http断点续传简单实现（java)

/* oR+-+-??$  
**SiteFileFetch.java CF y}r(q  
*/ $KV&\Q3\0  
package NetFox; <x%M3BTx  
import java.io.*; Dkw%`(Oh/,  
import java.net.*; O[~x_xeW  
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public class SiteFileFetch extends Thread { uE_c4Hp  
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SiteInfoBean siteInfoBean = null; //文件信息Bean @ $cUNvI  
long[] nStartPos; //开始位置 AH7L.L+$M  
long[] nEndPos; //结束位置 .;/L2Jv  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 db=$zIB[:  
long nFileLength; //文件长度 qG8s;_G  
boolean bFirst = true; //是否第一次取文件 r >{G`de4  
boolean bStop = false; //停止标志 ,1n >U?5  
File tmpFile; //文件下载的临时信息 !jX4`/n2  
DataOutputStream output; //输出到文件的输出流 2f,B$-#  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4k}e28  
public SiteFileFetch(SiteInfoBean bean) throws IOException MlO-+}`_+  
{ 4|J[Jdj  
siteInfoBean = bean; @B1{r|-<^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SDJH;c0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Pd=,$UQp  
if(tmpFile.exists ()) s}x>J8hK  
{ l4'~}nn(Y  
bFirst = false; >}+Q:iNQ)2  
read_nPos(); %(m])  
} Id8wS!W`7  
else (ClhbfzD  
{ V}8$p8#<@  
nStartPos = new long[bean.getNSplitter()]; #m. AN  
nEndPos = new long[bean.getNSplitter()]; eBB:~,C^q.  
} :1fagaPg  
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} }Ag|gF!_  
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public void run() </oY4$l'  
{ /9ZcM]X B  
//获得文件长度 B:oF;~d/
,  
//分割文件 I@7/jUO  
//实例FileSplitterFetch Z_z#QX>=D  
//启动FileSplitterFetch线程 :Z`4j  
//等待子线程返回 GKtS6$1d#  
try{ x/TGp?\g  
if(bFirst) z MdC  
{ )na&"b
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nFileLength = getFileSize(); gy_$#e  
if(nFileLength == -1) ))#'4  
{ TYS\95<  
System.err.println("File Length is not known!"); M=!i>(yG  
} /lD?VE  
else if(nFileLength == -2) [$\>~nj=  
{ :iCM=k  
System.err.println("File is not access!"); T-L5zu  
} d+2daKi  
else !e8i/!}^S  
{ ;b~~s.+  
for(int i=0;i<nStartPos.length;i++) \P?ToTTV  
{ L/r{xS  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); vE\lp8j+  
} BA+_C]%ZJ  
for(int i=0;i<nEndPos.length-1;i++) L'kq>1QWf  
{ r2eQ{u{nX  
nEndPos = nStartPos[i+1]; hY8#b)l~lu  
}  WR.x&m
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nEndPos[nEndPos.length-1] = nFileLength; bkQ3c-C<  
} u}jrfKdE  
} n.$(}A  
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8OAg~mQ15(  
//启动子线程 H~9=&p[Q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Z!\@%`0$  
for(int i=0;i<nStartPos.length;i++) xfHyC'?  
{ `F1dyf!p<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oh\,O
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), YdOUv|tZC  
nStartPos,nEndPos,i); P#tvm,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tHI*,  
fileSplitterFetch.start(); "DckwtG:%  
} =HE m)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %?tq;~|]Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z;<ep@gy~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", TbNGgjT  
nEndPos = " + nFileLength); [&VxaJ("3  
// fileSplitterFetch[nPos.length-1].start(); lizTRVBE  
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//等待子线程结束 DX@}!6|T  
//int count = 0; FBYODw  
//是否结束while循环 B=zMYi  
boolean breakWhile = false; Q=+8/b  
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while(!bStop) -V=arm\#z  
{ <5ZJ]W  
write_nPos(); c4|so=  
Utility.sleep(500); :XS"#^aJ  
breakWhile = true; Dd/}Ya(Gi  
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for(int i=0;i<nStartPos.length;i++) -CU,z|g+  
{ 5-'vB  
if(!fileSplitterFetch.bDownOver) <o@)SD~K  
{ 2V$9ei6  
breakWhile = false; F0;1zw  
break; `Cj,HI_/*  
} `^%GN8d}nm  
} "6V_/u5M;=  
if(breakWhile) hEOJb @:R  
break; WEC-<fN|Y\  
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//count++; NgxO&Zp  
//if(count>4) I7Zq}Pxa  
// siteStop(); kPJ~X0Fr{t  
} ?UK:sF|(O  
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System.err.println("文件下载结束！"); OK\]*r  
} M(S{1|,V  
catch(Exception e){e.printStackTrace ();} # U`&jBU  
} }#YQg0(  
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//获得文件长度 LW?2}`+  
public long getFileSize() /nM*ljfB\  
{ UCF[oO>v  
int nFileLength = -1; '%Dg{ zL  
try{ ZOHRUm  
URL url = new URL(siteInfoBean.getSSiteURL()); ^'Zh;WjI7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SRk7gfP*q  
httpConnection.setRequestProperty("User-Agent","NetFox"); r %xB8e9  
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int responseCode=httpConnection.getResponseCode(); Na;t#,  
if(responseCode>=400) N[{]iQ  
{ 4H9xO[iM  
processErrorCode(responseCode); 3mA/Nu_  
return -2; //-2 represent access is error Ib(,P3  
} -9Xw]I#QR  
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String sHeader; ~$ WQ"~z  
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for(int i=1;;i++) bgXc_>T6_y  
{ 2^ kn5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s.ey!ew  
//Utility.log(in.readLine()); ^ N_`^m  
sHeader=httpConnection.getHeaderFieldKey(i); ZArf;&8  
if(sHeader!=null) n(# c`t*  
{ F~P/*FFK  
if(sHeader.equals("Content-Length")) c$.T<r)Z  
{ P#9-bYNU  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); JgZdS-~  
break; "U{mMd!9L  
} qZc)Sa.S  
} Ot"(uW4$[  
else .=aMjrME  
break; @%7
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} X)FQ%(H<  
} g&8.A(  
catch(IOException e){e.printStackTrace ();} W.sD2f  
catch(Exception e){e.printStackTrace ();} ,|>nF;.Y  
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Utility.log(nFileLength); (BhL/A 4  
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return nFileLength; xKisL=l6Y  
} dR?5$V(  
s={X-H< 2  
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//保存下载信息（文件指针位置） JG1
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private void write_nPos() _4A&%>   
{ ]n/jJ_[  
try{ m';|}z'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s UvKA0  
output.writeInt(nStartPos.length); ,7/\&X<`B  
for(int i=0;i<nStartPos.length;i++) 4v i B=>  
{ ;+!xZOmm  
// output.writeLong(nPos); sd7Y6?_C  
output.writeLong(fileSplitterFetch.nStartPos); i@%L_[MtA  
output.writeLong(fileSplitterFetch.nEndPos); $jDD0
<F.#  
} ;vZ*,q6  
output.close(); ug>]U ~0  
} E,Dlaq  
catch(IOException e){e.printStackTrace ();} )z|_*||WU^  
catch(Exception e){e.printStackTrace ();} J\9jsx!WQ  
} .|tQ=l@I  
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//读取保存的下载信息（文件指针位置） 8cequAD  
private void read_nPos() g8B&u u #  
{ P/HHWiD`D  
try{ ],WwqD=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); k0R,!F  
int nCount = input.readInt(); [)B@  
nStartPos = new long[nCount]; puk4D  
nEndPos = new long[nCount]; _LLW{^V  
for(int i=0;i<nStartPos.length;i++) *YMXiYJR  
{ 6NP`P jR  
nStartPos = input.readLong(); Gf!t< =T   
nEndPos = input.readLong(); %Gnd"SGs  
} nT(!HD
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input.close(); d;IJ0xB+by  
} F12S(5Z0%  
catch(IOException e){e.printStackTrace ();} 6i55Ja  
catch(Exception e){e.printStackTrace ();} 4h[2C6 \+`  
} WIhIEU7/  
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3
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private void processErrorCode(int nErrorCode) =2Pz$q*ub  
{ MX%|hIOpr  
System.err.println("Error Code : " + nErrorCode); }"!6Xm  
} ,<IL*=a  
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//停止文件下载 99=[>Ck)G  
public void siteStop() GA}hp%  
{ kjQIagw  
bStop = true; })Ix.!p  
for(int i=0;i<nStartPos.length;i++) C8O7i[uc  
fileSplitterFetch.splitterStop(); w/)e2CH  
;w>Q{z  
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} lU
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} ci#Zvhtkr  
//负责部分文件的抓取 ~M|NzK_9  
**FileSplitterFetch.java O p!  
*/ <<~lV5  
package NetFox; ^*j[&:d  
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import java.io.*; [0( E>vm  
import java.net.*; xV }:M  
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public class FileSplitterFetch extends Thread { IX > j8z[  
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String sURL; //File URL |^>L`6uo  
long nStartPos; //File Snippet Start Position ^$g],PAY  
long nEndPos; //File Snippet End Position W,L>'$#pM  
int nThreadID; //Thread's ID U/v"?pg[  
boolean bDownOver = false; //Downing is over 
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boolean bStop = false; //Stop identical ?et0W|^k  
FileAccessI fileAccessI = null; //File Access interface
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4@ydK  
{ ;+#za?w  
this.sURL = sURL; M,=@
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this.nStartPos = nStart; {g23[$X]N  
this.nEndPos = nEnd; I{Y {
  
nThreadID = id; xP|%rl4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 c+YYM :S  
} R  oF  
v{\n^|=])  
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public void run() B[2h   
{ _ cHV3cz  
while(nStartPos < nEndPos && !bStop) Dg];(c+/  
{ `i_L?C7  
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try{ -hJ>wGI  
URL url = new URL(sURL); HquB*=^xh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nATfmUN L  
httpConnection.setRequestProperty("User-Agent","NetFox"); \I`=JKYT  
String sProperty = "bytes="+nStartPos+"-"; 6>P  
httpConnection.setRequestProperty("RANGE",sProperty); 8{U]ATx'(  
Utility.log(sProperty); !Barc,kA  
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InputStream input = httpConnection.getInputStream(); U- UV<}  
//logResponseHead(httpConnection); , L AJ  
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byte[] b = new byte[1024]; d~xU?)n)  
int nRead; F"HI>t)>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i32_ZBZ?y  
{ (Mire%$h  
nStartPos += fileAccessI.write(b,0,nRead); '"G %0y  
//if(nThreadID == 1) WP#_qqO  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ""U?#<}GD  
} t,r&SrC  
8=zM~v)   
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Utility.log("Thread " + nThreadID + " is over!"); W@uH!n>k  
bDownOver = true; 3Wtv+L7Br  
//nPos = fileAccessI.write (b,0,nRead); `!>dbR&1  
} Jr*S2z<*  
catch(Exception e){e.printStackTrace ();} U
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} ky lr
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} ^|hRu{QW  
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//打印回应的头信息 1RUbY>K#U  
public void logResponseHead(HttpURLConnection con) (fI&(";t  
{ #B.w
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for(int i=1;;i++) KE)D =P  
{ 3I{ta/(  
String header=con.getHeaderFieldKey(i); )su
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if(header!=null) IP4b[|ef  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); TF iM[  
Utility.log(header+" : "+con.getHeaderField(header)); &s}@7htE  
else %
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break; <:yq~?  
} 6^z\;,p  
} i[BR(D&l_p  
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public void splitterStop() {J6sM$aj  
{ ^TCJh^4na  
bStop = true; j[=_1~u}  
} pGcx jm  
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} :`"T Eif  
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/* 3K20f8g  
**FileAccess.java w)y9!li  
*//文件访问(定位，写)  _I}L$  
package NetFox; gBiQIhz  
import java.io.*; r(2'0JQ  
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{ `|YX_HS  
public class FileAccessI implements Serializable{ <W[8k-yOV`  
sq6%=(q(?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Sph"w08  
RandomAccessFile oSavedFile; bZlLivi  
long nPos; 1S.e5{  
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public FileAccessI() throws IOException a):Run  
{
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this("",0); wj:3  
} HtXBaIl\  
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public FileAccessI(String sName,long nPos) throws IOException !m:PBl5  
{ ![D,8]GD  
oSavedFile = new RandomAccessFile(sName,"rw"); 'UG}E@G  
this.nPos = nPos; ]!
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oSavedFile.seek(nPos); {
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} WyJfF=<  
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public synchronized int write(byte[] b,int nStart,int nLen) ht)*Ync  
{ IEr`6|X  
int n = -1; ,4T$  
try{ 'e)ze^Jq  
oSavedFile.write(b,nStart,nLen); yc4f\0B/  
n = nLen; y#Sw>-zRq  
} 0B:{4Lsn&  
catch(IOException e) |3lAye,t)a  
{ <UHWy&+z&  
e.printStackTrace (); |b@A:8ss  
} B+$Q"  

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l \n:"*To  
return n; MdboWE5i  
} :-@P3F[0  
d*:qFq_  
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} wQuaB6E  
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]fS~N9B  
/*
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**SiteInfoBean.java w[vIPlSdS  
*/ x4A~MuGU  
package NetFox; wQS w&G  
$ 5-2cL  
@
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public class SiteInfoBean { LuQ M$/i  
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private String sSiteURL; //Site's URL 5@rqU(]<  
private String sFilePath; //Saved File's Path )w?$~q  
private String sFileName; //Saved File's Name M~Dc5\T  
private int nSplitter; //Count of Splited Downloading File f#Oz("d  
%=O!K>^vt<  
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public SiteInfoBean() ef;="N  
{//nSplitter的缺省值为5 'xI+kyu  
//default value of nSplitter is 5 cYn}we}7  
this("","","",5); N6 (w<b  
} &r%^wfp  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'R5l =Wf  
{ WWD@rnsVf  
sSiteURL= sURL; moI<b\G@  
sFilePath = sPath; _7HJ'  
sFileName = sName; OiEaVPSI;  
this.nSplitter = nSpiltter; )g^Ewzy^X  
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} zVLi  

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public String getSSiteURL() J|8YB3K,  
{ y'wW2U/1-  
return sSiteURL; '=Y~Ir+  
} P>Rqy  
7+r5?h|  
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public void setSSiteURL(String value) <Py/uF|  
{ -7VV5W  
sSiteURL = value; e1}0f8%  
} nW*Oo|p~=  
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HD|)D5wH|  
public String getSFilePath() 4c@F.I  
{ 'E8Qi'g  
return sFilePath; w.-i !Ls  
} 6x8|v7cMH  
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public void setSFilePath(String value) iPYlTV  
{ wf$ JuHPt  
sFilePath = value; (W/UR9x)|d  
} e2ZUl` {g  
L KR,CPz  
,R6$SrNcd  
public String getSFileName() ZWEzL$VWi  
{ F4gc_>{|  
return sFileName; !qve1H4d2  
} t4f\0`jN  
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public void setSFileName(String value) "evV/Fg(  
{ &"n9,$  
sFileName = value; SVz.d/3Y  
} }CqIKoX.  
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public int getNSplitter() -e\56%\~_  
{ 4;{CR. D  
return nSplitter; f#b[KB^Z,2  
} GdY^}TJrh  
"S#hzrEdYI  
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public void setNSplitter(int nCount) 7J/3O[2  
{ A*;h}\n  
nSplitter = nCount;
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} 6* w;xf  
} _ RT}Ee}Y  
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/* HEN9D/O=  
**Utility.java U%l{>*
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*/ .C?gnOq  
package NetFox;
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public class Utility { ? GW3E  
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public Utility() Ne_>%P
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{ Jq)k?WS  
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} OD|&qsbL  
i[J',  
//线程睡眠 %R>MSSjvr  
public static void sleep(int nSecond) GjBQxn  
{ R?I3xb  
try{ +__Rk1CVh  
Thread.sleep(nSecond); S0yT%V  
} uM#/  
catch(Exception e) mQJGKh&Pk  
{ 1qF.0  
e.printStackTrace (); XwMC/]lK<  
} d?.x./1[qi  
} R\?!r4  
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//日志 24fWj?A|^  
public static void log(String sMsg) { q<l]jn9  
{ v>R.ou(  
System.err.println(sMsg);
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} [XK"$C]jHJ  
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public static void log(int sMsg) ,5:86'p  
{ +0DIN4Y(4  
System.err.println(sMsg); C54)eT6  
} _u; UU$~  
} HL]?CWtGP  
\Qn8"I83AV  
P
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/* huIr*)r&p  
**TestMethod.java OMU#Sx!6  
*/ {[+gM?  
package NetFox; LtBH4A  
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public class TestMethod { r{
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<[bDNe["?  
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public TestMethod() ;z#9>99rH  
{ ///xx/weblogic60b2_win.exe {JJ`|*H$_  
try{ *(rE<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); l{4\Wn Va  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *?K=;$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (ym)q#^  
fileFetch.start(); I$&/?ns@O  
} PhQD}|S  
catch(Exception e){e.printStackTrace ();} M}>q>  
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frt?*|:  
} iy 5  
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public static void main(String[] args) jWz-7BO  
{ 1N&U{#4  
new TestMethod(); U&NOf;h$  
} nJnan,`W  
} FYJB.lAT  
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