http断点续传简单实现（java)

/* :{AN@zC0\  
**SiteFileFetch.java Mfz5:'  
*/ IX>|bA;  
package NetFox; Y.73I83-j  
import java.io.*; 3LTO+>, |"  
import java.net.*; Q\rqG  
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public class SiteFileFetch extends Thread { ,S8Vfb &  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ENmo^O#,u  
long[] nStartPos; //开始位置 e}?t[aK4#  
long[] nEndPos; //结束位置 ~\/ J&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y
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long nFileLength; //文件长度 a=J?[qrx  
boolean bFirst = true; //是否第一次取文件 CVUDN2  
boolean bStop = false; //停止标志 A1@-;/H3  
File tmpFile; //文件下载的临时信息 -Rvxjy)[N  
DataOutputStream output; //输出到文件的输出流 .dfTv/n  
22
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &l.^UQ   
public SiteFileFetch(SiteInfoBean bean) throws IOException @N(jd($E  
{ Dxe|4"%^  
siteInfoBean = bean; /}VQzF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); she`_'?5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r" D|1  
if(tmpFile.exists ()) \xdt|:8  
{ xvkof 'Q)  
bFirst = false; y
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read_nPos(); u7;A`  
} i~.[iZf|  
else F>M$|Sc2  
{ 5[3hw4  
nStartPos = new long[bean.getNSplitter()]; GWW@8GNI  
nEndPos = new long[bean.getNSplitter()]; 4 hj2rK'y  
} VgdkCdWRm_  
]`NbNr]K  
*Z]| Z4Q/`  
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} i-<=nD&?t  
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public void run() 8x{vgx @M  
{ wv7jh~x(4  
//获得文件长度 ~;+vF
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//分割文件 Y1~SGg7(@  
//实例FileSplitterFetch =j{jylC  
//启动FileSplitterFetch线程 H>r-|*n  
//等待子线程返回 Wf?sJ`.%b  
try{ U\[V !1O  
if(bFirst) 4A&e+kz&:R  
{ {$t*Mb0  
nFileLength = getFileSize(); gB"Tc[l1  
if(nFileLength == -1) (HF,p,h_  
{ epL[PL}  
System.err.println("File Length is not known!"); EH3G|3^xz  
} yI%> w4Z  
else if(nFileLength == -2) EzyIsp> _  
{ G225Nz;Y*  
System.err.println("File is not access!"); <8bO1t^*  
} ~ /[Cgh0  
else CvW((<?  
{ +wSm6*j7=  
for(int i=0;i<nStartPos.length;i++) iF0
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{ K8Y/XE
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5 QeGx3'  
} jysV%q 3  
for(int i=0;i<nEndPos.length-1;i++) Dmi;# WY  
{ >SJ$41"E  
nEndPos = nStartPos[i+1]; ]~zJ
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} n96gDH*  
nEndPos[nEndPos.length-1] = nFileLength; Fs|;>Up0  
} YUb,5Y0  
} L,Nr,QC-  
z|<oxF.  
]Yu+M3Fq  
//启动子线程 V[M#
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; acZHb[w  
for(int i=0;i<nStartPos.length;i++) l!y _P  
{ D5>~'N3b  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (0Qq rNs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J9FNjM[qe  
nStartPos,nEndPos,i); 5jQP"^g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Fdw[CYHz  
fileSplitterFetch.start(); FNM"!z  
} _e_%U<\4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eh>E).  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $te,\$&}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 48Lmy<}*  
nEndPos = " + nFileLength); (3h*sd5ly  
// fileSplitterFetch[nPos.length-1].start(); }Yl=lcvw  
E?mp6R]}%  
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//等待子线程结束 `Cf en8  
//int count = 0; Y/66`&,{  
//是否结束while循环 g)A0PvEu  
boolean breakWhile = false; ug,|'<G+  
I 6YT|R  
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while(!bStop) }?J5!X  
{ #6jwCEo=V  
write_nPos(); &] 6T^.  
Utility.sleep(500); --YUiNh
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breakWhile = true; mJ>99:W+  
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j2 ^T:q[  
for(int i=0;i<nStartPos.length;i++) l&Ghs@>Kl  
{ Vk_&W.~  
if(!fileSplitterFetch.bDownOver) t)Q@sKT6  
{ ('-}"3  
breakWhile = false; X9A[  
break; |a$w;s>\  
} Z{4aGp*  
} AdW2o|Uap  
if(breakWhile) rOHW  
break; (y=o]Vy  
FTnQqDuT  
[0ffOTy  
//count++; Ju7C?)x  
//if(count>4) $cK B+}  
// siteStop(); zZc@;S#  
} Qz(T[H5%W  
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System.err.println("文件下载结束！"); DIp:S&q2  
} "ue$DyN  
catch(Exception e){e.printStackTrace ();} #Rx"L&3Ue  
} wLN2`ucC  
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//获得文件长度 >DUE8hp;<  
public long getFileSize() Hq\E06S@  
{ M|#5gKXd  
int nFileLength = -1; Z)i1?#  
try{ ([CnYv  
URL url = new URL(siteInfoBean.getSSiteURL()); x<j"DS}S)D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?U/Wio$@  
httpConnection.setRequestProperty("User-Agent","NetFox"); `6N-MsP  
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int responseCode=httpConnection.getResponseCode(); {dA ~#fW<  
if(responseCode>=400) BH0#Q5  
{ ho]!G498  
processErrorCode(responseCode); MupW=3.38  
return -2; //-2 represent access is error C$td{tM  
} 7;}3{z  
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String sHeader; hRa(<ZK  
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for(int i=1;;i++) Mev-M2A  
{ zt[4_;2Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +:]Aqyc\  
//Utility.log(in.readLine()); EPe]-C`  
sHeader=httpConnection.getHeaderFieldKey(i); '<&EPUO  
if(sHeader!=null) X'#$e{  
{ B.mbKntK)R  
if(sHeader.equals("Content-Length")) aDl, K;GL  
{ g{W6a2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); blfE9Oy  
break; {pe7]P?  
} HCx%_9xlm  
}
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else 8gbm"!  
break; B3>Uba*-)}  
} \l]pe|0EW  
} 'y6!%k*  
catch(IOException e){e.printStackTrace ();} {y&\?'L'  
catch(Exception e){e.printStackTrace ();} Y%)h)El  
@nx}6?p\,  
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Utility.log(nFileLength); 9]L!.  
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return nFileLength; xZP
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} bwSRJFqb  
5hJYy`h~  
0Z A#T:4  
//保存下载信息（文件指针位置） '9 *|N=  
private void write_nPos() &:DCtjK  
{ y*}vG}e%  
try{ DN"S,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (K*/Vp  
output.writeInt(nStartPos.length); (~G5t(+  
for(int i=0;i<nStartPos.length;i++) Gf H*,1x  
{ ii_|)udz  
// output.writeLong(nPos); :m*!?QGdL  
output.writeLong(fileSplitterFetch.nStartPos); G9i&#)nWr  
output.writeLong(fileSplitterFetch.nEndPos); Db#W/8 a8k  
} fVH*dX'Jz  
output.close(); [ZKtbPHb  
} GX7 eRqz>  
catch(IOException e){e.printStackTrace ();} 2q-:p8  
catch(Exception e){e.printStackTrace ();} bB;~,W&E1  
} (ET ;LH3  
@.Z
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+~w?Xw,  
//读取保存的下载信息（文件指针位置） <V$Y6(uMs  
private void read_nPos() :dY.D|j*  
{ `;5VH]V  
try{ "%oH@ =  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _K0izKTA.  
int nCount = input.readInt(); HPtTv}l  
nStartPos = new long[nCount]; "Ju/[#VCJ  
nEndPos = new long[nCount]; !F+|Y"c  
for(int i=0;i<nStartPos.length;i++) U|Bsa(?nx  
{ )IFl 0<d  
nStartPos = input.readLong(); ;wJ7oj<  
nEndPos = input.readLong(); smfG,TI  
} #~H%[sa  
input.close(); Uz6{>OCvk|  
} c~gNH%1XN  
catch(IOException e){e.printStackTrace ();} 'v\1:zi  
catch(Exception e){e.printStackTrace ();} &/>;LgN  
} 0" U5oP[  
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private void processErrorCode(int nErrorCode) (s}Rj)V[^  
{ DKy>]Hca  
System.err.println("Error Code : " + nErrorCode); ~\IF9!  
} $ \Q<K@{  
/h}PEu3y  
I.^
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//停止文件下载 k4qLB1&,  
public void siteStop() z5XYpi_;[  
{ _M8G3QOx  
bStop = true; Z/2,al\  
for(int i=0;i<nStartPos.length;i++) 3]O`[P,*%  
fileSplitterFetch.splitterStop(); IL~]m?'V(  
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n-b>m7O(  
} k{gl^  
} 7?6xPKQ)H  
//负责部分文件的抓取 e[x?6He,$  
**FileSplitterFetch.java A Gv!c($  
*/ 0+T*$=?  
package NetFox; ZYE' C  
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import java.io.*; DMF?5GX  
import java.net.*; J[
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public class FileSplitterFetch extends Thread { |-~b$nUe  
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String sURL; //File URL oM6j>&$b  
long nStartPos; //File Snippet Start Position ^cYStMjpy  
long nEndPos; //File Snippet End Position h&)fu{   
int nThreadID; //Thread's ID 3jvx2  
boolean bDownOver = false; //Downing is over r5t;'eCea  
boolean bStop = false; //Stop identical _*O7l  
FileAccessI fileAccessI = null; //File Access interface 3p:=xL  
Z5((1J9  
jCU=+b=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \Dn&"YG7  
{ B4`2.yRis  
this.sURL = sURL; qBT_! )h   
this.nStartPos = nStart; &MCy.(jN  
this.nEndPos = nEnd; L +L9Y}  
nThreadID = id; ;tJWOm  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 T"n{WmVQ  
} -glugVq  
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public void run() V?OuIg%=:  
{ :1:3Svb<Y  
while(nStartPos < nEndPos && !bStop) 8]S,u:E:N  
{ ~mtTsZc  
~j=xiP  
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try{ AT"!{Y "H  
URL url = new URL(sURL); Vwjk[ DOL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ov8 ByJc  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?Phk~ jE  
String sProperty = "bytes="+nStartPos+"-"; kW#S]fsfU  
httpConnection.setRequestProperty("RANGE",sProperty); q[-|ZA bbr  
Utility.log(sProperty); n'THe|:I  
9/#0
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InputStream input = httpConnection.getInputStream(); 0s1'pA'  
//logResponseHead(httpConnection); G3G/xC"  
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byte[] b = new byte[1024]; UcgG  
int nRead; rVY?6OMkd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) t{!/#eQC  
{ 1j11|~  
nStartPos += fileAccessI.write(b,0,nRead); VM7 !0  
//if(nThreadID == 1) $H'8 #:[d_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^7.XGWQ)-  
} 1n_;kaY  
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Utility.log("Thread " + nThreadID + " is over!"); l';pP^.q  
bDownOver = true; <j;]!qFR  
//nPos = fileAccessI.write (b,0,nRead); ',GV6kt_k  
} o7.e'1@  
catch(Exception e){e.printStackTrace ();} T.kyV|  
} kBo;h.[l  
} -LTKpN`[@  
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//打印回应的头信息 ;+sl7qlA4  
public void logResponseHead(HttpURLConnection con) xOythvO  
{ t-WjL@$F/  
for(int i=1;;i++) 6Opa{]  
{ r088aUO P  
String header=con.getHeaderFieldKey(i); ^5>s7SGB"  
if(header!=null) F+m[&MKL  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); b(l0js  
Utility.log(header+" : "+con.getHeaderField(header)); C6|(ktt  
else uVGa(4u}  
break; [& ^RP,N~  
} X1oGp+&  
} Oa! m  
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public void splitterStop() WfZF~$li`  
{
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bStop = true; :$?Q D  
} wd/G|kNO  
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} }k7_'p&yk  
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f8=]oa]  
/* 6W&_2a7*  
**FileAccess.java ?1peF47Z
 
*//文件访问(定位，写) zPR8f-Uvw  
package NetFox; %m eLW&  
import java.io.*; ?DPHo)w  
Z.'syGuV  
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public class FileAccessI implements Serializable{ Pz%~ST  
a[sKE?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 RP! X8~8  
RandomAccessFile oSavedFile; )u*^@Wo  
long nPos; GKZN}bOm\  
?iv=53<c#  
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public FileAccessI() throws IOException E=AVrv5T  
{ jZd}OC<  
this("",0); n*<v]1  
} .po>qb6  
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)6-9)pH@)  
public FileAccessI(String sName,long nPos) throws IOException [ ny6W9  
{ ZSB?Y1wG  
oSavedFile = new RandomAccessFile(sName,"rw"); l+zb~  
this.nPos = nPos; 71"+<C .  
oSavedFile.seek(nPos); ]a?bzOr,  
} $shp(T,q  
X:EEPGE  
7C7>y/uS  
public synchronized int write(byte[] b,int nStart,int nLen) 7O)" `  
{ FOH@OY  
int n = -1; 6ZOy&fd,Ty  
try{ 1$pb (OK  
oSavedFile.write(b,nStart,nLen); bcH_V|5
}  
n = nLen; <{Q'&T  
} s_[VHPN  
catch(IOException e) 0 )}$^TV  
{ 7 ^$;  
e.printStackTrace (); D#Kuo$  
} QR0(,e$Dl  
h/)_) r.x  
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return n; hH>``gK  
} G$bJ+  
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} 3@<zg1.9-  
0N;%2=2_E  
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/* W0I4Vvh_"  
**SiteInfoBean.java 8)j@aiF`  
*/ eE(b4RCM  
package NetFox; 7TX2&kMoc  
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public class SiteInfoBean { MYdO jcN  
`<frgXu64  
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private String sSiteURL; //Site's URL F<|t\KOW  
private String sFilePath; //Saved File's Path B^v8,;jZT  
private String sFileName; //Saved File's Name 8sOQ
9  
private int nSplitter; //Count of Splited Downloading File O;uG?.\  
,$lemH1d  
i=S~(gp  
public SiteInfoBean() "ju'UOcS/  
{//nSplitter的缺省值为5 iE].&>w  
//default value of nSplitter is 5 F@YKFk+a  
this("","","",5); j;0vAf  
} sG7u}r  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 78 f$6J q  
{ kz}R[7  
sSiteURL= sURL; U7h(`b  
sFilePath = sPath; B1!kn}KlL{  
sFileName = sName; x;s0j"`Jb  
this.nSplitter = nSpiltter; 0#_'o ,  
i3$$,W!  
fyknP)21I  
} Lgk  
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public String getSSiteURL() 3uWkc3  
{ 4?\:{1X=  
return sSiteURL; 49H+(*@v@  
} !69&Ld  
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<AH1i@4  
public void setSSiteURL(String value) +Vb8f["+-  
{ ^D%Za'  
sSiteURL = value; zP\7S}p7%  
} R%Y`=
pK>}  
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public String getSFilePath()
=FP0\cQ.  
{ 4GdX/6C.  
return sFilePath; 58Xzup_"  
} e'%v1-&sP  
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rwLAW"0Qz  
public void setSFilePath(String value) (V`Md\NL`  
{ i%m"@7.kk  
sFilePath = value; W,5Hx1z R  
} W !w,f;  
XRx+Dddt;  
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public String getSFileName() @gC=$A#  
{ Rhc-q
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return sFileName; FY{e2~gi  
} CC=d I  
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public void setSFileName(String value) *g}Yw  
{ YHk
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sFileName = value; E>'a,!QPv  
} c/N@zum,{  
"5R~(+~<@  
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public int getNSplitter() EP'h@zdz  
{ \>LnLH(  
return nSplitter; L!0OC''C  
} ULrr=5&8  
!* Ti}oIo&  
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public void setNSplitter(int nCount) 9vUO
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{ !U9|x\BqJ2  
nSplitter = nCount; h,aAw#NE*  
} ryF7  
} f"7O "6  
VVH.2&`I  
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/* voP7"Dl[  
**Utility.java wN1niR'  
*/ |8>3`w!  
package NetFox; [[PEa-992  
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!tfb*@{;'  
public class Utility { IW 21T  
|(5W86C,ju  
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public Utility() FuI73  
{ *f&EoUk}F  
{!6/x9>  
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} t@u7RL*n:<  
w
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//线程睡眠 pyLRgD0 g  
public static void sleep(int nSecond) #e' }.4cr  
{ -F'b8:m  
try{ 8Ac)'2t;U  
Thread.sleep(nSecond); Bm&kkx.9P  
} ~|<WHHN
(  
catch(Exception e) \
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{ bM8If"  
e.printStackTrace (); mPI8_5V8]  
} 0/S_e)U  
} hxCvk/7sT  
'smWLz}  
//日志 8} =JKR^cK  
public static void log(String sMsg) nF6q7  
{ nKW*Y}VO  
System.err.println(sMsg); x77l~=P+!  
} !vG'J\*xc  
W
VVJ  
f|O{#AC  
public static void log(int sMsg) o-}R?>  
{ :ba5iMa  
System.err.println(sMsg); 2M#r]  
} 3nZo{p:E  
} ,%\o4Rc'o  
\ [a%('}  
sR/b$j>i3  
/* bh^LIU  
**TestMethod.java ,
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*/ =-_B:d;  
package NetFox; %f($*l.  
jqPkc28  
=bEda]  
public class TestMethod { I\Y
V des#  
PO6&bIr  
m0v:\?S:  
public TestMethod() |V<h=D5W  
{ ///xx/weblogic60b2_win.exe 035rPT7-2-  
try{ v|U(+O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ZDbc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M5xCC!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2W4qBaG$=  
fileFetch.start(); JV;OGh>  
} ]T%rjsN  
catch(Exception e){e.printStackTrace ();} 4:U?u  
BJ% eZ.  
! u:Weoz  
} qUly\b 47  
e^.Fa59  
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public static void main(String[] args) )/
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{ Mn)@{
^  
new TestMethod(); mdRU^n  
} =$]uoA  
} r$2P;Cxj  
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