http断点续传简单实现（java)

/* +9fQ YJBA  
**SiteFileFetch.java Kt*kARN?  
*/ ;x
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package NetFox; =cwdl7N&I  
import java.io.*; n~mP7X%wE7  
import java.net.*; k;~*8i=%,\  
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public class SiteFileFetch extends Thread { :RG=3T[  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 9Z^\b)x  
long[] nStartPos; //开始位置 }xb?C""q^q  
long[] nEndPos; //结束位置 C.(<IcSG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 RemjiCE0'  
long nFileLength; //文件长度 h}n?4B~Gi  
boolean bFirst = true; //是否第一次取文件 M=t;t0  
boolean bStop = false; //停止标志 j9g0k<eg  
File tmpFile; //文件下载的临时信息 4V7=VZ,@3  
DataOutputStream output; //输出到文件的输出流 9?Q0O\&uP  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） XQI!G_\+C  
public SiteFileFetch(SiteInfoBean bean) throws IOException !+Zso&  
{ ?(E?oJ)(  
siteInfoBean = bean; PmlQW!gfBi  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Yy4l -}"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); axL
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if(tmpFile.exists ()) &ZAc3@l[c  
{ p^i]{"sjbU  
bFirst = false; vC_O!2E  
read_nPos(); ]]lM)  
} V|G
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else =*Y=u6?  
{ %QKRl5RM-  
nStartPos = new long[bean.getNSplitter()]; @iD5
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nEndPos = new long[bean.getNSplitter()]; h2
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} M=aWL!nJ  
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} %<Q?|}  
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public void run() 2o5v{W  
{ ^v].mV/  
//获得文件长度 ;qF#!
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//分割文件 +T@a/(Gl  
//实例FileSplitterFetch `+(|$?Cu  
//启动FileSplitterFetch线程 _,M:"3;Z  
//等待子线程返回 ToHCS/J59  
try{ = ?hx+-'  
if(bFirst) G;%Pf9o26  
{ vZns,K#4H\  
nFileLength = getFileSize(); >cPB:kD'  
if(nFileLength == -1) =*YK6  
{ D~xUr)E  
System.err.println("File Length is not known!"); {&Fh$H!  
} +{j? +
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else if(nFileLength == -2) Pe !eID8  
{ RJ_ratKN*g  
System.err.println("File is not access!"); kxg]sr"  
} U$`)|/8  
else 2dr[0
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{ 2b]'KiX  
for(int i=0;i<nStartPos.length;i++) qG/a5i  
{ rZy38Wo  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w 1
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} @awaN  
for(int i=0;i<nEndPos.length-1;i++) $+
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{ 6?0^U 9  
nEndPos = nStartPos[i+1]; FV/X&u8~  
} |Mp_qg?g  
nEndPos[nEndPos.length-1] = nFileLength; OH28H),}  
} D4m2*%M  
} W&]grG2/  
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}B_n}<tjD  
//启动子线程 7;C9V`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _1c'~;  
for(int i=0;i<nStartPos.length;i++) 8kih81tx"U  
{ /c`)Er6d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8 F'i5i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), AjaG.fa]k  
nStartPos,nEndPos,i); r6Z&i^cMe  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]do0{I%\eq  
fileSplitterFetch.start(); <>f  
} >Ge&v'~_|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0gV
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Um\Nd#=:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", j?6%=KuX<  
nEndPos = " + nFileLength);  |Gjd  
// fileSplitterFetch[nPos.length-1].start(); w&v_#\T  
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//等待子线程结束 2"nd(+QH  
//int count = 0; ]}F_nc2L  
//是否结束while循环 K2L+tw  
boolean breakWhile = false; Mno4z/4{A  
>E?626*  
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while(!bStop) A75IG4]  
{ !:`QX\Ux  
write_nPos(); GfY!~J  
Utility.sleep(500); !yH&l6s  
breakWhile = true; ZSYXUFz  
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for(int i=0;i<nStartPos.length;i++) R{@WlkG}  
{ ?`,UW;Br6  
if(!fileSplitterFetch.bDownOver) ;04doub  
{ cy?u *  
breakWhile = false;  F[115/  
break; hp,bfcM  
} Az6f I*yP  
} ,;H)CUe1"  
if(breakWhile) >!wX%QHH  
break; UL(R/yc  
<"AP&J'H  
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//count++; e0+N1kY  
//if(count>4) e!ar
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// siteStop(); c&AA< 6pkv  
} =wPl;SDf!  
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System.err.println("文件下载结束！"); br
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} _*9eAeJ  
catch(Exception e){e.printStackTrace ();} ]gHw;ry  
} i=.zkIjSh  
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//获得文件长度 :|M0n%-X  
public long getFileSize() Obrv5%'  
{ 5"c
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int nFileLength = -1; !CTchk<{(  
try{ BE:HO^-.1  
URL url = new URL(siteInfoBean.getSSiteURL()); /^i7^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C\j|+s  
httpConnection.setRequestProperty("User-Agent","NetFox"); :7<spd(%"  
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int responseCode=httpConnection.getResponseCode(); \eT0d<  
if(responseCode>=400) ga?.7F  
{ )Pakb!0H@t  
processErrorCode(responseCode); #O/ihRoaO  
return -2; //-2 represent access is error =m:xf&r#  
} HO/Ij  

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String sHeader; xJa  
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for(int i=1;;i++) c]v$C&FX  
{ Cz-eiPlq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q35$GFj"jD  
//Utility.log(in.readLine()); )/1AF^ E  
sHeader=httpConnection.getHeaderFieldKey(i); ?]]>WP  
if(sHeader!=null) MxD,xpf  
{ |77.Lqqy,  
if(sHeader.equals("Content-Length")) "9jt2@<  
{ `|Pfa  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [`BMi-WQ  
break; {~_X-g5|]  
} {Xb 6wQ"  
} WUm83"  
else ~,WG284  
break; e;GLPB  
} \  $;E,  
} {?!=~vp  
catch(IOException e){e.printStackTrace ();} :hr% 6K7  
catch(Exception e){e.printStackTrace ();} 9fj3q>Un,  
 $A]2Iw!&  
}:<`L\8q\  
Utility.log(nFileLength); *pK bMG#  
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return nFileLength; Mrysy)x  
} I(tMw6C$:  
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//保存下载信息（文件指针位置） e&sZ]{uD  
private void write_nPos() yB0xa%  
{ }K':tX?  
try{ xucrp::g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s.7\?(Lg  
output.writeInt(nStartPos.length); `Sgj!/!F  
for(int i=0;i<nStartPos.length;i++) yw2Mr+9I  
{ d5
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// output.writeLong(nPos); N3dS%F,_  
output.writeLong(fileSplitterFetch.nStartPos); {w:*t)@j  
output.writeLong(fileSplitterFetch.nEndPos); Pxf
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} OH.^m6Z  
output.close(); vP6NIcWC3  
} a,mG5bQ!  
catch(IOException e){e.printStackTrace ();} yvR3
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catch(Exception e){e.printStackTrace ();} S:2M9nC  
} r
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//读取保存的下载信息（文件指针位置） &!i'Q;q  
private void read_nPos() v~E\u  
{ 7Z%EXDm4/c  
try{ )(bAi  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1i=lJmr  
int nCount = input.readInt(); %!DdjC&5*  
nStartPos = new long[nCount]; T:FaD V{  
nEndPos = new long[nCount]; <[.{aj]QV  
for(int i=0;i<nStartPos.length;i++)
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{ ?e=3G4N  
nStartPos = input.readLong(); 9;2{=,  
nEndPos = input.readLong(); 10tlD<eYb  
} ^.3(o{g  
input.close(); $ljzw@k  
} LV}Z[\?  
catch(IOException e){e.printStackTrace ();} BjX*Gm6l  
catch(Exception e){e.printStackTrace ();} +"}#4  
} #*;G8yV  
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private void processErrorCode(int nErrorCode) !2=m |,  
{ Gx)U~L$B  
System.err.println("Error Code : " + nErrorCode); M
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} `@<>"ff#F  
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//停止文件下载 3A&: c/  
public void siteStop() x*'2%3C~  
{ {!0f.nv  
bStop = true; +HDfEo T  
for(int i=0;i<nStartPos.length;i++) .@KI,_X6,  
fileSplitterFetch.splitterStop(); r;n^\[Ov0,  
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} hQb3 8W[  
} '_q&~M{  
//负责部分文件的抓取 tUGnp'r  
**FileSplitterFetch.java ,DL%oQR  
*/ 5M v<8P~  
package NetFox; MA1y@  
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import java.io.*; =w;~1i%.k  
import java.net.*; :pJKZ2B,  
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public class FileSplitterFetch extends Thread { oUd R,;h9  
FZBdQhYF  
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String sURL; //File URL w~AW( VX  
long nStartPos; //File Snippet Start Position w# R0QF  
long nEndPos; //File Snippet End Position (jI
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int nThreadID; //Thread's ID xL
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boolean bDownOver = false; //Downing is over 6s.>5}M!  
boolean bStop = false; //Stop identical Ghf/IXq#  
FileAccessI fileAccessI = null; //File Access interface  9dCf@5]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 'wA4yJ<  
{ frRO?  
this.sURL = sURL; v"YaMbu  
this.nStartPos = nStart; X1XmaO%A  
this.nEndPos = nEnd; nN%Zed2O@6  
nThreadID = id; N{&Hq4^c  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {d '>J<Da  
} BHf7\+Ul  
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public void run() ^&7gUH*v  
{ rVM?[_'O
 
while(nStartPos < nEndPos && !bStop) ne|N!!Dmk  
{ pGcijD  
|>/m{L[  
#BW:*$>}  
try{ =rN_8&  
URL url = new URL(sURL); 3S"kw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); , Y^GQ`~#  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ksff]##H  
String sProperty = "bytes="+nStartPos+"-"; 4Z0Y8y8)  
httpConnection.setRequestProperty("RANGE",sProperty); ]sDlZJX<M  
Utility.log(sProperty); J+uz{  
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InputStream input = httpConnection.getInputStream(); HX#$ ^@Q(  
//logResponseHead(httpConnection); WelB"L  
$T7(AohR  
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byte[] b = new byte[1024]; oAF#bj_f  
int nRead; TG6E^3a P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xM_+vN*(  
{ \# _w=gs<i  
nStartPos += fileAccessI.write(b,0,nRead); ]p*Fq^  
//if(nThreadID == 1) Vrt*,R&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $bF3v=u`  
} YSr
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do DpTwvh  
Utility.log("Thread " + nThreadID + " is over!"); $H"(]>~  
bDownOver = true; H{g&yo  
//nPos = fileAccessI.write (b,0,nRead); Lnc>O'<5P9  
} J0UF(  
catch(Exception e){e.printStackTrace ();} T7Qw1k  
} ^oDSU7j5,  
} m^KK #Hw/`  
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//打印回应的头信息 o{OY1 ;=6  
public void logResponseHead(HttpURLConnection con) Eb89B%L62G  
{ 9uW\~DwsZ%  
for(int i=1;;i++) \*\)zj*r  
{ 0[R7HX-@  
String header=con.getHeaderFieldKey(i); 6
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if(header!=null) F!cRx%R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'Omj-o'tn9  
Utility.log(header+" : "+con.getHeaderField(header)); .Lp\Jyegs  
else =-;J2Qlg6  
break; %<h+_(\
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} ?dY|,_O  
} a[7Lqu  
3?s1Yw>?  
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public void splitterStop() Qn`Fq,uvL  
{ S\ ) ~9?  
bStop = true; wg=-&
-  
} c3C<P  
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} 8}{W.np_  
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/* Kq;s${ |G  
**FileAccess.java M`tNY
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*//文件访问(定位，写) ~ }?*v}  
package NetFox; %)sG 34  
import java.io.*; X*e<g=  
5'S~PQka*  
.{4U]a;[  
public class FileAccessI implements Serializable{ M7\yEi"*  
|6GDIoZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #SqU>R  
RandomAccessFile oSavedFile; i2 G.<(3O  
long nPos; /7hC /!@  
!b8.XGo  
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public FileAccessI() throws IOException v6KRE3:V  
{ LW*v/`@  
this("",0); XY!0yAK(!  
} Z^O_7I<5E  
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public FileAccessI(String sName,long nPos) throws IOException m.w.h^f$&  
{ BTDUT%Yfg  
oSavedFile = new RandomAccessFile(sName,"rw"); Lb}$)AcC  
this.nPos = nPos; @k3xk1*  
oSavedFile.seek(nPos); Y|~+bKa  
} B;c2gu  
aM|;3j1p  
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public synchronized int write(byte[] b,int nStart,int nLen) @ ('/NjTZ  
{ ZiaHLpk  
int n = -1; f]48>LRE8  
try{ XB;C~:  
oSavedFile.write(b,nStart,nLen); rObg:(z&\  
n = nLen; GL'l "L  
} T.pc3+B8N  
catch(IOException e) &9F(C
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{ ].HHTCD`c  
e.printStackTrace (); 4KB>O)YNg'  
} bE6bx6=u  
U o[\1)  
v/x~L$[  
return n; Dy|)u1?  
} ;S+]Z!5LT  
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} ";;Nc>-Y  
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/* D\^\_r):  
**SiteInfoBean.java s2"<<P[q'  
*/ *;[g Ga~  
package NetFox; cf,^7,-`"  
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public class SiteInfoBean { b=XXp`h~a  
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=[LUOOR*]  
private String sSiteURL; //Site's URL S!
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private String sFilePath; //Saved File's Path w5;d/r<q  
private String sFileName; //Saved File's Name z!aU85y  
private int nSplitter; //Count of Splited Downloading File '$5Qdaj  
Xxr"Gc[  
RC!9@H5S#  
public SiteInfoBean() 9QHV%%  
{//nSplitter的缺省值为5 z[WdJN{  
//default value of nSplitter is 5 p4vX3?&1W  
this("","","",5); ={\9-JJhE  
} cC]lO  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |O{kv}YZ  
{ +LF`ZXe8l  
sSiteURL= sURL; M8${&&[;  
sFilePath = sPath; e\.  
sFileName = sName; ]h'*L`  
this.nSplitter = nSpiltter; L:7 kp<E  
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W1ql[DqE{  
} vn
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Q2"K!u]  
public String getSSiteURL() eC`G0.op  
{ Z@0IvI  
return sSiteURL; vF9fX
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} .V@3zzv\  
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0~BZh%s< (  
public void setSSiteURL(String value) |Q$Dj!!1P  
{ wQYW5X  
sSiteURL = value; Q-KBQc  
} cToT_Mk  
|eqp3@Y1E  
''}2JJU{  
public String getSFilePath() 3cc;BWvM  
{ wZt2%+$6m  
return sFilePath; ,Bl_6ZaL  
} JZ/T:Hsh4  
HqXS-TG  
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public void setSFilePath(String value) W4=A.2[q  
{ =m6<H  
sFilePath = value; H__'K/nH+  
} %v[KLMo'(  
"Fz1:VV&  
DJ`xCs!R  
public String getSFileName() V0xO:7G^  
{ Y?:"nhN  
return sFileName; V!QC.D<  
} uG(XbDZZ1W  
`:W}yo<F  
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public void setSFileName(String value) $Y8iT<nP  
{ 4ULdf|oP"  
sFileName = value; cXK.^@du  
} qfF2S  
~-'-<-  
f |NXibmP  
public int getNSplitter() eE@7AM  
{ vJe c+a  
return nSplitter; fni7HBV?  
} ^(KDtc  
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public void setNSplitter(int nCount) nGxG!  
{ dw%g9DT  
nSplitter = nCount; u24XuSe$  
} TjOK8 t  
} MJU*Sq  
UTqKL*p523  
on 4 $n7  
/* #v*3-) 8  
**Utility.java oz7=1;r  
*/ %- Ga^[  
package NetFox; {FR+a**  
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~Xc1y!"9*  
public class Utility { h{^MdYJ  
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public Utility() 8:K_S a%  
{ k0
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gi+FL_8CzU  
} mteQRgC  
|(uo@-U  
//线程睡眠 .Dy2O*`  
public static void sleep(int nSecond) AR c  
{ -c#vWuLl  
try{ ,My'_"S?  
Thread.sleep(nSecond); ?8)k6:  
} lYU?j|n  
catch(Exception e) rd,!-
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{ 0> QqsQ  
e.printStackTrace (); qR kPl!5  
} 4wx{i6  
} oo1h"[  
{ITxHt  
//日志 DIgur}q)@  
public static void log(String sMsg) Th4}$)yrkN  
{ gFXz:!A  
System.err.println(sMsg); J\Tu=f)  
} pxCQ=0k  
hJ?PV@xy
 
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public static void log(int sMsg) [S0wwWU |0  
{ H%{k.#O  
System.err.println(sMsg); 9&s>RJ  
} '@1C$0tx  
} {uxTgX  

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/* 2`Ihrz6  
**TestMethod.java l!:L<B  
*/ uW4.Q_O!H  
package NetFox; ?>
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),2|TlQ  
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public class TestMethod { #Fkp6`Q$x  
|{MXDx  
BC#O.93`  
public TestMethod() 27MwZz  
{ ///xx/weblogic60b2_win.exe Z7k ku:9  
try{ { PS0.UZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); DXZZZ[#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); RL*b47,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); < Yc)F.:  
fileFetch.start(); r(rT.
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} n*9nzx#q  
catch(Exception e){e.printStackTrace ();} AB<%GzW0(  
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} |O;vWn'U2  
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public static void main(String[] args) 2s}G6'xE]P  
{ x+v&3YF
 
new TestMethod(); b"Jr_24t3v  
} bk]g}s  
} fZQ2<*)pqO  
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