http断点续传简单实现（java)

/* 2 ":W^P  
**SiteFileFetch.java Jk=_8Xvr`  
*/ ^&Vj m  
package NetFox; p}e1!q;N  
import java.io.*; 1DRih>+#  
import java.net.*; mDdL7I  
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public class SiteFileFetch extends Thread { )R^&u`k  
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SiteInfoBean siteInfoBean = null; //文件信息Bean +l27y0>t  
long[] nStartPos; //开始位置 i9+qU  
long[] nEndPos; //结束位置 *Roqie  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'ju'O#A9  
long nFileLength; //文件长度 5q,ZH6\ {  
boolean bFirst = true; //是否第一次取文件 xOt {Vsv  
boolean bStop = false; //停止标志 wTe 9OFv  
File tmpFile; //文件下载的临时信息 5"9'=LV~  
DataOutputStream output; //输出到文件的输出流 BVzMgn;  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） j"r7M|Z+V  
public SiteFileFetch(SiteInfoBean bean) throws IOException !nDiAjj  
{ !O 0{ .k  
siteInfoBean = bean; ],-(YPiAD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `lcQ Yd<,4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,(3oAj\  
if(tmpFile.exists ()) 2DNB?,uP,'  
{ A}4 ",  
bFirst = false; p#0L@!,  
read_nPos(); ('z:XW96  
} `$t|O&z  
else po@Agyg5  
{ 3|Y2BAd  
nStartPos = new long[bean.getNSplitter()]; 0dW*].Gi:  
nEndPos = new long[bean.getNSplitter()]; -, uT8'  
} 'm^]X3y*  
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} #h}a   
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public void run() hem>@Bp'V  
{ n
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//获得文件长度 7{lWg x  
//分割文件 : "^/?Sd  
//实例FileSplitterFetch kx,3[qe'S  
//启动FileSplitterFetch线程 %v4*$E!f  
//等待子线程返回 5t,X;  
try{ i`}!<
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if(bFirst) WBWIHv{j  
{ k&9[}a*  
nFileLength = getFileSize(); Bn{i+8I  
if(nFileLength == -1) wx8Qz,Z  
{ Q9Vj8JO"{  
System.err.println("File Length is not known!"); _<%YLv  
} w0X})&,{`m  
else if(nFileLength == -2) 12@Ge]  
{ ~gdnD4[G  
System.err.println("File is not access!"); ?sv[vR(  
} a+^,EY  
else SUDvKP  
{ WP{U9YF2  
for(int i=0;i<nStartPos.length;i++) &NX7  
{ Qp9QSyMs}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8ZCR9%  
} 'Q"Mu  
for(int i=0;i<nEndPos.length-1;i++) eD|"?@cE  
{ !u;gGgQF  
nEndPos = nStartPos[i+1]; 3 MCV?"0  
} ${e5Ka  
nEndPos[nEndPos.length-1] = nFileLength; wb>"'%  
} qr(t_qR&  
} yqC158 P  
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//启动子线程 R|92T*h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) .%+anVXS  
{ Y;"jsK{$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PJT$9f~3;.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +4+czfz  
nStartPos,nEndPos,i); i9|}-5ED  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L d{`k  
fileSplitterFetch.start(); +2w<V0V_  
} m.FN ttkM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~ike&k{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); WRrg5&._q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hC4 M}(XM  
nEndPos = " + nFileLength); nRyx2\Py+  
// fileSplitterFetch[nPos.length-1].start(); vVZ+u4y  
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//等待子线程结束 p=V1M-  
//int count = 0; {55f{5y3 c  
//是否结束while循环 YU XxQ|  
boolean breakWhile = false; D!8v$(#hR  
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while(!bStop) oI
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{ {Iz"]Wh<f  
write_nPos(); +,Or^pO=  
Utility.sleep(500); 3 }3C*w+  
breakWhile = true; Res4;C  
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for(int i=0;i<nStartPos.length;i++) KAi_+/]K_  
{ /l+"aKW 2  
if(!fileSplitterFetch.bDownOver) <\$?.tTZ{  
{ $3gM P+  
breakWhile = false; 7{]L{j-  
break; ]E)D})r`#  
} *\B(-  
} &-!$qUli  
if(breakWhile) F&lH5  
break; A%X=yqY  
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//count++; C^c<s  
//if(count>4) 7VskZbj\  
// siteStop(); Hy -)yR  
} mwMu1
#  
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System.err.println("文件下载结束！"); CpK:u! Dn  
} #s' `bF^  
catch(Exception e){e.printStackTrace ();} :S}ZF$ $j%  
} v$+A!eo  
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//获得文件长度 Aar]eY\  
public long getFileSize() 4.Fh4Y:$'  
{ `gF`Sgz  
int nFileLength = -1; bSn={O"M  
try{ g-,lY|a  
URL url = new URL(siteInfoBean.getSSiteURL()); {U@"]{3Qx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;JgSA&'e  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y]Z&  
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int responseCode=httpConnection.getResponseCode(); CIsX$W  
if(responseCode>=400) AZ4
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{ sva-Sd8  
processErrorCode(responseCode); &y7=tEV  
return -2; //-2 represent access is error \){_\{&  
} K>5bb  
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String sHeader; .:
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for(int i=1;;i++) B5h)F> &G  
{ 7]Hf3]e>/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LNrM`3%2-  
//Utility.log(in.readLine()); |`kkmq  
sHeader=httpConnection.getHeaderFieldKey(i); pAqPHD=  
if(sHeader!=null) O*lIZ,!n  
{ <AiE~l| D  
if(sHeader.equals("Content-Length")) b6H7>x
 
{ Ao*:$:k  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XR p60i6f  
break; lqgR4
!  
} 2^75|Q  
} $P)-o?eer  
else pHye8v4fvi  
break; Cs,Cb2[  
}  _VM}]A  
} ;49sou  
catch(IOException e){e.printStackTrace ();} h,-i\8gq  
catch(Exception e){e.printStackTrace ();} #Ye0*`  
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Utility.log(nFileLength); ;
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return nFileLength; K6)IBV;
 
} I>w|80%%  
[} d39  
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//保存下载信息（文件指针位置） ;PqC*iz  
private void write_nPos() ?5;wPDsK  
{ ^vv1cft  
try{ ME
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output = new DataOutputStream(new FileOutputStream(tmpFile)); .QA1'_9  
output.writeInt(nStartPos.length); Tc>g+eS  
for(int i=0;i<nStartPos.length;i++) 0,):;OI  
{ jq_4x[  
// output.writeLong(nPos); sFvYCRw /  
output.writeLong(fileSplitterFetch.nStartPos); n=0^8QQ  
output.writeLong(fileSplitterFetch.nEndPos); ,J<+Wxz  
} w@YPG{"j  
output.close(); 7|bBC+;(  
} YguW2R=6]  
catch(IOException e){e.printStackTrace ();} FP
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catch(Exception e){e.printStackTrace ();} cRCji^,KJ  
} "(~fl<;  
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//读取保存的下载信息（文件指针位置） m]'+Eye ]r  
private void read_nPos() ep`8LQf  
{ @Jlsx0i}}  
try{ _5b~3K/V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $]W*;MTI}  
int nCount = input.readInt(); &uV|Ie8@q  
nStartPos = new long[nCount]; J-G)mvkv  
nEndPos = new long[nCount]; cg_tJ^vrY  
for(int i=0;i<nStartPos.length;i++) Qw_> l}k/  
{ ;NAKU  
nStartPos = input.readLong(); ;<6S\  
nEndPos = input.readLong(); P]2 /}\f  
} Q84XmXm|  
input.close(); t-iQaobF  
} _`laP5
~  
catch(IOException e){e.printStackTrace ();} .vIRz-S  
catch(Exception e){e.printStackTrace ();} &$#NV@  
} =i2]qj\  
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private void processErrorCode(int nErrorCode) d7x6r3J$  
{ -- IewW  
System.err.println("Error Code : " + nErrorCode); lQt,(@7]  
}
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//停止文件下载 1-<?EOYaE  
public void siteStop() !wKN
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{ ?i!d00X  
bStop = true; >>;He7  
for(int i=0;i<nStartPos.length;i++) Y[
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fileSplitterFetch.splitterStop();  (tT%rj!  
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} Q'j00/K  
} &`-e; Xt  
//负责部分文件的抓取 yV6U<AP$3  
**FileSplitterFetch.java })q8{Qj!  
*/ /nt%VLms%  
package NetFox; !HW?/-\,O  
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import java.io.*; [s%uE+``S  
import java.net.*; g(S4i%\  
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public class FileSplitterFetch extends Thread { >{rD3X"d  
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z_y@4B6>}  
String sURL; //File URL &##JZ  
long nStartPos; //File Snippet Start Position Z^KWYe'w  
long nEndPos; //File Snippet End Position ,W_".aguX  
int nThreadID; //Thread's ID nA=E|$1  
boolean bDownOver = false; //Downing is over M{Vi4ehOq  
boolean bStop = false; //Stop identical 3XUsw1,[  
FileAccessI fileAccessI = null; //File Access interface 9IacZ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7L]Y.7>  
{ ^5FwYXAxi  
this.sURL = sURL; wqX!7rD/g)  
this.nStartPos = nStart; Ro2!$[P
 
this.nEndPos = nEnd; =trLL+vGw'  
nThreadID = id; fCv.$5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _gCi@uXS3  
} Rp}Sm,w(  
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public void run() COH>B1W@  
{ |4` ;G(ta  
while(nStartPos < nEndPos && !bStop) =feVT2*  
{ 'm/`= QX  
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try{ mP_c-qD |  
URL url = new URL(sURL); iTCY $)J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P Qi=  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^c){N-G  
String sProperty = "bytes="+nStartPos+"-"; 8`WaUB%  
httpConnection.setRequestProperty("RANGE",sProperty); ^Uik{x  
Utility.log(sProperty); ^X:g C9  
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InputStream input = httpConnection.getInputStream(); y"w`yl{_  
//logResponseHead(httpConnection);  '^,|8A2  
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byte[] b = new byte[1024]; }SS~uQ;8  
int nRead; 4zqO!nk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Z.U8d(  
{ <bh!wf6;  
nStartPos += fileAccessI.write(b,0,nRead); A$::|2~  
//if(nThreadID == 1) QY1|:(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PD:lI]:s  
} H4ancmy  
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Utility.log("Thread " + nThreadID + " is over!"); s{0c.
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bDownOver = true; Pbakw81!~  
//nPos = fileAccessI.write (b,0,nRead); A_|X54}w&  
} tE:6  
catch(Exception e){e.printStackTrace ();} mX@!O[f%9e  
} -JXCO<~k  
} l}9E0^AS  
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VCvFCyAz  
//打印回应的头信息 qW9~S0sl  
public void logResponseHead(HttpURLConnection con) PW"uPn  
{ "pQ)5/e  
for(int i=1;;i++) 2zbV9Bhq  
{ x I(X+d``  
String header=con.getHeaderFieldKey(i);  dm{/  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); }(w9[(K  
Utility.log(header+" : "+con.getHeaderField(header)); tP|ox]  
else UiN6-{v<2  
break;

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} h@D!/PS  
} SfGl*2  
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public void splitterStop() 4cJka~  
{ `SG8w_  
bStop = true; (L!#2Jy  
}  *#sY-Gd  
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} f9?f!k  
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/* )L$)qfQ~x  
**FileAccess.java 7;Vqr$9)  
*//文件访问(定位，写) 80Z'1'u0  
package NetFox; rLI);!^-  
import java.io.*; pXoT@[}  
n_P2l<F~/x  
&>
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public class FileAccessI implements Serializable{ G!5~`v  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }/.GB5Ej  
RandomAccessFile oSavedFile; [>LL  
long nPos; sx@%3j  
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public FileAccessI() throws IOException 3mLtnRX[m  
{ ]}>uvl^l  
this("",0); {7LN
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} :Wd@Qy?;  
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public FileAccessI(String sName,long nPos) throws IOException U$=#yg2 :  
{ Ec l/2  
oSavedFile = new RandomAccessFile(sName,"rw"); )|E617g  
this.nPos = nPos; )o_Pnq9_  
oSavedFile.seek(nPos); 1'BC R  
} `
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public synchronized int write(byte[] b,int nStart,int nLen) [IPXU9&Q  
{ 2#`9OLu8X  
int n = -1; cxn*!TwDs  
try{ !9vq"J~hz"  
oSavedFile.write(b,nStart,nLen); >4]y)df5  
n = nLen; [^eQGv[S  
} T6I$7F  
catch(IOException e) raB',Vp  
{ SuFGIb7E  
e.printStackTrace (); ,!oR"b!  
} o$KW*aDp  
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return n; &a?k1R>  
} GVUZn//  
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} y.Y;<UGu  
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/* ]@hN&W(+x  
**SiteInfoBean.java 7~m[:Eg6[s  
*/ v)%0`%nSR  
package NetFox; tDn:B$*}W,  
1Y(NxC0P=g  
4)NbQ[  
public class SiteInfoBean { ,<!v!~Iy  
Vl%UT@D|  
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private String sSiteURL; //Site's URL ]lZg }7h  
private String sFilePath; //Saved File's Path l3HfaCP6:  
private String sFileName; //Saved File's Name eR>|1s%^  
private int nSplitter; //Count of Splited Downloading File V&Q_iE  
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public SiteInfoBean() /uJ(&#87  
{//nSplitter的缺省值为5 ms`U,  
//default value of nSplitter is 5 BL1d=%2R  
this("","","",5); ;U]Ym48  
} *dPG[ }  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [SU;U['7  
{ k
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sSiteURL= sURL; .0?A0D?sP  
sFilePath = sPath;  {B7${AE  
sFileName = sName; uG=~kO  
this.nSplitter = nSpiltter; ~+CEek  
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} ,C}s8|@k  
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public String getSSiteURL() ;2[o>73F  
{ hkl9EVO)  
return sSiteURL; HJjx!7h  
} =;~*YD(%/  
#R*7y%cO  
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public void setSSiteURL(String value) =+w!fy  
{ (Q}ByX  
sSiteURL = value; usR+ZQaA  
} c;.jo?RR2  
"2z&9`VIY  
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public String getSFilePath()
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{ vE&K!k`  
return sFilePath; 9NeHN@D)  
} Y@ X>ejk"  
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public void setSFilePath(String value) r-$VPW  
{ /_1q)`NYy  
sFilePath = value; qFN`pe,  
} 8,-U`.  
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public String getSFileName() KpC!C9  
{ Of m0{c=  
return sFileName; @ )Nw>/;o  
} `wKd##v'@  
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public void setSFileName(String value) W#kd[Wi  
{ `PZcL2~E  
sFileName = value; TlD^EJG  
} OM?FpRVU8  
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public int getNSplitter() =HjC.h  
{ _o? I=UN2:  
return nSplitter; `t3w|%La}  
} LjCUkbzQF  
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public void setNSplitter(int nCount) W/<Lp+p  
{ 9D]bCi\  
nSplitter = nCount; S4VM(~,o  
} l'7'G$v  
} uc aa;zj  
>~jl0!2z@  
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/* lJdrrR)wg  
**Utility.java ai"N;1/1O|  
*/ 8Y [4JXUK  
package NetFox; v^aI+p6  
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public class Utility { QL:Qzr[  
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,*8)aZ1k  
public Utility() gO#%*  W  
{ F},kfCFF  
j{
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} {t|Q9
&  
=!u]t&yv  
//线程睡眠 gts09{"}Y  
public static void sleep(int nSecond) hISYtNWjd"  
{ )j!%`g  
try{ Cz6bD$5  
Thread.sleep(nSecond); .>1vN+  
} ?(M$r\\  
catch(Exception e) E:Ul_m8  
{ e5(c,,/  
e.printStackTrace (); .|0$?w  
} ^%O$7*  
} =R*IOJ  
p-*{x  
//日志 =^z*p9ZB  
public static void log(String sMsg) *onVG5<  
{ ; W$.>*O  
System.err.println(sMsg); .E;}.X  
} Ld 0j!II(  
|XmzqX%  
-Gjz+cRns  
public static void log(int sMsg) 4kR;K!@k  
{ Q)\[wYMt  
System.err.println(sMsg); 2V*;=cv~z  
} MAQ-'s@  
}
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,(f({l[J}  
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/* ~5>TMIDiuR  
**TestMethod.java bnN&E?{hF1  
*/ >M^:x-mib  
package NetFox; >sQf{uL  
q#K0EAgC  
mR$0Ij/v  
public class TestMethod { |h6,.#n  
vhzz(UPUt  

h+}{FB 29  
public TestMethod() =&PO_t5)z  
{ ///xx/weblogic60b2_win.exe SNf~%B?`L  
try{ 58R.`5B  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /Mj|Px%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iLNO}EUL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O^8=Xj#}  
fileFetch.start(); (yoF  
} ZCA= n  
catch(Exception e){e.printStackTrace ();} @2`nBtk  
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";^_[n
 
} 7Rd(,eWE@  
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goNDS5}  
public static void main(String[] args) 8:2Vib$  
{ uX6p^KNm5  
new TestMethod(); *VUJ);7k  
} UG4I@@=  
} IFW7MF9V  
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