待子线程返回 Nm|!#(L  
try{ o7|eMe?<t  
if(bFirst) ]xuG&O"SBV  
{ 0qX3v<+[6  
nFileLength = getFileSize(); Th=eNL]  
if(nFileLength == -1) OF\rgz
 
{ L'u\w  
System.err.println("File Length is not known!"); 2Lx3=k  
} =jN*P?  
else if(nFileLength == -2) }Hn/I,/  
{ k{'0[,mx#  
System.err.println("File is not access!"); ^MVkZ{gtre  
} 9/nn)soC3  
else 0:+WO%z  
{ {?yr'*  
for(int i=0;i<nStartPos.length;i++) Hla0 5N' 4  
{ s0PrbL%_`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^Vpq$'!  
} i9/aAH
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for(int i=0;i<nEndPos.length-1;i++) nw-I|PVTNa  
{ ]C) 4  
nEndPos = nStartPos[i+1]; ?mwD*LN3o  
} 92EWIHEWZ  
nEndPos[nEndPos.length-1] = nFileLength; Z?\2F%  
} p\bDY  
} ~$~5qwl  
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//启动子线程 }K&7%N4LZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; e
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for(int i=0;i<nStartPos.length;i++) ]w.;4`l*  
{ lBaR  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [D!jv"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XHK70: i  
nStartPos,nEndPos,i); ^/r7@:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m@^1JlH  
fileSplitterFetch.start(); DCZ\6WY1G)  
} yxH ( c  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?Orxmxc 2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]wtb-PC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", QDu2?EYZq  
nEndPos = " + nFileLength); <WcR,d  
// fileSplitterFetch[nPos.length-1].start(); U-|N
Y
  
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>k'c'7/  
//等待子线程结束 jrS[f  
//int count = 0; l g-X:Z.  
//是否结束while循环 {DR`;ea])1  
boolean breakWhile = false; ndkti5L,   
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9T1Z
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while(!bStop) u,UmrR  
{ |]c8jG\h  
write_nPos(); 49vcoHlf  
Utility.sleep(500); Qc pm!  
breakWhile = true; IyPwP*A  
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for(int i=0;i<nStartPos.length;i++) O)jWZOVp >  
{ T87m?a$  
if(!fileSplitterFetch.bDownOver) gntxNp[9T  
{ g4l
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breakWhile = false; /bi}'H+#  
break; I= &stsH  
} .dav8n*  
} RS^lKJ1 U  
if(breakWhile) L>3x9  
break; eN^qG 42  
43@{JK9G  
;S>])
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//count++; (Kv#m 3~  
//if(count>4) m8o(J\]  
// siteStop(); 7eiV{tYF  
} %;rHrDP(>  
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System.err.println("文件下载结束！"); WUh$^5W  
} !s&NT @ S  
catch(Exception e){e.printStackTrace ();} yI"6Da6|y  
} !Y[lQXv  
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//获得文件长度 1 =M ?GDc  
public long getFileSize() 7BJzMlJ1Y  
{ BYMi6wts  
int nFileLength = -1; o<|P9#(U"  
try{ < Pky9o;  
URL url = new URL(siteInfoBean.getSSiteURL()); MZT23[+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6Q${U7%7  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;u>DNG|.  
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int responseCode=httpConnection.getResponseCode(); 1fZ(l"  
if(responseCode>=400) u)~C;f)  
{  7*?}:  
processErrorCode(responseCode); E<Q f!2s$  
return -2; //-2 represent access is error RH&~+5  
} i*@<y/&'  
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String sHeader; K5x
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for(int i=1;;i++) k@z,Iq8  
{ Yj6*NZ*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <1t*I!e_  
//Utility.log(in.readLine()); FW21 U<  
sHeader=httpConnection.getHeaderFieldKey(i); G1o3l~x  
if(sHeader!=null) #~<0t(3Q  
{ #g]vc_V  
if(sHeader.equals("Content-Length")) `0Oh_8"  
{ T>NDSami  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); j4^97  
break; .8by"?**  
} *tK\R&4,4s  
} ,f[>L|?e  
else Z)SY.iK.  
break; s]f6/x/~  
} `1bv@yzq  
} !Rhlf.x  
catch(IOException e){e.printStackTrace ();} i}B2R$Z3  
catch(Exception e){e.printStackTrace ();} >kW@~WDMu  
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Utility.log(nFileLength); }<9cL'  
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return nFileLength; V;,{}  
} qLB)XnQ  
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//保存下载信息（文件指针位置） B>0].CK`  
private void write_nPos() V{:A3C41  
{ USM4r!x  
try{ xUa{1!Y8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YLiSbLz1  
output.writeInt(nStartPos.length); M!REygyx  
for(int i=0;i<nStartPos.length;i++) F!]lU`z)=  
{ 7~5ym15*  
// output.writeLong(nPos); ?B}{GL2)  
output.writeLong(fileSplitterFetch.nStartPos); $h*L=t(  
output.writeLong(fileSplitterFetch.nEndPos); 8n*.).33  
} &L,nqc\3D5  
output.close(); O8j_0  
} K otrX  
catch(IOException e){e.printStackTrace ();} N<IT w/@^  
catch(Exception e){e.printStackTrace ();} $Z\.-QE\  
} J 
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//读取保存的下载信息（文件指针位置） 2C9V|[U,  
private void read_nPos() br":y>=,  
{ {;:/-0s  
try{ IHcD*zQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xT+
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int nCount = input.readInt(); B#.L  
nStartPos = new long[nCount]; b"#WxgaF  
nEndPos = new long[nCount]; Y}#J4i0b*  
for(int i=0;i<nStartPos.length;i++) d;>#Sxf  
{ ,^eYlmT>6
 
nStartPos = input.readLong(); \ywXi~+kUv  
nEndPos = input.readLong(); :[hgxJu+  
} |~X ;1j!  
input.close(); S|]X'f  
} b-{=s+:  
catch(IOException e){e.printStackTrace ();} (4dhuT  
catch(Exception e){e.printStackTrace ();} K0}pi+=  
} cM$P`{QrM  
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private void processErrorCode(int nErrorCode) RIY,K*f.  
{ enSXP~9w  
System.err.println("Error Code : " + nErrorCode); 8(~K~q[Cr  
} zhpt%7So  
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XbD4:i%  
//停止文件下载 ^7 &5 z&o  
public void siteStop() Ipq"E  
{ ~s
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bStop = true; 8p@Piy{p  
for(int i=0;i<nStartPos.length;i++) [g:$K5\64  
fileSplitterFetch.splitterStop(); /M3Y~l$  
/qy-qUh3h  
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} /.o^R6  
} .2v_H5<  
//负责部分文件的抓取 *U]V@;XF  
**FileSplitterFetch.java e0T34x'
  
*/ vfE6Ggz  
package NetFox; ysQ,)QoiR{  
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import java.io.*; oIb|*gX^  
import java.net.*; Vc2A  
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public class FileSplitterFetch extends Thread { LS88.w\=S@  
Zy(W^~NT  
8$;=Uf,x  
String sURL; //File URL ]2\VweV  
long nStartPos; //File Snippet Start Position _PlKhv}  
long nEndPos; //File Snippet End Position )Ccq4i  
int nThreadID; //Thread's ID pXtXjb  
boolean bDownOver = false; //Downing is over w &(|e <  
boolean bStop = false; //Stop identical f=mZu1(FZ  
FileAccessI fileAccessI = null; //File Access interface 2|}+T6_q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6T#+V37  
{ \3S8 62B7  
this.sURL = sURL;  lS'-xEv?  
this.nStartPos = nStart; ` M3w]qJ<}  
this.nEndPos = nEnd; zN:K%AiGxe  
nThreadID = id; t`,`6
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 aW
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} <\pfIJr$  
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public void run() #~l(]h@ )  
{ pt?q#EfFJ  
while(nStartPos < nEndPos && !bStop) kAC&S!n  
{ (r D_(%o  
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try{ %]8qAtV^3j  
URL url = new URL(sURL); NwG= <U*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,H19`;Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); G6FEp`  
String sProperty = "bytes="+nStartPos+"-"; Dqe^E%mc  
httpConnection.setRequestProperty("RANGE",sProperty); nY`RRC  
Utility.log(sProperty); 2VJR$Pao  
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InputStream input = httpConnection.getInputStream(); y10h#&k  
//logResponseHead(httpConnection); DFd%9*N  
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byte[] b = new byte[1024]; Hqn#yInA7~  
int nRead; \,7}mdQSv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Tny%7xSx1  
{ 2U:H545]]  
nStartPos += fileAccessI.write(b,0,nRead); p-/|mL  
//if(nThreadID == 1) lAJxr8 .  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (3#Cl 1]f  
} 0#S W!b|%  
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Utility.log("Thread " + nThreadID + " is over!"); `P3>S(Tgy  
bDownOver = true; ],J
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//nPos = fileAccessI.write (b,0,nRead);
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} /i-J&*6_  
catch(Exception e){e.printStackTrace ();} JZD[NZ<  
} =<X?sj5  
} .NvQm]N0.  
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de;GrPLAi  
//打印回应的头信息 846$x$G4  
public void logResponseHead(HttpURLConnection con) +{W>i;U  
{ 3rc
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for(int i=1;;i++) X90J!  
{ r.>].~}4  
String header=con.getHeaderFieldKey(i); Z<SLc,]^  
if(header!=null) JA'h4AXk  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %JHGiCv|  
Utility.log(header+" : "+con.getHeaderField(header)); R%qGPO5Z\c  
else d\61;C  
break; },>pDeX^P  
} Qkd<sxL  
} qLT>Mz)$%  
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public void splitterStop() bV$)!]V  
{ G1"zElug  
bStop = true; 0DmMG  
} OVko+X`  
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} =|%Cu&  
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/* -"h;uDz|z  
**FileAccess.java !\"5rNy  
*//文件访问(定位，写) 4x;/HEb7?  
package NetFox; HaYE9/xS  
import java.io.*; 2#<xAR  
%d>=+Ds[  
,Td!|~I|j6  
public class FileAccessI implements Serializable{ 'eJ+JM<0%
 
bD[!/'4eJ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c=L2%XPP  
RandomAccessFile oSavedFile; Jnna$6G)B  
long nPos; L\&<sy"H  
Sk:ws&D1u  
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public FileAccessI() throws IOException NyVnA  
{ y
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this("",0); ae*Mf7  
} z[cyA.  
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public FileAccessI(String sName,long nPos) throws IOException \z$p%4`E@  
{ &Ibu>di4[  
oSavedFile = new RandomAccessFile(sName,"rw"); (A?H1 9  
this.nPos = nPos; |kvC H<F'  
oSavedFile.seek(nPos); 1e>s{  
} =7C%P%yt  
Qum9A  
:L1dyVA{  
public synchronized int write(byte[] b,int nStart,int nLen) HVP"A3}KC  
{ BvR-K\rx  
int n = -1; 9

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try{ /qx0TDB  
oSavedFile.write(b,nStart,nLen); 8 XICF  
n = nLen; zD(`B+  
} H~+l7OhV  
catch(IOException e) awOd_![c'  
{ mFSw@CC  
e.printStackTrace (); H]$)Eg%6  
} lNL6M%e$Q  
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;Ww7"-=sw  
return n; FRS>KO=3  
} {2+L@  
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} XP1~d>j  
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QR Ei7@t  
/* 5Pd"h S  
**SiteInfoBean.java .9"Y_/0   
*/ Ty<L8+B|  
package NetFox;
AN24Sf'`  
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xw3YK!$sIF  
public class SiteInfoBean { 6X\ 2GC9  
7\9>a  
{qmdm`V[  
private String sSiteURL; //Site's URL o.'g]Q<}UB  
private String sFilePath; //Saved File's Path TP"1\O  
private String sFileName; //Saved File's Name %^8^yZz  
private int nSplitter; //Count of Splited Downloading File RtCkVxaEx  
5e}A@GyC  
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public SiteInfoBean() ]Lm9^q14m  
{//nSplitter的缺省值为5 7yx$Nn`(  
//default value of nSplitter is 5 lr{?"tl_  
this("","","",5); u_'!_T L  
} ,N e;kI  
^RP)>d9Xp{  
DZv=\<$,LF  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [ e8x&{L-_  
{ |<Gl91  
sSiteURL= sURL; ]ZoD'-,  
sFilePath = sPath; `d[1`P1i[  
sFileName = sName; *JaqTI,e  
this.nSplitter = nSpiltter; Qhw^S*  
.-IkL|M  
}4{fQ`HT  
} l6~-8d+lfN  
b L]erYm  
1I*7SkgKv  
public String getSSiteURL() z9p05NFH  
{ 3 HIz9F(  
return sSiteURL; Rt{B(L.?<  
} oh KCdT~  
&E40* (C  
jC3Vbm&ZZ  
public void setSSiteURL(String value) P{5
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{ 6}(J6T46M[  
sSiteURL = value; p<&Xd}]"^W  
} @0eHS+  
4WN3=B  
dTL5-@  
public String getSFilePath() zOSs[[  
{ rC7``#5  
return sFilePath; 2<][%> '  
} F! X}(N?t  
`iJhG^w9M  
fsEzpUY:{W  
public void setSFilePath(String value) h@@nR(<i  
{ eXkujjSw"  
sFilePath = value; (__yh^h:m  
} 7;tJK^J`  
#CnHf  
nD0}wiL{  
public String getSFileName() I0'[!kBF|  
{ T /mI[*1xI  
return sFileName; \(PohwWWo  
} L3p`  
78Aa|AJU  
UDc$"a}ds{  
public void setSFileName(String value) {\z({Wlb]  
{ &%2*Wu;  
sFileName = value; 'r@:Cz3e*I  
} qU,c~C=Qf  
8:o<ry  
b:(-  
public int getNSplitter() X<MO7I  
{ 7nVRn9Hn  
return nSplitter; oM2UzB{(  
} { K_kPgKS  
x%<  
=B];?%  
public void setNSplitter(int nCount) %+F"QI1~0  
{ ~fa(=.h  
nSplitter = nCount; N6T{  
} 4_D@ST%  
} o%4G
d~
  
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/* $v`afd y  
**Utility.java O Lc}_  
*/ Ka|eFprS  
package NetFox; a|BcnYN  
Ln.ZVMZ;  
@<@SMK)  
public class Utility { KT.?Xp:z  
ycJg%]F*5  
tj*y)28
-  
public Utility() /?6gdN  
{ M0' a9.d  
G
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} EQe5JFR  
E"|4Y(G  
//线程睡眠 $2MAZGJV
 
public static void sleep(int nSecond) aZk&`Jpz  
{ Dw2Q 'E  
try{ npD
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Thread.sleep(nSecond); zD)pF1,7:8  
} DOQc"+  
catch(Exception e) !>(RK"KWq]  
{ #u5~0,F  
e.printStackTrace (); a1.|X i'/z  
} 8CC/BOe  
} oW$s xS  
u=&Bmn_  
//日志 -z:&*=  
public static void log(String sMsg) Kv{8iAB#c  
{ }4>JO""  
System.err.println(sMsg); WV"jH9"[  
} _ OaRY]  
}#v{`Sn%^C  
,&YTj>  
public static void log(int sMsg) Zw] ?.  
{ XTeb9h)3  
System.err.println(sMsg); CodSJ,  
} ;50_0Mv;(:  
} .5Q:Xp  
*zWWmxcJa  
4.K'
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/* U
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**TestMethod.java >J=<bhR  
*/ 1# t6`N]?V  
package NetFox; L fl-!1  
?`zgq>R}w[  
quo^fqS&a  
public class TestMethod { 6`$[Ini  
*]x*B@RF  
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public TestMethod() ~SjZk|  
{ ///xx/weblogic60b2_win.exe nMoWOP'  
try{ pGIe=Um0W  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [rreFSy#@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }Uf<ZXW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); uD["{?H  
fileFetch.start(); *o' 4,+=am  
} ecX/K.8l  
catch(Exception e){e.printStackTrace ();} !]S=z^"<  
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l SkEuN  
} x7RdZC  
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public static void main(String[] args) QMk+RM8U  
{ yu ,h\  
new TestMethod(); &!y]:CC{  
} kDB iBNdB  
} m]IysyFFK  
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