http断点续传简单实现（java)

/* vnsSy
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**SiteFileFetch.java Tx+ p8J|Yr  
*/ ?R?Grw)`H  
package NetFox; r=csi  
import java.io.*; CM 9P"-  
import java.net.*; i>Iee^_(  
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public class SiteFileFetch extends Thread { .)ST[G]WK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean A^pW]r=Xtk  
long[] nStartPos; //开始位置 Z\!rH"8
 
long[] nEndPos; //结束位置 7Dl%UG]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Kfjryo9  
long nFileLength; //文件长度 ="lI i$>O  
boolean bFirst = true; //是否第一次取文件 8IWwjyRr  
boolean bStop = false; //停止标志 *CUdGI&  
File tmpFile; //文件下载的临时信息 vvh.@f  
DataOutputStream output; //输出到文件的输出流 aYj%w  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） h*'d;_(,  
public SiteFileFetch(SiteInfoBean bean) throws IOException }J;~P 9Y  
{
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siteInfoBean = bean; eUs-5 L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); VG\
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6F ;Or  
if(tmpFile.exists ()) LVmY=d>  
{ N*1  
bFirst = false; *tG11gR,&  
read_nPos(); 0#=W#Jl>  
} %^')G+>i  
else 8*)4"rS  
{ Doj(.wm~  
nStartPos = new long[bean.getNSplitter()]; $nFAu}%C  
nEndPos = new long[bean.getNSplitter()]; 6h@+?{F.  
} hNVMz`r  
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} E!dp~RwZu  
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public void run() fM9xy \.  
{ \>;%Ji  
//获得文件长度 &E]"c]i+  
//分割文件 <{ #<5 8  
//实例FileSplitterFetch tj#b_u z  
//启动FileSplitterFetch线程 [)iN)$Mv  
//等待子线程返回 qzlER  
try{ t[j9R#02?  
if(bFirst) 2$DSBQEx  
{ 5*XH6g F  
nFileLength = getFileSize(); _Ff
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if(nFileLength == -1) 7?"9J`*  
{ }+JLn%H)  
System.err.println("File Length is not known!"); AgCs;k&IG  
} >.@MR<H#5  
else if(nFileLength == -2) U2=hSzY  
{ %Y 2G  
System.err.println("File is not access!"); 0/*X=5  
} q06@SD$   
else 4%>+Wh[  
{ 43F^J
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for(int i=0;i<nStartPos.length;i++) :P"9;$FY  
{ :1NYpsd.i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DZ%8 |PmB  
} 5IO3 %p?  
for(int i=0;i<nEndPos.length-1;i++) mVHFT~x7}  
{ }Oh5Nm)  
nEndPos = nStartPos[i+1]; K_FBy  
} a^x  0 l  
nEndPos[nEndPos.length-1] = nFileLength; ja:\W\xhJ  
} 5 Af?Yxv  
} v'$ykZ!Z  
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//启动子线程 6<+8}`@B>G  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) Ul9b.`6  
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y& m<lnB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~"\P~cg0J  
nStartPos,nEndPos,i); .;j"+Ef   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y "<JE<X  
fileSplitterFetch.start(); }Uq/kei^P  
} ![j(o!6&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;wpW2%&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); R<t&F\>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8db6(Q~P  
nEndPos = " + nFileLength); *eMLbU7  
// fileSplitterFetch[nPos.length-1].start(); `}ZL'\G  
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//等待子线程结束 bf{Ep=-  
//int count = 0; VgUvD1v?}  
//是否结束while循环 hN!.@L  
boolean breakWhile = false; k:W=5{[  
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}
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while(!bStop) 1ME|G"$;  
{ ^75pV%<%  
write_nPos(); .!9Vt#  
Utility.sleep(500); "hz>{oe  
breakWhile = true; i^~sn `o  
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for(int i=0;i<nStartPos.length;i++) g+VRT,r  
{ t% <pbZO  
if(!fileSplitterFetch.bDownOver) 5BZ+b_A>VV  
{ EwC5[bRjUp  
breakWhile = false; }`?7\\6  
break; JHHb|  
} #V,LNX)  
} n&3iz05}  
if(breakWhile) e3G7K8  
break; .`b4h"g:  
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//count++; @^BS#  
//if(count>4) 2J1B$.3'  
// siteStop(); 5^bh.uF  
} 3KB|NS  
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System.err.println("文件下载结束！"); ZE{aS4c  
} dVij <! Lu  
catch(Exception e){e.printStackTrace ();} N;e}dwh&  
} /vMQF+  
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//获得文件长度 &IIJKn|_  
public long getFileSize() j0Id!o  
{ S5zpUF=  
int nFileLength = -1; CD*f4I#d  
try{ tj`tLYOZ@-  
URL url = new URL(siteInfoBean.getSSiteURL()); ]:[)KZ~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9<+;hH8J_r  
httpConnection.setRequestProperty("User-Agent","NetFox"); vQ?MM&6  
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int responseCode=httpConnection.getResponseCode(); 3Pw%[q=g  
if(responseCode>=400) 9;}L{yve  
{ ~5x4?2  
processErrorCode(responseCode); ~NTDG  
return -2; //-2 represent access is error g/fp45s  
} ly9x1`?$  
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String sHeader; (jD'
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for(int i=1;;i++) UUt~W  
{ ZJiuj!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <L[T'ZE+  
//Utility.log(in.readLine()); yBUZVqqDa  
sHeader=httpConnection.getHeaderFieldKey(i); r@N39O*Wq  
if(sHeader!=null) Q"x`+?!  
{ L{+&z7M  
if(sHeader.equals("Content-Length")) 0(Yh~{  
{ )*q7pO\cty  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &<\4q  
break; IBn'iE[>  
} R!:eYoQ  
} OqAh4qa,$  
else tuL\7 (R  
break;  hg<"Yg=  
} bW,BhUb,|  
} E#IiyZ  
catch(IOException e){e.printStackTrace ();} ?uNTUU,  
catch(Exception e){e.printStackTrace ();} 4i ~eTb  
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Utility.log(nFileLength); `8$:F4%P  
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return nFileLength; 60
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} "t3uW6&  
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//保存下载信息（文件指针位置） SXT@& @E  
private void write_nPos() UBUB/NY  
{ ^VM"!O;h{  
try{ o>/uW8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s= -
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output.writeInt(nStartPos.length); i} NkHEK  
for(int i=0;i<nStartPos.length;i++) \F
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{ |IyM"UH  
// output.writeLong(nPos); E.zYi7YUKK  
output.writeLong(fileSplitterFetch.nStartPos); XZUB*P}]D  
output.writeLong(fileSplitterFetch.nEndPos); /h}wM6pg  
} ,u8ZS|9  
output.close(); >S-N|uR6  
} t(uB66(_F  
catch(IOException e){e.printStackTrace ();} S20nk.x  
catch(Exception e){e.printStackTrace ();} "Gi+zkVm  
} YG}p$\R  
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//读取保存的下载信息（文件指针位置） 2ZTyo7P  
private void read_nPos() #Of<1  
{ #2ZrdD"5kQ  
try{ x`j$9XN5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Eb4< 26A  
int nCount = input.readInt();  Xv? S  
nStartPos = new long[nCount]; HzgQI  
nEndPos = new long[nCount]; ?vL^:f["  
for(int i=0;i<nStartPos.length;i++) \pBYWf  
{ @@&@}IQcR1  
nStartPos = input.readLong(); j:de}!wc  
nEndPos = input.readLong(); it/C y\f  
} ]XpU'/h>q;  
input.close(); 
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} pDq^W@Rq  
catch(IOException e){e.printStackTrace ();} b3y,4ke"  
catch(Exception e){e.printStackTrace ();}
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} y<'2BTf  
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private void processErrorCode(int nErrorCode) #C=L^cSx(  
{ 2S7H_
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System.err.println("Error Code : " + nErrorCode); m\}\RnZu  
} Ue>A  
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//停止文件下载 ] fwTi(4y  
public void siteStop() pO7{3%  
{ 4/mj"PBKL  
bStop = true; vt(}ga  
for(int i=0;i<nStartPos.length;i++) F_M~!]<na  
fileSplitterFetch.splitterStop(); Xx9~  
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} o<Rxt *B  
} c-3YSrY  
//负责部分文件的抓取 -V<=`e  
**FileSplitterFetch.java =vqE=:X6  
*/ &s6(3k  
package NetFox; 9cw4tqTm  
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import java.io.*; I;|5C=!  
import java.net.*; EiIFVP   
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public class FileSplitterFetch extends Thread { t6,M  
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String sURL; //File URL Jz:W-o  
long nStartPos; //File Snippet Start Position Y"]eH{  
long nEndPos; //File Snippet End Position vI:bl~  
int nThreadID; //Thread's ID ,{mf+ 3&$,  
boolean bDownOver = false; //Downing is over w3]0 !)t1  
boolean bStop = false; //Stop identical u_/OTy  
FileAccessI fileAccessI = null; //File Access interface &|&YRHv  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7$dc?K  
{ LTls]@N  
this.sURL = sURL; nF!_q;+Vp  
this.nStartPos = nStart; W<Vzd4hR  
this.nEndPos = nEnd; w]+BBGYQKb  
nThreadID = id; iYfLo">  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {$QF*j  
} hz~CW-47  
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public void run() &0<R:K?>N  
{ 7yCx !P;  
while(nStartPos < nEndPos && !bStop) kvO`]>#;$?  
{ %N_S/V0`  
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try{ nY5n%>8  
URL url = new URL(sURL); K&a]pL6D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {]_{BcK+  
httpConnection.setRequestProperty("User-Agent","NetFox"); cI4qgV  
String sProperty = "bytes="+nStartPos+"-"; Z=/L6Zb  
httpConnection.setRequestProperty("RANGE",sProperty); |~"A:gf  
Utility.log(sProperty); .1?i'8TF  
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InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection); |9i/)LRXe  
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byte[] b = new byte[1024]; p$!+2=)gY  
int nRead; s"Pk-Dv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i\R\bv[9  
{
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nStartPos += fileAccessI.write(b,0,nRead); q!h*3mNm  
//if(nThreadID == 1) )b2E/G@X&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hu*>B  
} %IH|zSr)EM  
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Utility.log("Thread " + nThreadID + " is over!"); D!E 9@*Lf  
bDownOver = true; ]B.,7  
//nPos = fileAccessI.write (b,0,nRead); G`JwAy r'  
} yLa5tv/  
catch(Exception e){e.printStackTrace ();} "E[*rnsLN  
} = ]HJa
 
} ZzaW@6LJF  
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//打印回应的头信息 E?5B>Jer#  
public void logResponseHead(HttpURLConnection con)
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{ U!UX"r  
for(int i=1;;i++) qxCL  
{ 2dJ)4  
String header=con.getHeaderFieldKey(i); `r0 qn'*  
if(header!=null) n7!Lwq2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); lJQl$Wx^  
Utility.log(header+" : "+con.getHeaderField(header)); 7)It1i-  
else &\D<n;3  
break; Sw9mrhzJfe  
} G;#t6bk  
} ghd[G}  
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public void splitterStop() i@?<]n  
{ D@1
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bStop = true; H.G^!0j;  
} ia.B@u1/  
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} 6!PX! UkF  
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/* {_N(S]Z  
**FileAccess.java 4)Wzj4qW  
*//文件访问(定位，写) 0+`*8G)  
package NetFox; !Fs)"?  
import java.io.*; zSufU2  
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public class FileAccessI implements Serializable{ {'bkU9+  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K]Cs2IpI  
RandomAccessFile oSavedFile; iK0J{
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long nPos; >bP7}T  
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public FileAccessI() throws IOException pY5HW2TsY|  
{ p" W0$t.  
this("",0); z`{zqP:  
} l]=$<  
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public FileAccessI(String sName,long nPos) throws IOException /'^>-!8_1  
{ T:5%sN;#O  
oSavedFile = new RandomAccessFile(sName,"rw"); siZ_JJW  
this.nPos = nPos; L. ?dI82c  
oSavedFile.seek(nPos); gx R|S  
} W 9MZ  
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public synchronized int write(byte[] b,int nStart,int nLen) l'8wPmy%N  
{ #mx
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int n = -1; B>21A9&  
try{ QRa6*AYm  
oSavedFile.write(b,nStart,nLen); AQU: 0  
n = nLen; l+qtA~V&2  
} <T[ui  
catch(IOException e) epyYo&x}  
{ ai9,4  
e.printStackTrace (); *%+buHe  
} f=Y9a$.:M  
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return n; HBGA lZ  
} Upen/1bA  
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} HaUo+,=  
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/* z3LPR:&Z  
**SiteInfoBean.java C^O^Jj5X%  
*/ (ZsR=:9(  
package NetFox; HKw4}FC*  
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public class SiteInfoBean { Lxrn#Z eM  
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private String sSiteURL; //Site's URL "b7C0NE  
private String sFilePath; //Saved File's Path IV*$U7~  
private String sFileName; //Saved File's Name b;ZAz  
private int nSplitter; //Count of Splited Downloading File rJj~cPwL"  
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public SiteInfoBean() ( "z;Q?(  
{//nSplitter的缺省值为5 8iA(:Tb  
//default value of nSplitter is 5 5nb6k,+E  
this("","","",5); F\72^,0  
} F'*4:WD7  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n/D]r  
{ 4tTJE<y  
sSiteURL= sURL; z|H>jit+  
sFilePath = sPath; h]9^bX__Z  
sFileName = sName; Dw,f~D$+ic  
this.nSplitter = nSpiltter; W{aNS@1  
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} BT0hx!Ti  
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public String getSSiteURL() eQj/)@B:V  
{ F tjm@:X  
return sSiteURL; j]SkBZgik  
} ?yK\L-ad  
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public void setSSiteURL(String value)
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{ uD3_'a  
sSiteURL = value; e vuP4-[y  
} =<xbE;,0  
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public String getSFilePath() _Oq\YQb v  
{ miqCUbcU  
return sFilePath; xM\ApN~W  
} p
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public void setSFilePath(String value) { VO4""m  
{ ?Q2pD!L{  
sFilePath = value; RGmpkQEp  
} @Iu-F4YT  
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public String getSFileName() =ndKG5  
{ ak[)+_k_  
return sFileName; @( l`_Wx  
} ?f&I"\y  
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public void setSFileName(String value) 5{Wl(jwb  
{ RkzBn  
sFileName = value; T:$_1I $  
} G
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public int getNSplitter() y rk#)@/m  
{ flqTx)xE  
return nSplitter; 5@ug1F&  
} wn&2-m*a  
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public void setNSplitter(int nCount) 6*7&X#gG  
{ ':3KZ4/C  
nSplitter = nCount; FQ%mNowuj  
} 5FxU=M1gF  
} >.|gmo>b  
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/* 5,C,q%2  
**Utility.java Df (6DuW  
*/ o*_D  
package NetFox; 5mU_S\)4:z  
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public class Utility { `Z-`-IL  
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public Utility() jxvVp*-=<j  
{ nP^$p C  
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} / <p HDY  
0N.*c  
//线程睡眠 jTnu! H2o  
public static void sleep(int nSecond) /7^~*  
{ -bwl~3ZTi  
try{ OjZ@_V:  
Thread.sleep(nSecond); PW}.`  
} Cp%|Q.?  
catch(Exception e) EeO{G*pq  
{ W=
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e.printStackTrace (); rAKdf??  
} I1gu<a  
} }wVrmDh \  
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//日志 9=|5-?^  
public static void log(String sMsg) !r<7]nwV  
{ lK-I[i!  
System.err.println(sMsg); PO&`rr  
} :"4~VDu  
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public static void log(int sMsg) duI8^&|  
{ \cG'3\GI  
System.err.println(sMsg); \1ZfSc  
} qb Q> z+c  
} )n.peZ  
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/* =u(fP" |{  
**TestMethod.java yFSL7`p+  
*/ ^|Y!NHYH$Z  
package NetFox; 5 F-Q&  
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public class TestMethod { bm;4NA?Gg  
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public TestMethod() +~-|( y  
{ ///xx/weblogic60b2_win.exe DcOLK\  
try{ hXCDlCO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .NKN2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [Mi~4b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); mS0W@#|K  
fileFetch.start(); Wh,kJis<  
} gnQd#`  
catch(Exception e){e.printStackTrace ();} STI8[e7{  

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} _#+i;$cO-X  
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public static void main(String[] args) 7P  
{ <t8})
 
new TestMethod(); 2h=RNU|  
} wNlp4Z'[  
} V|7 cdX#H  
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