http断点续传简单实现（java)

/* hH9~.4+*`g  
**SiteFileFetch.java aZ|?i }  
*/ 8f<y~L_(`  
package NetFox; t 9t '9  
import java.io.*; #1C]ZV] B  
import java.net.*; eIEL';N6  
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,>01Cs=t8  
public class SiteFileFetch extends Thread { +?
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SiteInfoBean siteInfoBean = null; //文件信息Bean D^2lb"3  
long[] nStartPos; //开始位置 5HsF#  
long[] nEndPos; //结束位置 L+VQtp&"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?E_;[(Mcr  
long nFileLength; //文件长度 nbB*d@"  
boolean bFirst = true; //是否第一次取文件 , O/IY  
boolean bStop = false; //停止标志 :5['V#(o  
File tmpFile; //文件下载的临时信息 u;]xAr1  
DataOutputStream output; //输出到文件的输出流 `a:3S@n(}  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;Xa N  
public SiteFileFetch(SiteInfoBean bean) throws IOException AAs&P+;  
{ ByuBZ!m  
siteInfoBean = bean; &XdTY +  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Q-!gO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hkyO_ns  
if(tmpFile.exists ()) 9J~\.:jH-  
{ j:qexhtho  
bFirst = false; ^%!SKhRIK  
read_nPos(); ";7xE#jRk  
} [=BMvP5  
else WF-jy7+  
{ p!8phS#iP  
nStartPos = new long[bean.getNSplitter()]; Xt
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nEndPos = new long[bean.getNSplitter()]; +Z2XP76(4A  
} x;sc?5_`  

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}  BdiV  
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public void run() ?pfr^ !@$  
{ _9t1aP5  
//获得文件长度 XXhN;-p  
//分割文件
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//实例FileSplitterFetch _'ebXrbZB  
//启动FileSplitterFetch线程 #AB5}rPEI  
//等待子线程返回 oPF]]Imu  
try{ 5y 5Dn!`  
if(bFirst) $|@vmv0  
{ m(?{#aaq  
nFileLength = getFileSize(); b- e  
if(nFileLength == -1) W1M322]>L  
{
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System.err.println("File Length is not known!"); $i6z)]rjg  
} G'p322Bu  
else if(nFileLength == -2) ~@Q]@8Tv\  
{ |dbKK\ X9  
System.err.println("File is not access!"); tK .1 *  
} 8Z_ 4%vUBg  
else <K<#)mcv  
{ +-(,'slov  
for(int i=0;i<nStartPos.length;i++) JKfJ%yy |  
{ !H)-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); rm9>gKN;#  
} q^sZP\i,*;  
for(int i=0;i<nEndPos.length-1;i++) 4oH ,_sr  
{ :{ZwzJ  
nEndPos = nStartPos[i+1]; ypG*41  
} 1AN$s  
nEndPos[nEndPos.length-1] = nFileLength; ppNMXbXR  
} NN=^4Xpc:  
} 23i2y
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//启动子线程 __Ksn^I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "O0xh_Nr  
for(int i=0;i<nStartPos.length;i++) 8{/.1:  
{ D>7J[ Yxg-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J{prI;]K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (YYg-@IO  
nStartPos,nEndPos,i);
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;Su-Y!&%  
fileSplitterFetch.start(); W[*xr{0V  
} H\a"=&M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;5.&TQT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xlJWCA*>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M /v@C*c  
nEndPos = " + nFileLength); H!Q72tyo  
// fileSplitterFetch[nPos.length-1].start(); d?J&mLQ6  
;>jEeIlT  
o h\$u5  
//等待子线程结束 %+Ze$c}X  
//int count = 0; Iq4B%xo6G  
//是否结束while循环 bTrusSAl  
boolean breakWhile = false; <7F-WR/2n  
|k90
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-5 PVWL\  
while(!bStop) rvy%8%e?  
{ ^7gKs2M  
write_nPos(); cPuXye  
Utility.sleep(500); vVw@^7U  
breakWhile = true; sAqy(oy#M  
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for(int i=0;i<nStartPos.length;i++) K&`1{,  
{ l#1#3F  
if(!fileSplitterFetch.bDownOver)
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{ ?..BA&zRk  
breakWhile = false; o}114X4q;  
break; Z;81"
  
} 'xj5R=V  
} l7qW)<r  
if(breakWhile) MkoK(m{7  
break; r>peKo[X(  
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CAC4A
  
//count++; 3MNM<Ih  
//if(count>4) "W%YsN0  
// siteStop(); X1`3KqK<9  
} gh?[x.U  
./k7""4  
.cQO?UKK  
System.err.println("文件下载结束！"); s$hO/INr  
} v{ >3)$1  
catch(Exception e){e.printStackTrace ();} n]' r3  
}  XyE$0i~t  
^ZQMRNP{r  
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//获得文件长度 rx2'].  
public long getFileSize() |_TI/i>?'  
{ px K&aY8  
int nFileLength = -1; "nu]3zcd  
try{ sb{K%xi%  
URL url = new URL(siteInfoBean.getSSiteURL()); zG6l8%q'UE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !9_(y~g{N  
httpConnection.setRequestProperty("User-Agent","NetFox"); ftxL-7y%  
4-x<^ ev=  
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int responseCode=httpConnection.getResponseCode(); A5yVxSF  
if(responseCode>=400) U_5`  
{ %5gdLm!p  
processErrorCode(responseCode); /Rq\Mgb  
return -2; //-2 represent access is error >pfeP"[(3  
} J@I>m N1\  
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:IS?si5|  
String sHeader; p lnH  
+mVAmG@  
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for(int i=1;;i++) l5Bm.H_  
{ PO"lY'W.U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'l.tV7  
//Utility.log(in.readLine()); )dhR&@r*w  
sHeader=httpConnection.getHeaderFieldKey(i); w!20  
if(sHeader!=null) 49QsT5b)  
{ F*PhV|XU  
if(sHeader.equals("Content-Length")) *{w0=J[15  
{ M<w
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K/ On|C  
break; !\7`I}:  
} xyGwYv>*KO  
} 34u[#O{2  
else cr!W5+r  
break; Jh EC  
} iX+8!>Q  
} JKM(fX+  
catch(IOException e){e.printStackTrace ();} +ausm!~6  
catch(Exception e){e.printStackTrace ();} I </P_:4G  
f $Agcy  
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Utility.log(nFileLength); xO )c23Z)]  
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return nFileLength; 5Z!$?J4Rl  
} nd8<*ru$  
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//保存下载信息（文件指针位置） A{zqr^/h  
private void write_nPos() N3L$"g5^  
{ NlEyT9  
try{ ~{Iw[,MJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZR}v_]l^  
output.writeInt(nStartPos.length); eA!Z7 '  
for(int i=0;i<nStartPos.length;i++) .A< HM}   
{ Og7yT{h_  
// output.writeLong(nPos); AhF@  
output.writeLong(fileSplitterFetch.nStartPos); <J;O$S  
output.writeLong(fileSplitterFetch.nEndPos); 3$!QP N  
} #Zm`*s`  
output.close(); PK:Lv15"r  
} TRi#  
catch(IOException e){e.printStackTrace ();} FTZ=u0  
catch(Exception e){e.printStackTrace ();} );.$`0  
} =Q_1Mr4O  
CqnHh@]nu  
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//读取保存的下载信息（文件指针位置） L}*o8l`  
private void read_nPos() 71nZi`AR  
{ D",L.  
try{ ]2@(^x'=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >`x|E-X"  
int nCount = input.readInt(); qIZ+%ZOu  
nStartPos = new long[nCount]; pWRdI_  
nEndPos = new long[nCount]; 0vqH-)}  
for(int i=0;i<nStartPos.length;i++) y$R8J:5f  
{ 9A.NM+u7  
nStartPos = input.readLong(); |D)CAQn,  
nEndPos = input.readLong(); mKe6rEUs|  
} =T[P  
input.close(); daKZ*B|  
} gtuSJ+up  
catch(IOException e){e.printStackTrace ();} n{4iW_/D  
catch(Exception e){e.printStackTrace ();} [}4zqY{  
} #g6_)B=S  
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private void processErrorCode(int nErrorCode) Dr.eos4 ~  
{ ; pBLmm*F  
System.err.println("Error Code : " + nErrorCode); u;t<rEC2  
} 1Gr^,Ry  
lu{ *]
!  
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//停止文件下载 ~%*l>GkP*  
public void siteStop() U%@
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{ ">Qxb.Y}  
bStop = true; PL=v,NB  
for(int i=0;i<nStartPos.length;i++) vb~%u;zrC@  
fileSplitterFetch.splitterStop(); \ZcI{t'a  
>k"O3Pc@  
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} O<s7VHj  
} .\a+m
 
//负责部分文件的抓取
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**FileSplitterFetch.java 55O}SUs!P  
*/ VjWJx^ZL#  
package NetFox; i<Ms2^  
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import java.io.*; wetu.aMp  
import java.net.*; !b`fykC  
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public class FileSplitterFetch extends Thread { = cxO@Fu  
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String sURL; //File URL F4\:9ws  
long nStartPos; //File Snippet Start Position R WY>`.su  
long nEndPos; //File Snippet End Position Bdh*[S\u@E  
int nThreadID; //Thread's ID -4QZ/*  
boolean bDownOver = false; //Downing is over LkJq Bg  
boolean bStop = false; //Stop identical 85# 3|5n  
FileAccessI fileAccessI = null; //File Access interface -`q!mdA2  
LBG`DYR@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &;ddnxFI  
{ zKP[]S-  
this.sURL = sURL; ]CP5s5  
this.nStartPos = nStart; A/=cGE  
this.nEndPos = nEnd; "#wAGlH6>  
nThreadID = id; -aJ(-Np$f  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 49E| f ^q  
} {@KLN<  
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public void run() *P *.'XM  
{ ~W>{Dd(J_  
while(nStartPos < nEndPos && !bStop) ~*EipxhstJ  
{ a)2l9  
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try{ @GAj%MK$  
URL url = new URL(sURL); ;L87 %P(.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5L6.7}B  
httpConnection.setRequestProperty("User-Agent","NetFox"); $!G|+OuTR  
String sProperty = "bytes="+nStartPos+"-"; umPnw  
httpConnection.setRequestProperty("RANGE",sProperty); !"phz&E5ah  
Utility.log(sProperty); 4Ty?>'*|  
xy>$^/[$  
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InputStream input = httpConnection.getInputStream(); \|X 1  
//logResponseHead(httpConnection); [x>Pf1  
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byte[] b = new byte[1024]; wa[J\lW  
int nRead; N/-(~r[
  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) CPa+?__B  
{ gm]q<~eMW  
nStartPos += fileAccessI.write(b,0,nRead); ?z)
2\D  
//if(nThreadID == 1) \Yp"D7:Qi  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R5MN;xG^  
} Usht\<{  
o$bQ-_B`  
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Utility.log("Thread " + nThreadID + " is over!"); ZD50-w;  
bDownOver = true; 0F!Uai1  
//nPos = fileAccessI.write (b,0,nRead); =WC
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} z1RHdu0;z  
catch(Exception e){e.printStackTrace ();} )e[q%%ks  
} Wsd_RT}ww  
} ,f>^q"  
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9&
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//打印回应的头信息 :1'1
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public void logResponseHead(HttpURLConnection con) n>^9+Rx|i  
{ 78T;b7!-C  
for(int i=1;;i++) ]mJ9CP8P1c  
{ 5FJ%"5n&  
String header=con.getHeaderFieldKey(i); !pa7]cZ  
if(header!=null) .}R'(gN\6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); N<(rP1)`v  
Utility.log(header+" : "+con.getHeaderField(header)); ]%7m+-h@  
else Yo5ged]i  
break; N+R{&v7=F%  
} lh0G/8+C  
} t(,2x%{  
3Qv9=q|[b  
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public void splitterStop() ,9:v2=C_  
{ ctgH/SU  
bStop = true; t- //.  
} Zjc/GO  
$ ga,$G  
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} D_f:D^  
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M+=q"#&  
/* ' z^v
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**FileAccess.java ,=ju^_^sA  
*//文件访问(定位，写) Odt<WG  
package NetFox; kYS\TMt,C  
import java.io.*; u8~5e  
l9rN!Q|  
!vr A\d  
public class FileAccessI implements Serializable{ W70BRXe04D  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~8Ef`zL  
RandomAccessFile oSavedFile; @$ )C pg  
long nPos; i[U=-4 J  
p{V(! v|  
)A;jBfr  
public FileAccessI() throws IOException :OaGdL   
{ Zg])uM]\2i  
this("",0); 3v~}hV/RUy  
} )6he;+  
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9Xh<vh8&  
public FileAccessI(String sName,long nPos) throws IOException ,(yaWd6  
{ ]G~u8HPH!m  
oSavedFile = new RandomAccessFile(sName,"rw"); j1@PfKh  
this.nPos = nPos; toox`|  
oSavedFile.seek(nPos); Im`R2_(]  
} ~r]$(V n  
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public synchronized int write(byte[] b,int nStart,int nLen) :rmi8!o  
{ _ZuI x=!  
int n = -1; zy9W{{:P(1  
try{ =?B[oq  
oSavedFile.write(b,nStart,nLen); vinn|_s%  
n = nLen; L!W5H2Mc  
} 'Ya-;5Y]  
catch(IOException e) KU0;}GSNX}  
{ Pu
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e.printStackTrace (); cmLI!"RLe  
} apm,$Vvjy  
6;\Tps;A  
hcD.-(-;)  
return n; 6[1lK8o  
} 52Q~` t7F  
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} LTio^uH  
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qB=%8$J  
/* NEM
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**SiteInfoBean.java h6gtO$A|p=  
*/ ]FO)U  
package NetFox; xHwcP21  
A `=.F  
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public class SiteInfoBean { _k5-Wd5Ypw  
}D#[yE,=\  
q}7(w$&  
private String sSiteURL; //Site's URL fL R.2vJ  
private String sFilePath; //Saved File's Path U[l{cRT   
private String sFileName; //Saved File's Name o,y{fv:ki  
private int nSplitter; //Count of Splited Downloading File /\uW[
mt  
|Q~5TL>b  
6?jSe<4x  
public SiteInfoBean() W#[3a4%m  
{//nSplitter的缺省值为5 Q92hI"  
//default value of nSplitter is 5 )pt#Pu  
this("","","",5); 4}=Z+tDu>  
} T_?,?  
;!N_8{ 7r  
RjQdlr6*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r)t-_p37  
{ 'ZQR
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sSiteURL= sURL; QW"BGg~6c  
sFilePath = sPath; 0\^K\J,.  
sFileName = sName; ?9AtFT  
this.nSplitter = nSpiltter; ig,v6lqhM  
sr,8Qd0M  
h7W<$\P  
} B6a   
,
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public String getSSiteURL() <q#/z&F!  
{ ?f[U8S}  
return sSiteURL; nHi6$} I  
} Ej64^*  
*+'l|VaVq\  
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public void setSSiteURL(String value) 2(sq*!tX  
{ cn!Y7LVr  
sSiteURL = value; k7Z1Y!n7  
} q\6ZmKGnT  
Lv?e[GA  
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public String getSFilePath() |G]M"3^  
{ s;-%Dfn  
return sFilePath; \?.Tq24  
} /WKp\r(Hp  
~,.}@XlgT.  
VN9C@ ;'$  
public void setSFilePath(String value) /SZg34%  
{ 'xY@I`x  
sFilePath = value; s\dF7/b  
} t{)J#8:g  
CK+_T}+-  
gcfEJN4'  
public String getSFileName() (t)a u  
{ K2
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return sFileName; {n>W8sN<  
} p
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BWN[>H %S  
S7 Tem:/  
public void setSFileName(String value) 2r=A'  
{ v'zf*]9  
sFileName = value; 55T c  
} c,I|O' &k  
cU'^ Ja?%  
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public int getNSplitter()  $VCWc#  
{ $w$
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return nSplitter; 7EAkY`Op  
} [8QE}TFic  
pP6pn~}  
W=T}hA#`  
public void setNSplitter(int nCount) _:tisr
{  
{ \;G97o  
nSplitter = nCount; x p#+{}  
} "ujt:4p@  
} |F 18j9  
+wwK#ocw  
-]h3s >
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/* ;tF7GjEp  
**Utility.java fXHNm$"n  
*/ A[6$'IJ  
package NetFox; 3%W R  
"sf]I[a  
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public class Utility { {s=$.Kg  
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public Utility() Sgt@G=_o  
{ .{1MM8 Q  
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} Nz&J&\X)tD  
yU(k;A-  
//线程睡眠 YrR}55V,  
public static void sleep(int nSecond) Uv06f+P(  
{ >#RXYDd  
try{ =kspHP<k  
Thread.sleep(nSecond); =y/VrF.bV  
} Tl!}9/Q5E:  
catch(Exception e) sGCV um}  
{ WBA0! g98  
e.printStackTrace (); *zy0,{bl  
} dB`YvKr#  
} P==rY5+s`  
;,y9  
//日志 zA![c l>$  
public static void log(String sMsg) @])q
w_  
{  0FHX  
System.err.println(sMsg); ba3_55]  
} ;!k1LfN  
*p.P/w@1  
$siiG|)C1  
public static void log(int sMsg) B=/*8,u  
{ 8yH) 8:w  
System.err.println(sMsg); .s_wP  
} ~T')s-,l,:  
} 5s>$  
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3H%oTgWk  
/* > @ulvHL  
**TestMethod.java P(W7,GD,k  
*/ uE>2*u\  
package NetFox; xOjCF&W  
=J,aBp  
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public class TestMethod { $b#"Rv  
h!f7/)|[o  
j+n1k^jC  
public TestMethod() 7:1c5F~M  
{ ///xx/weblogic60b2_win.exe EY(@R2~#J  
try{ e/WR\B'1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <dzE5]%\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); C,w$)x5kls  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ztG_::QtG]  
fileFetch.start(); ?EeHeN_  
} n2R{$^JxO  
catch(Exception e){e.printStackTrace ();} }Y5Sf"~M  
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YXH9Q@Gn  
} <BQ4x.[  
6ZVJ2xs[%  
.3,s4\.kT  
public static void main(String[] args) JQ%`]=n(/  
{ iuq-M?1  
new TestMethod(); Z^AACKME  
} i`E
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} }`yIO"{8n  
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