http断点续传简单实现（java)

/* =(b;Cow  
**SiteFileFetch.java ^l;nBD#nJ  
*/ Z<6xQTx  
package NetFox; e|u|
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import java.io.*; b}4k-hZL  
import java.net.*;  Hi#'h  
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public class SiteFileFetch extends Thread { NKB,D$!~&  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "|w..%Wc  
long[] nStartPos; //开始位置 0o2o]{rM{2  
long[] nEndPos; //结束位置 ;%P$q9*C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +hL+3`TD#H  
long nFileLength; //文件长度 "f\2/4EIl  
boolean bFirst = true; //是否第一次取文件 zq-"jpZG  
boolean bStop = false; //停止标志 {^gbS  
File tmpFile; //文件下载的临时信息 AEaT  
DataOutputStream output; //输出到文件的输出流 2)]C'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :" Q!Q@>  
public SiteFileFetch(SiteInfoBean bean) throws IOException j|gv0SI_ w  
{ TtEc~m  
siteInfoBean = bean; fI(u-z~,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +N1oOcPC>C  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?F'gh4  
if(tmpFile.exists ()) y]QG;  
{ hWpn~q  
bFirst = false; '(A)^K>+  
read_nPos(); T0n=nC}<  
} %\#s@8=2u  
else J&UFP{)  
{ |1J=wp)#  
nStartPos = new long[bean.getNSplitter()]; *%_:[>  
nEndPos = new long[bean.getNSplitter()]; > ^fY`x,  
} R< @o]p  
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} $~c?qU  
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public void run() +F q`I2l|  
{ f2Frb  
//获得文件长度 SvC|"-[mJ  
//分割文件 F_;oZ   
//实例FileSplitterFetch "8|y  
//启动FileSplitterFetch线程 oZ95)'L,  
//等待子线程返回 opTDW)  
try{ CK[2duf^~  
if(bFirst) B;tU+36nM  
{ Cd)e_&  
nFileLength = getFileSize(); Et~b^8$>  
if(nFileLength == -1) mN3}wJ}J  
{ h+F@apUS  
System.err.println("File Length is not known!"); M$g%kqa  
} G|FF  
else if(nFileLength == -2) jq(3y|6,  
{ CBdSgHA3>  
System.err.println("File is not access!"); 7 y}b (q=  
} k+S+: 5  
else -a(f-  
{ =1t#$JG  
for(int i=0;i<nStartPos.length;i++) m)9N9Ii#)  
{ <K!5N&vh  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} 'TpW-r:  
for(int i=0;i<nEndPos.length-1;i++) l!e8=QlJ  
{ l=*^FK]L`  
nEndPos = nStartPos[i+1]; |sz`w^#  
} Ib.`2@o&  
nEndPos[nEndPos.length-1] = nFileLength; 'JY*K:-  
} UI|L;5  
} D.xN_NK"  
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//启动子线程 @<Au|l`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ls#
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for(int i=0;i<nStartPos.length;i++) i.2O~30ST  
{ ~LGkc t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ElAJR4'{*i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), adtK$@Yeg  
nStartPos,nEndPos,i); B'6^E#9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hk4f)z  
fileSplitterFetch.start(); ?cdSZ'49[  
} _H@s^g  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dj4 g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
{;^booq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Us.yKAHPV  
nEndPos = " + nFileLength); `Yp\.K z  
// fileSplitterFetch[nPos.length-1].start(); ERQa,h/  
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//等待子线程结束 8,2l >S  
//int count = 0; m3XL;1y:a  
//是否结束while循环 B#o(21s  
boolean breakWhile = false; Dr6"~5~9w  
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while(!bStop) 3P Twpq1  
{ 0K7]<\)  
write_nPos(); pVn6>\xa  
Utility.sleep(500); U,)Ngnd  
breakWhile = true; _v4
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for(int i=0;i<nStartPos.length;i++) mH*42XC*  
{ b,5H|$nLu  
if(!fileSplitterFetch.bDownOver) #{7=  
{ q]:+0~cz  
breakWhile = false; n"Ec%n  
break;
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} Y{Kpopst  
} <'op  
if(breakWhile) ;&e5.K+.Z  
break; VuFMjY  
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!;lA+O-t  
//count++; >4GhI65  
//if(count>4) 7>xxur&  
// siteStop(); |DfYH~@(  
} ,^O**k9F  
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System.err.println("文件下载结束！"); N J:]jd  
} k#`.!yI,  
catch(Exception e){e.printStackTrace ();} O]w&uim  
} (rFY8oHD  
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//获得文件长度 qfE/,L(B  
public long getFileSize() %^^2  
{ ZA>hN3fE'  
int nFileLength = -1; ttLChL  
try{ -Qo`UL.}  
URL url = new URL(siteInfoBean.getSSiteURL()); dW;{,Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X;sl?8HG!<  
httpConnection.setRequestProperty("User-Agent","NetFox"); `Q1T-H_  
#!h
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int responseCode=httpConnection.getResponseCode(); T2Cdw\  
if(responseCode>=400) +OK.[ji?  
{ R|{AIa{}  
processErrorCode(responseCode); kxoJL6IC  
return -2; //-2 represent access is error O(,Ezyx  
} 9?gLi!rd  
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String sHeader; `j[)iok  
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for(int i=1;;i++) fS-#dJC";`  
{ !40{1U&@a`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LYGFEjS[  
//Utility.log(in.readLine()); V!c
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sHeader=httpConnection.getHeaderFieldKey(i); {"y{V  
if(sHeader!=null) j9%u&  
{ G9z Q{E  
if(sHeader.equals("Content-Length")) \%&QIe;:k  
{ B
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4u X<sJ*  
break; |^Try2@  
} C5i]n? )S  
} 9+@_ZI-  
else //Ioh (N  
break; =NAL*4c+  
} O-wR48Q  
} ?YXl.yj  
catch(IOException e){e.printStackTrace ();} Sl^HMO  
catch(Exception e){e.printStackTrace ();} tNbCO+rZ  
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Utility.log(nFileLength); V;=SncUb  
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return nFileLength; y_qFX
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} U?>P6p  
!-x^b.${B  
Vy
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//保存下载信息（文件指针位置） .zlUN0oe  
private void write_nPos() ; z:}OD  
{ h_?D%b~5
 
try{ h\C  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9g"a`a?c  
output.writeInt(nStartPos.length); \PU|<Ru.  
for(int i=0;i<nStartPos.length;i++) V5K`TC^
 
{ ?OYu BZF  
// output.writeLong(nPos); PAH; +  
output.writeLong(fileSplitterFetch.nStartPos); Niou=PI@  
output.writeLong(fileSplitterFetch.nEndPos); (8@._  
} SWO$#X /  
output.close(); eXnMS!g%Z  
} cli
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catch(IOException e){e.printStackTrace ();} n1DD+@  
catch(Exception e){e.printStackTrace ();} n0@e%=H)I  
} L\nWhmwl  
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//读取保存的下载信息（文件指针位置） ED[PP2[/  
private void read_nPos() pb$U~TvzhM  
{ -78 t0-lM  
try{ `P)a
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); B Gh%3"q  
int nCount = input.readInt(); _(<[!c!@0  
nStartPos = new long[nCount]; xlqRW"  
nEndPos = new long[nCount]; u` `FD  
for(int i=0;i<nStartPos.length;i++) mcb0%  
{ >\^:xxTf  
nStartPos = input.readLong(); P et0yH  
nEndPos = input.readLong(); _4owxYSDke  
} <2diO=  
input.close(); }c|Xr^  
} w80g)4V+  
catch(IOException e){e.printStackTrace ();} 0>Z/3i&?<  
catch(Exception e){e.printStackTrace ();} )]n:y M  
} h/V0}|b  
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private void processErrorCode(int nErrorCode) n_)d4d zl  
{  -"\z|OQ  
System.err.println("Error Code : " + nErrorCode); bf'@sh%W  
} 9FX'Uws  
4ZQXYwfC|  
/tJJ2 =%l  
//停止文件下载 Ca*^U-  
public void siteStop() #J, `a.  
{ JdfjOlEb  
bStop = true; 87>\wUJ  
for(int i=0;i<nStartPos.length;i++) K S,X$)9  
fileSplitterFetch.splitterStop(); /(E)|*~6  
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} Pd%o6~_*  
} hR[Qdu6r  
//负责部分文件的抓取 Q^DKKp  
**FileSplitterFetch.java %S]5wR6;_  
*/ f<!eJO:<'  
package NetFox; zRD{"uqi  
z4&|~-m,  
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import java.io.*; ;5q=/  
import java.net.*; 6S2D\Bt,_  
*'QD!Tc  
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public class FileSplitterFetch extends Thread { z./u;/:  
#Ji&.T^U/  
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String sURL; //File URL 71@V|$Dy  
long nStartPos; //File Snippet Start Position +smPR  
long nEndPos; //File Snippet End Position ^$6EO)<  
int nThreadID; //Thread's ID )C<c{mjk(  
boolean bDownOver = false; //Downing is over qI) Yzc/  
boolean bStop = false; //Stop identical T,!?+#  
FileAccessI fileAccessI = null; //File Access interface JyjS#BWi  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0V}%'Ec<e  
{ L/F!Y%=;[  
this.sURL = sURL; ql2>C.k3L  
this.nStartPos = nStart; 2
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this.nEndPos = nEnd; -$QzbRF5R  
nThreadID = id; ?r'rvu'/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 R}#?A%,*  
} 3(}W=oI  
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public void run() TF^Rh4  
{ # yAt `
 
while(nStartPos < nEndPos && !bStop) {}s7q|$  
{ >IJH#>i  
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try{ @tM1e<  
URL url = new URL(sURL); bvUjH5.7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GghZ".O  
httpConnection.setRequestProperty("User-Agent","NetFox"); W+cmn)8  
String sProperty = "bytes="+nStartPos+"-"; h&{9 &D1t  
httpConnection.setRequestProperty("RANGE",sProperty); ,*+F
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Utility.log(sProperty); [as\>@o  
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InputStream input = httpConnection.getInputStream(); q$yTG!q*  
//logResponseHead(httpConnection); dli?/U@hO  
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byte[] b = new byte[1024]; &j<B22t!  
int nRead; mcP]k8?C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -S"YEH9  
{ ,_!pUal  
nStartPos += fileAccessI.write(b,0,nRead); ;*BG{rkr  
//if(nThreadID == 1) T[`o$j6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q;*TnVbJ  
} S4n\<+dR<  
`%
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Utility.log("Thread " + nThreadID + " is over!"); Y^M3m'd?  
bDownOver = true; +4Aj/$%[q  
//nPos = fileAccessI.write (b,0,nRead); N<zD<q  
} *Ew`Fm H  
catch(Exception e){e.printStackTrace ();} (oBvpFP33  
} bg'Qq|<U  
} bE74Ui  
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//打印回应的头信息 %c<e`P;  
public void logResponseHead(HttpURLConnection con) h8&VaJ  
{ \uQ yp*P1s  
for(int i=1;;i++) xA& tVQ2!  
{ z\]]d?d?;  
String header=con.getHeaderFieldKey(i); 7y5`YJ}!  
if(header!=null) _D1Uc|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )\s{\u \  
Utility.log(header+" : "+con.getHeaderField(header)); C< 3`]l  
else g`i?]6c}jt  
break; s/"&k  
} n0bm 'qw  
} Hz) Xn\x  
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public void splitterStop() sG7G$G*ta!  
{ WWhAm{m  
bStop = true; fd!bs*\X  
} o%;R4 s,  
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} lD)ZMaaS3  
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/* -N $4\yp  
**FileAccess.java :[xFp}w{  
*//文件访问(定位，写) G8z.JX-7g  
package NetFox; "m,)3zND3  
import java.io.*; R&KFF'%  
&OQ37(<_  
'i+j;.  
public class FileAccessI implements Serializable{ \NU^Jc_k7  
:%7y6V
*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 T&+*dyNxMK  
RandomAccessFile oSavedFile; PvF3a`&r  
long nPos; !k@(}CN_*  
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public FileAccessI() throws IOException B6ee\23  
{ C$WUg<kcK'  
this("",0); r&+8\/{  
} +i^@QNOa  
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public FileAccessI(String sName,long nPos) throws IOException 3w!8PPl  
{ w_qX~d/  
oSavedFile = new RandomAccessFile(sName,"rw"); V1di#i:  
this.nPos = nPos; o-i9 :AHs  
oSavedFile.seek(nPos); .3>`yL  
} iOY: a  
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A\ARjSdb  
public synchronized int write(byte[] b,int nStart,int nLen) '^B[Krs'Z`  
{ Cq8.^=}_  
int n = -1; 8! eYax   
try{ L7\V^f%yCm  
oSavedFile.write(b,nStart,nLen); Rtpk
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n = nLen; 9U&~H*Hf  
} 4
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catch(IOException e) 8k
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{ |ht:_l 8  
e.printStackTrace (); 7md,!|m
 
} gZq_BY_U  
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return n; B703{k  
} *!oV?N[eA'  
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} 4j|IG/m  
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/* :3b.`s(M  
**SiteInfoBean.java A |u-VXQ  
*/ qXqGhHoe;  
package NetFox; 2ieyU5q7#  
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public class SiteInfoBean { B/O0 ~y!n  
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private String sSiteURL; //Site's URL |xa
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private String sFilePath; //Saved File's Path )_n=it$  
private String sFileName; //Saved File's Name &cGa~
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private int nSplitter; //Count of Splited Downloading File |PtfG2Ty?  
%lq[,6?>5  
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public SiteInfoBean() w)N~u%  
{//nSplitter的缺省值为5 9U>OeTh(  
//default value of nSplitter is 5 )Cu2xRr^`  
this("","","",5); ^'\JI  
} "UX/yLc3(  
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a  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +Jm~Um!  
{ NC%96gfD  
sSiteURL= sURL; 60TM!\  
sFilePath = sPath; <$(y6+lY  
sFileName = sName; 4mjlat(d  
this.nSplitter = nSpiltter; v}LI-~M>U  
: &bJMzB  
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} v]Fw~Y7l!  
"%}24t%  
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public String getSSiteURL() A!cY!aQ  
{ :6MV@{;PJ  
return sSiteURL; .0YcB  
} a8$4  
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public void setSSiteURL(String value) Al1_\vx7  
{ n:|a;/{I]9  
sSiteURL = value; {p.^E5&  
} &@K6;T  
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public String getSFilePath() 9(3]t}J5 d  
{ ZIN1y;dJ  
return sFilePath; nll=Vd[  
} i50E#+E8  
en>n\;U  
> ^=n|%  
public void setSFilePath(String value) ~R&rQJJeJ  
{ qj9[mBkP"  
sFilePath = value; U&i#cF  
} Z`_x|cU?J  
Lk)I;;  
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public String getSFileName() L;lu)|b"  
{ i?ZVVE=r  
return sFileName; !2Gua1z!CJ  
} D
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6f2?)jOW^N  
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public void setSFileName(String value) X%mga~fB  
{ %~I&T".iC  
sFileName = value; |8pSMgN  
} denxcDFu/~  
{#st>%i  
jzJQ/ZFS  
public int getNSplitter() Gphy8~eS  
{ n}b{u@$  
return nSplitter; XV/7K"  
} _aYhW{wW  
#W6 6`{>  
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public void setNSplitter(int nCount) idB1%?<  
{ oi m7=I0  
nSplitter = nCount; p5jR;nOZ%l  
} !E&l=*lM.  
}
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(/At+MF3E  
/* ^vxx]Hji  
**Utility.java ,,H;2xYf  
*/ F!3p )?  
package NetFox; :pM)I5MN[  
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@<3E`j'p  
public class Utility { DXG`%<ZMn  
ZJF"Yo  
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public Utility() Ell14Iki  
{ 'z^'+}iyv  
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} J6[}o4Z  
9% C]s  
//线程睡眠 T ay226  
public static void sleep(int nSecond) Auc&dpW  
{ 'Kk/ J+6U  
try{ >;XtJJS  
Thread.sleep(nSecond); gyq6LRb  
} CuK>1_Dq  
catch(Exception e) Fm=jgt3wv8  
{ ia3Q1 9r  
e.printStackTrace (); :1Nc6G  
} etT9}RbQ  
} \?oT.z5VG&  
k;jl3GV  
//日志 yKuZJXGVo  
public static void log(String sMsg) '$Z@oCY#  
{ [) 0JI6  
System.err.println(sMsg); |||m5(`S  
} VXiU5n^  
)sW!s3>S>  
$3B%4#s  
public static void log(int sMsg) \#JX
ch  
{ %f'=9pit  
System.err.println(sMsg); Xq )7Im}?  
} jI'?7@32`  
} vmEn$`&2t  
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?A;RTM  
/* O:8 u^TP  
**TestMethod.java h<)ceD<,  
*/ qE3Ud:j  
package NetFox; ~"0{<mMcX  
.?rs5[th*  
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public class TestMethod { *^Zt)U1$|  
Kp*3:
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f[D%(  
public TestMethod() X31%T"  
{ ///xx/weblogic60b2_win.exe 0C.5Qx  
try{ y9?*H?f,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Go1xyd:k  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); GApvRR+Z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pY-!NoES  
fileFetch.start(); ~Er0$+q=Y;  
} [T4{K&  
catch(Exception e){e.printStackTrace ();} 5L<A7^j  
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} r>! @Z2%s  
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public static void main(String[] args) *J]p/<> {  
{ \a7m!v  
new TestMethod(); IJKdVb~   
} c~/poFj  
} ;hODzfNkS  
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