http断点续传简单实现（java)

/* PZ,z15PG]  
**SiteFileFetch.java Hm9<fQuM  
*/ |nY~ZVTt/  
package NetFox; &U"X$aFc  
import java.io.*; Np2ci~"<
.  
import java.net.*; )X5(#E  
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public class SiteFileFetch extends Thread { n
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SiteInfoBean siteInfoBean = null; //文件信息Bean Zw$ OKU  
long[] nStartPos; //开始位置 f=`33m5  
long[] nEndPos; //结束位置 SRL-Z&M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 v
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long nFileLength; //文件长度 `,Orf ZMb  
boolean bFirst = true; //是否第一次取文件 _k2w(ew?  
boolean bStop = false; //停止标志 >85zQ 1aL  
File tmpFile; //文件下载的临时信息 ?QpNjsF  
DataOutputStream output; //输出到文件的输出流 S~3\3qt$  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;&f1vi4  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1R*=.i%W  
{ %8FN0  
siteInfoBean = bean; q`Q}yE>9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y~qb;N\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); E4HU 'y~  
if(tmpFile.exists ()) &q>zR6jne  
{ |LmSWy*7  
bFirst = false; ^8K/xo-  
read_nPos(); H+l,)Se  
}  t;47(U  
else #C*&R>IvY  
{ C_->u4-  
nStartPos = new long[bean.getNSplitter()]; S%l:kKD  
nEndPos = new long[bean.getNSplitter()]; R1%y]]*-P  
} >ttuum12w  
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n%$ &=-Fk  
} [ee30ELn  
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public void run() z~Na-N  
{ FtIa*j^G  
//获得文件长度 p2d\ZgWD=)  
//分割文件 '*R%^RK  
//实例FileSplitterFetch 4%_M27bu[  
//启动FileSplitterFetch线程 R^8{bP  
//等待子线程返回 X9XI;c;b-
 
try{ [,g~m9  
if(bFirst) sN/+   
{ l
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nFileLength = getFileSize(); `# ^0cW  
if(nFileLength == -1) QxpKX_@Q5  
{ YYUe)j{T  
System.err.println("File Length is not known!"); gx;O6S{  
} )^/0cQcJ  
else if(nFileLength == -2) PW)aLycPK  
{ =~|:t&v=c  
System.err.println("File is not access!"); x-_vl 9P)  
} cm@;*  
else %l$W*.j|;  
{ 91d },Mq:  
for(int i=0;i<nStartPos.length;i++) p;%<mUI  
{ :
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nStartPos = (long)(i*(nFileLength/nStartPos.length));  CL3xg)x6  
} kGHC]Fb)  
for(int i=0;i<nEndPos.length-1;i++) |_zO_Frtp  
{ 5 9-!6;T  
nEndPos = nStartPos[i+1]; O#_x)13  
} :&yDqoQKJ  
nEndPos[nEndPos.length-1] = nFileLength; ^:cRp9l"7  
} P))^vUt~  
} FFzH!=7T?  
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//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; M{KW@7j  
for(int i=0;i<nStartPos.length;i++) flnVYQe  
{ r@$ w*%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8cdsToF(e.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (:sZ b?*  
nStartPos,nEndPos,i); U Cb02h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b^Cfhy^RTq  
fileSplitterFetch.start(); OhwF )p=  
} O@&+} D>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5H !y46z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Tr.hmGU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5D' bJ6PO  
nEndPos = " + nFileLength); 4#BRx#\O  
// fileSplitterFetch[nPos.length-1].start(); m<@z}%v-  
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//等待子线程结束 5*G%IR@@LK  
//int count = 0; Qv{,wytyO  
//是否结束while循环 >*qQ+_  
boolean breakWhile = false; "J19*<~  
, =y#m-9  
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while(!bStop) x';uCKWV  
{ CL9yEy"V  
write_nPos(); 5PiOH"!19  
Utility.sleep(500); W{Z^n(f4  
breakWhile = true; C`K^L=8`{  
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for(int i=0;i<nStartPos.length;i++) 7%d8D>uw8  
{ BIMKsF Zt  
if(!fileSplitterFetch.bDownOver) h9CIZU[Nh  
{ +^ yq;z  
breakWhile = false; f j<H6|3  
break; VmvQvQ/9R  
} bToq$%sCg  
} wCb(>
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if(breakWhile) $a#H,Xv#  
break; 658^"]Rk'/  
@x{`\AM|%  
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//count++; G0d&@okbFC  
//if(count>4) ?F@%S3h.  
// siteStop(); ' Q7Y-V  
} 8Y{s;U0n  
9-lEtl%  

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System.err.println("文件下载结束！"); $8=@R'  
} wk$,k  
catch(Exception e){e.printStackTrace ();} `f`TS#V  
} 2Q
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//获得文件长度 82:W
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public long getFileSize() x` /)g(  
{ "/+zMLY  
int nFileLength = -1; Qn+:/zA;  
try{ s~L</Xvo  
URL url = new URL(siteInfoBean.getSSiteURL()); 7P**:b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qc"'8kt  
httpConnection.setRequestProperty("User-Agent","NetFox"); D"l+iVbBP  
8q^o.+9  
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int responseCode=httpConnection.getResponseCode(); sqO<J$tz  
if(responseCode>=400) 7"2b H  
{ +4)7j&L  
processErrorCode(responseCode); p EusTP  
return -2; //-2 represent access is error qx)?buAij  
} X?Pl<l&  
9F##F-
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String sHeader; )D@~|j:  
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for(int i=1;;i++) m $dV<  
{ !m
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kfrY1  
//Utility.log(in.readLine()); elO<a]hX  
sHeader=httpConnection.getHeaderFieldKey(i); M\2"gT-LV  
if(sHeader!=null) WxUxc75  
{ bbN%$/d  
if(sHeader.equals("Content-Length")) 77,oPLSn  
{ +c$I&JO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #@f[bP}a  
break; raUs%Y3  
} eV!L^>>>  
} B6M+mx"G  
else e XV@.  
break; \k@$~}xD,  
} *75YGD  
} Z~u9VYi!  
catch(IOException e){e.printStackTrace ();} uO(w1Q"^  
catch(Exception e){e.printStackTrace ();} $:bih4@>  
a)s;dp}T%  
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Utility.log(nFileLength); eph)=F$  
1|| nR4yK  
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return nFileLength; m5c&&v6%"b  
} pbBoy+.>  
+
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/b[2lTC-e  
//保存下载信息（文件指针位置） !{UTD+|=N  
private void write_nPos() *b|NjwmB  
{ AHbZQulC  
try{ ~}ovuf=%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); m,MSMw1p  
output.writeInt(nStartPos.length); lxb zHlX  
for(int i=0;i<nStartPos.length;i++) I9
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{ fg*@<'  
// output.writeLong(nPos); LJTo\^*  
output.writeLong(fileSplitterFetch.nStartPos); 2YBIWR8z  
output.writeLong(fileSplitterFetch.nEndPos); '\7G@g?UZ  
} NC"yDWnO'  
output.close(); rpV1y$n<F  
} QWO]`q`|  
catch(IOException e){e.printStackTrace ();} L^J-("e_  
catch(Exception e){e.printStackTrace ();} 1,t)3;o$  
} _M5%V>HO  
R= 5**  
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//读取保存的下载信息（文件指针位置） n! h7
 
private void read_nPos() yi6N-7  
{ h0|}TV^UJ  
try{ 2KJ1V+g@a6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O[q\e<V<  
int nCount = input.readInt(); 8*a), 3aK  
nStartPos = new long[nCount]; VD7i52xS  
nEndPos = new long[nCount]; 9^ed-h Bf  
for(int i=0;i<nStartPos.length;i++)
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{ 7}o/:  
nStartPos = input.readLong(); yW7'?  
nEndPos = input.readLong(); hf<J \   
} =?Fkn4t  
input.close(); nD6G  
} 7(k^a)~PL  
catch(IOException e){e.printStackTrace ();} ?A*Kg;IU  
catch(Exception e){e.printStackTrace ();} S33j?+
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} WrGK
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private void processErrorCode(int nErrorCode) 4vZ4/#(x  
{ |L3X_Me  
System.err.println("Error Code : " + nErrorCode); M4f;/`w  
} .K8w8X/3  
ii|?;  
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//停止文件下载 G-um`/<%  
public void siteStop() y0bq;(~X~  
{ _k66Mkd#b  
bStop = true; ':h =*v8a  
for(int i=0;i<nStartPos.length;i++) o+O}Te  
fileSplitterFetch.splitterStop(); 2?7(A  
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} A$/\1282  
} ,ZE?{G{tuj  
//负责部分文件的抓取 S7iDTG_@t  
**FileSplitterFetch.java C}}/)BYi  
*/ k%'m*Tf  
package NetFox; 3\$wdUFr  
2B1xUj ]  
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import java.io.*; 48D?'lW %  
import java.net.*; 7N8H)X
 
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public class FileSplitterFetch extends Thread { .giz=*q+  
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String sURL; //File URL ?}p:J{  
long nStartPos; //File Snippet Start Position |+,[``d>"  
long nEndPos; //File Snippet End Position pf"<!O[  
int nThreadID; //Thread's ID AG6K daJ  
boolean bDownOver = false; //Downing is over (K..k-o`.  
boolean bStop = false; //Stop identical E)N<lh  
FileAccessI fileAccessI = null; //File Access interface 8AFczeg[[  
I s57F4[}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  \[:/CxP  
{ m}j
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this.sURL = sURL; dR^"X3$  
this.nStartPos = nStart; I~* ? d  
this.nEndPos = nEnd; (<*e  
nThreadID = id; R=j% S!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BHFY%6J!  
} f2I6!_C!+  
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public void run() cQj-+Tmu  
{ +/{L#e>  
while(nStartPos < nEndPos && !bStop) hcCp,b  
{ 6i@\5}m=  

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try{ @p=
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URL url = new URL(sURL); ShOX<Fb&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 25y6a|`  
httpConnection.setRequestProperty("User-Agent","NetFox"); Mz]:}qmFA  
String sProperty = "bytes="+nStartPos+"-"; 5sO@OV\ y  
httpConnection.setRequestProperty("RANGE",sProperty); `YBkF  
Utility.log(sProperty); Y4.Eq+$gh  
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InputStream input = httpConnection.getInputStream(); H].y w9  
//logResponseHead(httpConnection); Lv[OUW#S  
266oTER]v:  
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byte[] b = new byte[1024]; ./6<r OW  
int nRead; 0C%W&;r0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) AV8T  
{ 6vKS".4C  
nStartPos += fileAccessI.write(b,0,nRead); una%[jTc  
//if(nThreadID == 1) nKr9#JebRC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K4Dp:2/K%  
} |]=2 }%1w  
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Utility.log("Thread " + nThreadID + " is over!"); SO\/-]9#  
bDownOver = true; Q^Ql
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//nPos = fileAccessI.write (b,0,nRead); _,74)l1  
} ">81J5qgd  
catch(Exception e){e.printStackTrace ();} FyoEQ%.bI  
} tvKAIwe  
} T GB_~Bqe  
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"t=hzn"~%  
//打印回应的头信息 Joe_PS  
public void logResponseHead(HttpURLConnection con) SlLw{Yb7\.  
{ R8ONcG  
for(int i=1;;i++) oPKr* `'  
{ K0+.q?8D|  
String header=con.getHeaderFieldKey(i); owpWz6k7  
if(header!=null) 
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); NSAF4e  
Utility.log(header+" : "+con.getHeaderField(header)); y&[y=0!  
else |!SOG  
break; LA3<=R]  
} )D-c]+yt  
}  _?voU  
J T#d(Y  
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public void splitterStop() M6r^L6$N  
{ LK9g0_  
bStop = true; $4FX(O0Q@  
} 8e~|.wOL  
s MN*RKer  
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} V! |qYM.  
)}%O>%  
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/* ^E`(*J/o  
**FileAccess.java <N,)G |&  
*//文件访问(定位，写) DHC+C4  
package NetFox; f
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import java.io.*; H1"q  
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public class FileAccessI implements Serializable{ @Y,7'0U  
hJz):d>Im  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 dx*qb  
RandomAccessFile oSavedFile; YNrp}KQ  
long nPos; J/!cGr(B~  
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public FileAccessI() throws IOException 'uDjFQX  
{ J~B 7PW  
this("",0); _lKZmhi  
} )&{K~i;:  
8x{B~_~  
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public FileAccessI(String sName,long nPos) throws IOException Fk;oE'"D  
{ {+<P:jbz;  
oSavedFile = new RandomAccessFile(sName,"rw"); 2g9G{~,@g  
this.nPos = nPos; # {fTgq  
oSavedFile.seek(nPos); H=g.34  
} L%}zVCg  
; |/leu8  

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public synchronized int write(byte[] b,int nStart,int nLen) u,3,ck!B>@  
{ l%z<(L5  
int n = -1; *Oc.9 F88"  
try{ 4n1; Bh$  
oSavedFile.write(b,nStart,nLen); %owsBO+  
n = nLen; 9~rUkHD  
} Z|9
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catch(IOException e) '\fY<Q:!  
{ ./j,
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e.printStackTrace (); Y!q!5Crfi  
} -V"22sR]  
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return n; "N:XzG  
} lJP1XzN_  
@;xMs8@  
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} +`M!D }!  
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f=!PllxL:  
/* CxhY$%C (L  
**SiteInfoBean.java d8SE,A&  
*/ m\>a,oZH  
package NetFox; rKHY?{!  
Fhz*&JC#  
l:6,QaT1  
public class SiteInfoBean { ffXyc2o  
}u+a<:pkK  
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private String sSiteURL; //Site's URL m]_FQWfet  
private String sFilePath; //Saved File's Path qQi.?<d2"s  
private String sFileName; //Saved File's Name thO ~=
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private int nSplitter; //Count of Splited Downloading File Ko&hj XHx  
.I VlEG0  
3bqC\i^[\m  
public SiteInfoBean() m+{K^kr[  
{//nSplitter的缺省值为5 WD;Y~|  
//default value of nSplitter is 5 z|7z
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this("","","",5); ~m1P_`T  
} bk<\ujH  
Sx:Ur>?hd5  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1Kvx1p   
{ 3QSZ ZJ  
sSiteURL= sURL; xt'tL:d  
sFilePath = sPath; .,~(%#Wl$  
sFileName = sName; A`}yBSb  
this.nSplitter = nSpiltter; 3Y)PU=  
S0g'r !;6  
@ DZD  
} =z{JgD/  
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ri C[lB  
public String getSSiteURL() N4;7gSc"  
{ ]Mj/&b>"e  
return sSiteURL; Sp}D;7  
} biozZ  
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GEjd7s]C  
public void setSSiteURL(String value) VKm!Ri$  
{ FVv8--  
sSiteURL = value; !|2VWI}  
} .t&R>9cZ^  
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public String getSFilePath() Tj~IaU  
{ 1[*UYcD  
return sFilePath; *'"T$i
b  
} H4OhIxK  
Bb&^{7  
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public void setSFilePath(String value) ,U*)2`[  
{ a</D_66  
sFilePath = value; ?Y:x[pOe  
} ;)Kh;;e  
&`Y!;@K9W#  
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public String getSFileName() PqNFyQkl  
{ H7+X&#s%  
return sFileName; E^_wI>  
} {Z;jhR,  
x#~ x;)  
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public void setSFileName(String value) 41#w|L \  
{ %or,{mmiM:  
sFileName = value; \JG8KE=j  
} <";,GaZQ  
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=k3!RW'  
public int getNSplitter() %2'A pp  
{ S1n3(U:m  
return nSplitter; |o'Q62`%}  
} KPSh#x&I  
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public void setNSplitter(int nCount) &"_u}I&\  
{ ERUt'1F?]  
nSplitter = nCount; WWwUwUi  
} oRN-xng  
} 3`O?16O  
s#h8%['  
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/* |CgnCUv+  
**Utility.java {^{p,9  
*/
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package NetFox; jk\ dG16  
:
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public class Utility { c~
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"HD+rmUEH  
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public Utility() "Th$#3  
{ _FbC{yI8;  
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} s"=6{EVqk3  
2y0J`!/)  
//线程睡眠 k)S.]!u&G  
public static void sleep(int nSecond) tg4Y i|5  
{ zWw2
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try{ Kzy/9  
Thread.sleep(nSecond); BhpOXqg  
} 6Dws,_UAZ4  
catch(Exception e) 0YH+B
 
{ tC8(XMVx  
e.printStackTrace (); C8@TZ[w  
} ZA~Z1Mro#"  
} v,NHQyk  
Uu6L~iB  
//日志 CZ2`H[8  
public static void log(String sMsg) M"q[p  
{ "%WgT2)m.  
System.err.println(sMsg); (VyNvB  
} v8>v.}y  
->-*]-fv[L  
Ot&:mT!2  
public static void log(int sMsg) YF#HSf7  
{ F0~k1TDw  
System.err.println(sMsg); g1(Xg.  
} JGiKBm;  
} +ww^ev%  
||2Q~*:  
hf!|\f  
/* qv 3^5d  
**TestMethod.java <Y 4:'L6  
*/ >-T`0wI  
package NetFox; N;F)jO xsl  
iMF<5fLH&  
'f8(#n=6qP  
public class TestMethod { >YW\~T  
Auy".br'  
'2J0>Bla  
public TestMethod() 7>o.0  
{ ///xx/weblogic60b2_win.exe y#ON|c /  
try{ pl*~kG=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); rgIrr5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); z `8cOK
-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~>G]_H]?  
fileFetch.start(); `U!y
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} GYRYbiwqdi  
catch(Exception e){e.printStackTrace ();} O@8pC+#`Z  
W:&R~R  
k!jNOqbb  
} J.*XXM- V  
%/"Oxi^G  
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public static void main(String[] args) qOCJTOg7  
{ Q>}2cDl  
new TestMethod(); v=YK8fNi  
} 1F[L"W;r  
} bTmL5}n  
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