http断点续传简单实现（java)

/* md0=6< }P  
**SiteFileFetch.java !4E:IM63  
*/ <7GK *I  
package NetFox; jK=[   
import java.io.*; v!,O7XGH~  
import java.net.*; _KFKx3<m!  
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public class SiteFileFetch extends Thread { W.a/k7 p  
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SiteInfoBean siteInfoBean = null; //文件信息Bean sqw _c{9  
long[] nStartPos; //开始位置 l
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long[] nEndPos; //结束位置 (\}IOCNS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [Ue>KG62=  
long nFileLength; //文件长度 (]1%s?ud*  
boolean bFirst = true; //是否第一次取文件 ^tah4QmUA  
boolean bStop = false; //停止标志 zE[c$KPP  
File tmpFile; //文件下载的临时信息 (:\hor%  
DataOutputStream output; //输出到文件的输出流 6-3l6q  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2C-u2;X2  
public SiteFileFetch(SiteInfoBean bean) throws IOException d^w_rL  
{ BWs\'B  
siteInfoBean = bean; hCmOSDym  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z'fS
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d|TIrlA  
if(tmpFile.exists ()) UW+I 8\^  
{ )L{\k$r!EM  
bFirst = false; C?O{l%0  
read_nPos(); E8xXr>j>#  
} NB^.$39n  
else J=$v+8&.  
{ <ESAoY"RPN  
nStartPos = new long[bean.getNSplitter()]; 4Mprc~ 7vr  
nEndPos = new long[bean.getNSplitter()]; 3!,%;Vz=  
} {\V)bizY;  
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, ?%`Ky/  
} yaf2+zV*  
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public void run() Qu\E/T`  
{ {M$1?j"7  
//获得文件长度 ; etH)  
//分割文件 DGU$3w  
//实例FileSplitterFetch '~@WJKk  
//启动FileSplitterFetch线程 1kpI?Plki  
//等待子线程返回 /'
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try{ <W?,n%  
if(bFirst) 
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{ y>G{GQ  
nFileLength = getFileSize(); r
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if(nFileLength == -1) K|B1jdzL  
{ gs!{'=4wT  
System.err.println("File Length is not known!"); [J^,_iN[.  
} L]p:gI
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else if(nFileLength == -2) cq0jM;@d  
{ ]8mBFr5E9  
System.err.println("File is not access!"); &8;mcM//4  
} ENGw <  
else &~k/G  
{ xpV8_Gz;  
for(int i=0;i<nStartPos.length;i++) tSg#2  
{ T|E;U  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); EGs z{c[8@  
} }{lOsZA  
for(int i=0;i<nEndPos.length-1;i++) I@hC$o  
{ :g,
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nEndPos = nStartPos[i+1]; aA:Ky&5e  
} lyib+Sa ?`  
nEndPos[nEndPos.length-1] = nFileLength; ss[8d%V  
} KAe) X_R7  
} l"cYW9  
0nv3JX^l]  
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//启动子线程 nK:39D$(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )Q
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for(int i=0;i<nStartPos.length;i++) mV;7SBoT  
{ rGN-jb)T+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nB
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BjB2YO& /  
nStartPos,nEndPos,i); eZUK<&0x5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ULoTPx@N  
fileSplitterFetch.start(); .z
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} 2/;
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vj#gY2qZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4 Hu+ljdjB  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", jReI+ pS  
nEndPos = " + nFileLength); eQ*gnV}rE%  
// fileSplitterFetch[nPos.length-1].start(); /aK },+  

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//等待子线程结束 a#kZY7s  
//int count = 0; K,So#Ui  
//是否结束while循环 @ O%m,  
boolean breakWhile = false; {L8SDU{P  
sG\=_-"
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72PDqK#  
while(!bStop)  Pg`^EJ+  
{ EqOB 0\  
write_nPos(); [*1c.&%(  
Utility.sleep(500); o2jnmv~  
breakWhile = true; QZDGk4GG  
2bCa|HTv  
k_!z=6?[:  
for(int i=0;i<nStartPos.length;i++) c*3ilMP\4  
{ D0(gEb  
if(!fileSplitterFetch.bDownOver) [%b<%m}L-  
{ 87*R#((  
breakWhile = false; 1XSqgr"3  
break; |C5i3?  
} pHWol!  
} Uqkh@-6-  
if(breakWhile) *{C)o0D  
break; Q,s,EooIx  
:}E*u^v K  
'2%hc\P6P  
//count++; _/KW5  
//if(count>4) Z3S\@_/;  
// siteStop(); 6z/8nf +u  
} eqLETo@} *  
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System.err.println("文件下载结束！"); R,
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} atPf527\`  
catch(Exception e){e.printStackTrace ();} .fZv H  
} bjR&bIA:  
^goS?p/z  
@m(\f  
//获得文件长度 Ron^PvvY&  
public long getFileSize() d{YhKf#~  
{ IQH;`+  
int nFileLength = -1; 5xRh'Jkyb  
try{ wl!'Bck=  
URL url = new URL(siteInfoBean.getSSiteURL()); ;T/' CD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~kYF/B2*  
httpConnection.setRequestProperty("User-Agent","NetFox"); RRV&!<l@$  
X.JB&~/rO  
l ='lV]  
int responseCode=httpConnection.getResponseCode(); O*jNeYA  
if(responseCode>=400) p4t(xm2T  
{ BL]^+KnP  
processErrorCode(responseCode); S?D2`b  
return -2; //-2 represent access is error ^%\p; yhL  
} v}iJ:'  
s  n?  
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String sHeader; (L~3nN;rr  
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for(int i=1;;i++) Jq.26I=  
{ {Q4=GrS  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J,IOp-  
//Utility.log(in.readLine()); uD. 0?*_  
sHeader=httpConnection.getHeaderFieldKey(i); IMVoNKW-  
if(sHeader!=null) ^\x PF5  
{ gAR];(*  
if(sHeader.equals("Content-Length")) mTcLocx  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n+xM))  
break; mv+.5X  
} ph69u #Og  
}
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else L5U>`lx6$  
break; bk5~t'  
} b"x:IDW qG  
} <01MXT-  
catch(IOException e){e.printStackTrace ();} az`5{hK  
catch(Exception e){e.printStackTrace ();} 15SIZ:Q  
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Utility.log(nFileLength); sz}Nal$AC  
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return nFileLength; )L_jR%2j  
} Rov0  
6Q\n<&,{  
F=#zy#@.  
//保存下载信息（文件指针位置） QI!:+8  
private void write_nPos() #`?uV)(  
{ j^LnHVHk1  
try{ {qj>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4CNK ]2  
output.writeInt(nStartPos.length); .p0;y3so4  
for(int i=0;i<nStartPos.length;i++) Ws(BouJ  
{ ,m0=z
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// output.writeLong(nPos); po{f*}gas]  
output.writeLong(fileSplitterFetch.nStartPos); W/J3sAYv  
output.writeLong(fileSplitterFetch.nEndPos); q^,^tw  
} UY>{e>/H9  
output.close(); ncihc$V<  
} >o(*jZ  
catch(IOException e){e.printStackTrace ();} vn|X,1o  
catch(Exception e){e.printStackTrace ();} pvcf_w`n
 
} 1OJ:Vy}n  
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//读取保存的下载信息（文件指针位置） GT'%HmQI  
private void read_nPos() A(<- U|  
{ >a^H7kp  
try{ bp5hS/A^1w  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mA{gj[@:x  
int nCount = input.readInt(); .H9!UQ&It  
nStartPos = new long[nCount]; pW!]  
nEndPos = new long[nCount]; x37r{$2  
for(int i=0;i<nStartPos.length;i++) zYH6+!VBH#  
{ UIzk-.<  
nStartPos = input.readLong(); _{T`
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nEndPos = input.readLong(); 5%+T~ E*  
} Y
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input.close(); b/<4\f  
} en#W<"_"
  
catch(IOException e){e.printStackTrace ();} mb?yG:L=0b  
catch(Exception e){e.printStackTrace ();} HaLEQ73  
} A7ck-9dT/L  
60QElJ9D  
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private void processErrorCode(int nErrorCode) ~*G I<n  
{ \QYs(nm?k  
System.err.println("Error Code : " + nErrorCode); yKq;EcVx  
} ?jb7Oq#[  
$YL}rM  
Jb_/c``  
//停止文件下载 >Utn[']~  
public void siteStop() D|UDLaz~  
{ T*'5-WV|3t  
bStop = true; =g?r.;OO  
for(int i=0;i<nStartPos.length;i++) ;Q-sie(#  
fileSplitterFetch.splitterStop(); d6~wJMFl  
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} US4X CJxB  
} oSE'-8(  
//负责部分文件的抓取 @p}H@#/u\  
**FileSplitterFetch.java {T.
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*/ A:k`Ykr[  
package NetFox; JQI`9$asuC  
%M~Ugv_4v  
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import java.io.*;  M3u[E  
import java.net.*; 0(0Ep(Vj  
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public class FileSplitterFetch extends Thread { ~H?RHYP~  
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String sURL; //File URL b>;5#OQfn  
long nStartPos; //File Snippet Start Position l--xq^,`o]  
long nEndPos; //File Snippet End Position Z<xSU?J  
int nThreadID; //Thread's ID .viA+V  
boolean bDownOver = false; //Downing is over $eI[3{}X  
boolean bStop = false; //Stop identical H2rh$2  
FileAccessI fileAccessI = null; //File Access interface "xYMv"X  
;`@DQvVZ:  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lD\lFN(:
 
{ #& Rx(  
this.sURL = sURL; m_U__CZ}Tt  
this.nStartPos = nStart; g'hBs D1'  
this.nEndPos = nEnd; -%"MAIJnX  
nThreadID = id; )HR'FlxOd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p5>TL!4M  
} Sd}fse  
B*K%&w10~  
: 8(~{<R  
public void run() o"TEmZUP  
{ U
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while(nStartPos < nEndPos && !bStop) 9OP d'f  
{ -N*g|1rpa  
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try{ ^#XxqVdPk  
URL url = new URL(sURL); ;I]TM#qGF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Hm1C|Qb  
httpConnection.setRequestProperty("User-Agent","NetFox"); d$b{KyUA  
String sProperty = "bytes="+nStartPos+"-"; Yb414K  
httpConnection.setRequestProperty("RANGE",sProperty); (w4#?_  
Utility.log(sProperty); m[]pIXc(  
sK}Ru?a)  
%%klR{  
InputStream input = httpConnection.getInputStream(); Vs\)w>JF  
//logResponseHead(httpConnection); B8;_h#^q  
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h  
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byte[] b = new byte[1024]; z{;W$SO 2  
int nRead; O:pQf/Xn  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Koahd=  
{ aD24)?db-  
nStartPos += fileAccessI.write(b,0,nRead); cb|`)"<HN  
//if(nThreadID == 1) K)@]vw/\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H;Z{R@kf  
} CM8WI~  
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Utility.log("Thread " + nThreadID + " is over!"); 2 R1S>X  
bDownOver = true; j&[63XSe  
//nPos = fileAccessI.write (b,0,nRead); 4hZ-^AL"(  
} :IbrV@gN{@  
catch(Exception e){e.printStackTrace ();} tE<L4;t  
} _/P"ulNb  
} ^J\
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//打印回应的头信息 c-z=(Z  
public void logResponseHead(HttpURLConnection con) @DY0Lz;  
{ v>7tJ[s  
for(int i=1;;i++) Pr@EpO  
{ UyTq(7uo  
String header=con.getHeaderFieldKey(i); t[)z/[m  
if(header!=null) x8tRa0-q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )<IbQH|_  
Utility.log(header+" : "+con.getHeaderField(header)); =:o)+N
E  
else uh`~K6&*\w  
break; TJLz^%t  
} XlDVJx<&J  
} V>4 !fD=  
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H*;J9{  
public void splitterStop() *!'00fv  
{ SS(jjpe&,  
bStop = true; 75I*&Wl  
} {%b>/r  
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} [sACPn$f  
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kd!f/'E!  
/* i|.!*/qF  
**FileAccess.java ^ chlAQz(  
*//文件访问(定位，写) B>YrDJUN  
package NetFox; 9Ni$nZN  
import java.io.*; Ho\K %#u
 
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V +*Vi^  
public class FileAccessI implements Serializable{ $P4hNb  
YPGn8A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 BRD>q4w  
RandomAccessFile oSavedFile; aH,0+|  
long nPos; lt5~rH2  
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public FileAccessI() throws IOException x\I9J4Q  
{ B~LB^ n(>@  
this("",0); -wvJZ  
} b>Vs5nY!  
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BU]9eF!>h  
public FileAccessI(String sName,long nPos) throws IOException @*A(#U8p3  
{ O_(J',++  
oSavedFile = new RandomAccessFile(sName,"rw"); 1B,RRHXn6  
this.nPos = nPos; Kd7OnU  
oSavedFile.seek(nPos); SYa!IL-B  
} 2R:['QT  
v\$XhOK  
_pjpPS
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public synchronized int write(byte[] b,int nStart,int nLen) YC*S;q  
{ q^O{LGN  
int n = -1; %+>I1G  
try{ 9~Q.[ A  
oSavedFile.write(b,nStart,nLen); k3^S^Bv\  
n = nLen; 7Q
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} tGv4 S\  
catch(IOException e) ,i,f1XJ|  
{ 1UxRN7  
e.printStackTrace (); 7&|fD{:4U  
} b3y@!_'c  
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return n; ^J@Y?CQl\  
} [8O`VSV3  
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} xxiEL2"`>  
8~}Ti*Urc  
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/* 0Oe@0L%^3"  
**SiteInfoBean.java t4F1[P  
*/ B>|@XfPM  
package NetFox; \u",bMQF  
6dq5f?w]  
A3M)yWq  
public class SiteInfoBean { 0m51nw~B  
YujhpJ<  
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private String sSiteURL; //Site's URL %J2u+K  
private String sFilePath; //Saved File's Path YX@[z 5*  
private String sFileName; //Saved File's Name o`hF1*yp  
private int nSplitter; //Count of Splited Downloading File R &T(S
 
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public SiteInfoBean() E]_sl/`{od  
{//nSplitter的缺省值为5 
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//default value of nSplitter is 5 "mHSbG  
this("","","",5); pkBmAJb@  
} a?\ Au  
V4ayewVX  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 70*Y4'u}A  
{ (MwB%g  
sSiteURL= sURL; Q6"r^wWx  
sFilePath = sPath; I
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sFileName = sName; b[$l{RQ[?  
this.nSplitter = nSpiltter; bBC3% H^  
,58D=EgFy  
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} [ V/*{Z  
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%3'80u6BCJ  
public String getSSiteURL() b^6Ooc/-k  
{
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return sSiteURL; Hco[p+  
} M(I 2M  
g2w0#-  
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public void setSSiteURL(String value) cFD(Ap  
{ PHZA?>Q7Z  
sSiteURL = value; C+*: lLY  
} Rf2;O<  
'd0]`2tVg4  
u= !?<Q  
public String getSFilePath() &*[T
 
{ V.\do"m  
return sFilePath; iHWl%]7sN  
} A$[@AY$MI  
F0+u#/#  
]"{K5s7  
public void setSFilePath(String value) DHgEhf]  
{ qZCA16  
sFilePath = value; ZIkXy*<
(  
} |V%Qp5 XJ  
6'+3""\  
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public String getSFileName() [p[Kpunr{l  
{ O .m;a_  
return sFileName; |f?tyQ  
} 9m%[ y1v0  
b2r@vZ]D  
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public void setSFileName(String value) e ST8>r  
{ D~U4K-  
sFileName = value; 0bS\VUB(  
} %j{gZ
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;~#rdL  
public int getNSplitter() oG3>lqBwD2  
{ vfcj,1  
return nSplitter; UIovv%7zZ  
} YPFjAQ  
|SQ5Sb  
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public void setNSplitter(int nCount) aQ46e
uth  
{ Y!Wz7 C  
nSplitter = nCount; !T#~.QP4  
} ,*}SfCon  
} (7;}F~?h  
)&;?|X+p  
9JJ(KY  
/* =| %:d:r  
**Utility.java
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*/ =K-B I  
package NetFox; m9a(f>C  
Ca0~K42~  
ZlUd^6|:3  
public class Utility { A"2k,{d  
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public Utility() R<a7TkL4?  
{ RxjC sjg  
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{^1D|y  
} \%K< S  
#\GWYWkR  
//线程睡眠 a=.A/;|0*  
public static void sleep(int nSecond) "z1\I\ ^  
{ GxuFO5wz  
try{ jyb/aov  
Thread.sleep(nSecond); )F8G q,  
} r**u=q%p  
catch(Exception e) 4S`2")V  
{ Fi14_{  
e.printStackTrace (); [x kbzJ  
} #9F=+
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} j[.R|I|  
N~=p+Ow[H  
//日志 ts<5%{M(  
public static void log(String sMsg) CC;T[b&  
{ c0sU1:e0  
System.err.println(sMsg); t$m268m~  
} y9cW&rDH  
hl(M0cxEWP  
' jf$3  
public static void log(int sMsg) mg;+Th&  
{ C{`+h163\  
System.err.println(sMsg); )[.FUx  
} $8k
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} T<=Ci?C v  
)+'FTz` c  
@{_[bKg  
/* -R?~Yysd7K  
**TestMethod.java m}54yo  
*/ "7(2m  
package NetFox; d3v5^5kU  
\tc4DS  
C (L1  
public class TestMethod { _VLc1svv  
)$p<BLU  
MDZ,a0?4t  
public TestMethod() D1}Bn2BM$  
{ ///xx/weblogic60b2_win.exe Rq-BsMX!A  
try{ 9%^q?S/Rv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sOhQu>gN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Q=}p P*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5 ?~ ?8Hi  
fileFetch.start(); d9^ uEz(  
} -aK_
  
catch(Exception e){e.printStackTrace ();} 5(W`{{AW  
$p#)xx7  
\dO9nwa?  
} 52 ?TLID  
u,mC`gz  
>`R}ulz)  
public static void main(String[] args) ebxpKtEC  
{ (RW02%`jjy  
new TestMethod(); iG()"^G  
} &ejJf{id  
} !ba /]A
/  
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