http断点续传简单实现（java)

/* 7W6tz\Y  
**SiteFileFetch.java %W=S*"e-  
*/ MkG3TODfHB  
package NetFox; EC2KK)=n}  
import java.io.*; sHSZIkB-r  
import java.net.*; {
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public class SiteFileFetch extends Thread { G_{x)@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean S$Tc\/{  
long[] nStartPos; //开始位置 ,25Qhz]  
long[] nEndPos; //结束位置 (7G5y7wI"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y1!c:&  
long nFileLength; //文件长度 {i)k#`  
boolean bFirst = true; //是否第一次取文件 t8,s]I&  
boolean bStop = false; //停止标志 ~*9 vn Z@  
File tmpFile; //文件下载的临时信息 v_PhJKE  
DataOutputStream output; //输出到文件的输出流 8o-*s+EY"&  
0 V
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'PF?D
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public SiteFileFetch(SiteInfoBean bean) throws IOException eDR4c%  
{ -9)<[>:  
siteInfoBean = bean; F'DO46  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X|)Ox ,(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  g-MaP  
if(tmpFile.exists ()) z^to"j  
{ GpV
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bFirst = false; 5 iUT#  
read_nPos(); 1CFTQB>  
} o/bmS57  
else ~{hcJ:bI  
{ _6v|k}tW'Y  
nStartPos = new long[bean.getNSplitter()]; E`3yf9"  
nEndPos = new long[bean.getNSplitter()]; UGK4uK+I`  
} ^b=9{.5  
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} ,rT62w*e  
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public void run() pZx'%-\-T  
{ $bRakF1'S  
//获得文件长度 ?+)O4?#  
//分割文件 c0.
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//实例FileSplitterFetch fJ_d,4  
//启动FileSplitterFetch线程 ;ZMm6o  
//等待子线程返回 s+;J`_M  
try{ l(D
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if(bFirst) a%a_sR\)  
{ :!a'N3o>  
nFileLength = getFileSize(); 2`qO'V3Q  
if(nFileLength == -1) PMzPe"3M  
{ vs-%J6}G  
System.err.println("File Length is not known!"); j_\nsM7  
} x}t,v
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else if(nFileLength == -2) T >XnVK  
{ u-g2*(ZT  
System.err.println("File is not access!"); ;v0M ::  
} aV?dy4o$  
else ^sR]w]cz.  
{ eHUr!zH:  
for(int i=0;i<nStartPos.length;i++) 6KuB<od  
{ >h+[#3vD  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a[;TUc^I1F  
} z DDvXz  
for(int i=0;i<nEndPos.length-1;i++) I^>m-M.  
{ gPs%v`y)*D  
nEndPos = nStartPos[i+1]; +cS%b}O`$  
} ?}4 =A&][  
nEndPos[nEndPos.length-1] = nFileLength; ,f ..46G  
} k*)O]M<,  
} EHk(\1!V  
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7#K%Bo2pG  
//启动子线程 5g9lO]WDI  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fx&b*OC  
for(int i=0;i<nStartPos.length;i++) 3n{
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{ [J4 Aig  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #jdo54-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), U40adP? a  
nStartPos,nEndPos,i); VJ1(|v{D4[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); {k.Dy92  
}  wfr+-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WVaIC$Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~ KNdV  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6")co9  
nEndPos = " + nFileLength); F0,
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// fileSplitterFetch[nPos.length-1].start(); V\k?$}  
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//等待子线程结束 C1 qyjlR  
//int count = 0; 4j9  
//是否结束while循环 .{6?%lt  
boolean breakWhile = false; V. sIiE  
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Fa]fSqy@;  
while(!bStop) Wl3jbupu _  
{ GtZkzVqLd  
write_nPos(); XI6LPA0%  
Utility.sleep(500); XRU^7@Ylks  
breakWhile = true; - zaqL\  
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for(int i=0;i<nStartPos.length;i++) U'IJwGRP  
{ `V N $ S  
if(!fileSplitterFetch.bDownOver) /rRQ*m_  
{ JI1O(  
breakWhile = false; Z,~"`9>Ss  
break; n ,<`.^  
} 6 isz  
} [E_+fT  
if(breakWhile) QInow2/u  
break; {bF95Hs-  
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i*16kdI.  
//count++; !6:q#B*  
//if(count>4) Pw4j?pv2  
// siteStop(); i?^Cc\gH  
} F
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System.err.println("文件下载结束！"); o^59kQT  
} m.~&n!1W*`  
catch(Exception e){e.printStackTrace ();} R#Z1+&='  
} iR-MuDM  
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//获得文件长度 {b@rQCre7  
public long getFileSize() M4a-+T"  
{ f[)_=T+  
int nFileLength = -1; _`!@  
try{ *"E?n>b  
URL url = new URL(siteInfoBean.getSSiteURL()); >/
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AR\?bB~`c  
httpConnection.setRequestProperty("User-Agent","NetFox"); SM:SxhrGt  
;S+c<MSl  

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int responseCode=httpConnection.getResponseCode(); 3Lwl~h!  
if(responseCode>=400) ;K?fAspSH  
{ FAu G`zu  
processErrorCode(responseCode); :)nn/[>fC  
return -2; //-2 represent access is error t"1'B!4  
} @]f"X>  
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String sHeader; V|NWJ7  
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for(int i=1;;i++) vCwDE~  
{ zY8"\ZB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); lh*m(  
//Utility.log(in.readLine()); o}5:vi
]  
sHeader=httpConnection.getHeaderFieldKey(i); {xt<`_R  
if(sHeader!=null) #&">x7?5  
{ ~c!zTe  
if(sHeader.equals("Content-Length")) c1/Gyq  
{ e4NT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U-TwrX  
break; w_^&X;0^  
} W0$G7s  
} !?tWWU%P)  
else :^kP?  
break; CTtF=\  
} `<t{NJ&f  
} l3}n.ODA  
catch(IOException e){e.printStackTrace ();} S$]:3  
catch(Exception e){e.printStackTrace ();} QN-n9f8  
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Utility.log(nFileLength); xpyb&A  
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return nFileLength; GMU<$x8o  
} *cp|lW!ag  
#2DH_P  
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//保存下载信息（文件指针位置） @.*[CC;&  
private void write_nPos() ~<, \=;b/  
{ vFb{(gIJ  
try{ [CPZj*|b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `#fOY$#XB  
output.writeInt(nStartPos.length); _DC/`_'  
for(int i=0;i<nStartPos.length;i++) g)$Pvfc  
{ |[K7oa~#  
// output.writeLong(nPos); K@n.$g  
output.writeLong(fileSplitterFetch.nStartPos); NOx&`OU
+  
output.writeLong(fileSplitterFetch.nEndPos); /BT;Q)(&  
} kRiWNEw  
output.close(); }(E6:h;}~  
} '! 1ts@  
catch(IOException e){e.printStackTrace ();} -f9M*7O<gf  
catch(Exception e){e.printStackTrace ();} zwU8iVDe  
} uc Z(D|a   
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//读取保存的下载信息（文件指针位置） 8fM}UZI  
private void read_nPos() 1>%SSQ  
{ S$+ v?Y`)  
try{ Ynz^M{9)K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3!Qt
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int nCount = input.readInt(); ts;_T..L  
nStartPos = new long[nCount]; ";s5It  
nEndPos = new long[nCount]; --.j&w  
for(int i=0;i<nStartPos.length;i++) Qb|w\xT^Y  
{ ?qO,=ms>-  
nStartPos = input.readLong(); YfMe69/0I  
nEndPos = input.readLong(); EE
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} -&)^|Atm  
input.close(); ,;+\!'lS  
} Nr`nL_DQ  
catch(IOException e){e.printStackTrace ();} lR.a3.~  
catch(Exception e){e.printStackTrace ();} {+xUAmd  
} 1.,mNY^UN  
d`~#uN {  
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private void processErrorCode(int nErrorCode) c+a f=ac  
{ ]3={o3[:  
System.err.println("Error Code : " + nErrorCode); i"rMP#7  
} R1Pnj
 
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//停止文件下载 j%p~.kW5  
public void siteStop() ]`. d%Vx  
{ ~|uCZ.;o  
bStop = true; w|L~+   
for(int i=0;i<nStartPos.length;i++) !'{j"tv  
fileSplitterFetch.splitterStop(); rB4#}+Uq  
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} ,6M-xSDs  
} A^K,[8VX  
//负责部分文件的抓取 M%B[>pONb7  
**FileSplitterFetch.java l
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*/ e-e{-pB6  
package NetFox; 5)nv  
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)
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import java.io.*; BB%(!O4Dl  
import java.net.*; LpmspIPvf  
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public class FileSplitterFetch extends Thread { mr('zpkRq  
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String sURL; //File URL h[Iu_#HMa  
long nStartPos; //File Snippet Start Position :.35pp,0  
long nEndPos; //File Snippet End Position ("lcL2Bq  
int nThreadID; //Thread's ID ?1N0+OW  
boolean bDownOver = false; //Downing is over y:42H tS  
boolean bStop = false; //Stop identical 19N:9;Ixz  
FileAccessI fileAccessI = null; //File Access interface xJ"Zg]d{  
/ruf1?\,R  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8^R>y  
{ lwY{rWo  
this.sURL = sURL; > T-O3/KN  
this.nStartPos = nStart; j}VOr >xz  
this.nEndPos = nEnd; ##s!-.T  
nThreadID = id; 6sZRR{'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J.nVEqLZ  
} xlwsZm{V  
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public void run() N)!v-z,k  
{ I!(
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while(nStartPos < nEndPos && !bStop) ky~x4_y5  
{ &(rd{j/*  
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try{ Z~c7r n  
URL url = new URL(sURL); ^=W&p%Y(!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0ay!tS dN  
httpConnection.setRequestProperty("User-Agent","NetFox"); =#V11j  
String sProperty = "bytes="+nStartPos+"-"; Z|/):nVP7  
httpConnection.setRequestProperty("RANGE",sProperty); (mD]}{>  
Utility.log(sProperty); SW; bE  
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InputStream input = httpConnection.getInputStream(); sY6'y'a95  
//logResponseHead(httpConnection); 5r
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= ]@xXVf/  
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byte[] b = new byte[1024]; %nCUct@c  
int nRead; nB]Q^~jX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) X,N@`  
{  \1MDCP9:  
nStartPos += fileAccessI.write(b,0,nRead); +,-rb  
//if(nThreadID == 1) {+[gf:Ev  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  qN QsU  
} {Psj#.qP1  
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~ZNhU;%YW  
Utility.log("Thread " + nThreadID + " is over!"); y?JbJ  
bDownOver = true; yJL"uleRT  
//nPos = fileAccessI.write (b,0,nRead); EsWszpRqb  
} g.]'0)DMW  
catch(Exception e){e.printStackTrace ();} ]Bsq?e^  
} .UYpPuAkn  
} w7D:0SGD  
e
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//打印回应的头信息 S|J8:-  
public void logResponseHead(HttpURLConnection con) bVx]r[  
{ IYO,/ kbf  
for(int i=1;;i++) CHU'FSq!  
{ **q/'K  
String header=con.getHeaderFieldKey(i); %PS-nF7v  
if(header!=null) A;!FtD/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); bS'r}  
Utility.log(header+" : "+con.getHeaderField(header)); )q^vitkjup  
else ^pjez+  
break; 2o$8CR;  
} %:,=J  
} gQEV;hCO  
!LJ.L?9qw  
J50 ~B3bj`  
public void splitterStop() %_[-[t3  
{ 9y5\4&v  
bStop = true; ]xG8vy  
} yq}{6IyZ^  
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~ YK<T+  
} SIlg  
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/* @5y(>>C}8%  
**FileAccess.java
l0&8vhw8k  
*//文件访问(定位，写) `Ek!;u>  
package NetFox; KVR}Tp/R  
import java.io.*; )^\='(s  
!{Y#<tG]  
752wK|o0|;  
public class FileAccessI implements Serializable{ vdm?d/0(^  
wB)+og-^1f  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 is(!_Iv  
RandomAccessFile oSavedFile; \uk#pL  
long nPos; 9^^#I~-  
$<cZ<g5)  
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public FileAccessI() throws IOException ;*2e;m~)?  
{ gQuw|u  
this("",0); L0kNt &di  
} vb- 
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?I'-C?(t@1  
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public FileAccessI(String sName,long nPos) throws IOException Hl;p>>n  
{ BFOFes`>~  
oSavedFile = new RandomAccessFile(sName,"rw"); j/<y  
this.nPos = nPos;  J31M:<  
oSavedFile.seek(nPos); tA-B3 ]  
} #Qr4Ke$g[l  
JP4Moq~r   
pQ 6#L  
public synchronized int write(byte[] b,int nStart,int nLen) f~FehN7  
{ U!/nD~A  
int n = -1; b8.%?_?  
try{ YfwJBzD  
oSavedFile.write(b,nStart,nLen); #mhD; .Wg  
n = nLen; Qs9U&*L  
} rk/ c  
catch(IOException e) EY
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{ dz|*n'd  
e.printStackTrace (); pq3 A%|  
} wzPw;
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return n; ~n^G<iXLp  
} 0f%:OU5Y  
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} {z/^X<T  
9.zQ<k2  
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/* E`fssd~  
**SiteInfoBean.java yim$y,=d  
*/ /:` i%E  
package NetFox; pPqN[OJ  
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public class SiteInfoBean { huJq#5?  
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private String sSiteURL; //Site's URL ,/6:b
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private String sFilePath; //Saved File's Path +MZO%4  
private String sFileName; //Saved File's Name X8 )>}#:  
private int nSplitter; //Count of Splited Downloading File bH/pa#G(  
1?RCJ]e5  
4)HWPX  
public SiteInfoBean() ZQ9oZHUm  
{//nSplitter的缺省值为5 )H9*NB8%  
//default value of nSplitter is 5 (oitC
IV  
this("","","",5); G>,nZ/,A{  
} %lJiM`a  
5@D7/$bLp  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yVI;s|jG  
{ tOg 8L2  
sSiteURL= sURL; [A9,!YY  
sFilePath = sPath; sV^h#g~Zb
 
sFileName = sName; p/1}>F|i  
this.nSplitter = nSpiltter; V$<G)dwUG5  
%?oU{KzQ@;  
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} //M4Sq(  
:aq>  
/QXs-T}d  
public String getSSiteURL() pR6A#DgB  
{ '}+X,Usm  
return sSiteURL; LAY)">*49H  
} Flujwh@rg  
k,R~oSA'n  
z3Y)-  
public void setSSiteURL(String value) j]B$(pt  
{ te*Y]-&I|/  
sSiteURL = value; <,pLW~2-"  
} C6'*/wq  
o`K^Wy~+k#  
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public String getSFilePath() kE_@5t7O{  
{ HS`bto0*  
return sFilePath; Gr#rM/AfCK  
} ZC5Yve8  
^s@*ISY  
;2Ad])  
public void setSFilePath(String value) ju^"vw  
{ 5Vqmv<F;$Z  
sFilePath = value; *[xNp[
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} dI0
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public String getSFileName() Iwt2}E(e  
{ @b!R2Yq  
return sFileName; "dK
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} ^Em@6fz[  
P\X=*  
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public void setSFileName(String value) {{]=zt|69  
{ /y](mu"!  
sFileName = value; 6PJJ?}P^1  
} "_1-IE  
)qyx|D  
~f=6?5.wa  
public int getNSplitter() moVa'1ul  
{ g;-+7ViIr  
return nSplitter; G{f`K^  
} g2aT`=&Z  

w{r(F`  
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public void setNSplitter(int nCount) ,dZ H$  
{ (]}x[F9l  
nSplitter = nCount; ?BDlB0jxzi  
} XY!{g(  
} _ 7BF+*T  
nG},v%  
6>=-/)p}  
/* $ o5V$N D  
**Utility.java T^'*_*m  
*/  ?+ -/';  
package NetFox; FI`nRFq)C  
(pE\nuA\  
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public class Utility { Th~3mf #  
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public Utility() Y|m_qB^_  
{ qD(fYOX{C  
bIb6yVnHi  
)e|$K= D  
} k+WO &g*|  
*#Lsjk~_-  
//线程睡眠 C`NBHRa>  
public static void sleep(int nSecond) V4`:Vci Aw  
{ Ms:KM{T0  
try{ 5w,lw  
Thread.sleep(nSecond); *or2  
} _'!N q  
catch(Exception e) L876$  
{ $ ]W[y=  
e.printStackTrace (); vLv|SqD  
} yN9$gfJC^  
} <OR.q  
`W"a!,s2  
//日志 ;#Jq$v)D  
public static void log(String sMsg) J.bFv/R  
{ 0<]$v"`I  
System.err.println(sMsg); 7m|`tjQ1  
} @4/~~  
zj~nnfoys  
i
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public static void log(int sMsg) VM-qVd-  
{ .N5hV3  
System.err.println(sMsg); s6uF5]M;2  
} uQ[vgNe*m  
} ,zAK3d&h
j  
bU;}!iVc]  
M
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/* +=ZWau   
**TestMethod.java :"M9*XeHO  
*/ -Q<z1vz  
package NetFox; t(J![wB}  
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+={  
public class TestMethod { *F\T}k7  
mJ0}DJiX$  
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public TestMethod() g(-;_j!=  
{ ///xx/weblogic60b2_win.exe Ci]'G>F@"  
try{ tMxsR>sH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F5FNhuC  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Zz"I.$$[M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Rro?q   
fileFetch.start(); h]kn%?fpmB  
} Z"6 2#VM  
catch(Exception e){e.printStackTrace ();} cr76cYq"Q  
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} cJxW;WI!,  
d{QMST2&  
&_"ORqn&  
public static void main(String[] args) SX1X<9  
{ o2
;(VSKhS  
new TestMethod(); \p5|}<Sr)  
} zb"rMzCH  
} SQh+5  
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