http断点续传简单实现（java)

/* bnZ H  
**SiteFileFetch.java [1e]_9)p  
*/ 5zz">-Q !  
package NetFox; |nBs(>b  
import java.io.*; /[A#iTe  
import java.net.*; W3jwc{lj  
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public class SiteFileFetch extends Thread { 5?m4B:W  
"s}Oeu[  
v.hQ9#:  
SiteInfoBean siteInfoBean = null; //文件信息Bean [eFJ+|U9  
long[] nStartPos; //开始位置 VaA.J  
long[] nEndPos; //结束位置 O8~RfB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _*Ej3=u  
long nFileLength; //文件长度 7^syu;DT9Y  
boolean bFirst = true; //是否第一次取文件
v#?;PyeF  
boolean bStop = false; //停止标志 >[;L.  
File tmpFile; //文件下载的临时信息 BjGfUQ  
DataOutputStream output; //输出到文件的输出流 c Qe3  
0rvBjlFT  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /vC!__K9:  
public SiteFileFetch(SiteInfoBean bean) throws IOException \/b[V3<"  
{ 2#ZqGf.'v  
siteInfoBean = bean; &G?"I%Vw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n6G&c4g<"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2@IL  n+#  
if(tmpFile.exists ()) %cBOi_}}~  
{ iNc!zA4  
bFirst = false; N6`U)=2o>h  
read_nPos(); iCCe8nK  
} -/2B fIq  
else @$iZ9x6t  
{ = 5[%%Lf  
nStartPos = new long[bean.getNSplitter()]; nw_s:  
nEndPos = new long[bean.getNSplitter()]; 5~ZzQG  
} \(--$9  
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{+GR/l\!#  
} 5{#s<%b.  
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:dNJ2&kJ  
public void run() 3V7WIj<  
{ x6*y$D^B  
//获得文件长度 )FPn_p#3]  
//分割文件 v+}${h9  
//实例FileSplitterFetch 1Wiz0X/  
//启动FileSplitterFetch线程 <sw=:HU  
//等待子线程返回 HA7%8R*.2i  
try{ i=1crJ:  
if(bFirst) 'Ebjn>"  
{ JVxja<43  
nFileLength = getFileSize();
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if(nFileLength == -1) 7WUvO  
{ a>rDJw:  
System.err.println("File Length is not known!"); 8!HB$vdw7  
} C/H;|3.X  
else if(nFileLength == -2) $rTb'8  
{ 2i;ox*SfpU  
System.err.println("File is not access!"); 0igB pHS  
} L[
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else %n GjP^  
{ t%J1(H  
for(int i=0;i<nStartPos.length;i++) $4~Z]-38#A  
{ 4T;<`{]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); HTz`$9  
} Ok|Dh;1_  
for(int i=0;i<nEndPos.length-1;i++) tbiM>qxB  
{ X/90S2=P  
nEndPos = nStartPos[i+1]; 3"< 0_3?W  
} ipl,{  
nEndPos[nEndPos.length-1] = nFileLength; 1r_V$o$  
} .Gvk5Wn  
} Hb::;[bm:  
2ZEGE+0  
)J0h\ky  
//启动子线程 &6 <a<S  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \v5;t9uBZ  
for(int i=0;i<nStartPos.length;i++) `'sD(e  
{ "P54|XIJ\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #^Pab^Y3r-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), X{H
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nStartPos,nEndPos,i); Crg'AB?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y+w,j]  
fileSplitterFetch.start(); tl\<:8pI"  
} ciiI{T[Z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4OQ,|Wm4G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _ZFEo< `'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;b~\[  
nEndPos = " + nFileLength); CswKT9  
// fileSplitterFetch[nPos.length-1].start(); lw[c+F7  
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X(X[v]  
//等待子线程结束 ;RX u}pd  
//int count = 0; qP<D9k>  
//是否结束while循环 _oCNrjt9  
boolean breakWhile = false; V+y"L>K  
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while(!bStop) dt,Z^z+"E  
{ uf9&o#  
write_nPos(); _8 |X820  
Utility.sleep(500); f$:SacF  
breakWhile = true; FE&:?  
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for(int i=0;i<nStartPos.length;i++) (IVhj^dQm  
{ i2c|_B  
if(!fileSplitterFetch.bDownOver) -X~|jF  
{ RK &>!^  
breakWhile = false; vno/V#e$WX  
break;  e
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} ^N|8 B?Vg  
} v[^8_y}A`  
if(breakWhile) ~"#HHaBO#  
break; L*[3rqER  
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W_JO~P  
//count++; 4fC:8\A  
//if(count>4) ?SElJ?Z  
// siteStop();
`HkNO@N[  
} 3u$1W@T(  
CssE8p>"F  
[i ~qVn2vT  
System.err.println("文件下载结束！"); ?zm]KxIC  
} 6{HCF-cQd  
catch(Exception e){e.printStackTrace ();} u"*DI=pwb  
} Wu/#}Bw#  
#IM.7`I  
& rab,I"  
//获得文件长度 1VlU'qY  
public long getFileSize() fM4B.45j  
{ I*3}e
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int nFileLength = -1; y"q>}5  
try{ _7<{+Zzm  
URL url = new URL(siteInfoBean.getSSiteURL()); jxkjPf?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s{yw1:  
httpConnection.setRequestProperty("User-Agent","NetFox"); %}VH5s9\  
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{ptHk<K:)  
int responseCode=httpConnection.getResponseCode(); @e GBF Ns  
if(responseCode>=400) aYb97}kI  
{ DJ:'<"zH7  
processErrorCode(responseCode); poxF`a6e+  
return -2; //-2 represent access is error G_S>{<[  
} G#7(6:=;,`  
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3EICdC  
String sHeader; /z*Z+OT2  
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for(int i=1;;i++) KRC"3Qt  
{ znwKwc8,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Nb`qM]&  
//Utility.log(in.readLine()); (;},~( 2B  
sHeader=httpConnection.getHeaderFieldKey(i); IUFc_uL@\  
if(sHeader!=null) @nY]S\if  
{ F9u?+y-xb  
if(sHeader.equals("Content-Length")) 5MAfuHq^  
{ ^F+7<$2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TjEXR$:<  
break; =#S.t:HQ*  
} JN|6+.GG  
} 1d<Uwb>  
else aY>v  
break; R;c9)>8L  
} kygw}|, N  
} PU/<7P*  
catch(IOException e){e.printStackTrace ();} 96(Mu% l  
catch(Exception e){e.printStackTrace ();} 6^[4.D  
|2u=3#Jp  
?!U[~Gq  
Utility.log(nFileLength); sjg`4^!wDD  
| :-i[G?n  
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return nFileLength; nOGTeKjEJ  
} jRS{7rx%MH  
#;j:;LRU  
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//保存下载信息（文件指针位置） Ec@n<KK#  
private void write_nPos() 2+ cs^M3  
{ Szgo@x$^  
try{ 6p)AQTh>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q,&Li+u|  
output.writeInt(nStartPos.length); MxIa,M<  
for(int i=0;i<nStartPos.length;i++) QS&B"7;g  
{ rTIu'  
// output.writeLong(nPos); 6(f'P_*  
output.writeLong(fileSplitterFetch.nStartPos); Yg^ &4ZF  
output.writeLong(fileSplitterFetch.nEndPos); Y#ZgrziYM  
} [7FG;}lB-  
output.close(); \:WWrY8&  
} qJrT  
catch(IOException e){e.printStackTrace ();} c>B1cR  
catch(Exception e){e.printStackTrace ();} R}M ;, G  
} IT_I.5*A2  
:
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//读取保存的下载信息（文件指针位置） I4X9RYB6c  
private void read_nPos() "%gsGtS  
{ tNi>TkC}`  
try{ `x9Eo4(
/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); J, 9NVw$  
int nCount = input.readInt(); ##7y|AwK  
nStartPos = new long[nCount]; GkIY2PD  
nEndPos = new long[nCount]; =1l6(pJ  
for(int i=0;i<nStartPos.length;i++) rG-T Dm  
{ .:r~?$(  
nStartPos = input.readLong(); _qxI9Q}<"  
nEndPos = input.readLong(); MY^{[#Q  
} (j&:  
input.close(); \!-BR0+y;  
} "+F'WCJ-(*  
catch(IOException e){e.printStackTrace ();} y>P+"Z.K%}  
catch(Exception e){e.printStackTrace ();} $oK&k
}Q  
} *|fF;-#v  
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private void processErrorCode(int nErrorCode) g"!(@]L!@  
{ "?I#!t%'  
System.err.println("Error Code : " + nErrorCode); }X&rJV  
} <-umeY"n>  
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//停止文件下载 w7V\_^&Id  
public void siteStop() 7Q}pKq]P  
{ 6l]X{A.  
bStop = true; :aesG7=O  
for(int i=0;i<nStartPos.length;i++) |1U_5w  
fileSplitterFetch.splitterStop(); zfeT>S+  
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} +xFn~b/  
} *;o%*:  
//负责部分文件的抓取 6p9fq3~7Y  
**FileSplitterFetch.java HEF e?
 
*/ g'(bk@<BP  
package NetFox; fE-R(9K  
{>f"&I<xw  
1@F-t94I  
import java.io.*; ZEP?~zV\A  
import java.net.*; HL38iXQ( 3  
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public class FileSplitterFetch extends Thread { $Habhw  
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String sURL; //File URL 3 jZMXEG)  
long nStartPos; //File Snippet Start Position
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long nEndPos; //File Snippet End Position 9L=mS  
int nThreadID; //Thread's ID B*(]T|ff<  
boolean bDownOver = false; //Downing is over p)y5[HX  
boolean bStop = false; //Stop identical j/O~8o&  
FileAccessI fileAccessI = null; //File Access interface i5VZ,E^E  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^3;B4tj[  
{ -*C WF|<G  
this.sURL = sURL; IOy0WHl|  
this.nStartPos = nStart; &9L4 t%As  
this.nEndPos = nEnd; /( Wq  
nThreadID = id; zBF~:Uc`B  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ge~@}&#iO@  
} )^>LnQ_u  
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public void run() NAGM3{\5v$  
{ wPlM= .Hq?  
while(nStartPos < nEndPos && !bStop) jm}CrqU  
{ QJ|@Y(KV0  
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try{ &."$kfA+  
URL url = new URL(sURL); sh<Q2X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IPQRdBQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); a>wCBkD  
String sProperty = "bytes="+nStartPos+"-"; Ep7MU&O0iK  
httpConnection.setRequestProperty("RANGE",sProperty); 6d-\+t8  
Utility.log(sProperty); 4&iQ
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InputStream input = httpConnection.getInputStream(); 2Ez<Iw  
//logResponseHead(httpConnection); E9:@H;Gc  
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a  
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byte[] b = new byte[1024]; g6GkA.!X$  
int nRead; %~u]|q<{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^P)f]GQx  
{ D|-]<r1"  
nStartPos += fileAccessI.write(b,0,nRead); L5&M@YTH  
//if(nThreadID == 1) 1-2hh)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n(:<pz  
} mUYRioNj  
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Utility.log("Thread " + nThreadID + " is over!"); %Bs. XW,  
bDownOver = true; 2~4:rEPJ:  
//nPos = fileAccessI.write (b,0,nRead); AZj&;!}  
} C/kf?:j  
catch(Exception e){e.printStackTrace ();} ~iL^KeAp   
} uo9#(6
 
} Q]ersA8 V>  
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//打印回应的头信息 g`Z=Y7jLH  
public void logResponseHead(HttpURLConnection con) RRL{a6(?  
{ @!8aZB3odt  
for(int i=1;;i++) TEtmmp0OD  
{ z0z@LA4k6@  
String header=con.getHeaderFieldKey(i); Qb536RpcTY  
if(header!=null) E&M(QX5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); c;l!i-  
Utility.log(header+" : "+con.getHeaderField(header)); X
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else UP
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break; `m,4#P-kj  
} (MwRe?Ih  
} ,}oAc  
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public void splitterStop() cgnNO&  
{ {}O~
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bStop = true; P}R:o  
} -n
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} Aoe\\'O|V  
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 :eN&wQ5q  
/* tsXKhS;/w  
**FileAccess.java + G@N  
*//文件访问(定位，写) zl
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package NetFox; c*bvZC^6  
import java.io.*; je] DR~  
Myq8`/_  
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public class FileAccessI implements Serializable{ `4Yo-@iVP  
s9- qR_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ejN/U{)jK'  
RandomAccessFile oSavedFile; u`bD`kfT>  
long nPos; 'eM0i[E+`  
J
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#]` uH{  
public FileAccessI() throws IOException fBSa8D3}`  
{  a"Qf  
this("",0); @]3\*&R}  
} XwH>F7HPe  
dC=[o\  
t7=D$ua  
public FileAccessI(String sName,long nPos) throws IOException 2Tp2{"sB>A  
{ DiJLWXs  
oSavedFile = new RandomAccessFile(sName,"rw"); N J3;[qJ  
this.nPos = nPos; VotC YJ  
oSavedFile.seek(nPos); DiFLat]X  
} D|uvgu2  
GppCrQ%Ra|  
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public synchronized int write(byte[] b,int nStart,int nLen) N' hT
  
{ lY%I("2=  
int n = -1; N>mW64_H)  
try{ .j}]J:{%  
oSavedFile.write(b,nStart,nLen); ORM>|&  
n = nLen; YWZ;@,W  
} %>KbaM1b  
catch(IOException e) pMfb(D"  
{ wQxI({k@  
e.printStackTrace (); 1@]&i
Z]  
} )[rVg/m  
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return n; qBEp |V  
} Tzq@ic#!B  
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} 8Qvs\TY  

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/* PK|-2R"M
  
**SiteInfoBean.java 35\ |#2qw6  
*/ W+h2rv  
package NetFox; <-VBb[M#  
s.J4&2Q  
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public class SiteInfoBean { rA~f68h|  
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7;jD>wp9D  
private String sSiteURL; //Site's URL "O34 E?ql.  
private String sFilePath; //Saved File's Path \|=6<ZY:  
private String sFileName; //Saved File's Name oe<i\uX8z  
private int nSplitter; //Count of Splited Downloading File u\\t~<8  
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public SiteInfoBean() e]4$H.dP  
{//nSplitter的缺省值为5 2<D| {  
//default value of nSplitter is 5 X^\D"fmE.  
this("","","",5); P6+ B!pY  
} nI:M!j5s`  
!"^Zr]Qt+\  
">}6i9o  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) JR!-1tnc  
{ jTa\I&s,A  
sSiteURL= sURL; 4H{t6t@-:  
sFilePath = sPath; 7^d
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sFileName = sName; tZ_'>7)  
this.nSplitter = nSpiltter; ale'-V)5  
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} VN`.*B|9[  
2KLMFI.F  
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public String getSSiteURL() U,g8:M xHK  
{ #Y7jNrxE
  
return sSiteURL; '1mk;%  
} O= S[n  
VLXA6+  
\.LjA_  
public void setSSiteURL(String value) "J(M.Y  
{ ~ZKJ:&f  
sSiteURL = value; eF+F"|1h  
} 'f( CN3.!  
X1#Ar)  
s~M$Wo8  
public String getSFilePath() 8~Cmn%  
{ u)@:V)z  
return sFilePath; $qD\ku;'  
} m23"xnRB  
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~F"S]  
public void setSFilePath(String value) j iKHx_9P  
{ o/Ismg-p  
sFilePath = value; 'z|Da&d P  
} UoxlEec  
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public String getSFileName() :\^b6"}8  
{ D ,kxB~  
return sFileName; #`iEbiSq  
} Y 9$jJ1V  
~1O|4mssS  
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public void setSFileName(String value) '+9<[]  
{ DzVCEhf  
sFileName = value; VrIN.x  
} <^YvgQ,m  
Yq ]sPE92  
7_\G|Zd  
public int getNSplitter() !v8
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{ $Cz2b/O  
return nSplitter; s#^0[ Rt  
} tVG;A&\,6  
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7yE\,  
public void setNSplitter(int nCount) [* <x)  
{ S~/2Bw!2  
nSplitter = nCount; :E9pdx+  
} /EjXyrn2  
} coXg]bUKo  
?t'V5$k\  
Im6gWDdq@6  
/* v0C+DKi  
**Utility.java (OiV IH  
*/ NK0'\~7&  
package NetFox; f&<+45JI  
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public class Utility { j|KDgI<0  
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public Utility() w[X-Q+7p(t  
{ }u;K<<h:  
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LK}
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} %`i*SF(gV  
3dN`Q:1R9  
//线程睡眠 p7QZn.,=u  
public static void sleep(int nSecond) /?;'y,(Q  
{ (_ G>dP_  
try{  E0!d c  
Thread.sleep(nSecond); [q|W*[B:@  
} C>|.0:[%  
catch(Exception e) h(=<-p@  
{ ==Egy:<:Q  
e.printStackTrace (); '&cH,yc;b  
} lp(2"$nQ  
} '~Y@HRVL@|  
_:[@zxT<x  
//日志 xt|^~~ /  
public static void log(String sMsg) ,lH }Ba02F  
{ wN.
S]  
System.err.println(sMsg); ~u&gU1}  
} YZ>L_$:q  
x$q}lJv_  
z)M#9oAM  
public static void log(int sMsg) 'I>USl3hI  
{ PA'&]piPl:  
System.err.println(sMsg); |$\K/]q-  
} 1["i,8zB  
} w=#'8ZuU  
sJZ2e6?n  
[W3X$r~-  
/* wQG?)aaM  
**TestMethod.java ,ayEZ#4.m  
*/ !=eNr<:V.  
package NetFox; r#OPW7mhE  
.e7tq\k  
i.^ytbH  
public class TestMethod { Rq|6d M6H  
) A:h  
b- - tl@H  
public TestMethod() V;eaQ  
{ ///xx/weblogic60b2_win.exe Il [~  
try{ !JXiTI!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5, $6mU#=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); OMK,L:poC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oMN<jAU.  
fileFetch.start(); v#x`
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} <8}FsRr;J  
catch(Exception e){e.printStackTrace ();} eN<L)a:J_  
H
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4Kch=jt4#  
} [2-n*a(q  
*k7BE_&*0Z  
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public static void main(String[] args) ~vA{I%z5~  
{ !S=YM<Ad  
new TestMethod(); \2kLj2!  
} &%rM|  
} l Xa/5QKC  
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