http断点续传简单实现（java)

/* 8UANB]@Y}  
**SiteFileFetch.java @}^eyS$|!  
*/ p7YfOUo k  
package NetFox; 51\N+  
import java.io.*; %N, P? ,U  
import java.net.*; 7z?rx  
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public class SiteFileFetch extends Thread { M-B-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ).Ei:/*j  
long[] nStartPos; //开始位置 .LX8ko  
long[] nEndPos; //结束位置 yM8<)6=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p^s k?E  
long nFileLength; //文件长度 )L%i"=<Bdy  
boolean bFirst = true; //是否第一次取文件 &>Ko}?w  
boolean bStop = false; //停止标志 J6)&b7  
File tmpFile; //文件下载的临时信息 =:!$'q:  
DataOutputStream output; //输出到文件的输出流 !/},k"p6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zz4.gkU  
public SiteFileFetch(SiteInfoBean bean) throws IOException mN9Uyz5G  
{ 7JedS  
siteInfoBean = bean; m#(tBfH[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WG_20JdJY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %Ny`d49&  
if(tmpFile.exists ()) #xopJaY  
{ ?B&@  
bFirst = false; MZ8jL,a^  
read_nPos(); S4jt*]w5b  
} l^F%fIRp)  
else ^rDT+ x  
{ rX*ATN  
nStartPos = new long[bean.getNSplitter()]; M99gDN  
nEndPos = new long[bean.getNSplitter()]; PKx ewd  
} SseMTw:  
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} LE|*Je3a  
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public void run()
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{ O@ GEl  
//获得文件长度 8%$V
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//分割文件 WB=pRC@  
//实例FileSplitterFetch Cyb-}l  
//启动FileSplitterFetch线程 H8ws6}C  
//等待子线程返回 vlD!YNy  
try{ 9 pGND]tIi  
if(bFirst) 2ja@NT  
{ M=!RJ%6f  
nFileLength = getFileSize(); u7e g:0Y  
if(nFileLength == -1) e*Gm()Vu,  
{ e$E~@{[1)  
System.err.println("File Length is not known!"); (X rrnoz  
} ~9:ILCfX  
else if(nFileLength == -2) ,u^S(vxyz  
{ k+"+s bsW'  
System.err.println("File is not access!"); ',MiD=_  
}
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else vFK&63  
{ 7H-,:8  
for(int i=0;i<nStartPos.length;i++) o|s JTY  
{ <&?gpRK  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y}bJN%M  
} `>1"v9eF
 
for(int i=0;i<nEndPos.length-1;i++) idC4yH42  
{ 2 NgEzY5  
nEndPos = nStartPos[i+1]; LWB"}#vt  
} G36}4  
nEndPos[nEndPos.length-1] = nFileLength; U#O6l-xe]  
} (;V=A4F-D  
} *ay>MlcV2=  
?,JN?  
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//启动子线程 iI[Z|"a21  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >@yHa'*9S  
for(int i=0;i<nStartPos.length;i++) 3&D;V;ON}_  
{ &=sVq^d@qe  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R;P>_ei(LK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <"uT=]wZ=  
nStartPos,nEndPos,i); o@`& h} $  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [mSK!Y@u  
fileSplitterFetch.start(); ^KU:5Bn  
} i>9/vwe  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CjzfU*G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); oRM,_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3dnL\AqC  
nEndPos = " + nFileLength); g& yR-  
// fileSplitterFetch[nPos.length-1].start(); c3gy{:lb  
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//等待子线程结束 zfE;)K^"  
//int count = 0; aW8Bx\q  
//是否结束while循环 ?-g=Rfpag  
boolean breakWhile = false; OQ$77]XtvL  
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while(!bStop) qAsZ,ik  
{ $X%GzrN  
write_nPos(); }2.^n{Y  
Utility.sleep(500); v hUn3|  
breakWhile = true; &(fB+VNrOH  
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for(int i=0;i<nStartPos.length;i++) b9[KdVsT6^  
{ [_jTy;E  
if(!fileSplitterFetch.bDownOver) TqNEU<S/t  
{ yA%(!v5UT  
breakWhile = false; EO'[AU%~  
break; vgzNT4o  
} U9;C#9E  
} 5|ih>?C/(  
if(breakWhile) (Al.hEs'  
break; L&qzX)  
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//count++; }Po&6^  
//if(count>4) Yn,dM~|Cc
 
// siteStop(); R/ 7G  
} "t+VF4r  
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System.err.println("文件下载结束！"); E+$vIYq:W  
} x.r~e)x=  
catch(Exception e){e.printStackTrace ();} t;9f7~  
} [R j=k)aBm  
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//获得文件长度 jxL5L[  
public long getFileSize() byM/LE7)  
{
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int nFileLength = -1; s> JmLtT  
try{ VdR5ZP  
URL url = new URL(siteInfoBean.getSSiteURL()); CTt3W>'=+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 06I'#:]  
httpConnection.setRequestProperty("User-Agent","NetFox"); $|!VP'VI  
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int responseCode=httpConnection.getResponseCode(); #.0^;M5Nh  
if(responseCode>=400) M'D;2qo  
{ c"%XE#D  
processErrorCode(responseCode); 2.Ym  
return -2; //-2 represent access is error hq/k}Y  
} 6hSj)  
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String sHeader; 2RKI M(~  
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for(int i=1;;i++) $=n|MbFl  
{ /Cr0jWu _  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j_
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//Utility.log(in.readLine()); h2+vl@X  
sHeader=httpConnection.getHeaderFieldKey(i); q>w@W:tZ  
if(sHeader!=null) #rzq9}9tB  
{ wH[@#UP3l  
if(sHeader.equals("Content-Length")) :{C#<g`  
{ GVZ/`^ndM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |_aE~_  
break; KYVB=14  
} DY?`Y%"  
}
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else I ms?^`N  
break; gh
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} o"t+G/M  
} -MoI{3a  
catch(IOException e){e.printStackTrace ();} RX:\@c&  
catch(Exception e){e.printStackTrace ();}  m2%uGqz  
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Utility.log(nFileLength); *G$tfb(  
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return nFileLength; k( 1rp|qf  
} ="3Hc=1?R  
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//保存下载信息（文件指针位置） {) 4
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private void write_nPos() :{%6<j  
{ O'U0Y8HN  
try{ MuYr?1<q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #"%oz^~\  
output.writeInt(nStartPos.length); `N}<lg(0#  
for(int i=0;i<nStartPos.length;i++) e{Pgz0sOQ  
{ L.lmbxn  
// output.writeLong(nPos); R3wK@D  
output.writeLong(fileSplitterFetch.nStartPos); X!,P] G  
output.writeLong(fileSplitterFetch.nEndPos); 0U ?1Yh7 m  
} mkT
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output.close(); |4
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} Fs<kMT  
catch(IOException e){e.printStackTrace ();} -DhF> 4f  
catch(Exception e){e.printStackTrace ();} '
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} J@(=#z8xS  
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c[?S}u|['  
//读取保存的下载信息（文件指针位置） nK1XJp  
private void read_nPos() l%.3hId-  
{ }m/aigA[1  
try{ 9*RfOdnNe  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =(K;z9OR  
int nCount = input.readInt(); L{Epkay,{  
nStartPos = new long[nCount]; tTe\#
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nEndPos = new long[nCount]; &CF74AN#  
for(int i=0;i<nStartPos.length;i++) cysYjuI i  
{ F4>}mIA  
nStartPos = input.readLong(); ItHKpTer  
nEndPos = input.readLong(); wx BQ#OE  
} ^o,Hu
#  
input.close(); eI; %/6#  
} gvYa&N  
catch(IOException e){e.printStackTrace ();} $ w:QJ~,s  
catch(Exception e){e.printStackTrace ();} #z-6mRB  
} Fe%Q8RIh_  
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private void processErrorCode(int nErrorCode) 3\|e
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{ oHB51< }  
System.err.println("Error Code : " + nErrorCode); `;*%5WD%  
} yPn5l/pDDr  
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//停止文件下载 -4Zf0r1u  
public void siteStop() :,y V?E6]  
{ d%VGfSrKq  
bStop = true; W@AZ
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for(int i=0;i<nStartPos.length;i++) 6GMQgTY^  
fileSplitterFetch.splitterStop(); CspY+%3$  
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} oat*
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} 'g^;_=^G  
//负责部分文件的抓取 9 Bz~3  
**FileSplitterFetch.java BQ,]]}e43z  
*/ p82&X+v/p  
package NetFox; 8#2PJHl;  
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thOQcOf0$  
import java.io.*; %A`f>v.7 c  
import java.net.*; f8L  
[{ K$sd  
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public class FileSplitterFetch extends Thread { ?Q="w5OOD  
8<Asg2]6  
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String sURL; //File URL Hwklk9U
 
long nStartPos; //File Snippet Start Position [IF3,C  
long nEndPos; //File Snippet End Position '{QbjG%<P  
int nThreadID; //Thread's ID <tMiI)0%  
boolean bDownOver = false; //Downing is over sKB])mf]  
boolean bStop = false; //Stop identical |L.QIr,jCC  
FileAccessI fileAccessI = null; //File Access interface `Q<hL{AH  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException bT,]=h"0  
{ U PGS  
this.sURL = sURL; acdaDY  
this.nStartPos = nStart; M'$n".,p  
this.nEndPos = nEnd; lE`hC#m  
nThreadID = id; R"];`F(#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 gsGwf[XdJ  
}
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public void run() 29z+<?K{  
{ epJVs0W  
while(nStartPos < nEndPos && !bStop) K;,n?Q w  
{ +IK~a9t  
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try{ A/lxXy}D  
URL url = new URL(sURL); [53rSr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4M*UVdJ;  
httpConnection.setRequestProperty("User-Agent","NetFox"); b|u4h9  
String sProperty = "bytes="+nStartPos+"-"; I{;s.2  
httpConnection.setRequestProperty("RANGE",sProperty); q62TYg}  
Utility.log(sProperty); 79n,bb5  
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InputStream input = httpConnection.getInputStream(); 36@)a
5  
//logResponseHead(httpConnection); `S2YBKz,1  
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byte[] b = new byte[1024]; |+mhYq|`  
int nRead; vo-n9Bj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '=G4R{  
{ )3=
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nStartPos += fileAccessI.write(b,0,nRead); xqmP/1=NO
 
//if(nThreadID == 1) Xnt`7L<L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zq80}5%2CT  
} RvZi%)  
K%[Rv#>;q|  
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Utility.log("Thread " + nThreadID + " is over!"); :[#HP66[O5  
bDownOver = true; r4@!QR<h  
//nPos = fileAccessI.write (b,0,nRead); f7)}A/$4+  
} "S(m1L?  
catch(Exception e){e.printStackTrace ();} &"BmCDOq  
} ?=dyU(  
} &Y\Vh}  
k`
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;gcQ9L  
//打印回应的头信息 ib/B!?/
 
public void logResponseHead(HttpURLConnection con) ~QJD.'z  
{ !sfO
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for(int i=1;;i++) 8E H#IiP  
{ s
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String header=con.getHeaderFieldKey(i); u3R0_8 _.w  
if(header!=null) "pa5+N&2-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +M$2:[xRT  
Utility.log(header+" : "+con.getHeaderField(header)); F[ N{7C3  
else sI,T"D?  
break; W
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} _&FcHwRy  
} C8}ujC  
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public void splitterStop() Q1mz~r  
{ d!
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bStop = true; &[`p qX  
} |eAl!k  
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} 68V66:0  
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/* K||9m+  
**FileAccess.java ^&am]W;T  
*//文件访问(定位，写) R9f*&lj  
package NetFox; - U!:.  
import java.io.*; K%P$#a  
iK#5HW{  
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public class FileAccessI implements Serializable{ _Ft4F`pM  
 Aa[p7{e  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |Kky+*  
RandomAccessFile oSavedFile; UBs'3M  
long nPos; m]R< :_  
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public FileAccessI() throws IOException P6&@fwJ<  
{ PCF!Y(l  
this("",0); B4
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} 8fKt6T  
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public FileAccessI(String sName,long nPos) throws IOException Z)<ljW  
{ _Isju S  
oSavedFile = new RandomAccessFile(sName,"rw"); SL zL/5s  
this.nPos = nPos; {"S"V  
oSavedFile.seek(nPos); &Ey5 H?U!  
} -'QvUHL|  
kzny4v[y  
?wt%e;  
public synchronized int write(byte[] b,int nStart,int nLen) @(Wx(3JR?}  
{ @G+Hrd6  
int n = -1; <f%JZ4p*  
try{ -"YQo  
oSavedFile.write(b,nStart,nLen); |'9%vtbM  
n = nLen; "toyfZq@  
} }dX[u`zQ  
catch(IOException e) ~McmlJzJG  
{ 7dyGC:YuTL  
e.printStackTrace (); -D?T0>  
} xQ\/6|  
kE;h[No&K  
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return n; |6'(yn  
} ?lW-NPr  
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} GGo)k1T|)  
/)sA{q 4  

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/* ~B;kFdcVXn  
**SiteInfoBean.java 3[B*l@}j  
*/
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package NetFox; FivgOa  
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-CtLL_I  
public class SiteInfoBean { ,l^; ZE  
}R4%%)j(Vj  
p \A^kX^5  
private String sSiteURL; //Site's URL o%XAw   
private String sFilePath; //Saved File's Path kW0|\
 
private String sFileName; //Saved File's Name DP ,owk  
private int nSplitter; //Count of Splited Downloading File c ]M!4.  
~XQj0'  
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public SiteInfoBean() va F^[/ (g  
{//nSplitter的缺省值为5 =Ryh@X&  
//default value of nSplitter is 5 M]4qS('[  
this("","","",5); ,r
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} !`"@!  
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9X  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Fka&\9i  
{ /tR@J8pV  
sSiteURL= sURL; "| cNY_$&s  
sFilePath = sPath; Sm(X/P=z  
sFileName = sName; )'3(=F$+l  
this.nSplitter = nSpiltter; ATl.Qku@  
9Jd{HI
=  
> 2_xRn<P  
} #=C!Xx&  
^kJ(bBY  
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public String getSSiteURL() z+,l"#Vv  
{ C1&~Y.6m  
return sSiteURL; p vone,y2  
} n6D9f~8"  
1><@$kVMm~  
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public void setSSiteURL(String value) 3Kuu9<0  
{ &x6Z=|Ers  
sSiteURL = value; E0; }e  
} Br^4N9  
tS#=I.ET  
&XAG| #  
public String getSFilePath() hG51jVYtw  
{ Lc4\i  
return sFilePath; ?#~3%$>  
} lZ]x #v  
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~,[-
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public void setSFilePath(String value) [Q+8Ku  
{ 2..b/  
sFilePath = value; u
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} 4)MKYhm  
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XgRrJ.  
public String getSFileName() Wmri%  
{ >%Rb}Ki4  
return sFileName; EGpN@  
} >K:| +XbH  
/g$cQ=c  
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public void setSFileName(String value) tg =ClZ-  
{ Y'K+O  
sFileName = value; t8SvU  
} ]^aOYtKX  
/zxLnT; 5  
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public int getNSplitter() X*f#S:kiNU  
{ ueI1O/Mi  
return nSplitter; Su"9`  
} T%0vifoQ_$  
1,UeVw/  
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public void setNSplitter(int nCount) p5F
=?*[}  
{ eh4`a
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nSplitter = nCount; \"r84@<  
} 9vIqGz-o  
} Pnf|9?~$H  
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+c4-7/kE  
/* q8&2
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**Utility.java j"G1D-S:  
*/ 2cv!85  
package NetFox; g-G;8x'n  

\
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public class Utility { kpF")0qr  
%LI[+#QE  
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public Utility() 3B*b d  
{ 4)-
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} ,q9nHZG^  
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//线程睡眠 u7PtGN0r%  
public static void sleep(int nSecond) kH;DAphk  
{ =[A5qwyv  
try{ ai,\'%N  
Thread.sleep(nSecond); &8=wkG%  
} JSXJlau  
catch(Exception e) %@C(H%obWd  
{ V2Iqk]V%y  
e.printStackTrace (); FKYPkFB  
} +Cs[
]~  
} u.\FNa  
;4(ULJ*  
//日志 *[VO03  
public static void log(String sMsg) eXs^YPi  
{ _:N+mEF  
System.err.println(sMsg); ub/Z'!  
} `.oWmBey\  
L@mNfLK  
h=?V)WSM  
public static void log(int sMsg) a7$]" T 7  
{ pFB^l|\ ]  
System.err.println(sMsg); fEv`iXZG  
} 31VDlcnE  
} " a&|{bv  
]81t~t9LQ  
4lM)
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/* .qd/ft2  
**TestMethod.java seQSDCsvw*  
*/ \,n|V3#G  
package NetFox; T[?wbYfW  
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;`")3~M3*  
public class TestMethod { u& 4i=K'x8  
&*Sgyk o`  
;+-@AYl  
public TestMethod() Fx@ovI- 5  
{ ///xx/weblogic60b2_win.exe g?7I7W~?`  
try{ kjj4%0"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); d#tqa`@~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7dm:L'0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); QD8.C=2R  
fileFetch.start(); -RLY.@'d-M  
} %w$\v"^_Y  
catch(Exception e){e.printStackTrace ();} D,3Kx ^  
s0zN#'o]  
{th=MldJ?  
} pA%}CmrMq  
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a-\M)}T  
public static void main(String[] args) 6%-RKQi  
{ L'Yg$9Vz  
new TestMethod(); |]M|IX8 o  
} )7aUDsu>4  
} *\-$.w)k  
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