http断点续传简单实现（java)

/* Dd3f@b[WX  
**SiteFileFetch.java pwFp<O"  
*/ oV|O`n  
package NetFox;
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import java.io.*; XlmX3RU  
import java.net.*; Ltlp9 S  
]?9*Vr:P^  
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public class SiteFileFetch extends Thread { TOwd+]B  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]\E"oZ  
long[] nStartPos; //开始位置 y Zafq"o  
long[] nEndPos; //结束位置 du65=w4E!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 AIF?>wgq  
long nFileLength; //文件长度 > p`,  
boolean bFirst = true; //是否第一次取文件 qBA)5Sv\V  
boolean bStop = false; //停止标志 u'YXI="(  
File tmpFile; //文件下载的临时信息 u4x-GO
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DataOutputStream output; //输出到文件的输出流 18&"j 8'm  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *PJH&
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public SiteFileFetch(SiteInfoBean bean) throws IOException 5`;SI36"  
{ X! d-"[  
siteInfoBean = bean; bI):-2&s}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 'aSsyD!?<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :F(4&e=w  
if(tmpFile.exists ()) .OPknC  
{ c<lp<{;  
bFirst = false; 
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read_nPos(); "1O_h6C  
} !)s(Lv%]  
else &<&tdShI  
{ v%tjZ5x  
nStartPos = new long[bean.getNSplitter()]; FP@_V-  
nEndPos = new long[bean.getNSplitter()]; 1p&.\^  
} Lg:1zC  
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} }$ y.qqG  
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public void run() I?T !  
{ 0s n$QmW:  
//获得文件长度 K\xz|Gq  
//分割文件 Fh~9(Y
#  
//实例FileSplitterFetch ]LE,4[VxRz  
//启动FileSplitterFetch线程 0h-NT\m  
//等待子线程返回 b
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try{ Q2CGC+   
if(bFirst) I4Do$&9<D  
{ Hav&
vV  
nFileLength = getFileSize(); LkbD='\=  
if(nFileLength == -1) #2=l\y-#  
{ 9Po>laT 5  
System.err.println("File Length is not known!"); .Xlo-gHk  
} rwWOhD)RU  
else if(nFileLength == -2) 2> a&m>  
{ Bg|d2,im  
System.err.println("File is not access!"); L*0YOE%=]  
} Z%~}*F}7X  
else z,Xj$wl  
{ xQR/Xp!h  
for(int i=0;i<nStartPos.length;i++) ^-%'ItVO  
{ L15)+^4n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \8(Je"S  
} :tWkK$  
for(int i=0;i<nEndPos.length-1;i++) r] /Ej!|  
{ O%t? -h  
nEndPos = nStartPos[i+1]; enk`I$Xx  
} N
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nEndPos[nEndPos.length-1] = nFileLength; R0t!y3r&N  
} %YVPm*J~  
} 6 ;'s9s"  
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m mF0RNE  
//启动子线程 :EW1I>}_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rBJ`=oz  
for(int i=0;i<nStartPos.length;i++) E8C8kH]  
{ ?0)K[Kd'Y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &D<6Go/)_*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `yR/M"u6T  
nStartPos,nEndPos,i); =1Plu5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x
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fileSplitterFetch.start(); #x 6/"Y2  
} oVK?lQ~y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "]3o933D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Aa-5k3:x]=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5$i(f8*  
nEndPos = " + nFileLength); V;^-EWNj  
// fileSplitterFetch[nPos.length-1].start(); E2|M#Y  
o^@#pU <  
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//等待子线程结束 {~&]  
//int count = 0; r@JMf)a]  
//是否结束while循环 PY|zN|  
boolean breakWhile = false; R(t%/Hvs$  
<\nM5-wR  
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while(!bStop) J"#6m&R_q  
{ E2l"e?AN~  
write_nPos(); eP (*.  
Utility.sleep(500); L@RnLaoQ  
breakWhile = true; >07i"a  
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em7L`,  
for(int i=0;i<nStartPos.length;i++) Dj= {%  
{ xTk6q*NvT^  
if(!fileSplitterFetch.bDownOver) foPM5+.G  
{ ,&Zp^  
breakWhile = false; i=5!taxu}E  
break; FoE}j   
} uf]wX(*<k  
} yl*%P3m|  
if(breakWhile) =H: N!!:  
break; *s, bz.[  
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//count++; K}q5,P(  
//if(count>4) C
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// siteStop(); Ag3+z+uS  
} uJ|,-"~F  
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UQhD8Z'I.  
System.err.println("文件下载结束！"); ?AO=)XV2  
} F)=<|,b1  
catch(Exception e){e.printStackTrace ();} EWl9rF@I  
} ']Czn._  
|-v/  
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//获得文件长度 uR=*q a  
public long getFileSize() ]
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{ >;G7ty[RX7  
int nFileLength = -1; Dd OK&  
try{ W-D4" G@  
URL url = new URL(siteInfoBean.getSSiteURL()); =C#z Px,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a@_n>$LZL  
httpConnection.setRequestProperty("User-Agent","NetFox"); l"&iSq!3=  
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int responseCode=httpConnection.getResponseCode(); ~hP]<$v  
if(responseCode>=400) >7?Lq<H  
{ zzC{I@b
 
processErrorCode(responseCode); Y3V2}  
return -2; //-2 represent access is error `^g-2~  
} EE9eG31|r  
4X:mb}(  
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String sHeader; mmC
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for(int i=1;;i++) ju.`c->k"  
{ 2_6
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Oxi^&f||`  
//Utility.log(in.readLine()); 25vq#sS]  
sHeader=httpConnection.getHeaderFieldKey(i); 9)F$){G]vs  
if(sHeader!=null) $?&distJ  
{ S>
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if(sHeader.equals("Content-Length")) mt
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{ \  6Y%z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); uE#"wm'J  
break; h?QGJ^#8  
} t,5AoK/NL9  
} khP Ub,  
else w~AO;X*Ke"  
break; <?rd
hx  
} P!R`b9_U  
} 4?`*#DPl  
catch(IOException e){e.printStackTrace ();} !'bZ|j%  
catch(Exception e){e.printStackTrace ();} tac_MtW?  
C
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Utility.log(nFileLength); /7R0w  
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return nFileLength; SQdK`]4  
} 'V4B{n7h  
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YB9)v5Nz(  
//保存下载信息（文件指针位置） xqj@T^y  
private void write_nPos() opReAU'I  
{ RbEtNwG@c  
try{ 1VPxCB\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5BM
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output.writeInt(nStartPos.length); DPWnvd  
for(int i=0;i<nStartPos.length;i++) /,9n1|FrG  
{ <[z9*Tm  
// output.writeLong(nPos); Y-y}gc_L  
output.writeLong(fileSplitterFetch.nStartPos); l Ztw[c  
output.writeLong(fileSplitterFetch.nEndPos); {%v{iE>  
} {G-y7y+
E  
output.close(); %hA0  
} Ix.Y_}  
catch(IOException e){e.printStackTrace ();} <OGXKv@  
catch(Exception e){e.printStackTrace ();} ^}Gu'!z9D  
} EE~DU;p;]  
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//读取保存的下载信息（文件指针位置） M
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private void read_nPos() `6Yk-5  
{ T:VFyby\w  
try{ Y-P?t
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $G#)D^-5G  
int nCount = input.readInt(); Y#oY'S .;y  
nStartPos = new long[nCount]; 3W@ta1  
nEndPos = new long[nCount]; =BgQSs/^c  
for(int i=0;i<nStartPos.length;i++) tzG.)Uqs  
{ F t;[>o  
nStartPos = input.readLong(); &}b-aAt  
nEndPos = input.readLong(); I~>Ye<g#  
} `;3fnTI:1  
input.close(); \aGTi pB  
} f5vsxP)Y[  
catch(IOException e){e.printStackTrace ();} w*IDL0#  
catch(Exception e){e.printStackTrace ();} &&|c-mD+*  
} LVNJlRK  
>?^_JEC6  
3/RNStd<L!  
private void processErrorCode(int nErrorCode) _iZ9Ch\  
{ Y2P%0
 
System.err.println("Error Code : " + nErrorCode);  pytF K)U  
} f/%QMhM:  
ivP#qM1*;  
/\UFJ  
//停止文件下载 PG'+vl  
public void siteStop() W4S! rU  
{ hD>cxo  
bStop = true; {Nny.@P)H  
for(int i=0;i<nStartPos.length;i++) S2"HE`  
fileSplitterFetch.splitterStop(); U<.,"`=l  
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} ^n<o,K4\}  
} 61&A`  
//负责部分文件的抓取 l5CFm8%  
**FileSplitterFetch.java (z.eXoP@>  
*/ rCgoU xW`  
package NetFox; J(=io_\bO  
:
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import java.io.*; N9gbj%+  
import java.net.*; *_!}g ]  
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public class FileSplitterFetch extends Thread { B0"55g*c  
y:ad%,. C  
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String sURL; //File URL Tt\G
y  
long nStartPos; //File Snippet Start Position 7':qx}c#!1  
long nEndPos; //File Snippet End Position l"1at eM3  
int nThreadID; //Thread's ID HMPb%'U~  
boolean bDownOver = false; //Downing is over KkD&|&!Q7u  
boolean bStop = false; //Stop identical [7@9wa1v!  
FileAccessI fileAccessI = null; //File Access interface e)A-.SRiO$  
U6yZKK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 'fr~1pmx#3  
{ k;xIo(:  
this.sURL = sURL; ,RIC _26  
this.nStartPos = nStart; ERz{, >
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this.nEndPos = nEnd; L5 Q^cY]p  
nThreadID = id; 
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 N97
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} 4c9a"v  
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public void run() ^\C Fke=  
{ !yo@i_1D  
while(nStartPos < nEndPos && !bStop) $L"h|>b\o  
{ 8T?D#,/  
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try{ gAr=fq-|  
URL url = new URL(sURL); ?4cj
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Jp"yb`w  
httpConnection.setRequestProperty("User-Agent","NetFox"); XJe}^k  
String sProperty = "bytes="+nStartPos+"-"; }*?,&9/_)  
httpConnection.setRequestProperty("RANGE",sProperty); +=K =B  
Utility.log(sProperty); 3nnoXc'  
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InputStream input = httpConnection.getInputStream(); \wF-[']N  
//logResponseHead(httpConnection); #7['M;_  
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l
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byte[] b = new byte[1024]; 7KL@[  
int nRead; Y49&EQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?azcWf z0  
{ 3?e~J"WXC5  
nStartPos += fileAccessI.write(b,0,nRead); K5^`,}Q^  
//if(nThreadID == 1) 1YNw=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 
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} WG*),P?  
b|e1HCH  
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Utility.log("Thread " + nThreadID + " is over!"); q_cP<2`@V  
bDownOver = true; ;Z); k`j  
//nPos = fileAccessI.write (b,0,nRead); 9oYE  
} +ZOK
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catch(Exception e){e.printStackTrace ();} =0az5td  
} }N&?8s=  
} QP/ZD|/ t1  
/cT6X]o8  
q%LjOPE V  
//打印回应的头信息 [&g"Z"  
public void logResponseHead(HttpURLConnection con) &\%\"Zh  
{ 4n"6<cO5q  
for(int i=1;;i++) ;;6$d{  
{ $[Q;{Q  
String header=con.getHeaderFieldKey(i); /24}>oAH  
if(header!=null) rp+]f\]h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @lWYc`>}  
Utility.log(header+" : "+con.getHeaderField(header)); *d`KD64  
else QQHQ3\  
break; 1tLEKSo+  
} AGm=0Om  
} E]v?:!!ds  
Gu@C*.jj!  
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public void splitterStop() XOLE=zdSp  
{ Npi)R)  
bStop = true; `5e{ec c7  
} s/B_  
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} $s4.A
j  
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/* yM7Iq)o6u  
**FileAccess.java =H3tkMoi2  
*//文件访问(定位，写) ;>L8&m)R5  
package NetFox; QM* T?PR  
import java.io.*; Oet+$ b  
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eWNg?*/  
public class FileAccessI implements Serializable{ #4lIn
a%VX  
!/!ga)Y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o.kDOqd  
RandomAccessFile oSavedFile; d^J)Mhju  
long nPos; k}p8"'O  
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7~F~'
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public FileAccessI() throws IOException ".%d{z}vz  
{ 7RWgc]@?>  
this("",0); co3\1[q"b  
} )UM^#<-  
RgA"`p7{  
3z(4axH'  
public FileAccessI(String sName,long nPos) throws IOException yi*EobP  
{ !yxqOT-  
oSavedFile = new RandomAccessFile(sName,"rw"); ]d-.Mw,'  
this.nPos = nPos; W7 dSx  
oSavedFile.seek(nPos); fggs ;Le  
} kaXq.  
v&'#Gg  
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public synchronized int write(byte[] b,int nStart,int nLen) /KX+'@  
{ Qj;{Z*l%+  
int n = -1; &H]/'i-  
try{ pm,xGo2  
oSavedFile.write(b,nStart,nLen); L/r_MtN  
n = nLen; ~bxev/$d  
} *dw.Ug  
catch(IOException e) |Ia9bg'1U  
{ Jp_#pV*}:  
e.printStackTrace (); |[IyqWG9  
} M@{#yEP  
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return n; >*8V]{f9  
} DkEv1]6JI_  
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} UGI<
V!  
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/* ~qrSHn}+PU  
**SiteInfoBean.java `.@sux!lu  
*/ +h4W<YnW  
package NetFox; <[cpaZT,  
ERV]N:(  
)6C+0b*  
public class SiteInfoBean { ?gl&q+mv  
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u  
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private String sSiteURL; //Site's URL ,UMr_ e{|  
private String sFilePath; //Saved File's Path &Mk!qE<:N  
private String sFileName; //Saved File's Name %S^hqC  
private int nSplitter; //Count of Splited Downloading File p
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wW@e#:  
*x|%Nua"  
public SiteInfoBean() *9EwZwE_K  
{//nSplitter的缺省值为5 FOsd{Fw  
//default value of nSplitter is 5 nc k/Dw  
this("","","",5); F,wB6Cw  
} e$Ds2%SaT  
T+}|$/Tv  
6:#o0OeBP  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O8@65URKx  
{ $72eHdy/yl  
sSiteURL= sURL; 6(bN*.  
sFilePath = sPath; Yub}AuU`v  
sFileName = sName; T(D6'm:X  
this.nSplitter = nSpiltter; iWf+wC|  
wf\"&xwh?  
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} x|~8?i$%  
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public String getSSiteURL() rv*{[K  
{ s|Mo3_>  
return sSiteURL; SsZC g#i  
} X
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`MOw\Z)..  
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public void setSSiteURL(String value) fs'SCwx  
{ !cyrt<  
sSiteURL = value; 1!v{#w{u7  
} 0Qt!w(  
HoGYgye=  
PEf yHf7`  
public String getSFilePath() k:Pn.<  
{ >3uNh:|>/  
return sFilePath; J?8Mo=UZz  
} 8Sr'  
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public void setSFilePath(String value) y8k8Hd1<f  
{ GmHDG-  
sFilePath = value; h3
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} [H}> 2Q  
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public String getSFileName() ~Gu$EqQ  
{ q?}C`5%D  
return sFileName; Dkz/hg:q  
} <YaTr9%w  
~1uQyt  
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public void setSFileName(String value) 3`^@
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{ G4cgY|71  
sFileName = value; 1h$?,  
} Nz dN4+  
Z`S#> o  
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public int getNSplitter() 0g?)j-  
{ +RooU?Aq  
return nSplitter; ;,f\Wf"BW  
} ]fM|cN8(zM  
gNCS*a  
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public void setNSplitter(int nCount) ~:DL{ZeEb  
{ _?~%+Oz/  
nSplitter = nCount; 47q> q  
} rwP#Yj[BK+  
} b$_81i  
nTy]sPn  
HRf;bKZ  
/* 6w^P{%ul  
**Utility.java 'UlVc2%
{  
*/ =QqH`.3  
package NetFox; :G _  
"hk#pQ  
P 9?cp{
*  
public class Utility { oZBD.s  
;R?@ D]  
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public Utility() Hyb(.hlZh  
{ J"r?F0  
2"ax*MQH<^  

X*2W4udF  
} @](vFb  
UoT`/.  
//线程睡眠 `zQuhD 8W  
public static void sleep(int nSecond) fL*7u\m:  
{ AB3_|Tza~&  
try{ & zDuh[j}  
Thread.sleep(nSecond); 2zC4nF)>O  
} Qq,2V
 
catch(Exception e) 6GxLaI  
{ 5JzvT JMx  
e.printStackTrace (); Q#g`D,:o%~  
} 6 >kULp  
} )iN;1>  
0*{(R#  
//日志 NUsx
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public static void log(String sMsg) &=@{`2&  
{ e9LX0=  
System.err.println(sMsg); x9l7|G/$  
}
7#LIGr  
5 ^{~xOM5  
t'44X  
public static void log(int sMsg) U)(R
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{ Fd9[Pe@?`  
System.err.println(sMsg); _(m72o0g>>  
} p(F@lL-  
} -@N-i$!;J  
6"-$WUlg  
7By7F:[b  
/* tJ(xeb  
**TestMethod.java _pdKcE\X  
*/ !gXxM,R  
package NetFox; $?GggP d  
$LXa]  
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public class TestMethod { hU
MG}<  
ifn=De3+  
3bRxV @0.  
public TestMethod() +5y^c|L0  
{ ///xx/weblogic60b2_win.exe j7!u;K^c  
try{ VEWW[T  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )\+Imn  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !U`4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?N{\qF1Mz  
fileFetch.start(); >iTmILA  
} alJ0gc
2?  
catch(Exception e){e.printStackTrace ();} ,hzRqFg2  
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>.wZEQ6QK  
} *R6lK&  
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public static void main(String[] args) ^wy  
{ 1Ek3^TOv7  
new TestMethod(); _9BL7W $;  
} "~Fg-{jM%  
} 2$JZ(qnN  
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