http断点续传简单实现（java)

/* L@?3E`4/v  
**SiteFileFetch.java }P\6}
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*/ D mky!Cp
 
package NetFox; rzvKvGd#N  
import java.io.*; HRCnjem/v\  
import java.net.*; \0e`sOS`L  
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public class SiteFileFetch extends Thread { e)XnS'  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2^rJ|Ni  
long[] nStartPos; //开始位置 r{*BJi.b  
long[] nEndPos; //结束位置 r'o378]=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rJRg4Rog  
long nFileLength; //文件长度 7y.iXe!P  
boolean bFirst = true; //是否第一次取文件 Qf'g2 \  
boolean bStop = false; //停止标志 z'"Y+EWN  
File tmpFile; //文件下载的临时信息 )$d~HA@B  
DataOutputStream output; //输出到文件的输出流 H_aG\  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） k7cY^&o  
public SiteFileFetch(SiteInfoBean bean) throws IOException V"}Jsr  
{ K7nyQGS  
siteInfoBean = bean; <zAYq=IU  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }O| 9Qb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M0KU}h  
if(tmpFile.exists ()) #nAq~@X  
{ [r'A8!/|[  
bFirst = false; h[<l2fy  
read_nPos(); H4sc7-  
} VC%.u.< F  
else o-;/x)  
{ !DF5NAE  
nStartPos = new long[bean.getNSplitter()]; IcGX~zWr  
nEndPos = new long[bean.getNSplitter()]; lWT`y  
} ,@Kn@%?$  
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} aeAx0yE[p  
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public void run() f$vTDak  
{ 9jM7z/Ff  
//获得文件长度 1i'y0]f  
//分割文件 l\uNh~\  
//实例FileSplitterFetch uU^iY$w  
//启动FileSplitterFetch线程 5}Xi`'g,  
//等待子线程返回 O}p<"3Ub  
try{ ;Me*#/  
if(bFirst) Fop +xR,Z  
{ 0r8Wv,7Bo  
nFileLength = getFileSize(); tV>qV\>  
if(nFileLength == -1) 9\/oL{  
{ DH.UJ+  
System.err.println("File Length is not known!"); K>b4(^lf  
} 5C^@w
 
else if(nFileLength == -2) 9
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{ nAAv42j[  
System.err.println("File is not access!"); P8ZmrtQm  
} x{tlC}t  
else 2gMG7%d  
{ %~gI+0HK  
for(int i=0;i<nStartPos.length;i++) Id>4fF:o  
{ ;gD\JA  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Xtz:^tg  
} 5,g +OY=\  
for(int i=0;i<nEndPos.length-1;i++) oD1k7Gq1  
{ ,]W|"NUI  
nEndPos = nStartPos[i+1]; 2lOUNxQ$  
} /]MelW  
nEndPos[nEndPos.length-1] = nFileLength; />/e  
} w>=N~0@t  
} G9yK/g&q  
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//启动子线程 +*?l">?|F  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 
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for(int i=0;i<nStartPos.length;i++) ^2+Vt=*  
{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '?L^Fa_H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), r~ 2*'zB  
nStartPos,nEndPos,i); EG\;l9T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >7%T%2N  
fileSplitterFetch.start(); vc&+qI+I3  
} V|$PO Qa3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6[c|14l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); R_KDY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >RAg63!`  
nEndPos = " + nFileLength); Y%;X7VxU*  
// fileSplitterFetch[nPos.length-1].start(); 1BZ##xV*:G  
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'5De1K.\`  
//等待子线程结束 h\w;SDwOk  
//int count = 0; 7Y(Dg`8G  
//是否结束while循环 e'G=.:
 
boolean breakWhile = false; UGy3B)  
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while(!bStop) R^o535pozc  
{ rxu_Ssd@"  
write_nPos(); ~io.TS|r  
Utility.sleep(500);
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breakWhile = true; `?(J(H  
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for(int i=0;i<nStartPos.length;i++) v#%rjml[  
{ vxEi C:&]  
if(!fileSplitterFetch.bDownOver) (4/"uj5  
{ xsj,l@Ey  
breakWhile = false; ~rdS#f&R2  
break;
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} \EVT*v=}/  
} S W%>8  
if(breakWhile) PKrG6% W+  
break; >*ls} q^  
} u;{38~  
v.Bwg7R3  
//count++; )2?]c  
//if(count>4) 
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// siteStop(); V=8db%^  
} AYfOETz  
z:f&k}(  
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System.err.println("文件下载结束！"); '2lzMc>wvP  
} *P=3Pl?j  
catch(Exception e){e.printStackTrace ();} ~iH a^i?2*  
} |> STb\  
MSS[-}  
-@(LN%7
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//获得文件长度 yO)xN=o^\  
public long getFileSize() auK9wQ%\  
{ zFm`e:td  
int nFileLength = -1; 6I"KomJ9  
try{ PzSLE>Q  
URL url = new URL(siteInfoBean.getSSiteURL()); #U`AK9rP_g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u.X]K:Yow  
httpConnection.setRequestProperty("User-Agent","NetFox"); |hika`35K  
jSE)&K4nI  
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int responseCode=httpConnection.getResponseCode(); Lf5zHUH  
if(responseCode>=400) P".}Y[GD  
{ R
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processErrorCode(responseCode); MN2i0!+  
return -2; //-2 represent access is error 1}wDc$O  
} c%pf,sm'  
'/8/M{`s  
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String sHeader; %oa@2qJ^  
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for(int i=1;;i++) L3Y,z3/  
{ jI\@<6
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o@L0ET  
//Utility.log(in.readLine()); ; H ;h[
 
sHeader=httpConnection.getHeaderFieldKey(i); }X{rE|@  
if(sHeader!=null) Zu|NF uFI  
{ h}SZ+G/L  
if(sHeader.equals("Content-Length")) $XQgat@&]  
{ zG_nx3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); G7&TMg7i  
break; ZXb|3|D  
} {`SMxDevc}  
} 9DA|;|  
else 6m?<"y8]  
break; ys=} V|  
} [Kc?<3W  
} DehjV6t  
catch(IOException e){e.printStackTrace ();} nIg 88*6b,  
catch(Exception e){e.printStackTrace ();} MBt\"b#t  
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Utility.log(nFileLength); f9K7^qwkiz  
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return nFileLength; ~o_JZ:  
} *S*49Hq7c  
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^ELZ35=qZ  
//保存下载信息（文件指针位置） *90dkJZ.  
private void write_nPos() 
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{ =?C <@  
try{ } TUr96  
output = new DataOutputStream(new FileOutputStream(tmpFile)); op`9(=DJ]  
output.writeInt(nStartPos.length); y]yl7g =~  
for(int i=0;i<nStartPos.length;i++) FcM)v"bF&]  
{ SWzqCF  
// output.writeLong(nPos); %@C8EFl%3  
output.writeLong(fileSplitterFetch.nStartPos); 2*75*EQCH  
output.writeLong(fileSplitterFetch.nEndPos); H]tD~KM<  
} d\>XfS  
output.close(); m?Y-1!E0  
} j?u1\
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catch(IOException e){e.printStackTrace ();} V$hL\`e  
catch(Exception e){e.printStackTrace ();} j
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} 8i[TeW"  
[
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//读取保存的下载信息（文件指针位置） RI8*'~ix]  
private void read_nPos() z` 6$p1U  
{ q`p0ul,n  
try{ 5!A:xV]6]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Fb1<Ic#  
int nCount = input.readInt(); 1,=:an  
nStartPos = new long[nCount]; 2 %fcDEG/  
nEndPos = new long[nCount]; ,Gv}N&  
for(int i=0;i<nStartPos.length;i++) ?n{m2.H  
{ #EUT"^:d  
nStartPos = input.readLong(); 424iFc[  
nEndPos = input.readLong(); NB<8M!X/  
} l/(~Kf9eQG  
input.close(); YZfi-35@g  
} =SmU;t>t/  
catch(IOException e){e.printStackTrace ();} * ;sz/.  
catch(Exception e){e.printStackTrace ();} g8E5"jpXx3  
} V/xXW
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private void processErrorCode(int nErrorCode) j_,/U^Ws|f  
{ [nHN@p|  
System.err.println("Error Code : " + nErrorCode); <m
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} JJ1>)S}X-  
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//停止文件下载 sHPAr}14  
public void siteStop() %|+aI?  
{ zf)*W#+  
bStop = true; e=h-}XRC  
for(int i=0;i<nStartPos.length;i++) L44|/~  
fileSplitterFetch.splitterStop(); tYTl-c  
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} 
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} ^! h3#4  
//负责部分文件的抓取 qGN>a[D  
**FileSplitterFetch.java 4_>;|2  
*/ pvl];w  
package NetFox; I-8I/RRkmP  
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import java.io.*; ';\norx;  
import java.net.*; 4/{pz$  
:55a9d1bL  
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public class FileSplitterFetch extends Thread { 6K7lQ!#}Q  
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String sURL; //File URL lAG@nh^  
long nStartPos; //File Snippet Start Position 8(- 29  
long nEndPos; //File Snippet End Position WU=EJY}#n  
int nThreadID; //Thread's ID kLF3s#k  
boolean bDownOver = false; //Downing is over j0oto
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boolean bStop = false; //Stop identical UxB3/!<5g3  
FileAccessI fileAccessI = null; //File Access interface 5`&@3 m9/  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,>qtnwvlHP  
{ tUJe-3,  
this.sURL = sURL; qp*~|  
this.nStartPos = nStart; %&H^UxC  
this.nEndPos = nEnd; 7Q'u>o  
nThreadID = id; mHW%^R=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _7u&.l<;  
} ?HOnDw.v1  
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public void run() pHoxw|'Y  
{ &)Zv>P8z`  
while(nStartPos < nEndPos && !bStop) ;D-k\kv  
{ UWqiA`,  
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try{ AK'3N1l`  
URL url = new URL(sURL); ]fh(b)8_,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); * #z@b  
httpConnection.setRequestProperty("User-Agent","NetFox"); sm[zE/2b  
String sProperty = "bytes="+nStartPos+"-"; 5>e<|@2 X  
httpConnection.setRequestProperty("RANGE",sProperty); {Z
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Utility.log(sProperty); 45Zh8k  
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\%}]wf}  
InputStream input = httpConnection.getInputStream(); w .M  
//logResponseHead(httpConnection); hWn-[w/l_  
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byte[] b = new byte[1024]; pFu!$.Fr  
int nRead; d7&d FvG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Z6WNMQ1:  
{ [*C~
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nStartPos += fileAccessI.write(b,0,nRead); vz:VegS  
//if(nThreadID == 1) EN}4-P/
5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zw5Ol%JF  
} })PU`?f  
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Utility.log("Thread " + nThreadID + " is over!"); >*^SQ
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bDownOver = true; PRyzvc~  
//nPos = fileAccessI.write (b,0,nRead); x=\W TC  
} tk 5p@l  
catch(Exception e){e.printStackTrace ();} ?vik2RW  
} Sy*p6DP  
} ;3Z?MQe"NQ  
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//打印回应的头信息 j@UE#I|h  
public void logResponseHead(HttpURLConnection con) W=HHTvK9Hh  
{ p]s)Xys  
for(int i=1;;i++) ~
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{ x],XiSyp  
String header=con.getHeaderFieldKey(i); (v0Q.Q@<  
if(header!=null) )C0Iy.N-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r0\C2g_X  
Utility.log(header+" : "+con.getHeaderField(header)); $.ctlWS8l{  
else XVKRT7U  
break; ,x3<a}J  
} @6;ZP1  
} Kb/qM}jS  
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public void splitterStop() Z#kB+.U  
{ %_39Wa  
bStop = true; \2Q#'  
} B\ZCJaMb  
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} 8&1xb@Nc7  
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/* GJF ,w{J  
**FileAccess.java a]8W32  
*//文件访问(定位，写) 6jov8GIAt  
package NetFox; 9`&sZ|"3  
import java.io.*; 1:{+{Yl7  
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public class FileAccessI implements Serializable{ {s2eOL5I|%  
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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 c11;(  
RandomAccessFile oSavedFile; K@"B^f0mU  
long nPos; $?OQtz@  
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public FileAccessI() throws IOException ,K.W
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{ JUq7R%"h6  
this("",0); ndvt $*  
} 5E${  
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public FileAccessI(String sName,long nPos) throws IOException 8b25D|8l  
{ 8'Q&FW3"  
oSavedFile = new RandomAccessFile(sName,"rw"); dZCjg0cx  
this.nPos = nPos; _6aI>b#yL  
oSavedFile.seek(nPos); C&.Q|S2_  
} 2FN#63  
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public synchronized int write(byte[] b,int nStart,int nLen) \.=,}sV2Z  
{ lQ2vQz-J  
int n = -1; Ol8Yf.e_  
try{ W;F=7[h  
oSavedFile.write(b,nStart,nLen); @3?dI@i(  
n = nLen; "OrF81  
} h0-CTPQ7A  
catch(IOException e) X/
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{ O7f"8|=HX  
e.printStackTrace (); 8?hj}}H  
} cM=_i{c  
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return n; 'D^@e0.3  
} Tq
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} ~mT([V  
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/* ;Hu`BFXyD  
**SiteInfoBean.java Shu=oweJ  
*/ cXt]55"  
package NetFox; }t1J`+x%  
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public class SiteInfoBean { }`_x%]EJ  
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private String sSiteURL; //Site's URL D|/ 4
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private String sFilePath; //Saved File's Path AN+S6t  
private String sFileName; //Saved File's Name %WFZ&>en&  
private int nSplitter; //Count of Splited Downloading File x#'v}(v  
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public SiteInfoBean() ,BlNj^5f  
{//nSplitter的缺省值为5 A7aW]  
//default value of nSplitter is 5 [f`7+RHrd  
this("","","",5); 'I@l$H  
} {br6*  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p

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{ EskD)Sl  
sSiteURL= sURL; w*gG1BV  
sFilePath = sPath; g<YN#  
sFileName = sName; .-cx9&  
this.nSplitter = nSpiltter; Vv*](iM  
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} {w<"jw&2  
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public String getSSiteURL() 6rN.)dL.#N  
{ {,e-;2q  
return sSiteURL; fmv,)UP  
} noO#o+ Jg#  
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public void setSSiteURL(String value) Pk&sY'  
{ Gw+pjSJL`  
sSiteURL = value; !
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} *fQn!2}=(  
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public String getSFilePath() c2fw;)j&X  
{ PySFhb@  
return sFilePath; F+<Z%KuCu  
} Zo}vV2  
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public void setSFilePath(String value) Ceew~n{  
{ [rReBgV  
sFilePath = value; +3]V>Mv  
} ;e6-*  
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public String getSFileName() ^n*:zmD  
{ /&zlC{:G92  
return sFileName; 
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} z+<ofZ(.  
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public void setSFileName(String value) qI*7ToBJ  
{ ku
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sFileName = value; _,3%)sn-)  
} =Js
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public int getNSplitter() uj+{ tc  
{ JV?
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return nSplitter; Op
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} Av!xI  
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public void setNSplitter(int nCount) XT1P. w[aA  
{ x|)pZa  
nSplitter = nCount; |qpFR)l  
} DC0ON`  
} W#\{[o  
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/* FmgMd)#  
**Utility.java yYdh+x  
*/ eu'~(_2  
package NetFox; !\cVe;<r  
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public class Utility { g!^mewtd  
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public Utility() . Ctd$  
{ +'_ peT.8  
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} ,P=.x%  
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//线程睡眠 9+ |W;  
public static void sleep(int nSecond) t:b}Mo0  
{ @WiTh'w0  
try{ 4vV\vXT*  
Thread.sleep(nSecond); \i\>$'f*z  
} IkO[R1K  
catch(Exception e) tJmy}.t1  
{ [~c_Aa+6N  
e.printStackTrace (); ).-#  
} E6M*o+Y  
} 9 9^7Ek!z#  
3#y`6e=5  
//日志 (LJ7xoJ^  
public static void log(String sMsg) >< VUly  
{ rV} 5&N*c  
System.err.println(sMsg); 3*\hGt,ZP  
} (G(M"S SC  
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public static void log(int sMsg) #g'j0N  
{ R7O<>kt  
System.err.println(sMsg); ;aD?BD__Z  
} FR>[g`1  
} c6AwO?x/  
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/* yPg0:o-  
**TestMethod.java J%T=FU  
*/ 1/&^~'  
package NetFox; p<?lF  
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s_^N=3Si   
public class TestMethod { &N]e pV>  
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public TestMethod() \DWKG~r-%  
{ ///xx/weblogic60b2_win.exe Qvel#*-4  
try{ kD7'BP/#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); QpRk5NeLe  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *ae)<l3v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5.DmMG[T^=  
fileFetch.start(); G9GHBwT  
} W\mgM2p  
catch(Exception e){e.printStackTrace ();} -]{ _^
 
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} 7G*rxn"d  
qk>SM|{  
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public static void main(String[] args) i_QiE2d  
{ w'XSkI_ay  
new TestMethod(); eVB43]g  
} \I^"^'CP  
} 5rc3jIXc{|  
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