http断点续传简单实现（java)

/* g)f& mQ)  
**SiteFileFetch.java tF[)Y#  
*/ 5_A*IC]  
package NetFox; &y0GdzfQd  
import java.io.*; "E<+idoz  
import java.net.*; aF/DFaiYv  
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public class SiteFileFetch extends Thread { Lapeh>1T  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w\[l4|g`  
long[] nStartPos; //开始位置 d&G]k!|\  
long[] nEndPos; //结束位置 V~jp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L~/L<Ms  
long nFileLength; //文件长度 O\uI
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boolean bFirst = true; //是否第一次取文件 v`L]dY4,  
boolean bStop = false; //停止标志 S~r75] "  
File tmpFile; //文件下载的临时信息 m*1  
DataOutputStream output; //输出到文件的输出流 hrJ(][8  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） W4.w  
public SiteFileFetch(SiteInfoBean bean) throws IOException wIAH,3!  
{ byP<!p*  
siteInfoBean = bean; Y8%l)g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y(aUB$"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -Sh&x  
if(tmpFile.exists ()) L[:AUe  
{ T_s09Wl  
bFirst = false; xC5Pv">  
read_nPos(); gP|-A`y  
} '+l"zK]L-  
else Y6Y"fb%K  
{ 0datzEns`  
nStartPos = new long[bean.getNSplitter()]; 4dN <B U  
nEndPos = new long[bean.getNSplitter()]; X'\h^\yOo  
} UsA fZg8  
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} .*`]x  
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public void run() )RTWt`  
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//获得文件长度 X}]A_G  
//分割文件 ,?jc0L.'r]  
//实例FileSplitterFetch 
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//启动FileSplitterFetch线程 /~".GZ&29  
//等待子线程返回 CvZ\Z472.j  
try{ %2b^t*CQ  
if(bFirst) T(Yp90'6  
{ y'b*Dk{  
nFileLength = getFileSize(); (x\VGo  
if(nFileLength == -1) pl[@U<8aw  
{ (f_YgQEL  
System.err.println("File Length is not known!"); $aU.M3  
} ?%~^PHgZ|  
else if(nFileLength == -2) dR_6j}  
{ NZZy^p&O  
System.err.println("File is not access!"); uD?G\"L i  
} !x ~s`z  
else MCEHv}W  
{ \\13n4fAv  
for(int i=0;i<nStartPos.length;i++) XC;Icr)  
{ 'nM4t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^Lc\{,m  
} {PxFG<^U  
for(int i=0;i<nEndPos.length-1;i++) +C~d;p  
{ YU8]W%  
nEndPos = nStartPos[i+1]; 45wtl/^9  
} +'5I8FE-  
nEndPos[nEndPos.length-1] = nFileLength; eCsk\f`  
} <},JWV3  
} %1jcY0zEQ  
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//启动子线程 x$o^;2Z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $Z;/Sh  
for(int i=0;i<nStartPos.length;i++) IaSpF<&Y;  
{ !dGu0wE  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _h#I}uJ~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7M7Ir\d0lp  
nStartPos,nEndPos,i); j:'g*IxM_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >L!c} Ku  
fileSplitterFetch.start(); /u.ZvY3,  
} p)iEwl}!j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^5
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n}A!aC  
nEndPos = " + nFileLength); 
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// fileSplitterFetch[nPos.length-1].start(); J@$~q}iG  
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V+lF|CZb5  
//等待子线程结束 lD3nz<p  
//int count = 0; `a MU2  
//是否结束while循环 io+V4m  
boolean breakWhile = false; $+7uB-KsU  
q{Z#}|km#  
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while(!bStop) zX&SnT1~  
{ |0=UZK7%O  
write_nPos(); A/'po_'uy  
Utility.sleep(500); \/Mx|7<  
breakWhile = true; esnq/  
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&  
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for(int i=0;i<nStartPos.length;i++) 1Q>nS[  
{ DaQl ip  
if(!fileSplitterFetch.bDownOver) !&rd#ZBn  
{ 3@gsKtA&H4  
breakWhile = false; @9B*V~ <  
break; ]oB
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} h0rPMd(K
 
} +GI906K  
if(breakWhile) \c:$eF  
break; k9;^|Cm k  
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~Ba=nn8Cq  
//count++; CP~ZIIip"  
//if(count>4) P"Al*{:J  
// siteStop(); 8D*nU3O   
} DpT9"?g7  
hF,|()E[  
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System.err.println("文件下载结束！"); {rUg,y{v  
} IW0S*mO$  
catch(Exception e){e.printStackTrace ();} -r={P_E6  
} !ajBZ>Q  
[k6I#v<&  
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//获得文件长度 G](4!G&  
public long getFileSize() _B0(1(M<2  
{ 1[!v{F%]  
int nFileLength = -1; 6c-/D.M  
try{ X8$i*#D  
URL url = new URL(siteInfoBean.getSSiteURL());
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); SiLW[JXd  
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int responseCode=httpConnection.getResponseCode(); ]vvYPRV7
6  
if(responseCode>=400) lG7PM^Eb
 
{ 1M]=Nv  
processErrorCode(responseCode); "v8p<JfB`  
return -2; //-2 represent access is error LhJ
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} ]`/>hH>+~9  
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String sHeader; Q(bOar5  
oD)]4|  
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for(int i=1;;i++) gP2zDI   
{ 3UZd_?JI[^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K*/oWYM]  
//Utility.log(in.readLine()); [,o:nry'a  
sHeader=httpConnection.getHeaderFieldKey(i); v:t;Uk^Y  
if(sHeader!=null) XF!L.'zH  
{ Rx-\B$G  
if(sHeader.equals("Content-Length")) e^y9Kmd  
{ *~#I5s\s!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jIol`WX  
break; {VcRur}&Y8  
} J @Hg7Faz  
} Xw?DN*`L  
else #T=iS(i  
break; Gv-VDRS  
} yf&g
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} C[
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catch(IOException e){e.printStackTrace ();} h^Wb<O`S  
catch(Exception e){e.printStackTrace ();} G+zhL6]F
 
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Utility.log(nFileLength); j4~(
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return nFileLength; GA^hev  
} FM{f{2j  
3&hR#;,"X  
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//保存下载信息（文件指针位置） V*vQNPey  
private void write_nPos() B2;P%B  
{ htBA.eQ  
try{ E
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output = new DataOutputStream(new FileOutputStream(tmpFile)); hb`9Vn\-E  
output.writeInt(nStartPos.length); IiPX`V>RC  
for(int i=0;i<nStartPos.length;i++) Ac:`xk<  
{ H$`U] =s|  
// output.writeLong(nPos); CIW4E  
output.writeLong(fileSplitterFetch.nStartPos); 8E%
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output.writeLong(fileSplitterFetch.nEndPos); ~+Wx\:TT  
} v;,W ^#`  
output.close(); 7`|'Om?'  
} K#R]of~/  
catch(IOException e){e.printStackTrace ();} 7-744wV}Z  
catch(Exception e){e.printStackTrace ();} +( LH!\
{^  
} 'uu*DgEr  
X=QX9Ux?^  
;4 ;gaf  
//读取保存的下载信息（文件指针位置） \BHZRytQF  
private void read_nPos() SU0SsgFB  
{ lNX*s E .  
try{ " MnWd BS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ed=/w6<  
int nCount = input.readInt(); fFJ7Y+^  
nStartPos = new long[nCount]; ZF7n]LgSc&  
nEndPos = new long[nCount]; ]it. R-  
for(int i=0;i<nStartPos.length;i++) )1At/
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{ Wl| i$L)7  
nStartPos = input.readLong(); }a"=K%b<\  
nEndPos = input.readLong(); o/-RGLzAo  
} /stvNIEa  
input.close(); ]L3U2H`7  
} 1>*oN  
catch(IOException e){e.printStackTrace ();} [RBSUOF  
catch(Exception e){e.printStackTrace ();} ct\msG }b:  
} ,!Wo6{'  
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private void processErrorCode(int nErrorCode) An_(L*Qz  
{ -mO#HZIq  
System.err.println("Error Code : " + nErrorCode); ,7V?Kj  
} "L.k m  
=-^A;AO(  
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//停止文件下载 lJ3VMYVrUP  
public void siteStop() eg;r38  
{ >lIzeEW#  
bStop = true; +.Vh<:?
 
for(int i=0;i<nStartPos.length;i++) _i>_Sn1"  
fileSplitterFetch.splitterStop(); `R0~mx&6G  
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} U*+-#  
} k (AE%eA  
//负责部分文件的抓取 d'(n/9K  
**FileSplitterFetch.java O.jm{x!
m  
*/ X>$Wf
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package NetFox; @
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import java.io.*; T"99m^y  
import java.net.*; 4- QlIIf  
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public class FileSplitterFetch extends Thread { by1q"\-,  
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String sURL; //File URL YnnK]N;\x  
long nStartPos; //File Snippet Start Position A< .5=E,/  
long nEndPos; //File Snippet End Position Mq~E'g4#  
int nThreadID; //Thread's ID Q>Ct]JW&  
boolean bDownOver = false; //Downing is over &n,v@ gt  
boolean bStop = false; //Stop identical !84Lvg0&  
FileAccessI fileAccessI = null; //File Access interface e!0xh  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xJ<RQCW$  
{ 64b AWHv  
this.sURL = sURL; gK~Z Ch  
this.nStartPos = nStart; '{0O!y[H6  
this.nEndPos = nEnd; %@%rdrZ  
nThreadID = id; ^XeJZkLEB  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j&dCP
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} T$mT;k  
?1g`'q@T%  
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public void run() I!Dx)>E&  
{ X*#\JF4$i  
while(nStartPos < nEndPos && !bStop) ?VxQ&^|  
{ 7h(  
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try{ |H=5Am  
URL url = new URL(sURL); [qxpu{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f-^*p  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~{g/  
String sProperty = "bytes="+nStartPos+"-"; qm#?DSLap  
httpConnection.setRequestProperty("RANGE",sProperty); :9&@/{W  
Utility.log(sProperty); E\Wd*,/v)  
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InputStream input = httpConnection.getInputStream(); sMAH;'`!Eu  
//logResponseHead(httpConnection); !<h9XccN  
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O>f*D+A-  
byte[] b = new byte[1024];  S\ZCZ0  
int nRead; Ts, U T L  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) QH
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{ [$$R>ELYQ  
nStartPos += fileAccessI.write(b,0,nRead); _ZWU~38PM  
//if(nThreadID == 1) {a>JQW5=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MC-Z6l2  
} 3>5gh8!-  
9]chv>dO)=  
1h162  
Utility.log("Thread " + nThreadID + " is over!"); C<QpUJ`k  
bDownOver = true; ~6u|@pnI  
//nPos = fileAccessI.write (b,0,nRead); bA6^RIf?  
} wko9tdC=U  
catch(Exception e){e.printStackTrace ();} jA@ uV,w  
} ]9<H[5>$R  
} d]_].D$  
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//打印回应的头信息 pxbuZ9w2Q  
public void logResponseHead(HttpURLConnection con) 0aGauG[  
{ -e51/lhpd  
for(int i=1;;i++) fP;I{AiN~  
{ P$O@G$n  
String header=con.getHeaderFieldKey(i); %0u5d$bq  
if(header!=null) &"1_n]JO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Nb0T3\3W  
Utility.log(header+" : "+con.getHeaderField(header)); E9.1~ )  
else ncsk(`lo  
break; :-2sKD y  
} 
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} O"[#g  
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public void splitterStop() hR>`I0|p&  
{ zyK11  
bStop = true; +miL naO~L  
} {Z$]Rj  
/PBK:B  
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} pL.~z  
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/* !?B2OE  
**FileAccess.java rG B*a8  
*//文件访问(定位，写) Vx n-  
package NetFox; YL4yT`*  
import java.io.*; n>lQ:l~  
1(VskFtZF  
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public class FileAccessI implements Serializable{ %8"Aq  
K!G/iz9SB  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (bogAi3<F  
RandomAccessFile oSavedFile; 6A} 45  
long nPos; ns[h_g!j;  
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public FileAccessI() throws IOException J\ 
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{ Ed"p|5~  
this("",0); l'\m'Ioh  
} Or()AzwE@  
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qEPC]es|T  
public FileAccessI(String sName,long nPos) throws IOException eG5xJA^  
{ 9\R+g5  
oSavedFile = new RandomAccessFile(sName,"rw"); ,HW[l.v  
this.nPos = nPos; mLeK7?GL  
oSavedFile.seek(nPos); K&iU+  
} u+]8S
q  
!2g*=oY  
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public synchronized int write(byte[] b,int nStart,int nLen) ^{+_PWn  
{ ;U<rFs40  
int n = -1; Dn.%+im-u  
try{ $C&E3 'O  
oSavedFile.write(b,nStart,nLen); G+Zm  
n = nLen; h!]=)7x;  
} >VvA&p71b  
catch(IOException e) e:WKb9nT  
{ DqBiBH[%h  
e.printStackTrace (); $+[ v17lF  
} "?{=|%mf  
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return n; q{+Pf/M5  
} `9p;LZC1K  
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#?RT$L>n  
} =E-V-?N\  
.OSFLY#[?  
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/* :PDyc(s{  
**SiteInfoBean.java 7,EdJ[CR$  
*/ :5BVVa0oR  
package NetFox; [I5}q
&  
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y^hCO:`l3  
public class SiteInfoBean { jZ>x5 W  
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F>s5<pKAX  
private String sSiteURL; //Site's URL FWDAG$K@0  
private String sFilePath; //Saved File's Path :c`Gh< u  
private String sFileName; //Saved File's Name X_2pC|C  
private int nSplitter; //Count of Splited Downloading File 58o'Q  
MPD<MaW$  
4 oZm0
 
public SiteInfoBean() {E$smX  
{//nSplitter的缺省值为5 j)b[7%
 
//default value of nSplitter is 5 &-hXk!A  
this("","","",5); #8qhl  
} TnQ"c)ta  
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:pvJpu$]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `(o:;<&3  
{ G
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sSiteURL= sURL; `D={l29H  
sFilePath = sPath; k}FmdaPI'  
sFileName = sName; V3<H8pL  
this.nSplitter = nSpiltter; Wg!JQRHtT  
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} q1?}G5a?  
ZfP$6%;_  
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public String getSSiteURL() _UGR+0'Q\  
{ S^T ><C  
return sSiteURL; NWS3-iZ|8  
} }ej>uZVe<  
M)1Y7?r]  
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public void setSSiteURL(String value) &OsO _F  
{ #.j}:  
sSiteURL = value; 9wbj}tN\z  
} ?!HU$>  
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public String getSFilePath() h0a|R4J  
{ }\
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return sFilePath; vb`R+y@  
} j9xu21'
!%  
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2"6bz^>}  
public void setSFilePath(String value) B,A,5SuMk  
{ %z~=Jz^  
sFilePath = value; S`8Iu[Ma  
} OXJ
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/V GI@"^v  
public String getSFileName() [ylRq7^e  
{ /mXxj93UA  
return sFileName; h8dFW"cpC  
} V]NCFG  
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public void setSFileName(String value) Q[{RNab  
{ f@[qS7ok  
sFileName = value; 9y&bKB2,  
} _iL?kf  
XY#.?<"Q8  

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public int getNSplitter() tI)|y?q  
{ #a9O3C/MP  
return nSplitter; 1YK(oRSDn  
} T'{9!By,P  
dIfy!B"  
k!Q{u2  
public void setNSplitter(int nCount) 4*&k~0#t  
{ uP+VS>b  
nSplitter = nCount; WdH/^QvTP  
} A=3L_ #nO  
} xHMFYt+0$G  
v&bG`\!  
G[1\5dK*uR  
/* bf|ePGW?  
**Utility.java j+@3.^vK
 
*/ ]f0OmUHR5i  
package NetFox; sM+~x<}0  
YZ`SF"Bd(  
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public class Utility { n}I?.r@e  
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public Utility() X'-Yz7J?o  
{ 4hODpIF  
N#2ldY *  
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} UKQ"sC  
mf)+ 5On  
//线程睡眠 N!Rt040.%  
public static void sleep(int nSecond) A&bj l[s  
{ _bi)d201  
try{ vaGF(hfTA  
Thread.sleep(nSecond); !~yBzH;K  
} (6Od
  
catch(Exception e) naW!b&:  
{ t:5-Ro  
e.printStackTrace (); (v%24bv  
} U!`iKy-  
} "J`&"_CyZ  
fj))Hnt(|  
//日志 ".tL+A[  
public static void log(String sMsg) 2Jio_Hk  
{ YT Zi[/  
System.err.println(sMsg); KGHSEZi]  
} 8v4 o+wP  
{VL@U$'oI  
 7P7OTN  
public static void log(int sMsg) n+Kv^Y`qxO  
{ 1XMR7liE  
System.err.println(sMsg); <"J]u@|  
} j
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} LWN{  
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/* M .b8 -`V  
**TestMethod.java g4$(%]  
*/ C/Khp +  
package NetFox; M 9t7y  
~lys  
zKO7`.*  
public class TestMethod { H<Oo./8+  
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Ki\.w~Qs  
public TestMethod() '6#G$  
{ ///xx/weblogic60b2_win.exe \ ;npdFy  
try{ Nr4:Gih  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w +t@G`d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); i#]e&Bru5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a/sjW  
fileFetch.start(); 4Z( #;9f  
} -{cHp  
catch(Exception e){e.printStackTrace ();} _h~ksNm5u  
(+> 2&@@<  
}}JMwT  
} pk/#RUfT+  
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Y%s:oHt  
public static void main(String[] args) 2 |s ohF  
{ H5=kDkb  
new TestMethod(); /kW Z 8Z  
} q@|+`>h  
} ,c p2Fac  
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