http断点续传简单实现（java)

/* {;^GKb+  
**SiteFileFetch.java Dwa.ZY}-  
*/ h{/lW#[  
package NetFox; R\Of ,  
import java.io.*; j9g0k<eg  
import java.net.*; 4V7=VZ,@3  
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public class SiteFileFetch extends Thread { {osadXdC  
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SiteInfoBean siteInfoBean = null; //文件信息Bean
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long[] nStartPos; //开始位置 O3En+m~3n)  
long[] nEndPos; //结束位置 F [S'l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Sh;Z\nj  
long nFileLength; //文件长度 |
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boolean bFirst = true; //是否第一次取文件 W@p27Tiq  
boolean bStop = false; //停止标志 V:h3F7  
File tmpFile; //文件下载的临时信息 d8N4@3CkL  
DataOutputStream output; //输出到文件的输出流 c-`izn]  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `6FH@" |I  
public SiteFileFetch(SiteInfoBean bean) throws IOException _M)J{ {?:  
{ * am
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siteInfoBean = bean; wCw_aXqq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z *~rd2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5{\;7(  
if(tmpFile.exists ()) >goG\y  
{ yo]8QO]97  
bFirst = false; Zd~Q@+sH  
read_nPos(); UYkuz  
} `(&GLv[i^2  
else  E-L>.tD  
{ r[4dGt  
nStartPos = new long[bean.getNSplitter()]; <qjolMO`  
nEndPos = new long[bean.getNSplitter()]; iXD=_^^o .  
} :IRQouTf:,  
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} :~LOw}N!aQ  
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public void run() )vy_m_f&  
{ #)z7&nD  
//获得文件长度 I!Uj~jV  
//分割文件 M6:$ 0(r  
//实例FileSplitterFetch aB)G!Rm&  
//启动FileSplitterFetch线程 ucX!6)Op  
//等待子线程返回 TykY>cl   
try{ A}MF>.!}C  
if(bFirst) ,Lr}P  
{ H':0  
nFileLength = getFileSize(); pL`)^BJ  
if(nFileLength == -1) n+w$'l  
{ ]:Sb#=,!&!  
System.err.println("File Length is not known!"); .(X!*J]G  
} cW?~]E'<  
else if(nFileLength == -2) z]n&,q,5g  
{ "fWm{;  
System.err.println("File is not access!"); BBHoD:l  
} k?`Q
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else ?jHu,  
{ ]X<L~s_*  
for(int i=0;i<nStartPos.length;i++) >IEc
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{ i$dF0.}Q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %)PQomn?  
} KK41I8Mw  
for(int i=0;i<nEndPos.length-1;i++) ?oulQR6:  
{ 7U`8W\-  
nEndPos = nStartPos[i+1]; u!9bhL`  
} N7}yU~j^  
nEndPos[nEndPos.length-1] = nFileLength; A}z1~Z+  
} [K#pU:lTH  
} t2#zQ[~X!  
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//启动子线程 {14sI*b16  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0=c:O  
for(int i=0;i<nStartPos.length;i++) ^9 {r2d&c  
{ ^ Mw=!n[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A]AM|2
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #u$Z/,  
nStartPos,nEndPos,i); xqLIs:*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?PDrj/: *  
fileSplitterFetch.start(); &E$:^a4d  
} /<it2=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u,),kj<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `]m/za%7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", HQtUNtZ  
nEndPos = " + nFileLength); 8b:\@]g$  
// fileSplitterFetch[nPos.length-1].start(); O:Ob{k  
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//等待子线程结束 qwDoYyyu  
//int count = 0; \X0wr%I  
//是否结束while循环 k ks ?S',  
boolean breakWhile = false; `%Uz0hF  
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while(!bStop) ~n`G>Oe3  
{ ,Z p9,nf  
write_nPos(); X]AbBzy  
Utility.sleep(500); TM1J1GU  
breakWhile = true; }Q%fY&#(bp  
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for(int i=0;i<nStartPos.length;i++) TLiA>`r=  
{ 3+| {O  
if(!fileSplitterFetch.bDownOver) I0]"o#LjT  
{ PmT,*C`/X  
breakWhile = false; Il,^/qvIY  
break; tx
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} 'P5|[du+  
} )./.rtP|4  
if(breakWhile) ?{M!syD<  
break; aok,qn'j  
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//count++; B)`^/^7  
//if(count>4) ewb/Z[4  
// siteStop(); x#s=eeP1  
} IRW%*W#  
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System.err.println("文件下载结束！"); 9AROvq|#  
} WxFrqUz  
catch(Exception e){e.printStackTrace ();} %<Q?|}  
} a>{b'X^LV  
2!^[x~t  
q$=EUB"C  
//获得文件长度 }uE8o"q  
public long getFileSize() uY;2tZldf=  
{ ,3{z_Rax-  
int nFileLength = -1; wbaXRvg  
try{ .h8%zB#|i  
URL url = new URL(siteInfoBean.getSSiteURL()); L('G1J}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Sh_=dzM  
httpConnection.setRequestProperty("User-Agent","NetFox"); SEc3`y;j%  
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int responseCode=httpConnection.getResponseCode(); Y+#e| x  
if(responseCode>=400) >Rbgg1^]5  
{ Svmyg]  
processErrorCode(responseCode); [[PUK{P0  
return -2; //-2 represent access is error G'<J8;B* t  
} |WB<yA1  
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String sHeader; .wD>0Ig  
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for(int i=1;;i++) }V3p <  
{ @awaN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,0#5k
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//Utility.log(in.readLine()); S< <xlW  
sHeader=httpConnection.getHeaderFieldKey(i); ~7!J/LHg  
if(sHeader!=null) )T:{(v7 d`  
{ B
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if(sHeader.equals("Content-Length")) ! G%LYHx  
{ W9?Yzl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SPIYB/C  
break; ~$f+]7  
} hltH{4  
} buRXzSR  
else \K)"@gdW  
break; 8 F'i5i  
} :YB:)wV,P  
} &tKs t,UR8  
catch(IOException e){e.printStackTrace ();} n]x4twZ  
catch(Exception e){e.printStackTrace ();} M%:ACLYP  
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Utility.log(nFileLength); >#R<*?*D}  
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return nFileLength; Q/iaxY#  
} S,vrz!'>A  
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//保存下载信息（文件指针位置） m4ovppC  
private void write_nPos() sRo%=7Z  
{ =4y
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try{ #HB]qa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); SMgf(N3]  
output.writeInt(nStartPos.length); FgRlxz  
for(int i=0;i<nStartPos.length;i++) GFx>xQk  
{ p0uQ>[NV0  
// output.writeLong(nPos); f6^H Q1SSt  
output.writeLong(fileSplitterFetch.nStartPos); Ol"p^sqwj  
output.writeLong(fileSplitterFetch.nEndPos); ,a< !d  
} PR~ho&!  
output.close(); 1d|+7  
} %|o4 U0c  
catch(IOException e){e.printStackTrace ();} Z KnEg2a  
catch(Exception e){e.printStackTrace ();} " 9 h]P^  
} ]gkI:scPA  
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//读取保存的下载信息（文件指针位置） .5|wy<  
private void read_nPos() $~50M5&K#  
{ >&e|ins^N  
try{ jRXByi=9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Fc7mAV=  
int nCount = input.readInt(); Am!$\T%2  
nStartPos = new long[nCount]; `*8p T  
nEndPos = new long[nCount]; xgL*O>l)  
for(int i=0;i<nStartPos.length;i++) UbJ_'>hK6  
{ G*mk 19Z  
nStartPos = input.readLong(); }Hr
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nEndPos = input.readLong(); E*.D_F  
} XJC|6"n  
input.close(); mE%H5&VSI  
} lycY1lK  
catch(IOException e){e.printStackTrace ();} $=TFTSO  
catch(Exception e){e.printStackTrace ();} <:2El9l!  
} L/"XIMI*Xg  
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private void processErrorCode(int nErrorCode) tqAh&TW3+  
{ 41^+T<+  
System.err.println("Error Code : " + nErrorCode); ((N<2G)  
} pz6fL=Xd  
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//停止文件下载 V?t^ J7{'  
public void siteStop() a"0Xam  
{ PiMh]  0  
bStop = true; OSK3X Qc  
for(int i=0;i<nStartPos.length;i++) weU'3nNN  
fileSplitterFetch.splitterStop(); ,Za!  
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} Z[RE|l{  
} ZC@ 33Q(  
//负责部分文件的抓取 !0CC&8C`  
**FileSplitterFetch.java c]v$C&FX  
*/ Cz-eiPlq  
package NetFox; U ]`SM6  
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import java.io.*; 9i*t3W71]  
import java.net.*; WId"2W3M  
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public class FileSplitterFetch extends Thread { KaNi'=nW  
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String sURL; //File URL R?b3G4~  
long nStartPos; //File Snippet Start Position 'c*Q/C;  
long nEndPos; //File Snippet End Position {Iy<iV  
int nThreadID; //Thread's ID LuM:dJ  
boolean bDownOver = false; //Downing is over RSC^R}a5  
boolean bStop = false; //Stop identical w=Ac/12  
FileAccessI fileAccessI = null; //File Access interface 9E5Ec~l   
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0+L:+S  
{ sG[v vm  
this.sURL = sURL; {}kE=L5  
this.nStartPos = nStart; SR)G!9z_/  
this.nEndPos = nEnd; }^U7NZn<"  
nThreadID = id; I(tMw6C$:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -c|dTZ8D)8  
} _&)^a)Nu  
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public void run() "HX,RJ @^K  
{ E w#UlA:"v  
while(nStartPos < nEndPos && !bStop) wCw-EGLR  
{ ecaEWIOG  
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try{ +a1Or  
URL url = new URL(sURL); TgMa!Vz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U4)x"s[CP  
httpConnection.setRequestProperty("User-Agent","NetFox"); VBnD:w"z  
String sProperty = "bytes="+nStartPos+"-"; W%&t[_21  
httpConnection.setRequestProperty("RANGE",sProperty); }p,#rOX:A  
Utility.log(sProperty); r&  
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InputStream input = httpConnection.getInputStream(); cHo@F!{o=  
//logResponseHead(httpConnection); &U*MLf83`  
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byte[] b = new byte[1024]; X!H[/b:
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int nRead; 8xf]zM"Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^97u0K3$  
{ t&|M@Ouet  
nStartPos += fileAccessI.write(b,0,nRead); 5rp,xk!  
//if(nThreadID == 1) zplAH!s5''  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ByyvRc,v  
} m\*;Fx  
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Utility.log("Thread " + nThreadID + " is over!"); Pgug!![  
bDownOver = true; !s^[|2D_U  
//nPos = fileAccessI.write (b,0,nRead); B:mtl?69g  
} Dh+<|6mx  
catch(Exception e){e.printStackTrace ();} kPRG^Ox8e  
} .+3~ w  
} >wSrllmj@  
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//打印回应的头信息 ,I|3.4z  
public void logResponseHead(HttpURLConnection con) 
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{ 9U]3B)h%m  
for(int i=1;;i++) cQzUR^oq,  
{ . E8Gj'yO  
String header=con.getHeaderFieldKey(i); x*'2%3C~  
if(header!=null) g9~QNA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +HDfEo T  
Utility.log(header+" : "+con.getHeaderField(header)); .@KI,_X6,  
else kR0
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break; } "QL"%  
} "J(T?|t  
} %ztv.K(8  
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public void splitterStop() F+<e9[  
{ 99GK6}~TGm  
bStop = true; MV.&GUez{  
} fK/|0@B8  
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} >PS`;S!(  
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/* 'ZFbyt Q2  
**FileAccess.java P. Kfoos  
*//文件访问(定位，写) A$jf#,  
package NetFox; [QDM_n  
import java.io.*; 6s.>5}M!  
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public class FileAccessI implements Serializable{ >F5E^DY  

' e:rL.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 GZ1c~uAu  
RandomAccessFile oSavedFile; ZH)thd9^b  
long nPos; O77^.B  
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public FileAccessI() throws IOException ' OXL'_Xl  
{ %CV.xDE8  
this("",0); uskJ(!  
} /k.?x]Ab  
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public FileAccessI(String sName,long nPos) throws IOException @(CJT-Ak  
{ 6<o2 0(?  
oSavedFile = new RandomAccessFile(sName,"rw"); #BW:*$>}  
this.nPos = nPos; $O^"OQ_@  
oSavedFile.seek(nPos); ==npFjB  
} -\&b&;_  
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public synchronized int write(byte[] b,int nStart,int nLen) 3Ct)5J  
{ :yFmCLZaQ  
int n = -1; n{"e8vQx
 
try{ =`g@6S  
oSavedFile.write(b,nStart,nLen); ]$)U~)T iW  
n = nLen; bL2b^UB~%  
} H`OJN.  
catch(IOException e) `s8!zy+  
{ hQ}y(2A.XI  
e.printStackTrace (); \h
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} 5Ve T8/7Q  
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return n; 4tlLh`-8  
} @DuSii#.S  
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+
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} &Fh#otH_  
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/* lbm ,#  
**SiteInfoBean.java g|<$\}  
*/ <K
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package NetFox; HFW8x9Cc  
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public class SiteInfoBean { bG/[mZpRT  
.&rL>A2U  
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private String sSiteURL; //Site's URL ~IQw?a.E  
private String sFilePath; //Saved File's Path B qcFbY  
private String sFileName; //Saved File's Name yZY.B {  
private int nSplitter; //Count of Splited Downloading File QygbfW6u  
Jj7he(!_1  
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public SiteInfoBean() <CN+VXF  
{//nSplitter的缺省值为5 B8NMo5a  
//default value of nSplitter is 5 G$E+qk nJL  
this("","","",5); 6$ ag<  
} VH6J @m  
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6.
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lH"4"r  
{ JQH>{OB  
sSiteURL= sURL; 7 |Q;E|=-Y  
sFilePath = sPath; !1xX)XD4y  
sFileName = sName; T*qSk!  
this.nSplitter = nSpiltter; !c;BOCqa  
,m1F<Pdts  
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} -}9>#<v  
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public String getSSiteURL() @]@6(To  
{ tV
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return sSiteURL; hYSf;cG}A  
} >rid3~  
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MT{ovDA].  
public void setSSiteURL(String value) hv#|dI=kZR  
{ lFbf9s:$B  
sSiteURL = value; ';3#t(J;  
} s}bv o  
48RSuH  
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public String getSFilePath() 67A g.f6-  
{ maVfLVx-  
return sFilePath; ;Miag'7  
} -;j '=?  
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public void setSFilePath(String value) h Nx#x  
{ MP$9W)  
sFilePath = value; NM4b]>  
} CZw]@2/JuQ  
k%%0"+y#a  
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public String getSFileName() $$e"[g  
{ Q|(G -  
return sFileName; ]? %*3I  
} 5aJd:36I  
#}S<O_  
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public void setSFileName(String value) q}cm"lO$  
{ GGez!?E%  
sFileName = value; cjwc:3 CM  
} T7?cnK"  
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public int getNSplitter() u#nM_UJe  
{ X ;Cl8  
return nSplitter; 'q\[aKEX=  
} h?P- :E  
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public void setNSplitter(int nCount) GD0Q`gWNe  
{ OBL2W\{  
nSplitter = nCount; 8c%_R23  
} yR1v3D4E  
} ]h%~'8g,  
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7mA:~-.u  
/* ?,w9e|  
**Utility.java FK~*X
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*/ om2)Cd9~7  
package NetFox; ZKt`>KZ  
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public class Utility { S|r,RBeZ  
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public Utility() .4[M7)  
{ eI1C0Uz1  
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jIck!  
} 6"yIk4u:  
6#kmV  
//线程睡眠 1*?L>@Wdy  
public static void sleep(int nSecond) q9(Z9$a(\  
{ ht2J, 1t  
try{ xM?tdQ~VHY  
Thread.sleep(nSecond); <Aqo[']  
} ny1Dg$ui2  
catch(Exception e) rPK1#  
{ -nqq;|%  
e.printStackTrace (); v;(k7
 
} {_ {zs!r  
} Y%^qt]u.8  
S|]\q-qA&  
//日志 dH)\zCt  
public static void log(String sMsg) *iJ>@vew  
{ 6*:U1{Gl)  
System.err.println(sMsg); HjY! ]!4p  
} p8MN>pLP%  
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kOQ!]-;  
public static void log(int sMsg) |eK^Yhy
m  
{ U% OlYP$g  
System.err.println(sMsg); =g$%jM>35  
} 2E0oLl[  
} iN
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/L=Y8tDt
 
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/* o,'Fz?[T%  
**TestMethod.java p. KT=dZT  
*/ JZ/T:Hsh4  
package NetFox; QObHW[:F  
L=&}s[5  
3
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public class TestMethod { 1cD  
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public TestMethod() meZZQ:eSl  
{ ///xx/weblogic60b2_win.exe ,,;vG6^a  
try{ |CPyCM$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ne%(`XY{Q]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7=a e^GKo  
SiteFileFetch fileFetch = new SiteFileFetch(bean); XO}SPf-  
fileFetch.start(); Wm/0Pi  
} p5J!j I=  
catch(Exception e){e.printStackTrace ();} sLf~o"yb  
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} s?PB ]Tr
 
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public static void main(String[] args) _z>%h>L|g  
{ DS;.)P"  
new TestMethod(); &U\//  
} fvj  
} pW_mS|  
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