http断点续传简单实现（java)

/* ;BjJ<?^{  
**SiteFileFetch.java 0]MI*s>&  
*/ Aj "SSX!L  
package NetFox; kYU!6t1  
import java.io.*; TTm  
import java.net.*; D0@d}N  
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public class SiteFileFetch extends Thread { O*-sSf   

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SiteInfoBean siteInfoBean = null; //文件信息Bean  cvO;xR  
long[] nStartPos; //开始位置 <G#z;]N  
long[] nEndPos; //结束位置 V|G
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 6uubkt  
long nFileLength; //文件长度 gfmaO]  
boolean bFirst = true; //是否第一次取文件 b@yFqgJ_  
boolean bStop = false; //停止标志 4!0nM|~  
File tmpFile; //文件下载的临时信息 q.69<Rs  
DataOutputStream output; //输出到文件的输出流 ?&se]\  
kq=tL@W`0}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ff<adl-  
public SiteFileFetch(SiteInfoBean bean) throws IOException O>sE~~g]?  
{ Ll'!aar,  
siteInfoBean = bean; _~_6qTv-d  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WDQw)EUl&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); iB
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if(tmpFile.exists ()) <]kifiN#  
{ ?8aPd"x  
bFirst = false; jG~UyzWH;  
read_nPos(); u(P;) E"1  
} rBovC  
else z{dn  
{ Q5pm^X._j  
nStartPos = new long[bean.getNSplitter()]; jN^09T49  
nEndPos = new long[bean.getNSplitter()]; ,Z p9,nf  
} :R9 DJh\  
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} E!v^j=h$u  
]#Q'~X W  
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public void run() Ax"I$6n>  
{ h2
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//获得文件长度 t4CI+fqy  
//分割文件 PbN"+qM  
//实例FileSplitterFetch 7z4u?>pne*  
//启动FileSplitterFetch线程 6N]V.;0_5  
//等待子线程返回 1[r;  
try{ x:WxEw>R  
if(bFirst) +jpC%o}C  
{ 1q(o3%   
nFileLength = getFileSize(); y6!Zt}m  
if(nFileLength == -1) 0&|,HK  
{ &+>)H$5  
System.err.println("File Length is not known!"); xtP=/B/  
} <6) w  
else if(nFileLength == -2) jt8% L[  
{ 8ncgTCH:  
System.err.println("File is not access!"); %l8nTcL_?  
} "7tEk<x  
else 7Vxe]s  
{ {|Pz9a-:  
for(int i=0;i<nStartPos.length;i++) fG\]&LFBU  
{ + s snCr  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +: oD?h  
} ljo^ 2  
for(int i=0;i<nEndPos.length-1;i++) sCF7K=a  
{ xr\wOQ*`  
nEndPos = nStartPos[i+1]; @YfCS8 eH  
} Cq,hzi-  
nEndPos[nEndPos.length-1] = nFileLength; ^>fjURR  
} 7,N>u8cTh  
} C5jR||  
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T c{]w?V  
//启动子线程 =2=n   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Q9 *N/2+  
for(int i=0;i<nStartPos.length;i++) :,^pLAt  
{ q$=EUB"C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >@o}l:*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #Ua+P(1q  
nStartPos,nEndPos,i); ,lly=OhKb  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %wp#vO-$  
fileSplitterFetch.start(); #815h,nP+  
} @|^2 +K/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \Ow-o0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); bUp ,vc*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?>p<!:E!r  
nEndPos = " + nFileLength); 2W=( {e)$  
// fileSplitterFetch[nPos.length-1].start(); VIxt;yE  
Sh_=dzM  
(]mh}=:KDg  
//等待子线程结束 *0,?QS-a  
//int count = 0; =Xc[EUi<;g  
//是否结束while循环 )2P4EEs[  
boolean breakWhile = false; 6QOdd6_d  
)A4WK+yD$z  
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while(!bStop) 7gV"pa
  
{ `[;b#.  
write_nPos(); <k^P>Irb3t  
Utility.sleep(500); $MmCh&V  
breakWhile = true; .qioEqK8!y  
%#Vn?zr|~  
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for(int i=0;i<nStartPos.length;i++) Q\~4J1  
{ [k9aY$baT^  
if(!fileSplitterFetch.bDownOver) $z+iB;x  
{ .FnO  
breakWhile = false; 1;l&ck-Gg/  
break; ZL`G<Mo;.  
} A2b C5lA  
} !t["pr\ ?  
if(breakWhile) h 
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break; O]n"aAu@  
qYW{$K  
}V3p <  
//count++; Qj? G KO  
//if(count>4) 4><b3r;T'  
// siteStop(); )CzWq}:  
} In0kP"  
6?0^U 9  
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System.err.println("文件下载结束！"); ~7!J/LHg  
} %3i/PIN  
catch(Exception e){e.printStackTrace ();} =De%]]>   
} g]V}azLr  
1@Bq-2OD4  
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//获得文件长度 ~4wbIE_rN  
public long getFileSize() ;C%D+"l1g  
{ hgE!)UE  
int nFileLength = -1; 1WPDMLuN  
try{ :XMw="u=  
URL url = new URL(siteInfoBean.getSSiteURL()); <v"C`cga  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wx&AY"J  
httpConnection.setRequestProperty("User-Agent","NetFox"); p1HU2APFP  
1V?}";T  
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int responseCode=httpConnection.getResponseCode(); 8 F'i5i  
if(responseCode>=400) Hi{c[;  
{ J! >HT'M  
processErrorCode(responseCode); )}?'1ciHI  
return -2; //-2 represent access is error ^6+P&MxM  
} MjG=6.J|`  
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RC8{QgaI  
String sHeader; 2|o6~m<pE  
Um\Nd#=:  
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for(int i=1;;i++) 0K,*FdA  
{ 0z."6r  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); JW&/l  
//Utility.log(in.readLine()); >.PLD} zE_  
sHeader=httpConnection.getHeaderFieldKey(i); Q/iaxY#  
if(sHeader!=null) mqk~Pno|<  
{ b^PYA_k-Xn  
if(sHeader.equals("Content-Length")) uj&^W[s  
{ A$W,#`E  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !a3cEzs3  
break; ]}F_nc2L  
} Tn/ 3`j {  
} K3?7Hndf2  
else QQ97BP7W  
break; > K,Q`sS  
} E'$r#k:o  
} #HB]qa  
catch(IOException e){e.printStackTrace ();} !l_1r$  
catch(Exception e){e.printStackTrace ();} A75IG4]  
Y-n*K'  
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Utility.log(nFileLength); %Md;=,a:6  
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return nFileLength; CIQo2~G  
} Hw<t>z k  
br<,?  
?YX2CJ6N  
//保存下载信息（文件指针位置） g!D?Yj
4  
private void write_nPos() Bfaj4i;_  
{ zp"sM z]  
try{ kwK<?\D  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %|o4 U0c  
output.writeInt(nStartPos.length); *gu~7&yoP  
for(int i=0;i<nStartPos.length;i++) L]kSj$A  
{ `#2}[D   
// output.writeLong(nPos);  F[115/  
output.writeLong(fileSplitterFetch.nStartPos); ;hmy7M1%  
output.writeLong(fileSplitterFetch.nEndPos); fT/;TK>z>  
} 2M= gpy  
output.close(); _7]*
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} j*g5f  
catch(IOException e){e.printStackTrace ();} WU{G_Fqaz  
catch(Exception e){e.printStackTrace ();} sBq @W4  
} qJVW :$1q  
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F^&_O*"  
//读取保存的下载信息（文件指针位置） .!,T>:R  
private void read_nPos() #=5/D@  
{ \Q?r+VZ  
try{ ~0|Hw.OK  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,#UaWq@7  
int nCount = input.readInt(); Tw`^  
nStartPos = new long[nCount]; JpxJZJ  
nEndPos = new long[nCount];  hPx=3L$  
for(int i=0;i<nStartPos.length;i++) : UD<1fh  
{ sk$MJSE ~  
nStartPos = input.readLong(); yFshV\  
nEndPos = input.readLong(); 1'R]An BV  
} P$N\o@  
input.close(); RXb+"/  
} %IW=[D6Tg  
catch(IOException e){e.printStackTrace ();} &voyEvX/S  
catch(Exception e){e.printStackTrace ();} wvcG <sj  
} ; @-7'%(C  
2ME3=C  
#)hM]=,e  
private void processErrorCode(int nErrorCode) |JSj<~1ki  
{ L/"XIMI*Xg  
System.err.println("Error Code : " + nErrorCode); ;a XcGa  
} >"{3lDyq-  
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!CTchk<{(  
//停止文件下载 I/<aY*R4  
public void siteStop() w8kp6_i'  
{ 5K;jW  
bStop = true; |jk"; h  
for(int i=0;i<nStartPos.length;i++) Aj;Z &  
fileSplitterFetch.splitterStop(); 7pMrYIP  
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} 0j
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} ~M3`mO+^U  
//负责部分文件的抓取 #O/ihRoaO  
**FileSplitterFetch.java -{>JF  
*/ *@S:f"i  
package NetFox; "e0$/WQ6J  
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import java.io.*; /=*h\8c~  
import java.net.*; t)=u}t$  
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public class FileSplitterFetch extends Thread { !0CC&8C`  
#pErGz'{  
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String sURL; //File URL 0+}42g|_Z  
long nStartPos; //File Snippet Start Position Cz-eiPlq  
long nEndPos; //File Snippet End Position x?9rT 0D  
int nThreadID; //Thread's ID <3m_} =\  
boolean bDownOver = false; //Downing is over M^AwOR7<  
boolean bStop = false; //Stop identical 3E$M{l  
FileAccessI fileAccessI = null; //File Access interface %(MaH  
6.ASLH3#  
casva;  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException PB_+:S^8  
{ B<u6Z!Pp2  
this.sURL = sURL; *8M0h9S$  
this.nStartPos = nStart; <kN4@bd;  
this.nEndPos = nEnd; / Of*II&  
nThreadID = id; [`BMi-WQ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +)h*)  
} __fa,kK{?  
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public void run() :3pJGMv(  
{ 5 >S#ew  
while(nStartPos < nEndPos && !bStop) =&;orP  
{ ]B/Gz  
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try{ (/UW}$] h  
URL url = new URL(sURL); Hm!ffqO_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :hr% 6K7  
httpConnection.setRequestProperty("User-Agent","NetFox"); dlmF?N|EC  
String sProperty = "bytes="+nStartPos+"-"; y
{ %2Q)  
httpConnection.setRequestProperty("RANGE",sProperty); u9ObFm$7  
Utility.log(sProperty); 6c,]N@,Zw  
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InputStream input = httpConnection.getInputStream(); {4J:t_<nKO  
//logResponseHead(httpConnection); zP$0B!9  
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byte[] b = new byte[1024]; @E;'Ffo  
int nRead; 
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gBp,p\ Xc  
{ D[32t0  
nStartPos += fileAccessI.write(b,0,nRead); |ZZl3l=]  
//if(nThreadID == 1) _&)^a)Nu  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kH/u]+_  
} W/DSj :  
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Utility.log("Thread " + nThreadID + " is over!"); `2
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bDownOver = true; h\| ~Q.kG  
//nPos = fileAccessI.write (b,0,nRead); ^YG'p?r.s  
} (8T36pt~  
catch(Exception e){e.printStackTrace ();} `Sgj!/!F  
} 3D32'KO_"  
} NbgK#;  
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kZ7\zbN>  
//打印回应的头信息 $;7,
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public void logResponseHead(HttpURLConnection con) HHVCw7r0  
{ )r2$!(NQ  
for(int i=1;;i++) 8T<LNC  
{ ;w>Dqem  
String header=con.getHeaderFieldKey(i); vP6NIcWC3  
if(header!=null) t|-TG\Q X  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _3@[S F  
Utility.log(header+" : "+con.getHeaderField(header)); KYa}k0tVAp  
else Q+@/.qJ  
break; s8BfOl-  
} ykK21P,v  
} NZT2ni4  
<L'!EcHm%]  
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public void splitterStop() eb1WTK@  
{ ?.Iau/  
bStop = true; dpAj9CX(  
} Qp>'V<%m-  
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4`E[WE:Q  
} t&|M@Ouet  
>-8r|};+  
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/* ]hE%Tk-
  
**FileAccess.java 5SV w71*  
*//文件访问(定位，写) c{.y9P6  
package NetFox; C_> WU   
import java.io.*; mq#8[D  
E>LZw>^YJ  
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public class FileAccessI implements Serializable{ ^.3(o{g  
)<ig6b%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 U$,-F**  
RandomAccessFile oSavedFile; m[aBHA^g  
long nPos; iA.:{^_)09  
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public FileAccessI() throws IOException 9 +1}8"~  
{ #*;G8yV  
this("",0); EBQ,Ypv  
} aI.5w9  
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public FileAccessI(String sName,long nPos) throws IOException Rtywi}VV2  
{ r0^*|+   
oSavedFile = new RandomAccessFile(sName,"rw"); $Gs9"~z?;  
this.nPos = nPos; Cx~,wk;=  
oSavedFile.seek(nPos); ZNfQM&<d  
} eewlK]  
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public synchronized int write(byte[] b,int nStart,int nLen) cQzUR^oq,  
{ cnw?3/J  
int n = -1; H8
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try{ 8kdJ;%^N  
oSavedFile.write(b,nStart,nLen); 2^aXXPC  
n = nLen; 2xxw8_~C  
} P>U7RX e  
catch(IOException e) uKA-<nM._c  
{ F ?N+ __o  
e.printStackTrace (); _a]0<Vm C0  
} evSr?ys  
6uS;H]nd<  
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return n; /Fj*sS8  
} 8*x/NaH /\  
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} PAD&s
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/* 5M v<8P~  
**SiteInfoBean.java QZwZ4$jkiO  
*/ tkIpeL[d  
package NetFox; +b sc3  
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G  
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public class SiteInfoBean { |S6L[Uo  
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private String sSiteURL; //Site's URL a&z$4!wQB  
private String sFilePath; //Saved File's Path .;J6)h  
private String sFileName; //Saved File's Name vu@@!cT6e  
private int nSplitter; //Count of Splited Downloading File [,yYr  
d~abWBgC`  
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public SiteInfoBean() Bo+Yu(|cL  
{//nSplitter的缺省值为5 Je*hyi7  
//default value of nSplitter is 5 }PUY~ u  
this("","","",5); a7
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} Oh=
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*<ILSZ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) i'YM9*yN  
{ +/>XOY|Ie  
sSiteURL= sURL; P>nz8NRq  
sFilePath = sPath; 'T+v&M  
sFileName = sName; wh2Ljskda8  
this.nSplitter = nSpiltter; GHRr+  
X
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4+B&/}FDLo  
} tk\)]kj  
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public String getSSiteURL() d3;Sy`.  
{ yPoa04!{=  
return sSiteURL; WRqpQEY  
} N{&Hq4^c  
m)ENj6A>yP  
+JejnG0  
public void setSSiteURL(String value) Ake$M^Bz  
{ Yln[ZmK9g  
sSiteURL = value; !NO)|N>  
} aZ'(ar:  
|hD)=sCj  
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public String getSFilePath() [:MFx6  
{ 0bfJD'^9RP  
return sFilePath; ne|N!!Dmk  
} \Lg{GN.  
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public void setSFilePath(String value) M@=VIrX,m  
{ _/z3QG{Ea^  
sFilePath = value; Hrg -5_  
} 19;Pjo8  
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,lFhLj7  
public String getSFileName() 4 3G2{  
{ z7!@^!r  
return sFileName; UM}MK  
} 2O(= 2X  
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b *Ca*!  
public void setSFileName(String value) |xFSGrC  
{ }qg.Go  
sFileName = value; m](q,65 2  
} #k t+ )>  
=JE5/  
dO!B=/  
public int getNSplitter() 8SN
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{ a9!.e rM
 
return nSplitter; LMaY}m>  
} MDauHtF,  
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public void setNSplitter(int nCount) 1T 8|>2m 3  
{ "?>hQM1R  
nSplitter = nCount; 'MQJt2QU9{  
} *6wt+twH  
} 5Ve T8/7Q  
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ebiOR1)sN  
/* R6`,}<A]@  
**Utility.java yk/BQ|G  
*/ e=Q{CsP  
package NetFox; ~\UAxB=  
{-l:F2i  
|3C5"R3ZGO  
public class Utility { j/, I)Za  
h|N!U/(U  
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public Utility() C zxF  
{ yDw#V`Y^M  
;:aCZ8e  
#@:GLmD%  
} j4+kL4M@H  
xeW}`i5_w  
//线程睡眠 <P_B|Y4N/  
public static void sleep(int nSecond) f,VJfY?#  
{ c^7QiTt_  
try{ ]5+<Rqdbg  
Thread.sleep(nSecond); R]" j
r  
} h@+(VQ  
catch(Exception e) &d=ZCa
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{ MNocXK  
e.printStackTrace (); QFU1l"(qGk  
} "$U!1  
} "bA8NQIP  
9uW\~DwsZ%  
//日志 qsHjqK@(  
public static void log(String sMsg) /{!?e<N>  
{ -5GRit1q?  
System.err.println(sMsg); Jj7he(!_1  
} Rz"
gPU4;`  
.Lp\Jyegs  
Pk^W+M_)~  
public static void log(int sMsg) -aQf(=  
{ fcisD
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System.err.println(sMsg); b$N&sZ  
} c;7`]}
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} kZNVUhW6S  
x%%OgO+>  
i|CAN,'  
/* o,_R;'\E[a  
**TestMethod.java fvr|<3ojo  
*/
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package NetFox; .iZo/_  
`Zd\d:Wyv  
6.
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public class TestMethod { DwIX\9  
KVp3pUO  
+t*Ks_V,*  
public TestMethod() z<,-:=BC"  
{ ///xx/weblogic60b2_win.exe Qw.j  
try{ f~{4hVA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); E\vW>g*W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); />dYkIv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xnPi'?A]  
fileFetch.start(); W6jdS;3  
} c. 06Sw*  
catch(Exception e){e.printStackTrace ();} |`Iispn  
.y>G/8_i  
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} CQ:38l\`gd  
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':DLv
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public static void main(String[] args) %)sG 34  
{ O^sOv!!RH/  
new TestMethod(); xMHu:,ND  
} iDV.C@  
} tV
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