http断点续传简单实现（java)

/* 4_=Ja2v8;`  
**SiteFileFetch.java OI/@3"L{  
*/ W<,F28jI3v  
package NetFox; cDkV;$  
import java.io.*; jgu*Y{ocm  
import java.net.*; -"TR\/  
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public class SiteFileFetch extends Thread { W6/ @W  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X(AN)&L[  
long[] nStartPos; //开始位置 \Owp
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long[] nEndPos; //结束位置 v/Pw9j!r;m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +s[\g>i  
long nFileLength; //文件长度 2&LQg=O  
boolean bFirst = true; //是否第一次取文件 $95~5]-nh  
boolean bStop = false; //停止标志 5
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File tmpFile; //文件下载的临时信息 MZ4c{@Tg  
DataOutputStream output; //输出到文件的输出流 .2:\:H~3  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Wch~Yb  
public SiteFileFetch(SiteInfoBean bean) throws IOException )}lRd#V  
{ ^))RM_ic  
siteInfoBean = bean; p<GR SJIk=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !PUZWO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zqySm)o]  
if(tmpFile.exists ()) F2I 5qC/  
{ _ -..~K.|  
bFirst = false; 9";sMB}W*  
read_nPos(); =?Fkn4t  
} \Ad7 Gi~  
else kBWrqZ6  
{ ]`o!1(GA  
nStartPos = new long[bean.getNSplitter()]; Ud%s^A
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nEndPos = new long[bean.getNSplitter()]; =\kMXB  
} d j5hv
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} :QQlI  
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public void run() @R6 ttx  
{ ,J=P,](  
//获得文件长度 hwnJE958L  
//分割文件 ~2*9{  
//实例FileSplitterFetch p3951-D  
//启动FileSplitterFetch线程 FiAY\4  
//等待子线程返回 .K8w8X/3  
try{ Sb&lhgW]c  
if(bFirst) S -&)p@4  
{ 8/%6@Y"Y*  
nFileLength = getFileSize(); W[''Cc.  
if(nFileLength == -1) !7p}C-RZp  
{ 2b@tj 5  
System.err.println("File Length is not known!"); |F$BvCg  
} ,_v|#g@{  
else if(nFileLength == -2) ^q[gx
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{ `FF8ie8L  
System.err.println("File is not access!"); PD[z#T!'  
} ,^s0</ve  
else Tbbz'b;{  
{ Zk-~ar  
for(int i=0;i<nStartPos.length;i++) &m^@9E)S/  
{ KM,|} .@:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); e79KbLV  
} LO%!Z,}   
for(int i=0;i<nEndPos.length-1;i++) o @Z#  
{ Jl<ns,Zg  
nEndPos = nStartPos[i+1]; lHfe<j]  
} i\?*=\a  
nEndPos[nEndPos.length-1] = nFileLength; f>9s!Hpu_  
} ??qq:`s  
} k)\gWPH  
*s4\\Wb=  
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//启动子线程 Zl/<w(f_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *<4Em{rZ5  
for(int i=0;i<nStartPos.length;i++) q?j|K|%   
{ c@(&[/q!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qi
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .i"W8~<e  
nStartPos,nEndPos,i); Qt>>$3]!!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =Ufr^naA  
fileSplitterFetch.start(); Bn?V9TEoO  
} zU5Hb2a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d=O3YNM:v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;^){|9@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _wDS#t;!M  
nEndPos = " + nFileLength); "j<bA8$Vw  
// fileSplitterFetch[nPos.length-1].start(); ,yMU@Vg  
+JyUe    
U Z_'><++  
//等待子线程结束 R*pC.QiB~  
//int count = 0; .3qu9eP  
//是否结束while循环 .Nm su+s  
boolean breakWhile = false; T? ,P*l  
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while(!bStop) h11.'Eej`  
{ %b2oiKSBx?  
write_nPos(); r{?TaiK  
Utility.sleep(500); ,YYVj{~2  
breakWhile = true; 2{,n_w?Wy  
<W)u{KS#TY  
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for(int i=0;i<nStartPos.length;i++) q%YV$$c  
{ R,2P3lv1v@  
if(!fileSplitterFetch.bDownOver) 0ZpFE&  
{ CO+/.^s7}S  
breakWhile = false; (7FW9X;  
break; LtgXShp_!  
} ,FzeOSy'p  
}  Y k7-`  
if(breakWhile) tB7}|jC  
break; 
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//count++; {No L  
//if(count>4) a`Qot  
// siteStop(); XM1`x  
} qO1tj'U<  
\00DqL(Oj`  
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System.err.println("文件下载结束！"); ~V=<3X  
} >x1p%^cA;=  
catch(Exception e){e.printStackTrace ();} aolN<u3G  
} KW^<,qt5w  
!9iGg*0dx  
/$N~O1"0)  
//获得文件长度 ^eYqll/U  
public long getFileSize() VZn=rw  
{ 7%?jL9Vw  
int nFileLength = -1; QnouBrhO  
try{ yF._*9Q3hK  
URL url = new URL(siteInfoBean.getSSiteURL()); FyoEQ%.bI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B$Z3+$hfF  
httpConnection.setRequestProperty("User-Agent","NetFox"); P,DC7\  
?L) !pP]  
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int responseCode=httpConnection.getResponseCode(); gR^>3
n'  
if(responseCode>=400) ~ (On|h  
{ -Ng'<7  
processErrorCode(responseCode); Flxvhl)L  
return -2; //-2 represent access is error 6R;3%-D  
} q"qo.TPh|$  
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String sHeader; Z(>'0]G  
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for(int i=1;;i++) Scm36sT{  
{ qZEoiNH(Tj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); M6r^L6$N  
//Utility.log(in.readLine()); <+#oBN  
sHeader=httpConnection.getHeaderFieldKey(i); kUx&
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if(sHeader!=null) 8e~|.wOL  
{ g?v\!/~(u  
if(sHeader.equals("Content-Length")) ?jQ](i&  
{ :p&!RI(l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); W=B"Q qL  
break; qB]i6*  
} /.Nov  
} fQK"h  
else /2M.~3gQ  
break; rx"s!y{!-  
} RF!a//  
} iZ3W"Vd`b  
catch(IOException e){e.printStackTrace ();} VQI(Vp|  
catch(Exception e){e.printStackTrace ();} E`H$YS3o  
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Utility.log(nFileLength); \'CN  
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}V;+l8  
return nFileLength; zjL.Bhiud  
} B\*@krI@  
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//保存下载信息（文件指针位置） {4aWR><  
private void write_nPos() l%R50aL  
{ x_
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try{ Il@Y|hK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z\ss4  
output.writeInt(nStartPos.length); +y2[msBs  
for(int i=0;i<nStartPos.length;i++) }{9&:!uA  
{ +|Hioq*,t  
// output.writeLong(nPos); U!%!m'  
output.writeLong(fileSplitterFetch.nStartPos); 5Ky#GuC  
output.writeLong(fileSplitterFetch.nEndPos); 2O"P
2(1}v  
} gkBdR +  
output.close();

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} 4n1; Bh$  
catch(IOException e){e.printStackTrace ();} 7`IpBm<  
catch(Exception e){e.printStackTrace ();} yV3^Qtb!  
} ZD#9&q'4<  
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//读取保存的下载信息（文件指针位置） Cp`j/rF  
private void read_nPos() MF3b{|Z  
{ SQ,?N XZ  
try{ <!$:8ls  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (KZHX5T=  
int nCount = input.readInt(); Sw`RBN[ yo  
nStartPos = new long[nCount]; F;lI+^}}  
nEndPos = new long[nCount]; depYqYK7G  
for(int i=0;i<nStartPos.length;i++) WnUweSdW  
{ aq+Y7IR_  
nStartPos = input.readLong(); "jecsqCgK0  
nEndPos = input.readLong(); :f5s4N  
} +QM@VQ  
input.close(); zOEY6lAwI  
} pu!dqF<  
catch(IOException e){e.printStackTrace ();} e7fiGl  
catch(Exception e){e.printStackTrace ();} 3($"q]Y  
} %u^JpC{E  
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private void processErrorCode(int nErrorCode) R8L_J6Kpa  
{ uJR%0E7!  
System.err.println("Error Code : " + nErrorCode); U`Jy!x2m  
} thO ~=
RB  
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!}\4utHY  
//停止文件下载 3bqC\i^[\m  
public void siteStop() m+{K^kr[  
{ =@u 5|:  
bStop = true; z|7z
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for(int i=0;i<nStartPos.length;i++) ~m1P_`T  
fileSplitterFetch.splitterStop(); b96%")  
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} LNl#h  
} 3QSZ ZJ  
//负责部分文件的抓取 xt'tL:d  
**FileSplitterFetch.java o47r<>t  
*/ RO0>I8c1c  
package NetFox; 3Y)PU=  
/MB{Pmk$R  
2Nxm@B` {  
import java.io.*; HIGq%m=-x  
import java.net.*;
;U: {/  
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public class FileSplitterFetch extends Thread { gx03xPeu  
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String sURL; //File URL FLoNE>q  
long nStartPos; //File Snippet Start Position "'^4*o9  
long nEndPos; //File Snippet End Position 04J}UE]Ww  
int nThreadID; //Thread's ID 2#X4G~>#h  
boolean bDownOver = false; //Downing is over n\I#CH0V  
boolean bStop = false; //Stop identical e&MC|US=\  
FileAccessI fileAccessI = null; //File Access interface (qn2xrV  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException k{tMzx]F__  
{ I9o6k?$K  
this.sURL = sURL; bW#@OrsS  
this.nStartPos = nStart; a"/#+=[  
this.nEndPos = nEnd; Y=Z1Tdxa|  
nThreadID = id; 'tN25$=V&W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5#3W5z  
}  I~,G  
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public void run() 0Iud$Lu  
{ 7z\m; 1  
while(nStartPos < nEndPos && !bStop) Id
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{ KucV3-I  
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try{ C ]Si|D
  
URL url = new URL(sURL); 6m.k;'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ES<1tG  
httpConnection.setRequestProperty("User-Agent","NetFox"); GN#<yv$av  
String sProperty = "bytes="+nStartPos+"-"; "I;C;}
!  
httpConnection.setRequestProperty("RANGE",sProperty); o01kYBD  
Utility.log(sProperty); 9/SXs0  
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}],Z;:  
InputStream input = httpConnection.getInputStream(); WqxUXH  
//logResponseHead(httpConnection); *BD=O@  
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*5sBhx  
byte[] b = new byte[1024]; ?^' 7+8C*J  
int nRead; UE _fpq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _u"nvgVz9  
{ zeP}tzQO  
nStartPos += fileAccessI.write(b,0,nRead); M)?dEgU}M  
//if(nThreadID == 1) OE)~yKy  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?EMK8;  
} bG&"9b_c  
NT%W;)6m9  
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Utility.log("Thread " + nThreadID + " is over!"); M-NV_W&M  
bDownOver = true; <1w/hy&mWN  
//nPos = fileAccessI.write (b,0,nRead); h:XzUxL\  
} 8,?v?uE  
catch(Exception e){e.printStackTrace ();} -3Avs9`5  
} [LT^sb  
} |6J ?8y  
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//打印回应的头信息 STfyCtS  
public void logResponseHead(HttpURLConnection con) HhA -[p  
{ |VOg\[f  
for(int i=1;;i++) D+V7hpH-  
{ Mv|ykJoz"  
String header=con.getHeaderFieldKey(i); &a!BD/  
if(header!=null) !.7udYmB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D0Z\Vvy  
Utility.log(header+" : "+con.getHeaderField(header)); 8pM>Co!  
else OYM@szM  
break; =9L$L|W  
} {-9jm%N  
} ^\ ?O4,L  
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public void splitterStop() 0)YbI!  
{ Nd:R" p*8  
bStop = true; \u`)kJ5o1  
} :Ud[f`t  
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} #LcrI  
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/* +]>+a<x*%  
**FileAccess.java 39e;  
*//文件访问(定位，写) ,p{`pma  
package NetFox; .
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import java.io.*; 5OM?3M  
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public class FileAccessI implements Serializable{ N)R[6u}  
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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 XXmE+aI  
RandomAccessFile oSavedFile; m!XI{F@x  
long nPos; )j6eE+gF  
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public FileAccessI() throws IOException TL= Y
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{ RKd  
this("",0); ydl jw  
} 4kp im  
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public FileAccessI(String sName,long nPos) throws IOException maMHZ\Q  
{ {hSGv
  
oSavedFile = new RandomAccessFile(sName,"rw"); /rB{[zk  
this.nPos = nPos; )!9Ifk0KH  
oSavedFile.seek(nPos); >(
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} ,7]k fB  
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5`^o1nGO'  
public synchronized int write(byte[] b,int nStart,int nLen) {mYP<NBT  
{ [c K^+s)N  
int n = -1; !}TMiCK  
try{ =1/NFlt8  
oSavedFile.write(b,nStart,nLen); g]mtFrP  
n = nLen; s}M= oe  
} cl[!`Z  
catch(IOException e) #~:P}<h  
{
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e.printStackTrace (); wn+FTqj  
} BJjx|VA+  
X[C3&NX#_  
}6RT,O g  
return n; 8$P>wCK\l  
} .r|*Ch#;P  
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} .;/L2Jv  
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/* ,1n >U?5  
**SiteInfoBean.java vvu<:16  
*/ 2f,B$-#  
package NetFox; -xmf'c9P  
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-
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public class SiteInfoBean { $FM' 3%B[  
;~ 4k7Uz  
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private String sSiteURL; //Site's URL jdRq6U^  
private String sFilePath; //Saved File's Path ;Kxbg>U  
private String sFileName; //Saved File's Name OTvROJP  
private int nSplitter; //Count of Splited Downloading File a^nAZ  
uq7T{7~<  
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public SiteInfoBean() V}8$p8#<@  
{//nSplitter的缺省值为5 5vp|?-\h>  
//default value of nSplitter is 5 A;K(J4y*  
this("","","",5); g9tu%cIkR  
} Eyh|a.)-  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O??vm?eo  
{ 'E]A.3-Mt  
sSiteURL= sURL; Ng<1Sd|MV  
sFilePath = sPath; ~&G4)AM  
sFileName = sName; $`Nd?\$  
this.nSplitter = nSpiltter; '8`T|2  
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} Y)HbxFF`/  
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public String getSSiteURL() Fxd{ Zk`  
{
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return sSiteURL; ))#'4  
} TYS\95<  
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public void setSSiteURL(String value) T{MC-j _T9  
{ /lD?VE  
sSiteURL = value; jp<VK<s]  
} iLq#\8t^  
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public String getSFilePath() ;b~~s.+  
{ B!,yfTk]  
return sFilePath; is#8R:7.:  
} D5A=,\uk  
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public void setSFilePath(String value) hY8#b)l~lu  
{  WR.x&m
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sFilePath = value; u}jrfKdE  
} n.$(}A  
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public String getSFileName() H~9=&p[Q  
{ ?b$3ob"  
return sFileName; =Sxol>?t  
} !Tfij(91  
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br,  
public void setSFileName(String value) i^|@"+  
{ 4,}GyVJFb`  
sFileName = value; jMU9{Si  
} }B)jq`a?|\  
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public int getNSplitter() 4#rAm"H  
{ F$Pp]"82'm  
return nSplitter; K3ukYR  
} $Ub}p[L  
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public void setNSplitter(int nCount) h5onRa*
7  
{ J+2R&3;_O  
nSplitter = nCount; *8\(FVyG^  
} @-6?i)  
} hZuYdV{'h  
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/* "{F;M{h$},  
**Utility.java 'Z7P  
*/ 9*_uCPR  
package NetFox; 4 X`^{~  
<-)9
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public class Utility { f5?hnt`m  
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public Utility() @hT;Bo2G]  
{ _i@x@:_l  
1q!sKoJ<  
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} )73DT3-0$  
lG]GlgSs  
//线程睡眠 WEC-<fN|Y\  
public static void sleep(int nSecond) |h,FUj<r  
{ /=M.-MU2
 
try{ v MWC(m  
Thread.sleep(nSecond); "k
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} ~&~C#yjg1  
catch(Exception e) FOp_[rR   
{ d| \#?W&  
e.printStackTrace (); cdsQ3o  
} 9p<:LZd~  
} LXxl?D  
lIl9ypikg  
//日志 7.|S>+Q  
public static void log(String sMsg) A_Gp&acs$  
{ P%!q1`Eke(  
System.err.println(sMsg); Mcb<[~m  
} ;U7t  
)/TVJAJ  
@7|)RSBQz  
public static void log(int sMsg) M,{<TpCx  
{ YHh u^}|jQ  
System.err.println(sMsg); yHw!#gWM  
} bV7QVu8  
} rxkBg0Z`a  
*]9XDc]{j1  
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/* Prt#L8  
**TestMethod.java fiqj;GW  
*/ ]}_,U!`8  
package NetFox; "0Y&~q[=  
"GBUQ}  
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public class TestMethod { YD+QX@  
d.1Q~&`  
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public TestMethod() ke</x+\F  
{ ///xx/weblogic60b2_win.exe |vN$"mp^a  
try{ B)d@RAk  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 73#9NZR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {lKEZirO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -9i+@%{/  
fileFetch.start(); :\T_'Shq  
} /K&wr6  
catch(Exception e){e.printStackTrace ();} 2c*2\93>  
C9+Dw#-fV  
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} ?/L1tX)  
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public static void main(String[] args) #|D:f~"d3  
{ 4w2L?PDMi  
new TestMethod(); EkV!hqs
*  
} l?N`V2SuR  
} o}W7.7^2  
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