http断点续传简单实现（java)

/* WXRHG)nvL  
**SiteFileFetch.java  m,xy4  
*/ *S,v$ VX  
package NetFox; ,S7~=S  
import java.io.*; x)%% 5  
import java.net.*; ghE?8&@ iq  
k4]R]=Fh.  
F&>T-u-dog  
public class SiteFileFetch extends Thread { KzxW?Ji$S  
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rjhs?  
SiteInfoBean siteInfoBean = null; //文件信息Bean 9F-ViDI.  
long[] nStartPos; //开始位置 HCfS)`  
long[] nEndPos; //结束位置 9}?
 5p]%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UEx(~>  
long nFileLength; //文件长度 :8p2Jxm  
boolean bFirst = true; //是否第一次取文件 #khyy-B=  
boolean bStop = false; //停止标志 Y)@oo=oG  
File tmpFile; //文件下载的临时信息 =[v2
 
DataOutputStream output; //输出到文件的输出流 znGZULa#  
~2;&pZ$  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,.1&Ff
)S  
public SiteFileFetch(SiteInfoBean bean) throws IOException S5YDS|K  
{ ]JhDRJ\  
siteInfoBean = bean; 7%~VOB  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Q{(,/}kA-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ae,2Xi  
if(tmpFile.exists ()) kM6 EZ`mj  
{ SF78s:_!_  
bFirst = false; :BC<+T=  
read_nPos(); "!w[U{  
} -wG[>Y  
else ^mQ;CMV  
{ 4#'^\5  
nStartPos = new long[bean.getNSplitter()]; r!-L`
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nEndPos = new long[bean.getNSplitter()]; 'Sb6 w+  
} 7.F& {:@_  
}(f,~?CP]  
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} o} bj!h]N  
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public void run() @et3}-c  
{ x1 R!  
//获得文件长度 :&\E\9  
//分割文件 tCF0Ah  
//实例FileSplitterFetch $bM#\2'  
//启动FileSplitterFetch线程 ta+"lM7A}$  
//等待子线程返回 L?/M2zc9Y  
try{ &Pn%zfmMN  
if(bFirst) ?U2g8D nFY  
{ ~Krg8s!F&  
nFileLength = getFileSize(); ]h`E4B  
if(nFileLength == -1) .DM1Knj  
{ ~-o^eI4_  
System.err.println("File Length is not known!"); SOi(5]  
} ]#WX|0''^  
else if(nFileLength == -2) Hme@9(zD.  
{ s$3eJ|  
System.err.println("File is not access!"); $`+~QR!h  
} #L
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else 6:7:NIl:  
{ h&^/, G  
for(int i=0;i<nStartPos.length;i++) k6 h^  
{ A16-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); o*5e14W(:  
} R}K5'`[%ZY  
for(int i=0;i<nEndPos.length-1;i++) G~mB=]  
{ _dRn0<#1(k  
nEndPos = nStartPos[i+1]; Lqf#,J  
} 85d7IB{28  
nEndPos[nEndPos.length-1] = nFileLength; pCud` :o"  
} QKuc21  
} eyl) uR  
[^"(%{H  
3M>FU4Ug2  
//启动子线程 pdXgr)Uv  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !WVabdt  
for(int i=0;i<nStartPos.length;i++) J*W;{Vty  
{ `HZHVV$~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hdNZ":1s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pC?1gc1G  
nStartPos,nEndPos,i); V'BZ=.=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^.$r1/U  
fileSplitterFetch.start(); p%YvP  
} }E\+e!'!2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5qAE9G!c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
tg%WVy2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", My43\p  
nEndPos = " + nFileLength); @
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// fileSplitterFetch[nPos.length-1].start(); &,gryBN  
+cp
lM5X  
9zGKQ|X)  
//等待子线程结束 myo~Qqt?  
//int count = 0; QIxJFr;>  
//是否结束while循环 2ShlYW@~  
boolean breakWhile = false; ~bm2_/RL  
$>*/']>  
N*4IxY'vX/  
while(!bStop) uq1(yyWp(  
{ G^eFS;  
write_nPos(); ThiPT|5u  
Utility.sleep(500); 9p0HFri[  
breakWhile = true; 7^Q$pT>  
R~mMGz  
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for(int i=0;i<nStartPos.length;i++) _xZb;PbFE  
{ 0kr& c;~  
if(!fileSplitterFetch.bDownOver) Wa
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{ J$=b&$I(  
breakWhile = false; SoON@h/  
break; yl;$#aZB  
} mjr{L{H=?+  
} Vm%ux>}  
if(breakWhile) sOtNd({  
break; BtBt>r(*  
]KV8u1H>  
TKs@?Q,J  
//count++; rgY?X$1q_  
//if(count>4) @42lpreT  
// siteStop(); }n&JZ`8<s  
} 1*`JcUn,>  
#z54/T  
KcyM2hE7  
System.err.println("文件下载结束！"); u$`x]K=Zsm  
} RgzSaP;;  
catch(Exception e){e.printStackTrace ();} 2|H'j~  
} 8X~vJ^X9@y  
5r}(|86O/  

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//获得文件长度 L\'qAfRZ  
public long getFileSize() VH1c)FI  
{ O%h 97^%k  
int nFileLength = -1; w+TuS).  
try{ T/.y(8!0I8  
URL url = new URL(siteInfoBean.getSSiteURL()); ra#)*fG,~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RBojT   
httpConnection.setRequestProperty("User-Agent","NetFox"); vBQ?S2f  
yDBgSO{d  
{_gj>n(1  
int responseCode=httpConnection.getResponseCode(); G5@fqh6ws  
if(responseCode>=400) T%vbD*nt.  
{ Fm+)mmJP  
processErrorCode(responseCode); 'C4Ll2  
return -2; //-2 represent access is error U=?"j-wN  
} $">NW& i(  
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String sHeader; 38S&7>0@|q  
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,rPyXS9Sa{  
for(int i=1;;i++) Dve5m=  
{ -Ce4px?3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @z?.P;f9#  
//Utility.log(in.readLine()); R$,iDv.jI  
sHeader=httpConnection.getHeaderFieldKey(i); @V CQ4X7T  
if(sHeader!=null) ^)]*10  
{ }K]VlFR  
if(sHeader.equals("Content-Length")) i'LTKj  
{ [ESs?v$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); e
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break; +s 0
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} %l P   
} uWT&`m_(2  
else |*| a~t  
break; ':>*=&  
} 1s\hJATfz  
} ^\9G{}VY  
catch(IOException e){e.printStackTrace ();} . zMM86c  
catch(Exception e){e.printStackTrace ();} t#{>y1[29  
!d@`r1t  
)/^$J
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Utility.log(nFileLength); H%gD[!^  
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return nFileLength; ]xeyXw84k  
} V zx(J)  
&_^<B7aC'k  
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//保存下载信息（文件指针位置） FPFYH?;$  
private void write_nPos() { qx,X.5$  
{ eBKIdR%k  
try{ vrDRSc6_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); < tq9  
output.writeInt(nStartPos.length); -k{R<L  
for(int i=0;i<nStartPos.length;i++) W5uI(rS<6  
{ DfFPGFv  
// output.writeLong(nPos); ]>i0;RME  
output.writeLong(fileSplitterFetch.nStartPos); />7/S^  
output.writeLong(fileSplitterFetch.nEndPos); 2= mD  
} vw6FvE`lC  
output.close(); muq|^Hfb  
} #9"_|d=l  
catch(IOException e){e.printStackTrace ();} nx]b\A  
catch(Exception e){e.printStackTrace ();} R?Q-@N>wE  
} ?LFSR  
G{Q'N04
RA  
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//读取保存的下载信息（文件指针位置） mR@X
t#  
private void read_nPos() o/ 5Fg>d  
{ ZEJadR  
try{ D/`E!6Fk=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); VMXXBa&  
int nCount = input.readInt(); pa73`Ca]  
nStartPos = new long[nCount]; x)5v8kgf  
nEndPos = new long[nCount]; H)+kN'J  
for(int i=0;i<nStartPos.length;i++) m%\[1|N  
{ JOq<lb=  
nStartPos = input.readLong(); Q^Z}Y~.  
nEndPos = input.readLong(); [SvwJIJJ  
} !AHm+C_=Lg  
input.close(); _q$fw&  
} `roSOX1f  
catch(IOException e){e.printStackTrace ();} O{R5<"g  
catch(Exception e){e.printStackTrace ();} jG :R\D}0  
} FI5C&d5d  
}O{"qs#)  
PSE|4{'  
private void processErrorCode(int nErrorCode) *xC '  
{ 'E,Yht=/}  
System.err.println("Error Code : " + nErrorCode); hj1jY  
} :W.(,65c  
0E[Se|!  
4et#Q  
//停止文件下载 qZ}XjL  
public void siteStop() N|LVLsK  
{ 0/]vmDr  
bStop = true; ".ZiR7Z:$Y  
for(int i=0;i<nStartPos.length;i++) uoHhp4>^  
fileSplitterFetch.splitterStop(); QD~`UJe>  
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c y$$}  
} r&DK> H  
} |i8dI)b  
//负责部分文件的抓取 \&90$>h  
**FileSplitterFetch.java %"2B1^o>
 
*/ lhTbgM  
package NetFox; 4UkLvL1x  
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?Sxnq#r#  
import java.io.*; 6f>HE'N  
import java.net.*; XQ+hTtP  
-9"Ls?Cu  
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_  
public class FileSplitterFetch extends Thread { Us5JnP5  
sSK$  
N~d]}J8}gx  
String sURL; //File URL P|U>(9;P,  
long nStartPos; //File Snippet Start Position ]0le=Ee^%  
long nEndPos; //File Snippet End Position +s}28U!  
int nThreadID; //Thread's ID E>D@#I>  
boolean bDownOver = false; //Downing is over ZZ5yu* &  
boolean bStop = false; //Stop identical 78-:hk  
FileAccessI fileAccessI = null; //File Access interface quYZD6IH  
tPHiz%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~s_$a8  
{ Y<XDR:]A,  
this.sURL = sURL; |93%,  
this.nStartPos = nStart; gjV&X N  
this.nEndPos = nEnd; 91XHz14  
nThreadID = id; '5--eYG  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Vp$ckr  
} -(G2@NG  
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/H%pOL6(r  
public void run() K~>kruO";  
{ kuaov3Ui  
while(nStartPos < nEndPos && !bStop) =Yk$Q\c
 
{
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try{ fZO/HzX  
URL url = new URL(sURL); *79<ypKG$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `h'^S,'*  
httpConnection.setRequestProperty("User-Agent","NetFox");
:O%O``xT  
String sProperty = "bytes="+nStartPos+"-"; 8Bvjj|~ (@  
httpConnection.setRequestProperty("RANGE",sProperty); 10&A3C(E  
Utility.log(sProperty); m.*+0NG  
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InputStream input = httpConnection.getInputStream(); .YkKIei  
//logResponseHead(httpConnection); 5\J;EWTU  
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voxlo>:  
byte[] b = new byte[1024]; #a&Vx&7L  
int nRead; +!(hd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I"1\R8 R  
{ q.7CPm+  
nStartPos += fileAccessI.write(b,0,nRead); 2h!3[{M\  
//if(nThreadID == 1) ?H`LrL/k  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V1G]LM  
} N\?iU8w=  
Y>+D\|%
Q  
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Utility.log("Thread " + nThreadID + " is over!"); )".gjW8{#L  
bDownOver = true; 4\?B,!  
//nPos = fileAccessI.write (b,0,nRead); h(sD]N  
} cPXvTVvs  
catch(Exception e){e.printStackTrace ();} J
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} (ni$wjq=z^  
} slx^" BF^  
u=[oo@Rk`  
(2(hl--'n  
//打印回应的头信息 h:;~)={"X  
public void logResponseHead(HttpURLConnection con) Ub$$wOsf  
{ h4#5j'
RO  
for(int i=1;;i++) `6A"eDa  
{ -*EJj>x  
String header=con.getHeaderFieldKey(i); 1\p
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if(header!=null) zSO[f  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ZS-9|EA<  
Utility.log(header+" : "+con.getHeaderField(header)); |&JL6hN  
else L0Cf@~k  
break; /iK )tl|X  
} ZttL*KK  
} _W+TZa@_  
rW^&8E[  
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public void splitterStop() 4)ISRR  
{  ,Y!)V  
bStop = true; 'K1w.hC<  
} =aCv Xa&,  
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} -=RXhE_{  
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/* gLH(Wr~(a  
**FileAccess.java NJp;t[v.^  
*//文件访问(定位，写) FueJe/~t  
package NetFox; =pNkS
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import java.io.*; r\]WDX!`  
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public class FileAccessI implements Serializable{ J L3A/^  
,P|PP
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V)`?J)  
RandomAccessFile oSavedFile; _#_Ab8#  
long nPos; cZYX[.oIB  

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X[
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public FileAccessI() throws IOException $lqV(s  
{ QUNsS9  
this("",0); Nl+2m4  
} <L-L}\-I"  
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public FileAccessI(String sName,long nPos) throws IOException Q,$x6YwE  
{ ;i]cmy  
oSavedFile = new RandomAccessFile(sName,"rw"); R Q8okA  
this.nPos = nPos; 5s>9v  
oSavedFile.seek(nPos); /~yqZD<O  
} &jJgAZ!  
q\,H9/.0k  
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public synchronized int write(byte[] b,int nStart,int nLen) 5HU>o|.  
{ "*
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int n = -1; $=bN=hE  
try{ pUmB h  
oSavedFile.write(b,nStart,nLen); yE7pCgXt  
n = nLen; ZoUfQ!2*  
} l|K8+5L  
catch(IOException e) |J\/U,n
h  
{ B}(YD;7vJ  
e.printStackTrace (); FD*y[A ?  
} >Cf`F{X'U  
Jx}5`{\  
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return n; mVkn~LD:0  
} |qr[*c3$1  
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} Wp'\NFe8  
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/* YPM>FDxDB  
**SiteInfoBean.java TKE)NIa  
*/ 2
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package NetFox; p+t8*lkq  
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i~2>kxf;K1  
public class SiteInfoBean { Li'T{0)1)  
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private String sSiteURL; //Site's URL !y),| #7P  
private String sFilePath; //Saved File's Path %:y-"m1\u$  
private String sFileName; //Saved File's Name NE! Xt<A  
private int nSplitter; //Count of Splited Downloading File +)Ty^;+[1  
YT_kMy>  
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public SiteInfoBean() 2vXMrh\  
{//nSplitter的缺省值为5 3.jwOFH$  
//default value of nSplitter is 5 LDNp
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this("","","",5); OYKV*  
} ]}B&-Yp  
D(&OyZ~Q+  
j)uIe)wZw  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B|Omz:c  
{ jfWIPN  
sSiteURL= sURL; pZR^ HOq  
sFilePath = sPath; }'{(rU  
sFileName = sName; |QY+vO7fxj  
this.nSplitter = nSpiltter; &M2x`  
/i"EVN`t  
sq^,l6es>  
} A@#dv2JzP  
0'~?u'  
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public String getSSiteURL() Dn@ n:m  
{ VcP#/&B|  
return sSiteURL;
U` U/|@6  
} QZ`<+"a0  
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E  
5 9X|l&/  
public void setSSiteURL(String value) -L
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{ jPd<h{js  
sSiteURL = value; pQ>V]M  
} m/ukH{H1%  
c
{<3\  
"~;jFB8  
public String getSFilePath() r[lHYO  
{ GwvxX&P  
return sFilePath; L{=z}QO  
} P~#jvm!  
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qq/Cn4fN8  
public void setSFilePath(String value) 1Tl("XV3
 
{ MVCCh+,GI  
sFilePath = value; C+iP @~  
} 9GEcs(A*  
`+gF|o9  
4e(@b3y  
public String getSFileName() Uag1vW,c  
{ oacY-&  
return sFileName; F7hQNQu:  
} 0uvL,hF  
sPw(+m*C   
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public void setSFileName(String value) Ns $PS\  
{ LY>JE6zTt  
sFileName = value; /t/q$X  
} E,X,RM~ +D  
p-}:7CXP  
4S=lO?\"A  
public int getNSplitter() iaC$K@a{  
{ }a`LOBne  
return nSplitter; '-x%?Ll  
} J0oR]eT}  
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+2g3%c0}  
public void setNSplitter(int nCount) zPXd]jIwV  
{ :JS}(  
nSplitter = nCount; ^Nu} HcC+  
} (UM+?]Qwy  
} #i,O "`4  
Jq!($PdA  
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/* HlO+^(eX  
**Utility.java Ju\"l8[f  
*/ p
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package NetFox; )ad-s  
w7C=R8^  
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public class Utility { IIPf5 Z}A  
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public Utility() ,i|f8pZ  
{ e,BJD>N ?  
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;CW$/^QNr5  
} 3)ip@29F  
|j+~Td3})&  
//线程睡眠 ieI-_]|[  
public static void sleep(int nSecond) H~@h #6  
{ YszhoHYh  
try{ :Ls36E8f=  
Thread.sleep(nSecond); BpCSf.zZ  
} 5J;c;PF  
catch(Exception e) 'UyL%h;nJ  
{ 3LmHH =  
e.printStackTrace (); oMPQkj;  
} +R_U  
} X}yYBf/R`  

\5Jv;gc\\  
//日志 p.HA`R>  
public static void log(String sMsg) `#ztp)&  
{ ~IXfID!8  
System.err.println(sMsg); jt3SA [cy  
} x#^kv)  
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public static void log(int sMsg) )&9RoW()?  
{ #59zv=  
System.err.println(sMsg); j;3o9!.s:  
} hD*?\bBs0  
} D.!4i.)8}  
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/* N9Ml&*%oX{  
**TestMethod.java [h1{{Nb#ez  
*/ sF$m?/Kt  
package NetFox; D4\I;M^  
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public class TestMethod { ^kq!/c3r  
R4/@dA0  
<'-me09C*  
public TestMethod() FuKNH~MevQ  
{ ///xx/weblogic60b2_win.exe _X[c19q  
try{ <fJ\AP5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); vpDs5tUl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); hG^23FiN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X&IY(CX  
fileFetch.start(); 2?j1~]DvZ  
} ,3j7Y5v  
catch(Exception e){e.printStackTrace ();} %?fzT+-=%  
( ~>Q2DS  
T!PX?  
} msylb~^  
J^:~#`8  
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public static void main(String[] args) m5Kx}H~  
{ Mx"tUoU6z  
new TestMethod(); MF`'r#@:wa  
} yKJ^hv"#  
} N,|oV|i  
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