http断点续传简单实现（java)

/* UQji7K }  
**SiteFileFetch.java +}G>M=t::  
*/ |$|nV^y  
package NetFox; *2m&?,nJ  
import java.io.*; t#D\*:Xi  
import java.net.*; 7zP  
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public class SiteFileFetch extends Thread { c J"]yG)=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ;ijfI  
long[] nStartPos; //开始位置 \ \mO+N47i  
long[] nEndPos; //结束位置 \'^Z_6{w  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Med"dHo7  
long nFileLength; //文件长度 ss*2TE7  
boolean bFirst = true; //是否第一次取文件 *V@MAt  
boolean bStop = false; //停止标志 g9lg  
File tmpFile; //文件下载的临时信息 H{tOCYyD  
DataOutputStream output; //输出到文件的输出流 g!kRa.`u1  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2G:{FY  
public SiteFileFetch(SiteInfoBean bean) throws IOException $RF
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{ Fp|rMq
 
siteInfoBean = bean; uTlT'9)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Bdk{.oh6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); E6^S2J2  
if(tmpFile.exists ()) ;~1/eF  
{ @Ozf}}#  
bFirst = false; yV]-Oa$*s0  
read_nPos(); YT 03>!B  
} '`goy%Wd  
else CK`3   
{ WbDC  
nStartPos = new long[bean.getNSplitter()]; ofrlTw&o  
nEndPos = new long[bean.getNSplitter()]; $d??(  
} )i6U$,]  
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} CR<pB)F?a  
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public void run() sxQ,x/O  
{ 7!yF5+_d  
//获得文件长度 _ L:w;Oy9T  
//分割文件 my\oC^/9  
//实例FileSplitterFetch hr}R,BR|  
//启动FileSplitterFetch线程 Ef*.}gcU  
//等待子线程返回 3L!&~'.Ro  
try{ nTtt$I@hW  
if(bFirst) yI|?iBc7nC  
{ vheAh`u^&  
nFileLength = getFileSize(); ) ImIPSL  
if(nFileLength == -1) q2U"k  
{ R\Ynn^w  
System.err.println("File Length is not known!"); ?yM/j7Xn  
} 2'^OtM,  
else if(nFileLength == -2) i$Zpo
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{ [t=+$pf(-  
System.err.println("File is not access!"); ;51!aC  
} u$/2XO  
else czsoD)N  
{ SF
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for(int i=0;i<nStartPos.length;i++) /t6u"I~  
{ 8RT0&[  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} ps;o[gB@5  
for(int i=0;i<nEndPos.length-1;i++) G@I_6cE  
{ T^H) lC#R  
nEndPos = nStartPos[i+1]; Xqva&/-  
} J1ro
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nEndPos[nEndPos.length-1] = nFileLength; 1#_j6Q2  
} nz?BLO=  
} C%o/  
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L$?~TY  
//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7ofH@U  
for(int i=0;i<nStartPos.length;i++) \^W?  
{ (']z\4o  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ph'SS=!.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), a|{<#<6n(  
nStartPos,nEndPos,i); k.R/X  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZZJ"Ny.2  
fileSplitterFetch.start(); YZtA:>;p  
} ZTz(NS EK  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x3F L/^S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #K*q(ei,7h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", QS?9&+JM|  
nEndPos = " + nFileLength);
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// fileSplitterFetch[nPos.length-1].start(); [goPmVe+  
|BWK"G  
H9m2Whq  
//等待子线程结束 X10TZ  
//int count = 0; <1%XN  
//是否结束while循环 $[;eb,  
boolean breakWhile = false; ;j\$[4W.i  
~(P\F&A(&  
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while(!bStop) ?Lb7~XKt\  
{ Ps5wQaS  
write_nPos(); a9JJuSRC  
Utility.sleep(500); Vk=<,<BB  
breakWhile = true; Vx8.FNJh  
}nERQq&A  
XzFqQ-H  
for(int i=0;i<nStartPos.length;i++) @?AE75E{  
{ X \ZUt >  
if(!fileSplitterFetch.bDownOver) _^$b$4)  
{ 7#*CWh1BNO  
breakWhile = false; .ihn@eg  
break; I,Y^_(JW  
} z9c=e46O  
} *"L:"i`*$  
if(breakWhile) zq>"a&Y,  
break; (MU7  
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D4S?bZFHo  
//count++; 6>7LFV1tvy  
//if(count>4) <[??\YOc  
// siteStop(); j?ubh{Izm  
} 9 f/tNQ7W  
e';c8WF3E  
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System.err.println("文件下载结束！"); f3|=T8"t  
} Q#bo!]H{t  
catch(Exception e){e.printStackTrace ();} 2_DtzY:=  
} Q*o4zW  
}+Z;zm@/6  
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//获得文件长度 &,|uTIs  
public long getFileSize() 9:5NX3"p  
{ UZ0O j5B.  
int nFileLength = -1; 3+PM_c)Y  
try{ OtqLigt&l  
URL url = new URL(siteInfoBean.getSSiteURL()); !-Q!/
?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {D
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httpConnection.setRequestProperty("User-Agent","NetFox"); ;8kfgpM_  
@}RyW&1Z  
o
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int responseCode=httpConnection.getResponseCode(); #?|z&
9  
if(responseCode>=400) 3{E}^ve  
{ S8<aq P  
processErrorCode(responseCode); \"j1fAD!  
return -2; //-2 represent access is error }('QIvq2  
} RtEkd_2  
l'R`XGT  
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String sHeader; (jMp`4P  
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for(int i=1;;i++) c(JO;=,@9  
{ GoXHVUyp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z)~4)71Y:  
//Utility.log(in.readLine()); D]_\i[x  
sHeader=httpConnection.getHeaderFieldKey(i); {(Z1Jo
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if(sHeader!=null) EFOQ;q  
{  .l'QCW9  
if(sHeader.equals("Content-Length")) `/iN%ZKum  
{ RH'R6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J#nEGl|a  
break; $o^}<)DW  
} B-zt(HG  
} L1+cv;t  
else 6P$q7G  
break; 8b $7#  
} .=D6<4#t  
} :v48y.Ij7s  
catch(IOException e){e.printStackTrace ();} ;W:Q}[  
catch(Exception e){e.printStackTrace ();} 7%WI  
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Vt>E\{@[t  
Utility.log(nFileLength); (ZJ_&8C#  
> [7vXm4  
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return nFileLength; CiFbk&-g  
} 8i"fhN3?Y  
Rh^$0Q*2  
2|EoP-K7  
//保存下载信息（文件指针位置） ]e9kf$'  
private void write_nPos() I}{eYXh  
{ 0U~JSmj:2K  
try{ ]|(?i ,p  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <9vkiEo  
output.writeInt(nStartPos.length); y3GIR f
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for(int i=0;i<nStartPos.length;i++) !Zx>)V6.  
{ ~a Rq\fx{  
// output.writeLong(nPos); W3kilhZ  
output.writeLong(fileSplitterFetch.nStartPos); =#Jb9=zdR  
output.writeLong(fileSplitterFetch.nEndPos); ,kI1"@Tu  
} m-]"I8[  
output.close(); i
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} Z m>69gl  
catch(IOException e){e.printStackTrace ();} a!.8^:B&  
catch(Exception e){e.printStackTrace ();} F.9|$g*ip  
} kM@,^`&  
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//读取保存的下载信息（文件指针位置） HC$cK+,ZU}  
private void read_nPos() 7va%-&.&t  
{ _9dV 3I  
try{ Adm`s .  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9`{cX  
int nCount = input.readInt(); 'rgV]Oy  
nStartPos = new long[nCount]; rL
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nEndPos = new long[nCount]; 9:WKG'E8a  
for(int i=0;i<nStartPos.length;i++) Ig2VJs;  
{ [;bLlS,  
nStartPos = input.readLong(); |ipppE=  
nEndPos = input.readLong(); _4w%U[GT,  
} 'tj4;+xf^  
input.close(); IG\\RYr  
} 6W o7q\"  
catch(IOException e){e.printStackTrace ();} ubw ]}sfM#  
catch(Exception e){e.printStackTrace ();} MmB-SR[>P  
} >Ww F0W9?  
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private void processErrorCode(int nErrorCode) rkrt.B  
{ !.A>)+AK  
System.err.println("Error Code : " + nErrorCode); g$qh(Z_s  
} c4|.!AQ>  
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H+Wd#7l,  
//停止文件下载 .0 K8h:I  
public void siteStop() \v<}{\.|$  
{ R:E:Y|&#  
bStop = true; e# DAa  
for(int i=0;i<nStartPos.length;i++) gYZgo  
fileSplitterFetch.splitterStop(); xHmc8G$zu  
? "gy`oCv  
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} 6)8']f  
} +}!eAMQ  
//负责部分文件的抓取 $i hIHl6'  
**FileSplitterFetch.java C%&7,F7  
*/ ))Nc|`  
package NetFox; 0#ph1a<  
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import java.io.*; w K+2;*bI  
import java.net.*; =W6P>r_  
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public class FileSplitterFetch extends Thread { mTt 9 o9E  
b({2|R  
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String sURL; //File URL Zo`^pQS  
long nStartPos; //File Snippet Start Position )xeVoAg  
long nEndPos; //File Snippet End Position t t=$:}A  
int nThreadID; //Thread's ID t%%I.zIV7  
boolean bDownOver = false; //Downing is over (
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boolean bStop = false; //Stop identical lZ|
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FileAccessI fileAccessI = null; //File Access interface &xVWN>bd^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6\`,blkX  
{ c:bB4ch}  
this.sURL = sURL; s}.nh>Q  
this.nStartPos = nStart; AxeWj%w@  
this.nEndPos = nEnd; >/>a++19  
nThreadID = id; p81~Lk*Hz@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 JBqzQ^[n  
} R#t~i&v/  
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public void run() P_;oSN|>  
{ LZeR.8XM>  
while(nStartPos < nEndPos && !bStop) )gR&Ms4  
{ $KiA~l  
{|fA{ Q_R  
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try{ q&+GpR  
URL url = new URL(sURL); HTC7fS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I|.B-$gH  
httpConnection.setRequestProperty("User-Agent","NetFox"); V3-LVgM%  
String sProperty = "bytes="+nStartPos+"-"; a'|0e]  
httpConnection.setRequestProperty("RANGE",sProperty); k;)L-ge9  
Utility.log(sProperty); 1ayxE(vMcX  
i-Z@6\/a5  
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InputStream input = httpConnection.getInputStream(); cc>h=%s`  
//logResponseHead(httpConnection); -{O2Nv-]]  
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byte[] b = new byte[1024]; &,\S<B2.  
int nRead; U;^{uQJ+,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3RD Q{
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{ .RT5sj\d  
nStartPos += fileAccessI.write(b,0,nRead); {>i'Pb0mG|  
//if(nThreadID == 1) v4&*iT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5W'T7asOh  
} R_^:<F0  
:( `Q4D~l  
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Utility.log("Thread " + nThreadID + " is over!"); k~?@~xm,R  
bDownOver = true; @a~K#Bvlm  
//nPos = fileAccessI.write (b,0,nRead); h_cZ&P|  
} wC[J=:]tA5  
catch(Exception e){e.printStackTrace ();} -0W;b"]+A  
} +n0y/
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} SZgH0W("L  
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{30A1>0#P  
//打印回应的头信息 ^Ab|\5^3  
public void logResponseHead(HttpURLConnection con) Oz+>I^Q  
{ ]!f=b\-Av  
for(int i=1;;i++) _K9jj  
{ /g_}5s-Z  
String header=con.getHeaderFieldKey(i); rsP1?Hxq  
if(header!=null) uto4bs:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Kp"o0fh<9  
Utility.log(header+" : "+con.getHeaderField(header)); OaEOk57%de  
else hWUZn``U$|  
break; #bGt%*Re p  
} SDot0`s>  
} Uzc`,iV$  
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public void splitterStop() -JcfP+{wS  
{ /JvNJ f  
bStop = true; kY*D
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} Pp}j=$&j\  
k:c)|2  
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} P'g$F<~V  
!#>{..}}3  
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/* 3D\I#g  
**FileAccess.java lc*<UZR  
*//文件访问(定位，写) ?gTY!;$P  
package NetFox; 3.8d"  
import java.io.*; [1N*mY;  
2r1.,1  
W#ev  
public class FileAccessI implements Serializable{ VPf=LSxJe  
HQ]g{JVld\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7ZN0_Qs  
RandomAccessFile oSavedFile; !"_\5$5i<X  
long nPos; x;kW }U  
O7E0{8  
/Wt<[g#  
public FileAccessI() throws IOException H1N%uk=kV  
{ rR/PnVup  
this("",0); >R :Bkf-  
} O[$&]>x]]  
8E|S`I  
"/wZtc  
public FileAccessI(String sName,long nPos) throws IOException ~ZT(@w  
{ 1{_;`V  
oSavedFile = new RandomAccessFile(sName,"rw"); 6VIi nuOW  
this.nPos = nPos;  d':c  
oSavedFile.seek(nPos); |o6B:NH,rg  
} 58WL8xu  
?&"-y)FG  
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public synchronized int write(byte[] b,int nStart,int nLen) \=i>}Sg  
{ @*!8  
int n = -1; ?oP<sGp  
try{  z7>  
oSavedFile.write(b,nStart,nLen); U@DIO/C,m`  
n = nLen; H htAD Y  
} %I?uO( @  
catch(IOException e) :H3qa2p  
{ @=:( b"Sg  
e.printStackTrace (); V D-,)f  
} [$f  
Bh<)e5lP:  
6/ F]ncwG  
return n; aNw8][  
} Y=\;$:L[  
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} n-0RA~5z  
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/* &E0P`F,GQA  
**SiteInfoBean.java yKgA"NaM  
*/ |cUTP!iy  
package NetFox; N"@aisi)  
yMB*/vs  
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public class SiteInfoBean { !-)Hog5\  
9+_SG/@  
-ich N/U]s  
private String sSiteURL; //Site's URL gWL'Fl}H  
private String sFilePath; //Saved File's Path ]+Ik/+Nz  
private String sFileName; //Saved File's Name N8_ c%6GE  
private int nSplitter; //Count of Splited Downloading File rK7m(  
4:WN-[xX  
3%p^>D\  
public SiteInfoBean() 4At{(fwW  
{//nSplitter的缺省值为5 |Q[[WHqj2f  
//default value of nSplitter is 5 XcD$xFDZ  
this("","","",5); #|ETH;HM  
} 3]$qY_|7  
+O8rjVg)  
2= S;<J
 
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Db3#;  
{ \("|X>00  
sSiteURL= sURL; C5"=%v[gQv  
sFilePath = sPath; R9xhO!  
sFileName = sName; #0GvL=}k  
this.nSplitter = nSpiltter; 6
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} D;*P'%_Z  
L"e8S%UqX  
Te_%r9P|2  
public String getSSiteURL() 'So,*>]63  
{ VB=$D|Ll  
return sSiteURL; #6* j+SX^  
} %PW_v~sg  
2)cq!Zv  
]6#bp,  
public void setSSiteURL(String value) HtFc+%=  
{ wA$ JDf)Vg  
sSiteURL = value; jJc:%h$|2  
} |soDt<y+L  
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public String getSFilePath() 6
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{ ,sF49CD  
return sFilePath; l=4lhFG,Mk  
} 8725ET t  
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_3YZz$07  
public void setSFilePath(String value) jjLx60|{  
{ _ x8gEK8  
sFilePath = value; g4z*6L,u  
} `-yo-59E[  
Fp=O:]  
!79eF)  
public String getSFileName() -9)H[}.  
{ :Q]P=-Y8  
return sFileName; $DS|jnpV  
} (t[sSl  
-,YoVB!T  
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public void setSFileName(String value) xNAX)v3Z  
{ we?
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sFileName = value; ,v\^efc:%  
} gZ!q  
JO[7_*s  
/hF@Xh%hY  
public int getNSplitter() FqwH:Fcr:  
{ K)DpC*j  
return nSplitter; J> Z.2  
} !pTi.3  
 VB&`S+-  
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public void setNSplitter(int nCount) o|`%>&jP  
{ sH_B*cr3  
nSplitter = nCount; ?2q4dx0  
} >8;EeRvI  
} >>nOS]UL  
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r{mj[N'@  
/* kD*r@s]=  
**Utility.java ?q{HS&k  
*/ %H/V iC  
package NetFox; u7(<
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-}x( MZ  
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public class Utility { ! mb<z^>5  
^jYE4gHM  
Q
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public Utility() ks19e>'5Q  
{ (pv6V2i  
}z,f8Yz  
,azBk`$iQr  
} ;X;q8J^_K_  
{J~VB~('  
//线程睡眠 OrPi ("/  
public static void sleep(int nSecond) BWF>;*Xro  
{ !FA[ ]d4  
try{ ;M<R e  
Thread.sleep(nSecond); 3sD/4 ?  
} nVyV]'-z  
catch(Exception e) nG4}8  
{ ,II-:&H  
e.printStackTrace (); W!Fu7a  
}
taBCE?{  
} ihp>cl?  
/< -+*79G  
//日志 Ja
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public static void log(String sMsg) N!lQ;o'  
{ Wj INY  
System.err.println(sMsg); s:zz8oN  
} 5}Z_A?gy  
6<SX%Bc~  
2 Q}^<^r  
public static void log(int sMsg) ]5a,%*f+  
{ 9M;k(B!  
System.err.println(sMsg); 2A&Y})D  
} 8," 5z_  
} B%(-UTQf  
| Kw}S/F  
M$Or|HT
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/* 9v3%a3  
**TestMethod.java 0zc~!r~  
*/ <wTD}.n  
package NetFox; *f-8egt-  
]k)h<)nY  
v43FU3  
public class TestMethod { (|dN6M-.K  
UFPSQ  
Z/oP?2/Afh  
public TestMethod() WH lvd  
{ ///xx/weblogic60b2_win.exe ana?;NvC  
try{ jM[]Uh  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); uRnSwJ"hE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !n3J6%b9y/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); FA$1&Fu3Y  
fileFetch.start(); d)1Pl3+  
} jrN"en  
catch(Exception e){e.printStackTrace ();} B&Iy_;  
k)TNmpL%"  
|5g1D^b]s^  
} o2_mcJ  
"t&_!Rm  
oi\e[qE  
public static void main(String[] args) QHPC?a6CD  
{ !Ct'H1J-  
new TestMethod(); 94'0X  
} D:#e;K  
} ' }T6dS  
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