http断点续传简单实现（java)

/* t3}_mJ  
**SiteFileFetch.java ~ cu+QR)  
*/ bZK`]L[   
package NetFox; .ozBa778u
 
import java.io.*; N0D5N(kH%  
import java.net.*; #0*I|gfV  
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public class SiteFileFetch extends Thread { T|oDJ]\J  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 23;\l   
long[] nStartPos; //开始位置 } -hH2  
long[] nEndPos; //结束位置 U!"RfRD.<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;SA+
|,  
long nFileLength; //文件长度 _mQ~[}y+?  
boolean bFirst = true; //是否第一次取文件 bX`]<$dr3  
boolean bStop = false; //停止标志 Y\1& Uk  
File tmpFile; //文件下载的临时信息 =5pwNi_S  
DataOutputStream output; //输出到文件的输出流 2j>C4Ck  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n n8N 9w  
public SiteFileFetch(SiteInfoBean bean) throws IOException sh<JB`^$(?  
{ g2r8J0v  
siteInfoBean = bean; 7V\M)r{q7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b$Bq#vdg:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l_q1h]/   
if(tmpFile.exists ()) %s%e5hU  
{ -cXVkH{  
bFirst = false; 7x |Pgu(  
read_nPos(); "Jyb?5  
} ?0E-Lac=  
else b{e|~v6&  
{ 8=sMmpB 7u  
nStartPos = new long[bean.getNSplitter()]; qp1rP#  
nEndPos = new long[bean.getNSplitter()]; w$I$xup  
} Zf\It<zT5  
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} f=MR.\  
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public void run() Zf`ddT  
{ +Mh9Jf  
//获得文件长度 }JWk?  
//分割文件 2!bE|  
//实例FileSplitterFetch laFF/g;sRC  
//启动FileSplitterFetch线程 6sRKbp|r7  
//等待子线程返回 3WdANR  
try{ le`_  
if(bFirst) i_;]UvP  
{ EabZ7zFoN  
nFileLength = getFileSize(); .hXdXY  
if(nFileLength == -1) bPdbKi{j@  
{ m&#a M8:\  
System.err.println("File Length is not known!"); [R[Suf  
} d~J4&w  
else if(nFileLength == -2) vo DTU]pf  
{ q^w3n2
 
System.err.println("File is not access!"); >;@hA*<  
} 
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else r5?qz<WW~  
{ (Sg52zv  
for(int i=0;i<nStartPos.length;i++) "&/&v  
{ !Q5ip'
L  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jlZW!$Iq  
} V qW(S1w  
for(int i=0;i<nEndPos.length-1;i++) k/#& ]8(  
{ AiO29<  
nEndPos = nStartPos[i+1]; vb.`rj6  
} !>+Na~eN  
nEndPos[nEndPos.length-1] = nFileLength; ~?{"H<  
} Ci ? +Sl  
} 7MT[fA8^  
UI 7JMeV  
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//启动子线程 /\KB*dX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0 .dSP$e  
for(int i=0;i<nStartPos.length;i++) 8W"~>7/>D  
{ xCV3HnZ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G =+sW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *5#Y[c  
nStartPos,nEndPos,i); "+ji`{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,wlh0;,  
fileSplitterFetch.start(); @3K 4,s  
} M+ gYKPP  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bd2"k;H<o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); BS#@ehdig  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ee##:I[z  
nEndPos = " + nFileLength); h2Z Gh  
// fileSplitterFetch[nPos.length-1].start(); kN>AY'1  
;%#@vXH[Oo  
#IP<4"Hf  
//等待子线程结束 w7"Z@$fs  
//int count = 0; @fbB3  
//是否结束while循环 l 49)Cv/  
boolean breakWhile = false; Px}#{fkS  
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while(!bStop) UGPD5wX?  
{ |YQ:4'^"  
write_nPos(); v>$GVCY  
Utility.sleep(500); ~OEP)c\k  
breakWhile = true; h?DMrYk_%#  
l\*}  
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for(int i=0;i<nStartPos.length;i++) xUzSS@ot^  
{ 5HioxHL  
if(!fileSplitterFetch.bDownOver) ;EE*#"IJ  
{ A[ZJS  
breakWhile = false; >=i47-H  
break; h.g11xa  
} 'UT 4x9&z  
} OlFls 8#>  
if(breakWhile) pP)0 l  
break; ^owEB%  
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abCcZ<=|b  
//count++; >)U 7$<&b  
//if(count>4) {`~{%2ayq7  
// siteStop(); *
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} Lqbu]  
4fZ$&)0&  
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System.err.println("文件下载结束！");
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} yGH'|`  
catch(Exception e){e.printStackTrace ();} sN7I~  
} gV!Eotq  
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//获得文件长度 >RBq&'f  
public long getFileSize() Z.:5<oEKg  
{ Lz=nJn  
int nFileLength = -1; Y+V*$73`  
try{ q[1H=+  
URL url = new URL(siteInfoBean.getSSiteURL()); @C7S^|eo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x-U:T.+{  
httpConnection.setRequestProperty("User-Agent","NetFox"); )~O{jd  
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int responseCode=httpConnection.getResponseCode(); 6k42>e*p  
if(responseCode>=400) [t<^WmgtxL  
{ g 6>RyjN  
processErrorCode(responseCode); ?qw&H /R  
return -2; //-2 represent access is error q!""pr<n  
} <hdR:k@#  
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String sHeader; <jw`"L[D
 
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for(int i=1;;i++) k^]+I%?Q  
{ E[nWB"pxE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); fbwo2qe@K  
//Utility.log(in.readLine()); \?GUGs  
sHeader=httpConnection.getHeaderFieldKey(i); 68Wm=j.m  
if(sHeader!=null) b\][ x6zJp  
{ Z=R>7~H  
if(sHeader.equals("Content-Length")) /Rx%}~x/m  
{ /I$g.f/#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QCa$<~c  
break; ?_m;~>C  
} =:6Y<ftC  
} N~\1yQT  
else ;TM
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break; z:RwCd1\  
} u+[ZWhKUp  
} bW3e*O$V  
catch(IOException e){e.printStackTrace ();} :5U(}\dL{  
catch(Exception e){e.printStackTrace ();} o*f7/ZP1o  
@ L%3}  
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Utility.log(nFileLength); g?^o++  
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return nFileLength; <z%zzc1s  
} hP`3Ao  
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//保存下载信息（文件指针位置） JT[|l-\zo  
private void write_nPos()  Cj_cu  
{ Rw^4S@~T  
try{ 2P!Pbl<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Xy_+L_h^  
output.writeInt(nStartPos.length); >Ah [uM  
for(int i=0;i<nStartPos.length;i++) 9N5&N3  
{ r$=iM:kERC  
// output.writeLong(nPos); QI=",vmau  
output.writeLong(fileSplitterFetch.nStartPos); 4@/
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output.writeLong(fileSplitterFetch.nEndPos); 2o6KVQ  
} P3on4c  
output.close(); FGzB7w#  
} dL |D  
catch(IOException e){e.printStackTrace ();} T.`EDluG  
catch(Exception e){e.printStackTrace ();} Cbx/  
} +sQ=Uw#e  
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//读取保存的下载信息（文件指针位置） zp!{u{  
private void read_nPos() XcR2]\  
{ XBF#ILJ  
try{ b5No>U) /  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %gkRG66  
int nCount = input.readInt(); Wf-i)oc4I  
nStartPos = new long[nCount]; ] RN&s  
nEndPos = new long[nCount]; Cc$!TZq=  
for(int i=0;i<nStartPos.length;i++) i"0^Gr  
{ ,=Xr'7w,  
nStartPos = input.readLong(); PUuxKW}  
nEndPos = input.readLong(); q$(aMO&J  
} 4~P{H/]  
input.close(); (5cc{zKtR  
} -,uTAk0+@  
catch(IOException e){e.printStackTrace ();} Y]Vt&*{JV  
catch(Exception e){e.printStackTrace ();} [v^T]L  
} =;l.<{<VH  
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private void processErrorCode(int nErrorCode) p3&/F=T;)  
{ "n^h'// mn  
System.err.println("Error Code : " + nErrorCode); I+rHb< P%  
} FDbb/6ku  
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//停止文件下载 )^qM%k8  
public void siteStop() zq>pK_WG  
{ s )POtJ<  
bStop = true; ({v$!AAv  
for(int i=0;i<nStartPos.length;i++) E/v.+m  
fileSplitterFetch.splitterStop(); , ;W6wj  
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} ",!#7h  
} qjFz}6  
//负责部分文件的抓取 |]1-ck!  
**FileSplitterFetch.java !8lG"l|,l  
*/ .vE=527g)  
package NetFox; i ?&t@"'  
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import java.io.*; 2BZYC5jy  
import java.net.*; }TY}sr  
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%X7R_>.   
public class FileSplitterFetch extends Thread { >Akrbmh5  
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String sURL; //File URL f4UnLig  
long nStartPos; //File Snippet Start Position [EI~/#;  
long nEndPos; //File Snippet End Position _1Iy/T@1  
int nThreadID; //Thread's ID a\;1%2a  
boolean bDownOver = false; //Downing is over }(k#,&Fv`  
boolean bStop = false; //Stop identical v%v(-, _q  
FileAccessI fileAccessI = null; //File Access interface @32~#0a  
a~q_2S]h  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException O<7Q>m  
{ cq lA"Eof  
this.sURL = sURL; 4wYD-MB  
this.nStartPos = nStart; Le;;
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this.nEndPos = nEnd; 701a%Jq_2  
nThreadID = id; Z/-9G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Geyy!sr``  
} qTSyy=  
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public void run() sZe$?k|  
{ KaVNRS  
while(nStartPos < nEndPos && !bStop) s?Lx\?T  
{ s
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try{ LLyw9y1  
URL url = new URL(sURL); -55[3=#

 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yP$@~L[!  
httpConnection.setRequestProperty("User-Agent","NetFox"); [|iWLPO1&k  
String sProperty = "bytes="+nStartPos+"-"; }9:(l  
httpConnection.setRequestProperty("RANGE",sProperty); D5Zgi!  
Utility.log(sProperty); jr/  
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&10l80vj  
InputStream input = httpConnection.getInputStream(); L`'#}#O l  
//logResponseHead(httpConnection); k+9*7y8w  
*Bfo"["0.  
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byte[] b = new byte[1024]; m(>MP/  
int nRead; Ibf~gr(j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NS<C"O  
{ Vz.G!*>Dg  
nStartPos += fileAccessI.write(b,0,nRead); Zv]'9,cbk  
//if(nThreadID == 1)
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LTZ8Eu  
} 8F>u6Y[P  
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Utility.log("Thread " + nThreadID + " is over!"); WCNycH+1  
bDownOver = true; G]]"Jc  
//nPos = fileAccessI.write (b,0,nRead); Yg/g9$'  
} _0cCTQE  
catch(Exception e){e.printStackTrace ();} 7xF)\um  
} r'
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} 1d$qr`  
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//打印回应的头信息 W [
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public void logResponseHead(HttpURLConnection con) c,2OICj  
{ OV G|WC  
for(int i=1;;i++) 4s s 4O  
{ a}e GB +  
String header=con.getHeaderFieldKey(i); z@g%9|U  
if(header!=null) ')
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); F9} zt 9  
Utility.log(header+" : "+con.getHeaderField(header)); >D jJ*vM  
else z!M #  
break; #a`D6;  
} nTtE+~u  
} ~6"=d  
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;AG&QdTMh  
public void splitterStop() !/a![Ne  
{ 7lx" X0w*m  
bStop = true; yV~TfTJ  
}
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} PNo9.-@G  
?8do4gT+1  
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/* =@nE:uto]  
**FileAccess.java J-|&[-Z  
*//文件访问(定位，写) ih|;H:"^  
package NetFox; 7KHQ0  
import java.io.*; ?KB] /gT^  
m-qu<4A/U|  
]K3bDU~  
public class FileAccessI implements Serializable{ YQ@2p?4m  
nQOzKw<j%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 W}y)vrL  
RandomAccessFile oSavedFile; ,(RpBTV  
long nPos; a/v]E]=qI  
F( 4Ue6R  
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public FileAccessI() throws IOException S&'?L0  
{ ]%ewxF  
this("",0); FWB *=.A9  
} K^6d_b&  
o[1#)&  
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public FileAccessI(String sName,long nPos) throws IOException }$'XV.  
{ QI'-I\Co  
oSavedFile = new RandomAccessFile(sName,"rw"); _R(
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this.nPos = nPos; aZ|?i }  
oSavedFile.seek(nPos); E]v]fy"  
} ubZJUm  
c
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Y]_$+Si:NK  
public synchronized int write(byte[] b,int nStart,int nLen) }VRl L>HAC  
{ +?
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int n = -1; : h(Z\D_  
try{ n!.=05OtX  
oSavedFile.write(b,nStart,nLen); {n&n^`Em  
n = nLen; (/0dtJ  
} xFekSH7[F  
catch(IOException e) QFnpp\K  
{ &S`g&  
e.printStackTrace (); MD*dq  
} J2 /19'QE  
eM 5#L,Y{  
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return n; L,.AY?)+7  
} ByuBZ!m  
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} H] g=( %ok  
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[=BMvP5  
/* dA (n,@{  
**SiteInfoBean.java )[cuYH>  
*/ $qr6LIKGw  
package NetFox; =-_hq'il  
a|=^   
u]7wd3(  
public class SiteInfoBean { _yUYEq<`  
:s&dn%5N"  
|IV7g*J89  
private String sSiteURL; //Site's URL W8$0y2  
private String sFilePath; //Saved File's Path }#u #m.  
private String sFileName; //Saved File's Name ,~&HL7v  
private int nSplitter; //Count of Splited Downloading File "&/2@

 
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:fwtPvLo  
public SiteInfoBean() :\qapFV  
{//nSplitter的缺省值为5 4p-"1c$  
//default value of nSplitter is 5 :b(W&iBWhI  
this("","","",5); JKfJ%yy |  
} $H[q5(_~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )gSqO{Z  
{ 0+$gR~^^  
sSiteURL= sURL; &Jb\}c}  
sFilePath = sPath; G`kz 0Vk  
sFileName = sName; #=S^i[K/  
this.nSplitter = nSpiltter; TEY~E*=}$  
i>,AnkI&  
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} Jy%?"wn  
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public String getSSiteURL() A]'jsv!+  
{ Q8AAu&te7  
return sSiteURL; !rr,(!Ip?O  
} M*ZN]9{^.  
Ikf[K%NKn  
|u^S}"@3sU  
public void setSSiteURL(String value) 7+hF1eoI  
{ ,0,Fzx
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sSiteURL = value; ;*<R~HJt  
} B+U:=591  
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?.%dQ0  
public String getSFilePath() M1xsGa9h&  
{ oo2d,  
return sFilePath; 6Q

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} nL/]
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p? o[+L<  
public void setSFilePath(String value) UAhWJ$(C  
{ {~F|"v  
sFilePath = value; 'WE"$1  
} [UI>SN  
]&]DFY~n  
8I
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public String getSFileName() i$<['DY  
{ Dk^AnMx%_  
return sFileName; s$hO/INr  
} jBYvOy*$Q  
b;UDgq8v  
oH%[8!#  
public void setSFileName(String value) N=<`|I  
{ Uc {m##!  
sFileName = value; "nu]3zcd  
} zT78FliY6  
VZWo.Br'W  
[5?Dov^j3  
public int getNSplitter() mW%8`$rVEO  
{ `_OrBu[  
return nSplitter; s%K(hk  
} F5 ]<=i  
)&j`5sSXcr  
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public void setNSplitter(int nCount) ~h3G}EH  
{ p lnH  
nSplitter = nCount; rV%T+!n%c  
} b`#YJpA  
} JpfA+r  
1 6zxPSTr}  
+zMPkbP6  
/* /#Aw7F$Ey  
**Utility.java CXuD%H]tx  
*/ 0AQ4:K
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package NetFox; `;6M|5G  
fI)XV7,X  
CwX?%$S   
public class Utility { j;-Wf6h{  
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public Utility() y 9]d{:9  
{ h(/? 81:  
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} '\#q7YjaL  
ML12&E>  
//线程睡眠 %[p*6&V  
public static void sleep(int nSecond) {:gx*4}q8  
{ Zmyq6.1q~  
try{ a20w.6F  
Thread.sleep(nSecond); b\(f
>
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} {S=<(A@  
catch(Exception e) vMp=\U-~^  
{ gGVt( ^  
e.printStackTrace (); l7VO8p]y[R  
} 2X2Ax~d@  
} s1 >8uW  
< c^'$  
//日志 FFw(`[A_  
public static void log(String sMsg) e#;43=/Ia  
{ #'&-S@/nQs  
System.err.println(sMsg); ?_g
vI  
} %>*?uO`z[  
swj\X,{  
Y5GN7.  
public static void log(int sMsg) 5_!L"sJ  
{ 0cHcBxdF  
System.err.println(sMsg); ~RbVcB#  
} U%@
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} vX }iA|`#  
,5c7jZ5H  
}SSg>.48w  
/* Wm
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**TestMethod.java rB+ (  
*/ 66?`7j X  
package NetFox; ^N<aHFF  
K7&]|^M9  
U=D;CjAh  
public class TestMethod { l5w^rj  
YeOn   
]#M"|iTR  
public TestMethod() F4\:9ws  
{ ///xx/weblogic60b2_win.exe 1^$hbRq  
try{ -"xAeI1+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X{#^O/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ph6/+[:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :/(G#ZaV  
fileFetch.start(); zKP[]S-  
} &pI\VIx ?  
catch(Exception e){e.printStackTrace ();} b$Hbo;_  
*m"@*O'  
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} auN
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ek)rsxf1A  
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public static void main(String[] args) i-0 :Fs  
{ 2f:hz  
new TestMethod(); 4mY^pQ1=L  
} G--vwvL  
} ?T73BL=  
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