http断点续传简单实现（java)

/* (bi}?V*
 
**SiteFileFetch.java  *ta ``q  
*/ NIeT.!  
package NetFox; 5 fjeBfy  
import java.io.*; ja}_u}:  
import java.net.*; 4;_{*U-  
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public class SiteFileFetch extends Thread { ;BqYhi  
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SiteInfoBean siteInfoBean = null; //文件信息Bean jQzq(oDQw  
long[] nStartPos; //开始位置 ua*k{0[  
long[] nEndPos; //结束位置 AoL4#.r3H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 o&1ewE(O]  
long nFileLength; //文件长度 '$W@I  
boolean bFirst = true; //是否第一次取文件 s)#FqB8  
boolean bStop = false; //停止标志 Qwb=N  
File tmpFile; //文件下载的临时信息 *D1^Se  
DataOutputStream output; //输出到文件的输出流 0.C y4sH'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） u~\u8X3  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^#2w::Ds}!  
{ ppj
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siteInfoBean = bean; wp`a:QZ8N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bR6.Xdt.n  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");

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if(tmpFile.exists ()) quHq?oXV,  
{ );V6YE  
bFirst = false; hex:e2x  
read_nPos(); W[[3'JTF  
} D)XF@z;  
else V*rAZ0  
{ 1u7Kc'.xc  
nStartPos = new long[bean.getNSplitter()]; "qUUH4mR
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nEndPos = new long[bean.getNSplitter()]; y^tuybpZY<  
} Qx|m{1~-  
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} Io*`hA]  
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public void run() \Q<c Y<  
{ I.TdYSB  
//获得文件长度 Y;d$x}dh  
//分割文件 e.jrX;;$!&  
//实例FileSplitterFetch l=U@j T  
//启动FileSplitterFetch线程 Enn7p9&  
//等待子线程返回 IlJ6&9  
try{ wq!Gj]B  
if(bFirst) ?9nuL}m!a  
{ %Kx:'m%U  
nFileLength = getFileSize(); {^2``NYM_  
if(nFileLength == -1) vO!p8r F  
{ PXG)?`^NX  
System.err.println("File Length is not known!"); S\K;h/;V  
} NL 3ri7n  
else if(nFileLength == -2) .5'
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{ yB\}e'J^  
System.err.println("File is not access!"); MW8GM}Ho[  
} 6=s!~  
else #
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{ >&3M #s(w  
for(int i=0;i<nStartPos.length;i++) JsI`#  
{ m07= _4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); yKF"\^`@  
} X&fM36o7  
for(int i=0;i<nEndPos.length-1;i++) Z`<S_PPz  
{ wl H6  
nEndPos = nStartPos[i+1]; z[X>>P3<n  
} $L_-U~^  
nEndPos[nEndPos.length-1] = nFileLength; p'fq&a+  
} M_*"g>Z  
} <7R\
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//启动子线程 YKKZRlQo  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; hRTw8-wy:  
for(int i=0;i<nStartPos.length;i++) w%R(*,r6  
{ B-PN +P2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -/rP0h5#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {J;[
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nStartPos,nEndPos,i); x9q?^\x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V/"UDof  
fileSplitterFetch.start(); ^.)oQo SE  
} bHR
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,%7>%*nhk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2%UzCK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "C%<R  
nEndPos = " + nFileLength); G(W/.*  
// fileSplitterFetch[nPos.length-1].start(); b{J
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 |`[0U  
2\80S[f  
//等待子线程结束 P}hHx<L  
//int count = 0; ")m0{  
//是否结束while循环 p&dpDJ?d:=  
boolean breakWhile = false; VWf&F`^B(  
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while(!bStop) 5e=9~].7  
{ S?ELFq(g  
write_nPos(); 3y?I^ .B  
Utility.sleep(500); 4{4VC"fa  
breakWhile = true; cB#5LXbCE  
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for(int i=0;i<nStartPos.length;i++) Kab"r_'  
{ Qc1NLU9:  
if(!fileSplitterFetch.bDownOver) KSkT6_<  
{ 0N.B=j|  
breakWhile = false; pFb}5Q  
break; |8^53*f ?
 
} 2GeJ\1k  
} art L  
if(breakWhile) hZ@frbuowk  
break; r,I';vm<`  
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//count++; ! Rrk
 
//if(count>4) q,S[[{("  
// siteStop(); C:z+8wt  
} pY@$N&+W  
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System.err.println("文件下载结束！"); 9~3;upWu!  
} ) 0NKL:u  
catch(Exception e){e.printStackTrace ();} _yx~t  
} xib?XzxGo  
_[%2QwAUj*  
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//获得文件长度 7Yv1et |  
public long getFileSize() `Xs3^FJt  
{ a ]~Rp  
int nFileLength = -1; >-S?rXO  
try{ /wAx#[c[  
URL url = new URL(siteInfoBean.getSSiteURL()); v9*ugu[K9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o,qq*}=  
httpConnection.setRequestProperty("User-Agent","NetFox"); P}"=67$  
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int responseCode=httpConnection.getResponseCode(); XotiKCk|Aq  
if(responseCode>=400) rF@njw@  
{ /;5U-<qf  
processErrorCode(responseCode); y5@#leM  
return -2; //-2 represent access is error hHA!.u4&  
} 5;v_?M!UCK  
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String sHeader; qb$&BZj]|  
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for(int i=1;;i++) 4 H<.  
{ nu(;yIRP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^uiQZ%;  
//Utility.log(in.readLine()); {{:QtkN  
sHeader=httpConnection.getHeaderFieldKey(i); 1j_gQ,'20  
if(sHeader!=null) 6 4
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{ 
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if(sHeader.equals("Content-Length")) s7d4)A%  
{ 02$d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \k4em{K  
break; A4~-{.w=  
} &xWej2a!  
} N%f% U  
else
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break; Iwx~kvz\_(  
} ""f'L,`{.  
} IRknD3LX  
catch(IOException e){e.printStackTrace ();} p3,m),  
catch(Exception e){e.printStackTrace ();} 7!;H$mxP  
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Utility.log(nFileLength); +$YHdgZ.  
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return nFileLength; 9,?7mgZp  
} 1j*E/L  
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//保存下载信息（文件指针位置） ^qY?x7mx1  
private void write_nPos() eH_< <Xh!v  
{ XfQK kol  
try{ L`"j>),  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^O3i)GO  
output.writeInt(nStartPos.length); rT|wZz9$@  
for(int i=0;i<nStartPos.length;i++) im3BQIPR  
{ j4:Xel/  
// output.writeLong(nPos); ^]NFr*'!  
output.writeLong(fileSplitterFetch.nStartPos); i
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output.writeLong(fileSplitterFetch.nEndPos); %M*2j%6  
} 2EH0d6nt  
output.close(); ES)@iM?5  
} L.s$|%  
catch(IOException e){e.printStackTrace ();} MW2{w<-]7  
catch(Exception e){e.printStackTrace ();} ]]NTvr  
} -
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//读取保存的下载信息（文件指针位置） +O)Y7k{?C5  
private void read_nPos() I8/tD|3  
{ F!<!)_8Q  
try{ *zwo="WA\t  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); TT oW>RP#  
int nCount = input.readInt(); v~A*?WU;n  
nStartPos = new long[nCount]; h0?w V5H  
nEndPos = new long[nCount]; h])oo:u'/Q  
for(int i=0;i<nStartPos.length;i++) FR']Rj  
{ l<;~sag  
nStartPos = input.readLong(); q+
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nEndPos = input.readLong(); @1A.$:  
} @R Jr ~y0  
input.close(); W9QVfe#s  
} w6h*dh$w  
catch(IOException e){e.printStackTrace ();} IgN^~ag`  
catch(Exception e){e.printStackTrace ();} =6 3tp 9  
} J|w%n5Y  
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private void processErrorCode(int nErrorCode) [$c"}=g
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{ &`,Y/Cbw  
System.err.println("Error Code : " + nErrorCode); @*E=O|  
} Sf*gAwnW  
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,n2"N5{jw  
//停止文件下载 \ B'AXv6  
public void siteStop() 8F&Y;  
{ lL&U ioo}D  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) S!n?b|_  
fileSplitterFetch.splitterStop(); 1aZGt2;  
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} FKPR;H8>  
} *I[tIO\  
//负责部分文件的抓取 :H:
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**FileSplitterFetch.java aU@1j;se@  
*/ E $P?%<o  
package NetFox; ]V)*WP#a  
#q>\6} )  
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import java.io.*; ]57yorc`  
import java.net.*; 0gGr/78   
vOLa.%X]h  
/=T:W*C  
public class FileSplitterFetch extends Thread { %@:6&  
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String sURL; //File URL $wn0oIuW  
long nStartPos; //File Snippet Start Position CYlS8j  
long nEndPos; //File Snippet End Position LJom+PxF$x  
int nThreadID; //Thread's ID *<[zG7+&[  
boolean bDownOver = false; //Downing is over t 4VeXp6  
boolean bStop = false; //Stop identical 1=,y+Xpw  
FileAccessI fileAccessI = null; //File Access interface 7#c4.9b?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #WJ*)$A@&  
{
1{wbC)  
this.sURL = sURL; ef)zf+o  
this.nStartPos = nStart; LlS~J K  
this.nEndPos = nEnd; eco&!R[G  
nThreadID = id; S;y4Z:!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !{{gL=_@  
} +xgP&nw[-  
#a2gRg
  
(
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public void run() ->X>h_k.Y  
{ \*Yr&Lm  
while(nStartPos < nEndPos && !bStop) N!MDD?0  
{ 1/~=61msc  
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try{ ~@)s)K  
URL url = new URL(sURL); /[D_9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @OGG]0 J  
httpConnection.setRequestProperty("User-Agent","NetFox"); UG=]8YY!  
String sProperty = "bytes="+nStartPos+"-"; QxN1N^a0  
httpConnection.setRequestProperty("RANGE",sProperty); s2GF*{  
Utility.log(sProperty); 9zS  
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InputStream input = httpConnection.getInputStream(); K[ [6A:  
//logResponseHead(httpConnection); ~%C F3?e6  
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byte[] b = new byte[1024]; <,rOsE6  
int nRead; O`@- b#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =<#G~8WYz  
{ U4^c{KWS  
nStartPos += fileAccessI.write(b,0,nRead); tXH;4K@  
//if(nThreadID == 1) lixM0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cJv/)hRaz  
} {=?(v`88  
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Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; =*jFaj  
//nPos = fileAccessI.write (b,0,nRead); 1kw*Q:  
} 6_])(F3+w.  
catch(Exception e){e.printStackTrace ();} oI[

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} -4sKB>b  
} ]K*R[  
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//打印回应的头信息 T'vI@i9  
public void logResponseHead(HttpURLConnection con) VXWV Pj#  
{ VQ|{Q}  
for(int i=1;;i++) R-9o3TPa  
{ +(92}~RK  
String header=con.getHeaderFieldKey(i); Z#-N$%^F  
if(header!=null) yDK
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); )J> dGIb  
Utility.log(header+" : "+con.getHeaderField(header)); iiMS3ueF  
else y|KQ`;  
break;
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} 'JJKnE zQ  
} E V)H>kM  
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public void splitterStop() 9N'fU),I  
{ *oz#YGNm  
bStop = true; 6bhb_U'f  
} A1-,b.Ni  
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} qe{;EH*  
9QXsbd6  
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/* jaodcT0  
**FileAccess.java <I34@;R c  
*//文件访问(定位，写) 5~?6]=hl  
package NetFox; LdG?kbJ&y  
import java.io.*; O}Pqbx&  
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public class FileAccessI implements Serializable{ |~ fI=1;;x  
6384$mT,S  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 FsJk"$}  
RandomAccessFile oSavedFile; n4S`k%CI  
long nPos; (KyOo,a  
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public FileAccessI() throws IOException JS^DyBXc  
{ 6c-3+,Y"#  
this("",0); B._YT   
} ?8H{AuLB  
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3  
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public FileAccessI(String sName,long nPos) throws IOException hQ<7k'V  
{ =bC'>qw}  
oSavedFile = new RandomAccessFile(sName,"rw"); 7:?\1a  
this.nPos = nPos; FqA4 OU  
oSavedFile.seek(nPos); %AA&n*m  
} HL4=P,'  
HP]5"ziA  
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public synchronized int write(byte[] b,int nStart,int nLen) ]dNNw`1\V  
{ $rcv@-l  
int n = -1; ;K\2/"$QD  
try{ F*@2)  
oSavedFile.write(b,nStart,nLen); iKrk?B<  
n = nLen; we`BqZV  
} SXqB<j$.;  
catch(IOException e) tdxzs_V,-
 
{ ;hDk gp  
e.printStackTrace (); uxD3+Q  
} S!u8JG1  
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}p*|8$#x"  
return n; x6R M)rr  
} E8
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} XyN " Jr  
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u*2
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/* zO"De~[9  
**SiteInfoBean.java v(yJGEf0  
*/
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package NetFox; q`r| DcN~  
v%cCJ SO#  
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public class SiteInfoBean { !xck ~EAS  
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private String sSiteURL; //Site's URL oFP8s[B  
private String sFilePath; //Saved File's Path ugTsI~aE  
private String sFileName; //Saved File's Name E5rV}>(Y  
private int nSplitter; //Count of Splited Downloading File J";N^OR{A%  
hQj@D\}  
} uS0N$4  
public SiteInfoBean() N!~]D[D  
{//nSplitter的缺省值为5 b_nE4>  
//default value of nSplitter is 5 :5CyR3P  
this("","","",5); o-H?q!  
} *1["x;A  
a r8iuwfZ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) z7IJSj1gQI  
{ xD&n'M]  
sSiteURL= sURL; ;G8H'gM07  
sFilePath = sPath; .o`Io[io  
sFileName = sName; RVm-0[m}  
this.nSplitter = nSpiltter; o 7kg.w|  
#&kj>  
/J-'[Mc'D[  
} xkRMg2X.>9  
kqih`E9P7B  
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public String getSSiteURL() 1}la)lC  
{ k^;n$r"i5  
return sSiteURL; wO%lM  
} +U<YM94?  
M;<!C%K>  
J$yq#LBbR@  
public void setSSiteURL(String value) G-)e(u   
{ K0( S%v|,}  
sSiteURL = value; oB5\^V$  
} Ph""[0n%o  
O>pX(DS L  
4@fv%LOQo  
public String getSFilePath() GgY8\>u  
{ #fa,}aj  
return sFilePath; ;GG,Z#\m  
} c|.te]!ds  
rmA?Xlh\  
d*{Cv2A.  
public void setSFilePath(String value) <!RkkU& 6  
{ 7uc\AhOk6  
sFilePath = value; W !j-/ql  
} yC
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{p1`[R&n#  
%dPk,Ylz  
public String getSFileName() &J2UAmB  
{ s9sl*1n1m`  
return sFileName; FtyT:=Kpc  
} |#o' =whTl  
VB*c1i  
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public void setSFileName(String value) M^oL.'  
{ <$-^^b(y  
sFileName = value; hT-^1:N  
} _Sd^/jGpU  
)-!)D  
~xxq.rL"  
public int getNSplitter() <e BmCrJ  
{ {7m2vv?Z  
return nSplitter; h#4n  
} {rMf/RAE  
2{=D)aC$f  
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public void setNSplitter(int nCount) xK_UkB-$i  
{ z9IW&f~~P  
nSplitter = nCount; 9k71h`5  
} `{{6vb^g  
} [ K/l;Zd  
cJ$jU{}  
9*s8%pL  
/* | CFG<]  
**Utility.java y%%VJ}'X!  
*/ >gzM-d  
package NetFox; n(Nu
 
:1qLRr  
K!CVS7  
public class Utility { 5B:"$vC{=  
QEqYqAGzu|  
/Q@4HV  
public Utility() eG(YORkR  
{ /~'C!so[v  
r~T!$Tb  
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} "W6cQsi  
?
9{^gW4|  
//线程睡眠 el5Pe{j'  
public static void sleep(int nSecond) GEy7Vb)  
{ cwvJH&%0  
try{ 5lHt~hB\  
Thread.sleep(nSecond); a({Rb?b  
} wwdmz;0S  
catch(Exception e) P<R^eLZ<&  
{ DI8I'c-P  
e.printStackTrace (); [VXQ&  
} Ao?b1VYy/  
} ktqFgU#rT  
JmCHwyUK?  
//日志 ?0X$ox  
public static void log(String sMsg) @Un/,-ck  
{ UeCi{W  
System.err.println(sMsg); JzN "o'  
} WDxcV%  
`m(ZX\W]  
A94:(z;{  
public static void log(int sMsg) Y_n/rD>  
{ m_Hg!Lg  
System.err.println(sMsg); :a&M]+!  
} ]g$ky.;  
} 46T(1_Xt~  
_Ml?cT/J.O  
;C*2Djb*n  
/* ,?m@Ko7Y  
**TestMethod.java YC%xW*  
*/ dl=)\mSFjF  
package NetFox; fIpS P@$<  
+arh/pd_I  
 j7_,V?5z  
public class TestMethod { r+%3Y:dZE  
=AaF$R  
XO?WxL9k]  
public TestMethod() L>/$l(
 
{ ///xx/weblogic60b2_win.exe zZ-/S~l  
try{ aO1.9!<v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,s%+vD$O^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t9<BQg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }!fIY7gv  
fileFetch.start(); a+z>pV|  
} f1SKOq  
catch(Exception e){e.printStackTrace ();} O2Y|<m  
oVk!C a  
 Yf[Cmn  
} $G0e1)D  
%9zpPrWF  
0aR.ct%  
public static void main(String[] args) .6[8$8c  
{ .sit5
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new TestMethod(); nl2Lqu1  
} t5l<Lm)  
} 4mW$+lzn  
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