http断点续传简单实现（java)

/* x']'ODs  
**SiteFileFetch.java ?'P}ZC8P  
*/ <r:AJ;  
package NetFox; J;obh.}u"{  
import java.io.*; dW4jkjap  
import java.net.*; wUCxa>h'  
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}?9&xVh?\  
public class SiteFileFetch extends Thread { +v;z^+  
;WSW&2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =p'+kS+  
long[] nStartPos; //开始位置 JnsJ]_<  
long[] nEndPos; //结束位置 r+Ki`HD%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6"Fn$ :l?  
long nFileLength; //文件长度 t>cGfA  
boolean bFirst = true; //是否第一次取文件 :Mu*E5  
boolean bStop = false; //停止标志 swF{}S"  
File tmpFile; //文件下载的临时信息 t6nRg  
DataOutputStream output; //输出到文件的输出流 P'U2hCif  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Io.RT+slB  
public SiteFileFetch(SiteInfoBean bean) throws IOException }aR
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{ ^MvuFA,C  
siteInfoBean = bean; AVpg  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \Vf:/9^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g&FTX
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if(tmpFile.exists ()) g.Xk6"kO  
{ %)r ~GCd  
bFirst = false; r+FEgSDa]  
read_nPos(); Gc|)4c  
} mtv8Bm=<  
else @[3c1B6K  
{ S\TXx79PhC  
nStartPos = new long[bean.getNSplitter()]; U0_^6zd_
 
nEndPos = new long[bean.getNSplitter()]; =D/zC'l  
} T-%=t
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} Q6Gw!!Z5EA  
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public void run() E
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{ f4f2xe7\Q  
//获得文件长度 |ri)-Bk ,  
//分割文件 X 0y$xC|<  
//实例FileSplitterFetch F^O83[S  
//启动FileSplitterFetch线程 jfuHZ^YA  
//等待子线程返回 8?+|4:#=*J  
try{ GD
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if(bFirst) IO+]^nY`  
{ $,4h\>1WP  
nFileLength = getFileSize(); P"w\hF  
if(nFileLength == -1) L|'^P3#7`  
{ )dT@0Ys%  
System.err.println("File Length is not known!"); CFaY=Cy  
} 3$\k=q3`#  
else if(nFileLength == -2) KrE'M  
{ USBQEt  
System.err.println("File is not access!"); t7+A!7b{  
} .9jKD*U|  
else A'|!O:s   
{ 5f-b>=02  
for(int i=0;i<nStartPos.length;i++) >d/H4;8  
{ L)sgW(@2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); HxG8'G  
} k +-w%  
for(int i=0;i<nEndPos.length-1;i++) {a7~P0$  
{ bNea5u##  
nEndPos = nStartPos[i+1]; >@YefN
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} _wq?Pa<)e  
nEndPos[nEndPos.length-1] = nFileLength; JWn26,  
} AcH-TIgM/  
} 7zM:z,  
}s}g}t8v-  
$T'!??|IF  
//启动子线程 >fPo_@O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; qkb'@f=  
for(int i=0;i<nStartPos.length;i++) g68p9#G  
{ 2B,O
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^#/FkEt7bp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), AJPvwu}D  
nStartPos,nEndPos,i); 
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )kD
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fileSplitterFetch.start(); ^jdU4  
} ;5[KZ8j6Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @YJI'Hf67  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !|cg=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", oo5=5s6 3}  
nEndPos = " + nFileLength); Fhoyji4  
// fileSplitterFetch[nPos.length-1].start(); zKJ2~=  
=&HLz 7|  
tdy2ZPVtTV  
//等待子线程结束 jwZ,_CK  
//int count = 0; *ukyQZ9  
//是否结束while循环 r~4uIUE{  
boolean breakWhile = false; 0'QWa{dS\  
\CbJU  
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while(!bStop) }lJ;|kx$  
{ WyL+HB}  
write_nPos(); )9QtnM  
Utility.sleep(500); {z#2gc'Q  
breakWhile = true; WjV15\,  
!rvEo =^  
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5  
for(int i=0;i<nStartPos.length;i++) x(_[D08/TT  
{ 0#q=-M/?`  
if(!fileSplitterFetch.bDownOver) N##`  
{ bDI%}k9#  
breakWhile = false; 6cQgp]%  
break; okNo-\Dh!  
} G0cG%sIl  
} ;JW_4;-  
if(breakWhile) .])prp8  
break; NFK
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//count++; 6b|?@  
//if(count>4) 8)i""OD@I  
// siteStop(); g?C;b>4  
} bF)G+IH  
s27IeF3  
hsZ/Vnn`  
System.err.println("文件下载结束！"); H}@:Br
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} gEASYIQ  
catch(Exception e){e.printStackTrace ();} =bVPHrKNQ  
}  >@ t  
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7  
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//获得文件长度 bS.w<V Ew  
public long getFileSize() DSGcxM+  
{ YIU3}sJ!  
int nFileLength = -1; d_RgKdR )k  
try{ >tD=t8  
URL url = new URL(siteInfoBean.getSSiteURL()); aQk&#OQy  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |@q
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httpConnection.setRequestProperty("User-Agent","NetFox"); 3r\8v`^>  
[,%=\%5
 
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int responseCode=httpConnection.getResponseCode(); 8
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if(responseCode>=400) i;[y!U  
{ 0}{xH  
processErrorCode(responseCode); p7h#.m~
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return -2; //-2 represent access is error lOIk$"Ne  
} I7f ^2  
D$>_W,*V  
H'+7z-%G  
String sHeader; {4"V)9o-1>  
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for(int i=1;;i++) u8e_Lqx?  
{ jm_-f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )P$(]{  
//Utility.log(in.readLine()); 3} A$+PX  
sHeader=httpConnection.getHeaderFieldKey(i); / )0hsQs  
if(sHeader!=null) w =^.ICyb@  
{ UZZJtQt  
if(sHeader.equals("Content-Length")) <hT\xBb:  
{ ^;C&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); g7oY
1;  
break; %H{p&ms  
} |HazM9=  
} 1uF$$E6[  
else >1y6DC  
break;  EM,C  
} ]@q%d
sz  
} en<mm#Ab  
catch(IOException e){e.printStackTrace ();} Lu.zc='\  
catch(Exception e){e.printStackTrace ();} UHBXq;?&q  
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Utility.log(nFileLength); GW2\YU^{  
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return nFileLength; UD I{4+z  
} }r}*=;Ea  
8^mE<  
|rmelQ-  
//保存下载信息（文件指针位置） 4=PjS<Lu8  
private void write_nPos() jU,Xlgz(A  
{ 3f;=#|l  
try{ <,d550GSm  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 37AVk
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output.writeInt(nStartPos.length); 5>532X(0  
for(int i=0;i<nStartPos.length;i++) j;x()iZ<  
{ ez4!5&TzRm  
// output.writeLong(nPos); L"_XWno  
output.writeLong(fileSplitterFetch.nStartPos); J0G@]H  
output.writeLong(fileSplitterFetch.nEndPos); ">uN={Iy  
} Aoa8Q E  
output.close(); H`EhsYYK  
} gY}In+S  
catch(IOException e){e.printStackTrace ();} Hxu5Dx5![  
catch(Exception e){e.printStackTrace ();} >A#5` $i  
} _0/unJl`  
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//读取保存的下载信息（文件指针位置） Z
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private void read_nPos() Hq@+m!  
{ !oLn=  
try{ sJHVnMA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4WT
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int nCount = input.readInt();  ZR.k'  
nStartPos = new long[nCount]; !\4x{W
a]  
nEndPos = new long[nCount]; "hkcN+=  
for(int i=0;i<nStartPos.length;i++) g` rr3jP  
{ =]5tYI
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nStartPos = input.readLong(); T:}Q3  
nEndPos = input.readLong(); ~o}:!y  
} PK\ZRl  
input.close(); \ovs[&  
} f}otIf  
catch(IOException e){e.printStackTrace ();} a[{$4JpK  
catch(Exception e){e.printStackTrace ();} 3i^X9[.  
} F%>$WN#2  
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private void processErrorCode(int nErrorCode) )ycI.[C  
{ ;?h[WIy  
System.err.println("Error Code : " + nErrorCode); LG}{ibB  
} kR]P/4r  
*_V+K  
rYUIFPN  
//停止文件下载 $H:!3-/  
public void siteStop() Szo'[/ [R  
{ 2a d|v]  
bStop = true; ">V&{a-C4  
for(int i=0;i<nStartPos.length;i++) (*-wiL  
fileSplitterFetch.splitterStop(); /V
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+{UY9_~\3  
} "ubp`7%67  
} #~0Nk6*u  
//负责部分文件的抓取 J}|X  
**FileSplitterFetch.java /$^Tou/v  
*/ :X>Wd+lY:_  
package NetFox; Q_mphW:[  
-jH|L{Iyq}  
dPUe5k)G_  
import java.io.*; 1M ?BSH{  
import java.net.*;
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 Y@,iDQ  
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public class FileSplitterFetch extends Thread { $4bc!  
7FX4|]  
>?g@Nt8  
String sURL; //File URL 1?@HOu  
long nStartPos; //File Snippet Start Position /9vi  
long nEndPos; //File Snippet End Position AXyXK??  
int nThreadID; //Thread's ID B,b8\\^k|  
boolean bDownOver = false; //Downing is over "Eh=@?]S_  
boolean bStop = false; //Stop identical ax@H^Gj@2  
FileAccessI fileAccessI = null; //File Access interface mhbczVw  
>oh
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41 F;X{Br  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N8A)lYT]_u  
{ )JMqC+J3*t  
this.sURL = sURL; k4+vI1Cs  
this.nStartPos = nStart; ~IhAO}1  
this.nEndPos = nEnd; 9a`LrB  
nThreadID = id; RhWQ:l]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 YRZ\nun  
} GDu^P+^  
}[
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qqDg2,Yb  
public void run() Z\ hcK:  
{ )O'LE&kQ|  
while(nStartPos < nEndPos && !bStop) {f06Ki  
{ Gxr\a2Z&r%  
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;m7V]h? R  
try{ >$q   
URL url = new URL(sURL); :a wt7lqv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
4v[y^P  
httpConnection.setRequestProperty("User-Agent","NetFox"); _i_='dsyW/  
String sProperty = "bytes="+nStartPos+"-"; s'HsLe0|  
httpConnection.setRequestProperty("RANGE",sProperty); @9/I^Zk  
Utility.log(sProperty); PV68d; $:8  
.}faWzRH9  
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InputStream input = httpConnection.getInputStream(); ybaY+![*  
//logResponseHead(httpConnection); G`!x+
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=\Q<TY  
byte[] b = new byte[1024]; *-0s `rC  
int nRead; }`R,C~-|^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R"ON5,E  
{ #XQ/y}(  
nStartPos += fileAccessI.write(b,0,nRead); w8lrpbLh  
//if(nThreadID == 1) U]hqRL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Yp\n
=#$[  
} bBIh}aDN  
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Utility.log("Thread " + nThreadID + " is over!"); "FHJ_$!  
bDownOver = true; M9)4ihK  
//nPos = fileAccessI.write (b,0,nRead); i6Z7
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} a (U52dO,  
catch(Exception e){e.printStackTrace ();} HZ3;2k  
} S:1[CNL;  
} CPB{eQeDuv  
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PUQ",;&y1  
//打印回应的头信息 FjCGD4x1N  
public void logResponseHead(HttpURLConnection con) rLTBBvV  
{ ^4=#,K  
for(int i=1;;i++) rKgl:sj+  
{ [O3:?BNY  
String header=con.getHeaderFieldKey(i); 9NTNulD>P  
if(header!=null) a1pp=3Pd?~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @i ~A7L0/  
Utility.log(header+" : "+con.getHeaderField(header)); +4yre^gC  
else `v-[&  
break; ~'M<S=W  
} =lAjQt
 
} E{ /, b)  
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/&Q{B f  
public void splitterStop() /r4l7K  
{ |d0ZB_ci  
bStop = true; xPZ>vCg  
} |_?e.}K  
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} jG>W+lq  
O9daeIF0#  
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/* _}R9!R0O  
**FileAccess.java :#:|:q.]  
*//文件访问(定位，写) 0AHQ(+Ap  
package NetFox; 5W)ST&YPL*  
import java.io.*; *2Pr1U  
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"$(+M t^  
public class FileAccessI implements Serializable{ tWn dAM(U7  
5x+]uABE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ` <1Wf  
RandomAccessFile oSavedFile; z}E_wg  
long nPos; X['9;1Xr  
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\Th<7WbR6#  
public FileAccessI() throws IOException #Hrzk!&9  
{ m*m),mZ"  
this("",0); JP8}+  
} * zp tbZ  
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0O"W0s"T#  
public FileAccessI(String sName,long nPos) throws IOException b`X''6  
{ 6+$2rS$1V  
oSavedFile = new RandomAccessFile(sName,"rw"); g-qXS]y7  
this.nPos = nPos; G(t:s5:  
oSavedFile.seek(nPos); ujV{AF`JfB  
} <UGaIb  
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public synchronized int write(byte[] b,int nStart,int nLen) Fbo"Csn_  
{ Tu(:?  
int n = -1; !EIH"`>!  
try{ <~mqb=qA$  
oSavedFile.write(b,nStart,nLen); \ZRII<k5)  
n = nLen; bbjba36RO  
} _-fLD  
catch(IOException e) 6Y2,fW8i,  
{ wwl,F=| Y  
e.printStackTrace (); ZJ{DW4#t  
} 3@=<4$  
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7Q/H+)  
return n; .45wwouZkc  
} gp9O%g3'  
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} W\[E  
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/* ~"S5KroN  
**SiteInfoBean.java sA6HkB.  
*/ |6NvByc,  
package NetFox; :G#%+,  
xLIyh7$t  
@16y%]Q-E#  
public class SiteInfoBean { Oi?Q^ISxP  
,;6%s>Cvd(  
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private String sSiteURL; //Site's URL TJP;!uX  
private String sFilePath; //Saved File's Path o,k#ft<  
private String sFileName; //Saved File's Name M(8xwo-W  
private int nSplitter; //Count of Splited Downloading File 4oF,;o+v\4  
TPb&";4ROf  
*Iw19o-I  
public SiteInfoBean() _`Kh8G {e  
{//nSplitter的缺省值为5 E2 'Al6^C  
//default value of nSplitter is 5 0D:uM$ i]  
this("","","",5); ' Sd&I:
?  
} I-.?qcy~  
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:xq^T  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y3*IF2G  
{ b<fN,U<k  
sSiteURL= sURL; .f!'>_  
sFilePath = sPath; 21$^k
5  
sFileName = sName; JKmd'ZGw  
this.nSplitter = nSpiltter; dd=5`Bo9Yh  
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s5 Fn("h]n  
} d{!zJ+n  
#oGvxc7  
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public String getSSiteURL() ^<yM0'0t  
{ ~$a%& ]\  
return sSiteURL; +&AU&2As  
} kGq<Zmy|  
n;b9f|&z  
a(o[ bH.|;  
public void setSSiteURL(String value) 
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{ %4To@#c  
sSiteURL = value; u*;53 43  
} {iq{<;)U?U  
/`x|-9  
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public String getSFilePath() DA4!-\bt@  
{ K3UG6S\B  
return sFilePath; \v_t: "  
} A%M&{S'+|X  
"ZVBn!  
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public void setSFilePath(String value) q14A'XW  
{ [laX~(ND{  
sFilePath = value; "=!
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} Ah2XwFg?  
1[`l`Truz  
*DoEDw  
public String getSFileName() d0Kg,HB  
{ S+OI?QS  
return sFileName; U7fE6&g  
} f{z%PI[  
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uJp}9B60_  
public void setSFileName(String value) vrW9<{  
{ 7erao-  
sFileName = value; s9:2aLZ{  
} VZlvmN  
!%M-w0vC9  
|QgXSe7  
public int getNSplitter() 0_y%Qj^e  
{ 01q7n`o#zf  
return nSplitter; |]\bgh  
} {}^ELw  
6k3l/~R  
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public void setNSplitter(int nCount) ujWHO$uz!  
{ ng<`2XgU  
nSplitter = nCount; d<b,LD^  
} kWz%v  
} `Zi#rr|)L  
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_0j}(Q>|H#  
/* +@qk=]3a  
**Utility.java
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*/ yEqmB4^-  
package NetFox; uN(~JPAw5  
-5 W0K}  
@>:07]Dxo  
public class Utility { C[&&.w8Pm  
lM1!2d'P  
:d2u?+F  
public Utility() B:r-')!0$#  
{ W=\dsdnu*  
C;) xjZiR  
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} 3ElpS^2W  
# |I@`#O  
//线程睡眠 Yr=mLT|JN  
public static void sleep(int nSecond) l9ihW^  
{ mfN@tMp  
try{ >C}RZdO~  
Thread.sleep(nSecond); FVmg&[ .  
} *&0Hz{|  
catch(Exception e)
~&/Gx_KU  
{ #"{8Z&Z  
e.printStackTrace (); wf@2&vJ  
} ;2|H6IN"  
} LI<5;oE;  
] zY  
//日志 ui{_w @o  
public static void log(String sMsg)  :Y
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{ VT7NWTJ,  
System.err.println(sMsg); T!a[@,)_  
} U}0/V c
26  
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k-e@G'  
public static void log(int sMsg) KxwLKaImI  
{ %nh'F6bNgv  
System.err.println(sMsg); U
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} lpUtNy  
} 8!SiTOzR?  
OJ 5 !+#>  
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/* ACYn87tq  
**TestMethod.java TMCA?r%Y\  
*/ AZy2Pu56  
package NetFox; ?&m]du#6  
$SVGpEw  
#Vigu,zY  
public class TestMethod { Rk[ * p  
>pvg0Fh  
*KH@u  
public TestMethod() +:%FJCOT  
{ ///xx/weblogic60b2_win.exe a4RFn\4?  
try{ DZ.trtK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 34Khg  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); a?~csP^?}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); A_~
5|  
fileFetch.start(); -$t,}3  
}
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catch(Exception e){e.printStackTrace ();} !cwVJe  
:[f`HY
&  
"@w%TcA  
} qjzW9yV+  
zxUj1  
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public static void main(String[] args) uE`|0  
{ yKEFne8^  
new TestMethod(); oK:P@V6!  
} L_K\i?  
} WcO,4:  
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