http断点续传简单实现（java)

/* s`C#=l4  
**SiteFileFetch.java Uvf-h4^J]:  
*/ K!|=)G3.`  
package NetFox; ehxtNjA  
import java.io.*; Yc:b:\0}F6  
import java.net.*; rC_K L  
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public class SiteFileFetch extends Thread { P_-zkw  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2_r}4)z  
long[] nStartPos; //开始位置 >ID 3oi
  
long[] nEndPos; //结束位置 5`x9+XvoN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4 CX*,7LZ  
long nFileLength; //文件长度 >z^T~@
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boolean bFirst = true; //是否第一次取文件 8H;TPa  
boolean bStop = false; //停止标志 DX$`\PA  
File tmpFile; //文件下载的临时信息 L8bq3Q'p  
DataOutputStream output; //输出到文件的输出流 "%f>/k;!h.  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BD4.sd+H,  
public SiteFileFetch(SiteInfoBean bean) throws IOException xR#hU;E}  
{ 7{<F6F^P  
siteInfoBean = bean; /6gRoQ%j  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); L@a-"(TN+
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \SLYqJ~m  
if(tmpFile.exists ()) J)jiI>  
{ WK;p[u?~xi  
bFirst = false; {GWcw<g.B  
read_nPos(); v{% /aw  
} t"0~2R6i  
else a$aI%  
{ {B\.8)&8  
nStartPos = new long[bean.getNSplitter()]; &-cI|  
nEndPos = new long[bean.getNSplitter()]; MIR17%G  
} pQVi&(M  
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} "A/kL@-C  
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public void run() Ccc6 ko_  
{ )@K|Co  
//获得文件长度 Z@I%ppd  
//分割文件 nosEo?{  
//实例FileSplitterFetch m};
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//启动FileSplitterFetch线程 -w@fd]g  
//等待子线程返回 D^&!  
try{ `J-"S<c?_  
if(bFirst) ' >\*  
{ n53}79Uiz  
nFileLength = getFileSize(); aY {.  
if(nFileLength == -1) m   
{ 7#g C(&\A  
System.err.println("File Length is not known!"); F`u{'w:Hv  
} #;mZ3[+i5  
else if(nFileLength == -2) Oi7=z?+j  
{ ;<&s_C3  
System.err.println("File is not access!"); X&p-Ge1>z  
} 3_ zI$Z  
else %pwm34  
{ MfL q h  
for(int i=0;i<nStartPos.length;i++) ^k)f oD  
{ +=}% 7o  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); e.HN%LrhS  
} <0kRky$  
for(int i=0;i<nEndPos.length-1;i++) Q?Nzt;)!.  
{ (c}0Sg  
nEndPos = nStartPos[i+1]; {M%"z,GL7J  
} )>[(HxvfJU  
nEndPos[nEndPos.length-1] = nFileLength; d>AVUf<o~  
} 8\a)}k~4  
} a"&Z!A:Z=  
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//启动子线程 hCo&SRC/5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lN1zfM  
for(int i=0;i<nStartPos.length;i++) & 9?vQq|%  
{ C8t+-p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \`XJz{Lm]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =riP~%_ML)  
nStartPos,nEndPos,i); aIfog+Lp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); *e8V4P  
} {T^'&W>8G8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FF_$)%YUp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); XsR%_eT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +2?0]6EQ  
nEndPos = " + nFileLength); jOuv\$  
// fileSplitterFetch[nPos.length-1].start(); Y3Qq'FN!I  
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//等待子线程结束 6F(
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//int count = 0; IIu3mX
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//是否结束while循环 Zq`bd55~  
boolean breakWhile = false; ,v6Jr3  
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while(!bStop) i5wA=K_  
{ @qe>ph[UA  
write_nPos(); Xt7'clr  
Utility.sleep(500); 21WqLgT3 4  
breakWhile = true; NrU-%!Aw  
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for(int i=0;i<nStartPos.length;i++) j)]'kg  
{ nAX|=qp#  
if(!fileSplitterFetch.bDownOver) -s)2b ;  
{ lLJb3[ e.  
breakWhile = false; \W\6m0-
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break; KXM-GIRUG  
} YVaQ3o|!  
} 2h:f6=)r/u  
if(breakWhile) 54;iLL  
break; |knP  
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//count++; k}O|4*.BT  
//if(count>4) H@3+K$|v  
// siteStop(); U'lD|R,g  
} GHlra^  
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System.err.println("文件下载结束！"); 'w!gQ#De  
} h1kPsgzR  
catch(Exception e){e.printStackTrace ();} N Hh  
} jK=*~I  
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//获得文件长度 Nb8<8O ^  
public long getFileSize() E*I

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{ V*m)h  
int nFileLength = -1; TZP{=v<
 
try{ mQvKreo~  
URL url = new URL(siteInfoBean.getSSiteURL()); _Pz3QsV9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~^euaOFU 6  
httpConnection.setRequestProperty("User-Agent","NetFox"); X@Bpjg  
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int responseCode=httpConnection.getResponseCode(); xWwPrd  
if(responseCode>=400) (g)@wNBW  
{ e-')SB  
processErrorCode(responseCode); 6^aYW#O<Ua  
return -2; //-2 represent access is error *~cs8<.!1  
} 6m" 75  
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String sHeader; M+E5PZ|_  
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for(int i=1;;i++) /SKr.S61e  
{ 'f}S,i +q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]p*) PpIl  
//Utility.log(in.readLine()); vedMzef[@>  
sHeader=httpConnection.getHeaderFieldKey(i); oU@ljSD  
if(sHeader!=null) _%2Umy|  
{ ZYt
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if(sHeader.equals("Content-Length")) <D dHP  
{ 0V#t ;`Q3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7, 13g)  
break; 9HE(*S  
} w.Vynb  
} 5p|@)  
else }J?fJ(  
break; I:_*8el&d  
} \l:g{GnoT  
} 0xxzhlKNL  
catch(IOException e){e.printStackTrace ();} A]+h<Y~}  
catch(Exception e){e.printStackTrace ();} @NNLzqqY  
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Utility.log(nFileLength); B R:  
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return nFileLength; &o/4hnHYt  
} BXo|CITso  
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//保存下载信息（文件指针位置） B#?2,  
private void write_nPos() tvOAN|+F  
{ ~0-764%  
try{ UBi4itGD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); VqL 5f  
output.writeInt(nStartPos.length); ,/:a77  
for(int i=0;i<nStartPos.length;i++) &7T H V  
{ P082.:q"  
// output.writeLong(nPos); 2E2}|: ||&  
output.writeLong(fileSplitterFetch.nStartPos); rH9}nL  
output.writeLong(fileSplitterFetch.nEndPos); bXH^Bm  
} 0#[f2X62B  
output.close(); @,4%8E5  
} Uo}&-$B  
catch(IOException e){e.printStackTrace ();} i+[3o@  
catch(Exception e){e.printStackTrace ();} '= <`@  
} <gdgcvd  
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//读取保存的下载信息（文件指针位置） /plUzy2Yu  
private void read_nPos() ]kkBgjQbS  
{ 8KtgSash  
try{ G\+nWvV7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L{LU
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int nCount = input.readInt(); S%X\,N  
nStartPos = new long[nCount]; MXF"F:-Kn  
nEndPos = new long[nCount]; H~|%vjH  
for(int i=0;i<nStartPos.length;i++) }#G"!/ZA0:  
{ _Hu2[lV  
nStartPos = input.readLong(); R5eB,FN  
nEndPos = input.readLong(); -t6R!ZI  
} p,iCM?[|  
input.close(); zf,%BI[Hr  
} 3rdfg  
catch(IOException e){e.printStackTrace ();} KKjxg7{K  
catch(Exception e){e.printStackTrace ();} +z=%89GJ  
} m6r )Z5}f  
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private void processErrorCode(int nErrorCode) [-t> G!)  
{ vaR
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System.err.println("Error Code : " + nErrorCode); dA} 72D?  
} Dw`m>'J0  
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//停止文件下载 v"r9|m~'  
public void siteStop() sk ?'^6Xh  
{ pTALhj#,  
bStop = true; `GQiB]Z  
for(int i=0;i<nStartPos.length;i++) ,![Du::1  
fileSplitterFetch.splitterStop(); ZJ9Jf2 c  
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} 
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} XU_,Z/Yw_  
//负责部分文件的抓取 <.WM-Z  
**FileSplitterFetch.java zNny\Z  
*/ M7DLs;sD  
package NetFox; FGwnESCC  
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import java.io.*; 'xbERu(Y  
import java.net.*; N<06sRg#  
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public class FileSplitterFetch extends Thread { GwQZf|  
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;4G\]%c)E{  
String sURL; //File URL Fi'M"^:r{  
long nStartPos; //File Snippet Start Position z
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long nEndPos; //File Snippet End Position KR=d"t Qw  
int nThreadID; //Thread's ID 2]D$|M?$~  
boolean bDownOver = false; //Downing is over 'cZMRRc<  
boolean bStop = false; //Stop identical =zm0w~']E!  
FileAccessI fileAccessI = null; //File Access interface V3mjbH>F  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .%?-As  
{ -XVEV  
this.sURL = sURL; !ww:O|0  
this.nStartPos = nStart; j/H>0^  
this.nEndPos = nEnd; +YkW[a\4  
nThreadID = id; i_=?eUq%q/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %o@['9U[j  
} 2f19W# '0  
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public void run() Q1`<fD  
{ f v E+.{  
while(nStartPos < nEndPos && !bStop) rFmKmV  
{ dG\U)WA(p  
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try{ Jcz]J)|5v  
URL url = new URL(sURL);
@S}/g/+2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b96t0w!cs  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7uPZuXHxcu  
String sProperty = "bytes="+nStartPos+"-"; r$GPYyHK  
httpConnection.setRequestProperty("RANGE",sProperty); R9Sf!LR  
Utility.log(sProperty); /l,+oG%\  
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InputStream input = httpConnection.getInputStream(); d>%gW*  
//logResponseHead(httpConnection); oX'0o 'c  
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byte[] b = new byte[1024]; 6a4'xq7  
int nRead; 8]q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) CmEpir{}(  
{ O^9CV*]!n  
nStartPos += fileAccessI.write(b,0,nRead); zL:&Q<  
//if(nThreadID == 1) jR{-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R
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} .
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Utility.log("Thread " + nThreadID + " is over!"); b?_e+:\UV  
bDownOver = true; {=UFk-$=  
//nPos = fileAccessI.write (b,0,nRead); h+,'B&=|_  
} d_Q*$Iz)3  
catch(Exception e){e.printStackTrace ();} #zON_[+s9  
} qWsylC23  
} >Z+"`"^o}  
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//打印回应的头信息 O: ,$%  
public void logResponseHead(HttpURLConnection con) }]AT _bh,  
{ @j O4EEe:  
for(int i=1;;i++) q7X}MAW  
{ r&}(9Cq&"y  
String header=con.getHeaderFieldKey(i); U1ZIuDg'E  
if(header!=null) KH7VR^;mk  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qysTjGwa]  
Utility.log(header+" : "+con.getHeaderField(header)); iI5+P`sE&J  
else fUC9-?(K  
break; KZ=
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} &V'519vmoZ  
} CuH2E>wz  
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public void splitterStop() 9O;cJ)tXY  
{ hAm/mu  
bStop = true; %2f//SZ:  
} NJtQx2Sd'H  
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} +l`65!"  
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/* w OI^Q~  
**FileAccess.java -fE.<)m=!  
*//文件访问(定位，写) vCw<G6tD  
package NetFox; xc9YM0B&  
import java.io.*; @@I7$*  
~q)u(WC|  
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public class FileAccessI implements Serializable{ (n,u|}
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C{EAmv'  
RandomAccessFile oSavedFile; 3j
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long nPos; r-}-C!  
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7 8Vcu'j&_  
public FileAccessI() throws IOException hi ~}  
{ S,)d(g3>  
this("",0); k1)%.pt%  
} ? B@&#E!/f  
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rL

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public FileAccessI(String sName,long nPos) throws IOException 9'?se5\  
{ 98RKCc9h  
oSavedFile = new RandomAccessFile(sName,"rw"); ~@T<gA9V  
this.nPos = nPos; IOL L1ar
 
oSavedFile.seek(nPos); Q_]d5pl  
} 7p.>\YtoR}  
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public synchronized int write(byte[] b,int nStart,int nLen) 41G5!=i  
{ 5G(3vRX|1  
int n = -1; .%}?b~   
try{ 7tNc=,x}  
oSavedFile.write(b,nStart,nLen); rq sdE  
n = nLen; `:eU.  
} |
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catch(IOException e) #sTEQjJ,J  
{ 5c5oSy+  
e.printStackTrace (); pd3,pQ  
} Z&Y=`GOI  
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return n; &$'z  
} \8S~c8Z~  
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} 0fm*`4Q  
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5!I4
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/* Q8D&tJg  
**SiteInfoBean.java lhH`dG D
 
*/ a2w T6jY  
package NetFox; Ml?~ |_  
j'?7D0>  
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public class SiteInfoBean {  7I=C+  
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private String sSiteURL; //Site's URL ujFzJdp3k  
private String sFilePath; //Saved File's Path s&a1y~rv  
private String sFileName; //Saved File's Name Aw5pd7qKL  
private int nSplitter; //Count of Splited Downloading File a(IY\q[Wh  
*T`-|H*6@  
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public SiteInfoBean() yF13Of^l./  
{//nSplitter的缺省值为5 :O-iykXyI  
//default value of nSplitter is 5 <IJu7t>  
this("","","",5); (xl\J/  
} d>0+A)6>  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $P z`
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{ ,CvG 20>  
sSiteURL= sURL; <eN_1NTH_  
sFilePath = sPath; 'sh~,+g  
sFileName = sName; j}1zdA  
this.nSplitter = nSpiltter; mYxyWB  
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} NTo!'p:s  
vb Y3;+M>  
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public String getSSiteURL() =<}<Ny  
{ K+*Q@R D  
return sSiteURL; 6$U]9D  
}
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j.e0;! (L}  
public void setSSiteURL(String value) hR#-u1C  
{ F&RgT1*  
sSiteURL = value; L<
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} = ?D(g  
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}`(N:p  
public String getSFilePath() ;0rGiWC#  
{ 'e)^m}:?D  
return sFilePath; j/`94'Y  
} dU)]:>Uz  
a"N4~?US  
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public void setSFilePath(String value) ldha|s.*  
{ r;BT,jiX  
sFilePath = value; +mj*o(  
} te
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public String getSFileName() N;Dp~(1 J1  
{ >F1kR\!  
return sFileName; dZ#&YG)?e  
} {7u[1[L1  
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public void setSFileName(String value) N`iwC!  
{ PZxAH9 S?  
sFileName = value; <+MyZM(z>  
} ]i(-I <`  
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9.'h^#C  
public int getNSplitter() [(Xy.L7x  
{ *IgE
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return nSplitter; |-sPLU&s%  
} F+R?a+e  
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L}  
public void setNSplitter(int nCount) j',W 64  
{ k@zy  
nSplitter = nCount; 0a8/B>  
} XO#/Fv!  
} vEf4HZ&w  
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/* {{V8;y  
**Utility.java !cKz7?w  
*/ =qN2Xg/  
package NetFox; rpeJkG@+  
SJD@&m%?[  
9T#;,{VQ  
public class Utility { P96pm6H_;  
+]=e;LN$0  
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public Utility() fYKOJ5f  
{ C{TA.\   
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" \I4u{zC  
} "KcA  
n>@oBG)!  
//线程睡眠 W3`>8v1?o  
public static void sleep(int nSecond) pv|Pm  
{ f{SB1M   
try{ @`\VBW  
Thread.sleep(nSecond); (&/2\0QV  
} }VDqj}is  
catch(Exception e) hW{j\@R  
{ *s@Qtgu  
e.printStackTrace (); U qG .:@T  
} +`3!I  
} V_plq6z  
P[s8JDqu  
//日志 fw ,
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public static void log(String sMsg) ^C2\`jLMY  
{ U,nEbKJgk  
System.err.println(sMsg);  KWLbD#  
} WJI[9@^I~  
A?Bif;  
EC
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public static void log(int sMsg) /}-CvSR  
{ ^vG8#A}]  
System.err.println(sMsg); 6e&>rq6C  
} >0Q|nCx  
} ~]ZpA-*@Ut  
N !TW!  
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/* R|i/lEq  
**TestMethod.java
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*/  i2~  
package NetFox; V5}B:SUB  
s-dLZ.9F  
2<M= L1\  
public class TestMethod { Df3rV'/~  
6uKTGc4  
&89oO@5  
public TestMethod() 0uBl>A7qhn  
{ ///xx/weblogic60b2_win.exe 2NB L}x  
try{ i<pk6rO1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5dZ|!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1sYEZO;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m3o,@=b  
fileFetch.start(); O%r;5kP  
}
;WldHaZ9r  
catch(Exception e){e.printStackTrace ();} ^MBm==heL  
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~c6}
 
} Ivb4P`{  
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#s!'+|2n  
public static void main(String[] args) TX#m&vh  
{ z({hiVs  
new TestMethod(); _{M\Bs2<  
} z0/} !  
} ^e+
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