http断点续传简单实现（java)

/* {cm?Q\DT  
**SiteFileFetch.java *): |WDR  
*/ ~=|}!A(  
package NetFox; $Z@*!B^  
import java.io.*; Z+El(f x  
import java.net.*; UX)GA[WI  
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public class SiteFileFetch extends Thread { P8d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean u
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long[] nStartPos; //开始位置 Y!<m8\  
long[] nEndPos; //结束位置 ]@&X*~c^Z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p;+O/'/j  
long nFileLength; //文件长度 J2=4%#R!  
boolean bFirst = true; //是否第一次取文件 2Vx4"fHP#N  
boolean bStop = false; //停止标志 4D?h}U /  
File tmpFile; //文件下载的临时信息 {[H_Vl@  
DataOutputStream output; //输出到文件的输出流 ]01`r/->\  
8
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3(BL  
public SiteFileFetch(SiteInfoBean bean) throws IOException *7!MG  
{ ;I>nA6A  
siteInfoBean = bean; 46:<[0Psl/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /Y0~BQC7!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); B.8B1MFm  
if(tmpFile.exists ()) V\L;EHtc$  
{ F!vrvlD`s  
bFirst = false; t+?Bb7p,H  
read_nPos(); b"I#\;Ym  
}
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else  FOiwA.:0  
{ !nBbt?*  
nStartPos = new long[bean.getNSplitter()]; W:r[o%B  
nEndPos = new long[bean.getNSplitter()]; =g#PP@X]D!  
} 4S_f2P2J  
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} YkKu4f  
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public void run() -nb U5o  
{ 9)!Ksg(h  
//获得文件长度 7P{= Pv+  
//分割文件 S@,/
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//实例FileSplitterFetch 4E''pW]8  
//启动FileSplitterFetch线程 C @Ts\);^  
//等待子线程返回 K$S0h-?9]O  
try{ .O-)m'5  
if(bFirst) =D(a~8&,  
{ #}~tTL  
nFileLength = getFileSize(); ioi/`iQR  
if(nFileLength == -1) SgU@`Pb  
{ #/qcp|m  
System.err.println("File Length is not known!"); RRO@r}A!y  
} @fd<  
else if(nFileLength == -2) neEqw+#Z  
{ e
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System.err.println("File is not access!"); IjhRSrCv  
} 2f(`HSC'  
else Zr}>>aIJ]k  
{ A+/Lt>+AS  
for(int i=0;i<nStartPos.length;i++) JQ+Mg&&Q  
{ r`"_D%kc  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oIrc))j,$  
} HVM%B{(  
for(int i=0;i<nEndPos.length-1;i++) M>k&WtqK  
{ }cz
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nEndPos = nStartPos[i+1]; 'bfxQ76@sa  
} Md6u4c  
nEndPos[nEndPos.length-1] = nFileLength; wGO-Z']i  
} .r/s.g  
} }Z <I%GT  
=o@}~G&HA  
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//启动子线程 i%yKyfD  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; za6 hyd^  
for(int i=0;i<nStartPos.length;i++) $I5|rB/4?  
{ |mhKD#:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $;g*s?F*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >(:3H+  
nStartPos,nEndPos,i); ?3DL .U{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fTmJDUv+  
fileSplitterFetch.start(); H8HH) ^  
} :{w3l O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <,Gjo]z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1drg5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d Np%=gIj  
nEndPos = " + nFileLength); z{.&sr>+v  
// fileSplitterFetch[nPos.length-1].start(); #cR5k@  

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8Ogg(uS70'  
//等待子线程结束 V xN!Ki=  
//int count = 0; m<Gd 6V5  
//是否结束while循环 qPu?rU{2  
boolean breakWhile = false; El}~3|a?  
 ^Oj^7.T+  
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while(!bStop) BDN}`F[F  
{ *4 m]UK  
write_nPos(); w_@6!zm  
Utility.sleep(500); NrcV%-+u%  
breakWhile = true; ^g'uR@uU  
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for(int i=0;i<nStartPos.length;i++) &w_8E+YZ  
{ TbqtT_{  
if(!fileSplitterFetch.bDownOver) Kd}%%L  
{ @$b7 eu  
breakWhile = false; vSQB~Vw8t  
break; .ErR-p=-  
} ~LH).\V  
} 3&X5*-U  
if(breakWhile) ubl Y%{"  
break; ?:PF
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gd)VL}
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//count++; nQw, /Lk  
//if(count>4) f]+. i-c=  
// siteStop(); 2$Z4 >!  
} ]VVx2ERs  
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System.err.println("文件下载结束！"); \a:-xwUu<  
} ]xJ2;{JWsO  
catch(Exception e){e.printStackTrace ();} $nthMx$  
} N8wA">u  
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!O,`Z`T?  
//获得文件长度 S?H qrf7<  
public long getFileSize() ?cr^.LV|h^  
{ ( Qk*B  
int nFileLength = -1; ds+0y;vc  
try{ k1^&;}/f:  
URL url = new URL(siteInfoBean.getSSiteURL()); uY)|   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7baQ4QY?n  
httpConnection.setRequestProperty("User-Agent","NetFox"); M-f; ,>  
o 3 G*   
$T'lWD*  
int responseCode=httpConnection.getResponseCode(); /vPc
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if(responseCode>=400) {Pi]i?  
{ sU?%"q  
processErrorCode(responseCode); "IdN*K  
return -2; //-2 represent access is error P_c9v/  
} dBp)6ok#c  
`oH6'+fT`;  
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String sHeader; jTz~ V&^  
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for(int i=1;;i++)  Hn,;G`{  
{ B}p{$g!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^{fA:N=  
//Utility.log(in.readLine()); lxD~[e  
sHeader=httpConnection.getHeaderFieldKey(i); )KD*G;<O]L  
if(sHeader!=null) 1lQO`CmR6M  
{ B"I^hrQ  
if(sHeader.equals("Content-Length")) ?,x3*'-(  
{ _0e;&2')  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0)-yLfTn  
break; Wi{ jC?2Q  
} %FO#j6  
} sM'%apM#  
else N(^ q%eHp  
break; G$$y\e$  
} 1$ C\`  
} 6w:M_tDM  
catch(IOException e){e.printStackTrace ();} BO)Q$*G~JD  
catch(Exception e){e.printStackTrace ();} r5g:#m
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Utility.log(nFileLength); [oh0 )wzB  
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return nFileLength; `8D}\w<eI  
} ?B~S4:9  
},LO
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//保存下载信息（文件指针位置） hMvLx>q3)  
private void write_nPos() "nEfk{g  
{ ~*Kk+w9H<  
try{ B)}.
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output = new DataOutputStream(new FileOutputStream(tmpFile)); DqGm
 
output.writeInt(nStartPos.length); m]#oZVngy  
for(int i=0;i<nStartPos.length;i++) UiLiy?EJ  
{ RO+N>Wkt  
// output.writeLong(nPos); !O}^Y  
output.writeLong(fileSplitterFetch.nStartPos); HSsG0&'-Y  
output.writeLong(fileSplitterFetch.nEndPos); FH}2wO~_  
} sV`!4 u7%}  
output.close(); ~SN *  
} AeN$AqQd/  
catch(IOException e){e.printStackTrace ();} )eaEc9o>  
catch(Exception e){e.printStackTrace ();} R *uwp'@  
} lqoJ2JMy  
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//读取保存的下载信息（文件指针位置） _8I\!  
private void read_nPos() n3Q Rn^  
{ nqMXE82  
try{ nkAS]sC  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "|KhqV=?v  
int nCount = input.readInt(); GLE/ 1  
nStartPos = new long[nCount]; (764-iv(  
nEndPos = new long[nCount]; AkE(I16Uy~  
for(int i=0;i<nStartPos.length;i++) &;wNJ)
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{
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nStartPos = input.readLong(); y8arFG  
nEndPos = input.readLong(); Z]\VOA>  
} 3JJE
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input.close(); [;RO=  
} O; #qG/b1  
catch(IOException e){e.printStackTrace ();} )~[rb<:)b  
catch(Exception e){e.printStackTrace ();} x^]J^L45  
} si=m5$V  
)j/b`V6  
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private void processErrorCode(int nErrorCode)
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{ O ! iN  
System.err.println("Error Code : " + nErrorCode); =Y`e?\#`  
} I92orr1  
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//停止文件下载 (R|Ftjs .  
public void siteStop() H05xt
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{ M>_ U9g  
bStop = true; 8qF OO3c\V  
for(int i=0;i<nStartPos.length;i++) 'M!*Ge  
fileSplitterFetch.splitterStop(); 3EO:Uk5<  
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} TKs l.|  
} ~;/}D0k$x  
//负责部分文件的抓取 *pj
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**FileSplitterFetch.java -ztgi
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*/ ,LftQ1*;  
package NetFox; h6~H5X  
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import java.io.*; +Jw+rjnP  
import java.net.*; U#>K(  
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public class FileSplitterFetch extends Thread { GMOnp$@H^s  
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i)=dp!Bx^  
String sURL; //File URL `RHhc{  
long nStartPos; //File Snippet Start Position A3eus
 
long nEndPos; //File Snippet End Position `/RcE.5n\@  
int nThreadID; //Thread's ID pKNrEq  
boolean bDownOver = false; //Downing is over CKy/gTN  
boolean bStop = false; //Stop identical BRTCo,i  
FileAccessI fileAccessI = null; //File Access interface x=YV*  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException OKV/=]GS  
{ ^t}8E2mq  
this.sURL = sURL; gn)>(MG  
this.nStartPos = nStart; V)jF]u~g  
this.nEndPos = nEnd; 9^g?/8  
nThreadID = id; nh*hw[Ord  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +<rWYF(ii/  
} 0x,NMS  
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public void run() \'.|7{Xu  
{ ?5j}&Y3  
while(nStartPos < nEndPos && !bStop) k] iy
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{ L
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try{ ^8V8,C)  
URL url = new URL(sURL); +j(7.6ia  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )R6-]TkA_  
httpConnection.setRequestProperty("User-Agent","NetFox"); UH`cWVLpr  
String sProperty = "bytes="+nStartPos+"-"; sUz,F8G  
httpConnection.setRequestProperty("RANGE",sProperty); 'cPE7uNT  
Utility.log(sProperty); "U|u-ka8B  
4,.[B7irR  
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InputStream input = httpConnection.getInputStream(); bBY7^k  
//logResponseHead(httpConnection); ]o($No  
#tN!^LLi  
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byte[] b = new byte[1024]; &f-x+y  
int nRead; 1T0s UIY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a[ yyEgm2  
{ e/R$Sfj
]  
nStartPos += fileAccessI.write(b,0,nRead); 1eOQ;#OV  
//if(nThreadID == 1) *]*0
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); irF+(&q]jh  
} Dd'J"|jF38  
[7Liken  
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Utility.log("Thread " + nThreadID + " is over!"); hxkwT  
bDownOver = true; _18Aek  
//nPos = fileAccessI.write (b,0,nRead); @*=eqO  
} l,ic-Y1  
catch(Exception e){e.printStackTrace ();} h3j`X'  
} O #5`mo  
} B3W2?5p  
IHwoG(A~<  
bKQ_{cR  
//打印回应的头信息 }BAe   
public void logResponseHead(HttpURLConnection con) ONMR2J(  
{ />O.U?  
for(int i=1;;i++) +pxt
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{ Nt~G {m  
String header=con.getHeaderFieldKey(i); XGAR8=tic  
if(header!=null) Ygc.0VKMR  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  / !aVv  
Utility.log(header+" : "+con.getHeaderField(header)); ,'byJlw_pv  
else +\RviF[+  
break; /! M%9gu  
} yAQ)/u[|  
} T1c&3  
3XhLn/@  
w_*$wVl
 
public void splitterStop() TRFza}4:i  
{ xG|lmYt76  
bStop = true; %";ap8J04F  
} RY
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* & : J  
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} :8Ugz~i  
!_?#f|  
-932[+  
/* !-tVt D  
**FileAccess.java QURpg/<U  
*//文件访问(定位，写) <AB({(  
package NetFox; "LM[WcDX  
import java.io.*; \N.Bx
  
v K!vA-7  
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public class FileAccessI implements Serializable{ J'*`K>wV  
+m1*ou'K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _FzA
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RandomAccessFile oSavedFile; Z8o8>C\d9/  
long nPos; G],W{<Pe  
oA4<AJ2  
3
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public FileAccessI() throws IOException JxQGL{) >  
{ ^@;P-0Sy  
this("",0); du&9mOrr  
} AX6l=jFZx  
/H*n(d  
_aw49ag;  
public FileAccessI(String sName,long nPos) throws IOException $`_xP1bUT  
{ ?, cI!c`  
oSavedFile = new RandomAccessFile(sName,"rw"); P.kf|,8L  
this.nPos = nPos; Z+ )<FX  
oSavedFile.seek(nPos); YT<(2u#Ng  
} f&? 8fB8{  
xn}HB  
#g]eDU-[  
public synchronized int write(byte[] b,int nStart,int nLen) -!X\xA/KN  
{ x%55:8{  
int n = -1; =6[R,{|C  
try{ +uMK_ds~  
oSavedFile.write(b,nStart,nLen); }PzHtA,V  
n = nLen; _q`f5*Z[  
} hc]5f3Z  
catch(IOException e) F*=}}H/  
{ c6LPqPcN  
e.printStackTrace (); :YNXS;>)!  
} P*kC>lvSv  
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return n; 8:jakOeT  
} W+#Zmvo  
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e# KP3Lp  
} W"1=K]B  
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/* 2UEjn>2  
**SiteInfoBean.java 9~}.f1z  
*/ idNg&'   
package NetFox; 6Wc.iomx8  
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Ia-nA|LBxI  
public class SiteInfoBean { N683!wNX  
wE#z)2?`\  
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private String sSiteURL; //Site's URL I=&Kn
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private String sFilePath; //Saved File's Path ?9;r|G  
private String sFileName; //Saved File's Name a<&GsDw  
private int nSplitter; //Count of Splited Downloading File &U yQ<O>  
6G<gA>V  
jU=n\o=?  
public SiteInfoBean() HI{IC!6  
{//nSplitter的缺省值为5 '<&rMn  
//default value of nSplitter is 5 %#@5(_'  
this("","","",5); zN,2 (v"  
} z460a[Wl  
NSQ#\:3:S  
a<v!5\dq!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <CGJ:% AY  
{ yn.f?[G2  
sSiteURL= sURL; n^%",*8gD*  
sFilePath = sPath; JI|MR#_u  
sFileName = sName; !Bn,f2  
this.nSplitter = nSpiltter; br4 %(w(d  
;7N~d TBQ  
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} P6u%-#  
vABUUAo!Jr  
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public String getSSiteURL() ;BYv&(#u1q  
{ &HJ'//bv  
return sSiteURL; OQh4MN#$  
} c_FnJ_++f  
}TwSSF|}3  
?7R&=B1g  
public void setSSiteURL(String value) 03a<Cd/S  
{ 8d8GYTl b)  
sSiteURL = value; FlepM*  
} _?a.S8LxJZ  
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7q'T,'[  
public String getSFilePath() &KVXU0F^z  
{ {V5eHn9/Q'  
return sFilePath; pEX|zee  
} yf2$HF  
%2<u>=6byG  
wUcp_)aE|  
public void setSFilePath(String value) $gysy!2}.  
{ 29r(Y  
sFilePath = value; ;B6m;[M+  
}
v7G&`4~  
_e94  
]j57Gk%z  
public String getSFileName() Kld#C51X f  
{ nv_9Llh=z  
return sFileName; c,_??8  
} zE1=*zO`  
]]8^j='P
'  
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public void setSFileName(String value) i'`[dwfS  
{ QV9z81[  
sFileName = value; AQIBg9y7  
} _68{ {.  
gMUCVKGf  
=Bw2{]w  
public int getNSplitter() gPw{'7'
U  
{ g<PglRr"  
return nSplitter; &~sirxR p  
} 40Hm+Ge  
.l +yK-BZ  
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public void setNSplitter(int nCount) 'O[0oi&  
{ SCo;Ek  
nSplitter = nCount;
nV3I6  
} <T+{)FV  
} Ji7<UJ30x  
YK%rTbB(  
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/* DZqY=Sze  
**Utility.java !?5YXI,  
*/ {W$K@vuV;?  
package NetFox; <db>~@;X!  
@23~)uiZa  
OmLe+,7'  
public class Utility { `/JuItL-  
/a?qtRw  
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public Utility() 'ZAl7k .  
{ tZan1C%p>  
e"&QQ-q  
6o<(,\ad[  
} 5%RiM|+  
:s>x~t8g#n  
//线程睡眠 D-4{9[  
public static void sleep(int nSecond) 1:22y:^j  
{ '^%kTNn  
try{ .JX9(#Uk  
Thread.sleep(nSecond); !!d?o  
} RAj>{/E#W  
catch(Exception e) -Pc6W9$  
{ y3OF+;E  
e.printStackTrace (); v"-K-AQjB  
} hGJANA  
} t^~Qv  
K/M2L&C  
//日志 pT/z`o$#V  
public static void log(String sMsg) :f~qt%%/  
{ DB3qf>@?  
System.err.println(sMsg); ~3Y4_b5E  
} vwAtX($  
||4
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qyP={E9A  
public static void log(int sMsg) MI)v@_1d  
{ b_^y Ke^W  
System.err.println(sMsg); xJ9aFpTC  
} t~|J2*9l  
} &O#,"u/q`  
7 j6<  
1E
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/* Rqr
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**TestMethod.java Z)md]Twt  
*/ 'qJ0338d#U  
package NetFox; IKV!0-={!z  
1!NrndJI  
in6*3C4  
public class TestMethod { c(aykIVOo  
i` Q&5KL  
aa"3 Io  
public TestMethod() 1)5$,+~lL  
{ ///xx/weblogic60b2_win.exe N'i)s{'  
try{ Zz"8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %SuELm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b!bg sd  
SiteFileFetch fileFetch = new SiteFileFetch(bean); t YxN^VqU  
fileFetch.start(); nW}jTBu_K+  
} LosRjvQ:  
catch(Exception e){e.printStackTrace ();} X9ZHYlr+Q  
}x+6<Rp'E_  
V>/,&~0  
} x"!`JDsS  
@dx8{oQ  
4}s'xMT!  
public static void main(String[] args) U
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{ x-]:g&5T  
new TestMethod(); *<X1M~p$  
} @<`V q  
} Q-rG~O9-  
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