http断点续传简单实现（java)

/* :EmMia-)J  
**SiteFileFetch.java !IrKou)/_  
*/ ;Ef)7GE@\[  
package NetFox; {pi67"mYp  
import java.io.*; 8Gzs  
import java.net.*; H#d! `  
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public class SiteFileFetch extends Thread { }j5@\c48  
#)c;i<Q3S  

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SiteInfoBean siteInfoBean = null; //文件信息Bean d+wNGN  
long[] nStartPos; //开始位置 %#;(]7Zq  
long[] nEndPos; //结束位置 3 %{'Uh,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (]# JpQ  
long nFileLength; //文件长度 _J$p<  
boolean bFirst = true; //是否第一次取文件 "}Sid+)<  
boolean bStop = false; //停止标志 Zm'::+tl  
File tmpFile; //文件下载的临时信息 MLDg).5  
DataOutputStream output; //输出到文件的输出流 /$N#_Xblr  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'c\TMb.  
public SiteFileFetch(SiteInfoBean bean) throws IOException p9bxhnn|  
{ "7u"d4h-:(  
siteInfoBean = bean; %EhU!K#[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;`Ch2b1+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x>/@Z6Wxz  
if(tmpFile.exists ()) DT~y^h  
{ pHbguoH,  
bFirst = false; t~=@r9`S  
read_nPos(); p[+me o  
} }u$aPS<$!  
else fP4IOlHkE  
{ $@!&ML  
nStartPos = new long[bean.getNSplitter()]; C4K&flk]  
nEndPos = new long[bean.getNSplitter()]; %>}7$Y%  
} >]N0w  
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} ;DWp>jgy  
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public void run() n`2"(7Wj  
{ 5/VB'N#7s  
//获得文件长度 nylIP */  
//分割文件 A>,fG9pR  
//实例FileSplitterFetch Xg)FIaw]eT  
//启动FileSplitterFetch线程 {Ao^3vB  
//等待子线程返回 Ljs(<Gm)-  
try{ 'F<e)D?  
if(bFirst) hLA=7  
{ Sgk{NM7|k  
nFileLength = getFileSize(); 8o!^ZOmU<  
if(nFileLength == -1) .VV!$; FB  
{ U.9nHo{  
System.err.println("File Length is not known!"); AxQ/  
} {oC69n
:  
else if(nFileLength == -2) ~}l,H:jk@  
{ 3W WxpTU  
System.err.println("File is not access!"); mq} #{  
} s8O+&^(U  
else #FM 'S|  
{ s'w0pZqj  
for(int i=0;i<nStartPos.length;i++) oW9rl]+  
{ "qp_*Y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); M|u5Vs1  
} :Bc;.%  
for(int i=0;i<nEndPos.length-1;i++) d'J?QH!N0  
{ :G)x+0u  
nEndPos = nStartPos[i+1]; |pg5m*h  
} +u.L6GcB  
nEndPos[nEndPos.length-1] = nFileLength; ~hX'FV  
} 2}#PDhn  
} sbIhg/:ok  
eT?LMBn\  
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//启动子线程 5jk4k c  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {1ceF  
for(int i=0;i<nStartPos.length;i++) 40ZB;j$l  
{ c *noH[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), arrcHf4O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), o%7yhCY  
nStartPos,nEndPos,i); ?2Dz1#%D  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Kj5f:{Ur  
fileSplitterFetch.start(); *a@UV%u  
} )9,"~P2[R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hn.UJ4V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yh!vl&8M  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -|mRJVl8  
nEndPos = " + nFileLength); [G)Sq;  
// fileSplitterFetch[nPos.length-1].start(); #d(r^U#I  
;I'["k%  
/y@i
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//等待子线程结束 ,B!Qv3bn  
//int count = 0; tam/FzVw  
//是否结束while循环 7Kjq1zl;  
boolean breakWhile = false; ^5F/=TtE G  
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while(!bStop) }(6k7{,Gw,  
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write_nPos(); Rl8-a8j$f.  
Utility.sleep(500); ~VKXL,.  
breakWhile = true; $T0[  
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for(int i=0;i<nStartPos.length;i++) qa6up|xUnn  
{ 
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if(!fileSplitterFetch.bDownOver) c^%k1pae(  
{ +UtK2<^:o  
breakWhile = false; egvWPht'_  
break; 9IV WbJ  
} ?i"FdpW  
} pj6Cvq4bD  
if(breakWhile) %cL:*D4oz  
break; TMBdneS-s  
I&c#U+-A'  
on$a]zx'@  
//count++; K<(RVh  
//if(count>4) f ;JSP  
// siteStop(); !NtY4O/  
} wr(?L7 $+  
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System.err.println("文件下载结束！"); b :
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} AH
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catch(Exception e){e.printStackTrace ();} 98"NUT  
} I5,Fh>  
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//获得文件长度 dmne+ufB  
public long getFileSize() 2NM}u\%c/  
{ ;a"Ukh  
int nFileLength = -1; YQOGxSi  
try{ h?sh#j6  
URL url = new URL(siteInfoBean.getSSiteURL()); c-F&4V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >8so'7(  
httpConnection.setRequestProperty("User-Agent","NetFox"); YuZnuI@m9  
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int responseCode=httpConnection.getResponseCode(); (0r6_8e6xv  
if(responseCode>=400) e[n>U@  
{ !*;)]j  
processErrorCode(responseCode); AF !_!qc;  
return -2; //-2 represent access is error sXTO`W/  
} H{8\<E:V+}  
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String sHeader; ;_!;D#:  
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for(int i=1;;i++) N*#SY$!y  
{ G(>a LF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6*E7}  
//Utility.log(in.readLine()); s$;v )w$  
sHeader=httpConnection.getHeaderFieldKey(i); UZ$p wjC  
if(sHeader!=null) -9mh|&z`  
{ BshS@"8r  
if(sHeader.equals("Content-Length")) XcXd7e  
{ 8Vx'sJ>r4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R=l/EK  
break; .gB*Y!c7  
} c72/e7gV  
} c!c!;(  
else 3HD=)
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break; s$Mj4_p3l  
} y=CemJ[
~  
} GZ"O%:d  
catch(IOException e){e.printStackTrace ();} iiu\_ a=0b  
catch(Exception e){e.printStackTrace ();} No?pv"  
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Utility.log(nFileLength); a)]N#gx  
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:\ S3[(FV  
return nFileLength; iH2|w  
} {pqm&PB04  
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//保存下载信息（文件指针位置） <H.Ml>q:r  
private void write_nPos() Z1&8U=pax  
{ \6o ~ i  
try{ d%<Uh(+:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); W\"cp[b  
output.writeInt(nStartPos.length); <B)lV'!Bd  
for(int i=0;i<nStartPos.length;i++) QS[%`-dR2  
{ *N't ;  
// output.writeLong(nPos); 5%9
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output.writeLong(fileSplitterFetch.nStartPos); ^;'3(m=  
output.writeLong(fileSplitterFetch.nEndPos); n`6vM4rM)  
} v
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output.close(); )gE:@3  
} 5i0<BZDTef  
catch(IOException e){e.printStackTrace ();} B!:(*lF  
catch(Exception e){e.printStackTrace ();} _M?:N:e  
} }Vt5].TA  
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//读取保存的下载信息（文件指针位置） pl%ag~i5  
private void read_nPos() >o@WT kF]  
{ h' 16"j>  
try{ >y1/*)O9~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wFh{

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int nCount = input.readInt(); RxqXGM`4  
nStartPos = new long[nCount]; %9IM|\ulp  
nEndPos = new long[nCount]; :U~[%]  
for(int i=0;i<nStartPos.length;i++) {pVD`#Tl[  
{  `=oN&!  
nStartPos = input.readLong(); aw(P@9]  
nEndPos = input.readLong(); DY1o!thz)  
} bygwoZ<E  
input.close(); "UE'dWz  
} UXd\Q''  
catch(IOException e){e.printStackTrace ();} pJ{sBp_$  
catch(Exception e){e.printStackTrace ();} _r&#Snp  
}  @521zi  
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private void processErrorCode(int nErrorCode) )J0'We  
{ sx6` g;  
System.err.println("Error Code : " + nErrorCode); ='~C$%  
} es.`:^
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//停止文件下载 u+hzCCwtR  
public void siteStop() R!:1{1  
{ k+&|*!j  
bStop = true; %hY+%^k.  
for(int i=0;i<nStartPos.length;i++) na<g /&  
fileSplitterFetch.splitterStop(); 8G9V8hS1#B  
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}
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} &DgIykqN  
//负责部分文件的抓取 't wMv
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**FileSplitterFetch.java  pCv=rK@  
*/ 2+0'vIw}  
package NetFox; Hf#/o{=~}  
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import java.io.*; fuQ?@F  
import java.net.*; Ehg5u'cj  
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public class FileSplitterFetch extends Thread { F`'e/  
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9v^MZ^Y{  
String sURL; //File URL 8%Pjx7'<  
long nStartPos; //File Snippet Start Position zL1H[}[z+  
long nEndPos; //File Snippet End Position fY\QI =  
int nThreadID; //Thread's ID _uL m!ku  
boolean bDownOver = false; //Downing is over Uc\\..Cf  
boolean bStop = false; //Stop identical (G:$/fK  
FileAccessI fileAccessI = null; //File Access interface o <sX6a9e  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |FH/Q-7[  
{ an.)2*u  
this.sURL = sURL; je.mX/Lpj  
this.nStartPos = nStart; JIDE]f  
this.nEndPos = nEnd; 'H:lR1(,  
nThreadID = id; !qT.D:!@zF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !<@Zf4m  
} ?mnwD]u  
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public void run() 5WY..60K,  
{ A\gj\&B0"  
while(nStartPos < nEndPos && !bStop) T5o9pmD  
{ R|`}z"4C  
#}l}1^$  
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try{ gZ:)l@ Wu  
URL url = new URL(sURL); .BuY[,I+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WC0@g5;1[  
httpConnection.setRequestProperty("User-Agent","NetFox"); v$lP?\P;}X  
String sProperty = "bytes="+nStartPos+"-"; (V}DPA  
httpConnection.setRequestProperty("RANGE",sProperty); s+9q:  
Utility.log(sProperty); g;Bq#/w  
#NwlKZ-  
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InputStream input = httpConnection.getInputStream(); zAS&L%^tV  
//logResponseHead(httpConnection); Gb\}e}TB[  
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{6*h';~  
byte[] b = new byte[1024]; 's+ Fd~'  
int nRead; TAIcp*)ZM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) IYb@@Jzo  
{ xqX~nV#TB  
nStartPos += fileAccessI.write(b,0,nRead); ~%m-}Sxc  
//if(nThreadID == 1) RR*<txdN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1P@&xcvS\  
} =2# C{u.  
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Utility.log("Thread " + nThreadID + " is over!"); "EDn;l-Q  
bDownOver = true; Q];+?Pu.  
//nPos = fileAccessI.write (b,0,nRead); /EA4-#uw  
} 8tY],  
catch(Exception e){e.printStackTrace ();} esWgYAc3{  
} ?&j[Rj0pH  
} x=gZ7$?A  
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Cir==7A0  
//打印回应的头信息 7JQ5OC3  
public void logResponseHead(HttpURLConnection con) JY~s-jxa  
{ ;a*
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for(int i=1;;i++) #92:h6  
{ rX)PN3TD  
String header=con.getHeaderFieldKey(i); Gmf.lHr$%  
if(header!=null) y/
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1.]#FJe  
Utility.log(header+" : "+con.getHeaderField(header)); R4%!W~K  
else &1{RuV
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break; ]+{Cy\*kR  
} bo4 :|Z  
} ebcGdC/%>  
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public void splitterStop() AM#VRRTU  
{ Yy@;
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bStop = true; @
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} mpIRe@#Z  
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} 5rr7lwWZ  
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/* *1$rg?yGf  
**FileAccess.java G29PdmY$<  
*//文件访问(定位，写) c5+oP j  
package NetFox; pej/9{*xg(  
import java.io.*; J$%mG*Y(  
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public class FileAccessI implements Serializable{ . Zrt/;  
U@@#f;&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @kenv3[Lc  
RandomAccessFile oSavedFile; a]>gDDF  
long nPos; 7<<pP  
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public FileAccessI() throws IOException b'pbf  
{ RF
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this("",0); 
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} CS)&A4`8  
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public FileAccessI(String sName,long nPos) throws IOException H[wJ; l  
{ Qx1ZxJz #  
oSavedFile = new RandomAccessFile(sName,"rw"); cpF\^[D  
this.nPos = nPos; 3;zJ\a.+  
oSavedFile.seek(nPos); m"t\@f  
} M`*B/Fh2  
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public synchronized int write(byte[] b,int nStart,int nLen) 2Vxr  
{ Z3<>Z\6D  
int n = -1; #UG|\}Lp  
try{ o3P`y:&  
oSavedFile.write(b,nStart,nLen); 2 :u4~E3  
n = nLen; 22"M#:r$  
} f ?_YdVZ  
catch(IOException e) LYhgBG,
 
{ W$O^IC  
e.printStackTrace (); 9$c0<~B\  
} ^0_*AwIcN  
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return n; $Q{)AN;m  
} LyH8T'C~  
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} 7(rTGd0  
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/* ~Z!xS  
**SiteInfoBean.java <mjH#aSy  
*/ \:mx Ri  
package NetFox; BQ{Gp 2N  
 LKieOgX  
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public class SiteInfoBean { }00mJ]H(  
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private String sSiteURL; //Site's URL $9Hod-Z1  
private String sFilePath; //Saved File's Path tQ_;UQlX  
private String sFileName; //Saved File's Name `e .;P  
private int nSplitter; //Count of Splited Downloading File !/znovoD  
zYO+;;*@  
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public SiteInfoBean() x.qn$?3V]  
{//nSplitter的缺省值为5 EKZ40z`  
//default value of nSplitter is 5 ?v
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this("","","",5);
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} +Gqh  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `Jhu&MWg  
{ ~z#Faed=a  
sSiteURL= sURL; A^ $9[_  
sFilePath = sPath; A\ds0dUE  
sFileName = sName; !;.i#c_u  
this.nSplitter = nSpiltter; xfCq;?MupW  
y K)7%j!  
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} u6IEBYG ((  
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public String getSSiteURL() i`Fg kABw  
{ &?Y
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return sSiteURL; /f~V(DK  
} tX$%*Uy  
s
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public void setSSiteURL(String value) 0M(\xO  
{ u:tLO3VfJ  
sSiteURL = value; O&!>C7  
} z1wy@1o'  
' Z:FGSwT  
+:pjQ1LsJ  
public String getSFilePath() ~f0Bu:A)  
{ 5BR9f3}  
return sFilePath; 0][PL%3Z  
} ))V)]+  
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public void setSFilePath(String value) j:B?0~=  
{ x~C%Hp*#  
sFilePath = value; .vYU4g]  
} \M(0@#-$C  
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public String getSFileName() Cp=DdmR  
{ >Pj ?IE6  
return sFileName; fa9c!xDt  
} E7@0,9AU  
lgFA}p@  
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public void setSFileName(String value) C-'n4AY^  
{ ;4p_lw@  
sFileName = value; [t/7hx"2t  
} ts/rV#s~  
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public int getNSplitter() $,Y\  
{ !4TMgM  
return nSplitter; b!Pz~faXD  
} BC0SSR@e  
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public void setNSplitter(int nCount)
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{ rKg~H=4x2  
nSplitter = nCount; 2<53y~Yi%  
} g>)&Q>}=W  
} q66!xhp;?  
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/* D]n9+!Ec1f  
**Utility.java |2
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*/ ,?g}->ZB  
package NetFox; HLm6BtE  
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public class Utility { 7\I,;swo  
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public Utility() 7(c7-  
{ MQ7d IUs  
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} %GS^=Qr  
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//线程睡眠 ,SQmQ6h  
public static void sleep(int nSecond) A'Q=DoE  
{  _0^f  
try{ g
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Thread.sleep(nSecond); 5n,?&+*L  
}  /6)6  
catch(Exception e) }>~';l  
{ > Q[L,I  
e.printStackTrace (); aVTTpMY  
} ~2 aR>R_nT  
} ZH6#(;b  
4rkj$  
//日志 1=Npq=d  
public static void log(String sMsg) qy@v,a  
{ M.B
0)  
System.err.println(sMsg); '?7?
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} rjsqXo:9  
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public static void log(int sMsg) |VC|@ Q  
{ ~Q<h,P  
System.err.println(sMsg); +<qmVW^X  
} P]V/<8o.53  
} =)tU]kp  
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/* jm~(OLg  
**TestMethod.java
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*/ ,]CZ(q9-  
package NetFox; oqM(?3 yv  
n`'v8 `a]  
79}voDFd  
public class TestMethod { `*?8<Vm  
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+%Y`>1I^#  
public TestMethod() $:&?
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{ ///xx/weblogic60b2_win.exe 2@!Ou$W  
try{ T\}?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); WEX6I16  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @log=^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r
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fileFetch.start(); tzl`|UwF  
} 2Mqac:L  
catch(Exception e){e.printStackTrace ();} d:|(l^]{r  
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} ,V$PV,G  
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/%O+]#$`0  
public static void main(String[] args) ^uG^XY&ItC  
{ Ed&;d+NM  
new TestMethod(); W=Y?_Oz  
} ChVur{jR  
} mv%Zh1khn/  
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