http断点续传简单实现（java)

/* 1a90S*M  
**SiteFileFetch.java V|.aud=7z  
*/ E `)p,{T  
package NetFox; ]Nvtiw 6  
import java.io.*; 0n,5"B  
import java.net.*; [j0I}+@4H  
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public class SiteFileFetch extends Thread { %1]2+_6  
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SiteInfoBean siteInfoBean = null; //文件信息Bean = sIR[V'(  
long[] nStartPos; //开始位置 9hT^Y,c0  
long[] nEndPos; //结束位置 y+?tUSPP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 I
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long nFileLength; //文件长度 9kP!O_  
boolean bFirst = true; //是否第一次取文件 7-ba-[t#A  
boolean bStop = false; //停止标志 G6eC.vU]j  
File tmpFile; //文件下载的临时信息 E!VAA=  
DataOutputStream output; //输出到文件的输出流 [JVI@1T  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） tb0XXEE  
public SiteFileFetch(SiteInfoBean bean) throws IOException @6$r|:]G-  
{ $#@4i4TN-  
siteInfoBean = bean; 9MLvHrB;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ),\>'{~5&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); AEnS_Q  
if(tmpFile.exists ()) Oyq<y~}  
{ ;.W0Aa  
bFirst = false; [`fq4Ky  
read_nPos(); gqD`1/  
} P+3G*M=}  
else }C7tlA8,7  
{ s80_e  
nStartPos = new long[bean.getNSplitter()]; /@RnCjc'  
nEndPos = new long[bean.getNSplitter()]; G-3.-  
} #K!Df%,<  
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} ].dTEzL9X  
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public void run() Hs=!.tZ,  
{ 7^iF,
N  
//获得文件长度 6ddkUPTF  
//分割文件 NTL#!  
//实例FileSplitterFetch m4Wn$Z  
//启动FileSplitterFetch线程 E}@8sY L  
//等待子线程返回 pN0c'COy^  
try{ : 1fik  
if(bFirst) faO8 &  
{ UWn}0:6t  
nFileLength = getFileSize(); mZ;yk(  
if(nFileLength == -1) cfeX(0  
{ }aNiO85  
System.err.println("File Length is not known!"); 38q@4U=aiw  
} DhZtiqL#_  
else if(nFileLength == -2) j|`{ 1`'  
{ 4nl>&A
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System.err.println("File is not access!"); z}bnw2d]  
} Xb^\{s?b  
else _f3A6ER`  
{ k)v[
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for(int i=0;i<nStartPos.length;i++) eF8`an5S  
{ 8nnkv,wa  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); M?cKt
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} jm-0]ugY&`  
for(int i=0;i<nEndPos.length-1;i++)
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{ D8?$Fn=  
nEndPos = nStartPos[i+1]; BRD'5 1]|  
} @>9
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nEndPos[nEndPos.length-1] = nFileLength; TLSy+x_gX  
} (FjgnsW  
} u\e#_*>  
==XP}w)m  
9)l_(*F  
//启动子线程 y9*H  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; k9Sqp:l,  
for(int i=0;i<nStartPos.length;i++) q6Q=Zo@  
{ }qD.Ek  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _yWH\5@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Y$ChMf  
nStartPos,nEndPos,i); R
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q?a"uei[  
fileSplitterFetch.start(); 3,vH:L4  
} :):Y6)giBD  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'o7PIhD"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); phc1AN=[E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", f0D Ch]  
nEndPos = " + nFileLength); @&Nvb.5nT  
// fileSplitterFetch[nPos.length-1].start(); KV5lpN PC  
4*+EUJ|  
xapkhIW2\  
//等待子线程结束 ]F@md(J  
//int count = 0; }a9C/t3  
//是否结束while循环 Nr[Rp  
boolean breakWhile = false; \OU+Kl<  
li%-9Jd  
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while(!bStop) MtYP3:  
{ ^X&9"x)4  
write_nPos(); "qj[[LQ  
Utility.sleep(500); lTB!yF.r|  
breakWhile = true; wFJK!9KA8  
,#E5/'c`  
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for(int i=0;i<nStartPos.length;i++) jO,<7FPs5  
{ aydal9M  
if(!fileSplitterFetch.bDownOver) r6$=|Yto  
{ KvD$`"L/CT  
breakWhile = false; c}QJ-I  
break; aqM_t  
} !n{c#HfG  
} UeICn@)\y  
if(breakWhile) $1?X%8V  
break; ~d8>#v=Q`  
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/J+)P<_A  
//count++; @}?D<O8#"#  
//if(count>4) =N{eiJ.(p  
// siteStop(); &tgvE6/V  
} OV/FQH;V  
)j6>b-H  
*h4m<\^U  
System.err.println("文件下载结束！"); Az-!LAu9 R  
} 3EZwF  
catch(Exception e){e.printStackTrace ();} =CVT8(N*  
} hX_p5a1t  
A pjqSz"  
Q$vr`yV#=6  
//获得文件长度 YW{V4yW  
public long getFileSize() ? g{,MP5  
{ >Y+KL  
int nFileLength = -1; D9C}Dys  
try{ Cv~hU%1T  
URL url = new URL(siteInfoBean.getSSiteURL()); Qf|}%}%fp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "?{yVu~9  
httpConnection.setRequestProperty("User-Agent","NetFox"); d8kwW!m+  
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int responseCode=httpConnection.getResponseCode(); 9Bk}g50$#  
if(responseCode>=400) be/1-=m  
{ n`}&,UA$4  
processErrorCode(responseCode); N 9&@,3  
return -2; //-2 represent access is error :b;1P@W<  
} CCY|FK  
k@aP&Z~  
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String sHeader; #5C3S3e=  
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for(int i=1;;i++) #(IMRdUf  
{ ~|9LWp_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #Q@6:bBzv  
//Utility.log(in.readLine()); XC1lo4|  
sHeader=httpConnection.getHeaderFieldKey(i); erP>P  
if(sHeader!=null)  y:OywIi(  
{ W{+0iAYnp  
if(sHeader.equals("Content-Length")) Ql@yN@V  
{ %9/)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sYA-FO3gh  
break; is?&%VY  
} _<a)\UR  
} j$|C/E5?  
else r65
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break; 3Gl]g/  
} =+h!JgY/L  
} rgzI  
catch(IOException e){e.printStackTrace ();} dO4#BDn"=  
catch(Exception e){e.printStackTrace ();} ]0i2]=J&,  
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Utility.log(nFileLength); +@uC:3jM  
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return nFileLength; p\_qHq\;j  
} GLQvAHC  
]GtR8w@w  
6J-
}&U  
//保存下载信息（文件指针位置） eH!|MHe  
private void write_nPos() $ XsQ e  
{ c;rp@_ULG?  
try{ U\8#Qvghf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); q7 oR9  
output.writeInt(nStartPos.length); [E~,>Q  
for(int i=0;i<nStartPos.length;i++) EjX'&"3.  
{ x0A%kp&w  
// output.writeLong(nPos); cNr][AzU@  
output.writeLong(fileSplitterFetch.nStartPos); <Ihed|  
output.writeLong(fileSplitterFetch.nEndPos); mjl!Nth:<  
} n{Qh8"  
output.close(); 3d'ikkXK  
} y [9}[NMZ  
catch(IOException e){e.printStackTrace ();} 06@0r  
catch(Exception e){e.printStackTrace ();} To8v#.i  
} }Q=se[((  
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//读取保存的下载信息（文件指针位置） Z^`=!n-V  
private void read_nPos() g} ~<!VpX  
{ ;k&k#>L!K  
try{ #Wm@&|U  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ROt0<^<  
int nCount = input.readInt(); EOnp!]Y  
nStartPos = new long[nCount]; ?> MoV5  
nEndPos = new long[nCount]; Y
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for(int i=0;i<nStartPos.length;i++) `?o1cf A  
{ l&sO?P[ /  
nStartPos = input.readLong(); Xf_tj:eO~  
nEndPos = input.readLong(); 5-5(`OZ{'  
} &]yJCzo]  
input.close(); Y5i`pY/}#?  
} Cb%.C;q  
catch(IOException e){e.printStackTrace ();} BdoC6H  
catch(Exception e){e.printStackTrace ();} fpK0MS]=b  
} "p~]m~g  
B mBzOk^  
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private void processErrorCode(int nErrorCode) h GA0F9.U  
{ &8_f'+i0  
System.err.println("Error Code : " + nErrorCode); 9 /Ai(  
} C|d!'"p  
!:5`im;i  
K?Xo3W%K  
//停止文件下载 0o=6A<#x  
public void siteStop() K]pKe"M  
{ y|+~>'^JR  
bStop = true; p]
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for(int i=0;i<nStartPos.length;i++) R#7+  
fileSplitterFetch.splitterStop(); &X]=Qpl  
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} n#^?X  
} 6KCCbg/  
//负责部分文件的抓取 :&1=8^BY  
**FileSplitterFetch.java nA_ zP4  
*/ %hQM
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package NetFox; kk/+Vx~  
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nhQ44qRgQ  
import java.io.*; `^&1
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import java.net.*; B
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! F;<xgw  

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public class FileSplitterFetch extends Thread { RdvPsv}D  
D#/%*|  
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String sURL; //File URL X6Nm!od'  
long nStartPos; //File Snippet Start Position 5<
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long nEndPos; //File Snippet End Position 43u PH1 )  
int nThreadID; //Thread's ID kHJDX;  
boolean bDownOver = false; //Downing is over PK2R
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boolean bStop = false; //Stop identical wKi}@|0[
@  
FileAccessI fileAccessI = null; //File Access interface }KD7 Y  
4l%?mvA^m  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Pi"~/MGP$  
{ A^4kYOe  
this.sURL = sURL; EBIa%,  
this.nStartPos = nStart; vNK`Y|u@  
this.nEndPos = nEnd; fNAo$O4cm  
nThreadID = id; 0[2BY]`Z.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w`.T/  
} X#p o|,Q  
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public void run() ! =\DC,-CB  
{ re ]Ste  
while(nStartPos < nEndPos && !bStop) _d\u!giy  
{ C"U[ b%  
;*wT,2;  
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try{ `bZ2x
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URL url = new URL(sURL); :tjgg]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 409x!d~it  
httpConnection.setRequestProperty("User-Agent","NetFox"); E~<(i':  
String sProperty = "bytes="+nStartPos+"-";  d-ag  
httpConnection.setRequestProperty("RANGE",sProperty); un$ Z7W/  
Utility.log(sProperty); +(=0CA0GE  
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InputStream input = httpConnection.getInputStream(); Q3NPwM  
//logResponseHead(httpConnection); wr3_Bf3]  
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f!M[awj%  
byte[] b = new byte[1024]; h V|v6 _  
int nRead; Z^'?
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &J lpA<^s;  
{ J8GXI:y  
nStartPos += fileAccessI.write(b,0,nRead); P7'oXtW{o  
//if(nThreadID == 1) KrdZEi vb  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 93E,  
} IdV,%d{  
 !fQJL   

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Utility.log("Thread " + nThreadID + " is over!"); zp7V\W; &  
bDownOver = true; Sc;iAi (  
//nPos = fileAccessI.write (b,0,nRead); 3~[`[4n^  
} 1a($8>  
catch(Exception e){e.printStackTrace ();} DEUd[  
} `G=ztL!gq  
} Ss@u,`pr  
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] ?DDCew  
//打印回应的头信息 Q(~3pt
 
public void logResponseHead(HttpURLConnection con) 3W7;f!  
{ krQl^~@  
for(int i=1;;i++) <mv7HKVg  
{ Je#!Wd  
String header=con.getHeaderFieldKey(i); #dva0%-1  
if(header!=null) /<3;0~#){  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |eHwp  
Utility.log(header+" : "+con.getHeaderField(header)); g9yaNelDh)  
else Veb+^&   
break; rao</jN.9  
} ?1GY%-  
} W]@gQ(Ef  
'GEBxNH:  
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public void splitterStop() Ujce |>Wn  
{ `3f_d}b  
bStop = true; ,{.zh&=4  
} U0NOU#  
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} v-P8WFjca  
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/* E S#rs="  
**FileAccess.java $x?NNS_ "J  
*//文件访问(定位，写)
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package NetFox; iBG`43;  
import java.io.*; 1 L+=|*:  
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public class FileAccessI implements Serializable{ bjPka{PBj  
K^"w]ii=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 NJn&>/vM  
RandomAccessFile oSavedFile; k
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long nPos; 7cIC&(h5  
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public FileAccessI() throws IOException ,/i_QgP  
{ k/df(cs  
this("",0); 1|o$X  
} T#\p%w9d  
(7IqY1W  
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public FileAccessI(String sName,long nPos) throws IOException q
^Z~IZ8IT  
{ +
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oSavedFile = new RandomAccessFile(sName,"rw"); -G8c5b[  
this.nPos = nPos; ,`;jvY~Ec  
oSavedFile.seek(nPos); ./#e1m?.  
} HR;/Br  
uA~YRKer  
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public synchronized int write(byte[] b,int nStart,int nLen) "kX`FaAhY  
{ sT)6nV  
int n = -1; ,VAp>x+O  
try{ . 3GnZR,L  
oSavedFile.write(b,nStart,nLen); Q(l
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n = nLen; BR;QY1  
} RXBb:f  
catch(IOException e) pJd0k"{  
{ 3@&bxYXm  
e.printStackTrace (); o>2e!7  
} c\M#5+1j  
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return n; IQT cYl  
} wuKl-:S;Vs  
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} [_h%F,_ A  
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/* w TlGJ$D0  
**SiteInfoBean.java *9J1$Wa  
*/ (B&h;U$HAH  
package NetFox; $'^&\U~?  
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public class SiteInfoBean { )%s +?  
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private String sSiteURL; //Site's URL cqEHYJ;B  
private String sFilePath; //Saved File's Path Xem 05%,  
private String sFileName; //Saved File's Name wy''tqg6  
private int nSplitter; //Count of Splited Downloading File `K w7"  
Y~az!8j;Z  
kBbl+1{H  
public SiteInfoBean() }&1Iyb  
{//nSplitter的缺省值为5 *wwhZe4V  
//default value of nSplitter is 5 yLW/ -%I#u  
this("","","",5); $&IpX M]  
} z5 Bi=~=#  
@F?=a*s"!  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;W0]66&  
{ +
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sSiteURL= sURL; H>?F8R_iq  
sFilePath = sPath; _S"f_W  
sFileName = sName; Y;,Hzmbs6w  
this.nSplitter = nSpiltter; l)Zs-V!M^\  
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{]^2R>0Q  
} "x&3Z@q7  
.B>B`q;B
 
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public String getSSiteURL() t^.'>RwW|  
{ YdI0E   
return sSiteURL; vBNZ<L\|a  
} OC_M4
{9/  
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public void setSSiteURL(String value) =OYQM<q  
{ W/r^ugDV  
sSiteURL = value; t[EfOQ  
} &!jq!u$(  
#.<V^  
6^;^rUlm  
public String getSFilePath() Pd~MiyO;K  
{ 2J<&rKCF  
return sFilePath; &x0C4Kh  
} f7J,&<<5w  
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public void setSFilePath(String value) : ,p||_G&  
{ bC~~5Cm  
sFilePath = value; Fc8E Y*  
} JDv-O&]  
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h  
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public String getSFileName()   \&a.}t  
{ dn,gZ"<  
return sFileName; $D'^t(  
} WA.AFt  
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public void setSFileName(String value) 
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{ $%PVJs  
sFileName = value; &[@\f^~  
} :.iyR  
S &JJIFftO  
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public int getNSplitter() gLQ #4H  
{ VXm[-  
return nSplitter; wqD5d   
} 7byCc_,
  
8~ #M{}  
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public void setNSplitter(int nCount) LK}-lZ` i  
{ Bux'hc  
nSplitter = nCount; j7 d:v7+_  
} J!h^egP  
} <y)E>Fl  
phP>3f.T  
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/* f vLC_'M  
**Utility.java +a|/l  
*/ #Qbl=o4  
package NetFox; '#Dg8/r!  
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PuX
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public class Utility { ,P6=~q3k  
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public Utility() `cr(wdvI  
{ /\=MBUN  
@Bs0Avj.  
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} 7=P^_LcU  
t`|,6qEG  
//线程睡眠 V U~Dk);Bv  
public static void sleep(int nSecond) $h28(K%  
{  "0&N}  
try{ (/h5zCc/v  
Thread.sleep(nSecond); 'v&}(  
} O~@fXMthh  
catch(Exception e) 8
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{ xh0xSqDM  
e.printStackTrace (); T_#, A0G  
} ,EEPh>cXc  
} $%2H6Eg0  
bJ3(ckhq  
//日志 N.j "S'(i  
public static void log(String sMsg) |(% u}V?  
{ Zzj0\?Ul  
System.err.println(sMsg); } /:\U p  
} Yrn"saVc,  
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public static void log(int sMsg) #^rU x.  
{ [-w@.^:]X  
System.err.println(sMsg); nr\q7  
} v{;7LXy0  
} RL}KAGK  
HDIk9WC^  
Z=+03  
/* NZXjE$<Vr  
**TestMethod.java Lz4ehWntO  
*/ Bw<
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package NetFox; ZR3nK0  
 7}B  
.36^[Jsz":  
public class TestMethod { &ak6zM  
y79qwM.  
c-CYdi@  
public TestMethod() KN[d!}W:  
{ ///xx/weblogic60b2_win.exe 6C-YyI#s#  
try{ !3}deY8;#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (P@Y36j>N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); or?%-)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X K>&$<5{  
fileFetch.start(); g]$ 4~"|.  
} ..KwTf  
catch(Exception e){e.printStackTrace ();} k#)
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} g+[kde;(^  
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public static void main(String[] args) 6yIvaY$KR  
{ n2ndjE$  
new TestMethod(); fCUT[d+H  
} [Ot,q/hBJ  
} 3]LN;s]ac  
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