http断点续传简单实现（java)

/* NA{?D
SP  
**SiteFileFetch.java 4<<T#oW.:G  
*/ >`)IdX  
package NetFox; #Nv)SCc  
import java.io.*; \ ~uY);  
import java.net.*; !McRtxq?~  
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public class SiteFileFetch extends Thread { b75en{aDi*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean i"OY=iw-N  
long[] nStartPos; //开始位置 (>M@Ukam:  
long[] nEndPos; //结束位置 MzpDvnI9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2&KM&NX~  
long nFileLength; //文件长度 oeF0t'%  
boolean bFirst = true; //是否第一次取文件 9`|~-b  
boolean bStop = false; //停止标志 jImw_Q  
File tmpFile; //文件下载的临时信息 GSaU:A
 
DataOutputStream output; //输出到文件的输出流 CMviR<.  
?D9>N'yH8  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;pVnBi  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y:KIaYkk  
{ tXW7G@  
siteInfoBean = bean; `#y?:s]e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z8*{i]j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); y#?AW`|  
if(tmpFile.exists ()) rpMjDjW  
{ Og/@w&  
bFirst = false; *^s^{0Ad  
read_nPos(); WEsX+okj  
} bTJ l  
else ^M7pCetjdW  
{ AB[#
  
nStartPos = new long[bean.getNSplitter()]; -;W`0k^  
nEndPos = new long[bean.getNSplitter()]; bPHtP\)  
} Vohd d_x  
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} |N%#;7  
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public void run() W*.
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{ &eY&6I  
//获得文件长度 Uk<2X
Gj  
//分割文件 zOsk'ZE&  
//实例FileSplitterFetch XTS%:S  
//启动FileSplitterFetch线程 /;9iDjG  
//等待子线程返回 ||o :A  
try{ /6Olq6V  
if(bFirst) @; 0t+  
{ Ers8J V  
nFileLength = getFileSize(); E.%_i8s  
if(nFileLength == -1) xQ~N1Y2W  
{ O]%Vh l  
System.err.println("File Length is not known!"); 3R)_'!R[B  
} j@C*kj;-  
else if(nFileLength == -2) g#s hd~e  
{ CCp&+LRvR  
System.err.println("File is not access!"); ;wKsi_``@  
} Z;[f,Oj  
else F,/yK-9  
{ KreF\M%Ke  
for(int i=0;i<nStartPos.length;i++) =+"=|cQ  
{ rJUXIV>z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 84jA)  
} (hn;C>B  
for(int i=0;i<nEndPos.length-1;i++) iiD}2yb  
{ a1 .+L  
nEndPos = nStartPos[i+1]; iJVm=0WS^  
} 1/<Z6 ?U  
nEndPos[nEndPos.length-1] = nFileLength; p$_X\,F  
} @8"c
T-  
} JLu>w:\  
%h"%G=:  
'Z82+uU%  
//启动子线程 XO,gEn&6V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3w$Ib}7  
for(int i=0;i<nStartPos.length;i++) HsRQiai*  
{ B~7]x;8h  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,Uu#41ZOKL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !7y:|k,ac  
nStartPos,nEndPos,i); 'm|PSwB7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VK3e(7b  
fileSplitterFetch.start(); k.Q4oyei  
} q:-1ul  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZP;WXB`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZDTp/5=?K/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H&h"!+t(#  
nEndPos = " + nFileLength); l$DQkbOj  
// fileSplitterFetch[nPos.length-1].start(); U~s-'-C/  
/Q\|u:oO,  
UMj8<Lq)j  
//等待子线程结束 4$MV]ldUI  
//int count = 0; 0p[-M`D  
//是否结束while循环 ;`:A(yN]T  
boolean breakWhile = false; -cs$E2 -  

}e0>Uk`[  
5%;=(Oig  
while(!bStop) $Eh:m&hq  
{ *D:uFo,xn  
write_nPos(); Zil<*(kv{  
Utility.sleep(500); zIy&gOX  
breakWhile = true; Xn*>qm  
DE!P[$J  
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for(int i=0;i<nStartPos.length;i++) I6RF;m:Jw  
{ r l>e~i  
if(!fileSplitterFetch.bDownOver) B'!I{LC  
{ s]Qo'q
2  
breakWhile = false; Fd1jElt  
break; }x(Ewr  
} >o|.0aw<  
} B> V)6\  
if(breakWhile) FN"Ye*d  
break; meArS*d  
`i{p6-U3  
#55_hY#  
//count++; 5 ]l8l+  
//if(count>4) hd~0qK  
// siteStop(); 9Je+|+s]  
} W'L  
WIYWql>*  
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System.err.println("文件下载结束！"); 5"2pU{xmK  
} a}5/?/  
catch(Exception e){e.printStackTrace ();} l }WvO]  
} w'zSV1  
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//获得文件长度 U_<k*o@
:  
public long getFileSize() X^7n/|%*.  
{ \<Di|X1  
int nFileLength = -1; pv@w 8*  
try{ C1po]Ott*  
URL url = new URL(siteInfoBean.getSSiteURL()); "T1A$DKw+R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =} flmUv~  
httpConnection.setRequestProperty("User-Agent","NetFox"); <P0&!yN  
'QQa :3<x  
@:K={AIa  
int responseCode=httpConnection.getResponseCode(); }
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if(responseCode>=400) OSIf>1  
{ xyyEaB  
processErrorCode(responseCode); n7(/ml+Q_  
return -2; //-2 represent access is error M{Hy=:K+  
} Z:.*fs5  
cn2SMa[@S  
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String sHeader; ]7J*(,sp  
7[It  
((T6z$:hA  
for(int i=1;;i++) *Z2#U?_  
{ 21 N!?DR  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  7;$[s6$  
//Utility.log(in.readLine()); k293
wS  
sHeader=httpConnection.getHeaderFieldKey(i); UYvdzCUh  
if(sHeader!=null) &Rt^G  
{ p61F@=EL  
if(sHeader.equals("Content-Length")) b0uWUI(=  
{ O>[B"mMt  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2}U:6w  
break; I;+>@Cn(g<  
} k@^T<Ci  
} 
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else )}
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break; n |Q'>  
} :[?65q{  
} {"mb)zr  
catch(IOException e){e.printStackTrace ();} npMPjknl  
catch(Exception e){e.printStackTrace ();} Uu~~-5  
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Utility.log(nFileLength);
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return nFileLength; 5q _n6
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} M+-1/vR *@  
1-}M5]Y  
M sQ=1  
//保存下载信息（文件指针位置） {9XQ~t"m^  
private void write_nPos() v%;Nyab6$  
{ ,$bK)|pGV  
try{ W
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output = new DataOutputStream(new FileOutputStream(tmpFile)); X.[8L^ldh  
output.writeInt(nStartPos.length); 8XD_p);Oy  
for(int i=0;i<nStartPos.length;i++) ]. 0;;v6)  
{ F5%I
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// output.writeLong(nPos); E{]PfUfFY  
output.writeLong(fileSplitterFetch.nStartPos); CtE <9?  
output.writeLong(fileSplitterFetch.nEndPos); dyVfDF  
} csj4?]gI  
output.close(); 495A\8#  
} S3gd'Bahq  
catch(IOException e){e.printStackTrace ();} cXbQ  
catch(Exception e){e.printStackTrace ();}
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} S^_F0</U,  
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//读取保存的下载信息（文件指针位置） Ti$_V_  
private void read_nPos() z?  Ck9  
{ qL~|bfN  
try{ /A93mY[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y@limkN:  
int nCount = input.readInt(); $PFE>=nM  
nStartPos = new long[nCount];  >f*Zf(F  
nEndPos = new long[nCount]; :I8HRkp  
for(int i=0;i<nStartPos.length;i++) A>%mJ3M  
{ +Sak_*fq  
nStartPos = input.readLong(); @P/6NMjZ^  
nEndPos = input.readLong(); zR5KC!xc  
} `Hd~H  
input.close(); l09DH+  
} =DwY-Ex  
catch(IOException e){e.printStackTrace ();} fr
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catch(Exception e){e.printStackTrace ();}  _:HQ4s@  
} |Q$9I#rv  
o ^""=Z  
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private void processErrorCode(int nErrorCode) Y7<
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{ b)7v-1N  
System.err.println("Error Code : " + nErrorCode); yny1i9 y  
} j> dL:V&`  
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//停止文件下载 9](RZ6A+o  
public void siteStop() m-lTXA(  
{ i=jYl  
bStop = true; PLRMW2  
for(int i=0;i<nStartPos.length;i++) 'mk_s4J  
fileSplitterFetch.splitterStop(); bVOJp% *s  
bp>M&1^KY  
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} 1!Afq}|  
} 3|=L1Pw#  
//负责部分文件的抓取 /&W~:F  
**FileSplitterFetch.java
,M=s3D8C  
*/ T+41,  
package NetFox; @k)[p+)E  
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import java.io.*; :H>0/^Mg0  
import java.net.*; <KFl4A~  
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public class FileSplitterFetch extends Thread { O3tw@ &k
 
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String sURL; //File URL wicW9^ik  
long nStartPos; //File Snippet Start Position iJS7g  
long nEndPos; //File Snippet End Position :ka^ztXG  
int nThreadID; //Thread's ID J$i.^|hE/  
boolean bDownOver = false; //Downing is over Nf%/)Tk  
boolean bStop = false; //Stop identical AA0\C_W0p  
FileAccessI fileAccessI = null; //File Access interface rDv`E^\  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j[Gg[7q{y  
{ OJD!Ar8Q  
this.sURL = sURL; (e4#9  
this.nStartPos = nStart; ~L:H]_8F l  
this.nEndPos = nEnd; 009Q#[A  
nThreadID = id; 7sU,<Z/D  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;*cCaB0u  
} !vq|*8  
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public void run() 2Y
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{ w9675D+  
while(nStartPos < nEndPos && !bStop)  rp=Y }  
{ avW33owb@  
{
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try{ c^stfFE&  
URL url = new URL(sURL); zBc |
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TT={>R[B  
httpConnection.setRequestProperty("User-Agent","NetFox"); *z&hXYm  
String sProperty = "bytes="+nStartPos+"-"; u>/Jb+  
httpConnection.setRequestProperty("RANGE",sProperty); i5SDy(?r  
Utility.log(sProperty); ANTWWs}  
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InputStream input = httpConnection.getInputStream(); ,n$NF0^l  
//logResponseHead(httpConnection); *d9RD~
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5,?^SK|'x  
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byte[] b = new byte[1024]; _gw paAJ  
int nRead; Xr
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f$qkb$?]}  
{ a}X.e
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nStartPos += fileAccessI.write(b,0,nRead); (*9-
Fa  
//if(nThreadID == 1) *W2o$_Hs  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *!ecb1U5  
} |)S*RQb\  
yB|1?L#  
#3?}MC  
Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; #I\" 'n5M  
//nPos = fileAccessI.write (b,0,nRead); E] rBq_S  
} :QC |N@C  
catch(Exception e){e.printStackTrace ();} nO#x"  
} ?C']R(fQ\  
} )r?-_qj=  
F
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//打印回应的头信息 e m  
public void logResponseHead(HttpURLConnection con) @hy~H?XN  
{ tVh"C%Vkr  
for(int i=1;;i++) Yr[&*>S  
{  HlEHk'  
String header=con.getHeaderFieldKey(i); [Y.=bfV!  
if(header!=null) Dt(xj}[tC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3i~X`@$k>  
Utility.log(header+" : "+con.getHeaderField(header)); k 7:Z\RGy  
else ,&L}^Up  
break; qfjUJ/  
} k U0.:Gcc  
} 6[?5hmc"w  
/ }*}r  
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public void splitterStop() x"r,l/gzy  
{ 1iqgVby  
bStop = true; Jhfw$DF  
} mF4y0r0  
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} mtdy@=?1Y  
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/* ~/XDA:nfL:  
**FileAccess.java M6GiohI_"P  
*//文件访问(定位，写) }Rw6+;  
package NetFox; J 5xMA-  
import java.io.*; }F"98s W  
t7Mq>rFB  
nLx|$=W  
public class FileAccessI implements Serializable{ sPXjU5uq#  
Pm,.[5uc  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )sNPWn8<Uy  
RandomAccessFile oSavedFile; lQEsa45  
long nPos; =T\=,B  
7D1$cmtH  
3_`)QYU'  
public FileAccessI() throws IOException JW)f'r_f  
{ T#wG]DH;  
this("",0); $x,EPRNs  
} mxpj<^n}  
K$w;|UJc  
|* ^LsuFb  
public FileAccessI(String sName,long nPos) throws IOException H \'1.8g/  
{ vn!3Z!dm(  
oSavedFile = new RandomAccessFile(sName,"rw"); p_X{'=SQ1  
this.nPos = nPos; k1ja ([Q  
oSavedFile.seek(nPos); kW1w;}n$  
} crN*eFeW  
[ D.%v~j  
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public synchronized int write(byte[] b,int nStart,int nLen) pb)kN%  
{ '#=0q  
int n = -1; 43]y]/d
o  
try{ SN]g4}K-  
oSavedFile.write(b,nStart,nLen); r)OiiD"  
n = nLen; *")*w> R  
} Js vdC]+  
catch(IOException e) x/wgD'?  
{ xVgm 9s$"c  
e.printStackTrace (); !zllvtK4  
} Cs y,3XG  
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return n; #9Ect@?N0  
} &GkD5
b  
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} t 7o4 aBl"  
- jCj_@n  
6`20  
/* kkWv#,qwU  
**SiteInfoBean.java Pq8oK'z-  
*/ GM?s8yZ<  
package NetFox; 9x|`XAB  
>3@3~F%xAX  
i q oXku  
public class SiteInfoBean { $;'M8L  
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private String sSiteURL; //Site's URL >TY;l3ew  
private String sFilePath; //Saved File's Path dR;N3KwY  
private String sFileName; //Saved File's Name vSC1n8 /  
private int nSplitter; //Count of Splited Downloading File Mgi~j.[  
.xWaS8f  
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public SiteInfoBean() ^D
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{//nSplitter的缺省值为5 ge:a{L  
//default value of nSplitter is 5 ft1#f@b.  
this("","","",5); 3Ovx)qKxd  
} Bv!{V)$  
q?dd5JzZy,  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xPPA8~Dm*  
{ i?;#ZNh  
sSiteURL= sURL; `[g$EXX  
sFilePath = sPath; ()bQmNqmO=  
sFileName = sName; kLF`6ZXtd  
this.nSplitter = nSpiltter; B^r?N-Z A  
)E*f30  
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} XsQ81j.  
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public String getSSiteURL() 6p*X8j3pW  
{ -0#"
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return sSiteURL; ;Vs2e  
} <%Nf"p{K  
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public void setSSiteURL(String value) Z4Dx:m
-  
{ \t&!
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sSiteURL = value; boGdZ2$h4  
} WA~[)S0
  
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{?0'(D7.  
public String getSFilePath() gBv!E9~l  
{ yRyXlZC  
return sFilePath; xb3G,F  
} _ia&|#n  
`G1"&q,i  
g9|OhymB  
public void setSFilePath(String value) cZ|*Zpk  
{ ; F'IS/ttX  
sFilePath = value; W&)f#/M8  
} Nh}-6|M  
*3fl}l  
  8sG?|u  
public String getSFileName() j \jMN*dmV  
{ Qe>_\-f  
return sFileName; Ig}hap]G  
} jI7 x<=  
#p>&|
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public void setSFileName(String value) py:L-5  
{ :rQDA=Ps  
sFileName = value; <efO+X!  
} 9 da=q  
M$%ON>Kq  
9dNkKMc@  
public int getNSplitter() m;l[flQ~  
{ O}zHkcL  
return nSplitter; ]jxyaE&%4  
} qsW&kW~  
mMwV5\(  
7>y]uT@ar  
public void setNSplitter(int nCount) N^$q;%
 
{ mc%. 8i  
nSplitter = nCount; 2=fM\G  
}  94PI  
} En9J7es_  
lf>d{zd5  
9e K~g0m  
/* e:nByzdH0[  
**Utility.java _Sfu8k>):  
*/ =Pw{1m|k  
package NetFox; e8("G[P>  
DZ2gnRg  
[-VH%OM  
public class Utility { gi,7X\`KQ  
yZ,pH1  
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public Utility() r4/b~n+*  
{ aC2Vz9e  
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} g4=1['wW  
#;a+)~3*O  
//线程睡眠 S1^/W-yoc~  
public static void sleep(int nSecond) }Y.YJXum  
{ ai$l7]7  
try{ pP":,8Q{  
Thread.sleep(nSecond); Y+Z+Y)K
  
} ,Ohhl`q(  
catch(Exception e) Yv]vl6<  
{ i=#\`"/  
e.printStackTrace (); bT2c&VPCE  
} 2WH(c$6PWf  
} ,dQ*0XO!  
,= ApnNUgX  
//日志 1q!k#Cliu  
public static void log(String sMsg) kR %,:   
{ jy.L/s  
System.err.println(sMsg); "r@#3T$  
} eC"e v5v  
HN N
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public static void log(int sMsg) #Y7iJPO  
{ 4z5qXI/<m4  
System.err.println(sMsg); dNf9,P_}  
} G`%rnu  
} D? %*L  
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>l)x~Bkf$j  
/* VdM Ksx`r  
**TestMethod.java 2EpQ(G J  
*/ ,)xtl`fc  
package NetFox; 9?ll(5E  
&2 Yo  
N7"cMAs\G  
public class TestMethod { 2*w`l|Sx  
[rcM32  
A2\hmp@A@7  
public TestMethod() kYkA^Aq  
{ ///xx/weblogic60b2_win.exe b*h:e.q  
try{ oe^JDb#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -FZNk}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U9`Co&Z2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +sn0bi/rG  
fileFetch.start(); !1R?3rVQS  
} XkqsL0\  
catch(Exception e){e.printStackTrace ();} 2 oL$I(83  
x'}zNEXI  
^E\4`  
} :^?-bppYW  
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public static void main(String[] args) +7
6ao7d.  
{ \\R<HuTY  
new TestMethod(); W7|nc,i0\  
} y{(Dv} 
 
} %u9Q`  
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