http断点续传简单实现（java)

/* n0i&P
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**SiteFileFetch.java =,]J"n8|v  
*/ g4$%)0x%  
package NetFox; Zz&i0r  
import java.io.*; A0X0t  
import java.net.*; EhUy7b,1_  
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n*6s]iG V  
public class SiteFileFetch extends Thread { `U1%d7[vY  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4K;j:ZJ"x  
long[] nStartPos; //开始位置 ry]7$MQyV  
long[] nEndPos; //结束位置 v#+w<gRq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Y-c~"#  
long nFileLength; //文件长度 ?-84_i  
boolean bFirst = true; //是否第一次取文件 XP^6*}H.*  
boolean bStop = false; //停止标志 7~

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File tmpFile; //文件下载的临时信息 1=a}{)0h  
DataOutputStream output; //输出到文件的输出流 k"7eHSy,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .-Lqo=o\  
public SiteFileFetch(SiteInfoBean bean) throws IOException jgo@~,5R  
{ @!'H'GvA  
siteInfoBean = bean; zB$6e!fc  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D5m\u$~V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); N]<gHGj}  
if(tmpFile.exists ()) GDB>!ukg  
{ h*9o_  
bFirst = false; .>'Z9.Xnk  
read_nPos(); 9h(hx7]  
} dJ^`9W  
else G0Eq}MyF  
{ /a|NGh%  
nStartPos = new long[bean.getNSplitter()]; 7 f*_  
nEndPos = new long[bean.getNSplitter()]; e`Yns
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} 8)!;[G|  
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} NGY I%:  
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public void run() )\;r V';  
{ [E~TYk;  
//获得文件长度 E}=,"i  
//分割文件 8vw]u_e  
//实例FileSplitterFetch Xt84Evo  
//启动FileSplitterFetch线程 4"{wga~%/  
//等待子线程返回 n_Y]iAoc`  
try{ (Qm;]?/  
if(bFirst) U
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{ k>CtWV5B  
nFileLength = getFileSize(); Z :+#3.4$3  
if(nFileLength == -1) 8!SiTOzR?  
{ __iyBaX  
System.err.println("File Length is not known!"); \^4$}@*]  
} (FYJ^o  
else if(nFileLength == -2) <Y2!c,"  
{ fLoVcl  
System.err.println("File is not access!"); rfi`Bp  
} FO=1P7  
else m_ m@>}ud  
{ ;/T-rVND  
for(int i=0;i<nStartPos.length;i++) ,-Nk
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{ <R>ZG"m{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); BD-=y  
} K:@=W1  
for(int i=0;i<nEndPos.length-1;i++) I}IW!K  
{ 2QRn c"  
nEndPos = nStartPos[i+1]; |=T<WU1$  
} q*nz4QTOE  
nEndPos[nEndPos.length-1] = nFileLength; W@dY:N}  
} UJ$:5*S=u  
} T6roz  
,P@-DDJ  
*$C[![  
//启动子线程 yWtr,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u(Sz$eV  
for(int i=0;i<nStartPos.length;i++) kG$8E  
{ =+S3S{\CK  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .boizW1+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), o~&!M_ED  
nStartPos,nEndPos,i); 3&fFIab9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /*^|5>-`i1  
fileSplitterFetch.start(); Z;\"pP:  
} 6ya87H'e@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <@2# VG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); f;H#TSJ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;w(1Ydo  
nEndPos = " + nFileLength); D])YP0|}  
// fileSplitterFetch[nPos.length-1].start(); >?eTbtP  
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//等待子线程结束 GPLt<K!<#  
//int count = 0; h)^A3;2F  
//是否结束while循环 DF|s,J`98  
boolean breakWhile = false; zN)\2  
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while(!bStop) X\2hKUkT  
{ ko2j|*D6@~  
write_nPos(); ]=VS~azZ5  
Utility.sleep(500); .4FcZJvy  
breakWhile = true; XuoEAu8]  
|;m`874  
0DVZRB  
for(int i=0;i<nStartPos.length;i++)  &Z!K]OSY  
{ H&Y{jqua  
if(!fileSplitterFetch.bDownOver) Y*cJ4hQ  
{ >-5Gt  
breakWhile = false; SuH.lCF-g  
break; ?VP!1O=J  
} / &D$kxz  
} \R\@t]>Y  
if(breakWhile) L2.`1Aag  
break; .`>
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q,+kPhHEgy  
(e3Gs+;  
//count++; TTZxkK  
//if(count>4) F*JvpI[7n  
// siteStop(); (2bZ]  
} !aw#',r8m  
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System.err.println("文件下载结束！"); apD=>
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} o?mXxL)  
catch(Exception e){e.printStackTrace ();} N46$EsO!h  
} vd7N&c9  
Gh[`q7B Q  
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//获得文件长度 ;i9<y8Dha  
public long getFileSize()  Vm;Qw  
{ 6$fnQcpJ  
int nFileLength = -1; +i@yZfT  
try{ 5Sjr6l3Vq8  
URL url = new URL(siteInfoBean.getSSiteURL()); sC5uA .?>9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4!~ .6cp3  
httpConnection.setRequestProperty("User-Agent","NetFox"); Qj<{oZp&  
YG 5Z8@kH  
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int responseCode=httpConnection.getResponseCode(); _p J_V>l  
if(responseCode>=400) ca/o#9:N`:  
{ =PFR{=F  
processErrorCode(responseCode); nOal7BNN  
return -2; //-2 represent access is error b?]ly(  
} yvooM'R  
"vOfAo]`  
5u|=;Hz*)  
String sHeader; u@Cf*VPK  
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for(int i=1;;i++) P A6KX5  
{ CI!Eq&D,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N`<4:v[P  
//Utility.log(in.readLine()); Vv
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sHeader=httpConnection.getHeaderFieldKey(i); 33<fN:J]f  
if(sHeader!=null) `!omzE*bk5  
{ {nQ)4.e6  
if(sHeader.equals("Content-Length")) S}w.#tyEn  
{ 0i*'N ch#i  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); w~$c= JO#  
break; S@}B:}2  
} rI<nUy P?  
} ?wLdW1&PpX  
else :Dk@?o@2;C  
break; Y0PGT5].@'  
} E +Ujpd  
} OS"{"P  
catch(IOException e){e.printStackTrace ();} ^s2m\Q(  
catch(Exception e){e.printStackTrace ();} _[TH@fO6:  
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Utility.log(nFileLength); 1J-Qh<Q   
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return nFileLength; ," C[Qg(  
} y^X\^Kq  
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//保存下载信息（文件指针位置） -OrY{^F  
private void write_nPos() 0\cnc^Z  
{ 1c)\  
try{ %Ui{=920  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %wt2F-u  
output.writeInt(nStartPos.length); i5 L:L  
for(int i=0;i<nStartPos.length;i++) Hz]4AS  
{ *bCi2mbm@  
// output.writeLong(nPos); a1g6}ym\  
output.writeLong(fileSplitterFetch.nStartPos); VelB-vy&  
output.writeLong(fileSplitterFetch.nEndPos); jcEs10y  
} &\1'1`N1  
output.close(); \-Iny=$  
} 0~+NB-L}  
catch(IOException e){e.printStackTrace ();} iY ^{wi~?  
catch(Exception e){e.printStackTrace ();} 1m>^{u  
} |oe!P}u  
?{ B[
^  
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//读取保存的下载信息（文件指针位置） g>~cs_N@  
private void read_nPos() (VYR
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{ 83KfM!w  
try{ N
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ptV4s=G2  
int nCount = input.readInt(); _{6,.TN  
nStartPos = new long[nCount]; U@.u-)oX  
nEndPos = new long[nCount]; ;RWW+x8IB  
for(int i=0;i<nStartPos.length;i++) zBk_-'z  
{ .vv5t  
nStartPos = input.readLong(); y)3~]h\a  
nEndPos = input.readLong(); 4? m/*VV  
} 5-8]N>/b!  
input.close(); `*e4m  
} L
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catch(IOException e){e.printStackTrace ();} 6P;o 6s  
catch(Exception e){e.printStackTrace ();} -6rf( ER  
} 4 ,p#:!  
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private void processErrorCode(int nErrorCode) N9i}p^F<_  
{ 5%<TF.;-J  
System.err.println("Error Code : " + nErrorCode); e7@li<3>d  
} %{R_^Y8t  
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3<c*v/L{C\  
//停止文件下载 [AXsnpa/C  
public void siteStop() 6xQ"bFm  
{ sA/,+aM  
bStop = true; B/jrYT$;m  
for(int i=0;i<nStartPos.length;i++) Ln ~4mN^  
fileSplitterFetch.splitterStop(); 0TTIaa$  
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} hzaLx8L  
} 9;=q=O/  
//负责部分文件的抓取 Ur^YG4(  
**FileSplitterFetch.java bt;lq!g  
*/ fd4;mc1T  
package NetFox; /@&(P#h  
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import java.io.*; I+0c8T(:  
import java.net.*; mT96]V\  
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B ,V(LTE  
public class FileSplitterFetch extends Thread { +.w[6  
8)N0S% B  
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String sURL; //File URL '.pgXsC:=?  
long nStartPos; //File Snippet Start Position D899gGe  
long nEndPos; //File Snippet End Position KzV.+f  
int nThreadID; //Thread's ID FyCBNtCv  
boolean bDownOver = false; //Downing is over e\`wlaP,  
boolean bStop = false; //Stop identical [ L   
FileAccessI fileAccessI = null; //File Access interface p` $fTgm  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException St
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{ !?jK1{E3  
this.sURL = sURL; 21U&Ww  
this.nStartPos = nStart; >yX/+p_  
this.nEndPos = nEnd; -:MmSeG7gO  
nThreadID = id; $u:<x
  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $nj\\,(g  
} jQ6Xr&}  
>wA+[81[  
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public void run() -(!uC+BZX  
{ 4bnt=5]  
while(nStartPos < nEndPos && !bStop) *t^eNUA  
{ @9aGz6k+  
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try{ |7y6 pz  
URL url = new URL(sURL); L${m/@9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :WVSJ,. !  
httpConnection.setRequestProperty("User-Agent","NetFox"); Uls+n@\!  
String sProperty = "bytes="+nStartPos+"-"; DE%fF,Hk3  
httpConnection.setRequestProperty("RANGE",sProperty); VrVDm*AGQ  
Utility.log(sProperty); w^3|(
F  
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6.[)`iF+#  
InputStream input = httpConnection.getInputStream(); ?H`j>]%&  
//logResponseHead(httpConnection); =LOk
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byte[] b = new byte[1024]; +s ULo  
int nRead; $%Z3;:<Uf-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *#zS^b n  
{ m~;B:LN<  
nStartPos += fileAccessI.write(b,0,nRead); CI^[I\$&  
//if(nThreadID == 1) }w#F6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h(nj,X+  
} /HZv  
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n&$/Q$d&  
Utility.log("Thread " + nThreadID + " is over!"); Bhe{L?}0  
bDownOver = true; fH[Wkif  
//nPos = fileAccessI.write (b,0,nRead); )9B:Y;>)  
} FNC[59  
catch(Exception e){e.printStackTrace ();} #ra*f~G  
} +Juh:1H  
} 6|5H=*)DH  
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//打印回应的头信息 -G-3q
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public void logResponseHead(HttpURLConnection con) BKay*!'PX  
{ ~ltg  
for(int i=1;;i++) `]jqQr97  
{ o5SQ1;`   
String header=con.getHeaderFieldKey(i); myIe_k,F  
if(header!=null) xz8G}Ku  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); FIS "Z(  
Utility.log(header+" : "+con.getHeaderField(header)); l[oe*aYN7  
else JGis"e  
break; s9i|mVtm8  
} >g]ON9CGH  
} >La><.z~  
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public void splitterStop() >I^9:Q  
{ b
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bStop = true; >?I/;R.-  
} 5$%XvM  
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} :RiF3h(  
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/* <^c3}  
**FileAccess.java lL0M^Nv  
*//文件访问(定位，写) m(_9<bc>  
package NetFox; Us=eq "eu  
import java.io.*; `eR 7H>I  
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($8t%jVWJJ  
public class FileAccessI implements Serializable{ {[W(a<%bXm  
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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 C6]OAUXy:F  
RandomAccessFile oSavedFile; $gvr -~  
long nPos; ?:uNN  
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public FileAccessI() throws IOException )R &,'`\  
{ :G=FiC  
this("",0); t7*#[x)a  
} ^~1<f1
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public FileAccessI(String sName,long nPos) throws IOException WbcS: !0  
{ "r$/  
oSavedFile = new RandomAccessFile(sName,"rw"); cbYK5fj"T  
this.nPos = nPos; 5JSrrpGr
 
oSavedFile.seek(nPos); >bIF>9T  
} i=#F)AD^5#  
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1m)M;^_  
public synchronized int write(byte[] b,int nStart,int nLen) [>Fm[5x
 
{ _ck[&Q  
int n = -1; xaW{I7FfG  
try{ i=rH7k  
oSavedFile.write(b,nStart,nLen); .<YcSG  
n = nLen; 8@eOTzm  
} L'E^c,-x~  
catch(IOException e) fYX<d%?7  
{ eV2mMSY  
e.printStackTrace (); =w%Oa<  
} ej^3YNh&  
efOjTA%  
k\aK?(.RC7  
return n; Ia4)uV8  
} #fDs[  
*C2R`gpBI  
/X#z*GX  
} \TbVS8e^  
)(TAT<  
G;1?<3
 
/* uQ3[Jz`y  
**SiteInfoBean.java orfp>B) 0  
*/ H"Dn]$Q\Z  
package NetFox; PJ\0JR7a  
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public class SiteInfoBean { :]II-$/8  
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private String sSiteURL; //Site's URL @PSL
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private String sFilePath; //Saved File's Path $kPHxD!"  
private String sFileName; //Saved File's Name ^3~e/PKM  
private int nSplitter; //Count of Splited Downloading File ^?GmrHC)  
y7lWeBnC  
[TTSA2  
public SiteInfoBean() a`c:`v2o  
{//nSplitter的缺省值为5 $B .Qc!m  
//default value of nSplitter is 5 |J>WC}g@n  
this("","","",5); s V  }+eU  
} =RKSag&  
f.xA_Y>  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) E6A/SVp  
{ ;['a  
sSiteURL= sURL; MesRa(  
sFilePath = sPath; o\=n4;S  
sFileName = sName; HdX2
YPYn;  
this.nSplitter = nSpiltter; 8%:]W^  
))T>jh  


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} $x
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public String getSSiteURL() {/8
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{ {
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return sSiteURL; I 3$dVls}  
} TO#Pz.)>B6  
.~D>5 JnEk  
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public void setSSiteURL(String value) I4c!m_sr  
{ <L0#O(L  
sSiteURL = value; r4XH =  
} G| m4m.  
5iX! lAFJ  
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public String getSFilePath() 1vevEa$  
{ ULqoCd%bK  
return sFilePath; =xN= #  
} {2KFD\i\  
%D=]ZV](  
Dr#c)P~Wd  
public void setSFilePath(String value) L}k/9F.5  
{ K_&MoyJJ9f  
sFilePath = value; 9S7A!AKE  
} 3Ofc\  
qUJ aeQ  
p( LZ)7/  
public String getSFileName() aX6}6zubr  
{ Y]g?2N=E  
return sFileName; G4-z3e,crr  
} ,xi({{L*  
AC- )BM';  
\XzM^K3  
public void setSFileName(String value) ~$,qgf  
{ ,<Kx{+ [h  
sFileName = value; j<yiNHC  
} P 7D!6q  
F7}-!  
_e<o7Y@_  
public int getNSplitter() T6BFX0$  
{ A#y@`}]!'  
return nSplitter; r,(Mu  
} 8p^B hd  
{]N3f[w  

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public void setNSplitter(int nCount) ^A_;#vK  
{ {8RFK4! V@  
nSplitter = nCount;
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} g_.^O$}  
} m_NCx]#e   
8?FueAM'  
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/* ]$iqa"{  
**Utility.java 3lxc4@Zmd  
*/ L"+
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package NetFox; [:EvTY  
]ZoPQUS?  
 $)~   
public class Utility { ef"?|sn  
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public Utility() ?}P5p^6  
{ 3251Vq %  
1R%1h9I4'  
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} .?W5{U  
@z`@f"l  
//线程睡眠 JK_OZ  
public static void sleep(int nSecond) ))h6~1`  
{ dFXc/VH')  
try{ $7Jo8^RE  
Thread.sleep(nSecond); }:Z9Vc ZP`  
} N_C;&hJN$w  
catch(Exception e) 9)dfL?x8V{  
{ $%k1fa C  
e.printStackTrace (); $4=
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} AONDx3[   
} 2'0K WYM  
uKr1Z2  
//日志 |AZ
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public static void log(String sMsg) mh/n.*E7  
{ 4Ft1@  
System.err.println(sMsg);  Ukz;0q  
} u'~;Y.@i'  
5`+5{p  
~%k?L4%  
public static void log(int sMsg) ?uLeFD  
{ uzr\
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System.err.println(sMsg); k=ytuV\  
} o2H1N~e#c  
} G@ \Pi#1  
32)tJ|m  
J4$! 68  
/* .^(/n9|o-  
**TestMethod.java +C]&2zc.  
*/ j{++6<tr  
package NetFox; ?X$,fQ#F|  
giY80!GX  
}ut]\]b  
public class TestMethod { <U Zd;e@  
7L5P%zLtB  
8T[ 6J{|C  
public TestMethod() YNdrW
Bf)  
{ ///xx/weblogic60b2_win.exe uzOYVN$t  
try{ Aj>[z8!,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qQ[b VD\*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3Hi+Z}8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ],etZ%z&  
fileFetch.start(); >`RRP}u=u  
} yBpk$  
catch(Exception e){e.printStackTrace ();} eU+ {*YJg  
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} F0Jx(  
ChrY"  
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public static void main(String[] args) KxGX\   
{ {2d_"lHBt  
new TestMethod(); $
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} &n2e  
} "Y:/= Gx  
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