http断点续传简单实现（java)

/* h:iK;  
**SiteFileFetch.java ?\MvAG7Y  
*/ xc.(-g[  
package NetFox; V @A+d[  
import java.io.*; \2(Uqf#_  
import java.net.*; `9a %vN  
"oZ-W?IKE  
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public class SiteFileFetch extends Thread { \F;V69'  
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SiteInfoBean siteInfoBean = null; //文件信息Bean E5D5  
long[] nStartPos; //开始位置 aqq7u5O1
r  
long[] nEndPos; //结束位置 w=.w*?>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PtySPDClj  
long nFileLength; //文件长度 t]|WRQvy8  
boolean bFirst = true; //是否第一次取文件 |~b.rKQt[  
boolean bStop = false; //停止标志 1Wd?AyTY,  
File tmpFile; //文件下载的临时信息 iR;Sd >)  
DataOutputStream output; //输出到文件的输出流 6/`$Y!.ub  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (|DmYn!  
public SiteFileFetch(SiteInfoBean bean) throws IOException S'>(4a  
{ %~`8F\Hiu  
siteInfoBean = bean; 8)IpQG  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2GNtO!B.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0|<ER3xkx  
if(tmpFile.exists ()) 4G`7]<  
{ Ws"eF0,'Z  
bFirst = false; gBQK  
read_nPos(); $\kqh$")  
} 4fPbwiKj  
else =h,6/cs  
{ +]^6&MqO  
nStartPos = new long[bean.getNSplitter()]; Pt~mpRlH
 
nEndPos = new long[bean.getNSplitter()]; s@^(1g[w`  
} f/t1@d!  
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} dI'cZt~n  
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public void run() 
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{ {2<A\nW  
//获得文件长度 OQ&?^S`8',  
//分割文件 0PIiG-o9  
//实例FileSplitterFetch f`w$KVZ1!w  
//启动FileSplitterFetch线程 EgO=7?(pW  
//等待子线程返回 Hn"xn79nc  
try{ __HPwOCG7  
if(bFirst) ))"J  
{ s[h& Uv"G  
nFileLength = getFileSize(); 2 2K:[K  
if(nFileLength == -1)  DJ?kQ  
{ X]6Hgz66  
System.err.println("File Length is not known!"); JBa( O-T  
} 1<#J[$V  
else if(nFileLength == -2) :#8#tLv  
{ ~~eR,HYk  
System.err.println("File is not access!"); Sc Uh -y_  
} T_ifDQX;  
else icW?a9b&  
{ ,H!E :k  
for(int i=0;i<nStartPos.length;i++) L~N<<8?\   
{ ]O Nf;RH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L}O_1+b  
} 5:(uD3]  
for(int i=0;i<nEndPos.length-1;i++) g3~e#vdz  
{ rZ<n0w  
nEndPos = nStartPos[i+1]; S;DqM;Q  
} v;.7-9c*  
nEndPos[nEndPos.length-1] = nFileLength; kL;sA'I:S  
} \s
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} *:r@-=M3=  
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fD1J@57  
//启动子线程 eqz#KN`n#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Mx<V;GPm  
for(int i=0;i<nStartPos.length;i++) c>+l3&`  
{ 7FL!([S5i  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d~f_wN&r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J6Uo+0S  
nStartPos,nEndPos,i); FHpS?htRy  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j:'sbU  
fileSplitterFetch.start(); g.-{=kZ   
} g:0-`,[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ER0nrTlB<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +92/0
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v%O KOrJ  
nEndPos = " + nFileLength); _l$
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// fileSplitterFetch[nPos.length-1].start(); 
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//等待子线程结束 ^
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//int count = 0; ta`}}I  
//是否结束while循环 *Dx&}"  
boolean breakWhile = false; b#;%TbDF  
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while(!bStop) {+~}iF<%  
{ ;Z]i$Vi_r  
write_nPos(); T
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Utility.sleep(500); hwkm'$}  
breakWhile = true; po@=$HK  
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for(int i=0;i<nStartPos.length;i++) e>`+Vk^Jc  
{ qcau(#I9.  
if(!fileSplitterFetch.bDownOver) )xgOl*D  
{ jd<`W  
breakWhile = false; e1$T%?(&[  
break; E.
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} 5yPw[ EY  
} bup)cX^  
if(breakWhile) Db"jzMW.  
break; vmW >$P  
yV
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//count++; ? <b>2j  
//if(count>4) l-` M 9#  
// siteStop(); y[M<x5  
} 13 `Or(>U  
v x qsK  
_*\:UBZx6  
System.err.println("文件下载结束！"); Fc{M N"  
} )C^ZzmB  
catch(Exception e){e.printStackTrace ();} s;!TB6b@  
} ;Fw{p{7<  
r
8.R?5F@  
lYz{#UX}  
//获得文件长度 VF8pH<  
public long getFileSize() {%g]Ym=  
{ tkT:5O6  
int nFileLength = -1; zN2CI6  
try{ ~qFuS933  
URL url = new URL(siteInfoBean.getSSiteURL()); wrw4Uxq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t>nx#ErS  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9<qAf`  
-'SpSy'_  
38<!Dt+S(,  
int responseCode=httpConnection.getResponseCode(); xgsEJE  
if(responseCode>=400) X>}-UHKV+  
{ 9FB k|g"U)  
processErrorCode(responseCode); C
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return -2; //-2 represent access is error \@")2o+  
} 9!C
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String sHeader; @smjXeFo  
jz CA2N%  
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for(int i=1;;i++) R_?Q`+X  
{ ]w7wwU^^*U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {O24:'K&  
//Utility.log(in.readLine()); 4:1URhE  
sHeader=httpConnection.getHeaderFieldKey(i); WC2sRv4]3  
if(sHeader!=null) D^]g`V*N  
{ hnOo T? V  
if(sHeader.equals("Content-Length")) 0\W
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{ < cNJrer  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L\)GPTo!x  
break; Y!!w*G9b  
} :SBB3G)|  
} [wp(s2=  
else mdzUL d5J  
break; -8Z;s8ACo  
} gJ \CT'/  
} ngmHiI W  
catch(IOException e){e.printStackTrace ();} ,3+#?H  
catch(Exception e){e.printStackTrace ();} HLYog+?  
 ,2yIKPWk  
](%EQ[  
Utility.log(nFileLength); JDbRv'F:(  
{|!> {  
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return nFileLength; {,:yZ&(  
} EV=/'f[++  
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//保存下载信息（文件指针位置） '!\t!@I$  
private void write_nPos() _k'?eZB  
{ aK|],L  
try{ 2~ [  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'ozu4y  
output.writeInt(nStartPos.length); _tba:a(  
for(int i=0;i<nStartPos.length;i++) %s&"gWi  
{ 0j\} @  
// output.writeLong(nPos); }\#u~k!l  
output.writeLong(fileSplitterFetch.nStartPos); qcVmt1"
 
output.writeLong(fileSplitterFetch.nEndPos); ;RR\ Hwix  
} $p(  
output.close(); 7XM:4whw  
} ;W~H|M  
catch(IOException e){e.printStackTrace ();} Bp:PAy  
catch(Exception e){e.printStackTrace ();} $kAal26z  
} 3Gk\3iU!  
zG^|W8um_  
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//读取保存的下载信息（文件指针位置） Ef)v("'w  
private void read_nPos() zWO!z=  
{ |K.J@zW  
try{ s~i73Qk/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @IE.@1  
int nCount = input.readInt(); {JGXdp:SB  
nStartPos = new long[nCount]; jjJvyZi~J  
nEndPos = new long[nCount]; UlNx5l+k  
for(int i=0;i<nStartPos.length;i++) }.L:(z^L,Y  
{ m#Y[EPF=|  
nStartPos = input.readLong(); #MyF 1E  
nEndPos = input.readLong(); 8wH1x .  
} ^n%
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input.close(); \281X  
} kac-@  
catch(IOException e){e.printStackTrace ();} (C9{|T+h  
catch(Exception e){e.printStackTrace ();} :|&S7
&l]  
} ~rfUqM]I   
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private void processErrorCode(int nErrorCode) ;owU]Xk%8K  
{ }q?*13iy(  
System.err.println("Error Code : " + nErrorCode); };m.8(}$)  
} q9gk:Jt  
#Fkn-/nL  
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//停止文件下载 tNf_,]u  
public void siteStop() q;Rhx"x>T  
{ ZCAg)/  
bStop = true; ./qbWr`L  
for(int i=0;i<nStartPos.length;i++) 7X{@$>+S  
fileSplitterFetch.splitterStop(); MhDPf]` Gg  
J
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} zqCr'$  
} P0c6?K6 j  
//负责部分文件的抓取 fG"4\A  
**FileSplitterFetch.java kNg{  
*/  [1Q:  
package NetFox; AMe_
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import java.io.*; F9J9zs*,  
import java.net.*; H tx)MEZ  
p)c"xaTP#F  
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public class FileSplitterFetch extends Thread { %) /Bl.{}<  
70F(`;  
? 4v"y@v  
String sURL; //File URL X,`^z,M%I  
long nStartPos; //File Snippet Start Position mV;)V8'  
long nEndPos; //File Snippet End Position gg?O0W{  
int nThreadID; //Thread's ID LZ4Z]!V  
boolean bDownOver = false; //Downing is over R+<M"LriR&  
boolean bStop = false; //Stop identical =<.h.n  
FileAccessI fileAccessI = null; //File Access interface j"Z9}F@  
5E!Wp[^  
?WBA:?=$58  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0?w
4  
{ AVO$R\1YR  
this.sURL = sURL; O_P8OA#|  
this.nStartPos = nStart; fX/k;0l  
this.nEndPos = nEnd; 4c,{Js  
nThreadID = id; 91oAg[@4G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +![\7  
} l<UJ@XID$  
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-~TgA*_5]  
public void run() |>v8yS5  
{ Gj- *D7X5  
while(nStartPos < nEndPos && !bStop) MT^krv(G  
{ F3=iyiz6  
? oQ_qleuo  
*?R<gWCF  
try{ gE$@:j  
URL url = new URL(sURL); *n*po.Xr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w9,w?
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httpConnection.setRequestProperty("User-Agent","NetFox"); CuAA)Bj  
String sProperty = "bytes="+nStartPos+"-"; V\/5H~L  
httpConnection.setRequestProperty("RANGE",sProperty); yIf>8ed]#  
Utility.log(sProperty); J%1 2Ey@6  
i{MzQE+_^  
IJ2>\bW_p  
InputStream input = httpConnection.getInputStream(); f}:W1&LhI?  
//logResponseHead(httpConnection); \w=*:Z  
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+8 }p-<a  
byte[] b = new byte[1024]; Rf#t|
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int nRead; :rnj>U6<>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) s}Q*zy  
{ Ixr#zt$T-G  
nStartPos += fileAccessI.write(b,0,nRead); $@eFSA5k,7  
//if(nThreadID == 1) F2C v,&'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Yg!xlrxA  
} c.Do b?5  
]GmXZi  
j9O"!9$vQ  
Utility.log("Thread " + nThreadID + " is over!"); T?EFY}
f  
bDownOver = true; tS sDW!!M  
//nPos = fileAccessI.write (b,0,nRead); #RTiWD[o  
} oF=UjA  
catch(Exception e){e.printStackTrace ();} q:3HU<  
} ,7^,\ ,-m  
} -3|i5
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}
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9RnXp&w  
//打印回应的头信息 Na>?1F"KHk  
public void logResponseHead(HttpURLConnection con) qA
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{ a{4RG(I_  
for(int i=1;;i++) y R_x:,|g  
{ 95^-ptO{1`  
String header=con.getHeaderFieldKey(i); (a@}J.lL  
if(header!=null) F:cenIaBF  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (6~~e$j  
Utility.log(header+" : "+con.getHeaderField(header)); k-|b{QZ8!;  
else $?dutbE  
break; k%h%mz  
} T)#eaz$4W  
} $
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rhO8v  
{"@E_{\  
public void splitterStop() +^V%D!.$@  
{ I>%@[h,+  
bStop = true; {GKqOu  
} rEY5,'?YHv  
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} @>Ul0&Mf?  
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/* vw
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**FileAccess.java x[1(cj  
*//文件访问(定位，写) &46Ro|XE`  
package NetFox; PtT$#>hx]  
import java.io.*; )d"s6i
 
` EgO&;1D)  
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public class FileAccessI implements Serializable{ 1`l10fqU  
QP1bm]QYA  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 TI^M9;b  
RandomAccessFile oSavedFile; jjU("b=  
long nPos; NiO|Aki{  
)@\m0bnF  
4KT-U6zNx  
public FileAccessI() throws IOException UWW_[dJr  
{ hwB>@r2  
this("",0); M$+2f.(>k)  
} Y|y X]\,  
V;>u()
 
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public FileAccessI(String sName,long nPos) throws IOException q3$;lLsb;j  
{ q?2kD"%$  
oSavedFile = new RandomAccessFile(sName,"rw"); @Yy']!Ju  
this.nPos = nPos; H/BU2sa  
oSavedFile.seek(nPos); b8TwV_&|X  
} dT4e[4l  
=~F.7wq*^  
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public synchronized int write(byte[] b,int nStart,int nLen) 6n5>{X  
{ HA::(cXL  
int n = -1; HT6+OK(~dJ  
try{ us3f
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oSavedFile.write(b,nStart,nLen); -3eHJccB  
n = nLen; )kuw&SH,  
} E1V;eoK.D  
catch(IOException e) (#%R'9Rv  
{ `o,D[Jd  
e.printStackTrace (); LSN%k5G7.  
} Tv`-h  
kr6^6
I.  
H_+F~P5RC  
return n; 84UI)nE:Q  
} ?~s23%E  
*d;D~"E<@  
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} R8YA"(j!L  
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L2m~ GnP|?  
/* u=9)A9  
**SiteInfoBean.java R6/vhze4L2  
*/ 7d"gRM;  
package NetFox; X'KkIo :  
9;k!dM  
^lCQHz  
public class SiteInfoBean { F^)SQ%xx  
t ]yD95|  
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private String sSiteURL; //Site's URL o6~9.~_e  
private String sFilePath; //Saved File's Path dLIZ)16&  
private String sFileName; //Saved File's Name c<n <!!
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private int nSplitter; //Count of Splited Downloading File *g;4?_f  
0'O*Y ]h+  
:KL5A1{  
public SiteInfoBean() 1xF<c<  
{//nSplitter的缺省值为5 Z$&i"1{  
//default value of nSplitter is 5 dJYQdo^X  
this("","","",5); Bm&%N?9  
} \"^.>+  
{^qp
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -yH8bm'0"  
{ FELTmQUV  
sSiteURL= sURL; I:9jn"  
sFilePath = sPath; Lm}J&^>  
sFileName = sName; eFiUB  
this.nSplitter = nSpiltter; &@anv.D  
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O.g!k"nas&  
} 9X6l`bo'  
Jf|6 FQo&  
eX9Hwq4X44  
public String getSSiteURL() 
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{ lqe71](sK8  
return sSiteURL; ddiBjp2.!  
} 07:N)y,  
aur4Ky> :  
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public void setSSiteURL(String value) si|DxDx  
{ ;`P}\Q{  
sSiteURL = value; d:V6.7>,  
} /o)o7$6Q  
fX[6  {  
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public String getSFilePath() "2~%-;c  
{ RN"O/b}qQ  
return sFilePath; %W[#60  
} O3>m,v  
TUaW'  
"X7;^yY  
public void setSFilePath(String value) Q lg~S1D_v  
{ C0bOPn  
sFilePath = value; %m5&U6  
} I/ q>c2Pw$  
^&mJDR
e  
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public String getSFileName() #^FDFl  
{ ILQB%0!  
return sFileName; |`50Tf\J  
} 'QrvkQ  
Z
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%tRQK$]c  
public void setSFileName(String value) ?\D=DIN-r  
{ 8A3pYW-  
sFileName = value; HI}9"(t}  
} !u;r<:g!  
zu@5,AH  
z#!}4@_i3  
public int getNSplitter() w6 x{<d  
{ m)aNuQvy:Z  
return nSplitter; f
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} _Ka6! 9  
D'!
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public void setNSplitter(int nCount) _poe{@h!  
{ AM ZWPU  
nSplitter = nCount; 'l| e}eti>  
} J"&jR7-9  
} WLe9m02r  
7Ib/Cm0d|  
}}g.L|  
/* V>YZ^>oeH  
**Utility.java Ym WVb  
*/ Y,%d_yR
[  
package NetFox; -!kfwJg8N(  
=h<LlI^v  
v_$'!i$  
public class Utility { 7oK7f=*Q  
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|QIFtdU5T  
public Utility() wf= s-C  
{ ^^-uq)A  
W_ =  
SX4"HadV>  
} P})Iwk|Z  
8<VO>WA>E  
//线程睡眠 L:(>O
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public static void sleep(int nSecond) F{g^4  
{ {4@+ 2)l  
try{ *nPB+
@f  
Thread.sleep(nSecond); DD4fV`:kG  
} fW,,@2P  
catch(Exception e) b&l/)DU  
{ &%ZiI@O-  
e.printStackTrace (); *XCid_{(  
} o?Wp[{K  
} h5:>o  
m\}8N u  
//日志 d0;$k,  
public static void log(String sMsg) yz CQ  
{ jBTXs5q  
System.err.println(sMsg); J9kmIMq-C  
} FHu -';  
;0R>Dg  
krw_1Mm  
public static void log(int sMsg) c:R`]4o  
{ Dj~]]  
System.err.println(sMsg); Y~</vz+H  
} y$]gmg  
} 0x-58i0  
"0nT:!BZ  
bvu
oo/  
/* @Y~R*^n"}  
**TestMethod.java |9;6Cp  
*/ ,EAf/2C  
package NetFox; !&3iZQGWv  
~is$Onf99#  
vtv^l3  
public class TestMethod { JVoW*uA  
$E
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}[[  
public TestMethod() TH`zp]0  
{ ///xx/weblogic60b2_win.exe _ 2WG6y;  
try{ |7K[+aK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qNLG-m,n<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :< )"G&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); q]-CTx$  
fileFetch.start(); j#C1+Us  
} p;GT[Ds^  
catch(Exception e){e.printStackTrace ();} d"1DE  
4@qKML  
C;T:'Uws  
} =*AAXNs@3  
>#q2KXh  
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public static void main(String[] args) ,<^7~d{{3m  
{ UogkQ& B  
new TestMethod(); c\n&Z'vK  
} V>{G$(v$  
} \8~P3M":c  
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