http断点续传简单实现（java)

/* GBTwQYF  
**SiteFileFetch.java Eb8~i_B-  
*/ 3fUiYI|&7  
package NetFox; ~Zw37C9J  
import java.io.*; !iL6/  
import java.net.*; y[/:?O}g4  
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public class SiteFileFetch extends Thread { 5S ) N&%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4,&f#=Y  
long[] nStartPos; //开始位置 1*f/Y9 Z  
long[] nEndPos; //结束位置 ?jsgBol  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J
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long nFileLength; //文件长度 PB)vE  
boolean bFirst = true; //是否第一次取文件 E_0i9  
boolean bStop = false; //停止标志 ~i]4~bkH2  
File tmpFile; //文件下载的临时信息 sw50lId  
DataOutputStream output; //输出到文件的输出流 YlXqj\a  
`[h&Q0Du6  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） braI MIQ`  
public SiteFileFetch(SiteInfoBean bean) throws IOException FzF#V=9lP  
{ %v0;1m  
siteInfoBean = bean; ";upu  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); xg4wtfAbS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )Wk&c8|y  
if(tmpFile.exists ()) hbSKlb0d  
{ Of-8n-  
bFirst = false; EgRuB@lw76  
read_nPos(); Rsx?8Y^5  
} -,ojZFyRi  
else Y}h&dAr  
{ 3
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nStartPos = new long[bean.getNSplitter()]; %6x3G  
nEndPos = new long[bean.getNSplitter()]; Knp}88DR^j  
} V"T5<HA9  
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4 g8t  

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} W]D+[mpgK  
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public void run() m
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{ z3M6<.K  
//获得文件长度 ?[.g~DK,  
//分割文件 L?(m5u~b  
//实例FileSplitterFetch wS [k}  
//启动FileSplitterFetch线程 
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//等待子线程返回 M(:_(4~  
try{ N.vkM`Z  
if(bFirst) A{wk$`vH
  
{ Pa{b
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nFileLength = getFileSize(); ?{~. }Vn  
if(nFileLength == -1) p3B_NsXVZ  
{ K,!f7KKo  
System.err.println("File Length is not known!"); {D
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} BPu>_$C  
else if(nFileLength == -2) n>YgL}YZ?  
{ KssIoP
 
System.err.println("File is not access!"); Pu}PE-b  
} ;(s.G-9S  
else }<q=Zq+  
{ /+m7
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for(int i=0;i<nStartPos.length;i++) ^t[br6G  
{ .VkLF6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xw3A|Aj?r  
} XeozRfk%J|  
for(int i=0;i<nEndPos.length-1;i++) R7Ns5s3X  
{ \r}*<CRr6  
nEndPos = nStartPos[i+1]; ;nb>IL  
} }b>e lz  
nEndPos[nEndPos.length-1] = nFileLength; V_9>Z?  
} a61?G!]  
} Q[bIkvr|  
}S9uh-j6l  
h=_h,?_  
//启动子线程 KvEZbf3f  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ifj%"RI  
for(int i=0;i<nStartPos.length;i++) t`0(5v  
{ ^ |>)
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 30h1)nQ$h}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), R[2h!.O8  
nStartPos,nEndPos,i); `4"&_ltD  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9-?kamA  
fileSplitterFetch.start(); y9Q"3LLic`  
} 9|hPl-. .W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F:-6Htmj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;W!hl<``d*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cWa>rUsF  
nEndPos = " + nFileLength); gC/-7/}  
// fileSplitterFetch[nPos.length-1].start(); fG /wU$B  
]K%D$x{+\  
Ay\!ohIS3  
//等待子线程结束 _1?Fyu&<5  
//int count = 0; mGUl/.;yp-  
//是否结束while循环 r<.*:]L
 
boolean breakWhile = false; =_d-MJy~6  
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while(!bStop) =Y5*J#  
{ tA9(N>[*  
write_nPos(); 1;9 %L@  
Utility.sleep(500); >V3pYRA   
breakWhile = true; 4JjO.H  
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++0xa%:  
for(int i=0;i<nStartPos.length;i++) EB>rY  
{ ?T:$:IHw  
if(!fileSplitterFetch.bDownOver) B9h>  
{ !O#NP!  
breakWhile = false; .:jfNp~jt  
break; [u`9R<>c"U  
} FZtILlw  
} c
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if(breakWhile) D\V (r\i  
break; N%`Eq@5  
)IZ~!N|-w  
vM2\tL@"  
//count++; JY@x.?N5$  
//if(count>4) \JEI+A PY*  
// siteStop(); Gex%~';+q  
} ( j~trpe,  
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System.err.println("文件下载结束！"); >a1ovKF  
} AT,?dxP J  
catch(Exception e){e.printStackTrace ();} h3
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} |CjE}5Op>  
 W,)qE^+  
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//获得文件长度 GGchNt  
public long getFileSize() pxs`g&3yd  
{ j*;/Cah]k  
int nFileLength = -1; RJZ4fl  
try{ %O3 r>o=  
URL url = new URL(siteInfoBean.getSSiteURL()); D*#r V P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '
5"`H>[  
httpConnection.setRequestProperty("User-Agent","NetFox"); %j?<v@y  
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int responseCode=httpConnection.getResponseCode(); !U!}*clYL  
if(responseCode>=400) zos#B30  
{ @VcSK`  
processErrorCode(responseCode); T5di#%: s  
return -2; //-2 represent access is error 2*1s(Jro  
} !'EE
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$:MO/Suz{  
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String sHeader; K%"cVqb2V  
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for(int i=1;;i++) D2}nJFR ]  
{ {CR'Z0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .4wp  
//Utility.log(in.readLine()); )7Ed}6%  
sHeader=httpConnection.getHeaderFieldKey(i); qZ7/d,w  
if(sHeader!=null) 8o;9=.<<~u  
{ X`k[ J6  
if(sHeader.equals("Content-Length")) u)fmXoQ  
{ !]k$a  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3_tO  
break; Kr]`.@/.S  
} ]gQ4qu5  
} 5:H9B  
else *xOrt)D=  
break; GlVD!0  
} T9+ ?A l  
} +}@HtjM  
catch(IOException e){e.printStackTrace ();} VJeN m3WNb  
catch(Exception e){e.printStackTrace ();} nn_j"Nu  
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^KJIT3J(#  
Utility.log(nFileLength); *tda_B 2  
}9xEA[@;  
}$ Am;%?p  
return nFileLength; Dyj5a($9"{  
} l&
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//保存下载信息（文件指针位置） 2|)3Ly9  
private void write_nPos() ~a5p_xP  
{ =,~h]_\_  
try{ :,=no>mMx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); v&B*InR?+  
output.writeInt(nStartPos.length); /0mbG!Ac  
for(int i=0;i<nStartPos.length;i++) +BRmqJ3  
{ B&`hvR  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); YGObTIGJvf  
output.writeLong(fileSplitterFetch.nEndPos); oP".>g-.  
} [2!K 6  
output.close(); 2c <Qh=  
} g(Jzu'  
catch(IOException e){e.printStackTrace ();} v 6?{g  
catch(Exception e){e.printStackTrace ();} !z;a>[T'  
} sgo({zA`i  
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//读取保存的下载信息（文件指针位置） ']+-u{+#  
private void read_nPos() 1Q6WpS  
{ e1X*}OI  
try{ ^Q]*CU+C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3I?? K)Yl  
int nCount = input.readInt(); _1`*&k JL~  
nStartPos = new long[nCount]; Z2WAVSw  
nEndPos = new long[nCount]; HZdmL-1Z^+  
for(int i=0;i<nStartPos.length;i++) _Va!Ky =]  
{ */n)_  
nStartPos = input.readLong(); 9(Vq@.;Z`j  
nEndPos = input.readLong(); /}Y>_87  
} ]}cai1  
input.close(); })|+tZ  
} 0!rU,74I=  
catch(IOException e){e.printStackTrace ();} H'$g!Pg  
catch(Exception e){e.printStackTrace ();}  XGEAcN  
} K^k1]!W=  
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7{:| )  
private void processErrorCode(int nErrorCode) RR><so%  
{ J56+eC(  
System.err.println("Error Code : " + nErrorCode); Te~"\`omJ3  
} a$g4)0eS  
d(w $! $"h  
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//停止文件下载 5DfAL;o!  
public void siteStop() <$n%h/2%  
{ WJZW5 Xt  
bStop = true; 9/RbfV[)  
for(int i=0;i<nStartPos.length;i++) SM5i3EcFYP  
fileSplitterFetch.splitterStop(); UcDJ%vI  
[K[tL|EK  

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} 4em7PmT  
} vfJ}t#%UH  
//负责部分文件的抓取 pFGK-J  
**FileSplitterFetch.java =V1k'XJ  
*/ S'HM|&  
package NetFox; O9]j$,i  
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import java.io.*; ;"&^ckP  
import java.net.*; !J[3U   
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~ @Ib:M  
public class FileSplitterFetch extends Thread { Bm%:Qc*  
xmTa$tR+  
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String sURL; //File URL *J?QXsg  
long nStartPos; //File Snippet Start Position d5]9FIj  
long nEndPos; //File Snippet End Position Y*O7lZuF%  
int nThreadID; //Thread's ID S)z jfJR  
boolean bDownOver = false; //Downing is over BN@*CG  
boolean bStop = false; //Stop identical dh%C@n:B  
FileAccessI fileAccessI = null; //File Access interface \i "I1xU  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }3Pz{{B&+O  
{ F$ x@]  
this.sURL = sURL; &Hc8u,|  
this.nStartPos = nStart; GdR>S('  
this.nEndPos = nEnd; 9
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nThreadID = id; {J%hTjCw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /Yc!m$uCW  
} '@wYr|s4  
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public void run() X\hD4r"  
{ '+Dn~8Y+9  
while(nStartPos < nEndPos && !bStop) FJv=5L  
{ &7T0nB/)  

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6 EE7<&  
try{ [Zl  
URL url = new URL(sURL); Et%s,zeA{2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x
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httpConnection.setRequestProperty("User-Agent","NetFox"); @h X  
String sProperty = "bytes="+nStartPos+"-"; vyERt^z  
httpConnection.setRequestProperty("RANGE",sProperty); d37l/I  
Utility.log(sProperty); T%KZV/  
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InputStream input = httpConnection.getInputStream();
+XJj:%yt  
//logResponseHead(httpConnection); u=jF\W9  
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byte[] b = new byte[1024]; 4 Yc9Ij  
int nRead; vd SV6p.d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4<70mUnt  
{ >;nE.]  
nStartPos += fileAccessI.write(b,0,nRead); De4UGX  
//if(nThreadID == 1) IQoz8!guh:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 85m[^WGyh  
} v@LK3S/!3  
$/5Jc[Ow  
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Utility.log("Thread " + nThreadID + " is over!"); `z-4OJ8~  
bDownOver = true; 7NMQUN7k'  
//nPos = fileAccessI.write (b,0,nRead); 2K!3+D"  
} #SQT!4  
catch(Exception e){e.printStackTrace ();} 4s^5t6  
} -wC;pA#o  
} z6B/H2  
'[~NRKQJ  
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//打印回应的头信息 5 r"`c  
public void logResponseHead(HttpURLConnection con) 0MF[e3)a  
{ .Hl]xI$;+  
for(int i=1;;i++) -
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{ mgL~ $  
String header=con.getHeaderFieldKey(i); R?(0:f  
if(header!=null) (i1FMd}G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1@P/h#_Vr  
Utility.log(header+" : "+con.getHeaderField(header)); k)b}"' I  
else c#$B;?  
break; 05LVfgJ'q  
} Cv>|>Ob#  
} )(9>r/bq  
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public void splitterStop() EJ.oq*W!*J  
{ hewX)  
bStop = true; x %L2eXL  
} k8F<j)"  
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} 5CueD]  
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/* $}jp=?,t  
**FileAccess.java
7$<.I#x  
*//文件访问(定位，写) wXMKQ)$(  
package NetFox; tU>wRw=
d  
import java.io.*; 1LZ?!Lw  
(#BkL:dg
 
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public class FileAccessI implements Serializable{ fB:9:NX  
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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 2xhwi.u  
RandomAccessFile oSavedFile; Sf B+;i'D  
long nPos; Yewn  
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public FileAccessI() throws IOException wV+ W(  
{ sNc(aGvy  
this("",0); 9AD`,]b  
} C~ t?<  
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public FileAccessI(String sName,long nPos) throws IOException 0Jm6 r4s?  
{ 9JBPE  
oSavedFile = new RandomAccessFile(sName,"rw"); 01g=Cg  
this.nPos = nPos; >N@tInE  
oSavedFile.seek(nPos); {UX?z?0T
 
} /1F%w8Iqh  
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public synchronized int write(byte[] b,int nStart,int nLen) rIH/<@+  
{ 'C8VD+p  
int n = -1; [mn@/qf  
try{ AqB5B5}  
oSavedFile.write(b,nStart,nLen); SG_
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n = nLen;
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} :tp2@*]9Z  
catch(IOException e) =@AWw:!:,  
{ V&
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e.printStackTrace (); J 05@SG':  
} Yz=(zj  
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return n; t.$3?"60~  
}
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} 7Ab&
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/* }l~|c{WH`  
**SiteInfoBean.java L^i=RGx  
*/ 7yD=~l\Bbs  
package NetFox; M$~3`n*^  
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public class SiteInfoBean { Ef{rY|E  
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private String sSiteURL; //Site's URL 'bJ!~ML&  
private String sFilePath; //Saved File's Path G3'>KMa.  
private String sFileName; //Saved File's Name ?YWfoH4mS  
private int nSplitter; //Count of Splited Downloading File ,(dg]7  
bO 2>ced  
GmP)"@O](;  
public SiteInfoBean() 0{^vqh.La  
{//nSplitter的缺省值为5 1rKKph  
//default value of nSplitter is 5 u\wdb^8ds  
this("","","",5); 6E/>]3~!  
} wwrP7T+d  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0<_|K>5dS|  
{ $3<,"&;Ecs  
sSiteURL= sURL; 6w(Mb~[n  
sFilePath = sPath; +KgoLa  
sFileName = sName; ZUP\)[~  
this.nSplitter = nSpiltter; =}>wxO  
x=T`i-M  
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} ?j;e/r.  
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&IsQgS7R  
public String getSSiteURL() =M'M/vKD  
{ nwswy]e8/  
return sSiteURL; +^ a9i5  
} bP\0S@1YL  
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public void setSSiteURL(String value) =y-L'z&r  
{ CF"$&+s9  
sSiteURL = value; K~ ,|~  
} s3qWTdM  
JYuI~<:  
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public String getSFilePath() VeiJ1=hc  
{ JLUG=x(dA  
return sFilePath; #[0:5$-[  
} ?3X!  
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public void setSFilePath(String value) Q
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{ Atl`J.;G  
sFilePath = value; :W]?6=  
} aEU[k>&  
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public String getSFileName() W%LTcm  
{ .{sKE
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return sFileName; *z[G+JX  
} XndGe=O  
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public void setSFileName(String value) +v4P9V|s  
{ j_N><_Jc  
sFileName = value; rt">xVl  
} 7pMl:\  
3 i<,#FaL  
?xEQ'(UBQ  
public int getNSplitter() #p&&w1  
{ !Ic;;<
 
return nSplitter; 4;"^1 $  
} r_C|gfIP  
x,$N!X  
J-*&&  
public void setNSplitter(int nCount) W}m-5L  
{ #vrxhMo  
nSplitter = nCount; qu]ch&"?U  
} b`"E(S/  
} I)#=#eI*:  

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&:}e`u@5|  
/* L9tjHC]
 
**Utility.java L%](C  
*/ kwxb~~S}h(  
package NetFox; dxqVZksg(9  
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public class Utility { 0dS}pd">k  
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public Utility() *9:oTN  
{ LhM{LUi  
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} s( @w1tS.  
&8'.Gwm}  
//线程睡眠 %Q]u_0P
*  
public static void sleep(int nSecond) lfjY45
=  
{ XL[/)lX{  
try{ (vte8uQe  
Thread.sleep(nSecond); bqugo  
} s2Gi4fY?  
catch(Exception e) Y.I-hl1<r  
{ zJ{?'kp  
e.printStackTrace (); 6o@}k9AN  
} 89@\AjI  
} !NWz  
B;9"=0  
//日志 H /Idc,*  
public static void log(String sMsg) IV{,'+hT  
{ y*2R#jTA  
System.err.println(sMsg); /dTy%hZC}  
} `5 py6,  
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public static void log(int sMsg) ""Ul6hRgv  
{ EtN@ 6xP  
System.err.println(sMsg); bc}X.IC  
} 5,=Yi$x  
} TR!^wB<F  
1);$#Dlt k  
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/* b *IJ +  
**TestMethod.java QS2J271E}  
*/ [?)=3Pp  
package NetFox; Gd
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VM{`CJ2  
public class TestMethod { H+ra w/"  
QX(x6y>Q  
SQ#6~zxl  
public TestMethod() \8\)5#?  
{ ///xx/weblogic60b2_win.exe `x:znp}'  
try{ Oq"(oNG@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YArNJ5z=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ||v=in   
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8f>=.O*)  
fileFetch.start(); }qfr&Ffh@  
} 8Ml&lfn_8  
catch(Exception e){e.printStackTrace ();} A.7:.5Cx'  
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} D|I(2%aC  
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public static void main(String[] args) /nXp5g^6(  
{ &{QB}r  
new TestMethod(); &SS"A*xg  
} Lm+!/e  
} 8?] :>  
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