http断点续传简单实现（java)

/* CY.
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**SiteFileFetch.java 1OV] W f  
*/ b1;h6AeL  
package NetFox; -/2B fIq  
import java.io.*; jib pZ)  
import java.net.*; #M4LG; B  
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public class SiteFileFetch extends Thread { UD.ZnE{"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *Ms&WYN-  
long[] nStartPos; //开始位置 I;n<) >  
long[] nEndPos; //结束位置 B&_Z&H=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 I0qJr2[X~  
long nFileLength; //文件长度 I1rB,%p
  
boolean bFirst = true; //是否第一次取文件 ;&'ryYrex  
boolean bStop = false; //停止标志 u-tD_U
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File tmpFile; //文件下载的临时信息 ^qi+Y)dU|  
DataOutputStream output; //输出到文件的输出流 9hssIZO  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )FPn_p#3]  
public SiteFileFetch(SiteInfoBean bean) throws IOException q
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{ #eX
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siteInfoBean = bean; G"tlJ7$myQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V.6pfL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8I Ip,#%v  
if(tmpFile.exists ()) OCq5}%yU&i  
{ Y]5spqG  
bFirst = false; hn\d{HP  
read_nPos(); h-RhmQA=Iz  
} Sk)lT^by  
else (&v,3>3]  
{ }!?RB v'W  
nStartPos = new long[bean.getNSplitter()]; Gs,e8ri!  
nEndPos = new long[bean.getNSplitter()]; ;)wk^W  
} e ;^}@X  
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} QPh3(K1w^  
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public void run() bwcr/J(Nb  
{ Fn iht<  
//获得文件长度 AJE$Z0{q  
//分割文件 w^("Pg`  
//实例FileSplitterFetch U=7nz|  
//启动FileSplitterFetch线程 dsj}GgG?Z  
//等待子线程返回 0TSB<,9a[  
try{ #ti%hm  
if(bFirst) BvH?d]%  
{ 8e^uKYR<  
nFileLength = getFileSize(); k<MQ  
if(nFileLength == -1) 7S^G]g!x  
{ ^\kH^  
System.err.println("File Length is not known!"); SH#*Lc   
} -(>Ch>O  
else if(nFileLength == -2) ,,+4d :8$  
{ 8ICV"8(  
System.err.println("File is not access!"); 6GPI gPL,  
} wW/q#kc  
else X/90S2=P  
{ ^sFO[cYo  
for(int i=0;i<nStartPos.length;i++) pPag@L  
{ gu%i|-}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); k3nvML,bv  
} .Gvk5Wn  
for(int i=0;i<nEndPos.length-1;i++) 'TuaP`]<  
{ !c{F{t-a  
nEndPos = nStartPos[i+1]; $IjI{%  
} Xx%<rsA>F  
nEndPos[nEndPos.length-1] = nFileLength; )J0h\ky  
} Cl!(F6K*  
} DW78SoyedZ  
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//启动子线程 3-,W? "aC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Dg"szJ-   
for(int i=0;i<nStartPos.length;i++) K)se$vb6  
{ FpU8$o~r{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y22DBB8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W3d+t?28  
nStartPos,nEndPos,i); %''L7o.#a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 
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fileSplitterFetch.start(); ?@;)2B|q  
} s,8zj<dUv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,W|-?b?   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 02trjp.f  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B>m*!n:l  
nEndPos = " + nFileLength); '21gUYm  
// fileSplitterFetch[nPos.length-1].start(); )wCNLi>4
 
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//等待子线程结束 Hh*?[-&r~  
//int count = 0; xE]y*\  
//是否结束while循环 ^3S&LC 1;|  
boolean breakWhile = false; V$w lOMp  
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while(!bStop) ed}#S~4q  
{ 3l41"5Fy&  
write_nPos(); GGr82)E  
Utility.sleep(500); Qubu;[0+a  
breakWhile = true; 6]d]0TW_  
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for(int i=0;i<nStartPos.length;i++) qt*+ D  
{ 0V21_".S  
if(!fileSplitterFetch.bDownOver) X?wZ7*'1  
{ x: _[R{B  
breakWhile = false; |*UB/8C^/!  
break; B(94;,(  
} z F.@rXl  
} 
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if(breakWhile) MuQ)F-GSUu  
break; _8 |X820  
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//count++; *|Er;Thw  
//if(count>4) .#$2,"8  
// siteStop(); }aR}ZzK/v  
}  0.0-rd>  
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)%MC*Z:^  
System.err.println("文件下载结束！"); i2c|_B  
} O0xqA\  
catch(Exception e){e.printStackTrace ();} y32$b,%Xi,  
} KNd<8{'.  
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/*,_\ ;  
//获得文件长度 ktx| c19  
public long getFileSize() D_0Vu/v  
{ j]<K%lwp  
int nFileLength = -1; =3w;<1 ?'  
try{ 9 %4:eTcp  
URL url = new URL(siteInfoBean.getSSiteURL()); ;tZQ9#S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^PezV5(  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4fC:8\A  
@r/~Y]0Ye5  
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int responseCode=httpConnection.getResponseCode(); $=N?[h&4  
if(responseCode>=400) /B~[,ES@1  
{ J:glJ'4E  
processErrorCode(responseCode); ,r;xH}tbi  
return -2; //-2 represent access is error 6{HCF-cQd  
} u"*DI=pwb  
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String sHeader; & rab,I"  
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for(int i=1;;i++) z_fjmqa?  
{ y7fy9jQ 8.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SnmUh~`L~  
//Utility.log(in.readLine()); a~$Y;C_#<  
sHeader=httpConnection.getHeaderFieldKey(i); bC1G5`v_D  
if(sHeader!=null) !LwHKCj  
{ ~Q]5g7k=&  
if(sHeader.equals("Content-Length")) ~<n.5q%Z  
{ )B0%"0?`8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0O>ClE~P  
break; ~;#}aQYo  
} Q'jw=w!|g  
} ikV;]ox  
else ={zTQ+7S`  
break; 3EICdC  
} ^.!jD+=I  
} G#GZt\)F  
catch(IOException e){e.printStackTrace ();} %NxQb'  
catch(Exception e){e.printStackTrace ();} SI+Uq(k  
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Utility.log(nFileLength); Nb`qM]&  
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return nFileLength; /GC&@y0yi  
} 8$ u"92  
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//保存下载信息（文件指针位置） R/ZScOW[  
private void write_nPos() Pp tuXq%U  
{ Jq'8"  
try{ 6
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ~E7IU<B  
output.writeInt(nStartPos.length); =,#--1R7g  
for(int i=0;i<nStartPos.length;i++) d/&> `[i  
{ UgC65O2  
// output.writeLong(nPos); \}?X5X>  
output.writeLong(fileSplitterFetch.nStartPos); w&aZ 97{  
output.writeLong(fileSplitterFetch.nEndPos); 8'8`xu$  
} b
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output.close(); ]2wx
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} #Or;"}P>fB  
catch(IOException e){e.printStackTrace ();} ujX;wGje  
catch(Exception e){e.printStackTrace ();} V^5d5
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} Km8aHc]O~  
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//读取保存的下载信息（文件指针位置）  Qw}1q!89  
private void read_nPos() TB!I  
{
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try{ 7t:RQ`$:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ww2@!ng  
int nCount = input.readInt(); _xp8*2~-  
nStartPos = new long[nCount]; *
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nEndPos = new long[nCount]; 0B]q /G(  
for(int i=0;i<nStartPos.length;i++) rTIu'  
{ 6(f'P_*  
nStartPos = input.readLong(); Yg^ &4ZF  
nEndPos = input.readLong(); LZRg%3.E
 
} xf]K  
input.close(); c0gVW~I1  
} ;mG*Rad  
catch(IOException e){e.printStackTrace ();} :-46
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catch(Exception e){e.printStackTrace ();} 67II9\/  
} #_wq#rF  
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private void processErrorCode(int nErrorCode) 9qB0F_xl  
{ LKu\Mh|  
System.err.println("Error Code : " + nErrorCode); S%i^`_=Q  
} [8i)/5D4  
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//停止文件下载 USz~l7Xs  
public void siteStop() rGyAzL]  
{ fORkH^Y(&  
bStop = true; {_O!mI*  
for(int i=0;i<nStartPos.length;i++) o eUi  
fileSplitterFetch.splitterStop(); go uU  
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} ?BnU0R_r]  
} (j&:  
//负责部分文件的抓取 -Z"4W  
**FileSplitterFetch.java N]A# ecm  
*/ "La;$7ds  
package NetFox; r!mRUw'u  
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import java.io.*; x;n3 Zr;(  
import java.net.*; F)LbH&Kn  
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public class FileSplitterFetch extends Thread { YX0ysE*V:&  
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String sURL; //File URL i+*!"/De  
long nStartPos; //File Snippet Start Position +3)r szb72  
long nEndPos; //File Snippet End Position
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int nThreadID; //Thread's ID ~zqb{o^pT  
boolean bDownOver = false; //Downing is over ?l0eU@rwQ  
boolean bStop = false; //Stop identical E7:xPNU  
FileAccessI fileAccessI = null; //File Access interface =:-fK-d  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *;o%*:  
{ 6p9fq3~7Y  
this.sURL = sURL; HEF e?
 
this.nStartPos = nStart; *;Jb=  
this.nEndPos = nEnd; /T w{JO#Q  
nThreadID = id; ANM#Kx+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ax;[Em?
I  
} 2%W;#oi?  
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public void run() UlYFloZ  
{ 4Z"}W!A  
while(nStartPos < nEndPos && !bStop) m@td[^O-  
{ EhcJE;S)  
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try{ ] G&*HMtp  
URL url = new URL(sURL); b(iF0U>&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )kpEcMlR  
httpConnection.setRequestProperty("User-Agent","NetFox"); N~v6K}`}  
String sProperty = "bytes="+nStartPos+"-"; u^" I3u8$  
httpConnection.setRequestProperty("RANGE",sProperty); \Z[
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Utility.log(sProperty); )6OD@<r{  
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InputStream input = httpConnection.getInputStream(); -*C WF|<G  
//logResponseHead(httpConnection); IOy0WHl|  
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byte[] b = new byte[1024]; v@_1V  
int nRead; uoS:-v}/Y~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G{U#9   
{ IiU>VLa  
nStartPos += fileAccessI.write(b,0,nRead); i\i%WiRl  
//if(nThreadID == 1) $|N6I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T ozx0??)  
} z*\_+u~u  
7oE0;'  
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Utility.log("Thread " + nThreadID + " is over!"); 9`tK9  
bDownOver = true;  G 3Z"U  
//nPos = fileAccessI.write (b,0,nRead); D)d]o&  
} sg2;"E@  
catch(Exception e){e.printStackTrace ();} @!sK@&ow@%  
} AI|vL4*Xd  
} @(t3<g  
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//打印回应的头信息 *_(X$qfoW  
public void logResponseHead(HttpURLConnection con) Nu5|tf9%A  
{ %5o2I_Cjz  
for(int i=1;;i++) )l3Uf&v^f  
{ I652Fcj  
String header=con.getHeaderFieldKey(i); F-_u/C]  
if(header!=null) d>QFmsh-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); HBlk~eZ  
Utility.log(header+" : "+con.getHeaderField(header)); 50,'z?-_  
else !nvwRQ  
break; FY1iY/\Cn  
} E }L Hp  
} `|dyT6V0I_  
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public void splitterStop() {)[o*+9  
{ r/YJ,2!  
bStop = true; }A)\bffH  
} A;oHji#*  
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} |Y9>kXMl  
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/* FuhmLm'p  
**FileAccess.java YF%gs{  
*//文件访问(定位，写) ++cS^ Lo  
package NetFox; HW@wia  
import java.io.*; eg0_ <  
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public class FileAccessI implements Serializable{ Z)?$ZI@  

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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 -F5BJk  
RandomAccessFile oSavedFile; honh'j  
long nPos; X1j8tg  
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public FileAccessI() throws IOException $7x2TiAL  
{ s8h*nZ)v  
this("",0); <b 5DX  
} Aoe\\'O|V  
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public FileAccessI(String sName,long nPos) throws IOException tsXKhS;/w  
{ + G@N  
oSavedFile = new RandomAccessFile(sName,"rw"); $:9t(X)H  
this.nPos = nPos; c*bvZC^6  
oSavedFile.seek(nPos); je] DR~  
} {bj!]j
 
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6
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public synchronized int write(byte[] b,int nStart,int nLen)  X\^nV  
{ i]8O?Ab>?  
int n = -1; zakhJ  
try{ 2W AeSUX  
oSavedFile.write(b,nStart,nLen); .-gJS-.c  
n = nLen; D,#UJPyg  
} H$![]Ujq  
catch(IOException e) ,i>`Urd  
{ Bf{u:TCK  
e.printStackTrace (); 7;>|9k  
} q lc@$  
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return n; 9"~ FKMN  
}
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} 4cjfn'x  
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/* dCC*|b8h  
**SiteInfoBean.java hU?DLl:bXF  
*/ MAh1tYs4D
 
package NetFox;
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public class SiteInfoBean { +%dXB&9x|Z  
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private String sSiteURL; //Site's URL <jh4P!\&j  
private String sFilePath; //Saved File's Path MN?aPpr>  
private String sFileName; //Saved File's Name "@Vyc6L  
private int nSplitter; //Count of Splited Downloading File *22Vc2[i;  
qO6M5g:   
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public SiteInfoBean() )Sn0Y B  
{//nSplitter的缺省值为5 $xO8?  
//default value of nSplitter is 5 m:@y_:X0  
this("","","",5); U1\7Hcs$  
} 4 m:h&^`N  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) h"FI]jK|}  
{ $1f2'_`8~  
sSiteURL= sURL; BgQEd@cN  
sFilePath = sPath; k:0j;\Sx  
sFileName = sName; zWY988fX0  
this.nSplitter = nSpiltter; 0Lo8pe`DH  
>kXscbRL7  
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} L(y70T  
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public String getSSiteURL() u\\t~<8  
{ Hw \of  
return sSiteURL; $/wm k7T  
} e]4$H.dP  
c'oiW)8;A  
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public void setSSiteURL(String value) UtQj<18<  
{ )/RG-L  
sSiteURL = value; 4'QX1
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} uw;Sfx,s  
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public String getSFilePath() CsZ~LQ=DB  
{ s6H.Q$3L  
return sFilePath; a?[[F{X9^  
} Iz0$T.T  
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public void setSFilePath(String value) ibkB>n{(  
{ U,g8:M xHK  
sFilePath = value; H4g8 1V=  
} ~[;r) g\  
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public String getSFileName() ddQ+EY@!  
{ wJC[[_"3 I  
return sFileName; D$l!lRu8+L  
} lV\iYX2#  
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public void setSFileName(String value) J"aw 1  
{ ZHTi4JY  
sFileName = value; 1T!o
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} A \/~u"Y  
A@V$~&JCL5  
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public int getNSplitter() #9,8{ O"  
{ g+#<;Gbpe  
return nSplitter; h>pu^ `hk  
} :-?ZU4)  
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public void setNSplitter(int nCount) +ktv:d  
{ #W~jQ5NS\  
nSplitter = nCount; DQ.
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} A5nggg4  
} u W]gBhO$O  
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/* QAkK5,`vV.  
**Utility.java |=0vgwd"S  
*/ 78l);/E{v  
package NetFox; yCQvo(V[F  
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public class Utility { o GuAF q  
$;^|]/-  
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public Utility() s#^0[ Rt  
{ tVG;A&\,6  
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} [* <x)  
S~/2Bw!2  
//线程睡眠 :E9pdx+  
public static void sleep(int nSecond) /EjXyrn2  
{ )Rn\6ka  
try{ gX"-3w  
Thread.sleep(nSecond); \c2x udU  
} cZVx4y%kz
 
catch(Exception e) O#D{:H_dD>  
{ aM~IRLmK  
e.printStackTrace (); cKTjQJ#  
} Ta\F~$M  
} u8c@q'_  
}ny7LQ  
//日志 #B\s'j[A"  
public static void log(String sMsg) 2"D4q(@  
{ k A3K  
System.err.println(sMsg); toGiG|L  
} w[X-Q+7p(t  
}u;K<<h:  
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public static void log(int sMsg) F!z ^0+H(  
{ 2E1`r@L  
System.err.println(sMsg); f2e;N[D  
} D$>!vD'  
} t=B1yvE"  
I8XP`Ccq  
^6 wWv&G[8  
/* sU>IETo  
**TestMethod.java P*KIk~J  
*/ t+v%%N_  
package NetFox; NgTB4I8P  
@ki|#ro  
rt^~ I\V  
public class TestMethod { N**)8(  
`df!-\#  
3CD#OCz7&  
public TestMethod() ),yar9C  
{ ///xx/weblogic60b2_win.exe dFBFXy  
try{ sFM$O232  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &|x7T<,)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >ZJ]yhbhK  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8&U Mmbgy  
fileFetch.start(); 0si1:+t-[+  
} :\[l~S  
catch(Exception e){e.printStackTrace ();} X,
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} pg%(6dqK4  
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public static void main(String[] args) r#OPW7mhE  
{ .e7tq\k  
new TestMethod(); i.^ytbH  
} Rq|6d M6H  
} loIb}8  
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