http断点续传简单实现（java)

/* sRSz}]  
**SiteFileFetch.java ]z/Zq  
*/ fKH7xu!V4+  
package NetFox; \Ig68dFf%  
import java.io.*; K5Q43e1  
import java.net.*; {\H/y c|@  
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public class SiteFileFetch extends Thread { aNcd` $0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Vd^g9  
long[] nStartPos; //开始位置 E 99hlY~1:  
long[] nEndPos; //结束位置 $YxBE`)d-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 M_v?9L  
long nFileLength; //文件长度 j9Ybx#  
boolean bFirst = true; //是否第一次取文件 ^G&3sF}  
boolean bStop = false; //停止标志 ">f erhN9  
File tmpFile; //文件下载的临时信息 &LO"g0w  
DataOutputStream output; //输出到文件的输出流 aj8A8ma*}  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :x.7vZzxs  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~h}Fi  
{
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siteInfoBean = bean; SIO&rrT.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [B@'kwD\l  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); '* mH*?Y  
if(tmpFile.exists ()) &Z(K6U#.  
{ |-sPLU&s%  
bFirst = false; F+R?a+e  
read_nPos(); kiUGZ^k\s  
} :B3[:Mp
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else j',W 64  
{ k@zy  
nStartPos = new long[bean.getNSplitter()]; v+p{|X-  
nEndPos = new long[bean.getNSplitter()]; d->|EJP  
} {3;AwhN0H  
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} XL#[%X9  
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public void run() %CWPbk^  
{ D\IjyZ-O  
//获得文件长度 SJD@&m%?[  
//分割文件 ^,m< 9  
//实例FileSplitterFetch P96pm6H_;  
//启动FileSplitterFetch线程
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//等待子线程返回 zvABU+{jD  
try{ BA\/
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if(bFirst) `:N# 'i  
{ l/;X?g5+  
nFileLength = getFileSize(); B8E'ddUw  
if(nFileLength == -1) ?X@fKAj  
{ n]8<DX99Q0  
System.err.println("File Length is not known!"); N0hE4t  
} ::_i@r  
else if(nFileLength == -2) YK|bXSA[  
{ $kR N h6  
System.err.println("File is not access!"); 8DP+W$  
} x.Q&$#  
else @lJzr3}WZ  
{ <ZU=6Hq  
for(int i=0;i<nStartPos.length;i++) Gt9&)/#  
{ /cc\fw1+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); o7IxJCL=Q  
}  hi
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for(int i=0;i<nEndPos.length-1;i++) [+O"
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{ .<kqJ|SVi  
nEndPos = nStartPos[i+1]; C9p"?vX  
} THmb
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nEndPos[nEndPos.length-1] = nFileLength; y% :4b@<  
} 2]%h$f+  
} E=){K  
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//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; wAnb Di{W  
for(int i=0;i<nStartPos.length;i++) v\(2&*  
{ 2^?:&1:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), apE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n3J53| %v  
nStartPos,nEndPos,i); C6rg<tCH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NcY608C  
fileSplitterFetch.start(); }9nDo*A"}  
} 9"g6C<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c-.t>r&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $-[CG7VgX%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1S@vGq}  
nEndPos = " + nFileLength); JxyB(
 
// fileSplitterFetch[nPos.length-1].start(); q^6+!&"  
B]tIi^  
1sYEZO;  
//等待子线程结束 m3o,@=b  
//int count = 0; 42]pYm(jk3  
//是否结束while循环 DY[$"8Kxcp  
boolean breakWhile = false; YM5fyv?  
~|<m,)!  
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while(!bStop) 'M3">$N  
{ 610D%F  
write_nPos(); WxF:~{  
Utility.sleep(500); [s<^&WM/  
breakWhile = true; L~s3b  
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for(int i=0;i<nStartPos.length;i++) :O5og[;b  
{ ZyE
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if(!fileSplitterFetch.bDownOver) 5xii(\lC  
{ D%JlbH8  
breakWhile = false; ?McQr1  
break; MxBTX4ES  
} N
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} 28 3H  
if(breakWhile) ~F1:N>>_Cf  
break; !ti6  
(%`QhH  
02Ia2e.f  
//count++; L\;6y*K  
//if(count>4) &N3Y|2  
// siteStop(); P6MRd/y |  
} gzeQ|m2]  
hR.@b*q?R  
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System.err.println("文件下载结束！"); JgHM?AWg|  
} .Lfo)?zG  
catch(Exception e){e.printStackTrace ();} Mg^e3D1_  
} Y"KE7>Jf  
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//获得文件长度 n`4K4y%Dy}  
public long getFileSize() w |l1'   
{ cW+t#>'r  
int nFileLength = -1; ,K^4fL$C;3  
try{ _D|^.)=U|  
URL url = new URL(siteInfoBean.getSSiteURL()); f nI|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bO<CR  
httpConnection.setRequestProperty("User-Agent","NetFox"); F4e:ZExJ  
 TT-h;'nJ  
3QpYmX<E  
int responseCode=httpConnection.getResponseCode(); e)?Fi  
if(responseCode>=400) DLCkM*'  
{ b"TjGE  
processErrorCode(responseCode); B
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return -2; //-2 represent access is error Uo-`>7  
}
\%p34K\  
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String sHeader; u a\,->  
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for(int i=1;;i++) D\e8,,H  
{ x|{IwA9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G}9=)  
//Utility.log(in.readLine()); n#iwb0-  
sHeader=httpConnection.getHeaderFieldKey(i); san,|yrMn  
if(sHeader!=null) r#6_]ep}<'  
{ w;l<[q?_  
if(sHeader.equals("Content-Length")) Q3"}Hl2  
{ CA +uKM^"6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %8~3M7
5$  
break; Q~Z=(rP20  
} Vrvic
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} }cN@[3v  
else pD&&l!i&[  
break; D_8x6`z  
} /6_|]ijc  
} SvR7eC  
catch(IOException e){e.printStackTrace ();} 5 QO34t2  
catch(Exception e){e.printStackTrace ();} 'KPASfC  
%sRUh0AL  
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Utility.log(nFileLength); 1 1cWy+8D  
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+[xnZ$Iev  
return nFileLength;
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} ?h1H.s2X
 
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J"FC%\|  
//保存下载信息（文件指针位置） q
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private void write_nPos() )TmHhNo  
{ Ldn8  
try{ CXCpqcC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5MS
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output.writeInt(nStartPos.length); ce6__f5?  
for(int i=0;i<nStartPos.length;i++) CR|lt  
{ EJ`T$JD  
// output.writeLong(nPos); \Y}3cE  
output.writeLong(fileSplitterFetch.nStartPos); mZUfn%QXb(  
output.writeLong(fileSplitterFetch.nEndPos); 3 LdQ]S  
} -Qn=|2Mm?  
output.close(); )P|[r  
} n k2om$nN  
catch(IOException e){e.printStackTrace ();} q5L51KP2  
catch(Exception e){e.printStackTrace ();} 5?Wto4j  
} gI8Bx]  
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//读取保存的下载信息（文件指针位置） w
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private void read_nPos() UswZG^Wh  
{ Zec <m8~  
try{ t R6 +G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); JBnKK  
int nCount = input.readInt(); ~g7l8H67  
nStartPos = new long[nCount]; "4%"&2L  
nEndPos = new long[nCount]; *]i!fzI']  
for(int i=0;i<nStartPos.length;i++) 1$
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{ b2@VxdFN  
nStartPos = input.readLong(); NuU9~gSQ  
nEndPos = input.readLong(); DvM5 k  
} 98.>e  
input.close(); 21(p|`X  
} sFBneBub  
catch(IOException e){e.printStackTrace ();} 1[]&(Pa  
catch(Exception e){e.printStackTrace ();} vp(;W,ba:|  
} #b7$TV  
*kIc9}  
=
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private void processErrorCode(int nErrorCode) $
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{ U8(Nk\"X\  
System.err.println("Error Code : " + nErrorCode); +<prgP`v  
} ;us%/kOR  
",)Qc!^P$  
jV8q)=}*)  
//停止文件下载 hkOsm6  
public void siteStop() "l >Igm  
{ 4Bl{WyMJ|  
bStop = true; ` }3qhar  
for(int i=0;i<nStartPos.length;i++) yAN=2fZm  
fileSplitterFetch.splitterStop(); ?3O9eZY@  
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} D/=5tOy  
} {vo +gRYYv  
//负责部分文件的抓取 +x1eJug4  
**FileSplitterFetch.java Tz9`uW~Mf  
*/ A_;8IlW  
package NetFox; j:w{;(1=W  
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import java.io.*; S"wg2X<  
import java.net.*; fo4.JyBk  
4 QZ?}iz  
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public class FileSplitterFetch extends Thread { x2QIPUlf  
& /4k7X}y  
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String sURL; //File URL "6a8s;  
long nStartPos; //File Snippet Start Position W(hM
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long nEndPos; //File Snippet End Position z]3 `*/B  
int nThreadID; //Thread's ID F,5r9^,_  
boolean bDownOver = false; //Downing is over [TCP-bU  
boolean bStop = false; //Stop identical $'pNp B#vH  
FileAccessI fileAccessI = null; //File Access interface Od?qz1  
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;
}<  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +`uY]Q,O  
{ ^;c16  
this.sURL = sURL; Uje|`<X  
this.nStartPos = nStart; ?GTU=gpQ  
this.nEndPos = nEnd; +I>p !v  
nThreadID = id; 'q * Bdx  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P00f6  
} $v8l0JA *  
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public void run() i55x`>]&sb  
{ [&*6_q"V  
while(nStartPos < nEndPos && !bStop) Ix|~f1*%  
{ '$ef+@y  
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0 'Vg6E]/  
try{ s`Cy a`  
URL url = new URL(sURL); ESoAzo,u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {iG@U=>  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3
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String sProperty = "bytes="+nStartPos+"-";
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httpConnection.setRequestProperty("RANGE",sProperty); Db"DG(  
Utility.log(sProperty); <ER'Ed  
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InputStream input = httpConnection.getInputStream(); B-d(@7,1  
//logResponseHead(httpConnection); *6BThvg|&X  
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byte[] b = new byte[1024]; $0^P0RAH  
int nRead; {7MjP+\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !,Zp? g)  
{ ^h&I H|  
nStartPos += fileAccessI.write(b,0,nRead); C>Is1i^9  
//if(nThreadID == 1) %c)[ kAU!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); saD-D2oj  
} pb0E@C/R  
-|Kzo_" v5  
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Utility.log("Thread " + nThreadID + " is over!"); h O emt  
bDownOver = true; ?GBkqQ  
//nPos = fileAccessI.write (b,0,nRead); !jqWwi  
} U1_&gy @y  
catch(Exception e){e.printStackTrace ();} 6x=Y
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} \C5%\4  
} dd|W@Xp -  
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//打印回应的头信息 8e0."o.6  
public void logResponseHead(HttpURLConnection con) s/Xb^XjS1  
{ htP|3B  
for(int i=1;;i++) 1nPZ<^A&@  
{ w{ `|N$  
String header=con.getHeaderFieldKey(i); #0;HOeIiH  
if(header!=null) j8 C8X$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _#o' +_Z  
Utility.log(header+" : "+con.getHeaderField(header)); }1-I[q6  
else z<]bv7V  
break; s=Q(C[%I  
} U/;]zdP.K  
} r.0oxH']  
A"Q@W<.  
*^ \FIUd  
public void splitterStop() 2i|B=D(  
{ %]p6Kn/>  
bStop = true; =8=!Yc(>  
} hY<{t.ws  
2=ztKfsBhE  
 8RwX=  
} t5 a7DD  
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a <X0e>  
/* u&QKwD Uh  
**FileAccess.java Fl>]&x*~  
*//文件访问(定位，写) 7m5Co>NkuK  
package NetFox; .I$}KE)  
import java.io.*; si(;y](  
uHNpfKnZ  
ix Z)tNz  
public class FileAccessI implements Serializable{ GbU@BN+_  
^+?|Qfi  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )y7_qxwbV  
RandomAccessFile oSavedFile; `"k9wC1  
long nPos; 6@4n'w{"  
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public FileAccessI() throws IOException V:bV ?lt  
{ u@%|kc`  
this("",0); lu UYo  
} N<z`yV  
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public FileAccessI(String sName,long nPos) throws IOException ``?6=mO  
{ A~lIa$U$b  
oSavedFile = new RandomAccessFile(sName,"rw"); >{Rb 3Z]  
this.nPos = nPos; &d`^E6#  
oSavedFile.seek(nPos); m(sXk}e;1  
} N~,_`=yRx  
>Cd9fJ&0gP  
$M"0BZQ?y!  
public synchronized int write(byte[] b,int nStart,int nLen) O2-M1sd$  
{ MmU%%2QG  
int n = -1; Uedvc5><t  
try{ nq`q[KV:  
oSavedFile.write(b,nStart,nLen); bdc\  
n = nLen; iRmQ5ezk  
} CBD_
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catch(IOException e) kRIB<@{  
{ F@YV]u>N  
e.printStackTrace (); |;;!8VO3J  
} f1+qXMs  
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return n; h5@j`{  
} Ri?\m!o  
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} &A50'8B2A  
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/* [5pCL0<c@  
**SiteInfoBean.java W7G9Kx1Y  
*/ nx4P^PC  
package NetFox; P0\eBS  
{^RG% &S  
w4MwD?i]R  
public class SiteInfoBean { fB#XhO  
!jh%}JJ  
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private String sSiteURL; //Site's URL _GbE^  
private String sFilePath; //Saved File's Path Z^tGu7x  
private String sFileName; //Saved File's Name ged,>  
private int nSplitter; //Count of Splited Downloading File S6 }
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public SiteInfoBean() &`:rp!Lc  
{//nSplitter的缺省值为5 ~y\:iL//E  
//default value of nSplitter is 5 +*EKR  
this("","","",5); h$h]%y  
} sj9D  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;A^K_w'  
{ |"}4*V_*  
sSiteURL= sURL; DNth4z  
sFilePath = sPath; F ! )-|n}  
sFileName = sName; |6B6?'  
this.nSplitter = nSpiltter; }bfn_ G  
*)PG-$6X&  
$N.`)S<  
} tjb/[RQ  
aV|k}H{wt  
F RH&B5w  
public String getSSiteURL() lYQtv=q  
{ R#6H'TVE  
return sSiteURL; Y-&|VE2  
} 2lz {_9  
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public void setSSiteURL(String value) @P70W<<  
{ Kx]> fHK  
sSiteURL = value; #Go(tS~o  
} W]LQ &f  
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:,C%01bH|l  
public String getSFilePath() utd:&q|}  
{ R@ QQNYU.D  
return sFilePath; :_c*m@=z(  
} 0!IPcZjY7  
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]GS~i+=M  
public void setSFilePath(String value) RSH/l;ii  
{ "#XtDpGk  
sFilePath = value; y"R("j $  
} ?cBO6^  
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public String getSFileName() /W9 &Ke  
{ 4I.1D2 1jA  
return sFileName; -h9#G{2W[  
} :1BM=_WwI  
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<UAP~RH{  
public void setSFileName(String value) QE6E
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{ |B|@GF?:  
sFileName = value; pU DO7Q]  
} r9;`  
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#L1>dHhat  
public int getNSplitter() FAd``9kRT  
{ x)\V lR  
return nSplitter; '{^8_k\}B  
} !Ud:?U  
>e_%M50  
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public void setNSplitter(int nCount) k1wr/G'H[  
{ 9i[4"&K  
nSplitter = nCount; ;r@!a!NLB  
} =WjJN Q  
} 5l&jPk!=  
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4zX=3iBt  
/* Q%M_   
**Utility.java Z*h ;e;  
*/ :R3P 58>  
package NetFox; #ZF>WoC@e?  
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public class Utility { o]p#%B?mZ  
w#
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public Utility() Y'&8L'2Z[  
{ rkq)&l=ny  
_2; ^v`[  
$*i7?S@~-  
} -+ko}He  
}Qb';-+;d  
//线程睡眠 ;fkSrdj  
public static void sleep(int nSecond) 9IOGc}  
{ Wv NI=>  
try{ *78)2)=~  
Thread.sleep(nSecond); 7 {nl..`  
} y-<$bA[K~  
catch(Exception e) uNg'h/^NZ|  
{ Vbo5`+NAis  
e.printStackTrace (); ])S$x{.g  
} /bi6>GaC:E  
} k~R{Y~W!!  
'hy?jQ'|e  
//日志 $59nu7yr  
public static void log(String sMsg) a0{[P$$  
{ v*vn<nPAQ>  
System.err.println(sMsg); p}&Md-$1  
} y]<#%Fh  
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hRRkFz/0&  
public static void log(int sMsg) O%prD}x  
{ W?=$V>)  
System.err.println(sMsg); 7Zo&+  
} PE|PwqX  
} zw,-.fmM#  
\a?K?v|8  
[
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/* PqVW'FYe  
**TestMethod.java Y>G*'[U  
*/ / =-6:L  
package NetFox;
(Hl8U  
&0JK38(  
Y+5"uq<'  
public class TestMethod { #n=A)#'my  
^DzL$BX  
64h_1,U  
public TestMethod() kq>GMUl~@  
{ ///xx/weblogic60b2_win.exe ](_{,P  
try{ Ny.*G@&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _yNT=#/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); luibB&p1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F. }l(KuJ  
fileFetch.start(); @81-kdTx  
} sRi?]9JIl  
catch(Exception e){e.printStackTrace ();} (*MNox?w  
B
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} c%ZeX%p  
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public static void main(String[] args) qQL.c+%L  
{ 5dqQws-,?1  
new TestMethod(); 8^8>qSD1  
} A%h~Z a  
} ]7v81G5E  
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