http断点续传简单实现（java)

/* |wKC9O@%  
**SiteFileFetch.java bBkF,`/f$  
*/ \e5bxc  
package NetFox; Ly?gpOqu5  
import java.io.*; TR8
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import java.net.*; {XMF26C#  
/++CwRz@Gm  
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public class SiteFileFetch extends Thread { m<>3GF,5bP  
2$^n@<uZ@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ).TQYrs  
long[] nStartPos; //开始位置 ~+{OSx<S  
long[] nEndPos; //结束位置 7m6@]S6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 DiyviH  
long nFileLength; //文件长度 +$:bzo_u  
boolean bFirst = true; //是否第一次取文件 CT@JNG$<"  
boolean bStop = false; //停止标志 .kSx>3  
File tmpFile; //文件下载的临时信息 6@-VLO))O  
DataOutputStream output; //输出到文件的输出流 Kr!(<i  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） P1b5=/}:V  
public SiteFileFetch(SiteInfoBean bean) throws IOException vMsb@@O\\  
{ 6mJa  
siteInfoBean = bean; x8Rmap@L.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3T$gT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Kb~s'cTxIO  
if(tmpFile.exists ()) m}] bP  
{ @Y'BqDFlZ  
bFirst = false; LL+ROX^M  
read_nPos(); >A#wvQl7   
} }g:y!pk  
else nz:I\yA  
{ gG0P &9xz  
nStartPos = new long[bean.getNSplitter()]; Kc+;"4/#q  
nEndPos = new long[bean.getNSplitter()]; K.?~@5%  
} ve2GRTO^aC  
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} XSkN
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 h&\%~LO.  
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public void run() -b"7WBl  
{ yjODa90!G  
//获得文件长度 JPQ[JD^]  
//分割文件 wSHE~Xx  
//实例FileSplitterFetch r>1M&Y=<  
//启动FileSplitterFetch线程 5|!x0H;  
//等待子线程返回 -o<L%Y<n2  
try{ 9^Q:l0|  
if(bFirst) *a*\E R  
{ a;J{'PHu  
nFileLength = getFileSize(); 5 T1M:~u i  
if(nFileLength == -1) Q}~of}h/  
{ Z-`j)3Y  
System.err.println("File Length is not known!"); JnCp'`  
} ]%jlaXb  
else if(nFileLength == -2) c#M'Mye  
{ (.,`<rXw  
System.err.println("File is not access!"); ps1ndGp~#  
} 3!M;Z7qF]  
else beFVjVVHq  
{ oR>o/$z$)g  
for(int i=0;i<nStartPos.length;i++) ;/#E!Ja/u  
{ nj99!"_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); T_bk%  
} kVk^?F  
for(int i=0;i<nEndPos.length-1;i++) 5K13   
{ i.Iiwe0G  
nEndPos = nStartPos[i+1]; >;}np F>  
} Fx2z lM&  
nEndPos[nEndPos.length-1] = nFileLength; >VnkgY  
} _Z'j%/-4@D  
} })O^xF~  
/gZrnd?  
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//启动子线程 S~fQ8t70  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $e#p -z  
for(int i=0;i<nStartPos.length;i++) l\7NR  
{ 4Y5Q>2D}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BRF=TL5Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), fyIL/7hzf4  
nStartPos,nEndPos,i); Xxcv5.ug  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3+_? /}<  
fileSplitterFetch.start(); _V6jn~N  
} lj$\2B  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8FyJo.vr(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %m]9";  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", } 5i0R  
nEndPos = " + nFileLength); Z.+-MNWV  
// fileSplitterFetch[nPos.length-1].start(); ZzPlIl}\  
ucQ2/B#'4l  
Mw2?U>h1  
//等待子线程结束 -M}#-qwf  
//int count = 0; ;u!qu$O  
//是否结束while循环 &/*XA  
boolean breakWhile = false; ;:Q 5?zM  
+L1%mVq]y  
I#QBJ#  
while(!bStop) !_rAAY  
{ [=079UN-X  
write_nPos(); a9PSg/p  
Utility.sleep(500); _hyboQi  
breakWhile = true; {s!DRc]ln  
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for(int i=0;i<nStartPos.length;i++) J<Di2b+  
{ preKg$U  
if(!fileSplitterFetch.bDownOver) yS0YWqv]6@  
{ @O9.~6  
breakWhile = false; N*w/\|  
break; kFmd):U!R  
} %7 h_D  
} 4VINu9\V  
if(breakWhile) mw)KyU#l,:  
break; @Y+YN;57  
p@]\N  
}N^.4HOS8  
//count++; h}fz`ti U  
//if(count>4) d)F~)}TFM  
// siteStop(); K.c6n,'  
} 8<ZxE(v  
q y7
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57IAH$n8o  
System.err.println("文件下载结束！"); YG ,  
} 3RG*:9  
catch(Exception e){e.printStackTrace ();} :5hKE(3Q  
} ocBfs^ aW  
[YG\a5QK  
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//获得文件长度
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public long getFileSize() <4SY'-w  
{ IMLk{y%6  
int nFileLength = -1; O\;Z4qn2=  
try{ )$K )`uqb  
URL url = new URL(siteInfoBean.getSSiteURL());  f.acH]p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5Z/xY&  
httpConnection.setRequestProperty("User-Agent","NetFox"); NfizX!w&  
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!Kr|04Qp#x  
int responseCode=httpConnection.getResponseCode(); Q!8AFLff4  
if(responseCode>=400) \}Fx''  
{ U 2am1}  
processErrorCode(responseCode); QPf*!E  
return -2; //-2 represent access is error xo2PxU
O  
} heJI5t,  
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String sHeader; [:<CgU9C  
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for(int i=1;;i++) `s93P^%  
{ ]V*s-och'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :U_k*9z}=
 
//Utility.log(in.readLine()); cM%I5F+n  
sHeader=httpConnection.getHeaderFieldKey(i); _$%.F|:  
if(sHeader!=null) _7r<RZ  
{ :N$^x /{  
if(sHeader.equals("Content-Length")) vgY ) L  
{ <uZ r.X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6lw)L  
break; Q qGf*  
} Oz(0$c  
} 1y@d`k`t:  
else pEgQ) 9\  
break; 8qGK"%{ ~  
} ("-Co,4ey  
} ApHs`0=(  
catch(IOException e){e.printStackTrace ();} [4L[.N@  
catch(Exception e){e.printStackTrace ();} #DK@&Gv  
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Utility.log(nFileLength); ax$ashFO/!  
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return nFileLength; .vsrZ_y?  
} <[mT*   
_'DT)%K  
5(RFkZn4[  
//保存下载信息（文件指针位置） jMv qKJ(<  
private void write_nPos() " &2Kvsz  
{ "D#+:ix8G|  
try{ 91%QO?hz  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FG/".dU  
output.writeInt(nStartPos.length); KZoIjK]  
for(int i=0;i<nStartPos.length;i++) -7E)u  
{ zOJ4I^^  
// output.writeLong(nPos); R-8>,  
output.writeLong(fileSplitterFetch.nStartPos); \]R
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output.writeLong(fileSplitterFetch.nEndPos); 6;s.%W  
} PyQt8Qlz  
output.close(); pQv`fr=  
} ]DVZeI03@  
catch(IOException e){e.printStackTrace ();} k4:$LFw@  
catch(Exception e){e.printStackTrace ();} K|Jp
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} U-~cVk+LI  
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//读取保存的下载信息（文件指针位置） BfZAK0+*$  
private void read_nPos() n;&08M5an}  
{ EB R,j_  
try{ ,z<J`n  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E4;vC ?K{  
int nCount = input.readInt(); 8~*<s5H  
nStartPos = new long[nCount]; x!5b"  "  
nEndPos = new long[nCount];  I/YBL  
for(int i=0;i<nStartPos.length;i++) 8@;|x2=y  
{ k1Z"Qmz  
nStartPos = input.readLong(); sa8JN.B  
nEndPos = input.readLong(); +tOmKY  
} j9Qd 45  
input.close(); <12ia"}  
} ?VCdT`6=  
catch(IOException e){e.printStackTrace ();} U9w0kcUw#J  
catch(Exception e){e.printStackTrace ();} 4lrF{S8  
} wUb5[m  
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{A!1s;  
private void processErrorCode(int nErrorCode) -u
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{ r{NC
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System.err.println("Error Code : " + nErrorCode); P5$d
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} aumWU{j=  
u|]{|Ya'%  
6/{V#.(  
//停止文件下载
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public void siteStop() ."`mh&+`  
{ >]b>gc?3  
bStop = true; &CP0T:h  
for(int i=0;i<nStartPos.length;i++) 9$ GAs  
fileSplitterFetch.splitterStop(); as#_Fer`U  
O7<--  

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} r 0mA  
} ?\Fo|__  
//负责部分文件的抓取 yFt$L'#  
**FileSplitterFetch.java )?_x$GKY  
*/ J)R2O{z  
package NetFox; _(A9k{  
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import java.io.*; [=3f:
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import java.net.*; >~%!#,C(|U  
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_#f+@)vR  
public class FileSplitterFetch extends Thread { `)i'1E[9  
8ckcTNPu  
_6U=7<f  
String sURL; //File URL vP k\b 3E  
long nStartPos; //File Snippet Start Position Pv-El+e!  
long nEndPos; //File Snippet End Position [\i0@  
int nThreadID; //Thread's ID |76G#K~<X  
boolean bDownOver = false; //Downing is over 6f=,$:S$  
boolean bStop = false; //Stop identical ~HW8mly'  
FileAccessI fileAccessI = null; //File Access interface .kbo]P  
Z\1*g k  
,[gu7z^|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %IAZU c  
{ ?HD eiJkX  
this.sURL = sURL; vI84=n  
this.nStartPos = nStart; W~" 'a9H/  
this.nEndPos = nEnd; 7E0L-E=.  
nThreadID = id; ajr);xd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _ ^ JhncL  
} K;ncviGu  
[u?*' c{  
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public void run() _aJo7  
{ Z
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while(nStartPos < nEndPos && !bStop) vw.rkAGY  
{ f&=WgITa  
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p?@R0]  
try{  5yA1<&z  
URL url = new URL(sURL); 3EY>XS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 30BFwNE  
httpConnection.setRequestProperty("User-Agent","NetFox"); s)dL^lj;  
String sProperty = "bytes="+nStartPos+"-";  !' }  
httpConnection.setRequestProperty("RANGE",sProperty); b\Wlpb=QZ  
Utility.log(sProperty); j<*  
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k4HE'WY  
InputStream input = httpConnection.getInputStream(); S*aMUV&  
//logResponseHead(httpConnection); ,Wbr; zb  
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Q4H(JD1f)  
byte[] b = new byte[1024]; N}|<P[LW  
int nRead; g$^:2MT"aQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1')_^
]  
{ /m"#uC!\  
nStartPos += fileAccessI.write(b,0,nRead); pxGDzU  
//if(nThreadID == 1) _ ^2\/@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); # dA-dN  
} o$4i{BL  
{4C/ZA{|l  
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Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; T"bH{|:%*=  
//nPos = fileAccessI.write (b,0,nRead); bmid;X|  
} fen~k#|l  
catch(Exception e){e.printStackTrace ();} AhyV  
} UnE[FYx  
} |>'.(
 
},]G +L;R  
$ [t7&e  
//打印回应的头信息 {s{bnU  
public void logResponseHead(HttpURLConnection con) _ArN
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{ ~[N"Q|D3Y  
for(int i=1;;i++)
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{ $>M-oNeC  
String header=con.getHeaderFieldKey(i); w7#9t  
if(header!=null) `GpOS_;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); On`T p
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Utility.log(header+" : "+con.getHeaderField(header)); 1(YEOZ  
else qH=<8Iu  
break; bb4
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}  %"jp':  
} Au\j6mB  
Lu][0+-  
swTur  
public void splitterStop() ,N1I\f  
{ /0_^Z2  
bStop = true; cWU9mzsE  
} *+Ugr
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} G u
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/* \*+-Bm:$j  
**FileAccess.java o,q47W=7$  
*//文件访问(定位，写) yQ03&{#  
package NetFox; o0)k5P~<~  
import java.io.*; Lu.C+zgQ  
@ L=dcO{r  
qib4DT$v-6  
public class FileAccessI implements Serializable{ _!ITCkBj  
W1!Nq`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 j*fs [4  
RandomAccessFile oSavedFile; H[DBL  
long nPos; vU9j|z  
Z(|'zAb^  
3 q^^Os  
public FileAccessI() throws IOException X+%5q =N  
{ s[n*fV']A  
this("",0); 1w$X;q"  
} #*tWhXU  
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public FileAccessI(String sName,long nPos) throws IOException #wS/QrRE  
{ U3tA"X.K  
oSavedFile = new RandomAccessFile(sName,"rw"); ~gi,ky^!  
this.nPos = nPos; &_o.:SL|  
oSavedFile.seek(nPos); tj1M1s|a  
} Nu[0X  
&a9Y4~e::  
3*C|"|lJ  
public synchronized int write(byte[] b,int nStart,int nLen) t,IQ|B&0  
{ Oh'C[  
int n = -1; 6V&HlJH  
try{ c?t,,\o(}  
oSavedFile.write(b,nStart,nLen); x!`~+f.6  
n = nLen; mM;5UPbZ  
} T$pBgS>  
catch(IOException e) {x\lK;  
{ .Gcs/PN  
e.printStackTrace (); *1b1phh0/  
} ]m=2 $mK  
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return n; o/\f+iz7  
} 5)=YTUCk  
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} =8W'4MC  
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@UwDsx&2(t  
/* ++|vy~T  
**SiteInfoBean.java +'ADN!(B_  
*/ \2OjIEQ
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package NetFox; 9>!B .Z?!#  
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public class SiteInfoBean { E%e2$KfD  
w(cl,W/w  
cz.,QIt_  
private String sSiteURL; //Site's URL =g^k$ Rc  
private String sFilePath; //Saved File's Path .[:2M9Rx  
private String sFileName; //Saved File's Name VI(2/**  
private int nSplitter; //Count of Splited Downloading File U6Xi-@XP  
#7BX,jvn>  
\ ~uY);  
public SiteInfoBean() \agT#tTJ  
{//nSplitter的缺省值为5 h/xV;oj  
//default value of nSplitter is 5 .?dYY;P  
this("","","",5); W_FN*Er  
} 0UN65JBuD  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R.)w l  
{ @lu`oyM  
sSiteURL= sURL; /=+Bc=<lZ  
sFilePath = sPath; ~0T,_N  
sFileName = sName; $(N+E,XB  
this.nSplitter = nSpiltter; Sc,ajT  
3c[< #]8S  
-,
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} !+{$dB>a  
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public String getSSiteURL() bVW2Tjc:  
{ oBI@.&tG}  
return sSiteURL; g?>V4WF  
} T@gm0igW/;  
Q)%a2s;  
bc%N !d  
public void setSSiteURL(String value) c?7Wjy  
{ OqlP_^Zz7p  
sSiteURL = value; BQF7S<O
+  
} TBu[3X%  
[e?vqm .  
y#?AW`|  
public String getSFilePath() 6[S-%|f  
{ |L%d^m  
return sFilePath; M0Vs9K=  
}
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SE0&CV4  
]h4r@L3  
public void setSFilePath(String value) V4tObZP3Ff  
{ AB[#
  
sFilePath = value; ^7-l<R[T  
} @*"H{xo.U  
"Wn8}T*  
V)#rP?Y  
public String getSFileName() L3|~ i&k  
{ #:M <<gk  
return sFileName; D?`|`Mu  
} !6pE0(V^+4  
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public void setSFileName(String value) k:*(..!0z  
{ iVAAGZ>am  
sFileName = value; GQ])y  
} 1<$z-y'  
lm\~_ 4l1  
j=y{ey7Fd  
public int getNSplitter() dvPlKLp  
{ ||o :A  
return nSplitter; D{G~7P\.  
} zA%$l&QN]  
{"n=t`E)3  
&KPJB"0L  
public void setNSplitter(int nCount) o8!uvl}:9  
{ WwAvR5jq  
nSplitter = nCount; R,f"2 k  
} 3R)_'!R[B  
} \>lDM  
]mdO3P  
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/* [
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**Utility.java z!>ml3  
*/ Rr"D)|Y;C(  
package NetFox; *z6m644H  
1vUW$)?X  
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public class Utility {
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AroYDR,3+  
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public Utility() CaqqH`/E4  
{ L{uQ:;w1  
/ &#b*46  
C{2y*sx  
} {~{</ g/  

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//线程睡眠 P?$Iht.^
 
public static void sleep(int nSecond) >NjgLJh  
{ }Sv\$h  
try{ HsRQiai*  
Thread.sleep(nSecond); &09g0K66  
} !lk9U^wnd  
catch(Exception e) ,*j@Zb_r  
{ S?e*<s9k  
e.printStackTrace (); Y7WU4He L  
} \z[L=  
} Kl]LnN%A{  
a n,$Z,G#K  
//日志 _ Y8jl,J  
public static void log(String sMsg) jrZH1dvE  
{ +hUz/G+3  
System.err.println(sMsg); 2'5
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} +?bjP6w_g  
z,IUCNgM  
H:!pFj  
public static void log(int sMsg) 4$MV]ldUI  
{ ,@r 0-gL  
System.err.println(sMsg); 'q, L*  
} NW`L
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} SeIL   
^_!2-QY.~  
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/* F|^tRL-  
**TestMethod.java #S') i1;  
*/ 66Bx,]"6  
package NetFox; h7cE"m  
2R>!Wj'G+o  
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public class TestMethod { Tv /?-`Y  
8Q\ T,C  
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1  
public TestMethod() tde&w=ec  
{ ///xx/weblogic60b2_win.exe u]jvXPE6  
try{ M:d} P  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =v49[i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 
MKZq*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >o|.0aw<  
fileFetch.start(); 3R6=C~  
} I|R;)[;X  
catch(Exception e){e.printStackTrace ();} VGeyZ\vU  
0W!S.]^1  
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} [kL`'yi  
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C
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public static void main(String[] args) 9Je+|+s]  
{ CjZIBMGc  
new TestMethod(); 6![}Jvu>  
} QM4O|x[   
} @nxpcHj  
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