http断点续传简单实现（java)

/* "Ij
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**SiteFileFetch.java I0Ia6w9  
*/ ?ny=  
package NetFox; uh3)0.nR  
import java.io.*; xBM>u,0.F  
import java.net.*; `'4)q}bB  
= [@)R!3H  
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public class SiteFileFetch extends Thread { ?vtX"Fdz  
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SiteInfoBean siteInfoBean = null; //文件信息Bean v;2CU  
long[] nStartPos; //开始位置 4{na+M  
long[] nEndPos; //结束位置 S\x=&Rz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p9[6^rjx8  
long nFileLength; //文件长度 >s EjR!  
boolean bFirst = true; //是否第一次取文件 ql{_%x?  
boolean bStop = false; //停止标志 L8$1K&!  
File tmpFile; //文件下载的临时信息 Ib`-pRU;  
DataOutputStream output; //输出到文件的输出流 yi6N-7  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） pmc=NTr&<  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3=.Y,ENM;  
{ On_@HQ/FI  
siteInfoBean = bean; })F*:9i*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1=VJ&D;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6^F'|Wh  
if(tmpFile.exists ()) P,xwSvO#M  
{ '+y_\  
bFirst = false; 9^ed-h Bf  
read_nPos(); KG9t3<-`  
} gwB\<rzG  
else Qyh/ed/  
{ yW7'?  
nStartPos = new long[bean.getNSplitter()]; |zsbW9 W*m  
nEndPos = new long[bean.getNSplitter()]; 7=}F{U  
} ocRdbmS  
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} GF<[}  
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public void run() oOU
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{ Pcd *">v  
//获得文件长度 WrGK
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//分割文件 TpfZ>d2  
//实例FileSplitterFetch Ty4S~ClO#'  
//启动FileSplitterFetch线程 5]Da{Wmgs  
//等待子线程返回 .IrNa>J
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try{ :z"!kzdJ  
if(bFirst) #?O&  
{ #
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nFileLength = getFileSize(); *|:Q%xr-  
if(nFileLength == -1) #KpY6M-H  
{ eny/ fm  
System.err.println("File Length is not known!"); m
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} B;#J"6w  
else if(nFileLength == -2) k[|~NLB8  
{ ixfdO\nU  
System.err.println("File is not access!"); 1}m3;  
} IVvtX}  
else l&(l$@t  
{ 3c'#6virz  
for(int i=0;i<nStartPos.length;i++)
;/O#4]2*  
{ lx0~>K]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); rxZi8w>}  
} qv2!grp]*W  
for(int i=0;i<nEndPos.length-1;i++) R[[ ,q:4  
{ m]Y;c_DO:  
nEndPos = nStartPos[i+1]; K`%tGVY  
} 0HeD{TH\  
nEndPos[nEndPos.length-1] = nFileLength; \.{AAj^qD  
} X"asfA[6K  
} },-*  
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//启动子线程 ,ZE?{G{tuj  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :*i f  
for(int i=0;i<nStartPos.length;i++) {=:#S+^ER  
{ f
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,I.WX,OR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?,knit2x  
nStartPos,nEndPos,i); -%c<IX>z9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6cS>bl  
fileSplitterFetch.start(); X*eW#|$\  
} w|Cx>8P8@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uBnoQ~Qd[z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K!z
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p]G3)s@>  
nEndPos = " + nFileLength); w!^~<{Kz  
// fileSplitterFetch[nPos.length-1].start(); k;yw#Af8  
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//等待子线程结束 `8_z!)  
//int count = 0; CON0E~"  
//是否结束while循环 )Di \_/G  
boolean breakWhile = false; \Q$
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while(!bStop) k\r(=cex6  
{ <
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write_nPos(); ;T+pu>)  
Utility.sleep(500); QfjN"25_  
breakWhile = true; H U+ I  
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for(int i=0;i<nStartPos.length;i++) "UVFU-Z  
{ zDOKShG  
if(!fileSplitterFetch.bDownOver) h11.'Eej`  
{ %b2oiKSBx?  
breakWhile = false; e( X|3h|  
break; LaMLv<)k  
}  UL@9W6  
} !c#]?b%  
if(breakWhile) V7Yaks  
break; X|LxV]  
;QCrHqRT`  
H6TD@kL9Wr  
//count++; *>8ce-PV  
//if(count>4) ZAKeEm2A  
// siteStop(); d4?d4;{  
} Mz]:}qmFA  
5sO@OV\ y  
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System.err.println("文件下载结束！"); Y4.Eq+$gh  
} [V8fu qE>  
catch(Exception e){e.printStackTrace ();} M\<w#wZ  
} E ]9\R  
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//获得文件长度 'T=~jA7SkT  
public long getFileSize() ./6<r OW  
{ 0C%W&;r0  
int nFileLength = -1; eJCjJ)  
try{ 6vKS".4C  
URL url = new URL(siteInfoBean.getSSiteURL()); una%[jTc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nKr9#JebRC  
httpConnection.setRequestProperty("User-Agent","NetFox"); K4Dp:2/K%  
|]=2 }%1w  
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int responseCode=httpConnection.getResponseCode(); ^eYqll/U  
if(responseCode>=400) SO\/-]9#  
{ 7%?jL9Vw  
processErrorCode(responseCode); _,74)l1  
return -2; //-2 represent access is error yF._*9Q3hK  
} G_H?f\/  
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T GB_~Bqe  
String sHeader; BG&c
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for(int i=1;;i++) SlLw{Yb7\.  
{ R8ONcG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); t`'iU$:1f  
//Utility.log(in.readLine()); 4\ c,)U}  
sHeader=httpConnection.getHeaderFieldKey(i); q"qo.TPh|$  
if(sHeader!=null) zLw{ {|  
{ lq:}0<k  
if(sHeader.equals("Content-Length")) zhI#f0c  
{ 6M.;@t,Y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /c2'dJ(H  
break; =SOe}!  
} ?|{XZQ~  
} 3oZ=k]\  
else '|>9C^E9X  
break; uQb!=]  
} bAk&~4Y_"  
} T^<>Xiam  
catch(IOException e){e.printStackTrace ();} r\6"5cQ=  
catch(Exception e){e.printStackTrace ();} 3Ug  
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Utility.log(nFileLength); AdZ;j6#  
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return nFileLength; nP~({:l8X  
}  6Si-u  
5v\!]?(O;  
w9RS)l2FQ  
//保存下载信息（文件指针位置） M@1r:4CoKH  
private void write_nPos() vR6Bn  
{ x3ERCqTR  
try{ 5l-mW0,MK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3ss6_xd+  
output.writeInt(nStartPos.length); ^\:8w0Y^  
for(int i=0;i<nStartPos.length;i++) q-ES6R  
{ `~UZU@/x  
// output.writeLong(nPos); |tzg:T;  
output.writeLong(fileSplitterFetch.nStartPos); bOp54WI-g  
output.writeLong(fileSplitterFetch.nEndPos); 1{Mcs%W;w5  
} FSuAjBl0-  
output.close(); iJxQB\x  
} h0Z{,s}  
catch(IOException e){e.printStackTrace ();} g$:Xuw1  
catch(Exception e){e.printStackTrace ();} Si9Z>MR  
} Q^K"8 ;  
8.=\GV  
\,Lo>G`!  
//读取保存的下载信息（文件指针位置） ;8S/
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private void read_nPos() >N\0"F7.  
{ 
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try{ l%z<(L5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *Oc.9 F88"  
int nCount = input.readInt(); Awv`)"RAR  
nStartPos = new long[nCount]; %owsBO+  
nEndPos = new long[nCount]; yV3^Qtb!  
for(int i=0;i<nStartPos.length;i++) ZD#9&q'4<  
{ vKwQXR~C  
nStartPos = input.readLong(); Z}A%=Z\/3  
nEndPos = input.readLong(); >>Ts??  
} Cp`j/rF  
input.close(); p,pR!qC>  
} @4(k(  
catch(IOException e){e.printStackTrace ();} SQ,?N XZ  
catch(Exception e){e.printStackTrace ();} <!$:8ls  
} S_T^G` [  
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private void processErrorCode(int nErrorCode) WnwhSr2  
{ \k`n[{  
System.err.println("Error Code : " + nErrorCode); (C] SH\  
} LWsP ya  
']-@?sD$  
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//停止文件下载 '$As<LOEd/  
public void siteStop() Q(d9n8  
{ oBq 49u1  
bStop = true; q{2I_[p  
for(int i=0;i<nStartPos.length;i++) o~FRF0f*VP  
fileSplitterFetch.splitterStop(); 49Df?sx  
*tOG*hwdT  
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} UmnE@H"t$\  
} e6X[vc|Y}  
//负责部分文件的抓取 6J~12TU,  
**FileSplitterFetch.java o[ENp'r  
*/ O<)y-nx;X  
package NetFox; LIU}a5  
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import java.io.*; &AuF]VT  
import java.net.*; S|rgCh!h  
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public class FileSplitterFetch extends Thread { cr?7O;,  
=z?%;4'|  
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String sURL; //File URL 8;y&Pb~)  
long nStartPos; //File Snippet Start Position rV({4cIe9R  
long nEndPos; //File Snippet End Position vB37M@wm  
int nThreadID; //Thread's ID G1t\Q-|l0  
boolean bDownOver = false; //Downing is over mDGn:oRj  
boolean bStop = false; //Stop identical @cRZk`|1n  
FileAccessI fileAccessI = null; //File Access interface P X;Ed*y  
/:<IIqO
.  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Uw-p758dD  
{ \ 6EKgC1  
this.sURL = sURL; LAx4Xp/  
this.nStartPos = nStart; @`-[;?>  
this.nEndPos = nEnd; 6OiSK@<Hk  
nThreadID = id; GEjd7s]C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 VKm!Ri$  
} /!}'t  
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public void run() O=)  
{ H$ftGwS8  
while(nStartPos < nEndPos && !bStop) ~`>e5OgOJ  
{ /2{
5;  
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try{ z3t~}aL  
URL url = new URL(sURL); o ]Jv;Iy@?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s{ V*1$e~  
httpConnection.setRequestProperty("User-Agent","NetFox"); r4x3$M c  
String sProperty = "bytes="+nStartPos+"-"; \^1+U JU  
httpConnection.setRequestProperty("RANGE",sProperty); &`Y!;@K9W#  
Utility.log(sProperty); =5D nR  
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InputStream input = httpConnection.getInputStream(); E^_wI>  
//logResponseHead(httpConnection); iFSJL,QZ3  
q;5i4|  
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byte[] b = new byte[1024]; DlMe5=n-u  
int nRead; dk QaM@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @4%L36k  
{ UL
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nStartPos += fileAccessI.write(b,0,nRead); J
68j=`Y  
//if(nThreadID == 1) I"AYWo
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ub0/r$]DK  
} $(s\{(Wn  
_$<Gyz*  
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Utility.log("Thread " + nThreadID + " is over!"); 5`~mmAUk;`  
bDownOver = true; 3QI?[R.  
//nPos = fileAccessI.write (b,0,nRead); %xwIt~Y  
} )Fd HV;K  
catch(Exception e){e.printStackTrace ();} rQ4*k'lA:  
} 4fh^[\  
} 0s#vwK13  
}MR1^  
7;.xc{  
//打印回应的头信息 -Z4{;I[Q@  
public void logResponseHead(HttpURLConnection con) +u@aJ_^
 
{ X.O
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for(int i=1;;i++) 2c<&eX8"  
{ $=sXAK9   
String header=con.getHeaderFieldKey(i); IUGz =%[  
if(header!=null) A>VI{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?6Cz[5\  
Utility.log(header+" : "+con.getHeaderField(header)); rdJm{<  
else |5I'CNi\  
break; xy+QbDT  
} "O+5R(XT  
} nmlPX7!{$  
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_2fkb=2@  
public void splitterStop() 0,*%vG?Q  
{ qP!eJ6[Nh"  
bStop = true; P ]N [y  
} Jxf~&!zR  
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;vhyhP.oM  
} A6<C-1 N}j  
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/* u{&B^s)k.  
**FileAccess.java =9L$L|W  
*//文件访问(定位，写) {-9jm%N  
package NetFox; ^\ ?O4,L  
import java.io.*; +&tgJ07A  
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(-
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public class FileAccessI implements Serializable{ +i `*lBup$  
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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 '"pd  
RandomAccessFile oSavedFile; 3[p_!eoW  
long nPos; ?wMHS4  
K*K1(_x=  
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public FileAccessI() throws IOException F}Mhs17!|  
{ G DSfT{kK\  
this("",0); ,F+B Wot4  
} N;F)jO xsl  
iMF<5fLH&  
'f8(#n=6qP  
public FileAccessI(String sName,long nPos) throws IOException -0o[f53}p  
{ I9$c F)zk  
oSavedFile = new RandomAccessFile(sName,"rw"); XXmE+aI  
this.nPos = nPos; )j6eE+gF  
oSavedFile.seek(nPos); oC*ees g_  
} L^kp8
o^$  
+5<k-0v  
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public synchronized int write(byte[] b,int nStart,int nLen) WV;=@v  
{ P#kGX(G9!  
int n = -1; D|I Ec?  
try{ :(3|HTz  
oSavedFile.write(b,nStart,nLen); NX* O_/  
n = nLen; ir>]r<Zl  
} 5FvOznK^e  
catch(IOException e) <dA8 '7^  
{ u%
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e.printStackTrace (); |YJCWFbs8  
} Qx|H1_6  
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q)u2Y]  
return n; tury<*  
} 3K/Df#  
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} p?(L'q"WK  
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/* Ftb%{[0}u3  
**SiteInfoBean.java O/AE}]  
*/ Df07y<>7Q  
package NetFox; 4FeEGySow  
KHiFJ_3  
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public class SiteInfoBean { `T*U]/zQ  
YZ#V#[j'^  
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private String sSiteURL; //Site's URL _68BP)nz>.  
private String sFilePath; //Saved File's Path noVa=aU^  
private String sFileName; //Saved File's Name U S
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private int nSplitter; //Count of Splited Downloading File yFIy`9R  
6y+b5-{'  
wjU.W5IR  
public SiteInfoBean()  ~m=EM;  
{//nSplitter的缺省值为5 I\P Bu$Ww  
//default value of nSplitter is 5 2F_ R/{D  
this("","","",5); ?v]
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} rp! LP#*  
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;#?M)o:q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ucYkxi`x  
{ IxSV?k   
sSiteURL= sURL; >X}{BDMb.  
sFilePath = sPath; V%L/8Q~  
sFileName = sName; g1m
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this.nSplitter = nSpiltter; @_'OyRd8  
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} *3{J#Q6fk3  
~GB=Nz  
^i%A7pg  
public String getSSiteURL() ~2}Pl)  
{ @Z(rgF{{  
return sSiteURL; ~&G4)AM  
} $`Nd?\$  
'8`T|2  
tn<6:@T  
public void setSSiteURL(String value) M8W#io  
{ j\
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sSiteURL = value; W*T{,M@Y  
} 3><u*0qe%I  
9w~cvlv[  
I=dGq;Jaz  
public String getSFilePath() ?qHF}k|  
{ e$l6gY  
return sFilePath; LVtu*k   
} 9Ld9N;rWm#  
<bmLy_":  
hq_~^/
v\  
public void setSFilePath(String value) y%(X+E"n*  
{ Ub)I66  
sFilePath = value; z_SagU,\  
} <&#+E%E4  
-e`;bX_N)  
] pPz@@xx  
public String getSFileName() 0Oxz3r%}r  
{ hb^!LtF#Y  
return sFileName; D!FaEN  
} ," R>}kPli  
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public void setSFileName(String value) 1p\Ak  
{ qc8Ta"  
sFileName = value; 7[o {9Yp&  
} "n?<2 wso  
(O5)wej   
`.BR=['O  
public int getNSplitter() UmP'L!  
{ T!^Mvat  
return nSplitter; }=GM?,7b  
} &TT":FPR  
"~$$  
1kFjas`g  
public void setNSplitter(int nCount) [8]m8=n  
{ X , ZeD  
nSplitter = nCount; xPQL?.  
} jXIE
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} p5*lEz|$  
J/Q|uRpmqr  
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/* l
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**Utility.java |-kEGLH[*V  
*/ jxY-u+B  
package NetFox; $Ub}p[L  
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4;<DJ.XlN=  
public class Utility { h5onRa*
7  
0=[0|`x  
Y6eEGo"K.+  
public Utility() S<oQ}+4[~  
{ iHz[Zw^.s  
@>O&Cpt  
v]bAWo  
} f=ib9WbR#  
-
9G]x{>  
//线程睡眠 &5q{viI  
public static void sleep(int nSecond) p.Y$A if.  
{ 7%CIt?Z%  
try{ `
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Thread.sleep(nSecond); gMZ&,n4  
} u%opY<h  
catch(Exception e) L>nO:`>h  
{ #v8Cy|I  
e.printStackTrace (); 79tJV  
} BX$hAQ(6Q  
} `Cj,HI_/*  
ryEvmWYu  
//日志 "6V_/u5M;=  
public static void log(String sMsg) hEOJb @:R  
{ $FCw$+w  
System.err.println(sMsg); ^Kw(&v  
} L?f qcW{  
1URsHV!xcM  
bOXh|u_3i  
public static void log(int sMsg) 6Bdyf(t  
{ b\L)m (  
System.err.println(sMsg); %HE
mi;  
} cdsQ3o  
} 9p<:LZd~  
+{ab1))/  
#$uZDQY_  
/* n4*'B*  
**TestMethod.java -A@U0=o  
*/ [+DNM 2A  
package NetFox; rk|a'&  
C
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'#f?#(  
public class TestMethod { ~~dfpW_"  
JS2!)aqc  
{G.{ad  
public TestMethod() 6QptKXu7  
{ ///xx/weblogic60b2_win.exe yHw!#gWM  
try{ bV7QVu8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s=jO;K$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `w=!o.1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); riEqW}{  
fileFetch.start(); )`RZkCe  
} fiqj;GW  
catch(Exception e){e.printStackTrace ();} ^z?=?%{  
]}_,U!`8  
"0Y&~q[=  
} L4mTs-M.  
hGKdGu`0  
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public static void main(String[] args) #ZwY?T x  
{ (QhAGk&lu  
new TestMethod(); |Kn^w4mN  
} cFxSDTR  
} RA~_
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