http断点续传简单实现（java)

/* wkb$^mU  
**SiteFileFetch.java [V}, tO|  
*/ Ng=ONh  
package NetFox; \R
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import java.io.*; 9A$m$  
import java.net.*; KZ:hKY@q  
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public class SiteFileFetch extends Thread { p,W_'?,9  
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SiteInfoBean siteInfoBean = null; //文件信息Bean >U!*y4  
long[] nStartPos; //开始位置 5M_Wj*a}7  
long[] nEndPos; //结束位置 l=m(mf?QBg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rf K8q'@  
long nFileLength; //文件长度 Ol/N}M|3
 
boolean bFirst = true; //是否第一次取文件 n"D ?I  
boolean bStop = false; //停止标志 xge7r3i  
File tmpFile; //文件下载的临时信息 #JW+~FU`  
DataOutputStream output; //输出到文件的输出流 [(mlv42"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |U'I/A  
public SiteFileFetch(SiteInfoBean bean) throws IOException *_-'/i  
{ j`>^1Q  
siteInfoBean = bean; !CY&{LEYn0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [iS$JG-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); iCQ>@P]nE  
if(tmpFile.exists ()) 8|g<X1H{M  
{ 8y2+&#$  
bFirst = false; dK9Zg,DZL  
read_nPos(); ]uh3R{a/  
} LHYLC>J  
else \2v"YVWw  
{ nv/[I,nw  
nStartPos = new long[bean.getNSplitter()]; Gh( A%x)  
nEndPos = new long[bean.getNSplitter()]; t?eH
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}  iThSt72  
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} ^TdZ*($5  
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public void run() *%FA:Y  
{ y/_XgPfWU  
//获得文件长度 j;~
%lg=)  
//分割文件 A*yi"{F
Li  
//实例FileSplitterFetch ;{Ux_JEg  
//启动FileSplitterFetch线程 Kq6jw/T  
//等待子线程返回 mI1H!  
try{ p*3; hGp6  
if(bFirst) chI.{R
j  
{ PL=^}{r  
nFileLength = getFileSize(); @C8DZ5)  
if(nFileLength == -1) HLK@xKD<  
{ _8?o'<!8?^  
System.err.println("File Length is not known!"); =r.
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} 6;b9swmh  
else if(nFileLength == -2) XP?rOOn  
{ ssQ BSbx
  
System.err.println("File is not access!"); 2\<.0  
} ps|)cW3`  
else 1R%1h9I4'  
{ ro~+j}*  
for(int i=0;i<nStartPos.length;i++) .?W5{U  
{ @z`@f"l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JK_OZ  
} ))h6~1`  
for(int i=0;i<nEndPos.length-1;i++) SX0_v_%M  
{ Q /x8 #X  
nEndPos = nStartPos[i+1]; vIGw6BJI  
} T]9\VW4  
nEndPos[nEndPos.length-1] = nFileLength; es:2M |#O  
} aptY6lGv-|  
} tOl e>]  
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%3Z/+uT@v]  
//启动子线程 }?@5W,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; e&<yX  
for(int i=0;i<nStartPos.length;i++) 0ezYdS~o  
{ {Tp2H_EG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +>f<EPGn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q9F)  
nStartPos,nEndPos,i); W&Y"K)`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VyLH"cCv  
fileSplitterFetch.start(); (=x"Y{%  
} D@ek9ARAq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )u:Q) %$t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #o`Ny4sq/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `|Z}2vo;j  
nEndPos = " + nFileLength); PXKJ^fa  
// fileSplitterFetch[nPos.length-1].start(); <cN~jv-w$  
%
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l,|%7-  
//等待子线程结束 JH,/jR  
//int count = 0; sYSLmUZ{  
//是否结束while循环 k"UO c=  
boolean breakWhile = false; l:B;zi`)oB  
L:nXWz  
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while(!bStop) OW;tT=ql  
{ $^/0<i$  
write_nPos(); z9/G4^qF  
Utility.sleep(500); BHDML.r }M  
breakWhile = true; 3Hi+Z}8  
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for(int i=0;i<nStartPos.length;i++) Ut@RGg+f8  
{ yBpk$  
if(!fileSplitterFetch.bDownOver) eU+ {*YJg  
{ "8)z=n  
breakWhile = false; f>jwN@(  
break; j V3)2C}  
} h!@,8y[B  
} E$s/]wnr[  
if(breakWhile) kh$_!BT  
break; #Il_J\#  
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//count++; lJ;J~>  
//if(count>4) EV M7Q>  
// siteStop(); NcS.49  
} w42OF7f  
b,H[I!. %  
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System.err.println("文件下载结束！"); ={2!c0s  
} nwI3|&  
catch(Exception e){e.printStackTrace ();} B:TR2G9UT  
} e0,'+;*=g  
imB#Eo4eY  
Nil}js27  
//获得文件长度 <~U4*  
public long getFileSize() gwkb!#A  
{ yY{kG2b,  
int nFileLength = -1; @r
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try{ ]w).8=I  
URL url = new URL(siteInfoBean.getSSiteURL()); <z+:j!~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  %V G/  
httpConnection.setRequestProperty("User-Agent","NetFox"); BcWcdr+}9  
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-XK0KYhgW  
int responseCode=httpConnection.getResponseCode(); F4#g?R::U  
if(responseCode>=400) JNI>VP[c  
{ ?WI3/>:<  
processErrorCode(responseCode); I_)*)d44_  
return -2; //-2 represent access is error o?Nu:&yE  
} +Lm4kA+aE5  
lU]un&[N  
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String sHeader; BbOu/i|  
\kIMDg3}  
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for(int i=1;;i++) ]DG?R68DQ  
{ >QE{O.Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9-1#( Y6S  
//Utility.log(in.readLine()); VaZn{z  
sHeader=httpConnection.getHeaderFieldKey(i); *O$CaAr\s  
if(sHeader!=null) gT+Bhr  
{ =s97Z-  
if(sHeader.equals("Content-Length")) VL+C&k v]  
{ '!h/B;*(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XE3aXK'R  
break; {QaNAR
=)  
} /TQ}} YVw  
} <lxD}DH=  
else 4DWwbO  
break; yq[Cq=rBk  
} n| O [a6G  
} zJlQ_U-!  
catch(IOException e){e.printStackTrace ();} Yj(4&&Q  
catch(Exception e){e.printStackTrace ();} 7^TV~E#  
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Utility.log(nFileLength); X&m'.PA  
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:&XH?/Wi  
return nFileLength; E:E4ulak  
} 0[A9b,MMVO  
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t/oN>mQG  
//保存下载信息（文件指针位置） NtGn88='{  
private void write_nPos() cS.i  
{ w)]H ^6  
try{ Bvjl-$m!v  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F
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output.writeInt(nStartPos.length); &p UZDjo?  
for(int i=0;i<nStartPos.length;i++) q6P wZ_  
{ Vn=qV3OE]  
// output.writeLong(nPos); KLQTKMNv  
output.writeLong(fileSplitterFetch.nStartPos); 2GmpCy`L"  
output.writeLong(fileSplitterFetch.nEndPos); mY!iu(R1  
} R\Z:n*  
output.close(); NF$\^WvYSP  
} qk(P>q8[  
catch(IOException e){e.printStackTrace ();} g+8hp@a  
catch(Exception e){e.printStackTrace ();} 1n*W2:,z  
} ,.IEDF<&  
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qa >Ay|92e  
//读取保存的下载信息（文件指针位置） [&S}dQ"  
private void read_nPos() 7cg*|E@  
{ 7sNw  
try{ 1YxgR}7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); vC;]jJb:  
int nCount = input.readInt(); 'BMy8  
nStartPos = new long[nCount]; $K~LM8_CKy  
nEndPos = new long[nCount]; oT
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for(int i=0;i<nStartPos.length;i++) $3+PbYY  
{ m(OvD!  
nStartPos = input.readLong();  r}_c  
nEndPos = input.readLong(); *~$~yM/~3U  
} #1-xw~_  
input.close(); h:\oly\  
} `Kl`VP=c  
catch(IOException e){e.printStackTrace ();} a@d=>CT$  
catch(Exception e){e.printStackTrace ();} .4.pJbOg  
} ({}(qm  
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@MR?6n*k  
private void processErrorCode(int nErrorCode) !hxIlVd
{  
{ X*oMFQgP  
System.err.println("Error Code : " + nErrorCode);
*DI)?  
} (LAXM x  
2i#Sn'1  
(kBP(2V  
//停止文件下载 p^m5`{1]x  
public void siteStop() 0Sl]!PZR1  
{ -5G)?J/*  
bStop = true; 96Wp!]*  
for(int i=0;i<nStartPos.length;i++) uUR~&8ERX  
fileSplitterFetch.splitterStop(); M<?Q4a'Q  
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} Jc4L5*Xn/  
} {y kYW%3s  
//负责部分文件的抓取 XV>JD/K2  
**FileSplitterFetch.java jMBiaX`
F  
*/ 5m$2Ku  
package NetFox; i@"e,7mSG  
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import java.io.*; |Yi)"-  
import java.net.*; ^{@!['  
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public class FileSplitterFetch extends Thread { `xS{0P{uj  
m@Ev~~;  
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String sURL; //File URL 7J$b$P0}  
long nStartPos; //File Snippet Start Position {0\,0*^p  
long nEndPos; //File Snippet End Position VU|dV\>  
int nThreadID; //Thread's ID T>>YNaUL  
boolean bDownOver = false; //Downing is over ;a"q'5+Ne  
boolean bStop = false; //Stop identical FeJr\|FT  
FileAccessI fileAccessI = null; //File Access interface tYW>t9  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "HMP$)d  
{ nCg66-3A  
this.sURL = sURL; EEy$w1ec  
this.nStartPos = nStart; d4[(8} x$/  
this.nEndPos = nEnd; 01a-{&   
nThreadID = id; u8
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 !,$i6gm  
} 1nj(hg  
qf'm=efRyu  
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public void run() {WN(&eax  
{ [ANuBNF  
while(nStartPos < nEndPos && !bStop) XP[uF ;w  
{ -XoPia2  
pI`?(5iK6|  
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try{ ^[:9fs  
URL url = new URL(sURL); W><Zn=G4)b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D?jk$^p~m#  
httpConnection.setRequestProperty("User-Agent","NetFox"); s)A<=)w/e  
String sProperty = "bytes="+nStartPos+"-"; %u{W7  
httpConnection.setRequestProperty("RANGE",sProperty); kW3E =pr  
Utility.log(sProperty); igf)Hb;5  
!%mAh81{&/  
$Byj}^;1  
InputStream input = httpConnection.getInputStream(); xk~IN%\  
//logResponseHead(httpConnection); &tR(n$M@>  
jPvDFT^d/  
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byte[] b = new byte[1024]; @=S}=cl  
int nRead; R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u?ek|%Ok  
{ 8Chj w wB  
nStartPos += fileAccessI.write(b,0,nRead); !4@G3Ae22  
//if(nThreadID == 1) #4LFG\s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $ 0|a;  
} U09.Y  
}'"Gr%jf(  
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Utility.log("Thread " + nThreadID + " is over!"); A?5E2T1L%.  
bDownOver = true; Zx }&c |Q  
//nPos = fileAccessI.write (b,0,nRead); Z]w#vL
R  
} vQVK$n`  
catch(Exception e){e.printStackTrace ();} bte~c  
} {'+QH)w(  
} z"4]5&3A  
XK(`mEi  
+KGZHO!  
//打印回应的头信息 =]R3& ]#n  
public void logResponseHead(HttpURLConnection con) 0X2@CPIFf  
{ ij5g^{_T;8  
for(int i=1;;i++) 8$N8}q%  
{ jd`},X/  
String header=con.getHeaderFieldKey(i); t
L SN`6[:  
if(header!=null) xZ5M/YSyG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wle@vCmr  
Utility.log(header+" : "+con.getHeaderField(header)); fBtm%f  
else W|k0R4K]]  
break; ~%u|[$  
} $S*4r&8ZD  
} Z!xVgM{  
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$$Vt7"F  
public void splitterStop() _;A $C(  
{ q}uHFp/J  
bStop = true; W_O)~u8  
} a\uie$"cr]  
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} gQSNU_o Z  
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/* xynw8;Y,  
**FileAccess.java 0XwHP{XaO  
*//文件访问(定位，写) :A46~UA!$  
package NetFox; :^ i9]  
import java.io.*; pqM~l&  
jkAAqRR  
RIM`omM  
public class FileAccessI implements Serializable{ "yziXT@V  
d&cU*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SQsSa1  
RandomAccessFile oSavedFile; M/D)".;  
long nPos; O/%< }3Sq  
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public FileAccessI() throws IOException e)nimq
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{ G |*(8r()  
this("",0); +,+vkpL-%  
} a^qNJ?R!  
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public FileAccessI(String sName,long nPos) throws IOException q+SD6qM  
{ 1PaUI#X"2F  
oSavedFile = new RandomAccessFile(sName,"rw"); A\rt6/  
this.nPos = nPos; <HWS:'1  
oSavedFile.seek(nPos); a~h:qpgc  
} bo"%0?3n  
5\mTr)\R  
1:C:?ZC#c  
public synchronized int write(byte[] b,int nStart,int nLen) n6WY&1ZE~  
{ 3OyS8`  
int n = -1; LL^q1)o  
try{ P=N$qz
$U  
oSavedFile.write(b,nStart,nLen); $FH18  
n = nLen; zxb/  
} i[C~5}%  
catch(IOException e) 'PZ|:9FX!  
{ 9DQ)cy  
e.printStackTrace (); TjWE_Bq]g  
} DVZdClAL  
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return n; uaw~r2  
} o!TQk{0  
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} $
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_Jz8{` "  
/* aeyNdMk-  
**SiteInfoBean.java D'<VYl"/  
*/ l@j.hTO<  
package NetFox; vgIpj3u  
%z]U LEYrZ  
*YTo{~  
public class SiteInfoBean { =d 2r6%v  
MfF~8  
#$~ba%t9%  
private String sSiteURL; //Site's URL r'LVa6e"N  
private String sFilePath; //Saved File's Path '[|+aJ  
private String sFileName; //Saved File's Name gie
N9S  
private int nSplitter; //Count of Splited Downloading File Z0!5d<  
L(S'6z~_9  
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public SiteInfoBean() Zv]x'3J#Y  
{//nSplitter的缺省值为5 <>xJn{f0c  
//default value of nSplitter is 5 -Lu)'+  
this("","","",5); ^Jp&H\gI.  
} (;x3} ]  
<>eOC9;VY  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mpC`Yk  
{ Ok5<TZ6t4k  
sSiteURL= sURL;  @4d)R  
sFilePath = sPath; i!2TH~zl  
sFileName = sName; oeSN9O  
this.nSplitter = nSpiltter; qL6c`(0  
(GnuWc\p  
`J<*9dq%  
} XLk<*0tp  
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public String getSSiteURL() @5
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{ 'X).y1'  
return sSiteURL; 0<"k8 k@J  
} <tpmUA[]  
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zepop19  
public void setSSiteURL(String value) ?SQE5Z  
{ |@?%Ct  
sSiteURL = value; !?f5>Bl  
} _EnwME{@  
C$Lu]pIL*  
r0t^g9K0  
public String getSFilePath() pA.J@,>`}  
{ >4Y3]6N0.F  
return sFilePath; rD?L  
} 2n><RZ/9  
=@Dwlze  
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public void setSFilePath(String value) 3K&4i'}V  
{ k 4/D8(OXw  
sFilePath = value; @WH@^u  
} ]$afC!Z  
G CRz<)1  
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public String getSFileName() `.x$7!zLC  
{ .Xm(D>>k  
return sFileName; ~AYN  
} sb:d>6  
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public void setSFileName(String value) ]A FI\$qB\  
{ ELrsx{p:  
sFileName = value; rn DCqv!'P  
} HCK|~k  
@uo ~nFj,  
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public int getNSplitter() -yxOBq  
{ ~pa!w?/bQ  
return nSplitter; IJTtqo  
} Qjx?ri//  
s?8<50s  
9[!,c`pw  
public void setNSplitter(int nCount) u&G.4QQF  
{ (>J4^``x=  
nSplitter = nCount; $VAx:Y|  
} jR=s#Xz  
} >56>*BHD  
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f)]%.>  
/* AV 8n(  
**Utility.java _'4A|-9  
*/ NmK8<9`u  
package NetFox; wB'zuPAK6  
6
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public class Utility { \ w3]5gJZ  
%B.D^]S1:  
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public Utility() mw_Ew]&  
{ *5bLe'^\|K  
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<Q|d&vDVfV  
} +q6ydb,  
'`'GK&)  
//线程睡眠 =b;>?dP  
public static void sleep(int nSecond) G!4(BGx&  
{ zf3v5Hk  
try{ yH][(o=2  
Thread.sleep(nSecond); AM=z`0so  
} kq\)MQ"/X  
catch(Exception e) .CP&bJP%  
{ s {^yj  
e.printStackTrace (); +_-bJo2a  
} :akT 'q#  
} I ZQHu h  
l & D
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//日志 t|t#vcB  
public static void log(String sMsg) kd"N29  
{ a^,(v  
System.err.println(sMsg); w[P4&?2:  
} f#ri'&}c :  
0"~i^  
"~TA SX_?  
public static void log(int sMsg) ?` SUQm  
{ XMG]Wf^%\<  
System.err.println(sMsg); \uss Uv  
} )M2F4[vcb  
} ;Eu3[[V  
54zlnM$  
q7u'_R,;  
/* UMX@7a,[3  
**TestMethod.java (a9d
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*/ \.M*lqI  
package NetFox; TLehdZ>^  
@cU&n6C@  
8enEA^  
public class TestMethod { :[;hu}!&  
[w ;kkMJAy  
\h8
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public TestMethod() -G6U$  
{ ///xx/weblogic60b2_win.exe Ty
88}V  
try{ Z`YJBcXR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e<r,&U$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qZ@s#UiB  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w3jO6*_ M  
fileFetch.start(); vq34/c^  
} =B.F;40  
catch(Exception e){e.printStackTrace ();} j65<8svl  
I%urz!CNE*  
^n0]dizB  
} :1Sl"?xU  
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public static void main(String[] args) +}jJ&Z9)  
{ Xr
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new TestMethod(); V)}rEX  
} v%Wx4v@%SE  
} ,AT[@  
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