http断点续传简单实现（java)

/* ^EELaG  
**SiteFileFetch.java 6e,xDr  
*/ .zg8i_  
package NetFox; \OILWQ[/  
import java.io.*; asJ!NvVG'  
import java.net.*; oF]cTAqhC.  
|re}6#TgcT  
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public class SiteFileFetch extends Thread { i;/xK
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SiteInfoBean siteInfoBean = null; //文件信息Bean wh6yPVVF/  
long[] nStartPos; //开始位置 Q=mI9  
long[] nEndPos; //结束位置 oA] KE"T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `x
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long nFileLength; //文件长度 xu5ia|gYz7  
boolean bFirst = true; //是否第一次取文件 j/`94'Y  
boolean bStop = false; //停止标志 k%s_0 @  
File tmpFile; //文件下载的临时信息 a"N4~?US  
DataOutputStream output; //输出到文件的输出流 Y;4!i?el  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） r;BT,jiX  
public SiteFileFetch(SiteInfoBean bean) throws IOException +mj*o(  
{ az0<5Bq)  
siteInfoBean = bean; FBx_c;)9Z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /1N6X.Zb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); uvDzKMw~R  
if(tmpFile.exists ()) &QRE"_g  
{ Q;11N7+  
bFirst = false; c'uhK8|  
read_nPos(); Hy.AyU|L  
} ho8`sh>N  
else T>TWU:  
{ ca i<,3H  
nStartPos = new long[bean.getNSplitter()]; K 0gI):  
nEndPos = new long[bean.getNSplitter()]; W1fW}0   
} ~5Pb&+<$  
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} dr)YzOvba  
**9x?s  
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public void run() ^;!0j9"*:  
{ $mf u:tbP  
//获得文件长度 -;f*VM.a  
//分割文件 FZjHw_pP  
//实例FileSplitterFetch *e
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//启动FileSplitterFetch线程 [Wd-Zn%  
//等待子线程返回 XO#/Fv!  
try{ rX_@Ihv'  
if(bFirst) !!@A8~H  
{ valtev0<  
nFileLength = getFileSize(); XL#[%X9  
if(nFileLength == -1) {{V8;y  
{ #^m0aB7r  
System.err.println("File Length is not known!"); =qN2Xg/  
} D\IjyZ-O  
else if(nFileLength == -2) SJD@&m%?[  
{ ^,m< 9  
System.err.println("File is not access!"); P96pm6H_;  
}
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else zvABU+{jD  
{ BA\/
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for(int i=0;i<nStartPos.length;i++) u]}s)SmDk  
{ l/;X?g5+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :0Z^uuk`gq  
} ?X@fKAj  
for(int i=0;i<nEndPos.length-1;i++) (c0A.L)  
{ zJe#m|Z  
nEndPos = nStartPos[i+1]; f{SB1M   
} @`\VBW  
nEndPos[nEndPos.length-1] = nFileLength; (&/2\0QV  
} }VDqj}is  
} wFG3KzEq ~  
*s@Qtgu  
U qG .:@T  
//启动子线程 V_plq6z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /cc\fw1+  
for(int i=0;i<nStartPos.length;i++) o7IxJCL=Q  
{  hi
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [+O"
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), GfM;saTz{  
nStartPos,nEndPos,i); j ";2o(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (sVi\R  
fileSplitterFetch.start(); nUkaz*4qU  
} f~}H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !i=nSqW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [M+f-kl  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aF03a-qw<  
nEndPos = " + nFileLength); cuOvN"nuNj  
// fileSplitterFetch[nPos.length-1].start(); %Uz(Vd
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=8U&[F  
R<B7K?SxV~  
//等待子线程结束 7G
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//int count = 0;
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//是否结束while循环 ^eW}XRI  
boolean breakWhile = false; J\e+}{  
JN7k2]{  
!^Q.VYY  
while(!bStop) @&[T _l  
{ @A)R_p  
write_nPos(); +V&{*f)  
Utility.sleep(500); o)'y.-@Q  
breakWhile = true; )BRKZQN  
{BKl`1z  
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for(int i=0;i<nStartPos.length;i++) ca+[0w@S  
{ uZ;D!2Q a  
if(!fileSplitterFetch.bDownOver) z=$jGL  
{ 7FRmx4(!  
breakWhile = false; II
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break; ;sHN/eF  
} >>[G1  
} qKJSj   
if(breakWhile) Y!;|ld  
break; |!y A@y?  
#r3l[bKK  
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//count++; pmX#E  
//if(count>4) 9cJH"  
// siteStop(); ? w^-  
}  &y<ZE  
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System.err.println("文件下载结束！"); "
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} o/ui)U_  
catch(Exception e){e.printStackTrace ();} Y#g4$"G9  
} \W%UZs  
id$Ul?z8  
'=l[;Q^Q  
//获得文件长度 <})'Y~i  
public long getFileSize() 7 [g/TB  
{ P6MRd/y |  
int nFileLength = -1; gzeQ|m2]  
try{ >MPr=W%E  
URL url = new URL(siteInfoBean.getSSiteURL()); L<fvKmo(fw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JgHM?AWg|  
httpConnection.setRequestProperty("User-Agent","NetFox"); `U2DkY&n  
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int responseCode=httpConnection.getResponseCode(); KoS*0U<g6  
if(responseCode>=400) [d* ~@P  
{ _v* nlc  
processErrorCode(responseCode);
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return -2; //-2 represent access is error 8/K!SpM*d  
} [CAR[ g&  
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String sHeader; {W##^
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^  :F.  
for(int i=1;;i++) S(7ro]U9  
{ . BiCBp<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ux+Q  
//Utility.log(in.readLine()); I2H6y"pN  
sHeader=httpConnection.getHeaderFieldKey(i); ncx(pp  
if(sHeader!=null) O iFS}p  
{ =~+DUMBT  
if(sHeader.equals("Content-Length")) HOBP`lf  
{ hS9;k9w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9aJ%`i  
break; 8iekEG$H  
} 3"{.37Q  
} ~xoF6CF  
else 77Bgl4P  
break; pFJB'=c  
} k#5}\w!  
} Oez>X=Xf  
catch(IOException e){e.printStackTrace ();} cm[c
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catch(Exception e){e.printStackTrace ();} 2ZQ}7`Y  
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Utility.log(nFileLength); aj}(E+  
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return nFileLength; +b3^.wkq  
} ~.!c~fke  
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xai4pF-?  
//保存下载信息（文件指针位置） 2W$cFC  
private void write_nPos() TXZv2P9  
{ K5"#~\D  
try{ )*:`':_a  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Dwl3Cj  
output.writeInt(nStartPos.length); n-TQ*&h]3S  
for(int i=0;i<nStartPos.length;i++) ;.bm6(;  
{ WMj}kq)SY)  
// output.writeLong(nPos); CSCN['x  
output.writeLong(fileSplitterFetch.nStartPos); n>'Kp T9|  
output.writeLong(fileSplitterFetch.nEndPos); <G*nDFWf  
} 4WB-Ec  
output.close(); AdWq Q  
} b pv=%  
catch(IOException e){e.printStackTrace ();} m
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catch(Exception e){e.printStackTrace ();} ~i.k$XGA  
} $2%f 8&  
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//读取保存的下载信息（文件指针位置） lq"f[-8a2q  
private void read_nPos() U#1bp}y  
{ 0T>H)c6:\  
try{ 72veLB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); x1ztfJd  
int nCount = input.readInt(); F!.E5<&7=  
nStartPos = new long[nCount]; |$7vI&m  
nEndPos = new long[nCount]; CX m+)a-L  
for(int i=0;i<nStartPos.length;i++) 5cWw7V<m  
{ =v*.p=
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nStartPos = input.readLong(); PH{_,X  
nEndPos = input.readLong(); rL5z]RY  
} t5lO'Ll*Q]  
input.close(); C^)
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} (os$B  
catch(IOException e){e.printStackTrace ();} zuJtpMn  
catch(Exception e){e.printStackTrace ();} OnWx#84  
} w4LScvBg  
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private void processErrorCode(int nErrorCode) 5 Qoew9rA  
{ !u]1dxa  
System.err.println("Error Code : " + nErrorCode); NuU9~gSQ  
} X(7qZ P~  
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21(p|`X  
//停止文件下载 sFBneBub  
public void siteStop() &[hLzlrg  
{ vp(;W,ba:|  
bStop = true; =LTmr
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for(int i=0;i<nStartPos.length;i++) *kIc9}  
fileSplitterFetch.splitterStop(); +,2Jzl'-  
$
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} 0KD]j8^  
} eX_D/25 $  
//负责部分文件的抓取 P+)DsZ0ig  
**FileSplitterFetch.java
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*/ @JW@-9/  
package NetFox; 4ikdM/  
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?3O9eZY@  
import java.io.*; C4}*)a  
import java.net.*; YSaJeU>@  
(|d34DOJ  
{vo +gRYYv  
public class FileSplitterFetch extends Thread { U?!>Nd  
O 1oxZj <  
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String sURL; //File URL F_bF  
long nStartPos; //File Snippet Start Position apk4j\i?5  
long nEndPos; //File Snippet End Position H}LS??P  
int nThreadID; //Thread's ID \a+(=s(;  
boolean bDownOver = false; //Downing is over +D1d=4  
boolean bStop = false; //Stop identical 7n90f2"m  
FileAccessI fileAccessI = null; //File Access interface fo4.JyBk  
XO <y+  
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)}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException phE &7*!Q  
{ 2r%lA\,h$  
this.sURL = sURL; /CTc7.OYt  
this.nStartPos = nStart; vLxQ *50v$  
this.nEndPos = nEnd; r",]Voibd  
nThreadID = id; c/5W4_J  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Z`&4SH=j  
} X w.p  
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public void run() <A9y9|>o  
{ Jdy=_88MD  
while(nStartPos < nEndPos && !bStop) %okzOKKX  
{ ,/O[=9l36R  
v2,%K`pAU  
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try{ `nO71mo  
URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .ZMW>U>  
httpConnection.setRequestProperty("User-Agent","NetFox"); fw;rbP!  
String sProperty = "bytes="+nStartPos+"-"; =H<0o?8?c  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty);  8L*GE  
?`[NFqv_]  
~}ET?Q7t  
InputStream input = httpConnection.getInputStream(); .qA{xbu  
//logResponseHead(httpConnection); 1&:@  
P_u|-~|\  
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byte[] b = new byte[1024]; 7E!7"2e a  
int nRead; O@iu aeEW  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) VzJ5.mRQ  
{ U4G}DCU  
nStartPos += fileAccessI.write(b,0,nRead); al+ #y)+  
//if(nThreadID == 1) i!~'M;S  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1.q_f<
U  
} s6o>m*{  
M/z}p  
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Utility.log("Thread " + nThreadID + " is over!"); 3gQPKBpc  
bDownOver = true; e5Mln!.o  
//nPos = fileAccessI.write (b,0,nRead); d`d0N5\  
} A?Wk wf  
catch(Exception e){e.printStackTrace ();} \(p{t  
} u>
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} |Oag,o"  
p h[\)  
h3gWOU  
//打印回应的头信息 IHC1G1KW=A  
public void logResponseHead(HttpURLConnection con)
:D7|%KK  
{ oRp:B&  
for(int i=1;;i++) TEsnNi 1  
{ D7"p}PD>~  
String header=con.getHeaderFieldKey(i); [i]r-|_K  
if(header!=null) \C5%\4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $OVXk'cc  
Utility.log(header+" : "+con.getHeaderField(header)); xLZd!>C  
else F\ctuaLC  
break; 8e0."o.6  
} s/Xb^XjS1  
} htP|3B  
1nPZ<^A&@  
w{ `|N$  
public void splitterStop() #0;HOeIiH  
{ j8 C8X$  
bStop = true; eo^/c+FG  
} $j)hNWI  
2AVc? 9@  
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} _y .]3JNm  
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_~aG|mAj
 
/* S'B6jJK2x  
**FileAccess.java x
v7"WFb  
*//文件访问(定位，写) ;3C:%!CdA]  
package NetFox; ;7Oi!BC  
import java.io.*; A>.2OC+  
ji
+{ :D  
}jSj+*  
public class FileAccessI implements Serializable{ N_75-S7Cm  
#
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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 ^%y
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RandomAccessFile oSavedFile; {F|48P;J  
long nPos; .I$}KE)  
^;F{)bmu+)  
;HOPABWz)  
public FileAccessI() throws IOException #ZiT-  
{ 8
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this("",0); Kud'pZ{P  
} z2/!m[U  
oN(-rWdhZ  
t^EhE  
public FileAccessI(String sName,long nPos) throws IOException #G3N(wV3  
{ 6Gn4aso
A  
oSavedFile = new RandomAccessFile(sName,"rw"); A[UP"P~u/  
this.nPos = nPos; #k5#j4!b  
oSavedFile.seek(nPos); N<z`yV  
} |sgXh9%x<  
5nCu~<uJ  
``?6=mO  
public synchronized int write(byte[] b,int nStart,int nLen) A~lIa$U$b  
{ >{Rb 3Z]  
int n = -1; &d`^E6#  
try{ m(sXk}e;1  
oSavedFile.write(b,nStart,nLen); xk~Nmb}  
n = nLen; <M[U#Q~?~e  
} $M"0BZQ?y!  
catch(IOException e) O2-M1sd$  
{ MmU%%2QG  
e.printStackTrace (); Uedvc5><t  
} <8(?7QI  
(&&87(  
:
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return n; [~Hg}-c  
} 0o&}mKe  
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} SlT*C6f  
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/*  YRB%:D@u  
**SiteInfoBean.java Fm j=  
*/ g{pQ4jKF  
package NetFox; |Svk^mq  
#A <1aQ  
&A50'8B2A  
public class SiteInfoBean { #GqTqHNE<  
XKLF8~y8A  
4?]oV%aP)  
private String sSiteURL; //Site's URL T<jfAE  
private String sFilePath; //Saved File's Path wFlV=!>,  
private String sFileName; //Saved File's Name DOL%'k?B  
private int nSplitter; //Count of Splited Downloading File Sw! j=`O  
xNdIDj@  
, &' Y  
public SiteInfoBean() O25mkX  
{//nSplitter的缺省值为5 %]Cjhs"v  
//default value of nSplitter is 5 @sf90&f  
this("","","",5); ]O!s'lC  
} IKf`[_,t]  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,@Z_{,b  
{ C*wdtEGq  
sSiteURL= sURL; kN'Thq/ZE  
sFilePath = sPath; Mz|L-62  
sFileName = sName; 6 nGY^  
this.nSplitter = nSpiltter; -gKpL\  
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3;BvnD7  
} VbxAd 2')  
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public String getSSiteURL() P%GkcV  
{ %RFYm  
return sSiteURL; ch,|1}bi  
} y1(P<7:t?  
ujx-jIhT_  
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public void setSSiteURL(String value) QN 0rE@a  
{ SgSk!lj  
sSiteURL = value; x1DVD!0~{  
} _.f@Y`4d  
-^fzsBL.  
1~qm+nET\  
public String getSFilePath() F_PTMl=Q|J  
{ p5SX1PPQ  
return sFilePath;  1KJZWZy  
} c/$*%J<  
+sn2Lw!^  
<:cpz* G4  
public void setSFilePath(String value) 0(TvQ{  
{ Zps&[;R$-  
sFilePath = value; ^('cbl  
} tP]q4i
 
^-L{/'[8M  
rsSue_Q  
public String getSFileName() RSH/l;ii  
{ ;F,qS0lzE  
return sFileName; jT"r$""1d  
} ?cBO6^  
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T 'i~_R6  
public void setSFileName(String value) 2 zl~>3S  
{ 1#!@["  
sFileName = value; oWrE2U;  
} 83?1<v0%  
X<K9L7/*  
^n71'MW  
public int getNSplitter() <UAP~RH{  
{ 5byeWH0n3  
return nSplitter; }@*I+\W/  
} foyB{6q8  
{*__B} ,N  
8|vld3;  
public void setNSplitter(int nCount) ruHrv"29  
{ .WO/=#O  
nSplitter = nCount; qhwoV4@f  
} kC|Tubs(  
} %LcH>sV  
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0:PSt_33F  
/* w7ZG oh(  
**Utility.java a],h<wGEx  
*/ d"!yD/RD  
package NetFox; l qXc  
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|Pf(J;'[  
public class Utility { D@5s8xv  
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public Utility() .S6ji~;r  
{
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-=>U =|  
() <`t}FQ  
} @4@PuWI0-  
<hMtE
/05B  
//线程睡眠 Z{#"-UG  
public static void sleep(int nSecond) NJ>,'s  
{ Za9$Hh/X  
try{ :r^klJ(m  
Thread.sleep(nSecond); [lOf|^9  
} |I/,F;'  
catch(Exception e)
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{ - &NQ\W  
e.printStackTrace (); 86#-q7aX  
} ${@q?iol  
} 4D GY6PS  
Y@ObwKcG  
//日志 Kc-4W6?$  
public static void log(String sMsg) v#Sj|47  
{ 'Y ,1OK  
System.err.println(sMsg); fIH#  
} 5<^'Cy
 
\P5>{2i  
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public static void log(int sMsg) }!=gP.Zu^  
{ {Wa~}1`Kl  
System.err.println(sMsg); p}&Md-$1  
} y]<#%Fh  
} Wge ho  
hRRkFz/0&  
O%prD}x  
/* NA=#>f+U%  
**TestMethod.java x!`b'U\  
*/ A1=_nt)5  
package NetFox; =hPG_4#  
5^b i 7J  
)7k&`?Mh  
public class TestMethod { U @)k3^
 
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keaj3#O  
public TestMethod() ia_Z\q  
{ ///xx/weblogic60b2_win.exe TbMdQbj}  
try{ !5? m  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Rnzqw,q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); B(8mH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); </|)"OD9  
fileFetch.start(); A3z/Bz4]:#  
} YWSz84d  
catch(Exception e){e.printStackTrace ();} u]P03B  
_yNT=#/  
LSSW.Oz2L  
} %V31B\]Nz7  
:Jjw"}SfK#  
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public static void main(String[] args) AvyQ4xim+  
{ 6$;L]<$W>  
new TestMethod(); (*MNox?w  
} B
>sCP"/uV  
} Sf=F cb  
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