http断点续传简单实现（java)

/* k<^M >` $  
**SiteFileFetch.java sEdz`
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*/ e:9EP,  
package NetFox; V1V0T ,  
import java.io.*; {a:05Y  
import java.net.*; TI< x;p  
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public class SiteFileFetch extends Thread { d"#Zp&#  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !sm/BsmL7T  
long[] nStartPos; //开始位置 !V37ePFje  
long[] nEndPos; //结束位置 Ytlzn%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3$k#bC  
long nFileLength; //文件长度 e;6KxvX~  
boolean bFirst = true; //是否第一次取文件 SE]5cJ'>  
boolean bStop = false; //停止标志 4F~^RR"  
File tmpFile; //文件下载的临时信息 3Hom0g,V4  
DataOutputStream output; //输出到文件的输出流 w#9KtW,tt  
=L" 0]4K  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PFh ^Z L  
public SiteFileFetch(SiteInfoBean bean) throws IOException /^BC Qaj  
{ f`uRC-B/  
siteInfoBean = bean; 2(xC|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E s5:S#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'Be'!9K*d  
if(tmpFile.exists ()) `)n4I:)2  
{ Pj-INc96  
bFirst = false; \@:,A]  
read_nPos(); YS9RfK/  
} NFs5XpZ~  
else N"ga-u  
{ ;Y`Y1  
nStartPos = new long[bean.getNSplitter()]; .Q*X5Fc  
nEndPos = new long[bean.getNSplitter()]; [s{
!  
} St-uE|8  
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{ :tO RF  
} J/?Nf2L4  
// o.+?S  
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public void run() d]l8ei@>h  
{ e{P v:jl  
//获得文件长度 WKEb '^  
//分割文件 LmF,en5  
//实例FileSplitterFetch \beO5]KS<  
//启动FileSplitterFetch线程 C8}:z\A_@Z  
//等待子线程返回 }9'`3vsJ  
try{ :jLL IqhB  
if(bFirst) q!5:M\  
{ %SM;B-/zHt  
nFileLength = getFileSize(); +J X;T(T  
if(nFileLength == -1) g\JJkXjD#  
{ V0\[|E;F  
System.err.println("File Length is not known!"); HgF;[rq3Q  
} )\fY1WD  
else if(nFileLength == -2) f&^(f1WO  
{ pIJXP$v3  
System.err.println("File is not access!"); 4]y)YNQ(  
} pE
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else '-;[8:y.  
{ e<L@QNX  
for(int i=0;i<nStartPos.length;i++) 7^q~a(j  
{ m|@H`=`d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9Eyx Ob  
} ~?Q sr  
for(int i=0;i<nEndPos.length-1;i++) N4!`iS Y  
{ Dm>"c;2  
nEndPos = nStartPos[i+1]; IU
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} fd\RS1[  
nEndPos[nEndPos.length-1] = nFileLength; ):D"LC  
} ,^#Jw`w^  
} y/lF1{}5  
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//启动子线程 {*ak>Wud  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $cCC 1=dW  
for(int i=0;i<nStartPos.length;i++) V#t_gS  
{ X W)TI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Kx__&a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ji"g)d6  
nStartPos,nEndPos,i); 7RAB"T;?Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ISbs l=F  
fileSplitterFetch.start(); &],uD3:5O  
} =!O->C:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #o.e (C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >ZgzE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", z$32rt8{`v  
nEndPos = " + nFileLength); k_al*iM>H  
// fileSplitterFetch[nPos.length-1].start(); >qjV{M  
}]?Si6_ZZ  
1 DWoL}Z  
//等待子线程结束 157_0  
//int count = 0; \N>-+r  
//是否结束while循环 wl Oeoi  
boolean breakWhile = false; tli.g  
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while(!bStop) p\6cpf  
{ aV3:{oL  
write_nPos(); vJkc/7  
Utility.sleep(500); N%y i4  
breakWhile = true; ]b/]^1-(b  
)*,/L <  
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for(int i=0;i<nStartPos.length;i++) gV_/
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{
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if(!fileSplitterFetch.bDownOver) a^|DD#5  
{ dhl[=Y` Q  
breakWhile = false; BT$p~XB  
break; n/H OP  
} 0J)s2&H  
} KhCP9(A=Qo  
if(breakWhile) v<qh;2  
break; '=\}dav!  
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Y Y:BwW:  
//count++; f& 4_:'-,  
//if(count>4) CT|+?  
// siteStop(); Kz4S6N c  
} )s2] -n}W  
0&.CAHb}  
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System.err.println("文件下载结束！"); XZ rI w  
} v0^9"V:y  
catch(Exception e){e.printStackTrace ();} LSo!_tY  
} 8!g `bC#%  
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//获得文件长度 YeX*IZX8  
public long getFileSize() i%glQT  
{ +8=$-E=  
int nFileLength = -1; =lXj%V^8N  
try{ ?0tg}0|  
URL url = new URL(siteInfoBean.getSSiteURL()); da{]B5p\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $EMOz=)I#  
httpConnection.setRequestProperty("User-Agent","NetFox"); s:`i~hjq  
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int responseCode=httpConnection.getResponseCode(); G4&s_M$
 
if(responseCode>=400) DA
=U=F  
{ W+nu=iQ!  
processErrorCode(responseCode); r );R/)&  
return -2; //-2 represent access is error /YKd [RQ  
} d1/emwH  
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String sHeader; #c!:&9oU  
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for(int i=1;;i++) OI R5QH  
{ ]n ?x tI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  w-jElV  
//Utility.log(in.readLine()); 0MQ= Rt  
sHeader=httpConnection.getHeaderFieldKey(i); #F*|@  
if(sHeader!=null) o3ZN0j69|  
{ l/$GF|`U  
if(sHeader.equals("Content-Length")) JFq wC=-  
{ Zw]`z*,yRA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yu?5t?vf  
break; XGlt^<`  
} Fc[KIG3@  
} $o"
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else k<1yv$/mW  
break; l}{{7~C`  
} BT_]=\zi  
} ]]xKc5CT  
catch(IOException e){e.printStackTrace ();} Ku;fZN[g  
catch(Exception e){e.printStackTrace ();} ^-;S&=  
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Utility.log(nFileLength); U%{GLO   
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return nFileLength; ,RP-)j"Wff  
} gfk)`>E  
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//保存下载信息（文件指针位置） !+
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private void write_nPos() ?}||?2=P  
{ SNEhP5!  
try{ c0Ug
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output = new DataOutputStream(new FileOutputStream(tmpFile)); gW,
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output.writeInt(nStartPos.length);  a+h$u  
for(int i=0;i<nStartPos.length;i++) <+8'H:wz  
{ 0V%c%]PH  
// output.writeLong(nPos); 6K2e]r  
output.writeLong(fileSplitterFetch.nStartPos);  *7Dba5B  
output.writeLong(fileSplitterFetch.nEndPos); B6XO&I1c  
} tMr7d  
output.close(); &|SWy 2N  
} ]A4=/6`g?b  
catch(IOException e){e.printStackTrace ();} {+N< 9(O  
catch(Exception e){e.printStackTrace ();} Z:b?^u4.  
} EZtU6kW"  
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//读取保存的下载信息（文件指针位置） ~C-Sr@ a?/  
private void read_nPos() IQQv+af5  
{ [|\6AIoS  
try{ GR,2^]<{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $+gQnI3w  
int nCount = input.readInt(); Ht`fC|E  
nStartPos = new long[nCount]; 01bCP  
nEndPos = new long[nCount]; $Dg-;I  
for(int i=0;i<nStartPos.length;i++) l![M
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{ ~NGM6+9  
nStartPos = input.readLong(); rOIb9:  
nEndPos = input.readLong(); i4C{3J^  
} ?2<QoS  
input.close(); ",r v%i2 f  
} G

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catch(IOException e){e.printStackTrace ();} #h!+
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catch(Exception e){e.printStackTrace ();} c '|*{%<e2  
} |jsI-?%8J  
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private void processErrorCode(int nErrorCode) !E
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{ B`pBIUu  
System.err.println("Error Code : " + nErrorCode); cJKnB!iL5  
} N,t9X7G&  
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//停止文件下载 ,f03TBD}  
public void siteStop() OM'iJB6=  
{ 8jK=A2pTa  
bStop = true; gl
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for(int i=0;i<nStartPos.length;i++) eSPS3|YYn  
fileSplitterFetch.splitterStop(); $KcAB0 B8  
+]
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} wl=tN{R  
} NP>v@jO  
//负责部分文件的抓取 SH*'<  
**FileSplitterFetch.java ^Z (cVg  
*/ /E>;O47a  
package NetFox; f5}afPk  
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import java.io.*; yoE-
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import java.net.*; goM;Pf "<  
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public class FileSplitterFetch extends Thread { WC_.j^sW  
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String sURL; //File URL gI:g/ R  
long nStartPos; //File Snippet Start Position :kZ]Swi 5  
long nEndPos; //File Snippet End Position *h^->+0n  
int nThreadID; //Thread's ID lM-\:Q!
  
boolean bDownOver = false; //Downing is over \e a*  
boolean bStop = false; //Stop identical Qu
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FileAccessI fileAccessI = null; //File Access interface 0%xktf  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g4W
$MI  
{

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this.sURL = sURL; _z_YJ7A>  
this.nStartPos = nStart; `&;#A*C
0  
this.nEndPos = nEnd; ^![
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nThreadID = id; !D22HSv(w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 a[ULSYEi  
} lp*5;Ls'q  
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public void run() [bL
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{ vbJ<|#|r-  
while(nStartPos < nEndPos && !bStop) 6/!:vsa"3  
{ 288mP]a(v_  
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try{ ,7nu;fOT[  
URL url = new URL(sURL); (nqhX<T>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jMT[+f  
httpConnection.setRequestProperty("User-Agent","NetFox"); r$<!?Z  
String sProperty = "bytes="+nStartPos+"-"; &H_/`Z]Q  
httpConnection.setRequestProperty("RANGE",sProperty); GtRpgM  
Utility.log(sProperty); +:A `e+\  
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InputStream input = httpConnection.getInputStream(); 6 `6I<OJ\  
//logResponseHead(httpConnection); pbz
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{\Pk;M{Y&  
/.:1
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byte[] b = new byte[1024]; [_N1 .}e  
int nRead; LM<*VhX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) V7$ m.P#uM  
{ Yjg$o:M  
nStartPos += fileAccessI.write(b,0,nRead); 3P_.SF  
//if(nThreadID == 1) 1@Ba7>%'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Hc/7x).  
} e`Yj}i*bx]  
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Utility.log("Thread " + nThreadID + " is over!"); $GoS?\G  
bDownOver = true; j,rc9  
//nPos = fileAccessI.write (b,0,nRead); 8;M,l2pmR{  
} \t{iyUx
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catch(Exception e){e.printStackTrace ();} MpKXC  
} cg )(L;  
} #m#IBRD:  
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G-CL \G\n  
//打印回应的头信息 D(z
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public void logResponseHead(HttpURLConnection con) U& GPe
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{ mmQC9nZ  
for(int i=1;;i++) 4n#u?)  
{ H Qj,0#J)  
String header=con.getHeaderFieldKey(i); y^r'4zN'  
if(header!=null) X&Oo[Z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); u`EK^\R  
Utility.log(header+" : "+con.getHeaderField(header)); azZ|T{S  
else MdX4Rp'  
break; yCz"~c  
} Rd(8j+Q?ps  
} [KUkv  
,)
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public void splitterStop() P]"@3Z&w  
{ ?;=7{Ej  
bStop = true; 7L+Wj }m  
} 9#H0|zL  
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} &[`24Db  
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/* mAH7;u<  
**FileAccess.java 9f['T
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*//文件访问(定位，写) v~RxtTu  
package NetFox; u
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import java.io.*; :qS~"@?<  
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public class FileAccessI implements Serializable{ 6rS ? FG=  
i<&z'A6&]*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <F`9;WX  
RandomAccessFile oSavedFile; 2SU'lh\E  
long nPos; lC*xyOK  
tL&_@PD)3  
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public FileAccessI() throws IOException DKo6lP`  
{ qV=O;  
this("",0); )~P<ruk>,C  
} ,!SbH  
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public FileAccessI(String sName,long nPos) throws IOException bO6z;
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{ "-fyX!  
oSavedFile = new RandomAccessFile(sName,"rw"); &=zJ MGa  
this.nPos = nPos; 0"-H34M<D  
oSavedFile.seek(nPos); 1`II%mf[  
} i Q3wi  
K[SzE{5=P  
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public synchronized int write(byte[] b,int nStart,int nLen) HJr*\%D}1  
{ WKr4S<B8mr  
int n = -1; L9[m/(:y  
try{ ^`-Hg=d  
oSavedFile.write(b,nStart,nLen); %jUZc:06  
n = nLen; 0o6r3xc;  
} 5Bcmz'?!  
catch(IOException e) X:FyNUa  
{ ;J?fK69%  
e.printStackTrace (); ^=I[uX-3ue  
} xR'd}>`  
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return n; aSm</@tO&  
} *~`oA~-Q  
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} j%vxCs>  
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/* 84(jg P  
**SiteInfoBean.java 1_~'?'&^  
*/ 7Aw <:  
package NetFox; T~>&m~} +  
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v@X[0J_8  
public class SiteInfoBean { Mc  
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private String sSiteURL; //Site's URL qyIy xJ  
private String sFilePath; //Saved File's Path 6{Bvl[mhI  
private String sFileName; //Saved File's Name M~sP|Ha"+  
private int nSplitter; //Count of Splited Downloading File gi A(VUwI>  
ieyqp~+|4$  
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public SiteInfoBean() KE)^S [Da  
{//nSplitter的缺省值为5 j

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//default value of nSplitter is 5 XF4NRs  
this("","","",5); RvW>kATb_F  
} I7ySm12}  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7 dG_E]&  
{ F,5}3$  
sSiteURL= sURL; yErvgf  
sFilePath = sPath; 'bef3P9`  
sFileName = sName; .|ZnU]~T  
this.nSplitter = nSpiltter; 6Hpj&Qm  
4.&et()}  
7_7^&.Hh  
} {*|$@%y!  
Z=?qf$.}  
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public String getSSiteURL() vCR\lR+  
{ TwE&5F*  
return sSiteURL; Lj3q?>D*^6  
} [h :FJ  
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public void setSSiteURL(String value) $r)nvf`\  
{ Y0OVzp9 b  
sSiteURL = value; {QLqf  
} )3_g&&  
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public String getSFilePath() `=foB-(zt  
{ |B*`%7{+  
return sFilePath; CV,[x[L#{  
} qoD M!~  
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public void setSFilePath(String value) fm% Y*<Y"  
{ zPoIs@  
sFilePath = value; z3}4+~~  
} xZ"kJ'C4}  
t#g6rh&  
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public String getSFileName() z[, `  
{ ;c>Rjg&[  
return sFileName; 'uOp?g'7  
} Ie;}k;?-  
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:!EOg4%i  
public void setSFileName(String value) WxLILh  
{ M*c`@\  
sFileName = value; sXSZ#@u,WN  
} pKSVT  
Ec]cCLB  
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public int getNSplitter() g'b)]Q  
{ v4<x 4  
return nSplitter; /SD2e@x{U  
} :XZ  
.~ W^P>t  
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public void setNSplitter(int nCount) iyhB;s5Rgw  
{ 5k}UXRB?  
nSplitter = nCount; o' DXd[y  
} W,
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} ',* 6vbII  
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/* p.1|bXY`  
**Utility.java M+^+u 1QQ0  
*/ 7QRtNYo#\  
package NetFox; {B
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public class Utility { ji2if.t@  
(#.)~poZ  
/$x6//0If  
public Utility() T[eTT]Z{Ia  
{ TM':G9
n  
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} *$_<| g)9  
;comL29l2`  
//线程睡眠 W~QZ(:IK  
public static void sleep(int nSecond) +kl@`&ga  
{ TO)wjF_  
try{ M|`%4vk>  
Thread.sleep(nSecond); BiHBu8
<  
} _"F(w"|  
catch(Exception e) rC<m6  
{ QTK{JZf  
e.printStackTrace (); =N n0)l  
} _Oq (&I  
} g!%csf  
c66Iy"  
//日志 :/Nz' n  
public static void log(String sMsg) `h Y:F(  
{ U]ouBG8/  
System.err.println(sMsg); +Mv0X%(N  
} `^afbW  
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9!FV.yp%F  
public static void log(int sMsg) zYj8\iER  
{ Q_1EAxt  
System.err.println(sMsg); Vo(d)"m?  
} +]|J  
} 8F4#
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/* +2W#=G  
**TestMethod.java %-T]!3"n  
*/ Ar=pzQ<Z{  
package NetFox; T cSj`-  
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public class TestMethod { 3QS"n.d  
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"v~w#\pz7  
public TestMethod() E<&VK*{zcO  
{ ///xx/weblogic60b2_win.exe Ctt{j'-[  
try{ 1p9f& w  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); '(u
[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~&4,w9b)j  
SiteFileFetch fileFetch = new SiteFileFetch(bean); it>FG9hVo  
fileFetch.start(); O*yc8fUI  
} CWI(Q`((>  
catch(Exception e){e.printStackTrace ();} T?7ZF+yo6  
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7,jh44(\=  
} UmQ 9_H7  
n&
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public static void main(String[] args) m2<sVTN`^  
{ 0
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new TestMethod(); jB?Tua$,s  
} 2J|Yc^b6  
} uu=e~K  
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