http断点续传简单实现（java)

/* oqba:y;AR  
**SiteFileFetch.java pPqN[OJ  
*/ :bRR(sP  
package NetFox; Kk>qgi$  
import java.io.*; 5\0.[W
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import java.net.*; %hbLT{w  
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public class SiteFileFetch extends Thread { p@Y$eZ:O  

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SiteInfoBean siteInfoBean = null; //文件信息Bean 4)HWPX  
long[] nStartPos; //开始位置 P"h\7V,d%  
long[] nEndPos; //结束位置 RzRvu]]8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p=+*g.,O  
long nFileLength; //文件长度 O^Vy"8Ji}y  
boolean bFirst = true; //是否第一次取文件 Tn0l|GRuZA  
boolean bStop = false; //停止标志 n&m?Bu
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File tmpFile; //文件下载的临时信息 (}X?v`Y^W  
DataOutputStream output; //输出到文件的输出流 >&vO4L  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'e>sHL  
public SiteFileFetch(SiteInfoBean bean) throws IOException bo;pj$eR3R  
{ -;)SER3Wq4  
siteInfoBean = bean; 46Q;F  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s#4ew}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zng` oFD  
if(tmpFile.exists ()) iQ!  
{ 7ml0  
bFirst = false; y)/$ge_U  
read_nPos(); };m7FO  
} Ui|a}`c  
else Z;y}gv/{  
{ As'M39*V  
nStartPos = new long[bean.getNSplitter()]; 3{4/7DcX  
nEndPos = new long[bean.getNSplitter()]; Sq|1f?_gU  
} =x0"6gTz>  
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} N9=r#![>,  
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public void run() "
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{ 2]NAs9aZ  
//获得文件长度 gLaO#cQ%  
//分割文件 \8*,&ak%  
//实例FileSplitterFetch ,AbKxT f2  
//启动FileSplitterFetch线程 0"
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//等待子线程返回 9U<)_E<y  
try{ SZ2q}[o`R  
if(bFirst) Hx
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{ vYSetAdv  
nFileLength = getFileSize(); d0A\#H_&  
if(nFileLength == -1) Ef`5fgp? S  
{ sK 1m9  
System.err.println("File Length is not known!"); [B~zoB(  
} L.0} UXd  
else if(nFileLength == -2) 32 1={\X  
{ 2Ph7qEBQ22  
System.err.println("File is not access!"); a4jnu:e  
} ~6:LUM  
else '!fFI1s  
{ LA+$_U"Jk  
for(int i=0;i<nStartPos.length;i++) 6PJJ?}P^1  
{ "_1-IE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )qyx|D  
} $uUb$8Bu  
for(int i=0;i<nEndPos.length-1;i++) moVa'1ul  
{ g;-+7ViIr  
nEndPos = nStartPos[i+1]; BH#C<0="  
} StyB"1y  
nEndPos[nEndPos.length-1] = nFileLength;
w{r(F`  
} gl9pgY1ni  
} @r/Id
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8XYD L]I'  
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//启动子线程 u_
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; g8+4$2`ny  
for(int i=0;i<nStartPos.length;i++) _PyW=Tj  
{ T`g?)
/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Lf; ta  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  &6\r  
nStartPos,nEndPos,i); V|3yZ8lE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8)W?la8'p  
fileSplitterFetch.start(); ^/%o%J&Hz  
} 17i<4f#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z<oE!1St  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j$|j8?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W>?f^C!+m  
nEndPos = " + nFileLength); hB P$9GR  
// fileSplitterFetch[nPos.length-1].start(); C`2*2Y%xkG  
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//等待子线程结束 + 9\:$wMN  
//int count = 0; 8Fd1;G6  
//是否结束while循环 uv|eVT3jNs  
boolean breakWhile = false; "$~}'`(]  
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while(!bStop) agU%z:M{  
{ N"YK@)*Q  
write_nPos(); n&0mz1rw  
Utility.sleep(500); ~{7zm"jN  
breakWhile = true; {WYu0J@  
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for(int i=0;i<nStartPos.length;i++) `P^u:  
{ &547`
*  
if(!fileSplitterFetch.bDownOver) BaWQ<T8p8  
{ 60hNCVq%  
breakWhile = false; Q? <-`7  
break;
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} =E [4H  
} :(bdI]  
if(breakWhile) 3{NaZIk  
break; DA+A >5/  
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//count++; V17>j0Ev$W  
//if(count>4) HF&h  
// siteStop(); KjFZ  
} ig{A[7qN  
|~@x4J5,  
--in+  
System.err.println("文件下载结束！"); t(J![wB}  
} U8-Q'1IT&  
catch(Exception e){e.printStackTrace ();} j>$=SMc  
} J
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//获得文件长度 l`9t}  
public long getFileSize() m"eteA,"k_  
{ 6A R2htN^  
int nFileLength = -1; q!~ -(&S  
try{ a?h*eAAc.  
URL url = new URL(siteInfoBean.getSSiteURL()); Hh;:`;}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gY-5_Ab  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7r#ymQ  
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int responseCode=httpConnection.getResponseCode(); da!P0x9p  
if(responseCode>=400) ]y{WD=T  
{ OPJ: XbG  
processErrorCode(responseCode); NE2pL@sk  
return -2; //-2 represent access is error -_OS%ARa  
} & WOiik  
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String sHeader; VSX@e|Nj  
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] ]U<UJ  
for(int i=1;;i++) Z4K+ /<I  
{ CBYX]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); PQmq5N6  
//Utility.log(in.readLine()); 75T_Dx(H  
sHeader=httpConnection.getHeaderFieldKey(i); h"mi"H^o  
if(sHeader!=null) <yA}i"-1W  
{ 38ES($  
if(sHeader.equals("Content-Length")) ]va>ex$d  
{ _n8GWBi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); q<W=#Sx  
break; N7r_77%m0  
} `$LWmm#  
} 6DIZ@oi  
else g6t"mkMY L  
break; ,QIF
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}  +ECDD'^!  
} o Pci66  
catch(IOException e){e.printStackTrace ();} g:l.MJT  
catch(Exception e){e.printStackTrace ();} [&[^G25  
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Utility.log(nFileLength); 620%Z*   
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return nFileLength; 3f Xv4R;!:  
} \`V$ 'B{.  
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//保存下载信息（文件指针位置） D%mXA70  
private void write_nPos()
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{ +6$g!S5{  
try{ vr^~yEr  
output = new DataOutputStream(new FileOutputStream(tmpFile)); qLL,F  
output.writeInt(nStartPos.length); [H\:pP8t  
for(int i=0;i<nStartPos.length;i++) 54;J8XT7  
{ 0kQPJWF  
// output.writeLong(nPos); ]r!>{  
output.writeLong(fileSplitterFetch.nStartPos); F;ZSzWq  
output.writeLong(fileSplitterFetch.nEndPos); 0 S_':r   
} , ^F)L|  
output.close(); sbkQ71T:  
} '3]p29v{  
catch(IOException e){e.printStackTrace ();} g[ 0<m#"  
catch(Exception e){e.printStackTrace ();} v0Dq@Q1  
} ,B(7\  
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//读取保存的下载信息（文件指针位置） 9Etz:?)b  
private void read_nPos() PjT=$]  
{ .roqEasu8  
try{ v8gdU7Ll,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (6CN/A{qe  
int nCount = input.readInt(); E9|eu\  
nStartPos = new long[nCount]; n,HE0Zn]Y_  
nEndPos = new long[nCount]; OH^N" L  
for(int i=0;i<nStartPos.length;i++) l.\r
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{ ECdvX0*a  
nStartPos = input.readLong(); 1aVa0q<  
nEndPos = input.readLong(); J`q]6qf#  
} pMg3fUIM  
input.close(); zsU=sTsL  
} ?&LZB}1R  
catch(IOException e){e.printStackTrace ();} \$aF&r<R  
catch(Exception e){e.printStackTrace ();} 9`jcC-;iv  
} fJ\sguZ  
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private void processErrorCode(int nErrorCode) -7/s]9o'  
{ O1 .w,U   
System.err.println("Error Code : " + nErrorCode); <^b7cOFQ
 
} G2LK]  

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(Rk_-9_E.  
//停止文件下载 scuHmY0  
public void siteStop() ,P'P^0qJ  
{ >&g}7d
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bStop = true; RjF'x  
for(int i=0;i<nStartPos.length;i++) QIN."&qC^  
fileSplitterFetch.splitterStop(); ri`R<l8  
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} ;N B:e  
} <2!v(EkI  
//负责部分文件的抓取 >{eCh$L  
**FileSplitterFetch.java g~7Ri-"  
*/ FJ*i\Q/D  
package NetFox; ]sz
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import java.io.*; 4!asT;`'  
import java.net.*; Q6o(']0  
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i |{Dd%4vK  
public class FileSplitterFetch extends Thread { `r5$LaD  
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String sURL; //File URL c`lJu_  
long nStartPos; //File Snippet Start Position 48|s$K^  
long nEndPos; //File Snippet End Position O\K_q7iO6  
int nThreadID; //Thread's ID ;!o]wHmA  
boolean bDownOver = false; //Downing is over y@j,a  
boolean bStop = false; //Stop identical ) xbO6V  
FileAccessI fileAccessI = null; //File Access interface Tu{h<Zy  
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2j(h+?N7k  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException fgNU03jp^x  
{ K.G$]H  
this.sURL = sURL; =.y*_Ja  
this.nStartPos = nStart; pA{ 5V9
 
this.nEndPos = nEnd; *Nyev]8  
nThreadID = id; ^qCkt1C-M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LG~S8u  
} Cv$ S
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public void run() ^gV
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{ 8Qh#)hiW!  
while(nStartPos < nEndPos && !bStop)  $Vc~/>  
{ ut>4U'.H  
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try{ |AlR^N  
URL url = new URL(sURL); :16P.z1L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T!wo2EzE  
httpConnection.setRequestProperty("User-Agent","NetFox"); Te2zK7:  
String sProperty = "bytes="+nStartPos+"-"; < RCLI|  
httpConnection.setRequestProperty("RANGE",sProperty); g8!wb{8?s  
Utility.log(sProperty); HTe<x  
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InputStream input = httpConnection.getInputStream();
| ohL]7b<  
//logResponseHead(httpConnection); Q]rD}Ckv-  
b 1&i#I?{  
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byte[] b = new byte[1024]; 9]t[J_YM  
int nRead; BmHwu{n'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [-&L8Un  
{  )1g"?]  
nStartPos += fileAccessI.write(b,0,nRead); #fj/~[Ajv  
//if(nThreadID == 1) 2F%W8Y3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #W.vX?-'0  
} y=Mq(c:'UN  
b':|uu*/  
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Utility.log("Thread " + nThreadID + " is over!"); 0l;<5  
bDownOver = true; 7PR#(ftz  
//nPos = fileAccessI.write (b,0,nRead); 8Ld:"Y#  
} 0 ugT2%  
catch(Exception e){e.printStackTrace ();} "O8gJ0e  
} \5Vde%!$Z  
} Hi_G  
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$A3<G-4O  
//打印回应的头信息 /6O??6g  
public void logResponseHead(HttpURLConnection con) 1FtM>&%4  
{ uxg9yp@|  
for(int i=1;;i++) Le"oAA#[  
{ syip;;  
String header=con.getHeaderFieldKey(i); lnE+Au'  
if(header!=null) ]|_\x
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); yqSs,vz  
Utility.log(header+" : "+con.getHeaderField(header)); GE|+fYVM-$  
else zrVC8Wb  
break; s4_/&h  
} fQLt=Lrp  
} ,@m@S^  
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public void splitterStop() kt4d;4n  
{ fF*`'i=!  
bStop = true; =h(W4scgqX  
} h;5LgAY|v  
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} MxzLK%am  
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/* ~j#~\Ir  
**FileAccess.java V|)>{Xdn  
*//文件访问(定位，写) VL9-NfeqR  
package NetFox; $8l({:*q0  
import java.io.*; Wlh~)  
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public class FileAccessI implements Serializable{ !L5jj#0  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Lp5U"6y  
RandomAccessFile oSavedFile; PX|=(:(k  
long nPos; XWJwJ  
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public FileAccessI() throws IOException %LXM+<N8  
{ "o& E2#  
this("",0); (wc03,K^  
} ]CU]pK?nq  
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public FileAccessI(String sName,long nPos) throws IOException )'l*Tl  
{ A?G IBjs  
oSavedFile = new RandomAccessFile(sName,"rw"); m~Ld~I"  
this.nPos = nPos; Z%Z9oJ:  
oSavedFile.seek(nPos); Gamr6I"K  
} M.h`&8  
6)pH|d.FR  
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public synchronized int write(byte[] b,int nStart,int nLen) reo{*)%  
{ C1T_9}L-A  
int n = -1; c62=*] ,  
try{ HaA1z}?n  
oSavedFile.write(b,nStart,nLen); _w@qr\4i=  
n = nLen; "QoQ4r<|  
} P#v*TD'  
catch(IOException e) SPj><5Ro  
{ B*!W
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e.printStackTrace (); 4YZS"K'E  
} zb6ju
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return n; P
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} 1 4LI5T  
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} L]a`"CH:a$  
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/* U=bEA1*@0  
**SiteInfoBean.java eUS  
*/ 'H9=J*9oG  
package NetFox; Bs`$i ;&  
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public class SiteInfoBean { NGYyn`Lx  
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private String sSiteURL; //Site's URL wx=0'T-[  
private String sFilePath; //Saved File's Path =1dI>M>tm  
private String sFileName; //Saved File's Name ^s\3/z>b4!  
private int nSplitter; //Count of Splited Downloading File ^"8G`B$r  
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public SiteInfoBean() OEd
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{//nSplitter的缺省值为5 }~Q"s2  
//default value of nSplitter is 5 h72UwJ2rw  
this("","","",5); 4VN aq<8  
} Z?i /r5F  
}aB#z<B6  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0f ER*.F  
{ 'NZGQebK  
sSiteURL= sURL; h%d^Gq~  
sFilePath = sPath; i5hD
#  
sFileName = sName; c*\<,n_  
this.nSplitter = nSpiltter; b7C e%Br  
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"rXOsX\;  
} ;??ohA"{5  
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public String getSSiteURL() :

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{ ~Pk0u{,4XQ  
return sSiteURL; 6FfOH<\z6i  
} }:iBx  
NTs;FX~g[  
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public void setSSiteURL(String value) Al)$An-  
{ TOl}U  
sSiteURL = value; YHxbDf dA  
} x:K?\<  
>L((2wfiN  
cu#e38M&eE  
public String getSFilePath() ]/]ju$l9Z  
{ ,S[K{y<
 
return sFilePath; )"@t6.  
} y_F}s9wj  
?4PQQd  
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public void setSFilePath(String value) +2cs
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{ bggusK<  
sFilePath = value; WoL9V"]  
} B_3QQtjAl  
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public String getSFileName()
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{ ,W5.:0Y;f[  
return sFileName; ?s} %  
} t> Q{yw  
x49!{}  
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public void setSFileName(String value) bk#xiuwT  
{ f
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sFileName = value; Rc
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} T)u4S[ &  
s(@h 2:j  
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public int getNSplitter() y<r}"TAf-  
{ Uku5wPS  
return nSplitter; 2@@l{Y0f6  
} jThbeY[  
_&{%Wc5W~F  
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public void setNSplitter(int nCount) tR
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{ .{dE}2^  
nSplitter = nCount; -R+zeu(e'  
} ;'kI/(;;C  
} T@+ClZi  
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/* u?Hb(xZtg=  
**Utility.java MB$a82bY  
*/ a#(U2OP  
package NetFox; =TcOnQj  
:uCdq`SaQl  
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public class Utility { tbj=~xYf  
Z}Cqd?_')  
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public Utility() ~@c-*  
{ g,
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k'13f,o}  
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} TL-i=\{L:d  
}0eg{{g8  
//线程睡眠 =t+('  
public static void sleep(int nSecond) _x\m|SF_g  
{ qb7^VIo%c  
try{ }5S2p@W)  
Thread.sleep(nSecond); Dt}dp_  
} F?*k}]Gi  
catch(Exception e) G\rj?%  
{ r
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e.printStackTrace (); ;w6s<a@Zh  
} d.}}s$Q  
} jn=ug42d  
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//日志 -{x(`9H;  
public static void log(String sMsg) S=9E@(]  
{ b~wKF0vq  
System.err.println(sMsg); #tz8{o?ebN  
} H`|0-`q  
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public static void log(int sMsg) "@t-Cy:!O  
{ $[e%&h@JR  
System.err.println(sMsg); N du7nKG  
} [\HQPo'S  
} &c^7O#j  
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/* Y?!/>q  
**TestMethod.java wXCyj+XB*  
*/ {visv{R<  
package NetFox; }u
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public class TestMethod { Z[;#|$J  
>\\5"Sf  
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public TestMethod() TNsg pJ?\  
{ ///xx/weblogic60b2_win.exe b+$o4l/x  
try{ Ec.)!Hu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qRUCnCZs  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); eiB(VOJ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Q<'@V@H  
fileFetch.start(); 32KR--mn%  
} 9S"N4c>  
catch(Exception e){e.printStackTrace ();} Gc}0]!nrW9  
![H
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7K !GK  
} lm &^tjx  
+3?`M<L0  
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public static void main(String[] args) ;y>'yq}  
{ Jk~UEqr+  
new TestMethod(); >Jiij  
} jaa/k@OG  
} 8l?w=)Qy  
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