http断点续传简单实现（java)

/* J?J4<l9  
**SiteFileFetch.java vi^YtA  
*/ (c)/&~aE  
package NetFox; tkHmH/'7  
import java.io.*; oX:&;KA  
import java.net.*; ZYWGP:Y  
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public class SiteFileFetch extends Thread { _h^.`Tz,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean kEC^_sO"  
long[] nStartPos; //开始位置 "*<vE7  
long[] nEndPos; //结束位置 t adeG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 V~KWy@7  
long nFileLength; //文件长度 f?/OV*  
boolean bFirst = true; //是否第一次取文件 >qNpY(Ql  
boolean bStop = false; //停止标志 Wfd`v  
File tmpFile; //文件下载的临时信息 H ;=^ W  
DataOutputStream output; //输出到文件的输出流 #6|ve?`I  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Cn5"zDK$  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;E 9o%f:o  
{ HoAg8siQ  
siteInfoBean = bean; Pd&KAu|<`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )-5eIy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )-[$m%  
if(tmpFile.exists ()) \\:%++}J  
{ 5`fUR/|[  
bFirst = false; zo@vuB.  
read_nPos(); vv,<#4d
 
} QAxy?m,'  
else %XukiA+  
{ KH?6O%d  
nStartPos = new long[bean.getNSplitter()]; }[
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nEndPos = new long[bean.getNSplitter()]; sz270k%[  
} U=KUx  
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} ~
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public void run() Z+U -+eG  
{ ',`Qx{tQ)  
//获得文件长度 aE)1LP  
//分割文件 `)8~/G%  
//实例FileSplitterFetch _GxC|d  
//启动FileSplitterFetch线程 w=_^n]`R  
//等待子线程返回 5TpvJ1G  
try{ .yfp-n4H  
if(bFirst) $s}w23nB  
{ 3AdYZ7J  
nFileLength = getFileSize(); "ADI.  
if(nFileLength == -1)  YC6guy>  
{ T;BFO5G@  
System.err.println("File Length is not known!"); LbJf5xdi  
} 2Cy,#X%j>  
else if(nFileLength == -2)
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{ ?`xF>P]M  
System.err.println("File is not access!"); N,XjZ26  
} @Hp%4$=  
else x[TLlV:{  
{ WxYEu+_  
for(int i=0;i<nStartPos.length;i++) YJ,"@n_  
{ iNkN'("  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  ~ e?af  
} QlB9m2XB  
for(int i=0;i<nEndPos.length-1;i++) FXT^r3  
{ +p>h` fc  
nEndPos = nStartPos[i+1]; BhAT@%  
} 2 ^"j]g>mj  
nEndPos[nEndPos.length-1] = nFileLength; ,(h-  
} -?#iPvk6  
} o9|
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|(W04Wp"@  
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//启动子线程 l*hWws[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2>X yrG  
for(int i=0;i<nStartPos.length;i++) mgH~G
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{ T$0)un  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A405igF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  #9
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nStartPos,nEndPos,i); z0\ $#r^I  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tQNc+>7k+u  
fileSplitterFetch.start(); AEj%8jh  
} RrBG=V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5!'1;GLs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ms5qQ<0v_  
nEndPos = " + nFileLength); $s1/Rmw  
// fileSplitterFetch[nPos.length-1].start(); Q}\\0ajS)  
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//等待子线程结束 ;lE=7[UJ3X  
//int count = 0; #E Bdg  
//是否结束while循环 u!~kmIa4  
boolean breakWhile = false; rd%uc~/  
Z
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while(!bStop) _nz_.w0H9  
{ ,<P"\W  
write_nPos(); Q'^'G>MBJ  
Utility.sleep(500); )d3C1Pd>  
breakWhile = true; sbVEA  
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for(int i=0;i<nStartPos.length;i++) }sqFvab<  
{ /,~]1&?}1  
if(!fileSplitterFetch.bDownOver) ,f)+|?wz  
{ X6B,Mply  
breakWhile = false; Qh8pOUD0l}  
break; p3-~cr.LD  
} "h1ek*(?<  
} %$b}o7U"s  
if(breakWhile) UzSDXhzObf  
break; /#{~aCOi)  
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$;=^|I4E  
//count++; ktfxb<%  
//if(count>4) '-f` 5X  
// siteStop(); _&gO>G,uy  
} wpN [0^M-0  
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System.err.println("文件下载结束！"); cr0/.Zv)  
} Q: -&
  
catch(Exception e){e.printStackTrace ();} 80%"2kG  
} E*T6kp^b  
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QYDI-<.(  
//获得文件长度 5G2ueRVb  
public long getFileSize() $SA @ "  
{ 5IzCQqOPgX  
int nFileLength = -1; 4Hyp]07  
try{ l_04b];  
URL url = new URL(siteInfoBean.getSSiteURL()); L?a4>uVY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZBU<L+#  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8N j}  
3zfiegY@wm  
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int responseCode=httpConnection.getResponseCode(); p[|V7K'Z  
if(responseCode>=400) =kq<J-:#R  
{ "IJ1b~j?  
processErrorCode(responseCode); peS4<MqWu  
return -2; //-2 represent access is error %(%EEt  
} P^q!Pye  
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String sHeader; -`spu)  
c*
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for(int i=1;;i++) (yEU9R$I"  
{ J7EWaXGbz  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &C9)%5O)  
//Utility.log(in.readLine()); 0#Q]>V@rO4  
sHeader=httpConnection.getHeaderFieldKey(i); 9w0v?%%_  
if(sHeader!=null) meap;p  
{ BdvpG  
if(sHeader.equals("Content-Length")) A2PeI"y  
{ $_a/!)bP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ??hKsjNAm0  
break; mH<|.7~0  
} F2n4#b  
} #{)mr [c|  
else Qe9}%k6@E  
break; -4J.YF>  
} vON7~KA  
} %vG;'_gMB  
catch(IOException e){e.printStackTrace ();} tB}W )Eb  
catch(Exception e){e.printStackTrace ();} VqOTrB1w/  
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Utility.log(nFileLength); =(,kjw88w  
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return nFileLength; _$}@hD*R~  
} g'-hSV/@}@  
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0*uJS`se6Z  
//保存下载信息（文件指针位置） %3K'[2F  
private void write_nPos() $qoal   
{ VdL }$CX$  
try{ fB4z
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output = new DataOutputStream(new FileOutputStream(tmpFile)); q}"HxMJ  
output.writeInt(nStartPos.length); vL;=qkTCQ  
for(int i=0;i<nStartPos.length;i++) 3[kl` *`  
{ dr"@2=Z  
// output.writeLong(nPos); MLDAr dvK  
output.writeLong(fileSplitterFetch.nStartPos); ;O .;i,#Z  
output.writeLong(fileSplitterFetch.nEndPos); M?ElD1#Z  
} #D+.z)iZn  
output.close(); Ao9|t;i  
} .MxMBrM  
catch(IOException e){e.printStackTrace ();} p|)j{nc  
catch(Exception e){e.printStackTrace ();} gF~ }  
} 0}Qd  
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//读取保存的下载信息（文件指针位置） 'EU|w,GL}  
private void read_nPos() 8PRB_ny  
{ 5XNFu C9E  
try{ DCCijN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); uKT\\1Jrq  
int nCount = input.readInt(); {~=gKZ:-@  
nStartPos = new long[nCount]; D rouEm  
nEndPos = new long[nCount]; yyjgPbLN=  
for(int i=0;i<nStartPos.length;i++) 61z^(F$@  
{ z8PV&o  
nStartPos = input.readLong(); W%#LHluP  
nEndPos = input.readLong(); Y;sN UX  
} ,fs>+]UY3  
input.close(); \mwxV!!b$  
}  !h*F58  
catch(IOException e){e.printStackTrace ();} wA%,_s/U  
catch(Exception e){e.printStackTrace ();} dM5N1$1,  
} QnH~'
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private void processErrorCode(int nErrorCode) vqwSOh|P9  
{ :\#/T,K"  
System.err.println("Error Code : " + nErrorCode); ~uO9>(?D  
} k/%n7 ;1  
f{R/rb&iB  
/}-LaiS  
//停止文件下载 TUR2|J@n  
public void siteStop() Ktf lbI!  
{ ZOHGGO]1M  
bStop = true; !r_2b! dy  
for(int i=0;i<nStartPos.length;i++) fh}j)*K8  
fileSplitterFetch.splitterStop(); -<n]Sv;V  
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} (fnp\j3w  
} 4kf8Am(  
//负责部分文件的抓取 B#x.4~YX  
**FileSplitterFetch.java -$kAWP8P4  
*/ oyo V1jO  
package NetFox; B3&`/{u  
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import java.io.*; #vvQ1ub  
import java.net.*; !5[5l!{x  
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6 VuMx7W1  
public class FileSplitterFetch extends Thread { 6J%yo[A(w  
i;}mIsNBY  
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String sURL; //File URL AtW<e;!0te  
long nStartPos; //File Snippet Start Position :/'oh]T|  
long nEndPos; //File Snippet End Position R8<P}mv  
int nThreadID; //Thread's ID G^/8lIj  
boolean bDownOver = false; //Downing is over 'nh^'i&0.  
boolean bStop = false; //Stop identical @t?uhT*Z=  
FileAccessI fileAccessI = null; //File Access interface H{j jA
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException VRa>bS  
{ |jE0H!j  
this.sURL = sURL; 8P3"$2q  
this.nStartPos = nStart; 5]yby"Z?}  
this.nEndPos = nEnd; whvvc2  
nThreadID = id; I9;,qd%<T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Y|96K2BR  
} j?y_ H[Z  
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public void run() lcYjwA  
{ Z</.Ss 4  
while(nStartPos < nEndPos && !bStop) x 2Cp{+}  
{ &+zS4)UK  
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try{ wxSJ  
URL url = new URL(sURL); E+e:UBeUV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _Kf8,|+  
httpConnection.setRequestProperty("User-Agent","NetFox"); v)J(@>CZ[  
String sProperty = "bytes="+nStartPos+"-"; \t^h|<`  
httpConnection.setRequestProperty("RANGE",sProperty); +1=]93gP  
Utility.log(sProperty); -{rUE +  
D>efr8Qd@  
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InputStream input = httpConnection.getInputStream(); yRv4,{B}X>  
//logResponseHead(httpConnection); G2BB]] m3  
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vd  
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byte[] b = new byte[1024]; (N :vDq'  
int nRead; c}r"O8M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;o-c.-!F  
{ T1_>qnSz  
nStartPos += fileAccessI.write(b,0,nRead); M=Cl|  
//if(nThreadID == 1) }*9mNE  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \o
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} I$w:
qS&:  
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Utility.log("Thread " + nThreadID + " is over!"); A{Dy3tm=  
bDownOver = true; bx8;`QMX  
//nPos = fileAccessI.write (b,0,nRead); {YigB  
} K@>($BX]  
catch(Exception e){e.printStackTrace ();} HS >B\Ip"  
} H^r;,Q$9  
} JOFQyhY0>m  
^^Te  
@K=C`N_22  
//打印回应的头信息 GZWU=TC2{2  
public void logResponseHead(HttpURLConnection con) ]<Kkq!  
{ "';K$&,[  
for(int i=1;;i++) C 5 xsh  
{ d !=AS  
String header=con.getHeaderFieldKey(i); ?3=y]Vb+  
if(header!=null) I)wc&>Lc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^9fY
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Utility.log(header+" : "+con.getHeaderField(header)); %v)O!HC}  
else h1REL^!c  
break; Dlqvz|X/  
} "cDMFu  
} >&%#`PKT  
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public void splitterStop() '4"c#kCKL  
{ bAS/cuZs  
bStop = true; Jy?; <  
} ?8]g&V  
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} n5>OZ
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!hWS%m@  
/* :Fh#"<A&&  
**FileAccess.java l
#bE_PD;  
*//文件访问(定位，写) :erfs}I  
package NetFox; V 0z`p"  
import java.io.*; r@u8QhD  
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public class FileAccessI implements Serializable{ u
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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 F_-}GN%  
RandomAccessFile oSavedFile; Xb2.t^ ]f  
long nPos; 7.FD16  
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public FileAccessI() throws IOException .OcI.1H[  
{ ex6QHUQ  
this("",0); i62GZeE  
} PvB{@82  
+;/ s0  
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public FileAccessI(String sName,long nPos) throws IOException \c4D|
7\=  
{ 7Fzj&!>ti  
oSavedFile = new RandomAccessFile(sName,"rw"); sT'j36Nc<,  
this.nPos = nPos; ~yiw{:\  
oSavedFile.seek(nPos); _lrvK99  
} crQ_@@X?<  
wA\a ]X.  
N$N7aE$  
public synchronized int write(byte[] b,int nStart,int nLen) %E2V$l0  
{ d.$0X/0  
int n = -1; }'`}| pM$  
try{ 3/V0w|Z
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oSavedFile.write(b,nStart,nLen); |.;*,bb|3  
n = nLen; *I.eCMDa  
} [\-)c[/  
catch(IOException e) `*",_RO;  
{ >u+%H vzc  
e.printStackTrace (); sA2esA@C<o  
} W:>XXUU  
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return n; u0F{
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} MO%+rf0~w  
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} 5Nl?Km~  
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!v. <H]s)  
/* Q zp!)i  
**SiteInfoBean.java RQ;w$I\  
*/ $Y M(NC  
package NetFox; 5,J.$Sax  
bbT1p:RF  
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public class SiteInfoBean { >i"WKd=  
EY^?@D_<  
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private String sSiteURL; //Site's URL gg/2R?O]  
private String sFilePath; //Saved File's Path ;)FmN[  
private String sFileName; //Saved File's Name tyFsnck  
private int nSplitter; //Count of Splited Downloading File 4%#q.qI  
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public SiteInfoBean() XT?wCb41R  
{//nSplitter的缺省值为5 Clb7=@f  
//default value of nSplitter is 5 Nq1YFI>W  
this("","","",5); P9W?sPnC5  
} t;`ULp~&  
T:SqENV  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \k{d'R#~(  
{ YJ|U|[
 
sSiteURL= sURL; p
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sFilePath = sPath; rl,i,1t  
sFileName = sName; _nM 7SK  
this.nSplitter = nSpiltter; Hk'R!X  
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=b, m31  
} 0g9y4z{H  
=]S,p7*7  
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public String getSSiteURL() +j %y#_~  
{ a(kY,<}  
return sSiteURL; v 6s]X*l?  
} Rg^ps  
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R90#T6^  
public void setSSiteURL(String value) V|~o`(]  
{ \OXQ%J2v  
sSiteURL = value; ](FFvqA  
} @,9YF}  
7'#_uAQR  
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public String getSFilePath() E 02Y,C  
{ [^W +^3V  
return sFilePath; N>CNgUyP  
} :| !5d{8S8  
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%=$Knc_!T^  
public void setSFilePath(String value) yy+:x/(N[  
{ &*745,e  
sFilePath = value; o=6 <?v7  
} 6AoKuT;
 
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|*DkriYY  
public String getSFileName() -{q'Tmst  
{ upZtVdd  
return sFileName; FmhAUe  
} V(8,94vm  
2x<!>B  
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public void setSFileName(String value) L6#4A3yh  
{ =k>fW7e  
sFileName = value; m41%?uC/  
} TV#>x!5!d  
TY%=Y=  
!l]_c5  
public int getNSplitter() yZN~
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{ o/Q|R+yXV  
return nSplitter; %'X~9Pvi  
} r*dNta<  
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PT }J.Dwx  
public void setNSplitter(int nCount) _8!x  
{ 0X4)=sJP  
nSplitter = nCount; 3y,2RernK  
} IMBj
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} R1/c@HQw?  
=XK}eQ_d  
|KY-kRN7  
/* uGF{0)0g  
**Utility.java t2YB(6w+xg  
*/ gVe]?Jva`  
package NetFox; q#SEtyJL  
3=^)=yOd  
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public class Utility { *l;S"}b*,_  
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public Utility() ;9~ WB X"  
{ pwkTe  
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} c*]f#yr?  
gcB hEw  
//线程睡眠 %H;}+U]Z  
public static void sleep(int nSecond) 8a&c=9  
{ `6lOqH  
try{ hlZ{bO'f  
Thread.sleep(nSecond); IC(:RtJ  
} H XF
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catch(Exception e) z&B9Yu4M7  
{ ^#Mp@HK  
e.printStackTrace (); N/'  
} .ZV='i()X  
} j S[#R_  
>*opEI+  
//日志 \*'@F+  
public static void log(String sMsg) dJ#go*Gn  
{ wy .96  
System.err.println(sMsg); w%plK6:6  
} Tl'wA^~H  
r>7+&s*yk  
$(+xhn(O  
public static void log(int sMsg) K0>+-p oL  
{ [ZC\8tP`V  
System.err.println(sMsg); 93:oXyFjD  
} 97$Q?a8S@  
} TET=>6  
lM}-'8tt?  
iF":c}$.  
/* /H"fycZ  
**TestMethod.java )Tp"l"(G  
*/ qp/1tC`  
package NetFox; [f! { -T  
bJ2>@|3*  
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public class TestMethod { #ACT&J  
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?|/K(}  
public TestMethod() dQZdL4  
{ ///xx/weblogic60b2_win.exe 9<&M~(dwT4  
try{ JqZt1um  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zi3v,Kq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); RgUQ
:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); t72u%M6  
fileFetch.start(); bmK  
} 1#%H!GKvTU  
catch(Exception e){e.printStackTrace ();} ot[ZFF\  
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2O*At%CzW  
} 6W{Nw<  
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public static void main(String[] args) Bpm COA  
{ s]OZ+^Z  
new TestMethod(); rks"y&&Nc  
} (H&HS
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}
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