http断点续传简单实现（java)

/* &TC  
**SiteFileFetch.java EHo"y.ODg  
*/ Qj3UO]>  
package NetFox; 17};I7  
import java.io.*; G_dia6  
import java.net.*; eZ ]6Q  
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public class SiteFileFetch extends Thread { I<[(hPQ
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2.; OHQTE  
long[] nStartPos; //开始位置 .l#Pmd!  
long[] nEndPos; //结束位置 |mci-ZT  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .:<c[EJ b  
long nFileLength; //文件长度 Zsf<)Vx  
boolean bFirst = true; //是否第一次取文件 O\G%rp L$w  
boolean bStop = false; //停止标志 D0"+E*   
File tmpFile; //文件下载的临时信息 CsuSg*#X+  
DataOutputStream output; //输出到文件的输出流 H<1C5-  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @^;\(If2  
public SiteFileFetch(SiteInfoBean bean) throws IOException uOougSBV,  
{ Q[~O`Lz  
siteInfoBean = bean; p&ow\AO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uP+ j_is
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `o:)PTQNg  
if(tmpFile.exists ())  uiiA)j*!  
{ "I_T  
bFirst = false; #uey1I@"9  
read_nPos(); &,KxtlR![  
} urtcSq&H'  
else CWC*bkd5a  
{ >8>.o[Q&  
nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()]; R@"N{ [9  
} ]~a!O  
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} iB]kn(2C  
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public void run() y& Dd  
{ 8mCr6$|
%  
//获得文件长度 %*jpQOw  
//分割文件 MTLcLmdO  
//实例FileSplitterFetch v,>q]! |a  
//启动FileSplitterFetch线程 2<B+ID3qv  
//等待子线程返回 P *%bG 4  
try{ YjdH7.js  
if(bFirst) 1noFXzeU3  
{ `5!7Il  
nFileLength = getFileSize(); S3 x:]E:   
if(nFileLength == -1) ?*4]LuK6  
{ LO` (V  
System.err.println("File Length is not known!"); 4["}U1sG  
} 0udE\/4!^  
else if(nFileLength == -2) -3w? y  
{ AY! zXJ_$  
System.err.println("File is not access!"); =}Cb?C[;  
} }8r+&e  
else TFM}
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{  *riGi  
for(int i=0;i<nStartPos.length;i++) RmzK?muk  
{ />f`X+d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Nwu#,f=X  
} nLQ X?:  
for(int i=0;i<nEndPos.length-1;i++) ^[id
8  
{ 4|XE f,  
nEndPos = nStartPos[i+1]; )<3WVvB  
} 3>S.wyMR4  
nEndPos[nEndPos.length-1] = nFileLength; H;$w^Tr  
} 5[Q44$a{  
} :uI}"Bp  
N%Lh_2EzqV  
KDn`XCnk,  
//启动子线程 Sfvi|kZX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *b7v)d#  
for(int i=0;i<nStartPos.length;i++) hcN$p2-  
{ _L: /2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jj.yB#T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >,~JQ%1  
nStartPos,nEndPos,i); xJO[pT v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5Impv3qaZ  
fileSplitterFetch.start(); u |f h!-  
} C[x!Lf8'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qv,|7yw{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); OZISh?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b
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nEndPos = " + nFileLength); w5&UG/z%l  
// fileSplitterFetch[nPos.length-1].start(); 4!monaB"e  
6 #QS5  
?=PQQx2_*u  
//等待子线程结束 YemOP9  
//int count = 0; 0~FX!1;  
//是否结束while循环 rj:$'m7  
boolean breakWhile = false; $jw!DrE  
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mBnC]$<R  
while(!bStop) uF<F4m;  
{ @V<tg"(c  
write_nPos(); D|+H!f{k  
Utility.sleep(500); pf2$%lE  
breakWhile = true; E^|b3G6T  
b[u_r,b  
=-vk}O0C  
for(int i=0;i<nStartPos.length;i++) 'x!q*|zF2  
{ y2<g
96  
if(!fileSplitterFetch.bDownOver) b%v1]a[  
{ Yq2mVo  
breakWhile = false; XKR?vr7A2  
break; jh=:QP/  
} }K&K{ 9}  
} 6*]
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if(breakWhile) $?'z%a{  
break; 778L[wYe  
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//count++; 9@:&E  
//if(count>4) k:d'aP3  
// siteStop(); -gC=%0sp\  
} m=opY~&h  
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System.err.println("文件下载结束！"); .j;My%)?p  
} us5`?XeX]  
catch(Exception e){e.printStackTrace ();} nJLr]`_  
} al"1T-  
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//获得文件长度 ,a?em'=  
public long getFileSize() WQ6E8t)  
{ WM>9sJf  
int nFileLength = -1; d;'@4NX5+  
try{ w0 "h,{  
URL url = new URL(siteInfoBean.getSSiteURL()); m&; t;&#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `@`Q"J  
httpConnection.setRequestProperty("User-Agent","NetFox"); |7f}icXKur  
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6o{anHBB  
int responseCode=httpConnection.getResponseCode(); e"2 wXd_}  
if(responseCode>=400) JQ.ZAhv  
{ nYE_WXY3V  
processErrorCode(responseCode); 8LiRZ"  
return -2; //-2 represent access is error 43 |zjE  
}  snN1  

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String sHeader; D* Vr)J  
&<v#^2S3  
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for(int i=1;;i++) YF."D%?  
{ K=!J=R;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G\Sd!'?p  
//Utility.log(in.readLine()); w8@Ok_fj  
sHeader=httpConnection.getHeaderFieldKey(i); wV U(Du  
if(sHeader!=null) g fO.Ky6  
{ U); ,Opr  
if(sHeader.equals("Content-Length")) /e\} qq  
{ 3`="4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); g]d@X_ &D  
break; I.\u2B/?  
} =0m[  
} o_={xrmIA  
else i?mDR$X:  
break; 6!+"7r6  
} nY(jN D  
} '6K WobXm  
catch(IOException e){e.printStackTrace ();} }*?e w  
catch(Exception e){e.printStackTrace ();} $`]<4I9d  
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Utility.log(nFileLength); ~L4"t_-  
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return nFileLength; Url8Z\;aM  
}
}3N8EmS  
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//保存下载信息（文件指针位置） ~;U!?  
private void write_nPos() &_!BMzp4  
{ *Z{W,8h*s  
try{ o F@{&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5#:tL&q  
output.writeInt(nStartPos.length); ( 6r9y3'  
for(int i=0;i<nStartPos.length;i++) sPbtv[bC  
{ rWa7"<`p  
// output.writeLong(nPos); m*["  
output.writeLong(fileSplitterFetch.nStartPos); `ORDN|s6  
output.writeLong(fileSplitterFetch.nEndPos); (4b&}46  
} GDOaZi  
output.close(); %_A1WC  
} !fz`O>-mZ  
catch(IOException e){e.printStackTrace ();} oYOf<J  
catch(Exception e){e.printStackTrace ();} %s<7|,  
} E%+V\ W%  
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//读取保存的下载信息（文件指针位置） pk"JcUzR  
private void read_nPos() +F 5Dc  
{ 2]Y (<PC  
try{ ,j2qY'wi  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !%5{jO1  
int nCount = input.readInt(); 1w\Y._jK  
nStartPos = new long[nCount]; KF
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nEndPos = new long[nCount]; QmgwIz_  
for(int i=0;i<nStartPos.length;i++) <2,@rYe/  
{ 93YD\R+q  
nStartPos = input.readLong(); orTTjV]_m  
nEndPos = input.readLong(); -6)ywq^{z  
} YM#XV*P0 q  
input.close(); '8%aq8  
} ~ocd4,d=  
catch(IOException e){e.printStackTrace ();} OE:t!66
 
catch(Exception e){e.printStackTrace ();} [IW@mn>  
} m<OxO\Mpf  
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private void processErrorCode(int nErrorCode) fpoH7Jd V  
{ J-u,6c  
System.err.println("Error Code : " + nErrorCode); zJ &qR  
} +R*4`F:QJQ  
@W^g(I(w  
/mr&Y}7T
 
//停止文件下载 ?k"KZxpT  
public void siteStop() BH*vsxe  
{ *TMg.  
bStop = true; v[lytX4)  
for(int i=0;i<nStartPos.length;i++) BNzL+"W  
fileSplitterFetch.splitterStop(); n1$##=wK]  
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} \ iP[iE=  
} _NZ) n)  
//负责部分文件的抓取 s"a*S\a;b  
**FileSplitterFetch.java P,wFib^1  
*/ eKu&_q  
package NetFox; iUl{_vb  
#0^QUOp  
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import java.io.*; YQ?|Vb U  
import java.net.*; ;tKL/eI  
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public class FileSplitterFetch extends Thread { (EohxLl!p  
vTB*J,6.  
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String sURL; //File URL H) (K  
long nStartPos; //File Snippet Start Position bfa5X<8  
long nEndPos; //File Snippet End Position S - 7JDE>  
int nThreadID; //Thread's ID DJ<e=F!  
boolean bDownOver = false; //Downing is over E}a3.6)p  
boolean bStop = false; //Stop identical `SIJszqc  
FileAccessI fileAccessI = null; //File Access interface a(}jn|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =z@'vu$Fh  
{ ";>D0h^D  
this.sURL = sURL; t_j.@|/FZ  
this.nStartPos = nStart; ;$0za]x  
this.nEndPos = nEnd; DR=>la}!  
nThreadID = id; 89 SsSb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Pu*st=KGB  
} h[B Ft{x  

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+)7NWR\  
public void run() {0QA+[Yd&!  
{ WG^D$L
:  
while(nStartPos < nEndPos && !bStop) Y ,}p  
{ yp :yS  
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fSun{?{  
try{ (@&|  
URL url = new URL(sURL); WxXVL"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VD=$:

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httpConnection.setRequestProperty("User-Agent","NetFox"); 6XX5K@  
String sProperty = "bytes="+nStartPos+"-"; [KjQW/sb'  
httpConnection.setRequestProperty("RANGE",sProperty); +_`F@^R_  
Utility.log(sProperty); Th!S?{v  
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InputStream input = httpConnection.getInputStream(); ltD:w{PO]  
//logResponseHead(httpConnection); -7+Fb^"L  
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byte[] b = new byte[1024]; Z:n33xh=<  
int nRead; .{8lG^0U<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =,?@p{g}  
{ ZW\h,8%  
nStartPos += fileAccessI.write(b,0,nRead); bxyU[`  
//if(nThreadID == 1) JP@UvDE|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mKn[>M1  
} 0,/[r/=jT  
{'X"9@  
1r.q]^Pq~  
Utility.log("Thread " + nThreadID + " is over!"); >>!+Ri\@  
bDownOver = true; O&X-)g=  
//nPos = fileAccessI.write (b,0,nRead); n09|Jzv9  
} NtT)Wl  
catch(Exception e){e.printStackTrace ();}
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} U'#{v7u  
} Xi|v!^IT  
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//打印回应的头信息 :Mt/6}
 
public void logResponseHead(HttpURLConnection con) 1yE~#KpH  
{ |a"(Ds2U  
for(int i=1;;i++) -,+JE0[  
{ d&U;rMEv  
String header=con.getHeaderFieldKey(i); kW(8i}bg  
if(header!=null) =
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); )<Yy.Z_:DC  
Utility.log(header+" : "+con.getHeaderField(header)); j
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else .^v7LF]Q  
break; \LS%bO,Y|  
} as\V, {<  
} ~ 01]VA  
%? iE3j!q  
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public void splitterStop() XBeHyQp  
{ mV'd9(s?  
bStop = true; km3-Hp1  
} xbmOch}j6  
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} p4el9O&-tV  
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/* Ao]F
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**FileAccess.java 0um
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*//文件访问(定位，写) "5YsBih  
package NetFox; \(A>~D8Fo  
import java.io.*; ?s_q
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Lv5AtZl}  
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public class FileAccessI implements Serializable{ X'3F79`  
>%W"u`Q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 I/@Xr  
RandomAccessFile oSavedFile; RnTPU`  
long nPos; O=+C Kx@  
*]H ./a:1  
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public FileAccessI() throws IOException qI'a|p4fn?  
{ '<@PgO~  
this("",0); w!xSYh')  
} QR,i b  
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public FileAccessI(String sName,long nPos) throws IOException u{_T,k<!  
{ Y- w5S|!  
oSavedFile = new RandomAccessFile(sName,"rw"); 2Nj0 Hqjq  
this.nPos = nPos; GN{.R7  
oSavedFile.seek(nPos); *.K}`89T  
} ~E`l4'g?  
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public synchronized int write(byte[] b,int nStart,int nLen) 2[:`w),.  
{ h<QXr'4+  
int n = -1; $B(B  
try{ MW&;{m?2(  
oSavedFile.write(b,nStart,nLen); ~o8$/%Oeb/  
n = nLen; ,v^it+Jc'  
} JY_' d,O  
catch(IOException e) U}{r.MryFG  
{ jbg@CA*=C  
e.printStackTrace (); 6D
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} eH6#'M4+\  
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return n; \C>I6{  
} *D9QwQ _|  
q= tDMK'h  
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} 9EH%[wfv  
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/* @ 8SYV}0H  
**SiteInfoBean.java LS \4y&J40  
*/ AFY;;_Xks  
package NetFox; M9iu#6P  
"? R$9i  
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public class SiteInfoBean { ~+|p.(I  
cy? EX~s4  
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private String sSiteURL; //Site's URL /]vg_&)=  
private String sFilePath; //Saved File's Path %i96@6O  
private String sFileName; //Saved File's Name |M+ !O93  
private int nSplitter; //Count of Splited Downloading File K~Xt`  
7.]xcJmt>'  
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public SiteInfoBean() rv\<Q-uQ8  
{//nSplitter的缺省值为5 <vPIC G)  
//default value of nSplitter is 5 [g%oo3`A  
this("","","",5); w1.KRe{M  
} 5jbd!t@L  
oinF<-(  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KBOxr5w  
{ 2'/ ip@  
sSiteURL= sURL; qUVV374N  
sFilePath = sPath; T}g;kppC  
sFileName = sName; _jr%s  
this.nSplitter = nSpiltter; nGg>lRL
  
;[*7UE+#7  
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} |KkVt]ZQe9  
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public String getSSiteURL() *V
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{ 8_:jPd!3  
return sSiteURL; z5Po,@W  
} !,I}2,1%k  
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dhV=;'   
public void setSSiteURL(String value) _I75[W!  
{ UoBu0Rx  
sSiteURL = value; F|Ou5WD  
} p>!`JU`{?  
;Qw>&2
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public String getSFilePath() *)"`v]  
{ qex.}[  
return sFilePath; "Z#&A  
} Vw+U?  
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public void setSFilePath(String value) ;K`qSX;;c(  
{ TqzkF7;k4  
sFilePath = value; rrmr#a  
} a2sN$k  
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public String getSFileName() V
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{ 5{j1<4zxR  
return sFileName; ,I[  
} 8/]5h%  
++5SofG@  
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public void setSFileName(String value) m+,a=sR  
{ ECQ>VeP  
sFileName = value; <Ms,0YKx  
} 3~"G27,  
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=Cu!  
public int getNSplitter() "Bn!<h}mg  
{ -Y;(yTtz  
return nSplitter; >e'6RZRLA  
} @G^ l`%  
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public void setNSplitter(int nCount) vz/.*u  
{ pWK7B`t  
nSplitter = nCount; epR7p^`7  
} v2/@Pu!kg  
} 1iig0l6\m  
#r>  
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/* a%V6RyT4qW  
**Utility.java y/Paq^Hd  
*/ P^T]Ubv"  
package NetFox; -n+=[M  
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public class Utility { NRgNh5/  
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public Utility() L;wzvz\+  
{ E.zY(#S  
Hq ]f$Q6:  
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} dXg.[|S*  
Wz;7 |UC  
//线程睡眠 -Uh3A\#(  
public static void sleep(int nSecond) ewvFUD'j  
{ T2Ms/1FH/@  
try{ {ZrIA+eH  
Thread.sleep(nSecond); zU}Ru&T9  
} PqKbG<}Y  
catch(Exception e) V*Ta[)E  
{ U\s.fIr  
e.printStackTrace (); F^fL  
} lhZXq!2p  
} >;:235'(M  
GHaD32  
//日志 XOe)tz L  
public static void log(String sMsg) ~M _@_  
{ a9}7K/Y=d  
System.err.println(sMsg); p.~hZ+ x_  
} I($0&Y\De  
*6IytWOX5  
8Qd*OO  
public static void log(int sMsg) o9*}>J<+RQ  
{ 6QO[!^lY  
System.err.println(sMsg); z10J8Ms'  
} 'I^3r~_  
} aQzx^%B1  
BE>^;`K  
td@I ;d2  
/* 3k3-Ts  
**TestMethod.java /Ps/m!  
*/ }Vjg>"  
package NetFox; @{n"/6t  
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RrA9@95+  
public class TestMethod { .z0NMmz0z  
+&bJhX  
rr~O6Db  
public TestMethod() L6<.>\^Z"  
{ ///xx/weblogic60b2_win.exe 40h  
try{ FabgJu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {8p<iY- %  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @$mh0K>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r9sq3z|%  
fileFetch.start(); N)CM^$(T|  
} 2 8>  
catch(Exception e){e.printStackTrace ();} uC$!|I  
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r`-=<@[  
} 5!-+5TJI  
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public static void main(String[] args) n4Xh}KtH  
{ $y{rM%6JU  
new TestMethod(); =^ZDP1h/}  
} IE]? WW5  
} <<WqL?8W  
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