http断点续传简单实现（java)

/* x$6FvgP(  
**SiteFileFetch.java dt(Lp_&v  
*/ N~9zQ  
package NetFox; %QX"oRMn0  
import java.io.*; ?^{Ey[)'(  
import java.net.*; | @p  
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public class SiteFileFetch extends Thread { RzqU`<//  
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SiteInfoBean siteInfoBean = null; //文件信息Bean yeN(_t2.  
long[] nStartPos; //开始位置 #,rP1#?  
long[] nEndPos; //结束位置 K=!?gd!Vw  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !&Us^Q^  
long nFileLength; //文件长度 \D}$foHg  
boolean bFirst = true; //是否第一次取文件 4 zipgw  
boolean bStop = false; //停止标志 n2&M?MGX  
File tmpFile; //文件下载的临时信息 WmZ,c_  
DataOutputStream output; //输出到文件的输出流 *5R91@xt  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） y?8V'.f|  
public SiteFileFetch(SiteInfoBean bean) throws IOException Fzn#>`qG  
{ _)^`+{N<  
siteInfoBean = bean; IYB;X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }r:8w*47  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~D!Y] SK  
if(tmpFile.exists ()) 8iN@n8O  
{ ,pVq/1  
bFirst = false; +fG~m:E  
read_nPos(); ufS0UD8%H  
} h
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else n16TQe"8  
{ *ZF:LOnU  
nStartPos = new long[bean.getNSplitter()]; eHH9#Vrhc$  
nEndPos = new long[bean.getNSplitter()]; gOm%?sg  
} \`WAG>'l5  
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} u&$1XZ!es  
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public void run() `-<m#HF:)d  
{ Bt"*a=t;  
//获得文件长度 ]`eJSk.  
//分割文件 N"/be  
//实例FileSplitterFetch =N{-lyr)  
//启动FileSplitterFetch线程 H9rZWc"*  
//等待子线程返回 qN6
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try{ mW @Z1Plxs  
if(bFirst) rcG-Vf@  
{ [
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nFileLength = getFileSize(); 9XW[NY#)#  
if(nFileLength == -1) fFd"21>  
{ a|@1RH>7H  
System.err.println("File Length is not known!"); 4mF=A$Q_/  
} 8!Q0:4Vb  
else if(nFileLength == -2) Dlo4Wy  
{ JL&ni]m  
System.err.println("File is not access!"); 'pl){aL`@u  
} 4t0-L]v4.*  
else j0IuuJ+  
{ !6{b)P  
for(int i=0;i<nStartPos.length;i++) >s"kL^  
{ }o9(Q8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?1lx8+  
} N;XJMk_ H  
for(int i=0;i<nEndPos.length-1;i++) |NaEXzo|qY  
{ +/2:  
nEndPos = nStartPos[i+1]; &6@e9ff0  
} vKNxL^x  
nEndPos[nEndPos.length-1] = nFileLength; ?iNihE  
} w0$l3^}z  
} X>VxE/  
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[:-o;K\.-a  
//启动子线程 *(]@T@yN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; wvg>SfV,e  
for(int i=0;i<nStartPos.length;i++) S:xG:[N@  
{ =/F\_/Xw  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S[oRq   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xm}`6B^f  
nStartPos,nEndPos,i); QzA/HP a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8rgNG7d  
fileSplitterFetch.start(); %dA7`7j  
} b. oA}XP  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q OP8{~O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Se&%Dr3Nv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", AC/82$  
nEndPos = " + nFileLength); 2[$` ]{U  
// fileSplitterFetch[nPos.length-1].start(); <t4l5nr#  
Wy,Tf*[  
<=7^D  
//等待子线程结束 vxx7aPjC  
//int count = 0; 'C|yUsBC  
//是否结束while循环 h5R5FzY0&  
boolean breakWhile = false; H1g"09?h6o  
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while(!bStop) IDr$Vu4LCW  
{ E[E[Za^Y  
write_nPos(); RVb}R<yU+  
Utility.sleep(500); Z )dz  
breakWhile = true; ZVmgQ7m  
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for(int i=0;i<nStartPos.length;i++) B%d2tsDw  
{ 7U{g'<  
if(!fileSplitterFetch.bDownOver) [!E~pW%|n  
{ D^W?~7e^r  
breakWhile = false; I@9k+JB
  
break; OM 5h>\9  
} haMt2S2_B:  
} za@`,Yq  
if(breakWhile) ^YG.eT6iG  
break; cYMlcwS  
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//count++; y1:#0  
//if(count>4) <sq@[\l}a  
// siteStop(); 7lz"^  
} jNA^ (|:  
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System.err.println("文件下载结束！"); <xeo9'k6&  
} y*5bF0  
catch(Exception e){e.printStackTrace ();} Gd5J<K  
} Q.G6y,KR  
tkGJ!aUt  
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//获得文件长度 y}bE'Od  
public long getFileSize() *T'>-nm]  
{ +k4SN  
int nFileLength = -1; h&6v&%S/L  
try{ *m[ow s  
URL url = new URL(siteInfoBean.getSSiteURL()); <C9_5Ce~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8L7ZWw d  
httpConnection.setRequestProperty("User-Agent","NetFox"); i@M^9|Gh  
D>Qc/+  
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int responseCode=httpConnection.getResponseCode(); I5J9,j  
if(responseCode>=400) Gp/yr  
{ q={\|j$X  
processErrorCode(responseCode); ]}&f
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return -2; //-2 represent access is error $lMEZt8A  
} r%/*,lLO  
/)` kYD6  
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String sHeader; )} H46  
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for(int i=1;;i++) E5<}7Pt  
{ VfiMR%i}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NN9`jP2  
//Utility.log(in.readLine()); H `V3oS~}  
sHeader=httpConnection.getHeaderFieldKey(i); (fjAsbT  
if(sHeader!=null) ]7, mo  
{ /8SQmh$+e  
if(sHeader.equals("Content-Length")) 6*<=(SQI  
{ nVC:5ie  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1wa zJj=v  
break; a!>yX ex  
} I!ykm\<  
} bVc;XZwI  
else |&t 2jD(  
break; ui:  
} \&p MF  
} '}{J;moB  
catch(IOException e){e.printStackTrace ();} N'nqVYTU  
catch(Exception e){e.printStackTrace ();} -/.Xf<y58  
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Utility.log(nFileLength); |6pNe T[  
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return nFileLength; l ^*GqP5  
} /IS j0"/$  
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//保存下载信息（文件指针位置） jy] hP?QG  
private void write_nPos() Dm j^aFB0|  
{ F-)lRGw  
try{ <}3c%Q1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %7PprN0>  
output.writeInt(nStartPos.length); 6.Nu[-?  
for(int i=0;i<nStartPos.length;i++) uLsGb=m%b  
{ `A)9   
// output.writeLong(nPos); IwIk;pB O  
output.writeLong(fileSplitterFetch.nStartPos); .Y%)&  
output.writeLong(fileSplitterFetch.nEndPos); nL+*-R!R  
} Hb3+$vJ^  
output.close(); bN$!G9I!,  
} BHE((3  
catch(IOException e){e.printStackTrace ();} a<%WFix  
catch(Exception e){e.printStackTrace ();} 28;D>6c  
} pHFh7-vj  
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)K8k3]y&  
//读取保存的下载信息（文件指针位置） 5O Ob(  
private void read_nPos() 4-4lh TE(  
{ \]U@=w  
try{ \*H/YByTb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); dF{3~0+,  
int nCount = input.readInt(); j[XA"DZR<  
nStartPos = new long[nCount]; 8z^?PZ/  
nEndPos = new long[nCount]; _M+'30  
for(int i=0;i<nStartPos.length;i++) x=yU }lsV  
{ x-0IxWD%  
nStartPos = input.readLong(); <_02)6j  
nEndPos = input.readLong(); J<Wz3}w6  
} aXyu%<@k  
input.close(); EOrWax@k$}  
} ~y}M GUEC  
catch(IOException e){e.printStackTrace ();} z[DUktZl  
catch(Exception e){e.printStackTrace ();} URDb  
} 5#.uA_Fov  
2,O-/A;tW*  
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private void processErrorCode(int nErrorCode) dhN[\Z%  
{ =z]&E 78Y  
System.err.println("Error Code : " + nErrorCode); K,[g<7X5  
} 2*
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//停止文件下载 TRrO-  
public void siteStop() 0K'lr;  
{ <
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bStop = true;
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for(int i=0;i<nStartPos.length;i++) rm>;B *;  
fileSplitterFetch.splitterStop(); v#.FK:u}  
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} D>,]EE-  
} !Y-MUZ$f  
//负责部分文件的抓取 kwdmw_  
**FileSplitterFetch.java 5+GW%U/  
*/ h)q:nlKUW  
package NetFox; PG9won5_  
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import java.io.*; g/so3F%v .  
import java.net.*; D5)qmu  
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public class FileSplitterFetch extends Thread { t'4hWNR'  
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String sURL; //File URL k+44ud.j  
long nStartPos; //File Snippet Start Position ={b/s31H:  
long nEndPos; //File Snippet End Position y-}lz#N  
int nThreadID; //Thread's ID 2GcQh]ohc  
boolean bDownOver = false; //Downing is over ]Ole#Lz}Q  
boolean bStop = false; //Stop identical /`0*!sN*5  
FileAccessI fileAccessI = null; //File Access interface AqvRzi(Y  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &Z5$ 5,[  
{ 0G9@A8LU  
this.sURL = sURL; Giz9jzF\  
this.nStartPos = nStart; *#Hi W)  
this.nEndPos = nEnd; ]c+qD,wqt>  
nThreadID = id; TQ" [2cY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 AynWs5|z=  
} |!dyk<}oIu  
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public void run() 2Ua_7  
{ \P!v9LX(  
while(nStartPos < nEndPos && !bStop) a2UER1Yp"  
{ 7i~::Z <  
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try{ P$2J`b[H$  
URL url = new URL(sURL); 2Y&z}4'j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,]~iIoTi  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6-gxba  
String sProperty = "bytes="+nStartPos+"-"; {O#=%o[  
httpConnection.setRequestProperty("RANGE",sProperty); K8{j oh  
Utility.log(sProperty); .%3bXK+F  
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InputStream input = httpConnection.getInputStream(); J @"wJEF  
//logResponseHead(httpConnection); d7^:z%Eb|  
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byte[] b = new byte[1024]; $2Ox;+  
int nRead; )qD%5} t  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) y ']>J+b0  
{ H0 km*5Sn  
nStartPos += fileAccessI.write(b,0,nRead); qDhz|a#  
//if(nThreadID == 1) 1;SW%\M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *f.eyg#  
} M\,0<{  
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Utility.log("Thread " + nThreadID + " is over!"); DkA cT[  
bDownOver = true;
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//nPos = fileAccessI.write (b,0,nRead); "f~S3?^!2  
} TuBg4\V  
catch(Exception e){e.printStackTrace ();} HV&N(;@  
} k x6%5%  
} R7e`Wn  

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 #It{B  
//打印回应的头信息 aT(Pf7 O  
public void logResponseHead(HttpURLConnection con) '%V ;oJ"  
{ zkI\ji  
for(int i=1;;i++) Jm\'
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{ 0^]E-Zf  
String header=con.getHeaderFieldKey(i); `HgT5}  
if(header!=null) 7&:gvhw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); JE9|;A  
Utility.log(header+" : "+con.getHeaderField(header)); el.;T*Wn  
else QZ"Lh  
break; j3P)cz-0/L  
} er,R}v  
} h;^h[q1'  
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Bb]

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public void splitterStop() {]]nQ  
{  qeBfE  
bStop = true; @?3u|m |Z  
} (#eB%  
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} ~ra2Xyl  
+~ :1H.  
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/* BGodrb1  
**FileAccess.java wP6~HiC  
*//文件访问(定位，写) $o
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package NetFox; bh6Mh<+  
import java.io.*; g/mVd;#o  
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public class FileAccessI implements Serializable{ /o.wCy,J<  
E[Tz%x=P  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HpSgGhL'J&  
RandomAccessFile oSavedFile; ]b.@i&M  
long nPos; IpoZ6DB$  
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public FileAccessI() throws IOException &rorBD 5aj  
{ 7X2g"2\Wm  
this("",0); E3_e~yu&  
} 6*S|$lo9B  
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9vmH$  
public FileAccessI(String sName,long nPos) throws IOException uz&CUvos  
{ R6h(mPYA  
oSavedFile = new RandomAccessFile(sName,"rw"); 8PDt 7 \  
this.nPos = nPos; O!hg@[\B+  
oSavedFile.seek(nPos); p` B48TW  
} 'vhgR2/  
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k5$_Q#  
public synchronized int write(byte[] b,int nStart,int nLen) J1 a/U@"  
{ E&#AX:  
int n = -1; vy,ER<  
try{ FaPX[{_E  
oSavedFile.write(b,nStart,nLen); Jq l#z/z  
n = nLen; =~?2i)-mC  
} ?M;2H{KG:  
catch(IOException e) QSW03/_f  
{ gPT-zul  
e.printStackTrace (); 245(ajxHC  
} bkceR>h%  
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return n; yj `b-^$?  
} M9_ y>N[0  
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} ..Zuy|?w  
5:hajXd  
!Q*.Dw()[  
/* 9FP6Z[4  
**SiteInfoBean.java '6Ybf  
*/ 1wW8D>f]K  
package NetFox; x9a*^l  
KX"?3#U#Fm  
t*.O >$[  
public class SiteInfoBean { .YYiUA-i9n  
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private String sSiteURL; //Site's URL (i.MxGDd  
private String sFilePath; //Saved File's Path Cj _Q9/  
private String sFileName; //Saved File's Name ua0`&,a3I  
private int nSplitter; //Count of Splited Downloading File WQ\'z?P  
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public SiteInfoBean() WLP A51R  
{//nSplitter的缺省值为5 Qi&!IG  
//default value of nSplitter is 5 X{| 1E85fl  
this("","","",5); )r~$N0\D  
} %DqF_4U9  
J|W~\(W6i  
?#-"YO7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3=o3VGZP  
{ Y1rU  
sSiteURL= sURL; -n?|,cO  
sFilePath = sPath; qx18A  
sFileName = sName; 8+k\0fmy  
this.nSplitter = nSpiltter; MSUkCWt!  
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[D[s^<RJs  
} h1z[ElEeoP  
nC
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public String getSSiteURL() ]!d #2(  
{ MOP/q4j[  
return sSiteURL; 'VS!<  
} R56:}<Y,  
_k\*4K8L  
-7fsfcGM$  
public void setSSiteURL(String value) /+1+6MqRn*  
{ B[Fx2r`0  
sSiteURL = value; R(74Px,/  
} >)=FS.?]  
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public String getSFilePath() ZF_*h`B  
{ MRxzOs  
return sFilePath; sTP`xaY  
} >2x[ub%$L  
Gw:8-bxS  
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public void setSFilePath(String value) XpJT
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{ (@B gsY  
sFilePath = value; v?,_SVgAi  
} G%Hr c  
%{!*)V\  
KS!mzq-  
public String getSFileName() !X$e;V"HX  
{ |>5NH'agV  
return sFileName; )'?3%$EM  
} iOkRBi  
&#;vR0O  
oTS*k: C'  
public void setSFileName(String value) luAC
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{ -|\V'  
sFileName = value; {f((x1{HZx  
} =H%c/Jty  
v#q7hw=  
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public int getNSplitter() i^eU!^KF  
{ #f0J.)M  
return nSplitter; bX6eNk-L  
} :aI[ lZ  
1Jg&L~Ws"  
y2;uG2IS_g  
public void setNSplitter(int nCount) &m&Z^CA  
{ `wj<d>m  
nSplitter = nCount; KC9_H>  
} %JeT,{  
} ekND>Qjj  
8iaP(*J  
y!&6"l$K]  
/* .aV#W@iyK  
**Utility.java Eyv%"+>  
*/
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package NetFox; Hphvsre<  
0"o%=i;  
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public class Utility { tGDsZ;3Yr  
LG0+A}E=C  
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public Utility() BF{v0Z0/}k  
{ FBJw (.Jr  
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-L%tiz`_  
} 3qwi)nm  
w/BaaF.0  
//线程睡眠 _^]2??V  
public static void sleep(int nSecond) F6J,:  
{ c}v>Mx  
try{ %MGbIMpY  
Thread.sleep(nSecond); >Vc;s!R  
} .Y|5i^i9{  
catch(Exception e) aqJ>l}{  
{
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e.printStackTrace (); 6..G/,T
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} 0aj4.H*%  
} gg $/  
TR}ztf[e  
//日志 mucKmb/  
public static void log(String sMsg) [hC-} 9  
{ =kFZ2/P2t(  
System.err.println(sMsg); }TE4)vXs  
} 7vO3+lT/Y;  
i E p{  
uvC ![j^~  
public static void log(int sMsg) 9jW/"  
{ M9so3L<N0  
System.err.println(sMsg); $fZVh%  
} ;|7]%Z}%  
} 3H"bivK
 
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/* xh|NmZg  
**TestMethod.java _voU^-  
*/ 21ng94mC  
package NetFox; 0 ~K4vSa  
|uL"/cMW7  
6WUP
#c@{  
public class TestMethod { L-SWs8  
 {}x{OP  
~Y;_vU  
public TestMethod() bDK%vx!_  
{ ///xx/weblogic60b2_win.exe fP 4  
try{ J;@g#h?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,F^Rz.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'KL!)}B$h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ROH 2KSt  
fileFetch.start(); vhsHyb  
} ]1YyP  
catch(Exception e){e.printStackTrace ();} fbv%&z  
\ k&(D*u  
o+-G@16  
} >Vp#  
~t0\Q; @($  
*F[;D7sZ~  
public static void main(String[] args) 3pQ^vbQ"  
{ y?Vsp<  
new TestMethod(); 1=NP=ZB  
} JSKAlw  
} +E5EOo{ `|  
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