http断点续传简单实现（java)

/* nj53G67y  
**SiteFileFetch.java &JI8]JmU)  
*/ (J!+(H8  
package NetFox; 6i~WcAs  
import java.io.*; z]9MM 2+  
import java.net.*; |H+Wed|  
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public class SiteFileFetch extends Thread { :Zz '1C  
{> 0wiH#!E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \;"=QmRD%:  
long[] nStartPos; //开始位置 b
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long[] nEndPos; //结束位置 ox (%5c)b|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &IB|rw'9  
long nFileLength; //文件长度 {,~3.5u   
boolean bFirst = true; //是否第一次取文件 /gkX38  
boolean bStop = false; //停止标志 igR";OQk  
File tmpFile; //文件下载的临时信息 w)Qp?k d  
DataOutputStream output; //输出到文件的输出流 )%@J=&G8TT  
/
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >&5DsV.B  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]wG{!0pl  
{ NPe%F+X  
siteInfoBean = bean; 4Wm@W E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Tyf`j,=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7VFLJrt  
if(tmpFile.exists ()) C-[eaHJ'$  
{ 'ub@]ru|  
bFirst = false; $'hEz/  
read_nPos(); :A'y+MnK<  
} =zKM=qba  
else =$Nq  
{ e;}7G  
nStartPos = new long[bean.getNSplitter()]; Ak"m 85B  
nEndPos = new long[bean.getNSplitter()]; KNIn:K^/  
} 5,6"&vU,  
[ ~&/s:Vvo  
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} X*@dj_,  
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public void run() _8_R 1s  
{ 4u5-7[TZ  
//获得文件长度 ]F'
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//分割文件 g~A`N=r;h  
//实例FileSplitterFetch v<(  
//启动FileSplitterFetch线程 "mvt>X  
//等待子线程返回 h|{]B,.Lh  
try{ DG:Z=LuJr  
if(bFirst) [}0haTYc4  
{ Q|?L*Pq2I  
nFileLength = getFileSize(); 76h ,]xi  
if(nFileLength == -1) oEKvl3Hz_  
{ 4 VW[E1
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System.err.println("File Length is not known!"); #KexvP&*  
} o
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else if(nFileLength == -2) aH/ k
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{ k5.Ln
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System.err.println("File is not access!"); 'op|B@y  
} ;P%1j|7  
else [;),\\u,d  
{ O5nD+qTQ#  
for(int i=0;i<nStartPos.length;i++) EVC]sUT  
{ %.-4!vj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); GM f `A,>  
} T&u5ki4NE  
for(int i=0;i<nEndPos.length-1;i++) Doyx[zZ  
{ qm8B8&-  
nEndPos = nStartPos[i+1]; Cl8Cg~2  
} CSq4x5!_7>  
nEndPos[nEndPos.length-1] = nFileLength; B; h"lv  
} qwgPk9l  
} G[I"8iS,  
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//启动子线程 EC!02S  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Mc_YPR:
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for(int i=0;i<nStartPos.length;i++) .Una+Z  
{ 3E
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q%tXQP.r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W^LY'ypT  
nStartPos,nEndPos,i); ex (.=X 1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ""F5z,'  
fileSplitterFetch.start(); f=gW]x7'R+  
} V/ uP%'cd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '3DXPR^B6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iYm-tsER;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ']z{{UNUN  
nEndPos = " + nFileLength); YdC6k?tzS  
// fileSplitterFetch[nPos.length-1].start(); rkCx{pe9  
4`]^@"{  
]i ,{  
//等待子线程结束 D_^ nI:  
//int count = 0; KD7dye  
//是否结束while循环 Tg)|or/%  
boolean breakWhile = false; O6a<`]F  
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while(!bStop) j8{i#;s!"  
{ qqr?!vem6  
write_nPos(); f:|1_j  
Utility.sleep(500); 6J6BF%  
breakWhile = true; .A{tQ1&_  
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for(int i=0;i<nStartPos.length;i++) JZ*/,|1}EC  
{ ju8q?Nyhs  
if(!fileSplitterFetch.bDownOver) bj0G5dc=  
{ A_ N;   
breakWhile = false; 0c'<3@39k|  
break; KNpl:g3{<Q  
} yyRiP|hJ  
} '(yAfL 9}  
if(breakWhile) g:D>.lKd  
break; -)]Yr #Q  
e
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//count++; [{<`o5qR  
//if(count>4) 0gy/:T  
// siteStop(); =9["+;\e&  
} LW'D?p#  

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System.err.println("文件下载结束！"); wb5baY9  
} `maKN\;  
catch(Exception e){e.printStackTrace ();} ,+vy,<e&  
} R_ ,UMt  
2U\u4NO{  
[OV"}<V  
//获得文件长度 ," Wr"  
public long getFileSize() Z/;(fL  
{ >WQMqQ^t@  
int nFileLength = -1; Mxsa-?R;v  
try{ k,E{C{^M  
URL url = new URL(siteInfoBean.getSSiteURL()); EZy)A$|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \fyRsa)  
httpConnection.setRequestProperty("User-Agent","NetFox"); bv9i*]  
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int responseCode=httpConnection.getResponseCode(); LX
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if(responseCode>=400) '4Ixqb+  
{ B^Nf #XN(  
processErrorCode(responseCode); ;R5`"`  
return -2; //-2 represent access is error %C'?@,7C  
} &Gn 2tr  
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]kG"ubHV?h  
String sHeader; zyc"]IzOU  
c~$)UND^  
,o{9$H5{  
for(int i=1;;i++) Y. 5_6'Eo?  
{ 3yY}04[9<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /-ch`u md  
//Utility.log(in.readLine()); |`Ntv}  
sHeader=httpConnection.getHeaderFieldKey(i); c74.< @w  
if(sHeader!=null) F/bT)QT<f  
{ ^f &XQQY  
if(sHeader.equals("Content-Length")) L9\1+rq  
{ dh*ZKI^@(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2d(e:rh]  
break; *vN-Vb^2i)  
} *{@Nq=fE  
} )uIe&B  
else V>%rv'G8  
break; }bpQq6ZF  
} wj<6kG  
} 0hNA1Fh{U  
catch(IOException e){e.printStackTrace ();} mpEK (p  
catch(Exception e){e.printStackTrace ();}  $s c  
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Utility.log(nFileLength); OU(8V^.  
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return nFileLength; hh)`645=x  
} N1S{suic  
%2/EaaR  
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//保存下载信息（文件指针位置） p* (JjH  
private void write_nPos() 2K6qY)/_  
{ qQ/^@3tXL  
try{ n;Q7X>-f8`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /cdC'g  
output.writeInt(nStartPos.length); omu|yCK  
for(int i=0;i<nStartPos.length;i++) V-2(?auZd  
{ F>6|3bOR  
// output.writeLong(nPos); ~'H]jN  
output.writeLong(fileSplitterFetch.nStartPos); [{,T.;'<j  
output.writeLong(fileSplitterFetch.nEndPos); 4Zddw0|2  
} GL0L!="!  
output.close(); "]x'PI 4J  
} S9D<8j^  
catch(IOException e){e.printStackTrace ();} ~i{(<.he  
catch(Exception e){e.printStackTrace ();} -1_)LO&H  
} $q{!5-e  
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//读取保存的下载信息（文件指针位置） ")5":V~fN  
private void read_nPos() syj0.JD  
{ l -mfFN  
try{ w"|L:8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !cLo>,4  
int nCount = input.readInt(); a=1@*ID  
nStartPos = new long[nCount]; 8.=BaNU  
nEndPos = new long[nCount]; nFe<w  
for(int i=0;i<nStartPos.length;i++) q=m'^ ,gPS  
{ oj<gD  
nStartPos = input.readLong(); $am$EU?s  
nEndPos = input.readLong(); Xp% v.M  
} "5!oi]@>(  
input.close(); uc\Kg1{  
} \<>ih)J@tt  
catch(IOException e){e.printStackTrace ();} 7wqK>Y1a  
catch(Exception e){e.printStackTrace ();} CL;}IBd a  
} OU.6bmWy|  
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_
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private void processErrorCode(int nErrorCode) }W8;=$jr  
{ IGQFtO/x  
System.err.println("Error Code : " + nErrorCode); v^NIx q}U  
} >J?fl8  
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6]N;r5n  
//停止文件下载 /NFj(+&g+  
public void siteStop() >dD@j:Qc  
{ LEf^cM=>  
bStop = true; D%SlAzZ3  
for(int i=0;i<nStartPos.length;i++) X-Kh(Z  
fileSplitterFetch.splitterStop(); vX"*4m>b?+  
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"| g>'wM*  
} xn(kKB.  
} ?4&e;83_#y  
//负责部分文件的抓取 vWv"  
**FileSplitterFetch.java iByf{I>+  
*/ pRpBhm;iJ  
package NetFox; djG*YM\B  
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import java.io.*; 9T9!kb  
import java.net.*; MrFQ5:=  
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public class FileSplitterFetch extends Thread { i)#dWFDTv  
i$#;Kpb`^  
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String sURL; //File URL gPO}d  
long nStartPos; //File Snippet Start Position AKfDXy  
long nEndPos; //File Snippet End Position ((;!<5-`s  
int nThreadID; //Thread's ID Eyqa?$R  
boolean bDownOver = false; //Downing is over C2I_%nU Z1  
boolean bStop = false; //Stop identical p%Vt#?q  
FileAccessI fileAccessI = null; //File Access interface p)-^;=<B3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]Q1yNtN  
{ _6hQ %hv8  
this.sURL = sURL; ,R\ \%  
this.nStartPos = nStart; 3(N$nsi  
this.nEndPos = nEnd; NwvC[4  
nThreadID = id; &PHTpkaam  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _D&598xx  
} |SSSH  
/C:gKy4  
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public void run() 9Q.Yl&A  
{ vn8aFA  
while(nStartPos < nEndPos && !bStop) GL}]y -f  
{ ec;o\erPG  
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try{  |>^JRx  
URL url = new URL(sURL); SKN`2hD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /36:ms A  
httpConnection.setRequestProperty("User-Agent","NetFox"); G~a ZJ,  
String sProperty = "bytes="+nStartPos+"-"; {}przrU^c  
httpConnection.setRequestProperty("RANGE",sProperty); &Z@o Q
 
Utility.log(sProperty); RbnVL$c  
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InputStream input = httpConnection.getInputStream(); &r/Mi%  
//logResponseHead(httpConnection); nR~@#P\  
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byte[] b = new byte[1024]; O0v}43J[  
int nRead; F/{!tx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) T'9'G M  
{ Sz`,X0a  
nStartPos += fileAccessI.write(b,0,nRead); t3_O H^  
//if(nThreadID == 1) 0#hlsfc]\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1CZgb  
} T7%S #0,p  
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Utility.log("Thread " + nThreadID + " is over!"); 9TC,!0U{_.  
bDownOver = true; q3!bky\  
//nPos = fileAccessI.write (b,0,nRead); @S;'@VC  
} /,yd+wcW#  
catch(Exception e){e.printStackTrace ();} FVKTbvYn  
} J/$&NWF  
} 2%m BK  
&p@O_0nF  
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//打印回应的头信息 C,r;VyW6BI  
public void logResponseHead(HttpURLConnection con) v\ )W?i*l  
{ M%m4i9~!?  
for(int i=1;;i++) (L&d!$,Dv  
{ bI1N@
=  
String header=con.getHeaderFieldKey(i); {!L~@r  
if(header!=null) 9Y9GwL]T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :5<UkN)R(  
Utility.log(header+" : "+con.getHeaderField(header)); #;yZ  
else =; Ff4aF  
break;
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} x 9fip-  
} P= NDS2  
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public void splitterStop() 24eLB?H  
{ q0vQa  
bStop = true; 4D4j7  
} Y:[u1~a  
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} &h/Xku&0  
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U
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/* DvvK^+-~  
**FileAccess.java g2_"zDiw2  
*//文件访问(定位，写) onzxx4bax  
package NetFox; ON(kt3.h  
import java.io.*; k9!{IScq  
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" H\k`.j  
public class FileAccessI implements Serializable{ UCjld  
g($2Dk_F2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Iefn$  
RandomAccessFile oSavedFile; e\L8oOk#r  
long nPos; YOO+R{4(  
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public FileAccessI() throws IOException F)eelPZ+,  
{ 4V`G,W4^J  
this("",0); G"t5nHY\.  
} a:w#s}bL  
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public FileAccessI(String sName,long nPos) throws IOException G 3ptx! D  
{ NgPk&niM  
oSavedFile = new RandomAccessFile(sName,"rw"); bk[!8-b/a  
this.nPos = nPos; R6->t #n,  
oSavedFile.seek(nPos); +
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} \9T7A&  
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public synchronized int write(byte[] b,int nStart,int nLen) ckCE1e>s  
{ D0f]$  
int n = -1; J|73.&B  
try{ `ERz\`d~Y;  
oSavedFile.write(b,nStart,nLen); M_DwUS1?  
n = nLen; +NUG  
} X&H"51  
catch(IOException e) 5{,<j\#L  
{ W"{N Bi  
e.printStackTrace (); 8quaXVj^a  
} !4+<<(B=E  
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return n; OjA,]Gv6  
} CqC`8fD1  
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} p]c%f2E>d  
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fk-RV>yr  
/* 4*;MJ[|  
**SiteInfoBean.java K|=A:  
*/ q) KKvO  
package NetFox; !&E-}}<  
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public class SiteInfoBean { 8z\xrY  
j
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private String sSiteURL; //Site's URL GQ ;;bcj&  
private String sFilePath; //Saved File's Path B9S@(/"7  
private String sFileName; //Saved File's Name qH_Dc=~la  
private int nSplitter; //Count of Splited Downloading File "m>81-0  
Vxt+]5X  
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public SiteInfoBean() lp8v0e
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{//nSplitter的缺省值为5 u ^RxD^=L  
//default value of nSplitter is 5 <1!O1ab  
this("","","",5); #g!.T g'  
} 2 yz _  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *VN6cSq  
{ a8Wwq?@  
sSiteURL= sURL; xgtR6E^k  
sFilePath = sPath; }Y4qS  
sFileName = sName; -UT}/:a  
this.nSplitter = nSpiltter; HxI" 8A  
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&%Tj/Qx  
} `M6)f?|$.  
cB&:z)i4  
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public String getSSiteURL() RD&PDXT4  
{ Z3!`J&  
return sSiteURL; apxph2yvS  
} u]@['7  
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public void setSSiteURL(String value) Xn ;AZu^'R  
{ >(RkZ}z  
sSiteURL = value; jc9y<{~x/  
} 6W UrQFK  
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bZV
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public String getSFilePath() %8x#rohP  
{ *{{89E>wC  
return sFilePath; U/BR*Zn]*  
} :M5l*sIO2  
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Y <qm{e  
public void setSFilePath(String value) 9_s`{(0?  
{ ?bu>r=oIO]  
sFilePath = value; F6dP,(  
} L/^I*p,  
HpnWoDM  
8~gLqh8^V  
public String getSFileName() "zy7C*)>r  
{ I<tm"?q0  
return sFileName; 40 0#v|b  
} )dSi/  
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|^H5^k "Bv  
public void setSFileName(String value) ;*&-C9b  
{ Wv/=
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sFileName = value; GuL<Z1<c  
} >F&47Yn  
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)\^-2[;  
public int getNSplitter() `@s^(hc7i  
{ X\F|Tk3_  
return nSplitter; 5/z/>D;  
} X[TR3[1}  
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public void setNSplitter(int nCount) 29q _BR *:  
{ ^G-@06/!  
nSplitter = nCount; dC4'{n|7  
} 4xJQ!>6  
} >yh2Lri  
&iVs0R  
>@AB<$A  
/* RCLeA=/N@0  
**Utility.java C{wEzM:  
*/ M& CqSd  
package NetFox; g$o&Udgs  
;6hOx(>`=  
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public class Utility { '[O;zJN;  
*_g$MI  
&G$Ucc `  
public Utility() NW)1#]gg%  
{ H7+,*  
& "B=/-(  
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} D7qOZlX16  
.Xhr
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//线程睡眠 G9vpt M  
public static void sleep(int nSecond) G9@0@2aY8  
{ *k>n<p3dd  
try{ Q)z8PQl O  
Thread.sleep(nSecond); BDZ?Ez\Sg  
} xi;`ecqS<  
catch(Exception e) RY*U"G0#w  
{ 5i{j' {_(8  
e.printStackTrace (); EDs\,f}  
} ,3 u}x,  
} ,wdD8ZT'Ip  
hwNf~3eJk  
//日志 h3@v+Z<}  
public static void log(String sMsg) HiJE}V;Vq  
{ P}`H ~N~  
System.err.println(sMsg); B^jc3 VsR  
} J!7MZLb  
|IUWF%~^$+  
U|j`e5)  
public static void log(int sMsg) O!bOp=  
{ 5.J.RE"M  
System.err.println(sMsg); 
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} K,:N  
} 63x?MY6  
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yJe>JK~)  
/* Lbb0_-']  
**TestMethod.java {P#|zp4C{  
*/ &Z|P2dI  
package NetFox; VTHH&$ZNq  
wJY'  
n>U5R_T  
public class TestMethod { 6/dI6C!  
4]}'Hln*U  
H~z`]5CN  
public TestMethod() 42ivT_H  
{ ///xx/weblogic60b2_win.exe iM3V=&)  
try{ i8HTzv"J  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {U !g.rh  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8BNi1Qn$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); I ?.^ho  
fileFetch.start(); LvYB7<zk>  
} m/EFHS49  
catch(Exception e){e.printStackTrace ();} 4#hSJ(~7S  
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} r^ ZEImjc  
D=
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public static void main(String[] args) uOdl*|T?  
{ c<$OA=n  
new TestMethod(); EI^C{$Y  
} G[q$QB+  
} `%WU8Yv  
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