http断点续传简单实现（java)

/* ~s-"u *>  
**SiteFileFetch.java mE"},ksg  
*/ ;Ff5oo
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package NetFox; e3}o3c_  
import java.io.*; G\/7V L  
import java.net.*; ,xuA%CF-S  
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public class SiteFileFetch extends Thread { BOWR}n!g  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :{M1]0NH  
long[] nStartPos; //开始位置 |5#iPw_wMY  
long[] nEndPos; //结束位置 k/.a yLq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !R3ZyZcX  
long nFileLength; //文件长度 Y!fgc<]'&  
boolean bFirst = true; //是否第一次取文件 xL}~R7  
boolean bStop = false; //停止标志 A&7~]BR\  
File tmpFile; //文件下载的临时信息 +hzS'z)n&  
DataOutputStream output; //输出到文件的输出流 %TS8 9/  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EbMG9  
public SiteFileFetch(SiteInfoBean bean) throws IOException Erq%Ck(  
{ *;Gnod<  
siteInfoBean = bean;  ];hK5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); oz#;7 ?9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (#5TM1/A  
if(tmpFile.exists ()) m1,yf*U  
{ T;Zv^:]0  
bFirst = false; 
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read_nPos(); $}z%}v  
} pPn
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else w5R?9"d@  
{ bZd)4  
nStartPos = new long[bean.getNSplitter()]; :%kJ9zW  
nEndPos = new long[bean.getNSplitter()]; &N\4/'wV  
} U!Eo*?LU$  
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} Ry4`Q$=:  
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public void run() 3v@Y"I3;  
{ H*VZ&{\7  
//获得文件长度 >TB Rp,;r  
//分割文件 +Qo]'xKr  
//实例FileSplitterFetch Mi2lBEu,  
//启动FileSplitterFetch线程 uZkh.0yB  
//等待子线程返回 _MST8  
try{ PR;A 0   
if(bFirst) )]P%=  
{ Z Vj  
nFileLength = getFileSize(); BIeeu@p  
if(nFileLength == -1) (5R_q.Wu  
{ ?0VETa ~m  
System.err.println("File Length is not known!"); ~$:=hT1  
} :iVEm9pB)  
else if(nFileLength == -2) R4q)FXW29  
{ rIo)'L$
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System.err.println("File is not access!"); ED=P 6u  
} -9@/S$i  
else Mr u  
{ 8>l#F<@5  
for(int i=0;i<nStartPos.length;i++) jO+#$=C  
{ wTK>U`o  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {((|IvP`  
} t?6_^ 08  
for(int i=0;i<nEndPos.length-1;i++) a?5R;I B  
{ }`*DMI;-  
nEndPos = nStartPos[i+1]; ("5Eed  
} z3Ro*yJU  
nEndPos[nEndPos.length-1] = nFileLength; [r;hF  
} J sc`^a%`'  
} -]e@FN
L  
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>+E   
//启动子线程 c</u
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; SJ;Kjq.Qo  
for(int i=0;i<nStartPos.length;i++) ;JAb8dyS2  
{ })^%>yLfc|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |6y(7Ha  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :rhh=nHgn  
nStartPos,nEndPos,i); g_2EH
  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `ot<BwxJ  
fileSplitterFetch.start(); P K9BowlW  
} ~n)<L7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t,>j{SK~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'awZ-$#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |JRaskd  
nEndPos = " + nFileLength); <$ oI  
// fileSplitterFetch[nPos.length-1].start(); ( V^C7ix:  
b am*&E%0K  
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//等待子线程结束 [S#QGB19  
//int count = 0; >UDb:N[  
//是否结束while循环 Wi3St`$  
boolean breakWhile = false; +(qs{07A$  
+PGtO9}B  
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while(!bStop) ,s.{R  
{ Weu%&u-  
write_nPos(); P@pJ^5Jf  
Utility.sleep(500); cW*p
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breakWhile = true; DgB]y6~KXl  
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for(int i=0;i<nStartPos.length;i++) wjnQK  
{ LYvjqNC&4  
if(!fileSplitterFetch.bDownOver) !3 j@gi2  
{ pXBlTZf  
breakWhile = false; Z{gJm9  
break; 7m+d;x2  
} 4kqgZtg.  
} %L;;W,l$`)  
if(breakWhile) U{%N.4:   
break; wdzZ41y1  
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//count++; UxS@]YC  
//if(count>4) 5^+QTQ  
// siteStop(); (iO8[  
} 9u2Mra  
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System.err.println("文件下载结束！"); uxsfQ%3`#  
} C.rLog#  
catch(Exception e){e.printStackTrace ();} VvJ]*D+e  
} *4oj'}  
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//获得文件长度 k~+(X|!5w  
public long getFileSize() nL]-]n;  
{ <~}#Q,9  
int nFileLength = -1; nm.~~h+8M  
try{ h..D1(M  
URL url = new URL(siteInfoBean.getSSiteURL()); @%}4R`S0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1deNrmp%  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?}D|]i34  
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int responseCode=httpConnection.getResponseCode(); VM[U&g<8n  
if(responseCode>=400) Dd:;8Xo  
{ SC6cFyp2  
processErrorCode(responseCode); FsdxLMwk1  
return -2; //-2 represent access is error *'&mcEpg  
} u(92y]3,  
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String sHeader; Nt^9N #+N  
Y Cbt(nmr  
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for(int i=1;;i++) !J@!P?0. C  
{ /18VQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); PpF"n[j  
//Utility.log(in.readLine()); (g>>   
sHeader=httpConnection.getHeaderFieldKey(i); +>,4d  
if(sHeader!=null) _Uxt9 X  
{ bw\a\/Dw  
if(sHeader.equals("Content-Length")) eJv_`#R&Of  
{ Q\ AM] U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); D3BNA]P\2@  
break; =5QP'Qt{O  
} 6JYVC>i  
} w?LDaSz\t  
else Np?%pB!Q  
break; N-g=_86C"  
} [LHx9(,NM  
} A^9RGz4=  
catch(IOException e){e.printStackTrace ();} hQT  p&  
catch(Exception e){e.printStackTrace ();} hb_J.Q  
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Utility.log(nFileLength); zYW+Goz/C  
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return nFileLength; Eoo[)V#x{  
} ee0)%hc1t  
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//保存下载信息（文件指针位置） @TTB$  
private void write_nPos() }%;o#!<N(@  
{ V&75n.L  
try{ j
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output = new DataOutputStream(new FileOutputStream(tmpFile)); .*bu:FuDE  
output.writeInt(nStartPos.length); MI,b`pQ  
for(int i=0;i<nStartPos.length;i++) Q{~WWv  
{ vA r
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// output.writeLong(nPos); =d{B.BP(  
output.writeLong(fileSplitterFetch.nStartPos); 9 Z5!3  
output.writeLong(fileSplitterFetch.nEndPos); !Xzne_V<  
} JQtBt2  
output.close(); DnZkZ;E/  
} s$,gM,|cK  
catch(IOException e){e.printStackTrace ();} #J
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catch(Exception e){e.printStackTrace ();} N5SePA\ ,?  
} *C*'
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//读取保存的下载信息（文件指针位置） RzOs,  
private void read_nPos() S-$N!G~!  
{ :E>"z6H  
try{ \:To>A32  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v9<'nU WVR  
int nCount = input.readInt(); 0E5
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nStartPos = new long[nCount]; *88Q6=Mm  
nEndPos = new long[nCount]; E W{vF|  
for(int i=0;i<nStartPos.length;i++) :=iP_*#  
{ 8?> #  
nStartPos = input.readLong(); %rmn+L),;  
nEndPos = input.readLong(); jOYa}jm?  
} l. 9 i `  
input.close(); *" ("^_x\  
} *K<|E15 ,  
catch(IOException e){e.printStackTrace ();} ODbEL/  
catch(Exception e){e.printStackTrace ();} m=hlim;P,  
} v|WTm#  
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private void processErrorCode(int nErrorCode) ?51Y&gOEZ  
{ !6R;fD#^s  
System.err.println("Error Code : " + nErrorCode); "zn<\z$l  
} * 7<{Xbsj^  
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//停止文件下载 .}wVM`81z  
public void siteStop() q,
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{ oV(|51(f  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) EU@ BNja  
fileSplitterFetch.splitterStop(); RWe$ZZSz!
 
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} _\d[`7#  
} )tq&l>0h  
//负责部分文件的抓取 _XO3ml\x@  
**FileSplitterFetch.java ZCT\4Llv#  
*/ G`_LD+  
package NetFox; zmw <y2`  
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C V{kP8#  
import java.io.*; . paA0j  
import java.net.*; 1kd\Fq^z$  
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public class FileSplitterFetch extends Thread { Cj,Yy  
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String sURL; //File URL pdz_qj!Z  
long nStartPos; //File Snippet Start Position d3m!34
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long nEndPos; //File Snippet End Position '@ $L}C#OI  
int nThreadID; //Thread's ID o*[n[\cR  
boolean bDownOver = false; //Downing is over kK0.j)(  
boolean bStop = false; //Stop identical Q|DVB  
FileAccessI fileAccessI = null; //File Access interface Ap:mc:  
wb#ZRmx}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException bvxol\7;  
{ @d+NeS  
this.sURL = sURL; X6hp}  
this.nStartPos = nStart; Skbd'j  
this.nEndPos = nEnd; Ke*tLnO  
nThreadID = id; 6D=9J
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 u%o]r9xl'  
} un)YK  
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public void run() Rz #&v  
{ ~yGD("X  
while(nStartPos < nEndPos && !bStop) #cnh ~O  
{ ($h`Y;4  
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try{ (R9{wGV [  
URL url = new URL(sURL); Y-&SZI4H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u/I|<NAC,  
httpConnection.setRequestProperty("User-Agent","NetFox"); XY_zFF  
String sProperty = "bytes="+nStartPos+"-"; nQtp4  
httpConnection.setRequestProperty("RANGE",sProperty); ?g6xy[  
Utility.log(sProperty); JB <GV-l  
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InputStream input = httpConnection.getInputStream(); _x2i=SFo*$  
//logResponseHead(httpConnection); -J06H&/k  
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byte[] b = new byte[1024]; 6H#4iMeh  
int nRead; C'wRF90  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Sb/`a~q^  
{ xa=Lu?t%<  
nStartPos += fileAccessI.write(b,0,nRead); a7?)x])e  
//if(nThreadID == 1) x @a3STKT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]SO-NR  
} MyJ\/`8  
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'&;s32']}  
Utility.log("Thread " + nThreadID + " is over!"); oy _DYop  
bDownOver = true; <27:O,I  
//nPos = fileAccessI.write (b,0,nRead); .:b&$~<  
}  Fhk 8  
catch(Exception e){e.printStackTrace ();} >iKbn  
} jO5,PTV  
} OxC8xB;`  
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//打印回应的头信息 Z)7|m  
public void logResponseHead(HttpURLConnection con) <Wwcd8d  
{ 4#D<#!]^  
for(int i=1;;i++) 7~I*u6zY  
{ t/kMV6
 
String header=con.getHeaderFieldKey(i); w<P$)~6  
if(header!=null) wAvnj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *6`};ASK  
Utility.log(header+" : "+con.getHeaderField(header)); Fmd^9K  
else !1
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break; 5fT"`FL?  
} auai@)v6  
} ;usR=i36b  
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public void splitterStop() :f/T$fa*  
{ |c)hyw?[Y  
bStop = true; :,@\q0j"=  
} TOx >Z  
}<9IH%sgF  
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} @CUYl*.PD  

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kR !O-@GJ]  
/* 6/=0RTd  
**FileAccess.java b)(rlX  
*//文件访问(定位，写) d$gT,+|vu  
package NetFox; #GbfFoE  
import java.io.*; }|j\QjH  
_-R&A@  
? koIZ  
public class FileAccessI implements Serializable{ ~x-v%x6  
 
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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 O!U8"Yr$  
RandomAccessFile oSavedFile; `:Bm@eN  
long nPos; 7/969h^s  
us7t>EMmB  
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public FileAccessI() throws IOException !j8 DCVb  
{ LZI[5tA"  
this("",0); `Q!#v{  
} Oj,v88=  
Q&@e,7]V+  
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public FileAccessI(String sName,long nPos) throws IOException )7jJ3G*  
{ xCYK"v6\  
oSavedFile = new RandomAccessFile(sName,"rw"); 4c'F.0^  
this.nPos = nPos; _wp_y-"  
oSavedFile.seek(nPos); \5pBK  
} WZQ EBXs  
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>At* jg48  
public synchronized int write(byte[] b,int nStart,int nLen) @d1YN]ede  
{ 3Jh!YzI8  
int n = -1; l8~s#:v6X  
try{ %Ek!3t  
oSavedFile.write(b,nStart,nLen); hqW),^\>'  
n = nLen; (Zz8 ldO  
} dQQ!QbI(.  
catch(IOException e) 6BdK)s  
{ ) -^(Su(!  
e.printStackTrace (); @j`gxM_-O  
} 53<.Knw5a  
p&$O}AX|  
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return n; /iw$\F |8  
} 35KRJY#  
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#;])/8R%  
} NyR,@n1  
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/* cfC}"As  
**SiteInfoBean.java V)Sw\tS6g  
*/ 7SJbrOL4Q-  
package NetFox; ^5n#hSqZ=M  
PSHzB! H=n  
<f9a%`d  
public class SiteInfoBean { [C`LKA$t  
<]f{X<ef  
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private String sSiteURL; //Site's URL !!+LFe4su  
private String sFilePath; //Saved File's Path ;wa#m1  
private String sFileName; //Saved File's Name VD~ %6AjyN  
private int nSplitter; //Count of Splited Downloading File "8iIOeY-\  
GCj[ySCD  
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public SiteInfoBean() :ggXVwpe  
{//nSplitter的缺省值为5 .(%]RSBY  
//default value of nSplitter is 5 |
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this("","","",5); D%*Ryg  
} -A^o5s  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ):]5WHYg  
{ vyvb-oz;u  
sSiteURL= sURL; L]*5cH  
sFilePath = sPath; G$[Hm\V  
sFileName = sName; gx.\&W b  
this.nSplitter = nSpiltter; Yq>K1E|  
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} %z6_,|%  
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public String getSSiteURL() kD me>E=  
{ AD~
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return sSiteURL; B8~bx%)3T  
} F<4>g+Ag  
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public void setSSiteURL(String value) }U
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{ Ce/D[%  
sSiteURL = value; /V }Z,'+  
} FA{'Ki`  
meYGIP:n  
v,!`A!{D  
public String getSFilePath() ~NTKWRaR  
{ Zg9VkL6Z6  
return sFilePath; CT/>x3o  
} fRjp(m  
AO,^v+$  
vty:@?3\  
public void setSFilePath(String value) .cz7jD  
{ wUfm)Q#  
sFilePath = value; `$MO;Fv,G  
} uT>"(wnJ|  
jN!VrRA  
jdkqJ4&i  
public String getSFileName() %6la@i  
{ u s8.nL/  
return sFileName; \olY)b[  
} Z>[n~{-,p  
0|kH0c,T-  
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public void setSFileName(String value) E.,  
{ BP@V:z  
sFileName = value; 0jt@|
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} dKY#Tl]  
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public int getNSplitter() iD<}r?
Z  
{ %@8#+#@J0  
return nSplitter; C@g/{?\  
} q|
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]*D~>q"#\  
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public void setNSplitter(int nCount) ^iWJqpLe  
{ g"N&*V2  
nSplitter = nCount; P?@o?  
} p)?6~\F:  
}  `7oYXk  
/m4Y87
 
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/* 8Vy/n^3)  
**Utility.java 1.5R`vKn]  
*/ b#*"eZj
 
package NetFox; ,ZVhL* "  
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public class Utility { </b_Rar  
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public Utility() Gr'|nR8  
{ NZ?dJ"eq7  

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8@ f+?g*i  
} jhkXU+4  
tF\_AvL_8  
//线程睡眠 ANfy+@  
public static void sleep(int nSecond) iu$Y0.H@  
{ _YN C}PUU  
try{ g9Ty%|Q7(  
Thread.sleep(nSecond); c<sq0('`  
} 8T8]gM  
catch(Exception e) PAH#yM2Ic  
{  yyGn<  
e.printStackTrace (); Gz4LjMQ &  
} 7eW6$$ju,N  
} C}ASVywc,1  
nW`] =
 
//日志 ^V7)V)Z;0  
public static void log(String sMsg) |pBvy1e4)  
{ t^2$ent  
System.err.println(sMsg); :(
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} )@<HG$#  
|{RCvm  
9v1Snr  
public static void log(int sMsg) {;Oj  
{ 9m<%+S5&  
System.err.println(sMsg); U;*O7K=P  
} ce*?crOV  
} Kw2]J)TO
 
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/* g`~;"%u7cn  
**TestMethod.java 2wa'WEx  
*/ 9i D&y)$"  
package NetFox; v^;vH$B  
..w$p-1  
" t?44[  
public class TestMethod { Hz=s)6$ey  
*?VB/yO=0  
$ab{GxmX'4  
public TestMethod() SjIDzNI5  
{ ///xx/weblogic60b2_win.exe z2Z}mktP  
try{ .EvP%A m  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h)aLq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k=G c#SD5_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); nU0##  
fileFetch.start(); @H^\PH?pp  
} x=X&b%09  
catch(Exception e){e.printStackTrace ();} r?dkE=B  
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} F5OQM?J  
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public static void main(String[] args) mX, @yCI  
{ er2;1TW3E  
new TestMethod(); EfkBo5@Qi  
} M:L-j{?y_  
} v- p8~u1N  
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