http断点续传简单实现（java)

/* UF0W%Z  
**SiteFileFetch.java a\;1%2a  
*/ Rah"La  
package NetFox; Cuu yG8  
import java.io.*; d` %8qLIW  
import java.net.*; ^0)Mc"&{  
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a~q_2S]h  
public class SiteFileFetch extends Thread { nGQc;p5;  
8,B?!%FP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean t"x 8]Gy  
long[] nStartPos; //开始位置 p4mi\~Q  
long[] nEndPos; //结束位置 4wYD-MB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 l r80RL'_  
long nFileLength; //文件长度 .1n=&d|  
boolean bFirst = true; //是否第一次取文件 701a%Jq_2  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 ).U\,@[A{  
DataOutputStream output; //输出到文件的输出流 ^j]"!:h  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jz,Mm,Gi  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7k,pUC-w7c  
{ ,;;7+|`  
siteInfoBean = bean; NwAvxN<R(f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jf&B5>-x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e_RLKFv7  
if(tmpFile.exists ()) \9"  
{ <A|X4;  
bFirst = false; YnM&t ;TX  
read_nPos(); w-iu/|}  
} < z':_,  
else & -r^Q  
{ krqz;q-p~  
nStartPos = new long[bean.getNSplitter()]; S!+c1q: ].  
nEndPos = new long[bean.getNSplitter()]; r-^FM~
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} Lx%*IE|c
 
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} jfmHc(fX4  
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public void run() I=aoP}_  
{ 6/-]  
//获得文件长度 (rKyX:Vsy  
//分割文件 {!RDb'Zp  
//实例FileSplitterFetch J?6.yL;  
//启动FileSplitterFetch线程 7Qdf#DG  
//等待子线程返回 U ?iw  
try{ %MG{KG=&o  
if(bFirst) E_q/*}]pE  
{ `wI$  
nFileLength = getFileSize(); jej.!f:H  
if(nFileLength == -1)
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{ YnR8mVo5Q  
System.err.println("File Length is not known!"); UY>[  
} ^}SP,lg'  
else if(nFileLength == -2) 4X-"yQ<U  
{ CdBpz/  
System.err.println("File is not access!"); Vz.G!*>Dg  
} _V2^0CZ  
else Eep~3U  
{ %x'}aTa  
for(int i=0;i<nStartPos.length;i++) m:}PVJ-"  
{ 7eNLs  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); mM9aT0_w  
} [^Z)f<l  
for(int i=0;i<nEndPos.length-1;i++) VSx9aVPkC  
{ 5!QT }Um  
nEndPos = nStartPos[i+1]; yv[3&E?  
} '/OcJVSR  
nEndPos[nEndPos.length-1] = nFileLength; @h&:xA56  
} epicY  
} m+UWvUB)  
G2$<Q+UYs?  
jz,K>   
//启动子线程 _0cCTQE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A<h^.{  
for(int i=0;i<nStartPos.length;i++) O2pntKI  
{ "D\>oFu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), --fRhN>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1d$qr`  
nStartPos,nEndPos,i); ?"F9~vx&G  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ol0i^d*9F  
fileSplitterFetch.start(); ^ps6\>=0cW  
} @4t_cxmD  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7vo8lnQ{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4,,DA2^!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", QdIx@[+WOq  
nEndPos = " + nFileLength); _sb~eB~<(  
// fileSplitterFetch[nPos.length-1].start(); i:a*6b.U@N  
-Oi8]Xw^@y  
@T"-%L8PL  
//等待子线程结束 ! k[JP+;  
//int count = 0; *{_N*p\{  
//是否结束while循环 Pz^C3h$5_  
boolean breakWhile = false; b(IZ
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while(!bStop) T_)g/,5>  
{ {|d28!8w  
write_nPos(); M(^_/1Z  
Utility.sleep(500);
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breakWhile = true; F?z:[1(:  
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for(int i=0;i<nStartPos.length;i++) ~6"=d  
{ {q/;G!ON.S  
if(!fileSplitterFetch.bDownOver) $`A{-0=x\U  
{ l4gF.-.GYF  
breakWhile = false; 4#Xz-5v  
break; !/a![Ne  
} vbD""  
} _Sg"|g  
if(breakWhile) gSa!zQN6  
break;
{/FdrS  
J9*i`8kU.  
Z%Pv,h'Q  
//count++; qyBC1an5,  
//if(count>4) 'fs tfk  
// siteStop(); %[4u #G`  
}  >akC  
4tEAi4H|`@  
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System.err.println("文件下载结束！"); F pT$D  
} fikDpR  
catch(Exception e){e.printStackTrace ();} 4]HW!J  
} LOgFi%!6:  
d5>
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//获得文件长度 }S$
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public long getFileSize() YV8PybThc  
{ 7KHQ0  
int nFileLength = -1; \@Gcx}Y8h  
try{ MK-+[K  
URL url = new URL(siteInfoBean.getSSiteURL()); !|W.YbS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eslv
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httpConnection.setRequestProperty("User-Agent","NetFox"); ]v/pMg#-  
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int responseCode=httpConnection.getResponseCode(); C hQ] d  
if(responseCode>=400) nQOzKw<j%  
{ TI}a$I*  
processErrorCode(responseCode); MgP&9  
return -2; //-2 represent access is error :?}mu1  
} d A'0'M  
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String sHeader; ymp ik.'  
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for(int i=1;;i++) ?@z/#3b  
{ aX~Jk >a0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V.9p4k`  
//Utility.log(in.readLine()); 7|o!v);uR  
sHeader=httpConnection.getHeaderFieldKey(i); k*u6'IKi.4  
if(sHeader!=null) \#PZZ
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{ .EPv4[2%F8  
if(sHeader.equals("Content-Length")) Qqi?DW1)-  
{ b9ud8wLE[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Uqz.Q\A  
break; QI'-I\Co  
} )@p?4XsT4J  
} .R@s6}C`}=  
else Q_Br{ `c  
break; M KX+'p\w  
} kdWUz(  
} <$@I*xk[  
catch(IOException e){e.printStackTrace ();} ,N_/J4Us  
catch(Exception e){e.printStackTrace ();} 734t  
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Utility.log(nFileLength); Y]=k"]:%  
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return nFileLength; : h(Z\D_  
} F\hVunPVx  
6yBd9=3K  
c3Gy1#f:#2  
//保存下载信息（文件指针位置） pH2/."zE<  
private void write_nPos() }a/z.&x]V  
{ tot~\S  
try{ 6uv~.-T<l  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QFnpp\K  
output.writeInt(nStartPos.length); +*w}H 0Z  
for(int i=0;i<nStartPos.length;i++) )7]yzc  
{ SuB8mPn  
// output.writeLong(nPos); gTgoS:M"_O  
output.writeLong(fileSplitterFetch.nStartPos); +I-BqA9  
output.writeLong(fileSplitterFetch.nEndPos); kh{3s:RQfC  
} C=|8C70[%N  
output.close(); ok [_Z;  
} yf;TIh%)=  
catch(IOException e){e.printStackTrace ();} ]v0Z[l>yf  
catch(Exception e){e.printStackTrace ();} _g f
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} V%)Tu{L  
S*>T%#F6Uo  
Kj
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//读取保存的下载信息（文件指针位置） +zd/<  
private void read_nPos() j>e RV ol  
{ kMK0|+  
try{ SB08-G2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); o<iU;15  
int nCount = input.readInt();
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nStartPos = new long[nCount]; P;@j  
nEndPos = new long[nCount]; G
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for(int i=0;i<nStartPos.length;i++) $+f=l~/s  
{ x;sc?5_`  
nStartPos = input.readLong(); {;E
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nEndPos = input.readLong(); A^p{Cq@E  
} 9gdK&/ulR  
input.close(); |:&O!36  
} y.I&x#(^  
catch(IOException e){e.printStackTrace ();} f1v4h[)-
  
catch(Exception e){e.printStackTrace ();} V@T(%6<|  
} v-SXPL]_^  
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#  
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private void processErrorCode(int nErrorCode) cC>Svf[CzK  
{ e8T"d%f?  
System.err.println("Error Code : " + nErrorCode); c|`$ h  
} }IZw6KiN  
*Ow2,{Nn  
W;cYg.W2  
//停止文件下载 79cM_O  
public void siteStop() Ncsh{.
  
{ {l5fKVb\C  
bStop = true; <xF]ca  
for(int i=0;i<nStartPos.length;i++) },#7  
fileSplitterFetch.splitterStop(); Y)]C.V,~  
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+
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} M2w'cdHk  
} 9&uf
  
//负责部分文件的抓取 Dw7Xy}I/  
**FileSplitterFetch.java \>pm (gF  
*/ '2i !RT-  
package NetFox; ^9Cu?!xu0  
q^sZP\i,*;  
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import java.io.*; "OK[uug  
import java.net.*; ypG*41  
a*LfT<hmU3  
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public class FileSplitterFetch extends Thread { s2NBYDi$?  
c?EvrtND  
7(X z%v  
String sURL; //File URL GM'yOJo  
long nStartPos; //File Snippet Start Position '7PaJj=Nx  
long nEndPos; //File Snippet End Position G"E_4YkJ  
int nThreadID; //Thread's ID s[y.gR.(  
boolean bDownOver = false; //Downing is over !&hqj
$>-}  
boolean bStop = false; //Stop identical {QylNC
9  
FileAccessI fileAccessI = null; //File Access interface mB"I(>q*M  
{ri={p]l  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tE{M  
{ e2NK7  
this.sURL = sURL; d6'G 7'9  
this.nStartPos = nStart; pvUV5^B(M  
this.nEndPos = nEnd; %b<W]HwA  
nThreadID = id; _p%n%Oce
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2vLun
  
} 72"H#dy%U  
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public void run() 5|*`} ;/y  
{ \>Rfa+  
while(nStartPos < nEndPos && !bStop) |k90
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{ -5 PVWL\  
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try{ 0V>HoH  
URL url = new URL(sURL); 5!fYTo|G>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r>F
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httpConnection.setRequestProperty("User-Agent","NetFox"); |,:p[Oy  
String sProperty = "bytes="+nStartPos+"-"; ]S[/a  
httpConnection.setRequestProperty("RANGE",sProperty); .
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Utility.log(sProperty);
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6V]m0{:E  
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InputStream input = httpConnection.getInputStream(); zA>X+JH>iw  
//logResponseHead(httpConnection); !|xB>d q?  
QJ4$) Fr(  
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byte[] b = new byte[1024]; {~&Q"8 }G  
int nRead; {~F|"v  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "4H@&:-(p  
{ ll4CF}k  
nStartPos += fileAccessI.write(b,0,nRead); @QVg5  
//if(nThreadID == 1) rf%lhBv  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Rh|9F yN  
} C'|9nK$%  
-Q@f),  
C&H'?0Y@  
Utility.log("Thread " + nThreadID + " is over!"); Fy Ih\  
bDownOver = true; .cQO?UKK  
//nPos = fileAccessI.write (b,0,nRead); G/Sp/I<d  
} JOY&YA$U  
catch(Exception e){e.printStackTrace ();} U?:P7YWy  
}
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} HS{Vohy>  
N=<`|I  
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//打印回应的头信息 |*NZ^6`@  
public void logResponseHead(HttpURLConnection con) )/>BgXwH  
{ [M~tH *4"  
for(int i=1;;i++) O%\cRn8m  
{ zvdut ,6<  
String header=con.getHeaderFieldKey(i); "4\  
if(header!=null) 7[;!enO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {sC Ni  
Utility.log(header+" : "+con.getHeaderField(header)); b~,e(D9DG  
else 196a~xNV  
break; d'ZNp2L  
} }`<&l  
} F/5G~17  
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public void splitterStop() .5G`Y  
{ jjj<B
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bStop = true; ;(/go\m tB  
} N,Ma\D+^t  
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} 0d_)C>gcF  
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/* 'l.tV7  
**FileAccess.java O68-G   
*//文件访问(定位，写) JpfA+r  
package NetFox; >[;@ [4}  
import java.io.*; 5;0w({1l  
B-C$>H^  
-|m3=#  
public class FileAccessI implements Serializable{ S"h;u=5it  
}b(hD|e  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Th9V8Rg+E  
RandomAccessFile oSavedFile; uH9Vj<E$K  
long nPos; Yn~fnI{  
FFcCoPX_  
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public FileAccessI() throws IOException 5 qfvHQ ~M  
{ imYfRi=$  
this("",0); H<_Tn$<zH.  
} 3s!6rT_=)d  
k=mQG~  
bu _ @>`S  
public FileAccessI(String sName,long nPos) throws IOException E#,"C`&*  
{ s0?'mC+p  
oSavedFile = new RandomAccessFile(sName,"rw"); Qt+D ,X  
this.nPos = nPos; larv6ncV  
oSavedFile.seek(nPos); 7_1 Iadb  
} )-3~^Y#r_  
t`K9K"|k  
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public synchronized int write(byte[] b,int nStart,int nLen)  pRobx  
{ L K#A  
int n = -1; o7!A(Eu  
try{ _k2R^/9Ct%  
oSavedFile.write(b,nStart,nLen); QAV6{QShj  
n = nLen; 2O=$[b3  
} kT@ITA22  
catch(IOException e) dA hcA.  
{ $k\bP9  
e.printStackTrace (); vTK%8qoZ  
} 6LDZ|K@  
a20w.6F  
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return n; gFTU9k<  
} lKejWT`;  
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vMp=\U-~^  
} M
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3HrG^/  
7p.8{zQ*  
/* }U_^zQfaj  
**SiteInfoBean.java 7#E/Q~]'6  
*/ Z{^!z  
package NetFox; s9wzN6re  
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MF"*xr v  
public class SiteInfoBean { S5hc@^|0Z  
Wa^Wn +r  
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private String sSiteURL; //Site's URL 3%)cUkD  
private String sFilePath; //Saved File's Path `VwG]2 I  
private String sFileName; //Saved File's Name :g|.x
  
private int nSplitter; //Count of Splited Downloading File F-3=eKZ  
*1dZs~_  
W8g13oAu"  
public SiteInfoBean() }'P|A  
{//nSplitter的缺省值为5 uBww  
//default value of nSplitter is 5 4~Cf_`X}]  
this("","","",5); ([q>.[WbH]  
} V4Rs  
{ }/  
#-B<u-  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %6cr4}Zm}  
{ `C>h]H(  
sSiteURL= sURL; pqO3(2F9
 
sFilePath = sPath; bDvGFSAH  
sFileName = sName;
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this.nSplitter = nSpiltter; d8: $ll  
Wm
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} 2@a'n@-  
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DIGw4g4Kt  
public String getSSiteURL() 6Mc&=}bV  
{ k5\V:P=#  
return sSiteURL; fh =R  
} .$-;`&0cZ  
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public void setSSiteURL(String value) [1(eSH  
{ ti+e U$  
sSiteURL = value; c
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} m%J?5rR3  
'QE8  
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public String getSFilePath() I '0
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{ *x8~}/[T(F  
return sFilePath; ZiR}S  
} G
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|gA@$1+}  
9q?knMt  
public void setSFilePath(String value) 5]*lH t  
{ 8x1!15Wiz  
sFilePath = value; &pI\VIx ?  
} 9mvy+XD  
jW#dUKS(  
i%133in  
public String getSFileName() L?u{vX  
{ \)28,`  
return sFileName; auN
8M.  
} yam'LF  
Qf0P"s`  
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public void setSFileName(String value) ^kNVQJiZyG  
{ =Jl\^u%H(x  
sFileName = value; [UkcG9  
} nycJZ}f:wP  
jF6Q:`k  
AT t.}-  
public int getNSplitter() Z%o.kd"  
{ %GjG.11V,_  
return nSplitter; Aa1#Ew<r  
} 9Y2u/|!.3  
; ]%fFcy  
9*iVv)jd  
public void setNSplitter(int nCount) 1N _"Mm{  
{ [uqr  
nSplitter = nCount; }%wP^6G*x\  
} ^e "4@O"  
} ,eebO~7vB  
\|X 1  
[x>Pf1  
/* %+/v")8+?  
**Utility.java Qq{t
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*/ wa[J\lW  
package NetFox; N/-(~r[
  
CPa+?__B  
gm]q<~eMW  
public class Utility { ?z)
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\Yp"D7:Qi  
t#M[w|5?  
public Utility() ';.TQ_I7Y  
{ hK4ww"-  
=:T"naY(  
P `<TO   
} u@Gum|_=N
 
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//线程睡眠 zk70D_}L  
public static void sleep(int nSecond) :fX61S6)  
{ ce4rhtkV  
try{ q@1A2L\Om  
Thread.sleep(nSecond); .))k
  
} M97+YMY)  
catch(Exception e) 49/2E@G4.  
{ aEQrBs  
e.printStackTrace (); dG3?(}p+  
} w2 (}pz:  
} unYPvrd  
U#Kw+slM  
//日志 :1'1
n  
public static void log(String sMsg) *>iJ=H  
{ M2:3k  
System.err.println(sMsg); l+(B~v  
} 4cm~oZ  
:'
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\py&v5J)s!  
public static void log(int sMsg) N<(rP1)`v  
{ Y,n8co^  
System.err.println(sMsg); LfnQcI$kO  
} /;TD n>lq  
} %LdBO1D0  
VKXB)-'L  
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/* HE4S%#bH>  
**TestMethod.java `T2DGv  
*/ <6N3()A)%1  
package NetFox; Q\~#cLJ/  
7}=MVp] )S  
/$8& r  
public class TestMethod { UQ e1rf  
GYT0zMMf  
y#ON=8l  
public TestMethod() _n*gj-  
{ ///xx/weblogic60b2_win.exe '+|uv7|+v  
try{ <+ <o X"I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /KiaLS  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +ZwTi!W  
SiteFileFetch fileFetch = new SiteFileFetch(bean); UA0R)BH'  
fileFetch.start(); Dxr4B<  
} q<g!bW%  
catch(Exception e){e.printStackTrace ();} \>/AF<2"  
~8Ef`zL  
Y% [H:  
} &6Wim<*  
jN+2+P%OL  
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public static void main(String[] args) \bSakh71  
{ H/#WpRg  
new TestMethod(); fK4O N'[R:  
} Xp|$z~  
} Df$Yn  
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