http断点续传简单实现（java)

/* T`Jj$Lue{
 
**SiteFileFetch.java :Qekv(z  
*/ !^h{7NmP[  
package NetFox; l`V^d  
import java.io.*; 0Xe?{!@a  
import java.net.*; :tTP3t5  
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public class SiteFileFetch extends Thread { XW2{I.:in>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8 FJ>W.  
long[] nStartPos; //开始位置 m0$~O5|4  
long[] nEndPos; //结束位置 -h|YS/$f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 RY\[[eG  
long nFileLength; //文件长度 ! ,v!7I  
boolean bFirst = true; //是否第一次取文件 zmEg4v'I  
boolean bStop = false; //停止标志 FKVf_Ncf%
 
File tmpFile; //文件下载的临时信息 A2xfNY<  
DataOutputStream output; //输出到文件的输出流  0+P[
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2(%C  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ug=)_~  
{ 6+Bccqn|  
siteInfoBean = bean; Lfj]Y~*z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ic,V,#my  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Q9C;_Up  
if(tmpFile.exists ()) X1J
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{ |."thTO  
bFirst = false; @*
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read_nPos(); '4x uH3  
} wFHz<i!jr&  
else ta)'z@V@g  
{ r'/H3  
nStartPos = new long[bean.getNSplitter()]; rF>7 >wq  
nEndPos = new long[bean.getNSplitter()]; FsXqF&{  
} 9[7Gxmf  
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} E5EA
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public void run() `~S; UG  
{ ~,: FZ1wh  
//获得文件长度 %Q2<bj]  
//分割文件 iAWd 9x  
//实例FileSplitterFetch __Tg1A  
//启动FileSplitterFetch线程 PL6f**{-  
//等待子线程返回 ~ v21b?   
try{ bFt$u]Yvo  
if(bFirst) y"o@?bny  
{ G
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nFileLength = getFileSize(); ns/L./z  
if(nFileLength == -1) }0(.HMiGj  
{ hiM nU  
System.err.println("File Length is not known!"); }c1?:8p  
} kd3vlp  
else if(nFileLength == -2) n\x@~ SzrX  
{ cf7UV6D g  
System.err.println("File is not access!"); hCX_^%  
} <8_~60  
else j1Q"s(  
{ ^]A,Q%1q^  
for(int i=0;i<nStartPos.length;i++) DGY?4r7>y  
{ S.$/uDwo  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P+j5_V{\b  
} _,C>+dv)  
for(int i=0;i<nEndPos.length-1;i++) 0wlKBwf`J  
{ =iEQE  
nEndPos = nStartPos[i+1]; `r$c53|<u  
} (uk-c~T!u  
nEndPos[nEndPos.length-1] = nFileLength; tXWhq  
} 9R6]OL)p  
} y~ZYI]` J  
6$k"B/k  
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//启动子线程 S~+er{,ht4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |_ u  
for(int i=0;i<nStartPos.length;i++) TTSyDl  
{ 1[&V6=n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $QB~ x{v@n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  `[=3_  
nStartPos,nEndPos,i); ]3/_?n-"`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {0t-Q k  
fileSplitterFetch.start(); &P,z$H{o@  
} B{^ojV;]m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G7yR&x^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", btV Tt5  
nEndPos = " + nFileLength); nR2pqaKc  
// fileSplitterFetch[nPos.length-1].start(); $ZEwz;HNo  
:w+2L4lGs  
l)^sE)  
//等待子线程结束 'Rg6JW\  
//int count = 0; "Om4P|  
//是否结束while循环 pm 4"Q!K  
boolean breakWhile = false; c%bGVRhE  
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while(!bStop) i4XE26B;e  
{ $0OWPC1  
write_nPos(); GOII B  
Utility.sleep(500); [|)Eyd[G  
breakWhile = true; X4bB  
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for(int i=0;i<nStartPos.length;i++) BnL[C:|  
{ S.#IC lV  
if(!fileSplitterFetch.bDownOver) k-`5TmW  
{ ZI0C%c.~  
breakWhile = false; t;?TXAA  
break; 6hvmp  
} 42Vz6 k:  
} X^!1MpEQ  
if(breakWhile) {#]vvO2~$  
break; I5$@1+B  
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;Wws;.~  
//count++; REe<k<>p~  
//if(count>4) >Wbt_%dKy  
// siteStop(); l1utk8'-  
} s:fy *6=[Z  
MBO3y&\S4  
>kLUQ%zE@  
System.err.println("文件下载结束！"); Gop;!aV1*  
} u0M? l  
catch(Exception e){e.printStackTrace ();} < SIe5"{  
} !|1GraiS  
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n.
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//获得文件长度 jQgy=;?Lwm  
public long getFileSize() iO 9fg  
{ j%V95M%$  
int nFileLength = -1; G
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try{ r@XH=[:  
URL url = new URL(siteInfoBean.getSSiteURL()); _eE hIQ9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {);S6F$[3  
httpConnection.setRequestProperty("User-Agent","NetFox"); J!5>8I(_wX  
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int responseCode=httpConnection.getResponseCode(); V\ 7O)g
 
if(responseCode>=400) C]xKdPQj%  
{ ZMI!Sl  
processErrorCode(responseCode); 9AxeA2/X  
return -2; //-2 represent access is error KqE
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} )225ee>
 
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String sHeader; BM@:=>ypQ  
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for(int i=1;;i++) has \W\(  
{ ^F*G  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h5x_Vjj  
//Utility.log(in.readLine()); +].Zs<  
sHeader=httpConnection.getHeaderFieldKey(i); T/A[C  
if(sHeader!=null) #})OnM^],  
{ _I&];WM\  
if(sHeader.equals("Content-Length")) w,<nH:~  
{ + \DGS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3V,$FS]  
break; 4}4K6y<q  
} "'@iDq%y  
} cr&sI=i  
else SXA`o<Ma  
break; AaVj^iy/X  
} L~,x~sLd  
} mX2(SFpJar  
catch(IOException e){e.printStackTrace ();} /]mfI&l+9  
catch(Exception e){e.printStackTrace ();} ~ PO)>;  
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Utility.log(nFileLength); c']3N  
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return nFileLength; " ^t3VjN  
} aBH!K   
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//保存下载信息（文件指针位置） xUiSAKrcM  
private void write_nPos() 4490l"  
{  &Ow[  
try{ z/B[quSio  
output = new DataOutputStream(new FileOutputStream(tmpFile)); KKPQ[3g  
output.writeInt(nStartPos.length); Y6>@zznk  
for(int i=0;i<nStartPos.length;i++) J`&*r;""V  
{ fO;#;p.  
// output.writeLong(nPos); 7kQZ$sLc  
output.writeLong(fileSplitterFetch.nStartPos); fG+/p 0sJ?  
output.writeLong(fileSplitterFetch.nEndPos); |Sne\N>%  
} -*Voui
  
output.close(); jO|D#nC  
} C6$F.v  
catch(IOException e){e.printStackTrace ();} *~t&Ux#hj  
catch(Exception e){e.printStackTrace ();} vy <(1\  
} <3[,bTIk  
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//读取保存的下载信息（文件指针位置） )
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private void read_nPos() s$V'|Pt  
{  8>}k5Qu  
try{ 0 e}N{,&Y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E
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int nCount = input.readInt(); d3$*z)12`  
nStartPos = new long[nCount]; _I"T(2Au  
nEndPos = new long[nCount]; <6 LpsM}  
for(int i=0;i<nStartPos.length;i++) Qx B0I/ {  
{ |wnXBKV(
  
nStartPos = input.readLong(); )} I>"n  
nEndPos = input.readLong(); mHm"QBa!  
} q0Hor  
input.close(); O?6ph4'  
} 8"fZ>XQ  
catch(IOException e){e.printStackTrace ();} b6@(UneVM  
catch(Exception e){e.printStackTrace ();} Zj(2
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} |;G9K`8  
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private void processErrorCode(int nErrorCode) /$q9 Kxb  
{ +@U}gk;#c  
System.err.println("Error Code : " + nErrorCode); rq[+p  
} d]89DdZk  
1Qc>A8SU  
2|LgUA?<  
//停止文件下载 *8ZaG]L  
public void siteStop() e^N6h3WF  
{ Kx-s95t  
bStop = true; C EzTErn  
for(int i=0;i<nStartPos.length;i++) _{eH" ,(  
fileSplitterFetch.splitterStop(); >uu]
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} {Q%"{h']  
} N"tEXb/,
 
//负责部分文件的抓取 3gUGfedi  
**FileSplitterFetch.java TJ&Z/k3-  
*/ }m`+E+T4  
package NetFox; \:'|4D]'I  
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import java.io.*; yF~iVt  
import java.net.*; ]TE,N$X  
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public class FileSplitterFetch extends Thread { q ,C)AZ  
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String sURL; //File URL >ZE8EL  
long nStartPos; //File Snippet Start Position <~rf;2LZ  
long nEndPos; //File Snippet End Position /2<1/[#  
int nThreadID; //Thread's ID c{qoASc?  
boolean bDownOver = false; //Downing is over x#-+//  
boolean bStop = false; //Stop identical \-Oq/g{j  
FileAccessI fileAccessI = null; //File Access interface /3(|P  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -0 e&>H%  
{ gbC!>LV  
this.sURL = sURL; yY3Mv/R  
this.nStartPos = nStart; 6r|BiHP  
this.nEndPos = nEnd; =GP~h*5es  
nThreadID = id; &fyT}MA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xE[CNJ%t^,  
} |i}5vT78  
{J?#KHF'|  
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public void run() qoifzEc`U  
{ ug|'}\LY  
while(nStartPos < nEndPos && !bStop) ^:(:P9h  
{ b<1k$0J6  
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try{ bG'"l qn  
URL url = new URL(sURL); 5bfd8C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |t1ij'N  
httpConnection.setRequestProperty("User-Agent","NetFox"); S7I8BS[*v  
String sProperty = "bytes="+nStartPos+"-"; :k-(%E](  
httpConnection.setRequestProperty("RANGE",sProperty); VSxls  
Utility.log(sProperty); U1.w%b,  
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InputStream input = httpConnection.getInputStream(); 6F@2:]W  
//logResponseHead(httpConnection); *Dz<Pi^  
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byte[] b = new byte[1024]; kW 7$  
int nRead; 3 zF"GT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '&|]tu:q  
{ N9[2k.oBH  
nStartPos += fileAccessI.write(b,0,nRead); f19~B[a  
//if(nThreadID == 1) b{Qg$ZJeR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); No'^]r  
} aS7%x>.A!  
*<5zMSZO  
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Utility.log("Thread " + nThreadID + " is over!"); p5`d@y\hj  
bDownOver = true; g4`)n`  
//nPos = fileAccessI.write (b,0,nRead); 1z#0CX}Y/H  
} pYtvenBy  
catch(Exception e){e.printStackTrace ();} -9L[eYn  
} /IkSgKJiz\  
} B <CK~ybY  
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//打印回应的头信息 u`Sg'ro  
public void logResponseHead(HttpURLConnection con) z.xOT;t  
{ I1TzP
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for(int i=1;;i++) =` %iv|>r0  
{ ,^>WCG  
String header=con.getHeaderFieldKey(i); q3~RK[OCq  
if(header!=null) ]h`<E~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k *#fN(_  
Utility.log(header+" : "+con.getHeaderField(header)); z1WF@Ej  
else 2".^Ma^D!  
break; J4xJGO  
} uqN:I)>[P  
} V&j |St[  
/=|5YxY  
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public void splitterStop() +dt b~M  
{ On^jHqLaE  
bStop = true; .2si[:_(p  
}  =Y0>b4  
,J(+%#$UT  
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} 4Y=sTXbFt  
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/* R>3a?.X  
**FileAccess.java X`,]@c%C`  
*//文件访问(定位，写) i;yr=S,a0/  
package NetFox; "(U%Vg|)  
import java.io.*; !aVwmd'9  
l5 FM>q  
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public class FileAccessI implements Serializable{ #]BpTpRAe<  
c T[.T#I  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 WC?}a^
8  
RandomAccessFile oSavedFile; cITF=Ez  
long nPos; :EXH8n&|  
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public FileAccessI() throws IOException bc".R]  
{ @`</Z)  
this("",0); oQkY@)3.w  
} g.cD3N  
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public FileAccessI(String sName,long nPos) throws IOException xEA%UFB.!G  
{ ~HR/FGe?N  
oSavedFile = new RandomAccessFile(sName,"rw"); LPOZA`  
this.nPos = nPos; |H,g}XWMU  
oSavedFile.seek(nPos); nt"8kv  
} {O
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public synchronized int write(byte[] b,int nStart,int nLen) [~ Wiy3n  
{ `F#<qZSR  
int n = -1; {
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try{ .Fz5K&E=  
oSavedFile.write(b,nStart,nLen); f +#  
n = nLen; K}]0<\N  
} zW@OSKq4  
catch(IOException e) 6Wos6_  
{ \n@S.Y?P  
e.printStackTrace (); K-xmLEu  
} iz2I4 _N  
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return n; 
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} }x[d]fcC  
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} pY3N7&m\:  
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/* #$vef  
**SiteInfoBean.java xELnik_L2  
*/ .CrrjS w  
package NetFox; ~)S Q{eK?&  
H& #Od?  
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public class SiteInfoBean { >};6>)0  
zEQ<Q\"1  
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private String sSiteURL; //Site's URL ,sAN,?eG~  
private String sFilePath; //Saved File's Path [n`SXBi+n  
private String sFileName; //Saved File's Name LNp%]*h  
private int nSplitter; //Count of Splited Downloading File %^L:K5V  
)8c`o  
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public SiteInfoBean() 8e'0AI_>  
{//nSplitter的缺省值为5 ZO
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//default value of nSplitter is 5 0d-w<lg9  
this("","","",5); @~!1wPvF`I  
} a<.7q1F  
>.D0McQg  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) + *YGsM`E9  
{ BO5g
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sSiteURL= sURL; @-z#vJ5Qe{  
sFilePath = sPath; QK5y%bTSA  
sFileName = sName; 728}K^7:  
this.nSplitter = nSpiltter; iA~b[20&  
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} fwy-M:  
8ycmvpJ  
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public String getSSiteURL() O<R6^0B42  
{ xM1>kbo|  
return sSiteURL; W|U!kqU  
} h(,SAY_  
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public void setSSiteURL(String value) wz*QB6QtU  
{ guC/eSxv  
sSiteURL = value; i^{.Q-  
} c<V.\y0x  
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public String getSFilePath() 2`#jw)dM;}  
{ $'f<4  
return sFilePath; p{j }%)6n  
} YyX/:1 sg>  
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public void setSFilePath(String value) , #yE#8
 
{ R v9?<]  
sFilePath = value; a;Ic!:L
 
} {~yj]+Im  
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public String getSFileName() %$j)?e  
{ EXDtVa Ot  
return sFileName; j%iz>  
} D4yJ:ATO&  
7N^9D H{`  
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public void setSFileName(String value) 5_+vjV;5  
{ -OpI,qyS  
sFileName = value; 4#uWj?u  
} $Yt29AQ  
\#5t%t
 
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public int getNSplitter() O6P0Am7s  
{ +dm&XW >  
return nSplitter; 9?r|Y@xh]  
} w>T1
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public void setNSplitter(int nCount) w:Fi 2a
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{ KQ3]'2q  
nSplitter = nCount; FxSBxz<N-A  
} (Q !4\Gy  
} <@n/[ +3  
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@oC8

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/* E%\iNU!  
**Utility.java 0SV#M6`GX  
*/ t=iSMe  
package NetFox; 9+.0ZP?  
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public class Utility { }cyHR1K  
#Nxk3He]8  
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public Utility() @FL?,_,Y{  
{ ~=HN30  
w[z^B&  
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} /-<S F
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zpr`  
//线程睡眠 <Mo_GTOC!  
public static void sleep(int nSecond) ]{
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{ X'Q$v~/  
try{ \_FX}1Wc2.  
Thread.sleep(nSecond); In|:6YDL&  
} ~#iRh6^98  
catch(Exception e) KzZ! CB\  
{ >2`)S{pBD  
e.printStackTrace (); ^~(vP:  
} K1Nhz'^=D  
} .]%PnJM9K  
qIK"@i[ uq  
//日志 cD^n}'ej  
public static void log(String sMsg) I,vy__sZ  
{ J_R54Y~vu  
System.err.println(sMsg); m8H|cQ@Uu  
} S pDVD  
V'~]b~R  
bp2l%A;  
public static void log(int sMsg) R-J\c+C>W  
{ Nh~ Hh(  
System.err.println(sMsg); VO>A+vx3M  
} +Y,>ftN  
} d8Jy$,/`?  
.pQH>;k]K  
?:Y{c#w>  
/* JpE4 o2  
**TestMethod.java zJ7vAL
  
*/ `@ULG>   
package NetFox; "aK3 ylz;  
DDn@M|*$  
B2VC:TG>  
public class TestMethod { dlN(_6>b  
Gvv~P3Dm  
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public TestMethod() r#*kx#"  
{ ///xx/weblogic60b2_win.exe oabc=N!7
r  
try{ {bL6%._C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,Cj1S7GFR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /K2VSj3\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [wP;g'F  
fileFetch.start(); O^|dc=  
} `w6\II)aB  
catch(Exception e){e.printStackTrace ();} z`((l#(  
eIK8J,-  
+ZtqR  
} n(,b$_JK7  
V0z.w:-  
G>&=rmK"  
public static void main(String[] args) pj&vnX6O^  
{ k_#ra7zP  
new TestMethod(); -
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} 64>E|w  
} :j9{n ,F  
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