http断点续传简单实现（java)

/* >_c5r?]SG  
**SiteFileFetch.java i
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*/ *\wp?s>-t  
package NetFox; `}m
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import java.io.*; SG?Nsp^%`B  
import java.net.*; 9%iUG(DC  
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277ASCWLkU  
public class SiteFileFetch extends Thread { >6~k9>nDb<  
9U {y1}  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 9prU+9  
long[] nStartPos; //开始位置 Ja]?&j  
long[] nEndPos; //结束位置 osOVg0Gyj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 l"{Sm6:;-  
long nFileLength; //文件长度 G/d4f?RU  
boolean bFirst = true; //是否第一次取文件 ( 7ws{)  
boolean bStop = false; //停止标志 Zes+/.sA}]  
File tmpFile; //文件下载的临时信息 v}sY|p"  
DataOutputStream output; //输出到文件的输出流 jYVE8Y)my  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2[B4f7  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]&ixhW  
{ @)>D)
)+  
siteInfoBean = bean; f`8OM}un&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4"@GNk~e  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); YC=S5;  
if(tmpFile.exists ()) ~1*A  
{ Y7GF$}%UL  
bFirst = false; M wab!Ya  
read_nPos(); \dlph  
} .c^ ggy%  
else =39 ?:VoD  
{ DY{cQb  
nStartPos = new long[bean.getNSplitter()]; RGIoI]_  
nEndPos = new long[bean.getNSplitter()]; R0;efD  
} _Cy:]2o  
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} [pg}S#A  
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public void run() T#!lPH :&h  
{ #.5
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//获得文件长度
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//分割文件 NQ|xM"MqD  
//实例FileSplitterFetch 3Z>YV]YbeU  
//启动FileSplitterFetch线程 zTo8OPr  
//等待子线程返回 Aaw(Ed  
try{ 1%J.WH6eQ  
if(bFirst) )9=(|Lp  
{ Qn:kz*:  
nFileLength = getFileSize(); a :HNg  
if(nFileLength == -1) gVU1Y6.  
{ V%CUMH =U  
System.err.println("File Length is not known!"); *zVvQ=  
} [U\
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else if(nFileLength == -2) LS.r%:$mb  
{ C+K=[

 
System.err.println("File is not access!"); XD-^w_  
} Uh|>Skic4  
else WxGSv#u  
{ RbQ <m!A  
for(int i=0;i<nStartPos.length;i++) ~ eN8|SR  
{ \&}G]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7\/5r.  
} (A/0@f1#  
for(int i=0;i<nEndPos.length-1;i++) beZ(o?uK  
{ }Ia 0"J4  
nEndPos = nStartPos[i+1]; BH@b1}  
} > %*B`oqo  
nEndPos[nEndPos.length-1] = nFileLength; 6ri#Lw  
} x:5dCI  
} (:\LWJX0=  
u/AT-er;  
yu&Kh4AP  
//启动子线程 ]UNZd/hIL  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; o;`
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for(int i=0;i<nStartPos.length;i++) `Y3(~~YGn  
{ /N^~U&7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ff"gadRXd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),
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nStartPos,nEndPos,i); rhY_|bi4P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *,#q'!Hq  
fileSplitterFetch.start(); cfoYnM  
} 3;$bS<>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V2kWiyN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6 ,N6jaW  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  pbB2wt  
nEndPos = " + nFileLength); _|n=cC4Qu  
// fileSplitterFetch[nPos.length-1].start(); K&pM o.  
q#1X[A()  
(:$9%,x  
//等待子线程结束 ZTf_#eS$  
//int count = 0; Uh6mGLz*&  
//是否结束while循环 c
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boolean breakWhile = false; T_L6 t66I  
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while(!bStop) Hc!!tbBQ  
{ b!~TAT&8  
write_nPos(); :|XCnK0
 
Utility.sleep(500); e`DsP8-&v  
breakWhile = true; ;?im(9h"v!  
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for(int i=0;i<nStartPos.length;i++) '\4fU%  
{ =jIxI,  
if(!fileSplitterFetch.bDownOver) ~PUsgL^  
{ ec?1c&E  
breakWhile = false; mq`5w)S)\o  
break; SL*DK.  
} 0_V*B[V  
} 7jezw'\=~  
if(breakWhile) j6X LyeG7  
break; $
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T{ nQjYb?  
//count++; 3LfTGO  
//if(count>4) 9 x [X<  
// siteStop(); T5{T[YdX<  
} JFJIls  
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System.err.println("文件下载结束！"); AFtCqq#[  
} -y<x!61  
catch(Exception e){e.printStackTrace ();} '^lUL) R  
} T+BIy|O  
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p[;8  
//获得文件长度 P7Z<0Dt\}  
public long getFileSize() 7BrV<)ih{*  
{ ?k w/S4  
int nFileLength = -1; {*nEKPq(_*  
try{ \vs%U}IrO  
URL url = new URL(siteInfoBean.getSSiteURL()); (JvQ-H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wV %8v\  
httpConnection.setRequestProperty("User-Agent","NetFox"); g?$e^ls  
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+QQYPEx+  
int responseCode=httpConnection.getResponseCode(); Dwk$CJ
b3-  
if(responseCode>=400) <q1'Li)_R  
{ FB.!`%{  
processErrorCode(responseCode); xtu]F  
return -2; //-2 represent access is error HD~jU>}}  
} mj,qQ=n;p  
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String sHeader; 6BR\iZ  
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for(int i=1;;i++) vsw7|  
{ 9DY|Sa]#=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f^ywW[dF  
//Utility.log(in.readLine()); ^$8Vh=D  
sHeader=httpConnection.getHeaderFieldKey(i); `6n!$Cxo  
if(sHeader!=null) dqL-'  
{ mC%%)F'Zf  
if(sHeader.equals("Content-Length")) EK:Y2WZ  
{ #efqG=q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %zRiLcAT  
break; @\S]]oLn  
} )Xq@v']%~9  
} $:PF9pY(  
else 91U^o8y  
break; tru;;.lj8K  
} `X3Xz!  
} .Kg|f~InO  
catch(IOException e){e.printStackTrace ();} y4 dp1<t%  
catch(Exception e){e.printStackTrace ();} -??!@R7V  
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Utility.log(nFileLength); 3j]UEA^  
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return nFileLength; QQ5
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} e~tr^$/(  
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//保存下载信息（文件指针位置） E~rs11  
private void write_nPos() D)f5pEq'  
{ *4r s  
try{ L`<T'3G  
output = new DataOutputStream(new FileOutputStream(tmpFile)); r'Hy}HWuF  
output.writeInt(nStartPos.length); Qx9>,e6+  
for(int i=0;i<nStartPos.length;i++) ._8xY$l$  
{ =}B4I  
// output.writeLong(nPos); 5xG|35Pj  
output.writeLong(fileSplitterFetch.nStartPos); =)mXCA^  
output.writeLong(fileSplitterFetch.nEndPos); ({D}QEP  
} <O <'1uO,  
output.close(); e6tH/`Uln  
} Z?!JV_K  
catch(IOException e){e.printStackTrace ();} KK&<Vw|O\  
catch(Exception e){e.printStackTrace ();} 5KL9$J9k  
} |V5$'/Y  
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//读取保存的下载信息（文件指针位置） owfp^hla  
private void read_nPos() pDLu+}@  
{ 3K=q)|  
try{ V6DBKq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mB{&7Rb0  
int nCount = input.readInt(); *F26}q  
nStartPos = new long[nCount]; : ;E7+m  
nEndPos = new long[nCount]; [4K9|/J  
for(int i=0;i<nStartPos.length;i++) Fg
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{ w^:V."}-$  
nStartPos = input.readLong(); +cPE4(d  
nEndPos = input.readLong(); *`@XKK  
} 3{2^G@j  
input.close(); Q1O_CC}  
} 0?J|C6XM#4  
catch(IOException e){e.printStackTrace ();} BCj`WF@8l{  
catch(Exception e){e.printStackTrace ();} 3*X,{%  
} Rye~w6  
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private void processErrorCode(int nErrorCode) \-$bo=s.  
{ 0Y38T)k  
System.err.println("Error Code : " + nErrorCode); =sUl`L+w,L  
} =|qt!gY)Y  
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//停止文件下载 uFm(R/V  
public void siteStop() zAkc67:  
{  Gh)sw72  
bStop = true; 6)uPM"cO  
for(int i=0;i<nStartPos.length;i++) U- *8%>Qp
 
fileSplitterFetch.splitterStop(); #x4h_K Y  

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} dIBKE0`  
} Kc2OLz#  
//负责部分文件的抓取 E&s'uE=w+  
**FileSplitterFetch.java JA SR  
*/ 'Ec:l(2Ec  
package NetFox; M<#)D  
[6&CloY3  
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import java.io.*; w$(0V$l_  
import java.net.*; },Re5W nl  
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public class FileSplitterFetch extends Thread { B:6sVJ  
n}9Msen  
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String sURL; //File URL T$.-{I  
long nStartPos; //File Snippet Start Position aCYm$6LmA  
long nEndPos; //File Snippet End Position j J`Zz  
int nThreadID; //Thread's ID .j:.WnW  
boolean bDownOver = false; //Downing is over k8x&aH  
boolean bStop = false; //Stop identical U Qi^udGFD  
FileAccessI fileAccessI = null; //File Access interface }!Diai*C  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException VhH]n yi7D  
{ f,`}hFD  
this.sURL = sURL; pw<q?q%  
this.nStartPos = nStart;  i_E#cU  
this.nEndPos = nEnd; +2au ;^N  
nThreadID = id; 4
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 fN"oa>X  
} }x#P<d(  
{Hp}F!X$  
)
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public void run() ?CT^Zegmr  
{ $?/Xk%d+  
while(nStartPos < nEndPos && !bStop) X!+Mgh6  
{
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try{ |jaY[_.@  
URL url = new URL(sURL); :oj) eS[Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [P&,}o)+E0  
httpConnection.setRequestProperty("User-Agent","NetFox"); Er/5 ,  
String sProperty = "bytes="+nStartPos+"-"; gh #w%g1g  
httpConnection.setRequestProperty("RANGE",sProperty); }D
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Utility.log(sProperty); pv m'pu78  
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InputStream input = httpConnection.getInputStream(); @X6#$ex  
//logResponseHead(httpConnection); ;\*Od?1  
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byte[] b = new byte[1024]; 
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int nRead; <<2b2?aS`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :D+SY  
{ ^n45N&916  
nStartPos += fileAccessI.write(b,0,nRead); *r?51
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//if(nThreadID == 1) /XW0`FF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @H# kvYWmn  
} dzv,)X  
>3 .ep},  
4tTZkJc  
Utility.log("Thread " + nThreadID + " is over!"); SQKY;p  
bDownOver = true; U)/Ul>dY
 
//nPos = fileAccessI.write (b,0,nRead); / ?[gB:s  
} np\Q&  
catch(Exception e){e.printStackTrace ();} "g:&Ge*X  
} ])wMUJWg2  
} ]o+|jgkt]  
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//打印回应的头信息 +e]b,9.sR  
public void logResponseHead(HttpURLConnection con) .sR&9FH  
{ '=b&)HbeK  
for(int i=1;;i++) 8m[L]6F(-z  
{ .9fluAG  
String header=con.getHeaderFieldKey(i); DF
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if(header!=null) iCSM1W3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3Q
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Utility.log(header+" : "+con.getHeaderField(header)); ,sJfMY  
else 6dy4
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break; 75}u D  
} .x$T al  
} KP7RrgOan&  
*4^]?Y\*  
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public void splitterStop() /b
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{ iY'hkrw  
bStop = true; XXwhs-:o  
} f$W}d0(F;  
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} x15t
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/* &q}@[ )V4  
**FileAccess.java }Z?[Ut  
*//文件访问(定位，写) #Ii.tTk  
package NetFox; BBJ]>lQ  
import java.io.*; h>%JG'DV  
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%R"/`N9R,  
public class FileAccessI implements Serializable{ *g41"Cl  
v 4b`19}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r8?Lr-;  
RandomAccessFile oSavedFile; #*M$,ig  
long nPos; =pOY+S|  
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public FileAccessI() throws IOException P]
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{ 64>[pZF8  
this("",0); t-(7Q8(  
} W}_}<rlF  
H 7F~+Q-}  
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public FileAccessI(String sName,long nPos) throws IOException RX\O'Zwlj  
{ W1`ZS*12D  
oSavedFile = new RandomAccessFile(sName,"rw"); 76r s)J[*w  
this.nPos = nPos; :Qp/3(g e  
oSavedFile.seek(nPos); k$_]b0D{4  
} G&3<rT3Ib  
"FIx^  
3 v$
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public synchronized int write(byte[] b,int nStart,int nLen) Zs|sPatV<  
{ eSBf;lr=  
int n = -1; h5keYBA  
try{ 6lAo`S\)eX  
oSavedFile.write(b,nStart,nLen); bK1`a{  
n = nLen; (UT*T  
} {*$J&{6V  
catch(IOException e) B:.;:AEbT  
{ kP@OIhRe  
e.printStackTrace (); 2A ,36,  
} Cjk AQ(9  
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return n; I>Yp=R  
} ..TjEBp  
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} 5c7a\J9>  
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/* [KJL%u|8/  
**SiteInfoBean.java Sxu v}y\  
*/ dS=,. }  
package NetFox; xyz86r ^u  
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public class SiteInfoBean { U.(_n  
}!Lr!eALr  
Q
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private String sSiteURL; //Site's URL j=S"KVp9NF  
private String sFilePath; //Saved File's Path K$]B" s  
private String sFileName; //Saved File's Name 9E?>B3t^  
private int nSplitter; //Count of Splited Downloading File *?fBmq[j  
9V\`{(R  
# t Ki6u  
public SiteInfoBean() `BD`pa7.%  
{//nSplitter的缺省值为5 ev >9P  
//default value of nSplitter is 5 9
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this("","","",5); ^]gl#&"D  
} Z U
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rID]!7~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ek!N eu>  
{ GXVGU-br  
sSiteURL= sURL; Yg.u8{H  
sFilePath = sPath; ?K 0V#aq  
sFileName = sName; C\D4C]/8  
this.nSplitter = nSpiltter; pE,BE%
 
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} tm?  
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`^vD4qD|  
public String getSSiteURL() Q-5wI$=  
{ %xz02$k  
return sSiteURL; Cj9Tj'0@I+  
} iI0'z=J  
'QU ?O[CH  
o9>X"5CmX  
public void setSSiteURL(String value) OQvJdjST  
{ etVE8N'  
sSiteURL = value; owhht98y(  
} >0oc=9H8  
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nE84W$\  
public String getSFilePath() r_m&Jl@4  
{ 3RUB2c4  
return sFilePath; z16++LKmM  
} is$d<Y&F  
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public void setSFilePath(String value) {5h_$a!TaU  
{ w?q"%F;/  
sFilePath = value; )Be;Zw.|  
} J4i0+u  
N}=-+E|  
]\U'_G2]  
public String getSFileName() }f}&|Vap  
{ qDW/8b\^  
return sFileName; =[&Jxy>Y  
} 4dP_'0]9A:  
iDsjIW\j  
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public void setSFileName(String value) C#R9Hlb  
{ -E1}mL}I`  
sFileName = value; a=R-F!P)  
} p:jrqjLp  
 ^8iy(  
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public int getNSplitter() %y q}4[S+o  
{ ~nQb;Bdh%  
return nSplitter; r[x7?cXsW  
} DH%X+r  
.\ZxwD|  
/<@tbZJ*8  
public void setNSplitter(int nCount) ]nh)FMo  
{ tdm /U  
nSplitter = nCount; EA\~m*k  
} 7o<RvM  
} C1J'. !  
q3:tZoeXV  
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/* 3]i1M%'i  
**Utility.java g;pFT  
*/ *K;~V  
package NetFox; @."R9s  
B06/mKZ7  
]:;gk&P  
public class Utility {
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(:1j-  

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public Utility() 5>HI/QG  
{ qv:WC TAn  
}\W3a_,v)  
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} 3Wiu`A  
MI/1uw  
//线程睡眠 _heQ|'(  
public static void sleep(int nSecond) mXr)lA  
{ 6Z$T&Ul{  
try{ EQ28pAZ  
Thread.sleep(nSecond); *VH1(E`hl  
} ,O2F}5|;  
catch(Exception e) 0V^?~ex  
{ WIg"m[aIs  
e.printStackTrace (); (<ejJPWT  
} L{42?d  
} DeUDZL%/  
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//日志 N5_v}<CN  
public static void log(String sMsg) 4avM:h  
{ gnv4.f:  
System.err.println(sMsg); &(K*TB|Om  
} ~&pk</Dl  
 -x7L8Wj  
+,smjg:O  
public static void log(int sMsg) K46\Rm_:B;  
{ k: {$M yK  
System.err.println(sMsg); ISl'g'o  
} {f!mm3'2v  
} t~Uqsa>n@'  
htjJ0>
&  
8Vq,J:+  
/* ^}WeBU  
**TestMethod.java Q/< $ (Y  
*/ AIE)q]'Q  
package NetFox; A81kb  
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public class TestMethod { Bp}<H<@  
ZXco5,1  
f[.]JC+,  
public TestMethod() U $+rlw}  
{ ///xx/weblogic60b2_win.exe 
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try{
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `+<5QtD  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [p]Ayo$~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); W2n%D& PE  
fileFetch.start();  @]A4{  
} I3SLR  
catch(Exception e){e.printStackTrace ();} r+) A)a,  
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} }ulFW]A^7  
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public static void main(String[] args) w7O(I"  
{ iX4/;2B=,  
new TestMethod(); f~E'0f_  
} d(h`bOjI  
} eX}uZR  
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