http断点续传简单实现（java)

/* @l@erCw@  
**SiteFileFetch.java =.6JvX<d1*  
*/ _iZ9Ch\  
package NetFox; %8! }" Xa  
import java.io.*; ~d&W;mef-  
import java.net.*; ]t.6bb4  
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public class SiteFileFetch extends Thread { u*<knZ~ty  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )\l(h%s[I  
long[] nStartPos; //开始位置 -i"?2gK  
long[] nEndPos; //结束位置 f _*F
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 rL<a^/b/=  
long nFileLength; //文件长度 bjB4  
boolean bFirst = true; //是否第一次取文件 6e:#x:O  
boolean bStop = false; //停止标志 76R
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File tmpFile; //文件下载的临时信息 94GF8P  
DataOutputStream output; //输出到文件的输出流 LVxR*O  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） fV5MI[t  
public SiteFileFetch(SiteInfoBean bean) throws IOException C?7I(b:  
{ ^Z:qlYZ  
siteInfoBean = bean; *waaM]u  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lb<D,&+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 61&A`  
if(tmpFile.exists ()) 4Y4QR[>IU3  
{ n_MY69W  
bFirst = false; _Rm1-,3  
read_nPos(); GGkU$qp2~  
} M}xyW"yp  
else C *U,$8j|}  
{
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nStartPos = new long[bean.getNSplitter()]; q#t&\M
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nEndPos = new long[bean.getNSplitter()]; S3.76&  
} geSH3I   
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} F4 :#okt  
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public void run() PNh
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{ [vyi_0[  
//获得文件长度 >}6V=r3[+  
//分割文件 5 p! rZ  
//实例FileSplitterFetch \ 3HB  
//启动FileSplitterFetch线程 _!Ir|j.A  
//等待子线程返回 ;A;FR3=)  
try{ $ {5|{`  
if(bFirst) !ui:0_  
{ IO}5
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nFileLength = getFileSize(); ><3!J+<?  
if(nFileLength == -1) D:vX/mf;7  
{ ~mK|~x01@  
System.err.println("File Length is not known!"); aXRf6:\%  
} $I:&5o i  
else if(nFileLength == -2) ~Rk~Zn  
{ yZw5?{g@  
System.err.println("File is not access!"); ?'+kZ|  
} t p<wMrq<  
else  mPS27z(  
{ \O(~:KN  
for(int i=0;i<nStartPos.length;i++) .<kbYo:MV  
{ PQA}_o  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6PdLJ#LS  
} 6Dz N.fz  
for(int i=0;i<nEndPos.length-1;i++) )HJ#|JpxC  
{ :*dfP
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nEndPos = nStartPos[i+1]; &_W~d0  
} n|AV7c  
nEndPos[nEndPos.length-1] = nFileLength; p^THoF'~T  
} ,)%$Zxng  
} vG'I|OWg  
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 "DsL$D2e  
//启动子线程 8q_"aa,`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /7jb&f   
for(int i=0;i<nStartPos.length;i++) m%)Cw)t 7  
{ wC`+^>WFo  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %+0V0.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nX|]JW  
nStartPos,nEndPos,i); 9A!B|s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =dDr:Y<@*  
fileSplitterFetch.start(); r0(*]K:.  
} 
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), EaU
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |cIv&\ x  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8c^Hfjr0  
nEndPos = " + nFileLength); ^<wn  
// fileSplitterFetch[nPos.length-1].start(); $BUm,  
G
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//等待子线程结束 32x[6"T  
//int count = 0; hG8<@  
//是否结束while循环 83g$k 9lG.  
boolean breakWhile = false; s5 ($b  

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while(!bStop) \k>1q/T0V  
{ AtYqD<hl:  
write_nPos(); .-4]FGg3  
Utility.sleep(500); SBh"^q  
breakWhile = true; U2vM|7]VP  
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for(int i=0;i<nStartPos.length;i++) DuI>z?bS  
{  /wT<p  
if(!fileSplitterFetch.bDownOver) J1g+
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{ U\GuCw  
breakWhile = false; ,4H/>yPw  
break; H?cJ'Q,5  
} iph
}!
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} ?'RB
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if(breakWhile) t+Au6/Dx?  
break; |*n B2  
_:7:ixN[Ie  
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//count++; ae0t*;~  
//if(count>4) (d>}Fp  
// siteStop(); DVz_;m6)  
} ODNZLCB~t  
gAr=fq-|  
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System.err.println("文件下载结束！"); Q:U>nm>xA  
} hI 1or4V  
catch(Exception e){e.printStackTrace ();} Yaj}_M-  
} =:BTv[lv  
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//获得文件长度 U
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public long getFileSize() \-8S"  
{ _o7t| pl~  
int nFileLength = -1; zEk/15  
try{ SW)jDy  
URL url = new URL(siteInfoBean.getSSiteURL()); A~({vb'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zvK'j"Wq=  
httpConnection.setRequestProperty("User-Agent","NetFox"); D`R~d;U~  
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/ }Pj^^6A<  
int responseCode=httpConnection.getResponseCode(); z)Lw\H^/  
if(responseCode>=400) l
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{ ~'v9/I-"  
processErrorCode(responseCode); 7j8lhrM}^  
return -2; //-2 represent access is error *-(8Z>9  
} 6{!Cx9V  
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String sHeader; 4 (XV)QR  
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for(int i=1;;i++) (0E<Fz V  
{ Jq?Fi'2F%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A DVUx}  
//Utility.log(in.readLine());  ZvwU  
sHeader=httpConnection.getHeaderFieldKey(i); Mj`g84  
if(sHeader!=null) 3,?LpdTS  
{ "x3x$JQZy  
if(sHeader.equals("Content-Length")) D)tL}X$  
{ 0.)q5B`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )H(i)$I  
break; XAZPbvG|$  
} /j-c29nz  
} HD'adj_,  
else {2k]$
|  
break; //'&a-%$^  
} +xd@un[r<  
} RM;U
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catch(IOException e){e.printStackTrace ();} =0az5td  
catch(Exception e){e.printStackTrace ();} _L+j6N.h1  
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Utility.log(nFileLength); \FIM'EKzu!  
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return nFileLength;  S~bhh&  
} C\4d.~C:w3  
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//保存下载信息（文件指针位置） #\ uB!;Q  
private void write_nPos() 4n"6<cO5q  
{ 6-z(34&N  
try{  aWPf3Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); bgxk:$E
 
output.writeInt(nStartPos.length); 6j!idA!'  
for(int i=0;i<nStartPos.length;i++) udXzsY9Ng  
{ D?=4'"@v  
// output.writeLong(nPos); =R
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output.writeLong(fileSplitterFetch.nStartPos); }2Tq[rl~s  
output.writeLong(fileSplitterFetch.nEndPos); Fv*Et-8tN5  
} e_"m\e#N  
output.close(); D5!#c-Y-  
} f `D(V-4  
catch(IOException e){e.printStackTrace ();} 70'gVCb  
catch(Exception e){e.printStackTrace ();} -y>~ :.  
} 2Z5_@Y  
)|_L?q#w!'  
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//读取保存的下载信息（文件指针位置） {1qr6P,"  
private void read_nPos() 1[J|AkN  
{ JfY(};&  
try{  S'\e"w  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Npi)R)  
int nCount = input.readInt(); F]t=5 -O<  
nStartPos = new long[nCount]; KaX*) P  
nEndPos = new long[nCount]; Paeq  
for(int i=0;i<nStartPos.length;i++) g)R2V  
{ N6v?Qzvi  
nStartPos = input.readLong(); P*H0Hwn;  
nEndPos = input.readLong(); 1$+8wDVwad  
} @+l=R|  
input.close(); }LeS3\+UHl  
} ,`02fMOLc  
catch(IOException e){e.printStackTrace ();} TMo DN%{  
catch(Exception e){e.printStackTrace ();} T@*'}*  
} yM7Iq)o6u  

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private void processErrorCode(int nErrorCode) N:+)6a  
{ I)yF!E &  
System.err.println("Error Code : " + nErrorCode); k~gOL#$  
} XK\3"`kd  
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//停止文件下载 YYT#{>&  
public void siteStop() x Nj
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{ [uK{``"  
bStop = true; }Z{FPW.QK  
for(int i=0;i<nStartPos.length;i++) #4lIn
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fileSplitterFetch.splitterStop(); ]Vmo>  
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} CJER&"em7  
} k}p8"'O  
//负责部分文件的抓取 $d
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**FileSplitterFetch.java -jy0Kl/p  
*/ \=7jp|{Yl  
package NetFox; i/skU9  
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import java.io.*; gnjhy1o  
import java.net.*; 7F6B  
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public class FileSplitterFetch extends Thread {
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String sURL; //File URL f*B
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long nStartPos; //File Snippet Start Position yi*EobP  
long nEndPos; //File Snippet End Position ~D>pu%F  
int nThreadID; //Thread's ID KX]!yA  
boolean bDownOver = false; //Downing is over 3F@P$4!#l  
boolean bStop = false; //Stop identical Eh ";irE  
FileAccessI fileAccessI = null; //File Access interface $xbW*w  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v&'#Gg  
{ q[C?1Kc.z  
this.sURL = sURL; 9O:l0 l  
this.nStartPos = nStart; x(vQ%JC  
this.nEndPos = nEnd; g27'il  
nThreadID = id; 9aY8`B  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V^&*y+  
} 5.oIyC^Ik  
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*=2W:,$  
public void run() ~bxev/$d  
{ 4|E^ #C  
while(nStartPos < nEndPos && !bStop) giX[2`^NG  
{ xsn=Ji2 F  
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/  
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try{ {\(MMTQ  
URL url = new URL(sURL); gWGDm~+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $q)YC.5$  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4minzrKM\  
String sProperty = "bytes="+nStartPos+"-"; z&t
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httpConnection.setRequestProperty("RANGE",sProperty); @
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Utility.log(sProperty); sHc-xnd  
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InputStream input = httpConnection.getInputStream(); )\=
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//logResponseHead(httpConnection); w+R7NFq  
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byte[] b = new byte[1024]; (pd$?vRy  
int nRead; &<]f-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [i/!o
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{ H{vKk  
nStartPos += fileAccessI.write(b,0,nRead); lQHF=Jex  
//if(nThreadID == 1) X<}}DZSu a  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ly+UY.v"  
} ^ls@Gr7`P  
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Utility.log("Thread " + nThreadID + " is over!"); +h4W<YnW  
bDownOver = true; c\1
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//nPos = fileAccessI.write (b,0,nRead); @%R4V[Lo.  
} n jWe^  
catch(Exception e){e.printStackTrace ();} 3X`9&0:j%  
} ?gl&q+mv  
} G/<zd)  
#BUq;5  
"mW'tm1+  
//打印回应的头信息 oNAnJ+_  
public void logResponseHead(HttpURLConnection con) igfQ,LWe!  
{ |(z{)yWbC[  
for(int i=1;;i++) b4
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{ oCaYmi=:  
String header=con.getHeaderFieldKey(i); &sWr)>vs  
if(header!=null) p8~lGuH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !%,7*F(  
Utility.log(header+" : "+con.getHeaderField(header)); {,Q)D$i  
else P3&s<mh  
break; ORs:S$Nt$  
} A_zCSRF,  
} BB/wL_=:  
i D IY|  
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public void splitterStop() KFd +7C9  
{ 7Ed0BJTa  
bStop = true; |l; Ot=C=  
} WzN c=@[W  
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} {fR\yWkt?  
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/* h9H z6 >  
**FileAccess.java 4d@yAr}  
*//文件访问(定位，写) 5qtk#FB  
package NetFox; j%Au0k
 
import java.io.*; .[O{,
r  
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public class FileAccessI implements Serializable{ L/tpT?$fi  
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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 4H-eFs%5  
RandomAccessFile oSavedFile; yxt"vm;  
long nPos; :W*yfhLt  
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public FileAccessI() throws IOException s|Mo3_>  
{ |u>(~6  
this("",0); x.+T65X~4  
} h+Co:pr  
*/;7Uv7  
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public FileAccessI(String sName,long nPos) throws IOException IgX &aW
 
{ 6!m#;8 4  
oSavedFile = new RandomAccessFile(sName,"rw"); jq,M1  
this.nPos = nPos; m^3x%
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oSavedFile.seek(nPos); Te+(7 Z  
} *4U_MM#rX  
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'  
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public synchronized int write(byte[] b,int nStart,int nLen) = j1Jl^[  
{ >a?Bk4w  
int n = -1; v1OVrk>s>  
try{ fvC,P#z'|  
oSavedFile.write(b,nStart,nLen); Ss>pNH@c  
n = nLen; |U|>YA1[b  
} J\@6YU[A  
catch(IOException e) d+q],\"R  
{ duY?LJ@g  
e.printStackTrace (); i/9iM\2  
} kW/G=_6  
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return n; 6'Q{xJe?  
} <L-F3Buu  
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} u<edO+  
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/* g<j)   
**SiteInfoBean.java Z =+Z96  
*/ xe!bfzU  
package NetFox; 8fXiadP#  
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public class SiteInfoBean { YRu@;
`  
kB 8^v7o  
9
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private String sSiteURL; //Site's URL ?\V#^q-  
private String sFilePath; //Saved File's Path B6 0  
private String sFileName; //Saved File's Name e(0OZ_w  
private int nSplitter; //Count of Splited Downloading File Ehx9-*]
 
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public SiteInfoBean() `8!9Fp  
{//nSplitter的缺省值为5 h=#w< @  
//default value of nSplitter is 5 `B)@  
this("","","",5); _,J+b R+b  
} w2DC5ei'  
b#_RZ  
2ioHhcYdJU  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~>CvZ7K  
{ G}nJ3  
sSiteURL= sURL; 7:jLZ!mgi  
sFilePath = sPath; {kpF etXt?  
sFileName = sName; z?o8h N\  
this.nSplitter = nSpiltter; X8)k'h  
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=)Xj[NNRT
 
} g:Hj1!'  
~:DL{ZeEb  
?:"ABkL|+Y  
public String getSSiteURL() 6 VEB2F  
{ cC/h7odY  
return sSiteURL; jWrU'X  
} X)b$CG  
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4aXIRu%#7  
public void setSSiteURL(String value) 1/}H 0\9'  
{ =-U0r$sK+F  
sSiteURL = value; sO.MUj;  
} gm9*z.S\'  
0kE[=#'.'  
i7Qb~RW  
public String getSFilePath() KQ\K:#  
{ .#( vx;  
return sFilePath; Q-<]'E#\(  
} 6 5govor  
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public void setSFilePath(String value) _uIS[%4g  
{ FZi@h  
sFilePath = value; Sm'Tz&!  
} h(
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Z [!"x&H]h  
-#Zdf|  
public String getSFileName() 2K}49*  
{ w!f2~j~  
return sFileName; &;@L] o  
} "jL>P)  

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cH5i420;aO  
public void setSFileName(String value) f[o~d`
z  
{ ',EI[ ]+  
sFileName = value; N~)-\T:ap  
} `zQuhD 8W  
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public int getNSplitter() "Rj PTRe:  
{ s=8H<'l  
return nSplitter; v) n-  
} f.6>6%l  
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iWCYK7c@.-  
public void setNSplitter(int nCount) )?rq8VO  
{
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nSplitter = nCount; ` Ig5*X4|  
} FV^jCseZ  
} 6`e{l+c=
F  
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~,)jZ-fw  
/* 6W i n!4  
**Utility.java d/d)MoaJ*t  
*/ iH(7.?.r  
package NetFox; {++EX2  
a/J<(sak~X  
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public class Utility { 2-4N)q  
rq%]CsRY5  
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public Utility() |*bUcS<S  
{ tq L(H25z  
"to!&@I| 4  
{nmG/dn{  
} # -'A =j  
MLDzWZ~}ef  
//线程睡眠 =KPmZ,/w  
public static void sleep(int nSecond) w"R<8e=  
{ %-n)L  
try{ Xh"9Bcjf  
Thread.sleep(nSecond); o#qdgZ  
} ](r}`u%}y  
catch(Exception e) Hx#YN*\.M  
{ ?}HK!feU  
e.printStackTrace (); j yHa}OT  
} b31$i 5{  
} w.m8SvS&b  
BE?]P?r?  
//日志 pCKP{c=6Q  
public static void log(String sMsg)
-E7mt`:d  
{ _pdKcE\X  
System.err.println(sMsg); I\)`,w  
} KXt8IMP_"y  
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public static void log(int sMsg) P+CV4;Xz  
{ rNN>tpZ}  
System.err.println(sMsg); 8Ths"zwn  
} 5:@b
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} \[G'cE  
ifn=De3+  
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/* PD&e6;rj;  
**TestMethod.java HoQb.Z  
*/ }c,b]!:  
package NetFox; TEV DES  
#0AyC.\  
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public class TestMethod { 0,hs%x>v  
U%vTmdOY  
<'=!f6Wh  
public TestMethod() 971=OEyq*  
{ ///xx/weblogic60b2_win.exe \,;glY=M!  
try{ NO5k1/-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); W2{w<<\$3}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `EKf1U\FI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +`>7cy%cZ  
fileFetch.start(); >.wZEQ6QK  
} 3Zp<#  
catch(Exception e){e.printStackTrace ();} <#0i*PM_  
+^7cS6"L  
!oz{XWE  
} UBd+,]"f  
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w:zo \  
public static void main(String[] args) <K)]kf  
{ zjoo;(?D|  
new TestMethod(); J6#h~fpv  
} .X!!dx1<  
} S_7]_GQ9  
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