http断点续传简单实现（java)

/* AA &>6JB{  
**SiteFileFetch.java |x+g5~$  
*/ L}Rsg'U  
package NetFox; {Lg]chJq?  
import java.io.*; x"83[0ib  
import java.net.*; HE{JiAf  
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kdW$>Jqb  
public class SiteFileFetch extends Thread { B }t529Z  
- U Elu4n&  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X"EZpJ'W  
long[] nStartPos; //开始位置 IY40d^x  
long[] nEndPos; //结束位置 ~m6b6Aj@
6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ttd ^jT  
long nFileLength; //文件长度 aESlbH  
boolean bFirst = true; //是否第一次取文件 2kkqPBc_  
boolean bStop = false; //停止标志 FnWN]9  
File tmpFile; //文件下载的临时信息 M;j)F  
DataOutputStream output; //输出到文件的输出流 ]rS:#LK  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $, vXyZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException e.Gjp{  
{ (8td0zq  
siteInfoBean = bean; 9NC?J@&B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <X"_S'O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4d63+iM+}  
if(tmpFile.exists ()) ]9lR:V sw  
{ H#:Aby-d}  
bFirst = false; epGC Ta  
read_nPos(); IcJQC  
} =OamN7V=  
else ZE:!>VXa87  
{ QruclNW{Bv  
nStartPos = new long[bean.getNSplitter()]; ?^gq  
nEndPos = new long[bean.getNSplitter()]; >!3r7L
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} ;)23@6{R%  
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} wBI>H 7A  
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public void run() .r~M7 I  
{ k@|Go)~  
//获得文件长度 ESmWK;7b  
//分割文件 KXT9Wt=  
//实例FileSplitterFetch ni?5h5-  
//启动FileSplitterFetch线程 C17$qdV/  
//等待子线程返回 4vJg"*?  
try{ C+%6N@  
if(bFirst) PrhGp _5  
{ _^@>I8ix  
nFileLength = getFileSize(); ["WWaCcx  
if(nFileLength == -1) LhC
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{ o0 |T<_  
System.err.println("File Length is not known!"); tLzb*U8'1w  
} E RjMe'q4  
else if(nFileLength == -2) k"F\4M  
{ 2#Du5d  
System.err.println("File is not access!"); S0w:R:q}L  
} !:3X{)4  
else V.}3d,Em%]  
{ YB]{gm2  
for(int i=0;i<nStartPos.length;i++) S+bpWA  
{ c&'5r OY~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [w{x+6uX'  
} #+8G`  
for(int i=0;i<nEndPos.length-1;i++) i\dd  
{ ']U<R=5T$  
nEndPos = nStartPos[i+1]; yrG=2{I  
} V/]o':  
nEndPos[nEndPos.length-1] = nFileLength; &3f^]n!@  
} .&2~gA  
} g4^3H
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zuS4N?t`p  
//启动子线程 uc Ph*M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B &e'n
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for(int i=0;i<nStartPos.length;i++) *~
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{ |f3 :9(p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cRv#aV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7;9 Jn  
nStartPos,nEndPos,i); |3G;Rh9w,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vg8Yc  
fileSplitterFetch.start(); }"M5"?  
} k]rc -c-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [Om,Q<
  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a5?Yh<cJ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a= (vS  
nEndPos = " + nFileLength); nL+y"O  
// fileSplitterFetch[nPos.length-1].start(); 6z2%/P-'  
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.u:aX$t+  
//等待子线程结束 :6J&%n  
//int count = 0; R(f6uO!m  
//是否结束while循环 Ch_eK^ g1  
boolean breakWhile = false; RMHJI6?LB  
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}H:wgy`  
while(!bStop) LZDJ\"a-  
{ Y)2#\ F  
write_nPos(); (qzBy \\p  
Utility.sleep(500); '7 t:.88  
breakWhile = true; 2  Z
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for(int i=0;i<nStartPos.length;i++) ;_#<a*f  
{ M9~6ry-_  
if(!fileSplitterFetch.bDownOver) 1
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{ (0["|h32,  
breakWhile = false; JHa\"h  
break; :,V&P_  
} Jwpc8MQ  
} %+oqAYm+s  
if(breakWhile) fR]KXfZ  
break; KNjU!Z/4  
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!oYNJE Y7  
//count++;  9XhcA  
//if(count>4) 3_"tds <L  
// siteStop(); o,RiAtdk  
} w+$~ds  
4UHviuOo8  
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System.err.println("文件下载结束！"); 1#9
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} S$ k=70H  
catch(Exception e){e.printStackTrace ();} <m~{60{  
} zKT4j1h  
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J,J6bfR/  
//获得文件长度 CA5T3J@vAQ  
public long getFileSize() v.hQ9#:  
{ $HCgawQ  
int nFileLength = -1; (4|R}jv  
try{ \h?6/@3ob  
URL url = new URL(siteInfoBean.getSSiteURL()); @VQ<X4Za  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l{*Ko~g  
httpConnection.setRequestProperty("User-Agent","NetFox"); _*Ej3=u  
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&+3RsIlW  
int responseCode=httpConnection.getResponseCode(); *fz#B/_o  
if(responseCode>=400) 10xza=a  
{ a(LtiO  
processErrorCode(responseCode); FKUo^F?z  
return -2; //-2 represent access is error BjGfUQ  
} q:=jv6T#  
GT\yjrCd  
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String sHeader; Q%524%f$  
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}X. Fm'`  
for(int i=1;;i++) @^/aS;B$>  
{ ^7yaMB!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hkdF  
//Utility.log(in.readLine()); FY`t7_Y?GV  
sHeader=httpConnection.getHeaderFieldKey(i); $%4<q0-  
if(sHeader!=null) CbpzYv32  
{ Qq'e#nI@  
if(sHeader.equals("Content-Length")) GWLdz0`2_  
{ =~5N/!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5H1N]v+  
break; _l+C0lQ
l=  
} tEt
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} w OOu/Y  
else P-<1vfThH  
break;  n(|rs  
} Ow(aRWUZD_  
} =zu;npM  
catch(IOException e){e.printStackTrace ();} C_JO:$\rE  
catch(Exception e){e.printStackTrace ();}
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Utility.log(nFileLength); {rK]Q! yj  
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return nFileLength; T+B8SZw#}!  
} q|0l>DPRp  
K]uH7-YvL/  
OMM5ALc(F  
//保存下载信息（文件指针位置） 5=I"bnIU  
private void write_nPos() 62MQ+H  
{ wqT9m*VK  
try{ \hn$-'=4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 78r0K 5=  
output.writeInt(nStartPos.length); Xvoz4'Gme  
for(int i=0;i<nStartPos.length;i++) 1Wiz0X/  
{ wS+!>Q_]w  
// output.writeLong(nPos); kKjcW` [  
output.writeLong(fileSplitterFetch.nStartPos); iSUu3Yv,_m  
output.writeLong(fileSplitterFetch.nEndPos); UWhJkJsX  
} 'IT]VRObP  
output.close(); ~ch%mI~  
} ,fq
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catch(IOException e){e.printStackTrace ();}
&=kb>*  
catch(Exception e){e.printStackTrace ();} }"SqB{5e(  
} wX_~H*m?  
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7WUvO  
//读取保存的下载信息（文件指针位置） GgnR*DVP$  
private void read_nPos() C|2|OTtQ  
{ &,=FPlTC=  
try{ e6bh,BwgQq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); BoST?"&}'  
int nCount = input.readInt(); W-gu*iZ6&  
nStartPos = new long[nCount]; DycXJ3eQ  
nEndPos = new long[nCount]; HVhP |+  
for(int i=0;i<nStartPos.length;i++) ?>iU
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{ /h{Rf,H  
nStartPos = input.readLong(); wOCAGEg  
nEndPos = input.readLong(); gFrNk Uqp  
} z+{+Q9j  
input.close(); }/h&`0z`  
} BvH?d]%  
catch(IOException e){e.printStackTrace ();} 8e^uKYR<  
catch(Exception e){e.printStackTrace ();} k<MQ  
} 7S^G]g!x  
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private void processErrorCode(int nErrorCode) 0 q1x+  
{ ,,+4d :8$  
System.err.println("Error Code : " + nErrorCode); 8ICV"8(  
} 6GPI gPL,  
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X/90S2=P  
//停止文件下载 0xO*8aKT  
public void siteStop() nm
& pn*1  
{ MB $aN':  
bStop = true; <VQ)}HW;k  
for(int i=0;i<nStartPos.length;i++) 1r_V$o$  
fileSplitterFetch.splitterStop(); -%gEND-AP  
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} A0U
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} 2ZEGE+0  
//负责部分文件的抓取 erbk(  
**FileSplitterFetch.java \G7F/$
g  
*/ =6O*AJ  
package NetFox; -u
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8D,*_p  
s;=C&N5g  
import java.io.*; -u4")V>  
import java.net.*; +4Pes  
R dwt4A+  
#^Pab^Y3r-  
public class FileSplitterFetch extends Thread { EpyMc+.Ze'  
-{8K/!  
#.[eZ[  
String sURL; //File URL KX7fgC  
long nStartPos; //File Snippet Start Position B2P@9u|9  
long nEndPos; //File Snippet End Position Hk@Gkx_  
int nThreadID; //Thread's ID K
1BBCe  
boolean bDownOver = false; //Downing is over 5%e+@X;j  
boolean bStop = false; //Stop identical Gyy4zK  
FileAccessI fileAccessI = null; //File Access interface k4hk* 0Jq  
r 1jt~0&K  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ox&G  [  
{ D>@NYqMF  
this.sURL = sURL; 5oSp/M  
this.nStartPos = nStart; :$,MAQ'9  
this.nEndPos = nEnd; o|xZ?#^h  
nThreadID = id; dFDf/tH  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 VN`fZ5*d~  
} rQ_@q_B.  
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public void run() X<Z(,B  
{ 3X11Gl  
while(nStartPos < nEndPos && !bStop) R3l{.{3p2  
{ zxCx
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try{ ZV+tHgzlv5  
URL url = new URL(sURL); :v;U7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~IjID
 
httpConnection.setRequestProperty("User-Agent","NetFox"); `&7tADFB  
String sProperty = "bytes="+nStartPos+"-"; -fmJkI  
httpConnection.setRequestProperty("RANGE",sProperty); 7>BfHb  
Utility.log(sProperty); w4Df?)Z  
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InputStream input = httpConnection.getInputStream(); la_c:#ho  
//logResponseHead(httpConnection); C!Srv7  
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byte[] b = new byte[1024]; megTp  
int nRead; AH5;6Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) htR.p7&Tn  
{ p/VVb%  
nStartPos += fileAccessI.write(b,0,nRead); u;-fG9xs  
//if(nThreadID == 1) xlu4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n+hL/aQ+  
} 0V(}Zj>  
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"O<ETHd0  
Utility.log("Thread " + nThreadID + " is over!"); 2~?E'  
bDownOver = true; ~"#HHaBO#  
//nPos = fileAccessI.write (b,0,nRead); L*[3rqER  
} Yg3nT:K_Y&  
catch(Exception e){e.printStackTrace ();} W_JO~P  
} y^`JWs,  
} Y.]$T8  
X_hDU~5{wC  
!Kg']4  
//打印回应的头信息 ?\,^>4x?  
public void logResponseHead(HttpURLConnection con) -[ gT}{k!  
{ BDWbWA 6  
for(int i=1;;i++) 'u;O2$  
{ _3yG<'f[Y  
String header=con.getHeaderFieldKey(i); Z9+fTT  
if(header!=null) H4AT>}ri  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); tLa%8@;'$  
Utility.log(header+" : "+con.getHeaderField(header)); |oXd4  
else ZDbe]9#Xh  
break; z_fjmqa?  
} -HQbvXAS  
} {DQ%fneN4  
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public void splitterStop() [%N?D#;  
{ &tAYF_}  
bStop = true; -R:_o1"  
} cS9jGD92  
@|DQZt  
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} .Lna\Bv  
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%8tE*3iUF  
/* @|vH5Pi  
**FileAccess.java }\?9Prsd  
*//文件访问(定位，写) -;L'Jb>s76  
package NetFox; , i5_4  
import java.io.*; WJnGF3G>  
@CmKF  
u/u(Z&  
public class FileAccessI implements Serializable{ c Pf_B=  
#6<1 =I'j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 A,cXN1V  
RandomAccessFile oSavedFile; qGV_oa74  
long nPos; V>`ANZ4  
Fds 11 /c7  
=oq8SL?bJ*  
public FileAccessI() throws IOException lt&(S)  
{ SULFAf<  
this("",0); daI_@kY"  
} Z%qtAPd  
3>aEP5  
bPU i44P  
public FileAccessI(String sName,long nPos) throws IOException r_#
dh  
{ \}?X5X>  
oSavedFile = new RandomAccessFile(sName,"rw"); $0E+8xE  
this.nPos = nPos; }Pg}"fb^  
oSavedFile.seek(nPos); m"iA#3l*=  
} :]@c%~~!&  
I'BhN#GhX  
S-7
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public synchronized int write(byte[] b,int nStart,int nLen) _NsEeKU  
{ K8sRan[4}  
int n = -1; _V-KyK  
try{ p/HDG ^T:u  
oSavedFile.write(b,nStart,nLen); 2H)4}5H  
n = nLen; 7PX`kI  
} , ,{UGe3  
catch(IOException e) 1 &9|~">{C  
{ @a?7D;+<  
e.printStackTrace (); 5dj@N3ZX7;  
} a,c!#iyl3  
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return n; WR"D7{>tw  
} YOD.y!.zq7  
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} a4__1N^Qj  
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/* tTLg;YjN  
**SiteInfoBean.java 05`"U#`:  
*/ lb-1z]YwQ  
package NetFox; l?U=s7s0?  
+nDy b  
[8i)/5D4  
public class SiteInfoBean { V*uE83x1  
|1~n<=`Z  
'p&,'+x  
private String sSiteURL; //Site's URL 27e!KG[&  
private String sFilePath; //Saved File's Path YB5"i9T2  
private String sFileName; //Saved File's Name g"ev
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private int nSplitter; //Count of Splited Downloading File -)`_w^Ox  
5QMra5Nk  
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public SiteInfoBean() L=4+rshl!_  
{//nSplitter的缺省值为5 !mmMAsd,  
//default value of nSplitter is 5 }'$PYAf6  
this("","","",5); KhHFJo[8sf  
} $')C&  
y2G Us&09  
vjuFVJwL  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 50^ux:Uv+N  
{  p+h$]CH  
sSiteURL= sURL; D(AH3`*|#  
sFilePath = sPath; 6}"c4^k6  
sFileName = sName; dI{DiPho  
this.nSplitter = nSpiltter; Q5+1'mzAB  
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} f2i:I1 p("  
08`|C)Z!  
#Vq9 =Q2  
public String getSSiteURL() :aesG7=O  
{ E#B-JLMGl  
return sSiteURL; ?l0eU@rwQ  
} Hc)z:x;Sj  
{{?g%mQ6  
 )(G9[DG  
public void setSSiteURL(String value) HC%Hbc~S_Q  
{ .A2$C|a*  
sSiteURL = value; =&WIa#!=  
} 'a['lF  
5?
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public String getSFilePath() v`HER6  
{ nI\6aG?`  
return sFilePath; Y}:~6`-jj  
} k{}> *pCU  
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public void setSFilePath(String value) b2m={q(s  
{ Zse&{  
sFilePath = value;
$9)os7H7  
} jf~](TK  
k?+ 7%A]  
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public String getSFileName() Yj/afn(Jt  
{ p)y5[HX  
return sFileName; j/O~8o&  
} i5VZ,E^E  
)6OD@<r{  
-50DGA,K6  
public void setSFileName(String value) ;CYoc4e  
{ _fHC+lwN  
sFileName = value; B/twak\  
} bdg6B7%Q  
^#9385  
X0lPRk53(  
public int getNSplitter() $%y q[$^  
{ +V3mF_s|z  
return nSplitter; )^>LnQ_u  
} 7'G;ijx  
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j#l=%H  
public void setNSplitter(int nCount) t#k]K]  
{ z*\_+u~u  
nSplitter = nCount; 7oE0;'  
} 2}hJe+#v  
} A3jxjQ  
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/* T+kV~ w{  
**Utility.java fkA+:j~z_  
*/ mq`/nAmt  
package NetFox; 6_CP?X+T  
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public class Utility { sy: xA w  
4Yj1Etq.E  
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public Utility() Ez3fL&*  
{ {w@qFE'b  
o`bch?]  
F-_u/C]  
} d>QFmsh-  
HBlk~eZ  
//线程睡眠 50,'z?-_  
public static void sleep(int nSecond) !nvwRQ  
{ FY1iY/\Cn  
try{ E }L Hp  
Thread.sleep(nSecond); `|dyT6V0I_  
} L)e"qC_-  
catch(Exception e) HQqFrR  
{ U0x A~5B  
e.printStackTrace (); YvR bM  
} r/YJ,2!  
} ij"~]I  
]PXM;w  
//日志 GEBSUv
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public static void log(String sMsg) UcRP/LR%C  
{ A_xC@$1e<  
System.err.println(sMsg); #N|\7(#~u  
} OF-k7g7  
~tDYo)hH8  
aJu&h2G  
public static void log(int sMsg) 7sot?gF  
{ vsY?
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System.err.println(sMsg); WtT;y|W  
} 8=8hbdy;  
} kf, &t   
Iy<>-e"|  
>jm(2P(R   
/* afm\Iv[*  
**TestMethod.java LEb$Fd  
*/ s,z~qL6&  
package NetFox; 19!?oeOU  
1"h"(dA  
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public class TestMethod { q m3\)9C  
b1&tk~D  
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public TestMethod() ]Q^)9uE\D  
{ ///xx/weblogic60b2_win.exe Cf% qa
p#  
try{ YT\`R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;%e&6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); G|6qL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 77>oQ~q  
fileFetch.start(); 8mI(
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} 0At0`Q#  
catch(Exception e){e.printStackTrace ();} @8d 3  
inut'@=G/  
RSX27fb4  
} #;[G>-tC  
i]8O?Ab>?  
%OQdUH4x  
public static void main(String[] args) X9x`i  
{
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new TestMethod(); ?cU,%<r  
} |]\zlH"w  
} fY<#KM6X  
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