http断点续传简单实现（java)

/* X{u\|e{  
**SiteFileFetch.java %B~@wcI)W  
*/ L)z`  
package NetFox; 1EemVZdY  
import java.io.*; a/{M2  
import java.net.*; VR XK/dZ  
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T!%J x.^  
public class SiteFileFetch extends Thread { | zyO;  
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v;o/M6GL5  
SiteInfoBean siteInfoBean = null; //文件信息Bean (3Dz'X  
long[] nStartPos; //开始位置 *~\R0ddz  
long[] nEndPos; //结束位置 [e`e bn[C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )>]@@Trx  
long nFileLength; //文件长度 YHOo6syk  
boolean bFirst = true; //是否第一次取文件 M~ku4ZP  
boolean bStop = false; //停止标志 NiSH$MJ_  
File tmpFile; //文件下载的临时信息 @~CXnc0  
DataOutputStream output; //输出到文件的输出流 ^1-Vd5g  
iF*L-  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） I /z`)  
public SiteFileFetch(SiteInfoBean bean) throws IOException GO]5~4k  
{ 5Ly
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siteInfoBean = bean; v+vM:At4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i@L_[d^|j`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); C0}@0c  
if(tmpFile.exists ()) 60#eTo?}o  
{ k@[{_@>4^  
bFirst = false; +GvPJI  
read_nPos(); x(+H1D\W  
} bV&"
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else 6qd?&.=r  
{ =mYw
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nStartPos = new long[bean.getNSplitter()]; Y=ksrs>w  
nEndPos = new long[bean.getNSplitter()]; 80%L!x|  
} e X{#FgFc  
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} n09P!],Xa  
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public void run() U[
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{ aP[oLk$'Z  
//获得文件长度 hEq-)-^G  
//分割文件 ~7>D>!!  
//实例FileSplitterFetch O_ d[{e=5`  
//启动FileSplitterFetch线程 g`(3r  
//等待子线程返回 c<ORmg6  
try{ dwqR,|  
if(bFirst) 1\Z/}FT  
{ 9UCA&n  
nFileLength = getFileSize(); %W^Zob  
if(nFileLength == -1) ?k^~qlye  
{ b8LA|#]i  
System.err.println("File Length is not known!"); 4x-
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} yVe<+Z\7  
else if(nFileLength == -2) dK41NLGQ  
{ bJcO,M:2  
System.err.println("File is not access!"); "i,ZG$S#E  
} ZkryoIQ%=  
else :[&QoEZW  
{ l?B=5*0  
for(int i=0;i<nStartPos.length;i++) 2j&0U!DX  
{ M.67[Qj~"u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $DW__h  
} Ot{~mMDp  
for(int i=0;i<nEndPos.length-1;i++) 5><T#0W?  
{ <DN7  
nEndPos = nStartPos[i+1]; _9y!,ST  
} DMA`Jx  
nEndPos[nEndPos.length-1] = nFileLength; FEdFGT  
} @rS(3wu_&  
} 9v/=o`J#  
'fYF1gR4  
#$;}-*  
//启动子线程 _%u t#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gh `]OxA  
for(int i=0;i<nStartPos.length;i++) ~?:>=x  
{ V8rS~'{\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =~TPrO^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?&=JGk^eJ  
nStartPos,nEndPos,i); "?^#+@LV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <k 'zz:[c!  
fileSplitterFetch.start(); 4BZ7R,m#.  
} [r1dgwh8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c8Nl$|B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Nw '$r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q^8/"aV\  
nEndPos = " + nFileLength); mFmx
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// fileSplitterFetch[nPos.length-1].start(); tL M@o|:  
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//等待子线程结束 (duR1Dz  
//int count = 0; [Z^26/5a  
//是否结束while循环 7Vuf4Z5  
boolean breakWhile = false; gs&F .n  
nrR2U`  
&crR nv?  
while(!bStop) K >Q6  
{ m'-QVZ{(M%  
write_nPos(); qERJEyU?  
Utility.sleep(500); &W3Hj$>  
breakWhile = true; <cxe   
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[6Q1yNE  
for(int i=0;i<nStartPos.length;i++) M)~sL1)  
{ ]X> I(p@  
if(!fileSplitterFetch.bDownOver) BO2s(8  
{ R$`%<Y3)  
breakWhile = false; rX0 ?m:&m  
break; R'pfA B|!  
} MDBqIL]Hc  
} ~~@dbB  
if(breakWhile) %,S{9q  
break; o]WcODJdl  
%Fx^"  
UOyM=#ipY  
//count++; J%lrXm(l{  
//if(count>4) ^r,0aNzAs  
// siteStop(); |;\pAZ2  
} y&/bp<Z  
MnlD87x@X  
]WK~`-3C^  
System.err.println("文件下载结束！"); ZYt1V"2VJ  
} cG&@PO]+.  
catch(Exception e){e.printStackTrace ();} hcM9Sx"!  
} B4*uS (  
kgI8PybY  

!ST7@D  
//获得文件长度 {9* l  
public long getFileSize() }$[@*  
{ T\#Gc4  
int nFileLength = -1; 7yjun|Lt}X  
try{ I>q!co9n  
URL url = new URL(siteInfoBean.getSSiteURL()); H^dw=kS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tN.$4+  
httpConnection.setRequestProperty("User-Agent","NetFox"); hiv {A9a?  
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int responseCode=httpConnection.getResponseCode(); qMoo#UX  
if(responseCode>=400) xUNq!({T  
{ 5gkQ6&m  
processErrorCode(responseCode); /N#=Tol  
return -2; //-2 represent access is error hAt4+O&P  
} Lq2jXy5#n  
`
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^j@+!A_.Q  
String sHeader; 'u%vpvF  
W.%p{wB|  
8llXpe  
for(int i=1;;i++) LG:d  
{ XpYd
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); X(BX+)YR  
//Utility.log(in.readLine()); M!i*DU+SE  
sHeader=httpConnection.getHeaderFieldKey(i); *sau['Ha  
if(sHeader!=null) RF;[:[*W  
{ OT(0~,.GJ  
if(sHeader.equals("Content-Length")) y}is=h3  
{ ~0[(-4MA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0$0 215  
break; p+5J  
} jT/P+2hMW  
} p2< 927z  
else #;5Qd'  
break; hk$I-  
} j5og}P
q:  
} JH u>\{8V  
catch(IOException e){e.printStackTrace ();} bxzx@sF2l  
catch(Exception e){e.printStackTrace ();} $:# :"  
w~&#:F?
  
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Utility.log(nFileLength);  ?!<Q8=  
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return nFileLength; 5;G0$M0  
} J{\(Y#|rHs  
&['L7  
Mlr'h}:H  
//保存下载信息（文件指针位置） ?|pP&8r  
private void write_nPos() jE=m4
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{ c`&g.s@N\  
try{ R4T@ ]l&W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); R]o0V*n  
output.writeInt(nStartPos.length); Z9MR"!0  
for(int i=0;i<nStartPos.length;i++) NFP h}D  
{ R*D5n>~  
// output.writeLong(nPos); *]}F=dtR k  
output.writeLong(fileSplitterFetch.nStartPos); `'*4B_.  
output.writeLong(fileSplitterFetch.nEndPos); rA^=;?7Q  
} ?6>*mdpl  
output.close(); +>%51#2.Q  
} 8'_MCx(  
catch(IOException e){e.printStackTrace ();} +v'2s@e` #  
catch(Exception e){e.printStackTrace ();} =v'Aub  
} 4[&&E7
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N8k=c3|  
5UOqS#"0  
//读取保存的下载信息（文件指针位置） 2b,edJVt?  
private void read_nPos() Lb?q5_  
{ )q.ZzijG/  
try{ 'U*#71S  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); dh.{lvlX|  
int nCount = input.readInt(); .t8hTlV?<B  
nStartPos = new long[nCount]; /I1n${{5  
nEndPos = new long[nCount]; 'rS\9T  
for(int i=0;i<nStartPos.length;i++) ,qo^G0XO  
{ Ke3~o
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nStartPos = input.readLong(); E:k]Z  
nEndPos = input.readLong(); (+0(A777M  
} %W$b2N{l  
input.close(); .o5K X*  
} BTYYp1  
catch(IOException e){e.printStackTrace ();} P-$ ,  
catch(Exception e){e.printStackTrace ();} = Ezg3$%-  
} KATf9-Sz  
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xIW]e1pu=(  
private void processErrorCode(int nErrorCode) <Rs$d0/  
{ .C5<uW5-R  
System.err.println("Error Code : " + nErrorCode); n~BQq-1  
} SIKaDIZ  
w{lj'3z I  
:-lq Yd5^  
//停止文件下载 DU)q]'[u  
public void siteStop() tQYV4h\Qj  
{ eK5~gnv,  
bStop = true; 0I:5}$+J?  
for(int i=0;i<nStartPos.length;i++) zUDXkG*Lv  
fileSplitterFetch.splitterStop(); Y0-?"R8  
+?ZP3vgGA  
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} HmkxE  
}
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//负责部分文件的抓取 |(TEG.<g  
**FileSplitterFetch.java nd,\<}uP9  
*/ \x:U`T  
package NetFox; {Rb;1 eYj  
)V+/@4  
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import java.io.*; =R 4]Kf  
import java.net.*; 2xiE#l-V2  
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public class FileSplitterFetch extends Thread { *JZ9'|v_H  
v _:KqdmO]  
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String sURL; //File URL `8#xO{B1  
long nStartPos; //File Snippet Start Position 5Ma."?rW   
long nEndPos; //File Snippet End Position o0F,!}  
int nThreadID; //Thread's ID [`s.fk
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boolean bDownOver = false; //Downing is over 1*$6u5.=F  
boolean bStop = false; //Stop identical __s'/6u  
FileAccessI fileAccessI = null; //File Access interface
|,S]EHIy  
nUVk;0at  
ut]UU*g^$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N!ay#V  
{ ,UC|[-J  
this.sURL = sURL; m\CU,9;;(  
this.nStartPos = nStart; 6R8>w,  
this.nEndPos = nEnd; :;hX$Qz  
nThreadID = id; !>ZBb\EyK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fx4#R(N  
} g:xg ~H2  
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{Y=k`t,  
public void run() AZ^
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{ *?C8,;=2r  
while(nStartPos < nEndPos && !bStop) 4M|C>My  
{ {06ClI  
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try{ ]N0B.e~D  
URL url = new URL(sURL); )?B-en\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); " W{rS4L  
httpConnection.setRequestProperty("User-Agent","NetFox"); v$x)$/]n  
String sProperty = "bytes="+nStartPos+"-"; ^_V0irv  
httpConnection.setRequestProperty("RANGE",sProperty); .I]v D#o  
Utility.log(sProperty); "'+C%  
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InputStream input = httpConnection.getInputStream(); y!
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//logResponseHead(httpConnection); zFipuG0
2  
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byte[] b = new byte[1024]; ]]`[tVaFr  
int nRead; Z,\(bW qF  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) N%q{CYF6  
{ =h=-&DSA  
nStartPos += fileAccessI.write(b,0,nRead); kB5y}v.3 S  
//if(nThreadID == 1) @MFEBc}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aO?KRn  
} QhAYCw2  
7@y}J5,  
[AFGh L+t3  
Utility.log("Thread " + nThreadID + " is over!"); +XX5;;IC  
bDownOver = true; d!Ws-kzE  
//nPos = fileAccessI.write (b,0,nRead); Yt:%)&50}-  
}  r3OtQ  
catch(Exception e){e.printStackTrace ();} `*yOc6i]  
} _Gb7n5p  
} ,1!Y!,xy  
Wnp[8IEU  
!B{(EL=g  
//打印回应的头信息 1cMdoQ  
public void logResponseHead(HttpURLConnection con)
hBcklI  
{ E5|GP  
for(int i=1;;i++) t1oTZ  
{ FEopNDy@y  
String header=con.getHeaderFieldKey(i); NU{eoqaT  
if(header!=null) qPUACuF'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); : 4lR`%  
Utility.log(header+" : "+con.getHeaderField(header)); 3BLHd<  
else t4~?m{
 
break; 2v4&'C  
} 5^l-3s?M  
} 2\O!vp>|-  
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public void splitterStop() sT<h+[2d  
{ |pU>^  
bStop = true; p&`I#
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} /Jc^XWf  
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} " ;8kKR  
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/*  s-&
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**FileAccess.java (tzAUrC  
*//文件访问(定位，写) 4 BNbS|?vV  
package NetFox; &#~U1: 0  
import java.io.*; u`-
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%)^0NQv  
n4"xVDL  
public class FileAccessI implements Serializable{ h4ghMBo%  
TC:t!:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (V/!0Lj  
RandomAccessFile oSavedFile; #0#
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long nPos; ashVV
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public FileAccessI() throws IOException F:0 E- z'  
{ (~b0-3s  
this("",0); jt9@aN.mJN  
} OQyZ'  
3A\Hiy!{F  
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public FileAccessI(String sName,long nPos) throws IOException I;P! 
 
{ $"=0{H.?  
oSavedFile = new RandomAccessFile(sName,"rw"); w%6 L"  
this.nPos = nPos; d+8|aS<A  
oSavedFile.seek(nPos); [t5Dd  
} L>57eF)7  
g^\>hjNX  
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public synchronized int write(byte[] b,int nStart,int nLen) 3}.OSt'=  
{ Y[;Z7p  
int n = -1; lgHzI(  
try{ . vea[  
oSavedFile.write(b,nStart,nLen); -#AO4xpI  
n = nLen; 3[m~6Ys  
} g
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catch(IOException e) K5+ONA<c  
{ 4&`d$K  
e.printStackTrace (); {?IUf~<  
} bGB5]%v,  

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).$kp
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return n; ]k.YG!$  
} p!K]cD  
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} 6~8dMy;w  
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/* F;Ubdxwwl  
**SiteInfoBean.java `
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*/ k)fLJ9R  
package NetFox; #}'sknvM}  
x^UAtKSy  
HR?a93  
public class SiteInfoBean { '494^1"io  
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:[  
'[[*(4a3  
private String sSiteURL; //Site's URL [8`^_i=#  
private String sFilePath; //Saved File's Path ery{>|k  
private String sFileName; //Saved File's Name #w)D ml  
private int nSplitter; //Count of Splited Downloading File ~NO'8Mr  
3:!5 ]  
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public SiteInfoBean() Vdf~rV  
{//nSplitter的缺省值为5 e= _7Q.cn  
//default value of nSplitter is 5 |\q@XCGei  
this("","","",5); 9 J~KM=p  
} x[YW 3nF  
4p`z%U~=u  
t-J\j"~%+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]B
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{ \MmKz^tO  
sSiteURL= sURL; p!cNn7{;  
sFilePath = sPath; TbhsOf!  
sFileName = sName; to'O;f">n  
this.nSplitter = nSpiltter; D?? \H\  
CK} _xq2b  
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} bRc~e@  
[Z+E_Lbz  
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public String getSSiteURL() Jd/XEs?<q  
{ K;(t@GL?  
return sSiteURL; J
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} dw< b}2  
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public void setSSiteURL(String value) BQ77n2(@  
{ 1BA5|  
sSiteURL = value; P;lDri  
} >]l7AZ:,  
Gv}~  
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public String getSFilePath() IgtTYxI  
{ J k FZd  
return sFilePath; aboA9pwH  
} ^Jn=a9Q6Z  
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V%!my[b  
public void setSFilePath(String value) +K*_=gHF.  
{ {FNq&)#`  
sFilePath = value; W q>qso  
} -VRKQNT  
$t42?Z=N&z  
eop7=!`-~~  
public String getSFileName() C2Af$7c  
{ Qx}hiv/  
return sFileName; X0gWTs  
} }h_= n>  
++M%PF [ {  
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public void setSFileName(String value) :j
ioF{,  
{ AoN|&o  
sFileName = value; ?$rHyI  
} 7e`h,e=  
dRnO5 7+{  
@ Yzj  
public int getNSplitter() BpZ17"\z  
{ @k,}>Tk  
return nSplitter; A**PGy.Ni  
} I=Xj;\b  
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public void setNSplitter(int nCount) 0w ] pDj  
{ gpzZs<ST  
nSplitter = nCount; SI@Yct]<g  
} !7fVO2m T  
} 9Kd:7@U  
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qz/d6-0"  
/* K yFR;.F-  
**Utility.java B< BS>(Nr>  
*/ 14;lB.$p  
package NetFox; DANndXQLH  
B(|dT66K  
23=SXA!  
public class Utility { ZpQ8KY$5  
?e+$?8l[3  
n"c3C)  
public Utility() &26H  
{ I &I q  
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} U/I+A|S[  
`h|>;u   
//线程睡眠 1$
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public static void sleep(int nSecond) X-=J7G`\h#  
{ 1(12`3  
try{ ;Q} H'Wg,  
Thread.sleep(nSecond); 4Gm(P~N  
} N:Zf4  
catch(Exception e) gR:21*&cz  
{ |Zrkk>GW:  
e.printStackTrace (); R~&i8n.  
} d8Kxtg Y  
} =C.WM*='  
=
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//日志 Um'r6ty  
public static void log(String sMsg) !4l\*L  
{ ``4lomz>  
System.err.println(sMsg); gC qQ~lWZ  
} Jf=$h20x  
o{&UT VyGs  
Jz6,2,LN  
public static void log(int sMsg) &k2nt  
{ FI$#x%A  
System.err.println(sMsg); N$SJK  
} 4C{3>BE  
} rv?d3QqIC  
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vz_ZXy9Z  
/* 8fwM)DKS  
**TestMethod.java \7Fkeo+  
*/ Z*r
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package NetFox; Ut xe  
-'OO6mU  
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public class TestMethod { h8MkfHH7{  
]XH}G9X^  
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public TestMethod() hj.Du+1  
{ ///xx/weblogic60b2_win.exe sR1 &2hB  
try{ br9`77J8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C8 b%r|^#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !bHM:!6^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $iblLZhj  
fileFetch.start(); nBVknyMFNF  
} !7K-Kqn  
catch(Exception e){e.printStackTrace ();} CF`fn6  
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} r2
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`(9B(&
t^,  
/B?hM&@z  
public static void main(String[] args) 6/#5TdJA  
{ mJ%r2$/*  
new TestMethod(); ]3E':JM@  
} j;k(AM<  
} \O7?!i  
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