http断点续传简单实现（java)

/* tCH!m
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**SiteFileFetch.java Gx/Oi)&/  
*/ ~!d\^Z
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package NetFox; `Y$4 H,8L  
import java.io.*; GR_-9}jQP  
import java.net.*; (mpNcOY<D  
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public class SiteFileFetch extends Thread { x=P\qjSa  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 97*p+T<yp  
long[] nStartPos; //开始位置 &DX! f  
long[] nEndPos; //结束位置 ~TD0zAA&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <)H9V-5aZ  
long nFileLength; //文件长度 ~qKY) "gG  
boolean bFirst = true; //是否第一次取文件 'n3uu1C  
boolean bStop = false; //停止标志 %J?xRv!  
File tmpFile; //文件下载的临时信息 Ffz,J6b  
DataOutputStream output; //输出到文件的输出流 JX;G
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )Nw8O{\  
public SiteFileFetch(SiteInfoBean bean) throws IOException YK'<NE3 4  
{ n b?lTX~  
siteInfoBean = bean; .|70;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |0b`fOS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); i[3'ec3  
if(tmpFile.exists ()) kgP0x-Ap  
{ aB&&YlR=n<  
bFirst = false; f}P3O3Yv&  
read_nPos(); !*N@ZL&X  
} 4Z&lYLq;  
else G5 WVr$  
{ gR;i(81U  
nStartPos = new long[bean.getNSplitter()]; r`d4e,(  
nEndPos = new long[bean.getNSplitter()]; \~$#1D1f  
} :4/3q|cn  
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} f.$af4 u  
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public void run() *.t7G  
{ .W!i7  
//获得文件长度 ;?p>e
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//分割文件 m-#2n? z-  
//实例FileSplitterFetch VU3upy<  
//启动FileSplitterFetch线程 `Ggbi4),  
//等待子线程返回 +=</&Tm  
try{ hRhe& ,v  
if(bFirst) h*](a_0  
{  x'<X!gw  
nFileLength = getFileSize(); /y}xX  
if(nFileLength == -1) oap4rHk}  
{ q@8*
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System.err.println("File Length is not known!");
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} `X&gE,Ii  
else if(nFileLength == -2) A3/k@S-R2  
{ 2P0*NQ  
System.err.println("File is not access!"); eeB{c.#  
} ZUd
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else u'BaKWPS  
{ yY q,*<G  
for(int i=0;i<nStartPos.length;i++) [{,1=AB  
{ SO!8Di  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); o>pJPV  
} SwMc pNo  
for(int i=0;i<nEndPos.length-1;i++) |CRn c:  
{ *$g-:ILRuZ  
nEndPos = nStartPos[i+1]; vr=#3>  
} +CNv l  
nEndPos[nEndPos.length-1] = nFileLength; ( a#BV}=  
} wFZP,fQ9l  
} &tj!*k'  
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//启动子线程 _oeS Uzq.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G4"F+%.  
for(int i=0;i<nStartPos.length;i++) 5r^
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{ Cw&KVw*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G"A#Q"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nBYZ}L q  
nStartPos,nEndPos,i); 6Z"X}L,*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); uwGc@xOgg,  
fileSplitterFetch.start(); zdam^o  
} tKXIk9e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *s3/!K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7@W>E;go  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X"eYK/7  
nEndPos = " + nFileLength); {+>-7 9b  
// fileSplitterFetch[nPos.length-1].start(); r9?Mw06Wc5  
3=oDQ&UFt  
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//等待子线程结束 AA>P`C$&M  
//int count = 0; 2D5StCF$O  
//是否结束while循环 La[V$+Y  
boolean breakWhile = false; [Y`W  
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while(!bStop) 7b+6%fV  
{ ?}Y]|c^W  
write_nPos(); YN5rml'-  
Utility.sleep(500); pd$[8Rmj_  
breakWhile = true; a d\ot#V  
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for(int i=0;i<nStartPos.length;i++) ,PDQzJY  
{ MF'JeM;H  
if(!fileSplitterFetch.bDownOver) 8LCb+^  
{ kyV8K#}%8  
breakWhile = false; "#g}ve,  
break; E!F^H^~$8  
} &UFZS94@r  
} ~wdGd+ez  
if(breakWhile) cU  
break; {_*yGK48n  
)t%b838l%  
\Vk:93OH21  
//count++; Q+{n-? :  
//if(count>4) c &c@M$  
// siteStop(); |DwZ{(R"W  
} #w=~lq)9  
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System.err.println("文件下载结束！"); [nh>vqum  
} m]&SNz=  
catch(Exception e){e.printStackTrace ();} o2ECG`^b  
}
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//获得文件长度 s>c=c-SP.  
public long getFileSize() k}rbim  
{ }6ldjCT/,  
int nFileLength = -1; Vjpy~iP4B  
try{ n=q76W\  
URL url = new URL(siteInfoBean.getSSiteURL()); 7xR\kL.,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G#$-1"!`  
httpConnection.setRequestProperty("User-Agent","NetFox"); _yT Ed"$  
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int responseCode=httpConnection.getResponseCode();
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if(responseCode>=400) q,%st~  
{ 1Z&(6cDY8M  
processErrorCode(responseCode); TcoB,Kdce  
return -2; //-2 represent access is error glw+l'@  
} Ho]su?  
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String sHeader; W@esITr  
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for(int i=1;;i++) M3au{6y  
{ d_P` qA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); T> p&$]OG  
//Utility.log(in.readLine()); hqdDm  
sHeader=httpConnection.getHeaderFieldKey(i); 1 -b_~DF  
if(sHeader!=null) $pz/?>!  
{ [N'h%1]\  
if(sHeader.equals("Content-Length")) R@2X3s:  
{ 1E$|~   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); wgA_38To  
break; y)<q/  
} 2A!FDr~cdT  
} [-x7_=E#  
else 5IG-~jzCLb  
break; (V@HR9?W)  
} 4&iCht =  
} Z30A{6}  
catch(IOException e){e.printStackTrace ();} "wc<B4"  
catch(Exception e){e.printStackTrace ();} tl>7^hH  
7-A2_!_x{  
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Utility.log(nFileLength); i-&yH  
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return nFileLength; q cno^8R  
} LH6vLuf  
}PpUAt~g  
_ x*3PE  
//保存下载信息（文件指针位置） >R=|Wo`Ri  
private void write_nPos() wKHBAW[i]  
{ fXB0j;A  
try{ `F6C-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); p b,. r  
output.writeInt(nStartPos.length); :v 4]D4\o  
for(int i=0;i<nStartPos.length;i++) IRbfNq^:  
{ WF"k[2  
// output.writeLong(nPos); DV{=n C  
output.writeLong(fileSplitterFetch.nStartPos); ?X;RLpEc|A  
output.writeLong(fileSplitterFetch.nEndPos); [00m/fT6  
} $od7;%  
output.close(); %XTI-B/K  
} x)VJFuqy  
catch(IOException e){e.printStackTrace ();} =\d?'dII:  
catch(Exception e){e.printStackTrace ();} Xm&L BX  
} \`"ht  
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//读取保存的下载信息（文件指针位置） {>;R?TG]$  
private void read_nPos() 1 {)Q[#l  
{ 92-I~ !d  
try{ rLT!To  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?%kV?eu'  
int nCount = input.readInt(); |7Kbpj  
nStartPos = new long[nCount]; S[QrS7  
nEndPos = new long[nCount]; I2DpRMy  
for(int i=0;i<nStartPos.length;i++) J8~ha
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{ 9>$p  
nStartPos = input.readLong(); $ulOp;~A%  
nEndPos = input.readLong(); L=h'Qgk%  
} -^wl>}#*T3  
input.close(); :H[6Lg\*  
} Aa]"  
catch(IOException e){e.printStackTrace ();} -.3w^D"l  
catch(Exception e){e.printStackTrace ();} "ITIhnE  
} P>6{&(  
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private void processErrorCode(int nErrorCode) RT5T1K08I  
{ !%>7Dw(kt  
System.err.println("Error Code : " + nErrorCode); bN88ua}k{  
} iR0y"Cii  
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]{LjRSV
 
//停止文件下载 +^<](z  
public void siteStop() BluVmM3Vj  
{ |D
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bStop = true; c:g'.'/*  
for(int i=0;i<nStartPos.length;i++) 8i,K~Bu=  
fileSplitterFetch.splitterStop(); kNL\m[W8$  
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} Xx(T">
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} 3BLq
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//负责部分文件的抓取 M@ZI\  
**FileSplitterFetch.java KG5>]_GH  
*/ ]
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package NetFox; lHIM}~#;nd  
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import java.io.*; :j`sr  
import java.net.*; ~v"L!=~G;a  
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public class FileSplitterFetch extends Thread { -`t^7pr  
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i 3SHg\~Z  
String sURL; //File URL 2:=  
long nStartPos; //File Snippet Start Position ,v&(YOd  
long nEndPos; //File Snippet End Position 4Z,!zFS$`  
int nThreadID; //Thread's ID _-Fs#f8  
boolean bDownOver = false; //Downing is over o8vug$=Z  
boolean bStop = false; //Stop identical x3krbUlx  
FileAccessI fileAccessI = null; //File Access interface 4H<lm*!^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException a@*\o+Su  
{ Qw)c$93  
this.sURL = sURL; \^%}M!tan  
this.nStartPos = nStart; <d_!mKw  
this.nEndPos = nEnd; @OHm#`~  
nThreadID = id; $tS}LN_!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }iuw5dik+  
} I!?}jo3  
2 Vrw  
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public void run() IaXeRq?<  
{ ofv)SCjd  
while(nStartPos < nEndPos && !bStop) tnG# IU *  
{ pHJ
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try{ l/awS!Q/nF  
URL url = new URL(sURL); O8.5}>gDn.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "w.3Q96r  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3%ZOKb"D*  
String sProperty = "bytes="+nStartPos+"-"; jalg5`PU0  
httpConnection.setRequestProperty("RANGE",sProperty); VU d\QR-  
Utility.log(sProperty); Wiu"k%Qsh  
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InputStream input = httpConnection.getInputStream(); Ez=Olbk  
//logResponseHead(httpConnection); J9[r
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byte[] b = new byte[1024]; Nu7 !8[?r*  
int nRead; ox (%5c)b|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /~f'}]W  
{ HoL Et8Q  
nStartPos += fileAccessI.write(b,0,nRead); /Mu@,)''  
//if(nThreadID == 1) qm o9G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #?9;uy<j.q  
}  !=P1%  
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Utility.log("Thread " + nThreadID + " is over!"); fx>4  
bDownOver = true; p"ZG%Ow5Q]  
//nPos = fileAccessI.write (b,0,nRead); w=J3=T@TD  
} :A'y+MnK<  
catch(Exception e){e.printStackTrace ();} ';=O 0)u  
} '(L7;+E  
} e;}7G  
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//打印回应的头信息 R[x_j  
public void logResponseHead(HttpURLConnection con) 4Ic*9t3  
{ ~1vDV>dpE  
for(int i=1;;i++) C&rkvM8  
{  O+Y6N  
String header=con.getHeaderFieldKey(i); EA]U50L(  
if(header!=null) 1Z~FCJz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d,n 'n  
Utility.log(header+" : "+con.getHeaderField(header)); [e}]}t8m  
else (c &mCJN  
break; >e[i5  
} (jl D+Y_  
} 6MMOf\   
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public void splitterStop() Hn+~5@.  
{ !NvI:C_4|  
bStop = true; l3I:Q^x@  
} r:ptQo`1-  
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} 2)HuZda  
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/* Ks`J([(W&  
**FileAccess.java S2G
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*//文件访问(定位，写) xBi' X  
package NetFox; .MoU1n{Yc  
import java.io.*; ")XHak.JX  
~;{;,8!)  
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public class FileAccessI implements Serializable{ Doyx[zZ  
qm8B8&-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Cl8Cg~2  
RandomAccessFile oSavedFile; fN^8{w/O  
long nPos; P%&0]FCx  
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public FileAccessI() throws IOException Jgd'1'FOs  
{ e_ANUll1  
this("",0); 8_B4?` k  
} ;dZZ;#k%  
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public FileAccessI(String sName,long nPos) throws IOException !1H# 6  
{ 9BBmw(M}  
oSavedFile = new RandomAccessFile(sName,"rw"); kr
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this.nPos = nPos; a:IC)]j$_  
oSavedFile.seek(nPos); EF}\brD1  
} nIy}#MUd|q  
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public synchronized int write(byte[] b,int nStart,int nLen) 'RYIW/a  
{ `
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int n = -1; F]]]y5t  
try{ /,&<6c-Q@W  
oSavedFile.write(b,nStart,nLen); =O_4|7Zl  
n = nLen; `l){!rg8IC  
} KD7dye  
catch(IOException e) Tg)|or/%  
{ O6a<`]F  
e.printStackTrace (); wX5tp1 ?1J  
} ipgC RHE  
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return n; Tc &z:  
} (U_ujPD ?  
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} 1&evG-#<:  
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/* KNpl:g3{<Q  
**SiteInfoBean.java u4F5h PO]  
*/ lC("y' ::  
package NetFox; cr?Q[8%t1  
"
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public class SiteInfoBean { ~f1%8z  
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private String sSiteURL; //Site's URL #Z`q+@@]A  
private String sFilePath; //Saved File's Path 8\ +T8(m  
private String sFileName; //Saved File's Name G"U9E5O  
private int nSplitter; //Count of Splited Downloading File 7>Ouqxh21  
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kmsb hYM)  
public SiteInfoBean() I{9QeRI  
{//nSplitter的缺省值为5 >WQMqQ^t@  
//default value of nSplitter is 5 Mxsa-?R;v  
this("","","",5); k,E{C{^M  
} EZy)A$|  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ceh j;  
{ "9P>a=Y  
sSiteURL= sURL; \y)rt )  
sFilePath = sPath; { MSkHf=  
sFileName = sName; B^Nf #XN(  
this.nSplitter = nSpiltter; ;R5`"`  
%C'?@,7C  
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} fk[-mZ  
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public String getSSiteURL() YEs&  
{ 7>|J8*/Nd  
return sSiteURL; ,o{9$H5{  
} *:YiimOY"  
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KRLQ #,9  
public void setSSiteURL(String value) WJndoB.f[2  
{ udF~5w H  
sSiteURL = value; 5k3n\sqZA  
} <fjX[l<Uz  
{3p4:*}  
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public String getSFilePath() 7 60Y$/Wz  
{ ?m=N]!n  
return sFilePath; #*uL)2nR  
} +p_CN*10H  
pb?c$n$u*  
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public void setSFilePath(String value) NP#w+Qw  
{ /k6MzFoid  
sFilePath = value; *{@Nq=fE  
} c9'vDTE%~  
 &)Tdc  
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public String getSFileName() GT!M[*[  
{ wj<6kG  
return sFileName; /y#f3r+*2  
} =Z3F1Cq?  
fue(UMF~  
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public void setSFileName(String value) }6}l7x  
{ E7Ul;d  
sFileName = value; 3cyHfpx-W  
} p8H'{f\G  
.fFCC`&T  
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public int getNSplitter() ZW8vza  
{ y8Z_Itlf  
return nSplitter; }wjw:M  
} "3"V3w  
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public void setNSplitter(int nCount) gA+qC7=p$  
{ &yTqZ*Yuk  
nSplitter = nCount; +z\^t_"f  
} 9y8&9<#  
} 3{^9]7UC  
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/-qNh>v4  
/* :&rt)/I  
**Utility.java k&q;JyUi  
*/ <QAFL uey  
package NetFox; V-2(?auZd  
|t&>5HM  
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public class Utility { ~'H]jN  
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public Utility() f#"J]p  
{ GL0L!="!  
bMu+TgAT,  
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} @#>rYAb8,  
SC!RbW@3  
//线程睡眠 FP`b>E qOH  
public static void sleep(int nSecond) 4JXeV&5Qk'  
{ 7~%?
#  
try{ q[ZTHd.-  
Thread.sleep(nSecond); =tn)}Y.<e  
} 6qpJUkd  
catch(Exception e) 9C9oUtS  
{ ,vawzq[oSy  
e.printStackTrace (); 0[# 3;a  
} a=1@*ID  
} NC`aP0S  
nFe<w  
//日志 q=m'^ ,gPS  
public static void log(String sMsg) oj<gD  
{ $am$EU?s  
System.err.println(sMsg); t!X.|`h  
} @6sqMw}  
|\t-g"~sN  
7~p@0)''  
public static void log(int sMsg) b<ZIWfs  
{ PO^ij2eS  
System.err.println(sMsg); '<xXK@=KEI  
} "ycJ:Xv49  
} P%VSAh\|n  
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fk>aqm7D!  
/* IGQFtO/x  
**TestMethod.java ) 7@ `ut  
*/ F4z{LhZ  
package NetFox; \fdv]f  
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[Ek7b*  
public class TestMethod { (@VMH !3  
70nqD>M4  
GPudaF{  
public TestMethod() ]Sz:|%JP1  
{ ///xx/weblogic60b2_win.exe e}7lBLK]*  
try{ n\'4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); yYYSeH  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^*Q ?]N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7"x;~X  
fileFetch.start(); S Lj!v&'  
} $6 9&O  
catch(Exception e){e.printStackTrace ();} Y('#jU  
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h"Q8b}$^)  
} b3[!V{|  
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public static void main(String[] args) ]|ag  
{ ,PW'#U:  
new TestMethod(); i)#dWFDTv  
} P>D)7V9Hh  
} Pn1^NUMZJ  
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