http断点续传简单实现（java)

/* ,z6~?6m  
**SiteFileFetch.java vD4*&|8T#  
*/ )}vl\7=  
package NetFox; @nf
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import java.io.*; Hp?/a?\Xm  
import java.net.*; :KO2| v\  
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public class SiteFileFetch extends Thread { JtZ7ti  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /RF
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long[] nStartPos; //开始位置 Mihg:  
long[] nEndPos; //结束位置 ^Dx&|UwiZa  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 E"0>yl)  
long nFileLength; //文件长度 QW"! (`K  
boolean bFirst = true; //是否第一次取文件 Gh
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boolean bStop = false; //停止标志 %)wjR/o  
File tmpFile; //文件下载的临时信息 D{!IW!w  
DataOutputStream output; //输出到文件的输出流 v0y(58Rz.  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;d?R:Uw8  
public SiteFileFetch(SiteInfoBean bean) throws IOException Js;h%  
{ v>56~AJ  
siteInfoBean = bean; <vP=zk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =lC7gS!U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gFh*eCo   
if(tmpFile.exists ()) fR|A(u#9  
{
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bFirst = false; tVjsRnb{  
read_nPos(); 54/=G(F  
} H>C=zo,oiC  
else qWw=8Bq  
{ Uz7<PLxd  
nStartPos = new long[bean.getNSplitter()]; Mfs?x a  
nEndPos = new long[bean.getNSplitter()]; NO3/rJ6-  
} K%d&EYoW]  
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} [!z,lY>  
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public void run() M_8{]uo  
{ .u:GjL'$  
//获得文件长度 26nx`w?j(  
//分割文件 ceV}WN19l  
//实例FileSplitterFetch l,8##7  
//启动FileSplitterFetch线程 Vc2`b3"Br  
//等待子线程返回 RpF&\x>  
try{ SdWV3  
if(bFirst) ys~x$  
{ 40/Y
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nFileLength = getFileSize(); 1qch]1 ^G  
if(nFileLength == -1) :>*7=q=  
{ ;fJ.8C  
System.err.println("File Length is not known!"); yw!{MO  
} q@qsp&0/  
else if(nFileLength == -2) Y}/-C3)  
{ . ^u,.  
System.err.println("File is not access!"); >bxS3FCX  
} ZEQEx]Y  
else H.c7Nle  
{ R2;  
for(int i=0;i<nStartPos.length;i++) +:f"Y0  
{ n ;Ei\\p!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); G3 m Z($y  
} <[phnU^ 8  
for(int i=0;i<nEndPos.length-1;i++) <[v[ci  
{ %*U'@r(A  
nEndPos = nStartPos[i+1]; Z.WW(C.  
} iwq!w6+  
nEndPos[nEndPos.length-1] = nFileLength; }#J/fa9 !  
} <GJbmRc|  
} u y+pP!<  
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s.#`&Sd>  
//启动子线程 GVz6-T~\>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @7u0v  
for(int i=0;i<nStartPos.length;i++) \!(zrfP
{(  
{ ==B6qX8T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S@Y39  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lFkR=!?=  
nStartPos,nEndPos,i); .d*8C,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @d_M@\r=j  
fileSplitterFetch.start(); $:6!H:ty  
} )_:NLo:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6LZCgdS{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "&] -2(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", jo7\`#(Q  
nEndPos = " + nFileLength); df=f62  
// fileSplitterFetch[nPos.length-1].start(); z{543~Og59  
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//等待子线程结束 NHt\ U9l'  
//int count = 0; rA1._   
//是否结束while循环 y} '@R$  
boolean breakWhile = false; N[hG8f  
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while(!bStop) pYg/Zm Jd  
{ @iiT
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write_nPos(); )+^+sd  
Utility.sleep(500); _{>vTBU4F  
breakWhile = true; =wJX0A|  
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for(int i=0;i<nStartPos.length;i++) o-\[,}T)M  
{ s"|Pdc4  
if(!fileSplitterFetch.bDownOver) Wqnc{oq|$  
{ #tHK"20  
breakWhile = false; =I<R!ZSN  
break; }bDm@NU  
} hp2t"t  
} m
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if(breakWhile) #E[0ys1O  
break; x2EUr,7  
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//count++; #WuBL_nZ~  
//if(count>4) txpgO1  
// siteStop(); /z!%d%"  
} w]H->B29C  
:/#rZPPF  
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System.err.println("文件下载结束！"); LLo;\WGZ  
} }EPY^VIw  
catch(Exception e){e.printStackTrace ();} r$1Qf}J3=  
} .H|-_~Yx|  
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//获得文件长度 PsYpxNr  
public long getFileSize() M{@(G5  
{ 8mMQ[#0:}  
int nFileLength = -1; S!UaH>Rh  
try{ ^c<Ve'-
 
URL url = new URL(siteInfoBean.getSSiteURL()); %4H%?4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pkzaNY/q  
httpConnection.setRequestProperty("User-Agent","NetFox"); %{|pj +  
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int responseCode=httpConnection.getResponseCode(); ![1rzQvGDb  
if(responseCode>=400) ]`K2N  
{ X, n:,'  
processErrorCode(responseCode); Oz95  
return -2; //-2 represent access is error Nc`L;CP  
} "x-j~u?  
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String sHeader; f8~_E  
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for(int i=1;;i++) w>gYx(8b  
{ 2ESo2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5+'<R8{:,  
//Utility.log(in.readLine()); i@yC-))bY  
sHeader=httpConnection.getHeaderFieldKey(i); G
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if(sHeader!=null) K-4PI+qQ\  
{ CZ;6@{ o  
if(sHeader.equals("Content-Length")) UN
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{ 5+vaE 2v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); AH^/V}9H  
break; d0D]Q  
} &Jj<h: *  
} ;pAK_>
 
else Y]>t[Lo%  
break; *w&e\i|7  
} qPNR`%}Q  
} Hs8>anVo[  
catch(IOException e){e.printStackTrace ();} A^g(k5M*  
catch(Exception e){e.printStackTrace ();} TOt dUO  
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Utility.log(nFileLength); 3`g^  
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return nFileLength; 4Z*/WsCv  
} :;}P*T*PU  
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//保存下载信息（文件指针位置） lxx2H1([  
private void write_nPos() FrS]|=LJhX  
{ ^q5#ihM  
try{ N8jIMb'<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (QEG4&9  
output.writeInt(nStartPos.length); Y2AJ+ |  
for(int i=0;i<nStartPos.length;i++) 4(+PD&_J  
{ Z@HEj_n  
// output.writeLong(nPos); B\~}3!j  
output.writeLong(fileSplitterFetch.nStartPos); -
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output.writeLong(fileSplitterFetch.nEndPos); K;?+8(H  
} XFl6M~ c  
output.close(); 7!1S)dup  
} D.:Zx  
catch(IOException e){e.printStackTrace ();} ?<!|  
catch(Exception e){e.printStackTrace ();} )lkjqFQ(  
} kiEa<-]  
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//读取保存的下载信息（文件指针位置） >4TO=i  
private void read_nPos() K(4_a``05  
{ =_CzH(=f#  
try{ 00
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _a, s )  
int nCount = input.readInt(); .-zom~N-?  
nStartPos = new long[nCount]; UQsN'r\tS  
nEndPos = new long[nCount]; -"x$ZnHU  
for(int i=0;i<nStartPos.length;i++) )%TmAaj9d  
{ 6tZI["\   
nStartPos = input.readLong(); KI.unP%  
nEndPos = input.readLong(); _`X:jj>  
} tQVVhXQ7  
input.close(); 5P bW[  
} [),ige  
catch(IOException e){e.printStackTrace ();} :jf3HG  
catch(Exception e){e.printStackTrace ();} Wwo0%<2y  
} vN $s|R'@  
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private void processErrorCode(int nErrorCode) gYj'(jB  
{ \U0Q<ot/7  
System.err.println("Error Code : " + nErrorCode); BtZyn7a  
} SbZ6t$"  
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[[ZJ]^n,  
//停止文件下载 !D6]J
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public void siteStop() "@kaHIf[  
{ `cO:<^%  
bStop = true; }H4RR}g  
for(int i=0;i<nStartPos.length;i++) kAx4fE[c  
fileSplitterFetch.splitterStop(); bt *k.=p  
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} a*;b^Ze`v  
}
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//负责部分文件的抓取 =Qq+4F)MD  
**FileSplitterFetch.java ESs\O?nO  
*/ *:
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package NetFox; ,Q B
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import java.io.*; oU|c
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import java.net.*; mOSv9w#,  
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public class FileSplitterFetch extends Thread { )"LJ hLg  
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String sURL; //File URL neh(<>  
long nStartPos; //File Snippet Start Position tkhCw/  
long nEndPos; //File Snippet End Position wBzC5T%,  
int nThreadID; //Thread's ID AGno6
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boolean bDownOver = false; //Downing is over iE{&*.q_}>  
boolean bStop = false; //Stop identical *"kM{*3:v  
FileAccessI fileAccessI = null; //File Access interface hph4`{T  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException l,:F  
{ X8|EHb<  
this.sURL = sURL; +V+a4lU14  
this.nStartPos = nStart; f)!Z~t &  
this.nEndPos = nEnd;
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nThreadID = id; F?cK-.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BHw, 4#F1;  
} ]9XDS[<2`  
_
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public void run() r/sNrB1U"y  
{ X.V~SeS  
while(nStartPos < nEndPos && !bStop) ]?)TdJ`  
{ z=FZiH  
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try{ +3`alHUK  
URL url = new URL(sURL); H[UlY?&+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2(nlJ7R  
httpConnection.setRequestProperty("User-Agent","NetFox"); fatf*}eln  
String sProperty = "bytes="+nStartPos+"-"; DN/YHSYK  
httpConnection.setRequestProperty("RANGE",sProperty); XM}hUJJW  
Utility.log(sProperty); vj*%Q(E6Pt  
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InputStream input = httpConnection.getInputStream(); .G^YqJ 4  
//logResponseHead(httpConnection); J=L5=G7(  
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byte[] b = new byte[1024]; ^J d r>@  
int nRead; 2[CdZ(k]5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) PzGWff!*n  
{ aoTP[Bp  
nStartPos += fileAccessI.write(b,0,nRead); tjnIN?YT  
//if(nThreadID == 1) }`"6aM   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Kg$Mx  
} ??T#QQ
 
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Utility.log("Thread " + nThreadID + " is over!"); :L;a:xSpn=  
bDownOver = true;  }75e:w[  
//nPos = fileAccessI.write (b,0,nRead); TPY}C  
} :Yks|VJ1  
catch(Exception e){e.printStackTrace ();} tl].r|yl  
} ?s _
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} 6&-(&(_  
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7)k\{&+P  
//打印回应的头信息 xvy.=(  
public void logResponseHead(HttpURLConnection con) =ruao'A  
{ PT9*)9<L  
for(int i=1;;i++) ~nPtlrQa#*  
{ Lxk[;j+  
String header=con.getHeaderFieldKey(i); ZW}_Qs  
if(header!=null) N!|wo:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); n}V_,:Z  
Utility.log(header+" : "+con.getHeaderField(header)); 5Dl/aHb  
else u4_9)P`]0  
break; veRm2LSP  
} pD74+/DD  
} J'2X&2  
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public void splitterStop() @gtQQxf"  
{ ~!3r&(  
bStop = true; 9$m|'$p3sG  
} xRsWI!d+|  
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} p[lA\@l[  
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/* pXK^Y'2C!  
**FileAccess.java 0{[,E.  
*//文件访问(定位，写) BV+ Bk+  
package NetFox; (2 a`XwR  
import java.io.*; {GcO3G#FZ  
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public class FileAccessI implements Serializable{ <1COZ)  
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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 o\)F}j&b#=  
RandomAccessFile oSavedFile; u=_mvN  
long nPos; bD8Gwi=iiu  
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public FileAccessI() throws IOException ^Js9 s8?$  
{ %-e 82J1  
this("",0); )D82N`c2\i  
} {T Ug.%u  
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public FileAccessI(String sName,long nPos) throws IOException D+7Rz_=  
{ mcX/GO}  
oSavedFile = new RandomAccessFile(sName,"rw"); Clb@$,  
this.nPos = nPos; }k G9!sf  
oSavedFile.seek(nPos); A7hVHxNJ-  
} R#8L\1l  
 ?_"ik[w}  
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public synchronized int write(byte[] b,int nStart,int nLen) Yr=Y@~ XL  
{ hzbw>g+  
int n = -1; A:9?ZI/X  
try{ \qK&q  
oSavedFile.write(b,nStart,nLen); :+|Z@KB  
n = nLen; g]yBA7/S"  
} R= o2K  
catch(IOException e) %(G* ,  
{ 7y@Pa&^8  
e.printStackTrace (); )$bS}.  
} @)&=%  
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return n; ^vO+
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} Eq\M;aDq  
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} dg"3rs /?A  
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/* K]"#C  
**SiteInfoBean.java P8)=Kbd  
*/ Q_X.rUL0w  
package NetFox; 6U,O*WJ%e  
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public class SiteInfoBean { pF Rg?-  
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private String sSiteURL; //Site's URL `Kr,>sEAM  
private String sFilePath; //Saved File's Path emPM4iG?!  
private String sFileName; //Saved File's Name /M4{Wc  
private int nSplitter; //Count of Splited Downloading File <\ :Yk  
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public SiteInfoBean() f;gw"onx8F  
{//nSplitter的缺省值为5 k$J zH$  
//default value of nSplitter is 5 sN2p76KN  
this("","","",5); n}G|/v<  
} =U|.^5sa#  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {~sDYRX  
{ ^o1*a&~J@  
sSiteURL= sURL; a$"Hvrj  
sFilePath = sPath; a\E:sPM'>  
sFileName = sName; Dq5j1m.  
this.nSplitter = nSpiltter; 
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} ,\ k(x>oy  
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public String getSSiteURL() fM63+9I)\  
{ ~ZEmU
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return sSiteURL; dA0.v+Foz"  
} J)~L   
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public void setSSiteURL(String value) 5b[jRj6  
{ s4S
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sSiteURL = value; (>GK\=:<  
} 80/F7q'tn  
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public String getSFilePath() /8g^T")  
{ fhp<oe>D  
return sFilePath; muZ~*kMc  
} Z2='o_c  
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public void setSFilePath(String value) I'iGt~4$  
{ lM{ +!-G,  
sFilePath = value; \":m!K;Z  
} mvZw  
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public String getSFileName() (%xwl  
{ 8C~]
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return sFileName; *B{j.{ p(  
} rJ{O(n]j  
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public void setSFileName(String value) ";Rtiiu  
{ oDYRQozo>  
sFileName = value; S.q].a  
} K7Wk6Aw  
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public int getNSplitter() sHl>$Qevz  
{ yH*6@P4:0=  
return nSplitter; MR<;i2p  
} HnCzbt@  
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public void setNSplitter(int nCount) -3lb@ 6I6  
{ 'n$%Ls}S  
nSplitter = nCount; MxcFvo*LCp  
} q)vplV1A  
} mJ`A_0  
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/* JEgx@};O  
**Utility.java 1,~SS  
*/ &F5@6nJ`  
package NetFox; 'X!?vK^]p  
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public class Utility { YxinE`u~  
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public Utility() ] 0m&(9  
{ 01. &>Duw  
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} 0{PzUIM,W  
4[-*~C|W5  
//线程睡眠 -"[<ek  
public static void sleep(int nSecond) ?8mlZ X9C  
{ t 6^l`6:p  
try{ \7 NpT}dj  
Thread.sleep(nSecond); I1>N4R-j  
} (V%`k'N7f  
catch(Exception e) d@G}~&.|  
{ t"YNgC ^  
e.printStackTrace (); {E0z@D)U-  
} tpTAeQ*:d  
} %F*|;o7
s  
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//日志 G>+1*\c  
public static void log(String sMsg) Q9&kJ%Mo  
{ @hImk`&[N  
System.err.println(sMsg); FsGlJ  
} ii0Ce}8d~  
[ dE.
[  
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public static void log(int sMsg) |fY/i] Ax  
{ <JwX_\?
ln  
System.err.println(sMsg); Ep4Hqx $  
} K!mOr  
} <x),,a=X  
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/* x/:4{  
**TestMethod.java T4;T6 9j;,  
*/ 56Z\-=KAU  
package NetFox; nD2,!7
1  
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public class TestMethod { 9lo[&^<  

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public TestMethod() <d7V<&@o=  
{ ///xx/weblogic60b2_win.exe Z_1*YRBY;  
try{ Ij'NC C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -n? g~(/
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p=QYc)3F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~/tKMS6T  
fileFetch.start(); +"g~"<  
} 4E:bp   
catch(Exception e){e.printStackTrace ();} ksjUr1o  
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} ehAu^^Q>  
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public static void main(String[] args) ?Jtg3AY  
{ jec:i-,  
new TestMethod(); })IO#,  
} xqHL+W  
} :<~7y.*O{  
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