http断点续传简单实现（java)

/* av)?>J~;  
**SiteFileFetch.java OqtQA#uL  
*/ Ln:lC( '  
package NetFox; O!/ekU|,r  
import java.io.*; ,b$z!dvhl  
import java.net.*; Ac J>$L)  
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public class SiteFileFetch extends Thread { l4zw]AYk+X  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~bWhth2*  
long[] nStartPos; //开始位置 JXL'\De ;  
long[] nEndPos; //结束位置 m!;G/s*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;
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long nFileLength; //文件长度 ,|A{!j`  
boolean bFirst = true; //是否第一次取文件 t]4!{~,  
boolean bStop = false; //停止标志 J, r Xx:  
File tmpFile; //文件下载的临时信息 (VEp~BW@-R  
DataOutputStream output; //输出到文件的输出流 ;e2
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _;#9!"&  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2av*o~|J*:  
{ Zct!/u9 Q  
siteInfoBean = bean; z1#o
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,^HS`!s[ E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (N7O+3+G  
if(tmpFile.exists ()) ve6x/ PD  
{ SijS5irfk  
bFirst = false; $ND90my  
read_nPos(); Q]^Yi1PbS  
} <;aJ#qT  
else !KAsvF,j  
{ #sS9vv7i  
nStartPos = new long[bean.getNSplitter()]; h>| g2h  
nEndPos = new long[bean.getNSplitter()]; QsM*wT&aa  
} ;c$@@l  
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} j6HR&vIM  
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public void run() j!7Qw 8  
{ ZRPE-l_3:  
//获得文件长度 my4\mi6P  
//分割文件 $3]b>v  
//实例FileSplitterFetch tGC2 ^a#~  
//启动FileSplitterFetch线程 Tn /Ut}]O  
//等待子线程返回 {!MVc<G.  
try{ an.`dBm  
if(bFirst) -( (Z@T1k  
{ O<>#>[  
nFileLength = getFileSize(); @"w2R$o  
if(nFileLength == -1) v[smQO  
{ VE*j*U j  
System.err.println("File Length is not known!"); _!%M%  
} *Er? C;  
else if(nFileLength == -2) ]H>+m 9  
{ h mds(lv7  
System.err.println("File is not access!"); SYeE) mI  
} `2,a(Sk#  
else LZ4xfB(  
{ f0u56I9  
for(int i=0;i<nStartPos.length;i++) -w\M-wc/$  
{ ljuNs@q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1TIlIN
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} Ww=O=c5uOu  
for(int i=0;i<nEndPos.length-1;i++) %EWq2'/5  
{ :pb67Al29  
nEndPos = nStartPos[i+1]; ;$z7[+M  
} 3T?f5+@I  
nEndPos[nEndPos.length-1] = nFileLength; 'u1=XX h  
} ~GA8_B  
} &kiF/F 1  
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//启动子线程 e62y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _;7fraqX  
for(int i=0;i<nStartPos.length;i++) |_, /u_  
{ 0 7\02f  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ><K!~pst}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]Z/R!y?l"G  
nStartPos,nEndPos,i); "
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @+:4J_N  
fileSplitterFetch.start(); gvGi%gq  
} %Ci^*zb  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d@Q][7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r^Y~mq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ok*Z  
nEndPos = " + nFileLength); >T QZk4$  
// fileSplitterFetch[nPos.length-1].start(); {\L|s5=yr  
@C=M UT-!  
9qre|AA  
//等待子线程结束 v&r=-}z2!  
//int count = 0; u1N1n;#  
//是否结束while循环 ^aHh{
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boolean breakWhile = false; M%|f+u&  
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while(!bStop) L1{T ?aII  
{ aHC%19UN  
write_nPos(); 9T?64t<Ju  
Utility.sleep(500); 5uttv:@=  
breakWhile = true; r6MB"4xd  
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for(int i=0;i<nStartPos.length;i++) '#<> "|  
{ Y&g&n o_  
if(!fileSplitterFetch.bDownOver) drIK(u\_  
{ l2s{~IC  
breakWhile = false; pC
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break; 'W(xgOP1  
} (AuPZ  
} "S(yZ6r"  
if(breakWhile) e3g_At\  
break; rREzM)GA  
/
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//count++; oq. r\r  
//if(count>4) Ye@t_,)x  
// siteStop(); wV:C<Mg7q  
} }[
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System.err.println("文件下载结束！"); YZ**;"<G  
} ;cLUnsB\  
catch(Exception e){e.printStackTrace ();} 3~<}bee5|q  
} sf)W~Lx5a  
:".w{0l@  
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//获得文件长度 c D7FfJ  
public long getFileSize() fv2=B)8$  
{ 4.'JLArw  
int nFileLength = -1; GS4_j
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try{ mW +tV1XjG  
URL url = new URL(siteInfoBean.getSSiteURL()); .8(%4ejJ(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;UpJ=?W  
httpConnection.setRequestProperty("User-Agent","NetFox"); :Eo8v$W\RB  
/>F.Nsujy  
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int responseCode=httpConnection.getResponseCode(); T>F9Hs W  
if(responseCode>=400) /WYh[XKe  
{ dhtb?n{  
processErrorCode(responseCode); OpQ8\[X+  
return -2; //-2 represent access is error KuXkI;63J>  
} H`el#tt_  
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String sHeader; L {qJ-ln:  
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for(int i=1;;i++) )8'jxiGs  
{ PUCx]5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ag6uR(uI  
//Utility.log(in.readLine());
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sHeader=httpConnection.getHeaderFieldKey(i); |7c`(.  
if(sHeader!=null) @c]Xh:I  
{ */_@a?  
if(sHeader.equals("Content-Length")) Q7(eq0na  
{ CjKRP;5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?bI?GvSh  
break; m8AAp1=  
} ve-8*Xa  
} 3I*uV!notJ  
else h'!V8'}O?  
break; t7^D-l  
} DY.58IHg1  
} l{Er+)a  
catch(IOException e){e.printStackTrace ();} u E.^w;~2=  
catch(Exception e){e.printStackTrace ();} _Wma\(3$  
 +>#e=nH  
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Utility.log(nFileLength); $eX*  
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return nFileLength; O^NP0E  
} WK4@:k m6)  
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//保存下载信息（文件指针位置） ZAeQ~
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private void write_nPos() (}"S)#C  
{ n1 v,#GE  
try{ ! Rvn'|!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X" \}sl5
 
output.writeInt(nStartPos.length); sOQcx\dK  
for(int i=0;i<nStartPos.length;i++) M=[th  
{ QiU_hz6?v  
// output.writeLong(nPos); r0Z+RB^I  
output.writeLong(fileSplitterFetch.nStartPos); =YHt9fb$c  
output.writeLong(fileSplitterFetch.nEndPos); j ug'g  
} j+Zt.KXjT  
output.close(); #_fY4vEO  
} ?gG,
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catch(IOException e){e.printStackTrace ();} MD4\QNUa)*  
catch(Exception e){e.printStackTrace ();} ^@"c`  
} k>>`fE\K  
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//读取保存的下载信息（文件指针位置） ev"M;"y  
private void read_nPos() r=$gT@  
{ WIG=D{\Yx  
try{ Tq#<Po $  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =G>.-Qfs  
int nCount = input.readInt(); q^]tyU!w  
nStartPos = new long[nCount]; Q!]IG;3Sx|  
nEndPos = new long[nCount]; (YrR8  
for(int i=0;i<nStartPos.length;i++) w[sR7T9*  
{ [Xh\mDU.  
nStartPos = input.readLong(); pYh!]0n  
nEndPos = input.readLong(); $T/#1w P  
} = t-fYV  
input.close(); PCZ]R  
} +6376$dC  
catch(IOException e){e.printStackTrace ();} pL)xqKj  
catch(Exception e){e.printStackTrace ();} @H+~2;B,  
} 9[sG1eP!  
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private void processErrorCode(int nErrorCode) 9GPb$gtx  
{ j{"[Ec  
System.err.println("Error Code : " + nErrorCode); "Z~`e]>  
} Pw xIz  
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//停止文件下载 {XHk6w *-  
public void siteStop() |*E"G5WZM  
{ ~d>uXrb  
bStop = true; ~bGnq, .$  
for(int i=0;i<nStartPos.length;i++) h?A'H RyL~  
fileSplitterFetch.splitterStop(); T3rn+BxF7  
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} Y%h}U<y  
} |Ng"C`$oqv  
//负责部分文件的抓取 5m`[MBt2g  
**FileSplitterFetch.java T<M?PlED  
*/ AsAFUuI  
package NetFox; n.Vtc-yZU  
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import java.io.*; >b43%^yii  
import java.net.*; n$ dw<y  
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public class FileSplitterFetch extends Thread { 5H*>  
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String sURL; //File URL x;mJvfX  
long nStartPos; //File Snippet Start Position ]?&H^"=  
long nEndPos; //File Snippet End Position _NT[ ~M_Q  
int nThreadID; //Thread's ID "Y(^F bs  
boolean bDownOver = false; //Downing is over ALAL( f`  
boolean bStop = false; //Stop identical zLK\I~rU!  
FileAccessI fileAccessI = null; //File Access interface @p6@a6N%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6qDfcs  
{ [-]A^?yBM  
this.sURL = sURL; _25d%Ne0  
this.nStartPos = nStart; e{JVXc[D  
this.nEndPos = nEnd; 6WO7+M;z  
nThreadID = id; ~$*`cO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6e/7'TYwT  
} RF!'K ko  
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public void run() 4(8<w cL  
{ FW5}oD(H  
while(nStartPos < nEndPos && !bStop) /W0E(8:C)  
{ =%L@WVbM  
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try{
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URL url = new URL(sURL); EIPnm%{1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c"qPTjY  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6+)x7g1PL  
String sProperty = "bytes="+nStartPos+"-"; shNE~TA  
httpConnection.setRequestProperty("RANGE",sProperty); %Gu][_.L  
Utility.log(sProperty); wn1, EhHt  
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InputStream input = httpConnection.getInputStream(); s,kU*kHn  
//logResponseHead(httpConnection); ,S0UY):(A  
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byte[] b = new byte[1024]; ;.AV;C"  
int nRead; /:KQAM0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
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{ zu C5@jy.x  
nStartPos += fileAccessI.write(b,0,nRead); 2md.S$V$,  
//if(nThreadID == 1) P
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?^F5(B[+Y  
} NFV_+{X\  
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Utility.log("Thread " + nThreadID + " is over!"); I5Q~T5Ar  
bDownOver = true; !%V*UR9  
//nPos = fileAccessI.write (b,0,nRead); 1xIFvXru  
} T$IUKR  
catch(Exception e){e.printStackTrace ();} ~ttKI4  
} wcl!S
{  
} 8UYJye8  
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//打印回应的头信息 M_; w%FV  
public void logResponseHead(HttpURLConnection con)  VmYBa(  
{ Qi"'bWX@  
for(int i=1;;i++) 58PKx5`D  
{ _)q4I(s*  
String header=con.getHeaderFieldKey(i); HGb.656r  
if(header!=null) V>r j$Nc]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5)8.  
Utility.log(header+" : "+con.getHeaderField(header)); 0NrTJ R`  
else .5NZf4:C  
break; rXuAixu!t  
} .c03}RTC^  
} GeVc\$K-  
@~hz_Nm@8  
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public void splitterStop() ;!:F#gahv  
{ )6g&v'dq  
bStop = true; "d2LyQy  
} l)H9J]  
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} [m %W:Ez  
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/* [{?;c+[  
**FileAccess.java *n,UOHlO  
*//文件访问(定位，写) p#z;cjfSt  
package NetFox; r.9 $y/5  
import java.io.*; \1~I04'=  
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public class FileAccessI implements Serializable{ -h=c=P  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s 8Jj6V  
RandomAccessFile oSavedFile; y6bjJ}  
long nPos; Ty.drM  
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public FileAccessI() throws IOException }0vtc[!  
{ wqf&i^_  
this("",0); tG_-;03<`4  
} WVinP(#nfM  
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public FileAccessI(String sName,long nPos) throws IOException UUD\bWfn  
{ JTjzT2`A.  
oSavedFile = new RandomAccessFile(sName,"rw"); ]gEu.Nth`  
this.nPos = nPos; ipfm'aQ  
oSavedFile.seek(nPos); T4l-sJ'|  
} k-io$  
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public synchronized int write(byte[] b,int nStart,int nLen) 8Er[M  
{ 7G?Ia%u  
int n = -1; F>TYVxQ  
try{ $+iu\MuX  
oSavedFile.write(b,nStart,nLen); zz[g{[SN  
n = nLen; ?!R
%o  
} {7/A  
catch(IOException e) 1`nc8qC  
{ xcsFODx~  
e.printStackTrace (); >c&4_?d&,A  
} {jrZ?e-q  
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return n; #*[,woNk  
} 2lX[hFa5  
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} sb8z_3  
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/* @"jmI&hYn  
**SiteInfoBean.java nl.~^CP  
*/ S$Ns8=  
package NetFox; 9@kcK  
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public class SiteInfoBean { u XaL  
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private String sSiteURL; //Site's URL ,<`|-oa  
private String sFilePath; //Saved File's Path c1gz#,  
private String sFileName; //Saved File's Name YK(XS"Kl  
private int nSplitter; //Count of Splited Downloading File 0F-mROC=F  
]JkpRaP$  
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public SiteInfoBean() !pG+Ak?  
{//nSplitter的缺省值为5 2O}s*C$Xav  
//default value of nSplitter is 5 de*,MkZN  
this("","","",5); (YaOh^T:|  
} L3-<Kop  
i=
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6RR4L^(m  
{ 4`?sE*P@`  
sSiteURL= sURL; ~)WfJ  
sFilePath = sPath; #L|JkBia  
sFileName = sName; -='8_B/75  
this.nSplitter = nSpiltter; g}\U, (  
?6_"nT*}  
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} Ak<IHp^Q  
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48R]\B<R{  
public String getSSiteURL() b'1/cY/!  
{ yffU% )  
return sSiteURL; ?Cc
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} vHZX9LQU0+  
R
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public void setSSiteURL(String value) ph}wnIW]  
{ SSSDl$}'t  
sSiteURL = value; P_:?}h\  
} awj}K  
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public String getSFilePath() *K0j5dx  
{ *DPTkMQN  
return sFilePath; zLJ:U`uh\  
} I@y2HxM  
~;!i)[-  
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public void setSFilePath(String value) $9j>VGf=
 
{ n1k$)S$iiy  
sFilePath = value; Wl9I`Itg  
} a#OhWqu$  
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#`YxoY`  
public String getSFileName() z=- 8iks|  
{ [[.&,6  
return sFileName; -KJ}.q>upq  
} ` $QzTv   
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public void setSFileName(String value) ;%b <uV  
{ -.+KCt G$+  
sFileName = value; jL>I5f  
} N9>'/jgZX  
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public int getNSplitter() '.}6]l  
{ yNb

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return nSplitter; utFcFdX  
} .:r2BgL  
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public void setNSplitter(int nCount) ],fwZd[t  
{ ~#N.!e4  
nSplitter = nCount; >%jEo'0;_  
} t
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} $2 +$,:  
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/ut~jf`  
/* UG^?a  
**Utility.java *x#&[>  
*/ N('S2yfDR  
package NetFox; )N%1%bg^-  
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public class Utility { Ztpm_P6  
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{C,1w  
public Utility() yv#c=v|  
{ J _[e9  
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} >X\s[d&(  
.9[8H:Fe  
//线程睡眠 #%=vy\r  
public static void sleep(int nSecond) e{rHO,#A>  
{ 3ZJagJ\O  
try{ y9re17{ X  
Thread.sleep(nSecond); kVG6\<c]  
} 9 FFfRIVY  
catch(Exception e) F~d7;x=g  
{ 2A18hP`^  
e.printStackTrace (); LK-K_!F  
} /Mi-lh^j-  
} 9B?t3:  
w7*b}D@65\  
//日志 BF1O|Q|d6  
public static void log(String sMsg) ,$zSJzS  
{ #G4~]Qml  
System.err.println(sMsg); @e?[oojrM  
} wEHrer  
:.'T+LI  
MTFVnoZMQ_  
public static void log(int sMsg) r* /XB0  
{ A86lyBDQ*  
System.err.println(sMsg); ZjI/zqBm  
} f)s_e  
} <DlanczziF  
&L~31Ayj&  
Zy+QA>d|  
/* g]PLW3  
**TestMethod.java fE7a]REK  
*/ WNlSve)]ie  
package NetFox; lh(+X-}D  
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public class TestMethod { {'K;aJ'\  
 =R24h  
w2C!>fJ]1  
public TestMethod() Mpl,}Q!c  
{ ///xx/weblogic60b2_win.exe @vYN7  
try{ ZX5A%`<M  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9{^B Tc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t[yD8h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;x0KaFk  
fileFetch.start(); Sy0s`\[  
} [sO<6?LY  
catch(Exception e){e.printStackTrace ();} VL!kX``^F  
rgvc5p  
t;f p<z7N.  
} ?[4khQt  
Y
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public static void main(String[] args) F]&J%i F[  
{ &#b>AAx$2Y  
new TestMethod(); <~8f0+"  
}
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} {arjW3~M:  
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