http断点续传简单实现（java)

/* *)6\V}`  
**SiteFileFetch.java N#t`ZC&m'  
*/ c$tX3ug6I  
package NetFox; :XG~AR/  
import java.io.*; >V)"TZH  
import java.net.*; gw[Eu>I  
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public class SiteFileFetch extends Thread { h8(>$A-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean >!a- "  
long[] nStartPos; //开始位置 /@
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long[] nEndPos; //结束位置 gTU5r4xm~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;B[(~LCyT  
long nFileLength; //文件长度 ; D/6e6  
boolean bFirst = true; //是否第一次取文件 dl6U]v=  
boolean bStop = false; //停止标志 dt+r P%  
File tmpFile; //文件下载的临时信息 <'SS IMr  
DataOutputStream output; //输出到文件的输出流 %9Z0\ a)[  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $uyx  
public SiteFileFetch(SiteInfoBean bean) throws IOException >8=lX`9f{  
{ 0.w7S6v|&  
siteInfoBean = bean; UOl*wvy  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }f?[m&<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) A~<!@`NjB  
{ [(5.?  
bFirst = false; `&OX|mL^w  
read_nPos(); } e+`Kxy  
} 0`-b57lF&  
else 5Pn.c!  
{ %DXBl:!Y`  
nStartPos = new long[bean.getNSplitter()]; K%x]:|,>M  
nEndPos = new long[bean.getNSplitter()];
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} tH.L_< N  
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} {B4qeG5  
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public void run() vO~Tx  
{ +qC[X~\  
//获得文件长度 ]S[?tn  
//分割文件 0F/[GZ<k  
//实例FileSplitterFetch 3]mprX'  
//启动FileSplitterFetch线程 T]-MrnO  
//等待子线程返回 Y7r;}^+WY  
try{ }l[e@6r F  
if(bFirst) U$& '>%#  
{ >Bf3X&uS  
nFileLength = getFileSize(); 2%`= LGQC  
if(nFileLength == -1) +,LWyvc'  
{ 4_U
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System.err.println("File Length is not known!"); dgoAaS2M  
} HdB>CVuh  
else if(nFileLength == -2)
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{ .O5V;&,
  
System.err.println("File is not access!"); Mh5> hD  
} Q[rZ1z  
else Rk3 bZvj3  
{ AguE)I&m  
for(int i=0;i<nStartPos.length;i++) /[\g8U{5B}  
{ C)EP;5k'!\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); A`Y^qXFb`  
} d!0rq4v7  
for(int i=0;i<nEndPos.length-1;i++) .7gh2K  
{ WK(X/!1/k  
nEndPos = nStartPos[i+1]; UgS`{&
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} x"NQatdq  
nEndPos[nEndPos.length-1] = nFileLength; 86Q3d%;-yo  
} _Tor9Tj  
} 4Zwbu  
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//启动子线程 <%S)6cw(3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3J &Ros  
for(int i=0;i<nStartPos.length;i++) fPUr O  
{ VYkh
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6` TwP\!$/  
nStartPos,nEndPos,i); /[FDiJH2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Zdqm|_R[  
fileSplitterFetch.start(); |;wc8;  
} gI;"PkN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `7:uc@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \\KjiT'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", NF6xKwRU]_  
nEndPos = " + nFileLength); {Fw"y %a^  
// fileSplitterFetch[nPos.length-1].start(); Rq5'=L  
s~A-qG>  
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//等待子线程结束 goIvm:
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//int count = 0; ~. vridH  
//是否结束while循环 S1U0sP@o  
boolean breakWhile = false; (!5Ta7X  
o
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while(!bStop) S7f.^8  
{ Y_:jc{?  
write_nPos(); b3E1S+\=~  
Utility.sleep(500); .c+U=bV-  
breakWhile = true; <7\j\`  
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for(int i=0;i<nStartPos.length;i++) .s*N1 U?h  
{ F8?2+w@P  
if(!fileSplitterFetch.bDownOver)
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{ /x ?@Mn>  
breakWhile = false; fe/;U=te  
break; .b3h?R*&  
} ,X^3.ILz  
} 8O'bCBhv  
if(breakWhile) S9Yzvq!(  
break; 3d6z_Yd:  
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//count++; c#{lXS^  
//if(count>4) MOaI~xZ  
// siteStop(); iF^qbh%%E  
} ^:{8z;w!(  
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System.err.println("文件下载结束！"); l[$GOLeS  
} HfVHjF)  
catch(Exception e){e.printStackTrace ();} ?uSoJM`wa!  
} FAdTm#tgW]  
. fja;aG  
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//获得文件长度 `CS\"|z  
public long getFileSize() Lxp}o7>K  
{ GLtWo+g0  
int nFileLength = -1; ,6;n[p"h|r  
try{ *pwkv7Zh  
URL url = new URL(siteInfoBean.getSSiteURL()); gvuv>A}vJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O3o^%0  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xs052c|s  
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int responseCode=httpConnection.getResponseCode(); ~-A"j\gi"  
if(responseCode>=400) Z|n|gxe  
{ r&4Xf#QD6  
processErrorCode(responseCode); =;0-t\w!  
return -2; //-2 represent access is error 'r]6 GC8Z$  
} Z8$BgP  
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}( F:U#  
String sHeader; p*Q-o  
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for(int i=1;;i++) u?`{s88_mF  
{ $^iio@SW{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ruGJZAhIA^  
//Utility.log(in.readLine()); yk8b>.Y\A  
sHeader=httpConnection.getHeaderFieldKey(i); Ljm`KE\Q;t  
if(sHeader!=null) `#ruZM066  
{ D;> 7y}\  
if(sHeader.equals("Content-Length")) 'z8FU~oU  
{ t,fec>.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); uM`i!7}  
break; jlj ge=#c2  
} )ovAGO  
} .b]sQ'  
else "KP]3EyPc  
break; >;MJm  
} Q<V(#)*  
} 61H_o7XXk  
catch(IOException e){e.printStackTrace ();} Xb%Q%"?~  
catch(Exception e){e.printStackTrace ();} vWoppt  
/*y5W-'d^  
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Utility.log(nFileLength); ^ 0YQlT98  
>*{k~Y-G  
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return nFileLength; wmGcXBHt$  
} T<0r,  
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//保存下载信息（文件指针位置） =\.*CY|;N  
private void write_nPos() xZ`z+
)  
{ (-WRZLOQ  
try{ t\ oud{Cv  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |)!f".`  
output.writeInt(nStartPos.length); z+yq%O  
for(int i=0;i<nStartPos.length;i++) kZG.Id  
{ kAEq+{h  
// output.writeLong(nPos); 33DP?nI}  
output.writeLong(fileSplitterFetch.nStartPos); 5=C?,1F$A  
output.writeLong(fileSplitterFetch.nEndPos); "HJ^>%ia  
} T9V=#+8#"  
output.close(); Bn]=T  
} I/njyV)H  
catch(IOException e){e.printStackTrace ();} $97O7j@  
catch(Exception e){e.printStackTrace ();} /8e}c`  
} cRf F!EV  
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//读取保存的下载信息（文件指针位置） G
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private void read_nPos() *eoH"UFYQ#  
{ d/9YtG%q  
try{ m&gd<rt/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3l<qcKKc  
int nCount = input.readInt(); f/J/tt  
nStartPos = new long[nCount]; -kk7y  
nEndPos = new long[nCount]; $L= Dky7  
for(int i=0;i<nStartPos.length;i++) .hmeP MK  
{ \eKXsO"d  
nStartPos = input.readLong(); ym{@w3"S  
nEndPos = input.readLong(); AT1cN1:4?  
} >"2jCR$/  
input.close(); A6=Z2i0w>X  
} u*@R`,Y   
catch(IOException e){e.printStackTrace ();} 8S#$'2sT  
catch(Exception e){e.printStackTrace ();} C!^A\T7p  
} et+lL"&

 
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private void processErrorCode(int nErrorCode) FXBmatBck  
{ &Gh,ROo4  
System.err.println("Error Code : " + nErrorCode); Nl YFS?5  
}  9Do75S{(  
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//停止文件下载 4JK6<Pk  
public void siteStop() i$] :Y`3h  
{ *Vl#]81~  
bStop = true; o>M^&)Xs  
for(int i=0;i<nStartPos.length;i++) .F7?}8>Z  
fileSplitterFetch.splitterStop(); LKvX~68  
S} UYkns*  
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} fSbLkd 9  
} ]z'L1vQl7  
//负责部分文件的抓取 IQ<G.  
**FileSplitterFetch.java b~&cYk'  
*/ :0y-n.-{  
package NetFox; 9R$$(zB 1;  
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import java.io.*; !LH;K  
import java.net.*; lx2#C9L_  
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public class FileSplitterFetch extends Thread { Xi"9y @  
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String sURL; //File URL p|->z  
long nStartPos; //File Snippet Start Position 6kp)'wz`  
long nEndPos; //File Snippet End Position A~Sc ] M  
int nThreadID; //Thread's ID (DvPdOT+3  
boolean bDownOver = false; //Downing is over WILa8"M  
boolean bStop = false; //Stop identical f.J^HQ_  
FileAccessI fileAccessI = null; //File Access interface *66EkCj  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s7yKxg+`{  
{ Pa{DB?P  
this.sURL = sURL; &5K3AL  
this.nStartPos = nStart; uH$hMg  
this.nEndPos = nEnd; !PoyM[Z"f  
nThreadID = id; ^ q ba<#e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 iWeUsS%zpV  
} 5)f 'wVe  
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public void run() 8*8Y\"  
{ e/Z{{FP%6  
while(nStartPos < nEndPos && !bStop) 6?}|@y^fb  
{ ,2!7iX  
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try{ m>Wt'Cc  
URL url = new URL(sURL); B>E4,"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7Q{&L#;  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4wKCzPy  
String sProperty = "bytes="+nStartPos+"-"; Fb<'L5
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httpConnection.setRequestProperty("RANGE",sProperty); EUt2S_2P  
Utility.log(sProperty); z}J~X%}e  
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InputStream input = httpConnection.getInputStream(); -ioO8D&!  
//logResponseHead(httpConnection); gAvNm[=wD2  
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byte[] b = new byte[1024]; )Mq4p'*A[  
int nRead; LT{g^g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) X_-/j.  
{ "d/54PKWx  
nStartPos += fileAccessI.write(b,0,nRead); T#rUbi>""  
//if(nThreadID == 1) &O+S[~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |b@`ykD  
} tPiC?=4R  
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Utility.log("Thread " + nThreadID + " is over!"); w\ '5lk,"  
bDownOver = true; M GC=L .  
//nPos = fileAccessI.write (b,0,nRead); 9Q(Lnu  
} zz3{+1w]  
catch(Exception e){e.printStackTrace ();} B[sI7D>Y  
} evEdFY  
} S~ckIN]
 
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//打印回应的头信息 clqFV   
public void logResponseHead(HttpURLConnection con) q) 5s'(  
{ i|H^&$|  
for(int i=1;;i++) ii`,cJl  
{ 'O~_g5kC  
String header=con.getHeaderFieldKey(i); De$Ic"Z9L  
if(header!=null) MIr[_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Xl$r720ZJr  
Utility.log(header+" : "+con.getHeaderField(header)); hT=E~|O  
else O:V.;q2]U  
break; &Kc45  
} %QDAog  
} }}Q h_(  
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public void splitterStop()  [K
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{ C.=%8|Zy  
bStop = true; }rVLWt
 
} C]ho7qC  
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} J'#o6Ud  
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/* <vg|8-,#m  
**FileAccess.java Ktuv a3=>N  
*//文件访问(定位，写) pTQ7
woj}  
package NetFox; _NuHz  
import java.io.*; 2MXg)GBcU>  
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public class FileAccessI implements Serializable{ &xj,.;
  
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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 r,,*kE  
RandomAccessFile oSavedFile; R=NK3iGTf  
long nPos; hNcEBSQ  
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public FileAccessI() throws IOException 4}Os>M{k  
{ v{SYz<(  
this("",0); tPJU,e)  
} 4GJx1O0Ol  
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 #s=\  
public FileAccessI(String sName,long nPos) throws IOException d8jP@
>  
{ j}%C;;MPH  
oSavedFile = new RandomAccessFile(sName,"rw"); %E":Wv  
this.nPos = nPos; ac43d`wpK  
oSavedFile.seek(nPos); yW(A0  
} XC[AJ!q`  
BYI13jMH+Y  
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public synchronized int write(byte[] b,int nStart,int nLen) {y!77>Q/  
{ rj eKG-Z@  
int n = -1; :n}t7+(>U  
try{ UD'e%IVw  
oSavedFile.write(b,nStart,nLen); f,+ONV]5Tt  
n = nLen; (aq^\#9btO  
} XKBQH(  
catch(IOException e) L#T`h}1Z  
{ scEE$:  
e.printStackTrace (); 6~Z
q  
} y5V]uQSD  
]\=M$:,RZ  
8{.:$T  
return n; lgCOp%>  
} OB+I.
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} aj]%c_])(  
0 KWi<G1  
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/* \xtmd[7lb<  
**SiteInfoBean.java j98>Jr\  
*/ u $T'#p1  
package NetFox; <Y#EiC.  
/I#SP/M&l  
%$(*.o!+8  
public class SiteInfoBean { }15ooe%  
0'y3iar  
c:`&QDF  
private String sSiteURL; //Site's URL 9y"\]G77E  
private String sFilePath; //Saved File's Path ?37Kc,o  
private String sFileName; //Saved File's Name r`=!4vY2  
private int nSplitter; //Count of Splited Downloading File z9*7fT  
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cM+s)4TPL  
public SiteInfoBean() d
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{//nSplitter的缺省值为5 T EqCoeR  
//default value of nSplitter is 5 aSNTm8SYX  
this("","","",5); |(1z ?Spbe  
} N|WR^MQD  
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RiAY>:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) sJ/?R:  
{ YR/rN,  
sSiteURL= sURL; n&uD=-  
sFilePath = sPath; @k2nID^>  
sFileName = sName; }3mIj<I1;  
this.nSplitter = nSpiltter; ]2B=@V t,  
a?9Ka!O4s  
>&N8Du*[  
} M&O .7B1}  
t[cZ|+^]  
1QH5<)Oa  
public String getSSiteURL() {wp"zaa  
{ owc#RW9 7  
return sSiteURL; > jvi7  
} 3YPoObY  
ng[ZM);  
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public void setSSiteURL(String value) [2cG 7A  
{ sHulaX{  
sSiteURL = value; b]U%|bp  
} 9ozUg,+Z|J  
Z:}d\~`x$%  
"#mr?h_  
public String getSFilePath() p} }=li>  
{ 6<<i
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return sFilePath; :Yqi5CR  
} A#j'
JA>_  
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'PrrP3lO_~  
public void setSFilePath(String value) {wx!~K  
{ Y/_b~Ahn  
sFilePath = value; IGd]!  
} BI-xo}KI  
@{!c [{x,T  
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public String getSFileName() J@c)SK%2h  
{ n-n{+Dl!  
return sFileName; RcH",*U  
} N&t+*kF_  
A/EW57v"  
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public void setSFileName(String value) >;.'$-  
{ (r?41?5K  
sFileName = value; cmv&!Egd  
} QvH=<$  
Zg/ra1n  
#;6YADk2_  
public int getNSplitter() g2v0!  
{ ?_9A`LC*  
return nSplitter; kN*,3)T;}  
} J!,<NlP0K  
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public void setNSplitter(int nCount) Vn-y<*np  
{ ;V~[kF=t0  
nSplitter = nCount; c_li.]P  
} \ueo^p]_?  
} pAo5c4y!4  
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gSP]& _9j  
/* J]A!>|Ic  
**Utility.java c3&;Y0SD  
*/ E}d@0C:  
package NetFox; {re<S<j&  
lV-b  
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public class Utility { *1fq:--  
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e:E:"elr]  
public Utility() c-L1 Bkw  
{ B6&;nU>;  
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qJb9JL$s  
} 6.| {l8%r  
:O}=$[  
//线程睡眠 i"~J -{d}  
public static void sleep(int nSecond)  ]CD  
{ 'Tni;  
try{ m?]XNgT  
Thread.sleep(nSecond); bZ0mK$B  
} ?H\K];  
catch(Exception e) @-9I<)Z/2  
{ "|yuP1;L  
e.printStackTrace (); 0HA`  
}
eot]VO:  
} g?.ls{H  
ab5 a>w6}  
//日志 XjL)WgQ{i  
public static void log(String sMsg) dBKL_'@@}  
{ KErQCBeJ  
System.err.println(sMsg); {;6Yi!  
} t%$>  
X\:;A{  
r5kKNyJ  
public static void log(int sMsg)  x w8 e  
{ S:IhJQ4K  
System.err.println(sMsg); cRm+?/  
} $[L~X M  
} ALVHKL2  
C:+-T+m[  
\a+.~_iL|  
/* 5\MCk"R!  
**TestMethod.java >YwvM=b"V  
*/ ztcV[{[g  
package NetFox; n.&z^&$w\)  
6ge,2[PU  
/UP&TyZ  
public class TestMethod { ;x/do?FbT  
^Oy97Y  
?/Bp8q(  
public TestMethod() )N4!zuSVf  
{ ///xx/weblogic60b2_win.exe F<K;tt  
try{ cI~uI'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); z']TRjDbT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3mI(5~4A]?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tI42]:z  
fileFetch.start(); -?_#Yttu  
} AI{Tw>hZ  
catch(Exception e){e.printStackTrace ();} ;m<22@,E&  
d<{>&  
{t<E*5N]a  
} ~:`5Y"Av:  
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0!<qfT a  
public static void main(String[] args) |$*1!pL-QP  
{ S{HAFrkm7  
new TestMethod(); BG>fLp  
} -MEp0  
} 1:!_AU?  
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