http断点续传简单实现（java)

/* ioE66-n  
**SiteFileFetch.java [W^6u7~  
*/ Wl^prs7}c  
package NetFox; u=p ;A1oy  
import java.io.*; vjexx_fq  
import java.net.*; hQgk.$g  
2ApDpH`fiJ  
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public class SiteFileFetch extends Thread { [;>zqNy  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ,!o\),N  
long[] nStartPos; //开始位置 viW~'}^k7  
long[] nEndPos; //结束位置 ikEWY_1Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _&k'j)rg  
long nFileLength; //文件长度 1g~Dm}m  
boolean bFirst = true; //是否第一次取文件 p9FA_(`^  
boolean bStop = false; //停止标志 oso1uAOfp  
File tmpFile; //文件下载的临时信息 N0y;PVAGu  
DataOutputStream output; //输出到文件的输出流 J~_L4*Jw  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kPx]u\  
public SiteFileFetch(SiteInfoBean bean) throws IOException EIq{C-(  
{ w0a+8gexi  
siteInfoBean = bean; Bi9 N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |'V<>v.v  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2ru*#Z#(  
if(tmpFile.exists ()) ql#{=oGDnA  
{ ]Ks]B2Osz  
bFirst = false; TTA{#[=7  
read_nPos(); EmtDrx4!(f  
} "4Vi=*2V  
else Bo](n*i  
{ SeRK7Q&_  
nStartPos = new long[bean.getNSplitter()]; &y#\1K  
nEndPos = new long[bean.getNSplitter()]; D-TNFYYy2  
} )1ZJ  

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} O+(. 29  
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public void run() ZXssvjWQV}  
{ ])Q9=?Sd}  
//获得文件长度 dUsJv  
//分割文件 N27K  
//实例FileSplitterFetch 2-"Lxe65f  
//启动FileSplitterFetch线程 7.lK$J:  
//等待子线程返回 |?;"B:0  
try{ c"f-$^<  
if(bFirst) K%[}[.cW  
{ K^]?@oHO  
nFileLength = getFileSize(); uJ|5Ve  
if(nFileLength == -1) 75hFyh;u  
{ W G3mQ\k  
System.err.println("File Length is not known!"); xoz*UA
.  
} X*0eN3o.  
else if(nFileLength == -2) *'s2 K  
{ @,yFY  
System.err.println("File is not access!"); Gg}LC+Y  
} +s+PnZ%0V  
else JhMrm%  
{ ;i-D~Np|  
for(int i=0;i<nStartPos.length;i++) X_0{*!v8  
{ HonAK  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Gpxb_}P  
} ~u?x{[  
for(int i=0;i<nEndPos.length-1;i++) }Yo15BN+  
{ hIzPy3  
nEndPos = nStartPos[i+1]; $dVgFot  
} >PTu*6Z  
nEndPos[nEndPos.length-1] = nFileLength; iP#A
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} -Iruua7b  
} xyz\;
3  
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//启动子线程 $:-= >  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0-t4+T  
for(int i=0;i<nStartPos.length;i++) m|#(gX|F  
{ QX.F1T2e?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WrK^>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), yNWbI0a  
nStartPos,nEndPos,i); 0o"<^] _|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R^u^y{ohr  
fileSplitterFetch.start(); 93Ci$#<y  
} @|\s$L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6Ymo%OT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m|Q&Lphb8  
nEndPos = " + nFileLength); *{;A\sL  
// fileSplitterFetch[nPos.length-1].start(); 2)I'5
?I  
k+m_L{#m5  
,rl <ye*&  
//等待子线程结束 0R%uVJG  
//int count = 0; Z#cU#)`y1  
//是否结束while循环 8w@W8(3B  
boolean breakWhile = false; yS.fe[  
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while(!bStop) .+JPtL  
{ KJvJUq  
write_nPos(); k~9Ywf  
Utility.sleep(500); PEQvEruZ}  
breakWhile = true; 7i|hlk;  
&<#BsFz  
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for(int i=0;i<nStartPos.length;i++) CyBM4q
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{ b8b PK<  
if(!fileSplitterFetch.bDownOver) Kp=3\)&  
{ Mb/
6>  
breakWhile = false; $b 71  
break;  ?Ge*~d  
} |Nd.'|g,  
} @okm@6J*X  
if(breakWhile) m{yNnJ3O  
break; Mp@(/  
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3<'Q`H>  
//count++; #y9K-}u  
//if(count>4) yNMwd.r[  
// siteStop(); [,A'  
} {j=hQL3  
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System.err.println("文件下载结束！"); NwuBe:"@  
} ORPl^n-  
catch(Exception e){e.printStackTrace ();} ~i&< !O&  
} E#V-F-@2  
PH4bM  
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//获得文件长度 X1z0'gvh  
public long getFileSize() ps;o[gB@5  
{ iU+,Jeu  
int nFileLength = -1; %
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try{ G.E~&{5xQ  
URL url = new URL(siteInfoBean.getSSiteURL()); OuIW|gIu0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S@2Jj>3D?  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2+Y`pz47W  
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int responseCode=httpConnection.getResponseCode(); exN#!&;  
if(responseCode>=400) p~;z"Z  
{ n[S*gX0  
processErrorCode(responseCode); aeLo;!Jh  
return -2; //-2 represent access is error >;U%~yy}qc  
} v&,VC~RN-J  
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String sHeader; 3A/MFQ#2  
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for(int i=1;;i++) ,r,;2,;6nd  
{ Fm~}A4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >h-6B=  
//Utility.log(in.readLine()); 5*'N Q010  
sHeader=httpConnection.getHeaderFieldKey(i); Vk=<,<BB  
if(sHeader!=null) m`0{j1K  
{ 0~5}F^8[L  
if(sHeader.equals("Content-Length")) 7uH{UpslJ  
{ @!HMd{r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); j`M<M[C*4N  
break; z9c=e46O  
} J3E:r_+  
} BrmFwXLP"  
else -+Ji~;b  
break; Z+Zh;Ms  
} j-E>*N}-_  
} 9e*poG  
catch(IOException e){e.printStackTrace ();} WoR**J?}w  
catch(Exception e){e.printStackTrace ();} jl29~^@}1i  
4B>|Wft{p]  
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Utility.log(nFileLength); Rzj!~`&N  
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return nFileLength; JH,bSb  
} {D
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//保存下载信息（文件指针位置） 7-B'G/PS/  
private void write_nPos() v)pWx0l=  
{ f}d@G/L  
try{ [$+61n}.12  
output = new DataOutputStream(new FileOutputStream(tmpFile)); g-uFss  
output.writeInt(nStartPos.length); ]&BFV%kw  
for(int i=0;i<nStartPos.length;i++) f 8U;T$)  
{ Kwau:_B  
// output.writeLong(nPos); 0M.[) @  
output.writeLong(fileSplitterFetch.nStartPos); GoXHVUyp  
output.writeLong(fileSplitterFetch.nEndPos); 7:<>#  
} {(Z1Jo
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output.close(); =~*u(0sJa  
} qA[}\8}
h  
catch(IOException e){e.printStackTrace ();} w-/Tb~#E  
catch(Exception e){e.printStackTrace ();} k{8N@&D  
} y['icGU6  
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//读取保存的下载信息（文件指针位置） _"TG:RP  
private void read_nPos() :v48y.Ij7s  
{ u^9,u/gj  
try{ O;tn5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {)xrg s
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int nCount = input.readInt(); / nR
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nStartPos = new long[nCount]; ,+{ 43;a  
nEndPos = new long[nCount]; :oQaN[3>_  
for(int i=0;i<nStartPos.length;i++) AO]e^Q  
{ Su^Z{ Ud`  
nStartPos = input.readLong(); C
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nEndPos = input.readLong(); D':A-E
  
} 3+'w%I  
input.close(); U)6
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} W3kilhZ  
catch(IOException e){e.printStackTrace ();} H2p;J#cv@  
catch(Exception e){e.printStackTrace ();} m-]"I8[  
} a!.8^:B&  
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private void processErrorCode(int nErrorCode) v4Gk
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{ ,'}ZcN2)  
System.err.println("Error Code : " + nErrorCode); #B
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} k2a^gCBC  
7[PXZT
  
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//停止文件下载 *{bqHMd4L  
public void siteStop() 5irOK9hK  
{ }K\_N]#6n  
bStop = true; %|~UNP$  
for(int i=0;i<nStartPos.length;i++) aJts  
fileSplitterFetch.splitterStop(); }#1{GhsS  
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} sQ$FtKm6  
} SE1 tlP  
//负责部分文件的抓取 6>Fw,$  
**FileSplitterFetch.java H+Wd#7l,  
*/ *Bj G3Jc5  
package NetFox; -$rfu  
t+VPX2  
&W%TY:Da|  
import java.io.*;
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import java.net.*; $}829<gh7  
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public class FileSplitterFetch extends Thread { ;-F#a+2]!  
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??Lxb% 7R  
String sURL; //File URL }`X$ '  
long nStartPos; //File Snippet Start Position XN Y(@  
long nEndPos; //File Snippet End Position ,DjZDw  
int nThreadID; //Thread's ID K:0RP?L  
boolean bDownOver = false; //Downing is over "v06Fj>q  
boolean bStop = false; //Stop identical j8b:+io  
FileAccessI fileAccessI = null; //File Access interface 6
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9f "*Oj  
{ m-:k]9I  
this.sURL = sURL; x8H)m+AW  
this.nStartPos = nStart; +1Uw<~  
this.nEndPos = nEnd; Kfi A 7W  
nThreadID = id; _
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 psMagzr&)e  
} 1_'ZbZv4h  
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public void run() [x&&N*>N  
{ P>H'od  
while(nStartPos < nEndPos && !bStop) `yhL11]~  
{ ecb[m2z  
*6h.#$\  
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try{ Lh+^GQ  
URL url = new URL(sURL); 0YS*=J"7z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pyNPdEy  
httpConnection.setRequestProperty("User-Agent","NetFox"); &^}w|J?  
String sProperty = "bytes="+nStartPos+"-"; {BJxRH"&6*  
httpConnection.setRequestProperty("RANGE",sProperty); BH}u\K  
Utility.log(sProperty); @/9> /?JP  
NzEuiI}  
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InputStream input = httpConnection.getInputStream(); Mfgd;FsX#  
//logResponseHead(httpConnection); 1q*3
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fF9vV. }  
byte[] b = new byte[1024]; m\t %wr  
int nRead; jQc0_F\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 29E^]IL?  
{ {{O1C~  
nStartPos += fileAccessI.write(b,0,nRead); | o?@Eh  
//if(nThreadID == 1) h7*m+/O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q[+];  
} JeO(sj$e  
6Us#4 v,  
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Utility.log("Thread " + nThreadID + " is over!"); uv@4/M`  
bDownOver = true; |ey6Czm  
//nPos = fileAccessI.write (b,0,nRead); Q=+KnE=h  
} iQA f  
catch(Exception e){e.printStackTrace ();} E)`+1j  
} fQv^=DI#  
} G6I>Ry[2?  
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//打印回应的头信息 < B'BlqTS  
public void logResponseHead(HttpURLConnection con)
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{ l{;vD=D  
for(int i=1;;i++) IQR?n}ce  
{ v67o>`<$  
String header=con.getHeaderFieldKey(i); TEY%OIzU+  
if(header!=null) \s,ZE6dQ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); nlJxF5/  
Utility.log(header+" : "+con.getHeaderField(header)); #wt#-U;  
else 0{ \AP<  
break; l2$6ojpo  
} R7vO,kZ6Q  
} GUMO;rZs  
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public void splitterStop() Z5+qb  
{ 'sJYt^  
bStop = true; wVp  
} AuWEy-q?  
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@<l7"y;\  
} 
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IRD?.K]*  
/* ]x?`&f8i  
**FileAccess.java iFpJ/L  
*//文件访问(定位，写) /JJU-A(  
package NetFox; rtC.!].;%  
import java.io.*; A[^fG_l
4  
1^$ vmULj  
}fdo Aid~  
public class FileAccessI implements Serializable{ F~4oPB K<  
66!cfpM  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 n YWS'i@  
RandomAccessFile oSavedFile; XJ.b
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long nPos; 9*U3uyPi  
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public FileAccessI() throws IOException xXQDHc-Ba  
{ .gzNdSE  
this("",0); -ich N/U]s  
} ~{/"fTif  
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public FileAccessI(String sName,long nPos) throws IOException Kj.4Z+^  
{ :*k  
oSavedFile = new RandomAccessFile(sName,"rw"); f+d
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this.nPos = nPos; cA m>f[  
oSavedFile.seek(nPos); TldqF BX  
} h0_od/D1r  
5R"iF+p4  
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public synchronized int write(byte[] b,int nStart,int nLen) BUvE~l.,|  
{ ^`?2g[AA  
int n = -1; Rf9;jwU  
try{ o-H\vtOjE  
oSavedFile.write(b,nStart,nLen); !,WO]Ov  
n = nLen; Po_y78ZD  
} [+j}:u  
catch(IOException e) }]V
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{ Ti:PKpc  
e.printStackTrace (); x/7kcj!O  
} 3g ep_aC  
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-q'G]}  
return n; N/CL?Z>c  
} 6
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} Pk)>@F<  

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/* K;)(fc  
**SiteInfoBean.java !79eF)  
*/ KUD&vqx3  
package NetFox; cCa+UTxaJ  
lFJDdf2:$C  
.!
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public class SiteInfoBean { 3&`LVhx  
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1xBgb/+  
private String sSiteURL; //Site's URL `|&#=hl~  
private String sFilePath; //Saved File's Path 9fQ[:Hl"  
private String sFileName; //Saved File's Name \P~h0zg?  
private int nSplitter; //Count of Splited Downloading File  VB&`S+-  
s
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public SiteInfoBean() dQ#$(<v[  
{//nSplitter的缺省值为5 lf2Q  
//default value of nSplitter is 5 (Y!{ UNq5  
this("","","",5); .30eO_msK  
} M1HGXdN*B  
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y\?NB:=%  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KATu7)e&~^  
{ O n/q&h5  
sSiteURL= sURL; xu<oQBt  
sFilePath = sPath; qe[P'\]L  
sFileName = sName; AJYZ`  
this.nSplitter = nSpiltter; 0+
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Yx[B*] 2  
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} ~8 S2BV3@  
8{4SaT.-Rm  
rK~Obv  
public String getSSiteURL()
taBCE?{  
{ 2I$-&c]  
return sSiteURL; O_4j"0  
} %LjhK,'h  
}}b &IA#  
$*$X5  
public void setSSiteURL(String value) X+KQ%Efo  
{ 9M;k(B!  
sSiteURL = value; CaB@,L  
} B%(-UTQf  
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;&9wG`  
public String getSFilePath() +'V ,z  
{ Lq#$q>!K  
return sFilePath; ]k)h<)nY  
} jI!WE$dt  
UFPSQ  
ZTzh[2u*  
public void setSFilePath(String value) AGMrBd|J{  
{ z8JdA%YBM  
sFilePath = value; !n3J6%b9y/  
} U2CCjAgRs  
fI }v}L^  
l<-0@(x)  
public String getSFileName() 1kczlTF  
{ 3?r?)$Jk  
return sFileName; NR.YeKsBq  
} J_7&nIH7  
><w=  
Evt&N)l!^  
public void setSFileName(String value) ~#PC(g  
{ a&C}'e"  
sFileName = value; #,;X2%c  
} d: LP8  
ICm/9Onh&  
JAU:Wqlg1  
public int getNSplitter() I%tJLdL  
{ -+Gd<U$  
return nSplitter; Zp_v
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} j6#RV@ p`  
M?.[Rr-uw  

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public void setNSplitter(int nCount) fl*>m,  
{ L9^h.Y7  
nSplitter = nCount; p -wEPC0  
} |YWX.-aeo  
} ]vUTb9>{?  
?X~U[dV?  
&-2i+KjEX  
/* ES9|e
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**Utility.java B`/p

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*/ >*e,+ok  
package NetFox; 7yFV.#K3O  
69JC!du  
ST25RJC  
public class Utility { -=VGXd  
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public Utility() ]x^v;r~  
{ +@jX|  
zMbz_22*  
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} K[M[0D  
~[3B<^e  
//线程睡眠 oa:30@HSb  
public static void sleep(int nSecond) KV]8o
'  
{ K-,8~8[  
try{ Gb_y"rx?0  
Thread.sleep(nSecond); rBrJTF:
.  
} <ecif_a=m  
catch(Exception e) +"F9yb  
{ ht5eb"c+8  
e.printStackTrace (); qgk6 \&K[  
} &M2SqeR62;  
} W=ar&O~}n  
~E*`+kD  
//日志 ~CQTPR  
public static void log(String sMsg) ~|.vz!A  
{ 7^*[XH  
System.err.println(sMsg); jw$[b=sa  
} u
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9Netnzv%  
a[A9(Ftn  
public static void log(int sMsg) XXA1%Lw%  
{ t%Hy#z1W_  
System.err.println(sMsg); '/v@q]!  
} <j^bk"l p  
} |}KNtIX\G  
_5JwJcQ  
bj`mQMC  
/* <yz&> +9,  
**TestMethod.java d/!R;,^  
*/ ExJexjOWI^  
package NetFox; Fg<rz&MR  
/`vn/X^?^  
3r]N\c  
public class TestMethod { 1Kc[).O1  
+`s%-}-r  
QGpAG#M9?  
public TestMethod() mH\eJ  
{ ///xx/weblogic60b2_win.exe Q{"QpVY8  
try{ eSlZAdK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q#!]5
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'I8K1Q=/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w]
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fileFetch.start(); rj> _L  
} SFQYrY  
catch(Exception e){e.printStackTrace ();} h(1o!$EU2  
WjVj@oC  
4A@77#:J5  
} TqN4OkCm/  
@Wb_Sz4`  
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public static void main(String[] args) jDwLzvMO  
{ <JNiW8 PG  
new TestMethod(); y+g01z  
} SB#Y^!  
} z6+D=<  
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