http断点续传简单实现（java)

/* M];?W  
**SiteFileFetch.java `p'(:W3a  
*/ tW8&:L,m  
package NetFox; W[R^5{k`  
import java.io.*; 6 o
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import java.net.*; ' ~F  
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public class SiteFileFetch extends Thread { )[]*Y]vSx  
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SiteInfoBean siteInfoBean = null; //文件信息Bean vTk\6o q  
long[] nStartPos; //开始位置 2x<A7l)6  
long[] nEndPos; //结束位置 937 z*mh  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <|kS`y  
long nFileLength; //文件长度 7%0V?+]P  
boolean bFirst = true; //是否第一次取文件 |l#<vw wE  
boolean bStop = false; //停止标志 |({ M8!BS  
File tmpFile; //文件下载的临时信息 &%\H170S  
DataOutputStream output; //输出到文件的输出流 )/vse5EG+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） er44s^$  
public SiteFileFetch(SiteInfoBean bean) throws IOException cOz/zD f5  
{ !VoAN5#;  
siteInfoBean = bean; R2`-*PZ_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); EG&97lb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )/{zTg8$?/  
if(tmpFile.exists ()) =U- w!uW  
{ zcrM3`Zh  
bFirst = false; #JD:i%  
read_nPos(); Q/2(qD; u  
} 5nA *'($j  
else "pa2,-&  
{ \}p!S$`  
nStartPos = new long[bean.getNSplitter()]; 1I#]OY#>  
nEndPos = new long[bean.getNSplitter()]; 0g{`Qd  
} j YVR"D;  
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} m.g2>r`NU  
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public void run() ,ej89  
{  d H ;  
//获得文件长度 xRp;y*  
//分割文件 "R5! VV  
//实例FileSplitterFetch >K@Y8J+e#  
//启动FileSplitterFetch线程 .gP}/dj  
//等待子线程返回 ;+3XDz v  
try{ U
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if(bFirst) T4fVZd)x  
{ 9V0@!M8S  
nFileLength = getFileSize(); H(rK39Q  
if(nFileLength == -1) 3X>x`
  
{ ->S# `"@$  
System.err.println("File Length is not known!"); ,"xr^@W
 
} V\
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else if(nFileLength == -2) ; VH:dg  
{ CEXD0+\q  
System.err.println("File is not access!"); ar[I| Q_  
} =g3o@WD/G  
else Z.$)#vM5  
{ vLT$oiN[c  
for(int i=0;i<nStartPos.length;i++) kwAL]kI  
{ |J^}BXW'^)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wOLA8UYW  
} H)rE-7(f!  
for(int i=0;i<nEndPos.length-1;i++) 9,J^tN@^  
{ /y-eVu6  
nEndPos = nStartPos[i+1]; fP>~ @^  
} SF.Is=b  
nEndPos[nEndPos.length-1] = nFileLength; vP@\"  
} RqU^Q*/sF
 
} ?igA+(.  
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//启动子线程 g)`;m%DG6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; T?e(m  
for(int i=0;i<nStartPos.length;i++) NfsF'v  
{ ?qt.+2:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {^V9?^?d (  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C &~s<tcn  
nStartPos,nEndPos,i); hYSzr-)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Pu0 <Clh  
fileSplitterFetch.start(); ~zO>Q4-k  
} 3IyNnm=u  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0Bn35.K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0=erf62=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 
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nEndPos = " + nFileLength); ggL^*MV  
// fileSplitterFetch[nPos.length-1].start(); s,|"s|P  
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//等待子线程结束 A9;!\Wo  
//int count = 0; r>,s-T!7  
//是否结束while循环 {7Qj+e^  
boolean breakWhile = false; Y9r##r+  
- U Elu4n&  
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while(!bStop) X"EZpJ'W  
{ g/(3D  
write_nPos(); q445$ndCT  
Utility.sleep(500); Z!foD^&R  
breakWhile = true; -PiakX  
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for(int i=0;i<nStartPos.length;i++) p6AF16*f0  
{ i}
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if(!fileSplitterFetch.bDownOver) 7wz9x8\t  
{ S3N+9*iK  
breakWhile = false; E]c0+rh~  
break; }l<:^lX  
} FByA
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}  \<u  
if(breakWhile) xtFGj,N  
break; a\ZNNk  
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//count++; 8s9ZY4_  
//if(count>4) |7)oX  
// siteStop(); ;km^ OO$  
} q(\kCUy!  
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System.err.println("文件下载结束！"); $i|d=D&t  
} wzf  
catch(Exception e){e.printStackTrace ();} CNl @8&R  
} wBI>H 7A  
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//获得文件长度 6mmc{kw'  
public long getFileSize() pg.BOz\'q  
{ K};~A?ET,h  
int nFileLength = -1; HB*H%>L{"B  
try{ t_kRYdW9  
URL url = new URL(siteInfoBean.getSSiteURL()); MG:eI?G/'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sH51 .JG  
httpConnection.setRequestProperty("User-Agent","NetFox"); |crm{]7X  
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int responseCode=httpConnection.getResponseCode(); {NUI8AL46A  
if(responseCode>=400) ksy]t|  
{ U28frRa  
processErrorCode(responseCode); "_ H9]}Q  
return -2; //-2 represent access is error T!X`"rI  
} 9?tG?b0  
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String sHeader; 821;;]H  
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for(int i=1;;i++) ST1c`0e  
{ 8}K4M(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LV@tt&|N  
//Utility.log(in.readLine()); x4XCR,-  
sHeader=httpConnection.getHeaderFieldKey(i); jidRh}>a=  
if(sHeader!=null) ![&9\aH  
{ KnC:hus  
if(sHeader.equals("Content-Length")) F$@(0c  
{ Eg(.L,dj  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6PT"9vR`)  
break; Pos(`ys;  
} Zg$RiQ^-{J  
}
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else ~oz??SX  
break; x7!gmbMfK'  
} 6,~]2H'zq  
} y' RQ_Gi  
catch(IOException e){e.printStackTrace ();} 3(`P x}  
catch(Exception e){e.printStackTrace ();} 5;X r0f  
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Utility.log(nFileLength); d}
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return nFileLength; .l$U:d  
} 5Z`f.}^w  
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//保存下载信息（文件指针位置） Y+{jG(rg.F  
private void write_nPos() q!{>Nlk  
{ nd }Z[)  
try{ Sym}#F\s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ;tC$O~X  
output.writeInt(nStartPos.length); .'b|pd  
for(int i=0;i<nStartPos.length;i++) ZF@$3   
{ Muyi
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// output.writeLong(nPos); r@EHn[w  
output.writeLong(fileSplitterFetch.nStartPos); m(`O>zS  
output.writeLong(fileSplitterFetch.nEndPos); #^{%jlmHxJ  
} w+$~ds  
output.close(); z"-oD*ICw  
} S$ k=70H  
catch(IOException e){e.printStackTrace ();} 9Dp0Pi?29  
catch(Exception e){e.printStackTrace ();} Z1_F)5
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} 0:JNkXZ:  
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//读取保存的下载信息（文件指针位置） n`V?n  
private void read_nPos() [I}z\3Z %  
{ CSY-{  
try{ -us:!p1T  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); V''fmWo7  
int nCount = input.readInt(); k
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nStartPos = new long[nCount]; ,(&Fb~r]  
nEndPos = new long[nCount]; Zv(6VVj  
for(int i=0;i<nStartPos.length;i++) GT\yjrCd  
{ A0OA7m:~4  
nStartPos = input.readLong(); /vC!__K9:  
nEndPos = input.readLong(); m\70&%v  
} L1f=90  
input.close(); - ,?LS w  
} ~n!&~  
catch(IOException e){e.printStackTrace ();} 8Ltl32JSB[  
catch(Exception e){e.printStackTrace ();} USaa#s4'  
} tu(^D23  
q[9N4nj$<  
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private void processErrorCode(int nErrorCode) m6#a{  
{ 'Va<GHr>+  
System.err.println("Error Code : " + nErrorCode); .PV(MV  
} J*38GX+  
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//停止文件下载 8nWPt!U:  
public void siteStop() 5nTcd
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{ !a25
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bStop = true; *Ms&WYN-  
for(int i=0;i<nStartPos.length;i++) I;n<) >  
fileSplitterFetch.splitterStop(); O<#8R\v  
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} :dNJ2&kJ  
} Gpi_p  
//负责部分文件的抓取 ,Xr`tQ<@  
**FileSplitterFetch.java q
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*/ __zHe-.m  
package NetFox; 9C=*>I27?  
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/DP0K @%  
import java.io.*; 8_o~0lb  
import java.net.*; |5ge4,}0  
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public class FileSplitterFetch extends Thread { c&,q`_t  
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String sURL; //File URL tCm]1ZgRW  
long nStartPos; //File Snippet Start Position f/s"2r  
long nEndPos; //File Snippet End Position 9|[uie  
int nThreadID; //Thread's ID bub6{MQW8e  
boolean bDownOver = false; //Downing is over _!!Fg%a5"R  
boolean bStop = false; //Stop identical 9_?e, Q  
FileAccessI fileAccessI = null; //File Access interface O&&_)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z`86YYGK  
{ HVhP |+  
this.sURL = sURL; ?>iU
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this.nStartPos = nStart; /h{Rf,H  
this.nEndPos = nEnd; U=7nz|  
nThreadID = id; dsj}GgG?Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0TSB<,9a[  
} ]T)<@bmL  
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public void run() Iqn (NOq^[  
{ 7!h> < sx  
while(nStartPos < nEndPos && !bStop) IF-y/]  
{ TIt\  
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try{ ez.a  
URL url = new URL(sURL); 0FY-e~xr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &%GAPs%  
httpConnection.setRequestProperty("User-Agent","NetFox"); iK+Vla`}  
String sProperty = "bytes="+nStartPos+"-"; A_WaRYG  
httpConnection.setRequestProperty("RANGE",sProperty); F3]VSI6^E,  
Utility.log(sProperty); Lq1?Y  
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InputStream input = httpConnection.getInputStream(); 1r_V$o$  
//logResponseHead(httpConnection); -%gEND-AP  
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byte[] b = new byte[1024]; Pqw<nyC.  
int nRead; ^6R(K'E}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ir5|H|b<  
{ Jj\lF*B  
nStartPos += fileAccessI.write(b,0,nRead); awvP;F?q|  
//if(nThreadID == 1) $COjC!M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \v5;t9uBZ  
} H0sTL#/L\  
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Utility.log("Thread " + nThreadID + " is over!"); esQ$.L
 
bDownOver = true; NdSuOkwwt  
//nPos = fileAccessI.write (b,0,nRead); Ej 5_d  
} bk;uKV+<  
catch(Exception e){e.printStackTrace ();} XZM@Rys  
} ;gSRpTS:  
} y1T(R#  
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//打印回应的头信息 4#7*B yvf  
public void logResponseHead(HttpURLConnection con) QIlZZ  
{ "}`)s_rt  
for(int i=1;;i++) S4[#[w`=  
{ _ZFEo< `'  
String header=con.getHeaderFieldKey(i); o kA<  
if(header!=null) P\<:.8@$S  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); I[v`)T'_{  
Utility.log(header+" : "+con.getHeaderField(header)); W]7/
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else .-/IV^lGv  
break; .|5$yGEF_+  
} **kix  
} >:> W=  
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public void splitterStop() qIQRl1Tw;V  
{ n*A1x
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bStop = true; _oCNrjt9  
} {\%I;2X  
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} B(94;,(  
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/* YzQ1c~
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**FileAccess.java |\?u-O3  
*//文件访问(定位，写) {?IbbT  
package NetFox; 9A} *  
import java.io.*; #Xox2{~  
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public class FileAccessI implements Serializable{ -~lq <M  
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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 25-h5$s  
RandomAccessFile oSavedFile; gCC7L(1  
long nPos; AH5;6Q  
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0 }od Q#  
public FileAccessI() throws IOException QAp]cE1ew  
{ 0]iaNR %  
this("",0); #Gg^QJ*  
} ,NS*`F[O  
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public FileAccessI(String sName,long nPos) throws IOException _W_< bI34  
{ SeDk/}/~e  
oSavedFile = new RandomAccessFile(sName,"rw"); ;%^=V#
  
this.nPos = nPos; cPNc$^Y  
oSavedFile.seek(nPos); O.ce=E  
} vQK/xg  
bIyg7X)/  
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public synchronized int write(byte[] b,int nStart,int nLen) URrx7F98  
{ B6k<#-HAT  
int n = -1; 6X%g-aTs  
try{ =(D"(OsQ/  
oSavedFile.write(b,nStart,nLen); h )5S4)  
n = nLen; @;P ;i
I  
} WEif&<Y  
catch(IOException e) pC>h"Hy  
{ CCe>*tdf  
e.printStackTrace (); |&rCXfC  
} N\ !  
/}m*|cG/  
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return n; y7fy9jQ 8.  
} SnmUh~`L~  
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} @:9Gs!!  
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/* ~;#}aQYo  
**SiteInfoBean.java mA+:)?e5~  
*/ ()l3X.t,$  
package NetFox; ~BmA!BZV`  
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public class SiteInfoBean { *??lwvJp  
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 |50sGJE(  
private String sSiteURL; //Site's URL
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private String sFilePath; //Saved File's Path
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private String sFileName; //Saved File's Name X&?s:A  
private int nSplitter; //Count of Splited Downloading File ;x/eb g  
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public SiteInfoBean() z m$Sw0#(  
{//nSplitter的缺省值为5 Wq1 jTIQ  
//default value of nSplitter is 5 ?l^Xauk4Pj  
this("","","",5); " L`)^  
} &b
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XH$r(@Z\7  
{ YiDOV)  
sSiteURL= sURL; '6 F-%
 
sFilePath = sPath; 96(Mu% l  
sFileName = sName; 6^[4.D  
this.nSplitter = nSpiltter; |2u=3#Jp  
?!U[~Gq  
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} hDW!pnj1  
|j`73@6  
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public String getSSiteURL() VIP7j(#t_g  
{ =\WF +r]V  
return sSiteURL;  Qw}1q!89  
} rQ
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public void setSSiteURL(String value) Mz(Vf1pi%  
{ ?1SsF>|  
sSiteURL = value; rm,`M  
} W8^m-B&  
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public String getSFilePath() ro{!X,_$,  
{ +1!iwmch>  
return sFilePath; Dp ](?Yr  
} j )6  
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public void setSFilePath(String value) |h\7Q1,1~2  
{ S%i^`_=Q  
sFilePath = value; 56 3mz-  
} J, 9NVw$  

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public String getSFileName() bP&QFc  
{ _qxI9Q}<"  
return sFileName; ?BnU0R_r]  
} J,2V&WuV0r  
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public void setSFileName(String value) !qt2,V
 
{ F)LbH&Kn  
sFileName = value; >.iF,[.[F<  
} U#` e~d t<  
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public int getNSplitter() m+TAaK  
{ o$rjGa l  
return nSplitter; kJWg},-\  
} dZU#lg  
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^  
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public void setNSplitter(int nCount) 'a['lF  
{ /T w{JO#Q  
nSplitter = nCount; C$OVN$lL`8  
} oN7SmP_  
} > N~8#C  
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/* |kYlh5/c d  
**Utility.java O$,Fga  
*/ m8q4t,<J  
package NetFox; +[7~:e}DZ  
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public class Utility { i9;  
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public Utility() V(MYReaPC]  
{ U'fP  
cb}"giXQTB  
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} SH%NYjj  
cHjQwl  
//线程睡眠 X0/slOT  
public static void sleep(int nSecond) Bn}woyJdx  
{ AI|vL4*Xd  
try{ mMAN*}`O  
Thread.sleep(nSecond); xe@1H\7:  
} 4Yj1Etq.E  
catch(Exception e) Q_5l.M/9]  
{ cS ~OxAS  
e.printStackTrace (); F-_u/C]  
} PTQ#8(_,  
} |cvU2JI@  
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//日志 n(:<pz  
public static void log(String sMsg) >Bt82ibN  
{ 5\mRH  
System.err.println(sMsg); ]}2)U  
} ]PXM;w  
osW"wh_
  
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public static void log(int sMsg) TZn 15-O  
{ %w`d  
System.err.println(sMsg); m'o dVZ7  
} .wfydu)3  
} SE'Im  
'6so(>|  
g'"~'  
/* #}`sfaT  
**TestMethod.java ~6G `k^!  
*/ &7L7|{18  
package NetFox; @DN/]P  
8&<mg;H,  
jK|n^5\  
public class TestMethod { J4Gzp~{  
*uvM6F$ut  
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public TestMethod() Obs#2>h  
{ ///xx/weblogic60b2_win.exe  vy<W4  
try{ +|A`~\@N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'Y38VOI%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]C_+u_9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'VDWJTia  
fileFetch.start(); !/FRL<mp  
} 7=^{~5#  
catch(Exception e){e.printStackTrace ();} U3(+8}Q  
=[B\50]  
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} BWt`l,nF  
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o) )` "^  
public static void main(String[] args)
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{ inut'@=G/  
new TestMethod(); !T6R[  
} Oa|c ?|+  
} |RX#5Q>z  
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