http断点续传简单实现（java)

/* `jr?I {m;  
**SiteFileFetch.java RjgJIVm(  
*/ +?
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package NetFox; H[OgnnM  
import java.io.*; IoK/2Gp  
import java.net.*; }a
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public class SiteFileFetch extends Thread { %yjD<2J;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean q{B?j%.o  
long[] nStartPos; //开始位置 n|rKo<Y0  
long[] nEndPos; //结束位置 q~W:W}z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bX:h"6{=R  
long nFileLength; //文件长度 ;b1B*B  
boolean bFirst = true; //是否第一次取文件 i`+bSg  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 5F ^VvzNn  
DataOutputStream output; //输出到文件的输出流 lQ!OD&6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） S
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public SiteFileFetch(SiteInfoBean bean) throws IOException Yc_(g0NK  
{ ?YS 3)  
siteInfoBean = bean; SA=>9L,2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); M3|G^q:l  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dkCUU  
if(tmpFile.exists ()) '6>*J  
{ <LXx_{=:  
bFirst = false; xh9$ZavB*  
read_nPos(); v3XM-+Z4  
} z,^~H  
else p nI=
 
{ )78T+7Kq  
nStartPos = new long[bean.getNSplitter()]; ^-
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nEndPos = new long[bean.getNSplitter()]; nu-&vX  
} :E~rve'  
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} t:vBVDkD  
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public void run() !d!u{1Y&  
{ XM` H@s7  
//获得文件长度 yzzJKucVU:  
//分割文件 qnj'*]ysBC  
//实例FileSplitterFetch |rZM
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//启动FileSplitterFetch线程 =EA:fq  
//等待子线程返回 oo7}Hg>  
try{ Yb/*2iWX  
if(bFirst) 9`
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{ 9:VUtx#}2  
nFileLength = getFileSize(); 8 p[n>qV9  
if(nFileLength == -1) |}UkVLc_^  
{ \( #"g  
System.err.println("File Length is not known!"); >-<iY4|[d  
} V(DY!f_%  
else if(nFileLength == -2) j4!O,.!T  
{ {)!>e  
System.err.println("File is not access!"); 1
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} ,#&7+e!]>P  
else 5Lej_uqF   
{ 51#OlvD  
for(int i=0;i<nStartPos.length;i++)  +)e|>  
{ (?JdiY/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); bDtb6hL  
} fC*cqc~{@  
for(int i=0;i<nEndPos.length-1;i++) -,p=;t#(  
{ @v#P u_  
nEndPos = nStartPos[i+1]; \i%mokfbc  
} :Ez,GAk  
nEndPos[nEndPos.length-1] = nFileLength; $#u'XyA  
} N
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} ?&~q^t?u  
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//启动子线程 ]6)u$4X6$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; x4H#8ZK!  
for(int i=0;i<nStartPos.length;i++) [p`5$\e  
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tS]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), y5m2u8+  
nStartPos,nEndPos,i); l&qCgw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _"yA1D0d_  
fileSplitterFetch.start(); e}d(.H%l0  
} uij^tN%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RLnL9)`W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !+^'Ej)z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y`bTf@EP>  
nEndPos = " + nFileLength); sAL ]N][Y  
// fileSplitterFetch[nPos.length-1].start(); 31G0B_T  
Y6sX|~Zy  
p T8?z  
//等待子线程结束 x}?<9(nE c  
//int count = 0; Wx{E\ l  
//是否结束while循环 ~:bdS 4w  
boolean breakWhile = false; 'Uf?-t*LT@  
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while(!bStop) sEdz`
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{ vb6EO[e%I  
write_nPos(); F1L[3D^-  
Utility.sleep(500); !!^z6jpvn  
breakWhile = true; <dH@e  
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for(int i=0;i<nStartPos.length;i++) d)YlD]I  
{ 3 J04 $cD  
if(!fileSplitterFetch.bDownOver) }:ZA)  
{ 7D#y  
breakWhile = false; iT4*~(p 3  
break; vCaN[  
} UGhEaKH~R  
} [c 8=b,EI  
if(breakWhile) H,X|-B  
break; +ZOiL[rS  
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//count++; qMNWw\k  
//if(count>4) P)=.Du)  
// siteStop(); #l
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} ZLv/otf:|"  
vv @m{,7#Y  
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System.err.println("文件下载结束！"); 2Kz+COP+  
} xZ9:9/Vg  
catch(Exception e){e.printStackTrace ();} n_e'n|T  
} ?W'p&(;  
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//获得文件长度 ,94<j,"  
public long getFileSize() zzQWHg]/  
{ Lqj Q
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int nFileLength = -1; U4pIRa)S  
try{ !SQcV'  
URL url = new URL(siteInfoBean.getSSiteURL()); 9RaO[j`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (G>[A}-  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;[sW\Ou  
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d qn5G!fI  
int responseCode=httpConnection.getResponseCode(); a[O6xA%  
if(responseCode>=400) LSJ?;Zg(=z  
{ .gRj^pu   
processErrorCode(responseCode); $RPW/Lyiq  
return -2; //-2 represent access is error }~XWtWbd-  
} 'jtC#:ePK  
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String sHeader; f&^(f1WO  
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for(int i=1;;i++) pE
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{ '-;[8:y.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e<L@QNX  
//Utility.log(in.readLine()); 7^q~a(j  
sHeader=httpConnection.getHeaderFieldKey(i); m|@H`=`d  
if(sHeader!=null) 9Eyx Ob  
{ L[G O6l  
if(sHeader.equals("Content-Length")) ??rS h Mu  
{ o%$.8)B9F  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9)q3cjP{<  
break; 5AYOM=O]t  
} %a;#]d  
} RdTM5ANT  
else i--t ?@#  
break; ut{T:kT  
} j9+$hu#a  
} >gk_klLh  
catch(IOException e){e.printStackTrace ();} Lx^ eaP5  
catch(Exception e){e.printStackTrace ();} /U~|B
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Utility.log(nFileLength); ji"g)d6  
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return nFileLength; P#,u9EIJ  
} G6sK3K  
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//保存下载信息（文件指针位置） ggr  
private void write_nPos() ;;Q^/rkC  
{ )O]T}eI  
try{ WSkGVQu  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =l,P'E  
output.writeInt(nStartPos.length); 0B NLTRv  
for(int i=0;i<nStartPos.length;i++) xt{'Be&Ya+  
{ +L(amq;S  
// output.writeLong(nPos); _'u]{X\k{J  
output.writeLong(fileSplitterFetch.nStartPos); E
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output.writeLong(fileSplitterFetch.nEndPos); )D)5 `n)  
} ^QB[;g.O  
output.close();
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} p*Bty@CRi  
catch(IOException e){e.printStackTrace ();} J3K=z  
catch(Exception e){e.printStackTrace ();} 7|P kc(O  
} U@lc1#  
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//读取保存的下载信息（文件指针位置） ^URCnJ67Se  
private void read_nPos() mP(3[a_Q  
{ @fL ^I&++  
try{ Nk`UQ~g$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Hd|l6/[xz  
int nCount = input.readInt(); n/H OP  
nStartPos = new long[nCount]; 0J)s2&H  
nEndPos = new long[nCount]; KhCP9(A=Qo  
for(int i=0;i<nStartPos.length;i++) {|+Y;V`  
{ (L_-!=e  
nStartPos = input.readLong(); !d*[QD8  
nEndPos = input.readLong(); IP~!E_e}\  
} ^4y]7p  
input.close(); =8kmFXo  
} US6_5>/  
catch(IOException e){e.printStackTrace ();} 092t6D}  
catch(Exception e){e.printStackTrace ();} ;t`  ?|  
} EP;/[O  
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private void processErrorCode(int nErrorCode) (JhX:1  
{ N0U/u'J!g  
System.err.println("Error Code : " + nErrorCode); X'9.fKp  
} X|M!Nt0'  
=BsV`p7rU  
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//停止文件下载 DT1gy:?L  
public void siteStop() [&Xp]:M'D  
{ (}"D x3K
 
bStop = true; TQ Vk;&A  
for(int i=0;i<nStartPos.length;i++) 2EY"[xK|  
fileSplitterFetch.splitterStop(); ?HZp@&  
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} J3Mb]X)_}  
} q>q:ZV  
//负责部分文件的抓取 0bNvmZ$  
**FileSplitterFetch.java bm588UQ  
*/ +Qs]8*^?;  
package NetFox; k_=SDm a  
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import java.io.*; OI R5QH  
import java.net.*; ]n ?x tI  
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public class FileSplitterFetch extends Thread { 3JoY
-  
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String sURL; //File URL .{Y;6]9[  
long nStartPos; //File Snippet Start Position kH!Z|Ps?R  
long nEndPos; //File Snippet End Position ><%585  
int nThreadID; //Thread's ID [;E%o^/^  
boolean bDownOver = false; //Downing is over @0`A!5h?u  
boolean bStop = false; //Stop identical TFVQfj$r  
FileAccessI fileAccessI = null; //File Access interface ,N/@=As9$  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vNv?trw  
{ fF:57*ys  
this.sURL = sURL;
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this.nStartPos = nStart; 8$Q`wRt(%  
this.nEndPos = nEnd; l=^A41L_  
nThreadID = id; vccWe7rh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 r^9l/H~$  
} 4.6$m  
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public void run() 1CtUf7 `/Q  
{ gfk)`>E  
while(nStartPos < nEndPos && !bStop) wAMg"ImJ  
{ \lL[08G  
!+
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try{ Jx*cq;`Vee  
URL url = new URL(sURL); J5@08bZm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 77
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httpConnection.setRequestProperty("User-Agent","NetFox"); ^df wWP  
String sProperty = "bytes="+nStartPos+"-"; Z['.RF'`  
httpConnection.setRequestProperty("RANGE",sProperty); +^I0>\  
Utility.log(sProperty); GqFx^d
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;yH>A ;,K%  
5
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InputStream input = httpConnection.getInputStream(); 
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//logResponseHead(httpConnection); =j]y?;7q  
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byte[] b = new byte[1024]; nx9PNl@?V  
int nRead; zVhyAf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _ %s#Cb  
{ jiI=tg;  
nStartPos += fileAccessI.write(b,0,nRead); # @\3{;{R  
//if(nThreadID == 1) wcHk]mLM  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %cNN<x8  
} ;5a$OM  
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Utility.log("Thread " + nThreadID + " is over!"); Pz]WT1J0  
bDownOver = true; +a#&W}K  
//nPos = fileAccessI.write (b,0,nRead);
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} ,CE/o7.FG  
catch(Exception e){e.printStackTrace ();} >Wg=
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} Y#U.9>h  
} 9t! d.
}  
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//打印回应的头信息 G

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public void logResponseHead(HttpURLConnection con) #h!+
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{ c '|*{%<e2  
for(int i=1;;i++) |jsI-?%8J  
{ ktu?-?#0,  
String header=con.getHeaderFieldKey(i); kuY^o,u-1e  
if(header!=null) Y
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); X<ex >sM  
Utility.log(header+" : "+con.getHeaderField(header)); ;W|kc</R*  
else UhB+c  
break; ?7\V)$00(&  
} ^0,}y]5p  
} /%$Zm^8c  
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+cpb!YEAb
 
public void splitterStop() 1nVQYqT_  
{ 2g(_Kdj*{  
bStop = true; qLR;:$]Q&8  
} t]c<HDCK  
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} a=S &r1s>  
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:@
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/* vE]ge  
**FileAccess.java ~Nh6po{  
*//文件访问(定位，写) F`}'^>  
package NetFox; )! [B(  
import java.io.*; #83  
]+lT*6P*  
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public class FileAccessI implements Serializable{ WC_.j^sW  
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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 2"0VXtv6  
RandomAccessFile oSavedFile; gI:g/ R  
long nPos; !G%!zNA S  
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public FileAccessI() throws IOException 2[ sY?C  
{ tqZ91QpW  
this("",0); s
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} 88Pt"[{1  
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public FileAccessI(String sName,long nPos) throws IOException g4W
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{ vc#o(?g  
oSavedFile = new RandomAccessFile(sName,"rw"); b[vE!lJEq  
this.nPos = nPos; Rtf<UhUn  
oSavedFile.seek(nPos); u5CSx'h]  
} !D22HSv(w  
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public synchronized int write(byte[] b,int nStart,int nLen) TtJX(N~  
{ He_O+[sc  
int n = -1; ?Ld),A/c  
try{ ~B<\#oO  
oSavedFile.write(b,nStart,nLen); eDd&vf  
n = nLen; #y\O+\4e  
} &Vj@){  
catch(IOException e) $.,PteYK  
{ j;$f[@0o  
e.printStackTrace (); >iyNZ]."\  
} ``xm##K  
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return n; W83d$
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} 3qV^RW&  
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} tbQY&TO1  
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/* F'~r?D  
**SiteInfoBean.java .]9`eGVWj  
*/ j)ic7b  
package NetFox; besc7!S  
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public class SiteInfoBean { 2e6P?pX~2  
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private String sSiteURL; //Site's URL 1^IMoC7$#  
private String sFilePath; //Saved File's Path AyJl
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private String sFileName; //Saved File's Name 5a |R  
private int nSplitter; //Count of Splited Downloading File 1dD%a91  
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cg )(L;  
public SiteInfoBean() #m#IBRD:  
{//nSplitter的缺省值为5 x.t<@y~  
//default value of nSplitter is 5 ;apLMMsWC  
this("","","",5); g.\b@0Uy'  
} AB $N`+&
 
(~@.9&cBD  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *gmc6xY  
{ TJ)Nr*U3_  
sSiteURL= sURL; ->#wDL!6  
sFilePath = sPath; o.$48h(  
sFileName = sName; :F d1k Jm  
this.nSplitter = nSpiltter; Rd(8j+Q?ps  
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} <\*)YKjn/@  
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public String getSSiteURL() d{TcjZ  
{ +@$VJM%^7b  
return sSiteURL; hl[<o<`Q  
} l>jrY1u  
%n]jsdE^|  
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public void setSSiteURL(String value) `+=Zq :0  
{ C,,T7(: k  
sSiteURL = value; 6l|L/Z_6  
} ?23J(;)s  
)^UqB0C6^  
dLQp"vs$  
public String getSFilePath() +:m)BLA4l  
{ lf\"6VIsR  
return sFilePath; /XG7M=A$o  
} i~GW  
&tkPZ*}#1  
s"7FmJ\7rw  
public void setSFilePath(String value) *K>2B99TXu  
{ 2U%t  
sFilePath = value; D~qi6@
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} nUY)LnI  
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public String getSFileName() q2k}bb +  
{ -X*.scw  
return sFileName; !'\(OFv9Im  
} gy1kb,MO  
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public void setSFileName(String value) Y&VypZ"G>  
{ ~+6#4<M.~  
sFileName = value; C&q}&=3r  
} 4o''C |ND  
G>Bgw>#_  
//G&=i$  
public int getNSplitter() FpttH?^  
{ 6 y"r'  
return nSplitter; h*4wi.-  
} "% i1zQo&  
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public void setNSplitter(int nCount) ,:.8s>+i  
{ <-d-. 8  
nSplitter = nCount; NgGpLdaC2v  
} r
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} vr>J$(F  
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/* a"+/fC`  
**Utility.java CE183l\  
*/ yl<=_Q  
package NetFox; 9<Zm}PE32  
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public class Utility { Q1h v2*/U  
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public Utility() 8=\k<X{`  
{ {YzpYc1  
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} TDtHRhq7  
EY1L5Ba.  
//线程睡眠 LGy!{c  
public static void sleep(int nSecond) Yv*i69"  
{ xoSBMf  
try{ oxCfSA  
Thread.sleep(nSecond); IxP$lx  
} 'u[cT$  
catch(Exception e) =F*{O=  
{ '?|.#D#-c  
e.printStackTrace (); OUHd@up@n  
} +w?1<Z  
} v|kL7t)}  
Q
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//日志 |?fc]dl1]  
public static void log(String sMsg) ,"5p=JX`  
{ is-{U?-  
System.err.println(sMsg); RML'C:1  
} Zfr?(y+3  
* 8D(Lp1  
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public static void log(int sMsg) (7aE!r\Ab  
{ Bq:: 5,v  
System.err.println(sMsg); 7"_gX  
} I'cM\^/h  
} ,wra f#UdP  
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64!V8&Ay  
/* 6~+?DIc  
**TestMethod.java *Oe;JqQkK  
*/ Lop=._W  
package NetFox; VM ny>g&3  
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public class TestMethod { > cJX'U9  
=>h~<88#5  
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public TestMethod() !FnH;  
{ ///xx/weblogic60b2_win.exe 2TC7${^9}J  
try{ =HvLuVc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F9SIC7}uH  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j#XU\G  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (aH_K07  
fileFetch.start(); 7<ES&ls_  
} q}R"  
catch(Exception e){e.printStackTrace ();} |7T!rnr  
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;c>Rjg&[  
} 'uOp?g'7  
Ie;}k;?-  
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public static void main(String[] args) My'6yQL  
{ 4a~9?}V:  
new TestMethod(); 4B8{\"6  
} pRdO4?l  
} &"svt2  
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