http断点续传简单实现（java)

/* %98' @$:0  
**SiteFileFetch.java 0`.
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*/ m42T9wSsx  
package NetFox; ^2d!*W|  
import java.io.*; AT2v!mNyCw  
import java.net.*; %:>3n8n  
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public class SiteFileFetch extends Thread { ^ &E}r{?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean OJT1d-5p  
long[] nStartPos; //开始位置 YzosZ! L!<  
long[] nEndPos; //结束位置 dpQG[vXe  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 { pu85'DV  
long nFileLength; //文件长度 4${jr\q]  
boolean bFirst = true; //是否第一次取文件 ~DO4,  
boolean bStop = false; //停止标志 tMj;s^P1  
File tmpFile; //文件下载的临时信息 s,bERN7'yO  
DataOutputStream output; //输出到文件的输出流 j.a`N2]WE  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ZnFi<@UB)  
public SiteFileFetch(SiteInfoBean bean) throws IOException W{z.?$SH  
{ G6V
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siteInfoBean = bean; &<zd.~N"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); gh`m*@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `&0Wv0D0  
if(tmpFile.exists ()) ]v[|B  
{ T|&[7%F3"  
bFirst = false; 6cqP2!~  
read_nPos(); bNT9 H`P  
} l1ZY1#%j  
else PcB_oG g  
{ f>BWG`  
nStartPos = new long[bean.getNSplitter()]; F4=}}k
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nEndPos = new long[bean.getNSplitter()]; |+ N5z  
} )
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} vVGDDDz/  
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public void run() ' |-JWH  
{ wf,7==  
//获得文件长度 '=][J_
 
//分割文件 ~['Kgh_;  
//实例FileSplitterFetch /iG*)6*^k  
//启动FileSplitterFetch线程 Gm*X'[\DD  
//等待子线程返回 1[_mEtM:]B  
try{ w
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if(bFirst) oJ#
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{ at2FmBdu C  
nFileLength = getFileSize(); UR:aD_h  
if(nFileLength == -1) m*e{\)rd#  
{ zy*/T>{#  
System.err.println("File Length is not known!"); -}K<ni6  
} 9&<x17'  
else if(nFileLength == -2) B|o2K}%f  
{ BL@:!t  
System.err.println("File is not access!"); #plY\0E@  
} JNcYJ[wqv  
else VDTcR  
{ KfF!{g f  
for(int i=0;i<nStartPos.length;i++)
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{ Uye|9/w8 !  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); S/;bU:  
} 9Fn\FYUq  
for(int i=0;i<nEndPos.length-1;i++) Dk48@`l2  
{ V I% 6.6D  
nEndPos = nStartPos[i+1]; U]a*uF~h  
} ){jla,[  
nEndPos[nEndPos.length-1] = nFileLength; 8Lw B B  
} mN8pg4  
} F R|&^j6  
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//启动子线程 E*i#?u  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _X?^Cy  
for(int i=0;i<nStartPos.length;i++) ctcS:<r/3@  
{ V|\7')Qq  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qZ@s#UiB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @k&qb!Qah  
nStartPos,nEndPos,i); GfC5z n>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6'xsG?{JY  
fileSplitterFetch.start(); N&@}/wzZ  
} gv5*!eI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q_l'o3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !ct4;.2 D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", I-OJVZ( V  
nEndPos = " + nFileLength); a22XDes=  
// fileSplitterFetch[nPos.length-1].start(); q+,Q<2J  
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4@xE8`+bG  
//等待子线程结束 1?Z4K/  
//int count = 0; ;;&}5jc
V  
//是否结束while循环 hlt[\LP=$  
boolean breakWhile = false; n_'{^6*O  
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while(!bStop) Z0l+1iMx  
{ K_&4D'  
write_nPos(); QY== GfHt  
Utility.sleep(500); Y3Q9=u*5  
breakWhile = true; 4j)tfhwd8  
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for(int i=0;i<nStartPos.length;i++) \6\<~UX^  
{ qP<Lr)nUH  
if(!fileSplitterFetch.bDownOver) v0L\0&+  
{ &c1A*Pl/:G  
breakWhile = false; dO%W+K  
break; 7 [0L9\xm  
} sJNFFOz  
} $ MC)}l  
if(breakWhile) 5atYOep  
break; 8_N]e'WUh  
;| 1$Q!4  
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//count++;  O#I1V K  
//if(count>4) z;y:9l  
// siteStop(); 3po:xMY  
} IsR!'%Pu  
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System.err.println("文件下载结束！"); _o8?E&d  
} o=1
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catch(Exception e){e.printStackTrace ();} /&4U6a  
} X]y)qV)a[c  
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//获得文件长度 W5R\Q,x6  
public long getFileSize() }u1O#L}F5  
{ MHa#?Q9  
int nFileLength = -1; NF? vg/{  
try{ CD8}I85K  
URL url = new URL(siteInfoBean.getSSiteURL()); mx=BD'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vhhC> 7  
httpConnection.setRequestProperty("User-Agent","NetFox"); h yv2SxP*  
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int responseCode=httpConnection.getResponseCode();

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if(responseCode>=400) =z8f]/k*>  
{ i7ly[6{^pr  
processErrorCode(responseCode); VH:]@x//{  
return -2; //-2 represent access is error Od|$Y+@6  
} #^]n0!  
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String sHeader; z<5m fAm  
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for(int i=1;;i++) Qa.uMq  
{ &y#r;L<9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /soKucN"h  
//Utility.log(in.readLine()); @$z<i `4  
sHeader=httpConnection.getHeaderFieldKey(i); & GreN  
if(sHeader!=null) 1m.W<  
{ 'g{9@PkGn  
if(sHeader.equals("Content-Length")) e zOj+vz  
{ }[xs~!2F  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <'g:T
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break;
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} JwXT%op9RP  
} `[n("7,  
else %$DI^yS  
break; =yy5D$\  
} 9`9R!=NM  
} h*<P$t  
catch(IOException e){e.printStackTrace ();} wKsT7c'  
catch(Exception e){e.printStackTrace ();} ki)#d' }  
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Utility.log(nFileLength); [0D Et  
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return nFileLength; >i
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} 9WR6!.y#f  
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//保存下载信息（文件指针位置） gatB QwJb9  
private void write_nPos() cA:*V|YV`  
{ mbueP.q[?  
try{ >&U,co$>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); pn^ d]rou?  
output.writeInt(nStartPos.length); rX1QMR7?  
for(int i=0;i<nStartPos.length;i++) nt@aYXK4|  
{ T|TO}_x  
// output.writeLong(nPos); +="e]Yh;  
output.writeLong(fileSplitterFetch.nStartPos); |u;v27  
output.writeLong(fileSplitterFetch.nEndPos); qQH]`#P  
} @qHNE,K  
output.close(); 6!(@@^7{*  
} ~b2wBs)r  
catch(IOException e){e.printStackTrace ();} ,zTy?OQ  
catch(Exception e){e.printStackTrace ();} (zFi$  
} k Zq!&  
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//读取保存的下载信息（文件指针位置） L{`JRu  
private void read_nPos() E)fglYWs2  
{ s91JBP|B7  
try{ UMcgdJB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); z.I9wQ]X[  
int nCount = input.readInt(); /n8B,-Z5s5  
nStartPos = new long[nCount]; '3 ^+{=q  
nEndPos = new long[nCount]; RnDt)3  
for(int i=0;i<nStartPos.length;i++) 5O6hxcMjT  
{ Dv/WE>?Aw  
nStartPos = input.readLong(); D N*t~Z3[  
nEndPos = input.readLong(); eh5gjSqx  
} 0p\@!Z H  
input.close(); I2nhqJy^  
} I'0@viF"Nx  
catch(IOException e){e.printStackTrace ();} qC?:*CXH  
catch(Exception e){e.printStackTrace ();} b 'pOJ
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} J>bJ 449B  
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private void processErrorCode(int nErrorCode) >:|q&|x-  
{ >#y^;/bb  
System.err.println("Error Code : " + nErrorCode); bAm(8nT7w  
} EB8\_]6XJ  
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//停止文件下载 .?Gd'Lp  
public void siteStop() #gcF"L||  
{ =Yt R`  
bStop = true; #*(td<Cp  
for(int i=0;i<nStartPos.length;i++) 5EebPXBzB  
fileSplitterFetch.splitterStop(); $+I;oHWI  
^~A>8CQOU  
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} AlIpsJ[UU  
} Q(oN/y3,  
//负责部分文件的抓取 y7i*s^ys{  
**FileSplitterFetch.java K]9"_UnN  
*/ k4[|'Dk?  
package NetFox; d$Pab*  
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import java.io.*; `6xkf&Kt  
import java.net.*; lh;:M-b9  
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public class FileSplitterFetch extends Thread { SK#(#OQoh  
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String sURL; //File URL 6gs01c,BA  
long nStartPos; //File Snippet Start Position  #c66)  
long nEndPos; //File Snippet End Position |YY_^C`"-  
int nThreadID; //Thread's ID ]f({`&K5  
boolean bDownOver = false; //Downing is over ]&pds\  
boolean bStop = false; //Stop identical M!XsJ<jN/  
FileAccessI fileAccessI = null; //File Access interface z=3\Ab  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u!W0P6   
{ M%kO7>h8  
this.sURL = sURL; Oz%>/zw[h
 
this.nStartPos = nStart; X'qU*Eo  
this.nEndPos = nEnd; jmFz51  
nThreadID = id; l|k`YC x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4Q6mo/=H  
} &?yZv{  
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public void run() `I,,C,{C  
{ n*{sTT  
while(nStartPos < nEndPos && !bStop) <t \H^H!  
{  N#a$t&  
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try{ 3 C<L  
URL url = new URL(sURL); cZ2kYn8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [CXrSST")E  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?3.b{Cq{-  
String sProperty = "bytes="+nStartPos+"-"; j?x>_#tIY  
httpConnection.setRequestProperty("RANGE",sProperty); +yD`3` E  
Utility.log(sProperty); <,e+ kL{  
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InputStream input = httpConnection.getInputStream(); <yNM%P<Oy  
//logResponseHead(httpConnection); V13N}]  
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byte[] b = new byte[1024]; vbC\?\_  
int nRead; W1|0Yd ;P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) K#=*9S  
{ EH! q=&d  
nStartPos += fileAccessI.write(b,0,nRead); < F.hZGss7  
//if(nThreadID == 1) 3GhRWB-U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !~rY1T~  
} NP/Gn6fr  
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Utility.log("Thread " + nThreadID + " is over!"); A"G 1^8wvX  
bDownOver = true; ^Uf]Q$uCjE  
//nPos = fileAccessI.write (b,0,nRead); G'ei/Me6{  
} [Q/TlOt5  
catch(Exception e){e.printStackTrace ();} ov_j4j>6P  
} j;-1J_e5  
} rFj-kojg  
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//打印回应的头信息 |6K+E6H  
public void logResponseHead(HttpURLConnection con) Z:sg}  
{ 5',8 ziJQ  
for(int i=1;;i++) V`XNDNJ:  
{ @W[f1  
String header=con.getHeaderFieldKey(i); rLI8pA|.  
if(header!=null) Y6zbo
  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <~n"m  
Utility.log(header+" : "+con.getHeaderField(header)); %&w3;d;c  
else sP;nGQ.eN  
break; 0;AA/  
} hPUYyjXPB  
} 1+jAz`nA:T  
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}dWq=)*  
public void splitterStop()
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{ 7!EBH(,z  
bStop = true; kT"Kyd  
} Q;43[1&3w  
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} / zB0J?  
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/* QgU8s'e  
**FileAccess.java tG9BfGF  
*//文件访问(定位，写) jv%kOovj  
package NetFox; 17oa69G  
import java.io.*; T`\x
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public class FileAccessI implements Serializable{ %_RQx2  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \{Z;:,S  
RandomAccessFile oSavedFile; LcSX*M
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long nPos; ?'@8kpb  
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public FileAccessI() throws IOException Mc09ES  
{ q Gw -tPD<  
this("",0); C":32_q  
} -0$55pa/@:  
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public FileAccessI(String sName,long nPos) throws IOException #fM#p+v  
{ P"y`A}Bx  
oSavedFile = new RandomAccessFile(sName,"rw"); ~sl{|E  
this.nPos = nPos; OjJXysslXO  
oSavedFile.seek(nPos); -@yh>8v  
} 7\$qFF-y  
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public synchronized int write(byte[] b,int nStart,int nLen) u frW\X  
{ tyXuG<  
int n = -1; Zhh2v>QOy  
try{ s>;v!^N?u  
oSavedFile.write(b,nStart,nLen); &x[E;P*Fg  
n = nLen; L+Xc-uv["p  
} < Z{HX[y  
catch(IOException e) 2XFU1 AW  
{ xO^:_8=&:  
e.printStackTrace (); 5p<ItU$pnL  
} !UG 7Uer  
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return n; W-x?:X<}  
} { /K.3  
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} K`iv c N"  
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/* ])|d"[ur=  
**SiteInfoBean.java CdasP9"1  
*/ U=DmsnD,  
package NetFox; ]h>_\9qO  
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public class SiteInfoBean { p2n0Z\2  
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private String sSiteURL; //Site's URL ),UX4%K=  
private String sFilePath; //Saved File's Path As3.Q(#Z  
private String sFileName; //Saved File's Name U]^HjfX\  
private int nSplitter; //Count of Splited Downloading File 4{hps.$?~  
xIxn"^'  
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public SiteInfoBean() ofPHmh`  
{//nSplitter的缺省值为5 :"=ez<t  
//default value of nSplitter is 5 CK,7^U  
this("","","",5); D2](da:]8)  
} W=#:.Xj[  
bu:S:`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (d(hR0HKE  
{ ue4Vcf  
sSiteURL= sURL; +Vm}E0Ov  
sFilePath = sPath; [`^a=:*  
sFileName = sName; &j4xgh9  
this.nSplitter = nSpiltter; }\HN&@  
^aH\7J@Y  
\hBG<nH{0  
} |+iws8xK?  
A6:es_  
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public String getSSiteURL() ^Wc@oa`  
{ 9cf:pXMi  
return sSiteURL; G]+&!4  
} k p<OJy  
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public void setSSiteURL(String value) ptDY3n~'  
{ ;.TRWn#  
sSiteURL = value; X:6c}p%,!  
} *^f<W6xc  
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public String getSFilePath() [-\%4  
{ &K.?p2$X  
return sFilePath; OY:
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}  ~ ip,Nl  
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public void setSFilePath(String value) c17_2 @N  
{ f7=((
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sFilePath = value; pgOQIzu  
} /4g1zrU
  
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public String getSFileName() !{^PO<9  
{ .u4 W /  
return sFileName; z"0I>gl  
} (>r[-Bft  
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public void setSFileName(String value) .w0s%T,8}^  
{ oZ!m  
sFileName = value; M+w=O!dq  
} h&--,A >  
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public int getNSplitter() yt.F\[1  
{ i(>4wK!!  
return nSplitter; ;*:Pw?'  
} tE)suU5Y  
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public void setNSplitter(int nCount) dvt9u9Vg=  
{ q U]gj@R  
nSplitter = nCount; kzt(i Y_6  
} <})2#sZO!  
} w-Da~[J  
v"#mzd.tW  
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/* k +H3Bq  
**Utility.java (=* cK-3  
*/ YbTxn="_  
package NetFox; H;YP8MoQ  
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public class Utility { `/EGyN6X  
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public Utility() wid;8%m  
{ &N
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} J6L K  
*#tJM.Z  
//线程睡眠 <gJU?$  
public static void sleep(int nSecond) RPE5K:P  
{ QA5QweL  
try{ dIRm q+d^  
Thread.sleep(nSecond); Qj.l:9%  
} V3c l~  
catch(Exception e) ?<(m 5Al7  
{ ]>~)<   
e.printStackTrace (); M;p em<  
} kH
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} Z; A`oKd  
V`bi&1?6\  
//日志 5A s
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public static void log(String sMsg) =gJb^ Gx(w  
{ ,'p2v)p^4  
System.err.println(sMsg); rzh#CnL3  
} pO ml8SQf  
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t4-pM1]1_  
public static void log(int sMsg) m6',SY9T  
{ ?sMP~RHQ  
System.err.println(sMsg); -5I2
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} 2Fq<*pxAY  
} BPdfYu,il  
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/* )FpZPdN+h  
**TestMethod.java +;#Y]xy:  
*/ { Fawt:  
package NetFox; " e}3:U5n  
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r9 !Tug*>m  
public class TestMethod { /4vG3  
)*,5"CO  
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public TestMethod() >]W)'lnO  
{ ///xx/weblogic60b2_win.exe > 3&: 5  
try{ "87ghj_}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2U; t(,dn'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
pb$~b\s]=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z| V`B `  
fileFetch.start(); EpFQ|.mQ  
} WC|.g,9#  
catch(Exception e){e.printStackTrace ();} *{yK 8  
{6~l$  
[]A%<EI7  
} dO4
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public static void main(String[] args)  \o/n  
{ |Tm!VFd  
new TestMethod(); DBT&
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} ^9ePfF)5  
} F$hYKT2|  
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