http断点续传简单实现（java)

/* 3,-[lG@o  
**SiteFileFetch.java #mkf2Z=t-  
*/ MUSsanCA  
package NetFox; Q89fXi0Ivb  
import java.io.*; Z)md]Twt  
import java.net.*; < n/ 2  
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public class SiteFileFetch extends Thread { ~*x 2IPiH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~G 3t
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long[] nStartPos; //开始位置 9BAvE\o0  
long[] nEndPos; //结束位置 o59b#9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 KwU;+=_.  
long nFileLength; //文件长度 SEVB.;  
boolean bFirst = true; //是否第一次取文件 \440gH`  
boolean bStop = false; //停止标志 h"nhDART<  
File tmpFile; //文件下载的临时信息 K&eT*JW>  
DataOutputStream output; //输出到文件的输出流 aYn5AP'PH  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2T(7V[C%9  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4:5M,p  
{ )qe rA  
siteInfoBean = bean; xpc{#/Nk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yD#(Iw  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Cz &3=),G  
if(tmpFile.exists ()) :
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{ t YxN^VqU  
bFirst = false; O_]hbXV0  
read_nPos(); B
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} zK&1ti@wln  
else ,3N>`]Km'  
{ d0-4
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nStartPos = new long[bean.getNSplitter()]; *2pf>UzL  
nEndPos = new long[bean.getNSplitter()]; CK1A$$gnz  
} uehu\umt=  
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} Vl;zd=  
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public void run() #ID fJ2  
{ *jvP4Nz)k  
//获得文件长度 |1zfXG,R  
//分割文件 ]6M,s0  
//实例FileSplitterFetch @yo6w}3+-  
//启动FileSplitterFetch线程 @<`V q  
//等待子线程返回 Lq;T\m_de  
try{ JOJuGB-d  
if(bFirst) fp*6Dv_  
{ *ow`}Q  
nFileLength = getFileSize(); n}t9Nf_  
if(nFileLength == -1) .]s? 01Z  
{ b$yIM  
System.err.println("File Length is not known!"); -DK6(<:0  
} *V7mM?  
else if(nFileLength == -2) Yxbg _RQm  
{ T*%rhnTv0  
System.err.println("File is not access!"); O-[  
} "{\xBX~oM  
else Je,o(:  
{ +80bG(I_  
for(int i=0;i<nStartPos.length;i++) P;o{t  
{ JsNj!aeU%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qS9<_if2  
} D'vaK89\  
for(int i=0;i<nEndPos.length-1;i++) 7B=VH r  
{ :;eQ*{ `\  
nEndPos = nStartPos[i+1]; W
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} T0Xm}i  
nEndPos[nEndPos.length-1] = nFileLength; ;i\N!T{>  
} ^2);*X>  
} GcDA0%i  

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n}_}#(a  
//启动子线程 Rk7F;2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .{\eco  
for(int i=0;i<nStartPos.length;i++) qdn_ZE  
{ xT]t3'y|-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lg8@^Pm$r;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /]^Y\U^  
nStartPos,nEndPos,i); ^C1LQZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ge(,>xB  
fileSplitterFetch.start(); 1G7l+6w5~^  
} Kei0>hBi  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sOlnc6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &l3(+4Sh  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?_d6;  
nEndPos = " + nFileLength); w;yzgj:n&f  
// fileSplitterFetch[nPos.length-1].start(); R~T}  
_dRB=bl"O  
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//等待子线程结束 G{]RC^Zo  
//int count = 0; Jx~H4y=z  
//是否结束while循环 jLM([t  
boolean breakWhile = false; l)*(UZ"  
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while(!bStop) ZnRT$ l O  
{ *Z^`H!&  
write_nPos(); A&)2m  
Utility.sleep(500); }oA>0Nw$K  
breakWhile = true; )WbWp4  
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for(int i=0;i<nStartPos.length;i++) tE_n>~Zs  
{ ;cvMNU$fN  
if(!fileSplitterFetch.bDownOver) | bRU=dg  
{ [K$5Rm5  
breakWhile = false;  $8rnf  
break; IHdA2d?.]  
} ,|s*g'u  
} A5J41yH  
if(breakWhile) v}N\z2A  
break; r'jUB^E  
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"WuUMt  
//count++; cI'n[G  
//if(count>4) xi(1H1KN5B  
// siteStop(); 'fl< ac,.  
} 9D+k71"+  
$

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 ?bVIH?  
System.err.println("文件下载结束！"); n|)((W  
} %K4M`R|2]  
catch(Exception e){e.printStackTrace ();} R|$AcNp  
} p|.5;)%|  
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//获得文件长度 mf$YsvPq*+  
public long getFileSize() Mq)]2>"v  
{ (87| :{  
int nFileLength = -1; RW+
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try{ I51]+gEN  
URL url = new URL(siteInfoBean.getSSiteURL()); :Q>e54]'&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p$9Aadi]  
httpConnection.setRequestProperty("User-Agent","NetFox"); / Qd` ?  
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int responseCode=httpConnection.getResponseCode(); '0+~]4&}q  
if(responseCode>=400) pQBn8H|Y  
{ tngB;9c+w  
processErrorCode(responseCode); n}.e(z_"  
return -2; //-2 represent access is error Hs'~)
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} gAWi&  
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String sHeader; 9>w~B|/  
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for(int i=1;;i++) W&Fm;m@M  
{ 9
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a%B&F|u  
//Utility.log(in.readLine()); '~&W'='b;  
sHeader=httpConnection.getHeaderFieldKey(i);
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if(sHeader!=null) 6whPW .  
{ ?iP7Ki  
if(sHeader.equals("Content-Length")) Pgr2S I  
{ (T#$0
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); qisvGHo  
break; AJ7^'p9Y  
} xyL)'C  
} B#S8j18M  
else h'-4nu;*  
break; 8C@u+tx  
} *
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} >|A,rE^Ojt  
catch(IOException e){e.printStackTrace ();} S[3"?$3S  
catch(Exception e){e.printStackTrace ();} W
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Utility.log(nFileLength); "jum*<QZz  
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return nFileLength; 6]b"n'G  
} Gy/w #4xj  
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" _2k3  
//保存下载信息（文件指针位置） T<pG$4_  
private void write_nPos() w-pgtO|Us  
{ ce\d35x!  
try{ !6'N-b1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Dhn7N8(LF!  
output.writeInt(nStartPos.length); 4-.K<-T%D  
for(int i=0;i<nStartPos.length;i++) b!@PS$BTxq  
{
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// output.writeLong(nPos); HXa[0VOx  
output.writeLong(fileSplitterFetch.nStartPos); .g*N+T6O  
output.writeLong(fileSplitterFetch.nEndPos); X>[i<ei  
} B>L7UQ6_[  
output.close(); gU
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} {1OxJn1hd  
catch(IOException e){e.printStackTrace ();} $o?U=  
catch(Exception e){e.printStackTrace ();} Dm}eX:'{  
} ^<OYW|q?\r  
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//读取保存的下载信息（文件指针位置） JLE&nbKS  
private void read_nPos() =NtHV4=b  
{ s
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try{ ;
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Wn=sF,c  
int nCount = input.readInt(); &" t~d}Rg  
nStartPos = new long[nCount]; w.
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nEndPos = new long[nCount]; L5FOlzn  
for(int i=0;i<nStartPos.length;i++) [_'A(.  
{ 6#+&/ "*  
nStartPos = input.readLong(); 9Y,JYc#  
nEndPos = input.readLong(); ~JXz  
} 2xLtJR4L  
input.close(); cb9-~*1  
} ?.VKVTX^  
catch(IOException e){e.printStackTrace ();} _cs(f<>oCO  
catch(Exception e){e.printStackTrace ();} T o["o!(;z  
} M(I%y0  
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private void processErrorCode(int nErrorCode) juOStTq<  
{ R!j#  
System.err.println("Error Code : " + nErrorCode); OZxJDg  
} >)ekb7  
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//停止文件下载 *<xu3){:c  
public void siteStop() Qfm$q~`D^W  
{ "@nH;Xlq  
bStop = true; 4?+K `  
for(int i=0;i<nStartPos.length;i++) -"I$$C  
fileSplitterFetch.splitterStop(); jhm3:;Z  
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} @Ul3J )=m  
} MQ!4"E5"j  
//负责部分文件的抓取 epiviCYC  
**FileSplitterFetch.java B"&-) (  
*/ :8)Jnh\5  
package NetFox; 'v]0;~\mp>  
#BLHHK/[  
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import java.io.*; .|O T#"LP  
import java.net.*; /qIQE&V-  
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public class FileSplitterFetch extends Thread { eC!=4_lx)  
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String sURL; //File URL 0zH-g  
long nStartPos; //File Snippet Start Position R
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long nEndPos; //File Snippet End Position -MTk9<qnT  
int nThreadID; //Thread's ID F$as#.7FF  
boolean bDownOver = false; //Downing is over X hq ss),  
boolean bStop = false; //Stop identical H@uu;:l<7A  
FileAccessI fileAccessI = null; //File Access interface w6V/Xp][U  
;|Mfq`s  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y47N(;vy  
{ \V$qAfP)  
this.sURL = sURL; _Xd"'cXw  
this.nStartPos = nStart; \}jA1oy  
this.nEndPos = nEnd; A]|w1nq  
nThreadID = id; O-V|=t  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 a}%f+`z  
} sq2:yt  
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public void run() sQ}|Lu9hZ  
{ vu+g65"  
while(nStartPos < nEndPos && !bStop) hBX*02p  
{ M3jUnp&  
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try{ ZHNL~=r}  
URL url = new URL(sURL); |P>
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,MXU]{  
httpConnection.setRequestProperty("User-Agent","NetFox"); T<B}Z11R  
String sProperty = "bytes="+nStartPos+"-"; 4QA~@pBX^{  
httpConnection.setRequestProperty("RANGE",sProperty); !_
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Utility.log(sProperty); s/7Z.\  
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InputStream input = httpConnection.getInputStream(); @[g7\d  
//logResponseHead(httpConnection); 3jAr"xc  
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byte[] b = new byte[1024]; iO$87!  
int nRead; ~M}{rl.n=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }b\hRy~=r  
{ "-=fi 'D  
nStartPos += fileAccessI.write(b,0,nRead); =Dq&lm,n  
//if(nThreadID == 1) ^m#tWb)f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T[SK>z  
}
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*S}@DoXS  
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Utility.log("Thread " + nThreadID + " is over!"); OIPY,cj~  
bDownOver = true; x-[ItJ% l  
//nPos = fileAccessI.write (b,0,nRead); hS,&Nj+  
} 1sHjM%  
catch(Exception e){e.printStackTrace ();} hoq2zDjD  
} c& ;@i$X(  
} D6L+mTN  
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//打印回应的头信息 HEVjK$  
public void logResponseHead(HttpURLConnection con) "Wj{+|f  
{ w^0hVrws=,  
for(int i=1;;i++) u+j\PWOtm  
{ "9_$7.q<y  
String header=con.getHeaderFieldKey(i); 3:iEt (iCI  
if(header!=null) S"&Gutu3o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >`AK'K8{M  
Utility.log(header+" : "+con.getHeaderField(header)); ~2Wus8X-  
else )
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break; p3A9<g  
} LFax$CZ
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} 3Z?ornS  
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public void splitterStop() {5Bj*m5  
{ q}t]lD %C  
bStop = true; bo|THS  
} LTe ({6l0  
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} #^L&H oo6  
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0#WN2f, <:  
/* ?b+Y])SJK  
**FileAccess.java ~P'.R.e  
*//文件访问(定位，写) h^ Cm
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package NetFox; )g'J'_Sl  
import java.io.*; V*@aE  
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public class FileAccessI implements Serializable{ zcP=+Y)YA  
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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 _8.TPB]n
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RandomAccessFile oSavedFile; |#_p0yPy  
long nPos; w x]?D%l  
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public FileAccessI() throws IOException Z+v,o1  
{ `^[k8Z(  
this("",0); A;L ]=J  
} N~,Ipf  
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public FileAccessI(String sName,long nPos) throws IOException ui>jJ(  
{ Kzrd<h]`)  
oSavedFile = new RandomAccessFile(sName,"rw"); uP* kvi:e  
this.nPos = nPos; &b|Ro
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oSavedFile.seek(nPos); vQ}ZfP  
} x#`p.sfVo  
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public synchronized int write(byte[] b,int nStart,int nLen) [_JdV(]$  
{ vi}16V84l  
int n = -1; *<sc[..)  
try{ ~pZ0B#K J  
oSavedFile.write(b,nStart,nLen); &{? M} 2I  
n = nLen; sbmtx/%U  
} kU/MvoV  
catch(IOException e) WJD2(el  
{ jQV[zcM  
e.printStackTrace (); p9)YRLOh.  
} Q/SO%E`E  
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return n; e8<}{N0,n  
} S a
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} Aars\   
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/* "<=4]Z  
**SiteInfoBean.java 59zWB,y(P  
*/ a=}1`Q  
package NetFox; /ugWl99.W  
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public class SiteInfoBean { GKFRZWXdT  
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private String sSiteURL; //Site's URL nod&^%O"  
private String sFilePath; //Saved File's Path rci,&>L"  
private String sFileName; //Saved File's Name +%XByY5  
private int nSplitter; //Count of Splited Downloading File 1Rd|P<y  
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public SiteInfoBean() Z5'^81m$o  
{//nSplitter的缺省值为5 ~ L4NK#  
//default value of nSplitter is 5 yzK<yvN  
this("","","",5); %Lh%bqGz  
}  ijOp{  
, ~ 1+MZ=  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) q%x i>H.:{  
{ 4m<]qw
 
sSiteURL= sURL;  skl3/!  
sFilePath = sPath; vS
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sFileName = sName; d3q%[[@  
this.nSplitter = nSpiltter; xmnBG4,f  
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} dXxf{|gk>  
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public String getSSiteURL() c~tl0XU1  
{ ZRf9'UwS  
return sSiteURL; u~OlJ1V  
} T!,5dt8L  
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public void setSSiteURL(String value) =W7-;&  
{ gfK_g)'2U  
sSiteURL = value; +\Vw:
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} h"ZIh= j@  
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public String getSFilePath() =J1V?x=l@  
{ pK-tj  
return sFilePath; z@VL?A(3  
} x[lIib
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public void setSFilePath(String value) `n>|rd  
{ \'Ca1[y@B  
sFilePath = value; sAc1t`  
} lPR^~&
/  
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i@+m<YS:2>  
public String getSFileName() )tBz=hy#  
{ =u}~\ 'd  
return sFileName; +A8q.-N G  
} .T7CMkYt  
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public void setSFileName(String value) FQ0&{ulb  
{ A4,%l\di<  
sFileName = value; BlpyE[h T  
} J
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5,,'hAq_  
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public int getNSplitter() bK6^<,~  
{ 6MM\nIU)/  
return nSplitter; vk E]$4P[$  
} i&H^xgm  
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public void setNSplitter(int nCount) ifS#9N|8  
{ %JDQ[%3qY  
nSplitter = nCount; ynw(wSH=  
} =)Hu
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} nam]eW  
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/* m4~
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**Utility.java '1DY5`i{  
*/ Mlc_w19C9  
package NetFox; HTQTDbhV^  
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public class Utility { :=*G7ZyW$  
}< '6FxR  
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public Utility() H<!q@E ;  
{ gOnZ#  
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} w-JWMgY8w  
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//线程睡眠 Ba
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public static void sleep(int nSecond) ! $mY.uu  
{ gpyio1V>  
try{ !2Ompcr1  
Thread.sleep(nSecond); 6IRRRtO(  
} =c\(]xX  
catch(Exception e) 1
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{ I(7GVYM  
e.printStackTrace (); 4G:~|N.{p  
} 6h5g!GQD  
} P7W|e~]Yq  
@_"cMU!  
//日志 ?ch?q~e)  
public static void log(String sMsg) ,{G\-(\  
{ <gi~:%T  
System.err.println(sMsg); , poc!n//  
}
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public static void log(int sMsg) ?J
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{ z59;Qk  
System.err.println(sMsg); h0m5oV  
} |WS@q'
  
} j~Fd8]@  
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@ NDcO,]  
/* b]?5r)GK  
**TestMethod.java e8f7*S8  
*/ &Y@),S9  
package NetFox; 075IW"p'  
+}at#%1@  
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public class TestMethod { * G*VY#L  
p@q20>^u  
o=94H7@  
public TestMethod() c}$>UhLe  
{ ///xx/weblogic60b2_win.exe 2HVqJib4Yn  
try{ 03)irq%l;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); rD$5]%Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Zs}h>$E5_B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2{WZ?H93a  
fileFetch.start(); vv)w@A:Vn)  
} y|BHSc3  
catch(Exception e){e.printStackTrace ();} uPcx6X3]  
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} |FT.x9e-  
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public static void main(String[] args) U) xeta+  
{ %!-t7K^mFq  
new TestMethod(); k>MXOUaW.  
} jqvw<+#  
} L-U4 8 i  
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