http断点续传简单实现（java)

/* |g$n-t  
**SiteFileFetch.java /.1yxb#Z?,  
*/ >!D^F]CH  
package NetFox; 5 $vUdDTg  
import java.io.*; 6SJryf~w  
import java.net.*; @(m+B\  
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public class SiteFileFetch extends Thread { KE~l#=S  
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SiteInfoBean siteInfoBean = null; //文件信息Bean I:L}7uA[t  
long[] nStartPos; //开始位置 ma gZmY~  
long[] nEndPos; //结束位置 [f1'Qb  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Fv<^\q  
long nFileLength; //文件长度 Fx3CY W  
boolean bFirst = true; //是否第一次取文件 e#5LBSP  
boolean bStop = false; //停止标志 'o!{YLJ fM  
File tmpFile; //文件下载的临时信息 _x2i=SFo*$  
DataOutputStream output; //输出到文件的输出流 Mur)'  
L/[b~D>T%  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9i=HZ\s3  
public SiteFileFetch(SiteInfoBean bean) throws IOException (/^s?`1{N?  
{ ZNKopA(=|%  
siteInfoBean = bean; ]SO-NR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ik\n/EE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); P,eP>55'K  
if(tmpFile.exists ()) ^?
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{ xnR;#Yc  
bFirst = false; y37c&XYq  
read_nPos(); NKSK+ll2  
} ;UAi>//#   
else Qvx[F:#Tk  
{ UGb<&)  
nStartPos = new long[bean.getNSplitter()]; YcmLc)a7  
nEndPos = new long[bean.getNSplitter()]; 1Mtm?3Pt  
} AW R  
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} sU=7)*$  
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public void run() \se /2l  
{ #
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//获得文件长度 Fmd^9K  
//分割文件 (*K=&e0O  
//实例FileSplitterFetch ?
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//启动FileSplitterFetch线程 MB!_G[R  
//等待子线程返回 n9w(Z=D\  
try{ na4^>:r~  
if(bFirst) V#P`FX  
{ eVetG,["  
nFileLength = getFileSize(); 'Zket=Sm;  
if(nFileLength == -1) r3BQo[ 't  
{
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System.err.println("File Length is not known!"); ,O'#7Dj  
} 0#d:<+4D  
else if(nFileLength == -2) l(<=JUO;  
{ (>R  
System.err.println("File is not access!"); h3`\L4b  
} =>LQW;Sjz  
else E5+-N  
{ j(>~:9I`  
for(int i=0;i<nStartPos.length;i++) _no;B_m~  
{ !!\x]
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8{f~tPY  
} _-R&A@  
for(int i=0;i<nEndPos.length-1;i++)
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{ b;5&V_  
nEndPos = nStartPos[i+1]; 6]^~yby P  
} QB"Tlw(  
nEndPos[nEndPos.length-1] = nFileLength; 0|=
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} `mE>h4  
} 7/969h^s  
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//启动子线程 ,s~d39{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; itn<c2UyA  
for(int i=0;i<nStartPos.length;i++) 49Q tfk  
{ q(9S4F   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +td]g9Ie  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 51Q m2,P1^  
nStartPos,nEndPos,i); Q|7$SS6$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Zn{Y+ce7d  
fileSplitterFetch.start(); {u(( y D  
} @r*
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8-u #<D.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); B4MrrW4=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", UID0|+%Y  
nEndPos = " + nFileLength); lvd`_+P$  
// fileSplitterFetch[nPos.length-1].start(); {y%cTuC=  
'5r\o8RjN  
^B!cL~S*I  
//等待子线程结束 l8~s#:v6X  
//int count = 0; %Ek!3t  
//是否结束while循环 QnTKo&|9  
boolean breakWhile = false; 4Nl3"@<$  
"sUjJ|
 
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while(!bStop) wsEOcaie  
{ &`%J1[dy  
write_nPos(); bn#'o(Lp  
Utility.sleep(500); sJ{J@/5  
breakWhile = true; \n>7T*iM&  
F^Y%Q(Dd7w  
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for(int i=0;i<nStartPos.length;i++) kQw%Wpuq[/  
{ V~ q b2$  
if(!fileSplitterFetch.bDownOver) [e f&|Pi-  
{ ^iqy|zNtn  
breakWhile = false; |*%i]@V=  
break; \#sdN#e;XA  
} bamQ]>0|>!  
} _zK ~9/5  
if(breakWhile) P\ia ?9  
break; ]RxJ^'a63  
qHl>d*IZ  
r]=Z :  
//count++; =oT4!OUf  
//if(count>4) q
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// siteStop(); ^e{]WH
?  
}
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System.err.println("文件下载结束！"); ZKTY1JW_  
} 8.zYa(<2  
catch(Exception e){e.printStackTrace ();} :ggXVwpe  
} .(%]RSBY  
cb5T-'hY  
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//获得文件长度 tNG[|Bi#  
public long getFileSize() BIXbdo5F  
{ O<P(
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int nFileLength = -1; W+I""I*mV  
try{ bk|?>yd  
URL url = new URL(siteInfoBean.getSSiteURL()); ^O QeOTF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0WSOA[R%[b  
httpConnection.setRequestProperty("User-Agent","NetFox"); L_Xbca=  
A=+1PgL66  
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int responseCode=httpConnection.getResponseCode(); 6&;h+;h  
if(responseCode>=400) D!V~g72j  
{ *|as-!${k  
processErrorCode(responseCode); <8ih >s(C  
return -2; //-2 represent access is error U'LPaf$O  
} RqKkB8g  
i<{:J -U|  
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String sHeader; Q%:Z&lgy  
%uz6iQaq]X  
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for(int i=1;;i++) NXMZTZpB7  
{ (tCBbPW6T?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); zSagsH |W  
//Utility.log(in.readLine()); 2 b80b50  
sHeader=httpConnection.getHeaderFieldKey(i); %)w7t[A2D  
if(sHeader!=null) :7?n)=Tx  
{ H5(:1  
if(sHeader.equals("Content-Length")) ](^FGz  
{ zm mkmTp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }ag;yf;  
break; Gc_KS'K@$  
} uN=f(-"  
} vty:@?3\  
else .cz7jD  
break; wpD}#LRfm  
} eExI3"|Q  
} x^Zm:Jrw~  
catch(IOException e){e.printStackTrace ();}  s&iu+>  
catch(Exception e){e.printStackTrace ();} kkIG{Bw  
x~ID[  
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Utility.log(nFileLength); <m,bP c :R  
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return nFileLength; p_i',5H(  
} QJSi|&Rx&?  
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.I]EP-  
//保存下载信息（文件指针位置） %<|cWYM="z  
private void write_nPos() 32Wa{LG;2  
{ 7NkMr8[}F  
try{ B r6tgoA  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <tW/9}@p9  
output.writeInt(nStartPos.length); sB!6"D5
 
for(int i=0;i<nStartPos.length;i++) C@g/{?\  
{ q|
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// output.writeLong(nPos); ]*D~>q"#\  
output.writeLong(fileSplitterFetch.nStartPos); G!Yt.M0  
output.writeLong(fileSplitterFetch.nEndPos); M5
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} 81!gp7c  
output.close(); +LlAGg]Z  
} <Y"HCa{  
catch(IOException e){e.printStackTrace ();} U,8mYv2|  
catch(Exception e){e.printStackTrace ();} :1;"{=Yx}  
} 6]mAtA`Y  
|Yv,zEY)  
l=L(pS3 ~  
//读取保存的下载信息（文件指针位置） F_&H*kL L3  
private void read_nPos() )d>Dcne  
{ @ V_i%=go  
try{ |d,bo/:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); n(.L=VuXn  
int nCount = input.readInt(); U,lO{J
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nStartPos = new long[nCount]; +1r><do;  
nEndPos = new long[nCount]; TAq[g|N-;  
for(int i=0;i<nStartPos.length;i++) B%5"B} nG  
{ `~D{]'j  
nStartPos = input.readLong(); 2Z?l,M~
  
nEndPos = input.readLong(); \}AJ)v*<  
} $wbIe
"|  
input.close(); y,K> Wb9e  
} gYloY=.Z$'  
catch(IOException e){e.printStackTrace ();} >3}N
;  
catch(Exception e){e.printStackTrace ();} /]of@  
} ^a$L
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$-.*8*9  
private void processErrorCode(int nErrorCode) a`zHx3Yg  
{ %r&36d'  
System.err.println("Error Code : " + nErrorCode); Tfx-h)oP3  
} >*\yEH9"  
C}ASVywc,1  
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//停止文件下载 CF v]wS  
public void siteStop() 30<_`  
{ >DN^',FEm  
bStop = true; 3S1{r )[j  
for(int i=0;i<nStartPos.length;i++) t#%J=zF{  
fileSplitterFetch.splitterStop(); `~\8fN  
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5
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} d$8K,-M  
} u>:j$@56  
//负责部分文件的抓取 +O)ZB$w4  
**FileSplitterFetch.java a5&[O  
*/ A-*MH#QUKh  
package NetFox; )-h{0o  
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import java.io.*; wr~Qy4 ny  
import java.net.*; [Fv_~F491  
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public class FileSplitterFetch extends Thread { q\<NW%KtX  
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String sURL; //File URL c7R&/JV  
long nStartPos; //File Snippet Start Position c=^69>w  
long nEndPos; //File Snippet End Position BU7QK_zT:  
int nThreadID; //Thread's ID h)aLq  
boolean bDownOver = false; //Downing is over k=G c#SD5_  
boolean bStop = false; //Stop identical nU0##  
FileAccessI fileAccessI = null; //File Access interface @H^\PH?pp  
x=X&b%09  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N`qGwNT%G  
{ 16Jjf|]j  
this.sURL = sURL;
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this.nStartPos = nStart; N34bB>_  
this.nEndPos = nEnd; d[*NDMO  
nThreadID = id; :&LV^A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "ZA`Lp;%w  
} _ q AT%.  
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public void run() T5}5uk9  
{
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while(nStartPos < nEndPos && !bStop) Z_7TD)  
{ Fq`@sM$  
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try{ 2vddx<&  
URL url = new URL(sURL); \jS^+Xf?^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wRq f'  
httpConnection.setRequestProperty("User-Agent","NetFox"); uC6e2py<[  
String sProperty = "bytes="+nStartPos+"-"; V8b^{}nxt  
httpConnection.setRequestProperty("RANGE",sProperty); - s2Yhf  
Utility.log(sProperty); Hq>rK`  
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InputStream input = httpConnection.getInputStream(); Q
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//logResponseHead(httpConnection); xsrdHP
1  
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byte[] b = new byte[1024]; 3wfJ!z-E8  
int nRead; P(3$XMx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) RLGIST`  
{ nE:Wl  
nStartPos += fileAccessI.write(b,0,nRead); =,&{ &m)  
//if(nThreadID == 1) G {a;s-OA3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'lgS)m  
} RhE|0N=  
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Utility.log("Thread " + nThreadID + " is over!"); t1G2A`  
bDownOver = true; H{_6e6`e.  
//nPos = fileAccessI.write (b,0,nRead); ENf(E
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} qVds 2  
catch(Exception e){e.printStackTrace ();} 6*I=% H|  
} 1z@ ncqe  
} Cio(Ptt:  
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//打印回应的头信息 b'RBel;W  
public void logResponseHead(HttpURLConnection con) ,ZnL38GW  
{ Su'l &]  
for(int i=1;;i++) 0 Gq<APtr  
{ _G%kEt_4  
String header=con.getHeaderFieldKey(i); msw=x
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if(header!=null) VxU{ZD~<Z"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); WTZuf9:  
Utility.log(header+" : "+con.getHeaderField(header)); %y)LBSxf  
else BIT<J5>  
break; }w)wW1&  
} cn'rBY  
} Qaiqx"x3  
BqOMg$<\[  
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public void splitterStop() mEV@~){  
{ /qd~|[Kx:  
bStop = true; }/7rA)_  
} )N&95\u  
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85+w\KuEY  
} Oq95zo  
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?  
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/* H7Pw>Ta ;  
**FileAccess.java ;GZ'Rb  
*//文件访问(定位，写) &GI'-i  
package NetFox; i6E~]&~.v  
import java.io.*; 8ZDWaq8^2N  
E
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public class FileAccessI implements Serializable{ {JW_ZJx  
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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 ='HLA-uT  
RandomAccessFile oSavedFile; L>,xG.oG  
long nPos; A*
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public FileAccessI() throws IOException 8*(|uX  
{ ?O/!pUAu  
this("",0); Q_|Lv&  
} IHe?/oUL"b  
?;p45y~n%  
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public FileAccessI(String sName,long nPos) throws IOException tnw6[U!rh=  
{ c)17[9"  
oSavedFile = new RandomAccessFile(sName,"rw"); ]U5/!e  
this.nPos = nPos; P? LpI`f  
oSavedFile.seek(nPos); c nV2}U/\  
} _MUSXB'  
$`Aps7A  
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public synchronized int write(byte[] b,int nStart,int nLen) 2sT\+C&H  
{ S{qsq\X  
int n = -1; qjLFgsd  
try{ ?) VBkA5j  
oSavedFile.write(b,nStart,nLen); (Bu-o((N@0  
n = nLen; &+8cI^kp  
} :-1 i1d  
catch(IOException e) h,P#
)^"  
{ 'E#Bz"
T  
e.printStackTrace (); oF(|NS^  
} ~*ll,<L:  
&, WQ
r  
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return n; Lz}mz-N  
} RL1cx|  
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} O `a4 ")R  
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/* <5l!xzvw  
**SiteInfoBean.java kV+O|9  
*/ w:o,mzuXK  
package NetFox; hIMD2  
Y` tB5P  
I?%iJ%  
public class SiteInfoBean { ~!TRR.  
aak[U;rx  
`'M}.q,k~  
private String sSiteURL; //Site's URL by0M(h  
private String sFilePath; //Saved File's Path ma(E}s  
private String sFileName; //Saved File's Name ^jZ4tH3K  
private int nSplitter; //Count of Splited Downloading File 8K0@*0  
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FTC,{$  
public SiteInfoBean() V<G=pPC'H  
{//nSplitter的缺省值为5 B]|"ePj-  
//default value of nSplitter is 5 }o MY  
this("","","",5); ![4<6/2gy  
} T_*R^Ukb5  
b)Dzau  
@XFy^?  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !L_\6;aP,x  
{ tgB\;nbB  
sSiteURL= sURL; {%Q&CQG_  
sFilePath = sPath; $d_%7xx  
sFileName = sName; !/Wp0E'A  
this.nSplitter = nSpiltter; S,~DA3  
beCTOmC  
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} Km9Y_`?  
QvN=<V  
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public String getSSiteURL() *Af:^>mh  
{ ^%pM$3ov  
return sSiteURL; J}UG{RttI  
} c3$h-M(jVJ  
G 0;5I_D/  
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public void setSSiteURL(String value) HKZD*E((  
{ "=97:H{!  
sSiteURL = value; kLw
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} W{!GL  
N1O.U"L;  
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public String getSFilePath() #A '|O\RGP  
{ Q(\U'|%J  
return sFilePath; ^ A`@g4!
 
} E1uyMh-dy  
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5_MqpCL  
public void setSFilePath(String value) oSOO5dk:
z  
{ ]%y3*N@AZ  
sFilePath = value; |_^A$Hv  
} 2HemPth  
=
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public String getSFileName() }I1SC7gY  
{ `N69xAiy  
return sFileName; [?vn>  
}
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g{}{gBplnl  
public void setSFileName(String value) m6 )sX&  
{ t'@qb~sf  
sFileName = value; cCoa3U/  
} Xo{|m[,  
2$MIA?
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0=2D90  
public int getNSplitter() _'yN4>=6u  
{ 
.UUY9@  
return nSplitter; LXIQpD,M  
} LyRU2A  
I}#_Jt3R  
s:6pPJL  
public void setNSplitter(int nCount) [=63xPxs.  
{ 8%dE$smH  
nSplitter = nCount; q^e
4  
} 'n9<z)/,!  
} 2&f]v`|M|  
|,&5.|E 7  
uK:?6>H  
/* Yy$GfjJtL]  
**Utility.java 5w\>Whbd  
*/ 39|4)1e  
package NetFox; #sn2Vmi  
7g}lg
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public class Utility { v[r5!,F  
F ;o ^.  
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public Utility() r+}5;fQJ  
{ 7gLN
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jIq@@8@o  
} ]}3AP!:  
lzQmD/i*  
//线程睡眠 wF +9Iu
 
public static void sleep(int nSecond) Oie0cz:>:  
{ 9t.u9C=!F  
try{ v&hQ;v  
Thread.sleep(nSecond); ~w&P]L\dB  
} ewNzRH,b  
catch(Exception e) 03F%!Rm/j  
{ %_rdO(   
e.printStackTrace (); vtvF)jlX  
} {bxTODt@  
} j4ARGkK5B  
IXm}WTgF!  
//日志 5J d7<AO_  
public static void log(String sMsg) *}pl  
{ ,t`u3yk
h  
System.err.println(sMsg); (]JZ1s|  
} qq%\  
z=}@aX[  
cs]N%M^s  
public static void log(int sMsg) SLzxFuV  
{ ,]1oG=`3v  
System.err.println(sMsg); :ET05MFs\#  
} K%Dksx7ow  
} B0_[bQoc1  
RTPxAp+\5  
3#{{+5G  
/* ,/d R  
**TestMethod.java Mw=sW5Z  
*/ V-#OiMWa~  
package NetFox; T=/GFg'  
{[r}&^K15  
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public class TestMethod { *h+@a  
vx:MLmZ.  
N!7r~B   
public TestMethod() r:[N#*kK  
{ ///xx/weblogic60b2_win.exe + 9vd(
c  
try{ .~)[>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); u/`jb2eEU:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); wYZ"fusT  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~i`@  
fileFetch.start(); ls5s
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} s0,\[rM  
catch(Exception e){e.printStackTrace ();} S >E|A%  
tTWeOAF  
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} 
2h<{~;  
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@]*b$6tt  
public static void main(String[] args) %+PWcCmn  
{ 5F@7A2ZR  
new TestMethod(); Sq9I]A  
} qT`sPEs;V  
} czMu<@c [  
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