http断点续传简单实现（java)

/* /b@8#px  
**SiteFileFetch.java iZwt,)(  
*/ UOy`N~\gh+  
package NetFox; O9dIobu4  
import java.io.*; 2u*o/L+  
import java.net.*; NK~j>>^;v  
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I|n<B"Q6^  
public class SiteFileFetch extends Thread { @i$9c)D  
9`$fU)K[Pl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /al(=zf  
long[] nStartPos; //开始位置 1ePZs$   
long[] nEndPos; //结束位置 l~!\<, !  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 liA)|.H  
long nFileLength; //文件长度 #dtYa  
boolean bFirst = true; //是否第一次取文件 JC_Y#kN@z  
boolean bStop = false; //停止标志 S c_*L<$  
File tmpFile; //文件下载的临时信息 @F+4 NL-'P  
DataOutputStream output; //输出到文件的输出流 a:XVu0`(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .`)\GjDv  
public SiteFileFetch(SiteInfoBean bean) throws IOException .MXznz  
{
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siteInfoBean = bean; B<I%:SkF@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); c'vxT<8fWW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -*_D!  
if(tmpFile.exists ()) k>FMy#N|@  
{ +=)< Su.  
bFirst = false; \=kH7 !  
read_nPos(); T\{ on[O  
} *}-X '_  
else A{bt
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{ N)RyRR.x1.  
nStartPos = new long[bean.getNSplitter()]; _rR+u56y-  
nEndPos = new long[bean.getNSplitter()]; p&>*bF,  
} (vB ae
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} <%8j#@OdZ  
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public void run() j#f+0  
{ N/p9Ws  
//获得文件长度 2%m H  
//分割文件 &BY%<h0c  
//实例FileSplitterFetch V}. uF,>V  
//启动FileSplitterFetch线程 d(3F:dbk  
//等待子线程返回 X
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try{ =;W"Pi;*  
if(bFirst) .0:BgM  
{ rjo/-910  
nFileLength = getFileSize(); D^baXp8  
if(nFileLength == -1) .{1G"(z  
{ zH0%; o}  
System.err.println("File Length is not known!"); [ >O4hifq  
} 9z$]hl  
else if(nFileLength == -2) Z3g6?2w6  
{ "o2p|2c  
System.err.println("File is not access!"); GpMKOjVm|  
} o]t6u .L  
else HgvgO\`]  
{ ?l!L )!2  
for(int i=0;i<nStartPos.length;i++) ig4wwd@|  
{ %0fF
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); I?YT
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} ZR.1SA0x?O  
for(int i=0;i<nEndPos.length-1;i++) [^EU'lewnW  
{ w,bILv)  
nEndPos = nStartPos[i+1]; QM\vruTB  
} o@>{kzCx  
nEndPos[nEndPos.length-1] = nFileLength; / *RDy!m  
} 7g[m,48{  
} orVsMT[A  

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//启动子线程 |s-q+q{|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }__g\?Yf  
for(int i=0;i<nStartPos.length;i++) es]\xw  
{ +0rMv  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z4A a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q/m))!ikMt  
nStartPos,nEndPos,i); 7}OzTup  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %_0,z`f  
fileSplitterFetch.start(); k_/hgO  
} {_0Efc=7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WMnR+?q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S+py\z%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ] e!CH <N  
nEndPos = " + nFileLength); c9-$td&  
// fileSplitterFetch[nPos.length-1].start(); f{xR s-u]  
?v-IN  
7F;"=DarOE  
//等待子线程结束 ]:i :QiYD  
//int count = 0; i>HipD,TD  
//是否结束while循环 vo)
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boolean breakWhile = false; 4!p~Mr[E  
)^7Y^ue  
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while(!bStop) RIOR%~U  
{ 79U Th@r}  
write_nPos(); GenkYtS  
Utility.sleep(500); vpcHJ^19  
breakWhile = true; wUWSW<  
^"7tfo8  
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for(int i=0;i<nStartPos.length;i++) -ZFeE[Z  
{ ("0@_05OH  
if(!fileSplitterFetch.bDownOver) dya]^L}fL  
{ T=35?   
breakWhile = false; }ddwL  
break; xoF]r$sC8  
}
[SgWUP*  
} #qXE[%  
if(breakWhile) DnvJx!#R  
break; DE|r~TQ  
|};]^5s9  
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//count++; ";E Mu(IXb  
//if(count>4) &f'\9lO  
// siteStop(); i#$9>X  
} -FytkM^]6  
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System.err.println("文件下载结束！"); CnruaN@  
} rLs)
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catch(Exception e){e.printStackTrace ();} Y^m2ealC  
} Oe4 l` =2  
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//获得文件长度 CXks~b3SD  
public long getFileSize() g66=3c9</6  
{ ez=$]cln  
int nFileLength = -1; [?x9NQ{  
try{ -NtT@
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URL url = new URL(siteInfoBean.getSSiteURL()); [Av#Z)R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fN~kdm.  
httpConnection.setRequestProperty("User-Agent","NetFox"); Mnyg:y*=  
biG=4?Xl  
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int responseCode=httpConnection.getResponseCode(); zqfv|3-!}  
if(responseCode>=400) DrLNY"Zq  
{ []:;8fY  
processErrorCode(responseCode); $T{,3;kt  
return -2; //-2 represent access is error 
*6^|i}  
} e`k6YO  
fL.;-  
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String sHeader; zIt-mU  
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for(int i=1;;i++) ZOc1 vj  
{ Epj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J01w\#62pQ  
//Utility.log(in.readLine()); 3{RuR+yi  
sHeader=httpConnection.getHeaderFieldKey(i); J~KWn.  
if(sHeader!=null) NLFs)
6\  
{ GdG1e%y]z  
if(sHeader.equals("Content-Length")) PxzeN
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{ (RG\U[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); s<gZB:~  
break; kK&tB  
} 7Ipt~K}  
} E*ybf'  
else \]GO*]CaV  
break; B!GpD@U  
} F{)YdqQ  
} v1<gNb)`  
catch(IOException e){e.printStackTrace ();} _6"vPN  
catch(Exception e){e.printStackTrace ();} {PgB
~|W  
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Utility.log(nFileLength); :zfnp,Gv  
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return nFileLength; ]#R'hL%f  
} ?g|K"P<1  
:J]S+tQ)  
WsRG>w3"  
//保存下载信息（文件指针位置） =Xze).g  
private void write_nPos() 44FK%TmtF  
{ "6_#APoP  
try{ fgg^B[(Y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9
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output.writeInt(nStartPos.length); E9pKR+P  
for(int i=0;i<nStartPos.length;i++) O$
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{ - {<`Z  
// output.writeLong(nPos); !O F#4N  
output.writeLong(fileSplitterFetch.nStartPos); \DBoe:0~  
output.writeLong(fileSplitterFetch.nEndPos); 5MV4N
[;  
} _d6mf
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output.close(); }MP2)6  
} FP<RoA?W  
catch(IOException e){e.printStackTrace ();} $l-|abLELz  
catch(Exception e){e.printStackTrace ();} f gI.q  
} P`6 T;|VDk  
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//读取保存的下载信息（文件指针位置） h Vz%{R"  
private void read_nPos() #<f}.P.Uc  
{ yveyAsN`B  
try{ Yf.H$L  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); uW%7X2K  
int nCount = input.readInt(); MuB8gSu  
nStartPos = new long[nCount]; 3
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nEndPos = new long[nCount]; ~ z4T   
for(int i=0;i<nStartPos.length;i++) v:1l2Y)g  
{ mNN,}nHu  
nStartPos = input.readLong(); ZiM#g1;  
nEndPos = input.readLong(); AE!WYE  
} '7o
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input.close(); #@H{Ypn`  
} %Y%+K5;AZ  
catch(IOException e){e.printStackTrace ();} }u cqzdk#2  
catch(Exception e){e.printStackTrace ();} 4 q
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} 1<A+.W  
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)?~3fb6^  
private void processErrorCode(int nErrorCode) YS=|y}Q|7d  
{ sN|-V+7&j  
System.err.println("Error Code : " + nErrorCode); >C"cv^%c  
} ;OQ-T+(T  
9(lIz{  
lz\{ X  
//停止文件下载 !jY/}M~F1  
public void siteStop() +4\JY"oi  
{ SFoF]U09
 
bStop = true; vM~/|)^0sW  
for(int i=0;i<nStartPos.length;i++) i0/gyK  
fileSplitterFetch.splitterStop(); RtH[OZu(8  
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8~RUYsg  
} ]W<E#^  
} I=D{(%+^d  
//负责部分文件的抓取 Na: M1Uhb  
**FileSplitterFetch.java 6nt$o)[  
*/ 6yk  
package NetFox; St,IWOmq"  
8B;`9?CI  
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import java.io.*; (ii 5pnq  
import java.net.*; }#zE`IT  
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public class FileSplitterFetch extends Thread { B) &BqZ&  
u~<>jAy  
HP|,AmVLl  
String sURL; //File URL =sRd5aMs  
long nStartPos; //File Snippet Start Position I
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long nEndPos; //File Snippet End Position E#Ynn6  
int nThreadID; //Thread's ID i_g="^
 
boolean bDownOver = false; //Downing is over S$W *i@x?  
boolean bStop = false; //Stop identical RL~|Kr<7J  
FileAccessI fileAccessI = null; //File Access interface #W 1`vke3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException deaxb8'7  
{ .6!]RA5!=  
this.sURL = sURL; J&^r}6D  
this.nStartPos = nStart; :eS7"EG{3  
this.nEndPos = nEnd; \F,?ptu  
nThreadID = id; ;1S{xd*^N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &k\
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} z QoMHFL3  
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. )Fn]x"<  
public void run() H:U1#bQQ:  
{ ;G!X?(%+  
while(nStartPos < nEndPos && !bStop) SynxMUlA  
{ l1jS2O(  
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try{ l*_b)&CH  
URL url = new URL(sURL); `@ qSDW!b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )ty *_@N0  
httpConnection.setRequestProperty("User-Agent","NetFox"); IK{0Y#c  
String sProperty = "bytes="+nStartPos+"-"; /.'1i4Xa1P  
httpConnection.setRequestProperty("RANGE",sProperty); \yb^%$hZ0  
Utility.log(sProperty); ~J)4(411  
GY,@jp|R  
sC ]&Qr_  
InputStream input = httpConnection.getInputStream(); F"hi2@/TI  
//logResponseHead(httpConnection); [KWF7GQi  
)%;#~\A  
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byte[] b = new byte[1024]; {x
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int nRead; wX#\\Jgi  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9foQ0#R  
{ g%j z,|  
nStartPos += fileAccessI.write(b,0,nRead); s`C#=l4  
//if(nThreadID == 1) f:7Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ++,m
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} -2> L*"^  
Uo^s]H#:  
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Utility.log("Thread " + nThreadID + " is over!"); G2a fHL<  
bDownOver = true; Iay7Fkv  
//nPos = fileAccessI.write (b,0,nRead); ,-] JCcH  
} :KX/`   
catch(Exception e){e.printStackTrace ();} XIBw&mWf  
}  Ea\a:  
} W7(OrA!  
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}C"#b\A2  
//打印回应的头信息 ct~lt'L\  
public void logResponseHead(HttpURLConnection con) )yJeh  
{
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for(int i=1;;i++) b${Kj3(  
{ 1}[\@n+b  
String header=con.getHeaderFieldKey(i); b4%IyJr  
if(header!=null) Syp|s3u;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); h^hEyrJw  
Utility.log(header+" : "+con.getHeaderField(header)); wk9tJ#}  
else +Ya-h~7;g#  
break;  C&e
  
} %Pa-fee  
} `9K'I-hv<8  
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public void splitterStop() Y#]Y$n  
{ W:rzfO.`Z  
bStop = true; DT9i<kl  
} C 2oll-kN  
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} #Q'i/|g
 
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/* y]?$zbB  
**FileAccess.java "g=ux^+X\  
*//文件访问(定位，写) n1sH`C[c  
package NetFox; `=-}S+  
import java.io.*; $S,
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@~63%6r#4M  
zLxWyPM0;  
public class FileAccessI implements Serializable{ ?erDP8  
2lp.Td`{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HNh=ig
u  
RandomAccessFile oSavedFile; ;quGy3  
long nPos; 3ZZJYf=  
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public FileAccessI() throws IOException `J-"S<c?_  
{ ' >\*  
this("",0); n53}79Uiz  
} aY {.  
m   
*JpEBtTv=5  
public FileAccessI(String sName,long nPos) throws IOException #;mZ3[+i5  
{ YF:NRY[i  
oSavedFile = new RandomAccessFile(sName,"rw"); )bK<t  
this.nPos = nPos; Sl$dXB@  
oSavedFile.seek(nPos); pp{);  
} U-lN_?  
uq 6T|Zm  
T.1z<l""  
public synchronized int write(byte[] b,int nStart,int nLen) 6=')*_~/  
{ 4a3f!G$  
int n = -1; M1ayAXO  
try{ sdO;vp^
:b  
oSavedFile.write(b,nStart,nLen); 6iC}%eU  
n = nLen; 2j"%}&  
} r{<u\>6X>P  
catch(IOException e) #%{\59/w  
{ 3Q;^X(Ml*  
e.printStackTrace (); G2jEwi  
} 71)#'ey  
t]@Zd*  
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return n; lN1zfM  
} uY;/3?k&  
/kJ*WA?J  
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} VJ$C)0xQA  
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/* lo(Ht=d  
**SiteInfoBean.java Fza)dJ7  
*/ @Td[rHl  
package NetFox; l+N?:E$5=%  
PO}Q8Q3  
h:GOcLYM@X  
public class SiteInfoBean { @O3
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w_{z"VeD  
7}lZa~/  
private String sSiteURL; //Site's URL NMj`wQ`M+  
private String sFilePath; //Saved File's Path HOUyB's'  
private String sFileName; //Saved File's Name /f6]XP\'`+  
private int nSplitter; //Count of Splited Downloading File 4kz8U  
|Ji?p>\~  
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public SiteInfoBean() _Ng*K]0/E  
{//nSplitter的缺省值为5 rxz3Mqg  
//default value of nSplitter is 5 ad~ qr n\  
this("","","",5); GqAedz;.  
} F9c2JBOM  
xH f9N?  
sEj:%`l|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7<tqT @c  
{ b\+|g9Tm  
sSiteURL= sURL; cj8r-Vu/N  
sFilePath = sPath; lLJb3[ e.  
sFileName = sName; XWvs~Xw@  
this.nSplitter = nSpiltter; KXM-GIRUG  
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Lhc@*
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} <.' cCY  
J`8>QMK^5  
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public String getSSiteURL() @t2 Q5c  
{ P0Jd6"sS"  
return sSiteURL; $x)'_o}e  
} .ClCP?HG  
*.+>ur?t  
-'0AV,{Z  
public void setSSiteURL(String value) Mu(Y6  
{ {xykf7zp  
sSiteURL = value; 'w!gQ#De  
} h1kPsgzR  
|l?ALP_g  
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public String getSFilePath() SB'YV#--  
{ ,mX|TI<*  
return sFilePath; A8RT3OiXA  
} (gf\VYM-7  
f|G7L5-  
KGWENX_U  
public void setSFilePath(String value) q%'ovX(dm  
{ 395o[YZx*  
sFilePath = value; $ i&$ZdX  
} 5]Ra?
rF  
`MwQ6%lf  
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public String getSFileName() R] [M_ r  
{ hHg gH4T  
return sFileName; &59#$LyH`%  
} 6nfkZvn  

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public void setSFileName(String value) 4GfLS.Ip  
{ /SKr.S61e  
sFileName = value; 'f}S,i +q  
} ]p*) PpIl  
:fYwFD( 9  
6uXW`/lvX  
public int getNSplitter() 0oJ^a^|  
{ iy#OmI>j  
return nSplitter; YJ^ lM\/<  
} h]MVFn{  
-5cH$]1\  
cMWO_$  
public void setNSplitter(int nCount) qQcC[50  
{ bZ9NnSuH  
nSplitter = nCount; F=om^6G%X5  
} 5Hm!
5:ZB  
} 9aU:[]w   
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/* Q kZM(pG  
**Utility.java eE{L>u  
*/ :.Q
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package NetFox; i@CMPz-h&  
; BZM~'  
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public class Utility { D,n}Qf!GYk  
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?R]y}6P$  
public Utility() ye|a#a9N  
{ oyt//SE  
{~^)-^Wt:  
G; [AQ:Iy  
} UBi4itGD  
VqL 5f  
//线程睡眠 6)U&XWH0
 
public static void sleep(int nSecond) {g- DM}q  
{ 9xQ8`7  
try{ 4LEE /  
Thread.sleep(nSecond); NN 6KLbC(  
} :2pBv#\"qk  
catch(Exception e) o1WidJ"  
{ yOK])&c  
e.printStackTrace (); SO<m(o)G2  
} l>UUaf|O  
} GeaDaYh#T  
0Mu8ZVI{  
//日志 o$ce1LO?|N  
public static void log(String sMsg) KF_Wu}q d  
{ klJ[ {p  
System.err.println(sMsg); F!&pENQ  
} 2]3HX3  
~Ex.
Yp8.  

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public static void log(int sMsg) b!X
"2'  
{ EOX_[ek7  
System.err.println(sMsg); 06^1#M$'  
} j 3MciQ`  
} nbASpa(  
Dum`o^l#  
bfJ`}xl
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/* 6rQpK&Jx  
**TestMethod.java v$m[#&O^V?  
*/ 0BCGJFZ{  
package NetFox; OJsd[l3xR  
m6r )Z5}f  
XLmMK{
gs  
public class TestMethod { o~x39  
~'2r&?=\  
bkwa{V  
public TestMethod() .W :  
{ ///xx/weblogic60b2_win.exe LBkcs4+  
try{ q Iy^N:C2'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A3$aMCwKd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8F^,8kIR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RF5q5<0  
fileFetch.start(); |R;l5ZKvV  
} E,LYS"%_  
catch(Exception e){e.printStackTrace ();} F[kW:-ne@Z  
zZ9<4"CIk  
9*|3E"Vr  
} %md^S |  
V 7l{hEo3?  
}11`98>B6:  
public static void main(String[] args) %i&/$0.8  
{ ^
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new TestMethod(); 6%kJDY.  
} S&3X~jD(1  
} (~Uel1~@  
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