http断点续传简单实现（java)

/* f@lRa>Z(Fm  
**SiteFileFetch.java {tn%HK">  
*/ N}Ozm6
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package NetFox; +~mBo+ ,  
import java.io.*; l}B,SkP^  
import java.net.*; 2ijw g~_@  
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public class SiteFileFetch extends Thread { j;@7
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SiteInfoBean siteInfoBean = null; //文件信息Bean z17  
long[] nStartPos; //开始位置 TZL)jfhj  
long[] nEndPos; //结束位置 >J>4g;Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象
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long nFileLength; //文件长度 6?OH"!b2-}  
boolean bFirst = true; //是否第一次取文件 !Ziq^o.  
boolean bStop = false; //停止标志 'V
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File tmpFile; //文件下载的临时信息 2}:scag  
DataOutputStream output; //输出到文件的输出流 [I:D\)$<  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） d[;=X.fZ2  
public SiteFileFetch(SiteInfoBean bean) throws IOException )TV4OT#  
{ AU@K5jwDwQ  
siteInfoBean = bean; zn|~{9>y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6'd=% V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); R4=n">>Q  
if(tmpFile.exists ()) i_T8Bfd:  
{ $>zLa_cn|  
bFirst = false; =BO} hk  
read_nPos();  13(JW  
} >i=^Mh-bm  
else RbUBKMZU  
{ +`g&J  
nStartPos = new long[bean.getNSplitter()]; Z7?C^m  
nEndPos = new long[bean.getNSplitter()]; }.w@. S"  
} Q-78B'!=  
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} >!:uVS  
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public void run() ZZqImB.Cz6  
{ )u~LzE]{_  
//获得文件长度 ]l.y/pRP5[  
//分割文件 :=x-b3U  
//实例FileSplitterFetch =BW>jD  
//启动FileSplitterFetch线程 ) 9h5a+Z  
//等待子线程返回 ':
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try{ KZ^W@*`D  
if(bFirst) '#d`K.;_b.  
{ V4p4m@z^u  
nFileLength = getFileSize(); hKP!;R  
if(nFileLength == -1) 2lPj%i 5  
{ 16=tHo8|  
System.err.println("File Length is not known!"); Z"rrbN1  
} G\3@QgyQ  
else if(nFileLength == -2) Xi3:Ok6FZ  
{ Ht#5;c2/  
System.err.println("File is not access!"); !DFT}eu  
} yAOYe"d  
else ((L=1]w  
{ "1P8[  
for(int i=0;i<nStartPos.length;i++) gE8p**LT+  
{ VE{[52  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); yZFm<_9>  
} [U[saR\  
for(int i=0;i<nEndPos.length-1;i++) #xZ7%   
{ \5.36Se  
nEndPos = nStartPos[i+1]; 3D>syf  
} LO
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nEndPos[nEndPos.length-1] = nFileLength; w7}m T3p,)  
} ]&%_Fpx  
} ta\AiHm  
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//启动子线程 hhQLld4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D>wq4u  
for(int i=0;i<nStartPos.length;i++) t~m >\(&  
{ V"=(I'X
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pX3Q@3,$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), mEsOYIu{  
nStartPos,nEndPos,i); Nb/W+& y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f,{O%*PUA  
fileSplitterFetch.start(); E'qGKT  
} >g8H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D.?Rc'yD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :^".cs?g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", luD.3&0n  
nEndPos = " + nFileLength); W.b?MPy]  
// fileSplitterFetch[nPos.length-1].start(); ^6Y4=  
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x#z}A&  
//等待子线程结束 (bnyT?p%  
//int count = 0; Z}74% 9qE  
//是否结束while循环 )`5kfj  
boolean breakWhile = false; YSi[s*.G  
_(=[d  
w_o|k&~,  
while(!bStop) M_@%*y\o  
{ 3B|?{U~  
write_nPos(); s"5f5Cn/Wh  
Utility.sleep(500); )i@j``P  
breakWhile = true; It.G-(  
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for(int i=0;i<nStartPos.length;i++) /7Z5_q_  
{ }S84^2
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if(!fileSplitterFetch.bDownOver) 9Qja|;  
{ CD|)TXy  
breakWhile = false; >D20f<w(H  
break; $|~YXH~O  
} f?)BAah  
} ?`R;ZT)U-  
if(breakWhile) LJ7Qwh_",  
break; <n+?7`d,  
)Zx;Z[  
#P[d?pY  
//count++;
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//if(count>4) 9 -7.4!]I  
// siteStop(); ~RdJP'YF-  
} !bEy~.  
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System.err.println("文件下载结束！"); 0N02E  
} D|`O8o?)  
catch(Exception e){e.printStackTrace ();} nlv8HC  
} CMk0(sztU_  
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q)S70M_1  
//获得文件长度 x;d*?69f]  
public long getFileSize() bF'Y.+"dr  
{ C4vmgl&  
int nFileLength = -1; 3|1ug92  
try{ $#q:\yQsPC  
URL url = new URL(siteInfoBean.getSSiteURL()); .~J}80a/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dUAZDoLi  
httpConnection.setRequestProperty("User-Agent","NetFox"); :oRR1k  
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int responseCode=httpConnection.getResponseCode(); J,@SSmJ`  
if(responseCode>=400) "[W${q+0x  
{ s^:8bFn9$  
processErrorCode(responseCode); v
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return -2; //-2 represent access is error vFuf{ @P  
} )*!"6d)^  
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String sHeader; j*2Q{ik>J  
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for(int i=1;;i++) !V|%n(O"  
{ v X=zqV  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
5}J|YKyP  
//Utility.log(in.readLine()); 34k}7k~n  
sHeader=httpConnection.getHeaderFieldKey(i); )a:j_jy  
if(sHeader!=null) _ U/[n\oC  
{ R+}x#  
if(sHeader.equals("Content-Length")) \^=Wp'5R  
{ p'# (^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); rl#[HbPM  
break; 46U?aHKW@|  
} "Me)'  
} CUz1q*):  
else Snm m(.  
break; P<&-8QA  
} jkz.qo-%  
} :)/%*<vq,  
catch(IOException e){e.printStackTrace ();} ~hYTs  
catch(Exception e){e.printStackTrace ();} 8^/V2;~^,>  
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Utility.log(nFileLength); O0|**Km\+  
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return nFileLength; G-5wv  
} kVu8/*Q  
h!c6]D4!L  
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//保存下载信息（文件指针位置） 2L=+z1%I  
private void write_nPos() pVuJ4+`  
{ }d<x
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try{ p.Y
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output = new DataOutputStream(new FileOutputStream(tmpFile)); p1zT]  
output.writeInt(nStartPos.length); wW5:p]<Y  
for(int i=0;i<nStartPos.length;i++) Jptzc:~B  
{ B.:DW3  
// output.writeLong(nPos); (wxdT6RVm\  
output.writeLong(fileSplitterFetch.nStartPos); `gI`Cq4  
output.writeLong(fileSplitterFetch.nEndPos); g~zz[F 8U  
} z&a%_ ]Q*  
output.close(); !rmXeN]-r  
} }B-@lbK6)  
catch(IOException e){e.printStackTrace ();} ;'^5$q  
catch(Exception e){e.printStackTrace ();} 3$cIm+  
} >0#WkmRY  
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//读取保存的下载信息（文件指针位置） \W"N{N  
private void read_nPos() qs$%/  
{ Gp}:U>V)  
try{ #;4afj:2g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8|:bis~wm  
int nCount = input.readInt();
)(&Z&2~A  
nStartPos = new long[nCount]; gY)NPi}!`  
nEndPos = new long[nCount]; f>g<:.k*  
for(int i=0;i<nStartPos.length;i++) f-Yp`lnn.d  
{ ym>>5(bni  
nStartPos = input.readLong(); XaFu(Xu7  
nEndPos = input.readLong(); >.P/fnvJ  
} )s @}|`  
input.close(); k91ctEp9>  
} -!X,MDO  
catch(IOException e){e.printStackTrace ();} T6 K?Xr{_  
catch(Exception e){e.printStackTrace ();} os=Pr{  
} -,;r %7T  
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private void processErrorCode(int nErrorCode) < 5%:/j  
{ <<xUh|zE  
System.err.println("Error Code : " + nErrorCode); B/P E{ /  
} AsBep  
*rs@6BSj  
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//停止文件下载 xG802?2i/;  
public void siteStop() {J`]6ba  
{
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bStop = true; LyEM^d]  
for(int i=0;i<nStartPos.length;i++) .}AzkKdd@  
fileSplitterFetch.splitterStop(); I-@A{vvPK  
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} +`;YK7o  
} u}zCcWP|L  
//负责部分文件的抓取 ]Q?`|a+i  
**FileSplitterFetch.java H9d!-9I  
*/ DK!QGATh  
package NetFox; BhO*Pfs  
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import java.io.*; 0+a-l[!p  
import java.net.*; ;<aT|4  
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public class FileSplitterFetch extends Thread { 5"x=kp>!d  
s7x&x;-  
8M{-RlR  
String sURL; //File URL qs96($  
long nStartPos; //File Snippet Start Position .XD.'S  
long nEndPos; //File Snippet End Position RnvPqNs  
int nThreadID; //Thread's ID oCl $ 0x  
boolean bDownOver = false; //Downing is over QkEIV<T&)l  
boolean bStop = false; //Stop identical z#$>f*b  
FileAccessI fileAccessI = null; //File Access interface PL+j;V(<  
L4fM?{Ic:s  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z*9Qeu-N:  
{ {8'f>YP  
this.sURL = sURL; J(k\Pz*  
this.nStartPos = nStart; ?`m#Y&O
i  
this.nEndPos = nEnd; <ptskbu  
nThreadID = id; l%$~X0%DM  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xq U@87[_  
} {FIr|R&  
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public void run() i,[
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{ )oEHE7y  
while(nStartPos < nEndPos && !bStop) 75u5zD   
{ 4Nz@s^9  
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try{ : h"Bf@3  
URL url = new URL(sURL); {8!\aYI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R2]2#3`  
httpConnection.setRequestProperty("User-Agent","NetFox"); jH4,-  
String sProperty = "bytes="+nStartPos+"-"; Hr?_`:  
httpConnection.setRequestProperty("RANGE",sProperty); /< OoZf+[  
Utility.log(sProperty); aP#nK  
k9V#=,K0  
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InputStream input = httpConnection.getInputStream(); 8'niew 5d  
//logResponseHead(httpConnection); +3;`4bW  
cip"
9|"  
{LwV&u(  
byte[] b = new byte[1024]; .u+ZrA#  
int nRead; :A~6Gk92A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +prr~v
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{ 3RwDIk?>%  
nStartPos += fileAccessI.write(b,0,nRead); V^v?;f?  
//if(nThreadID == 1) f WUFCbSU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z5V~m_RO  
} ?+Q?K30:  
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Utility.log("Thread " + nThreadID + " is over!"); #@quuiYq  
bDownOver = true; w1#1s|  
//nPos = fileAccessI.write (b,0,nRead); -&AgjzN!  
} 12D>~#J  
catch(Exception e){e.printStackTrace ();} 
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} u$vA9g4  
} 4
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//打印回应的头信息 +>w %j&B  
public void logResponseHead(HttpURLConnection con) '@jP$6T&  
{ D-v}@tS'  
for(int i=1;;i++) M,uQ8SZA[  
{ v;%>F)I  
String header=con.getHeaderFieldKey(i); d*M:PjG@  
if(header!=null) C(4r>TNm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /t4#-vz  
Utility.log(header+" : "+con.getHeaderField(header)); T@Q,1^?i  
else vs*Q
{  
break; ##_`)/t,  
} 1N3qMm^  
} ^V5VRGq  
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Te\i;7;4u  
public void splitterStop() lR
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{ /=+y[y3`  
bStop = true; 53g(:
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} `oPUf!  
vv 
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} @(b;H0r~  
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>j%4U*  
/* km 0LLYG  
**FileAccess.java =!V
-V}KK-  
*//文件访问(定位，写) eu^B  
package NetFox; "
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import java.io.*; 5s /fBS  
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public class FileAccessI implements Serializable{ Ub"6OT1tl  
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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 4^OPzg6Z%p  
RandomAccessFile oSavedFile; 8|U-{"!O?  
long nPos; 0q!
  
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public FileAccessI() throws IOException UtpK"U$XOU  
{ R9-Ps qmF  
this("",0); 3-%F)@n  
} ML)5nJD  
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s|q
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public FileAccessI(String sName,long nPos) throws IOException #_U[
T  
{ Z1&<-T_  
oSavedFile = new RandomAccessFile(sName,"rw"); u/,ng&!  
this.nPos = nPos; gf]k@
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oSavedFile.seek(nPos); H
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} fxcCz 5  
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public synchronized int write(byte[] b,int nStart,int nLen) +{7/+Zz  
{ ;_TPJy  
int n = -1; vIK+18v7  
try{ 7)FI_uW  
oSavedFile.write(b,nStart,nLen); Y/Dah*  
n = nLen; ~4}'R_  
} 8b!-2d:*  
catch(IOException e) f:!b0j  
{ U~nW>WJ+.  
e.printStackTrace (); 2Jl
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} EPn0ZwnS:M  
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{~=Z%Cj2Q  
return n; BT3X7Cx  
} eGEeWJ}[$  

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} =]Vrl-a`^  
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/* ~d)2>A2:  
**SiteInfoBean.java @qaK5  
*/ vf&Sk
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package NetFox; ]y52%RAKI  
'(S@9%,aK1  
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public class SiteInfoBean { ;v=v4f'+  
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private String sSiteURL; //Site's URL qz]g4hS  
private String sFilePath; //Saved File's Path nN|1cJ'.Fk  
private String sFileName; //Saved File's Name `{ 6K~(  
private int nSplitter; //Count of Splited Downloading File jeLC)lQ*  
{YT@$K]w,  
!92zC._  
public SiteInfoBean() c1CUG1i  
{//nSplitter的缺省值为5 mY& HK)  
//default value of nSplitter is 5 [$+N"4  
this("","","",5); &nXa/XIZ_  
} CEMe2~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u&7c2|Q  
{ JPt0k  
sSiteURL= sURL; x]X!nx6G  
sFilePath = sPath; {r.yoI4e  
sFileName = sName; 9[7Gxmf  
this.nSplitter = nSpiltter; "
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Pm}
 
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} _=s{,t &u  
q n2X._`  
^CtA@4  
public String getSSiteURL() 6%8,OOS  
{ ~,: FZ1wh  
return sSiteURL; gb,X"ODq  
} g5,Bj
  
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public void setSSiteURL(String value) _w\A=6=q|  
{ a{deN9Qn  
sSiteURL = value; =4H"&Eu{  
} Hb:@]!r>  
{ :~&#D  
#383W)n  
public String getSFilePath() IBY(wx[5S  
{ hiM nU  
return sFilePath; tPb$ua|  
} B[8`l} t  
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public void setSFilePath(String value) A@I( &Z  
{ C2/B1ba  
sFilePath = value; }vGWlNd#g  
} %=t8   
4#c-?mh_  
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public String getSFileName() Vr1yj  
{ zG0191f  
return sFileName; q8_8rp-@  
} <JyF5  
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public void setSFileName(String value) x6BO%1  
{ @9X+ BdQU  
sFileName = value; 'U8% !  
} o7A+O%dX  
F4xXJ"vc  
^o@N.+`&<  
public int getNSplitter() u#&ZD|  
{ =,4iMENm!  
return nSplitter; X":T>)J-  
} FO/[7ZH  
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{*jo,<4ee  
public void setNSplitter(int nCount) o8A1cb4<T  
{ D+u#!t[q  
nSplitter = nCount; X\yy\`o  
} 4sCzUvI~Y1  
} Dno'-
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#@cOyxUt  
/* )^^Eh=Kbj  
**Utility.java $afE= qC*  
*/ E/6@>.T?'  
package NetFox; q]qKU`m!Q`  
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public class Utility { [IgB78_$  
^ rB7&96C,  
2[;4D/`*  
public Utility() GqT0SP  
{ jLy3c@Dp  
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ee+*&CT)  
} <PayP3E
 
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//线程睡眠 d>f.p"B.gj  
public static void sleep(int nSecond) 0kp#+&)+  
{ >cE@m=[  
try{ .e,(}_[[<  
Thread.sleep(nSecond); A3#^R%2)W  
} bx5f\)  
catch(Exception e) 3r[}'ba\  
{ NPFrn[M$  
e.printStackTrace (); R;{y]1u  
} r-,P  
} "iC*Eoz#.  
j18qY4Gw)  
//日志 \`!M5FJ  
public static void log(String sMsg) @2>j4Sc  
{ \
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System.err.println(sMsg); REe<k<>p~  
} >Wbt_%dKy  
~$PQ8[=  
s:fy *6=[Z  
public static void log(int sMsg) MBO3y&\S4  
{ '0juZ~>}  
System.err.println(sMsg); TO|&}sDh  
} u0M? l  
} GF3"$?Cw  
vp>,}nx4  
g3`:d)|  
/* 4.^1D';(  
**TestMethod.java D@]*{WO  
*/ {r$n $  
package NetFox; fF"\$Ny  
<A_LZi  
$<~o,e-4  
public class TestMethod { oOU?6nq  
fF\s5f#:  
)U~,q>H+ %  
public TestMethod() %~`y82r6  
{ ///xx/weblogic60b2_win.exe >C1**GQ  
try{ zh<[/'l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); eVVm"96Q.;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xXJl Qbs  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PZDj)x_%B&  
fileFetch.start(); S5W*,?  
} rerl-T<3  
catch(Exception e){e.printStackTrace ();} (q@DBb4  
)G a%Eg9  
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} UZ`GS$D@  
+-VkRr#  
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public static void main(String[] args) wTL&m+xr  
{ ZE!dg^-L  
new TestMethod(); )Ycjx~   
} Wd R~  
} Q|O! cEW/  
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