http断点续传简单实现（java)

/* f ] *w1  
**SiteFileFetch.java !Dc?9W!b  
*/ P\ P=1NM  
package NetFox; =?Ry,^=b  
import java.io.*; =55)|$hgD  
import java.net.*; ])y)]H#{  
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public class SiteFileFetch extends Thread { JUw|nUnl?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )Mq4p'*A[  
long[] nStartPos; //开始位置 LT{g^g  
long[] nEndPos; //结束位置 X_-/j.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "d/54PKWx  
long nFileLength; //文件长度 T#rUbi>""  
boolean bFirst = true; //是否第一次取文件 &O+S[~  
boolean bStop = false; //停止标志 |b@`ykD  
File tmpFile; //文件下载的临时信息 tPiC?=4R  
DataOutputStream output; //输出到文件的输出流 v89tV9O)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） w\ '5lk,"  
public SiteFileFetch(SiteInfoBean bean) throws IOException M GC=L .  
{ G:+D1J]  
siteInfoBean = bean; %
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vB7]L9=@"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }c8et'HYf  
if(tmpFile.exists ())
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{ |(x%J[n0+  
bFirst = false; SgQmR#5  
read_nPos(); U{EcV%C2  
} -"Kjn`8  
else 71(ppsHk  
{ Ld:-S,2  
nStartPos = new long[bean.getNSplitter()]; a$uDoi  
nEndPos = new long[bean.getNSplitter()]; 6G4~-_  
} [D|Uwq  
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} zwUZ*Se  
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public void run() e#6H[t  
{ NB3+kf,  
//获得文件长度  [K
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//分割文件 C.=%8|Zy  
//实例FileSplitterFetch }rVLWt
 
//启动FileSplitterFetch线程 C]ho7qC  
//等待子线程返回 qzY:>>d'  
try{ sFk{Tv@Yz  
if(bFirst) 'u PI~l`g  
{ JvT#Fxjk  
nFileLength = getFileSize(); {IB4%,qT  
if(nFileLength == -1) P5XUzLV L  
{ 1(aib^!B  
System.err.println("File Length is not known!"); MkZoHzg}c  
} Xa
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else if(nFileLength == -2) yYJ +vs  
{ }+NlYD:qF  
System.err.println("File is not access!"); 29@m:=-}7  
} s*CBYzOm  
else Ki:98a$  
{ AA|G&&1y  
for(int i=0;i<nStartPos.length;i++) 9Z2aFW9  
{ =;8q`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); H-& ktQWK3  
} xjDaA U,  
for(int i=0;i<nEndPos.length-1;i++) vKbGG  
{ :d<F7`k H  
nEndPos = nStartPos[i+1]; yF XPY=EQ  
} t]t(/x#
  
nEndPos[nEndPos.length-1] = nFileLength; 'Um\m  
} <ihJp^kgQ  
} r_^
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//启动子线程 XX1Iw {o9:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; w(%$~]h  
for(int i=0;i<nStartPos.length;i++) 0a$hK9BH  
{ ewYk>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KmF+3g~#s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), k V'0r
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nStartPos,nEndPos,i); z\J#d 1e  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &C/,~pJ1S  
fileSplitterFetch.start(); o2y #Yk  
} K]U8y$^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tdi}P/x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }WNgK
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nEndPos = " + nFileLength); ]waCYrG<sY  
// fileSplitterFetch[nPos.length-1].start(); <ot%>\C  
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//等待子线程结束 g3w-Le&T  
//int count = 0; s\ ]Rgi>w  
//是否结束while循环 _l]rt  
boolean breakWhile = false; W<H^V"^  
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while(!bStop) 0j-;4>p  
{ 4mWT"T-8  
write_nPos(); q'[yYPDX5x  
Utility.sleep(500); K@=_&A!  
breakWhile = true; -QydUr/(o  
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for(int i=0;i<nStartPos.length;i++) u $T'#p1  
{ /#4BUfY f  
if(!fileSplitterFetch.bDownOver) A.S:eQvS%  
{ q1M16qv5  
breakWhile = false; }15ooe%  
break; 0'y3iar  
} c:`&QDF  
} 9y"\]G77E  
if(breakWhile) ,OO
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break; r`=!4vY2  
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//count++; cM+s)4TPL  
//if(count>4) cW, 6MAQo  
// siteStop(); R$40cW3`  
}  ^pZ\:  
=kWm9W<^  
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System.err.println("文件下载结束！"); 0 Pa\:^/6  
} RiAY>:  
catch(Exception e){e.printStackTrace ();} `Df)wNN1  
} ~%:23mIk  
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~C],?X(zk  
//获得文件长度 7b[vZNi_  
public long getFileSize() }q@Jh*  
{ ,`< [ej   
int nFileLength = -1; K1Wiiw  
try{ ijWn,bj  
URL url = new URL(siteInfoBean.getSSiteURL()); ,U/ZG|=v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j'JNQo;q  
httpConnection.setRequestProperty("User-Agent","NetFox"); DW
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int responseCode=httpConnection.getResponseCode(); ng[ZM);  
if(responseCode>=400) R`|GBVbv  
{ [2cG 7A  
processErrorCode(responseCode); sHulaX{  
return -2; //-2 represent access is error b]U%|bp  
} My!<_Hp-W  
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String sHeader; p} }=li>  
6<<i
hm+  
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for(int i=1;;i++) A#j'
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{ ff9D{$V5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >*%mJX/F  
//Utility.log(in.readLine()); [MKL>\U  
sHeader=httpConnection.getHeaderFieldKey(i); m[FH>  
if(sHeader!=null) Cuq=>J  
{ ?F9:rUyN  
if(sHeader.equals("Content-Length")) r9uuVxBD  
{ !bG%@{WT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); />zE$)'M  
break; a:tCdnK/  
} 7a}vb@  
} iWZrZ5l  
else kMz^37IFMG  
break; s`G3SE  
} KfsURTZ  
} Ojf.D6nY  
catch(IOException e){e.printStackTrace ();} ^?H3:CS  
catch(Exception e){e.printStackTrace ();} Em8C +EM  
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Utility.log(nFileLength); Rj9YAW$  
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return nFileLength; wBUn*L  
} r-s.i+\  
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//保存下载信息（文件指针位置） ch}t++`l
]  
private void write_nPos() Kuz /  
{ :!\?yj{{  
try{ B#_<?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Vs)Pg\B?  
output.writeInt(nStartPos.length); #?Z>o16,u  
for(int i=0;i<nStartPos.length;i++) rn7eY  
{ {]/}3t  
// output.writeLong(nPos); R(sPU>`MX  
output.writeLong(fileSplitterFetch.nStartPos); ?6F\cl0.  
output.writeLong(fileSplitterFetch.nEndPos); 7Rf${Wv0  
} l#_(suo64  
output.close(); wtCz%!OYB  
} P"LbWZ6Nj  
catch(IOException e){e.printStackTrace ();} 6;g"`l51  
catch(Exception e){e.printStackTrace ();} %(IkUD  
} 9"3 7va  
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//读取保存的下载信息（文件指针位置） gUs.D_*  
private void read_nPos() 0?KY
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{ T\VKNEBo  
try{ SM2
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); P\B ]><!ep  
int nCount = input.readInt(); /d*0+m8  
nStartPos = new long[nCount]; F/FUKXxx  
nEndPos = new long[nCount]; JgJ4RmH-  
for(int i=0;i<nStartPos.length;i++) 'a`cK;X9F  
{ YQWGv,47\  
nStartPos = input.readLong(); )A}u)PH4O  
nEndPos = input.readLong(); dC$z q~q  
} "#d>3M_  
input.close(); RCSG.*%%I  
} 0>?%{Xy  
catch(IOException e){e.printStackTrace ();} d|!FI/  
catch(Exception e){e.printStackTrace ();} N,
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} [=[>1<L>  
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private void processErrorCode(int nErrorCode) p0jQQg  
{ n 7Mab  
System.err.println("Error Code : " + nErrorCode); #d,+87]\=  
} ,iKL 68  
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8LI,'XZ  
//停止文件下载 1PD{m{  
public void siteStop() t'e1r&^:r~  
{ .tv'`  
bStop = true; /gWaxR*m  
for(int i=0;i<nStartPos.length;i++) 50#iC@1  
fileSplitterFetch.splitterStop(); uHj"nd13  
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} +{(f@,&~{  
} (7l'e=J0  
//负责部分文件的抓取 A}Q6DHh26  
**FileSplitterFetch.java N?Byp&rqI<  
*/ o gec6u}  
package NetFox; 5eP8nn.D  
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import java.io.*; TYv'#{  
import java.net.*; J?]wA1
 
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public class FileSplitterFetch extends Thread { cZB?_[Cp  
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String sURL; //File URL vS#Y,H:yAj  
long nStartPos; //File Snippet Start Position S{HAFrkm7  
long nEndPos; //File Snippet End Position 0wM2v[^YO  
int nThreadID; //Thread's ID c2Q KI~\x  
boolean bDownOver = false; //Downing is over q~esxp  
boolean bStop = false; //Stop identical Ass :  
FileAccessI fileAccessI = null; //File Access interface 2a=3->D&  
usj:I`>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?VUU[h8"v5  
{ k!?sHUAj  
this.sURL = sURL; b`a4SfbQS  
this.nStartPos = nStart; @|AHTf!  
this.nEndPos = nEnd; -BQoNEh  
nThreadID = id; Rcg q7W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [{iPosQWj  
} w ]8+ OP  
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public void run() HQtR;[1  
{ 52X[{  
while(nStartPos < nEndPos && !bStop) BK$cN>J  
{
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try{ 4eFqD;  
URL url = new URL(sURL); LxdF;JCz:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y~E 8z
 
httpConnection.setRequestProperty("User-Agent","NetFox"); `_YXU  
String sProperty = "bytes="+nStartPos+"-"; srzlr-J  
httpConnection.setRequestProperty("RANGE",sProperty); $('"0 @fg  
Utility.log(sProperty); /b&ka&|t  
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InputStream input = httpConnection.getInputStream(); &>nB@SQZ  
//logResponseHead(httpConnection); |ry![\  
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byte[] b = new byte[1024]; k4N_Pa$}\  
int nRead; E?v9c>c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,> Ya%;h2k  
{ zR@4Z>6   
nStartPos += fileAccessI.write(b,0,nRead); azhilUD8  
//if(nThreadID == 1) v11Uw?CM  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~F [V  
} %C[#:>'+  
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Utility.log("Thread " + nThreadID + " is over!"); DT;n)7+,  
bDownOver = true; ;H' ,PjU  
//nPos = fileAccessI.write (b,0,nRead); _*l+ze[a  
} >Hr&F nh+  
catch(Exception e){e.printStackTrace ();} ~ 3!yd0[k  
} hs;YMUA"  
} :)9CG!2y<M  
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//打印回应的头信息 <z.Y#{p?k  
public void logResponseHead(HttpURLConnection con) b=L4A,w~a  
{ Z=+Tw!wR>  
for(int i=1;;i++) @23?II$=@  
{ I K9plsd*  
String header=con.getHeaderFieldKey(i); Oj=g;iY  
if(header!=null) wZUZ"Y}9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $.Ia;YBf  
Utility.log(header+" : "+con.getHeaderField(header)); SO|!x}GfI  
else 
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break; fw&cv9X(IU  
} F 
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} wiFA3_\G  
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public void splitterStop() po! [Nd&"  
{ uVth&4dh9  
bStop = true; QbJE+m5  
} }j)][{i*x  
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} BT^Im=A  
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/* lRANXM  
**FileAccess.java /Moyn"Kj{  
*//文件访问(定位，写) v)j3YhY  
package NetFox; H'"=C&D~  
import java.io.*; `_iK`^(-  
" k0gZb  
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public class FileAccessI implements Serializable{ ]."t  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r9Vt}]$aG  
RandomAccessFile oSavedFile; $jg~a  
long nPos; ]>/oo
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public FileAccessI() throws IOException swz)gh-*  
{ 5E#8F  
this("",0); 
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} &c^tJ-s  
\zJb}NbnT  
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public FileAccessI(String sName,long nPos) throws IOException r0Zj'F_e  
{ C14"lB.  
oSavedFile = new RandomAccessFile(sName,"rw"); 3o2x&v  
this.nPos = nPos; 84_Y+_9  
oSavedFile.seek(nPos); *kt|CXxAS8  
} *qA:%m3  
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public synchronized int write(byte[] b,int nStart,int nLen) :sS4T&@1=  
{ E{'Y>gB6  
int n = -1; }U^i
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try{ Xf;_r+;  
oSavedFile.write(b,nStart,nLen); mwMcAUD]2  
n = nLen; ,`ba?O?*G  
} ?>
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catch(IOException e) i'B$Xr  
{ Ou_2UT  
e.printStackTrace (); Obx!>mI^6  
} @rv)J[7Y&  
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return n; v*kX?J#]5  
} g;7W%v5wqk  
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} G|I}x/X"Q7  
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/* ,z01*Yx  
**SiteInfoBean.java x21XzGLY|}  
*/ GMY[Gd  
package NetFox; <Zo{D |hW  
@dn&M9Z  
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public class SiteInfoBean { 6"9(ce KX  
K}
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private String sSiteURL; //Site's URL .)E1|U[L  
private String sFilePath; //Saved File's Path a`D`v5G t  
private String sFileName; //Saved File's Name 7ju^
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private int nSplitter; //Count of Splited Downloading File w5vzj%6i  
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public SiteInfoBean() GF36G?iEi  
{//nSplitter的缺省值为5 5,BvT>zFY  
//default value of nSplitter is 5 KP`Pzx   
this("","","",5); O<J
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} 5S ) N&%  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~ %Ij5PD  
{ Z6
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sSiteURL= sURL; FP")$ ,=s  
sFilePath = sPath; Q?bC'147O  
sFileName = sName; hG}
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this.nSplitter = nSpiltter; n0)y|B#  
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>x]ir  
} 8yybZ@  
R*H-QH/H1  
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public String getSSiteURL() `*xSn+wL`_  
{ <Wd_m?z  
return sSiteURL; " eS-i@  
} Z?qc4Cg  
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public void setSSiteURL(String value) @W=:r/  
{ I5]58Ohx  
sSiteURL = value; Qnx?5R-}ZU  
} xiVbVr#[  
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public String getSFilePath()
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{ dFZh1*1  
return sFilePath; z"*3p8N  
} u63Q<P<  
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public void setSFilePath(String value) `69xR[f  
{  `ghNS  
sFilePath = value; !>WW(n07Ma  
} H{uR+&<  
,nWZJ&B  
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public String getSFileName() U%KgLg#  
{ [4-u{Tu  
return sFileName; JmuoYlf|  
} g@m__   
@2eH;?uO  
/S9n!H:MT  
public void setSFileName(String value) &-KQ m20n  
{ {~V_6wY g  
sFileName = value; X=VaBy4#  
} 4rypT-%^;  
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public int getNSplitter() '<h@h*R  
{ ^oEaE#I  
return nSplitter; ~g *`E!2  
} /+m7
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public void setNSplitter(int nCount) 2\#
~%D>[  
{ xw3A|Aj?r  
nSplitter = nCount; XeozRfk%J|  
} 787}s`,}  
} { /Gm|*e{  
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/* ^3nB2G.ax  
**Utility.java 6MbMAh5>  
*/ OKCX>'j:S  
package NetFox; [ZETyM`  
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public class Utility { [[
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public Utility() aT=V/Xh}d  
{ ScC!?rTW~7  
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} {6*{P!H  
u"zQh|  
//线程睡眠 BtP*R,>  
public static void sleep(int nSecond) [,qb) &_  
{ DO? bJ01  
try{ =e]Wt
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Thread.sleep(nSecond); ]K%D$x{+\  
} Ay\!ohIS3  
catch(Exception e) Mp^U)S+  
{ nHB`<B  
e.printStackTrace (); yXA]E.K!  
} Xqas[:)7+  
} V__n9L/t  
wqp(E+&  
//日志 tA9(N>[*  
public static void log(String sMsg) 1;9 %L@  
{ CYC6:g|)  
System.err.println(sMsg); Oxf,2r  
} h_h6@/1l  
0"M0tA#  
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public static void log(int sMsg) (9D,Ukw  
{ 3yIC@>&y(8  
System.err.println(sMsg); ,6a }l;lv  
} d*<goBd  
} hH@pA:`s  
+yu^Z*_  
|y7#D9m  
/* %LZf=`:(  
**TestMethod.java ;?:X_C  
*/  ?ik6kWI  
package NetFox; x20s
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f5QJj<@  
public class TestMethod { {~:F1J~=  
VUGVIy.  
mH09* Z  
public TestMethod() %D}]Z=gp  
{ ///xx/weblogic60b2_win.exe g,cl|]/\d  
try{ h3
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |CjE}5Op>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  W,)qE^+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5VPP 2;J  
fileFetch.start(); GGchNt  
} pxs`g&3yd  
catch(Exception e){e.printStackTrace ();} eEkbD"Q  
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} D*#r V P  
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public static void main(String[] args) ni x1_Wo;  
{ &tE#1<k  
new TestMethod(); OQh(qa  
} Cdd +I5~  
} 5%6r,?/7KM  
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