http断点续传简单实现（java)

/* !t{3IE  
**SiteFileFetch.java 7<oLe3fbM  
*/ 'u{m37ZJ  
package NetFox; uY,&lX+!  
import java.io.*; m]+g[L?-  
import java.net.*; Xp
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public class SiteFileFetch extends Thread { +%=Ao6/#  
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SiteInfoBean siteInfoBean = null; //文件信息Bean T c4N\Cy  
long[] nStartPos; //开始位置 h2zuPgz,  
long[] nEndPos; //结束位置 eRD?O  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Z+=WgEu1  
long nFileLength; //文件长度 jnYFA[Ab  
boolean bFirst = true; //是否第一次取文件 hUcG3IOBf  
boolean bStop = false; //停止标志 q[n
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File tmpFile; //文件下载的临时信息 .KGW#Qk8  
DataOutputStream output; //输出到文件的输出流 _+S`[:;a  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uR|Jn)/m(  
public SiteFileFetch(SiteInfoBean bean) throws IOException mZDrvTI'  
{ B9/x?Jv1  
siteInfoBean = bean; gdRwh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3205gI,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;+g p#&i`  
if(tmpFile.exists ()) p-GlGEt_X  
{ :;t*:iG  
bFirst = false; j08}5Eo  
read_nPos(); cXFNX<  
} zy~vw6vu  
else Ka&[ Oz<w  
{ E9;cd$}K  
nStartPos = new long[bean.getNSplitter()]; !krbGpTVH  
nEndPos = new long[bean.getNSplitter()]; mEmz
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} ~z$vF  
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} ='q:Io?T  
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public void run() V~tq _  
{ %<CahzYc6  
//获得文件长度 `$\g8Mo  
//分割文件 a?/GEfd  
//实例FileSplitterFetch Fd":\7p  
//启动FileSplitterFetch线程 $-[V
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//等待子线程返回 Q<3=s6@T  
try{ XZLo*C!MG  
if(bFirst) @tWyc%t  
{ cJd~UQ<k  
nFileLength = getFileSize(); t8DySFT  
if(nFileLength == -1)  iUJqAi1o  
{ :3M2zV cf  
System.err.println("File Length is not known!"); Q3vC^}Dmr  
} 4d#w}  
else if(nFileLength == -2) L}*:,&Y/  
{ {O9CYP:  
System.err.println("File is not access!"); [x ?38  
} JziuwL5,  
else wN\%b}pp  
{ o@mZ6!ax3  
for(int i=0;i<nStartPos.length;i++) n#[-1(P  
{ k3h
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); l5F>v!NA  
} D]S@U>]M!  
for(int i=0;i<nEndPos.length-1;i++)  h%0/j  
{ 3JVENn9  
nEndPos = nStartPos[i+1]; T&c0j(  
} O}I8P")m  
nEndPos[nEndPos.length-1] = nFileLength; =T;>$&qs  
} D0Yl?LU3  
} 5@ecZ2`)+h  
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//启动子线程 u[q1]]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -B-?z?+(O  
for(int i=0;i<nStartPos.length;i++) l2QO\O I9m  
{ ]fvU}4!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4nQk*:p(X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =p,+a/*  
nStartPos,nEndPos,i); WL$nchS9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v!n\A}^:  
fileSplitterFetch.start(); d0$dQg  
} 23 j{bK  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~N2){0j4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j&6'sg;n)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2`hc0 IE  
nEndPos = " + nFileLength); C` ?6`$Y  
// fileSplitterFetch[nPos.length-1].start(); 86NAa6BW  
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7\m.xWX e  
//等待子线程结束 sVtxh
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//int count = 0; <`,pyvR Kv  
//是否结束while循环 ,S5tkTa  
boolean breakWhile = false; M24FuS  
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while(!bStop) q"xIW0Pc  
{ #va|&QBZxM  
write_nPos(); dR~4*59Bg  
Utility.sleep(500); VN`T:!&  
breakWhile = true; &$F4/2|b%  
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for(int i=0;i<nStartPos.length;i++) sf
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{ I;H6E  
if(!fileSplitterFetch.bDownOver) {* S8n09v  
{ 9s\(yC8h  
breakWhile = false; Gh}k9-L  
break; ?w6zq|  
} ?&#z3c$}  
} "^E/N},%u5  
if(breakWhile) ^DVj_&~  
break; \pI)tnu6'U  
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//count++; 8m,PsUp7  
//if(count>4) ]"bkB+I  
// siteStop(); `L p3snS  
} [0|g3K!A  
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System.err.println("文件下载结束！"); %-ih$ZY  
} n';"c;Ye)  
catch(Exception e){e.printStackTrace ();} 6J. [9#  
} hnWo.5;$  
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//获得文件长度 mNkS!(L6  
public long getFileSize() ]jo^P5\h>  
{ +g36,!q  
int nFileLength = -1; r,}U-S.w  
try{ xK4b(KJj  
URL url = new URL(siteInfoBean.getSSiteURL()); Cb}hE ro  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,VZ;=  
httpConnection.setRequestProperty("User-Agent","NetFox"); b;$ -s \%  
^]mwL)I}  
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int responseCode=httpConnection.getResponseCode(); vd7%#sHH&  
if(responseCode>=400) OiPE,sv  
{ RqTW$94RD  
processErrorCode(responseCode); Q*wub9  
return -2; //-2 represent access is error Dw}8c
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} :$Lu V5  
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String sHeader; ]{0R0Gr94  
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for(int i=1;;i++) s8w7/*<d  
{ -:9E+b  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @ yJ/!9?^  
//Utility.log(in.readLine()); ,a_F[uK  
sHeader=httpConnection.getHeaderFieldKey(i); G<.p".o4  
if(sHeader!=null) ydp
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{ I#(D.\P  
if(sHeader.equals("Content-Length")) Xh==F:  
{ $<^4G  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); q^}QwJw  
break; P;jl!o$  
} |a@$K
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} gE8=#%1<  
else b~\gV_Z  
break; ;OW`(jC  
} /|] %0B  
} c_b^t09  
catch(IOException e){e.printStackTrace ();} T xRa&1  
catch(Exception e){e.printStackTrace ();} `X?l`H;#  
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Utility.log(nFileLength); k1y&'3%  
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return nFileLength; GCul6,w  
} p1t9s N,  
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//保存下载信息（文件指针位置） NC::;e  
private void write_nPos() R{S{N2+p(  
{ b\~rL,7(  
try{ Eugt~j3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q%4>okj,  
output.writeInt(nStartPos.length); O6gI%Jdp  
for(int i=0;i<nStartPos.length;i++) 88Yp0T<1  
{ %Bg} a  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); w C]yE\P1
 
output.writeLong(fileSplitterFetch.nEndPos); >69xl^Gd  
} R7cY$K{j  
output.close(); 5o\yhYS:  
} '7[{ISBXU  
catch(IOException e){e.printStackTrace ();} En3Q%  
catch(Exception e){e.printStackTrace ();} @TC_XU)&  
} :av6*&+  
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//读取保存的下载信息（文件指针位置） `/ix[:}m^  
private void read_nPos() P7d" E  
{ 4lC:svF  
try{ Q/4g)(~J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1R9hA7y&,/  
int nCount = input.readInt(); LoUi Yf  
nStartPos = new long[nCount]; C)`ZI8  
nEndPos = new long[nCount]; |mV*HdqU  
for(int i=0;i<nStartPos.length;i++) s&Y~48{  
{ ;hNnF&l  
nStartPos = input.readLong(); 4\<[y]pv  
nEndPos = input.readLong(); `Q6@,-(3  
} HB`u@9le  
input.close(); c ;`  
} l/;O
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catch(IOException e){e.printStackTrace ();} oH!sJ&"#_  
catch(Exception e){e.printStackTrace ();} 4W}8?&T  
} 4%2QF F@  
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private void processErrorCode(int nErrorCode) %stZ'
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{ 3nf+imAF  
System.err.println("Error Code : " + nErrorCode); VztalwI  
} 6N\~0d>5m  
1eI>Yy>}  
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//停止文件下载 AS`0.RC-  
public void siteStop() By6C+)up  
{ VcIsAK".4[  
bStop = true; & PrV+Lv  
for(int i=0;i<nStartPos.length;i++) F>2t=r*9  
fileSplitterFetch.splitterStop(); b")&"o)G2W  
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} QsI#Ae,O#;  
} BIDmZU9tL  
//负责部分文件的抓取 K+Al8L?K_  
**FileSplitterFetch.java T^S|u8f  
*/ -\\}K\*MJ  
package NetFox; Xj"/6|X  
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import java.io.*; 
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import java.net.*; P1=bbMk  
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public class FileSplitterFetch extends Thread { 4z Af|Je  
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String sURL; //File URL \`jFy[(Pa'  
long nStartPos; //File Snippet Start Position D}px=?  
long nEndPos; //File Snippet End Position COc1np  
int nThreadID; //Thread's ID vTQQd@  
boolean bDownOver = false; //Downing is over R}Uvi9?  
boolean bStop = false; //Stop identical ~ygiKsD6b  
FileAccessI fileAccessI = null; //File Access interface t= "EbPE  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 'IFbD["r  
{ 0aSN8  
this.sURL = sURL; 39S}/S)  
this.nStartPos = nStart; @jN!j*Y H  
this.nEndPos = nEnd; =r3Yt9  
nThreadID = id; l Vo](#W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 F0o7X
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} MG[?C2KA/  
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public void run() Df||#u=n  
{ m/=,O_  
while(nStartPos < nEndPos && !bStop) 
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{ hz<kR@k}  
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try{ k<ku5U1|
 
URL url = new URL(sURL); s!nFc{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /$\yAOA'y  
httpConnection.setRequestProperty("User-Agent","NetFox"); I|m fr{  
String sProperty = "bytes="+nStartPos+"-"; %<O'\&!,  
httpConnection.setRequestProperty("RANGE",sProperty); 7.CzS  
Utility.log(sProperty); {3yzC  
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InputStream input = httpConnection.getInputStream(); k`Ab*M$@Xs  
//logResponseHead(httpConnection); SEr\ u#  
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byte[] b = new byte[1024]; Ooc,R(  
int nRead; ScQJsFE6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cInzwdh7  
{ gmLGK1  
nStartPos += fileAccessI.write(b,0,nRead); yrR<F5xge  
//if(nThreadID == 1) ,@
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,COSpq]6  
} =\J^_g4-l  
?#ndMv!$  
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Utility.log("Thread " + nThreadID + " is over!"); ;x@9@6_  
bDownOver = true; f5 wn`a~h  
//nPos = fileAccessI.write (b,0,nRead); #lM!s  
} pTOS}A[dh  
catch(Exception e){e.printStackTrace ();} t&mw@bj  
} mc?5,oz;pz  
} W~.1f1)  
L

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//打印回应的头信息 r|fJ~0z  
public void logResponseHead(HttpURLConnection con) p!AQ
  
{ 1FjA  
for(int i=1;;i++) |bi"J;y  
{ nFzhj%Pt;  
String header=con.getHeaderFieldKey(i); (jPN+yQ  
if(header!=null) 3VCyq7B^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d5T0#ue/e  
Utility.log(header+" : "+con.getHeaderField(header)); Fq&@dxN3  
else 1e'-rm F  
break; i'L7t!f}o  
} pHsp]a  
} x(hUQu 6  
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public void splitterStop() TA`*]*O(  
{ b?CmKiM%  
bStop = true; CP7Zin1S/w  
} xRv1zHZ  
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} 5ii`!y  
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/* NqkRR$O  
**FileAccess.java JXftQOn  
*//文件访问(定位，写) 2OAh7'8<  
package NetFox; 6y%BJU.I  
import java.io.*; rP2^D[uM.  
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public class FileAccessI implements Serializable{ l#~Sh3@L(  
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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 T d4/3k  
RandomAccessFile oSavedFile; {h&*H[Z z  
long nPos; +m:U9K(\h  
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public FileAccessI() throws IOException 9D(M>'Bh  
{ AjAmV hq  
this("",0); 7T_g?!sdMh  
} x\3 ` W  
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public FileAccessI(String sName,long nPos) throws IOException ,{%/$7)  
{ qq[2h~6
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oSavedFile = new RandomAccessFile(sName,"rw"); .oaW#f}0P  
this.nPos = nPos; A. U<  
oSavedFile.seek(nPos); @r+ErFI  
} GQ2&D}zh  
z;#}uC  
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public synchronized int write(byte[] b,int nStart,int nLen) []3xb`<&  
{ hB P]^~(  
int n = -1; qAR~js`5  
try{ VG&|fekF  
oSavedFile.write(b,nStart,nLen); 6\4oHRJC  
n = nLen; S,G=MI"  
} fR6ot#b  
catch(IOException e) Fdm7k){A  
{ MukPY2[Am  
e.printStackTrace (); Z>o;Yf[  
} kVkV~  
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return n; C([;JO 11[  
} v}xz`]MW<,  
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} FxM`$n~K  
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/* \
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**SiteInfoBean.java "h$A.S  
*/ Yx(?KN7V?  
package NetFox; YOGwQ  
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public class SiteInfoBean { yHr/i
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/ DeIs  
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private String sSiteURL; //Site's URL VG2TiR1  
private String sFilePath; //Saved File's Path D?@330'P9C  
private String sFileName; //Saved File's Name KNIYar*3  
private int nSplitter; //Count of Splited Downloading File vq(@B  
J24UUZ9&$  
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public SiteInfoBean() u6t.$a!5  
{//nSplitter的缺省值为5 pL-p  
//default value of nSplitter is 5 xzW]D0o0  
this("","","",5); ^uIZs}=+  
} ;OPzT9  
ws?p2$Cla  
}(op;7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g3LAi#m  
{ N=tyaS(YJ
 
sSiteURL= sURL; "*%=k%'
 
sFilePath = sPath; cQ*:U@  
sFileName = sName; oIoJBn  
this.nSplitter = nSpiltter; S@N&W&W#~  
#`y7L4V*o  
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} 9p2"5x  
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public String getSSiteURL() z[z'.{;D  
{ p*#SSR9<  
return sSiteURL; [7|}h/  
} ;op+~@*!  
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public void setSSiteURL(String value) Ug3PZ7lK  
{ -Zocu<Rs  
sSiteURL = value; ;#`Z(A}  
} f7d)  
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xx!o]D-}  
public String getSFilePath() >/5D/}4  
{ ;`X-.45  
return sFilePath; kl3#&>e  
} dE/Vl/:  
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public void setSFilePath(String value) 2}~1poyi>  
{ ',m,wp`  
sFilePath = value; `j_R ?mY  
} <| Xf4.  
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public String getSFileName() 8{%/!ylJz  
{ N7+K$)3  
return sFileName; 0)k%nIhj  
} j(/"}d3osm  
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public void setSFileName(String value) h^x7[qe  
{ cl:*Q{(Cjk  
sFileName = value; AGK+~EjL@  
} g@B9i=  
#\%GrtM  
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public int getNSplitter() ;)"r^M)):  
{ MSRIG-  
return nSplitter; [OH>NpL  
} T_v  
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public void setNSplitter(int nCount) G\jr^d\  
{ 5XFhjVmEL  
nSplitter = nCount; (Clf]\_II  
} k(%RX_]C  
} $dorE~T  
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@  
/* ,_\h)R_  
**Utility.java <0v'IHlZ8  
*/ .N/4+[2p(  
package NetFox; /~gM,*  
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public class Utility { eA{,=,v)  
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public Utility() 4.H!rkMM  
{ ``ao
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} ]vKxgfF  
7F}I.,<W  
//线程睡眠 rrbCg(  
public static void sleep(int nSecond) -W+dsZ Sv8  
{ Srol0D I  
try{ mz9Kwxe  
Thread.sleep(nSecond); {D`F$=Dlw  
} w$61+KHK  
catch(Exception e)  b$rBxe\  
{ zx=A3I%7 A  
e.printStackTrace (); 1REq.%/=  
} 6D0uLh  
} P5] cEZ n  
*$^ME  
//日志 nU`vj`K   
public static void log(String sMsg)  "thfd"-  
{ G>#L  
System.err.println(sMsg); kE6\G}zj  
} g\ <Lb  
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public static void log(int sMsg) v oC< /}E  
{ :V+t|@m5l  
System.err.println(sMsg); `pII-dSC%  
} r
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} &,NHk9.aq  
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/* f)"O( c  
**TestMethod.java e[Q(OV5(R  
*/ ^+,mxV'8!  
package NetFox; #i)h0ML/e  
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public class TestMethod { !aLByMA  
\ZCc~muR  
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public TestMethod() ap;*qiNFQ  
{ ///xx/weblogic60b2_win.exe i$%;z~#wW  
try{ 63:ZDQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); S&
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Oe2Tmvl  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E.6^~'/  
fileFetch.start(); { 
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} __3Cjo^6&  
catch(Exception e){e.printStackTrace ();} @["Vzg!I6"  
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}  kQX,MP(  
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U%w-/!p  
public static void main(String[] args) %o^'(L@z  
{ 6pr}A  
new TestMethod(); OaU$ [Z'8  
} ?*}V>h 8m)  
} Z(Q?epyT  
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