http断点续传简单实现（java)

/* fZ6lnZ  
**SiteFileFetch.java xW*L^97 ;  
*/ MyZ@I7Fb,  
package NetFox; ZbJzf]y:6  
import java.io.*; yG'5up  
import java.net.*; Ip]-OVg  
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public class SiteFileFetch extends Thread { AW@I,  
#_{3W-35*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w">XI)*z  
long[] nStartPos; //开始位置 <5MnF  
long[] nEndPos; //结束位置 +)Tt\Q%7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xZt]s3?  
long nFileLength; //文件长度 tWVbD%u^  
boolean bFirst = true; //是否第一次取文件 [E_6n$w  
boolean bStop = false; //停止标志 XA}!  
File tmpFile; //文件下载的临时信息 ']1j Mn  
DataOutputStream output; //输出到文件的输出流 )'(7E$d  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） hA6!F#1  
public SiteFileFetch(SiteInfoBean bean) throws IOException uJ,>Y# ?  
{ XoM+"R"  
siteInfoBean = bean; Oqeoh<y!\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g$eb@0$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZRO   
if(tmpFile.exists ()) 7Zp'}Om<I  
{ \I; lgz2  
bFirst = false; tUl#sqN_{  
read_nPos(); LBT
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} s"`uE$6N  
else ^R\0<\'  
{ LhC%`w  
nStartPos = new long[bean.getNSplitter()]; v-2O{^n  
nEndPos = new long[bean.getNSplitter()]; vMK
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} {E!ie{~  
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} NK]X="`  
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public void run() TTpK8cC  
{ #R<4K0Xan  
//获得文件长度 Epsc2TuH7  
//分割文件 s2)a8<  
//实例FileSplitterFetch l)GV&V  
//启动FileSplitterFetch线程 Ee;&;Q,O.z  
//等待子线程返回 k$?zh$  
try{ 8r(S=dA  
if(bFirst) i]gF 6:&  
{ L=ZKY  
nFileLength = getFileSize(); K.G}*uy  
if(nFileLength == -1) 4FEOV,n  
{ cf?*6q?n  
System.err.println("File Length is not known!"); ;1^_.3  
} {tMpI\>S  
else if(nFileLength == -2) w+gA3Dg  
{ Y s[JxP  
System.err.println("File is not access!"); Zp]{e6J  
} +{N LziO  
else =xScHy{$  
{ =8[4gM+  
for(int i=0;i<nStartPos.length;i++) lDd+.44V:  
{ Se+sgw_"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); v.H00}[.  
} Wfgs[  
for(int i=0;i<nEndPos.length-1;i++) wmdvAMN  
{ udM<jY]5p  
nEndPos = nStartPos[i+1]; XZhuV<  
} iZ2|/hnw  
nEndPos[nEndPos.length-1] = nFileLength; 6 ?FF!x  
} =FQ]eb*  
} !mH2IjcL  
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//启动子线程 $EHAHNL?Lx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VU`aH9g3(  
for(int i=0;i<nStartPos.length;i++) ykc$B5*  
{ yg\bCvL&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =7pLU+ u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), FI{9k(  
nStartPos,nEndPos,i); ,5Jq ZD  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
#n5q$  
fileSplitterFetch.start(); k/hE68<6i  
} CS2AKa@`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qwJe
eax  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0G?0 Bo  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /H&:  
nEndPos = " + nFileLength); )MqF~[k<-  
// fileSplitterFetch[nPos.length-1].start(); @1ZLr  
?kvkkycI  

#R v&b@K  
//等待子线程结束 R4v)}`x  
//int count = 0; EeC5HgIU'C  
//是否结束while循环 ;|&Ak_I2G  
boolean breakWhile = false; YFgQ!\&59  
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while(!bStop) 4HEp}Y"}V  
{ vk:@rOpl  
write_nPos(); r
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Utility.sleep(500); M0g!"0?  
breakWhile = true; ~E&drl\  
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for(int i=0;i<nStartPos.length;i++) &niROM,;K  
{ 7c$;-O  
if(!fileSplitterFetch.bDownOver) v[WbQ5AND  
{ a}eM ny  
breakWhile = false; 5#/"0:2  
break; 9Y&,dBj+  
} uCuXY#R+  
} e 5U<nf  
if(breakWhile) aGvD  
break; BtDi$d%'  
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//count++; "J^M@k\!  
//if(count>4) h3Kv0^{  
// siteStop(); r!+-"hS!  
} `r;e\Cp  
HI6;=~[  
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System.err.println("文件下载结束！"); 3{B`[
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} uV?[eiezD0  
catch(Exception e){e.printStackTrace ();} R06q~>  
} sXxF5&AF0  
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//获得文件长度 7RNf)nz  
public long getFileSize() =;Gy"F1 dp  
{ "pTyQT9P  
int nFileLength = -1; "Wd?U[[  
try{ C'3/B)u}l  
URL url = new URL(siteInfoBean.getSSiteURL()); tAH,3Sz( /  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j&)"a,f  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6KP"F[8I  
6-C9[[g<  
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int responseCode=httpConnection.getResponseCode(); Hp;Dp!PLa  
if(responseCode>=400) OV ~|@{6T  
{ i~ D,  
processErrorCode(responseCode); @(2DfrC  
return -2; //-2 represent access is error "QA <5P  
} u(V4KUk  
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String sHeader; ?z>Zs
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for(int i=1;;i++) $$+6=r}  
{ ukBj@.~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e(E6 t_  
//Utility.log(in.readLine()); 3Tv;<hF  
sHeader=httpConnection.getHeaderFieldKey(i);
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if(sHeader!=null) .hW_P62\#  
{ A|p O  
if(sHeader.equals("Content-Length")) 1
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{ _
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %9hzz5#  
break; J2VhheL`J  
} {'P7D4w  
} H: q(T >/w  
else dE9xan  
break; OpeK-K
 
} _ Js& _d  
} FaO=<jYi  
catch(IOException e){e.printStackTrace ();} HVG9 C$  
catch(Exception e){e.printStackTrace ();} AK%2#}k.  
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Utility.log(nFileLength); to@ O  
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return nFileLength; pcIJija:  
} v~i/e+.h>y  
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//保存下载信息（文件指针位置） ,&$=2<Dx  
private void write_nPos() 9qxB/5d_  
{ w]Z*"B&h  
try{ jeM %XI  
output = new DataOutputStream(new FileOutputStream(tmpFile)); n|5+HE4@  
output.writeInt(nStartPos.length); 4r5trquC  
for(int i=0;i<nStartPos.length;i++) d7Lna^  
{ O}\$E{-  
// output.writeLong(nPos); 8+m;zvDSU  
output.writeLong(fileSplitterFetch.nStartPos); =w='qjh  
output.writeLong(fileSplitterFetch.nEndPos);
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} K
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output.close(); V~p/P  
} ZnDI J&S  
catch(IOException e){e.printStackTrace ();} 1?s]nU  
catch(Exception e){e.printStackTrace ();} Sgp$B:  
} lN"%~n
?  
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//读取保存的下载信息（文件指针位置） G/ToiUY  
private void read_nPos() ??Zh$^No:  
{ Nb/W+& y  
try{ &t1?=F,]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9A0wiKp  
int nCount = input.readInt(); 9C[i#+_3M  
nStartPos = new long[nCount]; B;.]<k'3  
nEndPos = new long[nCount]; `0a=A#]1o  
for(int i=0;i<nStartPos.length;i++) /Zs;dam  
{ ./nq*4=  
nStartPos = input.readLong(); QV/o;  
nEndPos = input.readLong(); WO{V,<;  
} hd*bPj;  
input.close(); Kp[
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} Ul#||B .c{  
catch(IOException e){e.printStackTrace ();} 6}bUX_!&s  
catch(Exception e){e.printStackTrace ();} ht _fbh(l  
} P)bS ;w\(Y  
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private void processErrorCode(int nErrorCode) OrN>4S  
{ (}1 gO  
System.err.println("Error Code : " + nErrorCode); .9X
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} &c<0g`x  
a?#v,4t^  
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//停止文件下载 aq/'2U 7  
public void siteStop() tHgn-Dhzr  
{ ge*(w{|x  
bStop = true; =?fxPT[1K  
for(int i=0;i<nStartPos.length;i++) r9[{0y!4  
fileSplitterFetch.splitterStop(); #4uuT
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} FJ]BB4 K  
} J+oK:tzt8  
//负责部分文件的抓取 M(>"e*Pi  
**FileSplitterFetch.java [7d>c  
*/ 26n+v(re  
package NetFox; VNKtJmt  
@64PdM!L  
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import java.io.*; t# cm|  
import java.net.*; yhnhORSY;  
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public class FileSplitterFetch extends Thread { zq ;Y
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String sURL; //File URL %-C  
long nStartPos; //File Snippet Start Position pRS+vV3  
long nEndPos; //File Snippet End Position sp%EA=: E  
int nThreadID; //Thread's ID Jv*[@ -.k  
boolean bDownOver = false; //Downing is over rGjP|v@3^  
boolean bStop = false; //Stop identical iDp'M`(6h  
FileAccessI fileAccessI = null; //File Access interface ico%_fp  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @wa2Z  
{ J,@SSmJ`  
this.sURL = sURL; ' fXBWi6  
this.nStartPos = nStart; s^:8bFn9$  
this.nEndPos = nEnd; '~-JR>  
nThreadID = id; Af'L=0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Z)=S. )  
} ')!+>b(P  
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public void run() pO^gooV\  
{ b|7c]l  
while(nStartPos < nEndPos && !bStop) %"#%/>U4  
{ 5\hJ&  
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try{ xqV>m  
URL url = new URL(sURL); C*O648yz[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 
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httpConnection.setRequestProperty("User-Agent","NetFox"); !YJfP@"e6r  
String sProperty = "bytes="+nStartPos+"-"; =*K~U# uoC  
httpConnection.setRequestProperty("RANGE",sProperty); |^z?(?w  
Utility.log(sProperty); VXr'Z  
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InputStream input = httpConnection.getInputStream(); Vaj4p""\F  
//logResponseHead(httpConnection); a~#MMl  
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byte[] b = new byte[1024]; cL/6p0S  
int nRead; fb8"hO]s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?9jl8r>  
{ `$V7AqX(  
nStartPos += fileAccessI.write(b,0,nRead); V4c$V]7  
//if(nThreadID == 1) >GRL5Iow  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e+Qq a4  
} Z' cQ< f  
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Utility.log("Thread " + nThreadID + " is over!"); 2=?/$A9p  
bDownOver = true; O3U6"{yJ)  
//nPos = fileAccessI.write (b,0,nRead); :z=C   
} ^Rgm3?7  
catch(Exception e){e.printStackTrace ();} "S#}iYp  
} R~9\mi5^UH  
} {z":hmt  
N =k}"2_=  
/]0-|Kg+R  
//打印回应的头信息 )HLe8:PG~  
public void logResponseHead(HttpURLConnection con) ?`& l Y  
{ M]\p9p(_  
for(int i=1;;i++) .u
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{ P F#X8+&J  
String header=con.getHeaderFieldKey(i); (``EBEn  
if(header!=null) =P* YwLb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \FVm_)  
Utility.log(header+" : "+con.getHeaderField(header)); o;.6Y `-fJ  
else x6=Yt{  
break; ;QMRm<CLV  
} Gp}:U>V)  
} #;4afj:2g  
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public void splitterStop() UG)XA-ez  
{ a[Q\8<  
bStop = true; @I\&-Z ^  
} gEWKM(5B}  
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} {|Ew]Wq  
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/* <IiX_*  
**FileAccess.java i5oV,fiZo  
*//文件访问(定位，写) :?!kZD!  
package NetFox; ([Gb]0  
import java.io.*; H@!\?5
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public class FileAccessI implements Serializable{ Vl91I+Ev  
SV-M8Im73z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 QG~4<zy  
RandomAccessFile oSavedFile; $UgQ1Qc  
long nPos; 2(_+PQ6C=  
b<]--\  
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public FileAccessI() throws IOException F*&A=@/3  
{ UIhU[
f]  
this("",0); N>Dr z  
} 6EHYIN^D  
/}%$fB  
p i;,?p-  
public FileAccessI(String sName,long nPos) throws IOException Idq&0<I  
{ BhO*Pfs  
oSavedFile = new RandomAccessFile(sName,"rw"); ,4RmT\%T  
this.nPos = nPos; 80i-)a\n  
oSavedFile.seek(nPos); 7d44i  
} iX3Y:   
gBF2.{"^  
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public synchronized int write(byte[] b,int nStart,int nLen) fjc8@S5x9j  
{ z_)`='&n  
int n = -1;
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try{ Ch3{q/-g  
oSavedFile.write(b,nStart,nLen); &$\B&Hp@  
n = nLen; E?L^
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} ZGstD2N$  
catch(IOException e) .@#GNZe  
{ 'qhi8=*  
e.printStackTrace (); \I!C`@0  
} [M:ag_rm+f  
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return n; pN-l82]'  
} Bz&6kRPv  
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} d&!;uzOx  
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/* {FIr|R&  
**SiteInfoBean.java ~OuKewr\  
*/ !=C74$TH  
package NetFox; wt8?@lJ"/  
q
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public class SiteInfoBean { @ m' zm:  
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private String sSiteURL; //Site's URL  j-H2h  
private String sFilePath; //Saved File's Path ,Z2fVz~9  
private String sFileName; //Saved File's Name k&|#(1CFY  
private int nSplitter; //Count of Splited Downloading File nnv&~
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k9V#=,K0  
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public SiteInfoBean() 8'niew 5d  
{//nSplitter的缺省值为5 y:C=Ni&,"  
//default value of nSplitter is 5 w=dTa5  
this("","","",5); *%[L @WF  
} 3RwDIk?>%  
\yQs[l%J  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cph&\ V2jt  
{ SFj:|S=v6j  
sSiteURL= sURL; #@quuiYq  
sFilePath = sPath; <)f1skJsP  
sFileName = sName; -&AgjzN!  
this.nSplitter = nSpiltter; 12D>~#J  
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2{-};
 
} 4
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public String getSSiteURL() +>w %j&B  
{ p!b_tyJ  
return sSiteURL; a9+l:c@  
} <Mt>v2a3Y  
r5k{mV+  
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public void setSSiteURL(String value) L0sb[:'luz  
{ ,aA%,C.0U
 
sSiteURL = value; <k41j=d  
} Ct8}jg
"  
*$+:Cbe-F  
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public String getSFilePath() ;J]
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{ Eku+&f@RB  
return sFilePath; Vo G`@^s  
} 8p91ni'  
bL6, fUS  
w&b?ze{  
public void setSFilePath(String value) :u ruC
  
{ R6xJw2;_  
sFilePath = value; !4?QR  
} h;+bHrKji  
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v`G[6Z  
public String getSFileName() ees^
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{ w~}*MsB  
return sFileName; 9fj8r3 F#  
} Xb/W[rcs  
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::&hfHR*P  
public void setSFileName(String value) lDK<gd  
{ t XbMP  
sFileName = value; rQrh(~\:  
} ,; 81FK  
cBGR%w\t%  
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public int getNSplitter() 8c1ma  
{ Ig.9:v`  
return nSplitter; o 9?#;B$  
} [f8mh88r  
)C1ihm!7\  
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public void setNSplitter(int nCount) gO9\pI2  
{ K:<0!C!  
nSplitter = nCount; :m{;<LRV  
} Bh%Yu*.f  
} ah8xiABa  
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/* u3VSS4RG%  
**Utility.java d[t+iBP;)  
*/ xGBp+j1H  
package NetFox; ;oT!\$Mu  
+eIX{J\s  
$Fr>'H+i  
public class Utility { xO` `X<  
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public Utility() ]K^#
'[  
{ ?T (@<T  
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} ej^pFo  
'|jN!y^2p  
//线程睡眠 ?Z{:[.  
public static void sleep(int nSecond) >'MT]@vez  
{ 0CtPq`!  
try{ \-2O&v'}  
Thread.sleep(nSecond); ]?/7iM  
} :jP4GCxU|  
catch(Exception e) %s(Ri6R&  
{ D'UYHc{  
e.printStackTrace (); =eB^(!M  
} \0'0)@uziQ  
} |GqKa  
Mu>WS)1lS  
//日志 4Ww.CkRG  
public static void log(String sMsg) ^j)0&}fB  
{ 6.0/asN}  
System.err.println(sMsg); !=t.AgmL  
} kH9fK80  
hp<NVST  
K[G=J  
public static void log(int sMsg) rO;Vr},3\%  
{ .~L^h/)Gjy  
System.err.println(sMsg); 'UN 'gXny  
} 08pG)_L  
} ?A\[EI^  
~a RK=i$F  
9U=~t%qW$  
/* ?yq $ >Qba  
**TestMethod.java YS|Ve*t(L=  
*/ 7L"Pe'Hw  
package NetFox; +bC=yR  
r'/H3  
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public class TestMethod { {r.yoI4e  
9[7Gxmf  
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public TestMethod() lA1l  
{ ///xx/weblogic60b2_win.exe `VzjXJw  
try{ _=s{,t &u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /E|Ac&Qk  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7Ns1b(kU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _1sjsGp>  
fileFetch.start(); JS:AHJSz  
} XSDudL  
catch(Exception e){e.printStackTrace ();} _+?v'#  
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]DV=/RpJ9B  
} +:#x!i;W8[  
v_s(  
G
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public static void main(String[] args) QaAWO  
{ 'nR'o /!  
new TestMethod(); "7RnT3  
} .V.x0  
} nxZ[E.-\  
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