http断点续传简单实现（java)

/* d~S.PRg=  
**SiteFileFetch.java 8_Y{7;<ey  
*/ {TzKHnP  
package NetFox; ]J;^< 4l  
import java.io.*; ]![ewO@  
import java.net.*; @a>+r1  
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public class SiteFileFetch extends Thread { 9:fVHynr  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Si6%6rAhj  
long[] nStartPos; //开始位置 /_x?PiL  
long[] nEndPos; //结束位置 +%?_1bGX>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Bu>srX9f  
long nFileLength; //文件长度 )f(#Fn  
boolean bFirst = true; //是否第一次取文件 ;'}1  
boolean bStop = false; //停止标志 4rwfY<G  
File tmpFile; //文件下载的临时信息 @ L%3}  
DataOutputStream output; //输出到文件的输出流 I@+dE V`Lf  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &UbNp8h  
public SiteFileFetch(SiteInfoBean bean) throws IOException exTpy  
{ eO(VSjo'`  
siteInfoBean = bean; @5acTYQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9!_`HE+(XJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z\(+a
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if(tmpFile.exists ()) D gY2:&0  
{ ~6
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bFirst = false; R7Zx
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read_nPos(); !(uyqplTk  
} ,Ztj  
else ["MF-tQ5  
{ {{SQL)yJ  
nStartPos = new long[bean.getNSplitter()]; G0CmY43  
nEndPos = new long[bean.getNSplitter()]; ,U]
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} PM7*@~.  
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} `cy_@Z5A  
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public void run() $khWu>b  
{ 2o6KVQ  
//获得文件长度 $w)y
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//分割文件 tP"C>#LO  
//实例FileSplitterFetch Q;)[~p  
//启动FileSplitterFetch线程 ,K+K`"Oy  
//等待子线程返回 (/v(.t  
try{ 9{'GrL  
if(bFirst) Jq<&`6hn  
{ 8"N<g'Yl,  
nFileLength = getFileSize(); F.c,FR2  
if(nFileLength == -1) #J)sz,)(  
{ \a<qI  
System.err.println("File Length is not known!"); >y(;k|
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} zp!{u{  
else if(nFileLength == -2) v'`C16&^]  
{ ou
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System.err.println("File is not access!"); @4sv(HyDY  
} l<(
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else 3RXq/E  
{ oa}-=hG  
for(int i=0;i<nStartPos.length;i++) g9<*+fV 2$  
{ U$# ?Lw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); TlQ#0_as[  
} +Z/*=;  
for(int i=0;i<nEndPos.length-1;i++) Cc$!TZq=  
{ {tOu+zy  
nEndPos = nStartPos[i+1]; sn@gchO9s  
} r[q-O&2&  
nEndPos[nEndPos.length-1] = nFileLength; Q
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} rt_%_f>qd  
} F7Mf>."  
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c]
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//启动子线程 }XX)U_x  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; CDK0 $W n  
for(int i=0;i<nStartPos.length;i++) ?y>P  
{ vYKKv%LE  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Urm&4&y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +Hc[5WL  
nStartPos,nEndPos,i); ;;2XLkWu  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5qt]~v%y  
fileSplitterFetch.start(); E2Q;1Re@  
} mHM38T9C%
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b" 1a7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r.lH@}i%n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p3&/F=T;)  
nEndPos = " + nFileLength); `J'xVq#O  
// fileSplitterFetch[nPos.length-1].start(); *l)_&p  
?S~HnIn  
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//等待子线程结束 }JeG
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//int count = 0; ]e$mTRi*  
//是否结束while循环 M/EEoK^K@  
boolean breakWhile = false; )iNMjg  
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while(!bStop) =kp#v  
{ F@1~aeX-  
write_nPos(); zq>pK_WG  
Utility.sleep(500); @i'R
IL}  
breakWhile = true; Q})x4  
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for(int i=0;i<nStartPos.length;i++) 1p[C5j3  
{ <4ccTl  
if(!fileSplitterFetch.bDownOver) ` .|JTm[  
{ [a:yKJ[  
breakWhile = false; GbUw:I  
break; 5Ev9u),D+v  
} 'Ybd'|t{}  
} t3|If@T  
if(breakWhile) $sTbFY  
break; ~Z9Eb|B  
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V7U&8UPb  
//count++; eee77.@y-p  
//if(count>4) cY8XA6  
// siteStop(); |`+kZ-M*  
} A'vQtlvKA  
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System.err.println("文件下载结束！"); ##+|zka!U  
} cXU8}>qY7  
catch(Exception e){e.printStackTrace ();} Uy2NZ%rnt  
} "(zvI>A  
)h6hN"#V5  
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//获得文件长度 UCG8=+t5T  
public long getFileSize() e/Wrm^]y  
{ Ydm0  
int nFileLength = -1; jd8`D6|Z  
try{ f4UnLig  
URL url = new URL(siteInfoBean.getSSiteURL()); 7|%|w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZUePHI-dP  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q9
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" !F)K  
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int responseCode=httpConnection.getResponseCode(); 'w3BSaJi  
if(responseCode>=400) $0$'co"  
{ Yv<'QC  
processErrorCode(responseCode); ]L+YnZ?6  
return -2; //-2 represent access is error PP)iw@9j  
} QK%Nt
 
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String sHeader; %IrR+f+H  
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for(int i=1;;i++) 4wYD-MB  
{ <Hd8Jd4f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vU
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//Utility.log(in.readLine()); 'D`O4TsP>  
sHeader=httpConnection.getHeaderFieldKey(i); 'NJGez'b,  
if(sHeader!=null) j5Kw0Wy7  
{ ZByxC*Cz  
if(sHeader.equals("Content-Length")) !"1}zeve  
{ B7PkCS&X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KYE)#<V}@  
break; 1 aWzd[i  
} $J6Pv   
} PD #9Z=Hj  
else Dl=9<:6FW  
break;
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} 8T6LD  
} !dnCrR  
catch(IOException e){e.printStackTrace ();} g)0>J  
catch(Exception e){e.printStackTrace ();} ~o{GQ>  
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Utility.log(nFileLength); V"Cx5#\7C  
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return nFileLength; w>#{Nl7gz  
} ]oT8H?%*Y  
;f;A"  
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//保存下载信息（文件指针位置） m=Mb'<  
private void write_nPos() (V&5EO8)  
{ o>|&k]W/  
try{ e"}JHXs  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ba5,?FVI~  
output.writeInt(nStartPos.length); o\/&05rp]  
for(int i=0;i<nStartPos.length;i++) /{1sU}k-  
{ yyPQ^{zD  
// output.writeLong(nPos); "PgVvm#w'  
output.writeLong(fileSplitterFetch.nStartPos); &10l80vj  
output.writeLong(fileSplitterFetch.nEndPos); M3XG s|gw  
} ?^Gi;d5  
output.close(); ,+w9_Gy2H  
} -e_91WI  
catch(IOException e){e.printStackTrace ();} Vn&{yCm3  
catch(Exception e){e.printStackTrace ();} cp1-eR_&  
} /80H.|8O  
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//读取保存的下载信息（文件指针位置） Ibf~gr(j  
private void read_nPos() 8y:/!rRN  
{ ;x<5F+b  
try{ mJxr"cwHl  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {F!/\2a  
int nCount = input.readInt(); S?b^g'5m  
nStartPos = new long[nCount]; M)x6m|.=  
nEndPos = new long[nCount]; 1`hmD1d  
for(int i=0;i<nStartPos.length;i++) oX=dJJE  
{ v~8CpC  
nStartPos = input.readLong(); _+!@c6k)ra  
nEndPos = input.readLong(); @},|i*H/  
} R*[X. H  
input.close(); H1GmC`\<[:  
} [T |P|\M  
catch(IOException e){e.printStackTrace ();} N5PW]  
catch(Exception e){e.printStackTrace ();} J#.f%V
J  
} Ky0}phGRu  
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private void processErrorCode(int nErrorCode) Vc[aNpE  
{ r'
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System.err.println("Error Code : " + nErrorCode); O]4v\~@-j  
} X<%`  
@V?T'@W7D  
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//停止文件下载 e{EC#%x_  
public void siteStop() kzE<Y  
{ V` T l$EF  
bStop = true; NX[-Y]t  
for(int i=0;i<nStartPos.length;i++) ]OSq}ul  
fileSplitterFetch.splitterStop(); K`=9"v'f+  
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} {MRXKnm;e  
} zRU9Q2Y  
//负责部分文件的抓取 d*YVk{s7V  
**FileSplitterFetch.java T,a71"c  
*/ '[Sm w'n6-  
package NetFox; c@
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import java.io.*; Ucx"\/"  
import java.net.*; z!M #  
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public class FileSplitterFetch extends Thread { ["O_Phb|  
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String sURL; //File URL eMV{rFmT  
long nStartPos; //File Snippet Start Position k vpkWD;  
long nEndPos; //File Snippet End Position e#U@n j6  
int nThreadID; //Thread's ID ;AG&QdTMh  
boolean bDownOver = false; //Downing is over +v2)'?BS  
boolean bStop = false; //Stop identical r|63T%q!  
FileAccessI fileAccessI = null; //File Access interface HA J[Y3d<  
sYq:2Wn>8Q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _1?nLx7n  
{ w%?Zb[!&  
this.sURL = sURL; 5tI#UBha  
this.nStartPos = nStart; zv7)JH7EV&  
this.nEndPos = nEnd; \0W0o5c$  
nThreadID = id; GlHP`&;UH  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mm9uhlV8  
} x?UAj8z6  
{?;qy\m]o  
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public void run() iT;Ld $!{f  
{ +7Uv|LZ~@  
while(nStartPos < nEndPos && !bStop) VFrp7;z43  
{ v8YF+N  
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try{ zcC:b4  
URL url = new URL(sURL); =]r2;014  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); cL<,]%SkE  
String sProperty = "bytes="+nStartPos+"-"; X }`
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httpConnection.setRequestProperty("RANGE",sProperty); xnC:?d  
Utility.log(sProperty); sf0\#Q  
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InputStream input = httpConnection.getInputStream(); V'tqsKQ
!  
//logResponseHead(httpConnection); N%,zME  
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byte[] b = new byte[1024]; A^E 6)A=  
int nRead; 3RX9LJGX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0h~{K  
{ !{
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nStartPos += fileAccessI.write(b,0,nRead); \1
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//if(nThreadID == 1) f
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QE8`nMf  
} L PS,\+  
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Utility.log("Thread " + nThreadID + " is over!"); fP[S.7F+No  
bDownOver = true; F [Lg,}  
//nPos = fileAccessI.write (b,0,nRead); 1 0zw}1x  
} K^6d_b&  
catch(Exception e){e.printStackTrace ();} -%0pYB  
} gAh#H ?MM  
} Q5hOVD%  
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//打印回应的头信息 #K`0b$
  
public void logResponseHead(HttpURLConnection con) NiFe#SLA  
{ aZ|?i }  
for(int i=1;;i++) E]v]fy"  
{ Go!{@xx>  
String header=con.getHeaderFieldKey(i); w=CzPNRHH!  
if(header!=null) q'/o=De  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o%f:BJS  
Utility.log(header+" : "+con.getHeaderField(header)); n|pdYe8\  
else *T#^|<.XG  
break; oY5`r)C7  
} $bD`B'5  
} [mv!r-=  
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public void splitterStop() Z)IF3{*  
{ D)bL;h  
bStop = true; xFekSH7[F  
} (c&%1bJ  
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} ZqdoYU'  
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/* >&Oql9_  
**FileAccess.java u;]xAr1  
*//文件访问(定位，写) `a:3S@n(}  
package NetFox; k$ T  
import java.io.*; ;Xa N  
AAs&P+;  
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public class FileAccessI implements Serializable{ Q-!gO  
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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 9J~\.:jH-  
RandomAccessFile oSavedFile; j:qexhtho  
long nPos; ^%!SKhRIK  
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public FileAccessI() throws IOException WF-jy7+  
{ r{t6Vv2J  
this("",0); L&y"oAp<  
} &PH:J*?C}  
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public FileAccessI(String sName,long nPos) throws IOException 4;W{#jk  
{ M|
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oSavedFile = new RandomAccessFile(sName,"rw"); k0O5c[j  
this.nPos = nPos; %LzARTX
 
oSavedFile.seek(nPos); w~'}uh  
} S6_:\Q  
a$h^<D ^  
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public synchronized int write(byte[] b,int nStart,int nLen) WR`NISSp  
{ J^ewG  
int n = -1; 7H?xp_D  
try{ 4Ngp  -  
oSavedFile.write(b,nStart,nLen); j}B86oX  
n = nLen; yci}#,nb  
} +}M3O]?4  
catch(IOException e) kxd
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{ \v6lcA
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e.printStackTrace (); Z\Ur F0  
}  T&MhSJf#  
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return n; Y)]C.V,~  
} rX /'  
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*!JB^5(H  
} L@/IyQ[H1  
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Z)$@1Q4P?1  
/* "g#%d  
**SiteInfoBean.java ^r.CUhx)  
*/ L'S,=NYXY  
package NetFox; )qw;KG0F  
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public class SiteInfoBean { !`RMXUV  
O
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private String sSiteURL; //Site's URL nDXEm6|e  
private String sFilePath; //Saved File's Path qbeUc5`1  
private String sFileName; //Saved File's Name W+6
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private int nSplitter; //Count of Splited Downloading File [:#K_EI5%  
knYp"<qj  
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public SiteInfoBean() S4 Uu/EX6S  
{//nSplitter的缺省值为5 Dol{y=(3e  
//default value of nSplitter is 5 DBB&6~;?  
this("","","",5); A"&<$5Q  
} ;5.&TQT  
-,b+tC<V)0  
=#[oi3k  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;m#4Q6k)V?  
{ prN+{N8YC  
sSiteURL= sURL; Ikf[K%NKn  
sFilePath = sPath; b^C27s  
sFileName = sName;
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this.nSplitter = nSpiltter; .kg 3>*  
*j&)=8Y|   
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} Z:7eroZP  
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public String getSSiteURL() c+e?xXCEAz  
{ W"_<SYVJ  
return sSiteURL; [bP^RY:  
} eBnx$  
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E5)0YYjHZ  
public void setSSiteURL(String value) <A8>To<  
{ 6V]m0{:E  
sSiteURL = value; :,aY|2si  
} Sk>=C0f:  
!pw)sO~  
Vi-Ph;6[  
public String getSFilePath() \q1tT!]  
{ $1|E(d1  
return sFilePath; Vez8~r3  
} N;'c4=M~(  
 jK]1X8  
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public void setSFilePath(String value) cI\[)5&  
{ =dDPQZEin  
sFilePath = value; `sT;\  
} ,P`NtTN-  

/
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jL^@;"/XhC  
public String getSFileName() czD"mI!  
{ 2I}pX9  
return sFileName; ,7Hyrx`  
} aF^NYe  
94ruQ/   
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public void setSFileName(String value) }8
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{ 7GsKD=bl]  
sFileName = value; ~W8Xg)  
} Uc {m##!  
8R3{
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sV a0eGc  
public int getNSplitter() \Dq'~ d  
{ rN}
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return nSplitter; KoNu{TJ  
} N~8H\  
,.QJS6Yv  
8.B'O>\T  
public void setNSplitter(int nCount) }^Q:Q\  
{ Mt-r`W3 q  
nSplitter = nCount; `_OrBu[  
} 8A3/@Z;0S  
} #\l
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ylZQwICk  
/* .5G`Y  
**Utility.java jjj<B
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*/ ;(/go\m tB  
package NetFox; "Bf8mEmp  
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public class Utility { 5N|LT8P}Z  
-[-oz0`Sl{  
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public Utility() ewk7:zS/?  
{ JpfA+r  
>[;@ [4}  
5;0w({1l  
} -/JEKwc  
(^}t  
//线程睡眠 ?lsK?>uU  
public static void sleep(int nSecond) !\7`I}:  
{ xyGwYv>*KO  
try{ 34u[#O{2  
Thread.sleep(nSecond); cr!W5+r  
} V)<>W_g  
catch(Exception e) XY'8oU`]{  
{ R<&Euph  
e.printStackTrace (); +ausm!~6  
} I </P_:4G  
} sq_>^z3T  
j;-Wf6h{  
//日志 R xITMt  
public static void log(String sMsg) _ l`F}v  
{ !+PrgIp>  
System.err.println(sMsg); lw9jk`7^  
} OOSf<I*>  
_C/|<Ot:  
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public static void log(int sMsg) G7 UUx+X  
{ ['}|#
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System.err.println(sMsg); ML12&E>  
} |KYl'"5\  
} XZ |L D#  
:.+w'SEn4M  
{:gx*4}q8  
/* HqWWWCWal  
**TestMethod.java #AGO~#aK  
*/ S!8<|WO^t  
package NetFox; uBbQJvL  
.Od:#(aq  
:b44LXKCP  
public class TestMethod { ~DK.Y   
x *I'Ar  
0(y*EJA$  
public TestMethod() M
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{ ///xx/weblogic60b2_win.exe 3HrG^/  
try{ 7p.8{zQ*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }U_^zQfaj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7#E/Q~]'6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z{^!z  
fileFetch.start(); B46:LQ9[  
} n>v1<
^  
catch(Exception e){e.printStackTrace ();} *LB-V%{|'  
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Cb
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} "rn  
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public static void main(String[] args) nnPT08$  
{ \XB,)XDB  
new TestMethod(); swj\X,{  
} m
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} v)du]  
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