http断点续传简单实现（java)

/* %'"HGZn b  
**SiteFileFetch.java wHtJ_Y  
*/ Zlk,])9Q  
package NetFox; zkh hN"bX  
import java.io.*; v_z..-7Dq+  
import java.net.*; o
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public class SiteFileFetch extends Thread { PEW4J{(W  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^Ti_<<X  
long[] nStartPos; //开始位置 -
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long[] nEndPos; //结束位置 $Ns,ts(ng  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J%\
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long nFileLength; //文件长度 AfRW=&xdT  
boolean bFirst = true; //是否第一次取文件 X&(<G  
boolean bStop = false; //停止标志 pcy<2UV  
File tmpFile; //文件下载的临时信息 X>Al:?`}N  
DataOutputStream output; //输出到文件的输出流 =`Po<7D  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %kh#{*q$  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q(510)  
{ iuC7Y|  
siteInfoBean = bean; u^Nxvx3l0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <vB<`   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }bf=Ntk  
if(tmpFile.exists ()) 22`oFXb'  
{ bmOqeUgB  
bFirst = false; OXHvT/L`  
read_nPos(); C$<"w,  
} VEj$^bpp5s  
else uf)W-Er6~  
{ J7BFk ?=  
nStartPos = new long[bean.getNSplitter()]; ryxYcEM0  
nEndPos = new long[bean.getNSplitter()]; :n'yQ#[rn  
} 0#oBXu  
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} /!GKh5|  
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public void run() .u1X+P7  
{ ]~-*hOcQ4  
//获得文件长度 x\hWyY6J[  
//分割文件 mZ~qG5@/F  
//实例FileSplitterFetch }I]j&\  
//启动FileSplitterFetch线程 kE/`n],1U  
//等待子线程返回 7J9l.cM3  
try{ Hm%g_Mt  
if(bFirst) .'|mY$U~]  
{ |3}5:k  
nFileLength = getFileSize(); 2fl4h<V  
if(nFileLength == -1) Hjs
}  
{ ;%' b;+  
System.err.println("File Length is not known!"); AZwl fdLB  
} TQP+>nS,  
else if(nFileLength == -2) XZS5B~E '  
{ 8|O=/m^]  
System.err.println("File is not access!"); QR<`pmB~y  
} 43zUN  
else <lMg\T?K  
{ *>jjMyn  
for(int i=0;i<nStartPos.length;i++) LA-_3UJx  
{ #HeM,;Xp  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); q-3]jHChh  
} ddsUz1%l  
for(int i=0;i<nEndPos.length-1;i++) v:KX9A.  
{ b'i'GJBQ+$  
nEndPos = nStartPos[i+1]; .~3kGf":  
} `Da+75 f6v  
nEndPos[nEndPos.length-1] = nFileLength; '\`6ot8  
} EYL]TeS  
} 3{"byfO#%  
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//启动子线程 AoBoFZLl3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9
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for(int i=0;i<nStartPos.length;i++) z3a-+NjDm  
{ }e 9!xA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;54(+5pqx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5[C~wvO  
nStartPos,nEndPos,i); n`q2s'Pc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @mf({Q>  
fileSplitterFetch.start(); g\U/&.}DN  
} 79ckLd9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Sk:2+inU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); AoYaVlKG8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o(*F])d
;  
nEndPos = " + nFileLength); "O*x' XhN  
// fileSplitterFetch[nPos.length-1].start(); |; $Bb866/  
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//等待子线程结束 P;vxT}1  
//int count = 0; -Ep!- a  
//是否结束while循环 Z%}4bJ  
boolean breakWhile = false; B0d%c&N${  
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while(!bStop) x4m 5JDC  
{ O:Va&Cyj*  
write_nPos(); kneuV8+(5  
Utility.sleep(500); q$
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breakWhile = true; i9rS6<
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for(int i=0;i<nStartPos.length;i++) p3c"ZPO~z  
{ %r%So_^
  
if(!fileSplitterFetch.bDownOver) )%mg(O8uL  
{ g5+7p@'fV  
breakWhile = false; S]^`woD  
break; { p;shs5  
}  ?CP2AK  
} NjX[;e-u  
if(breakWhile) 2Il8f  
break; AF}gSNX  
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~.^AL}zm_  
//count++; ?cKZ_c  
//if(count>4) VWx]1\  
// siteStop(); %MZP)k,&U  
} ` #
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System.err.println("文件下载结束！"); VfSj E.|  
} e_.Gw"/Yl  
catch(Exception e){e.printStackTrace ();} :^i^0dC  
} p[9s<lEh  
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//获得文件长度 \OQkZ.cU;  
public long getFileSize() A
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{ H4:&%"j7  
int nFileLength = -1; ?>$l  
try{ N\NyXh$  
URL url = new URL(siteInfoBean.getSSiteURL()); aJhxc<"e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B
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httpConnection.setRequestProperty("User-Agent","NetFox"); >|g?wC}V;  
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int responseCode=httpConnection.getResponseCode(); 0|c}p([~  
if(responseCode>=400) f>2MI4nMG  
{ r^0F"9eOL  
processErrorCode(responseCode); +1rkq\{l  
return -2; //-2 represent access is error D:"{g|nW}  
} GIyF81KR 3  
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String sHeader; Kcy@$uF{2  
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for(int i=1;;i++) q_V0+
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{ PLX>-7@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =-"c*^$]  
//Utility.log(in.readLine()); n
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sHeader=httpConnection.getHeaderFieldKey(i); v+G=E2Lh
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if(sHeader!=null) -F@L}|  
{ j$Ab>}g]  
if(sHeader.equals("Content-Length")) E{E0Z9t7&  
{ t)f-mQz)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @WMA}\Cc  
break; k*?I>%^6#T  
} !| #83  
} Jrxz'9qRG  
else &@% $2O.3  
break; {pL+2%`~  
} %}-?bHB1c  
} G2Vv i[c  
catch(IOException e){e.printStackTrace ();} P 43P]M2  
catch(Exception e){e.printStackTrace ();} 0[Ht_qxb  
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Utility.log(nFileLength); mN|r)4{`  
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return nFileLength; zFz10pH  
} oGa^/:6L  
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//保存下载信息（文件指针位置） s{0aBeq  
private void write_nPos() Q GZyL)Q  
{ X5LBEOG  
try{ n_?tN\M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _P?s'HH  
output.writeInt(nStartPos.length); vi.w8>CE  
for(int i=0;i<nStartPos.length;i++) (o5j'2:.  
{ En{`@JsM  
// output.writeLong(nPos); 1rKy@9  
output.writeLong(fileSplitterFetch.nStartPos); M_g?<rK  
output.writeLong(fileSplitterFetch.nEndPos); /D!;u]  
} "]K>j'^Zs<  
output.close(); MN^Aw9U  
} `d7n?|pD  
catch(IOException e){e.printStackTrace ();} Zf$Np50@(  
catch(Exception e){e.printStackTrace ();} $5x ,6[&  
} eI45PMP  
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//读取保存的下载信息（文件指针位置） B"yFS7Rrj  
private void read_nPos() )R`xR,H  
{ [AMAa]^  
try{ I$q]. B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); vM:cWat  
int nCount = input.readInt(); a=cvCf  
nStartPos = new long[nCount]; Ar*^;/  
nEndPos = new long[nCount]; |L2SFB?d=  
for(int i=0;i<nStartPos.length;i++) ?;[w
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{ wLc4Dm*V  
nStartPos = input.readLong(); 1 zw*/dp  
nEndPos = input.readLong(); v~QHMg  
} Xtt?]  
input.close(); wO?{?+I`q  
} "&/-N[is  
catch(IOException e){e.printStackTrace ();} c\a_VRN>r  
catch(Exception e){e.printStackTrace ();} '5&s=M_  
} 8NyJc"T<.  
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private void processErrorCode(int nErrorCode) jCbV,0)^  
{ _SW3_8SuM.  
System.err.println("Error Code : " + nErrorCode); ;rc`OZyE  
} i&{DOI%w  
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2hzsKkrA {  
//停止文件下载 {~Rk2:gx  
public void siteStop() aDO!  
{ '%q$`KDb  
bStop = true; (L^]Lk x)  
for(int i=0;i<nStartPos.length;i++) S$QG.K:<!  
fileSplitterFetch.splitterStop(); i3rH'B-I.  
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|{CfWSB7~@  
} 8Z(Mvq]f&  
} :q#Xq;Wp  
//负责部分文件的抓取 :Nofp&  
**FileSplitterFetch.java phM>.y_  
*/ |*}4 m'c  
package NetFox; 15o9 .   
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import java.io.*; /!c${W!sY  
import java.net.*; j4qJ.i  
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public class FileSplitterFetch extends Thread { ;q*e=[_DF  
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String sURL; //File URL EK4d_L]I  
long nStartPos; //File Snippet Start Position l1f\=G?tmU  
long nEndPos; //File Snippet End Position V4_=<W  
int nThreadID; //Thread's ID P9T}S  
boolean bDownOver = false; //Downing is over 17`1SGZ  
boolean bStop = false; //Stop identical ~]QHk?[wc  
FileAccessI fileAccessI = null; //File Access interface A!h`]%0B  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v%q0OX>9X"  
{ <yd{tD$A*  
this.sURL = sURL; 3\XU_Xs(]  
this.nStartPos = nStart; *s:(j
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this.nEndPos = nEnd; r-Pkfy(  
nThreadID = id; H'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3f,hw5R  
} /
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public void run() H!$o$}A  
{ #w' k
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while(nStartPos < nEndPos && !bStop) [Al&  
{ INJEsz  
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try{ `hQ5VJo  
URL url = new URL(sURL); Fvbh\m ~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4rLL[??  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]@phF _  
String sProperty = "bytes="+nStartPos+"-"; sG F aL  
httpConnection.setRequestProperty("RANGE",sProperty); _no*k?o*  
Utility.log(sProperty); ?vbvBu{a  
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InputStream input = httpConnection.getInputStream(); c}2jmwq  
//logResponseHead(httpConnection); eQ]~dA8>  
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byte[] b = new byte[1024]; $w`=z<2yo1  
int nRead; =`H@%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'F9jq  
{ tM'P m  
nStartPos += fileAccessI.write(b,0,nRead); $xPaYf  
//if(nThreadID == 1) H" 3fT0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \RC'XKQ*n  
} 5Ou`z5S\k  
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Utility.log("Thread " + nThreadID + " is over!"); 8~@c)Z;  
bDownOver = true; Na]:_K5Dp  
//nPos = fileAccessI.write (b,0,nRead); ;z$(nhJ  
} hvsWs.;L'  
catch(Exception e){e.printStackTrace ();} a6)BqlJ  
} GkQpELO:  
} ?iWi  
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@~"h62=] -  
//打印回应的头信息 j~[z2tV  
public void logResponseHead(HttpURLConnection con) |}Nn!Sj>#;  
{ #."-#"0  
for(int i=1;;i++) CTq&-l:f  
{ Nh_Mz;ITuu  
String header=con.getHeaderFieldKey(i); ?kbiMs1;u  
if(header!=null) c7x~{V8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4R1<nZ"e~  
Utility.log(header+" : "+con.getHeaderField(header)); vunHNHltW0  
else jtW!"TOY  
break; S.-TOE  
} '!
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} #W4dkCd(pF  
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public void splitterStop() gG(fQ 89U"  
{ [\v
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bStop = true; "Q@ronP(~  
} -g*4(w  
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} EyJJ0  
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\fz<.l]  
/* A$Hfr8w1u  
**FileAccess.java R{
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*//文件访问(定位，写) Q ayPo]O  
package NetFox; jaII r06  
import java.io.*; OEA&~4&{7  
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public class FileAccessI implements Serializable{ &=] ~0$  
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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 IP xiV]c  
RandomAccessFile oSavedFile; r*2+xDoEi  
long nPos; )rxX+k+b/  
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public FileAccessI() throws IOException [+T.at  
{ 4xjPiHd<  
this("",0); h-q3U%R4}@  
} [9evz}X  
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public FileAccessI(String sName,long nPos) throws IOException EE&K0<?T|:  
{ '3/4?wi  
oSavedFile = new RandomAccessFile(sName,"rw"); %*A0#F  
this.nPos = nPos; t5\-v_mG=&  
oSavedFile.seek(nPos); 46_xyz3+  
} &Cr:6W@A  
=_JjmTy;a  
mqD}BOif  
public synchronized int write(byte[] b,int nStart,int nLen) 2=,lcWr  
{ 5Dm.K?l;  
int n = -1; >%}C^gu)  
try{ 6m*QX+  
oSavedFile.write(b,nStart,nLen); ]b2pG'  
n = nLen; ^a0um/+M}  
} EN<F# Y3E  
catch(IOException e) JVvs-bK5
 
{ AVlhNIr  
e.printStackTrace (); 4VJ-,Z  
} D=j-!{zB  
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return n; x9UX!Z5*>  
} LiN$ pwm  
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} Z]>O+  
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/* V\ZGd+?  
**SiteInfoBean.java BTqS'NuT  
*/ ! `  
package NetFox; ] {RDVA=]  
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public class SiteInfoBean { Yg]-wQrH  
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private String sSiteURL; //Site's URL jFQQ`O V  
private String sFilePath; //Saved File's Path 2V- 16Q'%  
private String sFileName; //Saved File's Name jwc
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private int nSplitter; //Count of Splited Downloading File E:UW#S%A f  
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7  
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public SiteInfoBean() x|/|jzJSX  
{//nSplitter的缺省值为5 >N^Jj:~l  
//default value of nSplitter is 5 $Xv*,Bq  
this("","","",5); nsu@h  
} Xb|:vr\v  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  ~^NtO  
{ u1J0$  
sSiteURL= sURL; Ec!"O3%!M^  
sFilePath = sPath; 8bTn^!1  
sFileName = sName; RuLi,'u  
this.nSplitter = nSpiltter; ity & v9  
>{q]&}^U  
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} faEt6  
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public String getSSiteURL() ;v}GJ
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{ j$M h+5  
return sSiteURL; q}i
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} F|SXn\  
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dm  
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public void setSSiteURL(String value) 3
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{ 3]5^r}  
sSiteURL = value; #3i3G(mQ  
} [;n9:Qxf  
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public String getSFilePath() ]AINKUI0  
{ O*hDbM2QQw  
return sFilePath; S]}nm  
} -$pzl,^ h  
aB_F9;IR  
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public void setSFilePath(String value) @:oXN]+ _  
{ Ot4 Z{mA  
sFilePath = value; b)6D_Az7c  
} %R}qg6dL  
"M<8UE\n  
-R|,9o^  
public String getSFileName() TJ10s%,V  
{ 8H%;WU9-  
return sFileName; M1k{t%M+S  
} Kr?TxhUHd  
5#HW2"7  
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public void setSFileName(String value) Gj1&tjK  
{ 0\X\izQ5  
sFileName = value; !S$:*5=&  
} 8v:T.o;<  
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S ^!n45l  
public int getNSplitter() DBo%fYst  
{ |)IlMG  
return nSplitter; dH;8mb|#'  
} ~uj#4>3T  
$
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]Z>}6!  
public void setNSplitter(int nCount) Yk'XGr)  
{ y`L>wq,KU  
nSplitter = nCount; 8EZ$g<}  
} |tKsgj  
} Xe3U`P7(  
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/* S(k3 `;K  
**Utility.java .yMEIUm  
*/ NpE*fR')  
package NetFox; 4zXFuTr($  
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public class Utility { "H=6j)Cb  
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public Utility() C(eTR1  
{ a4mn*,  
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} ny]?I
  
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//线程睡眠 OTvPUkp*
 
public static void sleep(int nSecond) 1D7nkAy  
{ WltQ63u  
try{ xzdf^Ce  
Thread.sleep(nSecond); GF"hx`zyJ  
} ]{sU&GqBLe  
catch(Exception e) Ryl:a\  
{ "SNn^p59k  
e.printStackTrace (); |'e^QpU5  
} Q{O+  
} Giid~e33  
Z]A{ d[  
//日志 8f_l}k$Eg  
public static void log(String sMsg) 1gE
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{ Bj+S"yS  
System.err.println(sMsg); #QS`_TlKk  
} Q1
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]vz%iv_  
public static void log(int sMsg) a1g,@0s  
{ gI&#o@Pm  
System.err.println(sMsg); e+=y*OmQ  
} d8DV[{^  
} f- K+]aZ)  
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/* 0
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**TestMethod.java %p Ynnfr  
*/ SUMrFd~  
package NetFox; o5u3Fjz3  
|-b#9JQ[A  
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public class TestMethod { [xbSYu,&  
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1m'k|Ka  
public TestMethod() ,[N%Q#  
{ ///xx/weblogic60b2_win.exe kC:uG0sW  
try{ nB_?ckj,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C>]0YO k2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xI{)6t$`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *zaQx+L  
fileFetch.start(); p99]  
} <3oWEm  
catch(Exception e){e.printStackTrace ();} I~[F|d>  
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{IjF+@I  
} bc7/V#W  
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public static void main(String[] args) ]dF ,:8  
{ 9G9t" {  
new TestMethod(); ?Lx24*5%  
} .zr-:L5{  
} d}OTO10  
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