http断点续传简单实现（java)

/* 5s`r&2 w  
**SiteFileFetch.java 8UqH"^9.Q7  
*/ n\JI7A}  
package NetFox; 2l^_OrE!  
import java.io.*; 7C,giCYU  
import java.net.*; y)CvlI  
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public class SiteFileFetch extends Thread { jY]51B
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean *L$_80  
long[] nStartPos; //开始位置 " r o'?  
long[] nEndPos; //结束位置 yRXWd*9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ms&1P  
long nFileLength; //文件长度 v~x4Y,m%  
boolean bFirst = true; //是否第一次取文件 OH
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boolean bStop = false; //停止标志 ci$J?a  
File tmpFile; //文件下载的临时信息 Ef28  
DataOutputStream output; //输出到文件的输出流 *KY:U&*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） m|c[C\)By  
public SiteFileFetch(SiteInfoBean bean) throws IOException vgD
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{ GQ7uxdqWBQ  
siteInfoBean = bean; NlKVl~_ C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )OxcCV?5Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); rVl 8?uy  
if(tmpFile.exists ()) fi`\e W  
{ (tg9"C  
bFirst = false; [YHtBM:y  
read_nPos(); (=Kv1 HaD  
} o.0tD  
else \U>&W  
{ VwPoQ9pIS  
nStartPos = new long[bean.getNSplitter()]; "NGfT:HV  
nEndPos = new long[bean.getNSplitter()]; [xr^t1  
} )E>yoUhN  

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} yV\%K6d|3&  
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public void run() PS+~JwDUc  
{ NLG\*mQ  
//获得文件长度 4\ Xaou2V[  
//分割文件 -$[&{.B.  
//实例FileSplitterFetch 1Z @sh>X|  
//启动FileSplitterFetch线程 =f{v:n6  
//等待子线程返回 rz k;Q@1  
try{ >$L7J=Em  
if(bFirst)
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{ C)EP;5k'!\  
nFileLength = getFileSize(); A`Y^qXFb`  
if(nFileLength == -1) It&CM,=t  
{ z06,$OYz  
System.err.println("File Length is not known!"); /YHO"4Z  
} d-+jb<C&  
else if(nFileLength == -2) w3);ZQ|  
{ U{M3QOF  
System.err.println("File is not access!"); d9;&Y?fp  
} &|#[.ti1  
else 2(@2z[eKr  
{ xwof[BnEZ  
for(int i=0;i<nStartPos.length;i++) |`#fX(=  
{ 0 h!Du|?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L#byYB;E{  
} T[k$[  
for(int i=0;i<nEndPos.length-1;i++) |yeQz  
{ 0
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nEndPos = nStartPos[i+1]; <;PKec  
} J*$%d1  
nEndPos[nEndPos.length-1] = nFileLength; $$1t4=Pz  
} Zdqm|_R[  
} |;wc8;  
gI;"PkN  
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//启动子线程 \\KjiT'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^?+[yvq  
for(int i=0;i<nStartPos.length;i++) P{6$".kIY  
{ Rq5'=L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '!7>*<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), '%[ Y  
nStartPos,nEndPos,i); goIvm:
?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~. vridH  
fileSplitterFetch.start(); {&IB[Y6  
} ;98b SR/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7UMZs7L$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0HoHu*+FX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aM;SE9/U  
nEndPos = " + nFileLength); :)lG}c  
// fileSplitterFetch[nPos.length-1].start(); |di(hY|  
S=!WFKcJR  
?`Yu~a{  
//等待子线程结束 .k]`z>
uv  
//int count = 0; (is',4^b  
//是否结束while循环 $ItmYj.m  
boolean breakWhile = false; s"`~Xnf  
m.m6.  
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while(!bStop) j}ob7O&U'w  
{ =?6c&Z  
write_nPos(); [8sYEh  
Utility.sleep(500); ,X^3.ILz  
breakWhile = true; 8O'bCBhv  
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r
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for(int i=0;i<nStartPos.length;i++) :kR>wX  
{ c#{lXS^  
if(!fileSplitterFetch.bDownOver) =6Ok4Z  
{ iF^qbh%%E  
breakWhile = false; ^:{8z;w!(  
break; xX%ppD7  
} \(i'iC  
} l[$GOLeS  
if(breakWhile) cj>UxU][eS  
break; 7s?#y=M  
7! >0  
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//count++; . fja;aG  
//if(count>4) e+lun -  
// siteStop(); agx8*x  
} `CS\"|z  
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System.err.println("文件下载结束！");
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} H_RfIX)X  
catch(Exception e){e.printStackTrace ();} iN Oj@3x  
} %(W&
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//获得文件长度 0* F` h  
public long getFileSize() f X[xZGV,  
{ E,R
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int nFileLength = -1; UF!qp  
try{ d*d:-f~q  
URL url = new URL(siteInfoBean.getSSiteURL()); 3O2G+G2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rH`\UZ{cc  
httpConnection.setRequestProperty("User-Agent","NetFox"); prj(  
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int responseCode=httpConnection.getResponseCode(); i;1pw_K  
if(responseCode>=400) @FN|=
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{ nKm# kb  
processErrorCode(responseCode); p [C 9g  
return -2; //-2 represent access is error 0 MK}  
} 5VTVx1P[8  
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String sHeader; -n9&W  
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for(int i=1;;i++) T&'Jc  
{ ?A|JKOst]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wPM>-F  
//Utility.log(in.readLine());  bH
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sHeader=httpConnection.getHeaderFieldKey(i); v-z%3x.f  
if(sHeader!=null) Ih:Q}V#6  
{ dzOco)y  
if(sHeader.equals("Content-Length")) kku<0<(N  
{ JI.=y5I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _s5^\~ao  
break; H}kZ;8  
} [ *Dj:A)V^  
} C~pas~  
else %cSx`^`6j  
break; ~Q_7HJ=^$  
} X3}eq|r9  
} cOV9g)7^O  
catch(IOException e){e.printStackTrace ();} M)oKtiav*  
catch(Exception e){e.printStackTrace ();} 5FR#CQ  
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Utility.log(nFileLength); 3Q
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return nFileLength; xZ`z+
)  
} (-WRZLOQ  
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|)!f".`  
//保存下载信息（文件指针位置） .3C::~:  
private void write_nPos() qqw P4ceG  
{ ,kJ7c;:i  
try{ >O\+9T@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); CKn2ZL  
output.writeInt(nStartPos.length); _dm0*T ?  
for(int i=0;i<nStartPos.length;i++) &qS%~h%2  
{ u$R5Q{H_  
// output.writeLong(nPos); ! eZls  
output.writeLong(fileSplitterFetch.nStartPos); wU+r]SK@  
output.writeLong(fileSplitterFetch.nEndPos); 7G_<+rn  
} \~*<[.8~  
output.close(); D:Q#%wJ  
} o^~ZXF}  
catch(IOException e){e.printStackTrace ();} g}0K@z3  
catch(Exception e){e.printStackTrace ();} T$lV+[7  
} .+1I>L  
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//读取保存的下载信息（文件指针位置） 62HA[cr&)  
private void read_nPos() 06]3+s{{  
{ a5#G48'X  
try{ hP+4{F*}-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |s! _;6  
int nCount = input.readInt(); jM$bWtq2  
nStartPos = new long[nCount]; qt@/  
nEndPos = new long[nCount]; +4%~.,<_to  
for(int i=0;i<nStartPos.length;i++) L-w3A:jk  
{ lV^#[%  
nStartPos = input.readLong(); ndLEIqOY  
nEndPos = input.readLong();  ,RR{Y-  
} p*c(dkOe8  
input.close(); by>%}#M  
} Z2M(euzfi3  
catch(IOException e){e.printStackTrace ();} Y|LL]@Lv  
catch(Exception e){e.printStackTrace ();} k";dK*hD,  
} C!^A\T7p  
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private void processErrorCode(int nErrorCode) ooJxE\L
  
{ `'s_5Ek  
System.err.println("Error Code : " + nErrorCode); DYf2V6'  
} >;4q  
 ~frsgHW  
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//停止文件下载 }9\_s*  
public void siteStop() mvjx &+q  
{ nKGQU,C  
bStop = true;  9Do75S{(  
for(int i=0;i<nStartPos.length;i++) $^fF}y6N  
fileSplitterFetch.splitterStop(); 1TQ?Fxj  
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} 73X*|g  
} J-<P~9m~I  
//负责部分文件的抓取 XDCm
 
**FileSplitterFetch.java 7N 0Bj!  
*/ xK6`|/e  
package NetFox; clU ?bF~e1  
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import java.io.*; y7UU'k`  
import java.net.*; tlQ6>v'  
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public class FileSplitterFetch extends Thread { iO*5ClB  
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String sURL; //File URL d=bKNA90  
long nStartPos; //File Snippet Start Position Oz%6y ri  
long nEndPos; //File Snippet End Position #|E#Rkw!  
int nThreadID; //Thread's ID 6ZI
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boolean bDownOver = false; //Downing is over 01@WU1IN  
boolean bStop = false; //Stop identical S Q:H2vvD  
FileAccessI fileAccessI = null; //File Access interface :0y-n.-{  
>!1]G"U  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MPUyu(-%{  
{ enPtW  
this.sURL = sURL; y<6Sl6l*  
this.nStartPos = nStart; ^4`x:6m  
this.nEndPos = nEnd; p'LLzc##  
nThreadID = id; E}4{{{r  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9mHCms  
} /UunWZ u%  
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public void run() a&G{3#l  
{ N>3{!K>/Y:  
while(nStartPos < nEndPos && !bStop) R7rM$|n=o  
{ d"n>Q Tn\  
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try{ BaIpX<$T  
URL url = new URL(sURL); nq?+b >//
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 75H!i$(*+  
httpConnection.setRequestProperty("User-Agent","NetFox"); SHYekX  
String sProperty = "bytes="+nStartPos+"-"; g"n>v c7  
httpConnection.setRequestProperty("RANGE",sProperty); TFb7P/g  
Utility.log(sProperty); ]7<$1ta  
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InputStream input = httpConnection.getInputStream(); e*'bY;8lo  
//logResponseHead(httpConnection); }BS EK<W  
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byte[] b = new byte[1024]; hvTc( 0;mB  
int nRead; ,9G'1%z,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^e^-1s S  
{ agfDx^,  
nStartPos += fileAccessI.write(b,0,nRead); L$c 1<7LU  
//if(nThreadID == 1) 5(#z)T  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7Q{&L#;  
} 4wKCzPy  
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Utility.log("Thread " + nThreadID + " is over!"); kVsX/~$  
bDownOver = true; LiHJm-  
//nPos = fileAccessI.write (b,0,nRead); Mm8_EjMp  
} qDGx(d  
catch(Exception e){e.printStackTrace ();} NblPVxS  
} 8Q/cJ+&  
} 4?@5JpC9VA  
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//打印回应的头信息 "n3n-Y#'  
public void logResponseHead(HttpURLConnection con) #vK99S2  
{ EIzTbW{p  
for(int i=1;;i++) e?(4lD)d  
{ ^Vth;!o  
String header=con.getHeaderFieldKey(i); Z .`+IN(>E  
if(header!=null) t_I-6`8o]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); nZj&Ma7R  
Utility.log(header+" : "+con.getHeaderField(header)); pDP* 3  
else 6$PQ$  
break; =^M Q 4  
} %
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} vB7]L9=@"  
}c8et'HYf  
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public void splitterStop() lz0dt<8eP  
{ 8B6(SQp%  
bStop = true; U{EcV%C2  
} -"Kjn`8  
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} /!&eP3
^  
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/* M&Q&be84  
**FileAccess.java tWZ8(E$  
*//文件访问(定位，写) 0Q>  
package NetFox; FFwu$S6e  
import java.io.*; HRahBTd(z  

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r8y,$Mv<)0  
public class FileAccessI implements Serializable{ 'h&>K,U?5  
f 4K)Z e  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +tkm,>s  
RandomAccessFile oSavedFile; #?M[
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long nPos; p/ZgzHyF  
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public FileAccessI() throws IOException Rz>@G>b:  
{ p*$=EomY  
this("",0); Rwj 3o  
} 1N]-WCxQ  
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public FileAccessI(String sName,long nPos) throws IOException `aMnTF5:  
{ 9@h-q(-  
oSavedFile = new RandomAccessFile(sName,"rw"); V?MaI.g
j  
this.nPos = nPos; +A 6kw%"  
oSavedFile.seek(nPos); "5,Cy3  
} , Z1 &MuV  
rI
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public synchronized int write(byte[] b,int nStart,int nLen) z5^Se!`5  
{ suX^"Io%!  
int n = -1; [mUC7Kpi  
try{ q 3,p=ijJ  
oSavedFile.write(b,nStart,nLen); l Hu8ADva  
n = nLen; +^,&z}( Ak  
} }i;!p Ue$  
catch(IOException e) i[vN3`*B  
{ 'Um\m  
e.printStackTrace (); s
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} r_^
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return n; k~Y_%#_  
} mk-L3H1@J3  
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} >
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{y!77>Q/  
/* rj eKG-Z@  
**SiteInfoBean.java :n}t7+(>U  
*/ DQ6pe)E|  
package NetFox; ltl(SIi  
+P*,i$MV  
y9GaxW*&  
public class SiteInfoBean { L#T`h}1Z  
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[+dTd2uZ<\  
private String sSiteURL; //Site's URL ~:4Mf/Ca  
private String sFilePath; //Saved File's Path ]\=M$:,RZ  
private String sFileName; //Saved File's Name 8{.:$T  
private int nSplitter; //Count of Splited Downloading File lgCOp%>  
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public SiteInfoBean() rI]n4>k{  
{//nSplitter的缺省值为5 D7N` %A8   
//default value of nSplitter is 5 {<^PYN>`  
this("","","",5); '6>nXp?)r  
} 4d]T`  
74Il]i1=  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }~Y#N  
{  0c:jwtf  
sSiteURL= sURL; 7[7Sm^Tw  
sFilePath = sPath; 9fb"R"(M  
sFileName = sName; ~F]If\b  
this.nSplitter = nSpiltter; 0>?78QL9<  
ld23^r  
;Q8rAsf9  
} +(2mHS0_
a  
1j^FNg~  
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public String getSSiteURL() SJI+$L\'  
{ D)LqkfJ}z^  
return sSiteURL; kKSn^qL*  
} $Xo_C_:B  
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public void setSSiteURL(String value) Y'i_EX|  
{ @7B!(Q  
sSiteURL = value; r \]iw v  
} wkZ}o,{*:  
8:0.Pi(ln@  
9Lxa?Y1  
public String getSFilePath() 9k!#5_ M  
{ KbF,jm5  
return sFilePath; d\aU rsPn  
} !xh.S#B  
ur`:wR] 2?  
2f@gR9T  
public void setSFilePath(String value) JS1''^G&.  
{ [VwoZX:  
sFilePath = value; (%EhkTb  
} fqU*y 6]  
i(XqoR-x  
7L&=z$U@m  
public String getSFileName() }Pe0zx.Ge  
{ {oN7I'>  
return sFileName; i50^%,  
} :<Y, f(c  
+3D3[.n  
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public void setSFileName(String value) _[.3I1kG  
{ [Y]\sF;J  
sFileName = value; y"SVZ} ;|  
} h"G#} C]  
u($y<Q)=  
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public int getNSplitter() hK&/A+*  
{ <$'OSN`!  
return nSplitter; GoNX\^A  
} ,0=:06l  
"+V.Yue`R  
f=Rx8I  
public void setNSplitter(int nCount) Mrlv(1PQT  
{ J0M7f]  
nSplitter = nCount; *:3`$`\54  
} ( XoL,lJ  
}  Ju#t^P  
H:BWv08~5  
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/* u%vq<|~-  
**Utility.java LCRZ<?O[|  
*/ {?' DZR s  
package NetFox; 2!b+}+:  
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public class Utility { bm_'giQ:  
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public Utility() C&m[/PJ~l  
{ EI*B(  
-*u7MFq_  
/=}w%-;/;  
} L}1|R*b  
>>voLDDd  
//线程睡眠 /8i3I5*  
public static void sleep(int nSecond) 7 Ld5  
{ X rVF %  
try{ j ,'$i[F'  
Thread.sleep(nSecond); 6WQT,@?  
} c3&;Y0SD  
catch(Exception e) h7|#7 d  
{ r9Wk7?w)  
e.printStackTrace (); O$ 7R<V  
} [;/ydE=  
} ShdE!q7  
;{79d8/=  
//日志 tB_GEt2M  
public static void log(String sMsg) f\}fUg2  
{ $]eITyC`P  
System.err.println(sMsg); Gvk)H$ni  
} QQUYWC
  
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^-9g_5  
public static void log(int sMsg) lU0'5!3R,  
{ +wU9d8W  
System.err.println(sMsg); RHdcRojF  
} )B86  
} -lL(:drn  
0Z{f!MOh  
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/* .mzy?!w0q  
**TestMethod.java P5Y:c@
u2  
*/ gwj+~vSfi  
package NetFox; >TT4;ph  
P".CZyI-i  
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public class TestMethod { |UN0jR  
XrY\ot`,D  
9K`(Ys&  
public TestMethod() 60B6~@]P  
{ ///xx/weblogic60b2_win.exe IvFxI#.ju  
try{ l&@]   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Fy^=LrH=D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); LE!xj 0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Tji G!W8  
fileFetch.start(); qU(,q/l  
} 3xSt -MA  
catch(Exception e){e.printStackTrace ();} -\OvOkr  
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kQ5mIJ9(  
} LD]a!e
Y  
slC 38  
tONX<rA|]  
public static void main(String[] args) p.1@4kgK&r  
{ a\60QlAk~  
new TestMethod(); \&K{v#g~  
} B|9)4f&\=R  
} KTr7z^  
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