http断点续传简单实现（java)

/* {%v{iE>  
**SiteFileFetch.java XAUHF-"WE  
*/ 5Kkp1K$M  
package NetFox; qc/)l~]?g{  
import java.io.*; 'DB'lP  
import java.net.*; ~#:R1~rh\e  
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public class SiteFileFetch extends Thread { }ho6  
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SiteInfoBean siteInfoBean = null; //文件信息Bean A{wSO./3  
long[] nStartPos; //开始位置 %xwtG:IKEV  
long[] nEndPos; //结束位置 NvJ}|w,Z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `6Yk-5  
long nFileLength; //文件长度 p~<d8n4UH  
boolean bFirst = true; //是否第一次取文件 O<+x=>_  
boolean bStop = false; //停止标志 9{R88f
?;  
File tmpFile; //文件下载的临时信息 (+.R8  
DataOutputStream output; //输出到文件的输出流 {xQ(xy  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） gYa (-o  
public SiteFileFetch(SiteInfoBean bean) throws IOException n{z!L-x^b  
{ RA:3ZV  
siteInfoBean = bean; e8hwXz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >^adxXw.o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hODq&9!  
if(tmpFile.exists ()) F t;[>o  
{ 9
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bFirst = false; 6z1>(Za7>  
read_nPos(); <w0$0ku  
} 'zx1kq1  
else `;3fnTI:1  
{ O.'\GM  
nStartPos = new long[bean.getNSplitter()]; b[my5Ol  
nEndPos = new long[bean.getNSplitter()]; ka| 8 _C^z  
} @l&>C#K\  
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} 6cTd
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public void run() *l8:%t\  
{ =U3rOYbP;  
//获得文件长度 _iZ9Ch\  
//分割文件 b,-qyJW6  
//实例FileSplitterFetch Y~-P9  
//启动FileSplitterFetch线程 ck#MpQ!An  
//等待子线程返回 uzaDK  
try{ h$a%PaVf  
if(bFirst) nCdxn#|  
{ mI3 \n  
nFileLength = getFileSize(); f VpE&F  
if(nFileLength == -1) (-hGb:  
{ 5c6?$v/  
System.err.println("File Length is not known!"); kTS#>uS  
} ~cW,B}  
else if(nFileLength == -2) +{H
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{ \WZ]'o6  
System.err.println("File is not access!"); >vc$3%L[$  
} ,(Nr_K  
else qBcwM=R3P  
{ U<.,"`=l  
for(int i=0;i<nStartPos.length;i++) $g]'$PB  
{ (b;*8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 'mE!,KeS;  
} hd_<J]C  
for(int i=0;i<nEndPos.length-1;i++) FKk.BA957h  
{ nY50dFA,  
nEndPos = nStartPos[i+1]; TCetd#;R  
} #'oGtFCd`  
nEndPos[nEndPos.length-1] = nFileLength; iCh,7I,m  
} 6@geakq  
} ^z}$'<D9  
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//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; H+F>#  
for(int i=0;i<nStartPos.length;i++) S3.76&  
{ geSH3I   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f|'8~C5I@>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @0U={qX  
nStartPos,nEndPos,i); h5VZ-v_j  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F4 :#okt  
fileSplitterFetch.start(); FR? \H"'x  
} 2H2Yxe7?-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PNh
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ad,pHJ`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >}6V=r3[+  
nEndPos = " + nFileLength); 5 p! rZ  
// fileSplitterFetch[nPos.length-1].start(); hSF4-Vvb  
clO9l=g  
h!q_''*;  
//等待子线程结束 oS Apa  
//int count = 0; <t"|wYAa_  
//是否结束while循环 OCN@P+L3q  
boolean breakWhile = false; wJu,N(U  
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while(!bStop) 
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{ >`=<(8bu  
write_nPos(); Vs@H>97,
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Utility.sleep(500); J0O wzO  
breakWhile = true; Hw 1cc3!  
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for(int i=0;i<nStartPos.length;i++) /O&{fo  
{ ,RIC _26  
if(!fileSplitterFetch.bDownOver) B"=w9w]  
{ fH*1.0f]6  
breakWhile = false; 9KGi%UIFvn  
break; Uy
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} #jd&f,Tt  
} m9 D'yXZ  
if(breakWhile) ]c~W$h+F  
break; IJ#+"(?7,u  
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//count++; $hq'9}ASOL  
//if(count>4) 5><KTya?=  
// siteStop(); l/g6Tv`w  
} mVNHH!  
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System.err.println("文件下载结束！"); @z1pE@7jK  
} kYnp$8  
catch(Exception e){e.printStackTrace ();} y,cz;2  
} s?~lM
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//获得文件长度 W~qVZ(G*U  
public long getFileSize() y';"tDFb  
{ K4K]oT  
int nFileLength = -1; } za"rU  
try{ c=#V*<  
URL url = new URL(siteInfoBean.getSSiteURL()); :oO ?A
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L wP  
httpConnection.setRequestProperty("User-Agent","NetFox"); ['jr+gIfQ  
x_$`#m{hL5  
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int responseCode=httpConnection.getResponseCode(); \^]*T'>b  
if(responseCode>=400) ?`T-A\A=  
{ GW\66$|  
processErrorCode(responseCode); J`xCd/G  
return -2; //-2 represent access is error w~wg[d  
} "'v^X!"  
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String sHeader; S\R5SRE  
+ [~)a4#  
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for(int i=1;;i++) N97
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{ `Y_G*b.Rm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8Ai\T_l  
//Utility.log(in.readLine()); g#b9xTGJ^  
sHeader=httpConnection.getHeaderFieldKey(i); r2G38/K  
if(sHeader!=null) +sFpIiJg  
{ =>htX(k}  
if(sHeader.equals("Content-Length")) %:e.E
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{ !yo@i_1D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z=yE- I{  
break; i)th] 1K%  
} am+w<NJ(us  
} P^[y~I#{  
else _bn "c@s  
break; 9
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} 0S2/,[-u+  
} K7c[bhi_w  
catch(IOException e){e.printStackTrace ();} |qz&d=>  
catch(Exception e){e.printStackTrace ();} {@ Z=b5/P  
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Utility.log(nFileLength); X+kgx!u'y  
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return nFileLength; 5jAS1XG  
} %00cC~}4  
2;ju/9x  
"/nbcQ*s*E  
//保存下载信息（文件指针位置） %&j\:X~A  
private void write_nPos() 3@42uG>  
{ r1[c+Hy  
try{ J#xZ.6)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); b} FhC"'i  
output.writeInt(nStartPos.length); %ty`Oa2  
for(int i=0;i<nStartPos.length;i++) 7KL@[  
{ mI'&!@WG  
// output.writeLong(nPos); -car>hQq  
output.writeLong(fileSplitterFetch.nStartPos); s w
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output.writeLong(fileSplitterFetch.nEndPos); o[)*Y`xq<w  
} qs!A)H#  
output.close(); i2+_~$f  
} *Gul|Lp$<I  
catch(IOException e){e.printStackTrace ();} ]-;M
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catch(Exception e){e.printStackTrace ();} =SD^Jl{H  
} mgMa)yc!dp  
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//读取保存的下载信息（文件指针位置） {5]c\_.  
private void read_nPos() +w/B3b  
{ b/?)_pg  
try{ Xo$SQ0K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mDx=n.lIz  
int nCount = input.readInt(); 83J63Xa  
nStartPos = new long[nCount]; 28qlp>U  
nEndPos = new long[nCount]; ![9$ru  
for(int i=0;i<nStartPos.length;i++) 6aLRnH"Ud  
{ ^?NLA&v<  
nStartPos = input.readLong(); AuT:snCzR  
nEndPos = input.readLong(); ]>
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} 8([ MR  
input.close(); c:aW"U   
} C8x9 Jrc  
catch(IOException e){e.printStackTrace ();} -Fq`#"  
catch(Exception e){e.printStackTrace ();} G*_qqb{B  
}  &Ufp8[  
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private void processErrorCode(int nErrorCode) [&g"Z"  
{ ,0c]/Sd*p  
System.err.println("Error Code : " + nErrorCode); pu5%$}dBE  
} q@g#DP+C  
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//停止文件下载 ~ #7@;C<nt  
public void siteStop() Gt)ij?~  
{ w'E(9gV  
bStop = true; w{ ;Sp?Os  
for(int i=0;i<nStartPos.length;i++) rp+]f\]h  
fileSplitterFetch.splitterStop(); ..zX  
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} HX)]@qL  
} IXG@$O?y/  
//负责部分文件的抓取 N0%q66]1  
**FileSplitterFetch.java et"Pb_-U  
*/ bB>.dC  
package NetFox; xS>vmnW  
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import java.io.*; 'iTY?  
import java.net.*; c8Q}m(bhWI  
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public class FileSplitterFetch extends Thread { KY}H-  
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String sURL; //File URL "7'P Lo3O  
long nStartPos; //File Snippet Start Position s/B_  
long nEndPos; //File Snippet End Position :dpwr9)  
int nThreadID; //Thread's ID !FDd5CS  
boolean bDownOver = false; //Downing is over I,<?Kv  
boolean bStop = false; //Stop identical =Z{jc  
FileAccessI fileAccessI = null; //File Access interface ?J,,RK.  
@meT8S9t  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException TMo DN%{  
{ T@*'}*  
this.sURL = sURL; y$9! rbL  
this.nStartPos = nStart; 3H0B+F2XQ  
this.nEndPos = nEnd; ``eam8Az_U  
nThreadID = id; jijwHL  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 YWs?2I  
} :Nv7Wt!  
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public void run() M
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{ -Lu&bVt<>  
while(nStartPos < nEndPos && !bStop) R}cNhZC  
{ .xuzu#-  
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try{ $wi4cHh  
URL url = new URL(sURL); _6V1oe2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iEZ+Znon  
httpConnection.setRequestProperty("User-Agent","NetFox"); m[KmXPFht1  
String sProperty = "bytes="+nStartPos+"-"; JXMH7  
httpConnection.setRequestProperty("RANGE",sProperty); lx=tOfj8  
Utility.log(sProperty); ]%y>l j?Y  
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InputStream input = httpConnection.getInputStream(); ~\8(+qIv%f  
//logResponseHead(httpConnection); i/skU9  
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byte[] b = new byte[1024]; 0Sz[u\w  
int nRead; s5rD+g]E`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @"MQ6u G>  
{ ]ly" K!1,  
nStartPos += fileAccessI.write(b,0,nRead); tv.<pP9-C  
//if(nThreadID == 1) f*B
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yi*EobP  
} A=5Ebu!z  
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Utility.log("Thread " + nThreadID + " is over!"); Eh ";irE  
bDownOver = true; $xbW*w  
//nPos = fileAccessI.write (b,0,nRead); k}
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} =#,`k<v%I  
catch(Exception e){e.printStackTrace ();}
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} IhBc/.&RL  
} e).;;0  
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/KX+'@  
//打印回应的头信息 ($kw*H{Ah^  
public void logResponseHead(HttpURLConnection con) \0d'y#Gp*  
{ BkGExz  
for(int i=1;;i++) E "}@SaB-  
{ L/r_MtN  
String header=con.getHeaderFieldKey(i); &=BzsBh  
if(header!=null) ?q9]H5\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [#q]B=JB  
Utility.log(header+" : "+con.getHeaderField(header));
-PAEJn5$O  
else |Ia9bg'1U  
break; p/?o^_s  
} 8"9&x} tl-  
} uT4|43< G  
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public void splitterStop() P|bow+4  
{ -]HZ?@  
bStop = true; * l1*zaE  
} ;_)~h$1%=  
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} 1QG q;6\  
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/* ft6)n T/"&  
**FileAccess.java 8zD>t~N2C  
*//文件访问(定位，写) !43!JfD  
package NetFox; l^9gFp~I  
import java.io.*; NBY|U{.g  
X<}}DZSu a  
PnA{@n\  
public class FileAccessI implements Serializable{ JRo/ HY+  
v/q-{1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,;6V=ok  
RandomAccessFile oSavedFile; /oHCV0!0  
long nPos; [jzsB:;XB&  
O*~z@"\  
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public FileAccessI() throws IOException < ,*\t  
{ > 0MP[  
this("",0); Z|uvrFa  
} ovTL'j!  
p>`rTaeZg  
Iz09O:ER  
public FileAccessI(String sName,long nPos) throws IOException () _RLA  
{ dA~:L`A|X  
oSavedFile = new RandomAccessFile(sName,"rw"); Oh*~+/u}q  
this.nPos = nPos; r |C.K  
oSavedFile.seek(nPos); 05q760I+  
} p8~lGuH  
!%,7*F(  
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public synchronized int write(byte[] b,int nStart,int nLen) phuiLW{&  
{ *9EwZwE_K  
int n = -1; Yt]`>C[|D  
try{ 2!J#XzR0W  
oSavedFile.write(b,nStart,nLen); II=`=H{  
n = nLen; 7H  
} y9 {7+]  
catch(IOException e) Z^&G9I#  
{ ~R w1
 
e.printStackTrace (); T+}|$/Tv  
} 'K?h6?#  
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return n; 9efDM  
} &-yRa45?  
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} 8(%F{&<;  
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/* JX=rL6Y@:;  
**SiteInfoBean.java wf\"&xwh?  
*/ qPq]%G*{  
package NetFox; [<RhaZz  
x|~8?i$%  
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public class SiteInfoBean { $vegU]-R  
sN[}B{+  
)[Tm[o?Y.  
private String sSiteURL; //Site's URL rv*{[K  
private String sFilePath; //Saved File's Path |IcW7(  
private String sFileName; //Saved File's Name F] c\Qt  
private int nSplitter; //Count of Splited Downloading File '@t$3 hk  
T7,]^ 1  
`MOw\Z)..  
public SiteInfoBean()
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{//nSplitter的缺省值为5 @sLN  
//default value of nSplitter is 5 V!He2<  
this("","","",5); 2LtDS?)@  
} OX7=g$S 1  
hu}$\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P51M?3&=l  
{ R5uG.Oj-2  
sSiteURL= sURL; bw P=f.  
sFilePath = sPath; ,>a!CnK=  
sFileName = sName; 90Ki.K0  
this.nSplitter = nSpiltter; k:Pn.<  
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} /mex{+p>tO  
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public String getSSiteURL() {v|!];i  
{ ^1S{::  
return sSiteURL; k
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} )UKX\nD"0  
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7}X1A!1  
public void setSSiteURL(String value) %10ONe}  
{ }nd>SK4  
sSiteURL = value; H9*k(lnz`  
} >@2<^&K`  
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public String getSFilePath() ^9
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{ :V'99Esv`  
return sFilePath; "v1{  
} 5kiW@{m  
<w2h@ea  
}=-0DSLVj  
public void setSFilePath(String value) '=_(fa,  
{ yvYMk(LSF  
sFilePath = value; f% pT-#  
} *dw.=a9  
f{P1.?a  
X4V>qHV72  
public String getSFileName() 5#DMizv6  
{  i0=U6S:#  
return sFileName; pe?)AiTZ:  
} 2l<2srEK  
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#Z%" ?RJ  
public void setSFileName(String value) hq=;ZI  
{ |7|S>h^  
sFileName = value; 6'#5Dqw"r  
} TjUwe@&Rw  
.?:*0
 
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public int getNSplitter() =1IK"BA2?  
{ }DhqzKl  
return nSplitter; sW]_Ky.]  
} S1QMS  
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AF'<  
public void setNSplitter(int nCount) %(YQ)=w  
{ _?~%+Oz/  
nSplitter = nCount; T8^9*]:@c!  
} f^F;`;z  
} V 0Bl6  
&hYgu3O  
|:eTo<  
/* nTy]sPn  
**Utility.java 4aXIRu%#7  
*/ 1/}H 0\9'  
package NetFox; =-U0r$sK+F  
sO.MUj;  
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public class Utility { |}=eY?iXo  
#3&@FzD_P  
%qc_kQ5%  
public Utility() 6 s=VU\  
{ 9!( 8o  
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*tXyd<_
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} ^ij0<*ca9  
bZ`v1d (r  
//线程睡眠 K%z!#RyJ4  
public static void sleep(int nSecond) K\K& K~Z  
{ Hyb(.hlZh  
try{ 2K}49*  
Thread.sleep(nSecond); w!f2~j~  
} &;@L] o  
catch(Exception e) "jL>P)  
{ _Y; TS1u  
e.printStackTrace (); tV)CDA&Z  
} zgb$@JC  
} '_c/
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'z$N{p4
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//日志 7+HK_wNi  
public static void log(String sMsg) $TIeeTB  
{ v=llg ^  
System.err.println(sMsg); @v)Z>xv  
} Gx C+lqH#  
[^hW>O=@TN  
xM jn=\}  
public static void log(int sMsg) @| z _&E  
{ ~c)&9'  
System.err.println(sMsg); 26j<>>2  
} M$K%e  
} 5JzvT JMx  
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.QvD603%5  
/* m+c-"arIpA  
**TestMethod.java uxfh?gsL  
*/ DDrR9}k  
package NetFox; iH(7.?.r  
qAjtvc2  
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public class TestMethod { {$frR "K  
4"P9z}y=i  
o 4F'z  
public TestMethod() MPB[~#:  
{ ///xx/weblogic60b2_win.exe 7b"fpB  
try{ t
YjG8P#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }_+XN"}C  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {nmG/dn{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); # -'A =j  
fileFetch.start(); lod+]*MD  
} m.<_WXH  
catch(Exception e){e.printStackTrace ();} B!RfPk1B<*  
u zZ|0  
U^PXpNQ'  
} 3%POTAw%  
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public static void main(String[] args) -@N-i$!;J  
{ E+
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new TestMethod(); @\by`3*Q  
} xFu ,e  
} 0z=KnQx"4  
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