http断点续传简单实现（java)

/* LL_@nvu}M  
**SiteFileFetch.java +7mUX  
*/ ~='}(Fg:  
package NetFox; v[\Z^pccgj  
import java.io.*; XE$;Z'Qhjm  
import java.net.*; %%T?LRv  
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public class SiteFileFetch extends Thread { +[` )t/  
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" V4@nv  
SiteInfoBean siteInfoBean = null; //文件信息Bean N5b^  
long[] nStartPos; //开始位置 'x,6t66*"l  
long[] nEndPos; //结束位置 hiEosI C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5p>rQq0  
long nFileLength; //文件长度 ;--p/h*.  
boolean bFirst = true; //是否第一次取文件 Hbl&)!I  
boolean bStop = false; //停止标志 .1f!w!ltVR  
File tmpFile; //文件下载的临时信息 7po;*?Ox  
DataOutputStream output; //输出到文件的输出流 \HL66%b[  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Fu>;hx]s  
public SiteFileFetch(SiteInfoBean bean) throws IOException T[- %b9h>  
{ ;qs^+  
siteInfoBean = bean; >-j(
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); XG!^[ZDs  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .umN>/o[  
if(tmpFile.exists ()) [M2xF<r6t  
{ ]zz%gZz  
bFirst = false; )Vo%}g?6!  
read_nPos(); ul{D)zm\D  
} XZ"oOE0=  
else >?jmeD3u  
{ D^S"6v"z  
nStartPos = new long[bean.getNSplitter()]; (@NW
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nEndPos = new long[bean.getNSplitter()]; c1xX)cF  
} }Xb|Ur43  
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} E%?> %h  
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public void run() +4F; m_G6  
{ _^D-nk?  
//获得文件长度 rX22%~1  
//分割文件 LX}|%- iv  
//实例FileSplitterFetch y*E{X  
//启动FileSplitterFetch线程 G_}oI|B  
//等待子线程返回 44pVZ5c  
try{ `_x#`%!#2  
if(bFirst) mr,GHx  
{ MhjIE<OI=  
nFileLength = getFileSize(); +I@2,T(eG  
if(nFileLength == -1) 75iudki  
{ {<zE}7/2-  
System.err.println("File Length is not known!"); wj8\eK)]L  
} BkB9u&s^  
else if(nFileLength == -2) "?6R"Vk?:  
{
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System.err.println("File is not access!"); OI:T#uk5  
} On}b|ev  
else |M EJ)LE7  
{ @h\i<sh!^  
for(int i=0;i<nStartPos.length;i++) E)]emeGd  
{ 4'.]-u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -|
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} 
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for(int i=0;i<nEndPos.length-1;i++) KVHK~Y-G  
{ 1pqYB]*u_  
nEndPos = nStartPos[i+1]; P0rdGf 5T  
} *-'`Ea  
nEndPos[nEndPos.length-1] = nFileLength; oJZ0{^  
} bd3>IWihp  
} #fFD|q  
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3  
X^C $|:  
//启动子线程 @h5Q?I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^y~oXS(  
for(int i=0;i<nStartPos.length;i++) 3*R(&O6}  
{ n65fT+;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JEfhr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _+gpdQq\p  
nStartPos,nEndPos,i); Up>,~bs]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #+^l3hMK  
fileSplitterFetch.start(); )5TX3#=;(G  
} (A;HB@)[A  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]@qD4:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [n +(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cGWL'r)P  
nEndPos = " + nFileLength); ?h8/\~Dw  
// fileSplitterFetch[nPos.length-1].start(); P.~sNd oJ  
{h;i x  
&A^2hPe}  
//等待子线程结束 7>gW2m  
//int count = 0; Si|8xq$E;  
//是否结束while循环 t5QGXj  
boolean breakWhile = false; FYK}AR<=  
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while(!bStop) Q8
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{ /Wy9".  
write_nPos(); (; Zl  
Utility.sleep(500); B,Jn.YX  
breakWhile = true; l4OPzNc'  
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for(int i=0;i<nStartPos.length;i++) R xWD>:  
{ }Ub "Vb  
if(!fileSplitterFetch.bDownOver) n4zns,:)/  
{ os(}X(   
breakWhile = false; tdC kvVE  
break; XB%`5wwd  
} * =O@D2g0  
} gKb5W094@  
if(breakWhile) *oIKddZh  
break; h#8{fr)6  
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bre6SP@  
//count++; :Czvwp{z  
//if(count>4) VE/~tT;  
// siteStop(); 1xwq:vFC.  
} *OZO} i  
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System.err.println("文件下载结束！"); gOk^("@  
} n6*; ~h5  
catch(Exception e){e.printStackTrace ();} q5w)i  
} /h@rLJ)o>  
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//获得文件长度 yNQ 9~P2  
public long getFileSize() ^[zF IO  
{ Pq( )2B  
int nFileLength = -1; {K2F(kz?T  
try{ "2@Ys*e  
URL url = new URL(siteInfoBean.getSSiteURL()); n]btazM{   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); POQ1K O  
httpConnection.setRequestProperty("User-Agent","NetFox"); LZu_-I  
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int responseCode=httpConnection.getResponseCode(); M~!LjJg;  
if(responseCode>=400) @yjui  
{ ;Y16I#?;Kh  
processErrorCode(responseCode); t,;b*ZR  
return -2; //-2 represent access is error 2qkC{klC^M  
} o6;VrpaNi  
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String sHeader; U0S}O(Ptr  
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for(int i=1;;i++) 6d/b*,4[  
{ fmq^AnKd  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); FkT% -I  
//Utility.log(in.readLine()); 4HDQj]z/  
sHeader=httpConnection.getHeaderFieldKey(i); dzMI5fA<_  
if(sHeader!=null) 4^B:Q9B)  
{ Py,@or7n  
if(sHeader.equals("Content-Length")) ?jzadCel  
{ *'(dcy9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x9CI>l  
break; wwmODw<tT  
} DSHpM/7  
} 5*>3(U  
else
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break; XC{(O:EG  
} ( ]o6Pi  
} Afa{f}st  
catch(IOException e){e.printStackTrace ();} JXnPKAN  
catch(Exception e){e.printStackTrace ();} B[MZPv)  
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Utility.log(nFileLength); JGD{cr[S  
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return nFileLength; HIeMV,.QN  
} }Mo9r4}  
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//保存下载信息（文件指针位置） "Hjw  
private void write_nPos() Vt
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{ 3B"rI  
try{ \>/:@4oK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); V2]S{!p}k  
output.writeInt(nStartPos.length); "WYcw\@U  
for(int i=0;i<nStartPos.length;i++) +CNRSq"  
{ I.e'  
// output.writeLong(nPos); 0KT{K(  
output.writeLong(fileSplitterFetch.nStartPos); c\4n7m,y  
output.writeLong(fileSplitterFetch.nEndPos); iVu+ct-iv  
} z?"5="D  
output.close(); HNuwq\w  
} J0p,P.G  
catch(IOException e){e.printStackTrace ();} %dT%r=%Y  
catch(Exception e){e.printStackTrace ();} Pjb9FCA'  
} Azz]TO  
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xD?{Hw>QT#  
//读取保存的下载信息（文件指针位置） /9w}[y*E  
private void read_nPos() |H_)u  
{

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try{ d8RpL{9\7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p go\(K0  
int nCount = input.readInt(); Z#o
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nStartPos = new long[nCount]; iK%Rq  
nEndPos = new long[nCount]; X0Oq lAw  
for(int i=0;i<nStartPos.length;i++) r IK|}5  
{ ZJ[ Uz_%W  
nStartPos = input.readLong(); nLfnikw&  
nEndPos = input.readLong(); *E)Y?9u"  
} F<(xz=  
input.close(); A
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} -6tF   
catch(IOException e){e.printStackTrace ();} x(7K3(#|  
catch(Exception e){e.printStackTrace ();} H@j^,  
} b);}x1L.T  
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}lb.3fqiA  
private void processErrorCode(int nErrorCode) \+AH>I;vO  
{ 5PL,~Y  
System.err.println("Error Code : " + nErrorCode); n ~3c<{coZ  
} YKc{P"'/|  
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 xBG1up<z  
//停止文件下载 dw4)4_  
public void siteStop() +tN-X'u##  
{ "&+0jfLY+  
bStop = true; (P>vI'  
for(int i=0;i<nStartPos.length;i++) +%Gm2e;_u  
fileSplitterFetch.splitterStop(); z"O-d<U5  
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} Nb9pdkf0  
} )w`Nkx  
//负责部分文件的抓取 3z#;0n
}  
**FileSplitterFetch.java V7@xr M  
*/ +{w&ksk  
package NetFox; SA7,]&Zb  
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import java.io.*; /&dt!.WY^  
import java.net.*; <C{5(=
X{  
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public class FileSplitterFetch extends Thread { tj&A@\/  
=
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String sURL; //File URL M#>GU<4"  
long nStartPos; //File Snippet Start Position } 
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long nEndPos; //File Snippet End Position W[m_IY  
int nThreadID; //Thread's ID dCK-"#T!  
boolean bDownOver = false; //Downing is over HY:@=%R  
boolean bStop = false; //Stop identical |#B"j1D,H  
FileAccessI fileAccessI = null; //File Access interface T:&+#0<  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e](=)h|  
{ ,{50zx2  
this.sURL = sURL; <XagkD  
this.nStartPos = nStart; o%5bg(  
this.nEndPos = nEnd; 4dK@UN\  
nThreadID = id; K]oPh:E  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ] 6gu  
} rh_({rvQ  

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public void run() ;hvXFU  
{ ckk[n  
while(nStartPos < nEndPos && !bStop) 7GUJ&U)J  
{ ?:nZv< x  
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try{ kt#W~n  
URL url = new URL(sURL); h,+=h;!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D=>^m=?0  
httpConnection.setRequestProperty("User-Agent","NetFox"); Em;b,x*U  
String sProperty = "bytes="+nStartPos+"-"; ]`XuE-Uh  
httpConnection.setRequestProperty("RANGE",sProperty); zOOX>3^  
Utility.log(sProperty); iFA"m;$  
,lJ6"J\8.  
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InputStream input = httpConnection.getInputStream(); &3f.78a  
//logResponseHead(httpConnection); dmy-}.pqN  
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byte[] b = new byte[1024]; Mg$9'a"[\
 
int nRead; (r4VIlap  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) uLM_KZ  
{ +CT$/k  
nStartPos += fileAccessI.write(b,0,nRead); Fc~w`~tv  
//if(nThreadID == 1) H=#Jg;_w  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }A7qIys$4  
} /8>/"Z2S  
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[BBKj)IK  
Utility.log("Thread " + nThreadID + " is over!"); a
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bDownOver = true; e;5Lv9?C8  
//nPos = fileAccessI.write (b,0,nRead); rk|(BA  
} b2e  a0  
catch(Exception e){e.printStackTrace ();} )1
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} u&XkbPZ%4c  
} |q2lTbJ  
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WN#lfn8 7  
//打印回应的头信息 #L0I+ K,K\  
public void logResponseHead(HttpURLConnection con) I uj=d~|>  
{ 77d`N  
for(int i=1;;i++) `Qf :PX3  
{ \cP'#jZz  
String header=con.getHeaderFieldKey(i); R TUNha^<T  
if(header!=null) p8dn-4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y0\\(0j64  
Utility.log(header+" : "+con.getHeaderField(header)); Td1ba^J  
else *v ^"4  
break; Sp,Q,Q4  
} O + & xb  
} !(K{*7|h  
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public void splitterStop() oB R(7U~0  
{
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bStop = true; Zw][c7%  
} x,gE$dNzy  
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} &vX!7Y  
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/* ~h
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**FileAccess.java m8j-lNu  
*//文件访问(定位，写) H#6^-6;/  
package NetFox; .Pes{uHg  
import java.io.*; ;sR6dT)  
?_>^<1I1  
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public class FileAccessI implements Serializable{ n qLAby_  
-5v.1y=!L  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 gQ=POJ=G  
RandomAccessFile oSavedFile; S<!_ uq  
long nPos; |zq!CLjD@  
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public FileAccessI() throws IOException }K80G~O2<  
{ ^Lmc%y  
this("",0); C'czXZtn  
} 2{B(j&{  
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81%qM7v9H  
public FileAccessI(String sName,long nPos) throws IOException _"FbjQ"  
{ dK-  ^  
oSavedFile = new RandomAccessFile(sName,"rw"); :~qtvs;{  
this.nPos = nPos; ?(|TP^  
oSavedFile.seek(nPos); 9OO0Ht4j  
} i75?*ld  
`"^@[1  
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public synchronized int write(byte[] b,int nStart,int nLen) Cv?<}q  
{ S|
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int n = -1; =X%R*~!#Of  
try{ ~]m@k'n  
oSavedFile.write(b,nStart,nLen); dd @COP?  
n = nLen; +w_MSj#P  
} ~0Q\Lp);  
catch(IOException e) :c+a-Py $E  
{ N`L' 4v)  
e.printStackTrace (); ZipK;!9by  
} VLwJ6?.f'  
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Y;%R/OyWY  
return n; PEwW*4Xo  
} }(vOaD|k=  
{U+9,6.`  
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} ,i$(yx?  
)KT
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i85+p2i7  
/* hz>yv@1  
**SiteInfoBean.java Rzn0-cG  
*/ 8gu7f;H/k  
package NetFox; 
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F(J!dG5#  
%'D:bi5  
public class SiteInfoBean { 4p/V6kr&r  
t0AqGrn  
$HR(|{piZ  
private String sSiteURL; //Site's URL "8C(_z+]K`  
private String sFilePath; //Saved File's Path k*UR#z(I  
private String sFileName; //Saved File's Name :BrnRW64  
private int nSplitter; //Count of Splited Downloading File ^QHMN 7r/  
2kmna/Qa6  
sL[(cX?;2  
public SiteInfoBean() j_YZ(: =  
{//nSplitter的缺省值为5 5D02%U2N)G  
//default value of nSplitter is 5 G3^n_]Jb  
this("","","",5); wTgx(LtH  
} Vms7 Jay  
a\HtxR8L  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V=8{CmqT  
{ w!GU~0~3[  
sSiteURL= sURL; [b)K@Ha  
sFilePath = sPath; 5
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sFileName = sName; RE*S7[ge  
this.nSplitter = nSpiltter; Ms$7E  
m= beB\=  
_QtQPK\+  
} s'fcAh,c6  
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public String getSSiteURL() d9e H}#OY  
{ JwG5#CFu^  
return sSiteURL; e^l+#^fR  
} N4GIb 6  

uzn))/"  
/EAQ.vxI  
public void setSSiteURL(String value) l8n[8AT1  
{ 6[Pr<4J  
sSiteURL = value; %_X[{(  
} =w>>7u$4  

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public String getSFilePath() m#}{"d&J  
{ M6>
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return sFilePath; /-<m(72wF  
} n*8RYm)?  
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4>ce,*B1  
public void setSFilePath(String value) b<8J;u<  
{ KX`nHu;  
sFilePath = value; Qre&N_  
} tZ{q\+h  
KL_}:O68  
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public String getSFileName() 5t1DB'K9$_  
{ 5<GRi"7A@  
return sFileName; gSo(PW)  
} I`}vdX)  
EA{*%9 A  
h,jAtL!  
public void setSFileName(String value) q-)_Qco  
{ o4 OEA)k)=  
sFileName = value; Y Z2VP  
} j!8+|eAkk  
{,mRMDEy  
v}*u[GWl]  
public int getNSplitter() N)I T?  
{ lL+^n~g  
return nSplitter; TXOW/{B  
} M>z7H"jCu  
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B+H9c~3$  
public void setNSplitter(int nCount) r
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{ \rnG 1o  
nSplitter = nCount; FoXQ]X7"  
} g4qdm{BL  
} xwp?2,<  
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/* qO3BQ]UF  
**Utility.java ^E?V+3mV  
*/ 4 AmF^H  
package NetFox; jHw2Q8s|R  
A-`J!xj#/  

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public class Utility { ~acK$.#  
B91PlM.  
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public Utility() A =#-u&l  
{ ?{P6AF-xcf  
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} e(% Solkm?  
Qi]Z)v{^  
//线程睡眠 cTx/Y&\9  
public static void sleep(int nSecond) 6 &Aa b56  
{ o[W3/  
try{ g-gBg\y{v  
Thread.sleep(nSecond); cZT.vA#  
} 9F1stT0G%  
catch(Exception e) |VEAzY|[#  
{ 2/q=l
?  
e.printStackTrace (); ]<z(Rmn`Q  
} ffd3QQ  
} ]c=1-Rl
  
nL20}"$E  
//日志 O;t?@!_  
public static void log(String sMsg) G6bg ~V5Q:  
{ R*fR?  
System.err.println(sMsg); myX0<j3G5  
} >^HTghgRD  
w:+#,,rwzV  
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public static void log(int sMsg) E}j8p_p  
{ zFQkUgb  
System.err.println(sMsg); Y rnqi-P  
} |^{" 2l"j  
} u(`A?H:  
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]7 mSM  
/* ~,-O  
**TestMethod.java ^#nWgo7{7  
*/ )#B
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package NetFox; }@6 %yR  
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2/N*Uk 0  
public class TestMethod { F;@&uXYgc  
l;kZS  
P;/wb/  
public TestMethod() %-|q3 ^s  
{ ///xx/weblogic60b2_win.exe DN0b.*[`3  
try{ Sylsp%A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6+#cyKj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); oF^hq-xcP  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,
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fileFetch.start(); +Z]%@"S?  
} DQnWLC"u  
catch(Exception e){e.printStackTrace ();} !\4FIs&Qv  
Bz~h-  
s\R?@  
} t+q`h3
 
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public static void main(String[] args) zD-8#H35X"  
{ PaJwM%s)L  
new TestMethod(); b<7qmg3  
} 3<V!y&a  
} #_\~Vrf(#  
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