http断点续传简单实现（java)

/* GlOSCJZ  
**SiteFileFetch.java ^Z>Nbzr{  
*/ gWGh:.
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package NetFox; W @]t  
import java.io.*; 8#ZF<BY  
import java.net.*;
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public class SiteFileFetch extends Thread { v\G+t2{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean o^3X5})sv  
long[] nStartPos; //开始位置 v/GZByco>  
long[] nEndPos; //结束位置 1EHL8@.M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "KKw\
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long nFileLength; //文件长度 O"ebrv  
boolean bFirst = true; //是否第一次取文件 >|rU*+I`  
boolean bStop = false; //停止标志 V'8Rz#Gc5  
File tmpFile; //文件下载的临时信息 7m.>2U  
DataOutputStream output; //输出到文件的输出流 3{{Ew}kZm  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） VT2f\d[Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException mIW/x/I  
{ pC/13|I  
siteInfoBean = bean; aXgngwq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .YlhK=d4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _W  
if(tmpFile.exists ()) oqa8v6yG'  
{ 0]Qk*u<  
bFirst = false; 7srq~;j3  
read_nPos(); gXvE^fE  
} HXb_k1n  
else R*l3 zn>  
{ 1'!%$D  
nStartPos = new long[bean.getNSplitter()]; Lk]W?  
nEndPos = new long[bean.getNSplitter()]; 6FFM-9*|[  
} %fIYWu`X  
)
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} .W51Cup@&  
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public void run() )ml#2XP!f  
{ @y/!`Ziw  
//获得文件长度 'B;n&tJ   
//分割文件 Wg=qlux-  
//实例FileSplitterFetch giHqc7-PaX  
//启动FileSplitterFetch线程 * zc[t  
//等待子线程返回 <N8z<o4rku  
try{ F13vc~$Ky  
if(bFirst) ?D+H2[n\a  
{ w^^8*b<  
nFileLength = getFileSize(); srryVq
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if(nFileLength == -1) ]VoJ7LoCZ'  
{ "J{A}g[  
System.err.println("File Length is not known!"); [8'^"  
} zsr;37  
else if(nFileLength == -2) >9,LN;Ic
 
{ ,0aRHy_^  
System.err.println("File is not access!"); /pL'G`  
} jJV1 /]TJ  
else D77s3AyHK  
{ "eIE5h  
for(int i=0;i<nStartPos.length;i++) SedVp cb+  
{ +R',
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^+O97<#6C  
} XBm ^7'  
for(int i=0;i<nEndPos.length-1;i++) =}%Q}aPp  
{ y]}N[l  
nEndPos = nStartPos[i+1]; $msf~M*  
} 5s:g(gy3BR  
nEndPos[nEndPos.length-1] = nFileLength; -Yg?
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} [tkP2%1  
} BFQ`Ab+  
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+wcif-  
//启动子线程 Xb.# =R  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (!%w  
for(int i=0;i<nStartPos.length;i++) ]RxWypA`  
{ T/?C_
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3il/{bgM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), B:6VD /qC  
nStartPos,nEndPos,i); 0,wmEV!)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XnB-1{a1  
fileSplitterFetch.start(); 1"No~/_  
} I+rLKGZC  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H^JFPvEc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KeWIC,kq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ee^>Q*wahw  
nEndPos = " + nFileLength); jZ0/@zOf  
// fileSplitterFetch[nPos.length-1].start();
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=a6e*f  
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//等待子线程结束 #kp+e)F  
//int count = 0; o`.5NUn  
//是否结束while循环 %$F_oO7"  
boolean breakWhile = false; Bp/25jy  
 #zg"E<  
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while(!bStop) S"%W^)mZ  
{ 3-gy)5.xe  
write_nPos(); r#w.yg4EX  
Utility.sleep(500); 0}
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breakWhile = true; @;Xa&*  
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for(int i=0;i<nStartPos.length;i++) R) J/z  
{ Xz"xp8Hc(6  
if(!fileSplitterFetch.bDownOver) 2U) 0k*  
{ U98e=57N  
breakWhile = false; [s F/sa3  
break; Hd{@e6S  
} V eLGxc  
} iZ9ed]mf  
if(breakWhile)
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break; ddEV@2F  
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//count++; Dyh|F\T  
//if(count>4) ?pV!`vp^{  
// siteStop(); 
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} 0A F}wz>  
-_irkpdC[  
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System.err.println("文件下载结束！"); 3ZhuC".c  
} I~ e,']  
catch(Exception e){e.printStackTrace ();} b5W(}ka+  
} X{P=2h#g  
!fG}<6&i  
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//获得文件长度 8UXtIuQ  
public long getFileSize() M9KoQS  
{ H
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int nFileLength = -1; VVk8z6W  
try{ MGsY3~!K  
URL url = new URL(siteInfoBean.getSSiteURL()); S&NWZ:E3[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); newURb,-!  
httpConnection.setRequestProperty("User-Agent","NetFox"); &e99P{\D  
!rff/0/x"  
40
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int responseCode=httpConnection.getResponseCode(); j7b4wH\#  
if(responseCode>=400) Xn%O .yM6  
{ {=9"WN
 
processErrorCode(responseCode); (1Klj+"p%  
return -2; //-2 represent access is error ->2m/d4a  
} 7,FhKTV1/  
9/dADJe0b  
 e,T^
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String sHeader; 6b\JD.r*{  
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for(int i=1;;i++) ;-8]  
{ $tDM U3,W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yw*| HT  
//Utility.log(in.readLine()); Y/y`c-VO  
sHeader=httpConnection.getHeaderFieldKey(i); z|O3pQn~  
if(sHeader!=null) yo :63CPP  
{ F-GH
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if(sHeader.equals("Content-Length")) [m(n-MuF  
{ 6@I
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); B4x@{rtER  
break; d bHxc@H  
} L4v26*P  
} J6Nhpzp  
else a'?V:3 ]  
break; !H~PF*,hY  
} bOD]`*q  
} hZ-?-F?*@  
catch(IOException e){e.printStackTrace ();} sU"sd7#A  
catch(Exception e){e.printStackTrace ();} ~$m:j];  
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Utility.log(nFileLength); EC7)M}H  
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return nFileLength; VUzRA"DP|  
} K,dEa<p  
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//保存下载信息（文件指针位置） ?s[!JeUA  
private void write_nPos() rbI 7 3'  
{ (BIg  
try{ TsY nsLQY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |J:m{  
output.writeInt(nStartPos.length); r)oR`\7  
for(int i=0;i<nStartPos.length;i++)  BF /4  
{ -V=,x3Zew  
// output.writeLong(nPos); r}-vOPn`E  
output.writeLong(fileSplitterFetch.nStartPos); smHQ'4x9  
output.writeLong(fileSplitterFetch.nEndPos); 1Sd<cOEd  
} pI( H7 (  
output.close(); - @tL]]  
} ;OSEMgB1  
catch(IOException e){e.printStackTrace ();} 7
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catch(Exception e){e.printStackTrace ();} 15R:m:T  
} WP !u3\91  
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(1)b> 6  
//读取保存的下载信息（文件指针位置） lF~!F<^9  
private void read_nPos() R/l/GNm  
{ hI,+J>  
try{ Vsd4;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =h[;'v{  
int nCount = input.readInt(); ?gG%FzfQ/  
nStartPos = new long[nCount]; $'COsiK7  
nEndPos = new long[nCount]; R{q<V uN  
for(int i=0;i<nStartPos.length;i++) wQojmmQ  
{ (/A 6kp?  
nStartPos = input.readLong(); `_(N(dm  
nEndPos = input.readLong(); gQuU_dbXSB  
} (8Te{Kh'  
input.close(); Gk!CU"`sP  
} pd.5  
catch(IOException e){e.printStackTrace ();} bpdluWS+)  
catch(Exception e){e.printStackTrace ();} rN`-ak  
} e5m]mzF@  
=4K:l}}  
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private void processErrorCode(int nErrorCode) M\r=i>(cu  
{ i:7cdhz  
System.err.println("Error Code : " + nErrorCode); Xw&vi\*m  
} QsyM[;\j:  
$>hH{  
ORFi0gFbA  
//停止文件下载 jm,:jkr  
public void siteStop() :
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{ 0iVeM!bM  
bStop = true; }[]1`2qD  
for(int i=0;i<nStartPos.length;i++) &;%,Axc  
fileSplitterFetch.splitterStop(); sn8r`59C  
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} =m U</F)  
} )5w#n1  
//负责部分文件的抓取 kcE86Y=|x!  
**FileSplitterFetch.java .B{:<;sa  
*/ f9^MLb6)  
package NetFox; z;\,
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jV(b?r)eT{  
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import java.io.*; +Oc |Oo  
import java.net.*; xOKf|  
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public class FileSplitterFetch extends Thread { ;9hS_%ldX4  
__[bKd.  
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String sURL; //File URL % E8s>D  
long nStartPos; //File Snippet Start Position V@\A<q%jTs  
long nEndPos; //File Snippet End Position 9a]h;r8,9z  
int nThreadID; //Thread's ID O[z-K K<  
boolean bDownOver = false; //Downing is over 3#Xv))w1  
boolean bStop = false; //Stop identical #ib?6=s
PC  
FileAccessI fileAccessI = null; //File Access interface cCqmrjUmV  
G1ED=N_#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x{1S!A^  
{ tW%!|T5/  
this.sURL = sURL; 6{H@VF<QY!  
this.nStartPos = nStart; MsP`w3b
 
this.nEndPos = nEnd; S&MF; E6  
nThreadID = id; bH.f4-.u>)  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fn Pej?f:  
} M^0^l9w  
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public void run() .ViOf){U\  
{ =Iy khrS  
while(nStartPos < nEndPos && !bStop) XT{ukEvDR  
{ Mi7LyIu  
2]+f<Z[/  
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try{ .{"wliC2  
URL url = new URL(sURL); D}nIF7r2N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "(vm0@8><  
httpConnection.setRequestProperty("User-Agent","NetFox"); VIuzBmR|\  
String sProperty = "bytes="+nStartPos+"-"; .`/6[Zp

 
httpConnection.setRequestProperty("RANGE",sProperty); U^&y*gX1  
Utility.log(sProperty); '(SqHP|8&g  
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InputStream input = httpConnection.getInputStream(); y@Ak_]{b  
//logResponseHead(httpConnection); 2(2
5IYMS8  
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byte[] b = new byte[1024]; B0m2SUC,H  
int nRead; &cT@MV5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (`&E
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{ "$ep=h+  
nStartPos += fileAccessI.write(b,0,nRead); }=s64O9j  
//if(nThreadID == 1) \)2~oN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lj@ibA]  
} kw5`KfG9  
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Utility.log("Thread " + nThreadID + " is over!"); U\(T<WX,  
bDownOver = true; =o_zsDv  
//nPos = fileAccessI.write (b,0,nRead); zUz j F  
} %dq|)r  
catch(Exception e){e.printStackTrace ();} *q0vp^?  
} T49^  
} 5`{u! QE  
xk&#fW^r  
#BhcW"@  
//打印回应的头信息 E/3<8cV  
public void logResponseHead(HttpURLConnection con) u*8x.UE8C0  
{ /`b`ai8`8  
for(int i=1;;i++) PbY=?>0z  
{ \Z$MH`_nu  
String header=con.getHeaderFieldKey(i); 1_5]3+r_U-  
if(header!=null) b}Wm-]|+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); XWBTBL  
Utility.log(header+" : "+con.getHeaderField(header)); 4[ =C,5r  
else ^%}PRl9  
break; G(MLq"R6U  
} ApqNV  
} diD[/&k#kh  
$DhW=(YM_a  
{@ Z%6%'9  
public void splitterStop() *&$2us0%%  
{ b2UqN]{  
bStop = true; JjnWv7W3$  
} >JT^[i8[  
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} <L:}u!  
v6O5n(5,,  
'rSJ9Mw"x  
/*    
**FileAccess.java nD#uOep9  
*//文件访问(定位，写) _TjRvILC  
package NetFox; G!g];7PG(  
import java.io.*; `_ )5K u}  
A9ZK :i7  
/e]R0NI  
public class FileAccessI implements Serializable{ :p.f zL6X  
V7$-4%NL  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c!J|vRA5  
RandomAccessFile oSavedFile; -Rj3cx  
long nPos; F tay8m@f  
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public FileAccessI() throws IOException ?T_bjALW  
{ +"JQ5~7  
this("",0); 8W}rSv+  
} Hzojv<c  
I
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public FileAccessI(String sName,long nPos) throws IOException =$
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{ 7x)32f"  
oSavedFile = new RandomAccessFile(sName,"rw"); X oh@(%  
this.nPos = nPos; $fQ'q3  
oSavedFile.seek(nPos); =7Sw29u<  
} k;pU8y6Y  
{/K!cPp9  
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public synchronized int write(byte[] b,int nStart,int nLen) RKwuvVI  
{ e/F+Tf  
int n = -1; zd?uMq;w  
try{ )KcY<K  
oSavedFile.write(b,nStart,nLen); Zr$D\(hX  
n = nLen; /[UuHU5*R  
} #gRtCoew  
catch(IOException e) .MW/XnCYs4  
{ ]QmY`pT
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e.printStackTrace (); 1owe'7\J  
} Ct386j><  
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return n; ~uh,R-Q$  
} >^Y)@J
 
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} K"g`,G6S  
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!=(M
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/* . /~#  
**SiteInfoBean.java qaEWK0  
*/ js)I%Z  
package NetFox; {z7kW@c  
a'B 5m]%  
./Wi(p{F  
public class SiteInfoBean { <*5`TE0J  
yI8 /m|  
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private String sSiteURL; //Site's URL T*zy^we  
private String sFilePath; //Saved File's Path yrV]I(Xe  
private String sFileName; //Saved File's Name bXK$H=S Bz  
private int nSplitter; //Count of Splited Downloading File 2hE+Om^n  
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public SiteInfoBean() x*0mmlCb  
{//nSplitter的缺省值为5 0j2M< W#  
//default value of nSplitter is 5 lv\^@9r  
this("","","",5); 'cvc\=p  
} 6|ENDd[  
l&
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G?v]|wdI  
{  q{RT~,%  
sSiteURL= sURL; o3>D~9  
sFilePath = sPath; CUa`#  
sFileName = sName; 6cbIs_g  
this.nSplitter = nSpiltter; -mqTlXM  
CB>O%m[1  
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} 02~GT_)$^  
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MI*@^{G  
public String getSSiteURL() T.iVY5^<  
{ BxHfL8$1[$  
return sSiteURL; mY/x|)MmM  
} #GA6vJ4^s  
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~
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public void setSSiteURL(String value) vAo|o*  
{ @BS7Gyw  
sSiteURL = value; 6+x>g  
} .DZ8kKY  
y2NVx!?n  
Dp" xO<PE2  
public String getSFilePath() eHHqm^1z  
{ (vr v-4  
return sFilePath; C}cYG  
} zqAp7:  
F)4;:".zna  
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public void setSFilePath(String value) h,)UB1  
{ n%}Vd `c  
sFilePath = value; _,5)  
} ?)'+l   
=%$BFg1a(  
p_l.a  
public String getSFileName() bAm ,gP  
{ YlEV@  
return sFileName; `KzNBH,W  
} C9}m-N  
rdQ'#}Ix  
h?`'%m?_b  
public void setSFileName(String value) "ba>.h,#'  
{ Xw{Qktn  
sFileName = value; %[7<GcWl  
} WbDD9ZS  
E
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L$<(HQQJ8  
public int getNSplitter() g;PZ$|%&s>  
{ +q@g  
return nSplitter; C4/p5J  
} 34Z$a{ w  
8f{;oO  
\' ;zD-MX  
public void setNSplitter(int nCount) GJIM^  
{ gCc::[}\Y  
nSplitter = nCount; FV W&)-I  
} S#l6=zI7^R  
} 0xe*\CAo  
lpHz*NZ0  
u&s>UkR  
/* GK-__Y.  
**Utility.java SY
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*/ k>dzeH  
package NetFox; )A H)*Mg  
2%zJI"Ic  
2v9T&xo=  
public class Utility { cpg+-Zf%  
Af{K#R8!  
!$|h[ct  
public Utility() ;L.RfP"5<  
{ !w-`:d?  
YR} P;  
@&LtIN#  
} -Rz%<`  
biw2f~V  
//线程睡眠 g_F-PT>($  
public static void sleep(int nSecond) *^b<CZd9  
{ ;fnE"}  
try{ "=ogO/_Q"  
Thread.sleep(nSecond); li~#6$  
} { WW!P,w  
catch(Exception e) 3D/<R|p  
{ FR9*WI   
e.printStackTrace (); U6Ws#e  
} <>|/U`  
} &H<n76G  
T)"LuC#C
 
//日志 mbh;oX+  
public static void log(String sMsg) o$,Dh?l  
{ <fm0B3i?  
System.err.println(sMsg); ]iL>Zxex  
} *dE5yS`H  
:UdH}u!Ek  
YoEL|r|  
public static void log(int sMsg) L-\o zp  
{ 1ZK~i  
System.err.println(sMsg); BPkqC>w  
} `lA[-x~  
} / %:%la%  
5EqC.g.  
.8K ~ h  
/* ~\~K
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**TestMethod.java mrvPzoF,]  
*/ V)g{ Ew]:  
package NetFox; 9?~K"+-SI  
s$ v<p(yl  
"P_PqM  
public class TestMethod { G)'(%rl  
;$= GrR  
2%F!aeX  
public TestMethod() N)H _4L  
{ ///xx/weblogic60b2_win.exe ek3,ss3  
try{ ^w*$qzESy  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ehCZhi~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); uk)6%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =
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fileFetch.start(); Sd0y=!Pj=  
} v%6mH6V  
catch(Exception e){e.printStackTrace ();} gQ@fe3[  
[hT|]|fJS;  
o/Cu^[an  
} -WX{y Ci  
?6[X=GeUs  
L% cr`<~  
public static void main(String[] args) nB+ e2e&  
{ OG&X7>'3I{  
new TestMethod(); .oR_r1\y  
} `LID*uD;_  
} R?K[O   
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