http断点续传简单实现（java)

/* oWL_Hh%-f`  
**SiteFileFetch.java tnaFbmp  
*/ 'St6a*  
package NetFox; &:g:7l]g  
import java.io.*; 3PGAUQR#"q  
import java.net.*; }a$.ngP  
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public class SiteFileFetch extends Thread { +x=)Kp>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean l@Vv%w9H  
long[] nStartPos; //开始位置 '"fJA/O  
long[] nEndPos; //结束位置 V-}}?c1 F  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gr SF}y!3  
long nFileLength; //文件长度 !CWe1Dm  
boolean bFirst = true; //是否第一次取文件 @2/|rq  
boolean bStop = false; //停止标志 nq]6S$3 6  
File tmpFile; //文件下载的临时信息 >4jE[$p]"  
DataOutputStream output; //输出到文件的输出流 Q0Ft.b  
A vq+s.h  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） N o6!gZ1  
public SiteFileFetch(SiteInfoBean bean) throws IOException a&x:_vv  
{ &jHsFS  
siteInfoBean = bean; U_(>eVi7F  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s:}?rSI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Sy|GM~  
if(tmpFile.exists ()) ![\-J$  
{ \4q|Qno8  
bFirst = false; )Xjn:  
read_nPos(); _ \6v
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} xKG7d8=  
else M_};J;  
{ (c(F1=K  
nStartPos = new long[bean.getNSplitter()]; x/umwT,ov  
nEndPos = new long[bean.getNSplitter()]; 4u6 FvN  
} ::oFL#+  
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} v 49o$s4J  
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public void run() 2bNOn%!  
{ HeAXZA,  
//获得文件长度 LpU}.  
//分割文件 Q v9q~l  
//实例FileSplitterFetch 3F2IL)Hn  
//启动FileSplitterFetch线程 'RMUjJ-!  
//等待子线程返回 ^)H
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try{ %+(AKZu:  
if(bFirst) D*%am|QL  
{ :Z//  
nFileLength = getFileSize(); ( 2HM"Pd  
if(nFileLength == -1) .>B'oD  
{ N `|A  
System.err.println("File Length is not known!"); KS$t  
} u#@/^h;  
else if(nFileLength == -2) VGV-t  
{ $N=&D_Q  
System.err.println("File is not access!"); t)zd'[  
} D~6[C:m  
else I\.|\^  
{ zqeQ  
for(int i=0;i<nStartPos.length;i++) 86r"hy~  
{ k&dXK  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); egaX[j r  
} }%_|k^t  
for(int i=0;i<nEndPos.length-1;i++) ~rb0G*R>  
{ |p6d]#z3  
nEndPos = nStartPos[i+1]; V.GM$  
} -+*h'zZ[<w  
nEndPos[nEndPos.length-1] = nFileLength; iHD!v7d7  
} KZ
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} #rlgeHG!fs  
BsQ;`2  
*G58t`]r  
//启动子线程 f7=MgFi  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C*Vm}|)  
for(int i=0;i<nStartPos.length;i++) URsx>yx  
{ ]cpb;UfM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }_D.Hy5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QQl.5'PP  
nStartPos,nEndPos,i); cJo%j -AM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -r\jIO_  
fileSplitterFetch.start(); "V|Rq]_+%  
} UQl?
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q0xO;20  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); C]ss'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", yYCS-rF>  
nEndPos = " + nFileLength); 8}'iEj^e  
// fileSplitterFetch[nPos.length-1].start(); qOo4T@t3  
;+hh|NiQ  
{T4_Xn
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//等待子线程结束 7
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//int count = 0;
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//是否结束while循环 !l'nX  
boolean breakWhile = false; Px_8lB/;  
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while(!bStop) :\;9y3  
{ , 'pYR]3  
write_nPos(); ?@"@9na  
Utility.sleep(500); 6r
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breakWhile = true; B7\4^6T
x  
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for(int i=0;i<nStartPos.length;i++) j7P49{  
{ lS=YnMs6a  
if(!fileSplitterFetch.bDownOver) :w^:Z$-hf  
{ 3p#UEH3  
breakWhile = false; x?Sx cQP  
break; ().C
  
} MfQ0O?oBp  
} 2"6L\8hd2  
if(breakWhile) c^|8qv
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break; sUF$eVAT  
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//count++; ZcA"HD%  
//if(count>4) Ec7xwPk  
// siteStop(); *JOK8[Qn  
} ]yOM  
r'i99~  
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System.err.println("文件下载结束！"); HG7Qdw2+O  
} ihkZs3}  
catch(Exception e){e.printStackTrace ();} h#zm+([B*  
} zfUDo`V~  
&^ERaPynd  
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//获得文件长度 hTBJ
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public long getFileSize() q
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{ &tOo[U?  
int nFileLength = -1; !+$qSD,%x  
try{ i7H([b<_m  
URL url = new URL(siteInfoBean.getSSiteURL()); c:${qY:!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wi$?k{C  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6UIS4_   
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int responseCode=httpConnection.getResponseCode(); $(&uaDYv  
if(responseCode>=400) ~Dg:siw  
{ Z@q1&}D!  
processErrorCode(responseCode); .UxkTads  
return -2; //-2 represent access is error }ll&EB  
} ,5 ,r.  
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String sHeader; hbXmIst  
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for(int i=1;;i++) s\.r3U&6  
{ 2zo>`;l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c%<81Y=  
//Utility.log(in.readLine()); , wk}[MF  
sHeader=httpConnection.getHeaderFieldKey(i); hj=n;,a9  
if(sHeader!=null) covCa)kf  
{ z%fjG}z  
if(sHeader.equals("Content-Length")) i(rYc  
{ ?(s9dS,7wZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Jn(|.eT|  
break; O-AC$C[d  
} aeMj4|{\  
} E:}s6l  
else Njo.-k  
break; L `2{H%J`  
} dsEvpa$
?  
} F, =WfM\  
catch(IOException e){e.printStackTrace ();} xqT} 9,  
catch(Exception e){e.printStackTrace ();} b#709VHm  
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Utility.log(nFileLength); 6hcs)X7m  
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return nFileLength; N]BH67<  
}  w&U28"i>  
:hHKm|1FE  
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//保存下载信息（文件指针位置） 5G<`c  
private void write_nPos() *<9M|H~  
{ SOD3MsAK  
try{ 1\TkI=N3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); B \V;{:  
output.writeInt(nStartPos.length); c3fd6Je5  
for(int i=0;i<nStartPos.length;i++) x}C$/7^  
{ (>Sy,  
// output.writeLong(nPos); 1\jj3Y'i'  
output.writeLong(fileSplitterFetch.nStartPos); $SLyI$<gP  
output.writeLong(fileSplitterFetch.nEndPos); [CnoMN  
} ubl Y%{"  
output.close(); j%!xb><  
} IFSIQ q  
catch(IOException e){e.printStackTrace ();} 0s4]eEXH  
catch(Exception e){e.printStackTrace ();} gYL#} )g  
} &S^a_L:  
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|$T?P*pI.  
//读取保存的下载信息（文件指针位置） Gy
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private void read_nPos() dDe$<g5L4  
{ qE^u{S4Z@  
try{ 8LtkP&Wx  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Lz-(1~o  
int nCount = input.readInt(); 17rg!'+   
nStartPos = new long[nCount]; 5Shc$Awc!  
nEndPos = new long[nCount]; (i)O@Jve  
for(int i=0;i<nStartPos.length;i++) \a:-xwUu<  
{ u_=>r_J[b  
nStartPos = input.readLong(); t-FrF</0  
nEndPos = input.readLong(); \n0Gr\:  
} ZYl*-i&~?  
input.close(); QswFISch
 
} uCFpH5>  
catch(IOException e){e.printStackTrace ();} 'kCr1t  
catch(Exception e){e.printStackTrace ();} *xKY>E+  
} f<DqA/$  
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private void processErrorCode(int nErrorCode) M/6q ^*  
{ `?"[u"*  
System.err.println("Error Code : " + nErrorCode); *=QWx[K|  
} U_0"1+j
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//停止文件下载 &-.2P!t  
public void siteStop() !"^//2N+,  
{ +_fxV|}P  
bStop = true; kEdAt5/U{  
for(int i=0;i<nStartPos.length;i++) 62OZj%CXN  
fileSplitterFetch.splitterStop(); &ZPyZj  
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} gDsb~>rb|  
} /9u12R*<  
//负责部分文件的抓取 \g;-q9g;O  
**FileSplitterFetch.java [M.!7+$o  
*/ _%aJ/Y0Cy  
package NetFox; P_c9v/  
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import java.io.*; z!\)sL/"  
import java.net.*; &q[`lIV,L  
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public class FileSplitterFetch extends Thread { ~LN {5zg  
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String sURL; //File URL ~d6zpQf7>  
long nStartPos; //File Snippet Start Position y[:xGf]8@  
long nEndPos; //File Snippet End Position #ruL+-8!<  
int nThreadID; //Thread's ID +,ZQ( ZW  
boolean bDownOver = false; //Downing is over z)y{(gR  
boolean bStop = false; //Stop identical (ft$ R?  
FileAccessI fileAccessI = null; //File Access interface [,ns/*f3R  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Hk|wO:7
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{ g~$cnU  
this.sURL = sURL; GZqy.AE,  
this.nStartPos = nStart; xrl!$xE GX  
this.nEndPos = nEnd; b\Gw|?Rv  
nThreadID = id; DlbNW& V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w57D qG>  
} L(qQ,1VY  
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public void run() Wi{ jC?2Q  
{ EJ`"npU  
while(nStartPos < nEndPos && !bStop) wtnC^d$  
{ Bgj^n{9x  
<MBpV^Y}  
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try{ a{7'qmN1  
URL url = new URL(sURL); V17SJSC-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $4&e{fLt|v  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vu_QwWXO  
String sProperty = "bytes="+nStartPos+"-"; ;sn]Blpq  
httpConnection.setRequestProperty("RANGE",sProperty); S U$U  
Utility.log(sProperty); leJ\  
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InputStream input = httpConnection.getInputStream(); N3g\X
  
//logResponseHead(httpConnection); 5ki<1{aVtZ  
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byte[] b = new byte[1024]; +&h<:/ V  
int nRead; vCS D1~V_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P<A_7Ho  
{ /V@9!  
nStartPos += fileAccessI.write(b,0,nRead); R<n'v.~"A  
//if(nThreadID == 1) xF8^#J6>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m_g2Cep  
} Sr?2~R0&  
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Utility.log("Thread " + nThreadID + " is over!"); ij+)U`  
bDownOver = true; L1J~D?q  
//nPos = fileAccessI.write (b,0,nRead); &;]KntxB  
} Doj>Irj?7  
catch(Exception e){e.printStackTrace ();} U sS"WflB  
} YA[\|I33  
} V 0M&D,  
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//打印回应的头信息 !5XH.DYq!  
public void logResponseHead(HttpURLConnection con) +l)[A{  
{ jC}2>_#m(  
for(int i=1;;i++) eN{ewn#0.  
{ #<*=)[  
String header=con.getHeaderFieldKey(i); VY|'7in"M  
if(header!=null) D@ 4sq^|2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?)V?6"fFP  
Utility.log(header+" : "+con.getHeaderField(header)); DO{Lj#@  
else |Jpi|'  
break; tR`^c8gD  
} UOYhz.  
} [wv;CUmgc  
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public void splitterStop() %("WoBPH`  
{ cfhiZ~."T  
bStop = true; ' |Ia-RbX  
} G'IRqO*]  
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} s9F{UN3  
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/*  Xn=  
**FileAccess.java G{]tB w  
*//文件访问(定位，写) >\4"k4d}  
package NetFox; sX[k}=HCK  
import java.io.*; (t_%8Eu  
/:-Y7M*  
'Hv=\p4$1  
public class FileAccessI implements Serializable{ q>f|1Pf  
X]+z:!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,0\Pr  
RandomAccessFile oSavedFile; mZ0'-ax   
long nPos; BBDt^$  
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public FileAccessI() throws IOException |{ TVW  
{ %@'[g]hk  
this("",0); wrm ReT?  
} (,^jgv|I  
D*}_

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public FileAccessI(String sName,long nPos) throws IOException Q/]t$  
{ u{8:VX  
oSavedFile = new RandomAccessFile(sName,"rw"); wn/Y5   
this.nPos = nPos; #,CK;h9jy!  
oSavedFile.seek(nPos); AR3v,eOs  
} ;/ASl<t,  
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public synchronized int write(byte[] b,int nStart,int nLen) uy rS6e0  
{ nA#N,^Rr  
int n = -1; sh)[|?7
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try{ oef]  
oSavedFile.write(b,nStart,nLen); )MeeF-Ad6  
n = nLen; /pQUu(~h_  
} Ef\&3TcQ  
catch(IOException e) /Y0oA3am  
{ w)Z-, J  
e.printStackTrace (); RYZM_@5$t  
} a/TeBx#yG  
^*'fDP*  
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return n; $ #bWh  
} 
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c"
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} e)f!2'LL  
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/* =4#p|
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**SiteInfoBean.java l5FKw;=K}:  
*/ IiM=Z=2  
package NetFox; 3XcFBFE  
{]Ec:6  
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public class SiteInfoBean { R 6 -RH7.  
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,A[NcFdCB  
private String sSiteURL; //Site's URL W.nr&yiQ  
private String sFilePath; //Saved File's Path v~:'t\n  
private String sFileName; //Saved File's Name :&J1#% t  
private int nSplitter; //Count of Splited Downloading File -0>s`ruor  
->)0jZax  
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public SiteInfoBean() O"9Or3w  
{//nSplitter的缺省值为5 Bmv5yc+;  
//default value of nSplitter is 5 |h-e+Wh1  
this("","","",5); @+yjt'B  
} M.``o1b  
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?{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @dc4v_9  
{ {r
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sSiteURL= sURL;  L0>7v  
sFilePath = sPath; WZN0`Od  
sFileName = sName; e]@ B61lc  
this.nSplitter = nSpiltter; ^_t7{z%sA[  
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} uJU;C.LX  
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public String getSSiteURL() C4K"eX,K  
{ lyw)4;wt\  
return sSiteURL; gg@Ew4L&  
} [/U5M>#n  
SI/3Dz[  
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public void setSSiteURL(String value) R= .UbY  
{ /mwsF]Y  
sSiteURL = value; J<MuWgx&  
} KJW^pAj$B  
jdd3[  
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public String getSFilePath() UcWf O!}D  
{ ^&\<[\  
return sFilePath; m%U$37A1  
} Q1RUmIe_&  
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H](TSt<Q"  
public void setSFilePath(String value) s]Z++Lh<{  
{ ql7N\COoq  
sFilePath = value; t;W'<.m_  
} Cf.(/5X  
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public String getSFileName() )<`/Aaie  
{ w_*$wVl
 
return sFileName; /;WFRp.  
} X4/3
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e?<$H\  
public void setSFileName(String value) dC?l%,W  
{ lh-zE5;  
sFileName = value; }@vf=jm>  
} @wh-.MD  
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e/zz.cd){  
public int getNSplitter() ;
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{ K}QZdN']  
return nSplitter; ?GGBDql  
} +K48c,gt?  
}*VRj;ff  
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public void setNSplitter(int nCount) e
\! ic  
{ .x_F4#Ka  
nSplitter = nCount; |fPR7-  
} R2y~+tko?
 
} RC^k#+  

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/* EB8<!c ?  
**Utility.java *P+8^t#Vp  
*/ Im@Yx^gc  
package NetFox; g4GU
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public class Utility { c@{M),C~E  
@Wd1+Yky  
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public Utility() }XfRKGQw  
{ Fr1OzS^&(  
v+ "9&  
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} m>+e;5  
i"#zb&~nF  
//线程睡眠 xDIl  
public static void sleep(int nSecond) H'x_}y  
{ A&:~dZ:%w  
try{ teJY*)d  
Thread.sleep(nSecond); J pKCux  
} o_PQ]1  
catch(Exception e) [#/@v/`  
{
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e.printStackTrace (); 8:jakOeT  
} bP{uZnOM2P  
} w>&g'  
RNb"O{3  
//日志 PRN%4G  
public static void log(String sMsg) e# KP3Lp  
{ rG{,8*  
System.err.println(sMsg); pR3K~bx^  
} ;%4N@Z  
c)zwyBz  
xN44>3#  
public static void log(int sMsg) 2UEjn>2  
{ &Tk@2<5=  
System.err.println(sMsg); @!%HEs!# #  
} h F *c  
} A'T: \Wl  
en29<#8TO  
d.p%jVO)"  
/* ;a`I8Fj  
**TestMethod.java w'<"5F`  
*/ ^zR*s |1Q  
package NetFox; h2vD*W  
>\Ml\CyL  
_[S<Cb*1  
public class TestMethod { ^4{"h  
y\<\P8X  
>?GCH(eW%  
public TestMethod() Uw->5   
{ ///xx/weblogic60b2_win.exe HI{IC!6  
try{ r$&WwH2^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /xkF9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Pa */&WeB  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w>6cc#>q  
fileFetch.start(); kTm>`.kKJ=  
} zl@hg<n  
catch(Exception e){e.printStackTrace ();} ]McDN[h:  
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_:VIlg U  
} 1g_Dkv|D  
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public static void main(String[] args) 0R}F(tjw  
{ E>k!d'+tb  
new TestMethod(); Mt%=z9OLq9  
} NnqAr ,  
} &``nYI g/  
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