http断点续传简单实现（java)

/* TsF>Y""*M  
**SiteFileFetch.java &xLCq&j
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*/ Op5S
'  
package NetFox; ?2nF1>1  
import java.io.*; x2h5,.K  
import java.net.*; l|j}Ggen  
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public class SiteFileFetch extends Thread { <! Z06  
%3Tz%>n  
;"w?@ELE  
SiteInfoBean siteInfoBean = null; //文件信息Bean O48*"Z1  
long[] nStartPos; //开始位置 %CIRN}  
long[] nEndPos; //结束位置 3%L@=q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ><wYk)0E  
long nFileLength; //文件长度 O6"S=o&  
boolean bFirst = true; //是否第一次取文件 kHbH{])  
boolean bStop = false; //停止标志 *
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File tmpFile; //文件下载的临时信息 Xy]Pmt  
DataOutputStream output; //输出到文件的输出流 yvIzgwN%s!  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） SX]uIkw  
public SiteFileFetch(SiteInfoBean bean) throws IOException !g7lJ\
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{ 1LVO0lT  
siteInfoBean = bean; zff<#yK1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H;c3 x"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vf;&0j&`  
if(tmpFile.exists ()) bae\EaS ?  
{ \e9rXh%  
bFirst = false; svvl`|n%  
read_nPos(); M2!2J  
} i`^[_  
else RdqB^
>
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{
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nStartPos = new long[bean.getNSplitter()]; YhQ%S}  
nEndPos = new long[bean.getNSplitter()]; N;S1s0FN  
} {1;R&  
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} "[dfb#0z`  
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public void run() b_Dd$NC  
{ B'&QLO|  
//获得文件长度 %R^*MUTx  
//分割文件 +3[8EM#g  
//实例FileSplitterFetch b?K`DUju{0  
//启动FileSplitterFetch线程 a.2Xl}2o5  
//等待子线程返回 =/Ph]f9  
try{ I
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if(bFirst) (v}4,'dS  
{ i]15g@  
nFileLength = getFileSize(); }D[j6+E  
if(nFileLength == -1) p(!d,YSE  
{ *f o>  
System.err.println("File Length is not known!"); ipC <p?PpR  
} vYg>^!Q  
else if(nFileLength == -2) n7/>+V+  
{ } 89-U  
System.err.println("File is not access!"); bm poptfL  
} X]}:WGFM  
else &embAqW:  
{ .'
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for(int i=0;i<nStartPos.length;i++) eX'U d%  
{ <,*3Av  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2(U;{;\n*  
} ^*"i *e  
for(int i=0;i<nEndPos.length-1;i++) >%H(0G#X  
{ 2b K1.BD  
nEndPos = nStartPos[i+1]; /B<QYvv  
} K%ptRj$  
nEndPos[nEndPos.length-1] = nFileLength; ~P BJ~j+G  
} dh_c`{9  
} ^[6el_mj  
..7"<"uH  
^
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//启动子线程 ly#jl5wmT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I-^C6~  
for(int i=0;i<nStartPos.length;i++) $!$,cKPl5  
{ &dG^M2g-F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
>hY.F/[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H128T8?r[  
nStartPos,nEndPos,i); b|-S;cw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m*.+9 6  
fileSplitterFetch.start(); _:]g:F[ #  
} tb4^+&.GS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :DrF)1C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); C55Av%-=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tl;b~k  
nEndPos = " + nFileLength); 20# V?hX3  
// fileSplitterFetch[nPos.length-1].start(); l5#SOo\  
=!\Y;rk  
d ehK#8  
//等待子线程结束 Xe&p.v  
//int count = 0; qKrxln/T  
//是否结束while循环 6qSsr]  
boolean breakWhile = false; 6AdC  
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while(!bStop) ^YJ%^P  
{ Z~].v._YV)  
write_nPos(); Zo,066'+[.  
Utility.sleep(500); L{rd',  
breakWhile = true; W{c Z7$d  
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for(int i=0;i<nStartPos.length;i++) =*R6O,  
{ O7p=N8V  
if(!fileSplitterFetch.bDownOver) a7685Y  
{ CeeAw_*@  
breakWhile = false; mV^~  
break; "n_X4e+18P  
} v-BQ>-&
s  
} c]n"1YNm  
if(breakWhile) fW[ .Q0  
break; 4xH/a1&p=  
FA+"t^q  
rsq?4+\  
//count++; ac\([F-  
//if(count>4) Gt+rVJ=v  
// siteStop(); o7s!ti\G  
} kD0bdE|  
o{hX?,4i  
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System.err.println("文件下载结束！"); SgYMPBh  
} }'*6 A  
catch(Exception e){e.printStackTrace ();} ujzfy  
} PQp =bX,  
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QYi4A"$`  
//获得文件长度 Tw7]   
public long getFileSize() lF_"{dS_6(  
{ -QwH|  
int nFileLength = -1; X`1R&K;z^  
try{ T2 S fBs  
URL url = new URL(siteInfoBean.getSSiteURL()); VFzIBgJ3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I]DD5l}\  
httpConnection.setRequestProperty("User-Agent","NetFox"); [(gXjt-  
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int responseCode=httpConnection.getResponseCode(); lB0`|UEb (  
if(responseCode>=400) y/5GY,z%aL  
{ Rw|'LaW  
processErrorCode(responseCode); 4v`IAR?&K;  
return -2; //-2 represent access is error .
!Pg)|  
} l&}}Io$?@  
NSBcYObX  
RWGf]V]6  
String sHeader; TDUY&1[  
PfZS"yk  
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for(int i=1;;i++) !LzA  
{ !sSq4K  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Mc<u?H  
//Utility.log(in.readLine()); @Ns[qn;9  
sHeader=httpConnection.getHeaderFieldKey(i); kY @(-  
if(sHeader!=null) L7d1)mV  
{ 0{g*\W*+~  
if(sHeader.equals("Content-Length")) X6",Xr!{  
{ 1`YU9?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (0B?OkQ  
break; DzQ  
} l#`G4Vf  
} &w#!
 
else c!_c, vwrn  
break;  ?C#E_  
} GB35ouE  
} #c
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catch(IOException e){e.printStackTrace ();} N+h05`  
catch(Exception e){e.printStackTrace ();} Pc_aEBq  
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Utility.log(nFileLength); _'LZf=V0  
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/("7*W2  
return nFileLength; BHf$ %?3z,  
} d&[RfZ`  
MUAs(M;  
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//保存下载信息（文件指针位置） IHYLM;@L  
private void write_nPos() dH!z<~  
{ Y}1c>5{bE  
try{ mL=d EQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); PO`p.("h  
output.writeInt(nStartPos.length); Aeb(b+=  
for(int i=0;i<nStartPos.length;i++) sVK?sBs]  
{ u0c}[BAF  
// output.writeLong(nPos); 8 {
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output.writeLong(fileSplitterFetch.nStartPos); 68Gywk3]=u  
output.writeLong(fileSplitterFetch.nEndPos); d<6F'F^w.7  
} 5$: toL  
output.close(); &cSVOsi  
} !:^q_q4  
catch(IOException e){e.printStackTrace ();} kIVQ2hmv  
catch(Exception e){e.printStackTrace ();} 4P&2Z0  
} "FWx;65CR  
Y @p<f5[c  
p
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//读取保存的下载信息（文件指针位置） l!F$V;R  
private void read_nPos() BVw2skOT  
{ RZzHl
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try{ ujZ`T0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bI55G#1G  
int nCount = input.readInt(); _cX}!d!j  
nStartPos = new long[nCount]; @"-\e|[N  
nEndPos = new long[nCount]; \</!kY*3@t  
for(int i=0;i<nStartPos.length;i++) V0=%$tH  
{ [b:&y(  
nStartPos = input.readLong(); gvA}s/
  
nEndPos = input.readLong(); -2M~KlYl  
} S^eem_
C  
input.close(); y|2<Vc  
} x,!Dd  
catch(IOException e){e.printStackTrace ();} 1)56ec<c  
catch(Exception e){e.printStackTrace ();} sD:o 2(G*  
} UX@%1W!8  
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private void processErrorCode(int nErrorCode) w
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{ ^$K&Met  
System.err.println("Error Code : " + nErrorCode); Yv5H41o"  
} u4C9ZYN  
*Jd"3Si/  
V4n~Z+k  
//停止文件下载 .eR1\IAm  
public void siteStop() H#~gx_^U  
{ P>VoA  
bStop = true; )*~A|[  
for(int i=0;i<nStartPos.length;i++) ;
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fileSplitterFetch.splitterStop(); 2'DCB{Jv  
)l7XZ_gw'  
;=Ma+d#  
} *an Ng<@  
} >fH0>W+!  
//负责部分文件的抓取 Vr1}Zv3K'  
**FileSplitterFetch.java 6ZqU:^3  
*/ bj pruJ`=  
package NetFox; cZYy+  
_MBhwNBxZ  
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import java.io.*; )G/bP!^+(  
import java.net.*; Q":_\inF  
m/KaWrw/)  
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public class FileSplitterFetch extends Thread { Ghgn<YG  
HwUaaK   
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String sURL; //File URL ppyy0E^M  
long nStartPos; //File Snippet Start Position ^M'(/O1  
long nEndPos; //File Snippet End Position {821e&r  
int nThreadID; //Thread's ID CS7b3p!I  
boolean bDownOver = false; //Downing is over u>*a@3$f  
boolean bStop = false; //Stop identical 'J,UKK\5  
FileAccessI fileAccessI = null; //File Access interface 5/=$p:
E>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /)ZjI W"|  
{ FDMQLxf  
this.sURL = sURL; jHFjd'  
this.nStartPos = nStart; Uwc%'=@  
this.nEndPos = nEnd; Lce,]z\_  
nThreadID = id; g\q .  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xMJ-=  
}  FA+HR  
j3Od7bBS]  
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public void run() hX.cdt_?  
{ uf6egm5]  
while(nStartPos < nEndPos && !bStop) _3`GZeGV  
{ Jt_=aMY:7  
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try{ ^?cu9S3  
URL url = new URL(sURL); yu;EL>G_AY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [V'c
 
httpConnection.setRequestProperty("User-Agent","NetFox"); )Te\
6qM  
String sProperty = "bytes="+nStartPos+"-"; Tn7Mt7h  
httpConnection.setRequestProperty("RANGE",sProperty); Y~UuT8-c  
Utility.log(sProperty); `% 9Y)a/e  
|! 9~  
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InputStream input = httpConnection.getInputStream(); +(+lbCW/  
//logResponseHead(httpConnection); xV> .]  
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/!]K+6>
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byte[] b = new byte[1024]; 7X$CJ%6b  
int nRead; iC#a+G*N_M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '.v;/[0  
{ -wn-PB@r  
nStartPos += fileAccessI.write(b,0,nRead); +~5Lo'^  
//if(nThreadID == 1) o?a2wY^
_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L4po1  
} /@`"&@W'  
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Utility.log("Thread " + nThreadID + " is over!"); Fp.eucRxP  
bDownOver = true; 7ys' [G|}r  
//nPos = fileAccessI.write (b,0,nRead); @K"$M>n$Z  
} OX;bA^+}P  
catch(Exception e){e.printStackTrace ();} If&))$7u  
} h% -=8l,  
} JI@iT6.%IX  
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//打印回应的头信息 ToHx!,tDS  
public void logResponseHead(HttpURLConnection con) MV5$e  
{ 5RT#H0/+  
for(int i=1;;i++) D1RQkAZS  
{ |j+JLB  
String header=con.getHeaderFieldKey(i); !zK"y[V  
if(header!=null) ui?@:=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y1Ql_  
Utility.log(header+" : "+con.getHeaderField(header)); {MtJP:8Jp  
else RPX.?;":  
break; \#[DZOI~  
} [vr"FLM|9  
}  ]!ZZRe  
!
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public void splitterStop() (6fD5XtS  
{ -c>3|bo  
bStop = true; ndQw>  
} PcsYy]Q/  
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} W%rUa&00  
O]IAIM  
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/* @.L#u#   
**FileAccess.java ^C K!=oO  
*//文件访问(定位，写) |21VOPBS  
package NetFox; ZKI8x1>Iq  
import java.io.*; Q%6zr9  
D&fOZVuqZ  
3uw3[ SR1  
public class FileAccessI implements Serializable{ HDhkg-QC  
PVi;h%>Y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %|4Kak]:Q  
RandomAccessFile oSavedFile; OTYkJEC8\N  
long nPos; H0b{`!'Fs:  
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public FileAccessI() throws IOException :"y2u   
{ h7eb/xEto  
this("",0); RSAGSGp  
} Wt%Wpb8
  
/\,3AInLb  
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public FileAccessI(String sName,long nPos) throws IOException uBG!R
#T  
{ mBL?2~M  
oSavedFile = new RandomAccessFile(sName,"rw"); SEnr"
}  
this.nPos = nPos; PC5$TJnj3  
oSavedFile.seek(nPos);
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} /{j._4c  
?* +>T@MH  
|

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public synchronized int write(byte[] b,int nStart,int nLen) wKJ|;o4;L  
{ _ow7E\70  
int n = -1; \Ec*Gq?.  
try{ n:a~=^IV  
oSavedFile.write(b,nStart,nLen); +6:
  
n = nLen; oHfr glGX  
} #)L}{mHLM-  
catch(IOException e) E\}A<r  
{ _*z^PkH  
e.printStackTrace (); D<70rBf2  
} n"?*"Ya  
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return n; T: My3&6  
} y ~-v0/  
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} IT#Li  
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/* k v_t6(qd  
**SiteInfoBean.java {^Q,G x(  
*/ ;mI^J=V3  
package NetFox; ,+d8   
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public class SiteInfoBean { AP`1hz4].-  
~[F7M{LS  
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private String sSiteURL; //Site's URL @[v,q_^8  
private String sFilePath; //Saved File's Path R:l&2  
private String sFileName; //Saved File's Name nWc@ufY  
private int nSplitter; //Count of Splited Downloading File eKuF7Oo  
Sz|kXk6&9  
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public SiteInfoBean() ZJ+ad,?,  
{//nSplitter的缺省值为5 J(8?6&=ck  
//default value of nSplitter is 5 2xUgM}e
 
this("","","",5); "3
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} GwA\>qXw  
\HrtPm`e  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r#oJch=  
{ iDcYyNE  
sSiteURL= sURL; "J*>g(H53  
sFilePath = sPath; Af@\g-<W_  
sFileName = sName; |aU8WRq  
this.nSplitter = nSpiltter; 9,&xG\z=  
gB%"J
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]Ar,HaX-  
} RnC+]J+?4  
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public String getSSiteURL() ukVBC"Ny  
{ sZ7,7E|_  
return sSiteURL; XgXXBKf$  
} Z0v?3v}9^  
}
(DH_0  
1=T;68B  
public void setSSiteURL(String value) @*|UyK.   
{ ]a.^F
 
sSiteURL = value; :+w6i_\d5  
} 2~QJ]qo=  
db_}][;.c  
Y~!A"$  
public String getSFilePath() ZI4dD.B  
{ F/1m&1t  
return sFilePath; B#`'h~(7  
} 1R yE8DdP  
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h 2JmRO  
public void setSFilePath(String value) =z"8#_3A  
{ t_16icF9U  
sFilePath = value; PJ&L7  
} )FG/   
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public String getSFileName() +e.w]\}  
{ T~L V\}h  
return sFileName; q$b4S4Z7  
} FG!hb?_1  
br TP}A  
#*w)rGkU2  
public void setSFileName(String value)
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{ {98e_z w  
sFileName = value; 8lDb<i  
} V?0IMc  
L^Q;M,.c;  
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public int getNSplitter() L<iRqayn  
{ {_Ll'S  
return nSplitter; ")
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} 9LBZMQ  
Dm}M8`|X  
zkqn>  
public void setNSplitter(int nCount) 4W49*Je  
{ z%T|L[(6  
nSplitter = nCount; L AA(2  
} XpkOCo02  
} |'P$zMAF  
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 .9r85  
/* %{3q=9ii  
**Utility.java 7{w}0PMx  
*/ %\|{_]h}y  
package NetFox; QY<5o;m`  
'+vmC*-I(  
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public class Utility { `jr?I {m;  
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kw#-\RR_c  
public Utility() %QGw`E   
{ Fsx<Sa  
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} -r3 s{HO  
u3,O)[qV  
//线程睡眠 P7Qel,  
public static void sleep(int nSecond) gJ9"$fIPc  
{ e3p:lu  
try{ zA.0Sm  
Thread.sleep(nSecond); 53a
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} j!%^6Io4  
catch(Exception e) ^Mc9MZ)  
{ |</)6r  
e.printStackTrace (); (C).Vj~  
} Ar,n=obG  
} ,p(&G_  
Ks6\lpr  
//日志 /Yg&:@L  
public static void log(String sMsg) S
++~w9}  
{ Yc_(g0NK  
System.err.println(sMsg); H=f|X<8  
} ]b sabS?  
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to,\n"$~!  
public static void log(int sMsg) F
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{ )$df6sq  
System.err.println(sMsg); 3/ }  
} Qr7v^H~E4.  
} 0x]?rd+q8Q  
hh%?E\qM  
f^u-Myk  
/* $7g+/3Fu^  
**TestMethod.java f38e(Q];m  
*/ 6'@{ * u  
package NetFox; x{<l8vL=-c  
Vr( Z;YO  
y35~bz^2  
public class TestMethod { a@qc?  
>{:hadUH  
dY~z6bT  
public TestMethod() p)?6#~9$  
{ ///xx/weblogic60b2_win.exe EEL3~H{
(  
try{ S7PWP<9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); hKWWN`;b !  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =EA:fq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oo7}Hg>  
fileFetch.start(); xY!ud)  
} Nf3UVK8LtS  
catch(Exception e){e.printStackTrace ();} 3z2 OW@zL$  
6(4d3}F  
6Xm'^T  
} T:m" eD;  
CPRVSN0b{4  
{$yju_[  
public static void main(String[] args) /"j3B\`?  
{ ;`:YZ+2 Z  
new TestMethod(); 1
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} ,#&7+e!]>P  
} 5Lej_uqF   
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