http断点续传简单实现（java)

/* +uGP(ONY  
**SiteFileFetch.java fvBC9^3  
*/ zl8\jP  
package NetFox; I(kIHjV|  
import java.io.*; A
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import java.net.*; ZT-
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public class SiteFileFetch extends Thread { Nm:<rI,^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ,c %gwzU  
long[] nStartPos; //开始位置 Q@.9wEAJ  
long[] nEndPos; //结束位置 _.8]7f`*Gc  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^l2d?v8  
long nFileLength; //文件长度 _TcQ12H 5<  
boolean bFirst = true; //是否第一次取文件 X'Il:SK  
boolean bStop = false; //停止标志 !J?=nSu  
File tmpFile; //文件下载的临时信息 OsSiBb,W79  
DataOutputStream output; //输出到文件的输出流 >`V|`Zi ?  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?}Ptb&Vk(  
public SiteFileFetch(SiteInfoBean bean) throws IOException o?hw2-mH  
{ r_<i*l.  
siteInfoBean = bean; \C\y'H5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); A)a+LW'=u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4Jy,IKPp  
if(tmpFile.exists ()) j<-o{6r  
{ "N:]d*A\  
bFirst = false; V'hz1roe  
read_nPos(); !<^j!'2  
} @DKl<F  
else pO+wJ|f  
{ jJQfCOD$  
nStartPos = new long[bean.getNSplitter()]; p~;z"Z  
nEndPos = new long[bean.getNSplitter()]; (2\ekct ^  
} (>lqp%G~  
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} v&,VC~RN-J  
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public void run() lfhKZX
  
{ DmA!+  
//获得文件长度 "1TM  
//分割文件 qvE[_1QCc  
//实例FileSplitterFetch ['`'&+x&!  
//启动FileSplitterFetch线程 xfQ;5n  
//等待子线程返回 `ZV'7|  
try{
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if(bFirst) t"Rf67  
{ mpJ_VS`  
nFileLength = getFileSize(); zw:b7B]  
if(nFileLength == -1) zYJ`.,#C 5  
{ a9JJuSRC  
System.err.println("File Length is not known!"); Vk=<,<BB  
} A/6nVn  
else if(nFileLength == -2) zQ^[=siZ}  
{ 6C}Z1lZl  
System.err.println("File is not access!"); d#,V^  
} nE.s  
else S5v
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{ g {wPw  
for(int i=0;i<nStartPos.length;i++) j`M<M[C*4N  
{ BnY|t2r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (&x\,19U$  
} J3E:r_+  
for(int i=0;i<nEndPos.length-1;i++) u+FftgA  
{ J-?(sjIX  
nEndPos = nStartPos[i+1]; j'b4Sbs-f  
} 4KB?g7_*  
nEndPos[nEndPos.length-1] = nFileLength; Mo r-$a8  
} #`wfl9tj  
} R.$Y1=U6  
^Iq.0E9_  
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//启动子线程 l),13"?C(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) %R"nm  
{ Q*o4zW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iJ#oI@s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QZP;k!"w  
nStartPos,nEndPos,i); E1[%~Cpw*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3ZZI1_j  
fileSplitterFetch.start(); KywT Oq  
} NT:>.~ah@&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JH,bSb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vxZUtyJfe  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m5
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nEndPos = " + nFileLength); oK[,xqyA  
// fileSplitterFetch[nPos.length-1].start(); e+aQ$1^t  
^?`,f>`M  
7-B'G/PS/  
//等待子线程结束 9Dkgu^`  
//int count = 0; k
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//是否结束while循环 O/@[VPf  
boolean breakWhile = false; l'R`XGT  
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while(!bStop) OPh@H.)^  
{ $$>,2^qr&L  
write_nPos(); : P2;9+v  
Utility.sleep(500); ~qxc!k!w4  
breakWhile = true; 2M`Ni&v  
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for(int i=0;i<nStartPos.length;i++) 
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{ Pk2"\y@q/  
if(!fileSplitterFetch.bDownOver) #r}c<?>Vw  
{ `/iN%ZKum  
breakWhile = false; AIo;\35  
break; |%9~W^b  
} J#nEGl|a  
} $o^}<)DW  
if(breakWhile) B-zt(HG  
break; 1 crjRbi  
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//count++; .=D6<4#t  
//if(count>4) :v48y.Ij7s  
// siteStop(); ;W:Q}[  
} !%=k/|#  
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System.err.println("文件下载结束！"); ]t<%>Z$  
} / nR
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catch(Exception e){e.printStackTrace ();} '?4[w]0J<  
} O#k+.LU  
:oQaN[3>_  
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//获得文件长度 rkp0ej2-  
public long getFileSize() Su^Z{ Ud`  
{ 3e:y?hpeL  
int nFileLength = -1; -z94>}Z=  
try{ B5S1F4
 
URL url = new URL(siteInfoBean.getSSiteURL()); Nrh`DyF0D!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eSf:[^  
httpConnection.setRequestProperty("User-Agent","NetFox"); {^iV<>J  
]5CFL$_Q{  
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int responseCode=httpConnection.getResponseCode(); MDt4KD+bZ  
if(responseCode>=400) .d,Zx  
{ >n62csO  
processErrorCode(responseCode); p`0Tpgi  
return -2; //-2 represent access is error B7C6Mau  
} co|0s+%PBq  
}q
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String sHeader; ,.B8hr@H6-  
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for(int i=1;;i++) uR[i9%=8L(  
{ Z )I4U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #B
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//Utility.log(in.readLine()); a1&^P1.  
sHeader=httpConnection.getHeaderFieldKey(i); lRq!|.C  
if(sHeader!=null) 7[PXZT
  
{ Urr1K)  
if(sHeader.equals("Content-Length")) eX/$[SL[  
{ U
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~Hf,MLMdTf  
break; |ipppE=  
} _4w%U[GT,  
} nNr3'6lz  
else BH1To&ol  
break; Kk#@8h>  
} wO9<An  
} Z'~FZRF  
catch(IOException e){e.printStackTrace ();} t<=L&:<N  
catch(Exception e){e.printStackTrace ();} I&9B^fF6  
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Utility.log(nFileLength); :1I,:L  
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return nFileLength;  E7,\s   
} lPQH_+)Z"  
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//保存下载信息（文件指针位置） 6lGL.m'Ra  
private void write_nPos() (`N/1}vk  
{ ~a}pYLxl  
try{ <f%9w]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); zq#o8))4X  
output.writeInt(nStartPos.length); $}829<gh7  
for(int i=0;i<nStartPos.length;i++) E*$:~w  
{ :>;#/<3{  
// output.writeLong(nPos); J&?kezs  
output.writeLong(fileSplitterFetch.nStartPos); S;C3R5*:  
output.writeLong(fileSplitterFetch.nEndPos); gVc[`(@h  
} 0qv)'[O  
output.close(); oT'XcMn  
} Lv"83$^S9  
catch(IOException e){e.printStackTrace ();} W~qo `r  
catch(Exception e){e.printStackTrace ();} uE2Yn`Ha  
} 7g$t$cZby,  
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//读取保存的下载信息（文件指针位置） UkC\[$-"\  
private void read_nPos() #rC% \  
{ K{c^.&6D  
try{ sC$X7h(Q+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); N=
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int nCount = input.readInt(); ^s-3U  
nStartPos = new long[nCount]; />?d 2?  
nEndPos = new long[nCount]; a;(:iMCi  
for(int i=0;i<nStartPos.length;i++) 8CL05:&  
{ Ce:kMkJ  
nStartPos = input.readLong(); 7D,+1>5^Ne  
nEndPos = input.readLong(); w?[)nlNW  
} 1VeCAx[e  
input.close(); ;4 &~i
 
} Mo/
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catch(IOException e){e.printStackTrace ();} ]loO5  
catch(Exception e){e.printStackTrace ();} er_aol e  
} )\e_I\-  
9/{g%40B^  
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private void processErrorCode(int nErrorCode) ^ZsME,  
{ 1_'ZbZv4h  
System.err.println("Error Code : " + nErrorCode); tn
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} r&qD!l5y  
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//停止文件下载 9H<:\-:  
public void siteStop() gyPF!"!5dq  
{ h(Z7a%_  
bStop = true; /swTn1<Y  
for(int i=0;i<nStartPos.length;i++) P _ SJK  
fileSplitterFetch.splitterStop(); _tjH=Ff$  
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9}4L8?2  
} qIk6S6  
} QMIQy  
//负责部分文件的抓取 _CgD7d  
**FileSplitterFetch.java $6_J`7  
*/ \6N\6=t!A  
package NetFox; ?TXFOr]g]2  
bx@CzXre;  
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import java.io.*; 6Hz=VhQrN  
import java.net.*; oxRu:+N
 
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public class FileSplitterFetch extends Thread { A4#m&o  
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 2}`OjVS  
String sURL; //File URL wxoBq{r;  
long nStartPos; //File Snippet Start Position DCNuvrZ  
long nEndPos; //File Snippet End Position U{ Y)\hR-  
int nThreadID; //Thread's ID A_2ppEG  
boolean bDownOver = false; //Downing is over OTRTa{TB  
boolean bStop = false; //Stop identical 8z+ CYeV  
FileAccessI fileAccessI = null; //File Access interface +"C0de|-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?O_;{(F_  
{ H1X6f7`  
this.sURL = sURL; {{O1C~  
this.nStartPos = nStart; y.>r>o"0  
this.nEndPos = nEnd; {U4%aoBd8  
nThreadID = id; 6PTD%Rf\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,0~'#x>  
} ,e;(\t:  
3 -5^$-7_  
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public void run() ]6%
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{ 3
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while(nStartPos < nEndPos && !bStop) `527vK 6  
{ !6kLg1  
8\[6z0+;  
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try{ m\Dbb.vBvW  
URL url = new URL(sURL); 4Iz~3fqB7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5r.{vQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); K(_n
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String sProperty = "bytes="+nStartPos+"-"; -JcfP+{wS  
httpConnection.setRequestProperty("RANGE",sProperty); ;}r#08I  
Utility.log(sProperty); )37|rB
E  
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InputStream input = httpConnection.getInputStream(); LOp<c<+aW  
//logResponseHead(httpConnection); _/K
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!#>{..}}3  
byte[] b = new byte[1024]; _xbV
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int nRead; 3D\I#g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) lc*<UZR  
{ aK,G6y  
nStartPos += fileAccessI.write(b,0,nRead); P2lj#aQLS  
//if(nThreadID == 1) :imp~~L;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wp} PQw:  
} rHP5;j<]  
-{ZRk[>Z  
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Utility.log("Thread " + nThreadID + " is over!"); (pAGS{{  
bDownOver = true; lwa  
//nPos = fileAccessI.write (b,0,nRead); ]/U)<{6  
} :V8 \^  
catch(Exception e){e.printStackTrace ();} Ix}:!
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} Jz3u r)|  
} Og^b'Kx/  
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M[SWMVN{  
//打印回应的头信息 p0[ %+n%  
public void logResponseHead(HttpURLConnection con) :]:q=1;c  
{ nqr[HFWs  
for(int i=1;;i++) ~ZT(@w  
{ 1{_;`V  
String header=con.getHeaderFieldKey(i); 6VIi nuOW  
if(header!=null)  d':c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <D=U=5  
Utility.log(header+" : "+con.getHeaderField(header)); 58WL8xu  
else ?&"-y)FG  
break; Td?a=yu:J  
} \=i>}Sg  
} @*!8  
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public void splitterStop() U@DIO/C,m`  
{ H htAD Y  
bStop = true; %I?uO( @  
} :H3qa2p  
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} [$f  
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/* r;SA1n#  
**FileAccess.java d'q,:="c  
*//文件访问(定位，写) jgbE@IA@!'  
package NetFox; cjp H hoW  
import java.io.*; n-0RA~5z  
]|'Mf;  
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public class FileAccessI implements Serializable{ 9*U3uyPi  
m&cVda/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^*`hJ48u  
RandomAccessFile oSavedFile; Y2HF  
long nPos; 1r'skmxq  
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6]1cy&SG  
public FileAccessI() throws IOException }HRM6fR1S  
{ a;8q7nC  
this("",0); ~{/"fTif  
} r< sx On  
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public FileAccessI(String sName,long nPos) throws IOException [AA'Ko  
{ \%g# __\  
oSavedFile = new RandomAccessFile(sName,"rw");  ]Vuq
)#  
this.nPos = nPos; AT+7!UGL  
oSavedFile.seek(nPos); \c(R#*0,  
} h0_od/D1r  
oF7o"NHaWa  
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public synchronized int write(byte[] b,int nStart,int nLen) S&^i*R4]  
{ Xz4T_-X8d  
int n = -1; E>NRC\^@  
try{ kLtm_  
oSavedFile.write(b,nStart,nLen); 86y)+h`  
n = nLen; OXAr..  
} ^M
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catch(IOException e) )\ow/XPE  
{ > yk2  
e.printStackTrace (); ?%K7IJ%  
} }]V
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#6* j+SX^  
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return n; 2)cq!Zv  
} bh V.uBH  
}M*yE]LL;Z  
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} 3V2dN)\  
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/* :rR)rj'  
**SiteInfoBean.java v!~tX*q  
*/ AYb-
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package NetFox; a/p} ?!\  
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Pr|BhX  
public class SiteInfoBean { $z[FL=h)?+  
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private String sSiteURL; //Site's URL bYt[/K,  
private String sFilePath; //Saved File's Path 0[E}[{t`  
private String sFileName; //Saved File's Name K;)(fc  
private int nSplitter; //Count of Splited Downloading File "=H(\V  
/h6K"w=='!  
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public SiteInfoBean() cCa+UTxaJ  
{//nSplitter的缺省值为5 }3HN$Fwo  
//default value of nSplitter is 5 Wl?0|{W  
this("","","",5); .!
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} MEKsL7  
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;[)O{%s  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?E +[  
{ Fw.df<  
sSiteURL= sURL; mQd L"caA  
sFilePath = sPath; ykMdH:  
sFileName = sName; n[+$a)$8  
this.nSplitter = nSpiltter; sQ"; t=yC  
Q7#Yw"#G!  

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} 6 rp(<D/_  
q#
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public String getSSiteURL() tleWJR8oc  
{ "@ 1+l&  
return sSiteURL; FW=`Fm@z%%  
} {f1iys'Om  
L*(Sh2=_  
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public void setSSiteURL(String value) FHOF6}if  
{ XiW~? *Z  
sSiteURL = value; X\Gbs=sf6  
} Gv\39+9=  
i0q<,VSl$_  
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public String getSFilePath() to,\sc  
{ 'LX]/D  
return sFilePath; b%wm-p  
} +Z7:(o<  
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XU5GmGu_+  
public void setSFilePath(String value) AJYZ`  
{ }t%2giJ  
sFilePath = value; pE4yx5r5
 
} h[(.  
.QVN&UyZ  
9 `+RmX;m  
public String getSFileName() i&mt-  
{ pOq9J7BS  
return sFileName; XP%/*a
m  
} _jWGwO  

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|\BxKwS^  
public void setSFileName(String value) EBMZ7b-7  
{ as^!c!  
sFileName = value; G0h/]%I  
} qw<~v?{|C  
iy-~CPNB_  
Fa+#bX7  
public int getNSplitter() T|^KG<uPV!  
{ ]5a,%*f+  
return nSplitter; e| Sw+fhy<  
} :meq4!g{1  
B%(-UTQf  
| Kw}S/F  
public void setNSplitter(int nCount) rO[ Zx'a  
{ / n@by4;W  
nSplitter = nCount; tRYi q  
} bIy:~z5   
} _z6" C8W  
*f-8egt-  
wOV}<.W  
/* k#"}oI{< 6  
**Utility.java :{=2ih-}  
*/ \5DOp-2  
package NetFox;  ovsI2  
#`qP7E w  
\Xpq=2`  
public class Utility { N$! Vm(S  
q?$<{Z"  
} m&La4E  
public Utility() ~y" ^t@!E  
{ }@TtX\7(D  

>
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? t_$C,A+  
} :9]"4ktoJ  
w,VUWja  
//线程睡眠 1kczlTF  
public static void sleep(int nSecond) d>h
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{ krecUpo  
try{ DAVgP7h'  
Thread.sleep(nSecond); ^3lEfI<pBm  
} !Ct'H1J-  
catch(Exception e) 94'0X  
{ ^GC 8^f  
e.printStackTrace (); s)5W:`MH?  
} uePa4e!  
} + 0 |d2_]E  
a&C}'e"  
//日志 &O\$=&, h  
public static void log(String sMsg) JW9U&Bj
{  
{ h e1=  
System.err.println(sMsg); \(;X3h  
} 9-hVlQ~|  
EZ)$lw/!J  
M]uO%2  
public static void log(int sMsg) I%tJLdL  
{ :>o2UH  
System.err.println(sMsg); !8}x
6  
} m!sMr^W  
} Uu(FFd~3  
"zx4k8  
hngdeGa  
/* M?.[Rr-uw  
**TestMethod.java r8TNl@Z  
*/ '[`pU>9  
package NetFox; {wCzm  
!~QmY,R  
";*Iwd*V  
public class TestMethod { 't#E-+o  
k*k 9hv?  
|YWX.-aeo  
public TestMethod() [fIElH<  
{ ///xx/weblogic60b2_win.exe g3kF&+2i  
try{ $[M5Vv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); m$H(l4wB>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  IA{I|g<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2`nOYK  
fileFetch.start(); -J(93@X9  
} 'Ej&zh  
catch(Exception e){e.printStackTrace ();} 1gh<nn  
G21cJi*  
7yFV.#K3O  
} .?LP$O=  
Xw]L'+V=  
.TKKjS%8  
public static void main(String[] args) `%Jq^uW  
{ HK4 *+  
new TestMethod(); 0})mCVBY  
} rF)[ Sed:T  
} CSNfLGA
 
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