http断点续传简单实现（java)

/* mQ^SpK #  
**SiteFileFetch.java -mG
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*/ R#HX}[Hb  
package NetFox; cs*"9nKl  
import java.io.*; `a9iq>   
import java.net.*; il$eO 7
 
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public class SiteFileFetch extends Thread { Sn[/'V^$a  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (
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long[] nStartPos; //开始位置 a( SJ5t?-2  
long[] nEndPos; //结束位置 oH(=T/{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P 4+}<5  
long nFileLength; //文件长度 ^n*:zmD  
boolean bFirst = true; //是否第一次取文件 c uHF^l  
boolean bStop = false; //停止标志 ^#4Ah[:XA  
File tmpFile; //文件下载的临时信息 Oe lf^&m  
DataOutputStream output; //输出到文件的输出流 <yw56{w,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zEi\#Zg$  
public SiteFileFetch(SiteInfoBean bean) throws IOException aq- |  
{ xpBQ(6Y  
siteInfoBean = bean; q$'[&&_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); u]&+TR  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); eZ{Ce.lNR  
if(tmpFile.exists ()) bmO(tQS$5  
{ r\FduyOXv  
bFirst = false; DSK?7F$_oE  
read_nPos(); 3(_:"?xA  
} ,6SzW+L7  
else Ht|"91ZC5  
{ :}-izd)/j  
nStartPos = new long[bean.getNSplitter()];  C
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nEndPos = new long[bean.getNSplitter()]; ff 6x4t  
} 3)hQT-)  
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} +g_m|LF  
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public void run() !1Nh`FN  
{ r(JP& @  
//获得文件长度 '~zi~Q7M  
//分割文件 q2*1Gn9!j  
//实例FileSplitterFetch $J#Z`%B^y  
//启动FileSplitterFetch线程 ,@\z{}~v  
//等待子线程返回 e<+b?@}=B  
try{ -?NAA]P5c@  
if(bFirst) \s7/`  
{ /4KHf3Nr  
nFileLength = getFileSize(); &FWz7O>1  
if(nFileLength == -1) DC0ON`  
{ ?*'0;K13  
System.err.println("File Length is not known!"); K?>sP%m)  
} 9(lcQuE9  
else if(nFileLength == -2) RV%)~S@!R  
{ sW
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System.err.println("File is not access!"); ?0+N  
} svtqX-Vj"  
else ?%$~Bb _  
{ Q+s2S>U{v  
for(int i=0;i<nStartPos.length;i++) d '\^S}  
{ 0 gR_1~3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^0?ww&X  
} v ,zD52  
for(int i=0;i<nEndPos.length-1;i++) 15d'/f  
{ -K/c~'%'*  
nEndPos = nStartPos[i+1]; f6 s .xQ  
} 9U Hh#  
nEndPos[nEndPos.length-1] = nFileLength; *bUOd'vh  
} gyxC)br  
} p$cb&NNh*H  
i!iG7X)qT  
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//启动子线程 c-U]3`;Q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U^]@0vR  
for(int i=0;i<nStartPos.length;i++) c
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{ J+}z*/)|#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oWEzzMRz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), m]c1DvQb  
nStartPos,nEndPos,i); Hz%<V*\{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r 5t{I2  
fileSplitterFetch.start(); 4RfBXVS  
} = BbG2k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >ByqM{?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); aLlHR_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @WiTh'w0  
nEndPos = " + nFileLength); @r(3   
// fileSplitterFetch[nPos.length-1].start(); w+a5/i@  
$LiBJ~vV<  
dV
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//等待子线程结束 KyBtt47\  
//int count = 0; 8Wgzca Q*  
//是否结束while循环 /T+%q#4  
boolean breakWhile = false; btBu[;  
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while(!bStop) uPE Ab2u="  
{ p{+F{e  
write_nPos(); 8C@6 b4VK  
Utility.sleep(500); .9?GKD  
breakWhile = true; .o]9 HbIk5  
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for(int i=0;i<nStartPos.length;i++) U>@AE  
{ u"m TS&  
if(!fileSplitterFetch.bDownOver) BCtKxtbS  
{ f?> ?jf  
breakWhile = false; &.qLE  
break; 6C/Pu!Sx?  
} oTrit_@3  
} mP's4  
if(breakWhile) BqUwvB4  
break; t+
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//count++; 6cD3(//  
//if(count>4) ^f9@=I  
// siteStop(); /:"^,i\t  
} ]c bXI  
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System.err.println("文件下载结束！"); e X6o7a  
} Q<KF<K'0hg  
catch(Exception e){e.printStackTrace ();} GMB3`&qh  
} ewWw  
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//获得文件长度 W|"bV 6d3  
public long getFileSize() 1(RRjT9  
{ I:6
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int nFileLength = -1; eu":\ks  
try{ Z?V vFEt%  
URL url = new URL(siteInfoBean.getSSiteURL()); <PM.4B@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U@D\+T0  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1/&^~'  
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int responseCode=httpConnection.getResponseCode(); B I=57  
if(responseCode>=400) !;P[Y"h@r  
{ 0d1!Q!PH3  
processErrorCode(responseCode); S!b?pl  
return -2; //-2 represent access is error o{QV'dgu  
} >[:qJ|i%  
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_!Pi+l4p/}  
String sHeader; D7muf  
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for(int i=1;;i++) ,~DKU*A_~  
{ )u4=k
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2%9L'-  
//Utility.log(in.readLine()); U"oHPK3"TA  
sHeader=httpConnection.getHeaderFieldKey(i); )rlkQ'DN  
if(sHeader!=null) QpRk5NeLe  
{ H9(UzyN>i  
if(sHeader.equals("Content-Length")) f2&6NC;  
{ 5.DmMG[T^=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2%J] })  
break; 06Q9X!xD  
} s^4wn:*$zd  
} `^ a:1^  
else teC/Uf5  
break; :Nwv&+  
} ` N R,8F  
} Q7{{r&|t&  
catch(IOException e){e.printStackTrace ();} s,kY12<7m  
catch(Exception e){e.printStackTrace ();} p=#/H,2  
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Utility.log(nFileLength); _8-T?j**   
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return nFileLength; Qr7|;l3  
}
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7I@df.rf6J  
//保存下载信息（文件指针位置） {v|ib112;  
private void write_nPos() F!Cn'*  
{ <a&xhG}  
try{ _HjB'XNr(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); SuNc&e#(  
output.writeInt(nStartPos.length); BwGOn)KL  
for(int i=0;i<nStartPos.length;i++) ksOc,4A  
{ R y(<6u0  
// output.writeLong(nPos); B&<5VjZ\  
output.writeLong(fileSplitterFetch.nStartPos); MgN;[4|[h  
output.writeLong(fileSplitterFetch.nEndPos); Xwjm T  
} V~Z)
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output.close(); b?VByJl  
} 7/_|/4&  
catch(IOException e){e.printStackTrace ();}
;!lwB  
catch(Exception e){e.printStackTrace ();} a=x&sz\x  
} dmcY]m  
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//读取保存的下载信息（文件指针位置） VS_\bIC  
private void read_nPos() q?)5yukeF  
{ [O|c3;  
try{ Qh6vH9(D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3)9e-@  
int nCount = input.readInt(); !'IZr{Y>  
nStartPos = new long[nCount]; 0NU3% 4?  
nEndPos = new long[nCount]; )OucJQ  
for(int i=0;i<nStartPos.length;i++) 9}Za_ZgG  
{ @g]+$Yj  
nStartPos = input.readLong(); \2#K {  
nEndPos = input.readLong(); 6}0_o[23  
} ( ]0F3@k#s  
input.close(); vb]uO ' l  
} q[}re2
 
catch(IOException e){e.printStackTrace ();} 2V$Jn8v,`{  
catch(Exception e){e.printStackTrace ();} Ey%[t  
} .sOZ"=tW  
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g\?07@Zd|  
private void processErrorCode(int nErrorCode) g 4|ai*^  
{ ygX!'evY  
System.err.println("Error Code : " + nErrorCode); ,
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} ;-l^X%r  
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heB![N0:  
//停止文件下载 2']0c z  
public void siteStop() qu]a+cYY  
{ 
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bStop = true; R/Sm  
for(int i=0;i<nStartPos.length;i++) [u J<]  
fileSplitterFetch.splitterStop(); TDy)A2Z  
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} _ouZd.
 
} | z_av  
//负责部分文件的抓取 Ol<LL#<j4  
**FileSplitterFetch.java =knLkbiq7,  
*/ YcR: _ac  
package NetFox; nw_|W)JVQ  
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import java.io.*; Z![#Uz.z  
import java.net.*; aHI~@  
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public class FileSplitterFetch extends Thread { 3UZ_1nY  
4`cfFowK~  
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String sURL; //File URL NNTrH\SU#  
long nStartPos; //File Snippet Start Position wdV)M?  
long nEndPos; //File Snippet End Position 0"
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int nThreadID; //Thread's ID QJ>=a./  
boolean bDownOver = false; //Downing is over hp}rCy|01  
boolean bStop = false; //Stop identical {!{T,_ J  
FileAccessI fileAccessI = null; //File Access interface /X#OX8gb]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mUR[;;l  
{ ?duw0SZ  
this.sURL = sURL;
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this.nStartPos = nStart; Vhb~kI!x  
this.nEndPos = nEnd; b}u#MU  
nThreadID = id; 66+]D4(k  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9)j"|5H  
} J4iu8_eH!D  
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public void run() wLt0Fq6QG  
{ 99]s/KD2yb  
while(nStartPos < nEndPos && !bStop) KVViTpZ  
{ y^kC2DS   
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try{ !y!s/i&P%  
URL url = new URL(sURL); K
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6Q+VW_~  
httpConnection.setRequestProperty("User-Agent","NetFox"); !ueh%V Ky  
String sProperty = "bytes="+nStartPos+"-"; ?6I`$ &OA  
httpConnection.setRequestProperty("RANGE",sProperty); BP4vOZ0$  
Utility.log(sProperty); ?o/p}6  
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InputStream input = httpConnection.getInputStream(); to#2.  
//logResponseHead(httpConnection); F0r5$Pl*  
@e7_&EGR?  
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byte[] b = new byte[1024]; xcJvXp  
int nRead; [ei5QSL |  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I9U 8@e!X  
{ qzo)\,  
nStartPos += fileAccessI.write(b,0,nRead); `<Hc,D; p  
//if(nThreadID == 1) #SD2b,f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gt!Hm(  
} : B1 "=ly  
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Utility.log("Thread " + nThreadID + " is over!"); )_kEy>YscZ  
bDownOver = true; 8@T0]vH&  
//nPos = fileAccessI.write (b,0,nRead); G~Y#l@8M+  
} f\~w!-  
catch(Exception e){e.printStackTrace ();} xu;^F  
} PM {L}tEQ  
} :X*uE^bH  
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y92<(ziaX)  
//打印回应的头信息 >4#\ U!  
public void logResponseHead(HttpURLConnection con) u9+)jN<Yh  
{ jar?"o  
for(int i=1;;i++) mj9]M?]  
{ X<1ymb3  
String header=con.getHeaderFieldKey(i); [F
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if(header!=null) L;KL
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9@*4^Ks p  
Utility.log(header+" : "+con.getHeaderField(header)); -OfAl~ 4  
else UB%;P-RD  
break; `WQpGBS_z_  
} lw4#C`bx  
} 6b!1j,\Vx  
|txzIc.#  
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public void splitterStop() Yt4v}{+  
{ )IE)a[wo  
bStop = true; *I9G"R8  
} VC!g,LU|-  
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} 6|%HCxWO  
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/* \l 3M\$oS>  
**FileAccess.java |e3YTLsI  
*//文件访问(定位，写) RWn#"~  
package NetFox; MpJx>
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import java.io.*; [@s5v  
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public class FileAccessI implements Serializable{ k_%maJkXp  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 l02aXxT)]  
RandomAccessFile oSavedFile; P$
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long nPos; W8!8/IZbN  
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public FileAccessI() throws IOException @gJPMgF$F  
{ aII:Pzh]B  
this("",0); @;d7#!:cE  
} NMP*q @  
sM%.=
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public FileAccessI(String sName,long nPos) throws IOException \G1(r=fU  
{ DRi/<  
oSavedFile = new RandomAccessFile(sName,"rw"); nL!nzA  
this.nPos = nPos; `3F/7$q_  
oSavedFile.seek(nPos); q
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} *(<3 oIRS  
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~


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public synchronized int write(byte[] b,int nStart,int nLen) k+cHx799  
{ cGjkx3l*  
int n = -1; eD 7Rv<  
try{ Z?'){\$*  
oSavedFile.write(b,nStart,nLen); knZ<V%/e  
n = nLen; 1uhSP!b  
} i'vjvc~   
catch(IOException e) Q|cA8Fn  
{ Ad`jV_z  
e.printStackTrace (); 1Aa=&B2  
} Yy0m &3[  
<8/lHQ^\)  
w+tO@  
return n; rx;zd?  
} k$} 6Qd  
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} ~# |p=Y  
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/* \(ZOt.3!J  
**SiteInfoBean.java t\C[mw  
*/ YY<e]CriU  
package NetFox; Q /\Hc  
K?+Rq  
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public class SiteInfoBean { .c.#V:XZ#U  
v|mZcAz  
c}FZb$q#  
private String sSiteURL; //Site's URL Yt;.Z$i ,  
private String sFilePath; //Saved File's Path tI(co5 W  
private String sFileName; //Saved File's Name .{W)E  
private int nSplitter; //Count of Splited Downloading File sWnU*Q  
YEqWTB|w  
^KMZB  
public SiteInfoBean() U9B|u`72  
{//nSplitter的缺省值为5 %Gs!oD  
//default value of nSplitter is 5 /=qn1  
this("","","",5); >j$CM:w  
} \D #NO  
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=>6'{32W_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 89)rss  
{ Y,@{1X`0@3  
sSiteURL= sURL; I2'UC) 0  
sFilePath = sPath; AHR%3W  
sFileName = sName; `p%&c%*A  
this.nSplitter = nSpiltter; $Mp#tH28  
4m6E~_:F  
zKk2>.  
} g< {jgF  
bXiT}5mJU  
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public String getSSiteURL() zW^@\kB0D  
{ NUH#  
return sSiteURL; /P0%4aWu=  
} cv["Ps#;`W  
aNCIh@m~  
Ol24A^  
public void setSSiteURL(String value) ,#r>#fi0  
{ ""ICdZ_A  
sSiteURL = value; PZ"=t!  
} 9
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.r?-O{2t  
7=8e|$K_  
public String getSFilePath() ZWSYh>"  
{ OE/O:F:1j  
return sFilePath; HLU'1As65  
} JQ8wL _C>  
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d1#;>MiU  
public void setSFilePath(String value) ~8Z0{^  
{ :_Y@,CpIEg  
sFilePath = value; GKwm %A  
} PDo%ob\Ym  
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*eytr#0B-  
public String getSFileName() [x5T7=  
{ x,z+l-y  
return sFileName; NQ!jkojD  
} q8.K-"f(Q  
MDS;qZx=  
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public void setSFileName(String value) Nq)=E[$  
{ TCFx+*fBd  
sFileName = value; ^l6q  
} -lm\~VZT3  
W9?Vh{w  
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public int getNSplitter() {ls$#a+d  
{ gfs?H#  
return nSplitter; +I7n6s\  
} &/4W1=>(  
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ucyz>TL0  
public void setNSplitter(int nCount) FMuM:%&J]  
{ {|6(_SM|  
nSplitter = nCount; l=ZhHON  
} Dm[4`p@IY\  
} ]w(i,iJ  
A -G?@U  
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/* t+5JIQY>  
**Utility.java RJ1Q.o  
*/ -1~bWRYq  
package NetFox; d:6?miMH]t  
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public class Utility { m0W5Ogk  
Zycu3%JI  
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public Utility() w3c[t~R8  
{ DJ;G0*  
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b}p0&%I
 
} ^PfFW  
[Zk|s9  
//线程睡眠 PWOV~`^;  
public static void sleep(int nSecond) e7ixi^Q  
{ G@anY=D\EB  
try{ )%U&z>^P  
Thread.sleep(nSecond); 9Nglt3J
[  
} <1VzQH!o  
catch(Exception e) 1_THBL26d  
{ oBQr6-nZ  
e.printStackTrace (); 4,T!zT6&  
} E@aR5S>  
} %zyO}  
_* ]~MQ=  
//日志 n3-u.Fb  
public static void log(String sMsg) PBb@J'b  
{ >n)N=Zyu  
System.err.println(sMsg); J.mEOo!>  
} HjV3PFg  
-4o6OkK<  
.OVIQxf  
public static void log(int sMsg) nM1U=Du  
{ BDyOX6  
System.err.println(sMsg); E% Ce/n  
} nk]jIRy^T  
} Z+@"  
2P~zYdjS  
M;={]w@n  
/* b2. xJ4  
**TestMethod.java ]L%qfy4  
*/ Q2iS0#  
package NetFox; aHe/MucK  
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a-,!K  
public class TestMethod { !-%i" a  
+Cl(:kfYB  
ZkkXITQkPM  
public TestMethod() @kn0f`  
{ ///xx/weblogic60b2_win.exe ^)conSm  
try{ 5V4Z
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); z,[4BM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9~bje^M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); g= k}6"F~  
fileFetch.start(); 2c@R!*  
} 5bR;R{:x  
catch(Exception e){e.printStackTrace ();} f@Rn&&-  
:f?\ mVS+  
mdR:XuRD"t  
} |S|0'C*  
~T9%%W[  
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public static void main(String[] args) E$; =*0w  
{ I4ZL+a  
new TestMethod(); \1hbCv$Hf  
} u{
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} k:Sxs+)?1  
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