http断点续传简单实现（java)

/* o'}Z!@h  
**SiteFileFetch.java [r< Y0|l,m  
*/ %!hA\S  
package NetFox; ()IgSj?,  
import java.io.*; #
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import java.net.*; qP.VK?jF|  
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public class SiteFileFetch extends Thread { 1p5q}">z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 'w$we6f  
long[] nStartPos; //开始位置 apWrcaj  
long[] nEndPos; //结束位置 @Oc}\Rg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 N|#x9mE  
long nFileLength; //文件长度 V9 t:JY  
boolean bFirst = true; //是否第一次取文件 ojs/yjvx  
boolean bStop = false; //停止标志 E":":AC#  
File tmpFile; //文件下载的临时信息 k}a!lI:  
DataOutputStream output; //输出到文件的输出流 ?B31t9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _@3O`
 
public SiteFileFetch(SiteInfoBean bean) throws IOException 'A@Oia1;{  
{ 9mtC"M<   
siteInfoBean = bean; %RF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); BOcEL%+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )UU6\2^  
if(tmpFile.exists ()) &(U=O?r7  
{ Ita!07  
bFirst = false; M(f*hOG{Y  
read_nPos(); ha'm`LiX  
} tp3N5I  
else
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{ a{YVz\?d}  
nStartPos = new long[bean.getNSplitter()]; R$'nWzX#  
nEndPos = new long[bean.getNSplitter()]; sBG(CpQ  
} gYIYA"xN`  
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} K1:)J.ca_  
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public void run() +?eAaC7s  
{ K?<Odw'k  
//获得文件长度 ov.rHVeI  
//分割文件 L7'X7WYf&  
//实例FileSplitterFetch 
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//启动FileSplitterFetch线程 \}&w/.T  
//等待子线程返回 dufHd  
try{ F,$$N>  
if(bFirst) AyXKhj#Ml  
{ 5N}|VGN  
nFileLength = getFileSize(); BP><G^  
if(nFileLength == -1) y,eoTmaI  
{ {*  _ W  
System.err.println("File Length is not known!"); uPD_s[  
} \nt'I;f  
else if(nFileLength == -2) WED7]2>  
{ gM]/Y6*$b  
System.err.println("File is not access!"); \
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} xg!\C@$  
else VH*(>^OfF  
{ 5 `mVe0uI  
for(int i=0;i<nStartPos.length;i++) i; uM!d}  
{ 6m<9^NT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;{u#~d}  
} ( I~XwP&  
for(int i=0;i<nEndPos.length-1;i++) )u:8Pv  
{ 6q7Y`%j
 
nEndPos = nStartPos[i+1]; iFT3fP'> 5  
} 4SO{cst  
nEndPos[nEndPos.length-1] = nFileLength; : .e
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} *J-jr8&  
} N^j''siB  
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#.K&]OV/88  
//启动子线程 AYtcN4\/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U}5KAi 9Z  
for(int i=0;i<nStartPos.length;i++) |-?b)yuAz  
{ c'4 \F9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x?$Y<=vT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #rC+13  
nStartPos,nEndPos,i); P=i |{vv(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (bXp1*0 ;  
fileSplitterFetch.start(); 7[,f;zG  
} unB "dE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XX+rf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'Pn`V{a  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W#/Ol59  
nEndPos = " + nFileLength); +1A<kJ  
// fileSplitterFetch[nPos.length-1].start(); .h }D%Qa  
ZuON@(  
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//等待子线程结束 0 N^V&k   
//int count = 0; D{}\7qe  
//是否结束while循环 eS+LFS7*k  
boolean breakWhile = false; =swcmab;  
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while(!bStop) e1a%Rj~  
{ U%olH >1K  
write_nPos(); [C#pMLp,~  
Utility.sleep(500); =1uI >[aN  
breakWhile = true; Np)!23 "  
{RO=4ba{J  
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for(int i=0;i<nStartPos.length;i++) nhxl#  
{ tt91)^GdYa  
if(!fileSplitterFetch.bDownOver) od|.E$B  
{ vDL/PXNC  
breakWhile = false; r-uIFhV^  
break; g==^ioS}*  
} ZaV@}=Rd8  
} w|ei*L  
if(breakWhile) [!$>:_Vq/  
break; c}cboe2  
<;K/Yv'{r  
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//count++; w, wt<@}  
//if(count>4) WNi<|A#T{  
// siteStop();  #pK)  
} Sn,z$-;h;  
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System.err.println("文件下载结束！"); M?`06jQD.  
} n40Z  
catch(Exception e){e.printStackTrace ();} Plv+mb  
} w9BH>56/"  
2y,wN"qH*  
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//获得文件长度 4]R3*F  
public long getFileSize()
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{ .})8gL7V  
int nFileLength = -1; YWdvL3Bgk,  
try{ _X/`4 G  
URL url = new URL(siteInfoBean.getSSiteURL()); z@j&vW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }8e%s;C  
httpConnection.setRequestProperty("User-Agent","NetFox"); lX7^LB  
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int responseCode=httpConnection.getResponseCode(); i=UJ*c  
if(responseCode>=400) )}v2Z3:  
{ + u+fEg/A  
processErrorCode(responseCode); x(~
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return -2; //-2 represent access is error G[ea@u$?  
} /cn_|DwN5  
k[m-"I%ZFX  
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String sHeader; Y_B(R  
j.*}W4`Q_  
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for(int i=1;;i++) 04TV./uA  
{ 9|,AhyhO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (@9-"W  
//Utility.log(in.readLine()); `x3c},'@k  
sHeader=httpConnection.getHeaderFieldKey(i); &~EOM  
if(sHeader!=null) :Vc9||k  
{ aDESO5  
if(sHeader.equals("Content-Length")) O!jCQ{ T  
{ :n4x}%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @nK08Kj-  
break; xOH@V4z:  
} jLg4_N1SD  
} G.8ZISN/  
else W:G*t4i  
break; R<U<Y'Y  
} -q27N^A0  
} Ym6[~=~EK  
catch(IOException e){e.printStackTrace ();} |BR&p)7)  
catch(Exception e){e.printStackTrace ();} xe'*%3-v)  
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Utility.log(nFileLength); #<:khs6  
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return nFileLength; :1Ay_b_J  
} 4T"P#)z  
*(J<~:V?  
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//保存下载信息（文件指针位置） .W\Fa2}%av  
private void write_nPos() W=drp>Uj  
{
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try{ ,h"M{W$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q6E80>  
output.writeInt(nStartPos.length); 4U3T..wA  
for(int i=0;i<nStartPos.length;i++) d?JVB  
{ 1x]G/I*  
// output.writeLong(nPos); /}wGmX! -!  
output.writeLong(fileSplitterFetch.nStartPos); ygHNAQG~  
output.writeLong(fileSplitterFetch.nEndPos); &f$jpIyVX  
} !#QD;,SE+  
output.close(); :Fh*4 &Z  
} LF8B5<[O  
catch(IOException e){e.printStackTrace ();} H)Yv_gT  
catch(Exception e){e.printStackTrace ();} AyWCb  
} 2B|3`trY4x  
#*fB~Os:  
i
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//读取保存的下载信息（文件指针位置） YB[P`Muj  
private void read_nPos() LS;kq',  
{ Xv9CD  
try{ };
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *ZHk^d:  
int nCount = input.readInt(); V'8 (}(s/  
nStartPos = new long[nCount]; 7ORwDR,`5  
nEndPos = new long[nCount]; <5 okwcJ^  
for(int i=0;i<nStartPos.length;i++) O1QHG'00  
{ YS9|J=!~  
nStartPos = input.readLong(); D .E
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nEndPos = input.readLong(); {"s8X(#_sC  
} 1cPi>?R:  
input.close(); Z|u_DaSrr|  
} w] VvH"?  
catch(IOException e){e.printStackTrace ();} OF)X(bi4j  
catch(Exception e){e.printStackTrace ();} fYpy5vc-dm  
} q^gd1K<N  
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private void processErrorCode(int nErrorCode) FBe1f1 sm  
{ y<Z8+/f`f  
System.err.println("Error Code : " + nErrorCode); 6d,"GT  
} f?)qZ
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//停止文件下载 ~&g:7f|X  
public void siteStop() D+RG,8Ht  
{ W /IyF){  
bStop = true; e_Y>
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for(int i=0;i<nStartPos.length;i++) Gz`Zp "i%0  
fileSplitterFetch.splitterStop(); c#_%|gg  
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} fZgZ  
} Te;`-EL  
//负责部分文件的抓取 p!=/a)4X  
**FileSplitterFetch.java 5ES$qYN  
*/ /#blXI  
package NetFox; p< XjiRq  
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import java.io.*; :[Fwc  
import java.net.*; )V3G~p=0  
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public class FileSplitterFetch extends Thread { }ZV$_  
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String sURL; //File URL g8^$,  
long nStartPos; //File Snippet Start Position qz?9:"~$C  
long nEndPos; //File Snippet End Position {2-w<t  
int nThreadID; //Thread's ID $H?v  
boolean bDownOver = false; //Downing is over 
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boolean bStop = false; //Stop identical e<q;` H  
FileAccessI fileAccessI = null; //File Access interface %ePInpb  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &}6=V+J;  
{ ;vuok]@  
this.sURL = sURL; I6\l6o  
this.nStartPos = nStart; [(]uin+9Q  
this.nEndPos = nEnd; 2: fSn&*/>  
nThreadID = id; (T,ST3{*k  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 znD0&CS9q  
} lBl`R|Gt  
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public void run() (tys7og$'  
{ _K'YaZTa;~  
while(nStartPos < nEndPos && !bStop) ,9=5.+AJ  
{ [i\K#O +f  
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try{ g\d|/HVK  
URL url = new URL(sURL); ge*f<#|0U-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u`7\o~$  
httpConnection.setRequestProperty("User-Agent","NetFox"); TtlZum\  
String sProperty = "bytes="+nStartPos+"-"; 7h0LR7  
httpConnection.setRequestProperty("RANGE",sProperty); [8![UcMq  
Utility.log(sProperty); p%8y!^g  
/ F9BbG{  
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InputStream input = httpConnection.getInputStream(); ] vQn*T"^  
//logResponseHead(httpConnection); kk& ([xqU  
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byte[] b = new byte[1024]; *$
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int nRead; R FWJ ZN"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #Mrof9  
{ L`3x0u2  
nStartPos += fileAccessI.write(b,0,nRead); b@"#A8M  
//if(nThreadID == 1) Nn>Oq+:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ??)IPRv?yF  
} \\xoOA.  
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Utility.log("Thread " + nThreadID + " is over!"); &i$p5  
bDownOver = true; LS <\%A}  
//nPos = fileAccessI.write (b,0,nRead); s +"?j  
} OjFB_ N  
catch(Exception e){e.printStackTrace ();} ch!/k  
} "`s{fy~mV  
} e+Vn@-L;  
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//打印回应的头信息 V\vt!wBcB  
public void logResponseHead(HttpURLConnection con) <>%2HRn<u  
{ M*<Ee]u  
for(int i=1;;i++) AhWcJD]  
{ 2Jm#3zFYz3  
String header=con.getHeaderFieldKey(i); E.45s? r  
if(header!=null) `r+zNJ@q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~nDbWv"  
Utility.log(header+" : "+con.getHeaderField(header)); k>SPtiAs  
else !59u z4  
break; =~yRgGwJ  
} ?$J#jhR?  
} QbrR=[8b  
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#%5[8~&  
public void splitterStop() 0w<vc}{t  
{ ;auT!a~a#  
bStop = true; fAYp\k  
} crTRfqF  
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} Qa>t$`o`  
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&!N9.e:-]  
/* %0&59q]LM  
**FileAccess.java J;wDvt]]1  
*//文件访问(定位，写) M-7^\wXTA  
package NetFox; !-B$WAV  
import java.io.*; B:oE&Ahh{  
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public class FileAccessI implements Serializable{ = Zi'L48  
1#}}:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &65I 6  
RandomAccessFile oSavedFile; e>J.r("f  
long nPos; @KJ~M3d0l  
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public FileAccessI() throws IOException zpgRK4p,I"  
{ xaI)d/  
this("",0); .:r l<.  
} [$]qJ~kz  
@}\wec_  
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public FileAccessI(String sName,long nPos) throws IOException $/J4?Wik  
{ ;x,yGb`  
oSavedFile = new RandomAccessFile(sName,"rw"); ,)?!p_*@:  
this.nPos = nPos; 4m1@lnjp  
oSavedFile.seek(nPos); N.'-9hv  
} Ky[s&>02  
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public synchronized int write(byte[] b,int nStart,int nLen) 4p<c|(f#  
{ )kIZmQ|f1  
int n = -1; E\1e8Wyh  
try{ 1 EL#T&  
oSavedFile.write(b,nStart,nLen); 4LXC;gZ  
n = nLen; #n_t5 O[  
} yByxy-~  
catch(IOException e) Mh"iyDGA  
{ <H,E1kGw9  
e.printStackTrace (); bUU\bc  
} br;~}GR_h
 
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return n; 3;?DKRIcX  
} I+eKuWB  
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} ROi_k4Fj  
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ech1{v\B|  
/* U{52bH<  
**SiteInfoBean.java AB+HyZ*//  
*/ *E|#g  
package NetFox; zX8'OoEH*9  
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public class SiteInfoBean { QCJf   
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private String sSiteURL; //Site's URL 'i:S=E F  
private String sFilePath; //Saved File's Path Esdv+f}4;  
private String sFileName; //Saved File's Name BD2Gv)?g  
private int nSplitter; //Count of Splited Downloading File )0o|u>  
T_j0*A$  
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public SiteInfoBean() ~Dbu;cqR@  
{//nSplitter的缺省值为5 RPw1i*  
//default value of nSplitter is 5 Lvb'qZ6n  
this("","","",5); RveEA/&&  
} AzMX~cd  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6m0-he~  
{ 9Xe|*bT
  
sSiteURL= sURL; af_bG;  
sFilePath = sPath; QfV:&b`  
sFileName = sName; %Vb~}sT:  
this.nSplitter = nSpiltter; E?h'OR@_ L  
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} b"(bT6XO!  
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public String getSSiteURL() GLA4O)  
{ ~p{ fl?  
return sSiteURL; Mk/ZEyq^  
} U]Fnf?(  
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public void setSSiteURL(String value) 0Wb3M"#9<  
{ YK V"bI  
sSiteURL = value; (m() r0:@  
} 2Uy}#n|)r  
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public String getSFilePath() u>.>hQ  
{ ~>uu1[/  
return sFilePath; i9^m;Y)^I  
} a/Cc.s   
7 V=%&+  
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public void setSFilePath(String value) K7},X01^  
{ ub-vtRpm  
sFilePath = value; *#Iqz9X.Y3  
} ug?#Oa  
:?$<:  
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public String getSFileName() SJO^.[  
{ 2 W Wr./q  
return sFileName;  )QB9zl:  
} oF.H?lG7`  
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public void setSFileName(String value)  L{u1_  
{ $+n5l@W  
sFileName = value; !}J19]\  
} R 5Cy%  
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public int getNSplitter() J1d|L|M  
{ &Ui&2EW  
return nSplitter; e ls&_BPE  
} yHxi^D]  
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public void setNSplitter(int nCount) JT*Pm"}  
{ ~!ICBF~j  
nSplitter = nCount; CW@G(R  
} &\Yd)#B/  
} 8Og)(BC  
7WN$ rl5/  
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/* .KxE>lJbqM  
**Utility.java sX#
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*/ % ^&D,  
package NetFox; N4wMAT:h  
&$.x1$%  
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public class Utility { n$jf(
$*  
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public Utility() ~f[91m!+  
{ 5h>t4 [~  
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} } bEu+bZ  
kA(q-Re$B*  
//线程睡眠 AK5$>Pkvk  
public static void sleep(int nSecond) mNApFwZ  
{ >Av%[G5=h#  
try{ g#<M/qn  
Thread.sleep(nSecond); dWhF[q"  
} Ujss?::`G  
catch(Exception e) ;AE%f.Y  
{ fa;GM7<e)  
e.printStackTrace (); <>K@#|%Y&  
} ^<nN~@
j  
} !d=Q@oy5  
qYR+qSAJP  
//日志 gb@ |\n  
public static void log(String sMsg) b}jLI_R{  
{ U-GV^j  
System.err.println(sMsg); oxL4* bqZ  
} e3{L%rQE  
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Abf=b<bu  
public static void log(int sMsg) a3oSSkT  
{ m&Lc."  
System.err.println(sMsg);  
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} rFR2c?j8  
} d 3
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od~`q4p1(-  
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/* 7Om)uUjU4  
**TestMethod.java P;
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*/ i*%2 e)  
package NetFox; }V %b  
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public class TestMethod { 9 ulr6  
fO{E65uA  
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public TestMethod() @X6|[r&Z  
{ ///xx/weblogic60b2_win.exe >SZ9,K4Gs  
try{ ^,KN@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); S+C^7# lT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); to*<W,I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); U[8Cg  
fileFetch.start(); ()+;KF8  
} 5-pz/%,  
catch(Exception e){e.printStackTrace ();} a4M`Bk;mb  
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} _;+N=/l0  
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public static void main(String[] args) c{t[iXDG  
{ ,/g\;#:{@]  
new TestMethod(); N:@C% UW}  
} W[3)B(Vq<E  
} kM\O2ay  
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