http断点续传简单实现（java)

/* c#fSt}J>C  
**SiteFileFetch.java -ozcK  
*/ wr6(C:  
package NetFox; #<w2xR]:  
import java.io.*; dhr-tw  
import java.net.*; llpgi,-=  
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t1o_x}z4.  
public class SiteFileFetch extends Thread { 3`njQvI\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean //
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long[] nStartPos; //开始位置 9@ ^*\s  
long[] nEndPos; //结束位置 OL@' 1$/A  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2 3A)^j  
long nFileLength; //文件长度 S<++eu  
boolean bFirst = true; //是否第一次取文件 g`H;
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boolean bStop = false; //停止标志 uX&Tn1Kg  
File tmpFile; //文件下载的临时信息 6#2E {uy;R  
DataOutputStream output; //输出到文件的输出流 /8>we`4  
P#2#i]-  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Rap_1o9#\  
public SiteFileFetch(SiteInfoBean bean) throws IOException <'P+2(Oi  
{ Ke\FzZ]  
siteInfoBean = bean; U]iZ3^8VT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W=!D[G R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5e c T.  
if(tmpFile.exists ()) 6"o@d8>v  
{ )!l1  
bFirst = false; iuoZk5O  
read_nPos(); KyzdJ^xC"  
} 9+frxD&pO  
else hh^_Z| 5  
{ !4+@b s  
nStartPos = new long[bean.getNSplitter()]; {MmK:C  
nEndPos = new long[bean.getNSplitter()]; cq1)b\|  
} xcXnd"YYE  
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} fSm|anuKZe  
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public void run() SM
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{ {mB &xz:b  
//获得文件长度 {&)E
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//分割文件 #D8u#8Dz  
//实例FileSplitterFetch 'n"n;  
//启动FileSplitterFetch线程 \.MPjD  
//等待子线程返回 >m`<AynJ  
try{ !4fT<V(  
if(bFirst) Y^}c+)t  
{ A}0u-W  
nFileLength = getFileSize(); P<R'S  
if(nFileLength == -1) PWN$x`h g[  
{ 7V;wCm#b  
System.err.println("File Length is not known!"); >L88`  
} 9*xv ,Yz8  
else if(nFileLength == -2) -T.C?Q g  
{ <Lfo5:.  
System.err.println("File is not access!");  LhtA]z,m  
} G\H|\i  
else K]Z];C#)  
{ MVe4[<  
for(int i=0;i<nStartPos.length;i++) \yA*)X+  
{ SQI =D8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {'q(a4  
} -ob1_0  
for(int i=0;i<nEndPos.length-1;i++) hkvymHaG  
{ |6zx YuX  
nEndPos = nStartPos[i+1]; Hu7WU;w  
} "v5jYz5M  
nEndPos[nEndPos.length-1] = nFileLength; @DCw(.k*
 
} d?1[xv;  
} 9 IY1"j0O  
|F52)<\  
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//启动子线程 #~;:i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;Qdw$NuW  
for(int i=0;i<nStartPos.length;i++) Te&5IB-  
{ ~#9(Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !l#n.Fx&3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6^hCW`jG  
nStartPos,nEndPos,i); ](sT,'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \={A%pA;@{  
fileSplitterFetch.start(); U jB5Xks  
} U
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "A3V(~%!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %&S :W%qm?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", j<_)Y(x>  
nEndPos = " + nFileLength); ?wbf)fbq  
// fileSplitterFetch[nPos.length-1].start(); pwr]lV$w  
5s=L5]]r_j  
s%S; 9T  
//等待子线程结束 'jd fUB  
//int count = 0; C;oT0(  
//是否结束while循环 'n4 iW  
boolean breakWhile = false; S"Mm_<A$@  
OE_A$8L  
];au! _o  
while(!bStop) ?<eH!MHF  
{ *odwg$  
write_nPos(); kU[#. y=%p  
Utility.sleep(500); ? EXYLG  
breakWhile = true; QB#rf='  
e6hfgVN  
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for(int i=0;i<nStartPos.length;i++) C(lGW,!  
{ "}jv5j5  
if(!fileSplitterFetch.bDownOver) lc\f6J>HT  
{
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breakWhile = false; ;\)N7SJ  
break; !d3:`l<  
} WeRX~  
} #tQ__V   
if(breakWhile) `{W>Dy  
break; G}p*oz~  
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Dro2R_j{  
//count++; b;Uqyc  
//if(count>4) +C){&/=#  
// siteStop(); u
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} 8+OcM ;0  

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L&h90Az1W  
System.err.println("文件下载结束！"); /yO|Q{C}M8  
} $z*Y:vFP  
catch(Exception e){e.printStackTrace ();} w2e9Ue~WH  
} +'QE-#%{=  
=hDFpb,mr  
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//获得文件长度 f%5 s8)  
public long getFileSize() ?_Y2'O  
{  VqK/GWg  
int nFileLength = -1; yUp"%_t0  
try{  /DN!"  
URL url = new URL(siteInfoBean.getSSiteURL()); 2C_/T8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *Z C$DW!-  
httpConnection.setRequestProperty("User-Agent","NetFox"); Hlye:.$  
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int responseCode=httpConnection.getResponseCode(); a>XlkkX  
if(responseCode>=400) $3Srr*  
{ qJf=f3  
processErrorCode(responseCode); :Vl2\H=P  
return -2; //-2 represent access is error ;Alw`'  
} m03]SF(#3  
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t~@
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String sHeader; w*7BiZ{s<  
0)T`&u3!  
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for(int i=1;;i++)
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{ F9 q9BH  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F1UTj"
<e  
//Utility.log(in.readLine()); #>@~3kGg  
sHeader=httpConnection.getHeaderFieldKey(i); bQ6<R4  
if(sHeader!=null) dyMj=e  
{ [
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if(sHeader.equals("Content-Length")) Dhy@!EOS  
{ vgvJ6$#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); rLzN#Zoi  
break; xD3Y-d9  
} `oUuAL  
} mhZ60RW  
else {Mx3G*hr
 
break; "<5su5]  
} 60r4%>d  
} =& .KKr  
catch(IOException e){e.printStackTrace ();} [$[1|r *Q  
catch(Exception e){e.printStackTrace ();} ^jxV  
`(@}O?w!1  
{3{cU#\QA  
Utility.log(nFileLength); F1aI4H<(T  
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return nFileLength; g<&n V>wF  
} -p\uW0XA  
N! N>/9  
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//保存下载信息（文件指针位置） )r^)e4UI  
private void write_nPos() 4W$t28)  
{ Fv(1A_~IS  
try{ vq&u19iP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); nNJMQb'K  
output.writeInt(nStartPos.length); q" aUA_}\  
for(int i=0;i<nStartPos.length;i++) 2IGoAt>V  
{ 4C
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// output.writeLong(nPos); O)E8'Oe"Q  
output.writeLong(fileSplitterFetch.nStartPos); /degBL+  
output.writeLong(fileSplitterFetch.nEndPos); <B%s9Zy  
}
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output.close(); xOAA1#  
} ~$\9T.tre2  
catch(IOException e){e.printStackTrace ();} Fw!TTH6l0  
catch(Exception e){e.printStackTrace ();} E,nxv+AQ  
} q;<=MO/  
m5/d=k0l  
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//读取保存的下载信息（文件指针位置） f8c'`$O  
private void read_nPos() _R 6+bB$  
{ ySEhi_)9^  
try{ Xi~%,~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2l#c?]TA  
int nCount = input.readInt(); YAoGVey  
nStartPos = new long[nCount]; f,_EPh>  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) <*4BT}r,^2  
{ BD(Y=g  
nStartPos = input.readLong(); >.)m|,  
nEndPos = input.readLong(); :g`j gn0  
} ][IEzeI_LN  
input.close(); )* \N[zm  
} d}2$J1`  
catch(IOException e){e.printStackTrace ();} wG\ +C'&~  
catch(Exception e){e.printStackTrace ();} Jiv%Opo/|  
} WE|-zo  
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private void processErrorCode(int nErrorCode) S);SfNh%CL  
{ )*wM DM5q  
System.err.println("Error Code : " + nErrorCode); E1&9( L5  
} 4%s6 d,6"  
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7|/Ct
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//停止文件下载 $yA>
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public void siteStop() x&kM /z?/  
{ ~5Cid)Q}@o  
bStop = true; K_" denzT+  
for(int i=0;i<nStartPos.length;i++) TOe=6
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fileSplitterFetch.splitterStop(); /#C}1emK  
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} :~Z-K\  
} }CCTz0[D"  
//负责部分文件的抓取 d}Y\;'2,  
**FileSplitterFetch.java aGR!T{`  
*/ "nzQ$E>?$  
package NetFox; 9 Y-y?Y  
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import java.io.*; dN%
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import java.net.*; Fzc8)*w  
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public class FileSplitterFetch extends Thread { Pd"=&Az|  
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String sURL; //File URL 1j!LK-  
long nStartPos; //File Snippet Start Position w I7iE4\vz  
long nEndPos; //File Snippet End Position
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int nThreadID; //Thread's ID ;tZ;C(;
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boolean bDownOver = false; //Downing is over k"z ~>  
boolean bStop = false; //Stop identical I+4#LR3;  
FileAccessI fileAccessI = null; //File Access interface =G9 9U/  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5!b+^UR;z  
{ $Sx(
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this.sURL = sURL; /~O>He  
this.nStartPos = nStart; j^Vr!y  
this.nEndPos = nEnd; 6VsgZ"Il  
nThreadID = id; x/B1\U I  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 UK7pQt}9  
} p";5J+?(  
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public void run() Hrk]6*  
{ \|gE=5!Am=  
while(nStartPos < nEndPos && !bStop) z[0+9=<Y  
{ <0w"$.K#3  
cR*5iqA   
2:6W_[7l!  
try{ <y}9Twdy  
URL url = new URL(sURL); l 10p'9n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g5OKhL0u  
httpConnection.setRequestProperty("User-Agent","NetFox"); x%!Ea{s  
String sProperty = "bytes="+nStartPos+"-"; n`Y"b&  
httpConnection.setRequestProperty("RANGE",sProperty); _&wrA3@/L  
Utility.log(sProperty); Z"pCDW)  
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InputStream input = httpConnection.getInputStream(); wqnHaWd*  
//logResponseHead(httpConnection); 6${=N}3Kw  
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byte[] b = new byte[1024]; i!a.6Gq  
int nRead; )/y7Fh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3i;sB
 
{ .DX-biX,  
nStartPos += fileAccessI.write(b,0,nRead); x@)G@'vV|  
//if(nThreadID == 1) 'nMj<:0wlD  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6L!/#d0  
} \2c3Nsra  
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++=f7yu  
Utility.log("Thread " + nThreadID + " is over!"); %4QpDt  
bDownOver = true; ;}dvc7  
//nPos = fileAccessI.write (b,0,nRead); s?5vJ:M Xr  
} mp:xR^5c  
catch(Exception e){e.printStackTrace ();} Z^[ ]s1iP}  
} Img$D*BM  
}  Nt w?~%  
0z =?}xr  
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//打印回应的头信息 ?]AF? 0/  
public void logResponseHead(HttpURLConnection con) gr^TL1(  
{ JE*d-  
for(int i=1;;i++) bl3?C  
{ $ o }  
String header=con.getHeaderFieldKey(i); MtD0e@  
if(header!=null) DuMzK%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (k^o[HF  
Utility.log(header+" : "+con.getHeaderField(header)); ,6 IKkyD  
else +Zg@X.z  
break; cF
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} *8I"7'xh  
} )vsX (/WU  
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public void splitterStop() SYd6D@^2j  
{ xjy(f~'  
bStop = true; 8-PHW,1@a3  
} W;T5[
 
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} t}YT+S  

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<5 }  
/* vk4Q2P  
**FileAccess.java r,HIoeAKP  
*//文件访问(定位，写) q"e]\Tb=we  
package NetFox; $3=S\jyfK  
import java.io.*; nCS" l5  
`*ALb|4ilG  
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public class FileAccessI implements Serializable{ {ldt/dl~  
bP Q=88*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6E#znRi6IE  
RandomAccessFile oSavedFile; dSI<s^n  
long nPos; we/sv9v}n  
cSTF$62E  
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public FileAccessI() throws IOException v{X<6^g  
{ .%EYof  
this("",0); NZ"nG<;5  
} r])V6 ^U  
82M`sk3.  
SU5O+;{`'  
public FileAccessI(String sName,long nPos) throws IOException G1fC'6$3  
{ cN-$;Ent  
oSavedFile = new RandomAccessFile(sName,"rw"); jVPX]8  
this.nPos = nPos; SJ2l6  
oSavedFile.seek(nPos); al"=ld(  
} L++qMRk9  
D&{CC  
kMx)G]  
public synchronized int write(byte[] b,int nStart,int nLen) ;pw9+zo^M  
{ fKW)h?.Kd  
int n = -1; =NmW}x|n  
try{ mxE
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oSavedFile.write(b,nStart,nLen); cgi:"y F  
n = nLen; b_X&>^4Dkl  
} ,M9e *  
catch(IOException e) [w90gp1O[  
{ v5F+@ug  
e.printStackTrace (); :8`~dj.  
} #g/m^8n?s  
@THa[|(S  
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return n; O6ph_$nt.  
} [MuZ^'dR  
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} /i~x.i3  
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S Rk%BJ? ~  
/* Ci4;e  
**SiteInfoBean.java H:)_;k  
*/ @^Rl{p  
package NetFox; UM/!dt}DnF  
{;N2 &S o  
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public class SiteInfoBean { .DI?-=p|_#  
osl\j]U8  
2qot(Zs1i  
private String sSiteURL; //Site's URL K3Bw3j 9  
private String sFilePath; //Saved File's Path e#)NYcr6  
private String sFileName; //Saved File's Name P{x6e/  
private int nSplitter; //Count of Splited Downloading File %Zp|1J'"  
!S%0#d2  
1F_$[iIX]  
public SiteInfoBean() \,fa"^8  
{//nSplitter的缺省值为5 _, E/HAX  
//default value of nSplitter is 5 Cs(sar:7  
this("","","",5); >(-A"jf  
} *4e?y  
\1SC:gN*#  
i),bAU!+m  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ap8q`a{j^  
{ 4l7 Ny\J  
sSiteURL= sURL; zn>+
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sFilePath = sPath; wBvVY3VQ^  
sFileName = sName; =P%&]5ts  
this.nSplitter = nSpiltter; ;{aGEOP'U  
`U=Jbdc l3  
$H)QUFyC  
} t.dr<   
*NG\3%}%|@  
b50mMWtG  
public String getSSiteURL() xKl1DIN[  
{ /z_]7]  
return sSiteURL; 1+gFfKq  
} h!ogH >S~  
b8_F2  
|j-ng;  
public void setSSiteURL(String value) $_iE^zZaU^  
{ 4&=</ok6`0  
sSiteURL = value; JEk'2Htx  
}  DR{O.TX  
3@qv[yOE  
op\$(7<d-  
public String getSFilePath() FZ
?:BX^  
{ yx|{:Li!  
return sFilePath; qDG2rFu&[  
} T
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.9J}Z^FD  
P6O\\,B1A  
public void setSFilePath(String value) 6UqAs<
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{ vJaWHC$q  
sFilePath = value; h=
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} P%)r4+at  
.>eRX%  
XPU>} 4{  
public String getSFileName() |1"&[ .  
{ EG`6T  
return sFileName; k#zDY*kj  
} 9(J,&)J  
n|{#5#  
SDC'S]{ew  
public void setSFileName(String value) N[e,%heR  
{ 5 ty2e`~K  
sFileName = value; /IG{j}  
} ROmmak(y8  
-2; 6Pwmv  
6^WNwe\  
public int getNSplitter() bY2R/FNL=  
{ 3i7E
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return nSplitter; w;gk=<_  
} tc0;Ake-&  
q~b# ml2QS  
":8\2Qp  
public void setNSplitter(int nCount) ]c~yMA+]FZ  
{ Uffwzd!  
nSplitter = nCount; *d3-[HwZCL  
} 8W{M}>;[9  
} [B#XA}w  
9zb1t1[W  
mmbe.$73  
/* @t~y9UfF  
**Utility.java 7;o:r$08&}  
*/ S)rr  
package NetFox; v>#Njgo  
`VKFA<T  
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public class Utility { }q`9U!v  
X'jyR:ut#  
?a3wBy  
public Utility() +7}^Y}(  
{ aWIkp5BFj  
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7%i'F=LzT  
} hqvhnqQk  
X7huc*  
//线程睡眠 $C;i}q#  
public static void sleep(int nSecond) b^Z2Vf:k]  
{ G;}WZy  
try{ D[/fs`XES  
Thread.sleep(nSecond); ?@9v+Am!  
} 6X*vCylI  
catch(Exception e) s|e.mZk/  
{ ud r\\5  
e.printStackTrace (); Yi%lWbr  
} (|K+1R  
} x*7A33@i  
"-$}GUK?Z  
//日志 %-!%n=P  
public static void log(String sMsg) XnZ$%?$  
{ x.*^dM@V  
System.err.println(sMsg); KsP2./N  
} <E4(KE  
Tse#{  
~^1y(-cw  
public static void log(int sMsg) UHZ&7jfl  
{ 5_aj]"x  
System.err.println(sMsg); k_,7#:+  
} QQS*r}>  
} |@u2/U9  
;[}OZt  
f%,S::%Ea  
/* D<6$@ZJ  
**TestMethod.java reN\|?0{  
*/ Xe%J{  
package NetFox; IQPu%n{0v  
l&ueD&*4&  
1 %P-X!  
public class TestMethod { (N9-YP?qm  
JB~^J5#[Oh  
KSPa2>lz?  
public TestMethod() gB'ajX=OA/  
{ ///xx/weblogic60b2_win.exe _
d@YLd78P  
try{ ; BN81;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |Gf<Ql_.4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V1]GOmXz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <R7{W"QTA)  
fileFetch.start(); Zo<)r2|O.  
} <a"(B*bBd  
catch(Exception e){e.printStackTrace ();} U3{<+vSR`  
Z<i}XCE  
v0\l~_|H  
} l<+[l$0#  
]eKuR"ob0  
CM_hN>%w[  
public static void main(String[] args) :hZM$4  
{ ]o<]A[<  
new TestMethod(); Kz"3ba}KH  
} idYB.]Y(  
} ?:\/-y)Sp  
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