http断点续传简单实现（java)

/* }PXWRv.gW  
**SiteFileFetch.java +bSv-i-  
*/ n33SWE(  
package NetFox; {ys_uS{c*  
import java.io.*; kO.rgW82  
import java.net.*; E,rPM  
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public class SiteFileFetch extends Thread { 'e&4#VLH^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean l]ZUKy  
long[] nStartPos; //开始位置 }YjSv^  
long[] nEndPos; //结束位置 d/^^8XUK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 VTHDGBU  
long nFileLength; //文件长度 j7W_%Yk|E  
boolean bFirst = true; //是否第一次取文件 l>G#+#{  
boolean bStop = false; //停止标志 t.w?OyO  
File tmpFile; //文件下载的临时信息 9\xw}ph  
DataOutputStream output; //输出到文件的输出流 O$$N{  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jIl-}/2  
public SiteFileFetch(SiteInfoBean bean) throws IOException (=X16}n:>  
{ saZ;ixV  
siteInfoBean = bean; Y7p#K<y]9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0I k@d'7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); s?2;u p*D  
if(tmpFile.exists ()) KyDBCCOv  
{ xs:{%ki  
bFirst = false; R0|X;3  
read_nPos(); u Qj#U m8  
}
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else |amEuKJ  
{ R|vF*0)>W  
nStartPos = new long[bean.getNSplitter()]; H(X~=r  
nEndPos = new long[bean.getNSplitter()]; Vs"Z9p$U  
} T>z@;5C  
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} wHCsEp(  
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public void run() u+V;r)J{  
{ c:iMbJOn#  
//获得文件长度 v6rw.  
//分割文件 nO/5X>A,Zw  
//实例FileSplitterFetch <@yyx7  
//启动FileSplitterFetch线程 vxgm0ZOMN  
//等待子线程返回 ~\^8 ^  
try{ rB)WHx<  
if(bFirst) uZ^i8;i  
{ L`!sV-.  
nFileLength = getFileSize(); nMnc&8r  
if(nFileLength == -1) 9xz`
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{ D^u{zZy@e  
System.err.println("File Length is not known!"); FlZ]R  
} {kzM*!g  
else if(nFileLength == -2) V^ :\/EU  
{ DXiD>1(q  
System.err.println("File is not access!"); zf!c  
} WX[ycm8  
else zEGwQp<  
{ gV7o eZ5  
for(int i=0;i<nStartPos.length;i++) q8D1MEBL`  
{ [brrziZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @!S$gTz  
} qvscf_%FM  
for(int i=0;i<nEndPos.length-1;i++) :K~7BJ(HO  
{ WZMsmhU@T  
nEndPos = nStartPos[i+1]; iO@wqbg$6  
} ?BRL;(x  
nEndPos[nEndPos.length-1] = nFileLength; u>eu47"n!  
} ?R+$4;iy  
} Jq!($PdA  
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//启动子线程 UvI!e4_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p
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for(int i=0;i<nStartPos.length;i++) ^>"?!lv  
{ :b=0_<G
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bcZonS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IIPf5 Z}A  
nStartPos,nEndPos,i); pxF!<nN1,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -K!-a'J  
fileSplitterFetch.start(); vuAjAeKm  
} /?GBp[(0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G pd:k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;CW$/^QNr5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XVfQscZe  
nEndPos = " + nFileLength); d?K8Ygz  
// fileSplitterFetch[nPos.length-1].start(); dO@iq^9-  
9~_6mR<  
Gl:ASPZ6  
//等待子线程结束 x:xQXjJ  
//int count = 0; {)y4Qp  
//是否结束while循环 _H,RcpyJ  
boolean breakWhile = false; )t4C*+9<U  
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while(!bStop) ]'G7(Y\)f  
{ d !H)voX  
write_nPos(); :NLNxK  
Utility.sleep(500); *O;N"jf  
breakWhile = true; Nm~#$orI|  
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for(int i=0;i<nStartPos.length;i++) _=]
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{ cMg/T.O  
if(!fileSplitterFetch.bDownOver) q mB@kbt  
{ :wZZ 1qa  
breakWhile = false; .EcMn  
break; |2# Ro*  
} u;!Rv E8N  
} `+uXL9
mo  
if(breakWhile) ~
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break; $enh45Wy  
;w>B}v;RE  
<wC1+/]  
//count++; yiOF&  
//if(count>4) .phQ7":`  
// siteStop(); ^wlep1D  
} <'-me09C*  
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System.err.println("文件下载结束！"); J\V(MN,  
} [OcD#~drO  
catch(Exception e){e.printStackTrace ();} riL!]'akV  
} ,zFN3NLtA  
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//获得文件长度 >U)O@W)  
public long getFileSize() J[
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{ N;HvB:c  
int nFileLength = -1; Ce:ds%  
try{ <Va>5R_
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URL url = new URL(siteInfoBean.getSSiteURL()); ( ~>Q2DS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T!PX?  
httpConnection.setRequestProperty("User-Agent","NetFox"); msylb~^  
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int responseCode=httpConnection.getResponseCode(); m5Kx}H~  
if(responseCode>=400) Mx"tUoU6z  
{ MF`'r#@:wa  
processErrorCode(responseCode); i1 &'Zh  
return -2; //-2 represent access is error N,|oV|i  
} U4gwxK  
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String sHeader; ]_?y[@ZP  
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for(int i=1;;i++) bed+Ur&  
{ ;Y\,2b, xh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); P{18crC[1  
//Utility.log(in.readLine()); /5Loj&!=  
sHeader=httpConnection.getHeaderFieldKey(i); R`q!~8u  
if(sHeader!=null) Oe`t!&v  
{ \`ReZu$  
if(sHeader.equals("Content-Length")) ^%pwyY\t  
{ sLIP|i  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4)I#[&f  
break; v=VmiB
q[  
} b`zf&Mn  
} }c%y0)fL
 
else ?miM15XI  
break; ?M^t4nj  
} "Ycd$`{Vgt  
} 3G^Ed)JvE  
catch(IOException e){e.printStackTrace ();} *.g?y6d  
catch(Exception e){e.printStackTrace ();} EB<q.  
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Utility.log(nFileLength); CN(4;-so)  
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HU
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return nFileLength; (_ah~VnO  
} avu,o  
;!?K.,N:N  
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//保存下载信息（文件指针位置） ;4$C$r!t  
private void write_nPos() }8 _9V|E  
{ 0(x@ NGb>{  
try{ -^v}T/Kl#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (p=GR#  
output.writeInt(nStartPos.length); R"`{E,yj  
for(int i=0;i<nStartPos.length;i++) :'~ gLW>j  
{ "b4iOp&:=  
// output.writeLong(nPos); ZnLk :6'  
output.writeLong(fileSplitterFetch.nStartPos); tL{~O=  
output.writeLong(fileSplitterFetch.nEndPos); 0z7mre^Q  
} 7"ps#)O  
output.close(); ]xEE7H]\h  
} MXk. 2  
catch(IOException e){e.printStackTrace ();} W+e*(W|d6  
catch(Exception e){e.printStackTrace ();} TZNgtR{q  
} N'P,QiR,z<  
.+}o'rU  
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//读取保存的下载信息（文件指针位置） 389.&`Q%Ut  
private void read_nPos() a] =\h'S  
{ 9t.yP;j\Y  
try{ jSp&mD*xv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _x6E_i-(  
int nCount = input.readInt(); 3Lki7QW`  
nStartPos = new long[nCount]; ID#qKFFW  
nEndPos = new long[nCount]; &xroms"S=  
for(int i=0;i<nStartPos.length;i++) e-3pg?M  
{ O&iYGREO  
nStartPos = input.readLong(); GD{fXhgk  
nEndPos = input.readLong(); kDY]>v  
} `yX+NRi(s  
input.close(); eZ5}O0sfp  
} T,2Dr;  
catch(IOException e){e.printStackTrace ();} 2%C5P0;QX  
catch(Exception e){e.printStackTrace ();} DN':-PK  
} OKP_3Ns  
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private void processErrorCode(int nErrorCode) nvo1+W(%  
{ Ja=70ZI^6  
System.err.println("Error Code : " + nErrorCode); umZ g}|C_  
} 9^#gVTGXv  
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K6*UFO4}i  
//停止文件下载 vq:OH H  
public void siteStop() i2a"J&,6O  
{ L_1_y, 0N  
bStop = true; 1 lCikS^c  
for(int i=0;i<nStartPos.length;i++) Jo aDX ,  
fileSplitterFetch.splitterStop(); \*!%YTZ~  
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} ZHD0u)ri=J  
}  Am%a4{b  
//负责部分文件的抓取 U"y'Kd  
**FileSplitterFetch.java _7.GzQJ  
*/ |;u%JW$4  
package NetFox; DT"Zq  
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import java.io.*; k-cIb@+"  
import java.net.*; f@Rpb}zg+C  
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public class FileSplitterFetch extends Thread { Y:!/4GF  
xCp+<|1  
?~JxO/K  
String sURL; //File URL pY!dG-;  
long nStartPos; //File Snippet Start Position |8qK%n f}  
long nEndPos; //File Snippet End Position u~- fK'/!|  
int nThreadID; //Thread's ID QB3d7e)8>  
boolean bDownOver = false; //Downing is over }d3N`TT  
boolean bStop = false; //Stop identical {_toh/8)r  
FileAccessI fileAccessI = null; //File Access interface #w,WwL!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |;U=YRi  
{ N[x@j)w-`  
this.sURL = sURL; YUVc9PV)Ws  
this.nStartPos = nStart; 56=K@$L {F  
this.nEndPos = nEnd; RnA&-\|*  
nThreadID = id; SeNF!k% Y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7hN6IP*so  
} K[LVT]3 n  
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y }&4HrT&  
public void run() <% 7P  
{ }y-;>i#m=g  
while(nStartPos < nEndPos && !bStop) ^0x.'G?  
{ bg1"v a#2  
Ld}(*-1i  
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try{ N?=qEX|R  
URL url = new URL(sURL); ?dKa;0\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2 ]DCF  
httpConnection.setRequestProperty("User-Agent","NetFox"); eN|HJ=  
String sProperty = "bytes="+nStartPos+"-"; `b.o&t$L  
httpConnection.setRequestProperty("RANGE",sProperty); qaMZfA  
Utility.log(sProperty); 2c"N-c&A  
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InputStream input = httpConnection.getInputStream(); TvWU[=4Yk  
//logResponseHead(httpConnection); Ku0H?qft(  
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byte[] b = new byte[1024]; *qO]v9 j  
int nRead; i{|lsd(+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) BbXU|QtY  
{ dI_r:xN  
nStartPos += fileAccessI.write(b,0,nRead); Iu-'o  
//if(nThreadID == 1) ;h,R?mU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;-9zMbte:  
} u 5Eo  
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Utility.log("Thread " + nThreadID + " is over!"); ovQS ET18b  
bDownOver = true; LZUA+x(  
//nPos = fileAccessI.write (b,0,nRead); d DIQ+/mmg  
} ^.@yF;H  
catch(Exception e){e.printStackTrace ();} |C$:]MZx  
} 4V228>9w  
} =GH@.3`X  
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//打印回应的头信息 "GwWu-GS  
public void logResponseHead(HttpURLConnection con) b(|%Gbg@c  
{ 7wiK.99  
for(int i=1;;i++) =`]|/<=9'U  
{ pYLY;qkG"  
String header=con.getHeaderFieldKey(i); Mt[Bq6}ZD  
if(header!=null) P1 7>6)a  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;Na8_}  
Utility.log(header+" : "+con.getHeaderField(header)); k1f3?l vlU  
else S_T{L  
break; &Rt+LN0qB0  
} FE8+E\ U?  
} QmH/yy3.%  
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public void splitterStop() zdLVxL>87  
{ I;kf #nvao  
bStop = true; ub`z7gL  
} .8T\Nr\~2  
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} CF3E]dt  
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/*  /,1SE(  
**FileAccess.java LKR==;qn  
*//文件访问(定位，写) "xD}6(NL(r  
package NetFox; DL'd&;6  
import java.io.*; TnN^2:cU  
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public class FileAccessI implements Serializable{ pG,<_N@P  
",~ b2]ym  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]PR|d\O  
RandomAccessFile oSavedFile; o5N]((9  
long nPos; 0M#N=%31  
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public FileAccessI() throws IOException eZ!yPdgy|  
{ f![xn2T  
this("",0); y!7B,  
} ?-pxte8  
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public FileAccessI(String sName,long nPos) throws IOException -!XrwQyk  
{ gf:vb*#Wa  
oSavedFile = new RandomAccessFile(sName,"rw"); u{g]gA8s  
this.nPos = nPos; ,3VG.u;U   
oSavedFile.seek(nPos); KH>Sc3p  
} `xISkW4%  
2-8YSHlh  

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public synchronized int write(byte[] b,int nStart,int nLen) beJZpg  
{ nnfY$&3A  
int n = -1; q$MHCq;  
try{ |9+bSH9  
oSavedFile.write(b,nStart,nLen); _n< LVdE  
n = nLen; >lA7*nn  
} ?D1x;i9<  
catch(IOException e) jv*Dg (  
{
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e.printStackTrace (); CHPL>'NJzc  
} SW3wMPy&s  
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return n; Ezi' 2S
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} P-[fHCg~  
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} G{F6  
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/* `if
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**SiteInfoBean.java :_MP'0QP  
*/ |)^clkuGX  
package NetFox; :L]-'\y  
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|$M@09,F"  
public class SiteInfoBean { UE"7

  
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private String sSiteURL; //Site's URL H9sZR>(^  
private String sFilePath; //Saved File's Path $b4*/vMr  
private String sFileName; //Saved File's Name cE^kpnVq|<  
private int nSplitter; //Count of Splited Downloading File :[L{KFQU  
cL?\^K)  
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public SiteInfoBean() U%Dit  
{//nSplitter的缺省值为5 {*sGhGwr  
//default value of nSplitter is 5 0xN!DvCg>.  
this("","","",5); (2: N;  
} lrCm9Oy  
+:}kZDl@ X  
:]EP@.(  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =\M)6"}y}  
{ }bZ 8-v  
sSiteURL= sURL; @o`sf-8x  
sFilePath = sPath; +IvNyj|  
sFileName = sName; "Lb fF  
this.nSplitter = nSpiltter; uH$oGY  
]GcV0&|  
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} NK8<= n%"  
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public String getSSiteURL() 2>g^4(  
{ 7@JjjV  
return sSiteURL; vxb@9eb!H  
} B i'd5B5  
: -E,  
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public void setSSiteURL(String value) u',b1 3g(  
{ 5;}2[3}[  
sSiteURL = value; `4_c0q)N4  
} Jl\'V
  
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public String getSFilePath() 2bkJ /u`i  
{ -=5EbNPwG  
return sFilePath; TM)u?t+[  
} X2LV&oi  
su}&".e^  
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public void setSFilePath(String value) 00"CC  
{ V- /YNRV  
sFilePath = value; kY=rz&?U  
} 7q!?1 -?8R  
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0Yp>+:#  
public String getSFileName() KyjyjfIwH  
{ a%v>eXc  
return sFileName; >[EBpYi  
} >G&^?5  
;ed#+$Na  
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public void setSFileName(String value) r|<6Aae&  
{ =)(0.E  
sFileName = value; Nfg{,/O  
} c+~LpSQ  
=x1Wii$`  
#,TELzUVE  
public int getNSplitter() lirNYJ]tO  
{ Yc|uD-y  
return nSplitter; 1&|  
} P8<hvMF  
mzz$`M1  
f9a$$nb3`  
public void setNSplitter(int nCount) RtwUb(wn6  
{
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nSplitter = nCount; )(lJT&e  
} <1K7@Tu  
} 3-iD.IAUm@  
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/* ,m:L2 -J@  
**Utility.java (vnoP< 0  
*/ Cs#w72N  
package NetFox; JYQ.EAsr!  
"H$@b`)  
\ADLMj`F|  
public class Utility { <<sE`>)  
#jm@N7OZ  
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public Utility() x)_r@l`$ix  
{ NJm-%K  
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\s
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} dZD
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Z%OW5]q  
//线程睡眠 b)`pZiQP  
public static void sleep(int nSecond) >Mw'eQ0(y  
{ ws[/  
try{ 7E\g &R.  
Thread.sleep(nSecond); T)~!mifX  
} \2>3Opt  
catch(Exception e) #|?8~c;RWG  
{ (0R2T"/  
e.printStackTrace (); xp^ 7#`MJ?  
} e1UITjy  
} x6v,lR  
p?kvW42/  
//日志 ^KbL ,T  
public static void log(String sMsg) [S0mY["  
{ !D;c,{Oz  
System.err.println(sMsg); ?A&%Cwj  
} G|*G9nQ  
7&foEJ3q  
xNIGO/uI~  
public static void log(int sMsg) +{e`]t>_  
{ R5ZIC4p  
System.err.println(sMsg); -=mwy  
} VE$t%QT  
} j8a[
(  
g YUTt  
7 >bMzdH  
/* "mA1H]r3  
**TestMethod.java +>}o;`
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*/ R$d7\nBG  
package NetFox; |IN[uQ  
1'fb @vO  
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public class TestMethod { Du!._  
%Kl(>{N  
/[{auUxSX  
public TestMethod() +GeWg` \=  
{ ///xx/weblogic60b2_win.exe `*k@4.J{  
try{ 'Wp@b678  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); dp<$Zw8BE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vBoO'l9'M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9yL6W'B!  
fileFetch.start(); \=fh-c(J,  
} q:]Q% IC^  
catch(Exception e){e.printStackTrace ();} OaaH$B  
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J|5Ay1eF-  
} #U"1 9@|}  
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public static void main(String[] args) BIj   
{ Dr+
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new TestMethod(); 12OlrU  
} 30d#Lq  
} Mk5RHDh  
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