http断点续传简单实现（java)

/* R*GBxJaw  
**SiteFileFetch.java (iKJ~bJ  
*/ xLed];2G  
package NetFox; yPE3Awh5  
import java.io.*; B/X$ZQ0  
import java.net.*; >5O~S
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[IHo ~  
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public class SiteFileFetch extends Thread { KHx2$*E_  
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;gBR~W  
SiteInfoBean siteInfoBean = null; //文件信息Bean 2]kGDeSr  
long[] nStartPos; //开始位置 1$RJzHS  
long[] nEndPos; //结束位置 ]9_gbQ
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 NL]_;\ h  
long nFileLength; //文件长度 1 b7jNkQ  
boolean bFirst = true; //是否第一次取文件 J4+WF#xI2  
boolean bStop = false; //停止标志 iw#~xel<ez  
File tmpFile; //文件下载的临时信息 {.Qv1oOa  
DataOutputStream output; //输出到文件的输出流 aV5M}:D  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G^B>C  
public SiteFileFetch(SiteInfoBean bean) throws IOException +iQ@J+k  
{ 7R:j^"I@  
siteInfoBean = bean; HGAi2+&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); B*_K}5UO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0 s+X:*C~  
if(tmpFile.exists ()) KBM*7raA  
{ *AV%=  
bFirst = false; \me5"ZU  
read_nPos(); # fqrZ9:@  
} xHt7/8wF  
else A+^okT37r  
{ N.mRay,  
nStartPos = new long[bean.getNSplitter()]; D?#l8  
nEndPos = new long[bean.getNSplitter()]; 
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} $'KQP8M+  
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} mrr]{K  
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public void run() ~AjPa}@ f  
{ /4O))}TX  
//获得文件长度 T1q27I  
//分割文件 +D5gbxZX  
//实例FileSplitterFetch A|LO!P,w  
//启动FileSplitterFetch线程 56JQ h  
//等待子线程返回 6D Xja_lp  
try{ c2NB@T9'v  
if(bFirst) j4,y+9U  
{ ~1;M4K  
nFileLength = getFileSize();  @_f^AQ  
if(nFileLength == -1) 
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{ tC|?Kl7  
System.err.println("File Length is not known!"); uD@ZM  
}  g*a+$'  
else if(nFileLength == -2) `(HvD] l  
{ 7;|"1H:cmw  
System.err.println("File is not access!"); O:#YLmbCN  
} ^vMlRt;  
else M6
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{ <Q(E {c3"  
for(int i=0;i<nStartPos.length;i++) )Zr\W3yWX  
{ T#Q7L~?zY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); WP*}X7IS  
} yZ{yzv'D&  
for(int i=0;i<nEndPos.length-1;i++) Uj;JN}k  
{ ="78#Wfj2  
nEndPos = nStartPos[i+1]; "x R6~8  
} hlL$3.]  
nEndPos[nEndPos.length-1] = nFileLength; ]=t}8H  
} C jf<,x$  
} zc8^#D2y&  
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lIS`_H}  
//启动子线程 zHA::6OgPN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R& t*x  
for(int i=0;i<nStartPos.length;i++) @Dfg6<0  
{ p/ xlR[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /i8OyRpSyk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), r'Wf4p^Xd  
nStartPos,nEndPos,i); la<.B^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kr+p&|.  
fileSplitterFetch.start(); x)=l4A\  
} nBp6uNK[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 27N;>   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _|US`,kfc  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tkZUjQIX  
nEndPos = " + nFileLength); K-:y  
// fileSplitterFetch[nPos.length-1].start(); %:'G={G`QH  
1SztN3'q  
27fLW&b2  
//等待子线程结束 msgR"T3'  
//int count = 0; }O7sP^  
//是否结束while循环 /V09Na,N  
boolean breakWhile = false; l#enbQ`-~  
ya1 aWs~  
:0:Tl/))  
while(!bStop) C0[U}Y/r2  
{ 'UhHcMh:  
write_nPos(); "\EX)u9ze  
Utility.sleep(500); ss%,  
breakWhile = true; B?i#m^S  
~D3S01ecM  
VA[EY`8  
for(int i=0;i<nStartPos.length;i++) oaqH@`  
{ yn}Dj9(q  
if(!fileSplitterFetch.bDownOver) \1G'{#Q  
{ ]O@iT= *3  
breakWhile = false; te(H6c#0  
break; iV/I909*''  
} JD#q6&|  
} =gI41Y]  
if(breakWhile) d~qQ_2M[G  
break; U.,S.WP+d  
NH|I>vyN  
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//count++; dvjj"F'Bf  
//if(count>4) UgAp9$=z  
// siteStop(); KxK,en4)+  
} _Z]l=5d  
0\:=KIY.  
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System.err.println("文件下载结束！"); ={;pg(  
} {Ev
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catch(Exception e){e.printStackTrace ();} Qz(2Iu{E]  
} +Mq\3  
A]!0Z:{h%  
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//获得文件长度 v|(]u3=1_  
public long getFileSize()
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{ w{aGH/LN  
int nFileLength = -1; nRc\!4  
try{ ~Pw9[ycn3  
URL url = new URL(siteInfoBean.getSSiteURL()); j%s,%#al  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pFS@yHs  
httpConnection.setRequestProperty("User-Agent","NetFox"); O8.xt|  
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int responseCode=httpConnection.getResponseCode(); neM.M)0  
if(responseCode>=400) c`;oV-f  
{ Jm<NDE~rw  
processErrorCode(responseCode); syBpF:`-W  
return -2; //-2 represent access is error jKmjZz8L]%  
} 4,LS08&gh  
 Kg';[G\  
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String sHeader; Zb=NcEPGy  
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k)-+ZmMOh  
for(int i=1;;i++) %TQ4ZFD3  
{ 1"Oe*@`pV  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e-y$&[  
//Utility.log(in.readLine()); YCiG~y/~  
sHeader=httpConnection.getHeaderFieldKey(i); n7bVL#Sq[  
if(sHeader!=null) 8c.>6 Hy  
{ g
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if(sHeader.equals("Content-Length")) UxNn5(:sM@  
{ bK%F_v3'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P}8hK   
break; \)/qCeiZ  
} aeUgr!  
} }{N#JTmjB#  
else 'O)v@p "  
break; =h4uN,  
} !6=s{V&r1  
} dPu
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catch(IOException e){e.printStackTrace ();} b
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catch(Exception e){e.printStackTrace ();} DQY1oM)D!  
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Utility.log(nFileLength); C{/U;Ie-b  
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return nFileLength; ivgX o'=  
} f?.VVlD  
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n
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//保存下载信息（文件指针位置） r5s{t4 ;Ch  
private void write_nPos() Z~Q5<A9Jz  
{ tRU/[?!  
try{ !QwB8yK@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L?nhm=D  
output.writeInt(nStartPos.length); U>*@VOgB  
for(int i=0;i<nStartPos.length;i++) Ne+Rs+~4  
{ R?)Yh.vi=t  
// output.writeLong(nPos); pP.`+vPi  
output.writeLong(fileSplitterFetch.nStartPos); (9]1p;  
output.writeLong(fileSplitterFetch.nEndPos); DL V ny]  
} h81giY]  
output.close(); xBxiBhqzF  
} 3y.+03 W  
catch(IOException e){e.printStackTrace ();} Fxa{ 9
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catch(Exception e){e.printStackTrace ();} E|9`J00  
} [xM&Jdf8  
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,Dv*<La`\  
//读取保存的下载信息（文件指针位置） k:?)0Uh%^  
private void read_nPos() ~s&r.6DW  
{ eg*aVb  
try{ q0%QMut%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p
+iNi4y@  
int nCount = input.readInt(); t }4  
nStartPos = new long[nCount]; GjwH C{  
nEndPos = new long[nCount]; !q$VnqFk
 
for(int i=0;i<nStartPos.length;i++) ,K}"o~z  
{ 'yH  
nStartPos = input.readLong(); &V+_b$  
nEndPos = input.readLong(); uSXnf  
} ;Lfn&2G  
input.close(); 3L==p`   
}  cRKLyb  
catch(IOException e){e.printStackTrace ();} Me z&@{  
catch(Exception e){e.printStackTrace ();} u^SInanw  
} cu1!W
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private void processErrorCode(int nErrorCode) VOj7Tz9UD  
{ \1<aBgKi  
System.err.println("Error Code : " + nErrorCode); <[ dt2)%L>  
} L=;T$4+p
  
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*Jcd_D\-(1  
//停止文件下载 ?;Sg,.J  
public void siteStop() #7H0I8  
{ lPz`?Hn  
bStop = true; DW,ERQ^  
for(int i=0;i<nStartPos.length;i++) =k d
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fileSplitterFetch.splitterStop(); 56YqY
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, SUx!o  
} \h[*oeh  
} rhOxyY0  
//负责部分文件的抓取 ~1TT?H  
**FileSplitterFetch.java zK~_e\m  
*/ }#.OJub  
package NetFox; ~h<T0Zc  
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import java.io.*; Rmn|!C%%K  
import java.net.*; 5hEA/G  
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public class FileSplitterFetch extends Thread { z+oy#p6+F.  
hB<(~L?A]  
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String sURL; //File URL b"o\-iUioe  
long nStartPos; //File Snippet Start Position <J~6Q  
long nEndPos; //File Snippet End Position Edc3YSg%;  
int nThreadID; //Thread's ID L}Sb0 o.  
boolean bDownOver = false; //Downing is over /AX)n:,  
boolean bStop = false; //Stop identical t^Bs3;E^  
FileAccessI fileAccessI = null; //File Access interface Q& d;UVp  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException bRFZ:hu l  
{ .(p_YjIA  
this.sURL = sURL; 9`qw,X&AK_  
this.nStartPos = nStart; #(}{*dR  
this.nEndPos = nEnd; ZX-A}  
nThreadID = id; N49{J~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 KJ&I4CU]^  
} Zd)LV
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public void run() Qg1kF^=  
{ dw}ge,bBic  
while(nStartPos < nEndPos && !bStop)
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{ !}mM"|<  
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try{ !RLXB$@`  
URL url = new URL(sURL); W4qT]m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3&[d.,/  
httpConnection.setRequestProperty("User-Agent","NetFox"); StNA(+rT  
String sProperty = "bytes="+nStartPos+"-"; &sn-;r  
httpConnection.setRequestProperty("RANGE",sProperty); x
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Utility.log(sProperty); :zIB3nT^  
/3Y"F"`M.  
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InputStream input = httpConnection.getInputStream(); W
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//logResponseHead(httpConnection); k;Qm%B  
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byte[] b = new byte[1024]; ooa"Th<  
int nRead; {J)gS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) asvM/9  
{ o@$pyU8  
nStartPos += fileAccessI.write(b,0,nRead); OS(Ua  
//if(nThreadID == 1) $WW7,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UY *Z`$  
} ;x|?N*  
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Utility.log("Thread " + nThreadID + " is over!"); ;&w_.j*Is  
bDownOver = true; .db:mSrL  
//nPos = fileAccessI.write (b,0,nRead); lUnC+w#[  
} &F0>V o  
catch(Exception e){e.printStackTrace ();} \,nhGh  
} #K-O<:s=y  
} m=iKu(2xRq  
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//打印回应的头信息 w2!5TKZ`  
public void logResponseHead(HttpURLConnection con) $Vs5d=
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{ {A MAQ  
for(int i=1;;i++) Ql}#mC.>/  
{ 5@bmm]  
String header=con.getHeaderFieldKey(i); d_V7w4lK  
if(header!=null) ygV-Fv>PQ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ey>tUmt6?  
Utility.log(header+" : "+con.getHeaderField(header)); 0x,4H30t(  
else [--] ?Dr  
break; ZD?LsD3  
} \Z/0i|  
} &oVZ2.O#(  
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public void splitterStop() ;,KT+!H$  
{ YpSK|(  
bStop = true; S6yLq|W0  
} pug;1UZ  
'
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} (iO/@iw  
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/* do< N+iK  
**FileAccess.java ?,Wm|x
Y  
*//文件访问(定位，写) dlV HyCW  
package NetFox; FePWr7Ze  
import java.io.*; $L]E< gWrP  
7c'OIY].,  
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public class FileAccessI implements Serializable{ Oh=Kl3xs  
~X) 1!Sr  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6,p;8I  
RandomAccessFile oSavedFile; ?+{qmqN  
long nPos; ot^$/(W  
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public FileAccessI() throws IOException !V0)
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{ 7I@@}A  
this("",0); g.Kyfs4`  
} hy
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public FileAccessI(String sName,long nPos) throws IOException TGG-rA6@Lx  
{ Oim
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oSavedFile = new RandomAccessFile(sName,"rw"); 2\xEMec  
this.nPos = nPos; _7-P8"m  
oSavedFile.seek(nPos); Zdu8axK:  
} G"prq&  
kkV*
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z 2Ao6*%  
public synchronized int write(byte[] b,int nStart,int nLen) rEsGf+4  
{ r}XsJ$  
int n = -1; rx(z::  
try{ lz0'E'%{P  
oSavedFile.write(b,nStart,nLen); FPuF1@K  
n = nLen; 9D& 22hL4  
} Z7?-c  
catch(IOException e) ddeH-Z  
{ m-|~tve  
e.printStackTrace (); Ha!]*wg#  
} nTXM/  
@1peJJ{  
P
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return n; v0~*?m4  
} a)M#O\i`  
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} ^Ea^t.c}_  
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/* Z=/bD*\g  
**SiteInfoBean.java 8` f=Eh  
*/ Eh?,-!SUQn  
package NetFox; F5EsaF'e4  
{ BDUl3T  

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public class SiteInfoBean { \bWo"Yo  
@D&}ZV=J  
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private String sSiteURL; //Site's URL ;1woTAuD  
private String sFilePath; //Saved File's Path T! fF1cpF\  
private String sFileName; //Saved File's Name J@pCF@'  
private int nSplitter; //Count of Splited Downloading File 3%SwCYd  
km#Rh^  
]$a,/Jt  
public SiteInfoBean() 7<3eB)S  
{//nSplitter的缺省值为5 D|R,$v:  
//default value of nSplitter is 5 [H2"z\\u  
this("","","",5); >Sh"/3%q  
} M8' GbF=1  
"G @(AE(  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <gc\,P<ru  
{ \HZ]=B#0  
sSiteURL= sURL; 3a]Omuu|=  
sFilePath = sPath; xp"5L8:C  
sFileName = sName; z>./lu\  
this.nSplitter = nSpiltter; +oMe\wYR$r  
9zK5Y+!  
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} "~zQN(sR"P  
b
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public String getSSiteURL() 1k! xG$g0  
{ Epf[8La  
return sSiteURL; X$4 5<oz  
} 5PU$D`7it  
/SDDCZ`;|c  
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public void setSSiteURL(String value) {Deg1V!x>  
{ i=G.{.  
sSiteURL = value; qdeS*rp\  
} -P>f2It  
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public String getSFilePath() KD5}Nk)t  
{ (qM(~4|`  
return sFilePath; "Gh?hU,WWZ  
} Tp0^dZM+  
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public void setSFilePath(String value) w;p!~o &  
{ MHVHEwr.{  
sFilePath = value; D.\s mk  
} :{Crc   
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public String getSFileName() #YMU}4=:  
{ N6BFs
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return sFileName; pK~K>8\  
} |P"p/iY  
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public void setSFileName(String value) TZ,kmk#
 
{ szy^kj^2  
sFileName = value; m pWmExQ  
} c_xo6+:l  
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public int getNSplitter() Iq-+X3i  
{ W6m oFn  
return nSplitter; +EWfsKz  
} aT %A<'O!  
u~9gR@e2{  
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public void setNSplitter(int nCount) Ox` +Z0)a  
{ `E),G;I  
nSplitter = nCount; /Af:{|'$%  
} 62 biOea  
} u-a*fT  
k-b0Eogp]  
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/* 9)a:8/
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**Utility.java /k(KA [bS  
*/ |\OG9{q  
package NetFox; Zw[A1!T,  
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public class Utility { ;@$B{/Q  
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public Utility() fr1/9E;  
{ $Y!$I.+  
4$=Dq$4z
 
x*A_1_A  
} Ifm|_  
s4RqMO5eI  
//线程睡眠 luyU!  
public static void sleep(int nSecond) 6Y|jK<n?H  
{ ;c'9Xyl-  
try{ Q_bF^4gt  
Thread.sleep(nSecond); eJB !|  
} =?} t7}#  
catch(Exception e) l0m\2Ttf  
{ (bIg6_U7\  
e.printStackTrace (); 2sJj -
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} c8cV{}7Kb  
} {o?+T);Z  
L+}q !'8S  
//日志 ab1qcQ<  
public static void log(String sMsg) \k{UqU+s  
{ g9fS|T  
System.err.println(sMsg); p=Nord  
} 8\BCC1K  
+6=2B0$ r  

X
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public static void log(int sMsg) Mb6#97  
{ &VIX?UngE  
System.err.println(sMsg); W?a2P6mAh  
} K0#kW \4`  
} asDq(J`sQ  
!vU$^>zo~  
0ivlKe%  
/* 5YlY=J  
**TestMethod.java DlkHE8r\  
*/ ?qeBgkL(B^  
package NetFox; JCu3,O!q  
_R!KHi  
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public class TestMethod { :>U2yI  
u.wm;eK[  
fX,L;Se"  
public TestMethod() 7gR8Wr ^  
{ ///xx/weblogic60b2_win.exe 2 0Xqs,  
try{ |fMjg'%{}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,O@xv
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); I*/?*p/I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "p43#  
fileFetch.start(); aI$D qnF4  
} 4~Ptn/ g  
catch(Exception e){e.printStackTrace ();} =)Cqjp  
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} qRg^Bp'VD#  
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public static void main(String[] args) fUh7PF%
 
{ D"WqJcDt  
new TestMethod(); 6N}>@Y5  
} Vy-EY*r|  
} -jc8ku3*  
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