http断点续传简单实现（java)

/* ?^hC|IR$  
**SiteFileFetch.java bvoR?D\-"  
*/ x
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package NetFox; #pZ3xa3R  
import java.io.*; !`u)&.t
7  
import java.net.*; 6l4l74  
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public class SiteFileFetch extends Thread { 7-^d4P+|g  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 0@ -LV:jU  
long[] nStartPos; //开始位置 ` p)#!  
long[] nEndPos; //结束位置 k,?k37%T]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _jtBU  
long nFileLength; //文件长度 Mqq7;w@(J  
boolean bFirst = true; //是否第一次取文件 OlP#|x*  
boolean bStop = false; //停止标志 }} IvZG&  
File tmpFile; //文件下载的临时信息 Nz m 7E]  
DataOutputStream output; //输出到文件的输出流 mGIS[_dcs  
PKP(:3|  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） xd*kNY  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]8RcZn  
{ {h
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siteInfoBean = bean; 1&dWt_\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); m^wYRA.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qwN-VCj  
if(tmpFile.exists ()) oOuWgr]0  
{ |2mEowAd  
bFirst = false; BM3nZ<%3  
read_nPos(); !Ed';yfz\(  
} kWgxswl7H  
else [j5L}e!T  
{ k@[Bx>  
nStartPos = new long[bean.getNSplitter()]; :wIbKs.r  
nEndPos = new long[bean.getNSplitter()]; mF "ctxE  
} ;&iQNXL  
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} 6%)dsTAB  

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public void run() "]sr4Jg=  
{ IkD\YPL;  
//获得文件长度 .7oz  
//分割文件 [z?<'Tj  
//实例FileSplitterFetch BsxQW`>^y  
//启动FileSplitterFetch线程 f;QWlh"9  
//等待子线程返回 NbSwn}e_  
try{ =x=#Etj|  
if(bFirst) 'E6)6N  
{ myH#.$=A  
nFileLength = getFileSize(); !.9NJ2'8  
if(nFileLength == -1) L='GsjF0}  
{ KX{S8_  
System.err.println("File Length is not known!"); &7;W=uF  
} w* v%S  
else if(nFileLength == -2) NJ3b Oq  
{ QH+Oi&xH  
System.err.println("File is not access!"); Pj^6.f+  
} a6[bF  
else 'y@0P5[se  
{ oM J5;  
for(int i=0;i<nStartPos.length;i++) g,\<fY+4  
{ xmbkn}@A  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |ONkRxr@!  
} k5|h8%h8  
for(int i=0;i<nEndPos.length-1;i++) ] OR]  
{ )wmXicURC  
nEndPos = nStartPos[i+1]; XmLHZ,/  
} )abo5   
nEndPos[nEndPos.length-1] = nFileLength; 7,Nd[ oL*7  
} wF}/7b54  
} y;uk|#qnPS  
JWC{"6  
!YCYmxw#  
//启动子线程 L[D}pL=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ZVViu4]?y  
for(int i=0;i<nStartPos.length;i++) ^*RmT  
{ q_JES4ofx  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), evq*&.6\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), j`(o\Fd )  
nStartPos,nEndPos,i); Nn+le
M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V*LpO8=  
fileSplitterFetch.start(); rT <=`9^{  
} }]kzj0m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {l![{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); H>k=V<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !DXKn\aQf  
nEndPos = " + nFileLength); D}Z].c@E  
// fileSplitterFetch[nPos.length-1].start(); dYW19$W n  
qHklu2_%  
I@e{>}  
//等待子线程结束 [/6IEt3}B  
//int count = 0; nx84l7<  
//是否结束while循环 >tYptRP  
boolean breakWhile = false; A6= Um%T  
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PO1sVP.S  
while(!bStop) 8nW#Q<s  
{ 1Sr@$+VGO  
write_nPos(); LsoP >vJG  
Utility.sleep(500); u<:
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breakWhile = true; "4zTP!Ow  
}"E?#&^  
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for(int i=0;i<nStartPos.length;i++) P'
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{ 7C F
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if(!fileSplitterFetch.bDownOver) ?FxxH*>"  
{ M5CFW >T  
breakWhile = false; (ybKACx  
break; 5l}v  
} PohG y  
} ?=$a6o  
if(breakWhile) ,_D`0B6o  
break; %TP0i#J  
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//count++; 8
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//if(count>4) zvL;.U  
// siteStop(); ]`b/_LJN$F  
} M1-n  
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System.err.println("文件下载结束！"); mY+Jju1  
} P?\IlziCB  
catch(Exception e){e.printStackTrace ();} q{nNWvL  
} /q0[T{Wz$  
M|w;7P}  
]%!:'#  
//获得文件长度 M| :wC  
public long getFileSize() _Y?p =;  
{ nn5tOV}QE  
int nFileLength = -1; eF823cH2x_  
try{ *0^!%Y'/4  
URL url = new URL(siteInfoBean.getSSiteURL()); T8bk\\Od  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /PafIq  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZBUEg7c  
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int responseCode=httpConnection.getResponseCode(); w^6rgCl  
if(responseCode>=400) `A_CLVE  
{ GWsvN&nr  
processErrorCode(responseCode);  ?%Hj,b  
return -2; //-2 represent access is error qcSlqWDk  
} R?Vs8?  
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{N42z0c  
String sHeader; &`Oj<UyJY  
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for(int i=1;;i++) gdPv,p19L  
{ R*|y:T,H  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); q$L=G  
//Utility.log(in.readLine()); pnl7a$z  
sHeader=httpConnection.getHeaderFieldKey(i); Uus%1hC%a  
if(sHeader!=null) ?%-VSL>$w=  
{ Up*1j:_O  
if(sHeader.equals("Content-Length")) ND $m|V-C  
{ I|8'#Q
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^yL6A1  
break; '#LbIv4  
} R/Y9t8kk  
} n;+CV~  
else R9@Dd  
break; E%8Op{zv_  
} v'na{"  
} $a.fQ<,\X  
catch(IOException e){e.printStackTrace ();} k<(G)7'gm  
catch(Exception e){e.printStackTrace ();} HI&N&a9C  
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Utility.log(nFileLength); =;Ap+}  
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return nFileLength; v<CZ.-r\j  
} &B?TX.  
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//保存下载信息（文件指针位置） {,xI|u2R  
private void write_nPos() utOATjB.z  
{ @{/GdB,}  
try{ `s1>7XWf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @pq2Z^SQH  
output.writeInt(nStartPos.length); $1lI6 = ,  
for(int i=0;i<nStartPos.length;i++) mWEaUi)Zz  
{ a4{~.Mp  
// output.writeLong(nPos); sT8(f=^)8F  
output.writeLong(fileSplitterFetch.nStartPos); T6mbGE*IeE  
output.writeLong(fileSplitterFetch.nEndPos);  ja!K2^  
} oE/g)m%  
output.close(); <5@VFRjc  
} 8G3CQ]G  
catch(IOException e){e.printStackTrace ();} W;L<zFFbU)  
catch(Exception e){e.printStackTrace ();} \"k[y+O],4  
}
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//读取保存的下载信息（文件指针位置） 76 nrDE  
private void read_nPos() \EI<1B  
{ J34/rL/s  
try{ 3QSA|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,j
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int nCount = input.readInt(); 3T1t !q4/5  
nStartPos = new long[nCount]; m{#?fR=9  
nEndPos = new long[nCount]; ;|yd}q=p  
for(int i=0;i<nStartPos.length;i++) X;:qnnO  
{ :)JIKP%$\)  
nStartPos = input.readLong(); C?dQ QB$  
nEndPos = input.readLong(); Odn`q=  
} )T0%<(J  
input.close(); \iL{q^Im  
} py|ORVN(Z  
catch(IOException e){e.printStackTrace ();} z3Id8G&>  
catch(Exception e){e.printStackTrace ();} =#=<%HPT  
} pzr\<U`  
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)}!Z^ND*  
private void processErrorCode(int nErrorCode) oz8z%*9(  
{ #Sg< 9xsW  
System.err.println("Error Code : " + nErrorCode); [pY1\$,  
} dMd2a4  
b6(LoN.  
h95a61a,Vy  
//停止文件下载 W0-KFo.'  
public void siteStop() E^s<5BC;  
{ Kx4_`;>  
bStop = true; ,]Gi942  
for(int i=0;i<nStartPos.length;i++) };{Qx  
fileSplitterFetch.splitterStop(); CU`yi.)T{  
]9A@iA  
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} vQH6CB"  
} C\`*_t  
//负责部分文件的抓取 |(eRv?Qy@  
**FileSplitterFetch.java simD<&p  
*/ !&(^R<-id  
package NetFox; !#[B#DZc(  
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1 lZRi-P  
import java.io.*; [LF<aR5  
import java.net.*; ^QG;:.3v  
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public class FileSplitterFetch extends Thread { kO3N.t@n  
(_0r'{`  
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String sURL; //File URL q 3nF\Me0  
long nStartPos; //File Snippet Start Position l/i7<q  
long nEndPos; //File Snippet End Position x*#9\*@EI  
int nThreadID; //Thread's ID N\{{:<Cp\  
boolean bDownOver = false; //Downing is over c3__=$)'kP  
boolean bStop = false; //Stop identical zk++#rB  
FileAccessI fileAccessI = null; //File Access interface Hd_W5R  
 j1~'[  
1CmjEAv%/  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )JsmzGC0  
{ "/kTEp  
this.sURL = sURL; w}rsboU  
this.nStartPos = nStart; E+"m@63  
this.nEndPos = nEnd; vuoD~=z  
nThreadID = id; )`,Y^`F2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [bh8Nj\E  
} /^\UB fE  
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public void run() e.'6q ($3  
{ U][\|8i  
while(nStartPos < nEndPos && !bStop) MO-7yp:K  
{ }UzRFIcv  
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try{ WlHK  
URL url = new URL(sURL); Wi2Tg^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); > }fw7X  
httpConnection.setRequestProperty("User-Agent","NetFox"); Bm$(4  
String sProperty = "bytes="+nStartPos+"-"; y!u=]BE  
httpConnection.setRequestProperty("RANGE",sProperty); *LOUf7`  
Utility.log(sProperty); 1+ib(MJ<:#  
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InputStream input = httpConnection.getInputStream(); AD>X'J u8  
//logResponseHead(httpConnection); zI{~;`tzN  
[4 y7tjar^  
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byte[] b = new byte[1024]; ]L/AW  
int nRead; U9(p ^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ! _p
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{ vw)lD9-"  
nStartPos += fileAccessI.write(b,0,nRead);
k];NTALOG  
//if(nThreadID == 1) |w+N(wcJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q4h6K7  
} @<ILF69b  
?F"mZu  
BN%;AQV  
Utility.log("Thread " + nThreadID + " is over!"); [Ol~}@gV  
bDownOver = true; ,GUOq!z  
//nPos = fileAccessI.write (b,0,nRead); /Bs42uJ3  
} N9cCfB\`  
catch(Exception e){e.printStackTrace ();} U["-`:>jfp  
} DkJ "#8Yl=  
} JU3to_Io  
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//打印回应的头信息 11YpC;[o  
public void logResponseHead(HttpURLConnection con) eufGU)M  
{ 6%a:^
f]  
for(int i=1;;i++) TGH"OXV*@  
{ gZ@z}CIw'  
String header=con.getHeaderFieldKey(i); N%Uk/ c'  
if(header!=null) n^iq?u  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6-Id{mx  
Utility.log(header+" : "+con.getHeaderField(header)); k9m9IE"9=$  
else Xj5oHHwn  
break; %$[#/H7=W  
} .D{He9  
} Pr'Ij  
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2(
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public void splitterStop() ?k$'po*Eq  
{ i`^[_  
bStop = true; YR-G
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} hxZL/_n'  
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} 2(AuhZ>  
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+SNjU"x  
/* g\]~H%2 ,  
**FileAccess.java Yfr4<;%  
*//文件访问(定位，写) b_Dd$NC  
package NetFox; e+<'=_x {  
import java.io.*; +3[8EM#g  
CB^.N>'  
fM`.v+  
public class FileAccessI implements Serializable{ P09f  
2rxz<ck(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  &4{!5r  
RandomAccessFile oSavedFile; ~@$RX:p  
long nPos; K$KVm^`  
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public FileAccessI() throws IOException W1_.wN$,5  
{ /|m0)H.>  
this("",0); X]}:WGFM  
} &embAqW:  
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public FileAccessI(String sName,long nPos) throws IOException C`=YGyj=TL  
{ G|YNShK4=9  
oSavedFile = new RandomAccessFile(sName,"rw"); #z+?t  
this.nPos = nPos; {zalfw{+  
oSavedFile.seek(nPos); ' eh }t  
} a"&cm'\lL  
+c$:#9$ |  
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public synchronized int write(byte[] b,int nStart,int nLen) e2yCWolmTS  
{ :gn&wi  
int n = -1; {H*  
try{ :$*@S=8O  
oSavedFile.write(b,nStart,nLen); NfWL3"&X  
n = nLen; bTt1y
O  
} F*T$n"^  
catch(IOException e) =~>g--^U  
{ !/e*v>3u&  
e.printStackTrace (); [1nUq!uTm  
} Mc&Fj1h5  
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D  
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return n; ?a-5^{{  
} k [LV^oEg  
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} ~dk97Z8  
]h,iyWSs  
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/* !;;7:!)P  
**SiteInfoBean.java 'Y.6sB  
*/ aS``fE;O  
package NetFox; |`xM45  
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public class SiteInfoBean { R?IRE91 :  
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private String sSiteURL; //Site's URL b:cy(6G(  
private String sFilePath; //Saved File's Path <_c8F!K)T  
private String sFileName; //Saved File's Name bjo}95  
private int nSplitter; //Count of Splited Downloading File 9s1^hW2%Q  
7Ie=(x8):  
LmytO$?2(  
public SiteInfoBean() fm L8n<1  
{//nSplitter的缺省值为5 d8iq9AP\o  
//default value of nSplitter is 5 6bPl(.(3  
this("","","",5); 0U~*uDU  
} Mi;Pv*  
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B$n1k45  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) SgYMPBh  
{ }'*6 A  
sSiteURL= sURL; ujzfy  
sFilePath = sPath; :yRv:`r3Lt  
sFileName = sName; 2$ &B@\WY  
this.nSplitter = nSpiltter; QIg'js$W  
C T\@>!'f  
7WwE] ^M  
} b;%t*?t  
lh[?`+A  
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public String getSSiteURL() Y2;2Exp^  
{ T];dFv-GT  
return sSiteURL; uuxVVgWp{  
} qXhdU/ =  
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~>HzAo9e  
public void setSSiteURL(String value) [Ky3WppR  
{ x FWh
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sSiteURL = value; >lfuo  
} lj Ud
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l&}}Io$?@  
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public String getSFilePath() b]f
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{
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return sFilePath; v+I-*,R  
} Io|D
u  
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public void setSFilePath(String value) IrMB=pWo  
{ +<
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sFilePath = value; 8XG';K_  
} .r2*tB).  
9Msy=qvYG  
z~ywFk}KGd  
public String getSFileName() R|v'+bv  
{ H]pI$t3~  
return sFileName; yIrJaS-  
} XbqMWQN*  
]8}51y8  
o<G#%9j  
public void setSFileName(String value) "VZXi_P  
{ \+l*ZNYM3  
sFileName = value; Yj#tF}nPC  
} NcP/W>lN  
jj1\
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'3Lu_]I-  
public int getNSplitter() OQ7 `n<I<)  
{ m3TR}=n  
return nSplitter; z9*e%$+
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} :nQlS  
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public void setNSplitter(int nCount) o6d x\  
{ t*=[RS*  
nSplitter = nCount; ATl?./Tu  
} _$ivN!k  
} xH xTL>,?  
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'gvR?[!t  
/* X!p`|i  
**Utility.java G$>
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*/ XTo7fbW*  
package NetFox;  }:Gs ,  
sVK?sBs]  
o`,~#P|  
public class Utility { Fq@o_bI  
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Q-n8~Ey1a  
public Utility() mAtqF %V  
{ EU%,tp   
^>?=L\[  
!:^q_q4  
} t/\
 
?B1Zfu0  
//线程睡眠 pA6KiY&  
public static void sleep(int nSecond) !g9k9 l  
{ V}Y*Yv  
try{ E4L?4>V@\  
Thread.sleep(nSecond); ]7O<|8n!d  
} W&IG,7tr  
catch(Exception e) Wn'a'  
{ {aUnOyX_  
e.printStackTrace (); =/!lK&  
} y%SxQA+\  
} G{3|d/;Bt  
O\ZC$XF  
//日志 G aV&y  
public static void log(String sMsg) IWQ0I&tzdx  
{ k*\Bl4g  
System.err.println(sMsg); (4T0U5jgT  
} 5e/YEDP  
x,!Dd  
1)56ec<c  
public static void log(int sMsg) sD:o 2(G*  
{ @ph!3<(In,  
System.err.println(sMsg); kh5a>OX  
} #$I@V4O;#  
} Uj):}xgi'  
l1)~WqhE}  
U!aM63F3  
/* V4n~Z+k  
**TestMethod.java .eR1\IAm  
*/  bDkZU  
package NetFox; iT>u&0B-  
Aqmpo3P[+  
hMa;\k  
public class TestMethod { Y~WdN<g  
%_ibe  
jYHnJ}<  
public TestMethod() *nCA6i  
{ ///xx/weblogic60b2_win.exe QB*,+u4  
try{ i6WH^IQM  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 68Fl/   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j uA@"SG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0%ul6LvM  
fileFetch.start(); <RY =y?%z  
} ; oyV8P$  
catch(Exception e){e.printStackTrace ();} eDJnzh83  
X0G,tl  
"mK`3</G  
} N1a]y/  
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2:*15RH3  
public static void main(String[] args) m,k0 h%  
{ IZ=Z=k{  
new TestMethod(); ipu!{kJ  
} S&_03  
} 'D+xs}\  
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