http断点续传简单实现（java)

/* th90O|;  
**SiteFileFetch.java d~,n_E$q;  
*/ d>~`j8,B  
package NetFox; e~*S4dKR  
import java.io.*; Ss+F9J  
import java.net.*; LiF.w:
}  
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public class SiteFileFetch extends Thread { BMF3XcH~G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean J:[3;Z  
long[] nStartPos; //开始位置 @NBXyC8,Z  
long[] nEndPos; //结束位置 E~qK&7+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Upu%.[7  
long nFileLength; //文件长度 /:^tc/5U]  
boolean bFirst = true; //是否第一次取文件 h4hd<,  
boolean bStop = false; //停止标志 s7AI:Zv  
File tmpFile; //文件下载的临时信息 ?;/{rITP#  
DataOutputStream output; //输出到文件的输出流 {6DpPw^"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `}ZL'\G  
public SiteFileFetch(SiteInfoBean bean) throws IOException |})rt5|f1!  
{ ruWye1X;  
siteInfoBean = bean; w zdxw$E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z^"?sd  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $/os{tzjd  
if(tmpFile.exists ()) &9k"9  
{ m/cx|b3hqv  
bFirst = false;
l; */M.B  
read_nPos(); B piEAwh  
} S[ i$e  
else \:C%> .VG  
{ xvHOY:  
nStartPos = new long[bean.getNSplitter()]; "_Zh5 g  
nEndPos = new long[bean.getNSplitter()]; mJ/^BT]  
} QK,=5~IJ  
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} '\4c "Ho  
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public void run() 5BZ+b_A>VV  
{ EwC5[bRjUp  
//获得文件长度 }`?7\\6  
//分割文件 JHHb|  
//实例FileSplitterFetch #V,LNX)  
//启动FileSplitterFetch线程 9{T 8M  
//等待子线程返回 E`U&Z  
try{ u87=q^$  
if(bFirst) rGGS]^  
{ uT#Acg  
nFileLength = getFileSize(); oXvdR(Sb^  
if(nFileLength == -1) ik8|9m4/  
{ 9$n+-GSK  
System.err.println("File Length is not known!"); 7O]J^H+7  
} Q=dw 6  
else if(nFileLength == -2) oA5<[&~<  
{ -wJ  
System.err.println("File is not access!"); ccIDMJ=2
 
} 6hR^qdHg  
else '3IkPy1Uz  
{ Cln^1N0  
for(int i=0;i<nStartPos.length;i++) <aD'$(N5  
{ jt0H5-x  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); pW`ntE#L  
} xzuPie\  
for(int i=0;i<nEndPos.length-1;i++) gF$1wV]e  
{ !k4 }v'=  
nEndPos = nStartPos[i+1]; AEiWL.*.  
} i/l!Cr2  
nEndPos[nEndPos.length-1] = nFileLength; Pm;x]Aj  
} -9hp+0 <  
} Zb12:?  
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//启动子线程 "6 uTo0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ee4KMS  
for(int i=0;i<nStartPos.length;i++) nNkyOaK*4  
{ :Bdipc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @&/s~3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3U :YA&K(  
nStartPos,nEndPos,i); `NYF?%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7Y$4MMNQ  
fileSplitterFetch.start(); u<BHf@AI  
} ay!6T`U`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <L[T'ZE+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yBUZVqqDa  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", r@N39O*Wq  
nEndPos = " + nFileLength); LG"BfYy6  
// fileSplitterFetch[nPos.length-1].start(); ,AGM?&A  
hpd(d$j  
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//等待子线程结束 Uqb
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//int count = 0; g6x/f<2x  
//是否结束while循环 S,ouj;B  
boolean breakWhile = false; F(?Fz8  
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while(!bStop) n23%[#,r  
{
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write_nPos(); 3:l:~Vn  
Utility.sleep(500); 5?#OR!N  
breakWhile = true; xMO[3D&D  
g] 7{5  
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for(int i=0;i<nStartPos.length;i++) vWPM:1A  
{ 'Qp&,xK  
if(!fileSplitterFetch.bDownOver) 2tg/S=t}  
{ GqmDDL1  
breakWhile = false; N2+mN0k;  
break; D;16}D  
} p 02nd.R6  
} f}evw K[S  
if(breakWhile) F:[Nw#gj/  
break; ^VM"!O;h{  
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s= -
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//count++; i} NkHEK  
//if(count>4) E< io^  
// siteStop(); Mo:!jS~a(Z  
} E-BOIy,  
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System.err.println("文件下载结束！"); Pl>nd)i`  
} d=xI   
catch(Exception e){e.printStackTrace ();} ;L\!g%a  
} {Oc?C:aI=  
t(uB66(_F  
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//获得文件长度 '/gxjr&  
public long getFileSize() #'G7mAoA  
{ 2yi*eR  
int nFileLength = -1; BJ:E,P`_  
try{ 2ZTyo7P  
URL url = new URL(siteInfoBean.getSSiteURL()); #Of<1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #2ZrdD"5kQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;:8jxkx6%  
e$p1Th*|]4  
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int responseCode=httpConnection.getResponseCode(); JWUv H  
if(responseCode>=400) }QApeZd+q  
{ !"o1ve`{  
processErrorCode(responseCode); W[jW;uk  
return -2; //-2 represent access is error +Zty}fe  
} kG|>_5  
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5W:Gl?$S}  
String sHeader; sTYuwna~   
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for(int i=1;;i++) lyOrM7Gs  
{ y<'2BTf  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bSeL"   
//Utility.log(in.readLine()); $Nt]${0  
sHeader=httpConnection.getHeaderFieldKey(i); #C=L^cSx(  
if(sHeader!=null) 2S7H_
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{ m\}\RnZu  
if(sHeader.equals("Content-Length")) =oKPMmpCZ  
{ <Vr]2mw  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); lhIr]'?l  
break; Gr"2G,,VI  
} wFoR,oXtL/  
} U#FJ8CD&u  
else LzEE]i  
break; fO^EMy\  
} .eDxIWW+ft  
} rt\<nwc  
catch(IOException e){e.printStackTrace ();} l+3%%TV@L  
catch(Exception e){e.printStackTrace ();} &a2V-|G',  
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Utility.log(nFileLength); UmP?}Xw6  
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return nFileLength; Is*0?9qU  
} j.yr5%  
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8
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//保存下载信息（文件指针位置） 6
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private void write_nPos() ,uqbS  
{ +=29y@c  
try{ Tr}$Pb1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NNREt:+kr  
output.writeInt(nStartPos.length); g^<q L|  
for(int i=0;i<nStartPos.length;i++) ke;*uS  
{ d= T9mj.@  
// output.writeLong(nPos); ]= QCCC  
output.writeLong(fileSplitterFetch.nStartPos); +_|cZlQ&  
output.writeLong(fileSplitterFetch.nEndPos); |0vHy7CE  
} [#3Cg%V  
output.close(); ~:RDw<PWp  
} mG8  
catch(IOException e){e.printStackTrace ();}  qzU2H  
catch(Exception e){e.printStackTrace ();} ;Cp/2A}Xx  
} [2H(yLwO  
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4[f7X4d$  
//读取保存的下载信息（文件指针位置） MkV*+LXC  
private void read_nPos() Y$`hudJ&  
{ dO4U9{+  
try{ c_8mQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;HLMU36q  
int nCount = input.readInt(); <J_,9&\
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nStartPos = new long[nCount]; 77=y!SDP  
nEndPos = new long[nCount]; C6=;(=?C  
for(int i=0;i<nStartPos.length;i++) 'mp{O  
{ .5Z@5g`  
nStartPos = input.readLong(); 3vGaT4TDx  
nEndPos = input.readLong(); U*+!w@ .  
} |@bNd7=2d  
input.close(); Z@aL"@2]a  
} %>z8:oJ
 
catch(IOException e){e.printStackTrace ();} mLx
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catch(Exception e){e.printStackTrace ();} r@
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} 
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private void processErrorCode(int nErrorCode) 4`5Qt=}  
{ E,yzy[gl  
System.err.println("Error Code : " + nErrorCode); =x.v*W]F`  
} ([XyW{=h!  
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//停止文件下载 $v}8lBCr3  
public void siteStop() ThqfZl=V  
{ a!J ow?(  
bStop = true; L4A/7Ep  
for(int i=0;i<nStartPos.length;i++) Bw/H'Y  
fileSplitterFetch.splitterStop(); /dvnQW4}8  
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} GHsdLe=t0#  
} !vo'8r?&  
//负责部分文件的抓取 ][K8\  
**FileSplitterFetch.java &8YI)G%  
*/ ; dHOH\,:  
package NetFox; iKEKk\j-w  
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import java.io.*; I8oKa$RF  
import java.net.*; AiHDoV+-  
'*{Rn7B5  
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public class FileSplitterFetch extends Thread { \w\47/k{  
Va[dZeoy  
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String sURL; //File URL {^O/MMB\\%  
long nStartPos; //File Snippet Start Position cM'[;u  
long nEndPos; //File Snippet End Position }PD(kk6fX  
int nThreadID; //Thread's ID w0%ex#lkm  
boolean bDownOver = false; //Downing is over ]~x/8%e76  
boolean bStop = false; //Stop identical hE`%1j2(  
FileAccessI fileAccessI = null; //File Access interface D2*Q1n  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
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{ hD.wKX?oO  
this.sURL = sURL; ?j$8Uy$$  
this.nStartPos = nStart; ump:dL5{  
this.nEndPos = nEnd; ?;7>`F6ld  
nThreadID = id; M #RuI%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  ~9jP++&  
} &IPK5o,  
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public void run() GN"LU
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{ GQAg ex)D  
while(nStartPos < nEndPos && !bStop) ^|12~d_.T  
{ Y%cA2V\#m  
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try{ l8Iy03H  
URL url = new URL(sURL); 7(iRz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hQLx"R$  
httpConnection.setRequestProperty("User-Agent","NetFox"); E0%Y%PQ**{  
String sProperty = "bytes="+nStartPos+"-"; jl%eO.  
httpConnection.setRequestProperty("RANGE",sProperty); 1UWgOCc  
Utility.log(sProperty); X1QZEl  
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InputStream input = httpConnection.getInputStream(); K]Cs2IpI  
//logResponseHead(httpConnection); iK0J{
'  
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byte[] b = new byte[1024]; +uXnFf d^  
int nRead; "JGig!9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +GtGyp  
{ ^7<mlr  
nStartPos += fileAccessI.write(b,0,nRead); &y wY?ox  
//if(nThreadID == 1) exU=!3Ji  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p%tg->#L  
} 90k|u'ikOp  
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Utility.log("Thread " + nThreadID + " is over!"); f3B8,>  
bDownOver = true; 4T\/wyq0  
//nPos = fileAccessI.write (b,0,nRead); ^u&Khc~ y  
} W
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catch(Exception e){e.printStackTrace ();} jmVy4* P_  
} \(t>(4s_~  
} ;AA7wK 4  
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//打印回应的头信息 Gl:T   
public void logResponseHead(HttpURLConnection con) _jKVA6_E  
{ rZ4<*Zegv  
for(int i=1;;i++) KftM4SFbK  
{ Pu*UZcXY  
String header=con.getHeaderFieldKey(i); |W];v@b\y  
if(header!=null) eV}Tx;1|}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); RxG./GY  
Utility.log(header+" : "+con.getHeaderField(header)); @
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else }r<^]Q*&p  
break; [,X,2  
} !9OgA  
} ()JDjzQT  
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public void splitterStop() CUcjJ|M
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{ mQuaO# I,  
bStop = true; Qn&^.e9I  
} z3LPR:&Z  
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} 1<e%)? G  
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/* ixpG[8s  
**FileAccess.java mSeNM  
*//文件访问(定位，写) '~a$f;: Dv  
package NetFox; 2 ZXF_ o  
import java.io.*; h%e!f#  
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public class FileAccessI implements Serializable{ 9F!&y-  
~[6|VpGc:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !qv;F?2 <g  
RandomAccessFile oSavedFile; yt,;^o^  
long nPos; fdHxrH>*  
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public FileAccessI() throws IOException y Dw!u[:  
{ sR
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this("",0); X.|0E87  
} $4,6&dw
g  
 #0H[RU?  
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public FileAccessI(String sName,long nPos) throws IOException 4+bsG6i  
{ I%xJ)fIK  
oSavedFile = new RandomAccessFile(sName,"rw"); IBsn>*ja<  
this.nPos = nPos; Z_+No :F7I  
oSavedFile.seek(nPos); `^{P,N>X  
} CgE5
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public synchronized int write(byte[] b,int nStart,int nLen) 1^dWmxUZH  
{ L,L7WObA  
int n = -1; @kymL8"2w  
try{ v:;cTX=x`#  
oSavedFile.write(b,nStart,nLen); 5!*a,$S  
n = nLen; xc?<:h"  
} rfpxE>_|G  
catch(IOException e) E3.s8}}  
{ 2_v>8B  
e.printStackTrace ();
:"]ei@  
} =<xbE;,0  
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return n; _Oq\YQb v  
} miqCUbcU  
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} p7er04/}\  

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/* ~yN,FpD  
**SiteInfoBean.java yjzNU5F  
*/ Xi.?9J
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package NetFox; lX3h'h  
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~O-8h0d3  
public class SiteInfoBean { TVA1FD
 
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private String sSiteURL; //Site's URL EM}z-@A>  
private String sFilePath; //Saved File's Path #J_i 5KmXJ  
private String sFileName; //Saved File's Name FO$Tn+\6  
private int nSplitter; //Count of Splited Downloading File UepBXt3)  
+_Z/VQv  
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public SiteInfoBean() b??1Up  
{//nSplitter的缺省值为5 (P-<9y@  
//default value of nSplitter is 5 K2 2Xo<3  
this("","","",5); g_U6
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} X Rn=;gK%J  
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{J$aA6t:"T  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $!Tw`O
 
{ C+5nft6:  
sSiteURL= sURL; 8vK&d>  
sFilePath = sPath; E12k1gC`  
sFileName = sName; KJ_R@,v\  
this.nSplitter = nSpiltter; l.$#IE  
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se[};t:  
} m@YLZ  
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public String getSSiteURL() ,H*3_c&Q  
{ #ZA YP  
return sSiteURL; 30@ GFaab  
} ^dqEOW  
7_,gAE:kG  
.E&~]<  
public void setSSiteURL(String value) kns]P<g  
{ |+;"^<T)l  
sSiteURL = value; VzesqVx  
} 5oS\uX|  
o6 /?WR9  
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public String getSFilePath() q@:&^CS  
{ LxT]-  
return sFilePath; YVT^}7#
  
} DZue.or  
s><co]  
AM>:AtY  
public void setSFilePath(String value) :z\STXq  
{ \+xsJbEV  
sFilePath = value; 4"sP= C  
} c'b,=SM  
~"k'T9QBY  
D6w0Y:A{.  
public String getSFileName() 7nmo p7  
{ z( wXs&z;  
return sFileName; {/ta1&xyG  
} ''
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public void setSFileName(String value) Ty=}A MMyE  
{ kbY@Y,:w  
sFileName = value; [C$ 0HW  
} #_d%hr~d  
}1V&(#H2  
|($pXVLH`  
public int getNSplitter() tz,FK;8  
{ ?D_zAh?pW  
return nSplitter; DjIs"5Iei  
} x>^S..K}L%  
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public void setNSplitter(int nCount) ' vwBG=9C  
{ 6{M.S}.^  
nSplitter = nCount; iaB5t<t1r  
} GOt@x9%  
} /?sV\shy  
[#:k3aFz  
Ev%\YI!MaY  
/* QUt!fF@t  
**Utility.java 157X0&EX  
*/ pPE4~g 05h  
package NetFox; <~dN23)  
4P8:aZM  
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public class Utility {  :9<5GF(  
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public Utility() R:Lu)d>=  
{ 4Xz|HU?  
Xy._&&pt  
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} g0l- n  
bu]bfnYi9  
//线程睡眠 G
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public static void sleep(int nSecond) d^7<l_u~ !  
{ !Ej<J&e  
try{ Rh=h{O  
Thread.sleep(nSecond); {?8rvAjY  
} i|t$sBIh  
catch(Exception e) q45n.A6a  
{ z8oSh t`+  
e.printStackTrace (); ;.iy{&$  
} MStaP;|  
}
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,D8Tca\v  
//日志 BEw(SQH  
public static void log(String sMsg) ?IK[]=!  
{ ||hd(_W8  
System.err.println(sMsg); aePk^?KbB  
} *`kh}  
k@?<Aw8_X  
:0J;^@  
public static void log(int sMsg) 5lT lZRH1  
{ PH6uP]  
System.err.println(sMsg); ="V6z$N  
} LVSJK.B  
} mz47lv1?  
HxjhP(  
C`fQ` RL\  
/* }u :sh >2  
**TestMethod.java m9r X  
*/ (UCWSA7oc  
package NetFox; b<%6aRC\  
#}.db?[Rv  
dP82bk/e  
public class TestMethod { C[75!F   
Qk((H~I}  
d;`JDT  
public TestMethod() dI`b AP;\  
{ ///xx/weblogic60b2_win.exe y@F{pr+dA  
try{ hUqIjcuL4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :>|[ o&L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ).\%a h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `,J\E<4J  
fileFetch.start(); L9T|*?||  
} u BvN*L
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catch(Exception e){e.printStackTrace ();} Kg56.$  
2vynz,^ET  
4v;/"4)'  
} bYiaJ  
YQ]W<0(  
env]*gx+=  
public static void main(String[] args) jVr:O`  
{ =m UtBD.;  
new TestMethod(); /)j:Y:5  
} {a(TT)d  
} $. Ih-  
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