http断点续传简单实现（java)

/* P?
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**SiteFileFetch.java IO=$+c  
*/ 6\I1J= C  
package NetFox; IhZn  
import java.io.*; UQ7]hX9  
import java.net.*; p9u'nDi  
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public class SiteFileFetch extends Thread { ^?sP[;8S!  
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SiteInfoBean siteInfoBean = null; //文件信息Bean EStui>ho  
long[] nStartPos; //开始位置 (y&sUc9  
long[] nEndPos; //结束位置 d6JW"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~t
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long nFileLength; //文件长度 >$-YNZA   
boolean bFirst = true; //是否第一次取文件 -\;0gnf{J  
boolean bStop = false; //停止标志 4pQf*l8e  
File tmpFile; //文件下载的临时信息 $\/^O94-l  
DataOutputStream output; //输出到文件的输出流 :b %2qBv  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） w$-q&  
public SiteFileFetch(SiteInfoBean bean) throws IOException i|AWaG)  
{ 1jop;{,^  
siteInfoBean = bean; G8%VL^;O*5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ){'<67dK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _(8#  
if(tmpFile.exists ()) B&B:P  
{ gt(p%~  
bFirst = false; >JsVIfAF
 
read_nPos(); ITqAy1m@
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} dhnX\/  
else y {Bajil  
{ `O0Qtq.  
nStartPos = new long[bean.getNSplitter()]; )`'a1y|  
nEndPos = new long[bean.getNSplitter()]; 4uMMf  
} cb0rkmO  
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} (?^F }]  
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public void run() x7<l*WQ  
{ phf{b+'#X  
//获得文件长度 |? fAe{*  
//分割文件 c_+fA  
//实例FileSplitterFetch (}>)X]  
//启动FileSplitterFetch线程 quaRVD>s +  
//等待子线程返回 glU9A39qx?  
try{ H'/V<
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if(bFirst) Al8Dw)uG{  
{ ![r)KE=v8I  
nFileLength = getFileSize(); $b{8$<;9  
if(nFileLength == -1) ;}U]^LT=  
{ lemV&$WN|  
System.err.println("File Length is not known!"); >yP>]r+  
} 5EI"5&`*  
else if(nFileLength == -2) N}7b^0k  
{ =A'JIssk  
System.err.println("File is not access!"); MmvOyKNZF  
} DBcR1c&<H  
else =LK`mNA  
{ kv2o.q  
for(int i=0;i<nStartPos.length;i++) SnXM`v,  
{ `RE>gX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); GeB&S!F  
} z(^dwMw}  
for(int i=0;i<nEndPos.length-1;i++) 4fjwC,,  
{ 'U0W  
nEndPos = nStartPos[i+1]; DL!%Np?`  
} 9tVV?Q@)  
nEndPos[nEndPos.length-1] = nFileLength; 8]R{5RGy  
} W}MN-0  
} BNI)y@E^X  
p?4[nS-,  
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//启动子线程 S9r+Nsn  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4neO$^i8J  
for(int i=0;i<nStartPos.length;i++) Qf}.=(  
{ RgQs`aI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P+OS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), woBx609Aak  
nStartPos,nEndPos,i); 5/7(>ivn  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lI.oyR'  
fileSplitterFetch.start(); FoH1O+e  
} cY kb3(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~a&VsC#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (K84J*;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h0g?=hJq  
nEndPos = " + nFileLength); 4K? \5(b  
// fileSplitterFetch[nPos.length-1].start(); dt+r P%  
gt02Csdt  
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//等待子线程结束 6yMZ2%  
//int count = 0; !U1 vW}H  
//是否结束while循环 U"+W)rUd  
boolean breakWhile = false; IOdxMzF`m  
@DY"~ccH  
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while(!bStop) ZILJXX4  
{ !Hl]&  
write_nPos(); DZnqCu"J  
Utility.sleep(500); |('o g*
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breakWhile = true; 2.b,8wT/  
tH.L_< N  
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for(int i=0;i<nStartPos.length;i++) .SER,],P  
{ g3>>gu#0DC  
if(!fileSplitterFetch.bDownOver) 3Ke6lV)uq  
{ z8JW iRn  
breakWhile = false; ,I x>.^|  
break; F4==a
8  
} Dm5 Uy^F}  
} bp=r]nO  
if(breakWhile) !U m9ceK  
break; h@G~'\8t  
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//count++; Z_m<x!  
//if(count>4) PgT8 1u  
// siteStop(); ?
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} 4^bt~{}  
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System.err.println("文件下载结束！");  #O\as~-  
} |.0~'  
catch(Exception e){e.printStackTrace ();} UgS`{&
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} pa+'0Y]71  
@=dv[P"jn  
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//获得文件长度 nk%v|ZxoFv  
public long getFileSize()  ,S=[#  
{ dVEs^ZtI  
int nFileLength = -1; __.MS6"N  
try{ k/
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URL url = new URL(siteInfoBean.getSSiteURL()); . c+m(Pk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \j62"

  
httpConnection.setRequestProperty("User-Agent","NetFox"); *0!p_Hco  
[=q/f2_1.  
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int responseCode=httpConnection.getResponseCode(); `HXv_9  
if(responseCode>=400) A%W]XEa<  
{ l X+~;94  
processErrorCode(responseCode); S1U0sP@o  
return -2; //-2 represent access is error ^py=]7[I  
} >U{iof<  
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String sHeader; }]o8}$&(  
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for(int i=1;;i++) K_)~&Cu*'  
{ ?o;ip  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); xj>P5\mW#  
//Utility.log(in.readLine()); 6-
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sHeader=httpConnection.getHeaderFieldKey(i); (6ga*5<  
if(sHeader!=null) >80k5$t  
{ `z(o01y  
if(sHeader.equals("Content-Length")) 3LLG#l)8  
{ x:MwM?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /GO-  
break; nD BWm`kN  
} N<rq}^qo  
} rzAf {2  
else @Z ==B%`  
break; *HR pbe2  
} -a)1L'R  
} FprdP*/  
catch(IOException e){e.printStackTrace ();} zK5&,/  
catch(Exception e){e.printStackTrace ();} HRyFjAR\?  
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Utility.log(nFileLength); Ow/,pC >V  
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return nFileLength;  \nEMj,)  
} ?4R%z([X7  
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; R+>}6  
//保存下载信息（文件指针位置） Pb'
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private void write_nPos() S<i1t[E@W  
{ T5u71C_wmt  
try{ P_A@`eU0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Pj

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output.writeInt(nStartPos.length); ]oV{JR]  
for(int i=0;i<nStartPos.length;i++) Nf)YG!  
{ vd ls
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// output.writeLong(nPos); %cSx`^`6j  
output.writeLong(fileSplitterFetch.nStartPos); fG'~@'P~  
output.writeLong(fileSplitterFetch.nEndPos); `Jc/ o=]  
}
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output.close();
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} F `o9GLxM}  
catch(IOException e){e.printStackTrace ();} <rE>?zvm  
catch(Exception e){e.printStackTrace ();} P5?VrZy  
} z+yq%O  
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//读取保存的下载信息（文件指针位置） !Sn|!:N4  
private void read_nPos() T9V=#+8#"  
{ y-3'qq'E  
try{ $b|LZE\bU.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); vT EqT  
int nCount = input.readInt(); 9PKXQp  
nStartPos = new long[nCount]; R)66qRf  
nEndPos = new long[nCount]; @
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for(int i=0;i<nStartPos.length;i++) =T9h7c R  
{ ?\8aT"o  
nStartPos = input.readLong(); c7r(&h  
nEndPos = input.readLong(); j_2g*lQ7a  
} `*vO8v  
input.close(); Ts !g=
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} XA!a^@<H  
catch(IOException e){e.printStackTrace ();} Hq}g1?b  
catch(Exception e){e.printStackTrace ();} {KHI(*r;  
} A6=Z2i0w>X  
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private void processErrorCode(int nErrorCode) C!^A\T7p  
{ ch8VJ^%Ra1  
System.err.println("Error Code : " + nErrorCode); "j_iq"J  
} DYf2V6'  
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<CVX[R]U  
//停止文件下载 O6Py  
public void siteStop() h&j2mv(  
{ e=(Y,e3  
bStop = true; oUnb-,8n  
for(int i=0;i<nStartPos.length;i++) AF#:*<Ev  
fileSplitterFetch.splitterStop(); nCi ]6;Y  
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} i[KXkjr  
} )(G<(eiD  
//负责部分文件的抓取 r:V bjmL  
**FileSplitterFetch.java H7+z"^s*  
*/ ywp_,j9F  
package NetFox; F\N0<o  
>;Hx<FKxP  
?-c|c_|$  
import java.io.*; bQ>wyA+G&E  
import java.net.*; D 1.59mHsD  
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public class FileSplitterFetch extends Thread { -E\G3/*51  
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String sURL; //File URL cV>?*9z0  
long nStartPos; //File Snippet Start Position T2rwK2  
long nEndPos; //File Snippet End Position S=P}Jpq?Y;  
int nThreadID; //Thread's ID vx?KenO}  
boolean bDownOver = false; //Downing is over o+hp#e  
boolean bStop = false; //Stop identical E&J<qTH9  
FileAccessI fileAccessI = null; //File Access interface ;cf$u}+  
#"6l+}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B)7:*Kj  
{ ?x",VA  
this.sURL = sURL; FMCA~N  
this.nStartPos = nStart; 7a9">:~  
this.nEndPos = nEnd; VJ-t#q"  
nThreadID = id; ,2!7iX  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -}TP)/!,*  
} 1^o})9  
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public void run() &kdW(;`  
{ Uot(3p!S6  
while(nStartPos < nEndPos && !bStop) -ioO8D&!  
{ ):G+*3yb  
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try{ =UO7!vr;[  
URL url = new URL(sURL); SLP$|E;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N@0/
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httpConnection.setRequestProperty("User-Agent","NetFox"); #pRbRT9  
String sProperty = "bytes="+nStartPos+"-"; |7|'JTy  
httpConnection.setRequestProperty("RANGE",sProperty); &56\@t^  
Utility.log(sProperty); =S54p(>  
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InputStream input = httpConnection.getInputStream(); 8B6(SQp%  
//logResponseHead(httpConnection); -"Kjn`8  
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byte[] b = new byte[1024]; D_F1<q  
int nRead; uAYDX<Ja9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @?tR-L<u  
{ F'<XB~&o  
nStartPos += fileAccessI.write(b,0,nRead); r8y,$Mv<)0  
//if(nThreadID == 1) y1Br4K5C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C.=%8|Zy  
} }cW8B"_"  
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Utility.log("Thread " + nThreadID + " is over!"); (8S+-k?  
bDownOver = true; T;k
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//nPos = fileAccessI.write (b,0,nRead); qoQ,3&<  
} !+hw8@A  
catch(Exception e){e.printStackTrace ();} 29@m:=-}7  
} :gkn`z  
} *Q-uE  
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//打印回应的头信息 JDpW7OrDc  
public void logResponseHead(HttpURLConnection con) 5?#AS#TD'  
{ tPJU,e)  
for(int i=1;;i++) Kv5 !cll5  
{ coXm*X>z  
String header=con.getHeaderFieldKey(i); d8jP@
>  
if(header!=null) }z-)!8vF  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &fxyY(  
Utility.log(header+" : "+con.getHeaderField(header)); &~)1mnv.  
else a,t]>z95  
break; KH$o X\v  
} Xs4G#QsAJ  
} vf<Tq  
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public void splitterStop() @:u2{>Yl  
{ s\ ]Rgi>w  
bStop = true; Wf  *b"#  
} rYA4(rYq  
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} `ucr;P  
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u $T'#p1  
/* /I#SP/M&l  
**FileAccess.java z:tu_5w!,  
*//文件访问(定位，写) 0>?78QL9<  
package NetFox; X?]1/6rV  
import java.io.*; 8!dA1]2;  
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/&'rQ`nd  
public class FileAccessI implements Serializable{ L sMS`o6  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 XS"lR |  
RandomAccessFile oSavedFile; R*psL&N  
long nPos; 8|p*T&Cn&  
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public FileAccessI() throws IOException -J*jW N!  
{ Z:}d\~`x$%  
this("",0); Obu>xK(  
} gG.b=DvzY  
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public FileAccessI(String sName,long nPos) throws IOException IGd]!  
{ MRdZ'  
oSavedFile = new RandomAccessFile(sName,"rw"); jDO[u!J6.%  
this.nPos = nPos; $fA%_T_P'P  
oSavedFile.seek(nPos); vHPp$lql  
}
~vIQ-|8r:  
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public synchronized int write(byte[] b,int nStart,int nLen) Jtxwt[  
{ Yvu!Q  
int n = -1; Zi fAn  
try{ 4b B)t#  
oSavedFile.write(b,nStart,nLen); 4c*?9r@  
n = nLen; A~6:eappH  
} dk9'C  
catch(IOException e) 4~3 N;]X  
{ x2\,n  
e.printStackTrace (); j ,'$i[F'  
} B#_<?  
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return n; {f\/2k3  
} l* =\0
  
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} awU!3)B  
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/* /$\N_`bM  
**SiteInfoBean.java 9oj#5Hq  
*/ M!`&Z9N  
package NetFox; 2^X<n{0N)  
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public class SiteInfoBean { |4C5;"Pc  
+Pc2`,pw|  
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private String sSiteURL; //Site's URL )%JjV(:  
private String sFilePath; //Saved File's Path 8kf5u#,'  
private String sFileName; //Saved File's Name eemC;JV%  
private int nSplitter; //Count of Splited Downloading File 5yL\@7u`  
< ZG!w^  
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public SiteInfoBean() ,7I    
{//nSplitter的缺省值为5 _<6E>"*m  
//default value of nSplitter is 5 Yc:>Yzj(z  
this("","","",5); [Mk:Zz%  
} Bdcs}Ga  
,`ba?O?*G  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {(IHHA>  
{ `i vE:3k  
sSiteURL= sURL; q:1n=iEi  
sFilePath = sPath; 12V-EG i  
sFileName = sName; \Ez&?yb/  
this.nSplitter = nSpiltter; uO((Mg  
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*qJHoP;  
} b w!  
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public String getSSiteURL() 6"9(ce KX  
{ gL&)l!2Y  
return sSiteURL; Jim5Ul  
} t9.| i H  
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public void setSSiteURL(String value) :7*9W|e  
{ Ekn3ODz,  
sSiteURL = value; "[sr0'g:  
} mYqLqezAA  
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public String getSFilePath() Z-L}"~  
{ !ZM*)
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return sFilePath; 09=w  
} `NyO|9/4
 
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public void setSFilePath(String value) >x]ir  
{ (_Th4'(@Y  
sFilePath = value; {Q)sR*d  
} jw)c|%r>  
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a
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public String getSFileName() NAO0b5-h  
{ 4YXp,U  
return sFileName; hP_{$c{4:g  
} #
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public void setSFileName(String value) d>0 j!+s  
{ w6ck wn,  
sFileName = value; A~;.9{6J[t  
} PB#EU9  
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@vO~'Xxq!  
public int getNSplitter() m
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{ ;,Os3  
return nSplitter; ^[EXTBk@:  
} (hIe!"s*  
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public void setNSplitter(int nCount) ")u)AQ  
{ FX+^S?x.  
nSplitter = nCount; {~V_6wY g  
} PI)uBA;  
} C9j5Pd5q1L  
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/* UdFYG^i  
**Utility.java ~Q)Dcit-  
*/ 1#x@  
package NetFox; RPkOtRKL=w  
5 HN,y  
6W'2w?qj?4  
public class Utility { ah!fQLMH  
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public Utility() +}C M2>M  
{ wEEFpn_   
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} Jh%k:TrBm  
c#pVN](?  
//线程睡眠 7T?7KS  
public static void sleep(int nSecond) .-:6L2  
{ 9-?kamA  
try{ 6K5KkEp  
Thread.sleep(nSecond); Of{'A  
} @_?8I_\:  
catch(Exception e) a;0$fRy  
{ cx4'rK.  
e.printStackTrace (); "HbrYYRb'  
} :yAvo4)  
} mGUl/.;yp-  
N-GQ\&   
//日志 C5oIl_t  
public static void log(String sMsg) [oS.B\Vc  
{ yGPi9j{QXq  
System.err.println(sMsg); 1I U*:Z;Rz  
} g$S<_$Iey  
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public static void log(int sMsg) q8vRUlf  
{ %suXp,j  
System.err.println(sMsg); *!+?%e{;b  
} _xXDvBU  
} %i`YJ  
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/* \J^|H@;(@  
**TestMethod.java
>5-]Ur~  
*/ zXg/.
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package NetFox; {~:F1J~=  
pn2_ {8.  
ppM^&6x^  
public class TestMethod { w~=@+U$f  
Z=P=oldH  
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public TestMethod() }[I|oV5*+&  
{ ///xx/weblogic60b2_win.exe as| MB (  
try{ *G0r4Ui$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); b."1p7'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); EYF]&+ 9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kP}91kja  
fileFetch.start(); ?{I]!gI  
} TJp0^&Q  
catch(Exception e){e.printStackTrace ();} >P\/\xL=  
EJ3R{^  
!ZlNPPrq}  
} FqK2[]8  
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public static void main(String[] args) y|@=j~}Zq  
{ - '5OX/Szq  
new TestMethod(); SpUcrK;1  
} oXkxd3  
} <U]#722  
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