http断点续传简单实现（java)

/* RH'F<!p  
**SiteFileFetch.java a+a%}76N  
*/ >A'!T'"~  
package NetFox; GLKN<2|2@y  
import java.io.*; |C2.Zay  
import java.net.*; EPd.atA  
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public class SiteFileFetch extends Thread { A_q3p\b  
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SiteInfoBean siteInfoBean = null; //文件信息Bean TcKKI  
long[] nStartPos; //开始位置 7E6?)bgh  
long[] nEndPos; //结束位置 2,e|,N"zN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |xgCV@  
long nFileLength; //文件长度 8^"|-~
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boolean bFirst = true; //是否第一次取文件 j&G~;(DY  
boolean bStop = false; //停止标志 )J6b:W  
File tmpFile; //文件下载的临时信息 fi4/@tV?$L  
DataOutputStream output; //输出到文件的输出流 %/4_|@<'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） T#^6u)  
public SiteFileFetch(SiteInfoBean bean) throws IOException "KTnX#<0  
{ {FmFu$z+[  
siteInfoBean = bean; u/:Sf*;?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "vRqtEBO@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gMK3o8B/  
if(tmpFile.exists ()) #/v_h6$  
{ Tx?@*Q  
bFirst = false;
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read_nPos(); 4!s k3Cw{  
}
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else
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{ o-CJdOS  
nStartPos = new long[bean.getNSplitter()]; ZG[0rvW  
nEndPos = new long[bean.getNSplitter()]; 'nDT.i  
} |2&mvjk@H  
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} 2?nyPqT3AM  
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! tP
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public void run() ZXDMbMD  
{ COL8YY  
//获得文件长度 [^=8k2  
//分割文件 `IRT w"  
//实例FileSplitterFetch R]sjG
<  
//启动FileSplitterFetch线程 m1; <T@  
//等待子线程返回 k
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try{ v;qL?_:=c  
if(bFirst) VM|)\?Q  
{ .MPOUo/e  
nFileLength = getFileSize(); O xau
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if(nFileLength == -1) 4wD^?S!p  
{ Q)X\VQcgj  
System.err.println("File Length is not known!"); &J@ZF<Ib  
} y
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else if(nFileLength == -2) CKt~#$ I%  
{ h?tV>x/Fu  
System.err.println("File is not access!"); VzM@DM]=~  
} vgZPDf|  
else ghQsS|)p.  
{ M6Z`Pwv];  
for(int i=0;i<nStartPos.length;i++)  !3M!p&  
{ 95&sFT C  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J 2~B<=V  
} l+X^x%EA  
for(int i=0;i<nEndPos.length-1;i++) Sh6 NgO  
{ a#GqJ?nY  
nEndPos = nStartPos[i+1]; (xJBN?NRO  
} "MP{z~Mmj  
nEndPos[nEndPos.length-1] = nFileLength; !m5\w>  
} `CouP-g.  
} 9>, \QrrH  
*<5lx[:4/x  
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//启动子线程 #{`NJ2DU]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ec/+9H6g  
for(int i=0;i<nStartPos.length;i++) BU\NBvX$  
{  cJ{P,K  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xx#Ef@bS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9.}3RAB(cv  
nStartPos,nEndPos,i); <sG>[\i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =n?@My?;  
fileSplitterFetch.start(); H t$%)j9  
} o|.me G  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b|'LtL$Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *hgsS~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n{* [Y  
nEndPos = " + nFileLength); g@i 4H[k  
// fileSplitterFetch[nPos.length-1].start(); 1:V/['|*g)  
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//等待子线程结束 5S?Xl|8E  
//int count = 0; Ek\Zi#f<  
//是否结束while循环 w5R9\<3L  
boolean breakWhile = false; Y
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while(!bStop) Ok"wec+,  
{ 9uo\&,,  
write_nPos(); 7En~~J3  
Utility.sleep(500); ]qQB+]WN  
breakWhile = true; Fd0FG A&L  
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for(int i=0;i<nStartPos.length;i++) ~$Yuxo  
{ p`C5jfI  
if(!fileSplitterFetch.bDownOver) 05DtU!3O  
{ ]sIFK  
breakWhile = false; ]z@]Fi33Y  
break; R|yTUGY  
} HM x9M$  
} _J`M>W)8  
if(breakWhile) '7%9Sqx  
break; ?q7Gs)B=^'  
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//count++; s@9#hjv2  
//if(count>4) ON^u|*kO  
// siteStop(); g:V6B/M&  
} ;0W
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System.err.println("文件下载结束！"); Z.:A26  
} WV5R$IqY  
catch(Exception e){e.printStackTrace ();} HKf3eC  
} ? -tw*2+  
{K}+$jzGVt  
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//获得文件长度 Ds$;{wl#x  
public long getFileSize() F U%b"gP^  
{ 6 >2! kM7  
int nFileLength = -1; R 1\]Y  
try{ }'JPA&h|  
URL url = new URL(siteInfoBean.getSSiteURL()); !h;VdCCi#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =!2  
httpConnection.setRequestProperty("User-Agent","NetFox"); e<pojb1Q  
5 [*jfOz  
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int responseCode=httpConnection.getResponseCode(); n+w>Qz'  
if(responseCode>=400) @B <_h+  
{ WbF\=;$=7  
processErrorCode(responseCode); Ro69woU  
return -2; //-2 represent access is error -R]S)Odml  
} "^%Il  
2^:nlM{u  
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String sHeader; P^r8JhDJ  
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for(int i=1;;i++) 37DvI&  
{ (nG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Si(?+bda0c  
//Utility.log(in.readLine()); }r[BME  
sHeader=httpConnection.getHeaderFieldKey(i); [\y>Gv%  
if(sHeader!=null) jLU)S)  
{ SX.v5plhc  
if(sHeader.equals("Content-Length")) XPSWAp)  
{  G%{jU'2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); fzcT(y  
break; bzTM{<]sv  
} G"(!5+DLy  
} ~5zhK:7c  
else 4H)a7<,  
break; W\.(~-(So  
} }#@LZ)]hK  
} j@f(cRAf#  
catch(IOException e){e.printStackTrace ();} #:X:~T  
catch(Exception e){e.printStackTrace ();} <U";V)  
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Utility.log(nFileLength); x4(WvQ%O#  
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return nFileLength; iW)Ou?aS  
} .T2I]d  
\hVFK6  
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//保存下载信息（文件指针位置） ;
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private void write_nPos() s5 BV8 M  
{ ~PH
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try{ c'C2V9t  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NoT oLt\  
output.writeInt(nStartPos.length); lH8?IkK,g  
for(int i=0;i<nStartPos.length;i++) CS  
{ *^]ba>  
// output.writeLong(nPos); #=2~MXa@z7  
output.writeLong(fileSplitterFetch.nStartPos); 5;+Bl@zGu  
output.writeLong(fileSplitterFetch.nEndPos); x[E`2_Ff0  
} U8z,N1]r*`  
output.close(); YZd4% zF  
} x1Uj4*Au  
catch(IOException e){e.printStackTrace ();} Zv_<*uzKZ  
catch(Exception e){e.printStackTrace ();} x$t=6@<
]  
} 8w4.|h5FP  
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//读取保存的下载信息（文件指针位置） bk|>a=o3  
private void read_nPos() I[/u5V_b'  
{ H Zc;.jJ  
try{ iD9GAe}x  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kE1u-EA  
int nCount = input.readInt(); R~o?X^^O  
nStartPos = new long[nCount]; qohUxtnTK>  
nEndPos = new long[nCount]; U3>G9g>^B  
for(int i=0;i<nStartPos.length;i++) pAYuOk9n  
{ (Qnn  
nStartPos = input.readLong(); &7cy9Z~m  
nEndPos = input.readLong(); z]pH'c39
 
} qQQ~[JL  
input.close(); mOBS[M5*  
} 59|Tmf(dS;  
catch(IOException e){e.printStackTrace ();} MZ.Jk
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catch(Exception e){e.printStackTrace ();} A-kI_&g\Og  
} +Z+]Tqo  
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private void processErrorCode(int nErrorCode) :(Gg]Z9^8  
{ QAr1U7{(.  
System.err.println("Error Code : " + nErrorCode); SExd-=G  
} F C"dQ  
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&( Z8G~h4  
//停止文件下载 |o`TRqs  
public void siteStop() P+
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{ My)/d]a  
bStop = true; Z^b1i`v  
for(int i=0;i<nStartPos.length;i++) R lv|DED$  
fileSplitterFetch.splitterStop(); S;= D/)[mr  
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} 7@:uVowQ  
} 0I,-1o|s  
//负责部分文件的抓取 8ARpjYZP  
**FileSplitterFetch.java Q~`n%uYg\{  
*/ Oo,<zS=ICk  
package NetFox; Pp?J5HW  
,JR7N_"I  
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import java.io.*; 2`x[y?Tn  
import java.net.*; TB9ukLG^<<  
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public class FileSplitterFetch extends Thread { ?>e-6*.  
%@LVoP!@!  
,oR}0(^"\<  
String sURL; //File URL qT(j%F  
long nStartPos; //File Snippet Start Position .Sm7na K  
long nEndPos; //File Snippet End Position SJL?(S*  
int nThreadID; //Thread's ID 3ILEc:<
0J  
boolean bDownOver = false; //Downing is over B?k75G  
boolean bStop = false; //Stop identical 1^vN?#Kt  
FileAccessI fileAccessI = null; //File Access interface Rgg(rF=K6  
74>.E^/x  
 'y1=Z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f>dWl$/_s  
{ 7JjTm^bu  
this.sURL = sURL; mIt=r_
  
this.nStartPos = nStart; YOqBIbp~&)  
this.nEndPos = nEnd; !-[e$?-  
nThreadID = id; Rb?6N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8^2Q ~{i  
} wPOQy~:  
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8|gwH2st~  
public void run() @hp@*$#& 9  
{ E`BL3+kQ  
while(nStartPos < nEndPos && !bStop) ka655O/)&  
{ #49,7OBU  
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try{ Que-  
URL url = new URL(sURL); S'q (Qo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0I1bY]*  
httpConnection.setRequestProperty("User-Agent","NetFox"); E`$d!7O  
String sProperty = "bytes="+nStartPos+"-"; =98@MX%P  
httpConnection.setRequestProperty("RANGE",sProperty); [+UF]m%W  
Utility.log(sProperty); |-bAzt  
?FJU>+{">  
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InputStream input = httpConnection.getInputStream(); =5is
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//logResponseHead(httpConnection); 3x=T&X+  
!gu# #MrJ9  
}<m9w\pA  
byte[] b = new byte[1024]; w\!aKeP'  
int nRead; cE'MSB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) pwr,rAJ}$j  
{ v="i0lL_  
nStartPos += fileAccessI.write(b,0,nRead); O1Vs!  
//if(nThreadID == 1) s"s^rC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,5.ve)/dE  
} `*^ f =y  
r$d,ChzQn?  
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Utility.log("Thread " + nThreadID + " is over!"); [5yLg  
bDownOver = true; w,n&K6<  
//nPos = fileAccessI.write (b,0,nRead); edD19A  
} bkTk:-L5:  
catch(Exception e){e.printStackTrace ();} [7oU =  
} {HHc}8  
} jt=%oa  
\b6H4aQii  
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//打印回应的头信息 <'f+nC=2  
public void logResponseHead(HttpURLConnection con) UU~S{!*+L  
{ ^z>3+oi  
for(int i=1;;i++) DAa??/,x7  
{ (hr*.NS#  
String header=con.getHeaderFieldKey(i); Fu].%`*xJ  
if(header!=null) ):-\TVz~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0
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Utility.log(header+" : "+con.getHeaderField(header)); R<}UT  
else x%@n$4wk7  
break; u 6A!Sw  
} j\@Ht~G  
} ,ELbm  
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public void splitterStop() O1[`2kj^HB  
{ ;hzm&My  
bStop = true; M<$a OW0  
} hhRUC&Y%V  
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} ;d5d$Np@m&  
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/* l7vU{Fd-h^  
**FileAccess.java X!6oviT|m  
*//文件访问(定位，写) ,X^I]]  
package NetFox; xYSNop3_  
import java.io.*; _=$:<wIE[  
.Aj4?AXWc  
rs`"Kz`(  
public class FileAccessI implements Serializable{ O7,)#{  
&-.NkW@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HX}9;O  
RandomAccessFile oSavedFile; f i#p('8  
long nPos; @
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public FileAccessI() throws IOException M4rI]^lJ  
{ 5=@q!8a*  
this("",0); K%i9S;~  
} `YL)[t? V  
!I)wI~XF)5  
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public FileAccessI(String sName,long nPos) throws IOException {zhajY7  
{ r" 4u)H>  
oSavedFile = new RandomAccessFile(sName,"rw"); *M^(A}+O  
this.nPos = nPos; ?azi(ja  
oSavedFile.seek(nPos); `!- w^~c  
} V\|V1c  
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 {@E(p4W  
public synchronized int write(byte[] b,int nStart,int nLen) S~GL_#a  
{ <e)u8+(  
int n = -1; 7:Cq[u fl  
try{ Le,e,#hiY  
oSavedFile.write(b,nStart,nLen); 6Z,GD  
n = nLen; ?R#?=<VkG  
} ^p7g[E&  
catch(IOException e) VelR8tjP  
{ ai
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e.printStackTrace (); crvq]J5  
} <?h,;]U  
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return n; A*x3O%zH  
} v#Xl  
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} vXI2u;=y  
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/* iCXKi7  
**SiteInfoBean.java RvXK?mL4F  
*/ :n0czO6E  
package NetFox; ?j:U<TY)  
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public class SiteInfoBean { !TwH;#U w  
|K(jXZ)  
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private String sSiteURL; //Site's URL -h%!#g  
private String sFilePath; //Saved File's Path :@oy5zib  
private String sFileName; //Saved File's Name e09('SON(  
private int nSplitter; //Count of Splited Downloading File 
F
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public SiteInfoBean() 0pW?v:!H  
{//nSplitter的缺省值为5 VC T~"T2R  
//default value of nSplitter is 5 }eLnTi{  
this("","","",5); +!6dsnr8  
} q'9}Hz  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \g;o9}@3~  
{ 2N/4.  
sSiteURL= sURL; 5,~Ju>y*  
sFilePath = sPath; {];8jdg/?  
sFileName = sName; r5wy]z^  
this.nSplitter = nSpiltter; vQ_D%f4;  
Y(U+s\X  
;;{!wA+"D  
} 0D.qc8/V4.  
l!7O2Ai5  
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public String getSSiteURL() 3*<?'O7I0  
{ 5vSJjhS  
return sSiteURL; |%HTBF  
} aM6qYO!jA  
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rdBF+YN9/?  
public void setSSiteURL(String value) h8zl\  
{ [$iKx6\  
sSiteURL = value; "tX=^4
 
} BXj]]S2  
{37v.4d;  
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public String getSFilePath() @o/126(k  
{ L0QF(:F5  
return sFilePath; [+8in\T i  
} r!C#PiT}I  
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r  
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public void setSFilePath(String value) 2Y-NxW^]  
{ d) i64"  
sFilePath = value; }bA@QEJ  
} %j4AX  
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public String getSFileName() _Yqog/sG  
{ SSH 1Ge5|  
return sFileName; sngM4ikhs  
} Bkaupvv9S  
]Te,m}E  
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public void setSFileName(String value) PN"s^]4  
{ nP5T*-~  
sFileName = value; Jb1L[sT2  
} h,!`2_&UQ  
Hsl0|jy(/  
/$Ca}>  
public int getNSplitter() e]Q bC"  
{ ?y`we6~\1  
return nSplitter; S?BI)shmg  
} KP*cb6vA  
+J;T= p  
j8[RDiJ
  
public void setNSplitter(int nCount) 4apy{W  
{ Yn+d!w<3:  
nSplitter = nCount; /t
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} 5S/YVRXq  
} ~A-Y%P  
yR'%UpaE  
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/* !=SBeq  
**Utility.java *+rWn*L  
*/ DV5K)m&G  
package NetFox; +ebmve \+  
appWq}db  
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public class Utility { j.:I{!R#  
yc:y}"  
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public Utility() F!*tE&Se+  
{ -RKqbfmi=  
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} G W@g  
4Uzx2   
//线程睡眠 2,
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public static void sleep(int nSecond) UV
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{ =+ vl+h  
try{ v
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Thread.sleep(nSecond); @Lk!nP  
} SpJIEw  
catch(Exception e) hztxsvw  
{ jn,_Ncd#  
e.printStackTrace (); 7%)KB4(\_
 
} BH3%dh:9  
} ;'i>^zX`  
<yg!D21Y  
//日志 B$D7}=|kc  
public static void log(String sMsg) 8lZB3p]X  
{ T6^H%;G  
System.err.println(sMsg); "fN=Y$G  
} qS?uMms7w  
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/k
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public static void log(int sMsg) e?yrx6  
{ LE]mguvs  
System.err.println(sMsg); Sece#K2J|  
} HY>zgf,0  
} ?Jy/]j5fI  
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,.,spoV  
/* 4qvE2W}&  
**TestMethod.java ZgI?#e  
*/ efXiZ  
package NetFox; #BhDC.CcW  
`:#IZ  
lNbAt4]}f(  
public class TestMethod { \\9I:-j:p  
/^rJ`M[;  
#Mm1yXNu  
public TestMethod() /#-zI#iK  
{ ///xx/weblogic60b2_win.exe pz0Q@n/X  
try{ UB2Ft=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^SvGSxi  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }O+`X) 9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5v_vv'~  
fileFetch.start(); 0i4XS*vPv  
} F|bg2)|du8  
catch(Exception e){e.printStackTrace ();} .g?Ppma  
~v|NC([(  
-I'Jm=q3]  
} )l6(ss!J  
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35 d:r:  
public static void main(String[] args) ArVW2gL  
{  uWDWf5@  
new TestMethod(); 4`zK`bRcK#  
} 5iZx -M  
} hn[
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