http断点续传简单实现（java)

/* .^%!X!r  
**SiteFileFetch.java k5%:L2FO  
*/ M!e$h?vB  
package NetFox; 2Xt$KF,?  
import java.io.*; ;ESuj'*t  
import java.net.*; 4x'N#m{p  
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public class SiteFileFetch extends Thread { e(NpX_8  
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SiteInfoBean siteInfoBean = null; //文件信息Bean F
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long[] nStartPos; //开始位置 .Y"H{|]Mnh  
long[] nEndPos; //结束位置 ,%FBELqOW  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P,ox))+6  
long nFileLength; //文件长度 C)r!;u)AZH  
boolean bFirst = true; //是否第一次取文件 D/$$"AT  
boolean bStop = false; //停止标志 f.4m6"1  
File tmpFile; //文件下载的临时信息 HJn  
DataOutputStream output; //输出到文件的输出流 >%~%O`+  
*Hnk,?kPq  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） FYe(SV(9  
public SiteFileFetch(SiteInfoBean bean) throws IOException k>8,/ AZd  
{ Q]q`+
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siteInfoBean = bean; +H7lkbW
  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _p~lL<q-K[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;&N;6V"}  
if(tmpFile.exists ()) }BpCa6SAs  
{ lUR7zrwJ]o  
bFirst = false; qDQ$Zq[  
read_nPos(); ?>_[hZ  
} WzC_M>_  
else 0pSqk/  
{ |G5Me  
nStartPos = new long[bean.getNSplitter()]; ].j;d2xT\  
nEndPos = new long[bean.getNSplitter()]; m&H@f:  
} #sOkD  
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} )rTV}Hk  
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public void run() Wq+
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{ /GK1}h  
//获得文件长度 yJ(p-3O5  
//分割文件 MmjeFv  
//实例FileSplitterFetch RE72%w(oM  
//启动FileSplitterFetch线程 .."=  
//等待子线程返回 Wn(pz)+Y  
try{ 4&Q.6HkL  
if(bFirst) )>]~Y  
{ Wb_'X |"u  
nFileLength = getFileSize(); /5ngPHy&  
if(nFileLength == -1) 36<PI'l#~  
{ C>d_a;pX  
System.err.println("File Length is not known!"); ~v2E<S3  
} +w ;2kw  
else if(nFileLength == -2) A{5^A)$  
{ *20$u% z2  
System.err.println("File is not access!"); `Ns$HV  
} ZYy,gu<  
else J!$q"0G'WT  
{ ,~@Nhd~k  
for(int i=0;i<nStartPos.length;i++) 5$,dpLbL  
{ hcvWf\4'#q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >i>%
@  
} jXBAo  
for(int i=0;i<nEndPos.length-1;i++) r>=)Y32Q  
{ \;z*j|;B  
nEndPos = nStartPos[i+1]; { XN"L3A  
} >AT{\W!N  
nEndPos[nEndPos.length-1] = nFileLength; Fxu'(xa  
} A8?uCkG  
} &*wN@e(c  
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//启动子线程 q;dg,Om  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Pd99vq/  
for(int i=0;i<nStartPos.length;i++) w&eX)!  
{ vjy59m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kxJ! #%w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), d]JiJgfa%  
nStartPos,nEndPos,i); %1uY  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hrpql_9.  
fileSplitterFetch.start(); #
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} 2qY`*Y.2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,\y)k}0lH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qRXb9c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]-Z="YPY  
nEndPos = " + nFileLength); _;] 3w  
// fileSplitterFetch[nPos.length-1].start(); f?_UT}n  
[ 7W@/qqv  
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//等待子线程结束 ""GeO%J8  
//int count = 0; fdIO'L_  
//是否结束while循环 > .L\>  
boolean breakWhile = false; 1 m)WM,L  
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while(!bStop) UN7>c0B  
{ "r6DZi(^K  
write_nPos(); }B=`nbgIG7  
Utility.sleep(500); orB8q((  
breakWhile = true; ;(cqaB  
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for(int i=0;i<nStartPos.length;i++) |[ymNG  
{ *_ 2db  
if(!fileSplitterFetch.bDownOver) -6(u09mb_  
{ )z'LXy8  
breakWhile = false; YQb43Sh`  
break; t(-`==.R  
} _lrCf  
} >wiW(Ki}  
if(breakWhile) A %iZ_h^  
break; $F|3VQ~  
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//count++; c2aX_ "  
//if(count>4) ZXP9{Hh  
// siteStop(); KTV~g@Jf  
} 39jnoT  
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}%K)R5C  
System.err.println("文件下载结束！"); =-XI)JV#  
} 0{0|M8  
catch(Exception e){e.printStackTrace ();}  jpcbW  
} YK[PC]w  
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7B@[`>5?%L  
//获得文件长度 h rL_. 4  
public long getFileSize() 0_d,sC?V  
{ )/BI
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int nFileLength = -1; {\!_S+}{  
try{ 3urL*Fw,  
URL url = new URL(siteInfoBean.getSSiteURL()); biTET|U`$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BU-m\Kf)  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^oNk}:>  
0/7y&-/(  
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int responseCode=httpConnection.getResponseCode(); OR4ZjogzY  
if(responseCode>=400) Q{hXP*5  
{ 1bW[RK;GE  
processErrorCode(responseCode); \`:X37n)0q  
return -2; //-2 represent access is error 2&st/y(hs  
} %#!pAUP\&  
%d..L-`]ET  
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String sHeader; [D[&aA  
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for(int i=1;;i++) }!tJ
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{ CRK%%;=
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A#:5b5R  
//Utility.log(in.readLine()); |P{K\;-  
sHeader=httpConnection.getHeaderFieldKey(i); A^/$|@  
if(sHeader!=null) 86[/NTD<-  
{ ,2H@xji [  
if(sHeader.equals("Content-Length")) :JBvCyj4PE  
{ Qqt<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %nU8 Ca  
break; 9.F+)y@  
} F$l]#G.@A  
} K!|%mI8gk  
else wB(A['k  
break; $O}:*.{(W  
} cR0+`&  
} K OZHz`1!  
catch(IOException e){e.printStackTrace ();} {fi:]|<1h  
catch(Exception e){e.printStackTrace ();} W'f{u&<  
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Utility.log(nFileLength); A"wor\(  
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return nFileLength; }Wxu=b  
} dA;f`Bi;Q  
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//保存下载信息（文件指针位置） *],]E;  
private void write_nPos() RS'%;B-)  
{ &|t*9D  
try{ Ol8ma`}Nq3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j5lSu~  
output.writeInt(nStartPos.length); m791w8Vr  
for(int i=0;i<nStartPos.length;i++) 9UD~$_<\  
{ SKx&t-  
// output.writeLong(nPos); _7?LINF9  
output.writeLong(fileSplitterFetch.nStartPos); /UGH7srx  
output.writeLong(fileSplitterFetch.nEndPos); Pb05>J3N  
} &"vh=Z-  
output.close(); "Dbjp5_  
} [C@0&[[  
catch(IOException e){e.printStackTrace ();} Mz}yf5{f  
catch(Exception e){e.printStackTrace ();} -5 -X[`cF  
} joa|5v'  
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4  
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//读取保存的下载信息（文件指针位置） %T3
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private void read_nPos() AplXl=  
{ vh8{*9+  
try{ :G
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mz\d>0F U.  
int nCount = input.readInt(); _KSYt32N  
nStartPos = new long[nCount]; N :E7rtT,M  
nEndPos = new long[nCount]; &r\pQ};  
for(int i=0;i<nStartPos.length;i++) VH3j
 
{ `@MY}/ o.  
nStartPos = input.readLong(); n GE3O#fv  
nEndPos = input.readLong(); ht8%A 1|  
} 8 Zy`Z   
input.close(); b<UZDyN~  
} K*Tj;
  
catch(IOException e){e.printStackTrace ();} `>^2MHF3LT  
catch(Exception e){e.printStackTrace ();} X9^a:
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} W(N@`^  
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private void processErrorCode(int nErrorCode) x%kS:!  
{ SWujj,-[  
System.err.println("Error Code : " + nErrorCode); q.L0rY!  
} #S+GI!  
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/p
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//停止文件下载 0m?v@K' l  
public void siteStop() SOo/~giz|  
{ C!N&uNp@s  
bStop = true; f]F]wg\_f  
for(int i=0;i<nStartPos.length;i++) m S[Vl6  
fileSplitterFetch.splitterStop(); _aOisN{  
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} 7T \}nX1  
} CrHH Ob  
//负责部分文件的抓取 a%Ky;ys  
**FileSplitterFetch.java = E'\  
*/ SJhcmx+  
package NetFox; FilHpnQCt  
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import java.io.*; aagN-/mgm  
import java.net.*; Cs$wgm*  
=VkbymIZ4y  
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public class FileSplitterFetch extends Thread { gf6<`+
/  
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String sURL; //File URL mq@2zE`.(  
long nStartPos; //File Snippet Start Position @D%H-X  
long nEndPos; //File Snippet End Position <\]o#w*:  
int nThreadID; //Thread's ID xcO Si>  
boolean bDownOver = false; //Downing is over (JS1}T  
boolean bStop = false; //Stop identical X)iQ){21V  
FileAccessI fileAccessI = null; //File Access interface *7<5 G{  
b;#Z/phix  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `"J=\3->  
{ DZGM4|@<7Y  
this.sURL = sURL; -E1b5i;f  
this.nStartPos = nStart; O)|{B>2r  
this.nEndPos = nEnd; O:'UsI1Y  
nThreadID = id; j`1%a]Bwc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 kmjSSh/t  
} &i*/}OZz  
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public void run() 9(k5Irv"'h  
{ ]8*#%^  
while(nStartPos < nEndPos && !bStop) XiE  
{ d0YN:lJc  
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try{ } y@pAeS,  
URL url = new URL(sURL); 8"R;axeD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \nM$qr'`B  
httpConnection.setRequestProperty("User-Agent","NetFox");  6jFc'  
String sProperty = "bytes="+nStartPos+"-"; C*kGB(H7  
httpConnection.setRequestProperty("RANGE",sProperty); o9+"6V|.  
Utility.log(sProperty); 4bD^Kc4\  
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InputStream input = httpConnection.getInputStream(); ?qwTOi  
//logResponseHead(httpConnection); cA
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byte[] b = new byte[1024]; )`?Es8uW  
int nRead; +$M%"=tk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qQC<oR  
{ E,,)?^g  
nStartPos += fileAccessI.write(b,0,nRead); tW;?4}JR  
//if(nThreadID == 1) kxU<?0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 86!"b  
} ;pu68N(B  
rnWU[U8
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Utility.log("Thread " + nThreadID + " is over!"); -.=q6N4  
bDownOver = true; "2HSb5b"`  
//nPos = fileAccessI.write (b,0,nRead); jO\29(_  
}  ?CKINN  
catch(Exception e){e.printStackTrace ();} *'=JT#  
} a=bP   
} ~`M>&E@Y_/  
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//打印回应的头信息 6#P\DT  
public void logResponseHead(HttpURLConnection con) jH26-b<  
{ $ )ps~  
for(int i=1;;i++) 
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{ %''z~LzJ8  
String header=con.getHeaderFieldKey(i); rug^_d=B  
if(header!=null) K8CjZpzq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `WvNN>R  
Utility.log(header+" : "+con.getHeaderField(header)); K2PV^Y  
else Q7oJ4rIP  
break; <I .p{Z  
} rJi;"xF8  
} 2*:lFvwP  
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public void splitterStop() (as'(+B  
{ ;4<CnC**  
bStop = true; nHxos`Qx  
} $c4Q6w  
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} 5qo^SiB.  
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/* $#ks`$vM  
**FileAccess.java +tFm DDx=  
*//文件访问(定位，写) 1.WdxMpW9  
package NetFox; c$aTl9e  
import java.io.*; (3YqM7cqt  
F#S^Q`  
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public class FileAccessI implements Serializable{ 1;E[Ml  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 zh7#[#>t  
RandomAccessFile oSavedFile; f&=y\uP]  
long nPos; Pk444_"=  
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public FileAccessI() throws IOException o"D`_ER  
{ Rz% Px:M  
this("",0); }m NP[L  
}  e;8>/G  
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public FileAccessI(String sName,long nPos) throws IOException ZM"J5}h  
{ z#*M}RR  
oSavedFile = new RandomAccessFile(sName,"rw"); >xu}eWSz  
this.nPos = nPos; QW :-q(s  
oSavedFile.seek(nPos); ^L}fj$  
} "(j.:jayd  
<]I[|4J 7  
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public synchronized int write(byte[] b,int nStart,int nLen) U1(<1eTyu  
{ \.p{~Hv  
int n = -1; | ZBv;BW  
try{ T)Z2=5V  
oSavedFile.write(b,nStart,nLen); 9u<4Q_I`  
n = nLen; |aef$f5  
} XE);oL2xP  
catch(IOException e) ^yDCX  
{ >QRpRHtb  
e.printStackTrace (); 5_";EED  
}  TA;  
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return n; n,sl|hv2U  
} UP=0>jjbn:  
@2Xw17[f35  
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} Z\8TpwD2  
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~6!{\un   
/* F-Mf~+=Dn  
**SiteInfoBean.java m}w~ d /  
*/ )f]E<*k'E  
package NetFox; i/QE)"B"q  
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public class SiteInfoBean { }8cL+JJU  
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private String sSiteURL; //Site's URL xvP<~N-  
private String sFilePath; //Saved File's Path yiyyw,iy  
private String sFileName; //Saved File's Name WP&P#ju&  
private int nSplitter; //Count of Splited Downloading File \y?Vou/  
/NFv?~</k  
W 0^.Dx  
public SiteInfoBean() A `\2]t$z  
{//nSplitter的缺省值为5 nokk!v/  
//default value of nSplitter is 5 v>zeK  
this("","","",5); $h1`-=\7  
} LY}%|w  
vgRjd1k.\y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }.O,P'k  
{ [eL?O;@BD  
sSiteURL= sURL; 0eq="|n^|  
sFilePath = sPath; O~yPe.  
sFileName = sName; +=#sam*i  
this.nSplitter = nSpiltter; KJc fbZ~  
9?<WRM3a>  
HFYN(nz}[  
} qPsf
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3  
>0kn&pe7#T  
public String getSSiteURL() hX4&B  
{ `Q?rQ3A}  
return sSiteURL; 2Jo'!|]  
} M@@l>"g@  
X%Jq9_  
:-HVK^$%  
public void setSSiteURL(String value) i-Ck:-J  
{ 4Z>KrFO  
sSiteURL = value; --E_s/  
} 1~\YJEsb}d  
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public String getSFilePath() 3]DUUXg$  
{ Wr"
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return sFilePath; fsqK(io28  
} b|| c^f  
bmN'{09@  
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public void setSFilePath(String value) l;
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{ :'RmT
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sFilePath = value; EGWm0 F_  
} nDx}6}5)  
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public String getSFileName() V'(yrz!  
{ d*80eB9P  
return sFileName; \zioIfHm  
} >Qg`Us
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4'JuK{/ A7  
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public void setSFileName(String value) [5>f{L!<T<  
{ `tKrTq>  
sFileName = value; @R%n &  
} vd`;(4i#X  
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public int getNSplitter() Gkci_A*  
{ sd|5oz)  
return nSplitter; kj_o I5<'  
} =`fJ  
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public void setNSplitter(int nCount) 5etbJk  
{ #(6
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nSplitter = nCount; e=$p(  
} x=
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} ]hY'A>4Uq  
?;NC(Z,  
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/* G3O`r8oZcJ  
**Utility.java Gs^hqT;h  
*/ Wj0=cIb  
package NetFox; %Wy$m?gD  
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"%$jl0i_c  
public class Utility { B3 fKb#T  
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=+
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public Utility() D"kss5>w  
{ v eP)ElX  
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} KLVkPix;$  
R5PXX&Q  
//线程睡眠 NN(ZH73  
public static void sleep(int nSecond) t5
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{ n.+%eYM<  
try{ z8v]Kt&  
Thread.sleep(nSecond); GZY8%.1{"a  
} 9z>I&vcX  
catch(Exception e) :&*Y Io  
{ *d%"/l^0  
e.printStackTrace (); @'UbTB!  
} wuRB[KLe  
} -E, d)O`;$  
M\4pTcz{  
//日志 SMX70T!'9  
public static void log(String sMsg) 3$x[{\ {  
{ N|t!G^rP  
System.err.println(sMsg); G i1Jl"  
} dw'&Av' |E  
2d1Z;@x  
5]_m\zn=  
public static void log(int sMsg) xz!b@5DR'%  
{ S0-f_,(  
System.err.println(sMsg); >uHU3<2&  
} RsTz3]`yv  
} 9g%1^$R  
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Udj
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/* fC6zDTis8A  
**TestMethod.java z?T;2/_7  
*/ 6T*MKu  
package NetFox; ^y" #2Ov  
&Pk #v  
|qUi9#NUo  
public class TestMethod { 25e*W>SLw  
OH.lAF4E(  
'
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public TestMethod() 7 'T3Wc  
{ ///xx/weblogic60b2_win.exe )Z4i

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try{ c*>8VW>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \gz(C`4{j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ..FEyf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5UWj#|t  
fileFetch.start(); W4MU^``   
} rV6&:\  
catch(Exception e){e.printStackTrace ();} :#_Ne?\a@  
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c5 ^CWk K  
} ,|5|aVfh  
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public static void main(String[] args) f\p#3IwwH  
{ }%^N9AA8  
new TestMethod(); dWc'RwL  
} oRDqN]  
} CjFnE  
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