http断点续传简单实现（java)

/* E
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**SiteFileFetch.java 9 ?(P?H  
*/ aj6{  
package NetFox; V1>>]]PS  
import java.io.*; nk+*M9r|I  
import java.net.*; I.L8A|nZ  
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public class SiteFileFetch extends Thread { >a5avSn  
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SiteInfoBean siteInfoBean = null; //文件信息Bean K}YOs.  
long[] nStartPos; //开始位置 '<KzWxuC  
long[] nEndPos; //结束位置 #Cz6
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 Q=cbHDB  
long nFileLength; //文件长度 aFrVP  
boolean bFirst = true; //是否第一次取文件 !Knv/:+  
boolean bStop = false; //停止标志 PdD|3B&  
File tmpFile; //文件下载的临时信息 lITZ|u  
DataOutputStream output; //输出到文件的输出流 K#],4OG  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） x1ID6kI[{*  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?FRQ!R  
{ vy+9Q5@W  
siteInfoBean = bean; w=H4#a?fc  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v^_<K4N`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5`3f"(ay/  
if(tmpFile.exists ()) Fttny]  
{ f{[,
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bFirst = false; ~IE5j,SC  
read_nPos(); i|Y_X  
} pY9>z;qD  
else ,As78^E{  
{ ,`JXBI~  
nStartPos = new long[bean.getNSplitter()]; 4';]fmf@[i  
nEndPos = new long[bean.getNSplitter()]; CQcb !T  
} !jDqRXi(  
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}  s!E-+Gw  
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public void run() E4'D4@\W  
{ r}~l(  
//获得文件长度 ]&ptld;  
//分割文件 }m<)$.x|P  
//实例FileSplitterFetch 'ga1SbA]  
//启动FileSplitterFetch线程 2r~ Nh](  
//等待子线程返回 FZ^byIS[  
try{ vN7ihe[C  
if(bFirst) ~5wCehSb  
{ -7">A~c  
nFileLength = getFileSize(); [21tT/  
if(nFileLength == -1) }# -N7=h  
{ f41!+W=  
System.err.println("File Length is not known!"); AN
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} t MB;GIb#  
else if(nFileLength == -2) _pNUI{De  
{ yg2~qa:dZ  
System.err.println("File is not access!"); I01On>"@7  
} .@APxeU  
else 2+GF:[$  
{ xsFWF*HPs  
for(int i=0;i<nStartPos.length;i++) EW4XFP4 c  
{ kozg8 `\]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nwN<Q\]S  
} ORx,n7
-  
for(int i=0;i<nEndPos.length-1;i++) (7ew&u\Li  
{ r+0)l:{.  
nEndPos = nStartPos[i+1]; `s:| 4;.  
} =WEfo;  
nEndPos[nEndPos.length-1] = nFileLength; ^s5.jlZr@  
} z7PPwTBa  
} O~,^x$ve  
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5[gkGKkf_  
//启动子线程 ;5Sr<W\:;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; J*U(f{Q(  
for(int i=0;i<nStartPos.length;i++) jSYj+k  
{ ;*Z w}51  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >;
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Wt3\&.n  
nStartPos,nEndPos,i); //+
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $e*Nr=/  
fileSplitterFetch.start(); e#'`
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} s*l_O*$'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7GP?;P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); p[o2F5 T2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `z=MI66Nl  
nEndPos = " + nFileLength); _ _)Z Q  
// fileSplitterFetch[nPos.length-1].start(); r\3In-(AT  
|\_O8=B%  
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//等待子线程结束 C3_*o>8  
//int count = 0; +bO{UC[  
//是否结束while循环 T]vD ,I+  
boolean breakWhile = false; *Cb(4h-  
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while(!bStop) ^2??]R&Q  
{ 8@qahEgQ  
write_nPos(); gvU6p[D  
Utility.sleep(500); isd[l-wAmf  
breakWhile = true; Z0'3.D,l  
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for(int i=0;i<nStartPos.length;i++) u3ZG;ykM  
{ ;dWqMnV  
if(!fileSplitterFetch.bDownOver) ~xJD3Qf  
{ @KpzxcEoO  
breakWhile = false; r"Bf@va  
break; DuE>KX{<!R  
} 1=D!C lcb  
} zm}
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if(breakWhile) fBF}-{VX(  
break; ='JX_U`A^F  
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}"8_$VDcz  
//count++; _YJwF1e+M  
//if(count>4) 2<O8=I _  
// siteStop(); "L)pH@)  
} 4J_%quxO  
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System.err.println("文件下载结束！"); 4mAtYm  
} v\ox:C  
catch(Exception e){e.printStackTrace ();} 96.Wfx  
} 9j"\Lr*o"  
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//获得文件长度 (NQ[AypMI  
public long getFileSize() ,*4"d._Y  
{ 'SieZI
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int nFileLength = -1; e>^R 8qM?  
try{ hJ<2bgQo  
URL url = new URL(siteInfoBean.getSSiteURL()); %FU[j^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B<R-|-#  
httpConnection.setRequestProperty("User-Agent","NetFox"); T82_`u  
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-
0
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int responseCode=httpConnection.getResponseCode(); x\DkS,O  
if(responseCode>=400) m&q;.|W  
{ r
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processErrorCode(responseCode); twtDyo(\  
return -2; //-2 represent access is error K)?^
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} 0- UeFy  
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b {5|2&=  
String sHeader; D'h2 DP!  
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for(int i=1;;i++) CA4-&O"  
{ 0Nu]N)H5<l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K*9b `%  
//Utility.log(in.readLine()); rieQ&Jt"  
sHeader=httpConnection.getHeaderFieldKey(i); @nP}q!y  
if(sHeader!=null) mSfhl(<L  
{ VO Qt{v{1|  
if(sHeader.equals("Content-Length")) /aqN`  
{ wM)w[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u-_$?'l;~  
break; ?C:fP`j:  
} _kHpM:;.  
} =]a@
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else p|d9g ^  
break; 0EOX@;}  
} _6!/}Fm  
} [bG>qe1}&  
catch(IOException e){e.printStackTrace ();} j>xVy]v=|  
catch(Exception e){e.printStackTrace ();} I_G>W3  
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Utility.log(nFileLength); EcoUpiL%2  
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return nFileLength; Iv72;ZCh?6  
} ~8t}*oV   
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//保存下载信息（文件指针位置） Qz+d[%Q}x  
private void write_nPos() `^L<db^A  
{ $|(|Qzi%  
try{ N&APq
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output = new DataOutputStream(new FileOutputStream(tmpFile)); I~LQ1_  
output.writeInt(nStartPos.length); SU O;  
for(int i=0;i<nStartPos.length;i++) :ECK $Cu  
{ ~f10ZB_k>'  
// output.writeLong(nPos); 2ZbY|8X$r  
output.writeLong(fileSplitterFetch.nStartPos); I"sobZ`  
output.writeLong(fileSplitterFetch.nEndPos);
v^W?o}W  
} l5';?>!s  
output.close(); CY3\:D0I  
} @P"`=BU&  
catch(IOException e){e.printStackTrace ();} :F>L;mp  
catch(Exception e){e.printStackTrace ();} on;sq8;  
} l~4e2xoT  
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//读取保存的下载信息（文件指针位置） "1!.^<V*  
private void read_nPos() :+ 9Ft>  
{ J)8pqa   
try{ +%}5{lu_e  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wGzXp5 dl  
int nCount = input.readInt(); CES
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nStartPos = new long[nCount]; 7tl)4A6  
nEndPos = new long[nCount]; rfXF 01I  
for(int i=0;i<nStartPos.length;i++) \e:FmG  
{ Rhv".epz  
nStartPos = input.readLong(); ?X_0Iy}1  
nEndPos = input.readLong(); xeYySM=  
} Ec*--]j*c  
input.close(); e,#+Xx0M  
} ?%dCU~ z  
catch(IOException e){e.printStackTrace ();} ;h-G3>Il  
catch(Exception e){e.printStackTrace ();} eW"x%|/Q7  
} }`9fZK{. @  
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private void processErrorCode(int nErrorCode) ?mYV\kDt\  
{ C`)^~C_]`3  
System.err.println("Error Code : " + nErrorCode); mU?&\w=v$  
} ;ad9{":J#B  
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//停止文件下载 g`)/x\  
public void siteStop() PK-}Ldj  
{ r\l3_t  
bStop = true; UPVO~hB;  
for(int i=0;i<nStartPos.length;i++) ZM-/n>  
fileSplitterFetch.splitterStop(); =p,4=wo{  
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} }P&1s,S8J#  
} l${Hgn+  
//负责部分文件的抓取 1F3QI|  
**FileSplitterFetch.java  +eDN,iv  
*/ 2\nB
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package NetFox; vGPf`2/j.  
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import java.io.*; I5TQ>WJbf  
import java.net.*; SgCqxFii  
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public class FileSplitterFetch extends Thread { 0,1L e$)6  
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String sURL; //File URL pjX%LsX\  
long nStartPos; //File Snippet Start Position S|{Yvyp  
long nEndPos; //File Snippet End Position dt-Qu},8-  
int nThreadID; //Thread's ID ]689Q%D  
boolean bDownOver = false; //Downing is over [0%yJH  
boolean bStop = false; //Stop identical z&C{8aQ'  
FileAccessI fileAccessI = null; //File Access interface :c~9>GCE&  
:Bx+WW&P.i  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f"ZqA'KB#  
{ ; d, JN  
this.sURL = sURL; ,-cpsN  
this.nStartPos = nStart; zK' _e&*  
this.nEndPos = nEnd; lgCHGv2@  
nThreadID = id; wE,=%?"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P|unUW(P  
} vKU]80T  
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public void run() %mK3N2N$  
{ SE-!|WR  
while(nStartPos < nEndPos && !bStop) W\I$`gyC/  
{ [<en1  
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try{ -vv
 
URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =gMaaGg p,  
httpConnection.setRequestProperty("User-Agent","NetFox"); jGk7=}nw  
String sProperty = "bytes="+nStartPos+"-"; VR
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httpConnection.setRequestProperty("RANGE",sProperty); S_(&UeTC  
Utility.log(sProperty); S`pF7[%rp  
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InputStream input = httpConnection.getInputStream(); 4/*]`  
//logResponseHead(httpConnection); q6;OS.f  
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byte[] b = new byte[1024]; L/qZ ;{  
int nRead; ^z[_U}N\}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [TRGIGtq  
{ [WcS[](ob  
nStartPos += fileAccessI.write(b,0,nRead); keT?,YI  
//if(nThreadID == 1) y,'FTP9?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k)$iK2I  
} %3]3r*e&5  
9|J8]m?x  
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Utility.log("Thread " + nThreadID + " is over!"); D"`%|`O  
bDownOver = true; Zr\2BOcc.l  
//nPos = fileAccessI.write (b,0,nRead); X tJswxw`K  
} Hm.X}HO0L  
catch(Exception e){e.printStackTrace ();} zSEr4^Dk4  
} bZxv/\
  
} /DLr(  
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@; W<dJ<X  
//打印回应的头信息 0w^jls  
public void logResponseHead(HttpURLConnection con) 929#Q#TT  
{ 0v;ve  
for(int i=1;;i++) d
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{  UP\8w#~  
String header=con.getHeaderFieldKey(i); j1'\R+4U  
if(header!=null) G"}qV%"6"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !.9l4@z#  
Utility.log(header+" : "+con.getHeaderField(header)); #o"tMh!f  
else EJO.'vQ  
break; wUbmzP.  
} <MRC%!.  
} j6`6+W=S(  
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public void splitterStop() N0]z/}hd@  
{ t9ER;
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bStop = true; "K8nxnq  
} &Y 'z?N  
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} C2NzP& FD  
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/* RTA%hCr!  
**FileAccess.java 6!@0VI&P  
*//文件访问(定位，写) P1$f}K}  
package NetFox; e "_&z# 2_  
import java.io.*; E`~i-kf  
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public class FileAccessI implements Serializable{ k@
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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 YRXK@'[=  
RandomAccessFile oSavedFile; cY{I:MA+h@  
long nPos; #0(fOHPQ  
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public FileAccessI() throws IOException $khrWiX  
{ O /vWd"  
this("",0); }N@n{bu+  
} 9g96 d-  
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public FileAccessI(String sName,long nPos) throws IOException f:S}h-AL&  
{ )x)gHY8;  
oSavedFile = new RandomAccessFile(sName,"rw"); s~=g*99H  
this.nPos = nPos; D
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oSavedFile.seek(nPos); 1}`2\3,  
} YKNb59k  
TKd6MZhT  
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public synchronized int write(byte[] b,int nStart,int nLen) XYMxG:  
{  C[R`Ml  
int n = -1; $:(z}sYQ7  
try{ 3Qa?\C&4  
oSavedFile.write(b,nStart,nLen); p x0Sy
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n = nLen; LGAX
"/LX  
} UPR/XQ  
catch(IOException e) Ep<YCSQy$i  
{ .5]{M\aA  
e.printStackTrace (); A
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} }{A?PHV5  
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return n; ]r!Qm
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} Et.j1M|g  
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} .8:+MW/  
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/* I=o'+>az  
**SiteInfoBean.java [t$4Tdd  
*/ :SK<2<8h  
package NetFox; ?3Pazc]+|  
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public class SiteInfoBean { y #69|G  
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private String sSiteURL; //Site's URL KI`11lJW~  
private String sFilePath; //Saved File's Path zWb-pF|  
private String sFileName; //Saved File's Name UP]1(S?  
private int nSplitter; //Count of Splited Downloading File nGns}\!7'  
`Klrr  
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public SiteInfoBean() `\ R{5TU  
{//nSplitter的缺省值为5 aLYLd/ KV  
//default value of nSplitter is 5 K0oFPDJN  
this("","","",5); dl_{iMhF&E  
} =q5@
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jWSb5#Pw  
{ -zTEL(r  
sSiteURL= sURL; ol<lCp  
sFilePath = sPath;
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sFileName = sName; xHe^"LL  
this.nSplitter = nSpiltter;
06jMj26!  
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>D~w}z/fk  
} aHC%19UN  
FQ!Oxlq,Q  
'bPk'pj9  
public String getSSiteURL() ;iQ
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{ +9C;<
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return sSiteURL; ED/FlL{  
} 8 URj1
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public void setSSiteURL(String value) {+Sq<J_`M  
{  NpR6  
sSiteURL = value; C\
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} "wINBya'M  
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public String getSFilePath() V^2-_V]8  
{ )!sa)\E?  
return sFilePath; ~#Aa Ldq  
} [ f34a  
LABNj{=D!  
"{ FoA3g|  
public void setSFilePath(String value) a_{6Qdl  
{ i-.c=M  
sFilePath = value; mW +tV1XjG  
} lhxdx   
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public String getSFileName() L/fRF"V  
{ SX_4=^  
return sFileName; 'F7VM?HBfg  
} 6v>z h  
)*D'csGc  
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public void setSFileName(String value) o%qkqK1  
{ c3W BALdh  
sFileName = value; <[<24
7%  
} PUCx]5  
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|7c`(.  
public int getNSplitter() )5GQJiY  
{ Q7(eq0na  
return nSplitter; Y&GuDLUF  
} W_}/O'l{  
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q~O>a0f0  
public void setNSplitter(int nCount) SH=:p^J  
{ p:tN642  
nSplitter = nCount; Noz&noq  
} enumK\  
} zo44^=~%  
7P*Z0%
Q  
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/* _z]v<,=3M  
**Utility.java #HG&[Ywi  
*/ choL%g}  
package NetFox; 1Z 6SI>p  
o(Kcs-W2  
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public class Utility { GX5W^//}  
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public Utility() jsZY{s=  
{ W_m!@T"@H  
-[$&s FD  
(:OHyeNt  
} O<`,,^4w/  
0!_*S )  
//线程睡眠 Q!]IG;3Sx|  
public static void sleep(int nSecond) D$hQyhz'  
{ :H\&2/j  
try{ Lzz)n%y5  
Thread.sleep(nSecond); g}r^Xzd;  
} x.\XUJ4x  
catch(Exception e) oLP]N$'#  
{ : I)Gv  
e.printStackTrace (); :x+ig5  
} :t5uDKZ_j)  
} n;qz^HXEJ  
Pw xIz  
//日志 |[ocyUsxX  
public static void log(String sMsg) ^6qjSfFW}  
{ }$:#+ (17  
System.err.println(sMsg); ^jOCenE3  
} <soj&f+  
{,Fcd(MU  
 0Ve%.k  
public static void log(int sMsg) ]>vf9]  
{ iokPmV  
System.err.println(sMsg); AsAFUuI  
} z{M8Yf |  
} bP03G=`6w  
(H1lqlVWV#  
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/* 8nsZ+,@+[  
**TestMethod.java *:j-zrwu&  
*/ uP Rl[tS0  
package NetFox; gY%&IHQ'  
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t9Vb~ Ubdb  
public class TestMethod { Xy!&^C` J`  
3G.r-  
*/Cj$KY70  
public TestMethod() )Oe`s(O@[I  
{ ///xx/weblogic60b2_win.exe )7w@E$l"  
try{ .HCaXFW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >[8#hSk  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %wtXo BJ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !%wdn33"  
fileFetch.start(); m r2S!  
} ZMe}M!V  
catch(Exception e){e.printStackTrace ();} pX^=be_  
b"&E,=L  
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} KqK9X  
on_H6Y@B52  
{( dP  
public static void main(String[] args) h(|;\~  
{ 7dHIW!OA  
new TestMethod(); vS#{-X  
} Fn> <q:  
} `1q|F9D  
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