http断点续传简单实现（java)

/* 4$);x/ a  
**SiteFileFetch.java WUwH W  
*/ g ni=S~u  
package NetFox; "0Wi-52=V  
import java.io.*; ! z^%$;p  
import java.net.*; vdn`PS'#  
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public class SiteFileFetch extends Thread { FUVoKX!#  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #Sxk[[KwH*  
long[] nStartPos; //开始位置 cjf 8N:4N0  
long[] nEndPos; //结束位置 i'w8Li  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .^aakM  
long nFileLength; //文件长度 MM}lW-q;  
boolean bFirst = true; //是否第一次取文件 *&f^R}O  
boolean bStop = false; //停止标志 t<)Cbple\  
File tmpFile; //文件下载的临时信息 L\cd=&b`  
DataOutputStream output; //输出到文件的输出流 T
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） '
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public SiteFileFetch(SiteInfoBean bean) throws IOException 81gcM
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{ O_zW/#  
siteInfoBean = bean; LW={| 3}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); P=.yXirm?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); mv5=>Xc6  
if(tmpFile.exists ()) +VJS/  
{ ! :[`>=!  
bFirst = false; :bh#,]'  
read_nPos(); J**-q(>  
} ;_o1{?~  
else @%(Vi!Cv"R  
{ SdOa
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nStartPos = new long[bean.getNSplitter()]; )\ `AD#  
nEndPos = new long[bean.getNSplitter()]; zTgY=fuz  
} j20/Q)=h  
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} |WiE`&?xP  
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public void run() 1JRM@!x  
{ 1V\tKDM  
//获得文件长度 )\S3Q  
//分割文件 o!]muO*Rm  
//实例FileSplitterFetch QKW\z aG  
//启动FileSplitterFetch线程 5r&bk`  
//等待子线程返回 bW]7$?acv  
try{ HE;}B!>  
if(bFirst) iyA=d{S;V  
{ ~XzT~WxW  
nFileLength = getFileSize(); L}~"R/iWCT  
if(nFileLength == -1) $?_/`S13  
{ rr@h9bak;g  
System.err.println("File Length is not known!"); @U8}K#  
} M id v  
else if(nFileLength == -2) jR1o<]
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{ J0ysZ]  
System.err.println("File is not access!"); q,i&%  
} b< dwf[  
else ',WnT:  
{ "QKCZ8_C  
for(int i=0;i<nStartPos.length;i++) og`rsl  
{ &$$o=Yg,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); GI se|[p  
} AiP#wK;  
for(int i=0;i<nEndPos.length-1;i++) ]u]BxMs  
{ t5| }0ID-  
nEndPos = nStartPos[i+1]; S/itK3  
} - w{`/  
nEndPos[nEndPos.length-1] = nFileLength; y*G3dWb  
} UmR\2 cs  
} `rLcJcW  
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//启动子线程 1fK]A*{p  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 43VBx<"  
for(int i=0;i<nStartPos.length;i++) NJNS8\4  
{ @A5'vf|2;.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AV>_bw.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ){nOM$W  
nStartPos,nEndPos,i); ^xyU*A}D  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); afw`Heaa2(  
fileSplitterFetch.start(); `WUyffS/!  
} &<=?O a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wit rC>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); HBdZE7.x)3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", CN{xh=2qY[  
nEndPos = " + nFileLength); d-sT+4o}  
// fileSplitterFetch[nPos.length-1].start(); Q$yMU[l)  
1dhuLN%Ce  
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//等待子线程结束 _qxBjB4t"a  
//int count = 0; 2q NA\-0i>  
//是否结束while循环 [.(,vn?6  
boolean breakWhile = false; 33=lR-N#  
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while(!bStop) k-Z:z?M  
{ :MP*Xy\7&J  
write_nPos(); w+wg)$i  
Utility.sleep(500); b9xvLR8  
breakWhile = true; l(y,lK=YP1  
)ZW[$:wA  
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for(int i=0;i<nStartPos.length;i++) 9Q.@RO$%C  
{ )n&6= Li  
if(!fileSplitterFetch.bDownOver) M!/!*,~  
{ g5C$#<28  
breakWhile = false; 5|jsv)M+  
break; cBD#F$K2  
} =h@t#-Z"  
} 7BS5Eq B=  
if(breakWhile) `53S[8  
break; :5X^t  
kaT !  
N>H#Ew@2U  
//count++; kz*6%Cg*~  
//if(count>4) f<{f/lU@  
// siteStop(); 2oF1do;  
}
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System.err.println("文件下载结束！"); `-!kqJ  
} I7#^'/  
catch(Exception e){e.printStackTrace ();} 3xz|d`A  
} *EwDwS$$  
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//获得文件长度 zIA)se Js  
public long getFileSize() 9/`3=r@  
{ *iN5/w{VG  
int nFileLength = -1; &qzy?/i8  
try{ Y?qUO2  
URL url = new URL(siteInfoBean.getSSiteURL()); @#p6C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #tIeI6Qw  
httpConnection.setRequestProperty("User-Agent","NetFox"); D#D55X^6*  
#P1U]@  
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int responseCode=httpConnection.getResponseCode(); %L|xmx!c  
if(responseCode>=400) 6)PnzeYW  
{ vqAEF^HYry  
processErrorCode(responseCode); ;X N Ahg7  
return -2; //-2 represent access is error PfsUe,*  
} @6 a'p  
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String sHeader; )<f4F!?,A  
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for(int i=1;;i++) lNsdbyV'  
{ Qr_0 L  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e"%uOuIYX  
//Utility.log(in.readLine()); oj[~H}>  
sHeader=httpConnection.getHeaderFieldKey(i); =A*a9c2  
if(sHeader!=null) N^M6*,F,J  
{ 1%C EUE  
if(sHeader.equals("Content-Length")) 1cc~UQ  
{ id9XwWV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Na4O( d`  
break; }H<Z`3_U%  
} '1rGsfp6In  
} E4
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else (< >Lfn  
break; jz~#K;3=,  
} ORM3o
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} ~"_!O+Pj  
catch(IOException e){e.printStackTrace ();} #].qjOj  
catch(Exception e){e.printStackTrace ();} .^2.h  
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Utility.log(nFileLength); %{7*o5`
 
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return nFileLength; 3 l}9'j  
} ~;z] _`_Va  
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2$MoKOx8$  
//保存下载信息（文件指针位置） bIlNA)g  
private void write_nPos() vcCNxIzEG  
{ B9Mp3[  
try{ d>NO}MR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); d&AO4^  
output.writeInt(nStartPos.length); sv&^sARN  
for(int i=0;i<nStartPos.length;i++) y@,PTF  
{ q7rb3d  
// output.writeLong(nPos); Td|u-9OM  
output.writeLong(fileSplitterFetch.nStartPos); Cn{v\Q~.4
 
output.writeLong(fileSplitterFetch.nEndPos); ?0M$p  
} }30Sb&"  
output.close(); +0)M1!gK  
} 9Zj3"v+b  
catch(IOException e){e.printStackTrace ();} |h%HUau  
catch(Exception e){e.printStackTrace ();} eXD~L&s[  
}
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//读取保存的下载信息（文件指针位置） :
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private void read_nPos() @/?i|!6  
{
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try{ B'Jf&v  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4:S]n19nq  
int nCount = input.readInt(); &ds+9A  
nStartPos = new long[nCount]; 2S~(P  
nEndPos = new long[nCount]; `d^Q!QxE  
for(int i=0;i<nStartPos.length;i++) |5%T)  
{ !H@HgJ -  
nStartPos = input.readLong(); =+UtAf<n  
nEndPos = input.readLong(); `"}).{N]C  
} /t`,7y3T  
input.close(); sp:4b$zX  
} k\qFWFR  
catch(IOException e){e.printStackTrace ();} 6Q\|8a  
catch(Exception e){e.printStackTrace ();} F\&{>&  
} MUsF  
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private void processErrorCode(int nErrorCode) Woj5 yr  
{ [|YvVA  
System.err.println("Error Code : " + nErrorCode); SD:D8"8  
}
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//停止文件下载 zwU[!i)  
public void siteStop() W7'<Jom|?  
{ ']>9/r#  
bStop = true; 8B &EH+  
for(int i=0;i<nStartPos.length;i++) 99`w'Nlk  
fileSplitterFetch.splitterStop(); [U",yN]d  
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} J _dgP[  
} {J izCUo_'  
//负责部分文件的抓取 {|hg3R~A  
**FileSplitterFetch.java ~##FW|N)  
*/ h@NC#Iod  
package NetFox; |h
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import java.io.*; GC7WRA  
import java.net.*; qzJ<9H  
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public class FileSplitterFetch extends Thread { zG<<MR/<  
V4NQcy? H  
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String sURL; //File URL ohqThl  
long nStartPos; //File Snippet Start Position $l"%o9ICG  
long nEndPos; //File Snippet End Position =?0v,;F9|  
int nThreadID; //Thread's ID !L9OJ1F  
boolean bDownOver = false; //Downing is over R'`'q1=R  
boolean bStop = false; //Stop identical {pH#zs4Y  
FileAccessI fileAccessI = null; //File Access interface qe#5;
#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ZSK_Lux>  
{ RG'76?z  
this.sURL = sURL; (m,H
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this.nStartPos = nStart; [ 5}Q  
this.nEndPos = nEnd; Nj3iZD|  
nThreadID = id; u%e~a]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Pb>/b\&JS  
} YLQ0UeDN'  
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public void run() .!KsF h,pK  
{ KzO"$+M  
while(nStartPos < nEndPos && !bStop) YwET.(oo  
{ Uzzm2OS`  
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try{ F/BR#J1  
URL url = new URL(sURL); {CI4AT!?W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $'3
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httpConnection.setRequestProperty("User-Agent","NetFox"); u-,}ug|  
String sProperty = "bytes="+nStartPos+"-"; lTqlQ<`V  
httpConnection.setRequestProperty("RANGE",sProperty); D)ri_w!Q  
Utility.log(sProperty); U< Xdhgo?
 
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InputStream input = httpConnection.getInputStream(); ]/1\.<uJId  
//logResponseHead(httpConnection); .>F4s_6l  
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byte[] b = new byte[1024]; 3._
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int nRead; s2G9}i{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) N$]er'`  
{ LZe)_9$  
nStartPos += fileAccessI.write(b,0,nRead); Na/Y1RW  
//if(nThreadID == 1) sd\p[MXX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q/U-6A[0  
} $xZ ~bE9  
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Utility.log("Thread " + nThreadID + " is over!"); ? /z[Jx.  
bDownOver = true; vHpw?
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//nPos = fileAccessI.write (b,0,nRead); (?\+
  
} `T[@-  
catch(Exception e){e.printStackTrace ();} i>YQ<A1  
} K#wA ;  
} R>"Fc/{y  
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//打印回应的头信息 (8h4\utA  
public void logResponseHead(HttpURLConnection con) c]ARgrH-  
{ g) u%?T  
for(int i=1;;i++) Vz/w.%_g  
{ _=s9o/Cn]  
String header=con.getHeaderFieldKey(i); -Y/i h(I^  
if(header!=null) O+=%Mz(l  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]q%r2 (y,k  
Utility.log(header+" : "+con.getHeaderField(header)); U*$P"sS`  
else xrg?{*\  
break; Y)X7*iTi'j  
} E@ U]k$M  
} B{j><uxl  
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EYq?NL='  
public void splitterStop() [UzD3VPg  
{ <@-O06  
bStop = true; 8O,\8:I#  
} Yao}Xo9}  
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} 4$&l`yWU+  
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/* Kk8}m;  
**FileAccess.java ~U&NY7.@  
*//文件访问(定位，写) AYA{_^#+3  
package NetFox; ,D+ydr  
import java.io.*; !lgL=Ys(  
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SU~a()"  
public class FileAccessI implements Serializable{ }~I!'J#)  
 lln"c  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z5fE<=<X_W  
RandomAccessFile oSavedFile; njy2pDC@  
long nPos; :jl*Y-mM  
C:J;'[,S  
fkzSX8a9}  
public FileAccessI() throws IOException 2H|:/y  
{ /e'3\,2_  
this("",0); .c"nDCFVR  
} ^}=)jLS  
y d97ys  
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public FileAccessI(String sName,long nPos) throws IOException 2nB99L{6  
{ e,p"=/!aY  
oSavedFile = new RandomAccessFile(sName,"rw"); ^&
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this.nPos = nPos; ,@ 8+%KqG  
oSavedFile.seek(nPos); SN{+ Pk  
} iNA3Y  
+NPL.b|  
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public synchronized int write(byte[] b,int nStart,int nLen) V*4Z.3/E5  
{ &F&`y  
int n = -1; Ht Fr(g\"$  
try{ uDDa>Ka#+  
oSavedFile.write(b,nStart,nLen); te+}j7SU  
n = nLen; x4
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} 7s|'NTp  
catch(IOException e) I@'[>t  
{ g<:Lcg"u  
e.printStackTrace (); JY0aE  
} >H;i#!9,  
")|/\ w,  
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return n; h&<"jCjL
 
} $xbC^ k  
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} NfgXOLthM  
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/* ob.<j  
**SiteInfoBean.java Bs~~C8+  
*/ n1f8jS+'}  
package NetFox; ]" 'yf;g  
o^"+X7)  
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public class SiteInfoBean { -N45ni87  
}@r23g%  
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private String sSiteURL; //Site's URL E`IXBI  
private String sFilePath; //Saved File's Path Vm[Rp,"  
private String sFileName; //Saved File's Name cbzA`b'Mg  
private int nSplitter; //Count of Splited Downloading File N"S`9B1eD(  
pi"H?EHk  
,-pE/3|(  
public SiteInfoBean() uBm"Xkxe|w  
{//nSplitter的缺省值为5 f@OH~4FG  
//default value of nSplitter is 5 o7) y~ ke  
this("","","",5); )(}[S:`  
} -H-U8/WC  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;sB=f  
{ Th)
  
sSiteURL= sURL; 5 D|#l*V  
sFilePath = sPath; DSrU7#  
sFileName = sName; *QC6zJ  
this.nSplitter = nSpiltter; 7~h3B<  
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\((iR>^|  
} *[Hp&6f  
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public String getSSiteURL() 02J/=AC5  
{ S,&LH-ps  
return sSiteURL; ;wv[';
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} )@g[aRFa  

&`^(dO9  
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public void setSSiteURL(String value) MP%#)O6  
{ 'n &p5%  
sSiteURL = value; ?WI v4
 
} m eF7[>!U  
*/aY$aWv  
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public String getSFilePath() V._-iw]v  
{ =M\yh,s!  
return sFilePath; bxXpw&  
} GkAd"<B  
0Wr<l%M)+  
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public void setSFilePath(String value) UTA|Ps$  
{ k[Em~>m  
sFilePath = value; H=/1d.p  
} ]iV]7g8:  
<5zR-UA>  
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public String getSFileName() `G\ qGllX  
{ N*IroT3  
return sFileName; ti5fsc  
} 49qa  
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8FsQLeOE  
public void setSFileName(String value) t[|oSF#i  
{ }z]d]  
sFileName = value; UF9={fN1  
} Ac_P^  
-laH^<jm5  
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public int getNSplitter() $(1t~u<17  
{ )~'UJPK  
return nSplitter; :5kDc" =Z|  
} !?,, ZD  
vl (``5{  
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public void setNSplitter(int nCount) Kw fd S(
 
{ }&v}S6T  
nSplitter = nCount; L$ T2 bul  
} ,EQ0""G!  
} rZUTBLZ`j  
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4 ]oe`yx  
/* x?i wtZ@  
**Utility.java %JeNDXbI4  
*/ !'$*Z(  
package NetFox; frcAXh9  
bJ2-lU% ;2  
>N^<Q4%2  
public class Utility { cW3'057  
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public Utility() igu1s}F  
{ {4+/0\  
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} g~<[;6&{  
-@AhJY.  
//线程睡眠 `^#Rwn#  
public static void sleep(int nSecond) o[;P@F  
{ ra~=i|s  
try{ 4"
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Thread.sleep(nSecond); Lg\3DzM  
} -^NW:L$|  
catch(Exception e) '6D"QDZB  
{ |q4=*Xq  
e.printStackTrace (); TOiLv.Dor  
} `0upm%A  
} C:1(<1K  
7(/yyZQnZ  
//日志 l>*X+TpA,  
public static void log(String sMsg) $_JfM^w  
{ w5Fk#zJv  
System.err.println(sMsg); jTwSyW  
} +[}y` -t  
:[a*I6/^  
-w+.'  
public static void log(int sMsg) ]Zb9F[  
{ IB|!51H  
System.err.println(sMsg); c:Cz
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} 9@1n:X  
} lLQcyi0  
-3(*4)h7  
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/* wQW`Er3w  
**TestMethod.java Jk{SlH3'  
*/ %lbvK^  
package NetFox; pg5W`
4-F  

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public class TestMethod { .XpuD,^;@  
\=({T_j4  
}^I3
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public TestMethod() @Mg&T
$  
{ ///xx/weblogic60b2_win.exe UR'v;V&Cb\  
try{ y ;mk]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (KO]>!t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -75mgOj.#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <Hv/1:k}  
fileFetch.start(); Jd `Qa+  
} U:x;4  
catch(Exception e){e.printStackTrace ();} NxJnU<g-  
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} S/Ic=  
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public static void main(String[] args) BZLIi O  
{ (e_<~+E  
new TestMethod(); 3'p1m`8  
} @|h9jx|  
} nh7_ jEX  
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