http断点续传简单实现（java)

/* E6:p  
**SiteFileFetch.java "zbE  
*/ s?k[_|)!  
package NetFox; "44?n <1  
import java.io.*; &J$5+"/;X  
import java.net.*; Wi^rnr'Ss  
I?>T"nV +'  
)\vHIXnfJ1  
public class SiteFileFetch extends Thread { {R;M`EU>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7-I>53@  
long[] nStartPos; //开始位置 VU9P\|c@<  
long[] nEndPos; //结束位置 Cw $^w  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \F~Cbj+'Nu  
long nFileLength; //文件长度 G4' U;  
boolean bFirst = true; //是否第一次取文件 cg00t+  
boolean bStop = false; //停止标志 OL5HofgNm  
File tmpFile; //文件下载的临时信息 )H)Udhz  
DataOutputStream output; //输出到文件的输出流 CDnz &?  
9^ p{/Io  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |+-i'N9  
public SiteFileFetch(SiteInfoBean bean) throws IOException RWCS u$  
{ &pjV4m|j<  
siteInfoBean = bean; ~aAJn IO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y,btL'[W  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); f<Tz#w&6W  
if(tmpFile.exists ()) a +yI2s4Z  
{ !m(L0YH  
bFirst = false; I^(#\vRW  
read_nPos(); Aq%^>YAp  
} @T1+b"TC  
else ?3TV:fx"X  
{ ?VQLY=?  
nStartPos = new long[bean.getNSplitter()];  /;6@M=6u  
nEndPos = new long[bean.getNSplitter()]; 0WE1}.J<  
} ?7)(qnbe"  
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} I0+wczW,^  
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public void run() %@n8 ?l4  
{ lk1Gs{(qhH  
//获得文件长度 @B[Cc`IN"  
//分割文件 l/zC##1+.  
//实例FileSplitterFetch P<!$A  
//启动FileSplitterFetch线程 (%yc5+f!  
//等待子线程返回 7G(f1Y  
try{ V}fKV6 v9  
if(bFirst) > ' 0 ][~  
{ UvJuOh+  
nFileLength = getFileSize(); &v5.;8u+OV  
if(nFileLength == -1) _iJXp0g  
{ 8KwCwv  
System.err.println("File Length is not known!"); ;'QY<,p[e  
} e ]o'i;I  
else if(nFileLength == -2) $?J+dB  
{ igBrmaY'  
System.err.println("File is not access!"); o 7W Kh=  
} gT&'i(c  
else #z!Hb&Qi\  
{ M#VC3h$  
for(int i=0;i<nStartPos.length;i++) I9un  
{ $>"e\L4Kp  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `1bX.7K43  
} C]yQ "b  
for(int i=0;i<nEndPos.length-1;i++) h^+C)6(58n  
{ k\sM;bCv7  
nEndPos = nStartPos[i+1]; GyAgPz  
} U5CPkH1  
nEndPos[nEndPos.length-1] = nFileLength; o.3YM.B#  
} ]]=fA 4(  
} |4S?>e  
!Nl.Vb  
'nWs0iH.  
//启动子线程 9/1+BQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p^igscPF6  
for(int i=0;i<nStartPos.length;i++) )w2K&Zr0  
{ J4v0O="  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ct}%Mdg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), qJ+52U|z  
nStartPos,nEndPos,i); (;pi"/x[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Zfy
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fileSplitterFetch.start(); zf3:<CRX5  
} 
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T3 9C lH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X')Zm+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3<Z'F}lg  
nEndPos = " + nFileLength); %7v@n+Q  
// fileSplitterFetch[nPos.length-1].start(); kg: uGP9  
Fu4EEi  
f-3'D-{EKt  
//等待子线程结束 Cb{A:\>Q{  
//int count = 0; hzQ+9-qA  
//是否结束while循环 /}$T38  
boolean breakWhile = false; :
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8VuZ,!WH#  
while(!bStop) Y62u%':X  
{ wY3|#P CDV  
write_nPos(); y=9Dxst"V  
Utility.sleep(500); p2x1xv  
breakWhile = true; n{^<&GWox  

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n^AP"1l8?0  
for(int i=0;i<nStartPos.length;i++) 7"F|6JP"$c  
{ 4W!\4Va  
if(!fileSplitterFetch.bDownOver) BjyXQ9D  
{ | 7 m5P
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breakWhile = false; _}zo /kDA  
break; =@JS88+  
} n</k/Mk}  
} Z>x7|Q3CX  
if(breakWhile) m0|Ae@g~3  
break; 7Aio`&^  
@)vy'qP d  
t{Hh&HX  
//count++; 9^PRX  
//if(count>4) !@pV)RUv7  
// siteStop(); 4`8IFK  
} Dd0Qp-:2  
lI4J=8O0  
Q+b.-iWR  
System.err.println("文件下载结束！"); "7kgez#Y  
} mQJ4;BJw  
catch(Exception e){e.printStackTrace ();} =t3vbV  
} N.0HfYf  
M|UxE/  
YX ;n6~y  
//获得文件长度 (_w %  
public long getFileSize() 4ZI!,lv*  
{ w%3Fg~Up  
int nFileLength = -1;
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try{ ls"b#eFC#  
URL url = new URL(siteInfoBean.getSSiteURL()); lf%b0na?r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |66m` <  
httpConnection.setRequestProperty("User-Agent","NetFox"); fJLf7+q  
#\pP2  
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int responseCode=httpConnection.getResponseCode(); Dac ^*k=D  
if(responseCode>=400) 1C_'H.q<=  
{ w
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processErrorCode(responseCode); Ap]4QqU  
return -2; //-2 represent access is error {)B9Z I{+A  
} CKv&Re  
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,`<^F:xl  
String sHeader; _0,"vFdj  
8 7RHA $?  
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for(int i=1;;i++) (R_CUH  
{ !8xKf*y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); zmf"I[)  
//Utility.log(in.readLine()); /Hv*K&}M  
sHeader=httpConnection.getHeaderFieldKey(i); ,IIZXl@  
if(sHeader!=null) i8Fs0
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{ T3PX gL)o  
if(sHeader.equals("Content-Length")) ^|wT_k\  
{ WP0 #i~3*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); la'e[t7  
break; ku{XW8  
} NW{y%Z  
} 6Z~Ya\~.g.  
else >0PUWr$8  
break; f.||PH  
} m@ i2#  
} hPan  
catch(IOException e){e.printStackTrace ();} S8O
)/Sg=  
catch(Exception e){e.printStackTrace ();} 9>N\sOh  
u4:\UC'  
$ !v}xY  
Utility.log(nFileLength); 8r
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return nFileLength; F9MR5O"  
} Yeqvv  
q*L ]  
sNm,Fmuz:  
//保存下载信息（文件指针位置） BwC<rOU  
private void write_nPos() |*:tyP%m^  
{ ZB828T3  
try{ .i$,}wtw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^8:VWJM  
output.writeInt(nStartPos.length); "H>.':c"+3  
for(int i=0;i<nStartPos.length;i++) hG=k1T%=  
{ [UMLx  
// output.writeLong(nPos); ?VB#GJ0M9  
output.writeLong(fileSplitterFetch.nStartPos); eGLO!DdxZ  
output.writeLong(fileSplitterFetch.nEndPos); rO0ZtC{K  
} 'WK;$XQ  
output.close(); ;a|`s  
} =H[\%O~?b  
catch(IOException e){e.printStackTrace ();} [s~JceUyX  
catch(Exception e){e.printStackTrace ();} )ZGYhE  
} wW-Ab  
*=Doe2(!C  
:$=
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//读取保存的下载信息（文件指针位置） - %|P  
private void read_nPos() *zq.C  
{ h40'@u^W  
try{ : (gZgMT  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #+9rjq:v#]  
int nCount = input.readInt(); Y %K~w  
nStartPos = new long[nCount]; R'SBd}1  
nEndPos = new long[nCount]; LfEvc2 v=g  
for(int i=0;i<nStartPos.length;i++) BRb\V42i;  
{ 20aZI2sk`  
nStartPos = input.readLong(); S?L#N  
nEndPos = input.readLong(); Q!yb16J  
} XYe~G@Q Z  
input.close(); ,yICNtP  
} RlrZxmPV>O  
catch(IOException e){e.printStackTrace ();} X8Xn\E  
catch(Exception e){e.printStackTrace ();} s`"OM^[-  
} f')c/Yw  
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)GVBE%!WEd  
private void processErrorCode(int nErrorCode) d<x1*a  
{ Z`Ax pTl  
System.err.println("Error Code : " + nErrorCode); _#!U"hkH  
} 7R,qDp S  
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9JPEj-3`g  
//停止文件下载 ocF>LR%P  
public void siteStop() I5qM.@%zB  
{ 86%%n?"}  
bStop = true; %:3'4;jh%  
for(int i=0;i<nStartPos.length;i++) ?6f7ld5  
fileSplitterFetch.splitterStop(); 03EV%Vc  
|jT2W  
x? N.WABr;  
} C/G]v*MBQ  
} aG(hs J)  
//负责部分文件的抓取 w9f _b3  
**FileSplitterFetch.java 9_ZBV{   
*/ yHNuU)Ft  
package NetFox; ,}0$Tv\1  
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import java.io.*; H\E7o"m  
import java.net.*; %X>FVlPm  
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public class FileSplitterFetch extends Thread { U\jb"  
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String sURL; //File URL o
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long nStartPos; //File Snippet Start Position {~N3D4n^  
long nEndPos; //File Snippet End Position Hz@h0+h  
int nThreadID; //Thread's ID fW(/Loh  
boolean bDownOver = false; //Downing is over *KJB>W%@uM  
boolean bStop = false; //Stop identical E9+HS  
FileAccessI fileAccessI = null; //File Access interface pY
o=oI  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7+nm31,<O  
{ 0(y:$  
this.sURL = sURL; {\G`]r-cM  
this.nStartPos = nStart; +;Cr];b3  
this.nEndPos = nEnd; #DFp[\)1  
nThreadID = id; =gjDCx$|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 53Yxz3v  
} I[0!SIqY  
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_?`&JF?*  
public void run() xJc$NV-JzK  
{ pu9^e4B9  
while(nStartPos < nEndPos && !bStop) gCuAF$o  
{ ?Go!j?#a  
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try{ @;iXp>&&  
URL url = new URL(sURL); T\9~<"P^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WOX}Sw"  
httpConnection.setRequestProperty("User-Agent","NetFox"); yZCX S  
String sProperty = "bytes="+nStartPos+"-"; .[:VSM7T  
httpConnection.setRequestProperty("RANGE",sProperty); 8{0k0 &x  
Utility.log(sProperty); W:`#% :C  
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InputStream input = httpConnection.getInputStream(); vXv;1T  
//logResponseHead(httpConnection); PFrfd_s{>\  
]$A(9Pn"  
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byte[] b = new byte[1024]; IP3E9z_L  
int nRead; XNehPZYS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) GZ3 ]N  
{ mchJmZ{A  
nStartPos += fileAccessI.write(b,0,nRead); }Fa%%}  
//if(nThreadID == 1) J?&l*_m;t  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V'G Ju  
} ZmEEj-*7s  
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7 oQ[FdRn*  
Utility.log("Thread " + nThreadID + " is over!"); mi,&0xDea  
bDownOver = true; 9GU]l7C=z  
//nPos = fileAccessI.write (b,0,nRead); S`!-Cal`n  
} %lw! e  
catch(Exception e){e.printStackTrace ();} iW%8/
$  
} W*N$'%  
} Bv6K$4  
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//打印回应的头信息 z>m=h)9d~  
public void logResponseHead(HttpURLConnection con) P7.'kX9  
{ i-" p)2d=#  
for(int i=1;;i++) *\G)z|^yx  
{ 0bS|fMgc  
String header=con.getHeaderFieldKey(i); (R!hjw~  
if(header!=null) -0C@hM,wm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @-&MA
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Utility.log(header+" : "+con.getHeaderField(header)); T-_"|-k}P%  
else wkUlrL/~  
break; "IQ/LbOqm_  
} =
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} MGJ.,tK1  
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n'1'!J;
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public void splitterStop() PcT?<HU  
{ %]2,&  
bStop = true; fHRMu:q  
} {)8>jxQN  
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} kM8{Cw  
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/* #_93f |  
**FileAccess.java G<|8?6bq#  
*//文件访问(定位，写) @#g<IBG=*  
package NetFox; v59dh (:`Z  
import java.io.*; @.
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public class FileAccessI implements Serializable{ #Lv2Zoi>G  
6Orum/|h  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *z*uEcitW  
RandomAccessFile oSavedFile; c2t=_aAIPQ  
long nPos; Y_woKc*  
G3G#ep~)vC  
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public FileAccessI() throws IOException G 0%6ch^%  
{ %w7u]-tR  
this("",0); C?Bl{4-P}*  
} #|&Sc_#4)  
1i[FY?6`dh  
YG[;"QR  
public FileAccessI(String sName,long nPos) throws IOException #9-P%%kQ  
{ (0YZZ93  
oSavedFile = new RandomAccessFile(sName,"rw"); SN7"7joP<  
this.nPos = nPos; SCvVt  
oSavedFile.seek(nPos); #txE=e"&o  
} /+Lfrt  
AV9m_hZt  
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public synchronized int write(byte[] b,int nStart,int nLen) 7Mb#O_eh  
{ ojyIQk+  
int n = -1; S"wR%\NIp  
try{ .Asv%p[W  
oSavedFile.write(b,nStart,nLen); Lzu.)C@Amx  
n = nLen; ho##Z*O  
} =  C4  
catch(IOException e) EkgE_8  
{ &e6CJ  
e.printStackTrace (); &wD;SMr<  
} C{gyj}5  
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=R*qP;#  
return n; 3)\8%Ox  
} MrZh09y  
t2,A@2DU2  
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} ):i&`}SY  
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+qh[N@F  
/* Ut2y;2)a  
**SiteInfoBean.java H,Z;=N_  
*/ rE}%KsZ  
package NetFox; 1pArZzm>  
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public class SiteInfoBean { B!vmQR*1  
 IiY/(N+J  
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private String sSiteURL; //Site's URL Z?wU  
private String sFilePath; //Saved File's Path e,t(q(L  
private String sFileName; //Saved File's Name
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private int nSplitter; //Count of Splited Downloading File U}[I   
5$V_
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public SiteInfoBean() ZosP(Tdq  
{//nSplitter的缺省值为5 j#
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//default value of nSplitter is 5 N[s}qmPha  
this("","","",5); -$\+' \  
} b )B?
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{q"OM*L(  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) W[Ls|<Q  
{ {phNds%  
sSiteURL= sURL; &*+'>UEe5  
sFilePath = sPath; j'A_'g'^  
sFileName = sName; z^'gx@YD*v  
this.nSplitter = nSpiltter; Pi]19boM.  
.Y&)4+ckL  
:Zlwp6  
} ;M)QwF1  
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Tj:B!>>  
public String getSSiteURL() |S_eDjF  
{ -[cTx[Z,  
return sSiteURL; HMSO=)@+  
} Qk:
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public void setSSiteURL(String value) /;oX)]W  
{ gt@m?w(  
sSiteURL = value; kqFP)!37  
} '<"s \,  
@7I
IM{  
`@`CG[-9  
public String getSFilePath() 3kybLOG  
{ )h7<?@wv&  
return sFilePath; e)d`pQ6  
} <J)]mh dm  
'@_d(N1jTw  
|olA9mp|]  
public void setSFilePath(String value) nAv#?1cjz  
{ aDU<wxnSvO  
sFilePath = value; |?,A]|j  
} 1q7|OWFT  
f
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public String getSFileName() 8WXQOo8  
{ PvPOU"  
return sFileName; ,Q  
} jIJ~QpNE  
t'n pG}`tE  
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public void setSFileName(String value) A^USBv+9`  
{ JMC. w!  
sFileName = value; fp`;U_-&0  
} ;ub;lh3  
V<GHpFi0  
X $jWo@  
public int getNSplitter() ZOh`(})hy  
{ b,7k)ND1F  
return nSplitter; EJMM9(DQ7  
} =;Au<|  
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public void setNSplitter(int nCount) p{r}?a  
{ rC5 p-B%  
nSplitter = nCount; i@*{27t  
} ssfr}fzH  
} KcWN,!G  
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*4\:8  
/* V%rzk*LA  
**Utility.java @>,^":`#  
*/ ]cHgleHQ  
package NetFox; >g1~CEMN#  
q'T4w!V(V  
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public class Utility { e"{{ TcNk  
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j#!IuH\]  
public Utility() cr7 }^s  
{ _kef
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} L/$H"YOv  
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//线程睡眠 Ag-
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public static void sleep(int nSecond) , qMzWa  
{ fK>L!=Q  
try{ s
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Thread.sleep(nSecond); }Y12  
} n(1l}TJy  
catch(Exception e) @LF,O}[2J  
{ R0KPZv-  
e.printStackTrace (); ?gA 8x  
} )|ju~qbf  
} P)Jgs  
L+b6!2O,  
//日志
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public static void log(String sMsg) q+yQwX{  
{ f\|w'  
System.err.println(sMsg); n@<YI  
} 1+_`^|eK  
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*7uH-u"5d  
public static void log(int sMsg) ZF!h<h&,  
{ (
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System.err.println(sMsg); p$S*dr  
} 94'&b=5+  
} y6(Z`lx  
u|\1hLXX  
3#LlDC_WC  
/* %z=le7  
**TestMethod.java /C
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*/ uy>q7C  
package NetFox; p*XANGA  
T$8)u'-pa  
(~
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public class TestMethod { ; 5*&xz  
)3cAQ'w  
j`{?OYD  
public TestMethod() Y
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{ ///xx/weblogic60b2_win.exe HY56"LZ$(}  
try{ zYH&i6nj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8?xE6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )W^F2-{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?tWaI{95I  
fileFetch.start(); Yj&F;_~  
} )v'WWwXY>  
catch(Exception e){e.printStackTrace ();} 0_jf/an,%  
\[;0KV_  
)*$lp'~7N  
} O%\*@4zM  
fBU`k_  
6_(&6]}66  
public static void main(String[] args) d-oMQGOklb  
{ {a =#B)6  
new TestMethod(); W_JlOc!y  
} ld[I}88$  
} 3/P1!:g9  
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