http断点续传简单实现（java)

/* 7'uuc]\5>  
**SiteFileFetch.java ,rx?Ig}kz  
*/ |fkz=*rn  
package NetFox; eS{lr4-]  
import java.io.*; E8j>Toz  
import java.net.*; {{w5F2b((%  
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public class SiteFileFetch extends Thread { :t+XW`eQR:  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ")T;3/c  
long[] nStartPos; //开始位置 wGD
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long[] nEndPos; //结束位置 ^u`1W^>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 RGvfy/T  
long nFileLength; //文件长度 Q{1Q w'+@  
boolean bFirst = true; //是否第一次取文件 w'E&w)Z]  
boolean bStop = false; //停止标志 ".Z|zt6C  
File tmpFile; //文件下载的临时信息 l0N~mes  
DataOutputStream output; //输出到文件的输出流 _{0'3tI7  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <WhdQKFf-  
public SiteFileFetch(SiteInfoBean bean) throws IOException I(!i"b9  
{ b8Gu<Q1k  
siteInfoBean = bean; =E?kxf[X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IJ >qs8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); LCKCg[D  
if(tmpFile.exists ()) SbS*z:  
{ !c+,OU[  
bFirst = false; 03Czx`  
read_nPos(); @$o.Z;83`r  
} {}>s0B  
else #pDWwnP[rt  
{ Yl}'hRp  
nStartPos = new long[bean.getNSplitter()]; 62BT3/~  
nEndPos = new long[bean.getNSplitter()]; 2ZUI~:U Z  
} n$]78\C  
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} E
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:
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public void run() o_=t9\:  
{ Ss>ez8q  
//获得文件长度 vlW521  
//分割文件 ITpo:"X g  
//实例FileSplitterFetch )T2V<3l  
//启动FileSplitterFetch线程 w4I&SLm-b  
//等待子线程返回 \.!+'2!m  
try{ e3T&KyPm?+  
if(bFirst) N>a. dYXr  
{ ?x
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nFileLength = getFileSize(); gl.uDO%.  
if(nFileLength == -1) ::goqajV  
{  S(*u_  
System.err.println("File Length is not known!"); YF)uAJAk  
}
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else if(nFileLength == -2) $qndG,([F  
{ Vc2(R^  
System.err.println("File is not access!"); K14F
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} u?Pec:3%  
else 3:H[S_q  
{ S=f:-?N|  
for(int i=0;i<nStartPos.length;i++) r1pj-   
{ {Sl#z}@s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w^BF.Nu  
} ML:Zm~A1U  
for(int i=0;i<nEndPos.length-1;i++) Ufw_GYxan  
{ Z|t`}lK  
nEndPos = nStartPos[i+1]; ([g[\c,H  
} Sm7O%V8{p  
nEndPos[nEndPos.length-1] = nFileLength; E}qW'  
} d1[;~)  
} U!y GZEU"[  
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//启动子线程 MP LgE.n  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; FqWW[Bgd  
for(int i=0;i<nStartPos.length;i++) Jam&Rj,  
{ }Mv$Up  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u)X]]6
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +Oxw?`I$  
nStartPos,nEndPos,i); 0gevn  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -!bf
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fileSplitterFetch.start(); ScCp88KpFI  
} VoG_'P  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v?Ds|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [}+h86:y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y| dw>qO  
nEndPos = " + nFileLength); fo$s9g^<  
// fileSplitterFetch[nPos.length-1].start(); `<#Ufi*c  
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" J4?Sb<  
//等待子线程结束 +sY8<y@%  
//int count = 0; z JBcz,  
//是否结束while循环 4{v?<x8  
boolean breakWhile = false; 6?`3zdOeO  
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while(!bStop) Jc=~BT_G  
{ vB?(|  
write_nPos(); v?@=WG  
Utility.sleep(500); Zws[C  
breakWhile = true;  8MZ:=  
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for(int i=0;i<nStartPos.length;i++) a#pM9n~a  
{ -J& b~t@  
if(!fileSplitterFetch.bDownOver) Dug{)h_2  
{ AqZ()p*z  
breakWhile = false; 4 (>8tP\Y  
break; hy}n&h  
} n/ CP2A  
} V\m51H1mqo  
if(breakWhile) dxa[9>V  
break; SB)Hz8<  
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//count++; Io*mFa?  
//if(count>4) ~a ]R7X7  
// siteStop();
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} O<\h_   
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System.err.println("文件下载结束！"); K&IHt?vh!  
} gw^X-  
catch(Exception e){e.printStackTrace ();} E%&E<<nhZ  
} rvUJK,oE  
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//获得文件长度 ]vQU(@+I  
public long getFileSize() /R
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{ (GJX[$@  
int nFileLength = -1; 6DxT(VU}  
try{ pKzrdw-!  
URL url = new URL(siteInfoBean.getSSiteURL()); [ApAd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 08W^  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5uAUi=XA>S  
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1 F+$\fLr  
int responseCode=httpConnection.getResponseCode(); k%K\~U8"  
if(responseCode>=400) UNhM:!A  
{ W*Gp0pX  
processErrorCode(responseCode); bBp('oEJ
u  
return -2; //-2 represent access is error m^%Xl@V:c-  
} z#Cgd-^7.#  
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String sHeader; F!MxC  
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for(int i=1;;i++) +V,Ld&r  
{ pP^"p"<s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <=g
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//Utility.log(in.readLine()); MngfXm  
sHeader=httpConnection.getHeaderFieldKey(i); r.10b]b  
if(sHeader!=null) 3F\UEpQ  
{ w@$_2t  
if(sHeader.equals("Content-Length")) x)prI6YMv\  
{ &?0hj@kd~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); be(p13&od  
break; |>Wi5h{6X  
} x-Fl|kwX.5  
} QV*W#K\7q  
else *OR(8;  
break; mF@DO$  
} U\`yLsKvH`  
} q,fk@GI'2  
catch(IOException e){e.printStackTrace ();} =G-u "QJ6  
catch(Exception e){e.printStackTrace ();} E
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Utility.log(nFileLength); #M=d)}[  
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return nFileLength; E?^A+)<"  
} nk+*M9r|I  
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//保存下载信息（文件指针位置） DOGg=`XK1  
private void write_nPos() ~glFB`?[  
{ 8+U':xR  
try{ Oo`b#!L  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ealh>Y  
output.writeInt(nStartPos.length); [0-zJy|,  
for(int i=0;i<nStartPos.length;i++) gA~faje  
{ <#5`%sa '  
// output.writeLong(nPos); hP]zC1s  
output.writeLong(fileSplitterFetch.nStartPos); &xjeZh4-  
output.writeLong(fileSplitterFetch.nEndPos); &Vi0.o  
} !e(ZEV g  
output.close(); <B=!ZC=n  
} ey3;rY1  
catch(IOException e){e.printStackTrace ();} ~zA{=|I2  
catch(Exception e){e.printStackTrace ();} G##^xFx  
} ;WpPdR2  
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//读取保存的下载信息（文件指针位置） ICI8xP}a?  
private void read_nPos() *S>,5R0k  
{ Ea2&7  
try{ dL!K''24{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *
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int nCount = input.readInt(); wfc[B;K\  
nStartPos = new long[nCount]; n\D3EP<s  
nEndPos = new long[nCount]; D:Y`{{  
for(int i=0;i<nStartPos.length;i++) l5d> YTK+5  
{
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nStartPos = input.readLong(); TAn.5 wH9t  
nEndPos = input.readLong(); !WReThq  
} ^Wz3 q-^  
input.close(); u:7=Yy :  
} _ Oe|ZQ  
catch(IOException e){e.printStackTrace ();} gDJ@s   
catch(Exception e){e.printStackTrace ();}
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} G$HLta  
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private void processErrorCode(int nErrorCode) *>XY' -;2e  
{ r
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System.err.println("Error Code : " + nErrorCode); G ]mX+?  
}  p3r1lUw  
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8  
//停止文件下载 oNV(C'A  
public void siteStop() wOp# mT  
{ .DkDMg1US  
bStop = true; L5*,l`lET  
for(int i=0;i<nStartPos.length;i++) 8E!I9z  
fileSplitterFetch.splitterStop(); TAt9+\'  
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} ]Zf@NY  
} .W+ F<]r  
//负责部分文件的抓取 R.)U<`||  
**FileSplitterFetch.java !jDqRXi(  
*/ i#~1|2  
package NetFox; 9N'um%J3%s  
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import java.io.*; cMEM}Qh T  
import java.net.*; TIa`cU`  
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public class FileSplitterFetch extends Thread { Q nqU!6k@  
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String sURL; //File URL s `r tr  
long nStartPos; //File Snippet Start Position OQA3~\Vu  
long nEndPos; //File Snippet End Position N2_=^s7  
int nThreadID; //Thread's ID VM3H&$d(h  
boolean bDownOver = false; //Downing is over NOa.K)^k  
boolean bStop = false; //Stop identical NB&u^8b  
FileAccessI fileAccessI = null; //File Access interface | We @p  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException H\3CvFm  
{ m(3bO[u1  
this.sURL = sURL; @$79$:q N  
this.nStartPos = nStart; (t9qwSS8z  
this.nEndPos = nEnd; Tj{!Fx^H  
nThreadID = id; 'ej{B0rE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Sg<''pUh  
} lm&C!{K  
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public void run() ]~(Ipz2NP  
{ ZH%[wQ~4  
while(nStartPos < nEndPos && !bStop) t MB;GIb#  
{ 8}Y( @ %4  
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m[{*an\  
try{ ,7M9f  
URL url = new URL(sURL); 1{"fmV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F ,{nG[PL  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3@}HdLmN|  
String sProperty = "bytes="+nStartPos+"-"; %'* |N[  
httpConnection.setRequestProperty("RANGE",sProperty); YS{  
Utility.log(sProperty); ,oP-:q!PC  
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InputStream input = httpConnection.getInputStream(); 5Kv=;o=U  
//logResponseHead(httpConnection); wrn[q{dX  
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byte[] b = new byte[1024]; [-$&pB>w8'  
int nRead; $Y,]D*|"K  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;lA
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{
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nStartPos += fileAccessI.write(b,0,nRead); fD\h5`-  
//if(nThreadID == 1) df1* [  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FZA8@J|Q4  
} XpH[SRUx  
=-`+4zB\  
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Utility.log("Thread " + nThreadID + " is over!"); 8`VMdo9  
bDownOver = true; ]hvB-R16f  
//nPos = fileAccessI.write (b,0,nRead); >uOc#+5M.  
} v&XG4 &  
catch(Exception e){e.printStackTrace ();} 4g1u9Sc0  
} [1nI%/</>  
} fJE k
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//打印回应的头信息 v,|
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public void logResponseHead(HttpURLConnection con) FcW ?([l  
{ Vn/6D[}Tu  
for(int i=1;;i++) Gcs+@7!b  
{ Ya9uu@F  
String header=con.getHeaderFieldKey(i); (rwbF  
if(header!=null) xJ
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8
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Utility.log(header+" : "+con.getHeaderField(header)); ]K9x<@!  
else ;*Z w}51  
break; ?>o39|M_w  
} LOida#R  
} ^m1Rw|  
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c>UITM=!I  
public void splitterStop() L8j,?u#  
{ C}1(@$  
bStop = true; 0KDDAkR5R  
} #Y18z5vo  
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} ldX]A#d.  
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/* <m(nZ'Zqz2  
**FileAccess.java r\3In-(AT  
*//文件访问(定位，写) huTJ a2  
package NetFox; <aHK{*'3  
import java.io.*; ;c>Yr?^  
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5;^8wh(  
public class FileAccessI implements Serializable{ 84knoC  
.M! (|KE4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d;;=s=j  
RandomAccessFile oSavedFile; )nJ>kbO~8  
long nPos; @P.l8|w  
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public FileAccessI() throws IOException ~b7Nzzfo  
{ s=q+3NTv  
this("",0); m|7g{vHVV  
} AjlG_F  
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public FileAccessI(String sName,long nPos) throws IOException 9/%|#b-z  
{ OKU P  
oSavedFile = new RandomAccessFile(sName,"rw"); SA&wW\Ym]  
this.nPos = nPos; n)=&=Uj`f  
oSavedFile.seek(nPos); \D[BRE+  
} vB Jva8;Q  
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public synchronized int write(byte[] b,int nStart,int nLen) AHA*yC  
{ .6"7Xxe]<  
int n = -1; an7N<-?
 
try{ RTU:J67E  
oSavedFile.write(b,nStart,nLen); S;c=6@"  
n = nLen; {l6]O  
} W[?B@sdSZ  
catch(IOException e) )5t_tP
v  
{ Qpc{7#bp  
e.printStackTrace (); xl9l>k6,  
} lxd<^R3i#^  
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return n; hB.dqv]^  
} j;y|Ys)I  
Ya. $x~  
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} ?~K2&eo  
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/* ]@P*&FRcZ  
**SiteInfoBean.java DEs?xl]zO  
*/ /{U{smtdFl  
package NetFox; `WB|h)Y  
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public class SiteInfoBean { m\>x_:sE  
x -!FS h8q  
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private String sSiteURL; //Site's URL fkG8,=  
private String sFilePath; //Saved File's Path ,J^Op   
private String sFileName; //Saved File's Name /LD*8 a  
private int nSplitter; //Count of Splited Downloading File <D^x6{}  
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public SiteInfoBean() Q.\>+4]1&&  
{//nSplitter的缺省值为5 QD<4(@c5|  
//default value of nSplitter is 5 ayD
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this("","","",5); [GuDMl3hC  
} \f  LBw0  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =FbfV*K9  
{ E;4a(o]{t  
sSiteURL= sURL; RFC;1+Jn  
sFilePath = sPath; fz&}N`n  
sFileName = sName; ;x#>J +QlG  
this.nSplitter = nSpiltter; A-io-P7qyj  
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} JK(&E{80  
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6S<$7=$=  
public String getSSiteURL() 6
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{ Kv]6 b2HT  
return sSiteURL; +XE21hb   
} 6!nb)auVi  
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public void setSSiteURL(String value) Mb>XM7}PU  
{ +7^Ul6BB#K  
sSiteURL = value;
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}  M9K).P=  
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public String getSFilePath() iV&#5I  
{ /v{[Z&z  
return sFilePath; *eP4dGe&  
} o zYI/b^  
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public void setSFilePath(String value) yLx.*I^6  
{ [q&J"dt  
sFilePath = value; q,DX{:  
} dX*>?a  
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public String getSFileName() \bOjb\ w$  
{ fhmr*E'J  
return sFileName; -z$0S%2?  
} l5[xJH  
".%LBs~$  
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public void setSFileName(String value) %7#Zb'  
{ {*<C!Qg  
sFileName = value;  >Gu0&  
} ,NEs{! T  
3kCbD=yF  
Y14R"*t~  
public int getNSplitter() {1aAm+  
{ #!jRY!2Vt  
return nSplitter; >!1f`  
} s8[9YfuW  
4C%>/*%8>  
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public void setNSplitter(int nCount) w<Cmzkf  
{ rcx;3Vne  
nSplitter = nCount; S I7B6c  
} P|4E1O  
} ]$*{<
  
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/* 7omGg~!k(  
**Utility.java i4n b#  
*/ Oq,
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package NetFox; sjI[Vq  
/K) b0QX  
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public class Utility { d7J[.^\  
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public Utility() H?j-=Zka  
{ 9>3Ltnn0  
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} LGROEn<*d  
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//线程睡眠 )O@^H  
public static void sleep(int nSecond) s}#[*WOc  
{ 2ZbY|8X$r  
try{ 9c{%m4
  
Thread.sleep(nSecond); 1qj%a%R  
} ,{?bM  
catch(Exception e) ]ZGvRA&  
{ 0ITA3v8{  
e.printStackTrace (); E#$_uZ4  
} pq?[wp"  
} n,jE#Z.D  
./nYXREO|  
//日志 udD*E~1q  
public static void log(String sMsg) 7G[ GHc>  
{ #)mkD4  
System.err.println(sMsg); [gkRXP[DGs  
} ru/zLj:  
I^O:5x>[l  
"1!.^<V*  
public static void log(int sMsg) Da8$Is;n  
{ @@/'b'  
System.err.println(sMsg); J)8pqa   
} Ag#5.,B-  
} KPjqw{gR_R  
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e0N=2i?I#z  
/* #4_O;]{'  
**TestMethod.java 7tl)4A6  
*/ k]$E8[.t  
package NetFox; 9hR:y.  
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r,.95@  
public class TestMethod { J;=aIiN]R  
av; (b3Lq  
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public TestMethod() )/WA)fWkT  
{ ///xx/weblogic60b2_win.exe _UBJPb@=U  
try{ ^dUfTG9{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {`K]sa7`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); DtF![0w/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m{lRFKx>s  
fileFetch.start(); h"BhTx7E}  
} )1Ma~8Y%r  
catch(Exception e){e.printStackTrace ();} TFJ{fLG  
oj^5G ]_<  
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} X[~f:E[1J  
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@8M'<tr<z  
public static void main(String[] args) |P. =  
{ n$hqNsM  
new TestMethod(); HV*:<2P%D  
} vN0L(B  
} a(x.{}uG,  
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