http断点续传简单实现（java)

/* ,puoq{  
**SiteFileFetch.java %+=;4tHJ  
*/ -R]0cefC<f  
package NetFox; Bd <0}  
import java.io.*; P*A+k"DU1  
import java.net.*; Yu\$Y0 {]  
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public class SiteFileFetch extends Thread { s`_EkFw>Gl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {#qUZ z-  
long[] nStartPos; //开始位置 dazNwn  
long[] nEndPos; //结束位置 LNWS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "t&=~eOe3  
long nFileLength; //文件长度 j*<J&/luYZ  
boolean bFirst = true; //是否第一次取文件 <7VLUk}  
boolean bStop = false; //停止标志 xeSch?}  
File tmpFile; //文件下载的临时信息 W|m(Jh[w]  
DataOutputStream output; //输出到文件的输出流 46}U+>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） } +}nrJv  
public SiteFileFetch(SiteInfoBean bean) throws IOException hm1s~@oEm  
{ Jg;[k  
siteInfoBean = bean; @01.Pd
  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); iHGVR  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); A.vAk''(}+  
if(tmpFile.exists ()) |${4sUR  
{ 7.hBc;%2u  
bFirst = false; Uv(R^50>  
read_nPos(); %xlpOR4  
} *'-4%7C`1  
else &SE}5
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{ EwzR4,r\M  
nStartPos = new long[bean.getNSplitter()]; KVa{;zBwl  
nEndPos = new long[bean.getNSplitter()]; E2'Wzrovlo  
} -U/)y:k!%  
1 %P-X!  
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} x vs=T  
* @4@eQF  
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public void run() o99ExQ.  
{ <{kPa_`'  
//获得文件长度 _u[tv,  
//分割文件 8OZj24*'DS  
//实例FileSplitterFetch <-v zS;  
//启动FileSplitterFetch线程 m[}k]PB>  
//等待子线程返回 Ic2?1<IZA  
try{ 
jw:z2:0~  
if(bFirst) S[zvR9AW&  
{ ]eKuR"ob0  
nFileLength = getFileSize(); CM_hN>%w[  
if(nFileLength == -1) 4=^_VDlpd  
{ ]o<]A[<  
System.err.println("File Length is not known!"); Kz"3ba}KH  
} idYB.]Y(  
else if(nFileLength == -2) eTa_RO,x  
{ ,ErfTg&^  
System.err.println("File is not access!"); y|6n:<o  
} .G[/4h :.  
else G?$@6  
{ ='h2z"}\Bn  
for(int i=0;i<nStartPos.length;i++) NfvPE]S  
{ :*}Q/]N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =x8[%+  
} \ASt&'E  
for(int i=0;i<nEndPos.length-1;i++) c*)T4n[e  
{ fkZHy|m  
nEndPos = nStartPos[i+1]; F@u7Oel@m  
} ]Lub.r  
nEndPos[nEndPos.length-1] = nFileLength; }3{eVct#|  
} k_7m[o  
} ;7P'>j1?U  
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'dKfXYY1`N  
//启动子线程 wb$uq/|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .g8*K "  
for(int i=0;i<nStartPos.length;i++) `9^tuR,  
{ |{N{VK  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +K1M&(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KR>)Ek  
nStartPos,nEndPos,i); Iq+N0G<j  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Pf[E..HF*d  
fileSplitterFetch.start(); OIP]9lM$nC  
} A<+Dx  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5s[nE\oaG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1p}Wj*mc  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l{[@Ahb}?  
nEndPos = " + nFileLength); '0HOL)cIz  
// fileSplitterFetch[nPos.length-1].start(); O-(V`BZe  
.?45:Ey~g  
QOB^U-cW  
//等待子线程结束 NIs7v  
//int count = 0; Mh)?A/e  
//是否结束while循环 D~C'1C&W  
boolean breakWhile = false; Y*NzY*V\  
cyCh^- <l@  
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while(!bStop) <8:h%%$?  
{ \l59/ZFan  
write_nPos(); :*Wq%Y=  
Utility.sleep(500); : "85w#r  
breakWhile = true; s)E  \  
}X)vktE+|  
O%EA,5U.  
for(int i=0;i<nStartPos.length;i++) ["3dr@T9Z  
{ &&
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if(!fileSplitterFetch.bDownOver) A8m06  
{ 1$&@wG  
breakWhile = false; L_Ok?9$  
break; 4'O,xC  
} ?9~^QRLT  
} ;XN|dq  
if(breakWhile) aZmN(AJ8v  
break; ,Wlt[T(.;  
/J
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5NhFjPETr  
//count++; j*
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//if(count>4) a}UmD HS-  
// siteStop(); Jy(G A  
} GL n M1  
;u<Ah?w=Z  
<X)\P}"L4  
System.err.println("文件下载结束！"); /*#o1W?wQZ  
} ;5tOQ&p%v  
catch(Exception e){e.printStackTrace ();} Jq/itsg  
} ]E/0iM5  
zZ%[SW&vC  
tj13!Cc}e`  
//获得文件长度 yT7$6x  
public long getFileSize() 'I$FOH  
{ (ghI$oH  
int nFileLength = -1; GLf!i1Z  
try{ -EiTP:A  
URL url = new URL(siteInfoBean.getSSiteURL()); J p?XV<3Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IJ Jp5[w  
httpConnection.setRequestProperty("User-Agent","NetFox"); E{\CE1*  
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r!Eh}0bL  
int responseCode=httpConnection.getResponseCode(); OijuOLt  
if(responseCode>=400) NxHUOPAJc  
{ X)3(.L  
processErrorCode(responseCode); jrQ0-D%M d  
return -2; //-2 represent access is error aC,adNub  
} Z}S[
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#^T`vTD-  
3F;C{P!  
String sHeader; G&*P*f1S  
7"(Zpu  
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for(int i=1;;i++) D{+@ ,C7B  
{ u$d[&|`>_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q a (Sb  
//Utility.log(in.readLine()); +?*;#=q  
sHeader=httpConnection.getHeaderFieldKey(i); KL_/f   
if(sHeader!=null) ,`Hwe
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{ R #wZW&N  
if(sHeader.equals("Content-Length")) ,j_js8r  
{ E;a,].  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));  t;o\"H  
break; F'K >@y  
} cr!8Tp;2A  
} aGbG@c8PRi  
else 5SY%B#;5G  
break; bWo  
} kPX+n+$  
} B/4M;G~  
catch(IOException e){e.printStackTrace ();} 0b{jox\!B  
catch(Exception e){e.printStackTrace ();} q=X<QhK  
Al^tM0T^  
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Utility.log(nFileLength); JK!(\Ae.  
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return nFileLength; 9)VAEyv  
} 3RtVFDIZA"  
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k?fz @H8D(  
//保存下载信息（文件指针位置） j#//U2VdN  
private void write_nPos() A]bQUWt2  
{ %tVU Rj  
try{ (,I:m[0  
output = new DataOutputStream(new FileOutputStream(tmpFile));
21v--wZ  
output.writeInt(nStartPos.length); sx#O3*'>1  
for(int i=0;i<nStartPos.length;i++) 76w[X=Fv  
{ 5sJ>+Rg  
// output.writeLong(nPos); )h]+cGM  
output.writeLong(fileSplitterFetch.nStartPos); 7z;2J;u`n  
output.writeLong(fileSplitterFetch.nEndPos); k{+cFG\C&  
} q9
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output.close(); 4FaO+Eo,8  
} Z|_V ;*  
catch(IOException e){e.printStackTrace ();} 4V:W 8k 9D  
catch(Exception e){e.printStackTrace ();} x:)H Ii q/  
} 6u"wgX]H  
6(QfD](2}  
p(RF   
//读取保存的下载信息（文件指针位置） wH|%3@eJ  
private void read_nPos() cP?GRMX@}  
{ X;!*D  
try{ Dl/ C?Fll  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }uIQ@f`  
int nCount = input.readInt(); ?2"g*Bak  
nStartPos = new long[nCount]; jemb/:E  
nEndPos = new long[nCount]; 5ngs1ZF@  
for(int i=0;i<nStartPos.length;i++) Iy_5k8]  
{ AZ!/{1Az  
nStartPos = input.readLong(); AW
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nEndPos = input.readLong(); Pn9".  
} lj]M 1zEz&  
input.close(); j55_wx@cA  
} c^w^'<  
catch(IOException e){e.printStackTrace ();} 4pL'c@'  
catch(Exception e){e.printStackTrace ();} Cj>HMB}  
} &n1Vv_Lb  
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private void processErrorCode(int nErrorCode) ]+e zg(C}  
{ 9Z-2MF  
System.err.println("Error Code : " + nErrorCode); 5J`w8[;  
} %X_A#9  
' wl})  
nT|WJ%  
//停止文件下载 )cH\i91  
public void siteStop() O]XRalkEM  
{ bVcJ/+Yx|  
bStop = true; h?TIxo:6/  
for(int i=0;i<nStartPos.length;i++) 807+|Ol[  
fileSplitterFetch.splitterStop(); I q|'#hs  
,9y6:W%5  
Kii@Z5R_?  
} +j: &_  
} X8tPn_`x  
//负责部分文件的抓取 h>V6}(~;.  
**FileSplitterFetch.java 4Y?fbb<  
*/ 76T7<.S  
package NetFox; ~;oXLCL0})  
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_!2lnJ4+5  
import java.io.*; |4DN2P  
import java.net.*; N@PuC>  
;\th.!'rn  
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public class FileSplitterFetch extends Thread { 46vC/  
">7xSWR*4  
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String sURL; //File URL ddL3wQ  
long nStartPos; //File Snippet Start Position ;X+0,K3c  
long nEndPos; //File Snippet End Position ubB1a_7  
int nThreadID; //Thread's ID rZ,q
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boolean bDownOver = false; //Downing is over MZ%J ]
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boolean bStop = false; //Stop identical i@:^b_  
FileAccessI fileAccessI = null; //File Access interface -$!r+4|q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e_!h>=$%8  
{ &</)k|.A6\  
this.sURL = sURL; lfBCzxifC  
this.nStartPos = nStart; `0ZH=*P  
this.nEndPos = nEnd; 9L7z<ntn  
nThreadID = id; (w-"1(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0VvY(j:hp  
} "
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public void run() zji9\  
{ eLT3b6'"?  
while(nStartPos < nEndPos && !bStop) ~V(>L=\V;  
{ 8/2Wq~&  
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try{ .;31G0<w2  
URL url = new URL(sURL); u"5/QB{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J4]"@0?6  
httpConnection.setRequestProperty("User-Agent","NetFox"); Hd4 ~v0eS  
String sProperty = "bytes="+nStartPos+"-"; iM!V4Wih6  
httpConnection.setRequestProperty("RANGE",sProperty); 7r,GdP.  
Utility.log(sProperty); V@+sNM  
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InputStream input = httpConnection.getInputStream(); 1<h@^s;  
//logResponseHead(httpConnection); /7B3z}rd  
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byte[] b = new byte[1024]; _&(Wz0  
int nRead; 8r}tf3xMCM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %^W(sB$b  
{ \aSc2Ml]3n  
nStartPos += fileAccessI.write(b,0,nRead); 6!)hl"  
//if(nThreadID == 1) bZSt<cH3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =?L16mu1&  
} )%/ Ni^  
"o%okN  
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Utility.log("Thread " + nThreadID + " is over!"); 1V5N)ty  
bDownOver = true; [*K9V/  
//nPos = fileAccessI.write (b,0,nRead); y=8KNse
W|  
} gs}&a3d7k  
catch(Exception e){e.printStackTrace ();} B$c'^ )  
} /slCK4vFc  
} H1~9f{
 
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,P`:`XQ>_B  
//打印回应的头信息 [)}`w;#  
public void logResponseHead(HttpURLConnection con) UptKN|S&V  
{ x15&U\U  
for(int i=1;;i++) %eF=;q  
{ k FRVW+  
String header=con.getHeaderFieldKey(i); ci%$So2#  
if(header!=null) WjVm{7?{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [)X(Qtk  
Utility.log(header+" : "+con.getHeaderField(header)); R(> oyxA[F  
else 5 3+C;]J  
break; ixy:S1pI  
} o7tlkSZ  
} ,*Wh{
)  
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public void splitterStop() MG&vduu  
{ Cjt].XR@  
bStop = true; R8.@5g_  
} c~M'O26bW  
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1"A"AMZf  
} (eT9N_W  
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9u^za!pE  
/* U2Siw  
**FileAccess.java ZdhA:}~^E  
*//文件访问(定位，写) QeQwmI  
package NetFox; uf)!SxT  
import java.io.*; Ayw {I#"  
Ng&K5Z/  
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public class FileAccessI implements Serializable{ \Vj7%ph  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?MRT  
RandomAccessFile oSavedFile;
rJ4A9d3:  
long nPos; mst;q@  
'uqY%&U  
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public FileAccessI() throws IOException 8N<2RT8W  
{ .4z_ohe  
this("",0); 0 4ceDe  
} !9S!zRy@  
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public FileAccessI(String sName,long nPos) throws IOException lR ZuXo9<  
{ /jc; 2  
oSavedFile = new RandomAccessFile(sName,"rw"); ){J,Z*&  
this.nPos = nPos; =
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oSavedFile.seek(nPos); rgv$MnG  
} Wsw/ D  
{f6~Vwf  
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public synchronized int write(byte[] b,int nStart,int nLen) 1A7(s0J8 :  
{ !&G& ~*.x  
int n = -1; %Bnn\{Az  
try{ 0#sf,
ja>  
oSavedFile.write(b,nStart,nLen); bhjJH,%_>  
n = nLen; r*Z p-}  
} pr\OjpvD  
catch(IOException e) 78'3&,+si  
{  N,ihQB5  
e.printStackTrace (); Xj6?,J  
} s=&x%0f%  
!M7727  
Coe%R(x5  
return n; x*_'uPoS  
} &K"qnng/y  
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>{h/4T@  
} /a-OBU  
7@!ne&8Z?  
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/* %vWh1-  
**SiteInfoBean.java #"J
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*/ !y;xt?  
package NetFox; vcp[$-$QGJ  
G
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public class SiteInfoBean { )K0rPnYV  
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?
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private String sSiteURL; //Site's URL $2v{4WP7G  
private String sFilePath; //Saved File's Path Y7@$#/1  
private String sFileName; //Saved File's Name ]%6XE)  
private int nSplitter; //Count of Splited Downloading File <`=(Ui$fD  
pTcN8E&Unz  
^' b[#DG>F  
public SiteInfoBean() Z2{G{]EV(  
{//nSplitter的缺省值为5 3B ;aoejHm  
//default value of nSplitter is 5 sTzt  
this("","","",5); ";/,FUJJ  
} 8|S}!P"  
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$-BM`Zt0;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
}FAO.  
{ D]5cijO6  
sSiteURL= sURL; R|t.JoP9  
sFilePath = sPath; #7,;/rtO7  
sFileName = sName; 8CGjI?j  
this.nSplitter = nSpiltter; |D[4G6&  
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} 5tu 4uYp;  
Ov~>* [  
)tR@\G>%  
public String getSSiteURL() V%'+ ob6  
{ !Im{-t  
return sSiteURL; Ub*O*nre  
} CW;=q[+
w  
hT$/B|  
CoQ<Ky}*  
public void setSSiteURL(String value) r|0wIpi6Q  
{ :"~n` Q2[  
sSiteURL = value; C1SCV^#  
} $n9Bp'<  
{-e|x&-  
3q$"`w  
public String getSFilePath() ]=T-Cv=t  
{ A{KF<Omu  
return sFilePath; i|OG#PsY-  
} ~_hn{Ous  
(GDW9:  
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public void setSFilePath(String value) CUZ ;<Pn  
{ \6c8Lqa  
sFilePath = value; }E](NvCq  
} vvcA-k?  
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public String getSFileName() ;UDd4@3`S"  
{ KMogwulG  
return sFileName; ?CUGJT
 
} Tn 3<cO7v  
u|D|pRM-LT  
;*409P  
public void setSFileName(String value) 8k -l`O~  
{ ^Jdji:  
sFileName = value; vSG$2g=  
} )l"py9
STF  
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6,UW5389  
public int getNSplitter() UU"'  
{ d{G*1l(X  
return nSplitter; We*&\e+"T  
} *B1%-  
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"jMSF@lr  
public void setNSplitter(int nCount) k_hs g6Ur.  
{ Q"=$.M~  
nSplitter = nCount; a!Ht81gj  
} 7,&
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} { x/~gp
 
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eg Zb)pP  
/* 4vb
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**Utility.java G [$u`mxV^  
*/ Bi$nYV)-l  
package NetFox; G[M{TS3&Ds  
2 rx``,7Q  
1/%g VB8  
public class Utility { `c%{M4bF\  
x|`o7.  
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public Utility() k9vzxZ%s:  
{ m6^n8%  
<maYS2  
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} l.`f^K=8  
A~MIFr/8  
//线程睡眠 ym.:I@b?6  
public static void sleep(int nSecond) p`2w\P3;)  
{ Y$&+2w,)H,  
try{ s(MLBV5)w  
Thread.sleep(nSecond); 3}9c0%}F  
} o/5loV3h  
catch(Exception e) 1&Ruz[F5  
{ 7\nR'MOZ  
e.printStackTrace (); Tq*K =^  
} 5svM3  #  
} IFfB3{J  
CFyu9Al  
//日志 akB+4?+s)  
public static void log(String sMsg) WG=~GDS>  
{ Vp j[)W%L  
System.err.println(sMsg); <Gkmk?x`A  
} z)&ZoSXWc  
^7>k:|7-t  
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public static void log(int sMsg) "D1u2>(  
{ i]M:ntB"  
System.err.println(sMsg); * j]"I=D  
} 
2GC{+*  
} 9qXKHro
 
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]p5]n*0X  
/* uA~T.b\  
**TestMethod.java dAkJ5\=*  
*/ 052ezh_  
package NetFox; 7IUu] Fi  
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IP=."w  
public class TestMethod { FhVoN}  
lbUUf}   
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public TestMethod() # )]L3H<  
{ ///xx/weblogic60b2_win.exe 7;x}W-`iF  
try{ w_h}c$;GK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); CPt62j8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &x>8 %Q s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &2\^S+4  
fileFetch.start(); LL"c 9jb4z  
} j8#xNA  
catch(Exception e){e.printStackTrace ();} ]
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} `_Fxb@"R  
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m(o^9R_=^9  
public static void main(String[] args) "nQ&~KQ  
{ (HD8Mm  
new TestMethod(); uXkc07 r'  
} F\IJim-Rh  
} hF;TX.Y6  
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