http断点续传简单实现（java)

/* MA .;=T  
**SiteFileFetch.java \,R;  
*/ #XQ/y}(  
package NetFox; gL<n?FG4b  
import java.io.*; qu B[S)2}  
import java.net.*; 5 -i,Tx&:  
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public class SiteFileFetch extends Thread { _8G w Mj  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^\}MG!l  
long[] nStartPos; //开始位置 |E+.y&0;  
long[] nEndPos; //结束位置 ZRMim6a4X  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vQrxx  
long nFileLength; //文件长度 FJ_JaIby  
boolean bFirst = true; //是否第一次取文件 B=A!hXNa  
boolean bStop = false; //停止标志 St5;X&Q  
File tmpFile; //文件下载的临时信息 wFMH\a  
DataOutputStream output; //输出到文件的输出流 ERPg TZT  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） APu$t$dmm  
public SiteFileFetch(SiteInfoBean bean) throws IOException -YNpHd/;,  
{ i(~DhXz*T  
siteInfoBean = bean; #j2kT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k>&cHCS`*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =.`\V]
 
if(tmpFile.exists ()) o z*;q]  
{ RV~t%Sw^  
bFirst = false; m6R/,  
read_nPos(); =3-=p&*  
} E/cV59  
else ^E}?YgNp  
{ h,/Aq  
nStartPos = new long[bean.getNSplitter()]; ?:r?K|Ku  
nEndPos = new long[bean.getNSplitter()]; =lAjQt
 
} IfmQPs+f  
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} BX/3{5Y>{  
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public void run() E#
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{ 2^[dy>[y0  
//获得文件长度 V$ZclV2:Ih  
//分割文件 @c^ Dl  
//实例FileSplitterFetch l"ms:v  
//启动FileSplitterFetch线程 fd[N]I3  
//等待子线程返回 `W86]ut[  
try{ 1(p:dqGS  
if(bFirst) ///Lg{ie  
{ !.P||$x`&  
nFileLength = getFileSize(); A}ZZQ  
if(nFileLength == -1) xn*$Ty+  
{ <,CrE5Pl  
System.err.println("File Length is not known!"); W>#yXg9  
} iC3z5_g*@  
else if(nFileLength == -2) TuQGF$n@  
{ #@FA=p[%  
System.err.println("File is not access!"); ?tYZ/  
} ZiUb+;
JA  
else 0&s6PS%  
{ sD3ZZcy|=  
for(int i=0;i<nStartPos.length;i++) 1(DiV#epG  
{  GK/Po51  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ZVgfrvZP  
} jn^X{R\  
for(int i=0;i<nEndPos.length-1;i++) d?7?tL2  
{ @v2<T1UC  
nEndPos = nStartPos[i+1]; s|p I`  
} gsL=_# ?  
nEndPos[nEndPos.length-1] = nFileLength; 2 GR
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} nJe}U#  
} -leX|U}k  
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//启动子线程 4]r_K2.cc  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *I 1H  
for(int i=0;i<nStartPos.length;i++) >[ B.y  
{ wqo:gW_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wsmgkg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), aDdxR:  
nStartPos,nEndPos,i); &Ym):pc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WJq>%<#  
fileSplitterFetch.start(); t^'nh 1=  
} 2u$-(JfoS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "'CvB0>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); IHTimT?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a/ Ac^!(  
nEndPos = " + nFileLength); Dck/Ea  
// fileSplitterFetch[nPos.length-1].start(); z_>~=Mm  

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YF{MXK}  
//等待子线程结束 "L2*RX.R  
//int count = 0; `4*I1WZW  
//是否结束while循环 S1$^ _S =  
boolean breakWhile = false; ?("O.<
 
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while(!bStop) [S'1OR$FQ\  
{ ehW[LRtq  
write_nPos(); J2qsZ  
Utility.sleep(500); &>qUT]w  
breakWhile = true; SRfh{u  
kQ>2W5o-d-  
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for(int i=0;i<nStartPos.length;i++) `ArUoYbB  
{ yx8G9SO?  
if(!fileSplitterFetch.bDownOver) Lip#uuuXXN  
{ Rs=Fcvl  
breakWhile = false; UC+Qn  
break; I<2`wL=  
} nZioFE}  
} O::FB.k  
if(breakWhile) 44e]sT.B  
break; <.)=CK  
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//count++;
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//if(count>4) THwM',6  
// siteStop(); N[ =I  
} [h-6;.e  
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|V5BL<4  
System.err.println("文件下载结束！"); +c_AAMe  
} )>ML7y  
catch(Exception e){e.printStackTrace ();} FJ84'T\~  
} 3X(^`lAf)  
:Ak^M~6a5  
:Pq&l.  
//获得文件长度 c^=q(V  
public long getFileSize() 8 o}5QOW  
{ k1D7=&i  
int nFileLength = -1; bZ_&AfcB  
try{ vGyQ306  
URL url = new URL(siteInfoBean.getSSiteURL()); 4>(K~v5;N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a >fA-@  
httpConnection.setRequestProperty("User-Agent","NetFox"); .45wwouZkc  
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c&T5C,]  
int responseCode=httpConnection.getResponseCode(); MNs<yQ9I'  
if(responseCode>=400) ai;!Q%B#Q  
{ l]|&j`'O  
processErrorCode(responseCode); bpsyO>lx/  
return -2; //-2 represent access is error G5qsnTxUJ  
} Lx-%y
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String sHeader; .g/!u(iy  
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m LajiZ Bf  
for(int i=1;;i++) o2(w  
{ AkW,Fp1e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ANPG3^w  
//Utility.log(in.readLine()); :G#%+,  
sHeader=httpConnection.getHeaderFieldKey(i);
Y#lAG@$  
if(sHeader!=null) X)SUFhP\  
{ eQQVfEvS  
if(sHeader.equals("Content-Length")) 8GxT!  
{ Oi?Q^ISxP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3R/6/+S-  
break; ~^.,Ftkb@7  
} {Q/@Y.~<  
} 08
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else yHM29fEZk  
break; x/1FQ>n:9  
} cMi9 Z]  
} 5 n4/}s  
catch(IOException e){e.printStackTrace ();} 07^.Z[(pCt  
catch(Exception e){e.printStackTrace ();} M(8xwo-W  
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Utility.log(nFileLength); ruqE]Hx9(  
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return nFileLength; lU|ltnU  
} 6Hc25NuQZ  
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aJm5`az)  
//保存下载信息（文件指针位置） RGV{KL  
private void write_nPos() N+SA$wG  
{ [9?
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try{ iP7KM*ks  
output = new DataOutputStream(new FileOutputStream(tmpFile)); PvUY Q>Kw  
output.writeInt(nStartPos.length); Bptt"  
for(int i=0;i<nStartPos.length;i++) Ypm*or  
{ b<fN,U<k  
// output.writeLong(nPos); 9F,XjPK
=  
output.writeLong(fileSplitterFetch.nStartPos); yMNOjs'c {  
output.writeLong(fileSplitterFetch.nEndPos); j+<!4 0#  
} 1slt[&4N  
output.close(); Y\!:/h]E&  
} m$Tt y[0  
catch(IOException e){e.printStackTrace ();} /XRgsF  
catch(Exception e){e.printStackTrace ();} ^umHuAAE  
} Ahd{f!  
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//读取保存的下载信息（文件指针位置） &m(eMX0lU  
private void read_nPos() 5NSXSR9c  
{ ziW[qH {  
try{ 2b {Y1*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); EI9Yv>7d{  
int nCount = input.readInt(); yyR@kOGga  
nStartPos = new long[nCount]; uJ*|SSN~  
nEndPos = new long[nCount]; r'}#usB(  
for(int i=0;i<nStartPos.length;i++) bv[*jr;45  
{ _}Gs9sHr0K  
nStartPos = input.readLong(); RAyR&p  
nEndPos = input.readLong(); 7Ph+Vs+h  
} `Geq,  
input.close(); d\z':d.Tt  
} 43J8PMY  
catch(IOException e){e.printStackTrace ();} {iq{<;)U?U  
catch(Exception e){e.printStackTrace ();} p|Fhh\,*`X  
} G`!;RX  
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8DrKq]&  
private void processErrorCode(int nErrorCode) (aCl*vV1  
{ J! eVw\6  
System.err.println("Error Code : " + nErrorCode); nfvs"B;  
} I^A01\p  
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FHH2  
//停止文件下载 = &aD!nTx  
public void siteStop() .+AO3~Dg  
{ ldoN!J  
bStop = true; ~w%Z Bp  
for(int i=0;i<nStartPos.length;i++) =TI|uD6T  
fileSplitterFetch.splitterStop(); eWx6$_|  
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} o9HDxS$~^  
} Ll
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//负责部分文件的抓取 7]9s_13]  
**FileSplitterFetch.java -ap;Ul?  
*/ e;}5~dSi  
package NetFox; >Q\H1|?  
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import java.io.*; Zr2QeLQC(  
import java.net.*; FkECY  
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public class FileSplitterFetch extends Thread { 4_I,wG@  
)@`w^\E_~_  
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String sURL; //File URL _5YL !v&  
long nStartPos; //File Snippet Start Position lB\j>.c  
long nEndPos; //File Snippet End Position $l[*Y  
int nThreadID; //Thread's ID LveqG  
boolean bDownOver = false; //Downing is over +Vf|YLbhJ  
boolean bStop = false; //Stop identical S(-=I!.G{  
FileAccessI fileAccessI = null; //File Access interface iii$)4V  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c!\y\r  
{ $BBfsaJPT  
this.sURL = sURL; /s*
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this.nStartPos = nStart; .y2<2eW  
this.nEndPos = nEnd; x}>tX
  
nThreadID = id; u!`C:C'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]R>k0X.V  
} b~1p.J4  
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!<6wrOMaO  
public void run() +m7x>ie)  
{ 6$dm-BI  
while(nStartPos < nEndPos && !bStop) $-AvH(@  
{ >`\*
{]  
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try{ g4$%)0x%  
URL url = new URL(sURL); Zz&i0r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &s;%(c04A  
httpConnection.setRequestProperty("User-Agent","NetFox"); pn7 :")Zx  
String sProperty = "bytes="+nStartPos+"-"; A>
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httpConnection.setRequestProperty("RANGE",sProperty); |uZ=S]V@  
Utility.log(sProperty); tr/dd&(Y1  
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InputStream input = httpConnection.getInputStream(); 7VXeu+-P  
//logResponseHead(httpConnection); 835Upj>  
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byte[] b = new byte[1024]; R39R$\  
int nRead; 5)oIPHXw  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B:r-')!0$#  
{ g^4FzJ  
nStartPos += fileAccessI.write(b,0,nRead); 
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//if(nThreadID == 1) .}<B*e
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9iy|=  
} @ :4Kk 4g1  
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.-Lqo=o\  
Utility.log("Thread " + nThreadID + " is over!"); n1/lE)  
bDownOver = true; Wkk Nyg,  
//nPos = fileAccessI.write (b,0,nRead); 1;gSf.naG  
} 2!otVz!Mh  
catch(Exception e){e.printStackTrace ();} ,< icW&a  
} uW
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} QPcB_wUqu  
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//打印回应的头信息 '> Q$5R1  
public void logResponseHead(HttpURLConnection con) U ^9oc&  
{ .>'Z9.Xnk  
for(int i=1;;i++) 9h(hx7]  
{ ?BZ][~n-Q  
String header=con.getHeaderFieldKey(i); %Nn'p"  
if(header!=null) !m|%4/ M@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); LI<5;oE;  
Utility.log(header+" : "+con.getHeaderField(header)); w;$+7  
else qU n>  
break; ui{_w @o  
} {LD8ie|x1`  
} KTEis!w  
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public void splitterStop() tp^'W7E  
{ _D4}
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bStop = true; S%fBt?-Cm  
} 7dJaWD:&   
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} ):@%xoF5  
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/* ,AM-cwwT:u  
**FileAccess.java eFI4(Y  
*//文件访问(定位，写) \(FDR  
package NetFox; _64@zdL+  
import java.io.*; -JENY|6  
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public class FileAccessI implements Serializable{ *~uuCLv_  
{ bn#:75r  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !?*!"S-Sl  
RandomAccessFile oSavedFile; 3@?YTez#  
long nPos; $@kw>2  
F8Wq&X#r  
1[`<JCFClc  
public FileAccessI() throws IOException c7IR06E  
{ |u;PU`
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this("",0); %Ab_PAw  
} se HbwO3 b  
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public FileAccessI(String sName,long nPos) throws IOException yo,!u\^x  
{ & }}WP:U  
oSavedFile = new RandomAccessFile(sName,"rw"); lh_zZ!)g  
this.nPos = nPos; ?\M6P?tpo&  
oSavedFile.seek(nPos); zpqNmxmF  
} # :w2Hf6Q  
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x+  
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public synchronized int write(byte[] b,int nStart,int nLen) 9nS!  
{ %:?QE ;  
int n = -1; )6 <byO  
try{ a&"*UJk<?  
oSavedFile.write(b,nStart,nLen); _l=  
n = nLen; ](:FW '-  
} S)@vl^3ec  
catch(IOException e) S{T d/1}  
{ /t)c fFM  
e.printStackTrace (); DF|s,J`98  
} zn1Rou]6  
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return n; =e8L7_;  
} M.N~fSJ  
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} SuH.lCF-g  
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/* v#]v,C-*  
**SiteInfoBean.java i6#]$B  
*/ D>b5Uwt  
package NetFox; 56SS >b  
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public class SiteInfoBean { +VLe'|  
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@U3foL2\  
private String sSiteURL; //Site's URL ,o@~OTja*  
private String sFilePath; //Saved File's Path =ch Af=  
private String sFileName; //Saved File's Name m_!vIUOz  
private int nSplitter; //Count of Splited Downloading File yC 7Vb P  
3E!<p  
vo6[2.HS  
public SiteInfoBean() g2{H^YUN$_  
{//nSplitter的缺省值为5 (21 W6  
//default value of nSplitter is 5 YP#AB]2\}  
this("","","",5); u2-@?yt  
} Ly)(_Tp@+  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gJ3OK!/  
{ _h1 HuL  
sSiteURL= sURL; J(EaE2  
sFilePath = sPath; ewAH'H]o  
sFileName = sName; /}nrF4S  
this.nSplitter = nSpiltter; uqa4&2(I=j  
fEj9R@u+h  
,zN3? /7  
} X$-boe?  
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NDRW  
public String getSSiteURL() v;fJM5PA  
{ ,ykPQzO  
return sSiteURL; &R'w-0k_  
}
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% QPWw~}:  
public void setSSiteURL(String value) DIG0:)4R.  
{ dU ,)TKQ  
sSiteURL = value; ha|@ Xp  
} kRN|TDx(  
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public String getSFilePath() TsaW5ho<p  
{ 7_Ba3+9jpa  
return sFilePath; 1 [Sv  
} *.m{jgi1X  
L
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\}$*}gW[}  
public void setSFilePath(String value) 8%o~4u3  
{ jDlA<1  
sFilePath = value; x7
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} /[a|DUoHO  
bKk CW  
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public String getSFileName() j|VXC(6P,  
{ !uWxRpT,7  
return sFileName; Md8(`@`o  
} ^Sy^+=wK3  
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2X|CuL{]  
public void setSFileName(String value) 2?GXkPF2;A  
{ a(8>n Z,V  
sFileName = value; <1aa~duT  
} R{*_1cyW  
9;=q=O/  
Ur^YG4(  
public int getNSplitter() C/F@ ]_y  
{ L)q`D2|'  
return nSplitter; 6#<Ir @z  
} c}\ 'x5:o  
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6 -]>]Hr-  
public void setNSplitter(int nCount) QT#b>xV)1  
{ y0,Ft/D  
nSplitter = nCount; x.I][(}  
} kr^0% A  
} G9\EZ\x!  
'.pgXsC:=?  
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/* Ay2b,q  
**Utility.java uu}'i\Q  
*/ 8{oZi]ob  
package NetFox; F4Rr26M  
);=Q] >  
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public class Utility { 9*' &5F=  
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public Utility() $nj\\,(g  
{ V]Sgx00;  
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]*0(-@  
} 19
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_0K.Fk*(!  
//线程睡眠 f6Ml[!aU  
public static void sleep(int nSecond) (}G!np  
{ Ddb-@YD&+0  
try{ ?fV?|ZGZ
I  
Thread.sleep(nSecond); {o( * f  
} F"I*-!o  
catch(Exception e) y>`5Kyj3-@  
{
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e.printStackTrace (); E-^2"j>o  
} 2SYKe$e  
} EOhC6>ATh  
[O\9 9>  
//日志 "9w}dQ  
public static void log(String sMsg) &I%IaNco  
{ avg4K*
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System.err.println(sMsg); ^
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} `g--QR  
\6{LR&  
+s ULo  
public static void log(int sMsg) #G[t X6gU  
{ ^+wk  
System.err.println(sMsg); "TfI+QgLF  
} <KX&zi<L)  
} i0\)%H:z
 
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/* e gI&epN  
**TestMethod.java 19p8B&  
*/ uxb:^d?D!  
package NetFox; :5jexz."M  
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public class TestMethod { 9
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X &D{5~qC  
NEw$q4  
public TestMethod() ~cI
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{ ///xx/weblogic60b2_win.exe "kU
]  
try{ BKay*!'PX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~ltg  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); gX^ PSsp  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %&h c"7/k  
fileFetch.start(); q6REh;$  
} Z5$fE7ba+  
catch(Exception e){e.printStackTrace ();} zW5C1:.3K  
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tb,9a!?  
} P#MK  
6Hk="$6K  
~>g+2]Bn>$  
public static void main(String[] args) 7\X$7  
{ {~_Y _-  
new TestMethod(); Bd&`Xfebj  
} VO_dA4C}z  
} FqZgdmwR  
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