http断点续传简单实现（java)

/* $k@O`xD,q  
**SiteFileFetch.java k$z_:X  
*/ ?>D+ge  
package NetFox; G\/zkrxmv  
import java.io.*; Zw 26  
import java.net.*; IXMop7~  
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public class SiteFileFetch extends Thread { knu,"<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean qOIyub  
long[] nStartPos; //开始位置 1y4|{7bb  
long[] nEndPos; //结束位置 }WC[$Y_@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 nMq,F#`3N  
long nFileLength; //文件长度 KVoS C@w  
boolean bFirst = true; //是否第一次取文件 !=*g@mgF  
boolean bStop = false; //停止标志 sQUM~HD\a  
File tmpFile; //文件下载的临时信息 ="1Ind@w!  
DataOutputStream output; //输出到文件的输出流 MnsJEvn/  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） E<{R.r  
public SiteFileFetch(SiteInfoBean bean) throws IOException <.x{|p  
{ Thp[+KP>  
siteInfoBean = bean; p,5i)nEFj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Go`vfm"S  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e8>})  
if(tmpFile.exists ()) A2I9R;}  
{ lLX4Gq1  
bFirst = false; ,uSMQS-O'4  
read_nPos(); oA7tEu   
} GvtG(u~  
else O40?{v'  
{ lK?uXr7^  
nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()]; pz!Zs."f)
 
} 2RVN\?s:  
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} g+8OekzB5  
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public void run() Q,,e+exbb5  
{
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//获得文件长度 bQzZy5,  
//分割文件 xeg/
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//实例FileSplitterFetch e@L=LW>  
//启动FileSplitterFetch线程
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//等待子线程返回 x77*c._3v  
try{ !{+,B5 Hc  
if(bFirst) t>
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{ Q
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nFileLength = getFileSize(); JinU
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if(nFileLength == -1) \0^Kram>
 
{ 70yFaW  
System.err.println("File Length is not known!"); fF!Yp iI"  
} h/QXPdV  
else if(nFileLength == -2) qJf
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{ poc`q5i+  
System.err.println("File is not access!"); _>o:R$ %}  
} w1FcB$  
else {X!r8i  
{ =}<IfNA  
for(int i=0;i<nStartPos.length;i++) 3<e=g)F  
{ Yj<a" Gr4[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7m47rJyW4  
} bt@< ut\  
for(int i=0;i<nEndPos.length-1;i++) vOH4#  
{ XnH05LQ  
nEndPos = nStartPos[i+1]; 3p$?,0ELH  
} @JiLgIe`  
nEndPos[nEndPos.length-1] = nFileLength; 0.Q Ujw  
} %HhBt5w  
} pN,u
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//启动子线程 k`cfG\;r  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; F0m-23[H  
for(int i=0;i<nStartPos.length;i++) Gf%~{@7=u  
{ c^5~QGuQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4V"E8rUL(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3#n_?-  
nStartPos,nEndPos,i); O"+gQXe  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kl"hBK#D%  
fileSplitterFetch.start(); "-Mp_O]  
} m=1N>cq '  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w$>u b@=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8:q1~`?5"b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %6t
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nEndPos = " + nFileLength); ./XYd"p  
// fileSplitterFetch[nPos.length-1].start(); Ml`:UrU  
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cQjv$$&6[  
//等待子线程结束 +Z,;,5'5G  
//int count = 0; H
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//是否结束while循环 #QZe,"C9`  
boolean breakWhile = false; 5frX  
9v#CE!  
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while(!bStop) :S]\0;8]  
{ ,10=  
write_nPos(); wC"FDr+  
Utility.sleep(500); M+oHtX$  
breakWhile = true; XjBW9a  
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for(int i=0;i<nStartPos.length;i++) y1z4ik)Sd@  
{ ufj,T7g^  
if(!fileSplitterFetch.bDownOver) AI2~Jp  
{ EX*HiZU>  
breakWhile = false; 4a&RYx  
break; t <~h'U  
} >:SHV W  
} PhLn8jNti  
if(breakWhile) Q(
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break; pt?bWyKG  
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//count++; L]7=?vN=8  
//if(count>4)
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// siteStop(); )w em|:H  
} rDtY[  
=&6eM2>P  
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System.err.println("文件下载结束！"); :S]%6gb8G  
} ;J'LS  
catch(Exception e){e.printStackTrace ();} 1> ?M>vK  
} n>z9K')  
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//获得文件长度 ,};&tR  
public long getFileSize() Y!xF;a  
{ Fk
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int nFileLength = -1; "> ypIR<  
try{ t[HE6ea  
URL url = new URL(siteInfoBean.getSSiteURL()); VD AaYDi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "37lx;CH  
httpConnection.setRequestProperty("User-Agent","NetFox"); _=r6=.  
/*~EO{o  
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int responseCode=httpConnection.getResponseCode(); Q)#B0NA;T  
if(responseCode>=400) SZ7:u895E  
{ ?9vuuIE  
processErrorCode(responseCode); m<G,[Yc  
return -2; //-2 represent access is error Lpkyoh v  
} t mntp
 
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String sHeader; alJ)^OSIe  
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for(int i=1;;i++) _>?\DgjH  
{ xh-o}8*n"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z9f-.72"X  
//Utility.log(in.readLine()); /A\8 mL8  
sHeader=httpConnection.getHeaderFieldKey(i); (le9q5Qr.  
if(sHeader!=null) Bg=wKwc8  
{ =}^9 wP  
if(sHeader.equals("Content-Length")) AD>e?u  
{ uo:J\E  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); qw301]y  
break; 299H$$WS,Z  
} !vi>U|rh  
} b1q"!+8y  
else j8i[ONq^  
break; >I
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} d7^}tM  
} $GV7o{"&  
catch(IOException e){e.printStackTrace ();} 63iUi9P  
catch(Exception e){e.printStackTrace ();} MR7}s4o  
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Utility.log(nFileLength); o)|flI'vT  
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return nFileLength; <\y@*fg+  
} wSL}`CgU  
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//保存下载信息（文件指针位置） x^qVw5{n  
private void write_nPos() eu|YCYj)g  
{ y8Ir@qp5  
try{ >h1}~jW+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hF?1y`20  
output.writeInt(nStartPos.length); 1#g2A0U,  
for(int i=0;i<nStartPos.length;i++) J(TkXNm  
{ jwe*(k]z  
// output.writeLong(nPos); lgAoJ[  
output.writeLong(fileSplitterFetch.nStartPos); g9p
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output.writeLong(fileSplitterFetch.nEndPos); h f)?1z4  
} OnziG+ak  
output.close(); $p8xEcQdU#  
} T~?Ff|qFC  
catch(IOException e){e.printStackTrace ();} ' {OgN}'{  
catch(Exception e){e.printStackTrace ();} T"Y+m-<%  
} v~+(GqR=+  
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//读取保存的下载信息（文件指针位置） # +>oZWVc  
private void read_nPos() ldcqe$7,  
{ 68|E9^`l  
try{ S\EyCi+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
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int nCount = input.readInt(); ITQA0PISL  
nStartPos = new long[nCount]; w(Ovr`o?9t  
nEndPos = new long[nCount]; )}R0Y=e  
for(int i=0;i<nStartPos.length;i++) yN0Vr\r2  
{ KkyVSoD\  
nStartPos = input.readLong(); }Bh8=F3O Q  
nEndPos = input.readLong(); Y Uc+0  
} pad*oPH,  
input.close(); s+Pq&<nV-  
} "^[ 'y7i  
catch(IOException e){e.printStackTrace ();} bP#:Oi0v`  
catch(Exception e){e.printStackTrace ();} NYUL:Tp  
} v"$L702d$\  
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private void processErrorCode(int nErrorCode) (Rh,,  
{ 2"Q|+-Io  
System.err.println("Error Code : " + nErrorCode); /N+dQe  
} @7c?xQVd$  
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//停止文件下载 (/YHk`v2  
public void siteStop() ]
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{ F<1fX7c  
bStop = true; p>N(Typ0b  
for(int i=0;i<nStartPos.length;i++) *R,5h2;  
fileSplitterFetch.splitterStop(); `hm-.@f,9  
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} }K>d+6qk5  
} \K{ z  
//负责部分文件的抓取 iMh#TUlQEQ  
**FileSplitterFetch.java tjS@meT  
*/ GA)`-*.R  
package NetFox; C=xa5Y  
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import java.io.*; 1~FOgk1;  
import java.net.*; rHI{aO7  
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public class FileSplitterFetch extends Thread { jd"@t*ZV  
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String sURL; //File URL Vt~{
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long nStartPos; //File Snippet Start Position Pm?KI<TH~  
long nEndPos; //File Snippet End Position (E3b\lST  
int nThreadID; //Thread's ID y<3-?}.aZ  
boolean bDownOver = false; //Downing is over #z%fx
 
boolean bStop = false; //Stop identical est9M*Fn  
FileAccessI fileAccessI = null; //File Access interface Kw
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Lb-OsKU  
{ G4;Oi=  
this.sURL = sURL; {TROoX~H?  
this.nStartPos = nStart; *>}@7}f  
this.nEndPos = nEnd; E&w7GZNt  
nThreadID = id; nFCC St$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BOX2O.Pm  
} G.B2('  
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 /maJtX'  
public void run()
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{ 4at?(B+  
while(nStartPos < nEndPos && !bStop) DCa^ u'f  
{ -i|}m++  
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try{ y.k~Y0  
URL url = new URL(sURL); 8Fh)eha9f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^7*11%Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); >Tx?%nQ  
String sProperty = "bytes="+nStartPos+"-"; TX/Xt7#R:  
httpConnection.setRequestProperty("RANGE",sProperty); ,p
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Utility.log(sProperty); 'Is kWgc  
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InputStream input = httpConnection.getInputStream(); .{^5X)  
//logResponseHead(httpConnection); kZ:ZtE  
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byte[] b = new byte[1024]; wlvgg  
int nRead; Z{d^-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P+sW[:  
{ 3?yg\  
nStartPos += fileAccessI.write(b,0,nRead); @mBQ?;qlK  
//if(nThreadID == 1) n@i HFBb  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T-L||yE,h  
}
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Utility.log("Thread " + nThreadID + " is over!"); o|:b;\)b  
bDownOver = true; "sCRdx]_  
//nPos = fileAccessI.write (b,0,nRead); +\A,&;!SR  
} Qv-_ jZ  
catch(Exception e){e.printStackTrace ();} rlLMT6r.8  
} _VN?#J)o  
} 6 "sSoj  
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yyJf%{  
//打印回应的头信息 ]m<$}  
public void logResponseHead(HttpURLConnection con) I236RIq  
{  (ZizuHC  
for(int i=1;;i++) F>l] 9!P|m  
{ ?l )[7LR4  
String header=con.getHeaderFieldKey(i); Avc%2+  
if(header!=null) \\qZl)P_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 59A}}.@?m  
Utility.log(header+" : "+con.getHeaderField(header)); )akoa,#%6c  
else LL!Dx%JZ  
break; 7}>EJ  
} ki!0^t:9  
} t*u:hex  
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public void splitterStop() 4VSU8tK|N]  
{ Sm|6 %3  
bStop = true; VA5xp]  
} CC
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} 4HlQ&2O%#  
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/* `^&OF uee  
**FileAccess.java eauF~md,  
*//文件访问(定位，写) 0h_|t-9j  
package NetFox; Yq KCeg  
import java.io.*; %u'ukcL7  
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public class FileAccessI implements Serializable{ :I#V.  
&QgR*,5eo  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Rm( "=(  
RandomAccessFile oSavedFile; }7Q%6&IR  
long nPos; /8S>;5hvK@  
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public FileAccessI() throws IOException L8B!u9%  
{ 77Y/!~kd  
this("",0); V,njO{Q  
} 7.oM J  
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public FileAccessI(String sName,long nPos) throws IOException ?@86P|19  
{ ;Y, y4{H3  
oSavedFile = new RandomAccessFile(sName,"rw"); ~DwpoeYX  
this.nPos = nPos; e^voW"?%  
oSavedFile.seek(nPos); <5051UEu  
} 2+XAX:YD  
;V!D:5U  
@VEb{ w[H  
public synchronized int write(byte[] b,int nStart,int nLen) }K(TjZR  
{ 9*M,R,y  
int n = -1; @yYkti;4-  
try{ zb3tIRH  
oSavedFile.write(b,nStart,nLen); =s6 opL)  
n = nLen; 59u}W 0  
} l/5 hp.  
catch(IOException e) [/r(__.  
{ `a/`,N  
e.printStackTrace (); ^2rN>k,?  
} yG{TH0tq  
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return n; SXh-A1t  
} "tK=+f`NM  
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} m&3xJuKih  
~} ~4  
/;$[E  
/* OyIw>Wfv  
**SiteInfoBean.java "AqB$^S9t  
*/ tH4B:Bgj!  
package NetFox; #'`{Qv0,  
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HoAy_7-5  
public class SiteInfoBean { 2=}FBA,2  
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private String sSiteURL; //Site's URL yHaGkm  
private String sFilePath; //Saved File's Path #'}*dy/  
private String sFileName; //Saved File's Name :`sUt1Fw.  
private int nSplitter; //Count of Splited Downloading File \;Weizq5  
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public SiteInfoBean() (9)Q ' 'S  
{//nSplitter的缺省值为5 ]:n,RO6  
//default value of nSplitter is 5 ['D]>Ot68  
this("","","",5); <_+X 88  
} BA.uw_^4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) zQ PQ  
{ #-J>NWdt  
sSiteURL= sURL; fP1!)po  
sFilePath = sPath; e3\T)x&=  
sFileName = sName; !,PWb3S  
this.nSplitter = nSpiltter; j>kqz>3  
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i XN1I  
}  \=o-  
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public String getSSiteURL() vDvFL<`vmD  
{ nk:)j:fr  
return sSiteURL; hbn([+xY  
} \M-OC5fQv  
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public void setSSiteURL(String value) <VE@DBWyl~  
{ dRMx[7jVA  
sSiteURL = value; :Dp0?&_  
} F'Z,]b'st3  
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)
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public String getSFilePath() }m8q}~>tL  
{ uAk.@nfiEv  
return sFilePath; ?7A>+EY  
} aq-~B~c`g  
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public void setSFilePath(String value) a'T;x`b8U,  
{ dr"1s-D4IQ  
sFilePath = value; x1a:u  
} /wv0i3_e  
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public String getSFileName() nt<]d\o0  
{ d-%hjy3N  
return sFileName; EM_d8o)`B  
} 1;iUWU1@  
,%y/kS]  
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public void setSFileName(String value) /{2,zW  
{ OrW  
sFileName = value; u?EN  
}  :11 A  
r_d!ikOT(  
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public int getNSplitter() ^rz_f{c]-  
{ L},_.$I?  
return nSplitter; :'ptuY  
} >mkFV@`  
jWgX_//!  
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public void setNSplitter(int nCount) FTldR;}(  
{ YYS0`  
nSplitter = nCount; O0:q;<>z  
} |BYRe1l6l  
} iRBfx  
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/* kf9X$d6   
**Utility.java m[2gdJK  
*/ ig"L\ C"
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package NetFox; bK7J}8hH  
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public class Utility { H*6W q  
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public Utility() ~Gw*r\\+  
{ 3XKf!P  
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} !~Z"9(v'C  
,//S`j$S  
//线程睡眠 8EY:tzw  
public static void sleep(int nSecond) ^sZ,2,^  
{ vD4*&|8T#  
try{ 5R7DDJk  
Thread.sleep(nSecond); 0\$2X- c  
} 1x^GWtRp  
catch(Exception e) D'4\*4is  
{ H
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e.printStackTrace (); #E]59_  
} 4K74=r),i  
} *ui</+  
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//日志 vSh`&w^*  
public static void log(String sMsg) ?ubro0F:  
{ 5-M-X#(  
System.err.println(sMsg); '>" 4  
} ^@]3R QB  
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public static void log(int sMsg) Mihg:  
{ P;*(hY5&  
System.err.println(sMsg); :EyD+!LJ  
} E"0>yl)  
} >d6|^h'0  
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4+i
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/* {Ha57Wk8D  
**TestMethod.java M3AXe]<eC1  
*/ Pc9H0\+Xk  
package NetFox; zreU')a  
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public class TestMethod { 0$njMnB2l  
#;<Y[hR{P  
@|r{;'  
public TestMethod() W9)&!&<
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{ ///xx/weblogic60b2_win.exe 9FX-1,Jx  
try{ ~s{$WL&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); svSVG:48  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); f!"w5qC^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E_`=7i  
fileFetch.start(); @
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} E.f%H(b  
catch(Exception e){e.printStackTrace ();} Ep}s}Stlr}  
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%$mA03[MQ  
} ZB{EmB0W  
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public static void main(String[] args) <uJ@:oWG7  
{ |g~ZfnP_%  
new TestMethod(); \DzGQ{`~
m  
} yHGADH0B  
} Mfs?x a  
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