http断点续传简单实现（java)

/* qLKyr@
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**SiteFileFetch.java t*<vc]D  
*/ COFs?L.`  
package NetFox; ]l+Bg;F#V  
import java.io.*; \l{*1lQ`  
import java.net.*; mW1Sd#0  
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public class SiteFileFetch extends Thread { Zqd&EOm  
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SiteInfoBean siteInfoBean = null; //文件信息Bean y4VCehdJ  
long[] nStartPos; //开始位置 D[7K2G+  
long[] nEndPos; //结束位置 a%tm[Re  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <Nvw w  
long nFileLength; //文件长度 -6~*:zg,  
boolean bFirst = true; //是否第一次取文件 ,TOLr%+v~n  
boolean bStop = false; //停止标志 seHwn'Jn  
File tmpFile; //文件下载的临时信息 9Q]v#&1  
DataOutputStream output; //输出到文件的输出流 %2BFbaE  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @5 kKMz  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9/}i6j8Z  
{ s7I*=}{g0.  
siteInfoBean = bean; ,p1 (0i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); & /-@R|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .`Z{ptt>  
if(tmpFile.exists ()) k}ps-w6:  
{ }yx{13:[  
bFirst = false; cLr? B;FS  
read_nPos(); <Ml,H%F  
} T_Z@uZom.  
else _I~TpH^1K  
{ ;07!^#:L=Q  
nStartPos = new long[bean.getNSplitter()]; ;DC0LJ  
nEndPos = new long[bean.getNSplitter()]; au"HIyi?k  
} "c!s\iuBU  
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} .~v~~VL1NS  
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public void run() |r}%AN6+  
{ T~"
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//获得文件长度 ZhxMA*fL  
//分割文件 +D?d)lK  
//实例FileSplitterFetch :N8D1e-a  
//启动FileSplitterFetch线程 <kLY1EILM  
//等待子线程返回 8S]Mf*~S'  
try{ &M>S$+I n  
if(bFirst) e7,iO#@:m  
{ Redp'rXT<h  
nFileLength = getFileSize(); a:zx&DwM  
if(nFileLength == -1) (ZShhy8g  
{ pal))e!B  
System.err.println("File Length is not known!"); FVY,CeA.  
} WU<#_by g  
else if(nFileLength == -2) H7Y}qP5X  
{ C| Mh<,~E  
System.err.println("File is not access!"); +V2a|uvEc  
} rA`zuYo  
else LvWU %
?  
{ GZZLX19sq  
for(int i=0;i<nStartPos.length;i++) |]GEJUWtCd  
{ '0t j2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ATnD~iACY  
} Jk{>*jYk`  
for(int i=0;i<nEndPos.length-1;i++) 3BY/&'oX  
{ q/;mxq$  
nEndPos = nStartPos[i+1]; v[Q)cqj/  
} .&sguAyG  
nEndPos[nEndPos.length-1] = nFileLength; E*(Q'p9C  
} GGJ_,S*  
} K"}Dbr  
\W=  
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//启动子线程 cYbO)?mC_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +D h=D*  
for(int i=0;i<nStartPos.length;i++) I]k'0LG*^  
{ {_q2kk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 46XB6z01  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N23s{S t  
nStartPos,nEndPos,i); }rO4b>J  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MO _9Yi  
fileSplitterFetch.start(); 8z/^Ql  
} d\)v62P  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]ei]) J
I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G x,D'H'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1c}'o*K_%  
nEndPos = " + nFileLength); +Og O<P  
// fileSplitterFetch[nPos.length-1].start(); 1Rczf(,aT  
fLD9RZ8_  
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//等待子线程结束 [w{ZP4d>  
//int count = 0; whLske-  
//是否结束while循环 R +\y".  
boolean breakWhile = false; 4k#B5^iJ  
"Y%\qw/wq  
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while(!bStop) xDQ$Ui.  
{ 2f:'~ P56  
write_nPos();
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Utility.sleep(500); 'R'>`?Nh  
breakWhile = true; w}YHCh  
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9723f1&Vd  
for(int i=0;i<nStartPos.length;i++) {>+$u"*  
{ 
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if(!fileSplitterFetch.bDownOver) ITsJjcYw  
{ bTiw?i+6Dv  
breakWhile = false; #-@{rgH  
break; JfVayI=  
} <;XJ::d  
} ]!A;-m  
if(breakWhile) K[ \z'9Q  
break; hV,3xrm?P  
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//count++; kEXcEF_9P  
//if(count>4) p0tv@8C>  
// siteStop(); v4v+;[a%  
} \;?\@vo<  
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System.err.println("文件下载结束！"); ]Yj>~k:K  
} Gg!))I+  
catch(Exception e){e.printStackTrace ();} jNyC%$  
} .Yf h*  
9.@(&  
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//获得文件长度 p;5WLAF  
public long getFileSize() b9YpUm7#  
{ +p[~hM6?  
int nFileLength = -1; 6 %=BYDF  
try{ JxvwquI  
URL url = new URL(siteInfoBean.getSSiteURL()); =3T?U_u@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }+lxja]C  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q0--.Q=:Y  
~FsUK;?  
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int responseCode=httpConnection.getResponseCode(); B.WJ6.DkS  
if(responseCode>=400) y H'\<bT  
{ ~"wD4Ue  
processErrorCode(responseCode); nY8UJy}<oL  
return -2; //-2 represent access is error q-RGplx  
} |4c==7.  
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String sHeader; XgbGC*dQ  
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for(int i=1;;i++) |HA7 C  
{ K
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &Ch)SD  
//Utility.log(in.readLine()); |HEw~x<=  
sHeader=httpConnection.getHeaderFieldKey(i); t,+S~Cj|  
if(sHeader!=null) iWCV(!  
{ s +GF-kJ*  
if(sHeader.equals("Content-Length")) IN"vi|1  
{ ##
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); YNXk32@j@e  
break; Om^/tp\  
} O7\s1 V;  
} BNy"YK$  
else 4W?<hv+k7*  
break; WAa?$"U2  
} Y;w]u_  
} }-vBRY  
catch(IOException e){e.printStackTrace ();} y(dS1.5F  
catch(Exception e){e.printStackTrace ();} Z~uKT n  
br;G5^j3?  
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Utility.log(nFileLength); ./ :86@O  
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return nFileLength; ypd?mw&1}  
} 4yA`);r62  
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//保存下载信息（文件指针位置） ]Rye AJ3  
private void write_nPos() AAW7@\q.  
{ 6:,^CI|@t  
try{ 2{CSH_"Z7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 64lEB>VNm  
output.writeInt(nStartPos.length); eTc`FXw`  
for(int i=0;i<nStartPos.length;i++) v2{O67j} o  
{ k~R[5W|'  
// output.writeLong(nPos); [FL I+;gY  
output.writeLong(fileSplitterFetch.nStartPos); , .I^ekF  
output.writeLong(fileSplitterFetch.nEndPos); 2UF94  
} mc'p-orAf  
output.close(); @"!SU'*  
} ]Yg EnZ  
catch(IOException e){e.printStackTrace ();} 5avO48;Vc  
catch(Exception e){e.printStackTrace ();} u\xm8}A  
} `$H  
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//读取保存的下载信息（文件指针位置） CiuN26>  
private void read_nPos() }#8uXA  
{
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try{ {wP|b@(1t  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fYy.>m+P1  
int nCount = input.readInt(); ^0Q*o1W  
nStartPos = new long[nCount]; yxN!*~BvL  
nEndPos = new long[nCount]; )0mDN.
  
for(int i=0;i<nStartPos.length;i++) JNaW>X$K  
{ e_], O_Z  
nStartPos = input.readLong(); pCc7T-"og  
nEndPos = input.readLong(); %B*dj9n^q  
} 2-0cB$W+  
input.close(); mPin\-I  
} B:~;7A\  
catch(IOException e){e.printStackTrace ();} \NU[DHrMP  
catch(Exception e){e.printStackTrace ();} l;A_Aii(  
} MuGg z>CV[  
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private void processErrorCode(int nErrorCode) kW&Z%k  
{ qD*\}b]9I  
System.err.println("Error Code : " + nErrorCode); sK0VT"7K  
} F5+_p@!i  
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//停止文件下载 <UJJ],)^1A  
public void siteStop() 7[BL 1HI*  
{ |nN/x<v  
bStop = true; io7U[#  
for(int i=0;i<nStartPos.length;i++) C-u/{CP  
fileSplitterFetch.splitterStop(); Ok&>[qu  
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} 1:zu$|%7  
} g@i
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//负责部分文件的抓取 4D$sFR|?t  
**FileSplitterFetch.java *\KvcRMGUa  
*/ "GI
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package NetFox; Ok
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import java.io.*; Tki/d\!+  
import java.net.*; ~88 Tz+  
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public class FileSplitterFetch extends Thread { G.nftp(*}  
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String sURL; //File URL R.IUBw5;/  
long nStartPos; //File Snippet Start Position J xm9@,  
long nEndPos; //File Snippet End Position 07Q[L'}y@  
int nThreadID; //Thread's ID FJ~_0E#L  
boolean bDownOver = false; //Downing is over :$i:8lz  
boolean bStop = false; //Stop identical MW$H/:3  
FileAccessI fileAccessI = null; //File Access interface @
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Q\#{2!I  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException b+].Uc  
{ |sqo+E  
this.sURL = sURL; H!r Kz  
this.nStartPos = nStart; }<ONxg6Kb  
this.nEndPos = nEnd; l$VxE'&LQ  
nThreadID = id;
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 >xV<nL
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} &rztC]jF  
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public void run() )^f9[5ee  
{ %}MA5 t]o  
while(nStartPos < nEndPos && !bStop) ;%7XU~<a  
{ QHs:=i~VH  
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try{ >9<8G]vcH  
URL url = new URL(sURL); O%K?l}e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @=NVOJy}c  
httpConnection.setRequestProperty("User-Agent","NetFox"); e*2&s5 #RT  
String sProperty = "bytes="+nStartPos+"-"; (Ef2 w['  
httpConnection.setRequestProperty("RANGE",sProperty); B_"OA3d_  
Utility.log(sProperty); qIGu#zXW  
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InputStream input = httpConnection.getInputStream(); YNC0Z'c9  
//logResponseHead(httpConnection); qN1 -plY  
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byte[] b = new byte[1024]; hG~]~ )  
int nRead; cxD}t'T  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p~q_0Pg%  
{ VyoE5o  
nStartPos += fileAccessI.write(b,0,nRead); >[XOMKgQ](  
//if(nThreadID == 1) c
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +# RlX3P  
} !*?(Q6  
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Utility.log("Thread " + nThreadID + " is over!"); Dl zmAN  
bDownOver = true; Sz|Y$,  
//nPos = fileAccessI.write (b,0,nRead); 85%Pq:E  
} u1;e*t
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catch(Exception e){e.printStackTrace ();} X(!AI|6Bt  
} VX!Y`y^a  
} ,"N3k(g  
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=tS[&6/  
//打印回应的头信息 TDl!qp @  
public void logResponseHead(HttpURLConnection con) hnsa)@  
{ e7XsyL'
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for(int i=1;;i++) N&I8nZ9  
{ S2'`|uI  
String header=con.getHeaderFieldKey(i); |5O >>a()  
if(header!=null) Et}C`vZ+Ve  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); lPRdwg-  
Utility.log(header+" : "+con.getHeaderField(header)); =j|v0& AGC  
else /$FXg;h9$  
break; wRXn9  
} vh|Tb5W<  
} 5W[3_P+  
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public void splitterStop() 1Lm].tq  
{ /<(*/P,>  
bStop = true; y:g7'+c  
} x{NNx:T1  
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} `ICcaRIN8I  
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/* 1z})mfsh  
**FileAccess.java -+3be(u  
*//文件访问(定位，写) h1^9tz{  
package NetFox; 1<LC8?wt  
import java.io.*; %_B:EMPd  
, @%C8Z  
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public class FileAccessI implements Serializable{ F=oHl@  
[2GXAvXsT  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 M1AZ}bc0]  
RandomAccessFile oSavedFile; :DZLjC  
long nPos; ,}9f(`  
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public FileAccessI() throws IOException hAV2F#  
{ ./"mn3U  
this("",0); *Rz{44LP&  
} ,U6*kvHS6  
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public FileAccessI(String sName,long nPos) throws IOException -W|*fKN`3  
{ u^`eKak"l  
oSavedFile = new RandomAccessFile(sName,"rw"); OJMvn'y  
this.nPos = nPos; R&6n?g6@/V  
oSavedFile.seek(nPos); N4I^.k<-A  
} Bz~ -2#l  
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public synchronized int write(byte[] b,int nStart,int nLen) qTyg~]e9(  
{ KK:N [x  
int n = -1; u$WBc\j  
try{ q<-%L1kc1  
oSavedFile.write(b,nStart,nLen); e{,!|LhpQ  
n = nLen; x Z|&/Ci  
} _ymJ~MK  
catch(IOException e) IYuyj(/!  
{ &g*klt'B  
e.printStackTrace (); j.k@6[R>?  
} V-[2jC{  
^[ET&"  
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return n; pU M&"V  
} VVs{l\$=ZV  
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} e&d3SQ%  
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/* 3"5.eZSOW  
**SiteInfoBean.java a*V9_Px$&  
*/ D^|jZOJ  
package NetFox; p?Z(rCp  
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public class SiteInfoBean { doLkrEm&
 
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private String sSiteURL; //Site's URL Zotz?jVVr  
private String sFilePath; //Saved File's Path uii7b7[w  
private String sFileName; //Saved File's Name YZ0en1ly  
private int nSplitter; //Count of Splited Downloading File *yrnK3  
y $:yz;  
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public SiteInfoBean() Ru:n~77{  
{//nSplitter的缺省值为5 KL "Y!PN:  
//default value of nSplitter is 5 1:_=g#WH  
this("","","",5); USprsaj  
} 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9J?W '8s5  
{ PCtkjd  
sSiteURL= sURL; 3:UA<&=s  
sFilePath = sPath; RYt6=R+f  
sFileName = sName; J=):+F=  
this.nSplitter = nSpiltter; 5lO^;.cS,  
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t')h{2&&!2  
} `Z:3`7c  
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public String getSSiteURL() :.DI_XN`  
{ ovz#  
return sSiteURL; +I&J7ICV0  
} r]0(qg  
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n? ]f@OR  
public void setSSiteURL(String value) !Vb,zQ  
{ C,.-Q"juH  
sSiteURL = value; HM):"  
} y<|)'(  
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public String getSFilePath() AQe!Sqg'  
{ 9Fk4|+OJ  
return sFilePath; %lV@:"G  
} [7RheXO<  
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public void setSFilePath(String value) )=Zsv40O  
{ o_O+u%y  
sFilePath = value; V/+Jc(N  
} d5:tSO  
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public String getSFileName() { UOhVJy  
{ WO
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return sFileName; 8[~~gYl  
} [^M|lf   
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public void setSFileName(String value) VJg,~lQN#t  
{ 7G"7wYc>R  
sFileName = value; ,%Z&*n  
} SW#BZ
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public int getNSplitter() C3)|<E  
{ /VO^5Dnb  
return nSplitter; jN6b*-2  
} U@?6*,b(.  
+2Ql~w@$^l  
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public void setNSplitter(int nCount)
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{ f^?uY8<  
nSplitter = nCount; ;E#\  
} (z2Z)_6L*L  
} d=y0yq{L  
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/* 5oJ Dux }  
**Utility.java .LObOR5J7  
*/ h@@d{{IqT  
package NetFox; *NlpotW,f  
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U CRAw3=  
public class Utility { _q)!B,y-/N  
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public Utility() {zP#woz2Q  
{ 0[)VO[  
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l E^*t`+  
} c#QFG1  
qo_]ZKL44  
//线程睡眠 JKy#j g:#  
public static void sleep(int nSecond) ue6d~8&  
{ VNj@5s  
try{ ]'k[u  
Thread.sleep(nSecond); ?'sXgo.}  
} ru{f]|  
catch(Exception e) mM5|K@0|  
{ -CD\+d "  
e.printStackTrace (); ^i'y6J  
} K%gP5>y*9>  
} rY,PSK/j  
7Ms90oE/c  
//日志 etyCrQ ?U  
public static void log(String sMsg) c@(1:,R  
{ hH`Jb77L  
System.err.println(sMsg); @o#+5P  
} $"8d:N?I[  
kXwi{P3D$  
*Hs*,}M
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public static void log(int sMsg) -=)-sm'  
{ q8sbn  
System.err.println(sMsg); ,[`$JNc  
} *vnXlV4L  
} RtC'v";6  
[M:S`{SbY  
:c7CiP  
/* ?2ItB`<(  
**TestMethod.java ntGq" o  
*/ })[($$f/  
package NetFox; ]1sNmi$T  
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i8~$o:&HT  
public class TestMethod { \H4U8)l  
~HmxEk9  
73 V"s  
public TestMethod() }Hy ~i  
{ ///xx/weblogic60b2_win.exe XoItV  
try{ VVuR+=.&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); VT=K"`EpQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); mxJXL":|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); G{b:i8}l  
fileFetch.start(); )~ z Z'^  
} L.B~ax.|Z  
catch(Exception e){e.printStackTrace ();} ll<mE,  
|0 !I5|<k  
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} )acV-+{  
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public static void main(String[] args) IU!Ht>  
{ kus}WJ  
new TestMethod(); `,Orf ZMb  
} _k2w(ew?  
} f=aIXhiYU  
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