http断点续传简单实现（java)

/* ffI=Bt]t  
**SiteFileFetch.java 'xG{q+jj'  
*/ toU<InN  
package NetFox; EqBTN07dZS  
import java.io.*; YnU*MC}  
import java.net.*; <Vt"%C  
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public class SiteFileFetch extends Thread { X]2x0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean YADXXQ"
 
long[] nStartPos; //开始位置 xEq?[M  
long[] nEndPos; //结束位置 O`!XW8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ml)\RL  
long nFileLength; //文件长度 #N|JC d_  
boolean bFirst = true; //是否第一次取文件 ,y-!h@(  
boolean bStop = false; //停止标志 ? 47"$=G  
File tmpFile; //文件下载的临时信息 ' Qlj"U  
DataOutputStream output; //输出到文件的输出流 f6\4,()  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） mBB"e
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public SiteFileFetch(SiteInfoBean bean) throws IOException ;*+H&  
{ !M)] 1Y
 
siteInfoBean = bean; uT=5zu  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *aFh*-Sj2I  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (["V( $  
if(tmpFile.exists ()) oO7)7$|1  
{ ang~_Ec.  
bFirst = false; NYKYj`K  
read_nPos(); ;gAL_/_  
} B7Zi|-F
  
else BW3Q03SW6  
{ b&Laxki  
nStartPos = new long[bean.getNSplitter()]; 2dB]Lw@s  
nEndPos = new long[bean.getNSplitter()]; K:VZ#U(_  
} B>S>t5$  
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} xh#pw2v7V  
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public void run() cdGBo4  
{  V_
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//获得文件长度 RU/SJ1wM"  
//分割文件 I#]pk!  
//实例FileSplitterFetch 6f t6;*,  
//启动FileSplitterFetch线程 >Y\?v-^~;  
//等待子线程返回 OwNo$b]h`  
try{ @.)[U:N  
if(bFirst) xzFQ)t&  
{ [wJ\.9<Oa  
nFileLength = getFileSize(); PRBlf  
if(nFileLength == -1) =w:)AWZ  
{ o9C#5%9  
System.err.println("File Length is not known!"); +M#}(hK  
} A@:U|)+4  
else if(nFileLength == -2) Nq6; z)$  
{ !&.-{ _$  
System.err.println("File is not access!"); i6P$>8jBQ-  
} e^x%d[sU  
else '.gi@Sr5  
{ pp{p4Z   
for(int i=0;i<nStartPos.length;i++) DvLwX1(l  
{ +7AH|v8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); CY*GCkH  
} i{:iRUC#  
for(int i=0;i<nEndPos.length-1;i++) cF EO}  
{ YdIZikF#  
nEndPos = nStartPos[i+1]; 19[!9ci  
} +%WW8OX  
nEndPos[nEndPos.length-1] = nFileLength; j/NX
 
} p&4n"hC  
} <5#2^
(  
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 T-+ uQ3  
//启动子线程 'n\PS,[1R  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Hr7pcz/#l  
for(int i=0;i<nStartPos.length;i++) mb%U~Na  
{ =}I=s@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Aeo=m}C;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9x8Vsd  
nStartPos,nEndPos,i); %BT]h3dcSS  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u~JR]T  
fileSplitterFetch.start(); a({N}ZDo  
} Ro `Xs.X  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =1VZcLNt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rQ2TPX<?a  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !mB `FC  
nEndPos = " + nFileLength); C?W}/r[  
// fileSplitterFetch[nPos.length-1].start(); 1{a4zGE?[  
p8?"}  
nqTOAL9FF  
//等待子线程结束 z[O*f#t  
//int count = 0; vCK+v r!  
//是否结束while循环 KDV.ZSF7  
boolean breakWhile = false; a0PU&o1EF  
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while(!bStop) !"-.D4*r  
{ iTT%_-X-  
write_nPos(); %""h:1/S  
Utility.sleep(500); OjG`s-91&  
breakWhile = true; }*C  
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for(int i=0;i<nStartPos.length;i++) 8$Zwk7 w8A  
{ m~P30)  
if(!fileSplitterFetch.bDownOver) =w"Kkj>%oh  
{ /;[x3}[  
breakWhile = false; c^puz2  
break; 
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} _V0%JE'  
} D:z_F
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if(breakWhile) R?tjobk!  
break; + 660/ e8N  
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//count++; R7!v=X]i  
//if(count>4) ?2\oi*$  
// siteStop(); Qgv g*KX  
} D/;[x{;E  
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System.err.println("文件下载结束！"); bu $u@:q 6  
} Zg>]!^X8  
catch(Exception e){e.printStackTrace ();} J~oxqw}  
} 2dHsM'ze  
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* {~`Lw)y  
//获得文件长度 +9pock  
public long getFileSize() /eXiWasQ  
{ W2zG"Q  
int nFileLength = -1; ,`k6@4  
try{ /(u? k%Q  
URL url = new URL(siteInfoBean.getSSiteURL()); VZ">vIRyi|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'iOaj0f  
httpConnection.setRequestProperty("User-Agent","NetFox"); @$;8k }  
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int responseCode=httpConnection.getResponseCode(); o`7 Z<HF  
if(responseCode>=400) ZH>i2|W<  
{ =YfzB!ld  
processErrorCode(responseCode); j(K)CHH  
return -2; //-2 represent access is error FUJ<gqL  
} rwio>4=  
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String sHeader; 4i}nk T  
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for(int i=1;;i++) 6%:~.ZfN  
{ ?$uF(>LD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _Ex<VF u  
//Utility.log(in.readLine()); #a2Z.a<V  
sHeader=httpConnection.getHeaderFieldKey(i); 3hje  
if(sHeader!=null) ?,+&NX3m  
{ 'jO8C2Th%  
if(sHeader.equals("Content-Length")) l]Xbd{  
{ B4*y-Q.*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xO<%lq`  
break; !_~/Y/M  
} _5(1T%K)  
} +xsGa{`  
else "USzk7=&.  
break; ocMTTVo  
} v0=v1G*rvJ  
} c#1kg@q@  
catch(IOException e){e.printStackTrace ();} ~RwoktO  
catch(Exception e){e.printStackTrace ();} YjJ^SU`*  
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Utility.log(nFileLength); 3/uvw>$  
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return nFileLength; %g89eaEZ  
} B!8X?8D  
8faT@J'e;  
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//保存下载信息（文件指针位置） !<VP[%2L~  
private void write_nPos() 2Ub-uf
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{ Li0+%ijM  
try{ :RJo#ape  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Qy}pn=#Q  
output.writeInt(nStartPos.length); i+< v7?:`#  
for(int i=0;i<nStartPos.length;i++) T<b*=i  
{ /vi Ic %=  
// output.writeLong(nPos); ~Cw7.NA{3  
output.writeLong(fileSplitterFetch.nStartPos); Kng=v~)N'  
output.writeLong(fileSplitterFetch.nEndPos); o"z;k3(i$7  
} S')
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output.close(); hA1B C3  
} Z]bG"K3l  
catch(IOException e){e.printStackTrace ();} {<gX~./]c  
catch(Exception e){e.printStackTrace ();} e{Vn{.i,5  
} ,F`1VpTd8  
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//读取保存的下载信息（文件指针位置） &V
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private void read_nPos() Kb;Pd!Q  
{ wgolgof  
try{ x _d   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); gd#?rc*f<3  
int nCount = input.readInt(); M8\/[R\  
nStartPos = new long[nCount]; v@8SMOe%  
nEndPos = new long[nCount]; a}|<*!4zUQ  
for(int i=0;i<nStartPos.length;i++) 9IrCu?n9b  
{ Mqk|H~l5c  
nStartPos = input.readLong(); M"{*))O\-c  
nEndPos = input.readLong(); tq@)J_7|  
} eY^zs0  
input.close(); -%P}LaC<  
} <exyd6iI  
catch(IOException e){e.printStackTrace ();} >SziRm>Y7  
catch(Exception e){e.printStackTrace ();} 9=/4}!.  
} =OV5DmVmQ  
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private void processErrorCode(int nErrorCode) Z)=S>06X Q  
{ .3n\~Sn  
System.err.println("Error Code : " + nErrorCode); i O?f&u  
} `,/5skeJ  
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//停止文件下载 G|-RscPe  
public void siteStop() _h,_HW)G  
{ 3fXrwmBT8  
bStop = true; c+T`X?.j  
for(int i=0;i<nStartPos.length;i++) YRf$?xa  
fileSplitterFetch.splitterStop(); +oO7UWs>6  
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} K7(k_4  
} >hq{:m  
//负责部分文件的抓取 O'#;Ge/,  
**FileSplitterFetch.java j%Z5[{!/,X  
*/ C2=PGq  
package NetFox; iQG]v[$  
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h)j#?\KYm9  
import java.io.*; 3vAP&i'I  
import java.net.*; <gH-`3J6  
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public class FileSplitterFetch extends Thread { F0zaA  
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String sURL; //File URL qTwl\dcncC  
long nStartPos; //File Snippet Start Position n@"<NKzh  
long nEndPos; //File Snippet End Position mvt-+K?U  
int nThreadID; //Thread's ID y:$qX*+9e  
boolean bDownOver = false; //Downing is over 9,\AAISi  
boolean bStop = false; //Stop identical q+<,FdG  
FileAccessI fileAccessI = null; //File Access interface $?gKIv>g  
(Pw,3CbJ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Otq1CD9  
{ D8PC;@m  
this.sURL = sURL; L\
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this.nStartPos = nStart;
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this.nEndPos = nEnd; B1E:P`t  
nThreadID = id; ^J^FGo|M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *14:^neoI  
} -O=xgvh"  
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public void run() {YrA[9  
{ c'Ibgfx%
m  
while(nStartPos < nEndPos && !bStop) oAB:H\  
{ `nEqw/I  
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try{ AS~!YR  
URL url = new URL(sURL); %{:pBt:Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h<$%y(lP  
httpConnection.setRequestProperty("User-Agent","NetFox"); &sBD0R(a  
String sProperty = "bytes="+nStartPos+"-"; opN4@a7l  
httpConnection.setRequestProperty("RANGE",sProperty); QLHEzEvf{/  
Utility.log(sProperty); <n~.X<6V'  
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InputStream input = httpConnection.getInputStream(); ~7g$TAe{  
//logResponseHead(httpConnection); 8Exky^OT|  
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byte[] b = new byte[1024]; V\r{6-%XiW  
int nRead; 4t/?b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) r%X M`;bQX  
{ W7_m,{q  
nStartPos += fileAccessI.write(b,0,nRead); VnB HQ.C  
//if(nThreadID == 1) EowzEGq!a5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _!Tjb^  
} <Uf`'X\e6  
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Utility.log("Thread " + nThreadID + " is over!"); P(Zj}tGN  
bDownOver = true; 8==M{M/eM  
//nPos = fileAccessI.write (b,0,nRead); k W 8>VnW  
} d^!3&y&  
catch(Exception e){e.printStackTrace ();} RIO?rt;  
} Y= =5\;-  
} l.Ev]G/5  
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//打印回应的头信息 .Z"`:4O  
public void logResponseHead(HttpURLConnection con) CRNi
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{ hm0A%J
s  
for(int i=1;;i++) I} +up,B]o  
{ um_J%v6ER  
String header=con.getHeaderFieldKey(i); y3QS!3I  
if(header!=null) !io1~GpKS  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;C:|m7|  
Utility.log(header+" : "+con.getHeaderField(header)); 59W~bWHCP  
else t#y,9>6  
break; HyKA+7}  
} 1n7'\esC*  
} $G }9iV7  
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public void splitterStop() P{_%p<:V  
{ *vIP\NL?H  
bStop = true; K[/L!.Ag  
} :?FHqfN?_  
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} >BK/HuS  
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/* x^pt^KR;  
**FileAccess.java #G`K<%{
?f  
*//文件访问(定位，写) 5VQ-D`kE+  
package NetFox; H8dS]N~[Y  
import java.io.*; :i0;jWcb  
*!*%~h8V  
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public class FileAccessI implements Serializable{ .oTS7rYw  
t)?K@{ 9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Y`4 LMK[]  
RandomAccessFile oSavedFile; J=: \b  
long nPos; Q^3{L\6_  
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public FileAccessI() throws IOException 6J}Yr5oD  
{ 6vps`k$,~  
this("",0); nHq4f&(H  
} +,$pcf<[V  
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public FileAccessI(String sName,long nPos) throws IOException zb"4_L@m2  
{ .j^BWr  
oSavedFile = new RandomAccessFile(sName,"rw"); T{m) = (q  
this.nPos = nPos; $0un`&W  
oSavedFile.seek(nPos); S ~fz  
} =2=rPZw9  
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public synchronized int write(byte[] b,int nStart,int nLen) CxJ3u  
{ w{k^O7
~  
int n = -1; JsuI&v  
try{ +Ss3Ph  
oSavedFile.write(b,nStart,nLen); /BQqg08@L  
n = nLen; Umzb  
} >$-YNZA   
catch(IOException e) 4cPZGZ{U  
{ q
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e.printStackTrace (); OgC,oj,!/  
} /je $+  
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return n; kN{$-v=K  
} ISK 8t  
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} uPr!;'J=  
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;s3\Z^h4kd  
/* eiyr^Sch.  
**SiteInfoBean.java GI,TE  
*/ WG\ _eRj  
package NetFox; w%iwxo  
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public class SiteInfoBean { #Ktk["6  
*>mjUT}cP  
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private String sSiteURL; //Site's URL d4^x,hzV  
private String sFilePath; //Saved File's Path =7H\llL4BC  
private String sFileName; //Saved File's Name _&9P&Zf4  
private int nSplitter; //Count of Splited Downloading File [TUs^%2@  
7qUg~GJX  
 +PADy8  
public SiteInfoBean() \~+b&  
{//nSplitter的缺省值为5 8OV=;aM?{  
//default value of nSplitter is 5 vWM&4|Q1~  
this("","","",5); 0,0Z!-Y  
} 'Q:%s  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Kb{&a  
{ U5~aG!E  
sSiteURL= sURL; 6S3D#SY  
sFilePath = sPath; ;]m;p,$  
sFileName = sName; :Rv+Bm  
this.nSplitter = nSpiltter; )AR-b8..o  
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} {6RA~  
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public String getSSiteURL() 9{j`eAUZl  
{ lZ[J1:%  
return sSiteURL; |? fAe{*  
} c_+fA  
6fI2y4yEz  
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public void setSSiteURL(String value) _/}$X"4  
{ Et(H6O8  
sSiteURL = value; j nSZ@u  
} H'/V<
%  
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public String getSFilePath() X@tA+  
{ I(7iD. ^:  
return sFilePath; 
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} ]S@T|08b  
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public void setSFilePath(String value) $!9/s S?  
{ Z]TQ+9t  
sFilePath = value; aZ\Z7(  
} ^w``(-[*  
>#;;g2UV  
 WTl0}wi  
public String getSFileName() SSE,G!@
 
{ O{\<Izm`D  
return sFileName; U; <{P  
} uuF~+=.|  
W% Lrp{  
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public void setSFileName(String value) {Ke IYjE  
{ +$(y2F7|u-  
sFileName = value; wA/!A$v(  
} uuD2O )v  
\I4Uj.'>\  
1D8S}=5&  
public int getNSplitter() CPcUB4a%#  
{ %@)q=*=y  
return nSplitter; ONcLhwH  
} _eBNbO_J  
JLoE)\Mi  
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public void setNSplitter(int nCount) L&:A59)1k  
{ Vraz}JV  
nSplitter = nCount; nFGX2|d  
} 4 Sk@ v  
} c1+z(NQ3  
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/* l$c/!V[3  
**Utility.java iWr #H  
*/ /c-k{5mH%  
package NetFox; L?0IUGY  
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Ph.RWy")  
public class Utility { S[
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G"u4]!$/  
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public Utility() x$TLj  
{ wG)[Ik6:  
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} }{:}K<  
Y`-q[F?\y  
//线程睡眠 ]|w~{X!b4  
public static void sleep(int nSecond) L1Yj9i
 
{ m zoH$@  
try{ Nr,I`x\N
 
Thread.sleep(nSecond); z4(\yx  
} _1$
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catch(Exception e) yW7>5r  
{ *,O3@,+>H  
e.printStackTrace (); 9lGa*f)  
} X_D-K F  
} f]?&R c2C  
06.8m;{N  
//日志 w^nA/=;r  
public static void log(String sMsg) `VGw5o  
{ Th\T$T`X$  
System.err.println(sMsg); '4u/g  
} &X` lh P  
tK*y/S  
Rb:?%\=  
public static void log(int sMsg) knV*,   
{ oVbs^sbRH  
System.err.println(sMsg); A(`Mwh+  
} |+sAqx1IF  
} p}gA8o  
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/* N z=P1&G'  
**TestMethod.java v<l]K$5J&  
*/ KY%qzq,n  
package NetFox; a#CjGj)  
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UMD\n<+cG,  
public class TestMethod { x00'wY|  
wnXU=  
!m'R
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public TestMethod() XA.1Y)  
{ ///xx/weblogic60b2_win.exe DXO'MZon3  
try{ \fI05GZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *L*{FnsV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); })(robBkA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !-%%94Q  
fileFetch.start(); *nHMQ/uf  
} FoZI0p?L)9  
catch(Exception e){e.printStackTrace ();} l>s@&%;Mg  
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} +N2ILE8[<  
g@/}SJh/>  
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public static void main(String[] args) xy&*s\=:  
{ wzoT!-_X  
new TestMethod(); PX/^*  
} K~3Y8ca  
} pg_H'0R  
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