http断点续传简单实现（java)

/* Cb i;CF\{  
**SiteFileFetch.java =EQaZ8k  
*/ +8Q5[lh2]j  
package NetFox; |rL#HG  
import java.io.*; ?atHZLF  
import java.net.*; z`2Ais@ao  
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public class SiteFileFetch extends Thread { 
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XgPZcOzYB  
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SiteInfoBean siteInfoBean = null; //文件信息Bean a?]~Sw"@  
long[] nStartPos; //开始位置 W+'f|J=  
long[] nEndPos; //结束位置 !vGJ7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 v%4zP%4Ak[  
long nFileLength; //文件长度 w1:%P36H  
boolean bFirst = true; //是否第一次取文件 dCO7"/IHW  
boolean bStop = false; //停止标志 Nf1&UgX  
File tmpFile; //文件下载的临时信息 <uXQT$@?  
DataOutputStream output; //输出到文件的输出流 3!Cab/T  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -oB`v'  
public SiteFileFetch(SiteInfoBean bean) throws IOException sL4+O P-
 
{ CJf4b:SY@  
siteInfoBean = bean; KF}_|~~T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,nGZ(EBD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); '~n=<Y  
if(tmpFile.exists ()) M|IgG:a;T  
{ W&p f%?  
bFirst = false; iL;{]A'0  
read_nPos(); ?(E?oJ)(  
} i/aj;t
  
else %R@&8  
{ ^.u J]k0  
nStartPos = new long[bean.getNSplitter()]; K?gO]T{6  
nEndPos = new long[bean.getNSplitter()]; ?a{>QyL  
} l;vA"b=]  
Dy^A??A[E}  
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} TQsTL2a  
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public void run() =aCd,4B}  
{ R~N'5#.*M  
//获得文件长度 ~NBlJULS  
//分割文件 !DZ4C.  
//实例FileSplitterFetch 0*50uK=5  
//启动FileSplitterFetch线程 mL3 Q  
//等待子线程返回 *ez7Q  
try{ Gn>~CoFN  
if(bFirst) (tzfyZ M  
{ {IT;g9x  
nFileLength = getFileSize(); ;`rz]7,*  
if(nFileLength == -1) /9(8ML#E  
{ *(j-jbA  
System.err.println("File Length is not known!"); L,*#  
} AN4(]_]  
else if(nFileLength == -2) TM0DR'.  
{ *@[N~:z/  
System.err.println("File is not access!"); ?oulQR6:  
} 0w ;#4X:m  
else V<0J j  
{ FXo{|z3  
for(int i=0;i<nStartPos.length;i++) L;'C5#GN  
{ }(v <f*7=n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R\:t 73  
} 02mu%|"  
for(int i=0;i<nEndPos.length-1;i++) ;1L7+.A  
{ (qg~l@rf  
nEndPos = nStartPos[i+1]; f<l.%B  
} g33Y]\  
nEndPos[nEndPos.length-1] = nFileLength; @j+X>TD  
} .R{
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} $Y<(~E
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>&l{_b\k  
(5&l<u"K~  
//启动子线程 O*-sSf   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vC_O!2E  
for(int i=0;i<nStartPos.length;i++) "7_qB8\  
{ 73tWeZ8rvx  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gfmaO]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ps9YP B-  
nStartPos,nEndPos,i); Cswa5l`af  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >TddKR@C  
fileSplitterFetch.start(); ^9xsbv B0  
} (]*!`(_b  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~.
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 77o&$l,A|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6jo+i[h  
nEndPos = " + nFileLength);
~#V1Gunq  
// fileSplitterFetch[nPos.length-1].start(); B)L;ja  
\|q.M0  
HP*AN@>Kw  
//等待子线程结束 A
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//int count = 0; E!v^j=h$u  
//是否结束while循环 *r]Mn~3  
boolean breakWhile = false; 7COJ.rA  
N~@VZbS(6  
+yYSp8>  
while(!bStop) >"z&KZKI  
{ o
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write_nPos(); \~`qE<Q/  
Utility.sleep(500); (VA:`pstP  
breakWhile = true; UONW3}-  
."\&;:ZNv  
hg=BXe4:  
for(int i=0;i<nStartPos.length;i++) Pw_[{LL  
{ Rooem dCM  
if(!fileSplitterFetch.bDownOver) Z,bvD'u  
{ 8GD!]t#  
breakWhile = false; hr] :bR  
break; 0kB!EJ<OdG  
} 8{Id+Q>Vo,  
} ,0R2k `m!  
if(breakWhile) ooPH [p  
break; WxFrqUz  
)wwQv2E  
63?fn~0\  
//count++; ]Ak@!&hyak  
//if(count>4) ^"d!(npw  
// siteStop(); );.q:"  
} %wp#vO-$  
&JpFt^IHi  
GL_a`.=@  
System.err.println("文件下载结束！"); boR&'yX  
} ,~_)Cf#CB  
catch(Exception e){e.printStackTrace ();} "jUr[X2J  
} S6
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>cPB:kD'  
3eg<)  
//获得文件长度 _~`\TS8  
public long getFileSize() <E|K<}W#  
{ .qioEqK8!y  
int nFileLength = -1; i7[CqObzc  
try{ 
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URL url = new URL(siteInfoBean.getSSiteURL()); X]Emz"   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y/m^G=Q6g#  
httpConnection.setRequestProperty("User-Agent","NetFox"); $e|G#mMd-  
_F *(" o  
w 1
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int responseCode=httpConnection.getResponseCode(); Oifu ?f<r  
if(responseCode>=400) L30x2\C  
{ :ji_dQ8k  
processErrorCode(responseCode); ~7!J/LHg  
return -2; //-2 represent access is error b\%=mN
 
} KZL5>
E  
?'K}bmdt}.  
'r%`(Z{~  
String sHeader; QK\QvU2y  
sa`7_KB  
?rQ
MOJR  
for(int i=1;;i++) Lrz>0_Q  
{ )Xa`LG=|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); I~qS6#%r  
//Utility.log(in.readLine()); Hi{c[;  
sHeader=httpConnection.getHeaderFieldKey(i); yg "u^*r&  
if(sHeader!=null) ]do0{I%\eq  
{ ke~O+]  
if(sHeader.equals("Content-Length")) 6:B[8otQ  
{ {W}.z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Um\Nd#=:  
break; !>/U6
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} T IPb ]  
} nD.4c-hd$q  
else H!&]Di1Eh  
break; KMznl=LF  
}  :XF;v  
} @4h .?  
catch(IOException e){e.printStackTrace ();} MyuFZ7Q4$  
catch(Exception e){e.printStackTrace ();} $qy%Q]  
!l_1r$  
r M'snW)  
Utility.log(nFileLength); #:z.Br`  
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return nFileLength; VbK| VON[  
} g`gH]W FcG  
+"T?.,  
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//保存下载信息（文件指针位置） 6{
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private void write_nPos() Ve7[U_"  
{ UBi0 /  
try{ M'HmVg4'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <<v,9*h  
output.writeInt(nStartPos.length); _7]*
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for(int i=0;i<nStartPos.length;i++) lW?}jzuo  
{ ar=uDb;  
// output.writeLong(nPos); bKmR &  
output.writeLong(fileSplitterFetch.nStartPos); c5<M=
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output.writeLong(fileSplitterFetch.nEndPos); (<(8(}x  
} vz,l{0v  
output.close(); Tw`^  
} DK&J"0jz,  
catch(IOException e){e.printStackTrace ();} Cz Jze  
catch(Exception e){e.printStackTrace ();} =cM\o{ q  
} Dx/?0F7V  
RXb+"/  
%-i2MK'A  
//读取保存的下载信息（文件指针位置） 7 \!t/<  
private void read_nPos() zm9>"(H  
{ ^4O1:_|G  
try{ }9aYU;9D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); l^%Ez?-:s  
int nCount = input.readInt(); K]oFV  
nStartPos = new long[nCount]; *rK}Ai  
nEndPos = new long[nCount]; /^i7^  
for(int i=0;i<nStartPos.length;i++) 7*M+bZ`x  
{ 60*2k  
nStartPos = input.readLong(); &o= #P2Qd  
nEndPos = input.readLong(); 7pMrYIP  
} %/CCh;N#  
input.close(); *ELbz}Q  
} 0j
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catch(IOException e){e.printStackTrace ();} \&`S~cV9  
catch(Exception e){e.printStackTrace ();} -{>JF  
} LS+ _y<v=  
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>93vMk~hU  
private void processErrorCode(int nErrorCode) 4)!aYvaER  
{ (2[tQ`~  
System.err.println("Error Code : " + nErrorCode); d0"Hu^]  
} ^J< I Ia4  
t Q385en  
0WaC.C+2i  
//停止文件下载
$5jQm,V$K  
public void siteStop() ']WS@MbJ  
{ 9i*t3W71]  
bStop = true; WId"2W3M  
for(int i=0;i<nStartPos.length;i++) L%}k.)yev  
fileSplitterFetch.splitterStop(); aJ}y|+Cj  
5f(yF  
+)h*)  
} 7+0Kg'^+n  
} 'X d_8.  
//负责部分文件的抓取 !1$QNx
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**FileSplitterFetch.java pwtB{6)VH{  
*/ c Owa^;  
package NetFox; RZ-=UIf  
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import java.io.*; y3{'s>O6  
import java.net.*; 18f!k  
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public class FileSplitterFetch extends Thread { +:k Iq  
@/FE!6 |O  
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String sURL; //File URL e&sZ]{uD  
long nStartPos; //File Snippet Start Position yB0xa%  
long nEndPos; //File Snippet End Position }K':tX?  
int nThreadID; //Thread's ID 
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boolean bDownOver = false; //Downing is over .<7M4Z  
boolean bStop = false; //Stop identical
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FileAccessI fileAccessI = null; //File Access interface  kDbDG,O  
ntR@[)K  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eB%hP9=:x  
{ $cjwY$6  
this.sURL = sURL; W%&t[_21  
this.nStartPos = nStart; t|-TG\Q X  
this.nEndPos = nEnd; 7[z^0?Pygf  
nThreadID = id; R9XISsM^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 O&BNhuW2  
} .)=T1^[hI  
:{sy2g/+  

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public void run() "/H B#  
{ "#}
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while(nStartPos < nEndPos && !bStop) ]JDKoA{S0  
{ ~EIK  
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>A&D/kMO  
try{ MpY/G%3  
URL url = new URL(sURL); p+
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~dc o  
httpConnection.setRequestProperty("User-Agent","NetFox"); xXb7/.*qE  
String sProperty = "bytes="+nStartPos+"-"; ul(pp+%S  
httpConnection.setRequestProperty("RANGE",sProperty); Q9T/@FX  
Utility.log(sProperty); !s^[|2D_U  
VT ikLuH  
h]
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InputStream input = httpConnection.getInputStream(); xWRkg$A  
//logResponseHead(httpConnection); 7QSrC/e  
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(1%O;D.*?{  
byte[] b = new byte[1024]; !LI 8Xk  
int nRead; B`<a~V  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o|7ztpr  
{ 0*J},#ba$  
nStartPos += fileAccessI.write(b,0,nRead); *ggai?  
//if(nThreadID == 1) xg(*j[ff3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \u4`6EYF?  
} pNFVa<D  
DpbprT7_  
e^=b#!}-5:  
Utility.log("Thread " + nThreadID + " is over!"); c`Q#4e]%_  
bDownOver = true; R6cd;| fan  
//nPos = fileAccessI.write (b,0,nRead); x@*RF:\}  
} F_I.=zQr  
catch(Exception e){e.printStackTrace ();} YMG~k3Yb  
} #i;y[dQ  
} ~o8  
]]Fe:>  
#1)#W6 h\  
//打印回应的头信息 >,6%Y
3  
public void logResponseHead(HttpURLConnection con) $V870 <  
{ SX)o0v+  
for(int i=1;;i++) vu@@!cT6e  
{ <dWms`QcO  
String header=con.getHeaderFieldKey(i); 4k_y;$4WN  
if(header!=null) W0+m A  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <SKz
Cp\  
Utility.log(header+" : "+con.getHeaderField(header)); Oh=
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else A.+Qa  
break; 1v~1?+a\2  
} 9,jFQb(),  
} ~ugyUpY"  
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public void splitterStop() ,p' ;Xg6ez  
{ 4^GIQEjx  
bStop = true; PfN[)s4F{R  
} rM0Idc.$&&  
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} rI#,FZ  
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/k.?x]Ab  
/* _ SJFuv/  
**FileAccess.java ;; ?OS  
*//文件访问(定位，写) 7r{159&=  
package NetFox; p~yGp]yJ9  
import java.io.*; /_mU%fl  
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public class FileAccessI implements Serializable{ 4 3G2{  

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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 .#{m1mr  
RandomAccessFile oSavedFile; b *Ca*!  
long nPos; 534DAhpD=.  
~COd(,ul  
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public FileAccessI() throws IOException JIXZI\Fk  
{ 85rjM#~
  
this("",0); G O[u  
} *6wt+twH  
d`3>@*NR<  
^=arKp,?5  
public FileAccessI(String sName,long nPos) throws IOException 7g.3)1  
{ )sLXtV)nm6  
oSavedFile = new RandomAccessFile(sName,"rw"); .zo>,*:t  
this.nPos = nPos; S\0?~l"}  
oSavedFile.seek(nPos); Rg7~?b-  
}  zt2#6v  
!"SuE)WM  
5GwzG<.\^_  
public synchronized int write(byte[] b,int nStart,int nLen) 1q/Q@O  
{ AEo  
int n = -1; I`q"  
try{ M,g
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oSavedFile.write(b,nStart,nLen); @i(;}rx  
n = nLen; ~y>NJM>1  
} /{!?e<N>  
catch(IOException e) w0,rFWS  
{ eVRjU  
e.printStackTrace (); ,IRy. qy  
} '7UIzk|  
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return n;
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} :\KJw  
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} ,2]a<0m  
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6.
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/* p_qJI@u8  
**SiteInfoBean.java A;
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*/ E&>=  
package NetFox; /XXy!=1J  
!1xX)XD4y  
Ax'o|RE)x  
public class SiteInfoBean { %Mr^~7nN  
c. 06Sw*  
=v7%IRP5  
private String sSiteURL; //Site's URL x"{WLZ  
private String sFilePath; //Saved File's Path 4(TR'_X(  
private String sFileName; //Saved File's Name ':DLv
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private int nSplitter; //Count of Splited Downloading File 2)(ynrCe  
xMHu:,ND  
52q<|MW%  
public SiteInfoBean() $kd9^lj#[  
{//nSplitter的缺省值为5 eY8rm  
//default value of nSplitter is 5 ,g:\8*Y>'  
this("","","",5); 4x2,X`pe3  
} abkt&981K+  
hv#|dI=kZR  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) s> JW
NP  
{ 5?XIp6%x  
sSiteURL= sURL; m.w.h^f$&  
sFilePath = sPath; ?V' zG&n@  
sFileName = sName; ` *q>E  
this.nSplitter = nSpiltter; }N0v_Nas;v  
]h?p3T$h  
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}
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nj
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I8Q!`KJ  
public String getSSiteURL() mY&(&'2T"  
{ fzjAP7 y  
return sSiteURL; B3'-:  
} m#`1.5%  
~zhP[qA})  
rObg:(z&\  
public void setSSiteURL(String value) DE!c+s_g4  
{ dzs(sM=  
sSiteURL = value; THY=8&x)  
} xP-\)d-.aN  
4x|\xg( l  
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public String getSFilePath() >b2wFo/em  
{  P@FE3g  
return sFilePath; #D-Ttla  
} <g1=jG:7k  
X ;Cl8  
 B6.9hf  
public void setSFilePath(String value) Jsf"h-)P  
{ rmJ`^6V  
sFilePath = value; 8:fq!m  
} 3gs!ojG  
xTf|u  
wyB  
public String getSFileName() `rb}"V+  
{ <Wm'V-  
return sFileName; w@x||K=Z  
} ~PyZh5x  
Iad&Z8E  
98XlcI#  
public void setSFileName(String value) {ep.So6  
{ 11?d,6Jl  
sFileName = value; `y$@zT?j  
} c' Q4Fzj0'  
<+_WMSf;4  
;k (M4?  
public int getNSplitter() +g&M@8XO&  
{ AmB*4p5b  
return nSplitter; ou=33}uO  
} ET;-'vd  
5#~E[dr  
=0mn6b9-=  
public void setNSplitter(int nCount) ={\9-JJhE  
{ 5xhYOwQBo  
nSplitter = nCount; 6"yIk4u:  
} 95sK;`rE+  
} BMb0Pu
8  
M8${&&[;  
4 {+47=n  
/* ak\[+
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**Utility.java BG/RNem  
*/ NIG* }[}P  
package NetFox; ]/7#[  

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public class Utility { w%$J<Z^-?  
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6|QIzs<Z-X  
public Utility() <=%=,Yk  
{ $:D\yZ,  
(w`j?c1  
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U  
} _8e0vi!~2  
(Q"~bP{F  
//线程睡眠 O@a7MzJ  
public static void sleep(int nSecond) @PV3G KJ  
{ Iz8gZ:rd0  
try{ -nY_.fp>  
Thread.sleep(nSecond); NmTo/5s  
} ?8YbTn1f)  
catch(Exception e) 7MIrrhk  
{ C0W-
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e.printStackTrace (); x{S2   
} {T3~js   
} u5tUm  
e6Kyu*  
//日志 u<EPK*O*  
public static void log(String sMsg) Esf\Bo
"  
{ >3&9Wbv>  
System.err.println(sMsg); i4mP*RwC  
} 4xgfm.9I^  
;&XC*R+  
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public static void log(int sMsg) KgXu x-q  
{ Y?:"nhN  
System.err.println(sMsg); V!QC.D<  
} 3-BC4y/  
} P?+ VR=t  
XO}SPf-  
]>[0DX]j  
/* fa!8+kfi  
**TestMethod.java c|X}[  
*/ V^_U=Ed@M  
package NetFox; zA|)9Dq  
dte-2?%~j  
3\K;y>NK  
public class TestMethod { IEY\l{s  
%$=2tfR  
Px&)kEQ  
public TestMethod() sU/vXweky"  
{ ///xx/weblogic60b2_win.exe XoGOY|2`6  
try{ zN/n
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T$Z}1e]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); o0TB>DX$`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); rLA^ &P:  
fileFetch.start(); x M{SFF  
} `:Zgq+j&  
catch(Exception e){e.printStackTrace ();} 9&{HD  
on 4 $n7  
(#+81 Dr  
} 5m\)82s  
AJ z 1  
=.qPjp_Qd  
public static void main(String[] args) !\\OMAf7  
{ A@e!~  
new TestMethod(); yUs/lI, Q  
} "g5MltH  
} %DKC/%  
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