http断点续传简单实现（java)

/* 7"20hAd  
**SiteFileFetch.java a&c6.#E{y  
*/ +l9!Fl{MK\  
package NetFox; 3?V_BUoON  
import java.io.*; c'%-jG)\  
import java.net.*; nxWY7hU  
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public class SiteFileFetch extends Thread { YjxF}VI~<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean lku[dQdk  
long[] nStartPos; //开始位置 =g9*UzA"O  
long[] nEndPos; //结束位置 |wiqGzAr{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $$Oey)*  
long nFileLength; //文件长度 1(I6.BHW  
boolean bFirst = true; //是否第一次取文件 e4HA7=z  
boolean bStop = false; //停止标志 =5/9%P8j9  
File tmpFile; //文件下载的临时信息 8<8:+M}  
DataOutputStream output; //输出到文件的输出流 A OISs4  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -likj#Z  
public SiteFileFetch(SiteInfoBean bean) throws IOException Sjvdirr  
{ `$,GzS(  
siteInfoBean = bean; Ta(Y:*Ri  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [d(U38BI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); K/i*w<aPb7  
if(tmpFile.exists ()) `6lr4Kk @R  
{ NG "C&v  
bFirst = false; D~
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read_nPos(); ="Ho%*@6  
} (tIo:j  
else gy#/D& N[  
{ gtk7)Uh  
nStartPos = new long[bean.getNSplitter()]; @k,z:~[C=  
nEndPos = new long[bean.getNSplitter()]; $8UUzk  
} 3Z5D)zuc  
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} %E#s\B,w  
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v  
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public void run() n>ULRgiT:o  
{ A mNW0.}  
//获得文件长度 Si8p
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//分割文件 }uJu>'1
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//实例FileSplitterFetch }+.}J  
//启动FileSplitterFetch线程 [x+FcXb  
//等待子线程返回 oW ::h
B  
try{ g)#W>.Asd  
if(bFirst) fI&t]  
{ 06O2:5zF  
nFileLength = getFileSize(); B:'J`M"N  
if(nFileLength == -1) TW)c#P43K  
{ h"X;3b^ m  
System.err.println("File Length is not known!"); ,]9P{k]O  
} % tS,}ze  
else if(nFileLength == -2) /t+f{VX$  
{ ~;l@|7wGz  
System.err.println("File is not access!"); ED=V8';D  
} hs^zTZ_  
else tSr8 zAV  
{ B2
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for(int i=0;i<nStartPos.length;i++) &e E=<x  
{ 0z1ifg&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0?s|i :  
} %j.0G`x9 +  
for(int i=0;i<nEndPos.length-1;i++) ',9V|jvK  
{ 't:;irLW.  
nEndPos = nStartPos[i+1]; BXtCSfY$  
} 3{'Ne}5%I  
nEndPos[nEndPos.length-1] = nFileLength; 5rw 7;'  
} [tlI!~Z  
} Bt@^+vH ~  
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//启动子线程 ur)9x^y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Of*Pw[vD  
for(int i=0;i<nStartPos.length;i++) 4ezEW|S  
{ - Ajo9H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ] eotc2?u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), r)y=lAyF>  
nStartPos,nEndPos,i); bo2H]PL*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J\+0[~~  
fileSplitterFetch.start(); &XIt5<$~R  
} [w0QZyUn  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3@kf@Vf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?qPo=~y01  
nEndPos = " + nFileLength); f.D?sHAn  
// fileSplitterFetch[nPos.length-1].start(); MqW7cjg  
dq(uVW^&ae  
a
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//等待子线程结束 \y97W&AN  
//int count = 0; |]jb& M  
//是否结束while循环 J"!vu.[  
boolean breakWhile = false; Sdp&jZY  
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while(!bStop) %RTBV9LIXr  
{ <^&ehy:7y  
write_nPos(); ?9!6%]2D  
Utility.sleep(500); ,)0H3t  
breakWhile = true; Bo)3!wO8  
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for(int i=0;i<nStartPos.length;i++) v\c>b:AofD  
{ e%svrJ2   
if(!fileSplitterFetch.bDownOver) eWCb
73  
{ `#rL*;\uV  
breakWhile = false; j_K
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break; @Xt*Snd  
} ,|3MG",@@h  
} ^X=ar
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if(breakWhile) _GV:HOBi  
break; PRx8I .  
2<i!{;u$qL  
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//count++; BL0 {HV!  
//if(count>4) caIL&G,  
// siteStop(); Z-^LKe  
} Z/W:97M  
+[M6X} TQ  
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System.err.println("文件下载结束！"); CuFSeRe  
} UbXh,QEG*  
catch(Exception e){e.printStackTrace ();} {&cJDqz5=  
} pV9IHs}  
&q3"g*q  
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//获得文件长度 '9laa=H%8  
public long getFileSize() fa-IhB1!K  
{ qB~rQPa  
int nFileLength = -1; \z>f
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try{ `nUXDmdwzO  
URL url = new URL(siteInfoBean.getSSiteURL()); ),0g~'I~D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v_BcTzQ0S  
httpConnection.setRequestProperty("User-Agent","NetFox"); @:j}Jmg  
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int responseCode=httpConnection.getResponseCode(); Hkk/xNP  
if(responseCode>=400) ?Y
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{ uW=k K0E  
processErrorCode(responseCode); ^|/TC!v]M  
return -2; //-2 represent access is error ]3x?  
} EMh7z7}Rr  
4QH3fTv   
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String sHeader; ,
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for(int i=1;;i++) sQ=]NF)\  
{ hB"fhX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {Bk[rCl  
//Utility.log(in.readLine()); riUwBiVa?2  
sHeader=httpConnection.getHeaderFieldKey(i); >W%Em
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if(sHeader!=null) p?*Q- f  
{ iIvc43YV%  
if(sHeader.equals("Content-Length")) 9%k2'iV7  
{ ?8I?'\F;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z
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break; 8LyD7P1\  
} D60aH!ft  
} 6w*dKInG[-  
else x/NfZ5e0X  
break; QCD.YFM  
} :nh_k4S@v  
} ?}Z1bH  
catch(IOException e){e.printStackTrace ();} ?5+.`L9H  
catch(Exception e){e.printStackTrace ();} Cw iKi^m  
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Utility.log(nFileLength); %<)2/|lCd  
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return nFileLength; |EIng0a  
} q2/pNV#  
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j:^#rFD4?  
//保存下载信息（文件指针位置） 9`T)@Uj2n  
private void write_nPos() bbtGXfI+SB  
{ dV*]f$wQ  
try{ +dWDxguE{w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |!1Y*|Q%s  
output.writeInt(nStartPos.length); 8Ry3`ct  
for(int i=0;i<nStartPos.length;i++) ]S&
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{ i)o2klIkB  
// output.writeLong(nPos); ."TxX.&HE  
output.writeLong(fileSplitterFetch.nStartPos); J &o|QG  
output.writeLong(fileSplitterFetch.nEndPos); h2)yq:87  
} zE336  
output.close(); hP=WFD&  
} H~oail{EQ  
catch(IOException e){e.printStackTrace ();} 5/q}`T9i%7  
catch(Exception e){e.printStackTrace ();} cCSs  
} fWCo;4<5?  

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//读取保存的下载信息（文件指针位置） P#E&|n7DT  
private void read_nPos() Yab%/z2:  
{ q YC;cKv  
try{ 6}Vf\j~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9 3U_tQ&1?  
int nCount = input.readInt(); a_[Eh fE  
nStartPos = new long[nCount]; \(J8#V  
nEndPos = new long[nCount]; `uq8G  
for(int i=0;i<nStartPos.length;i++) H ;7(}:.  
{ @D)al^]x6  
nStartPos = input.readLong(); =
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nEndPos = input.readLong(); 8&;UO{  
} pe0F0Ruy
 
input.close(); v&Ii^?CvO  
} f& 0M*o,)  
catch(IOException e){e.printStackTrace ();} \@-@Y  
catch(Exception e){e.printStackTrace ();} f"B3,6m  
} #c!*</  
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private void processErrorCode(int nErrorCode) qBU-~"2t  
{ ~{?_p@&n  
System.err.println("Error Code : " + nErrorCode); n?oW< &  
} ]fm'ZY&  
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//停止文件下载 ,368d9,rDz  
public void siteStop() PvR6 z0  
{ `0rd26Qro  
bStop = true; }Dp*}=?E  
for(int i=0;i<nStartPos.length;i++) SIe="YG]<  
fileSplitterFetch.splitterStop(); Y}@&h!  
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} u=Fv2  
} :fKl]XO  
//负责部分文件的抓取 ylUb9KusOx  
**FileSplitterFetch.java cy*?&~;  
*/ F^l[GdUosK  
package NetFox; 5VRYO"D:  
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import java.io.*; 2^XGGB0  
import java.net.*; 7;u e
 
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public class FileSplitterFetch extends Thread { +O'3|M  
{Z{75}  
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String sURL; //File URL cD@(/$wt  
long nStartPos; //File Snippet Start Position )W|w C#  
long nEndPos; //File Snippet End Position 6.FY0.i  
int nThreadID; //Thread's ID MU>k,:[  
boolean bDownOver = false; //Downing is over "
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boolean bStop = false; //Stop identical /TE_W@?^  
FileAccessI fileAccessI = null; //File Access interface k2E0/ @f{k  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException k[0-CB  
{ (VS5V31"  
this.sURL = sURL; ?xK8#  
this.nStartPos = nStart; mCRt8rY;  
this.nEndPos = nEnd; ?m![Pg%  
nThreadID = id; z,|r*\dw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 TPVVck-T8  
} B! rTD5a  
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public void run() ,/[6e\0~  
{ rMXN[,|v  
while(nStartPos < nEndPos && !bStop) Z/Eb:  
{ <wZQc  
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try{ +nUy,S?43  
URL url = new URL(sURL); m[i
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YZP(tn  
httpConnection.setRequestProperty("User-Agent","NetFox"); P D4Tz!F  
String sProperty = "bytes="+nStartPos+"-"; $ oTdfb  
httpConnection.setRequestProperty("RANGE",sProperty); NHB4y/2  
Utility.log(sProperty); SH3|sXH<  
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-8'C\R|J+  
InputStream input = httpConnection.getInputStream(); Fd#?\r.  
//logResponseHead(httpConnection); aHlcfh9|  
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byte[] b = new byte[1024]; "~`I::'c  
int nRead; Z.d7U~_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FE" y\2}  
{ - *F(7$  
nStartPos += fileAccessI.write(b,0,nRead); Kqun^"Df  
//if(nThreadID == 1) H|,Oswk~-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  zG+R5:  
} 33jovK2  
>
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Utility.log("Thread " + nThreadID + " is over!"); 1D16  
bDownOver = true; ]e>RK'  
//nPos = fileAccessI.write (b,0,nRead); 0MV>"aV  
} h H <J,Wn  
catch(Exception e){e.printStackTrace ();} O#&c6MDB:  
} 0ph{  
} VQY&g;[d  
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b:=TB0Fx?n  
//打印回应的头信息 5'0xz.)!  
public void logResponseHead(HttpURLConnection con) X_qf"|i  
{ g wz7krUTe  
for(int i=1;;i++) rX*H)3F  
{ ;g6M%;1-  
String header=con.getHeaderFieldKey(i); *eIJwXE  
if(header!=null) b'P eH\h{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w0|gG+x jS  
Utility.log(header+" : "+con.getHeaderField(header)); 79nG|Yj|\  
else ~UyV<  
break; 3:5 &Aa!  
} <Gav5Rc  
} iY`%SmB  
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public void splitterStop() sBu=e7  
{ VmCW6 G#M  
bStop = true; \Z^TXyu  
} ii%+jdi.  
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} wx\v:A  
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/* tBNoI  
**FileAccess.java 2LNRtW*  
*//文件访问(定位，写) a,3j,(3  
package NetFox; G+F#n6Vx  
import java.io.*; J~B<7O<?!1  
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public class FileAccessI implements Serializable{ %Rz&lh/  
aaKN^fi&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p`nPhk,:b  
RandomAccessFile oSavedFile; ;2@BO-3K  
long nPos; +zu(  
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public FileAccessI() throws IOException 3ia^
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{ # S}Z8  
this("",0); [~kdPk  
} 48jVRo  
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public FileAccessI(String sName,long nPos) throws IOException Glxuz0]  
{ N;Dni#tQ`  
oSavedFile = new RandomAccessFile(sName,"rw"); z
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this.nPos = nPos; zS\E/.X2  
oSavedFile.seek(nPos); n8uv#DsdK  
} I&MY{f  
a
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public synchronized int write(byte[] b,int nStart,int nLen) u)3 $~m~  
{ 0q.Ujm=,z  
int n = -1; vohoLeJTj  
try{ SfJA(v@E  
oSavedFile.write(b,nStart,nLen); N>Eqj>G  
n = nLen; `(v='$6}  
} /EibEd\  
catch(IOException e) smdZxFl  
{ NB\{'  
e.printStackTrace (); !:|TdYrmj  
} y;t6sM@  
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return n; "]oO{'1X  
} qb5#_1qz+^  
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} %STliJ  
%|^OOU}  
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/* %{(x3\ *&  
**SiteInfoBean.java hX`hs-*qM  
*/ o;W`4S^  
package NetFox; $e\h}A6  
1z&Ly3  
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public class SiteInfoBean { B=>RH!&  
Q:|l`*.R  
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private String sSiteURL; //Site's URL oY1';&BO9  
private String sFilePath; //Saved File's Path '"?C4mbSl  
private String sFileName; //Saved File's Name '"<6.,Ae  
private int nSplitter; //Count of Splited Downloading File {cB+mh;mJ>  
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public SiteInfoBean() U~} U\_  
{//nSplitter的缺省值为5 nSF``pp+  
//default value of nSplitter is 5 uch>AuF:  
this("","","",5); p8kr/uMP ;  
} R)M_|ca  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) pM{nh00[  
{ Z.W66\8~}^  
sSiteURL= sURL; bHhtd_}  
sFilePath = sPath; V?P,&c?
84  
sFileName = sName; ~by]xE1Eg  
this.nSplitter = nSpiltter; UOGuqV-  
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} Nru7(ag1~  
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public String getSSiteURL() jn%
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{
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return sSiteURL; aM@z^<Ub  
} FuUD 61JHY  
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public void setSSiteURL(String value) Y 2
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{ *?z0$Kz<,[  
sSiteURL = value; _(d.!qGz  
} cooUE<a  
6\u!E~zy  
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public String getSFilePath() r6;$1K*0  
{ ZxG}ViS4I  
return sFilePath; '8fk+>M  
} $`8Ar,Xz`  
7}GK%H-u  
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public void setSFilePath(String value) 5aBAr  
{ A%Xt|=^_  
sFilePath = value; Fi.aC;sx  
} Ul_M3"Z  
9U {y1}  
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public String getSFileName() E]J:~H'Er  
{ gP-nluq  
return sFileName; 6vp *9  
} n4R2^gX
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;Og&FFs'  
public void setSFileName(String value) X*g(q0N<S  
{ >Jw6l0z  
sFileName = value; qC_mu)6  
} 8 F2|  
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~ ^>417>  
public int getNSplitter() RQkyCAGx  
{ $55U+)C<  
return nSplitter; X; 5
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} k-E{d04-2  
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public void setNSplitter(int nCount) lJzl6&  
{ tM,%^){p$  
nSplitter = nCount; 'JdkUhq1V  
} WKrX,GF  
} rZoj
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/*
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**Utility.java N7%TYs  
*/ v!42DA)  
package NetFox; ckjrk  
,;<RW]r-P  
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public class Utility { 7 uMd ZpD  
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tu>{  
public Utility() iB1i/l  
{ RGIoI]_  
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} 1z*kc)=JF8  
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//线程睡眠 -h-oMqgu(  
public static void sleep(int nSecond) ,&7Wa-vf  
{  :Pq.,s  
try{ 659v\51*  
Thread.sleep(nSecond); 1/ZR*fa  
} 451'>qS  
catch(Exception e) ?-OPX_i_  
{ F52B~@.  
e.printStackTrace (); F_ 7H!F  
} "BVdPSDBk  
} xMs]Hs  
/u`3VOn  
//日志 9Bdt(}0A  
public static void log(String sMsg) E2AW7f(/  
{ |<`.fOxJP  
System.err.println(sMsg); Aaw(Ed  
} bm}6{28R  
~%ozgzr^  
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public static void log(int sMsg) aF8k/$u  
{ /}5B&TZ=(3  
System.err.println(sMsg);  T7$S_  
} V5D
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} wU`!B<,j  
yg;_.4TpIO  
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/* *zVvQ=  
**TestMethod.java u-DK_^v4M  
*/ Rt(J/%;  
package NetFox; *Q}[ ]g  
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public class TestMethod { ;\y;  
b!$}ma;B  
XD-^w_  
public TestMethod() X6RQqen3:  
{ ///xx/weblogic60b2_win.exe Uh|>Skic4  
try{ GZ}/leR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); b^`AJK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *s)}Bj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {hqAnZ@]vr  
fileFetch.start(); WW "i  
} NvtM3  
catch(Exception e){e.printStackTrace ();} Wv K(G3  
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(A/0@f1#  
} S<6k0b(,_3  
\ Aq;Q?  
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public static void main(String[] args) 59B&286
1  
{ tkuc/Z/@  
new TestMethod(); 8 #oR/Nt  
} #Ogt(5Sd  
} |$hgT K[L  
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