http断点续传简单实现（java)

/* #Yi,EwD  
**SiteFileFetch.java #q40 >)]  
*/ e!
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package NetFox; g<O*4 ]=  
import java.io.*; =YkJS%)M)  
import java.net.*; 
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public class SiteFileFetch extends Thread { +Ck F#H ~  
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SiteInfoBean siteInfoBean = null; //文件信息Bean cAIMt]_  
long[] nStartPos; //开始位置 4;WeB   
long[] nEndPos; //结束位置 D`PnY&ffT  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 RekTWIspT/  
long nFileLength; //文件长度 Gd1%6}<~  
boolean bFirst = true; //是否第一次取文件 g nJe!E  
boolean bStop = false; //停止标志 nJ |O,*`O  
File tmpFile; //文件下载的临时信息 t<sg8U.  
DataOutputStream output; //输出到文件的输出流 "knSc0,u  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /~V.qisZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException _@jBz"aq\  
{ LGZ5py=xb  
siteInfoBean = bean; KB!.N[!v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |ZW%+AQ|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SC)4u l%  
if(tmpFile.exists ()) l j*ELy  
{ 0{g@j{Lbz  
bFirst = false; !xyO  
read_nPos(); IO~d.Ra  
} 8v"tOa4D7  
else ork/:y9*y  
{ Y%:FawR  
nStartPos = new long[bean.getNSplitter()]; QPjmIO  
nEndPos = new long[bean.getNSplitter()]; uhvmh  
} Xm&L@2V  
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} YJ_`[LnL  
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public void run() FLdO  
{ \)859x&(  
//获得文件长度 "|w..%Wc  
//分割文件 BFmYb
K  
//实例FileSplitterFetch +hL+3`TD#H  
//启动FileSplitterFetch线程 yaV=e1W  
//等待子线程返回 {^gbS  
try{ 0 ;kcSz  
if(bFirst) peqoLeJI  
{ B MU@J  
nFileLength = getFileSize(); l^4[;%*f#l  
if(nFileLength == -1) Z#YkAQHv5  
{ 4} uX[~e&  
System.err.println("File Length is not known!"); |$@/ Z+  
} ^/\OS@CT\  
else if(nFileLength == -2) o8\@R  
{ IQ[?ej3W  
System.err.println("File is not access!"); bA\TuB  
} 4qo4g+  
else e:}8|e~T  
{ u38FY@U$  
for(int i=0;i<nStartPos.length;i++) -C.x;@!k  
{ 
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); GczGW4\P'  
} *A}QBZ  
for(int i=0;i<nEndPos.length-1;i++) fo~8W`H&  
{ NfcY30}:  
nEndPos = nStartPos[i+1]; ?z0f5<dL  
} Z0T{1YEJ  
nEndPos[nEndPos.length-1] = nFileLength; J
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} p%e!&:!  
} ?6.vd]oNO  
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//启动子线程 k+S+: 5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $@d`Kz;  
for(int i=0;i<nStartPos.length;i++) ,t5X'sY L  
{ GXB4&Q!C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _.0c~\VA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), e'aKI]>a  
nStartPos,nEndPos,i); NhQIpzL)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'JY*K:-  
fileSplitterFetch.start(); |8}f  
} AfW63;kH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =BJ/ZM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1) V,>)Ak  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }/BwFB+(/  
nEndPos = " + nFileLength); YfUdpa0  
// fileSplitterFetch[nPos.length-1].start(); cAC2Xq  
, RfU1R  
ep<Ad  
//等待子线程结束 2{c ;ELq  
//int count = 0; 6~GaFmW=  
//是否结束while循环 2#&9qGR  
boolean breakWhile = false;
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while(!bStop) kH*l83  
{ r:K)Q@  
write_nPos(); 3P Twpq1  
Utility.sleep(500); :xZ/c\  
breakWhile = true; R[ S*ON  
~!~VC)a*  
^ cN-   
for(int i=0;i<nStartPos.length;i++) nS[0g^}  
{ C-]H+p  
if(!fileSplitterFetch.bDownOver) udB:ys  
{
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breakWhile = false; K,tmh1  
break; !Jb?rSJ.h  
} g.f!Uc{  
} 94I8~Jj4  
if(breakWhile) TveCy&  
break; (xK=/()}q  
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//count++; k#`.!yI,  
//if(count>4) 3O%[k<S\VO  
// siteStop(); AQ. Y-'\t  
} C]*9:lK  
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System.err.println("文件下载结束！"); TJ7on
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} X;sl?8HG!<  
catch(Exception e){e.printStackTrace ();} #QZg{  
} ] =b?^'  
<;#d*&]  
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//获得文件长度 00?^!';  
public long getFileSize() 8gJ"7,}-'  
{ e`4Ol
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int nFileLength = -1; Lcplc"C  
try{ N<Rb<p
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URL url = new URL(siteInfoBean.getSSiteURL()); `kyr\+hp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2uS&A \  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9%oLv25{)  
]jG%<j9A  
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int responseCode=httpConnection.getResponseCode(); Y[$[0  
if(responseCode>=400) )HS|pS:  
{ Y%p"RB[  
processErrorCode(responseCode); "vH@b_>9|  
return -2; //-2 represent access is error PmvTCfsg  
} N_$ X4.7p  
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String sHeader; NeCTEe|V  
[[JwHM8H&  
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for(int i=1;;i++) @PU%BKe  
{ }PK8[N  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *'QD!Tc  
//Utility.log(in.readLine()); |B;:Ald  
sHeader=httpConnection.getHeaderFieldKey(i); g.s~Ph-G  
if(sHeader!=null) iU~oPp[e  
{ 0KHA5dt  
if(sHeader.equals("Content-Length")) DKF`uRvGN:  
{ 3O:Z;YP:<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); JyjS#BWi  
break; bv4lgRE6Y  
} Z81]>  
} UCa(3p^V_  
else R8W{[@  
break; =Mc*~[D/  
} 3(}W=oI  
} rMH\;\ I|U  
catch(IOException e){e.printStackTrace ();} aHXd1\6m  
catch(Exception e){e.printStackTrace ();} =CFO
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Utility.log(nFileLength); O< v0{z09*  
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return nFileLength; ^{DXin 1O`  
} w+fsw@dK&  
}Cvf[
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//保存下载信息（文件指针位置） ^{T]sv  
private void write_nPos()
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{ 0B>hVaj>-  
try{ r,cV(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `k+ci7;  
output.writeInt(nStartPos.length); k-Hy>5;  
for(int i=0;i<nStartPos.length;i++) etMQy6E\  
{ /vYuwaWG=  
// output.writeLong(nPos); jL8.*pfv  
output.writeLong(fileSplitterFetch.nStartPos); *?zmo
@-  
output.writeLong(fileSplitterFetch.nEndPos); )>QpR8 G-  
} D|9xD  
output.close(); |C301ENZ  
} 7y5`YJ}!  
catch(IOException e){e.printStackTrace ();} b}HLuX  
catch(Exception e){e.printStackTrace ();} @SjISZw_  
} tBd-?+~7  
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//读取保存的下载信息（文件指针位置） I<L  
private void read_nPos() *|{1`{8n  
{ 3q:U0&F  
try{ HL]8E}e\"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (HbA?Aja  
int nCount = input.readInt(); $REz{xgA=  
nStartPos = new long[nCount]; R&KFF'%  
nEndPos = new long[nCount]; o-a\T  
for(int i=0;i<nStartPos.length;i++) p{X?_F  
{ `k2YH?  
nStartPos = input.readLong(); /*Iq,"kGz  
nEndPos = input.readLong(); O$zXDxn  
} 6Ck 3tCr  
input.close(); 1[p6v4qO{  
} =hFIH\x  
catch(IOException e){e.printStackTrace ();} o1lhVM`15  
catch(Exception e){e.printStackTrace ();} H c,e&R  
} g]&7c:/  
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private void processErrorCode(int nErrorCode) *Tc lcu  
{ e_=TkG1E6  
System.err.println("Error Code : " + nErrorCode); StLFq6BO  
} O{^8dwg  
~H`m"4zQ  
^G(U@-0..  
//停止文件下载 =d`w~iC  
public void siteStop() MTXh-9DA  
{ ^E~F,]dV=  
bStop = true; rf?%- X(V  
for(int i=0;i<nStartPos.length;i++) T,@s.v  
fileSplitterFetch.splitterStop(); *I]/ [d  
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} sE^ee2]OI@  
} 7<GC{/^T  
//负责部分文件的抓取 sU Er?TZ  
**FileSplitterFetch.java IVSOSl|  
*/ C(CwsdlP  
package NetFox; UOIB}ut V  
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import java.io.*; J4?i\wD:  
import java.net.*; Ls<^z@I  
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public class FileSplitterFetch extends Thread { )iX2r{  
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String sURL; //File URL QjOO^6Fh  
long nStartPos; //File Snippet Start Position QL]e<2oPJ  
long nEndPos; //File Snippet End Position CiWz>HWH  
int nThreadID; //Thread's ID S^s|/!>  
boolean bDownOver = false; //Downing is over \uPyvA=  
boolean bStop = false; //Stop identical *Xcqnu('  
FileAccessI fileAccessI = null; //File Access interface W6gI#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8+i=u"<  
{ fHK.q({Qc  
this.sURL = sURL; &R5zt]4d&  
this.nStartPos = nStart; r
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this.nEndPos = nEnd; .Ht;xq  
nThreadID = id; }#r awVe=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {
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} 7F2 WmMS  
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public void run() : &bJMzB  
{ 2cEvsvw>  
while(nStartPos < nEndPos && !bStop) )x+P9|  
{ av&~A+b.r  
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try{ !\VzX  
URL url = new URL(sURL); C
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cgnMoBIc  
httpConnection.setRequestProperty("User-Agent","NetFox"); P!Brw72  
String sProperty = "bytes="+nStartPos+"-"; QLH!>9Ch  
httpConnection.setRequestProperty("RANGE",sProperty); en>n\;U  
Utility.log(sProperty); /WGD7\G'8  
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InputStream input = httpConnection.getInputStream(); 4a0Ud !Qcs  
//logResponseHead(httpConnection); Na$.VT  
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byte[] b = new byte[1024]; B(WmJ6e  
int nRead; |a#=o}R_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (gnN</%  
{
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nStartPos += fileAccessI.write(b,0,nRead); ^k*%`iQ  
//if(nThreadID == 1) 3?K+wg s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A!,c@Kv 3  
} ;*'I&  
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Utility.log("Thread " + nThreadID + " is over!"); [[HCP8Wk  
bDownOver = true; fF(AvMsO  
//nPos = fileAccessI.write (b,0,nRead); ep~+]7\  
} @<3E`j'p  
catch(Exception e){e.printStackTrace ();} X~UL$S;  
} aGBd~y@e  
} BYu(a  
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//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) :-O$rm  
{ KTt+}-vP^  
for(int i=1;;i++) :1Nc6G  
{ ZBR^$?nj  
String header=con.getHeaderFieldKey(i); k>F!S`a&m  
if(header!=null) qSlo)aP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |||m5(`S  
Utility.log(header+" : "+con.getHeaderField(header)); ZJW8S  
else T*mR9 8i  
break; iZ>P>x\  
} jI'?7@32`  
} 4lR+nmAZ  
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public void splitterStop()
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{ *^Zt)U1$|  
bStop = true; 1) K<x  
} xI<B)6D;f  
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} ~Er0$+q=Y;  
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/* WY QVe_<z:  
**FileAccess.java p>kny?AJ  
*//文件访问(定位，写) zRmVV}b  
package NetFox; %]Nm'"Y`U  
import java.io.*; ;hODzfNkS  
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public class FileAccessI implements Serializable{ 0[fBP\H"Wr  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4YI6&  
RandomAccessFile oSavedFile;  AV|:v3  
long nPos; KPDJ$,
:  
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public FileAccessI() throws IOException x^_c4,i)  
{ = 03G~7B>  
this("",0); h5T~dGRlR  
} h8%QF'C  

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public FileAccessI(String sName,long nPos) throws IOException RTvOaZ  
{ (e~9T MY  
oSavedFile = new RandomAccessFile(sName,"rw"); |OAiHSW"V  
this.nPos = nPos; BMQ4i&kF|  
oSavedFile.seek(nPos); J=8Y D"1  
} z>0$SBQ-  
cZ !$XXA`  
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public synchronized int write(byte[] b,int nStart,int nLen) qhG2j;  
{ **z^aH?B2  
int n = -1; ~`Vo0Z*S  
try{ pzjNi=vhd  
oSavedFile.write(b,nStart,nLen); 8kSyT'kC%  
n = nLen; ]8OmYU%6V  
} x!W5'DO  
catch(IOException e) /&G|.Cx  
{ ltU{P|7!E  
e.printStackTrace (); P.Cn[64a+@  
} 6C"zBJcGc  
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return n; |H,WFw1%}  
} 3TeRZ=2:*x  
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} [-"ZuUG  
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/* A /c  
**SiteInfoBean.java /E{tNd^S  
*/ -Vb5d!(  
package NetFox;  q^6#.}  
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public class SiteInfoBean { = =Q*|L-g  
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private String sSiteURL; //Site's URL 1#;^Z3  
private String sFilePath; //Saved File's Path ?G7*^y&Q  
private String sFileName; //Saved File's Name @c"s6h&  
private int nSplitter; //Count of Splited Downloading File c;(Fz^&_  
5kWzD'!^  
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public SiteInfoBean() DnhbMxh8o  
{//nSplitter的缺省值为5 90Sras>F  
//default value of nSplitter is 5 b{ A/M#=  
this("","","",5); -$#2?/uqC  
} 4
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B<Cg_C  
{ ;o;ak.dTt  
sSiteURL= sURL; [euR<i*I#  
sFilePath = sPath; qe?Ns+j<d  
sFileName = sName; g2^{+,/^K  
this.nSplitter = nSpiltter; v@2@9/  
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} &;r'
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^ T`T?*h  
i
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public String getSSiteURL() bUM4^m  
{ 5A5t
 
return sSiteURL;  @e\ @EW  
} _\,lv \u  
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public void setSSiteURL(String value) i|,}y`C#  
{ H"Hl~~U  
sSiteURL = value; l=Jw6F+5  
} pV\>?  
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.!lLj1?p  
public String getSFilePath() ,!,M'<?"  
{ =oiz@Q@H  
return sFilePath; y0?HZ Xq  
} r58<A'#  
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public void setSFilePath(String value) 9AQ,@xP|  
{ `m#G'E I  
sFilePath = value; L})*ck
 
} x;} 25A|  
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0
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public String getSFileName() nra)t|m  
{ -k2|`t _  
return sFileName; ?|}qT05  
} 7)2Q  
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public void setSFileName(String value) ]BRwJ2< x  
{ BNb_i H  
sFileName = value; ;.=0""-IF  
} jA~omX2A  
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public int getNSplitter() h -091N  
{ L*4=b (3  
return nSplitter; pEN`6*  
} t,0}}9%?  
\h0+` ;Q  
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public void setNSplitter(int nCount) {-]K!tWda  
{ <HS{A$]  
nSplitter = nCount; dNqj|Vu  
} `C-8zA  
} 55] MRv  
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ux6)K= ]  
/* +<V$G/"  
**Utility.java x5;D'Y t"|  
*/ @7Ln1v  
package NetFox; )S`Yl;oL  
Q.V@Sawe5  
(6[/7e)  
public class Utility { UMFM.GI  
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public Utility() 2lN0Sf@  
{ Pd `
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~-%z:Re'_  
} I)r6*|mz  
oz|+{b}%  
//线程睡眠
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public static void sleep(int nSecond) <1x u&Z7  
{ E6T=lwOZ  
try{ _pvt,pW  
Thread.sleep(nSecond); #\_FSr fX  
} YbZ?["S&  
catch(Exception e) **1=|aa:  
{ LUpkO  
e.printStackTrace (); 5UK}AkEe&x  
} {S@, ,  
} t
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//日志 {`>pigo  
public static void log(String sMsg) (5hUoDr!  
{ 5;XU6Rz!  
System.err.println(sMsg); {aopGu?i  
} ~0Zy$L/D  
tm_\(  
J~ *>pp#U  
public static void log(int sMsg)  7(o:J  
{ 8`I,KkWg   
System.err.println(sMsg); %_>8.7  
} M3JV^{O/DV  
} !9V; 8g  
Ca/N'|}^  
tTt}=hQpgX  
/* j~9![s!  
**TestMethod.java d5=&:cF  
*/ ^ZBTd5t#  
package NetFox; H>-{.E
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public class TestMethod { 6J-=6t|  
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5+(Cp3
  
public TestMethod() UMPW<>z  
{ ///xx/weblogic60b2_win.exe DW)81*~g  
try{ f]Rh<N$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <J}JYT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /f=31<+MtF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); scE#&OWF%  
fileFetch.start(); 8>I4e5Ym  
} cCG!X%9  
catch(Exception e){e.printStackTrace ();} N{a=CaYi+  
_]0<G8|Rv  
|2jA4C2L}  
} |NWHZo  
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public static void main(String[] args) ;2gO(  
{ "|E'E"_1  
new TestMethod(); CX]L'  
} ]#'&x%m  
} Fc^!="
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