http断点续传简单实现（java)

/* dnix:'D1  
**SiteFileFetch.java ^ZR8s^X  
*/ O"qR}W  
package NetFox; gNTh% e  
import java.io.*; 1f<RyAE?5  
import java.net.*; cu<y8 :U<  
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public class SiteFileFetch extends Thread { q=njKC  
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SiteInfoBean siteInfoBean = null; //文件信息Bean A9t8`|1"%H  
long[] nStartPos; //开始位置 M</Wd{.g"  
long[] nEndPos; //结束位置 p/N62G  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +SyUWoM  
long nFileLength; //文件长度 b]w[*<f?  
boolean bFirst = true; //是否第一次取文件 0:. 6rp  
boolean bStop = false; //停止标志 ":V%(c  
File tmpFile; //文件下载的临时信息 B.}cB'|  
DataOutputStream output; //输出到文件的输出流 V(r`.75  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 
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public SiteFileFetch(SiteInfoBean bean) throws IOException S4)A6z$  
{ kAe
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siteInfoBean = bean; KYf;_C,$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fL2^\dB;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !f`5B( @  
if(tmpFile.exists ()) [$;,Ua-mt  
{ W=3? x  
bFirst = false; V;k#})_-  
read_nPos(); o~;M"  
} @*SA$9/l  
else 2Q}7fht  
{ z#RuwB+  
nStartPos = new long[bean.getNSplitter()]; 2qlIy  
nEndPos = new long[bean.getNSplitter()]; {a. <`  
} {gw[%[ZM  
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} rfc|`*m}0  
K>$qun?5  
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public void run() u(AA`
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{ ^iuo^
2+  
//获得文件长度 cN5"i
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//分割文件 wh*:\_!0\  
//实例FileSplitterFetch ZL,6_L/  
//启动FileSplitterFetch线程 t|_{;!^  
//等待子线程返回 FD))'!>  
try{  jC4O`  
if(bFirst) o<nS_x  
{ &1l~&,,  
nFileLength = getFileSize(); *t]v}ZV*  
if(nFileLength == -1) jI A#!4  
{ }qL~KA{&  
System.err.println("File Length is not known!"); >;7a1+`3  
} ]q&tQJ/Fa  
else if(nFileLength == -2) ??j&i6sp  
{ k/@Tr
:  
System.err.println("File is not access!"); NZP7r;u  
} =-5[Hn%  
else @i{]4rk lv  
{ KJX>DL 9\  
for(int i=0;i<nStartPos.length;i++) \f<z*!,D$  
{ &Q~)]|t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); UhdqY]  
}
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for(int i=0;i<nEndPos.length-1;i++) .zIgbv s  
{ 6#v
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nEndPos = nStartPos[i+1]; +<{m45  
} ]);NnsG  
nEndPos[nEndPos.length-1] = nFileLength; ^obC4(  
} ; [FLT:$  
} 03Ukw/D&  
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//启动子线程 J)Ol"LXV  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >uHb ^  
for(int i=0;i<nStartPos.length;i++) {!r#f(?uT  
{ _ ~[M+IO   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )(]Envb?A0  
nStartPos,nEndPos,i); `,P >mp)uU  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N8QH*FX/F1  
fileSplitterFetch.start(); TaWaHf  
} -x5F;d}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |Qr:!MA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); TRy^hr8~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Fpf><Rn  
nEndPos = " + nFileLength); G AEZY

 
// fileSplitterFetch[nPos.length-1].start(); 7"a4/e;^  
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*6P
'q4)  
//等待子线程结束 e=L*&X  
//int count = 0; \XDmK  
//是否结束while循环 [8z&-'J=  
boolean breakWhile = false; cJ/4Gl  
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while(!bStop) c=aO5(i0  
{ xl,ryc3J  
write_nPos(); Y;eoTJ  
Utility.sleep(500); Tyd h9I  
breakWhile = true; 6]ZO'Nwo  
|6*Va%LYO-  
{=iyK/Uf  
for(int i=0;i<nStartPos.length;i++) O2lIlCL  
{ }lO }x  
if(!fileSplitterFetch.bDownOver) 4 4`WYK l  
{ |]tZ hI"3<  
breakWhile = false; XWXr0>!,?  
break; I=odMw7Hj  
} 7>&1nBh. f  
} }LQ\a8]<
 
if(breakWhile) $Elkhe]O %  
break; Qt~B#R. V  
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//count++; ( OXY^iq  
//if(count>4)  p[Hr39o  
// siteStop(); Fv@tD4I>  
} U{HML|  
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x?=B\8m  
System.err.println("文件下载结束！"); }AJ L,Q7q  
} =y<0UU  
catch(Exception e){e.printStackTrace ();} Gnv!]c&S>l  
} {$|/|*  
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//获得文件长度
--A&TV  
public long getFileSize() BV1u,<T"  
{ &g {<HU?BT  
int nFileLength = -1; u GAh7Sop  
try{ 2rmNdvvrk  
URL url = new URL(siteInfoBean.getSSiteURL()); C5;wf3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bQj`g2eyM  
httpConnection.setRequestProperty("User-Agent","NetFox"); Bj=@&;  
=]d^3bqN  
5W{hH\E _5  
int responseCode=httpConnection.getResponseCode(); W0|_]"K-  
if(responseCode>=400) ThiN9! Y  
{ xU:4Y0y8  
processErrorCode(responseCode); `0z/BCNB  
return -2; //-2 represent access is error B.RRdK+:  
} y;r"+bS8  
#<]Iz'\`  
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String sHeader; 3C#RjA-2[  
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for(int i=1;;i++) }PmTR4F!}  
{ %ZiK[e3G  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q.1XP  
//Utility.log(in.readLine()); E|{m"RUOy  
sHeader=httpConnection.getHeaderFieldKey(i); ^}@`!ON  
if(sHeader!=null) U3+A MVnB  
{ Bz:&f46{  
if(sHeader.equals("Content-Length")) %",ULtZ+  
{ ]zcV]Qj$~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); C#h76fpH  
break; i pwW%"6  
} qw2)v*Fn  
} XECikld>  
else s6/cL|Ex  
break; 2m_H*1HJ  
} Rf?%Tv
0\  
} /`}6rXnw9  
catch(IOException e){e.printStackTrace ();} mYzcVhV  
catch(Exception e){e.printStackTrace ();} o
6|"J%9GX  
n
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Utility.log(nFileLength); %z2oDAjX  
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return nFileLength; Pj._/$R[/  
} W8VO)3nmD  
KX=/B=3~  
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//保存下载信息（文件指针位置） 80HEAv,O  
private void write_nPos() \6i9q=  
{ jceHKl  
try{ L\YZT| K(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %UBPoq  
output.writeInt(nStartPos.length); O"8P#Ed  
for(int i=0;i<nStartPos.length;i++) wR(ttwxK3  
{ A(NEWO  
// output.writeLong(nPos); wa2~C [  
output.writeLong(fileSplitterFetch.nStartPos); Hva{A #  
output.writeLong(fileSplitterFetch.nEndPos); a}w&dE$!-  
} pJn>oGeJ&  
output.close(); @BXaA0F4  
} Kn.iyR  
catch(IOException e){e.printStackTrace ();} {o {#]fbO%  
catch(Exception e){e.printStackTrace ();}
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} t"tNtLI  
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//读取保存的下载信息（文件指针位置） gkLr]zv  
private void read_nPos() oW8;^u  
{ f@L\E>t  
try{ =@%MV(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =^by0E2  
int nCount = input.readInt(); cmae&Atotw  
nStartPos = new long[nCount]; *%nX#mwz  
nEndPos = new long[nCount]; @Ys
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for(int i=0;i<nStartPos.length;i++) 4 #G3ew  
{ [XxA.S)x3  
nStartPos = input.readLong(); *50ZinfoG  
nEndPos = input.readLong(); 9a-]T=5Ee  
} S`4e@Z$  
input.close(); nE4l0[_  
} N]*!8  
catch(IOException e){e.printStackTrace ();} Re{ej  
catch(Exception e){e.printStackTrace ();} ^,>}%1\  
} (KZUvsSk  
)2/b$i,JKk  
%$^$'6\77  
private void processErrorCode(int nErrorCode) >[hrJn[  
{ g*^wF?t'T  
System.err.println("Error Code : " + nErrorCode); uz8nRS s  
} %bN"bxv^  
ga,
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#i6[4X?  
//停止文件下载 R+C+$?4NG  
public void siteStop() %uF:)  
{ ayHn_  
bStop = true; *SWv*sD  
for(int i=0;i<nStartPos.length;i++) ;>sq_4_  
fileSplitterFetch.splitterStop(); []!tT-Gzy  
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} cS+?s=d  
} v#w4{.8)  
//负责部分文件的抓取  PVS\,  
**FileSplitterFetch.java |I4D(#w.  
*/ v!iWzN  
package NetFox; ^j1Gmv)  
s8C:QC  
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import java.io.*; *pmoLiuB>  
import java.net.*; +W!'B
r  
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public class FileSplitterFetch extends Thread { m21QN9(i%  
TZ)(ZKX*R  
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String sURL; //File URL Z(#XFXd  
long nStartPos; //File Snippet Start Position _ak.G
=  
long nEndPos; //File Snippet End Position X}kVBT1w+x  
int nThreadID; //Thread's ID s#M? tyhj  
boolean bDownOver = false; //Downing is over uHTKo(NG  
boolean bStop = false; //Stop identical `Nc`xO?  
FileAccessI fileAccessI = null; //File Access interface 9*"[pt+tA  
+ ?[ ACZF  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `1}HWLBX.  
{   eYPt  
this.sURL = sURL; /2=_B4E2  
this.nStartPos = nStart; f'8B[&@L  
this.nEndPos = nEnd; Aigcq38  
nThreadID = id; \>&@lA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V7qCbd^>XJ  
} 1v+JCOy  
qQ3]E][/  
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public void run() Djg1Qh  
{ `\4RFr$  
while(nStartPos < nEndPos && !bStop) ;F" kD  
{ }?\#_BCjx(  
sASAsGk<  

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try{ \k2C 5f  
URL url = new URL(sURL); WoC\a^V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1)nM#@%](h  
httpConnection.setRequestProperty("User-Agent","NetFox"); k 2 mkOb  
String sProperty = "bytes="+nStartPos+"-"; '` BjRg57]  
httpConnection.setRequestProperty("RANGE",sProperty); +Y_Q?/M@8  
Utility.log(sProperty); y$+!%y*  
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/1s9;'I  
InputStream input = httpConnection.getInputStream(); 3Y.d&Nz  
//logResponseHead(httpConnection); 3 LZL!^ 5N  
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7  
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byte[] b = new byte[1024]; eWq
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int nRead; BVwRP
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d|D'&&
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{ -;W\f<q]  
nStartPos += fileAccessI.write(b,0,nRead); G~Q*:m  
//if(nThreadID == 1) 8Iqk%n~(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w>1l@%Uo  
} +?J_6Mo@X  
,4h!"c  
8VBkIYgb  
Utility.log("Thread " + nThreadID + " is over!"); js%4;  
bDownOver = true; }kgjLaQ^N  
//nPos = fileAccessI.write (b,0,nRead); %BT)oH}  
} QBN=l\m+  
catch(Exception e){e.printStackTrace ();} 0e7O#-  
}  h;:Se  
} g(z#h$@S  
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,& \&::R  
//打印回应的头信息 ?trt4Tbe/  
public void logResponseHead(HttpURLConnection con) z[$9B#P  
{ -Lz1#Sk]A  
for(int i=1;;i++) Z]1z*dv  
{ A1=$kzw{UH  
String header=con.getHeaderFieldKey(i); [xp~@5r'  
if(header!=null) <*b]JY V@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); iPtm@f,bI  
Utility.log(header+" : "+con.getHeaderField(header)); !<['iM  
else ||"":K  
break; gn4g 43  
} 7oqn;6<[>,  
} ?()E5 4y  
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public void splitterStop() 5G42vTDzS4  
{ aF4V|?+  
bStop = true; [XY:MUe  
} * zJiii  
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} B2Awdw3=g  
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/* 6lH>600]u  
**FileAccess.java @Tm0T7C  
*//文件访问(定位，写) EssUyF-jwU  
package NetFox; -$!Pf$l@  
import java.io.*; 7=M'n;!Mh  
A)`fD %+  
-fZShOBY`  
public class FileAccessI implements Serializable{ Aaw:B?4)  
fU){]YP  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;]`NR  
RandomAccessFile oSavedFile; 3Jk?)Dy  
long nPos; :N'[
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public FileAccessI() throws IOException #.t$A9'  
{ u3?Pp[tM<  
this("",0); Wn9Mr2r!*,  
} !?>p]0*<  
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+ 1%^c(3  
public FileAccessI(String sName,long nPos) throws IOException =jd=Qs IL
 
{ pa> 2JF*  
oSavedFile = new RandomAccessFile(sName,"rw"); 1_E3DXe  
this.nPos = nPos; :92a34  
oSavedFile.seek(nPos); ~4 xBa:*z  
} NB6h/0*v  
#L*@~M^]  
%cjGeS6}  
public synchronized int write(byte[] b,int nStart,int nLen) KL_}:O68  
{ /n3&e  
int n = -1; 0o'ML""j  
try{ Jtk.v49Ad>  
oSavedFile.write(b,nStart,nLen); f`";
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n = nLen; moM&2rgdrQ  
} _/w-gL{  
catch(IOException e) b+#~N>|  
{ @^4M~F%  
e.printStackTrace (); }T*xT>p^3  
} R"kE5:  
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return n; u2x=YUWb]  
} !{ )AV/\D  
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} l$~bk
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+Q#Qu0_   
/* _w,0wn9N$  
**SiteInfoBean.java S/:QVs  
*/ e ~,'|~ C5  
package NetFox;  eJ\j{-  
`j"G=%e3.  
59J$SE  
public class SiteInfoBean { umn~hb5O  
)PATz #  
Kxaz^$5Y$  
private String sSiteURL; //Site's URL -/{}^QWB  
private String sFilePath; //Saved File's Path .t%Vx  
private String sFileName; //Saved File's Name ^{+:w:g  
private int nSplitter; //Count of Splited Downloading File >u#VHaB  
r%mTOLef  
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public SiteInfoBean() tNf" X!  
{//nSplitter的缺省值为5 A =#-u&l  
//default value of nSplitter is 5 ?{P6AF-xcf  
this("","","",5); iBW6<2@oZF  
} RvZ-w$E&?  
T[=cKYp8\  
Qi]Z)v{^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cTx/Y&\9  
{ +rO<'H:umJ  
sSiteURL= sURL; 4'[ V'c\  
sFilePath = sPath; 29DWRJU  
sFileName = sName; l5nDt$Ex  
this.nSplitter = nSpiltter; 05LQh  
[)0k}  
+7OT`e %q  
} exKmK!FT  
4'b]2Mn3   
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public String getSSiteURL() (SVr>|Db  
{ 9+Hb`  
return sSiteURL; fzG1<Gem  
} 8J U~Q  
?t P/VL  
''07Km@x  
public void setSSiteURL(String value) -{SiK  
{ vs5wxTM  
sSiteURL = value; L umD.3<  
} ?Gw89r  
<&Xq`i/(  
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public String getSFilePath() PzkXrDlB7  
{ fsuvg jlE  
return sFilePath; yyDBW`V((  
} -s "$I:v  
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C P v}A  
public void setSFilePath(String value) o@;_(knb  
{ Y &+/[[  
sFilePath = value; *lO+^\HXD  
} TBT*j&!L  
WfO$q^'?DP  
CxQ,yd;>  
public String getSFileName() Khd,|pM  
{ 6\@, Lb  
return sFileName; RyD$4jk+T"  
} H2cc).8"  
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2MeavTr  
public void setSFileName(String value) dq(L1y870  
{ e1Hx"7ew_  
sFileName = value;
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} 3vD,hL`&  
W RaO.3Q@.  
]zY'w,?D\F  
public int getNSplitter() 1]`HX=cl  
{ ]~ UkD*Ct  
return nSplitter; _S1uJ~j;E  
} VNXVuM )c  
nP31jm+A  
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public void setNSplitter(int nCount) 5C?1`-&65V  
{ :h~!#;w_  
nSplitter = nCount; <2d@\"AoHE  
} Ij_`=w<  
} f'U]Ik;Jy  
E1_4\S*z  
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/* #Qd3
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**Utility.java :nEV/"#F  
*/ .x%SbG<k{  
package NetFox; 
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_"V0vV  
public class Utility { lsi8?91  
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public Utility() UC@"<$'C  
{ 8ipLq`)  
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} D IN PAyY  
+Z*%,m=N(  
//线程睡眠 I),8EEf\  
public static void sleep(int nSecond) _: K\v8  
{ }Jfo(j  
try{ ?#m5$CFp  
Thread.sleep(nSecond); vxx3^;4p  
} YSif`W!  
catch(Exception e) Qrh9JFqdG6  
{ |?kH]Trr  
e.printStackTrace (); r~!lD9R~  
} 9n'p7(s%  
} {9MYEN}FO  
1-#tx*>AY  
//日志 Jhc
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public static void log(String sMsg) GZo4uwG@a  
{ <~OyV5:6  
System.err.println(sMsg); ND>}t#^$  
} _#:1Axx1  
0*^Fk=>ej  
(tvh9o  
public static void log(int sMsg) ,+&j/0U  
{ rpmDr7G  
System.err.println(sMsg); DVl:s  
} x3 S
 
}  Eqc$*=  
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G
w[&P%  
/* U9w*x/Swb  
**TestMethod.java KX`,7-  
*/ e j9G[  
package NetFox; |.A>0-']M  
?H&p zY~H  
4SYN$?.Mp  
public class TestMethod { b}:Z(L,\  
|=POV]K  
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public TestMethod() o[6hUX0tN  
{ ///xx/weblogic60b2_win.exe l;uEw  
try{ d9(FwmE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @w0[5ZAj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (EX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); U VT8TN-T  
fileFetch.start(); ! bp"pa9  
}
~CA+'e%~~  
catch(Exception e){e.printStackTrace ();} gi)/iz`  
)zN )7  
$gNCS:VG*  
} J*k4&l  
sAN#j {  
[H1NP'Kg]  
public static void main(String[] args) FyEl@ }W  
{ C6n
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new TestMethod(); SxDE
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} ;Yj}9[p;T  
} TI332,eL  
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