http断点续传简单实现（java)

/* wgGl[_)  
**SiteFileFetch.java }y gD3:vN7  
*/ vy:Z/1q  
package NetFox; &E5g3lf  
import java.io.*; t&e{_|i#+  
import java.net.*; }a(dyr`S  
<bEbweQrgm  
)|#sfHv7  
public class SiteFileFetch extends Thread { b,1ePS  
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SiteInfoBean siteInfoBean = null; //文件信息Bean bq0zxg%  
long[] nStartPos; //开始位置 UH"%N)[  
long[] nEndPos; //结束位置 Em~>9f ?Q(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }`m/bgtFX  
long nFileLength; //文件长度 Ao&"r[oJSv  
boolean bFirst = true; //是否第一次取文件 YNsJZnGr8#  
boolean bStop = false; //停止标志 oj+hQ+>  
File tmpFile; //文件下载的临时信息 LyFN.2q
w  
DataOutputStream output; //输出到文件的输出流 kc`Tdn  
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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 tf`^v6m%]  
{ ds[|   
siteInfoBean = bean; d
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); j*r{2f4Rt  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !'*-$e  
if(tmpFile.exists ()) c(s.5p ^  
{ xMG~N`r  
bFirst = false; T{[=oH+  
read_nPos(); WCixKYq  
} ]>Es4 s  
else <frutU16\  
{ ; kI134i=  
nStartPos = new long[bean.getNSplitter()]; ge8ZsaiU  
nEndPos = new long[bean.getNSplitter()]; amY!qg0P*  
} {&1/V  
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} JY(WK@  
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p H2Sbs:Tk  
public void run() v):Or'$~M  
{ ji0@P'^;  
//获得文件长度 Q*~]h;6\{d  
//分割文件 z!9-
:  
//实例FileSplitterFetch >e$PP8&i_T  
//启动FileSplitterFetch线程 TAW/zpps$  
//等待子线程返回 ]N F[>uiW  
try{ 7WZ+T"O{I  
if(bFirst) ePo}y])2  
{ {9q4)R}G  
nFileLength = getFileSize(); k~nBiV  
if(nFileLength == -1) k~w*W X'  
{ ]~3V}z,T*  
System.err.println("File Length is not known!"); -6B4sZpzD  
} rmg}N  
else if(nFileLength == -2) 7J<5f)  
{ QhJiB%M
 
System.err.println("File is not access!"); 8v%o,"  
} &^Q/,H~S  
else c\AfaK^KF  
{ ;u)I\3`*!  
for(int i=0;i<nStartPos.length;i++) 1bX<$>x9u  
{ SO0PF|{\r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;uP:"k  
} 20Wg=p9L  
for(int i=0;i<nEndPos.length-1;i++) sd|).;s}  
{ 1p=]hC  
nEndPos = nStartPos[i+1]; qY!Zt_Be6  
} HN|%9{VeB  
nEndPos[nEndPos.length-1] = nFileLength;
& >fQp(f  
} _.8S&  
} #AQV(;r7@  
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//启动子线程 h~zT ydnH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ig>(m49d  
for(int i=0;i<nStartPos.length;i++) Er?&Y,o  
{ %1+4_g9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (SAs-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Rnq7LG
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nStartPos,nEndPos,i); )+9Uoe~6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $~T4hv :  
fileSplitterFetch.start(); <wD-qTW  
} [/8%3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |&i<bqLw:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); },-H"Qs  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Pe3o;mx  
nEndPos = " + nFileLength); X=&KayD  
// fileSplitterFetch[nPos.length-1].start(); I%KYtv~`  
'6%2.[o  
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//等待子线程结束 K]w'&Qm8W  
//int count = 0; $ $
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//是否结束while循环 3%b6{ie/=  
boolean breakWhile = false; GnJt0{  
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}Jj}%XxKs  
while(!bStop) nAlQ7'  
{ +mT_QsLEv  
write_nPos(); |+D!= :x  
Utility.sleep(500); KoT%Mfu  
breakWhile = true; FfT

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for(int i=0;i<nStartPos.length;i++) am6L8N  
{ iDqoa\  
if(!fileSplitterFetch.bDownOver)  _6vWF  
{ dG?*y  
breakWhile = false; ]3Sp W{=^(  
break; q'Pf]
  
} 7;@]t^d=$  
} /Lr.e
%  
if(breakWhile) +9sQZB# (  
break; [j+sC*  
>Cq<@$I2EB  
mj7#&r,1l  
//count++; G$('-3@i`w  
//if(count>4) 1T n}
 
// siteStop(); ?(_08O  
} gL/9/b4  
`C'H.g\>2Q  
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System.err.println("文件下载结束！"); QS;f\'1bb  
} +]{G@pn  
catch(Exception e){e.printStackTrace ();} &s>Jb?_5Mx  
} S)"Jf?  
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{
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//获得文件长度 k)TpnH! "  
public long getFileSize() XfIJ4ZM5  
{ LCV(,lu  
int nFileLength = -1; Xne1gms  
try{ dft!lBN  
URL url = new URL(siteInfoBean.getSSiteURL()); BDQsP$'6QT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /Z}}(6T  
httpConnection.setRequestProperty("User-Agent","NetFox"); +D*Z_Yh6  
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int responseCode=httpConnection.getResponseCode(); ,zY{  
if(responseCode>=400) xxQ;xI0+]  
{ -jmY)(\  
processErrorCode(responseCode); zX i'kB  
return -2; //-2 represent access is error A?OQE9'  
} &_8947  
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String sHeader; ~v6D#@%A  
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for(int i=1;;i++) lq7E4r  
{ b" [|:F>P  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #fM`}Ij.A  
//Utility.log(in.readLine()); P16~Qj  
sHeader=httpConnection.getHeaderFieldKey(i); VuZr:-K/  
if(sHeader!=null) %E;'ln4h&,  
{ _7y[B&g[r  
if(sHeader.equals("Content-Length")) buHJB*?9  
{ Q22 GIr  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +&H4m=D-#a  
break; E' uZA  
} ;}p  
} +jgS
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else hOK8(U0  
break; n~Lt\K:  
} )D%~`,#pQ  
} WUTowr  
catch(IOException e){e.printStackTrace ();} :
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catch(Exception e){e.printStackTrace ();} u9p$YJ  
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Utility.log(nFileLength); >=w)x,0yX  
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return nFileLength; bW+:C5'  
} "d}Gp9+$VY  
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&BSn?  
//保存下载信息（文件指针位置） iH'p>s5L  
private void write_nPos() l;E(I_ i)  
{ w&.aQGR#  
try{ Gav$HLx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); h;'~,xA  
output.writeInt(nStartPos.length); 0b 54fD=  
for(int i=0;i<nStartPos.length;i++) #T"4RrR  
{ :Llb< MY2  
// output.writeLong(nPos); )QJUUn#  
output.writeLong(fileSplitterFetch.nStartPos); (**oRwr%  
output.writeLong(fileSplitterFetch.nEndPos); |k9 C/  
} m(P]k'ZH?  
output.close(); -D:b*D  
} 1{.9uw"2S  
catch(IOException e){e.printStackTrace ();} X5w$4Kj&4l  
catch(Exception e){e.printStackTrace ();} :rP=t ,  
} asqV~n
 
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//读取保存的下载信息（文件指针位置） $<OD31T  
private void read_nPos() y>ktcuML  
{ eszG0Wu  
try{ 43 :X,\~)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1x
x}~|F?|  
int nCount = input.readInt(); 1B\WA8  
nStartPos = new long[nCount]; 0tJZ4(0  
nEndPos = new long[nCount]; tT._VK]o&R  
for(int i=0;i<nStartPos.length;i++) Ew$C ;&9  
{ *yGGBqd  
nStartPos = input.readLong(); 5`_SN74o  
nEndPos = input.readLong(); qcRs$-J  
} f?)-}\[IR{  
input.close(); @E8+C8'  
} >.D4co>  
catch(IOException e){e.printStackTrace ();} u]G\H!WkQ  
catch(Exception e){e.printStackTrace ();} H%{+QwzZ[j  
} A?0Nm{O;3v  
O33`+UV"W  
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private void processErrorCode(int nErrorCode) 0IWf!Sk ]  
{ Gp\ kU:}&  
System.err.println("Error Code : " + nErrorCode); 4{Z)8;QX  
} h>bx}$q  
(QiAisE  
O.JN ENZf  
//停止文件下载 UL9n-M=  
public void siteStop() ,]/X\t5]D  
{ bs1Rvx1:J%  
bStop = true; ;9'OOz|+1  
for(int i=0;i<nStartPos.length;i++) . 'yCw#f  
fileSplitterFetch.splitterStop(); $`'/+x"%  
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} #,v{Ihn  
} Z #m+ObHK1  
//负责部分文件的抓取 .o}v#W+st  
**FileSplitterFetch.java wS3'?PRX  
*/ .tr!(O],h  
package NetFox; H%lVl8oQ  
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import java.io.*; XB5DPx  
import java.net.*; \.}c9*)  
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public class FileSplitterFetch extends Thread { ]
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String sURL; //File URL k==h|\|  
long nStartPos; //File Snippet Start Position AwF:Iu^3n  
long nEndPos; //File Snippet End Position 8Cv?Z.x5  
int nThreadID; //Thread's ID h@wgd~X9  
boolean bDownOver = false; //Downing is over HkVB80hv  
boolean bStop = false; //Stop identical Jfl!#UAD|n  
FileAccessI fileAccessI = null; //File Access interface 7cMv/g^h@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3irl (;v  
{ '/%H3A#L  
this.sURL = sURL; H" 7u7l  
this.nStartPos = nStart; k~z Iy;AZ  
this.nEndPos = nEnd; g#E-pdY  
nThreadID = id; pI<f) r  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1m0c|ckb  
} Srd4))2/0  
is@?VklnB  
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public void run() E&:,oG2M  
{ I1&aM}y{G  
while(nStartPos < nEndPos && !bStop) MnW+25=N  
{ k$}fWR  
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try{ 8*a&Jl  
URL url = new URL(sURL); `~q<N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Yu2Bkq+  
httpConnection.setRequestProperty("User-Agent","NetFox"); L9#g)tf 8T  
String sProperty = "bytes="+nStartPos+"-"; jZrq{Z<  
httpConnection.setRequestProperty("RANGE",sProperty); #gw]'&{8D  
Utility.log(sProperty); /; 85i6  
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18:%~>.!  
InputStream input = httpConnection.getInputStream(); 0+b1vhQ  
//logResponseHead(httpConnection); #C@FYOf*  
,5<Cd,`*  
.(2
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byte[] b = new byte[1024]; 3"\lu?-E  
int nRead; Pj%|\kbNs  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  %D "I  
{ koi^l`B$  
nStartPos += fileAccessI.write(b,0,nRead); ^5 Tqy(M  
//if(nThreadID == 1) 63B?.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A&jlizN7  
} E8&TO~"a]e  
Ozf@6\/t  
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Utility.log("Thread " + nThreadID + " is over!"); m&yJzMW|  
bDownOver = true; +^T@sa`[I  
//nPos = fileAccessI.write (b,0,nRead); |$_sX9\`?|  
} @U
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catch(Exception e){e.printStackTrace ();} H} g{Cr"Ex  
} @D
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} ;sFF+^~L  
[j'X;tVX{  
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//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) u,4eCxYE$  
{ nzeX[*  
for(int i=1;;i++) JqiP>4Uwm^  
{ jo@J}`\Zt  
String header=con.getHeaderFieldKey(i); jW@
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if(header!=null) *-p}z@8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Mf``_=K  
Utility.log(header+" : "+con.getHeaderField(header)); uu687|P
m  
else <c/5b]No  
break; *~i ])4  
} /&94 eC  
} ,zY$8y
]  
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public void splitterStop() cYt!n5w~W  
{ pz>>)c`  
bStop = true; 4HA<P6L  
}
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} PwLZkr@4^  
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4{`{WI{  
/* U/NoP4~{  
**FileAccess.java ~qOa\#x_  
*//文件访问(定位，写) '`KY!
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package NetFox; XpJ7o=?W3  
import java.io.*; n?Nt6U  
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@<&m|qtMsz  
public class FileAccessI implements Serializable{
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '."ed%=MC  
RandomAccessFile oSavedFile; 
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long nPos; HA>OkA/  
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public FileAccessI() throws IOException y h9*z3  
{ )+2hl  
this("",0); Jg|XH L)  
} d-dEQKI?;  
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public FileAccessI(String sName,long nPos) throws IOException [HZv8HU|  
{ 0KOgw*>_  
oSavedFile = new RandomAccessFile(sName,"rw"); p=}Nn(  
this.nPos = nPos; 65Yv4pNL  
oSavedFile.seek(nPos); 9;-p'C  
} %8
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a!AA]  
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public synchronized int write(byte[] b,int nStart,int nLen) jtc]>]6i  
{ NHZz _a=  
int n = -1; 9mTJ|sN:e  
try{ hZ  
oSavedFile.write(b,nStart,nLen); ;MdlwQ$`  
n = nLen; :G%61x&=Zc  
} $ gS>FJ  
catch(IOException e) }Kbb4]t|"  
{ B,epzI  
e.printStackTrace (); v z '&%(  
} ;@|n @ax  
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return n; N5b!.B x-w  
} Ej8^Zg  
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v #j$;  
} &FN.:_E  
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/* (0_2sfS  
**SiteInfoBean.java YglmX"fLf  
*/ <B6H. P =  
package NetFox; Gu\q%'I  
!."D]
i;  
;@Y;g(bw:  
public class SiteInfoBean { 4u})+2W  
n8ZZ#}Nhg  
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private String sSiteURL; //Site's URL ExL0?FemWV  
private String sFilePath; //Saved File's Path L>4"(  
private String sFileName; //Saved File's Name i6Emhji  
private int nSplitter; //Count of Splited Downloading File \n|EM@=eE  
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IKilr'  
public SiteInfoBean() ^yN&ZI3P&  
{//nSplitter的缺省值为5 fHd#u%63K  
//default value of nSplitter is 5 l?n\i]
'  
this("","","",5); JO6)-U$7UG  
} |imM#wF  
hy"\RW  
}*pi<s  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?QdWrE_  
{ aQ\$A`?  
sSiteURL= sURL; 57  
sFilePath = sPath; [~c|mOk  
sFileName = sName; a'yK~;+_9  
this.nSplitter = nSpiltter; SbrecZ  
)W _v:?A9  
3K0A)W/YEs  
} OU $#5  
ud@%5d  
<&g,Nc'5C  
public String getSSiteURL() -ifFbT+x  
{ 4yA+h2  
return sSiteURL; 0rs"o-s<  
} N]=q|D  
8\A#CQ5b  
^KT Y?  
public void setSSiteURL(String value) qHlQ+:n  
{ .~~T\rmI  
sSiteURL = value; "CQa.%  
} =wV<hg)C  
m'=Crei  
e)? .r9pA;  
public String getSFilePath() =|y9UlsD  
{ j[J-f@F \Y  
return sFilePath; E,x+JeKV  
} wc^tgE  
X[BIA+6  
0)e\`
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public void setSFilePath(String value) A&Usddcp  
{ ~/iKh11  
sFilePath = value; 9`X\6s  
} 1FL~ndJs  
LxSpctiNx  
>7T'OC  
public String getSFileName() h_3E)jc  
{ 0#Y5_i|p  
return sFileName; a:OQGhc=  
} `MN4uC  
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u?<%q!  
public void setSFileName(String value) (Y?gn)*t  
{ [ =9T*Sp  
sFileName = value; ep)n_!$OH"  
} `V)8 QRN(  
Em
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' ;FnIZ  
public int getNSplitter() Ma']?Rb`  
{ ;~ $'2f
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return nSplitter; tOd&!HYL  
} vDhh>x(  
B:S>wFE(.  
i
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public void setNSplitter(int nCount) }t=!(GOb}  
{ }"P|`"WW  
nSplitter = nCount; b)5uf'?-  
} P90yI  
} H0gbSd+  
 eFTpnG  
g<;q.ZylT  
/* ?*1uN=oI{*  
**Utility.java o!Ieb  
*/ ;yLu R  
package NetFox; l<LP&  
{ VfXsI  
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public class Utility { Zd}9O jz5  
m_
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public Utility() #64-~NVL_  
{ (pCrmyB  
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} ~IfJwBn-i  
n&;85IF1  
//线程睡眠 TA`1U;c{n  
public static void sleep(int nSecond) =_ ./~  
{ vkx7paY_  
try{ 
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Thread.sleep(nSecond); 'qb E=  
} t~EPn.  
catch(Exception e) ]7F=u!/`<C  
{ r4XK{KHn  
e.printStackTrace (); p;59?  
} gx8ouOh  
} k"T}2 7  
$m%fwB  
//日志 mAj?>;R2$2  
public static void log(String sMsg) ,j2Udn}  
{ T@:Wp4>69  
System.err.println(sMsg); 9~5
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} jrlVvzZ  
~Ei$nV  
,]ma+(|  
public static void log(int sMsg) tqvN0vY5  
{
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System.err.println(sMsg); {W=%U|f  
} t7dt*D_YqK  
} 4n!aW?%  
nQX:T;WL@  
uD$u2  
/* hk(ZM#Bh  
**TestMethod.java <EB+1GFuI  
*/ B:;pvW]  
package NetFox; 8>2.UrC  
j9x<Y]  
fcRxp{*zO  
public class TestMethod { 'RQ+g}|Ba!  
xd q?/^E  
g:'xae/]S  
public TestMethod() 
3nIU1e  
{ ///xx/weblogic60b2_win.exe fo*2:?K&  
try{ H1pO!>M  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =)H.cuc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); w(*vj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); '8RsN-w  
fileFetch.start(); Bw)/DM]  
} F#,90F'  
catch(Exception e){e.printStackTrace ();} )BZ.Sv  
KQaxvU)L  
@w#-aGJO  
} q1$N>;&  
JIEK*ui  
uB]7G0g:  
public static void main(String[] args) $<dH?%!7  
{ <y2U3;t  
new TestMethod(); fnjPSts0  
} _wbF>z  
} n71r_S*  
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