http断点续传简单实现（java)

/* RF.8zea{O`  
**SiteFileFetch.java tz"zQC$  
*/ b>"=kN/  
package NetFox; B3iU#  
import java.io.*; 9W@Tf  
import java.net.*; !JVpR]lWS  
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#u6ZCv7u  
public class SiteFileFetch extends Thread { +b6kU{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean MnymV;y"  
long[] nStartPos; //开始位置 Y'%k
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long[] nEndPos; //结束位置 ?g #4&z.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =f{YwtG  
long nFileLength; //文件长度 {`CmE/`{  
boolean bFirst = true; //是否第一次取文件 / qo`vk A  
boolean bStop = false; //停止标志 [P?.(*  
File tmpFile; //文件下载的临时信息 [ZkK)78}k  
DataOutputStream output; //输出到文件的输出流 k->cqtG  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ImVHX~qHJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException )r
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{ dTW3mF4=  
siteInfoBean = bean; q2KWSh
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); EkEU}2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pUXszPf  
if(tmpFile.exists ()) nXnO]wXC  
{ vx8-~Oq{|;  
bFirst = false; u4p){|x7s  
read_nPos(); v22ZwP  
} iH"
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else BSib/)p  
{ O
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nStartPos = new long[bean.getNSplitter()]; fA>FU/r  
nEndPos = new long[bean.getNSplitter()]; wX*F'r"z  
} 1P+Te,I  
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} |ydOi&  
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public void run() El)Wj
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{ Us*"g{PQ  
//获得文件长度 ^|0>&sTHOH  
//分割文件 qkbxa?&X  
//实例FileSplitterFetch IrZ!.5%tV  
//启动FileSplitterFetch线程 P<WCW3!JZ  
//等待子线程返回 p+>vX X  
try{ zgh~P^Z  
if(bFirst) /}=Bi-  
{ hB)TH'R{:  
nFileLength = getFileSize(); M} {'kK  
if(nFileLength == -1) 8bIwRVA2\  
{ b4HUgW3Ac  
System.err.println("File Length is not known!"); $-:j'e:j  
} pl.K*9+  
else if(nFileLength == -2) Qir
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{ ?pJUbZ#J  
System.err.println("File is not access!"); pZv>{=2hOS  
} \P` mV9P  
else aV'r oxM  
{ (]l}QR%Bxu  
for(int i=0;i<nStartPos.length;i++) {a `#O9  
{ {v>orP?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); pNzSy"Y$  
} IT\lkF2  
for(int i=0;i<nEndPos.length-1;i++) ADQ#qA,/  
{ ?QXc,*=N  
nEndPos = nStartPos[i+1]; O~W
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} ;=[~2*8  
nEndPos[nEndPos.length-1] = nFileLength; &:"[hU  
} m|5yET  
} bez_|fY{T  
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//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3\Ma)\>R\-  
for(int i=0;i<nStartPos.length;i++) g,N"o72)  
{ Mmu>&C\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7u9!:}Tu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &CEZ+\bA  
nStartPos,nEndPos,i); "}jY;d#n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 17nONhh  
fileSplitterFetch.start(); a8Q=_4 l  
} ,ruL7|T&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &XnbZ&_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %wYGI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", JNYFu0  
nEndPos = " + nFileLength); 5#SD$
^  
// fileSplitterFetch[nPos.length-1].start(); /v,H%8S  
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n 7Bua  
//等待子线程结束 2}^fhMS  
//int count = 0; 1|c\^;cTkt  
//是否结束while循环 9(PQ7}  
boolean breakWhile = false; #6%9*Rh  
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C {GSf`D!T  
while(!bStop) fq"<=  
{ ?xbPdG":R  
write_nPos(); i9FHEu_  
Utility.sleep(500); mar BVFz~  
breakWhile = true; eaI!}#>R+  
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for(int i=0;i<nStartPos.length;i++) _26~<gU8  
{ itmdY!;<  
if(!fileSplitterFetch.bDownOver) /5y*ZIq]e  
{ )fo9Qwe  
breakWhile = false; >,Zf3M  
break; UaQR0,#0y  
} +Xg]@IS-eg  
} h* to%N  
if(breakWhile) AJ*FQo.U  
break; 3 oG5E"G  
n2JwZ?  
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//count++; n' \poB?  
//if(count>4) FD&"k=p+X  
// siteStop(); Wy2 pa #Q  
} S]7RGzFe  
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_;Q1PgT  
System.err.println("文件下载结束！"); lUR7zrwJ]o  
} G@O~*k1v  
catch(Exception e){e.printStackTrace ();} <L1;aNN  
} ].j;d2xT\  
i5>]$j1/  
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//获得文件长度 O+Zt*
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public long getFileSize() .5',w"R  
{ f,?P1D\  
int nFileLength = -1; ]&')#YO  
try{ c:/H}2/C  
URL url = new URL(siteInfoBean.getSSiteURL()); >^8=_i !  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =c-,uW11[  
httpConnection.setRequestProperty("User-Agent","NetFox"); MMMuT^X  
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int responseCode=httpConnection.getResponseCode(); 5s >UM@})  
if(responseCode>=400) d
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{ nQ0g,'o  
processErrorCode(responseCode); F0O/SI(cA  
return -2; //-2 represent access is error a|*{BlY  
} Hq{i-z+  
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String sHeader; Qz+hS\yx  
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for(int i=1;;i++) 5AWIk,[  
{ vpoeK'bi,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); liW0v!jBo  
//Utility.log(in.readLine()); qeK_w '  
sHeader=httpConnection.getHeaderFieldKey(i); 1CkBfK  
if(sHeader!=null) l@x/{0  
{ ,Qgxf';+$  
if(sHeader.equals("Content-Length")) y^o*wz:D*  
{ 5$,dpLbL  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hcvWf\4'#q  
break; >i>%
@  
} jXBAo  
} &TmN^R>  
else #PzRhanX  
break; Q0)6 2[cMm  
} HMQi:s7%  
} Hoaf3 `n  
catch(IOException e){e.printStackTrace ();} ):@XMECa  
catch(Exception e){e.printStackTrace ();} 1rr\l`  
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Utility.log(nFileLength); %<|w:z$vp  
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return nFileLength; YxEc(a"  
} K5O#BBX=  
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//保存下载信息（文件指针位置） (p2jigP7a[  
private void write_nPos() w`kn!k8  
{ e12.suv  
try{ _H:mBk,,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]UR@V;JG  
output.writeInt(nStartPos.length); Pg]&^d&$  
for(int i=0;i<nStartPos.length;i++) 6]=$c<.&  
{ vZHm'  
// output.writeLong(nPos); de?Bn+mvi.  
output.writeLong(fileSplitterFetch.nStartPos); SjT8eH #  
output.writeLong(fileSplitterFetch.nEndPos); 3d qj:4[f  
} cxBu2(Y  
output.close(); os<B}D[  
} @z8,XW }  
catch(IOException e){e.printStackTrace ();} (x{
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catch(Exception e){e.printStackTrace ();} RR u1/nam  
} RT2%)5s  
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//读取保存的下载信息（文件指针位置） '%@fW
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private void read_nPos() ,O[HX?>  
{ "r6DZi(^K  
try{ }B=`nbgIG7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y)kO"  
int nCount = input.readInt(); :G/T{87H  
nStartPos = new long[nCount]; .w/_Om4T*b  
nEndPos = new long[nCount]; uyt]\zVT  
for(int i=0;i<nStartPos.length;i++) ]] R*sd*  
{ ('qu#.'  
nStartPos = input.readLong(); y$=$Yc&Ub  
nEndPos = input.readLong(); uqaP\  
} q[l!kC+Eh  
input.close(); H pHXt78  
}  FSaCbs(  
catch(IOException e){e.printStackTrace ();} ,J|8P{ZO  
catch(Exception e){e.printStackTrace ();} |Co
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} {5
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,qF;#nB-  
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private void processErrorCode(int nErrorCode) Ccmo(W+0  
{ (^fiw%#  
System.err.println("Error Code : " + nErrorCode); 4{?Djnh  
} UADD 7d  
oe<9CK:?>  
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//停止文件下载 F]e]  
public void siteStop() & 5!.!Z3  
{ 0{0|M8  
bStop = true;  jpcbW  
for(int i=0;i<nStartPos.length;i++) o1x IGP<  
fileSplitterFetch.splitterStop(); Q/oel'O*x  
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} 1'c  
} (1`z16  
//负责部分文件的抓取 2!Ip!IQ:  
**FileSplitterFetch.java N"X;aVFs_  
*/ ZP>KHiA  
package NetFox; a}~Xns  
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import java.io.*; 86bl'FdKS  
import java.net.*; Tx)X\&ij&  
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public class FileSplitterFetch extends Thread { F!FXZht$P  
1bW[RK;GE  
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String sURL; //File URL 1&S34wJF  
long nStartPos; //File Snippet Start Position 95Q{d'&  
long nEndPos; //File Snippet End Position `Zn2Vx  
int nThreadID; //Thread's ID {U:c95#.!S  
boolean bDownOver = false; //Downing is over qDR`)hle  
boolean bStop = false; //Stop identical iGG;  
FileAccessI fileAccessI = null; //File Access interface Y|eB;D
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException k 7 !{p  
{ H-&Z+4 +Xs  
this.sURL = sURL; E;[ANy4L  
this.nStartPos = nStart; 35}{dr  
this.nEndPos = nEnd; Y7QIFY's~  
nThreadID = id; FyZp,uD  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E^uWlUb{  
} iOCx7j{BS  
5

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public void run() 7_,)"J2^  
{ wB(A['k  
while(nStartPos < nEndPos && !bStop) uWs5+  
{ eK%~`Y  
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try{ u="VJ3
 
URL url = new URL(sURL); xHs8']*
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z)RoFD1]C  
httpConnection.setRequestProperty("User-Agent","NetFox");  4wLp  
String sProperty = "bytes="+nStartPos+"-"; %
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httpConnection.setRequestProperty("RANGE",sProperty); Z:Hk'|q}I  
Utility.log(sProperty); A"wor\(  
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InputStream input = httpConnection.getInputStream(); qT( 3M9!  
//logResponseHead(httpConnection); |Qq_;x]  
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byte[] b = new byte[1024]; < * )u\A  
int nRead; M" |Mte  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .Rq|F  
{ Jf<+VJ>t  
nStartPos += fileAccessI.write(b,0,nRead); L;a>J  
//if(nThreadID == 1) -]1
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }@-4*5P3  
} /b*VFA/75  
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Utility.log("Thread " + nThreadID + " is over!"); h=uv4&  
bDownOver = true; iV8j(HV  
//nPos = fileAccessI.write (b,0,nRead); G813NoS o  
} l1X&Nw1W  
catch(Exception e){e.printStackTrace ();} <mE)&7C  
} ,z6&k  
} ({/@=e x*  
%M+ID['K9/  
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//打印回应的头信息 bAIo5lr  
public void logResponseHead(HttpURLConnection con) 1-.UkdZ}  
{ AplXl=  
for(int i=1;;i++) vh8{*9+  
{ Eeemy*U  
String header=con.getHeaderFieldKey(i); vAW+ ,Rfj  
if(header!=null) _KSYt32N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); N :E7rtT,M  
Utility.log(header+" : "+con.getHeaderField(header)); h(aF>a\Z  
else fL[(;KcAa  
break; n GE3O#fv  
} ht8%A 1|  
} a=LjFpv/]  
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public void splitterStop() $E;`Y|r%WK  
{ # [c`]v  
bStop = true; ;IX3w:Aw  
} ~
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} o g.LD7&/  
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{9wBb`.n^  
/* Z/=x(I0  
**FileAccess.java Pyc/6~?  
*//文件访问(定位，写) {b4+ Yc  
package NetFox; (dO, +~  
import java.io.*; Rg! [ic !  
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public class FileAccessI implements Serializable{ 7T \}nX1  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SdF*"]t  
RandomAccessFile oSavedFile; x|/zn<\^  
long nPos; ?A7&SdJaO  
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public FileAccessI() throws IOException |s
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{ "7_6iB&@<  
this("",0); yE3g0@*  
} mO$]f4}  
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public FileAccessI(String sName,long nPos) throws IOException _iBNy   
{ i>gbT+*E!  
oSavedFile = new RandomAccessFile(sName,"rw"); GJW>8*&&(  
this.nPos = nPos; Hf P2o5-  
oSavedFile.seek(nPos); +JE h7  
} A@^e4\  
/I~iUND"G  
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public synchronized int write(byte[] b,int nStart,int nLen) HpI[Af}l  
{ mq@2zE`.(  
int n = -1; @D%H-X  
try{ @$ E&H`da  
oSavedFile.write(b,nStart,nLen); aML?$_6  
n = nLen; F$Q(2:w  
} F)4Y;;#  
catch(IOException e) &mj98  
{ {<7!=@j  
e.printStackTrace (); r (Ab+1b  
} +o)o4l%3  
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return n; )24r^21.q  
} `mV&[`NZ  
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} ^]}UyrOn  
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/* H8j#rC#&pm  
**SiteInfoBean.java !gv/jdF  
*/ G"&9u2k  
package NetFox; X $LX;Lv  
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public class SiteInfoBean { f]H[uzsV  
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private String sSiteURL; //Site's URL n2\;`9zm  
private String sFilePath; //Saved File's Path _SM5x,Zd  
private String sFileName; //Saved File's Name p b:mw$XQ7  
private int nSplitter; //Count of Splited Downloading File Uu xbN-u  
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public SiteInfoBean() [eI{vH{  
{//nSplitter的缺省值为5 Y3G$(+i8  
//default value of nSplitter is 5 ]MJyBz+k  
this("","","",5); HIP6L,$  
} KWIH5* AM  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) q6'3-@%  
{ Nqcmj
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sSiteURL= sURL; WT$m*I  
sFilePath = sPath; i8A{DMc,U  
sFileName = sName; ZaQgSE>Y  
this.nSplitter = nSpiltter; 
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} FH
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public String getSSiteURL() $PA=7`\MP/  
{ ;Hr FPx&d1  
return sSiteURL; |UvM[A|+  
} 37'@,*m`  
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public void setSSiteURL(String value) ,Oojh;P_  
{ WoGK05w  
sSiteURL = value; p#HbN#^Hy  
} "/6<k0.D&  
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public String getSFilePath() p@`rBzGp  
{ w8E6)wF=7  
return sFilePath; e _\]Q-  
} &U\Xy+  
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public void setSFilePath(String value) i1RU5IRy|j  
{ tX)l$oRPr  
sFilePath = value; b6%T[B B  
} iR j/Tm*T'  
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public String getSFileName() csZIBi  
{ Am=D kkP%  
return sFileName;  hM   
} 5m2(7FC%su  
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public void setSFileName(String value) 1{\{'EP{  
{ V*P3C5l  
sFileName = value; 7e$\|~<  
} kGhWr M  
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public int getNSplitter() sIQd}  
{ hYRGIpu5  
return nSplitter; 4?YhqJ  
} |eT?XT<=o  
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public void setNSplitter(int nCount) -FA]%Pl<'  
{ 8`E9a  
nSplitter = nCount; nnLE dJ}n  
}
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} Iw(2D(se  

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!Irmc*;QE  
/* LQ4GQqS*  
**Utility.java jSbO1go#  
*/ pVe@HJy6G  
package NetFox; V&4)B &W  
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public class Utility { J0xOB;rd  
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public Utility() ;8m_[gfw  
{ ypEcjVPD  
AkdONKO8{  
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} H|>dF)%pj  
q)R&npP7  
//线程睡眠 `[\*1GpAo  
public static void sleep(int nSecond) Ys,}L.  
{ v{4K$o  
try{ xXQ#?::m  
Thread.sleep(nSecond); oj*5m+:>a  
}  TA;  
catch(Exception e) 8mTjf Br  
{ `?VtB!p@x=  
e.printStackTrace (); :Bc)1^I  
} 1c);![O  
} De`)`\U  
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//日志 \IY)2C<e  
public static void log(String sMsg) T'.U?G  
{ p~1,[]k  
System.err.println(sMsg); 7m0sF<P{g  
} YGrmco?G  
+ 5E6|  
%.,-dV'  
public static void log(int sMsg) J^[>F{8!n  
{ ]0P-?O:  
System.err.println(sMsg); ,^,
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} b,kXV<KtU  
} Rb=
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/* \(Z'@5vC  
**TestMethod.java "o&_
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*/ xsS/)R?  
package NetFox; *njdqr2c~  
/NFv?~</k  
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public class TestMethod { A `\2]t$z  
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v>zeK  
public TestMethod() I$sJ8\|gw'  
{ ///xx/weblogic60b2_win.exe LY}%|w  
try{ vgRjd1k.\y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &L}e&5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0-#SvTf>;:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @? 4-  
fileFetch.start(); K~"uZa^s  
} Q#NXJvI  
catch(Exception e){e.printStackTrace ();} B0I(/ 7  
6wH]W+A  
9?<WRM3a>  
} =N,9#o6^  
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public static void main(String[] args) Arh0m. w  
{ y7aBF13Kl  
new TestMethod(); HHa XK  
} 1(0LX^%  
} TJ9JIxnS  
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