http断点续传简单实现（java)

/*
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**SiteFileFetch.java Zl)|x%z  
*/ \?ZdUY  
package NetFox; JcP'+
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import java.io.*; Jz6PqU|=  
import java.net.*; `}bUf epMJ  
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public class SiteFileFetch extends Thread { = N#Ww
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SiteInfoBean siteInfoBean = null; //文件信息Bean &zR}jD>  
long[] nStartPos; //开始位置 VF-d^AGt  
long[] nEndPos; //结束位置 Am0$UeSZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *=8)]_=f  
long nFileLength; //文件长度 _:z~P<%s  
boolean bFirst = true; //是否第一次取文件 H_Yy.yi  
boolean bStop = false; //停止标志 :A$6Y*s\  
File tmpFile; //文件下载的临时信息 @P-7a`3*  
DataOutputStream output; //输出到文件的输出流 A28w/=e7  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） khR3[ju{^  
public SiteFileFetch(SiteInfoBean bean) throws IOException I'gnw~  
{ MG6Tk(3S  
siteInfoBean = bean; \yqiv"'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;Cwn1N9S  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gOkO8P6P8  
if(tmpFile.exists ()) WXM_H0K  
{ #df43_u  
bFirst = false; \=@}(<4  
read_nPos(); QqDF_
  
} -H \nFJ6+  
else H`
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{ L81"W`?  
nStartPos = new long[bean.getNSplitter()]; (#:Si~3  
nEndPos = new long[bean.getNSplitter()];
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} _YY)-H  
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} }XUHP%  
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public void run() zb<+x(0y"  
{ [H&m@*UO  
//获得文件长度 ; ^$RG
  
//分割文件 B}Qo8i7 z  
//实例FileSplitterFetch \8pbPo=x  
//启动FileSplitterFetch线程 g/E;Oc
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//等待子线程返回 >eXNw}_j  
try{ |LQmdgVr$  
if(bFirst) 9.R_=  
{ g (~&  
nFileLength = getFileSize(); M_e!s}F  
if(nFileLength == -1) ck}y-,>,[O  
{ b9U2afd  
System.err.println("File Length is not known!"); ql4T@r3l}3  
} c*h5lM'n6  
else if(nFileLength == -2) ,kP{3.#Q  
{ ^\!^#rO  
System.err.println("File is not access!"); RHxd6Gs"  
} 1~*_H_Q't  
else r}991O<  
{ sqy5r
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for(int i=0;i<nStartPos.length;i++) RPrk]<<1  
{ 3lJK[V{'#'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); aV ^2  
} 6Q
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for(int i=0;i<nEndPos.length-1;i++) O~D}&M@/R  
{ -&&mkK B!  
nEndPos = nStartPos[i+1]; !>+ 0/  
}  A=,
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nEndPos[nEndPos.length-1] = nFileLength; lRrOoON  
} [:o#d`^  
} 0QPipuP  
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//启动子线程 q\~7z1   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D Lu]d$G  
for(int i=0;i<nStartPos.length;i++) b"gYNGgX  
{ B
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >8,BC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <ZocMv9gM  
nStartPos,nEndPos,i); \CL`j  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h$k(|/+  
fileSplitterFetch.start(); T7,tJk,(  
} ^a(q7ZfY
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |9g*rO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MDlCU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >):b AfI  
nEndPos = " + nFileLength); R38 w!6{  
// fileSplitterFetch[nPos.length-1].start(); l})uYae/  
\!%3giD5!  
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//等待子线程结束 QCjmg5bf'7  
//int count = 0; CN >q`[!  
//是否结束while循环 %jkd}D  
boolean breakWhile = false; | zAey\  
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gt ?&!S^  
while(!bStop) T.xW|Iwx  
{ CzK X}  
write_nPos(); rF5<x3  
Utility.sleep(500); UeVF@rw  
breakWhile = true; 6"wY;E  
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for(int i=0;i<nStartPos.length;i++) g` Wr3  
{ rg $71Ir  
if(!fileSplitterFetch.bDownOver) {c$W-t):U|  
{  $%jV%k  
breakWhile = false; M_PL{  
break; d BJM?/  
} b w cPY  
} /r)d4=1E  
if(breakWhile) 86I".R$d  
break; > 4^U=T#  
xv)7-jlx  
!is8`8F8  
//count++; ZpwB"%e$  
//if(count>4) G1D(-X4ALZ  
// siteStop(); Um|:AT}`^  
} s2tEyR+gW  
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V9MA)If>  
System.err.println("文件下载结束！"); <uAqb Wu  
} T"2ye9a  
catch(Exception e){e.printStackTrace ();} 'r-a:8:t^  
} kAAz|dhL-  
h\yYg'CC  
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//获得文件长度 aWit^dp  
public long getFileSize() h;B'#$_  
{ DZ EA*E
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int nFileLength = -1; Sw0~6RZ  
try{ m.2  
URL url = new URL(siteInfoBean.getSSiteURL()); Y!SD^Ie7!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Pukq{/27  
httpConnection.setRequestProperty("User-Agent","NetFox"); c,+oH<bZZs  
`T mIrc  
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int responseCode=httpConnection.getResponseCode(); t!K|3>w  
if(responseCode>=400) tV<Au  
{ t!PFosFp  
processErrorCode(responseCode); 1e&`m~5K+  
return -2; //-2 represent access is error h[ tOY  
} 8`im4.~#%  
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*:_.cbo  
String sHeader; ]-0 &[@I4@  
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for(int i=1;;i++) l5aQDkp}  
{ =7$YBCuF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F[J;u/Z  
//Utility.log(in.readLine()); 7%o\O{,U
  
sHeader=httpConnection.getHeaderFieldKey(i); - @  
if(sHeader!=null) =EIsqk^*  
{ Hiw{1E:rW  
if(sHeader.equals("Content-Length")) OnD+/I  
{ ;ymUMQ%;/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h'N,oDB)  
break; ]o_ Ps|  
} ]A_)&`"Cb  
} z`/v}'d[X  
else lfCoL@$6D  
break; ;KnnAZJ  
} <8H`y(S  
} [jafPi(#g  
catch(IOException e){e.printStackTrace ();} c|I{U[(U  
catch(Exception e){e.printStackTrace ();} xOS4J+'s@  
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ost~<4~  
Utility.log(nFileLength); |vGz 1jLV  
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return nFileLength; p[W8XX  
} or(Z-8a_  
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(}}BZS&.  
//保存下载信息（文件指针位置） Ha;^U/0|  
private void write_nPos() 4$.4,4+  
{ 6W~F nJI  
try{ FzW(An&x2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aLP2p
]  
output.writeInt(nStartPos.length); ==c\* o  
for(int i=0;i<nStartPos.length;i++) l'$AmuGj  
{ ^g
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// output.writeLong(nPos); {y :/9  
output.writeLong(fileSplitterFetch.nStartPos); 7|H !(a'  
output.writeLong(fileSplitterFetch.nEndPos); 2&P'rmFm  
} fLPB *y6  
output.close(); 3:S Ex;d+  
} |3vQmd !2}  
catch(IOException e){e.printStackTrace ();} * \f(E#wa  
catch(Exception e){e.printStackTrace ();} ;@Ls"+
g  
} .O~)zMx  
(3W
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[ UQzCqV  
//读取保存的下载信息（文件指针位置） ?-*_v//g  
private void read_nPos() )=8X[<^i  
{ MTa.Ubs  
try{ _ 57m] ;&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); tz2`X V{  
int nCount = input.readInt(); ='YR;  
nStartPos = new long[nCount]; fNQ.FAK":  
nEndPos = new long[nCount]; fU$zG"a_  
for(int i=0;i<nStartPos.length;i++) xpUaFb  
{ HHT K{X+  
nStartPos = input.readLong(); rW!P~yk  
nEndPos = input.readLong(); \u:xDS
(  
} L{osh0  
input.close(); :fo%)_Jc!  
} +xB!T1pD  
catch(IOException e){e.printStackTrace ();} R$NH [Tz  
catch(Exception e){e.printStackTrace ();} QIGMP=!j  
} z]~B@9l  
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private void processErrorCode(int nErrorCode) ]"aC wr  
{ L1M]ya
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System.err.println("Error Code : " + nErrorCode); OyFBM>6gh  
} ^-mz!{  
=|=9\3po  
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//停止文件下载 8%2*RKj  
public void siteStop() /1t(e._  
{ v?5Xx{ym  
bStop = true; 0l{').!_  
for(int i=0;i<nStartPos.length;i++) 7w YSP&$  
fileSplitterFetch.splitterStop(); q4Qm:|-  
}hEBX:-  
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} j[9xF<I  
} IZniRd;  
//负责部分文件的抓取 %<:?{<~wH9  
**FileSplitterFetch.java [sbC6(z  
*/ :,6dW?mun6  
package NetFox;
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import java.io.*; M'Q{2%:>a  
import java.net.*; ?}lgwKBHl;  
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public class FileSplitterFetch extends Thread { ,RDxu7iT  
 E~jNUTq  
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String sURL; //File URL %TvunV7NQS  
long nStartPos; //File Snippet Start Position @D Qg1|m  
long nEndPos; //File Snippet End Position \snbU'lfP  
int nThreadID; //Thread's ID H>a3\M  
boolean bDownOver = false; //Downing is over VTy!<I  
boolean bStop = false; //Stop identical C KBLM2D  
FileAccessI fileAccessI = null; //File Access interface pu,/GBG_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i8+kc_8#d  
{ u3w `(3{<  
this.sURL = sURL; X Oc0j9Oa  
this.nStartPos = nStart; *!Vic#D%  
this.nEndPos = nEnd; A<QYW,:|  
nThreadID = id; )k- 7mwkZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 F;}?O==H;  
} `{<2{}2M  
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public void run() O=G2bdY{,  
{ v5RS<?o  
while(nStartPos < nEndPos && !bStop)
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{ Y:ZI9JK?  
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try{ )j]S;Mr  
URL url = new URL(sURL); 9v_gR52vh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z#3wMK~  
httpConnection.setRequestProperty("User-Agent","NetFox"); TJ ;4QL  
String sProperty = "bytes="+nStartPos+"-"; w(<; $9  
httpConnection.setRequestProperty("RANGE",sProperty); VsNqYFHes&  
Utility.log(sProperty); #}^
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InputStream input = httpConnection.getInputStream(); 9L*gxI>  
//logResponseHead(httpConnection); &:nWZ!D  
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byte[] b = new byte[1024]; j}X4#{jgC  
int nRead; ^-f5;B`\i  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x\3tSP7Vp  
{ _Oh;._PS  
nStartPos += fileAccessI.write(b,0,nRead); _|g(BK2}  
//if(nThreadID == 1) Xa Yx avq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H7H'0C  
} Gg{@]9  
p}}}~ l
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Utility.log("Thread " + nThreadID + " is over!"); *;1G+Q#  
bDownOver = true; #Jq@p_T"  
//nPos = fileAccessI.write (b,0,nRead); hUxpz:U*  
} cSnm\f  
catch(Exception e){e.printStackTrace ();} k9w<
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} =u
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} 6jO*rseC  
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//打印回应的头信息 {Ejv8UdA9  
public void logResponseHead(HttpURLConnection con) Z8}Zhe.  
{ ACU0  
for(int i=1;;i++) P zzX Ds6  
{ e-]k{_wm  
String header=con.getHeaderFieldKey(i); (b GiBsb  
if(header!=null) |rq~.cA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Sr,ZM1J
 
Utility.log(header+" : "+con.getHeaderField(header)); M+ ^]j  
else pr>K#@^  
break; 6<(HT#=
#  
} .[+8D
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} mRW(]OFIai  
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public void splitterStop()
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{ qF%wl  
bStop = true; &bRmr/D  
} ^8 AV#a  
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} W7O%.xP  
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\
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/* XqyfeY5t  
**FileAccess.java _U.8\J2  
*//文件访问(定位，写) 23U9+  
package NetFox; &+J5GHt@  
import java.io.*; mucY+k1>g  
/:z}WAW  
0Dc$nL?TqX  
public class FileAccessI implements Serializable{ VS%8f.7ep  
l9qq;hhGP,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 VrQw;-rQ  
RandomAccessFile oSavedFile; e1[kgp   
long nPos; lh(A=hn"n  
1&i!92:E  
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public FileAccessI() throws IOException nm*1JA.:  
{ OC7:Dp4  
this("",0); }]=b%CPJh+  
} ZZ]/9oiF%  
zblh_6  
p!hewtb5  
public FileAccessI(String sName,long nPos) throws IOException -x:Wp*,  
{ r\'3q'7p  
oSavedFile = new RandomAccessFile(sName,"rw"); oT\B-lx  
this.nPos = nPos; u17Da9@;  
oSavedFile.seek(nPos); pZlBpGQf  
} zc*qmb  
(J\D"4q  
wrK$ZO]  
public synchronized int write(byte[] b,int nStart,int nLen) [<1i[\^  
{ dK|MQ <  
int n = -1; r1}7Q7-z  
try{ Hu1w/PLq  
oSavedFile.write(b,nStart,nLen); /n@_Ihx  
n = nLen; rYJt;/RtR}  
} Z!wDh_  
catch(IOException e) H+zQz8zMC  
{ E36<Wog  
e.printStackTrace (); Y
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} X H{5E4P  
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return n; nFw&vR/q  
} [EB2o.EsO  
<2}"Y(zwKl  
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} [GU!],Y  
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/* .zBSjh_=H  
**SiteInfoBean.java #uuwzE*M_  
*/ cMC1|3
 
package NetFox; + #S]uC  
d!Y,i!l!  
<%qbU-  
public class SiteInfoBean { 6CY_8/:zL  
zT!JHG
 
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private String sSiteURL; //Site's URL hh:0m\@<  
private String sFilePath; //Saved File's Path G]QD6b9~  
private String sFileName; //Saved File's Name >'Y]C\  
private int nSplitter; //Count of Splited Downloading File ;2#7"a^  
Z~T- *1V  
.6e5w1r63  
public SiteInfoBean() n?kU  
{//nSplitter的缺省值为5 He">kJx  
//default value of nSplitter is 5 1G{$ B^ f  
this("","","",5); Pg*ZQE[ME8  
} rb`C:#j{J  
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oE-i`;\8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?>4^e:  
{ L|!9%X0.  
sSiteURL= sURL; al#yc  
sFilePath = sPath; K'1rS[^>R  
sFileName = sName; PuUqWW'^  
this.nSplitter = nSpiltter; ;M@/AAZ  
KZ/}Iy>As  
I#uJdV|x  
} 7Py8!  
ew}C*4qH  
G>*s+  
public String getSSiteURL() Er~5\9,/<]  
{ BuK82  
return sSiteURL; |`:Uww+3  
} 2&Wc4,O!i  
lFI"U^xC  
?\ho9nyK  
public void setSSiteURL(String value) E*rDwTd  
{ 2\EMtR>.M'  
sSiteURL = value; 2E=E!Zwt_  
} h2h$UZIv  
N:"E%:wSbi  
G}}oeS  
public String getSFilePath() Q:=s99  
{ RFQa9Rxk  
return sFilePath; Dve5Ml-  
} ?A,gDk/#  
<<4G GO  
`|v0@-'$  
public void setSFilePath(String value) o8Q(,P  
{ GW.s\8w  
sFilePath = value; n#Z6d`  
} \*d@_oQ$  
Ha4?I$'$  
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public String getSFileName() GD~3RnGQ{
 
{ {*>$LlL  
return sFileName; pEhWgCL  
} qXP)R/~OZ  
Xo{Ce%L  
|MTgKEsn  
public void setSFileName(String value) <NT/+>:2  
{ J"FKd3~:E  
sFileName = value; _RY<-B   
} KJcdX9x  
>nvreis  
w?<:`  
public int getNSplitter() o.}^6.h"  
{ -"!V&M  
return nSplitter; LF*3Iw|v  
} n1buE1r?  
=eTI@pN`  
sOU_j4M{  
public void setNSplitter(int nCount) hiU_r="*ox  
{ /i DS#l\0  
nSplitter = nCount; `d3S0N6@  
} e0>@Yp[Kd  
} 6sB!m|zm]:  
"%A[%7LY  
|mY<TWoX  
/* ,<pql!B-  
**Utility.java a,&Kvh  
*/ !i}G>*XH,  
package NetFox; |W*f
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public class Utility { t'm]E2/  
Z4hP  
!jYV,:'  
public Utility() D|9B1>A,m  
{ NF&\<2kX  
a
7#Eyw^H{  
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} ,ISq7*%F  
{} vl^b  
//线程睡眠 {fIH9+v  
public static void sleep(int nSecond) =bv8W <#  
{ EY2s${26%  
try{ jGt'S{  
Thread.sleep(nSecond); _;LH
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}  tEP^w  
catch(Exception e) r OB\u|Pg  
{ .=^h@C*   
e.printStackTrace (); z^B!-FcIz>  
} QfwGf,0p  
} &Lq @af#  
:nZ*x=aq  
//日志 3t%uUkXl  
public static void log(String sMsg) }$AC0  
{ O8dD
oP\F2  
System.err.println(sMsg); lD C74g  
} /=7|FtB`  
eTrGFe!8w  
xZ9y*Gv\=  
public static void log(int sMsg) *+@/:$|U  
{ g3x192f  
System.err.println(sMsg); DO( /,A<{8  
} U35}0NT _  
} @ju-cv+  
.v;2Q7X  
p}(w"?2  
/* *?KQ\ Y  
**TestMethod.java sBSBDjk[  
*/ ={feN L  
package NetFox; F1%' zsv  
ih~c(&n0  
bWMM[pnL  
public class TestMethod { ao7|8[  
\=5CNe  
:;??!V  
public TestMethod() OpH9sBnA  
{ ///xx/weblogic60b2_win.exe `yC R.3+  
try{ RKBjrSZg8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YnI   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
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SiteFileFetch fileFetch = new SiteFileFetch(bean); 9sT?"(=  
fileFetch.start(); Wm3H6o*  
} 1p8E!c{}j
 
catch(Exception e){e.printStackTrace ();} 5'z&kl0"S  

/!%P7F  
K7_)!=DcX  
} C %EQ9Iq6r  
W}.4$f>  
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public static void main(String[] args) S?8q.59  
{ ,#"AW
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new TestMethod(); !J:DBtGT  
} ?T4%"0  
} {b#c0>.8-  
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