http断点续传简单实现（java)

/* =wG+Ao  
**SiteFileFetch.java H6K`\8/SeN  
*/ paW@\1Q  
package NetFox; :=Kx/E:1  
import java.io.*; =Q<L eh=G  
import java.net.*; 5|I55CTx  
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public class SiteFileFetch extends Thread { C3XmK}h  
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SiteInfoBean siteInfoBean = null; //文件信息Bean >Kivuc  
long[] nStartPos; //开始位置 =8Ehrlq
 
long[] nEndPos; //结束位置 }tG3tz0%fX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2&Jdf  
long nFileLength; //文件长度 nwA8ALhE  
boolean bFirst = true; //是否第一次取文件 hePPxKQ-  
boolean bStop = false; //停止标志 ^e Gue  
File tmpFile; //文件下载的临时信息 jZpa0grA  
DataOutputStream output; //输出到文件的输出流 FS"eM"z  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） x%N\5 V1  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~rD={&0  
{ 8X$LC  
siteInfoBean = bean; k|YWOy@D~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); nV*y`.+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9Q;c,]  
if(tmpFile.exists ()) .]x2K-Sf  
{  k5`OH8G  
bFirst = false; 
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read_nPos(); '?QuJFki  
} ;eL9{eF  
else "*z_O  
{ |Ic`,>XM  
nStartPos = new long[bean.getNSplitter()]; | ?yo 3  
nEndPos = new long[bean.getNSplitter()]; jS.g]k  
}  \ %=9  
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} "O[j!fG8,  
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public void run() ? "/ fPV-  
{ nH|,T%  
//获得文件长度 kS# CEU7  
//分割文件 bzN-*3YE=  
//实例FileSplitterFetch w|[RDaAb  
//启动FileSplitterFetch线程 ^].jH+7i*  
//等待子线程返回 S=`+Ryc  
try{ Sh6JF574T  
if(bFirst) +pm[f["C.  
{ I6!5Yj]O"  
nFileLength = getFileSize(); 8eBOr9l+j  
if(nFileLength == -1) V/d/L3p  
{ }x0- V8  
System.err.println("File Length is not known!"); }n_p$g[Nj/  
} ;Q;[*B=kE  
else if(nFileLength == -2) l_tw<`Ep  
{ epHJ@W@#  
System.err.println("File is not access!"); ulFzZHJ  
} wXMDh$  
else @Ky> 9m{  
{ '*^yAlgtt  
for(int i=0;i<nStartPos.length;i++) l_'[27
 
{ N==ZtKj F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /cr}N%HZB  
} :~Q!SL N  
for(int i=0;i<nEndPos.length-1;i++) }R[#?ty;]  
{ uMb>xxf  
nEndPos = nStartPos[i+1]; WEg6Kz  
} m([(:.X/IX  
nEndPos[nEndPos.length-1] = nFileLength; "\W-f  
} =J-5.0Q\_\  
} 6lwta`2  
]uj=:@  
kd`0E-QU  
//启动子线程 D_mL,w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }v9\F-0>Q  
for(int i=0;i<nStartPos.length;i++) 7;@ST`cC  
{ DZ7 gcC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
}?F`t[+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $ ,SF@BhO  
nStartPos,nEndPos,i); {GDmVWG0q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~\)qi=  
fileSplitterFetch.start(); :F,O  
} FWue;pw3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SzwQOs*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W7"{r)7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Zv11uH-C  
nEndPos = " + nFileLength); `\`>0hlu  
// fileSplitterFetch[nPos.length-1].start(); *L6PLe  
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//等待子线程结束 T{qTj6I  
//int count = 0; w=]Ks'C]  
//是否结束while循环 %W,D;?lEo>  
boolean breakWhile = false; <~TP#uAz  
pLa[}=  
'{I_\~*  
while(!bStop) XC 7?VE  
{ TD[EQ  
write_nPos(); %*aJLn+]_R  
Utility.sleep(500); ^,l_{  
breakWhile = true; 9)xUA;Qw?z  
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for(int i=0;i<nStartPos.length;i++) NNhL*C[_7  
{ Xs&TJ8a  
if(!fileSplitterFetch.bDownOver) uw\2qU3g
k  
{ V.ht, ~l  
breakWhile = false; @`tXKP$so  
break; >Vy>O&r  
} 21s4MagC  
} dzK{ Z  
if(breakWhile) `l2O?U-@  
break; aQ^umrj@?9  
)"f N!9,F  
4'$g(+z  
//count++; C%*k.$#r!  
//if(count>4) Mb3}7@/[  
// siteStop(); 5aad$f  
} .=m,hu~  
1im^17X  
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System.err.println("文件下载结束！"); l4n)#?Q?  
} 8+]hpa,q  
catch(Exception e){e.printStackTrace ();} y;mj^/SxK  
} lo%;aK  
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iz
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//获得文件长度 G} eUL|S  
public long getFileSize() DD" $1o"  
{ ??TMSH  
int nFileLength = -1; QL6C,#6  
try{ LjL[V'JL  
URL url = new URL(siteInfoBean.getSSiteURL()); f.24:Dw,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {`2R,Jb%S  
httpConnection.setRequestProperty("User-Agent","NetFox"); E?(xb B  
o=FE5"t  
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int responseCode=httpConnection.getResponseCode(); #%J5\+ua  
if(responseCode>=400) $+.l*]  
{ l3N I$Zu  
processErrorCode(responseCode); $/6;9d^  
return -2; //-2 represent access is error 2[0JO.K 4  
} *:i1Lv@  
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String sHeader; u77E! z4Uz  
vI$t+m:  
s1|/S\
  
for(int i=1;;i++) q+B&orp  
{ s@MYc@k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ==i[w|  
//Utility.log(in.readLine()); XqM3<~$  
sHeader=httpConnection.getHeaderFieldKey(i); PtqJ*Z  
if(sHeader!=null) @EE."T9  
{ Sa19q.~%  
if(sHeader.equals("Content-Length")) olLfko4$*V  
{ qY\f'K}Q*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -v6M<  
break; x `V;Y]7'  
} n$xQ[4eH)  
} '`1CBU$  
else (98Nzgxgx}  
break; 42>Ge>#F  
} Qt]Q:9I[  
} s=?g\oR  
catch(IOException e){e.printStackTrace ();} 8kP3+  
catch(Exception e){e.printStackTrace ();} NEa>\K<\  
r>bJ%M}  
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Utility.log(nFileLength); '+j} >Q  
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return nFileLength; ;S xFp  
} VLBE'3Qg1  
5k|9gICyd*  
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//保存下载信息（文件指针位置） t>8XTqqi  
private void write_nPos() Scv#zuv_  
{ iAa;6mH  
try{ "`6n6r42  
output = new DataOutputStream(new FileOutputStream(tmpFile)); AkOO)0  
output.writeInt(nStartPos.length); \.
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for(int i=0;i<nStartPos.length;i++) $%VuSrZ&  
{ Qp`gswvE  
// output.writeLong(nPos); U-n;xX0=  
output.writeLong(fileSplitterFetch.nStartPos); 0ZQ'_g|%  
output.writeLong(fileSplitterFetch.nEndPos); ccd8O{G.M  
} 1:Si,d,wh  
output.close(); /c):}PJ^#7  
} 4Jx"A\5*G  
catch(IOException e){e.printStackTrace ();} G\NPV
'  
catch(Exception e){e.printStackTrace ();} 
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}
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wcDRH)AW.  
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//读取保存的下载信息（文件指针位置） u{["50~  
private void read_nPos() B c2p(z4  
{ >vo=]cw  
try{ l7
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Fd*8N8Pi  
int nCount = input.readInt(); :x_'i_w  
nStartPos = new long[nCount]; {}:ToIp  
nEndPos = new long[nCount]; O{ /q-~_  
for(int i=0;i<nStartPos.length;i++) <T[E=#  
{ F[
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nStartPos = input.readLong(); NWxUn.Gy9  
nEndPos = input.readLong(); OT&k.!=  
} Y2'cs~~$Ce  
input.close(); Ali9pvE  
} y!]CJigpZ  
catch(IOException e){e.printStackTrace ();} ExRe:^yU\  
catch(Exception e){e.printStackTrace ();} 7 I>G{  
} epg
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)& u5IA(  
private void processErrorCode(int nErrorCode) ?.Pg\ur  
{ =/\:>+p^.y  
System.err.println("Error Code : " + nErrorCode); aM4k *|H?  
} XV^1tX>f{  
n("0%@ov  
KF4PJi;*  
//停止文件下载 ^wS5>lf7p  
public void siteStop() Is+O  
{ |*`Z*6n  
bStop = true; 0?>dCu\  
for(int i=0;i<nStartPos.length;i++) c&L"N!4z  
fileSplitterFetch.splitterStop(); d:yqj:  
;j2vHU#q-  
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} kY'T{Sm1^  
} LiKxq=K  
//负责部分文件的抓取 `mN4_\]  
**FileSplitterFetch.java "*})3['n  
*/ rb{P :MX  
package NetFox; |hr]>P1  
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import java.io.*; *YlV-C<}W"  
import java.net.*; VsA'de!V4[  
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public class FileSplitterFetch extends Thread { ^i:B+ rl  
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String sURL; //File URL a5w:u5  
long nStartPos; //File Snippet Start Position ":_vK}5  
long nEndPos; //File Snippet End Position 2=_gf  
int nThreadID; //Thread's ID f47M#UC  
boolean bDownOver = false; //Downing is over $HJwb-I  
boolean bStop = false; //Stop identical R"K#7{p9  
FileAccessI fileAccessI = null; //File Access interface f^VP/rdg  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException im @h -A]0  
{ +5XpzZ{#Wa  
this.sURL = sURL; /B}lO0]:  
this.nStartPos = nStart; ~9j%Hm0ht  
this.nEndPos = nEnd; ?@V[#.  
nThreadID = id; FHV-BuH5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E4hLtc^ +
 
} 5<w g8y  
9*a=iL*Nw  
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public void run() R
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{ p QizJ6  
while(nStartPos < nEndPos && !bStop) o*J3C>  
{ )wNP( @$L  
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){UcS/GI=  
try{ &-;5* lg)0  
URL url = new URL(sURL); .?l\g-;=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :>=\.\  
httpConnection.setRequestProperty("User-Agent","NetFox"); sM9+dh  
String sProperty = "bytes="+nStartPos+"-"; ^`G}gWBx}w  
httpConnection.setRequestProperty("RANGE",sProperty); f;b[w

 
Utility.log(sProperty); ,N0#!<}4  
/i77  
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InputStream input = httpConnection.getInputStream(); g1(IR)U!z  
//logResponseHead(httpConnection); /E\%>wv  
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byte[] b = new byte[1024]; 7a~X:#  
int nRead; Hhh0T>gi  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) KRA/MQ^7~U  
{ BT(CM,bp  
nStartPos += fileAccessI.write(b,0,nRead); rOVVL%@QqJ  
//if(nThreadID == 1) [1u-Q%?#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ih"XV  
} cCxBzkH6  
p3^m9J  
,S!azN=  
Utility.log("Thread " + nThreadID + " is over!"); }+sT4'Ah>  
bDownOver = true; F|!){=   
//nPos = fileAccessI.write (b,0,nRead); 1@-Ns  
} \P6$mh\T  
catch(Exception e){e.printStackTrace ();} L+i(TM=  
} ?F3h)(}  
} G nG>7f[v  
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aca=yDs2  
//打印回应的头信息 &Udb9  
public void logResponseHead(HttpURLConnection con) a0#J9O_  
{ (I./ Uu%  
for(int i=1;;i++) }1upi=+aE  
{ 1aTB%F  
String header=con.getHeaderFieldKey(i); (UxW;  
if(header!=null) _FWBUZ;N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); U-3i  
Utility.log(header+" : "+con.getHeaderField(header)); .Fp4: e  
else &mx)~J^m  
break; Bf8jPa/  
} v%iflCK  
} \:UIc*S  
~W-PD  
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public void splitterStop() ~ (jKz}'~U  
{ MpR2]k#n<  
bStop = true; HKUn`ng  
} b"{'T]"*j  
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#n8IZ3+
  
} &*aIEa^  
6g)GY"49  
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/* V]db'qB\  
**FileAccess.java VB*oGG  
*//文件访问(定位，写) 2V#>)R#k  
package NetFox; 6l
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import java.io.*; Ob<{G"  
:Nz2z[W$  
mUikA9u5=  
public class FileAccessI implements Serializable{ OD!
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c$yk s  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CTZ8Da^  
RandomAccessFile oSavedFile; O*FUTZd(J  
long nPos; 7x%R:^*4  
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public FileAccessI() throws IOException :BV6y|J9O^  
{ m3/O.DY%0  
this("",0); [UWdW  
} 9j6QX~,  
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public FileAccessI(String sName,long nPos) throws IOException <"my^  
{ R[hzMU}KB  
oSavedFile = new RandomAccessFile(sName,"rw"); 4J/}]Dr5  
this.nPos = nPos; 4?q
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oSavedFile.seek(nPos); >]vlkA(  
} 2OVRf0.R~  
)x=1]T>v"'  
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public synchronized int write(byte[] b,int nStart,int nLen) Eu@huN*/  
{ Oagsoik  
int n = -1; .Z `av n  
try{ x#xFh0CA  
oSavedFile.write(b,nStart,nLen); :Ra,Eu  
n = nLen; =*c7i]@}  
} .7avpOfz  
catch(IOException e) A#J`;5!Sc  
{ >8#X;0\Kj  
e.printStackTrace (); SPY|K  
} Ssou  
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return n; 9\mLW"  
} &&8IU;J  
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} 8h*Icf  
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/* /)}
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**SiteInfoBean.java PuA9X[=  
*/ K1+)4!}%U  
package NetFox; BMG3|N^  
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public class SiteInfoBean { DN-+o
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private String sSiteURL; //Site's URL Rnr(g;2  
private String sFilePath; //Saved File's Path Q/(K$6]j  
private String sFileName; //Saved File's Name 5A3xVN=  
private int nSplitter; //Count of Splited Downloading File 26I_YL,S  
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c|B.n]Z  
public SiteInfoBean() [ 0KlC1=  
{//nSplitter的缺省值为5 xy/`ZS2WPq  
//default value of nSplitter is 5 {E9+WFz5  
this("","","",5); mpU$+  
} ,*&:2o_r  
(3Two}  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1Z+8r  
{ t4zkt!`B  
sSiteURL= sURL; Eg#K.5hJ  
sFilePath = sPath; jHE}qE~>5  
sFileName = sName; i@)i$i4
  
this.nSplitter = nSpiltter; 75f"'nJ)  
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-pf}  
} 59Xi3KY  
s E2D#D  
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public String getSSiteURL() mS$j?>m  
{ tl,.fjZn  
return sSiteURL; A@1W}8qY:  
} bLij7K2H  
7Bzq,2s
 
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public void setSSiteURL(String value) v&Yi  
{ Ai=se2  
sSiteURL = value; Pq;U&,  
} )wam8k5  
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public String getSFilePath() `scR*]f1+  
{ #~}nFY.  
return sFilePath; Wuc S:8#|  
} ZM!CaR  
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public void setSFilePath(String value) LtWP0@JA  
{ S;3R S;  
sFilePath = value; /YP{,#p  
} sJ;g$TB  
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public String getSFileName() s C%&cRQD  
{ 42_`+Vt]d7  
return sFileName; ;f0I 8i,JN  
} "pi=$/RD9  
X$ 0?j1  
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public void setSFileName(String value) 5nv#+ap1 "  
{ C%$edEi  
sFileName = value; [')m|u~FS4  
} "CSsCA$/  
#^lL5=  
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public int getNSplitter() h58`XH  
{ Zd^rNHhA  
return nSplitter; ,&]S(|2%>t  
} 3}TaF~  
y I HXg#  
AK,J7
 
public void setNSplitter(int nCount) 4IB9,?p  
{ p `8s  
nSplitter = nCount; 0bceI  
} gn8R[5:!V  
} 8'r2D+Vwm  
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/* rn/ /%  
**Utility.java <r.)hT"0  
*/ bR*-Ht+wd  
package NetFox; l
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*g:4e3Iy  
public class Utility { Fsmycr!R  
E ]A#Uy  
>BR(Wd.  
public Utility() oX#Q<2z*  
{ =)M/@T  
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} 5A)2} D]  
=e/9&993  
//线程睡眠 WZ-s--n#  
public static void sleep(int nSecond) 0t^M3+nc  
{ ?J%1#1L"/  
try{ B-?6M6#  
Thread.sleep(nSecond); yCd-9zb=  
} *rM^;4Zt  
catch(Exception e) <;9I@VYK  
{ 0Iw
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e.printStackTrace (); :#LLo}LKp  
} T%.8'9  
} %824Cqdc  
iqC|G/  
//日志 _7Rr=_1}  
public static void log(String sMsg) Ff$L|  
{  AsQ)q  
System.err.println(sMsg); ~+Rc}K  
} R+2+-j4  
fV &KM*W*@  
*"+=K,#D  
public static void log(int sMsg) 3AHlSX  
{ l Q'I  
System.err.println(sMsg); Pj#<K%Bz  
} Gy9$wH@8  
} ]mo-rhDsM  
eK6hS_E  
Fz3fwLawI  
/* 6%'.A]"  
**TestMethod.java 8UW^"4  
*/ V@B__`y7  
package NetFox; -|J"s$yO4  
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nim*/LC[:  
public class TestMethod { 3p39`"~  
@KWb+?_H{<  
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public TestMethod() 9E
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{ ///xx/weblogic60b2_win.exe 3/aMJR:o  
try{ *EOdEFsR/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
GQt8p[!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %=n!Em(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `Bo*{}E  
fileFetch.start(); 33o9Yg|J~  
} \.C+ue  
catch(Exception e){e.printStackTrace ();} TlXI|3Ip  
B:
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} ^"VJd[Hn  
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public static void main(String[] args) "w^!/  
{ #D<C )Q  
new TestMethod(); yyoqX"v[  
} nc~F_i=  
} s:OFVlC%\  
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