http断点续传简单实现（java)

/* )Ga6O2:  
**SiteFileFetch.java t|q=NK/  
*/ }>w; +XU  
package NetFox; d?K8Ygz  
import java.io.*; dO@iq^9-  
import java.net.*; 8ah]D  
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public class SiteFileFetch extends Thread { a$GKrc,z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7Av]f3Zr  
long[] nStartPos; //开始位置 lO *Hv9#  
long[] nEndPos; //结束位置 4L0LT>'M\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c"xaN  
long nFileLength; //文件长度 pIXQ/(h31  
boolean bFirst = true; //是否第一次取文件 ox6rR  
boolean bStop = false; //停止标志 .DQ]q o]OG  
File tmpFile; //文件下载的临时信息 ^#o.WL%4/B  
DataOutputStream output; //输出到文件的输出流 u *< (B  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %9lxE[/  
public SiteFileFetch(SiteInfoBean bean) throws IOException l0_V-|x  
{ q mB@kbt  
siteInfoBean = bean; :wZZ 1qa  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); by<2hLB9Q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |2# Ro*  
if(tmpFile.exists ()) u;!Rv E8N  
{ `+uXL9
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bFirst = false; ~
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read_nPos(); $enh45Wy  
} h2>0#Vp3j  
else ,&-[$,  
{
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nStartPos = new long[bean.getNSplitter()]; [wR8q,2  
nEndPos = new long[bean.getNSplitter()]; U*@_T3N  
} -}J8|gwwp  
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} H[r0jREK  
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public void run() j66@E\dN  
{ #vSI_rt9I  
//获得文件长度 b<n)`;  
//分割文件 %?fzT+-=%  
//实例FileSplitterFetch }>w4!  
//启动FileSplitterFetch线程 4Z] 35*  
//等待子线程返回 C#Jj;Gd  
try{ msylb~^  
if(bFirst) J^:~#`8  
{ d%hA~E1rR  
nFileLength = getFileSize(); 3fPv71NVtt  
if(nFileLength == -1) A=K1T]o  
{ wLbngO=VG  
System.err.println("File Length is not known!"); =Ug_1w  
} .p`'^$X^  
else if(nFileLength == -2) 
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{ X\%3uPQ  
System.err.println("File is not access!"); :+Kesa:E  
} 5*$Zfuf  
else 2e"}5b5  
{ 9x!y.gx  
for(int i=0;i<nStartPos.length;i++)
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{ vknFtpx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); BE~[%6T7  
} ;"Y6&YP<  
for(int i=0;i<nEndPos.length-1;i++) #F@7>hd1  
{ M6iKl  
nEndPos = nStartPos[i+1]; OT i3T1&  
} BP$#a
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nEndPos[nEndPos.length-1] = nFileLength; vvxj{fxb)  
} 4(82dmKO  
} }3 }=tN5  
([~`{,sv  
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//启动子线程 1tdCzbEn+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vEGK{rMA  
for(int i=0;i<nStartPos.length;i++) "=.|QKC1`  
{ 5ov%(QI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :(Bi{cw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $Stu-l1e a  
nStartPos,nEndPos,i); $P3nP=mf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [3Rj?z"S  
fileSplitterFetch.start(); ?sYjFiE  
} &v,p_'k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hea<!zPH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); hT"K}d;X  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W<"\hQI  
nEndPos = " + nFileLength); =L%3q<]p  
// fileSplitterFetch[nPos.length-1].start(); [<QWTMjR  
'Aj>+H<B  
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//等待子线程结束 wjOAgOC  
//int count = 0; Sj?sw]3  
//是否结束while循环 K5&C}Ey1  
boolean breakWhile = false; LnS>3$t*  
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while(!bStop) VWt'Kx"  
{ (+dRD]|T  
write_nPos(); vq1&8=  
Utility.sleep(500); G`"Cqs<  
breakWhile = true; <>_WdAOuD  
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for(int i=0;i<nStartPos.length;i++) ~b0qrjF;O  
{ WmUW i
{  
if(!fileSplitterFetch.bDownOver) A#&qo
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{ (p=GR#  
breakWhile = false; R"`{E,yj  
break; :* b4/qpYv  
} =fK'Ep[  
} om?CFl  
if(breakWhile) ~-wJ#E3g  
break; X:&p9_O@  
0z7mre^Q  
_9|@nUD  
//count++; G6{A[O[  
//if(count>4) *J5RueUG  
// siteStop(); |wQZ~Ux:  
} X388Gs;e  
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System.err.println("文件下载结束！"); [nIG_j>D-f  
} 389.&`Q%Ut  
catch(Exception e){e.printStackTrace ();} 'hw@l>1\9  
} U^BXCu1km  
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//获得文件长度 cu!bg+,zl  
public long getFileSize()  iLcadX  
{ %C0O?q  
int nFileLength = -1; UQ])QTrZFi  
try{ e uHu}  
URL url = new URL(siteInfoBean.getSSiteURL()); GY]6#
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %W',cu  
httpConnection.setRequestProperty("User-Agent","NetFox"); |!5T+H{Sj  
9w;J7jgOT!  
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int responseCode=httpConnection.getResponseCode(); 1[g!^5W  
if(responseCode>=400) Fi%W\Y'  
{ gzCMJ<3!D  
processErrorCode(responseCode); I S8nvx\  
return -2; //-2 represent access is error u;ooDIq@  
} F%Umau*1  
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String sHeader; ^@lg5d3F  
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for(int i=1;;i++) wU)5Evp[  
{ LiD |4(3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LYg$M@  
//Utility.log(in.readLine()); RG r'<o)  
sHeader=httpConnection.getHeaderFieldKey(i); Po11EZa$a  
if(sHeader!=null) m4U+,|Fa  
{ WfT)CIKs  
if(sHeader.equals("Content-Length")) X#I`(iHY  
{ m2q;^o:J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;AGs1j  
break; 3k*:B~1  
} U"y'Kd  
} _7.GzQJ  
else |+xtFe  
break; ca3BJWY}J  
} )):22}I#  
} GHC?Tp  
catch(IOException e){e.printStackTrace ();} ^x"c0R^  
catch(Exception e){e.printStackTrace ();} <ivqe"m  
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Utility.log(nFileLength); u4,X.3V]A  
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return nFileLength; 1;:t~Y  
} nR@,ouB-$  
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//保存下载信息（文件指针位置） =#Cf5s6qt  
private void write_nPos() h3]@M$Y[  
{ fZV8
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try{ 7|M
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output = new DataOutputStream(new FileOutputStream(tmpFile)); U]!.~ji3  
output.writeInt(nStartPos.length); xe gL!  
for(int i=0;i<nStartPos.length;i++) fJ&<iD)6  
{ [zTYiNa  
// output.writeLong(nPos); PMN2VzE4{  
output.writeLong(fileSplitterFetch.nStartPos); Ns|V7|n]  
output.writeLong(fileSplitterFetch.nEndPos); u->@|tEq  
} OT}Yr9h4  
output.close(); O`[iz/7m  
} ;Ma/b=Y  
catch(IOException e){e.printStackTrace ();} F'>GN}n  
catch(Exception e){e.printStackTrace ();} a
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} Q_]!an(  
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//读取保存的下载信息（文件指针位置） N{V5 D  
private void read_nPos() bg1"v a#2  
{ 1;Wkt9]9  
try{ Fi?Q 4b  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); N?=qEX|R  
int nCount = input.readInt(); C*EhexK,}  
nStartPos = new long[nCount]; 2 ]DCF  
nEndPos = new long[nCount]; 7Z`Mt9:Ht  
for(int i=0;i<nStartPos.length;i++) N[bR&#p  
{ eC^0I78x  
nStartPos = input.readLong(); <5ft6a2fQ  
nEndPos = input.readLong(); %eJ\d?nw  
} 3r-VxP 5n  
input.close(); I`"-$99|t1  
} o[6vxTH  
catch(IOException e){e.printStackTrace ();} vTMP&a'5L  
catch(Exception e){e.printStackTrace ();} e>,9]{N+$  
} 9QOr,~~s  
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private void processErrorCode(int nErrorCode) {8{t]LK<  
{ 8_<&f%
/  
System.err.println("Error Code : " + nErrorCode); oP=T6PX~l  
} a81!~1A  
'"xL}8HX}  
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//停止文件下载 3b|7[7}&  
public void siteStop() o%Uu.P  
{ L_Y9+ e  
bStop = true; )RA\kZ"  
for(int i=0;i<nStartPos.length;i++) jiwpDB&[  
fileSplitterFetch.splitterStop(); 9 wSl,B-  
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1#>&p%P!  
} J@k
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} -}_cO|kk  
//负责部分文件的抓取 'NT#
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**FileSplitterFetch.java waXDGdl0  
*/ cyGN3t9`.  
package NetFox; ?#BZ `H  
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#aitESbT  
import java.io.*; WyBQ{H{So  
import java.net.*; QIij
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public class FileSplitterFetch extends Thread { Y)Znb;`?a  
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String sURL; //File URL ;OQ'B=uK  
long nStartPos; //File Snippet Start Position aQ!9#d_D  
long nEndPos; //File Snippet End Position Pn'`Q S?  
int nThreadID; //Thread's ID X
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boolean bDownOver = false; //Downing is over y3={NB+  
boolean bStop = false; //Stop identical `d}W;&c  
FileAccessI fileAccessI = null; //File Access interface I"8d5a}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8qFUYZtY  
{ 69[V <1  
this.sURL = sURL; !y>lOw})Q  
this.nStartPos = nStart; yfSiByU  
this.nEndPos = nEnd; DC
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nThreadID = id; 6C:x6'5[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 kf+JM/  
} q3c*<n g#  
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public void run() ]PR|d\O  
{ K,x$c %  
while(nStartPos < nEndPos && !bStop) tr}KPdE  
{ PoYr:=S?  
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try{ 'v'` F*6  
URL url = new URL(sURL); xNC* ]8d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -d|BO[4j  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5wzQ?07T_  
String sProperty = "bytes="+nStartPos+"-"; Hi]vHG(  
httpConnection.setRequestProperty("RANGE",sProperty); ojN`#%X  
Utility.log(sProperty); a
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InputStream input = httpConnection.getInputStream(); _, \y2&KT  
//logResponseHead(httpConnection); f*{M3"$E  
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byte[] b = new byte[1024]; _wm
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int nRead; $!3gN%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /\TQc-k?2  
{ ,(j>)g2Ob  
nStartPos += fileAccessI.write(b,0,nRead); 4]"a;(  
//if(nThreadID == 1) ..??O^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4|zd84g  
} b%3Q$wIJ6  
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Utility.log("Thread " + nThreadID + " is over!"); e.h~[^zg  
bDownOver = true; +DicP"~*  
//nPos = fileAccessI.write (b,0,nRead); gb]hOB7g  
} @kwLBAK}@  
catch(Exception e){e.printStackTrace ();} SW3wMPy&s  
} i Bi7|  
} {udrT"h  
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V)2"l"Kt  
//打印回应的头信息 &\&'L|0F  
public void logResponseHead(HttpURLConnection con) GMEw  
{ `if
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for(int i=1;;i++) :_MP'0QP  
{ ?O!]8k`1$  
String header=con.getHeaderFieldKey(i); I_:t}3s  
if(header!=null) :L]-'\y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); NU|qX {-  
Utility.log(header+" : "+con.getHeaderField(header)); _mw13jcN]  
else 53bM+  
break; 1T!cc%ah  
} Lqg]Fd  
} U!x0,sr  
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public void splitterStop() 3b<: :t  
{ O-i4_YdVt  
bStop = true; ?x:m;z/  
} _i-\mR_~  
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} \^yXc*C  
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/* \.5F](:  
**FileAccess.java .H ,pO#{;  
*//文件访问(定位，写) Dp^"J85}   
package NetFox; &8Zeq3~  
import java.io.*; T0g0jr{  
1JIG+ZNmd  
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public class FileAccessI implements Serializable{ kl| g  
3*G5F}7%=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {!lNL[x  
RandomAccessFile oSavedFile; Cm^Ylp  
long nPos; T&]Na  
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public FileAccessI() throws IOException Dq|GQdZ>o  
{ ya#RII']  
this("",0); iA]DE`S  
} n4Vwao/9x  
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public FileAccessI(String sName,long nPos) throws IOException [Uswf3  
{
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oSavedFile = new RandomAccessFile(sName,"rw"); |0lLl^zp  
this.nPos = nPos; Qr<AV:  
oSavedFile.seek(nPos); ^,LtEwd~Y  
} I<sfN'FpT  
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public synchronized int write(byte[] b,int nStart,int nLen) !-7_ +v>  
{ >#INEO  
int n = -1; x9h?e`  
try{ ;r3}g"D@  
oSavedFile.write(b,nStart,nLen); )Q~C4C-j  
n = nLen; xF&6e&nv  
} H*GlWgfG  
catch(IOException e) {yTpRQN~  
{ ]{<saAmJC  
e.printStackTrace (); 2.ew^D#
 
} kj-=xhJ{=  
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return n; >d#3|;RY  
} I,]J=xi  
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} a%v>eXc  
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/* Vn^)  
**SiteInfoBean.java Zd$JW=KR]l  
*/ Z4#v~!  
package NetFox; oooS s&t  
},&h[\N{6  
9976H\{  
public class SiteInfoBean { .8K6C]gw  
~JLYhA^'+<  
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private String sSiteURL; //Site's URL 76_<xUt{  
private String sFilePath; //Saved File's Path N\'TR6_,b  
private String sFileName; //Saved File's Name !W~QT}  
private int nSplitter; //Count of Splited Downloading File X{`1:c'x  
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public SiteInfoBean()
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{//nSplitter的缺省值为5 "-P/jk  
//default value of nSplitter is 5 f}2;N  
this("","","",5); Je 31".  
} IytDvz*|  
$T?]+2,6;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V:OiW"/  
{ Jr]gEBX  
sSiteURL= sURL; *!w25t  
sFilePath = sPath; 2$tQ @r  
sFileName = sName; yyjw?#\8  
this.nSplitter = nSpiltter; |kseKZ3  
*,&S',S-  
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} Kr]z]4.d@  
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public String getSSiteURL() +j.qZ8  
{ Q ?^4
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return sSiteURL; t3a#%'Dv  
} e^8BV;+c  
*7Xzht&f  
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public void setSSiteURL(String value) Gc'M[9Mh  
{ lH6fvz  
sSiteURL = value; o<r
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} nE$ f  
j;+["mi  
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public String getSFilePath() *{|$FQnR>(  
{ oqYt/4^Q  
return sFilePath; ceG&,a$\  
} A?r^V2+j  
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VX!hv`E  
public void setSFilePath(String value) :BD>yOlG  
{ s4bv;W  
sFilePath = value; 5z Kqb  
} ]Jn2Ra"j  
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public String getSFileName() mf9hFy*<4  
{ Mg\TH./Y:  
return sFileName; *VDVC0R  
} )N
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i
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]-bQNYKX  
public void setSFileName(String value)  n}OU Y  
{ |vz9Hs$@l  
sFileName = value; 96}eR,  
} 1qZG`Vz  
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public int getNSplitter() !}t-j3bCs  
{ V%51k{  
return nSplitter; r]T0+
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} (:7a&2/M  

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public void setNSplitter(int nCount) CN\=9Rvs  
{ yb?|Eww_o  
nSplitter = nCount; x*q35K^PE  
} V:Mk)8Gf|  
} `tVy_/3(9  
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9.s,:?5e  
/* l9J*um-  
**Utility.java #U"1 9@|}  
*/ NzlAC  
package NetFox; Ao"C<.gUYP  
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public class Utility { Dr+
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public Utility() Mk5RHDh  
{ $3\
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} ^Xs]C|=W  
q.T:0|  
//线程睡眠 H,K`6HH  
public static void sleep(int nSecond) ?1w"IjUS  
{ B;W(iI  
try{ X8R1a?  
Thread.sleep(nSecond); pkk4h2Ah  
} "dtlME{Bx  
catch(Exception e) t!qwxX*$T  
{ |}Ph"g2D,  
e.printStackTrace (); t9` Ed>a  
} Ct!S T
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} !*vBW/  
vD26;S.y[a  
//日志 X"<|Z]w  
public static void log(String sMsg) {[^#h|U  
{ Ep ">v>"  
System.err.println(sMsg); bV6V02RF  
} {7X~!e|w  
a+ GJVJ  
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public static void log(int sMsg) wW5Yw i  
{ i/$SN-5}1  
System.err.println(sMsg); ,YB1 y)x  
} C6^j#rl  
} 5[R?iSGL1  
l$M +.GB<  
gtYRV*^q  
/* "8/dD]=f^a  
**TestMethod.java !y*oF{RZ  
*/ U^?= 0+  
package NetFox; J?D\$u:  
1;&T^Gdj  
tX?J
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public class TestMethod { |GuEGmR  
(/?R9T[V&^  
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public TestMethod() 2w4MJ,Uw  
{ ///xx/weblogic60b2_win.exe ri+U0[e3  
try{ vr4S9`,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ue7 6py9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [:B*6FXMN~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 88o:NJ}_  
fileFetch.start(); c<jB6|.=2  
} /gw Cwyo  
catch(Exception e){e.printStackTrace ();} i@,]Z~]  
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} ( 3;`bvYH"  
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*rf$>8~$n  
public static void main(String[] args) aR)?a;}H  
{ *Hu
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new TestMethod(); \ja `c)x  
} GYoseqZM  
} .'lN4x  
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