http断点续传简单实现（java)

/* ZUPlMHc  
**SiteFileFetch.java V~([{
 
*/ N{w)}me[YY  
package NetFox; .sCi9d WR  
import java.io.*; V/"P};n  
import java.net.*; ancs  
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I@ "%iYL  
public class SiteFileFetch extends Thread { ?Zu2=<DU  
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SiteInfoBean siteInfoBean = null; //文件信息Bean HuzHXn)  
long[] nStartPos; //开始位置 `tZm  
long[] nEndPos; //结束位置 (CDwl,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 IWc?E  
long nFileLength; //文件长度 x=]PE}<E  
boolean bFirst = true; //是否第一次取文件 `_M*2(rt  
boolean bStop = false; //停止标志 W{'RR.
  
File tmpFile; //文件下载的临时信息 !0p_s;uu,W  
DataOutputStream output; //输出到文件的输出流 t|XQFb@}  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 98O0M#|d  
public SiteFileFetch(SiteInfoBean bean) throws IOException vG;)(.:  
{ *>"k/XUn$  
siteInfoBean = bean; a8$gXX-2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); R{N9'2l:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); yCC.j%@  
if(tmpFile.exists ()) NWx.l8G  
{ c0}* $e  
bFirst = false; :s(vn Ie^  
read_nPos(); afE`GG-  
} gN./u   
else N!RkV\:X  
{ uj 6dP  
nStartPos = new long[bean.getNSplitter()]; )}`3haG  
nEndPos = new long[bean.getNSplitter()]; 4Og&w]  
} 9'tOF  
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} AiMD"7 )c  
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public void run() 0qND2_  
{ k#*tf:
R  
//获得文件长度 q].n1w[  
//分割文件 &tKr ?l  
//实例FileSplitterFetch Jng,:$sZ  
//启动FileSplitterFetch线程 UM?{ba9  
//等待子线程返回 C
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try{ TttD}`\.  
if(bFirst) yDk|ad|  
{  ^##tk
  
nFileLength = getFileSize(); lL6bIjf  
if(nFileLength == -1) dM|&Y6
  
{ F%<hng%k  
System.err.println("File Length is not known!"); P8Nzz(JF  
} *C>B-j$  
else if(nFileLength == -2) Ry5/O?QL  
{ `F)Q=  
System.err.println("File is not access!"); g8I=s7cnb  
} y:\ ^[y IQ  
else zQ[g*  
{ qJ\tc\
  
for(int i=0;i<nStartPos.length;i++) o'9K8q\1  
{ N|G=n9p  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DBUhqRfl  
} mn5
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for(int i=0;i<nEndPos.length-1;i++) M@
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{ !kzC1U  
nEndPos = nStartPos[i+1]; 86.LkwlqoH  
} xUp[)B6?:  
nEndPos[nEndPos.length-1] = nFileLength; D'dE!CAUs  
} *TacVp  
} N;)Y+amg^  
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//启动子线程 ?k6PH"M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >o\s'i[  
for(int i=0;i<nStartPos.length;i++) fWr6f`de  
{ }=d]ke9_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +Xa^3 =B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %&D,|Yl6  
nStartPos,nEndPos,i); N{lj"C]L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $-Ud&sjn  
fileSplitterFetch.start(); LdSBNg#3  
} ^\Bm5QkS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]}K\
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); BseK?`]U"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %]~XbO  
nEndPos = " + nFileLength); K2=`.  
// fileSplitterFetch[nPos.length-1].start(); pI__<  
l?_h(Cq<  
'/Y D$*,  
//等待子线程结束 j_r?4k
 
//int count = 0; _;8aiZt|u  
//是否结束while循环 "X\|!Mxh  
boolean breakWhile = false; f^ q0#+k)  
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@@
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while(!bStop) h"mG\xi  
{ Y Me
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write_nPos(); l~f>ve|  
Utility.sleep(500); BE&P/~(C  
breakWhile = true; I=N;F6  
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for(int i=0;i<nStartPos.length;i++) d+ LEi^  
{ %SWtE5HZQq  
if(!fileSplitterFetch.bDownOver) [31vx0$_p  
{ ^qs{Cf$  
breakWhile = false; A7{l60(5  
break; 4v@urW s  
} R"j6 w[tn  
} $
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if(breakWhile) _`Ojh0@00  
break; ^uU'Qc4S=  
<NIg`B@'s  
/7EeM{,~  
//count++; o6H\JCne  
//if(count>4) c5>'1L  
// siteStop(); ]6W;~w%  
} F vJJpPS  
(}$~)f#s  
6mawcK:7  
System.err.println("文件下载结束！"); "E? 8.`T  
} )gO=5_^u*o  
catch(Exception e){e.printStackTrace ();} >a5M:s)  
} >e]46K  
%]>LnbM>4  
@iC,0AK4k  
//获得文件长度 ~:65e 8K  
public long getFileSize() ?J;*  
{ x#mZSSd  
int nFileLength = -1; SC'F,!  
try{ gq$]jWtCD  
URL url = new URL(siteInfoBean.getSSiteURL()); 9J"Y   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r#Pkhut  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?*I _'2  
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int responseCode=httpConnection.getResponseCode();  T?!&a0  
if(responseCode>=400)
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{ v-*CE[  
processErrorCode(responseCode); +y+-~;5iv  
return -2; //-2 represent access is error \u|8MEB  
} i-Le&  
fO!S^<9,-  
#3:;&@#  
String sHeader; ]Q}z-U  
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9!XW):  
for(int i=1;;i++) S-FoyID\H  
{ >[4;K&$B  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <K8$00l
m  
//Utility.log(in.readLine()); ` ,B&oV>  
sHeader=httpConnection.getHeaderFieldKey(i); e/;1<5tfj  
if(sHeader!=null) 4o:
  
{ 8&AHu  
if(sHeader.equals("Content-Length")) 8}Pd- .se  
{ fk(l.A$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4:!KtpR[O  
break; #8N9@  
} !fFmQ\|)4S  
} "}uPz4  
else !Ua74C
 
break; R~-r8dWcw  
} {.W$<y (j7  
} e`1,jt'  
catch(IOException e){e.printStackTrace ();} %cM2;a=2  
catch(Exception e){e.printStackTrace ();} !ul)e;a  
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Utility.log(nFileLength); M2[ywab  
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return nFileLength; st;.Po[h  
} Fm\ h883\  
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//保存下载信息（文件指针位置） #S[:Q.0 ;  
private void write_nPos() 1goK>=-^  
{ J~Gq#C^e  
try{ h[()!\vBy  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `jR= X  
output.writeInt(nStartPos.length); URW#nm?  
for(int i=0;i<nStartPos.length;i++) &hmyfH&S  
{ c;,jb  
// output.writeLong(nPos); C9-90,  
output.writeLong(fileSplitterFetch.nStartPos); {5+t\~q$  
output.writeLong(fileSplitterFetch.nEndPos); z3IQPl^  
} aX=  
output.close(); uJ S+;H  
} jW6~^>S  
catch(IOException e){e.printStackTrace ();} A9lnQCsJ  
catch(Exception e){e.printStackTrace ();} S
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} xUYUOyV  
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Y(WX`\M97  
//读取保存的下载信息（文件指针位置） YoD1\a|  
private void read_nPos() cad%:%p  
{ Ez^U1KKOE7  
try{ /*Z,i&eC  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); saOXbt(&  
int nCount = input.readInt(); u1yc  
nStartPos = new long[nCount]; A"S{W^iL  
nEndPos = new long[nCount]; ]Mv.Rul?~  
for(int i=0;i<nStartPos.length;i++) dMsX}=EI<  
{ zosJ=$L  
nStartPos = input.readLong(); *Yk3y-   
nEndPos = input.readLong(); w{[OtGIi3  
} pCSR^ua>  
input.close(); 7Rr(YoWa  
} /}?"O~5M"  
catch(IOException e){e.printStackTrace ();}  R1'bB"$  
catch(Exception e){e.printStackTrace ();} ]}/LNO*L"  
} ,HXY|fYr  
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private void processErrorCode(int nErrorCode) wU_e/+0h  
{ pg69mKZ$  
System.err.println("Error Code : " + nErrorCode); Qcu1&t\C  
} P@'<OI  
RE]u2R6Y  
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//停止文件下载 }E$^!q{  
public void siteStop() |+//pGx  
{ X}`|"NIk.  
bStop = true; 3O<:eS~  
for(int i=0;i<nStartPos.length;i++) `[V]xP%V  
fileSplitterFetch.splitterStop();  +Io^U  
))}w;w  
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} oB8u[!  
} iXtar;%  
//负责部分文件的抓取 |`9POl=  
**FileSplitterFetch.java =LHE_ AA  
*/ BnH<-n_  
package NetFox; ?DEj| i8  
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import java.io.*;
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import java.net.*; 8$<jd^w  
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public class FileSplitterFetch extends Thread { 2.O
;  
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String sURL; //File URL hKb-l`KO  
long nStartPos; //File Snippet Start Position 9J_lxy}  
long nEndPos; //File Snippet End Position X b-q:{r1h  
int nThreadID; //Thread's ID A P><l@  
boolean bDownOver = false; //Downing is over G"0YCi#I|  
boolean bStop = false; //Stop identical `,~I*}T>5W  
FileAccessI fileAccessI = null; //File Access interface Kx?3]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [Y.3miE  
{ P6*IR|  
this.sURL = sURL; yhQv $D,^f  
this.nStartPos = nStart; |cL'4I>b9  
this.nEndPos = nEnd; tF SO"  
nThreadID = id; %..{c#V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H27_T]\  
} TI:-Y@8  
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public void run() +N2?fgA  
{ dK,j|  
while(nStartPos < nEndPos && !bStop) 0EfM~u  
{ ,g%2-#L%  
{E!ie{~  
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try{ DLe?@R5  
URL url = new URL(sURL); j
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'E+Ty(ED5  
httpConnection.setRequestProperty("User-Agent","NetFox"); TYW$=p|  
String sProperty = "bytes="+nStartPos+"-"; W!4(EdT*Cq  
httpConnection.setRequestProperty("RANGE",sProperty); ; k{w@L.@  
Utility.log(sProperty); TTpK8cC  
#R<4K0Xan  
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InputStream input = httpConnection.getInputStream(); \D>vdn"Lx  
//logResponseHead(httpConnection); l)GV&V  
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Az
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byte[] b = new byte[1024]; !vHUe*1a{  
int nRead; Q+gd|^Vc9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1 *'SP6g  
{ U
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nStartPos += fileAccessI.write(b,0,nRead);  )]L:OE  
//if(nThreadID == 1) IZBU<1M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ej>5PXp'2  
} l'HrU 1_7Y  
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Utility.log("Thread " + nThreadID + " is over!"); ENm\1  
bDownOver = true; vs;T}'O  
//nPos = fileAccessI.write (b,0,nRead); v.H00}[.  
} 6"C$]kF?  
catch(Exception e){e.printStackTrace ();} }Wjb0V  
} OoTMvZ
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} L}lOA,EF  
!mH2IjcL  
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//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) z8FeL5.(  
{ O0Y/y2d  
for(int i=1;;i++) #FKo:id`K  
{
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String header=con.getHeaderFieldKey(i); ?khwupdi  
if(header!=null) A$.woE@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [xq"[*Evv  
Utility.log(header+" : "+con.getHeaderField(header)); &(3kwdI  
else }6b=2Z}  
break; 1wSJw  
} U,S&"`a  
} :{?8rA5  
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public void splitterStop() CJ0j2e/  
{ ';4DUhp  
bStop = true; n_vopDMm  
} VXlTA>a }  
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} A$vCm  
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/* }8J77[>/  
**FileAccess.java T ) T0.c  
*//文件访问(定位，写) ?-[.H^]s~  
package NetFox; 'eg?W_zu  
import java.io.*; &g;4;)p*8  
9^l_\:4  
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public class FileAccessI implements Serializable{ ,!U5;  
]^:l?F\h  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 uCuXY#R+  
RandomAccessFile oSavedFile; 8t3@Hi  
long nPos; pn?c6KvO  
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public FileAccessI() throws IOException v]+,kbT  
{ } _Yk.@J5  
this("",0); {tn%HK">  
} 8 St`,Tq)  
+Z[(s!  
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public FileAccessI(String sName,long nPos) throws IOException aY7kl  
{ P[-2^1P
"  
oSavedFile = new RandomAccessFile(sName,"rw"); 5\/h3i"I  
this.nPos = nPos; rSDS9Vf(  
oSavedFile.seek(nPos); B]oIFLED  
} gn"_()8cT  
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i)=!U>B_0  
public synchronized int write(byte[] b,int nStart,int nLen) >J>4g;Y  
{
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int n = -1; 6?OH"!b2-}  
try{ !Ziq^o.  
oSavedFile.write(b,nStart,nLen); 'V
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n = nLen; 2}:scag  
} pJ[7m  
catch(IOException e) (5Q,d [B  
{ |mvy@
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e.printStackTrace (); Q)x`'[3"7W  
} ma.yI};
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return n; [P`t8  
} 3l"7$B  
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} &z;F'>"  
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/* TIlBT{A<  
**SiteInfoBean.java b?`8-g  
*/ z1A[rbe=4w  
package NetFox; _uU}J5d.  
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* bx%hX  
public class SiteInfoBean { .lm^+1}r  
Mo`7YS-Y  
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private String sSiteURL; //Site's URL P_)h8-!+ $  
private String sFilePath; //Saved File's Path dE9xan  
private String sFileName; //Saved File's Name (.Yt| "j  
private int nSplitter; //Count of Splited Downloading File c%Ht; sK`*  
{X$8yy2zC5  
wlr/zquAE9  
public SiteInfoBean() ]0<T,m Z  
{//nSplitter的缺省值为5 H/m -$;cF3  
//default value of nSplitter is 5 CbTYt6DC  
this("","","",5); 6u^MfOc  
} rxtp?|v9  
M;*f(JY$  
{2?o:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qv|geBW  
{ 7N0V`&}T  
sSiteURL= sURL; 3uA%1 E  
sFilePath = sPath; .zf#S0y%(  
sFileName = sName; aV3:wp]Gn  
this.nSplitter = nSpiltter; `PK1zS
r  
a!YpSFr  
 mD`
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} *ZP
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public String getSSiteURL() I\J^@&
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{ _IiTB  
return sSiteURL; {p&M(
W]  
} d>@&[C!28  
!ckm
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public void setSSiteURL(String value) p<IMWe'tP  
{ Om`VQ?  
sSiteURL = value; S(xlN7=  
} +$
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public String getSFilePath() #M$Gj>E%4  
{ I_66q7U"0  
return sFilePath; ?u`+?"'H  
} M]PH1 2Ob  
"@IrBi6  
Ng=XH"ce~  
public void setSFilePath(String value) D9`J||]E  
{ #T_m|LN7  
sFilePath = value; B ^>}M  
} .: ~);9kj  

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public String getSFileName() 2u
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{ 9&e=s<6dO  
return sFileName; QTX5F5w  
} w~EBm=v_>  
1"k"<{%  
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public void setSFileName(String value) |E:q!4?0  
{ #;ezMRKM"  
sFileName = value; =@w,D.5h  
} 'lwLe3.c  
h">L>*Wfx  
hkOhY3K5  
public int getNSplitter() W8hf  Qpw  
{ y;W|)  
return nSplitter; Z9rmlVU6!  
} $*EK v'g[n  
d
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public void setNSplitter(int nCount) C" vj#Tx  
{ 3(D!]ku~
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nSplitter = nCount; KG:CVIW Y  
} rXR=fj= 2  
} NYopt?Xg  
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m,UMb#7Y  
/* !ER,o_T<  
**Utility.java (80 Tbi~+  
*/ 2xy &mNx  
package NetFox; *xY}?vSs  
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@ 63Uk2{W>  
public class Utility { aH6{_eY  
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9I3vW]0x[  
public Utility() ,S.<qmf  
{ ktQMkEj#  
o/Z  
&fH;A X.  
} tNsiokOm  
'F3cvpc`  
//线程睡眠 D vG9(Eh  
public static void sleep(int nSecond) C:Tjue{G2  
{ )*!"6d)^  
try{ P,.<3W"4i  
Thread.sleep(nSecond); ?[~"$  
} ?LE\pk R  
catch(Exception e) %6-5hBzZN  
{ b5r.N1ms  
e.printStackTrace (); %"#%/>U4  
} v X=zqV  
} 6:Eu[PE~w  
Aj|Gqw>  
//日志 e)
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public static void log(String sMsg) cBxBIC  
{ /]pBcb|<  
System.err.println(sMsg); .Pz( 0Y  
} x\/N09  
px`o.%`'  
f+*wDH  
public static void log(int sMsg) tl.I:A5L  
{ }6YD5?4  
System.err.println(sMsg); ci]IH]x  
} 6$42-a%b  
} ~nul[>z  
!VNLjbee.  
Vn:BasS%  
/* kGaK(^w  
**TestMethod.java cRt[{HE  
*/ )"Ef* /+  
package NetFox; cY&SKV#  
/{|<3CEe  
EvA{@g4>  
public class TestMethod { \SA"DT  
,{4G@:Fm  
3I|&}+Z6  
public TestMethod() O3U6"{yJ)  
{ ///xx/weblogic60b2_win.exe :z=C   
try{ ^Rgm3?7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "S#}iYp  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <>!Y[Xr^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8&q|*/2  
fileFetch.start(); 2|J>e(&akY  
} &hciv\YT2W  
catch(Exception e){e.printStackTrace ();} j2oHwt6"  
3Zy$NsY3  
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} HH_w!_f  
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public static void main(String[] args) -N'xQ(#n3q  
{ bf~gWzA  
new TestMethod(); m(~5X0  
} \W"N{N  
} ;QMRm<CLV  
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