http断点续传简单实现（java)

/* 5tbCx!tL  
**SiteFileFetch.java Wn@oG@}~  
*/ %eDSo9Y  
package NetFox; by @qg:  
import java.io.*; @iuX~QA[9  
import java.net.*; :k1?
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public class SiteFileFetch extends Thread { hb3:,c(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 3oLF^^^g  
long[] nStartPos; //开始位置 .>R`#@+I  
long[] nEndPos; //结束位置 8)9-*Bzj
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 YXWDbr:JX  
long nFileLength; //文件长度 U|Fqna  
boolean bFirst = true; //是否第一次取文件 v3Vve:}+  
boolean bStop = false; //停止标志 3xs<w7  
File tmpFile; //文件下载的临时信息 Lf5zHUH  
DataOutputStream output; //输出到文件的输出流 90W=v*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） UVD D)  
public SiteFileFetch(SiteInfoBean bean) throws IOException M@{?#MkS%  
{ Y bJg{Sb  
siteInfoBean = bean; CjpGo}a/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #G]IEO$M6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5eff3qrH{  
if(tmpFile.exists ()) BC.3U.  
{ d9S/_iCI  
bFirst = false; ny13+Q`^  
read_nPos(); .S54:vs  
} ]?VVwft  
else ~#)hqU'  
{ rah"\f2  
nStartPos = new long[bean.getNSplitter()]; .?6p~  
nEndPos = new long[bean.getNSplitter()]; #[=
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} R*:$^v@4  
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} 5]Rbzg2t  
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public void run() >p
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{  6a,8t  
//获得文件长度 n%F _3`  
//分割文件 ,K,st+s|  
//实例FileSplitterFetch s>6h]H  
//启动FileSplitterFetch线程 HN5661;8  
//等待子线程返回 ;"Gy5  
try{ O ixqou  
if(bFirst) {4 Yxh8  
{ Bz }nP9  
nFileLength = getFileSize(); EF :g0$  
if(nFileLength == -1) [M[#f&=Z  
{ jOfG}:>e\  
System.err.println("File Length is not known!"); 6ncwa<q5  
} e& `"}^X;I  
else if(nFileLength == -2) _:9}RT?  
{ es6YxMg  
System.err.println("File is not access!"); e}?Q&Lci  
} bfA>kn0C  
else Qg/FFn^Kg*  
{ l0,VN,$Yl  
for(int i=0;i<nStartPos.length;i++) Am*IC?@tq  
{ B%\&Q@X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _\\Al v.  
} ]\^O(BzB  
for(int i=0;i<nEndPos.length-1;i++) {BJ>x:2  
{ ir}z^+  
nEndPos = nStartPos[i+1];
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} 0
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nEndPos[nEndPos.length-1] = nFileLength; WCsf_1  
} GrG'G(NQ  
} gV.?Myy  
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//启动子线程 i+O7,"(@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) lW|=rq-|  
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -6DRX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `$> Y  
nStartPos,nEndPos,i); 5c::U=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *90dkJZ.  
fileSplitterFetch.start(); _33b %  
} b_TI_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F62 uDyY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); RWR{jM]V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5?$MZaT  
nEndPos = " + nFileLength); _R
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// fileSplitterFetch[nPos.length-1].start(); &7\}Sqp  
wIi(\]Q  
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//等待子线程结束 s\ C,5  
//int count = 0; NC~?4F[  
//是否结束while循环 =i vlS  
boolean breakWhile = false; B<EqzP*#  
 ]+Whv%M  
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while(!bStop) 2*75*EQCH  
{ *>W<n1r@]  
write_nPos(); 7T[$BrO\  
Utility.sleep(500); nPvys~D  
breakWhile = true; mBwz.KEm<  
8D)1ZUx7`  
2Jt{oh|  
for(int i=0;i<nStartPos.length;i++) ;l!<A  
{ 3H!]X M  
if(!fileSplitterFetch.bDownOver) i_N8)Z;r  
{ HFP'b=?`]|  
breakWhile = false; AI3x,rk#  
break; 
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} ZS+m}.,whQ  
} 8i[TeW"  
if(breakWhile) Kuh3.1#o  
break; H(;@7dh  
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W<)nC_$  
//count++; 2z !
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//if(count>4) L~PiDQr?r  
// siteStop(); {g nl6+j  
} QP\:wi  
#$W5)6ch  
1"CWEL`i  
System.err.println("文件下载结束！"); ?rOj?J9  
} `WH$rx!  
catch(Exception e){e.printStackTrace ();} n`Z}tQ%)o  
} ~OX\R"aZBW  
>/\TG8t,f  
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//获得文件长度 nZi&`HjQ  
public long getFileSize() aR3jeB,=x  
{ MuWZf2C  
int nFileLength = -1; czIEkm  
try{ <6-73LsHcP  
URL url = new URL(siteInfoBean.getSSiteURL()); Z]uc *Ed  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {,5.svO  
httpConnection.setRequestProperty("User-Agent","NetFox"); >8{w0hh;  
~"%'(j_4  
Ry}4MEq]  
int responseCode=httpConnection.getResponseCode(); 2fkyz  
if(responseCode>=400) 4RDY_HgF6  
{ *-=/"m  
processErrorCode(responseCode); &Y1h=,KR9  
return -2; //-2 represent access is error f4pIF"U9>  
} ?J2A.x5`a  
\LJ!X3TZ  
@#hQ0F8  
String sHeader; %'WC7s  
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for(int i=1;;i++) pmBN?<  
{ w!<e#Z]3b  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !x-__[#  
//Utility.log(in.readLine()); 3M?O(oO  
sHeader=httpConnection.getHeaderFieldKey(i); %1p-DX6  
if(sHeader!=null) 4I&(>9 @z<  
{ rNhS\1-  
if(sHeader.equals("Content-Length")) rF[-4t %  
{ G HQ~{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); GmNCw5F  
break; e~gNGr]L/  
} 8Y8bFWuc  
} &iu]M=Yb  
else 4 ;_g9]  
break; }=f\WWJf0  
} L44|/~  
} ~6t<`&f  
catch(IOException e){e.printStackTrace ();} 7l-MVn_8  
catch(Exception e){e.printStackTrace ();} =U~53Tg  
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Utility.log(nFileLength); <=_!8A  
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return nFileLength; [L-wAk:Fb  
} Kn$t_7AF^  
?`Z:vqp>Z  
{Pe&J2 +  
//保存下载信息（文件指针位置） 7_3 PM 3C  
private void write_nPos() 8>j&) @q  
{ oMAUR "  
try{ ylos6]zS8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); VTR4uT-  
output.writeInt(nStartPos.length); v(0ujfSR0  
for(int i=0;i<nStartPos.length;i++) au19Q*r9  
{ G[ns^  
// output.writeLong(nPos); c/.s`hz  
output.writeLong(fileSplitterFetch.nStartPos); =#4>c8MM  
output.writeLong(fileSplitterFetch.nEndPos); %x,HQNRDU  
} 1O,5bi>t7  
output.close(); 4E=QO!pVv  
} Chl^LEN:  
catch(IOException e){e.printStackTrace ();} dY.X/f  
catch(Exception e){e.printStackTrace ();} eN5F@isy  
} VWt=9D;  
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\kV|S=~@  
//读取保存的下载信息（文件指针位置） #l
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private void read_nPos() AW\uE[kg  
{ 2sgp$r  
try{ lAG@nh^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wvisu\V  
int nCount = input.readInt(); @$kzes\  
nStartPos = new long[nCount]; 9Bpb?  
nEndPos = new long[nCount]; ?{ \7th37  
for(int i=0;i<nStartPos.length;i++) id+EBVHAd  
{ :I/9j=@1  
nStartPos = input.readLong(); s+_8U}R  
nEndPos = input.readLong();
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} qYVeFSS  
input.close(); euV!U}Xr  
} A`~?2LH,~F  
catch(IOException e){e.printStackTrace ();} (qR;6l  
catch(Exception e){e.printStackTrace ();} \;_tXb}F  
} L;g2ZoqIr0  
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private void processErrorCode(int nErrorCode) 8cvSA&l(D  
{ 0iC5,  
System.err.println("Error Code : " + nErrorCode); 1,zc8>M  
} -#;ZZ\fdj  
%L)QTv/  
BE&8E\w  
//停止文件下载 *1-0s*T  
public void siteStop() HD{u
#~8{  
{ dg*xo9Xi`  
bStop = true; EJz!#f~  
for(int i=0;i<nStartPos.length;i++) . WJ  
fileSplitterFetch.splitterStop(); Q~Nq5[  
+B8oW3v# )  
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} dtV*CX.D.7  
} f6SXXkO+  
//负责部分文件的抓取 zV15d91GX  
**FileSplitterFetch.java /W f.Gt9[  
*/ #D(=[F  
package NetFox; |;aZi?Ek[  
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import java.io.*; ldU ><xc2  
import java.net.*; ZvXw#0)v  
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public class FileSplitterFetch extends Thread { N&G(`]  
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String sURL; //File URL `tT7&*Os  
long nStartPos; //File Snippet Start Position l{?9R.L  
long nEndPos; //File Snippet End Position GU1
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int nThreadID; //Thread's ID 5i{J0/'Xu)  
boolean bDownOver = false; //Downing is over sm[zE/2b  
boolean bStop = false; //Stop identical FncP,F$8   
FileAccessI fileAccessI = null; //File Access interface wj'fdrY5h  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ; %AgKgV  
{ Rq",;,0ZJ  
this.sURL = sURL; MVQ6I/EA4  
this.nStartPos = nStart; =D?HL?  
this.nEndPos = nEnd; qK
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nThreadID = id; D>U(&n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ln+.$ C  
} Y>E` 7n  
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public void run() c9nv=?/}f  
{ )FA:
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while(nStartPos < nEndPos && !bStop) FW3E UC)P  
{ Xfb-< Q0A  
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try{ e<A>??h^  
URL url = new URL(sURL); }43qpJe8U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vz:VegS  
httpConnection.setRequestProperty("User-Agent","NetFox"); (VCJn<@@  
String sProperty = "bytes="+nStartPos+"-"; GqP02P'2  
httpConnection.setRequestProperty("RANGE",sProperty);  fOsvOC  
Utility.log(sProperty); |,TBP@  
/-^{$$eu  
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InputStream input = httpConnection.getInputStream(); F$|d#ny  
//logResponseHead(httpConnection); 8OS^3JS3"  
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U? U3?Y-k`  
byte[] b = new byte[1024]; - ?  i  
int nRead; z~2;u5S&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S;#7B?j  
{ !-SI &qy  
nStartPos += fileAccessI.write(b,0,nRead); ?caHS2%?ae  
//if(nThreadID == 1) _x$Eq: i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0,#n_"  
} Y@Ry oJ  
t
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Utility.log("Thread " + nThreadID + " is over!"); Gp?pSI,b.t  
bDownOver = true; B'y)bY'_dS  
//nPos = fileAccessI.write (b,0,nRead); :UKc:JVNM  
} 6RSit  
catch(Exception e){e.printStackTrace ();} ZRr.kN+F  
} ]haQ#e}WH  
} '['x'G50  
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//打印回应的头信息 i_!$bk<yo  
public void logResponseHead(HttpURLConnection con) ^H&`e"|R9  
{ #?>p
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for(int i=1;;i++) cnY}^_  
{ )T slI  
String header=con.getHeaderFieldKey(i); ;kG"m7-/  
if(header!=null) )C0Iy.N-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); uXA}" f2  
Utility.log(header+" : "+con.getHeaderField(header)); S]e;p\8$Z  
else ( YZ2&  
break; 7#N= GN  
} 64'sJc.   
} 7^#O{QYol  
(\ |Go-2G  
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public void splitterStop()  ME5M;bz(  
{ PyQ\O*  
bStop = true; Kb/qM}jS  
} $(yi+v  
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@!!5el {  
} Smh=Q4,W  
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8|!"CQJ|H  
/* (Dba!zSs  
**FileAccess.java *
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*//文件访问(定位，写) /Ea&Zm  
package NetFox; (2RuQgO  
import java.io.*; B\ZCJaMb  
?;_Mxal'  
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public class FileAccessI implements Serializable{ >@-BZJg/k  
wr>6Go%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'OU3-K  
RandomAccessFile oSavedFile; :$XlYJrjK  
long nPos; -<u_fv  
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public FileAccessI() throws IOException .\ vrBf  
{ K'K/}q<  
this("",0); a]8W32  
} w`/~y   
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public FileAccessI(String sName,long nPos) throws IOException + :b"0pu-H  
{ '+GYw$  
oSavedFile = new RandomAccessFile(sName,"rw"); #~r+Z[(,p  
this.nPos = nPos; IFtaoK  
oSavedFile.seek(nPos); 9T2y2d!X  
} x|Ms2.!  
&TN.6Hm3  
$/E{3aT@F2  
public synchronized int write(byte[] b,int nStart,int nLen) s`]SK^j0  
{ G2=dq  
int n = -1; 4~d:@Gmk&  
try{ po*r14f  
oSavedFile.write(b,nStart,nLen); B+c,3@)x  
n = nLen; =,s5>2  
} 1l.HQ IS  
catch(IOException e) vcP_gJz  
{ 7VLn$q]:  
e.printStackTrace (); +Q:)zE  
} zUWWXC%R  
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_( QW2m?K  
return n; *M$$%G(4  
} E7<l^/<2S+  
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} Xw162/:h  
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4Ub7T=LG  
/* raR=k!3i  
**SiteInfoBean.java 7?uIl9Vk>(  
*/ w:~
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package NetFox; :{-/b  
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public class SiteInfoBean { 3_J({  
8;3I:z&muQ  
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private String sSiteURL; //Site's URL &sJ6k/l  
private String sFilePath; //Saved File's Path >
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private String sFileName; //Saved File's Name QC1\Sn/  
private int nSplitter; //Count of Splited Downloading File 2FN#63  
 {C%f~j  
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public SiteInfoBean() ,Mn`kL<F  
{//nSplitter的缺省值为5 Ai`0Ud,M@  
//default value of nSplitter is 5 hdbm8C3  
this("","","",5); Ed#Hilk'  
} tSTl#xy  
8`|Z9umW*  
/!hxW}>^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;F/w&u.n  
{ V~QOl=`K:  
sSiteURL= sURL; o"qG'\x  
sFilePath = sPath; aBKJd  
sFileName = sName; [-nPHmZV[  
this.nSplitter = nSpiltter; G;J!3A;TE  
h-%RSei5  
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} 4B-+DH>{6  
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public String getSSiteURL() a.XMeB  
{ jq(rnbV  
return sSiteURL;
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} 8@KGc )k  
\Bl`;uXb  
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public void setSSiteURL(String value) p'=XW#2 >  
{ R1Q~UX]d=  
sSiteURL = value; or[!C%  
} 2'}/aL|G  
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2&2t8.<  
public String getSFilePath() L#MM
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{ 0w6"p>s>c  
return sFilePath; 2-rfFqpe  
} F441K,I  
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public void setSFilePath(String value) t'HrI-x  
{ ,'@t.XP  
sFilePath = value; Nkk+*(Z  
} %p^`,b}  
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mHc5NkvQC  
public String getSFileName() gV-A+;u  
{ Yi|Nd;  
return sFileName; Ne}x(uRn  
} [:l=>yJ{(  
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public void setSFileName(String value) F2',3  
{ %5<X
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sFileName = value; y+M9{[ i/O  
} @zig{b8  
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35~1$uRA  
public int getNSplitter() 28lor&Cc  
{ #!w7E,UBi  
return nSplitter; v3r<k
NW_  
} X>Y>1fI.  
ov|pXi<e  
*YP;HL  
public void setNSplitter(int nCount) H) q_9<;  
{ uL=FK  
nSplitter = nCount; k}e~xbh-y  
} +<sv/gEt  
} Vd A!tL  
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{br6*  
/* y2>AbrJ  
**Utility.java \!4_m8?  
*/ /Hyi/D{W  
package NetFox; +\25ynM

 
{0\9HI@  
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public class Utility { evz@c)8  
+{s -Fg  
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public Utility() i0&W}Bb'  
{ "Pzh#rYY~W  
4X$|jGQ\  
= Tq\Ag:  
} GNoUn7Y  
uX+ YH  
//线程睡眠 8]l(D  
public static void sleep(int nSecond) vFi+ExBU  
{ fD2)/5j1  
try{ T!t9`I0Zz  
Thread.sleep(nSecond); dEPLkv  
} x+W,P  
catch(Exception e) &LHS<Nv^:  
{ /vw$3,*z  
e.printStackTrace (); B[;aNyd<  
} 6rN.)dL.#N  
} [(Ihue  
jL:GP
}I=
 
//日志 9QEK|x`8  
public static void log(String sMsg) ;~(yv|f6  
{ i?'|}tK  
System.err.println(sMsg); $SdpF-'  
} ,y[8Vz?:  
=v=u+nO  
6sNw#pqh  
public static void log(int sMsg) GyQvodqD  
{ Qv1cf  
System.err.println(sMsg); +*x9$LSD  
} m[Cp G=32B  
} \ 9#X]H  
*fQn!2}=(  
+RyV"&v  
/* a[NR%Xq
  
**TestMethod.java z#/"5 l   
*/ 3?<LWrhV3  
package NetFox; V6fJaZ  
O@`KGZEPY  
~SYW@o  
public class TestMethod { .FA99|:  
b-YmS=*  
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public TestMethod() $dF$-y<[0  
{ ///xx/weblogic60b2_win.exe Z~ u3{  
try{ fY!9i5@'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); nt*K@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !twYjOryH[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N;i\.oY  
fileFetch.start(); /NQ PTr  
} t
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catch(Exception e){e.printStackTrace ();} Sgn<=8,6c  
'j\mz5#s  
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} C(2kx4n  
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public static void main(String[] args) NF'<8{~  
{ _Oy;:XN  
new TestMethod(); }gKJ~9Jg  
} 2Wr^#PY60  
} $aHHXd}@t2  
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