http断点续传简单实现（java)

/* 5?SE?VC=t  
**SiteFileFetch.java syW[uXNLZ  
*/ x5uz$g  
package NetFox; xOKJOl
 
import java.io.*; Z9$pY=8^?  
import java.net.*; @2hhBW  
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public class SiteFileFetch extends Thread { aOGoJCt C  
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SiteInfoBean siteInfoBean = null; //文件信息Bean S1Y,5,}  
long[] nStartPos; //开始位置 H 4ELIF#@  
long[] nEndPos; //结束位置 fYy w2"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'RKpMdoz  
long nFileLength; //文件长度 ,]wQ]fpt  
boolean bFirst = true; //是否第一次取文件 lwX9:[Z  
boolean bStop = false; //停止标志 !9PAfi?  
File tmpFile; //文件下载的临时信息 / ^d9At614  
DataOutputStream output; //输出到文件的输出流 ^6kl4:{idE  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） k1xx>=md|C  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1a(\F7  
{ j% 7Gje[  
siteInfoBean = bean; lqOpADLS3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E/oLE^yL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ME]4tu  
if(tmpFile.exists ()) onSt%5{P%X  
{ eUQmW^  
bFirst = false; ,4xNW:!j  
read_nPos(); ,Ohhl`q(  
} ,\"x#Cc f  
else V[kJ;YLPN  
{ 1/?Wa  
nStartPos = new long[bean.getNSplitter()]; vc|tp_M67  
nEndPos = new long[bean.getNSplitter()]; #oTVfY#  
} g]L8Jli  
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} 5*Zz_ .  
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public void run() 59D'*!l-  
{ !Z2h?..O  
//获得文件长度 A4@z+ebb l  
//分割文件 zqdkt `  
//实例FileSplitterFetch ty['yV-;a  
//启动FileSplitterFetch线程 h SS9mQ  
//等待子线程返回 dNf9,P_}  
try{ +BtLd+)R  
if(bFirst) .jqil0#)Y"  
{ jc_k\  
nFileLength = getFileSize(); /r'Fq =z  
if(nFileLength == -1) Z72%Bv  
{ c!6v-2ykv  
System.err.println("File Length is not known!"); bS8$[7OhX  
} 7=fNvES2  
else if(nFileLength == -2) xI?'Nh  
{ TDR|*Cs  
System.err.println("File is not access!"); Q3l>xh  
} V)~b+D  
else Z1q<) O1QX  
{ !%t@wQ]\hG  
for(int i=0;i<nStartPos.length;i++) =p[Sd*d  
{ %I
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); paV1o>_Rd  
} b*h:e.q  
for(int i=0;i<nEndPos.length-1;i++) GOdWc9Ta!  
{ 2(GYk
 
nEndPos = nStartPos[i+1]; yxu7YGp%  
} |khFQ(  
nEndPos[nEndPos.length-1] = nFileLength; +0[H`5-^  
} 9'H:pb2  
} XkqsL0\  
G2wSd'n*y  
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//启动子线程 t&43)TPb.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U`~L}w"  
for(int i=0;i<nStartPos.length;i++) Pl'lmUR  
{ h~sTi  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o<48'>[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J#wf`VR%  
nStartPos,nEndPos,i); bz nMD  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9s5s;ntz"  
fileSplitterFetch.start(); ck `td%  
} YR\(*LJL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sqhIKw@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 63\ CE_p  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", j-J/yhWO&  
nEndPos = " + nFileLength); Bj6%mI42hl  
// fileSplitterFetch[nPos.length-1].start(); z[[qrR  
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//等待子线程结束 [Y`E"1f2  
//int count = 0; lQ^"-zO4  
//是否结束while循环 *N
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boolean breakWhile = false; ~u0<c:C^  
/<T{g0s  
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while(!bStop) gA
EB  
{ w$&;s<0  
write_nPos(); Es}`SIe/  
Utility.sleep(500); H'$H@Kn]-  
breakWhile = true; E]vox~xK>  
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for(int i=0;i<nStartPos.length;i++) "\+\,C  
{ -XnIDXM  
if(!fileSplitterFetch.bDownOver) &$T7eOiZ  
{ X^&--@l}T!  
breakWhile = false; f\$_^dV  
break; cY!P


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} HI:
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} N6BOUU]  
if(breakWhile) 45-x$o  
break; W+GBSl
 
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//count++; >f&
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//if(count>4) ;=P!fvHk  
// siteStop(); w?"M  
} (O!CHN!:  
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}vP
(SF6  
System.err.println("文件下载结束！"); >@G"*le*)  
} y~OP9T
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catch(Exception e){e.printStackTrace ();} t}}Ti$$>  
} \O~/^ Y3U!  
73u97oe>1  
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//获得文件长度 }3WP:E
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public long getFileSize()  Jc]k\U  
{ SCn)j:gH;  
int nFileLength = -1; Vy/G-IASb  
try{ $mAyM+ ph[  
URL url = new URL(siteInfoBean.getSSiteURL()); dqBN_P%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /9SoVU8  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'bH~KK5  
8yOhKEPX  
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int responseCode=httpConnection.getResponseCode(); ZjY?T)WE9  
if(responseCode>=400) z&#^9rM"  
{ XLYGhM  
processErrorCode(responseCode); >ZgV8X:  
return -2; //-2 represent access is error X<W${L$G  
} b ~]v'|5[  
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String sHeader; eq"Xwq*  
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U
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for(int i=1;;i++) }{PG^Fc<P  
{ T#Bj5
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G"L`9E<0V  
//Utility.log(in.readLine()); 3,hu3"@k  
sHeader=httpConnection.getHeaderFieldKey(i); |eye) E:  
if(sHeader!=null) g^po$%I '  
{ :YX5%6  
if(sHeader.equals("Content-Length")) OM7AK B=S  
{ fV6ddh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7#
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break; e=#D1
  
} 2*gB~Jn4  
} p,(W?.ZDN?  
else ]i1OssV~>  
break; yP` K [/  
} FH%:NO  
} M djxTr^  
catch(IOException e){e.printStackTrace ();} N<KsQsy=  
catch(Exception e){e.printStackTrace ();} bQN3\mvY  
)L":I  
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Utility.log(nFileLength); I+3=|Vef  
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return nFileLength; |RXXj[z  
} b>#dMRK  
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//保存下载信息（文件指针位置） eqOT@~H  
private void write_nPos() TB<$9FCHK  
{ 9R-2\D]  
try{ "8a ?K
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output = new DataOutputStream(new FileOutputStream(tmpFile)); <wd;W;B  
output.writeInt(nStartPos.length); ?} E M,  
for(int i=0;i<nStartPos.length;i++) -i91nMi]  
{ #Lk~{  
// output.writeLong(nPos); 33~8@]b  
output.writeLong(fileSplitterFetch.nStartPos); z'O+B}  
output.writeLong(fileSplitterFetch.nEndPos); at\u7>;.^k  
} ]j*uD317  
output.close(); :7Uv)@iUk  
} '<e$ c  
catch(IOException e){e.printStackTrace ();} 4}*.0'Hz  
catch(Exception e){e.printStackTrace ();} vwa*'C  
} j`Ek:  
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(?GW/pLK]  
//读取保存的下载信息（文件指针位置） 1BP/,d |+  
private void read_nPos() S$40nM  
{ #_IuB) qy  
try{ {+Wknm%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); oxI?7dy5  
int nCount = input.readInt(); el2<W=^M  
nStartPos = new long[nCount]; &U([Wd?E2  
nEndPos = new long[nCount]; BbL]0i  
for(int i=0;i<nStartPos.length;i++) =CdrhP_  
{ 6p&uifY}tR  
nStartPos = input.readLong(); >b:5&s\9  
nEndPos = input.readLong(); *c$UIg  
} ,S`FxJcE  
input.close(); AG;KXL[V  
} Fs=)*6}&  
catch(IOException e){e.printStackTrace ();} X68.*VHh0  
catch(Exception e){e.printStackTrace ();} 23'{{@30  
} FKhgUnw  
%z.d;[Hs  
im)r4={ 9  
private void processErrorCode(int nErrorCode) P{J9#.Zq&s  
{ /3sX>Rj  
System.err.println("Error Code : " + nErrorCode); '0o^T 7C  
} t0/Ol'kgs  
6iHY{WcDj  
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//停止文件下载 Cy5iEI#  
public void siteStop() {utnbtmu  
{ hl)jE 06  
bStop = true; uc]5p(9Hb  
for(int i=0;i<nStartPos.length;i++) _[l&{,  
fileSplitterFetch.splitterStop(); Z>X]'q03  
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} bTAY5\wB  
} ,C
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//负责部分文件的抓取 ,K30.E  
**FileSplitterFetch.java w?M"`O(  
*/ &5B/>ag1!  
package NetFox; Are0Nj&?
 
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import java.io.*; xbHI4A"Z  
import java.net.*; hKnV
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public class FileSplitterFetch extends Thread { ![]6| G&  
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String sURL; //File URL +Oo-8f*  
long nStartPos; //File Snippet Start Position ;'[?H0Jw'  
long nEndPos; //File Snippet End Position y~M6  
int nThreadID; //Thread's ID %t74*cX  
boolean bDownOver = false; //Downing is over M[-/&;`f@  
boolean bStop = false; //Stop identical fwUF5Y  
FileAccessI fileAccessI = null; //File Access interface $DnR[V}rR!  
`/i/AZ{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1L?W+zMO  
{ 8A-*MU`+  
this.sURL = sURL; vv5rA 6+  
this.nStartPos = nStart; J^PFhu  
this.nEndPos = nEnd;  R;&k/v  
nThreadID = id; _oefp*iWS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7,uD7R_  
} *UG?I|l|I  
$kkL)O*"]  
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public void run() 4&:|h 1  
{ =n@\m<  
while(nStartPos < nEndPos && !bStop) *7L1SjZw  
{ G"Ey%Q2K  
]xJ.OUJy  
/,$V/q+  
try{ +<B"g{dLuX  
URL url = new URL(sURL); 4((p?jbC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :gRVa=}=  
httpConnection.setRequestProperty("User-Agent","NetFox"); N\?__WlBK7  
String sProperty = "bytes="+nStartPos+"-"; 0Xn,q]@Z  
httpConnection.setRequestProperty("RANGE",sProperty); {CTJX2&  
Utility.log(sProperty); ^bdXzj
f  
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InputStream input = httpConnection.getInputStream(); |}X[Yg=FG  
//logResponseHead(httpConnection); ;.R) uCd{=  
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byte[] b = new byte[1024]; /{I-gjovy  
int nRead; E4_,EeC#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cw0uLMqr`  
{ K]dR%j  
nStartPos += fileAccessI.write(b,0,nRead); :TV`uUE  
//if(nThreadID == 1) z|(<Co8#.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :vaVghN\  
} yi(IIW  
EEx:Xk%5hX  
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Utility.log("Thread " + nThreadID + " is over!"); 5HY0 *\  
bDownOver = true; g-m,n=qu  
//nPos = fileAccessI.write (b,0,nRead); 0]nveC$  
}
? 5OK4cR  
catch(Exception e){e.printStackTrace ();} yGX5
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} VT#`l0I}  
} >S{8sN
 
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2zX9c<S=5  
//打印回应的头信息 5EECr \*  
public void logResponseHead(HttpURLConnection con) P{StF`>Y  
{ w:R#F( 'B  
for(int i=1;;i++) FNo.#Z5+b  
{ n(SeJk%>9  
String header=con.getHeaderFieldKey(i); m6gMVon  
if(header!=null) zzd PR}VG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gp'k(rGH  
Utility.log(header+" : "+con.getHeaderField(header)); )6o%6$c  
else wuSotbc/  
break; 6/"#pe^  
} `/B+  
} z+zEH9.'  
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public void splitterStop() VG50n<m9  
{ ~K(mt0T)  
bStop = true; 2j]uB0  
} $Ny:At  
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} .CW,Td3f!  
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/* @
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**FileAccess.java 2a 7"~z~  
*//文件访问(定位，写) /^X)>1)j  
package NetFox; -%V~1  
import java.io.*; <B @z>V  
PO:sF]5  
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public class FileAccessI implements Serializable{ r!|h3*YA  
Ip *8R]W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ev3,p`zS._  
RandomAccessFile oSavedFile; 7m:TY>{  
long nPos; {7_C|z:'p&  
&7
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public FileAccessI() throws IOException .VohW=D3  
{ |M18/{  
this("",0); =hI;5KF  
} TS=U%)Ik  
;sx4w!Y,  
7E5=Qx  
public FileAccessI(String sName,long nPos) throws IOException \i<7Lk  
{ v(, tu/  
oSavedFile = new RandomAccessFile(sName,"rw"); R+.kwq3CED  
this.nPos = nPos; pA_e{P/  
oSavedFile.seek(nPos); 2|NQ5OA0  
} 6(E
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k(@W z>aCv  
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public synchronized int write(byte[] b,int nStart,int nLen) ]M~7L[  
{ u0qTP]  
int n = -1;
]8<`&~a  
try{ -av=5hm  
oSavedFile.write(b,nStart,nLen); ^}J,;Zhu5  
n = nLen; .;(a;f+{;  
} 19%zcYTe  
catch(IOException e) C3 BoH&  
{ d vo|9>  
e.printStackTrace (); lB!M;2^)X  
} gQ<{NQMzvd  
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wT-Kg=-q  
return n; 0}'/3Q  
} K%u>'W  
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+Z]}ce u"  
} DUg[L
 
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`91Z]zGpU  
/* 7Rc>LI* '  
**SiteInfoBean.java 6:Y2z!MLO  
*/ D'^UZZlI^I  
package NetFox; #Kx @:I  
GXRW"4eF5  
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public class SiteInfoBean { bik lja  
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private String sSiteURL; //Site's URL J5z\e@?.0\  
private String sFilePath; //Saved File's Path >X=VPh8  
private String sFileName; //Saved File's Name vZ^U]h V  
private int nSplitter; //Count of Splited Downloading File 7 ;2>kgf~  
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public SiteInfoBean() *&V"x=ba,  
{//nSplitter的缺省值为5 cyh;1Q
 
//default value of nSplitter is 5 ,-DU)&dF  
this("","","",5); !\'HKk~V  
} xl,6O!aR  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +x~p&,w?  
{ 0oq
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sSiteURL= sURL; vJsg6oH  
sFilePath = sPath; 9hJ  a K  
sFileName = sName; ZkNet>9  
this.nSplitter = nSpiltter; =-qYp0sVP  
$if(n||  
k?1e+ \  
} y'z9Ya  
_94R8?\_V7  
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public String getSSiteURL() o"kL,&  
{ _lC0XDZ  
return sSiteURL; "{c@}~  
} CioS}K  
-"XHN=H  
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public void setSSiteURL(String value) `BaJ >%|  
{ BJ5^-|  
sSiteURL = value; czB),vooz  
} b'vIX< g  
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public String getSFilePath() IYr}%:P)  
{ ;1>V7+/  
return sFilePath; ZmJ<FF4  
} OM`Ws5W}f  
~D`  
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public void setSFilePath(String value) =Wz)(N  
{ A7T(p7pP  
sFilePath = value; uC[F'\Y  
} 0C6T>E7  
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ME.!l6lm\  
public String getSFileName() Qtt3;5m  
{ |D[LU[<C  
return sFileName; Or55_E  
} zy|h1.gd  
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public void setSFileName(String value) =4OV }z=I  
{ }C$D-fH8sW  
sFileName = value; nj-LG!"a  
} ]?NiY:v  
tg9{(_t/W  
Zq:c2/\c}  
public int getNSplitter() lg{M\ +  
{ !LsIHDs
4  
return nSplitter; R~;8v1>K  
} 7&(h_}Z  
tqL2' (=  
,pUB[w\  
public void setNSplitter(int nCount) }*vE/W  
{ +,)Iv_Xl$  
nSplitter = nCount; JZJb&q){  
} R?Ch8mW.!  
} };f^*KZ=0  
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V|/N-3M  
/* ?.c:k;j  
**Utility.java 6w_TL<S  
*/ w BoP&l  
package NetFox; ~b%dBn]n>  
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Fz5eCe\B  
public class Utility { Ci2*5n<  
lbh7`xCR  
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public Utility() MOm+t]vq1  
{ z9v70 q  
vOl3utu7  
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} //bQD>NBO  
Fw^^sB  
//线程睡眠 b27t-p8  
public static void sleep(int nSecond) Rhw+~gd*F  
{ 74hRG~  
try{ 6t'.4SR  
Thread.sleep(nSecond); 6B}V{2  
} G}aM~,v  
catch(Exception e) X<f4X"y  
{ n>)h9q S  
e.printStackTrace (); v7f[$s$m  
} hb>uHUb&  
} m]}EVa_I`/  
pezfB{x?  
//日志 PK&X
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public static void log(String sMsg) ]1I-e2Q-J  
{ OUN"'p%%  
System.err.println(sMsg); yvnvIy  
} !P6?nS  
;Q[E>j?w=  
(v$ i  
public static void log(int sMsg) Qz$Wp*  
{ TZdJq  
System.err.println(sMsg); \7e4t  
} KYq<n& s  
} 0;%\L:,O  
; NO#/  
H)rJ>L  
/* :]LW,Eql  
**TestMethod.java HaF&ooI5+  
*/ v7D0E[)~  
package NetFox; $-\%%n0>6  
 vF'IK,  
~N)(|N  
public class TestMethod { $-(lp0\*  
_6L'}X$)N  
7}(YCZny5  
public TestMethod() =r&i`L{]  
{ ///xx/weblogic60b2_win.exe X3y28 %R   
try{ !"ydl2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); CM t$)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _6]tbni?v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Mv:\
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fileFetch.start(); `*i:z'  
} 8rNf4]5@X(  
catch(Exception e){e.printStackTrace ();} -.
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} Iomx"y]9  
oMNBK/X_  
{<
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public static void main(String[] args) GZmfE`  
{ +hs:W'`%  
new TestMethod(); +KIBbXF7  
} _
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} -@~4:o  
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