http断点续传简单实现（java)

/* "\vEi &C  
**SiteFileFetch.java un6grvxr  
*/ pYI`5B4  
package NetFox; Od>Ta_  
import java.io.*; SvAz9>N4  
import java.net.*; :'f#0ox  
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public class SiteFileFetch extends Thread { hp%|n:.G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean @mNf(&  
long[] nStartPos; //开始位置 /.aZXC$]  
long[] nEndPos; //结束位置 @PZ&/F^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a_L&*%;  
long nFileLength; //文件长度 f&js,NU"  
boolean bFirst = true; //是否第一次取文件 )2g\GRg6  
boolean bStop = false; //停止标志 9|D!&=8   
File tmpFile; //文件下载的临时信息 n9050&_S  
DataOutputStream output; //输出到文件的输出流 ?<#6=  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） dum! AO  
public SiteFileFetch(SiteInfoBean bean) throws IOException YCj"^RC^  
{ ,6}HAC $  
siteInfoBean = bean; >+7+ gSD#:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d@b"tb}R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \Bw9%P~ G  
if(tmpFile.exists ()) %njX'7^u  
{ uPsn~>(4  
bFirst = false; a/NmM
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read_nPos(); DCPK1ql  
} S3MMyS8  
else G{knO?BK  
{ 3:PBVt=  
nStartPos = new long[bean.getNSplitter()]; iJZqAfG{m?  
nEndPos = new long[bean.getNSplitter()]; ;jfjRcU  
} }wC pr.@  
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} g*N~r['dZ  
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public void run() m_W\jz??k  
{ ;? '`XB!  
//获得文件长度 %q;3bfq@N  
//分割文件 R."<he ;  
//实例FileSplitterFetch {[jcT>.3j  
//启动FileSplitterFetch线程 5H6m{ng  
//等待子线程返回 =IkQ;L&  
try{ \'q-Xr'}M  
if(bFirst) up=4B  
{ d8C?m*3J  
nFileLength = getFileSize(); !?DPI)  
if(nFileLength == -1) f h)Cz)  
{ I')URk[  
System.err.println("File Length is not known!"); 2Y(Phw2%  
} ~x)Awdlu  
else if(nFileLength == -2) QjWv?tm  
{ 7Wmk"gp  
System.err.println("File is not access!"); z[M LMf[c  
} .6z#o{n  
else U-QK   
{ O/e5LA  
for(int i=0;i<nStartPos.length;i++) L Bb&av  
{ Cl7IP<.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1tDd4r?Y  
} m>x.4aO1  
for(int i=0;i<nEndPos.length-1;i++) \;&j;"c,W  
{ :2^%^3+V  
nEndPos = nStartPos[i+1]; KqP!={>"  
} SuB;Nb7r`  
nEndPos[nEndPos.length-1] = nFileLength; c_~)#F%P  
} |qH-^b.F  
} Sqed*  
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//启动子线程 [<}:b>a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; x>A(016:C  
for(int i=0;i<nStartPos.length;i++) /1zi(z   
{ \L}Soe'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f>s3Q\+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2oXsPrtZ  
nStartPos,nEndPos,i); *TfXMN?w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); awB1ryrOF  
fileSplitterFetch.start(); 8
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} DxdiXf[j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j5Vyo>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :7KcD\fCj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \zR@FOl`q  
nEndPos = " + nFileLength); q{ItTvL  
// fileSplitterFetch[nPos.length-1].start(); S;kI\;  
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//等待子线程结束 M/x49qO#  
//int count = 0; ( MWh|kp  
//是否结束while循环 eGHxiC  
boolean breakWhile = false; ^ b{0|:  
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while(!bStop) -M2c8P:.b  
{ <.HX_z3l  
write_nPos(); m=jxTZK  
Utility.sleep(500); z4!TK ps  
breakWhile = true; ?x7zYE,6  
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for(int i=0;i<nStartPos.length;i++) wS-D"\4/  
{ )s5Q4m!  
if(!fileSplitterFetch.bDownOver) mY*JNx  
{
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breakWhile = false; %D< =6suW  
break; $bIVD  
} }xcA`w3u2?  
} yw `w6Z3K  
if(breakWhile) X`/8fag  
break; [G>8N5@*  
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~OD}`  
//count++; 5tdFd"oo  
//if(count>4) 3jZPv;9OC  
// siteStop(); Cp`)*P2  
} &<2~7?$!  
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System.err.println("文件下载结束！"); 87l(a,#J  
} 62TWqQ!9d  
catch(Exception e){e.printStackTrace ();} kG@~;*;l  
} Q'/v-bd?o  
/FJ )gQYA  
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//获得文件长度 {&nL'R  
public long getFileSize() uDvZ]Q|.  
{ h)fJ2]JW8W  
int nFileLength = -1; fQ33J>  
try{ `n7*6l<k~4  
URL url = new URL(siteInfoBean.getSSiteURL()); Z`y%#B6x.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y> ElE-  
httpConnection.setRequestProperty("User-Agent","NetFox"); !LB#K?I  
;)].Dj9  
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int responseCode=httpConnection.getResponseCode(); ]awu7}C9Z  
if(responseCode>=400) zO)A_s.6K  
{ n`gW&5,,z  
processErrorCode(responseCode); )F*;7]f  
return -2; //-2 represent access is error ~3bH2,{L[  
} V<:scLm#OF  
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String sHeader; t1"-3afe  
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for(int i=1;;i++) NrA?^F  
{ zV {_dO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'qel3Fs"  
//Utility.log(in.readLine()); t M?3oO  
sHeader=httpConnection.getHeaderFieldKey(i); :j f
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if(sHeader!=null) _]zm02|  
{ ;%wQ
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if(sHeader.equals("Content-Length")) *%'nlAX6%  
{ KYBoGCS>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F
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break; h[HFZv~{  
} ?=$=c8xw  
} (jhDO7  
else j0P+<@y  
break; zv/owK  
} Y,0D+sO4  
} K@d,8[  
catch(IOException e){e.printStackTrace ();} %Y!31oC#  
catch(Exception e){e.printStackTrace ();} DvL/xlN  
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Utility.log(nFileLength); /WqiGkHV*  
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return nFileLength; {Aq2}sRl{  
} ))Q3;mI"  
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//保存下载信息（文件指针位置） ,Hq*zc
c  
private void write_nPos() cvSr><(  
{ MYI*0o
;  
try{ sUl/9VKl  
output = new DataOutputStream(new FileOutputStream(tmpFile)); SA3!a.*c  
output.writeInt(nStartPos.length); L{)*evBL  
for(int i=0;i<nStartPos.length;i++) j\SvfZ0"  
{ xn1=@0 a  
// output.writeLong(nPos); _}G1/`09#  
output.writeLong(fileSplitterFetch.nStartPos); A\xvzs.d  
output.writeLong(fileSplitterFetch.nEndPos); [OTZ"XQLI  
} $/Rr|<  
output.close(); d4(!9O.\  
} ZV,1IaO  
catch(IOException e){e.printStackTrace ();} $K-od3h4=  
catch(Exception e){e.printStackTrace ();} Fk
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} `)Z+]5:  
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//读取保存的下载信息（文件指针位置） #}y(D{zc  
private void read_nPos() P/9iB/  
{ hlIh(\JZ4s  
try{ h 7x_VO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )wFr%wNe  
int nCount = input.readInt(); :>G3N+A)  
nStartPos = new long[nCount]; 6|{$]<'  
nEndPos = new long[nCount]; {Kdr-aC  
for(int i=0;i<nStartPos.length;i++) vBRW5@  
{ s"jNS1B  
nStartPos = input.readLong(); T][r'jWQ  
nEndPos = input.readLong(); cx_.+R  
} aNcuT,=(?8  
input.close(); estDW1i)  
} Qx{[#[Da  
catch(IOException e){e.printStackTrace ();} (=de#wh2]  
catch(Exception e){e.printStackTrace ();} 6<%W8m\  
} e 9p+  
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private void processErrorCode(int nErrorCode) 3B+ F'k&#  
{ Tw)"#Y!T  
System.err.println("Error Code : " + nErrorCode); /d/Quro  
} #"3az8u  
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-( d,AX  
//停止文件下载 "M`ehgCBr  
public void siteStop() 0SJ7Q
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{ 
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bStop = true; ;Xzay|  
for(int i=0;i<nStartPos.length;i++) oJ<Wh @  
fileSplitterFetch.splitterStop(); fD>0  
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} ,pc\ )HR  
} c2$&pZ
M  
//负责部分文件的抓取 vWM'}(  
**FileSplitterFetch.java q1d'L*  
*/ q^.\8zFf  
package NetFox; GiF})e}  
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import java.io.*; Dq~PxcnI  
import java.net.*; HDTdOG)  
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public class FileSplitterFetch extends Thread { A\6Q
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String sURL; //File URL Q<e`0cu|p  
long nStartPos; //File Snippet Start Position /
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long nEndPos; //File Snippet End Position |>Xw"]b;  
int nThreadID; //Thread's ID TYs#v/)
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boolean bDownOver = false; //Downing is over .x^`y2'U  
boolean bStop = false; //Stop identical %5zztReI  
FileAccessI fileAccessI = null; //File Access interface 9gz"r  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zF F=v7[j  
{ limzDQ^  
this.sURL = sURL; 1f.xZgO/2  
this.nStartPos = nStart; o4Bl!7U  
this.nEndPos = nEnd; Vu6pl  
nThreadID = id; ,Cj8{s&;
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l5jW`cl1  
} v7l4g&  
}PR^Dj.  
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public void run() /&+6nOP  
{ qM$~5uu  
while(nStartPos < nEndPos && !bStop) Nr#Y]9nA  
{ `tCOe  
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try{ <?TJ-  
URL url = new URL(sURL); cZ" Ut  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 's]+.3">L1  
httpConnection.setRequestProperty("User-Agent","NetFox"); B) 81mcy  
String sProperty = "bytes="+nStartPos+"-"; \I\'c.$I.Y  
httpConnection.setRequestProperty("RANGE",sProperty); @QAyXwp  
Utility.log(sProperty); 6$'6x2,  
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InputStream input = httpConnection.getInputStream(); IXSCYqoK  
//logResponseHead(httpConnection); GMw|@?:{  
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byte[] b = new byte[1024]; ]c8$%  
int nRead; 9iQcK&D 2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) RfT#kh/5  
{ h&!k!Su3#  
nStartPos += fileAccessI.write(b,0,nRead); "~h.u  
//if(nThreadID == 1) aBM'
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #"M 'Cs  
} C/P,W>8  
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Utility.log("Thread " + nThreadID + " is over!"); 7eh|5e$@  
bDownOver = true; mf26A
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//nPos = fileAccessI.write (b,0,nRead); y>S.B/d  
} F:/R'0  
catch(Exception e){e.printStackTrace ();} 5JbPB!5;  
} 'DQp  
} TsPO+x$l  
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//打印回应的头信息 Po[u6K2&  
public void logResponseHead(HttpURLConnection con) tUmI#.v  
{ b8J\Lm|J  
for(int i=1;;i++) `>fN?He  
{ &DX9m4,y  
String header=con.getHeaderFieldKey(i); #lyvb.;  
if(header!=null) NgKbf vt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %J`;  
Utility.log(header+" : "+con.getHeaderField(header)); xDBEs*  
else F<?e79},`  
break; j$*]'s&_hZ  
} -Uz xs5Zl  
} 1K'0ajl1A  
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public void splitterStop() }6]V*
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{ ]xfAdBi  
bStop = true; s,^?|Eo;0  
} O0xL;@rBe  

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} jlER_I]  
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/* >taS<.G  
**FileAccess.java f8! PeQ?  
*//文件访问(定位，写) l;L&ijTQD  
package NetFox; oll~|J^sg  
import java.io.*; )_T
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public class FileAccessI implements Serializable{ T\:3(+uK  
=&,zWNz)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =~Jv*c  
RandomAccessFile oSavedFile; zQ {g~x  
long nPos; jh]wHG  
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public FileAccessI() throws IOException v,RLN`CID  
{ 2 c'=^0:  
this("",0); @yaBtZUp3  
} +[r%y,
k  
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public FileAccessI(String sName,long nPos) throws IOException %H-[u}s  
{ bF'~&<c  
oSavedFile = new RandomAccessFile(sName,"rw"); UhY )rezh  
this.nPos = nPos; 'oTcx Jx  
oSavedFile.seek(nPos); m7kDxs(KO  
} P58U8MEG  
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public synchronized int write(byte[] b,int nStart,int nLen) Xr M[8a  
{ KLqu[{y.'  
int n = -1; ;sNyN#  
try{ ue/6DwUv  
oSavedFile.write(b,nStart,nLen); ;FZ\PxN  
n = nLen; ;0xCrE{l"  
} SBjtg@:G0n  
catch(IOException e) HtEjM|zj  
{ 8Mg4y1)RU  
e.printStackTrace (); /Fh"Gl^  
} g$dL5N7  
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return n; $2>tfKhtA  
} 2>fG}qYy$  
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} ynM{hN.+H  
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/* (L|SE4  
**SiteInfoBean.java [X^JV/R  
*/ v.6"<nT2  
package NetFox; =]xNpX)  
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public class SiteInfoBean { 9aZ3W<N`M  
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private String sSiteURL; //Site's URL wc bs-arH  
private String sFilePath; //Saved File's Path /GM-#q a  
private String sFileName; //Saved File's Name Z mi<Z  
private int nSplitter; //Count of Splited Downloading File N>ct`a)BD/  
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public SiteInfoBean() ]N=C%#ki!  
{//nSplitter的缺省值为5 #4
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//default value of nSplitter is 5  TWx<)  
this("","","",5); YXIDqTA+  
} ^ ?tAt3dMI  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2z0HB+Y}x  
{ (m04Z2#  
sSiteURL= sURL; mZ/B:)_  
sFilePath = sPath; 1LPfn(  
sFileName = sName; c_ygwO3.Q  
this.nSplitter = nSpiltter; }lpcbm  
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4#2iL+   
} ~BS*x+M  
~iwEhF  
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public String getSSiteURL() mnmwO(.  
{ oN `tZ;a  
return sSiteURL; #mkr]K8A4  
} m qw!C  
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[7I|8
  
public void setSSiteURL(String value) ejr"(m(Xe  
{ cWRB=`=qz  
sSiteURL = value; !+hX$_RT  
} VpVw:Rh>  
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public String getSFilePath() B.P64"w  
{ "BFW&<1  
return sFilePath; '|XP}V0I  
} X2@o"xU
  
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public void setSFilePath(String value) :>3&"T.  
{ U1q$B32  
sFilePath = value; +:'Po.{"  
} nr-
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b$$XriD]  
public String getSFileName() wd#AA#J;*  
{
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return sFileName; +'n1?^U
  
} /pk;E$qv  
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public void setSFileName(String value) >8JvnBFx=  
{ OT *W]f  
sFileName = value; .ERO*Tj  
} 2~`dV_  
,o}[q92@w  
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public int getNSplitter() GUp51*#XR  
{ "mH^Owai  
return nSplitter; ^@19cU?q  
} I9Sh~vTm=u  
h{JVq72R
 
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public void setNSplitter(int nCount) kW:!$MX!  
{ C,<TAm  
nSplitter = nCount; _:K}DU'6  
} jU#%@d6!#  
} nb|MHtPX  
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/* HkV/+ {;S~  
**Utility.java ~%}g"|o  
*/ d:wAI|  
package NetFox; 2 sOc]L:9  
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public class Utility { -qEr-[z  
W ,U'hk%  
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public Utility() y(S0 2v>l  
{ Z0:BXtW  
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+]e4c;`ko}  
} 8)tyn'~i  
F
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//线程睡眠 b;O+
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public static void sleep(int nSecond) 8&;dR  
{ }dR*bG  
try{ jFc{$#g-
 
Thread.sleep(nSecond); kj#yG"3+  
} ~k%\ LZ3s  
catch(Exception e) )~n}ieS  
{ ' FK"-)s  
e.printStackTrace (); Wm,,OioK  
} .=FJ5?:4i%  
} #Nd+X@j  
2X]\:<[4  
//日志 B>mQ\Q  
public static void log(String sMsg) !INr  
{ pqr"x2=.  
System.err.println(sMsg); (BGipX4  
} w}i.$Qt  
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public static void log(int sMsg) o MAK[$k;  
{ =ht@7z8QM  
System.err.println(sMsg); EAkP[au.  
} i*tj@5MY-  
} ')aYkO{%sb  
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DXGO-]!!0  
/* y*D 8XI$  
**TestMethod.java PA/6l"-`3  
*/ b1OB'P8  
package NetFox; DNy)\+[  
# 9t/j`{  
@e7+d@O<  
public class TestMethod { 3IkG*enI  
vKt_z@{{L  
;4bu=<%  
public TestMethod() 8dH|s#.4um  
{ ///xx/weblogic60b2_win.exe N#:"X;  
try{ gc=e)j@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6xe |L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ep!.kA=\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (`p(c;"*C!  
fileFetch.start(); /$=^0v+  
} upr
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catch(Exception e){e.printStackTrace ();} U&XoT-p$L  
]VME`]t`  
1}pR')YL[  
} 'FhnSNT(4=  
=jN]ckn  
'zb7:[[7%  
public static void main(String[] args) a?kQ2<@g  
{ uz#9w\="  
new TestMethod(); cPbz7  
} 5ZVTI,4K  
} k.ZfjX"  
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