http断点续传简单实现（java)

/* "=yz
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**SiteFileFetch.java yZ,S$tSR  
*/  jRhRw;  
package NetFox; "89L^I  
import java.io.*; ESnir6HoU  
import java.net.*; >w#&f
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public class SiteFileFetch extends Thread { duoM>B>8]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \omfWW
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long[] nStartPos; //开始位置 UD^
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long[] nEndPos; //结束位置 @*iT%p_L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [uFv_G{H  
long nFileLength; //文件长度 'W/AYF^5  
boolean bFirst = true; //是否第一次取文件 +{WZpP},v  
boolean bStop = false; //停止标志 jm,:jkr  
File tmpFile; //文件下载的临时信息 :
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DataOutputStream output; //输出到文件的输出流 0iVeM!bM  
}[]1`2qD  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &;%,Axc  
public SiteFileFetch(SiteInfoBean bean) throws IOException n\u3$nGL1`  
{ ~{q; -&  
siteInfoBean = bean; i7\MVI8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;TboS-Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 56H~MnX  
if(tmpFile.exists ()) oWBjPsQ  
{ 0r]-Ltvl?}  
bFirst = false; ?6 "B4%
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read_nPos(); na3lbwq  
} Ie4Xk  
else bDnT><eH  
{ Wo6C0Z3g}  
nStartPos = new long[bean.getNSplitter()]; +HoCG;C{  
nEndPos = new long[bean.getNSplitter()]; bM"d$tl$?'  
} =:m6ge@C&H  
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} DlQ*'PX7  
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public void run() _7,4C?  
{ ,{BF`5bn|  
//获得文件长度
CW?R7A/  
//分割文件 -"}nm!j /5  
//实例FileSplitterFetch 2cko GafG{  
//启动FileSplitterFetch线程 x{1S!A^  
//等待子线程返回 tW%!|T5/  
try{ M)CQ|P  
if(bFirst) (*Q8!"D^6  
{ a 9Kws[  
nFileLength = getFileSize(); ~>S? m;  
if(nFileLength == -1) OD).kP}s^  
{ EgTj   
System.err.println("File Length is not known!"); b;"Z`/h  
} wa
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else if(nFileLength == -2) Sb?HRoe_  
{ 'y|p)r"  
System.err.println("File is not access!"); AP0z~
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} X9o6} %Y  
else )u.%ycfeV  
{ %+L3Xk]m'  
for(int i=0;i<nStartPos.length;i++) :@^
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{ \8/$ZEom  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #f }OR
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} _o?[0E  
for(int i=0;i<nEndPos.length-1;i++) j
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{ h:4F
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nEndPos = nStartPos[i+1]; wPr!.:MF  
} 5N$O  
nEndPos[nEndPos.length-1] = nFileLength; 4td9=dNA+l  
} Nj+g
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} r~PVh?  
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0t -=*7w%  
//启动子线程 #* Iyvx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )J1xO^tE  
for(int i=0;i<nStartPos.length;i++) 0>U7]wZKc  
{ ShJBOaE; -  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J@o$V- KK
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), A<[BR*n  
nStartPos,nEndPos,i); +%)bd  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >44,Dp]  
fileSplitterFetch.start(); 8WLBq-]G  
} 3W55m@w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a+P^?N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M`,`2I A  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Pk)H(,  
nEndPos = " + nFileLength); 077wk  
// fileSplitterFetch[nPos.length-1].start(); YeV
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>?r8D48`  
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//等待子线程结束 0[7tJbN  
//int count = 0; !^qpV7./l  
//是否结束while循环 lnt}l  
boolean breakWhile = false; #BhcW"@  
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M6z$*?<  
while(!bStop) Imz1"+E~  
{ C ,#D4  
write_nPos(); sdXZsQw  
Utility.sleep(500); FXFyF*w2  
breakWhile = true; 1_5]3+r_U-  
b}Wm-]|+  
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for(int i=0;i<nStartPos.length;i++) q82yh&  
{ H1hADn  
if(!fileSplitterFetch.bDownOver) Z1R{'@Y0Z  
{ aa/_:V@$~  
breakWhile = false; ,W5!=\Gg(  
break; z;Dc#SZnO(  
} lBNB8c0e"{  
} '?qI_LP?  
if(breakWhile) i`7:^v;  
break; UUqA^yJ  
0;2ApYks  
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//count++; a5uBQ?  
//if(count>4) ]w~ECP(ap  
// siteStop(); [}Y_O*C !  
} 1NQU96  
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System.err.println("文件下载结束！"); X?n($z/{  
} pu Z0_1uN  
catch(Exception e){e.printStackTrace ();} :zsMkdU  
} `f\+aD'u  
,*g.?q@W2  
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//获得文件长度 dS;Ui]/J  
public long getFileSize() \>c1Z5H>  
{ TS@U0Ror  
int nFileLength = -1; iKAqM{(  
try{ F
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URL url = new URL(siteInfoBean.getSSiteURL()); PQ(/1v   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t^8|t(Lq  
httpConnection.setRequestProperty("User-Agent","NetFox"); "hLmwz|a  
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/9SNXjfbt  
int responseCode=httpConnection.getResponseCode(); 0"DS>:Ntk  
if(responseCode>=400) |!*abc\`(`  
{ mjJ/rx{kbw  
processErrorCode(responseCode); xOdLct  
return -2; //-2 represent access is error -\V;Gw8mD  
} Zxn>
]Z_  
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String sHeader; 5~=wia  
0oo*F  
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for(int i=1;;i++) R/kfbV-b  
{ YbP}d&L  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F7U$7(I2G  
//Utility.log(in.readLine()); 2 D!$x+|  
sHeader=httpConnection.getHeaderFieldKey(i); ky@DH(^>  
if(sHeader!=null) GW!%DT  
{ _QiGrC  
if(sHeader.equals("Content-Length")) BaOPtBYA:  
{ #An_RU6h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Lr<?eWdCwJ  
break; G[\3)@I  
} !sav~dB)  
} VpWpC&  
else tz_WxOQ0  
break; %e1`wMa  
} MTeCmFe0;  
} 4/E>k <MA  
catch(IOException e){e.printStackTrace ();} jn#Ok@tZ  
catch(Exception e){e.printStackTrace ();} A:,R.P>`C  
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onF?;>[  
Utility.log(nFileLength); QS2~}{v  
@rxfOc0J#  
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return nFileLength; 6Y/TqI[   
} lBfG#\rdW~  
9H,Ec,.  
0A.9<&Lod  
//保存下载信息（文件指针位置） l5,}yTUta  
private void write_nPos() ?Fj>7  
{ [C(>e0r  
try{ )
*_n/^m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +y|H#(wBP  
output.writeInt(nStartPos.length); cK6IyJx-  
for(int i=0;i<nStartPos.length;i++) 1iIag}?p  
{ Q)l~?Fx  
// output.writeLong(nPos); #GA6vJ4^s  
output.writeLong(fileSplitterFetch.nStartPos); Ar1X mHq  
output.writeLong(fileSplitterFetch.nEndPos); XOd  
} vAo|o*  
output.close(); @BS7Gyw  
} h}<Ie <  
catch(IOException e){e.printStackTrace ();} .DZ8kKY  
catch(Exception e){e.printStackTrace ();} y2NVx!?n  
} 7g
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0} Lx}2  
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//读取保存的下载信息（文件指针位置） R*z:+p}oHy  
private void read_nPos() zqAp7:  
{ ~Is-^k)y  
try{ s+E-M=d0e  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); h,)UB1  
int nCount = input.readInt(); n%}Vd `c  
nStartPos = new long[nCount]; _,5)  
nEndPos = new long[nCount]; Q^\f,E\S  
for(int i=0;i<nStartPos.length;i++) DF~{i{  
{ 3hbUus  
nStartPos = input.readLong(); 7P7d[KP<  
nEndPos = input.readLong();  TrmU  
} +hKH\]  
input.close(); Y#aHGZ$i  
} [wR x)F"  
catch(IOException e){e.printStackTrace ();} ;mLbgiqQ J  
catch(Exception e){e.printStackTrace ();} BSbi.@@tp  
} sH{4.tw  
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private void processErrorCode(int nErrorCode) O^yDb  
{ ?q+^U>wy&  
System.err.println("Error Code : " + nErrorCode); iH[ .u{h  
} ~q05xy8  
@I,:(<6  
cpg+-Zf%  
//停止文件下载 :OvTZ ?\  
public void siteStop() J|GEt@o3  
{ hhynB^o  
bStop = true; qGPIKu  
for(int i=0;i<nStartPos.length;i++) A~7q=
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fileSplitterFetch.splitterStop(); ;fnE"}  
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} FfR%@ V'  
} `L1lGlt  
//负责部分文件的抓取 M<"H1>q@  
**FileSplitterFetch.java 4x%R4tk  
*/ pswEIa  
package NetFox; 4+j:]poYG{  
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import java.io.*; #>/stU-  
import java.net.*; fPLi8`r  
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public class FileSplitterFetch extends Thread { rAZsVnk?  
%SSBXWP  
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String sURL; //File URL @+`">a8},  
long nStartPos; //File Snippet Start Position 4RXF.kJ3=  
long nEndPos; //File Snippet End Position 5? rR'0  
int nThreadID; //Thread's ID wX!>&Gc.  
boolean bDownOver = false; //Downing is over V0
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boolean bStop = false; //Stop identical A(<"oAe|  
FileAccessI fileAccessI = null; //File Access interface o}4J|@Hi|4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Sd0y=!Pj=  
{ v%6mH6V  
this.sURL = sURL; ahJu+y  
this.nStartPos = nStart; !W ,pjW%Y  
this.nEndPos = nEnd; |zaYIVE[  
nThreadID = id; M~/R1\'&j  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,\cO>y@  
} `aw5"ns^V  
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public void run() iB=v >8l%  
{ a6vls]?  
while(nStartPos < nEndPos && !bStop) uNcE_<  
{ lh?TEQ  
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try{ DKGZm<G>  
URL url = new URL(sURL); B1C"F-2d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c[xH:$G?Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9 yE   
String sProperty = "bytes="+nStartPos+"-"; #*|0WaC  
httpConnection.setRequestProperty("RANGE",sProperty); kj4t![o+  
Utility.log(sProperty);  @aC2]  
Z} 8
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InputStream input = httpConnection.getInputStream(); X+*"FKm S.  
//logResponseHead(httpConnection); ]1XJQW@gF  
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:$#";t|  
byte[] b = new byte[1024]; <hO|:LX  
int nRead; du:%{4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) # [0>wEq  
{ )Z2l*fV  
nStartPos += fileAccessI.write(b,0,nRead); ?l3PDorR  
//if(nThreadID == 1) #<\A[Po  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O\(0{qu  
} VZ:LK  
'{t&!M`
 
pd[?TyVK;  
Utility.log("Thread " + nThreadID + " is over!"); ;U^7]JO;  
bDownOver = true; V_SZp8  
//nPos = fileAccessI.write (b,0,nRead); A{!D7kwTz~  
} XA$Z7_gu3  
catch(Exception e){e.printStackTrace ();} <~[A  
} (RL5L=,u  
} -I'@
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//打印回应的头信息 /kAu&}  
public void logResponseHead(HttpURLConnection con) pV3o\bk!  
{ zdwr5k  
for(int i=1;;i++) M]+FTz  
{ %Q}T9%Mtj  
String header=con.getHeaderFieldKey(i); k_2W*2'S  
if(header!=null) Dt9[uyP&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); azj:Hru&t#  
Utility.log(header+" : "+con.getHeaderField(header)); jH1!'1s|  
else c&+p{hH+  
break; X\I"%6$  
} drJ<&1O  
} <V}^c/c
!  
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public void splitterStop() oM=Ltxv}  
{ +=5Dt7/|  
bStop = true; k0=$mmmPY  
} \&&jzU2  
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Kh!h_  
} tr]=q9  

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/* QT;mCD=O
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**FileAccess.java /A U& X  
*//文件访问(定位，写) $6ZO V/0  
package NetFox; 6S;-fj  
import java.io.*; hJ+;N  
^cE|o&Rm;  
9`/\|t|V  
public class FileAccessI implements Serializable{ ^<0azza/(  
m17H#!`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {%S>!RA  
RandomAccessFile oSavedFile; "g)@jqq:>  
long nPos; 2BU%4IG  
g,5r)FU`  

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public FileAccessI() throws IOException o;+J3\  
{ MLL4nkO,`  
this("",0); A=7  [^I2  
} %|l^oC+E  
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;NrN#<j(!  
public FileAccessI(String sName,long nPos) throws IOException MYzyg  
{ N5ityJIgQ  
oSavedFile = new RandomAccessFile(sName,"rw"); ,cR=W|6cQm  
this.nPos = nPos; 4uW}.7
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oSavedFile.seek(nPos); H0Q.; !^  
} Rw$>()}H8  
A9_)
}  
&ACM:&Ob  
public synchronized int write(byte[] b,int nStart,int nLen) SBnwlM"AN  
{
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int n = -1; `ySm
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try{ "y_A xOH  
oSavedFile.write(b,nStart,nLen); o2cZ  
n = nLen; `%lgT+~T  
} ~.;S>o[  
catch(IOException e) L:HJ:  
{ r-#23iT.~  
e.printStackTrace (); f)xHSF"  
} ORPQ1%tu  
^^[MDjNy@  
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return n; }MKm>N  
} %Lec\(-4L  
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} %4:tRF  
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/* \de824  
**SiteInfoBean.java JzA`*X[  
*/ xm@vx}O:  
package NetFox;  fL9R{=I%  
 '&/"_  
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public class SiteInfoBean { J1I"H<}-6  
@D!KFJ  
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private String sSiteURL; //Site's URL Ol4)*/oZ  
private String sFilePath; //Saved File's Path >;S/$  
private String sFileName; //Saved File's Name zbt>5S_  
private int nSplitter; //Count of Splited Downloading File n>F1G MX  
R v61*F4  
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public SiteInfoBean() ;m{*iKL6{  
{//nSplitter的缺省值为5 yM%,*VZ  
//default value of nSplitter is 5 F&}>2QiL  
this("","","",5); uJ<sa;  
} YKwej@9,  
J]8nbl  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r40#-A$  
{ \S(:O8_"68  
sSiteURL= sURL; HFD5*Z~M  
sFilePath = sPath; k> I;mEV  
sFileName = sName; ' bio:1  
this.nSplitter = nSpiltter; \/C-e  
@`<vd@  
Ea@N:t?(8=  
} KDP7u  
[\NyBc  
/esSM~*H  
public String getSSiteURL() pEIc?i*  
{ >jjuWO3T  
return sSiteURL; @DYxxM-  
} @&;y0N1xo  
k~WX6rEJ  
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public void setSSiteURL(String value) "(/ 1]EH`  
{ [
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sSiteURL = value; RG=!,#X  
} W/U&w.$  
V.PbAN  

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public String getSFilePath() T$/6qZew  
{ ~
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return sFilePath; O@jW&-;  
} -[?q?w!?  
,o-BJ 069  
H"W%+{AR  
public void setSFilePath(String value) $F
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{ U@v=q9'W  
sFilePath = value; y?W8FL  
} d_BO&k<+I  
rt] @Z`w  
[nBlHI;&  
public String getSFileName() mT\!LpX  
{ TCJH^gDt  
return sFileName; E<;C@B  
} gc@,lNmi  
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public void setSFileName(String value) P`wp`HI  
{ w^09|k  
sFileName = value; WZaOw w  
} GkjTE2I3  
-p =b5L  
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public int getNSplitter() 4-efnB  
{ NZ`W`#{  
return nSplitter; Z++JmD1J  
} /)?]
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4`uI)N(}*  
public void setNSplitter(int nCount) |Euf:yWY  
{ M
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nSplitter = nCount; eS9/-Y  
} HErTFY+vC  
} 2bU3*m^M  
%^}3:0G  
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/* pulE6T7x  
**Utility.java CZg$I&x  
*/ h0`@yo  
package NetFox; uZ*;
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public class Utility { rWI6L3,i+  
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public Utility() OL&ku &J_  
{ L2Uk/E  
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} zZDa71>  
4'bup h1(  
//线程睡眠
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public static void sleep(int nSecond) DOiL3i"H  
{ "Q;n-fqf  
try{ N8;/Zd;^  
Thread.sleep(nSecond); 75}BI&t3k  
} Yd:8iJA  
catch(Exception e) fLl
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{ ai[st+1  
e.printStackTrace (); WP7*Q:5  
} };!S2+  
} GMRw+z4  
k8w }2Vw  
//日志 ^.
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public static void log(String sMsg) <hgt{b4  
{ iqURlI);P  
System.err.println(sMsg); ?)k;.<6  
} 0m_c43+^  
I:[^><?E  
)x
Ik
#>)  
public static void log(int sMsg) HkFoyy  
{ !Z2?dhS  
System.err.println(sMsg); :Zl@4}  
} `qp[x%7^  
} sEq_K#n{  
*j RNpB{)z  
DE:FWD<}  
/* Qc-jOl  
**TestMethod.java !lp*0h(7  
*/ Y##ftQ  
package NetFox; Oe=7
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rI)op1K  
lO>w|=<  
public class TestMethod { -kT *gIJ}  
j-@3jFu  
fEF1&&8^  
public TestMethod() B uV@w-|  
{ ///xx/weblogic60b2_win.exe ` WIv|S  
try{ }8Tr M0q8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <rV3(qb#]J  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3G|n`dj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); GV'Y'  
fileFetch.start(); <eKF  
} F Cg{!h  
catch(Exception e){e.printStackTrace ();} 9mfqr$3  
E'zLgU)r`  
rkh+$*t@i7  
} :hB/|H*=  
~#+ Hhc(  
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public static void main(String[] args) hDI_qZ  
{ 0@[]l{N  
new TestMethod(); oA`'~~!  
} S*<+vIo  
} 7<
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