http断点续传简单实现（java)

/* k FD;i  
**SiteFileFetch.java q`a'gJx#y  
*/ 1#2 I  
package NetFox; MUc$j&  
import java.io.*; @ioJ]$o7  
import java.net.*; E_wCN&`[  
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public class SiteFileFetch extends Thread { lU\[aNs  
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SiteInfoBean siteInfoBean = null; //文件信息Bean UHkMn  
long[] nStartPos; //开始位置 N!=v4f  
long[] nEndPos; //结束位置 gO- _  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 pa3{8x{9m  
long nFileLength; //文件长度 OLGE!&!>  
boolean bFirst = true; //是否第一次取文件 7U"g3a)=  
boolean bStop = false; //停止标志 itP,\k7>d  
File tmpFile; //文件下载的临时信息 =BAr .m+"  
DataOutputStream output; //输出到文件的输出流 _8J.fT$${  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $GcqBg-Hi  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]p GL`ge5  
{ 6l x>>J!H  
siteInfoBean = bean; I6av6t}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p)-^;=<B3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /Iokf@5  
if(tmpFile.exists ()) #q$HQ&k  
{ ()?(I?I
I  
bFirst = false; O _ gGf  
read_nPos(); lgy<?LI\  
} !i}w~U<  
else tSUEZ62EY  
{ Y\P8v  
nStartPos = new long[bean.getNSplitter()]; I;(L%TT `  
nEndPos = new long[bean.getNSplitter()]; 7Q9 w?y~c  
} "+nRGEs6  
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} ksUcx4;a@F  
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public void run() T3<4B!UB&  
{ '<)n8{3Q5w  
//获得文件长度 .2t4tb(SUw  
//分割文件 AV]2euyn  
//实例FileSplitterFetch my1@41 H  
//启动FileSplitterFetch线程 l|[N42+  
//等待子线程返回 *:7rdzn  
try{ v!-pSa)3  
if(bFirst) J]'zIOQ  
{ ^uc=f2=>,  
nFileLength = getFileSize(); {}n^cq  
if(nFileLength == -1) SKN`2hD  
{ u c)eil  
System.err.println("File Length is not known!"); Dx?,=~W9  
} JXQO~zj  
else if(nFileLength == -2) fTec  
{ 9W5lSX#^;  
System.err.println("File is not access!"); *N<]Xy@  
} ,ZNq,$j  
else V f&zL Sgr  
{ "HIRTE;&  
for(int i=0;i<nStartPos.length;i++) sll\g  
{ PFjL1=7I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9$
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} qe#tj/aZ  
for(int i=0;i<nEndPos.length-1;i++) 0[(8  
{ ? OM!+O  
nEndPos = nStartPos[i+1]; 1CZgb  
} T7%S #0,p  
nEndPos[nEndPos.length-1] = nFileLength; 6d}lw6L  
} /{_:{G!Q0  
}
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//启动子线程 h438`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (?c"$|^J  
for(int i=0;i<nStartPos.length;i++) FVKTbvYn  
{ 7n<{tM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UI0VtR]   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +O{*M9B  
nStartPos,nEndPos,i); Zu[su>\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _V6ukd"B~  
fileSplitterFetch.start(); b8UO,fY q  
} #c!lS<z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Lk8ek}o'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $6 f3F?y7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cm+Es6
;  
nEndPos = " + nFileLength); TD0 B%  
// fileSplitterFetch[nPos.length-1].start(); Wac&b  
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va@Lz&sAE%  
//等待子线程结束 k4J+J.|  
//int count = 0; r#a=@  
//是否结束while循环 oG\Vxg*  
boolean breakWhile = false;
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while(!bStop) +r2-S~f3N  
{ Jnov<+  
write_nPos(); d$!RZHo10V  
Utility.sleep(500); V 5mTP'  
breakWhile = true; g) jYFfGfH  
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}Sv:`9=  
for(int i=0;i<nStartPos.length;i++) Y$_B1_  
{ wc4=VC"y  
if(!fileSplitterFetch.bDownOver) 0GeTSFj  
{ WOap+  
breakWhile = false; GD$l||8  
break; )y$(AJx$  
} 46h<,na?,  
}  qX{+oy5  
if(breakWhile) li.;IWb0+)  
break; m{HS0l'  
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//count++; kffcm/  
//if(count>4) ~]2K^bh8&  
// siteStop(); ~9@UjQ^)F  
} kxv1Hn"`{E  
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System.err.println("文件下载结束！"); R\[e!g*I  
} sPIn|d  
catch(Exception e){e.printStackTrace ();} FZnw0tMq  
} 3!]rmZ-W  
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> ~O.@|  
//获得文件长度 Gd85kY@w7  
public long getFileSize() JWxwJex  
{ ?Ir:g=RP*  
int nFileLength = -1; ym1Y4,  
try{ &6VnySE?  
URL url = new URL(siteInfoBean.getSSiteURL()); P&Vv/D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7%M_'P4 V  
httpConnection.setRequestProperty("User-Agent","NetFox"); wibNQ`4k  
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int responseCode=httpConnection.getResponseCode(); ;2QP7PrSY  
if(responseCode>=400) T>W,'H  
{ ]Y&VT7+Z  
processErrorCode(responseCode); ;$g?T~v7  
return -2; //-2 represent access is error @r1_U,0e  
} 5{,<j\#L  
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String sHeader; Z%UP6%  
8}:nGK|kx  
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for(int i=1;;i++) ]`WJOx4  
{ $6IJP\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Nh+H9  
//Utility.log(in.readLine()); 5z)~\;[ -  
sHeader=httpConnection.getHeaderFieldKey(i); &rR2,3r=  
if(sHeader!=null) N;%6:I./  
{ f$QNg0v  
if(sHeader.equals("Content-Length")) v3>UV8c'  
{ m1AJ{cs  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); om>KU$g  
break; 8&dF  
} *oix6  
} Aos+dP5h,8  
else #/37V2E  
break;
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} F!K>Kz  
} lyhiFkO iH  
catch(IOException e){e.printStackTrace ();} A=0'Ks  
catch(Exception e){e.printStackTrace ();} Vxt+]5X  
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Utility.log(nFileLength); veECfR;  

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return nFileLength; u ^RxD^=L  
} LDa1X2N  
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//保存下载信息（文件指针位置） _q^E,P  
private void write_nPos() `Q,H|hp;k;  
{ <~=Vg  
try{ a8Wwq?@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); xgtR6E^k  
output.writeInt(nStartPos.length); yB6?`3A:  
for(int i=0;i<nStartPos.length;i++) -UT}/:a  
{ O#r%>;3*  
// output.writeLong(nPos); ;dhQN}7  
output.writeLong(fileSplitterFetch.nStartPos); sDV Q#}a  
output.writeLong(fileSplitterFetch.nEndPos); V(*
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} =2x^nW  
output.close(); 7 X4LJf  
} 7K:PdF>/  
catch(IOException e){e.printStackTrace ();} \73ch  
catch(Exception e){e.printStackTrace ();} i@J;G`  
}  9gZ$
 
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//读取保存的下载信息（文件指针位置） kG*~|ma  
private void read_nPos() fF kj+  
{ BDVtSs<7  
try{ 8dhUBJ0_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =vhm}  
int nCount = input.readInt(); <a+Z;>  
nStartPos = new long[nCount]; |Q>IrT  
nEndPos = new long[nCount]; a'IdYW0  
for(int i=0;i<nStartPos.length;i++)
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{ tLmTjX .6  
nStartPos = input.readLong(); teVM*-  
nEndPos = input.readLong(); 4KrL{Z+}  
} T6k0>[3xf  
input.close(); 3+bt~J0  
} Aiea\jBv  
catch(IOException e){e.printStackTrace ();} Wm5dk9&x  
catch(Exception e){e.printStackTrace ();} rVsJ`+L  
} Af{"pzY  
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private void processErrorCode(int nErrorCode) gZ1?G-Q  
{ bN@ l?w  
System.err.println("Error Code : " + nErrorCode); cN9t{.m  
} u<&m]]*  
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.%QXzIa3F  
//停止文件下载 ~PNub E  
public void siteStop() W@!S%Y9  
{ ;9g2?-svw  
bStop = true; OZ!^ak  
for(int i=0;i<nStartPos.length;i++) L8 @1THY  
fileSplitterFetch.splitterStop(); h)nG)|c  
" 2Dngw  
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}
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} *uvQ\.  
//负责部分文件的抓取 \nqS+on]  
**FileSplitterFetch.java 0qT%!ku&  
*/ Wo,?+I  
package NetFox; c[Zje7 @  
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import java.io.*; dC4'{n|7  
import java.net.*; 7"xd1l?zz  
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public class FileSplitterFetch extends Thread { ws^ np  
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String sURL; //File URL N)>ID(}F1  
long nStartPos; //File Snippet Start Position 5NLDYi@3  
long nEndPos; //File Snippet End Position yR.Ong  
int nThreadID; //Thread's ID 76` .Y  
boolean bDownOver = false; //Downing is over ,,|^%Ct']  
boolean bStop = false; //Stop identical ei5~&  
FileAccessI fileAccessI = null; //File Access interface n?K  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c6/=Gq
{.  
{ sUm'  
this.sURL = sURL; W+1^4::+  
this.nStartPos = nStart; uUw5l})%Fi  
this.nEndPos = nEnd; & "B=/-(  
nThreadID = id; Jpo(Wl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D7qOZlX16  
} kz7(Z'pw  
4I5Y,g{6+  
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public void run() IdxzE_@  
{ vSLtFMq^(  
while(nStartPos < nEndPos && !bStop) G<;*SYAb  
{ sFTy(A/  
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try{ $,fX:x  
URL url = new URL(sURL); EDs\,f}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _t}WsEQ+P  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5+ MS^H  
String sProperty = "bytes="+nStartPos+"-"; $ o#V#  
httpConnection.setRequestProperty("RANGE",sProperty); b\+`e
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Utility.log(sProperty); fLAw12;^  
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InputStream input = httpConnection.getInputStream(); w"&n?L  
//logResponseHead(httpConnection); eGbG
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byte[] b = new byte[1024]; !_Z&a  
int nRead; "G9xM
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?#Q #u|~  
{ MR.'t9m2L  
nStartPos += fileAccessI.write(b,0,nRead); 2T[9f;jM'  
//if(nThreadID == 1) p
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Xm2z}X(%  
} S?BG_J6A7  
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1 I",L&S1  
Utility.log("Thread " + nThreadID + " is over!"); Ef13Q]9|  
bDownOver = true; 0Z]!/AsC  
//nPos = fileAccessI.write (b,0,nRead); YkQd  
} eO[b1]WLP  
catch(Exception e){e.printStackTrace ();} g95`.V}  
} @2v_pJy^  
} z,%$+)K  
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//打印回应的头信息 !m?-!:  
public void logResponseHead(HttpURLConnection con) d9|<@A  
{ 3|Xyl`i4o  
for(int i=1;;i++) "`1bA"E  
{ }?v )N).kW  
String header=con.getHeaderFieldKey(i); Z>#i**  
if(header!=null) 2Q:+
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^&Y#)II  
Utility.log(header+" : "+con.getHeaderField(header)); ~2khgZ  
else 0%I=d  
break; @>H75  
} ,UdVNA  
} 4x[S\,20  
07=mj%yV  
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public void splitterStop() x`)&J B  
{ G[q$QB+  
bStop = true; `%WU8Yv  
} Uq`'}Vo  
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} {h`uV/5@`  
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/* 1|-Dj|  
**FileAccess.java 8E]F$.6U  
*//文件访问(定位，写) RhLVg~x  
package NetFox; 3I-MdApT  
import java.io.*; o J;$sj  
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public class FileAccessI implements Serializable{ e'b(gD}
 
8 uwq-/$  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 n^6j9FQ7  
RandomAccessFile oSavedFile; N^:9Fz  
long nPos; -4_$lnw$  
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public FileAccessI() throws IOException sYf~c0${  
{ G{%L
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this("",0); fNZ__gO!%  
} t |A-9^t'!  
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public FileAccessI(String sName,long nPos) throws IOException s#=7IH30  
{ m5Di=8  
oSavedFile = new RandomAccessFile(sName,"rw"); N7R!C)!IL  
this.nPos = nPos; '}bgLv  
oSavedFile.seek(nPos); ;cN{a&  
} >[=^_8M  
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public synchronized int write(byte[] b,int nStart,int nLen) \&gB)czEO  
{ HEc+;O1<
 
int n = -1; X1vd'
>  
try{ M{hg0/}sUW  
oSavedFile.write(b,nStart,nLen); qR+!l(  
n = nLen; !^Y(^RS@  
} 6MdiY1Lr!K  
catch(IOException e) agW@{c  
{ UH/\  
e.printStackTrace (); ,f;}|d:r  
} 2Dj%,gaR  
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return n; M%;hB
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} L.0mk_&  
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} Q%mB|i|  
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/* HYSIN^<oy  
**SiteInfoBean.java tr}Loq\y  
*/ *CTlOy  
package NetFox; `t'W2X  
{ W{
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public class SiteInfoBean { N `F~n%N  
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private String sSiteURL; //Site's URL k%QpegN  
private String sFilePath; //Saved File's Path l u%}h7ng  
private String sFileName; //Saved File's Name 9kS^Abtk  
private int nSplitter; //Count of Splited Downloading File &t:Gx<]  
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public SiteInfoBean() $F+ LDs  
{//nSplitter的缺省值为5 |f_[\&<*  
//default value of nSplitter is 5 A*P|e-&Q8  
this("","","",5); t+T4-1 3a  
} 74k dsgQf  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mg.kr:  
{ 3/W'V,5G6  
sSiteURL= sURL; 3c6b6  
sFilePath = sPath; oij}'|/Jc  
sFileName = sName; .qZ
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this.nSplitter = nSpiltter; z]`k#O%%)  
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} <oA7'|Bu<  
2OR{[L*  
b:]V`uF?  
public String getSSiteURL() A='N=^Pm  
{ y^v6AM
 
return sSiteURL; 0rG^,(3m  
} ?8Z0Gqt74  
.-oxb,/  
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public void setSSiteURL(String value) q]e`9/U  
{ O%KsD[W;  
sSiteURL = value; =Bhe'.]QSx  
} qPy1;maX
P  
kN4{13Qs*  
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public String getSFilePath() k" PayyAC  
{ 5T2
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return sFilePath; ``\i58K{e  
} EL 8<U  
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public void setSFilePath(String value) :hFIl0$,"3  
{ 4Vi`* !  
sFilePath = value; 1A G<$d5U|  
} $ig0j`  
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public String getSFileName() hp7|m0.JW  
{ ?6un4EVL{  
return sFileName; UK O[r;  
} ^!ZC?h!rG  
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public void setSFileName(String value) ERE)A-8  
{ ^
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sFileName = value; TNY&asQo  
} GyIT{M}KV  
*|C^=*j9  
xLWwYK  
public int getNSplitter() $oU*9}}Rn  
{ b TM{l.Aq3  
return nSplitter; %GA"GYL9'  
} evAMJ=  
-
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#_J@-f7^  
public void setNSplitter(int nCount) pg.ri64H<  
{ UT=tT)4b  
nSplitter = nCount; F{Jw^\  
} NOiN^::m  
} ,p2s:&"  
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/* f~y%%+{p  
**Utility.java >x+6{^}Q>  
*/ o` ZQd,3  
package NetFox; Avd ^  
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public class Utility { r1.nTO%  
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public Utility() %g$V\zmU  
{ /VS[pXXT|  
,dov<U[ia  
(-xS?8x$  
} Gh}LlX!w  
Y*>#T  
//线程睡眠 7;sj%U^'l  
public static void sleep(int nSecond) bRJMYs  
{ 1+qw$T  
try{ t2"O  
Thread.sleep(nSecond); qnJt5  
} ?NR A:t(}  
catch(Exception e) wF,UE_  
{ iH@yCNE"
 
e.printStackTrace (); VsgE!/>1  
} qY<'<T4\  
} ujaGNg?,  
!2A:"2Kys:  
//日志 +!z{5:  
public static void log(String sMsg) RIXMJ7e7  
{ RHq/JD-  
System.err.println(sMsg); Z!@~>i  
} *-q"3D`  
Nq` C.&  
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public static void log(int sMsg) xA1hfe.9  
{ WZ7BoDa7O  
System.err.println(sMsg); KgOqbSJ  
} Mjfx~I27  
} ~Ro9up  
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/* YW

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**TestMethod.java (TwnkXrR,  
*/ "@d[h,TM  
package NetFox; 3k#/{Z  
}YMy6eW4  
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public class TestMethod { y[\VUzD*'  
m&\h4$[kql  
l>{R`BZ/  
public TestMethod() +~roU{& o  
{ ///xx/weblogic60b2_win.exe ?~;:jz|9<'  
try{ ]dk8lZ;bo  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YZ7|K<   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8` @G;o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M^iU;vo  
fileFetch.start(); RIE5KCrGB  
} h0-hT   
catch(Exception e){e.printStackTrace ();} Zh*u(rO  
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} Nwt" \3  
Bj}^\Pc;}  
{>,V\J0p  
public static void main(String[] args) + 33@?fl.  
{ %Gj8F4{  
new TestMethod(); '|*?*
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} Yd=a}T  
} 9^Whg~{  
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