http断点续传简单实现（java)

/* 1fIx@  
**SiteFileFetch.java v%2Dz  
*/ j-**\.4a~  
package NetFox; rf@4
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import java.io.*; @VIY=qh  
import java.net.*; Pn9;&`t  
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public class SiteFileFetch extends Thread { |X XO0  
}xBO;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Hu6Qr  
long[] nStartPos; //开始位置 .IY@Q  
long[] nEndPos; //结束位置 ey9hrRMR  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 mP6}$D  
long nFileLength; //文件长度 gSwHPm%zn  
boolean bFirst = true; //是否第一次取文件 (91ts$jH  
boolean bStop = false; //停止标志 .nVY" C&  
File tmpFile; //文件下载的临时信息 Y7qQ`|  
DataOutputStream output; //输出到文件的输出流 lo6upirZX  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） GKF!GbGR@  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4 Cd5-I  
{ 7_jt =sr  
siteInfoBean = bean; n=~!x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <{;'0> ToM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @oH\r-jsgu  
if(tmpFile.exists ()) .XeZjoJ$z  
{ EJ<L,QH3  
bFirst = false; 7\yh(+kN  
read_nPos(); Wvu1?  
} \zk>cQ  
else F{Yr8(UHA  
{ T;{}bc&I  
nStartPos = new long[bean.getNSplitter()]; L.-qTh^P  
nEndPos = new long[bean.getNSplitter()]; l4taD!WD/  
} jP}Ry=V/  
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} toD!RE  
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public void run() OIw[sum2  
{ bw/mF5AsW  
//获得文件长度 BKI-Dh  
//分割文件 a[j]f
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//实例FileSplitterFetch zx:;0Z:S6>  
//启动FileSplitterFetch线程 6+ptL-Zt<  
//等待子线程返回 c'VCCXe  
try{ F|!=]A<  
if(bFirst) 9mXmghoCO  
{ &#u\@Qze  
nFileLength = getFileSize(); ALO/{:l(  
if(nFileLength == -1) $39TP@?:Z)  
{ Dt7z<1-)l  
System.err.println("File Length is not known!"); Lh-Y5(c o  
} SCMvq?9  
else if(nFileLength == -2) %q;y74  
{ V(LfFO{^>?  
System.err.println("File is not access!"); ZR|s]'  
} :?z@T[-  
else u-jc8W`Zd  
{ AEWrrE
 
for(int i=0;i<nStartPos.length;i++) D(|+z-}M  
{ N`H`\+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <Tbl|9  
} p^w)@^
f  
for(int i=0;i<nEndPos.length-1;i++) rbv  
{ J
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nEndPos = nStartPos[i+1]; 3rN}iSF^  
} L_:~{jV  
nEndPos[nEndPos.length-1] = nFileLength; 99'c\[fd'  
} [K4k7$  
} .)%,R  
~^'t70 :D  
,+v(?5[6  
//启动子线程 x@O)QaBN!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !J{[XT  
for(int i=0;i<nStartPos.length;i++) vg X7B4  
{ z$g__q-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y!S:d
  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), s{X+0_@Q  
nStartPos,nEndPos,i); 4T$jY}U  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6q0)/|,@  
fileSplitterFetch.start(); H0lW gJmi|  
} OU]"uV<(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b
5K"lPr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g~9rt_OV  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :~s*yznf  
nEndPos = " + nFileLength); mxJe\[I  
// fileSplitterFetch[nPos.length-1].start(); &ns??:\+T  
9X#]Lg?b  
ih75C"  
//等待子线程结束 5__B M5|  
//int count = 0; V}2[chbl
 
//是否结束while循环 ?uP5("c  
boolean breakWhile = false; i~<.@&vt  
'< >Q20  
I'n}6D.M  
while(!bStop) U_Mag(^-  
{ vGJw/ij'X  
write_nPos(); E"/k"1@  
Utility.sleep(500); XS&;8 PO  
breakWhile = true; 9MQwc  
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for(int i=0;i<nStartPos.length;i++) Ho&f[T(  
{ ?TW?2+  
if(!fileSplitterFetch.bDownOver) aDLlL?r3  
{ uz3 ?c6b  
breakWhile = false; , :KJ({wM  
break; QGErQ +l  
} 6y?uH;SL  
} r@'
~cF]m  
if(breakWhile) KNP^k$=)3c  
break; q/@r#  
W_/$H_04+  
hQL@q7tUr  
//count++; YF;2jl Nm  
//if(count>4) 4@ny%_/  
// siteStop(); J=O_nup6C  
} [V;u7Z\r-  
W5Jb5  
PuBE=9,  
System.err.println("文件下载结束！"); :Us+u-~  
} SD:Bw0gzrI  
catch(Exception e){e.printStackTrace ();} `!ja0Sq]U  
} y<v-,b*  
!@T~m1L eY  
mpIR: Im  
//获得文件长度 mv$gL  
public long getFileSize() rJ6N'vw>  
{
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int nFileLength = -1; ?g*.
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try{ L0%W;m  
URL url = new URL(siteInfoBean.getSSiteURL()); W ,]Ua
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {[{jlG4H  
httpConnection.setRequestProperty("User-Agent","NetFox"); s!F8<:FRJD  
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int responseCode=httpConnection.getResponseCode(); t""Y -M  
if(responseCode>=400) Nh4&3"g|  
{ 2G:KaQ)  
processErrorCode(responseCode); FiXE0ZI$0q  
return -2; //-2 represent access is error Kj4L PG  
} Yfz`or\@=  
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String sHeader; Q+U" %  
SU~ljAF4  
{G|= pM\'  
for(int i=1;;i++) H:16aaMn(  
{ 6mIRa(6V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f{(D+7e}  
//Utility.log(in.readLine()); J~ z00p`E  
sHeader=httpConnection.getHeaderFieldKey(i); 69odE+-X.  
if(sHeader!=null) o6:]Hvqjr  
{ ~sWXd~\  
if(sHeader.equals("Content-Length")) S[&yO-=p6  
{ oHu7<r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [4PiQyr  
break; q((%sWp  
} zItGoJu  
} %wJ?+D/  
else jnFN{(VH  
break; (~PT(B?  
} O;(
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} V
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catch(IOException e){e.printStackTrace ();} pWoeF=+y]W  
catch(Exception e){e.printStackTrace ();} JY D\VaW  
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Utility.log(nFileLength); Vg"vC  
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return nFileLength; S09Xe_q  
} ]4\6_J&  
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Fa X3@Sd!  
//保存下载信息（文件指针位置） 0v3
8LBH)  
private void write_nPos() v/Xz.?a\jF  
{ }ol<DV  
try{ G98fBw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *E/CNMn=E  
output.writeInt(nStartPos.length); EPEn"{;U  
for(int i=0;i<nStartPos.length;i++) I$fm"N  
{ `TDS4Y  
// output.writeLong(nPos); R]
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output.writeLong(fileSplitterFetch.nStartPos); fQ2U|  
output.writeLong(fileSplitterFetch.nEndPos); lt0byn$vz  
} LdX'V]ITh  
output.close(); R\u5!M$::  
} Dv=pX.Z+  
catch(IOException e){e.printStackTrace ();} XpT~]q}  
catch(Exception e){e.printStackTrace ();} *OY Nx4k  
} (Ii+}Mfp  
e{ZS"e`!  
&&sm7F%  
//读取保存的下载信息（文件指针位置） S$GWY^5}{  
private void read_nPos() H5A7EZq}`  
{ q9$K.=_5  
try{ (^)(#CxO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); AIM
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int nCount = input.readInt(); 'W p~8}i@  
nStartPos = new long[nCount]; mbIHzzW>  
nEndPos = new long[nCount]; A] f^9F@  
for(int i=0;i<nStartPos.length;i++) %^;rYn3  
{ *adwCiB  
nStartPos = input.readLong(); 9%?a\#C  
nEndPos = input.readLong(); -JdNA2P  
} h,i=Y+1  
input.close(); 90a!_8o  
} LH
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catch(IOException e){e.printStackTrace ();} @u-CR8^  
catch(Exception e){e.printStackTrace ();} D.w6/DxaXa  
} '=ydU+X  
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private void processErrorCode(int nErrorCode) #sf1,k5'  
{ Es1T{<G|w  
System.err.println("Error Code : " + nErrorCode); *HQ>tvUh  
} zi+NQ
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edfb7prfTl  
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//停止文件下载 lnrs4s Km  
public void siteStop() }Y3*X:i7  
{ JuRx>F4  
bStop = true; `t]8 [P5  
for(int i=0;i<nStartPos.length;i++) !=vd:,  
fileSplitterFetch.splitterStop(); 7@!3.u1B  
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} _Q\<|~  
}  4{D^ 4G  
//负责部分文件的抓取 ?; tz  
**FileSplitterFetch.java %VO>6iVn  
*/ 9G{#a#Z.  
package NetFox; '.t{\  
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5Ln !>,  
import java.io.*; qo:t"x^  
import java.net.*; 7k#0EhN1>  
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public class FileSplitterFetch extends Thread { LcmZ"M6  
nm@.] "/  
j k/-7
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String sURL; //File URL 249DAjn+  
long nStartPos; //File Snippet Start Position #7naI*O  
long nEndPos; //File Snippet End Position 'F^"+Xi  
int nThreadID; //Thread's ID jlaC: (6  
boolean bDownOver = false; //Downing is over `_<O_  
boolean bStop = false; //Stop identical cIXqnb  
FileAccessI fileAccessI = null; //File Access interface 8AmB0W>e  
6JE_rAab  
E-HK=D&W/  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tx}=c5  
{ xZ`h8  
this.sURL = sURL; -y8>c0u  
this.nStartPos = nStart; U{8x.
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this.nEndPos = nEnd; A=BT2j'l)  
nThreadID = id; )$QZ",&5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 md/NMC \  
} x UTlM  
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C9nCSbGMY{  
public void run() l +#F
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{ E5t /-
4  
while(nStartPos < nEndPos && !bStop) Y?JB%%WWI  
{
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try{ (6X{ &  
URL url = new URL(sURL); .-.b:gdO(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CWS]821;  
httpConnection.setRequestProperty("User-Agent","NetFox");  cjf_,x  
String sProperty = "bytes="+nStartPos+"-"; Kq}-)  
httpConnection.setRequestProperty("RANGE",sProperty); kFQx7m  
Utility.log(sProperty); .N Z  
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InputStream input = httpConnection.getInputStream(); x{$/|_  
//logResponseHead(httpConnection); >$;,1N $bd  
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byte[] b = new byte[1024]; iq3TP5%i  
int nRead; \qB.>f"%p|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zKNac[:  
{ GT-ONwVDq  
nStartPos += fileAccessI.write(b,0,nRead); VN]"[  
//if(nThreadID == 1) UMlvu?u2p1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dIk9C|-.  
} ZtX\E
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Utility.log("Thread " + nThreadID + " is over!"); $!\Z_:  
bDownOver = true; B1z7r0Rm,  
//nPos = fileAccessI.write (b,0,nRead); (4FZK7Fm  
} F[~~fm_  
catch(Exception e){e.printStackTrace ();} 4'H)h'#C  
} C@9K`N[*  
} "Q;Vy t  
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!+n'0{  
//打印回应的头信息 O]Q8&(  
public void logResponseHead(HttpURLConnection con) M~g@y$  
{
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for(int i=1;;i++) 921s'"  
{ :qtg`zM/4  
String header=con.getHeaderFieldKey(i); >9X+\eg-  
if(header!=null) X9ec*x  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); R{{?wr6b$  
Utility.log(header+" : "+con.getHeaderField(header)); XZj3x',;  
else .8]=yPm  
break; L.%zs  
} Kj#h9e  
} <|VV8r93  
M#xol/)h  
Q VWVZ >l  
public void splitterStop() -z>m]YDH  
{ SHqz&2u  
bStop = true; Gc<^b  
} L:Me  
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} z=qxZuFkDs  
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/* JgcMk]|'  
**FileAccess.java c)SQ@B@q  
*//文件访问(定位，写) Q,R|VI6Co  
package NetFox; M&0U@ r-  
import java.io.*; [m9=e-KS$Q  
4&H&zST//m  
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public class FileAccessI implements Serializable{ bl4I4RB  
g7Z3GUCGL  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Hx ojxZwm  
RandomAccessFile oSavedFile; @EUvx  
long nPos; j +Ro?  
/@6T~XY M  
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public FileAccessI() throws IOException CA,2&v"  
{ p}q]G
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this("",0); vJuL+'[i  
}  T_<:  
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public FileAccessI(String sName,long nPos) throws IOException Uk4G9}I  
{ x6 h53R  
oSavedFile = new RandomAccessFile(sName,"rw"); Gvc/o$_  
this.nPos = nPos; b`|,rfq^AZ  
oSavedFile.seek(nPos); NeniQeR  
}
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I<hMS6$<LE  
7:wf!\@I  
public synchronized int write(byte[] b,int nStart,int nLen) 3s_$.  
{ |7b@w;q,D  
int n = -1; OdtS5:L  
try{ q=+wQ[a<  
oSavedFile.write(b,nStart,nLen); HLl"=m1/>  
n = nLen; M|qJZ#{4>  
} Zu/1:8x  
catch(IOException e) Z xR  
{ Qz([\Xx:  
e.printStackTrace (); ;%O>=m'4  
} ='<*mT<  
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return n; iG=XRctgj)  
} }dG>_/3  
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?# )\SQ  
} v\Zq=,+  
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(2r808^2  
/* \7 }{\hY-  
**SiteInfoBean.java 'BNZUuUl  
*/ 3 /LW6W|  
package NetFox; 6?= ^8  
tflUy\H>  
4_o+gG%HaM  
public class SiteInfoBean { "mAMfV0  
V
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private String sSiteURL; //Site's URL }1Pv6L(o)  
private String sFilePath; //Saved File's Path kj'  
private String sFileName; //Saved File's Name ia
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private int nSplitter; //Count of Splited Downloading File }K9Ji]tOK:  
7OLchf  
8V+  
public SiteInfoBean() zA@w[.  
{//nSplitter的缺省值为5 dt(Lp_&v  
//default value of nSplitter is 5 #YB3Ug]z  
this("","","",5); )!d_Td\-  
} bdvVPjGc&  
OCI{)r<O2m  
0Y/k/)Ul]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ou[Wz{  
{ NucLf6  
sSiteURL= sURL; . "`f~s\G  
sFilePath = sPath; 3y-P-NI~=  
sFileName = sName; }62Q{>`  
this.nSplitter = nSpiltter; $"`e^J9!!  
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<"!'>ZUt  
} P;p;o]  
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public String getSSiteURL() 5z"[{#/  
{ Ms=11C  
return sSiteURL; -A1:S'aN-  
} "oT]_WHqo  
lsB.>NlU  
PF:E{_~  
public void setSSiteURL(String value) :6}cczQE|O  
{ W29GM -,K  
sSiteURL = value; @D@'S:3  
} 2w/qH4  
j9 &0/ ~/  
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public String getSFilePath() Kg#s<#h  
{ KPdlg.  
return sFilePath; eEg>EI_U  
} *ZF:LOnU  
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public void setSFilePath(String value) n|!O .+\b  
{ No(S#,vJ;  
sFilePath = value; 5 OF*PBZ  
} u&$1XZ!es  
B \>W  
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public String getSFileName() Q?-uJ1J  
{ scR+F'M  
return sFileName; 30L/-+r1  
} |sV@j_TX  
zjwo"6c>  
x DX_s:A  
public void setSFileName(String value) R5'_il  
{ k1M?6TW&  
sFileName = value; t:qPW<wc  
} RX\@fmK&  
B-aJn8>/  
E0"DHjR  
public int getNSplitter() Xe\,:~  
{ kF7`R4Sz  
return nSplitter; ,4kipJ!,yK  
} (r$QQO)/  
W[.UM
 
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public void setNSplitter(int nCount) 5fud:k  
{ 8^"P'XQ  
nSplitter = nCount; *wK7qS~VB2  
} o1@. <Q+}  
} }7/Ob)O  
q|.K&@_'K  
Y'M}lv$sa  
/* j:'!P<#  
**Utility.java r2>y !Q?  
*/ \DRYqLT`  
package NetFox; O<6!?1|KP  
~aRcA|`  
7\JA8mm  
public class Utility { ~n!7 ?4%U  
C~:!WRCz  
iVb#X#  
public Utility() wq`\p['Q,  
{ _JXb|FIp  
-Hu]2J)  
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} J|[`8 *8  
PVUNi: h  
//线程睡眠 X.<2]V7!  
public static void sleep(int nSecond) ' $X}'u  
{ @)m+b;  
try{ 4p_@f^v~QH  
Thread.sleep(nSecond); HH,G3~EBF  
} p4I6oS`/.  
catch(Exception e) S]&
7  
{ ;gv9J[R  
e.printStackTrace (); t&Z:G<;  
} qf6}\0   
} SZ"^>}zl=  
Gz
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//日志 KoO\<_@";  
public static void log(String sMsg) 3?oj46gP  
{ XW9 [VUW~  
System.err.println(sMsg); y5bELWA  
} jYJfo<  
$)Pmr1==  
*`.4M)Ym~  
public static void log(int sMsg) LjA>H>8%[  
{ &y=~:1&f  
System.err.println(sMsg); 
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} oFUP`p%[  
} (_O_zu8_  
9:jZ3U  
mbRN W  
/* B$cx '_zF  
**TestMethod.java >QM$ NIf@  
*/ wXxk+DV@  
package NetFox; ~",,&>#[K  
)t$|'c}  
.]W A/}  
public class TestMethod { Uw5`zl  
^YG.eT6iG  
1]j_4M14aA  
public TestMethod() &`4v,l^Zi6  
{ ///xx/weblogic60b2_win.exe k,nRC~Irh  
try{ K# dV.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0q ^dpM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +R?d6IjH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _K"X  
fileFetch.start(); 1p9+c~4l:  
} m]NyE
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catch(Exception e){e.printStackTrace ();} p6'wg#15  
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} (j;6}@  
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public static void main(String[] args) H:HJHd"W  
{ L'Fy\K\  
new TestMethod(); A_WtmG_9  
} *FT )`  
} bqDHLoB\1  
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