http断点续传简单实现（java)

/* SFqq(K2u  
**SiteFileFetch.java 6N.MCB^  
*/ S&'-wAEd  
package NetFox; LO)QEU
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import java.io.*; zR}vR9Ls  
import java.net.*; tz%H1`  
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public class SiteFileFetch extends Thread { X@~R<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZVCa0Km  
long[] nStartPos; //开始位置 D#X&gE  
long[] nEndPos; //结束位置 /J&_ZDNV~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 LT/*y=  
long nFileLength; //文件长度 iDlg>UYd  
boolean bFirst = true; //是否第一次取文件 FOuPj+}F  
boolean bStop = false; //停止标志 1_)Y{3L  
File tmpFile; //文件下载的临时信息 |eej}G(,m}  
DataOutputStream output; //输出到文件的输出流 ^O3p:X4u  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
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public SiteFileFetch(SiteInfoBean bean) throws IOException *47%|bf`  
{ +3-f$/po  
siteInfoBean = bean; S$nEflcz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |<LW(,|A  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U{3Pk0rZ  
if(tmpFile.exists ()) ->@iw!5xu  
{ fvoPV&:  
bFirst = false; WAGU|t#."  
read_nPos(); snny! 0E\m  
} W0# VDe]>  
else @P<Mc)o^  
{ `=I@W  
nStartPos = new long[bean.getNSplitter()]; q&: t$tSS  
nEndPos = new long[bean.getNSplitter()]; !f#[4Xw  
} (KphAA8  
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} Jrx]/CM  
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public void run() bHmn0fZ9  
{ h.aXW]]}(P  
//获得文件长度 r59BBW)M  
//分割文件 g|x*sZR~Y  
//实例FileSplitterFetch #lx(F3  
//启动FileSplitterFetch线程 Pb/[945  
//等待子线程返回 1K{hj%  
try{ h%U,g 9_  
if(bFirst) bVds23q  
{ ]bAw>1,NVD  
nFileLength = getFileSize();
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if(nFileLength == -1) 8?$XT  
{ O
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System.err.println("File Length is not known!"); /m+.5Qz9)@  
} dqw0ns.2  
else if(nFileLength == -2) tQIz  
{ A
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System.err.println("File is not access!"); #(r1b'jfP  
} DMd&9EsRG  
else v cb}Gk  
{ (l:LG"sy\  
for(int i=0;i<nStartPos.length;i++) Ly`FU)  
{ {tF)%>\#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); RVa{%  
} sm;\;MP*yH  
for(int i=0;i<nEndPos.length-1;i++) *!yY7 ~#  
{ 1IZTo!xi  
nEndPos = nStartPos[i+1]; MK, $#  
} Ve\P,.  
nEndPos[nEndPos.length-1] = nFileLength; `:EU
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} 8
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} xU$15|ny  
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//启动子线程 o\:vxj+%*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; tcj3x<  
for(int i=0;i<nStartPos.length;i++) 420yaw/":  
{ ,M$J yda  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MHAWnH8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), NLO&.Q]#  
nStartPos,nEndPos,i); R ;3!?`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r*W&SU9Z  
fileSplitterFetch.start(); &W-1W99auE  
} S *K0OUq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qiyJ4^1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \Gz 79VW  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", LkUi^1((e  
nEndPos = " + nFileLength); yI_MYL[  
// fileSplitterFetch[nPos.length-1].start(); X
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<5sP%Fs)  
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//等待子线程结束 [fr!J?/@  
//int count = 0; ny[\yj4F  
//是否结束while循环 YEhPAQNj  
boolean breakWhile = false; eLN[`hJ  
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while(!bStop) dmUa\1g#  
{ _&/2-3]\B  
write_nPos(); 6eAJ>9@x  
Utility.sleep(500); =FXq=x%9+  
breakWhile = true; @!2vS@f  
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for(int i=0;i<nStartPos.length;i++) mA0|W#NB  
{ -3&mgd  
if(!fileSplitterFetch.bDownOver) +{"w5o<CO  
{ ]`_eaW?Ua  
breakWhile = false; RWINdJZ  
break; 0;x<0P  
} x @uowx_&m  
} +"Mlj$O  
if(breakWhile) 2U`g[1  
break; `NARJ9M   
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;>h:VnV(>(  
//count++; J2Z?}5>  
//if(count>4) 2M3C 5Fu  
// siteStop(); C?lZu\L  
} uy oEMT#u  
E
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System.err.println("文件下载结束！"); QVPJ$~x  
} '=]|"  
catch(Exception e){e.printStackTrace ();} O*+,KKPt  
} @RFJe$%  
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//获得文件长度 Ej/P:nB  
public long getFileSize() $' >|r]  
{
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int nFileLength = -1; WS1$cAD2N  
try{ x$/:%"E  
URL url = new URL(siteInfoBean.getSSiteURL()); k{w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C9"yu&l  
httpConnection.setRequestProperty("User-Agent","NetFox"); |A19IXZ\  
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int responseCode=httpConnection.getResponseCode(); xzOM\Nq?O  
if(responseCode>=400) `Fs-z  
{ ^DOQ+  
processErrorCode(responseCode); R:t  
return -2; //-2 represent access is error DzE_p- zs  
} ps@{1Rn1  
-%6Y&_5VK  
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String sHeader; anxwK47  
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for(int i=1;;i++) (ixlFGvEq  
{ TM^.y Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b<"LUM*;  
//Utility.log(in.readLine()); Jqgo\r%`  
sHeader=httpConnection.getHeaderFieldKey(i); 5R/k8UZ  
if(sHeader!=null) N"&qy3F  
{ pm k;5 d  
if(sHeader.equals("Content-Length")) 37nGFH`K2m  
{ \K(QE ~y'W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); OysO55
i  
break; |g8Q.*"l[  
} A<<Bm M.%  
} 1n|K   
else 8$y5) ~Q  
break; i $;y  
} 7=[/J*-m  
} R?H[{AX  
catch(IOException e){e.printStackTrace ();} =
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catch(Exception e){e.printStackTrace ();} NncII5z  
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Utility.log(nFileLength); g RBbL1  
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return nFileLength; mZ}C)&,m2  
} [V_\SQV0  
4'BZ+A,p  
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//保存下载信息（文件指针位置） R1NwtnS  
private void write_nPos() Q9NKQuSu  
{ -VhxnhS  
try{ @86?!0bt  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QPJz~;V2  
output.writeInt(nStartPos.length); g.d~`R@v  
for(int i=0;i<nStartPos.length;i++) qhqqCVrsW  
{ %hH@< <b(s  
// output.writeLong(nPos); $V2.@X  
output.writeLong(fileSplitterFetch.nStartPos); h;S?  
output.writeLong(fileSplitterFetch.nEndPos); Kuy0Ci  
} BhCOT+i;c  
output.close(); X82
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} ]d -U
  
catch(IOException e){e.printStackTrace ();} G "`t$=0  
catch(Exception e){e.printStackTrace ();} `as6IMqJD  
} Z}s56{!.  
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<n{-&;>  
//读取保存的下载信息（文件指针位置） KB6`OT^b{r  
private void read_nPos() ooIA#u  
{ ,ou&WI yC  
try{ !;h`J:dN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ry!0~ir  
int nCount = input.readInt(); ~#y(]Xec2  
nStartPos = new long[nCount];  V4qv7  
nEndPos = new long[nCount]; R"V^%z;8o  
for(int i=0;i<nStartPos.length;i++) '5 kSr(  
{ 't<hhjPqY  
nStartPos = input.readLong(); #AUV&pI[  
nEndPos = input.readLong(); p~NFiZ,  
} S^*ME*DDz  
input.close(); U t'r^  
} ]B>g~t5J  
catch(IOException e){e.printStackTrace ();} ERZWK  
catch(Exception e){e.printStackTrace ();} G*\U'w4w|*  
} /j:fc?yv  
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private void processErrorCode(int nErrorCode) 6h3TU,$r  
{ fs;pX/:FR  
System.err.println("Error Code : " + nErrorCode); u RPvo}!=1  
} %% A==_b  
a<d$P*I(cH  
u[~= a5:4  
//停止文件下载 jpRC
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public void siteStop() AxZaV;%*  
{ 3}ATt".  
bStop = true; 4VrL@c @  
for(int i=0;i<nStartPos.length;i++) CGY,I UG  
fileSplitterFetch.splitterStop(); Xw_6SR9C  
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+!Lz]@9K  
} iDrQ4>  
} unN=yeut  
//负责部分文件的抓取 Fvae
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**FileSplitterFetch.java x!QA* M  
*/ Xl\yOMfp  
package NetFox; 6 ~d\+aV  
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import java.io.*; $mLiEsJ  
import java.net.*; v7@O ,%  
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public class FileSplitterFetch extends Thread {
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}j6<S-s~  
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String sURL; //File URL d6ABgQi0  
long nStartPos; //File Snippet Start Position gPzp/I  
long nEndPos; //File Snippet End Position 2E_*'RT  
int nThreadID; //Thread's ID DX#_0-o  
boolean bDownOver = false; //Downing is over G;Thz  
boolean bStop = false; //Stop identical >C
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FileAccessI fileAccessI = null; //File Access interface /{HK0fd  
):pFI/iC  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1H]E:Bq  
{ B#Z-kFn@  
this.sURL = sURL; 'Bb@K[=s  
this.nStartPos = nStart; /woC{J)4p  
this.nEndPos = nEnd; <N}*|z7=b  
nThreadID = id; to"[r  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 a-Ef$(i_  
} z}f;_NX  
CY i{WV(:  
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public void run() c`x[C  
{ ga+Z6|t  
while(nStartPos < nEndPos && !bStop) w\2yippI  
{ \jGvom.  
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try{ 2i_X{!0}  
URL url = new URL(sURL); vhj^R5=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =as\Tp#d  
httpConnection.setRequestProperty("User-Agent","NetFox"); t?404  
String sProperty = "bytes="+nStartPos+"-"; Xsit4Ma  
httpConnection.setRequestProperty("RANGE",sProperty); 4[^lE?+  
Utility.log(sProperty); >W7IWhm3  
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InputStream input = httpConnection.getInputStream(); Zk#?.z}  
//logResponseHead(httpConnection); >HlQ+bl$xw  
;?'=*+'>  
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byte[] b = new byte[1024]; iz pFl@WS  
int nRead; j~:N8(=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ajMI7j^G  
{ PquATAzQA  
nStartPos += fileAccessI.write(b,0,nRead); @E5}v  
//if(nThreadID == 1) 1ps_zn(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h<ULp&g  
} Owz.C_{)  
b1NB:  
'I *&P5|  
Utility.log("Thread " + nThreadID + " is over!"); %V&I${z  
bDownOver = true; d?_LNSDo  
//nPos = fileAccessI.write (b,0,nRead); jt
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} LwL\CE_6+  
catch(Exception e){e.printStackTrace ();} 0nO
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} =gb(<`{>  
} [J6b5  
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//打印回应的头信息 BL Q&VI4  
public void logResponseHead(HttpURLConnection con) mbm|~UwD  
{ ;%tu;  
for(int i=1;;i++) :\+\/H
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{ oy!Dm4F  
String header=con.getHeaderFieldKey(i); %/(>>*}Kw|  
if(header!=null) \r+8}8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); G oJ\6&"  
Utility.log(header+" : "+con.getHeaderField(header)); bu|ecv  
else sBfPhBT|  
break; Ap[}[:U  
} qmJ^@dxs  
} 5{uK;Vxse  
' y9yx[P  
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public void splitterStop() b!ea(D!:  
{ 6bW:&IPQ;  
bStop = true; r=3knCEWK  
} @JL+xfz  
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} =P.m5e<  
{Z=m5Dy}  
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/* _^)<d$R<  
**FileAccess.java 6Wabw:  
*//文件访问(定位，写) Sn lKPd  
package NetFox; @^';[P!  
import java.io.*; HRY?[+  
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/\_wDi+#  
public class FileAccessI implements Serializable{ *NDM{WB|)  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ka"Z,\T   
RandomAccessFile oSavedFile; o?$
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long nPos; &4ScwK:  
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public FileAccessI() throws IOException 0H-~-z8Y  
{ {LLy4m  
this("",0); KiJRq>  
} M9/c8zZ  
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public FileAccessI(String sName,long nPos) throws IOException :2KLziO2  
{ >_4Ck{^d#  
oSavedFile = new RandomAccessFile(sName,"rw"); ?
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this.nPos = nPos; u0@i3Po  
oSavedFile.seek(nPos); ZE*m;  
} PmGW\E[ni  
z|
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public synchronized int write(byte[] b,int nStart,int nLen) Q6G-`&5  
{ 2h6<'2'o1  
int n = -1; @L-3&~=  
try{ O,kzU,zOs  
oSavedFile.write(b,nStart,nLen); 6eqPaIaD   
n = nLen; 9N[PZD  
} hK,e<?N^  
catch(IOException e) m"<Sb,"x!  
{ ORV~F0d<  
e.printStackTrace (); SJtQK-%wK>  
} |@x^5Ab$T  
0 7CufoI  
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return n; {1Z`'.FU  
} $EB&]t+  
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V #0F2GV<,  
} Y?(kE` R  
e `!PQMLU  
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/* XA~Cc<v  
**SiteInfoBean.java TU
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*/ w(QU'4~  
package NetFox; v>FsP$p4yE  
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public class SiteInfoBean { hlpi-oW`  
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private String sSiteURL; //Site's URL BitP?6KX  
private String sFilePath; //Saved File's Path 0^41dfdE  
private String sFileName; //Saved File's Name v)*/E'Cr*  
private int nSplitter; //Count of Splited Downloading File /Q4TQ\:  
.Vm!Ng )j  
b]'Uv8fbF  
public SiteInfoBean() Fb&Xy{kt1  
{//nSplitter的缺省值为5 uT'}_2=:  
//default value of nSplitter is 5 42a.@JbLQ  
this("","","",5); y9cDPwi:b  
} d{cd+An  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &@tD/Jw3  
{ 4l/hh|3@  
sSiteURL= sURL; Yv?nw-HM  
sFilePath = sPath;
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sFileName = sName; -}u=tiNG  
this.nSplitter = nSpiltter; e>zCzKK  
h0}=C_.^  
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} ~)\9f 1O{^  
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public String getSSiteURL() u@
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{ YP*EDb?f  
return sSiteURL; S VCTiG8t  
} d5zv8?|X+  
[{]/9E/&  
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public void setSSiteURL(String value) T5* t~`bfU  
{ x=1Iuc;&3  
sSiteURL = value; O$F<x,  
} b@G
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public String getSFilePath() !GB\-(  
{ :
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return sFilePath; &I8Q'  
} d']CBoK  
)
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public void setSFilePath(String value) mGss9eZa  
{ ]q#w97BxiJ  
sFilePath = value; MIV<"A  
} g+g0iS  
.[%
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public String getSFileName() R^v-%mG9  
{ ]]sy+$@~  
return sFileName; `^:>sU  
} r#8t@W  
1 u[a713O  
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public void setSFileName(String value) P
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{
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sFileName = value; 54X=58Q  
} *$%ch=  
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public int getNSplitter() CcGE4BB  
{ sBN"eHg  
return nSplitter; QcW6o,  
} , %8keGhl  
kGz0`8URu  
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public void setNSplitter(int nCount) O4)'78ATp  
{ }u3Q*oAGl  
nSplitter = nCount; ; 9n}P@  
} %4bGI/\/  
} z%FBHj  
Z<P
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|M8FMH[_  
/* ;u:A:Y4V  
**Utility.java L1Hk[j]X|  
*/
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package NetFox; o\TXWqt  
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 $,b1`*  
public class Utility { g1!ek  
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public Utility() Q1Jw7R#?l  
{ "b~-`ni  
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} 1<9=J`(H  
b0(bL_,  
//线程睡眠 `>HM<Nn-0  
public static void sleep(int nSecond) @IXvp3r  
{ j3-^,r t4  
try{ sYfiC`9SO  
Thread.sleep(nSecond); **,(>4j  
} 0Z.X;1=  
catch(Exception e) MH0xD  
{ O:%,.??<%  
e.printStackTrace (); q0m>NA   
} b] EC+.  
} {)CN.z:O  
T{CCZ"Fv  
//日志 ydZS^BqG  
public static void log(String sMsg) iQT$#"m n  
{ n<)gS7  
System.err.println(sMsg); yQ [n7du  
} )yl
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M?g
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public static void log(int sMsg) <MQTOz oj  
{ 6

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System.err.println(sMsg); su}n3NsJ  
} -$2B!#]3
 
} C j4ED  
'NAC4to;;  
}J^+66{  
/* ^~7/hm:  
**TestMethod.java j^T i6F>f  
*/ r%uka5@  
package NetFox; 7l+:gD  
+Oafo|%  
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public class TestMethod { `Eg~;E:  
.T\jEH8E  
,hVDGif  
public TestMethod() NMvNw?]
 
{ ///xx/weblogic60b2_win.exe d#U~
>wr  
try{ kSfNu{YS  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %wQE lkB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N<N uBtkA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9F"^MzZ  
fileFetch.start(); xTGdh  
} PK&\pkX  
catch(Exception e){e.printStackTrace ();} 4(D1/8  
<*3#nA-O>i  
'}, 8x?  
} PKg>|]Rf.  
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public static void main(String[] args) Q`zW[Y&]  
{ Gl6M(<f\5  
new TestMethod(); VBN=xg}  
} <hBd #J  
} dcH@$D@~S  
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