http断点续传简单实现（java)

/* 93Qx+oK]  
**SiteFileFetch.java _eaK:EW  
*/ 3HX-lg`0  
package NetFox; hXn@vK6  
import java.io.*; S'AS,'EnY  
import java.net.*; Vjr}"K$Y  
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public class SiteFileFetch extends Thread { ery{>|k  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1swqs7rR|  
long[] nStartPos; //开始位置 BOW`{=  
long[] nEndPos; //结束位置 Vdf~rV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 e= _7Q.cn  
long nFileLength; //文件长度 xa%2w]  
boolean bFirst = true; //是否第一次取文件 J)=Ts({  
boolean bStop = false; //停止标志 =Xb:.  
File tmpFile; //文件下载的临时信息 ,V=]QHcg  
DataOutputStream output; //输出到文件的输出流 95 X6
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） DGx<Nys@B  
public SiteFileFetch(SiteInfoBean bean) throws IOException "& q])3h=  
{ J`A )WsKkb  
siteInfoBean = bean; xgB-m[Xi  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 'C1yqkIa`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xO'xZ%cUI  
if(tmpFile.exists ()) A)o%\j  
{ f<2<8xS  
bFirst = false; G%fNGQwT  
read_nPos(); Kdb:Q0B  
} \F),SL  
else _~E_#cNn  
{ 0Y ld!L  
nStartPos = new long[bean.getNSplitter()]; ltG|#(  
nEndPos = new long[bean.getNSplitter()]; k|_LF[*Z  
} ^9*Jz{e  
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} 7.1FRxS  
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public void run() 1cPjgBxv#  
{ qu0dWgK
 
//获得文件长度 =doOt 7Rj  
//分割文件 j2,w1f}T  
//实例FileSplitterFetch NpxND0  
//启动FileSplitterFetch线程 DP7B X^e  
//等待子线程返回 >W@3_{0  
try{ >WW5;7$  
if(bFirst) 9TOq
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{ yDBMm^  
nFileLength = getFileSize(); &GLe4zEh  
if(nFileLength == -1) }q[IhjD%  
{ CjlA"_!%E  
System.err.println("File Length is not known!"); ao)8ie
 
} E@^mlUf  
else if(nFileLength == -2) `}&}2k  
{ LDq(WPI1#  
System.err.println("File is not access!"); &$E.rgtg  
} )u(Dqu\t  
else bmGtYv  
{ GxcW^{;  
for(int i=0;i<nStartPos.length;i++) 5_Opx=  
{ ALnE[}N6,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5Lm<3:7Q+  
} 3r,^is  
for(int i=0;i<nEndPos.length-1;i++) /s~&$(d59o  
{ \I`g[nT|  
nEndPos = nStartPos[i+1]; e't1.%w  
} .2:S0=xt<  
nEndPos[nEndPos.length-1] = nFileLength; 3k?|-js  
} XYsU)(;j  
} ]h_V5rdX@  
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//启动子线程 e`D?x1-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; qx\P(dOUf  
for(int i=0;i<nStartPos.length;i++) :~+m9r  
{ w?zY9Fs=s  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tR% &.,2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), B< BS>(Nr>  
nStartPos,nEndPos,i); >4eZ%</D5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R?GF,s<j  
fileSplitterFetch.start(); :yC|Q)  
} WL/9r *jW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YO^iEI.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W0>fu>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )MJy  
nEndPos = " + nFileLength); GjvTYg~  
// fileSplitterFetch[nPos.length-1].start(); $>y   
'2.11cM3  
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//等待子线程结束 maTZNzy  
//int count = 0; _Zs]za.#)|  
//是否结束while循环
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boolean breakWhile = false; *Me{G y  
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while(!bStop) !`F^LXGA  
{ @s/0 .7  
write_nPos(); hz_F^gF  
Utility.sleep(500); v"a.%"oN8  
breakWhile = true; `T;Y%
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for(int i=0;i<nStartPos.length;i++) v\?J$Hdd  
{ Ffp<|2T2_  
if(!fileSplitterFetch.bDownOver) MW6
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{ fKZgAISF  
breakWhile = false; <E.$4/T  
break; {Lm%zdk*k  
} y?s8UEC  
} Nt#a_  
if(breakWhile) lKF<]25  
break; o{&UT VyGs  
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//count++; \4e6\6 +  
//if(count>4) HfgK0wIi  
// siteStop(); Bpw<{U  
} ,"W.A  
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System.err.println("文件下载结束！"); !HP/`R  
} ~NtAr1  
catch(Exception e){e.printStackTrace ();} Y2,\WKa  
} $"&U%3  
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//获得文件长度 f:-dw6a=s  
public long getFileSize() Ew kZzVuX  
{ t846:Z%[  
int nFileLength = -1; a:3f>0_t  
try{ ;c_pa0L  
URL url = new URL(siteInfoBean.getSSiteURL()); w+0Ch1$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /o_h'l|PS  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5{&<X.jv  
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int responseCode=httpConnection.getResponseCode(); ?~5J!|r#  
if(responseCode>=400) Xqac$%[3  
{ S(f V ,;Z  
processErrorCode(responseCode); 8?7gyp!k_f  
return -2; //-2 represent access is error :>t?^r(  
} ]'/ZSy,  
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String sHeader; @Sl
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for(int i=1;;i++) -^JGa{9*  
{ *I}_
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D@ji1$K  
//Utility.log(in.readLine()); iY2%_b!5  
sHeader=httpConnection.getHeaderFieldKey(i); z4nVsgQ$  
if(sHeader!=null) RO"*&o'K'  
{ y=jTS  
if(sHeader.equals("Content-Length")) a;A&>Ei}  
{ oEWx9c{~$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2
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break; '\2lWR]ndd  
} Z)U#5|sf  
} ;')T}wuq  
else 0CD2o\`8  
break; 'd"\h#  
} X&<#3n  
} -^(NIl'  
catch(IOException e){e.printStackTrace ();} L^`oJ9k!  
catch(Exception e){e.printStackTrace ();} M]>JI'8  
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Utility.log(nFileLength); e<p_u)m  
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return nFileLength; [\ JZpF  
} A/U tf0{3"  
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//保存下载信息（文件指针位置） $Q:5KNF+p  
private void write_nPos() 7<=7RPWmD  
{ i#jCf3%+ h  
try{ ^saJfr
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output = new DataOutputStream(new FileOutputStream(tmpFile)); m,u? ^W  
output.writeInt(nStartPos.length); >oc7=F<8lS  
for(int i=0;i<nStartPos.length;i++) R$cO`L*s  
{ Pc]c8~  
// output.writeLong(nPos); Kg@9kJB  
output.writeLong(fileSplitterFetch.nStartPos);
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output.writeLong(fileSplitterFetch.nEndPos); ;e0>.7m  
} +{/zP{jH  
output.close(); 'Ph4(Yg  
} K@{jY\AZNx  
catch(IOException e){e.printStackTrace ();} !UUh7'W4u  
catch(Exception e){e.printStackTrace ();} T T0O %  
} I
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//读取保存的下载信息（文件指针位置） 0nAeeVz|  
private void read_nPos() 2|~&x~  
{ 5b B[o6+  
try{ r/Pg,si  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); yh5KN_W  
int nCount = input.readInt(); nWZrB s _  
nStartPos = new long[nCount]; ,ASY &J5)7  
nEndPos = new long[nCount]; !00%z  
for(int i=0;i<nStartPos.length;i++) AmSJ!mTd8o  
{ :B- ,*@EU  
nStartPos = input.readLong(); Qb# S)[6s+  
nEndPos = input.readLong(); >[xQUf,p  
} c2"eq2'BS  
input.close(); xDr *|d  
} `T9
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catch(IOException e){e.printStackTrace ();} xs &vgel>  
catch(Exception e){e.printStackTrace ();} oS_p/$F,  
} 72-@!Z0e  
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private void processErrorCode(int nErrorCode) <{-DYRiN  
{ g1J]z<&  
System.err.println("Error Code : " + nErrorCode); 1<R \V  
} ^ O`  
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//停止文件下载 *
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public void siteStop() \O/=g6w|t}  
{ +vbNZqwz  
bStop = true; HRw,D=  
for(int i=0;i<nStartPos.length;i++) Ta[}k/zW  
fileSplitterFetch.splitterStop(); z
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} v^E5'M[A  
} lp]O8^][&  
//负责部分文件的抓取 OIWo* %  
**FileSplitterFetch.java c&_3"2:  
*/ LQQhn{[D  
package NetFox; {jq-d
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import java.io.*; eeX)JC0A  
import java.net.*; #e0+;kBh  
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public class FileSplitterFetch extends Thread { <=`@`rm{  
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String sURL; //File URL ><DE1tG  
long nStartPos; //File Snippet Start Position a[JgR/E@x  
long nEndPos; //File Snippet End Position v]1rH$  
int nThreadID; //Thread's ID 6RtpB\hq  
boolean bDownOver = false; //Downing is over '\;tmD"N5#  
boolean bStop = false; //Stop identical 9(I4x]`  
FileAccessI fileAccessI = null; //File Access interface [gE2lfaEy  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %$}iM<  
{ qy]-YJ
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this.sURL = sURL; b13>>'BMB  
this.nStartPos = nStart; #*`|}_6L  
this.nEndPos = nEnd; 8_LDS  
nThreadID = id; r#j*vO '  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &vn9l#
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} cP Y^Bf5)  
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public void run() ["7}u^z@<+  
{ 93rE5eGs  
while(nStartPos < nEndPos && !bStop) 8;5/_BwMu  
{ {F4:  
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try{ ~+g5?y  
URL url = new URL(sURL); 5
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M1i|qjb:l  
httpConnection.setRequestProperty("User-Agent","NetFox"); Psv!`K  
String sProperty = "bytes="+nStartPos+"-"; xWMMHIu  
httpConnection.setRequestProperty("RANGE",sProperty); kDKpuA!  
Utility.log(sProperty); *SW,pHYnLb  
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InputStream input = httpConnection.getInputStream(); t>[r88v  
//logResponseHead(httpConnection); Em7q@  
8?$2;uGL  
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byte[] b = new byte[1024]; MoA{ /{  
int nRead; g,;MV7yE  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) JB|I/\(A  
{ B?M+`;  
nStartPos += fileAccessI.write(b,0,nRead); y/FisX  
//if(nThreadID == 1) )v9[/ ]*P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BAhC-;B#R  
} x0d+cSw  
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Utility.log("Thread " + nThreadID + " is over!"); YJy*OS_&  
bDownOver = true; HT&0i,`  
//nPos = fileAccessI.write (b,0,nRead); zxh"@j$?  
} = `^jz}  
catch(Exception e){e.printStackTrace ();} jmFN*VIL  
} ,jn?s^X6Dj  
} 6~}H
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//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) |}`5<a!6U  
{ >W;i2%T  
for(int i=1;;i++) I%p#E#[G  
{ qj1z>,\  
String header=con.getHeaderFieldKey(i); T)uw2  
if(header!=null) ]ok>PH]  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); c;^J!e  
else ^Toi_  
break; "|.(yN  
} Bag#An1  
} C gx?K]>y  
- -G1
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public void splitterStop() _a&|,ajy>  
{ nR7\ o(!  
bStop = true; e0L;V@R  
} ,:`6x[ +  
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} _#C}hwOR>X  
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/* HhL%iy1  
**FileAccess.java 0U>Q<I}  
*//文件访问(定位，写) V%ch'  
package NetFox; =lwS\mNs  
import java.io.*; GHy#D]Z  
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public class FileAccessI implements Serializable{ +a/o
)C{  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -e~Uu  
RandomAccessFile oSavedFile; 7mM;Q  
long nPos; O[!o1.  
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public FileAccessI() throws IOException ]D%k)<YK  
{ N-gRfra+8L  
this("",0); 6<Z:Xw  
} [fp"MPP3  
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public FileAccessI(String sName,long nPos) throws IOException 9#<Og>t2y  
{ 5-^%\?,x  
oSavedFile = new RandomAccessFile(sName,"rw"); ~8*oGG~s  
this.nPos = nPos; YJ$ewK4E#.  
oSavedFile.seek(nPos); B5:g{,C  
} er0D5f R  
yf)`jPM1<  
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public synchronized int write(byte[] b,int nStart,int nLen) 0>
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{ 3J T3;O  
int n = -1; KeB4Pae|V  
try{ 4MJzx9#  
oSavedFile.write(b,nStart,nLen); (x qA.(F  
n = nLen; |lxy< C4V  
} |a{]P=<q  
catch(IOException e)
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{ |L;psK  
e.printStackTrace (); xV#a(>-4  
} H
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rf->mk{  
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return n; ;YDF*~9u  
} hy
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} LUck>l\l  
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/* oDP((I2-  
**SiteInfoBean.java </gp3WQ.  
*/ AwUc{h l<  
package NetFox; J4"swPf  
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public class SiteInfoBean { 
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private String sSiteURL; //Site's URL VONAw3k7!  
private String sFilePath; //Saved File's Path P0e""9JOo  
private String sFileName; //Saved File's Name vt@Us\fI  
private int nSplitter; //Count of Splited Downloading File `t0f L\T  
j yRSEk$  
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public SiteInfoBean() -'[(Uzj  
{//nSplitter的缺省值为5 Wi[m`#  
//default value of nSplitter is 5 -I-Uh{)j  
this("","","",5); *3O>J"  
} zN+*R;Ds  
#we>75l{+R  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]<T8ZA_Y;  
{ HI\f>U  
sSiteURL= sURL; +}QBzGW`  
sFilePath = sPath; $[iT~B$  
sFileName = sName; IT`=\K/[4  
this.nSplitter = nSpiltter; kt{C7qpD  
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} Hp
}  
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public String getSSiteURL() i9eyrl+!  
{ ZBmXaP[9  
return sSiteURL; #RM3^]h  
} F|l`YtZZd  
=6L*!JP<  
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public void setSSiteURL(String value) wD],{y  
{ nS+FX&_  
sSiteURL = value; *Z`XG_s5  
} eKVALUw  
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public String getSFilePath() dA1 C)gLi  
{ dHG Io  
return sFilePath; 8b:clvh  
} 
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public void setSFilePath(String value) ZSPgci  
{ W 9Vz[  
sFilePath = value; *el(+ib%  
} yYToiW *  
n<?SZ^X{,/  
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public String getSFileName() 5BHOHw D{  
{ dGsS<@G  
return sFileName; 3G%wZ,)C  
} |'c4er/;#  
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public void setSFileName(String value) :YqQlr\
 
{ 6!+X.+  
sFileName = value; ^+*GbY$'  
} U.RW4df%E  
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\ I^nx+l  
public int getNSplitter() W""*hJ  
{ O[IR|  
return nSplitter; l*K I  
} O xT}I  

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public void setNSplitter(int nCount) xN`r4  
{ aGB0-;.t7  
nSplitter = nCount; JFRpsv  
} m']9Q3-  
} EWb(uWC8h  
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/* 4jX@m  
**Utility.java &@YFje6Lcm  
*/ n .f4z<  
package NetFox; B;z;vrrL  
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public class Utility { _BG8/"h32  
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public Utility() -ca7x`yo  
{ s, n^  
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} |}K  
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//线程睡眠 K,f* SXM  
public static void sleep(int nSecond) \G$QNUU  
{ @[MO,J&h  
try{ kSB  
Thread.sleep(nSecond); VK2@2`$  
} :`0'GM" `  
catch(Exception e) l`@0zw+  
{ #V.ZdLo(  
e.printStackTrace ();
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} [ rQMD^:M$  
} }#yU'#|d  
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//日志 m`hGDp3  
public static void log(String sMsg) -$+,]t^GV  
{ j4;Du>obQ  
System.err.println(sMsg); i@P9EU  
} <7=&DpjI7F  
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public static void log(int sMsg) zlH28V  
{ h&lyxYZ+T$  
System.err.println(sMsg); X<(6T  
} sYGR-:K  
} HSNOL  
m6b$Xyq[  
gUl1CH&  
/* f:]u`ziM  
**TestMethod.java WgE@89  
*/ NW z9C=y  
package NetFox; L-#e?Y}$J
 
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D=$4/D:;  
public class TestMethod { }@d>,1DU  
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public TestMethod() }FrEF\}]_7  
{ ///xx/weblogic60b2_win.exe '%R<"  
try{ ~gP7s_qr{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -*?p F_*w  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); R"@7m!IA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M~uMY+>   
fileFetch.start(); tKwn~T  
} J*5hf:?i  
catch(Exception e){e.printStackTrace ();} 14mf}"z\  
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} dUIqDl  
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public static void main(String[] args) >-b&v$  
{ *-0>3  
new TestMethod(); jh[ #p?:  
} 4Rx~s7l  
} 6Lb{r4^  
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