http断点续传简单实现（java)

/* _NZ@4+aW  
**SiteFileFetch.java #,NvO!j<4  
*/ L.'}e{ldW  
package NetFox; h2Bz F  
import java.io.*; fV\]L4%  
import java.net.*; DN] v_u+}  
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public class SiteFileFetch extends Thread { {XCf-{a]~  
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SiteInfoBean siteInfoBean = null; //文件信息Bean t18$x"\4k  
long[] nStartPos; //开始位置 `3_lI~=eH  
long[] nEndPos; //结束位置 CH#k(sy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f 2YLk  
long nFileLength; //文件长度 bBc-^  
boolean bFirst = true; //是否第一次取文件 ]9 w76Z  
boolean bStop = false; //停止标志 $ &UZy|9  
File tmpFile; //文件下载的临时信息 z@ 35NZn  
DataOutputStream output; //输出到文件的输出流 MXtkP1A`  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） !wz/cM;  
public SiteFileFetch(SiteInfoBean bean) throws IOException s>n(`?@L  
{ T^.Cc--c  
siteInfoBean = bean; aM3gRp51cj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); BMyzjteS+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S.*~C0"  
if(tmpFile.exists ()) X6e/g{S)  
{ e^1uVN  
bFirst = false;  |a^U]  
read_nPos(); '@nbqM  
} LW)H"6v  
else 9ooY?J  
{ {Qu"%h.Al  
nStartPos = new long[bean.getNSplitter()]; 2}U!:bn(  
nEndPos = new long[bean.getNSplitter()]; KzUlTl0  
} muON>^MbC  
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} V9NTs8LKc  
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public void run() w8Sv*K  
{ \*t~==WB
 
//获得文件长度 Y"g.IK`V  
//分割文件 ,F6=b/eZ  
//实例FileSplitterFetch pc]J[ S?P  
//启动FileSplitterFetch线程 sBX-X$*N  
//等待子线程返回 ^Q<mV*~  
try{ Wi.5Y{  
if(bFirst) t<iEj"5  
{ X;F8_+Np  
nFileLength = getFileSize(); I^\&y(LJF  
if(nFileLength == -1) *XOJnyC_H  
{ &EGqgNl  
System.err.println("File Length is not known!"); q'[}9e`Q  
} (rtY!<|p  
else if(nFileLength == -2) |OO in]5  
{
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System.err.println("File is not access!"); lCd@jB{  
} 5K%SL1N  
else nuQ]8-,  
{ NE2pL@sk  
for(int i=0;i<nStartPos.length;i++) pmvT$;7I  
{ ^"\s eS  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8)*2@-Rp  
} )j l8!O7  
for(int i=0;i<nEndPos.length-1;i++) VSX@e|Nj  
{ DE$q+j0P  
nEndPos = nStartPos[i+1]; g^Yl TB  
} g]~h(mI  
nEndPos[nEndPos.length-1] = nFileLength; "ICC B1N|  
} Fzlozx1y[  
} 75T_Dx(H  
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//启动子线程 VZka}7a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 'wasZ b<^  
for(int i=0;i<nStartPos.length;i++) UB`ToE|Ii  
{ m><w0k?t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N7r_77%m0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `$LWmm#  
nStartPos,nEndPos,i); 6DIZ@oi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g6t"mkMY L  
fileSplitterFetch.start(); /&#XhrT  
} lA(Q@yEW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /'2O.d0}.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Wm~` ~P  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Dn9w@KO  
nEndPos = " + nFileLength); ocbB&  
// fileSplitterFetch[nPos.length-1].start(); uP3_FX: e  
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w>fdQ!RdP  
//等待子线程结束 /PBaIoJE  
//int count = 0; eK_*2=;XRW  
//是否结束while循环 #t8{R~y"gv  
boolean breakWhile = false; n%^ LPD  
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while(!bStop) mbRqJT>@  
{ gF=jf2{YX  
write_nPos(); J&/lx${  
Utility.sleep(500); JG[o"&Sd
 
breakWhile = true; +6$g!S5{  
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for(int i=0;i<nStartPos.length;i++) XKA&XpF  
{ 5vAf7\*  
if(!fileSplitterFetch.bDownOver) WL,&-*JAW  
{ rB~W Iu  
breakWhile = false; j:T/iH!YF  
break; []R? ViG  
} s`j~-P  
} 'TC/vnM  
if(breakWhile) .MW@;  
break; &;,,H
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//count++; .o1^O
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//if(count>4) B&+`)E{KB  
// siteStop(); Yb i%od&  
} OJN2z  
5 8-e^.  
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System.err.println("文件下载结束！"); W6T|iZoV"r  
} "vYE+  
catch(Exception e){e.printStackTrace ();} @l1  
} +x?#DH-  
=
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//获得文件长度 *%w69#D  
public long getFileSize() Ut-B^x)gl  
{ U-k+9f 0  
int nFileLength = -1; UX3BeUi.)  
try{ ;@,Q&B2eM  
URL url = new URL(siteInfoBean.getSSiteURL()); 07Gv*
.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w;}@'GgL  
httpConnection.setRequestProperty("User-Agent","NetFox"); `~eX55W  
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int responseCode=httpConnection.getResponseCode(); 9=w|)p )  
if(responseCode>=400) +uWDP.  
{ "'8KV\/D  
processErrorCode(responseCode); v%k9M{  
return -2; //-2 represent access is error N"/-0(9[  
} 8zLY6@
  
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String sHeader; GLn{s  
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for(int i=1;;i++) id<:p*  
{ BR^7_q4q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7"7rmZ   
//Utility.log(in.readLine()); cYx4~V^  
sHeader=httpConnection.getHeaderFieldKey(i); ^_5L"F]sP  
if(sHeader!=null) ihh4pD27g  
{ /(.6bv  
if(sHeader.equals("Content-Length")) ;!91^Tl  
{ k4qp u=@U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \Gm
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break; %p^.\ch9  
} >e2<!#er|  
} Eca\fkj  
else  $Y=T&O  
break; :+{ ?  
} -U<Upn)2  
} e{;OSk`x  
catch(IOException e){e.printStackTrace ();} |9"p|6G?B  
catch(Exception e){e.printStackTrace ();} 7&`}~$>}>e  
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Utility.log(nFileLength); 6.5T/D*TT  
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return nFileLength; j-CnT)W<  
} Ngr/QL]Q  
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//保存下载信息（文件指针位置） K.G$]H  
private void write_nPos() i>EgG5iJ  
{ uE[(cko  
try{ 2([2Pb3<"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #`GY}-hL!  
output.writeInt(nStartPos.length); 2&+#Vsm`V  
for(int i=0;i<nStartPos.length;i++) h/x
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{ th6+
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// output.writeLong(nPos); ?u4INZ0W  
output.writeLong(fileSplitterFetch.nStartPos); <Dx]b*H  
output.writeLong(fileSplitterFetch.nEndPos); _#$*y  
}  tvXW  
output.close(); #j@71]GI  
} V{|}}b?w?  
catch(IOException e){e.printStackTrace ();} 2tROT][J%  
catch(Exception e){e.printStackTrace ();} eI1GXQ%  
} aNyvNEV3C  
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//读取保存的下载信息（文件指针位置） 0-LpqX  
private void read_nPos() e*+FpW@  
{ =%zLh<3v  
try{ `/Nm 2K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); yq+!czlZ  
int nCount = input.readInt(); Z/^
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nStartPos = new long[nCount]; &a/__c/l  
nEndPos = new long[nCount]; USN8N (  
for(int i=0;i<nStartPos.length;i++) "NRDNqj(  
{ tbnH,*  
nStartPos = input.readLong(); ~gz^Cdh  
nEndPos = input.readLong(); fN"(mW>!  
} 0y&I/2  
input.close(); b':|uu*/  
} }F+zs*S  
catch(IOException e){e.printStackTrace ();} Qu,8t8  
catch(Exception e){e.printStackTrace ();} d:G]1k;z  
} P}.7Mehf  
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private void processErrorCode(int nErrorCode) JQ:Ri  
{ E;21?`x5  
System.err.println("Error Code : " + nErrorCode); ExHKw~y9  
} \5Vde%!$Z  
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//停止文件下载 SWp1|.=Sm  
public void siteStop() zqDR7+]  
{ do uc('@  
bStop = true; x{NX8lN  
for(int i=0;i<nStartPos.length;i++) z} '!eCl  
fileSplitterFetch.splitterStop(); *m%]zj0bo  
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} +n}$pM|NKU  
} nW"q  
//负责部分文件的抓取 y*{Zbz#{  
**FileSplitterFetch.java Rl|4S[  
*/ [i0Hm)Bd3  
package NetFox; k%y9aO  
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import java.io.*; `nUO l  
import java.net.*; rbT)=-(  
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public class FileSplitterFetch extends Thread { jlFk@:y4  
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String sURL; //File URL :S$l"wrh\  
long nStartPos; //File Snippet Start Position a?yMHb{F  
long nEndPos; //File Snippet End Position @|a>&~xX  
int nThreadID; //Thread's ID v#=`%]mL  
boolean bDownOver = false; //Downing is over ~x{.jn  
boolean bStop = false; //Stop identical {_RWVVVe  
FileAccessI fileAccessI = null; //File Access interface -T6(hT\  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `>DP,D)w(  
{ g+-;J+X8  
this.sURL = sURL; eT'
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this.nStartPos = nStart;
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this.nEndPos = nEnd; >=iy2~Fz,  
nThreadID = id; t6c<kIQ:-O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 v){ .Z^_C  
} jkiTj~WE-  
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public void run() Ax oD8|  
{ 6 \B0^
 
while(nStartPos < nEndPos && !bStop) @DW[Z`X
 
{ OL7_'2_z.  
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try{ Ld^GV  
URL url = new URL(sURL); R{,ooxH\J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tweY'x.{  
httpConnection.setRequestProperty("User-Agent","NetFox"); .kTG[)F0b  
String sProperty = "bytes="+nStartPos+"-"; 1>Q{Gs^  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty); ?)'~~@NkH  
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InputStream input = httpConnection.getInputStream(); k7tYa;C  
//logResponseHead(httpConnection); .^)UO  
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byte[] b = new byte[1024]; ,mPnQ?  
int nRead; *M7E#bQ5B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) = sAn,ri  
{ p8wyEHB  
nStartPos += fileAccessI.write(b,0,nRead); 2tayP@$  
//if(nThreadID == 1) \b[9ebME  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @eqeN9e  
} hzI*{  
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Utility.log("Thread " + nThreadID + " is over!"); ozsxXBh-`'  
bDownOver = true; z}SND9-"  
//nPos = fileAccessI.write (b,0,nRead); P
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} 1 4LI5T  
catch(Exception e){e.printStackTrace ();} *zO&N^X.4  
} cYNJhGY  
} ,? E&V_5  
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//打印回应的头信息 U=bEA1*@0  
public void logResponseHead(HttpURLConnection con) eMK+X \  
{ TG n-7 88  
for(int i=1;;i++) VcK}2<8:+~  
{ c41: !u^  
String header=con.getHeaderFieldKey(i); PR<||"03  
if(header!=null) fIoIW&iy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;0ME+]`"3  
Utility.log(header+" : "+con.getHeaderField(header)); !#wdVe_(  
else IB.yU,v  
break; S\y%4}j  
} 5)1+~B  
} ^EVc95|Z  
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public void splitterStop() {|9}+ @5Q1  
{ 4t4olkK3Oa  
bStop = true; C@o%J.9"#  
} 6]Q3Yz^h  
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} dsK&U\ej}  
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/* \(I6_a_{  
**FileAccess.java Np)3+!^1"  
*//文件访问(定位，写) SEKN|YQV/t  
package NetFox; K|W^l\Lt  
import java.io.*; x}fn'iUnm  
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public class FileAccessI implements Serializable{ G,&%VQ3P>  
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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 zH)_vW  
RandomAccessFile oSavedFile; lD;'tqaC  
long nPos; #nyv+x;  
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public FileAccessI() throws IOException 5/ecaAB2  
{ toa-Wa{  
this("",0); zxD,E@lF  
} s #:%x#  
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public FileAccessI(String sName,long nPos) throws IOException L3y5a?G  
{ M\/XP| 7  
oSavedFile = new RandomAccessFile(sName,"rw"); 8?TKN~ja  
this.nPos = nPos; l_FGZ!7  
oSavedFile.seek(nPos); \Z5+$Ij  
} T)u4S[ &  
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public synchronized int write(byte[] b,int nStart,int nLen) (;o*eFC F  
{ ft5DU/%  
int n = -1; ~bU7
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try{ m$UvFP1>u1  
oSavedFile.write(b,nStart,nLen); 9$WJ"]  
n = nLen; 6o}V@UzqV  
} c cG['7  
catch(IOException e) =TcOnQj  
{ Vb6K:ZnF  
e.printStackTrace (); MZm'npRf  
} TnxKR$Hoh  
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return n; 9 pKm*n&  
} f'/ KMe%<  
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} O8RzUg&  
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/* ZxSsR{  
**SiteInfoBean.java Bhuw(KeB  
*/ OhWC}s  
package NetFox; |$w*RI0C  
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public class SiteInfoBean { JLUms  
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private String sSiteURL; //Site's URL v
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private String sFilePath; //Saved File's Path &+;uZ-x  
private String sFileName; //Saved File's Name cIZc:   
private int nSplitter; //Count of Splited Downloading File FLbZ9pX}  
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public SiteInfoBean() x`2p
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{//nSplitter的缺省值为5 [b`$\o'-  
//default value of nSplitter is 5 q
6)N*?  
this("","","",5); ]7<m1Lg  
} N{pa) /  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &q>h*w4O  
{ q!
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sSiteURL= sURL; `QLowna  
sFilePath = sPath; '5WN,Vy8.  
sFileName = sName; w|G~Il  
this.nSplitter = nSpiltter; )kA2vX^=Z  
7 6*hc   
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} }:^XX0:FK  
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public String getSSiteURL() jEE_D +K  
{ Q!)z)-hI  
return sSiteURL; fv|%Ocm  
} 1}DerX6  
:|($,3*  
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public void setSSiteURL(String value) XPVV+.  
{ g^n;IE$B  
sSiteURL = value; ORtg>az\%  
} =F[lg?g  
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public String getSFilePath() ;_bq9x  
{  uE"2kn  
return sFilePath; EFNdiv$wF  
} VVN# $  
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public void setSFilePath(String value) g1dmkX  
{ ZpTi:3>  
sFilePath = value; 3Pa3f >}-  
} ])68wqD  
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public String getSFileName() 7(5]Ry:  
{ yHtGp%j  
return sFileName; 8tC+ lc  
} 5D-BIPn=JV  
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 3:"AFV  
public void setSFileName(String value) kFnUJM$r  
{ (Z'WR  
sFileName = value; c}8 -/P=  
} n4XMN\:g{  
?9,YVylg  
jUZ[`f;  
public int getNSplitter() |y'b217t  
{ u4C1W|x  
return nSplitter; <JJkki  
} d)9PEt
I  
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public void setNSplitter(int nCount) YBeZN98Nt  
{ ju r1!rg%  
nSplitter = nCount; V3%Krn1'  
} h#;?9DP  
} [I_BCf  
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/* J;7s/YH^  
**Utility.java @b8X%0B7  
*/ ul}
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package NetFox; vN'VDvVM  
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|#!eMJ&0  
public class Utility { ./2Z?,  
]+FX$+H/A0  
#fJwC7 4  
public Utility() N.k+AQb  
{ S54gqc1S]  
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} :R{x]sv  
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//线程睡眠 4$qNcMdz  
public static void sleep(int nSecond) $)4GCP  
{ )|MIWgfWN  
try{ ;}n|,g>  
Thread.sleep(nSecond);
'[ @F%  
} Cbazwq  
catch(Exception e) eR(\s_`  
{ sf<Q#ieTxY  
e.printStackTrace (); Ixyvn#ux)  
} Bd/} %4V\@  
} N,h1$)\B#  
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//日志 {_?T:`  
public static void log(String sMsg) qAnA=/k`  
{ 5/zf x  
System.err.println(sMsg); fpI;`s  
} >2FAi.,  
+.XZK3  
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public static void log(int sMsg) #_JA5W+E  
{ Ompi~  
System.err.println(sMsg); "m wl-=  
} >SY2LmV'a  
} hwEZj`9  
(R9QBZP5  
m+;B!46  
/* (rau8  
**TestMethod.java <W=~UUsn  
*/ Q:'qw#P/C  
package NetFox; ]Y?{$M G  
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public class TestMethod { cfrvy^>,  
~| 4U@  
p} t{8j>  
public TestMethod() V=G b>_d  
{ ///xx/weblogic60b2_win.exe pil0,r $D  
try{ r\4*\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Z[DetRc
-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 61ON  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z }FiU
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fileFetch.start(); UrD=|-r`  
}  ;PuyA  
catch(Exception e){e.printStackTrace ();} !D.= 'V  
i}v}K'`  
$.suu^>^w  
} )nf=eU4|  
[ t>}SE  
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public static void main(String[] args) UE}8Rkt  
{ Jdk3) \  
new TestMethod(); bIvJs9L  
} uzzWZ9Tv  
} yv6Zo0s<J  
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