http断点续传简单实现（java)

/* OF!n}.O(  
**SiteFileFetch.java W[73q>'  
*/ 7Uh/Gl  
package NetFox; D;DI8.4`N  
import java.io.*; dFnu&u"  
import java.net.*; P>*`<$FR  
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public class SiteFileFetch extends Thread { ^p\n/#B  
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SiteInfoBean siteInfoBean = null; //文件信息Bean K!!#";Eo  
long[] nStartPos; //开始位置 ;@[ax{ J  
long[] nEndPos; //结束位置 emS7q|^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >~G _'~_f  
long nFileLength; //文件长度 %i.;~>  
boolean bFirst = true; //是否第一次取文件 wF['oUwHH  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 \!r,>P
 
DataOutputStream output; //输出到文件的输出流 c 9zMI  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） rPJbbV",+^  
public SiteFileFetch(SiteInfoBean bean) throws IOException nqib`U@"  
{ ~_4$|WKl  
siteInfoBean = bean; {'f=*vMI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MrS~u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l;;"v) C8  
if(tmpFile.exists ()) r@H7J 5<Y-  
{ ;J?zD9  
bFirst = false; .+`Z:{:BC&  
read_nPos(); 1jj.oa]  
} +"[}gss!@  
else gG,gL9o  
{ SRyot:l   
nStartPos = new long[bean.getNSplitter()]; ]y/!GFQ  
nEndPos = new long[bean.getNSplitter()]; fq[,9lK  
} 9m2Yrj93  
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} 9%bqY9NFd  
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public void run() +{{'3=x9  
{ *JY2vq  
//获得文件长度 Q-$EBNz  
//分割文件 f`,isy[  
//实例FileSplitterFetch FZJ sZeO  
//启动FileSplitterFetch线程 "]1|%j  
//等待子线程返回 2c8e:Xgv  
try{ .h>te
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if(bFirst) 7?~*F7F  
{ 4-\gha  
nFileLength = getFileSize(); /Os;,g  
if(nFileLength == -1) @:G#[>nKe  
{ L]Dl}z  
System.err.println("File Length is not known!"); soB5sFt&]  
} 9uA2M!~i2  
else if(nFileLength == -2) Zd[6-/-:  
{ 4.i< `'  
System.err.println("File is not access!"); WH0$v#8`v  
} 3Qoa?*  
else *bTR0U  
{ `1U?^9Nf  
for(int i=0;i<nStartPos.length;i++) DTSK*a`  
{ CXhE+oS5z'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a*KJjl?k  
} pksF|VS  
for(int i=0;i<nEndPos.length-1;i++) dfA4OZ&  
{ c=\H&x3X  
nEndPos = nStartPos[i+1]; .VfBwTh7q8  
} gye'_AR?k  
nEndPos[nEndPos.length-1] = nFileLength; \y0uGnmCj  
} ]tDuCZA  
} ?Y#x`DMh  
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//启动子线程 Cdbh7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; LuUfdzH  
for(int i=0;i<nStartPos.length;i++) KZt4 dr  
{ }6^d/nE*T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Oxhc!9F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), dQH9NsV7g  
nStartPos,nEndPos,i); P[bj{lo  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XCU>b[Cj,  
fileSplitterFetch.start(); #[aHKq:?b  
} I^yInrRh5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uf&Ke k,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K trR+:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fp2.2 @[  
nEndPos = " + nFileLength); I2<t?c:Pn<  
// fileSplitterFetch[nPos.length-1].start(); 0!!z'm3  
vd}Y$X  
(}NKW  
//等待子线程结束 r1QLSD]i6  
//int count = 0; 8 ,<F102(  
//是否结束while循环 ~xaPq=AH  
boolean breakWhile = false; 1 n<7YO7}  
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while(!bStop) (*\*7dIo  
{ v08Xe*gNU  
write_nPos(); 2W 9N-t21  
Utility.sleep(500); xxC2F:Q?U  
breakWhile = true; n%Gk {h5  
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for(int i=0;i<nStartPos.length;i++) 
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{ [N4#R  
if(!fileSplitterFetch.bDownOver) ^;]Q,*Q  
{ ct#3*]  
breakWhile = false; LU7d\Ch  
break; z7'C;I  
} 1'{A,!  
} BVk&TGa;[$  
if(breakWhile) 8LM 91  
break; /MUa b*h  
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//count++; +Tug.[A  
//if(count>4) pN
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// siteStop(); pAd 8-a  
} Xitsbf=Gg  
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System.err.println("文件下载结束！"); eURj'8o),  
} CHPu$eu  
catch(Exception e){e.printStackTrace ();} CVyE5w  
} OL
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//获得文件长度 3Bk_
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public long getFileSize() @L ,hA v^  
{ 4)XZ'~|  
int nFileLength = -1; 2!+saf^-,  
try{ m$X0O_*A  
URL url = new URL(siteInfoBean.getSSiteURL()); qz .{[l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +7]]=e<[E  
httpConnection.setRequestProperty("User-Agent","NetFox"); g~i%*u,Y<  
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,{  
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int responseCode=httpConnection.getResponseCode(); o2C{V1nB  
if(responseCode>=400) sAG#M\A6  
{ )Kw Gb&l&  
processErrorCode(responseCode); LyB &u()  
return -2; //-2 represent access is error ^t{2k[@  
} .0b$mSV[  
 KDODUohC  
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String sHeader; 2MapB*  
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for(int i=1;;i++) U)n+j}vi  
{ 1>BY:xZr  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^mA^7jB  
//Utility.log(in.readLine()); np#RBy  
sHeader=httpConnection.getHeaderFieldKey(i); C;C= g1I}  
if(sHeader!=null) TZ2-%k#  
{ muc>4!Q  
if(sHeader.equals("Content-Length")) Pq@%MF]5  
{ ~RRp5x _  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ca},tov&  
break; Xj^Hy"HC^~  
} '8$*gIQ8  
} Y%B:IeF}  
else W".: 1ov#B  
break; bvK fxAih  
} d 18>0R  
} };z[x2l^  
catch(IOException e){e.printStackTrace ();} b;X|[tB  
catch(Exception e){e.printStackTrace ();} o'8`>rb  
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Utility.log(nFileLength); X?'v FC  
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return nFileLength; ,'E+f%  
} #H;yXsR`  
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//保存下载信息（文件指针位置） 7vRFF@eq}  
private void write_nPos() t3dvHU&Z:  
{ v
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try{ g=T !fF=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <]jKpJ{3N  
output.writeInt(nStartPos.length); #@*;Y(9Ol  
for(int i=0;i<nStartPos.length;i++)  9z9EK'g  
{ w[bhm$SX]B  
// output.writeLong(nPos); c%N8|!e  
output.writeLong(fileSplitterFetch.nStartPos); P}AfXgr  
output.writeLong(fileSplitterFetch.nEndPos); QR+{Yp  
} {g%F 3-  
output.close(); Dp5hr8bT  
} _qZ?|;o^  
catch(IOException e){e.printStackTrace ();} HFr#Ql>g  
catch(Exception e){e.printStackTrace ();} -/k;VT|  
} ]~!jf  
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//读取保存的下载信息（文件指针位置） +EtL+Y(U  
private void read_nPos() 0gs0[@  
{ u0)~Im,X  
try{ zO)>(E?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); YL$#6d  
int nCount = input.readInt(); 2Op\`Ht&  
nStartPos = new long[nCount]; wcdD i[E>i  
nEndPos = new long[nCount]; sC/5N  
for(int i=0;i<nStartPos.length;i++) 1h"CjOp,7  
{ u9.x31^  
nStartPos = input.readLong(); :2qUel\PEC  
nEndPos = input.readLong(); Zi0B$3iOb  
} :KJG3j?   
input.close(); B_^ ~5_0:  
} %(
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catch(IOException e){e.printStackTrace ();} ~(BvIzzD  
catch(Exception e){e.printStackTrace ();} ]7*Z'E  
} !yo/ F&6  
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private void processErrorCode(int nErrorCode) dFu<h   
{ ~s :Ml  
System.err.println("Error Code : " + nErrorCode); ~F</s.  
} 'pJ46"D@m  
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//停止文件下载 X"S-f;b#  
public void siteStop() jK[~dY
  
{ %|6t\[gn  
bStop = true; &I&:  
for(int i=0;i<nStartPos.length;i++) IsaL+elq|  
fileSplitterFetch.splitterStop(); 5B
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} @Gh?|d7bD  
} b V)mO@N~w  
//负责部分文件的抓取 xHA6  
**FileSplitterFetch.java b"au9:F4@7  
*/ w4:  
package NetFox; HG1)q\Xd  
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import java.io.*; .=j]PckJO  
import java.net.*; y%y F34  
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public class FileSplitterFetch extends Thread { w3l+BUn:X  
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String sURL; //File URL D[m+=-  
long nStartPos; //File Snippet Start Position P,$|.pd'  
long nEndPos; //File Snippet End Position A]z~Dw3  
int nThreadID; //Thread's ID {Hv/|.),hu  
boolean bDownOver = false; //Downing is over Px!M^ T!Pi  
boolean bStop = false; //Stop identical D!K){E  
FileAccessI fileAccessI = null; //File Access interface ST#OO!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )zFPf]gz  
{ :YZqrcr}  
this.sURL = sURL; j^t#>tZS  
this.nStartPos = nStart; Mw0Kg9M  
this.nEndPos = nEnd; z,6X{=  
nThreadID = id; x=UwyZ
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 uafSz@`  
} X=:|v<E   
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public void run() M^i^_}~S;  
{ ;1S~'B&1Q  
while(nStartPos < nEndPos && !bStop) 52*9q!  
{ EJdl%j  
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try{ X+'z@xpj  
URL url = new URL(sURL); NTnjVU }  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Km5#$IiP;  
httpConnection.setRequestProperty("User-Agent","NetFox"); 
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String sProperty = "bytes="+nStartPos+"-"; *5SOXrvhu6  
httpConnection.setRequestProperty("RANGE",sProperty); N36<EHq  
Utility.log(sProperty); S,K'y?6  
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InputStream input = httpConnection.getInputStream(); Hs%;uyI@$  
//logResponseHead(httpConnection); o%!8t_1mR  
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byte[] b = new byte[1024]; QAp+LSm  
int nRead; ?s4-2g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [n[!RddY  
{ 9?VyF'r=  
nStartPos += fileAccessI.write(b,0,nRead); 3GH@|id  
//if(nThreadID == 1) wVI 1sR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =hs !t|(*  
} mSn>  
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Utility.log("Thread " + nThreadID + " is over!"); y^7ol;t  
bDownOver = true; {Vc%ga|E  
//nPos = fileAccessI.write (b,0,nRead); dQ4VpR9|;  
} uF xrv  
catch(Exception e){e.printStackTrace ();} :
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} /H_,1Fu|  
} ~16QdwK  
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//打印回应的头信息 6$1d
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public void logResponseHead(HttpURLConnection con) ohK_~  
{ >^cP]gGY  
for(int i=1;;i++) 'baew8Q#  
{ \q2#ef@2  
String header=con.getHeaderFieldKey(i); CNC3">Dk~9  
if(header!=null) {-(}p+;z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +*dG'U6  
Utility.log(header+" : "+con.getHeaderField(header)); MXSN <  
else }gk37_}X\I  
break; 3Un{Q~6h  
} d$>TC(E=t  
} YC
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^DL}J>
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}GIwYh/  
public void splitterStop() UL81x72O  
{ JArSJ:
}  
bStop = true; OnNWci|7  
} #~A(%a  

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} 8p4J7 -  
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/* .ZuRH_pI  
**FileAccess.java r(ej=aR  
*//文件访问(定位，写)
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package NetFox; )ZxDfRjL  
import java.io.*; Xb0$BAP  
72hN%l   
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public class FileAccessI implements Serializable{ p2]@yE7w  
fj2pD Cic  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /}G+PUk7  
RandomAccessFile oSavedFile; kA`Z#yu  
long nPos; /.Yf&2X\  
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public FileAccessI() throws IOException #fq%903=  
{ ?hpT"N,hF9  
this("",0); \#LkzN8  
} cL31g_u  
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public FileAccessI(String sName,long nPos) throws IOException F`/-Q>Q  
{ _lWC)bv
`  
oSavedFile = new RandomAccessFile(sName,"rw"); [E9V#J89  
this.nPos = nPos; v'R{lXE  
oSavedFile.seek(nPos); m5!~PG:_  
} P}So>P~2  
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\rXmWzl{  
public synchronized int write(byte[] b,int nStart,int nLen) gN2$;hb?  
{ @J`o pR  
int n = -1; (IlHg^"  
try{ .YV{wL@cB  
oSavedFile.write(b,nStart,nLen); *&WkorByW  
n = nLen; #BB,6E   
} )gOVnA/M  
catch(IOException e) lSMv9:N  
{ bve_*7
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e.printStackTrace (); 4*k>M+o/C4  
} RMinZ}/  
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return n; p`/"e<TP  
} !n;0%"(FH  
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} L1'PQV  
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/* BZS%p  
**SiteInfoBean.java |l
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*/ K|i:tHF]@  
package NetFox; V=$pXpro%  

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&  
public class SiteInfoBean { w}8 ,ICL  
t

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private String sSiteURL; //Site's URL fQW1&lFT  
private String sFilePath; //Saved File's Path 0P{^aSxTP  
private String sFileName; //Saved File's Name U2v;[>=]  
private int nSplitter; //Count of Splited Downloading File [HRry2#s  
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public SiteInfoBean() :;Lt~:0b~  
{//nSplitter的缺省值为5 2C6o?*RjyY  
//default value of nSplitter is 5 mLEJt,X  
this("","","",5); v'Y0|9c  
} &a;{ed1B  
!,Ou:E?Bb  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nt 9LBea  
{ zd%n)jlwR  
sSiteURL= sURL; :B^YK].  
sFilePath = sPath; f ZEyXb  
sFileName = sName; A-n@:` n~  
this.nSplitter = nSpiltter; Mi>!  
+3>)r{#k  
u+5&^"72,  
} ?;GbK2\bj  
YC!IIE_  
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public String getSSiteURL() _GhP{C$  
{ |IcA8[  
return sSiteURL; 0oNNEC  
} L3/SIoqd  
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public void setSSiteURL(String value) *F<Ar\f
5  
{ (Q]Ww_r~  
sSiteURL = value; |wxAdPe  
} Abw=x4d(i  
V
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public String getSFilePath() 3_DwqZ 'O  
{ -dto46X  
return sFilePath; ;JuBybJb  
} #QUQC2P(~  
#&k`-@b5|  
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public void setSFilePath(String value) ;\'d9C  
{ 7@W}>gnf  
sFilePath = value; Io;x~i09K  
} `4Swd
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public String getSFileName() <r>1W~bp.q  
{ \CU-a`n  
return sFileName; rSgOQ  
} N*1{yl76x  
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public void setSFileName(String value) [ML|,kq!  
{ ;aj4V<@  
sFileName = value; 3>T2k }  
} A"3"f8P8a  
3(oB[9]s  
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public int getNSplitter() 5cF7w  
{ QmKEl|/{u  
return nSplitter; 5!s7`w]8*0  
} Al MMN"j  
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public void setNSplitter(int nCount) g`Kh&|GU  
{ 1 u~Xk?  
nSplitter = nCount; [mcER4]}  
} ;RW0Dn)Q  
} I^GZ9@UE  
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r`\6+Ntb.  
/* Op_(10|  
**Utility.java 3/{,}F$  
*/ j5:/Gl8  
package NetFox;  NZu2D  
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public class Utility { ?mp}_x#=  
:|HCUZ*H(T  
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public Utility() t"$#KP<  
{ ysH'X95  
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o.g)[$M8cF  
} 01<Ti"  
a7>^^?|  
//线程睡眠 Wx`$hvdq  
public static void sleep(int nSecond) Ln$= 8x^T  
{ grxlGS~Q  
try{ sTu]C +A  
Thread.sleep(nSecond); -NPX;e$<  
} ="(' #o  
catch(Exception e) GK`U<.[c  
{ Z [YSET  
e.printStackTrace (); MP|$+yuR~  
} s?Z{LWZ@  
} p_B5fm7#6W  
XY,!v
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//日志 M^&^g  
public static void log(String sMsg) 2{xf{)hO?  
{
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System.err.println(sMsg); !BjJ5m  
} v
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=/+f3  
public static void log(int sMsg) 8dLK5"_3  
{ Ez+8B|0P  
System.err.println(sMsg); NydF'N_1  
} no,b_0@N  
} a_\t(U  
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u\3=m%1  
/* -`CE;  
**TestMethod.java A~@x8  
*/ pG^>y0  
package NetFox; uC|bC#;  
%$&_!  
ew&"n2r  
public class TestMethod { cS%;JV>C  
a] P0PH~  
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public TestMethod() T2}X~A  
{ ///xx/weblogic60b2_win.exe =<X4LO)C  
try{ XC!Y {lp  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f_z]kA +H  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]Jnrs  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E/hO0Ox6  
fileFetch.start(); Y^QG\6q  
} 3~\,VO''  
catch(Exception e){e.printStackTrace ();} H}cq|hodn  
.|i/ a%J  
ig^x%!;  
} ! JauMR  
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public static void main(String[] args) :j`4nXm  
{ X`A+/{ H  
new TestMethod(); 7;a  
} ^g=j`f[T  
} 6eQa@[.Q  
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