http断点续传简单实现（java)

/* \=>H6x]q  
**SiteFileFetch.java }^B6yWUN  
*/ 9)VF 1L
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package NetFox; -GLMmZJt  
import java.io.*; pKi&[  
import java.net.*; ?ve#} \  
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public class SiteFileFetch extends Thread { RoAlf+&Qb  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ?.Pg\ur  
long[] nStartPos; //开始位置 =/\:>+p^.y  
long[] nEndPos; //结束位置 QNDHOo>v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Hr$QLtr  
long nFileLength; //文件长度 "Ky; a?Y  
boolean bFirst = true; //是否第一次取文件 h,"4SSL  
boolean bStop = false; //停止标志  ^eoLAL  
File tmpFile; //文件下载的临时信息 tnLAJ+-M  
DataOutputStream output; //输出到文件的输出流 F`9]=T0  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） H:"maS\I  
public SiteFileFetch(SiteInfoBean bean) throws IOException =N 5z@;!  
{ 1!>Jpi0  
siteInfoBean = bean; 2h%z ("3/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @O[5M2|r  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); N]RZbzK_5G  
if(tmpFile.exists ()) =Fdg/X1  
{ ]5%/3P,/  
bFirst = false; }- Wa`t7U  
read_nPos(); "*})3['n  
} ;t+ub8  
else jbR0%X2  
{ E\C9|1)  
nStartPos = new long[bean.getNSplitter()]; K(q-?n`<  
nEndPos = new long[bean.getNSplitter()]; *YlV-C<}W"  
} >$2V%};  
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} VcoOeAKL  
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public void run() RVeEkv[qp  
{ _/O25% l  
//获得文件长度 Ge<nxl<Bd  
//分割文件 @]ao"ui@/  
//实例FileSplitterFetch Onwp-!!.  
//启动FileSplitterFetch线程 S%`0'lzzj  
//等待子线程返回 (T2m"Yi:  
try{ XQS9,Hl  
if(bFirst) Zv#Ll@v  
{ !A%<#Gjt  
nFileLength = getFileSize(); ?@V[#.  
if(nFileLength == -1) t#2(j1  
{ P 3'O/!  
System.err.println("File Length is not known!"); x.q+uU$^  
} )&!&AlLn  
else if(nFileLength == -2) :kGU,>BN  
{ nR`ov1RH  
System.err.println("File is not access!"); ;amXY@RmH  
} w}=5ElB  
else &iV,W4  
{ aE2.L;Tk?  
for(int i=0;i<nStartPos.length;i++) t]-5 ]oI  
{ [p<w._b i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^yOZArc'r  
} 4R\Hpt  
for(int i=0;i<nEndPos.length-1;i++) \eFR(gO+  
{ ,TFIG^Dvq  
nEndPos = nStartPos[i+1]; `]W|8M  
} |6<p(i7  
nEndPos[nEndPos.length-1] = nFileLength; L`24?Y{  
} J_;o|gqX  
} ? YG)I;(  
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//启动子线程 #_u~/jhX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Hhh0T>gi  
for(int i=0;i<nStartPos.length;i++) KRA/MQ^7~U  
{ _F`lq_C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bcYF\@};  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [1u-Q%?#  
nStartPos,nEndPos,i); Gn&4V}F  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9yfJVg  
fileSplitterFetch.start(); q|),`.eh\  
} ^f(@gS}?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V 0rZz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )vSRHE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5D'\b}*lJ}  
nEndPos = " + nFileLength); [W7CXZDd  
// fileSplitterFetch[nPos.length-1].start(); d m`E!R_  
9th,VnD0  
r >nG@A  
//等待子线程结束 gN"7be&J  
//int count = 0; .p(T^ m2A*  
//是否结束while循环 is-7 j7;  
boolean breakWhile = false; *I0T{~  
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while(!bStop) -jiG7OL  
{ OtNd,U.dE  
write_nPos(); 1 9CK+;b  
Utility.sleep(500); H/37)&$E(  
breakWhile = true; J_4!
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for(int i=0;i<nStartPos.length;i++) {Ja!~N;3  
{ 1|jt"Hz  
if(!fileSplitterFetch.bDownOver) ?pd8
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{ :\o {_  
breakWhile = false; VFys.=  
break; H7DJ~z~J  
} mVpMh#zw  
} PGoh1Uu  
if(breakWhile) J G{3EWXR  
break; Kh_Lp$'0uM  
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3(,?S$>  
//count++; rQ qW_t%  
//if(count>4) w {3<{  
// siteStop(); )z28=
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} Ptdpj)oi&Q  
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>  
[
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System.err.println("文件下载结束！"); s|y "WDyx5  
} ZG&>:Si;  
catch(Exception e){e.printStackTrace ();} 71t*%  
} lp^<3o*1  
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//获得文件长度 fNW"+ <W  
public long getFileSize() WL"^>[Vq  
{ jr:7?8cH0L  
int nFileLength = -1; _y} T/I9  
try{ bl&nhI)w  
URL url = new URL(siteInfoBean.getSSiteURL()); G\+L~t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m0a?LY  
httpConnection.setRequestProperty("User-Agent","NetFox"); wG-HF'0L  
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int responseCode=httpConnection.getResponseCode(); z?*w8kU&>  
if(responseCode>=400) N@Uy=?)ZJ  
{ LAS'u"c|  
processErrorCode(responseCode); 2so!  
return -2; //-2 represent access is error !`Hd-&}bYz  
} 6"&6`f  
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String sHeader; :Ra,Eu  
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for(int i=1;;i++) >8#X;0\Kj  
{ SPY|K  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ssou  
//Utility.log(in.readLine()); dQA'($  
sHeader=httpConnection.getHeaderFieldKey(i); 9CWezI+  
if(sHeader!=null) )9"_J9G  
{ r\-uJ~8N  
if(sHeader.equals("Content-Length")) b((M)Gz  
{ Gsq00j &<Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _C*fs<#  
break; @] DVD  
} }o?APvd  
} q(.sq12<<W  
else eoG$.M"  
break; I%j|D#qY:T  
} eo?;`7  
} DN-+o
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catch(IOException e){e.printStackTrace ();} 2j}\3Pi  
catch(Exception e){e.printStackTrace ();} %4,O 2\0?&  
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Utility.log(nFileLength); 9CWF{"  
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return nFileLength; $!-c-0ub  
} Gi?/C&1T  
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//保存下载信息（文件指针位置） v4`"1Ss,K  
private void write_nPos() AQ,' 6F9  
{ '$ =>  
try{ Mh:L$f0A%O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); l3Q(TH~I  
output.writeInt(nStartPos.length); #*K}IBz  
for(int i=0;i<nStartPos.length;i++) 8<pzb}xK  
{ >,$_| C  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); z<U-#k7nz  
output.writeLong(fileSplitterFetch.nEndPos); ORHp$Un~)  
} ?mFv0_!O
 
output.close(); "4+&-ms  
} _VRpI)mu  
catch(IOException e){e.printStackTrace ();} Vt %bI0#  
catch(Exception e){e.printStackTrace ();} 5HkKurab  
} 5 ZGNz1)?V  
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}@'$b<!B  
//读取保存的下载信息（文件指针位置） ]6(N@RC  
private void read_nPos() .f%fHj  
{ K1"*.\?F  
try{ ?(Dq?-.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); VM GS[qrG  
int nCount = input.readInt(); -D  
nStartPos = new long[nCount]; !;Yg/'vD-  
nEndPos = new long[nCount]; cl=EA6P\X  
for(int i=0;i<nStartPos.length;i++) 
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{ \r^qL^  
nStartPos = input.readLong(); JQ8fdP A  
nEndPos = input.readLong(); m? J0i>H  
} |:q=T ~x  
input.close(); e6R}0w~G  
} C*)3e*T
*  
catch(IOException e){e.printStackTrace ();} y&q*maa[  
catch(Exception e){e.printStackTrace ();} o
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} sJ;g$TB  
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private void processErrorCode(int nErrorCode) ;4R$g5-4X  
{ l&O
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System.err.println("Error Code : " + nErrorCode); TJ_$vI  
} QRc{vUR&  
@r/#-?W  
A!s`[2 Z  
//停止文件下载 \r;#g{ _  
public void siteStop() >kj`7GA  
{ jaTh^L  
bStop = true; cs,N <|  
for(int i=0;i<nStartPos.length;i++) gf#{k2r  
fileSplitterFetch.splitterStop(); >Wm`v.-  
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} FcR=v0),  
} [-65PC4aN  
//负责部分文件的抓取 ~P*6ozSYpY  
**FileSplitterFetch.java ~("5yG  
*/ KyVQh8  
package NetFox; {C 6=[  
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import java.io.*; oX#Q<2z*  
import java.net.*; q-[@$9AS  
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public class FileSplitterFetch extends Thread { yh Yb'GK  
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)
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String sURL; //File URL 7]U"Z*  
long nStartPos; //File Snippet Start Position "Q}#^h]F  
long nEndPos; //File Snippet End Position 54gBJEhg  
int nThreadID; //Thread's ID nno}e/zqf  
boolean bDownOver = false; //Downing is over (|[2J3ZET  
boolean bStop = false; //Stop identical @oNH@a j%  
FileAccessI fileAccessI = null; //File Access interface Od)Uv1  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +DW~BS3  
{ #+:9T/*>0  
this.sURL = sURL; T}Km?d  
this.nStartPos = nStart; lW+\j3?Z$  
this.nEndPos = nEnd; )#BMTKA^  
nThreadID = id; :=}US}H$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 nG,A@/N  
} g-Mj.owu=  
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public void run() bV(Y`g  
{ G<At_YS  
while(nStartPos < nEndPos && !bStop) @E;=*9ek{u  
{ 1{r3#MVL  
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try{ E=jNi  
URL url = new URL(sURL); t
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H2&@shOOQJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); \.C+ue  
String sProperty = "bytes="+nStartPos+"-"; G^~k)6v=m  
httpConnection.setRequestProperty("RANGE",sProperty); x^HGVWw_  
Utility.log(sProperty); SFB~ ->db  
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InputStream input = httpConnection.getInputStream(); MC?,UDNd%  
//logResponseHead(httpConnection); gcE|#1>  
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byte[] b = new byte[1024]; {J{+FFsr(  
int nRead; V[{6e  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) CpA|4'#  
{ {\
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nStartPos += fileAccessI.write(b,0,nRead); bHPYp5UwN  
//if(nThreadID == 1) *}
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @E^~$-J5j  
} Qt iDTr  
:?k>HQe  
2>|dF~"  
Utility.log("Thread " + nThreadID + " is over!"); u\E?Y[1  
bDownOver = true; )'Oh`$M  
//nPos = fileAccessI.write (b,0,nRead); XxT#X3D/,"  
} k>F'ypm  
catch(Exception e){e.printStackTrace ();} 6o |kIBte-  
} g'pK  
} IM:=@a{  
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//打印回应的头信息 E'v_#FLvR  
public void logResponseHead(HttpURLConnection con) #hW;Ju73  
{ G %
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for(int i=1;;i++) l/BLUl~z  
{ J cg,#@  
String header=con.getHeaderFieldKey(i); B||*.`3gN  
if(header!=null) Scp7X7{N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); BS /G("oZ[  
Utility.log(header+" : "+con.getHeaderField(header)); +~'865{  
else p%iGc<vHX  
break; unshH<  
} A54N\x,  
} 2]I4M[|&z  
flk=>
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@'YS1N<  
public void splitterStop() 8 ![|F:  
{ <!L>Exh&r  
bStop = true; ^w(p8G_-w  
} gfX\CSGy  
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} i7]4W  
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/* 4?0vso*X<:  
**FileAccess.java U2{ dN>  
*//文件访问(定位，写) >^%7@i:@U  
package NetFox; q/4YS0CqE  
import java.io.*; aT_&x@x  
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public class FileAccessI implements Serializable{ `^bgUmJ~  
.^N/peUq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !g Z67  
RandomAccessFile oSavedFile; /3A^I{e74  
long nPos; OTMJ6)n7  
}tsYJlh5  
${+ @gJ+S  
public FileAccessI() throws IOException EPS={w$'s  
{ )A!>=2M`  
this("",0); yMyE s8  
} }-ftyl7  
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public FileAccessI(String sName,long nPos) throws IOException j*F`"df  
{ cU ?0(z7  
oSavedFile = new RandomAccessFile(sName,"rw"); f>aEkh6u9  
this.nPos = nPos; )\sc83L  
oSavedFile.seek(nPos); R16'?,  
} 5nv<^>[J  
(:._"jp]  
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public synchronized int write(byte[] b,int nStart,int nLen) 2rmSo&3@s  
{ ObLly%|i  
int n = -1; .jS~By|r  
try{ \zieyE  
oSavedFile.write(b,nStart,nLen); 8#(Q_  
n = nLen; V+Cwzc^j  
} /DQc&.jK  
catch(IOException e) M%1}/!J3  
{ Q>/C*@  
e.printStackTrace (); A/s>PhxV  
} I?"q/Ub~h  
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return n; (7XCA,KTGI  
}
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} /rq VB|M  
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/* nA P.^_K  
**SiteInfoBean.java <@}I0  
*/ @fs`=lL/  
package NetFox; [[>wB[w  
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public class SiteInfoBean { w;k):;$  
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private String sSiteURL; //Site's URL }-~X4u#  
private String sFilePath; //Saved File's Path F;gx%[$GX  
private String sFileName; //Saved File's Name e&>;*$)  
private int nSplitter; //Count of Splited Downloading File Jrg2/ee,*  
qHNE8\9  
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public SiteInfoBean() AZa6Cw  
{//nSplitter的缺省值为5 k]5Bykf`Ky  
//default value of nSplitter is 5 A|L8P  
this("","","",5); iXjo[Rz^C  
} usEwm,b)  
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pGf@z:^{*-  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) uL3Eq>~x  
{ )RO<o O  
sSiteURL= sURL; UB 6mqjPK  
sFilePath = sPath; n|b5? 3  
sFileName = sName; ZO4*sIw%  
this.nSplitter = nSpiltter; 6oLwfTy  
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K4]
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} 6B@CurgB  
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9lGOWRxR)  
public String getSSiteURL() Qu}W/j|3  
{ ax{ ;:fW  
return sSiteURL; !-N6l6N  
} FBpH21|/y  
INkD=tX  
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public void setSSiteURL(String value) n>A98NQ  
{  )$`wIp  
sSiteURL = value; $<^u^q37u  
} 'Hi: 2Wh  
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public String getSFilePath() {X[ HCfJd  
{ i
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return sFilePath; HAv{R!*  
} $Bj;D=d@V  
!'j?.F$}  
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public void setSFilePath(String value) Q>R>R*1.
j  
{ 4<cz--g  
sFilePath = value; 0H0-U'l  
} IBQ@{QB  
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public String getSFileName() {5d9$v7k4  
{ M
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return sFileName; FJ %  
} zfc3)7  
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public void setSFileName(String value) ,(.MmP`  
{ H-3Eo
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sFileName = value; O/.Uh`T`6  
}
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h.!}3\Y  
public int getNSplitter() DhX#E&  
{ ?%VI{[y#>  
return nSplitter; -F=v6N{  
} U,+[5sbo  
]$p{I)d&  
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public void setNSplitter(int nCount) `xz<>g9e  
{ r1<F  
nSplitter = nCount; Y3h/~bM%
 
} Qj3a_p$)P  
} etd&..]J  
,=aJVb=C  
7HVZZ!>~  
/* 9}c8Xt^&  
**Utility.java .TE?KI 
  
*/ ;SwMu@tg  
package NetFox; 2o#,kGd  
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public class Utility { ,+g&o^T  
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public Utility() e(NLX`  
{ hky;CD~$  
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} DI`%zLDcY  
/)xlJUq  
//线程睡眠 ZhNdB  
public static void sleep(int nSecond) Dfd-^N!  
{ `MEYd U1  
try{ 1
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Thread.sleep(nSecond); cEe?*\G  
} `z0{S!  
catch(Exception e) )HD`O~M>  
{ AH4EtZC=W  
e.printStackTrace (); ;.wX@  
} W5/0`[4  
} AF43$6KZP$  
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//日志  KluA  
public static void log(String sMsg) 9'x)M?{8  
{
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System.err.println(sMsg); aZKOY  
} Z?J:$of*  
CC;! <km  
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public static void log(int sMsg) "4H8A=  
{ hh~n#7w~IR  
System.err.println(sMsg); r}u%#G+K,  
} +%N KQ'49I  
} {FN;'Uc  
>)_ojDO  
CK_(b"  
/* d7cg&9+  
**TestMethod.java Px5t,5xT8  
*/ fag^7rz  
package NetFox; XT,#g-oi  
wA`"\MWm  
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public class TestMethod { WxbsD S;  
Gjz[1d  
zH=!*[d8  
public TestMethod() O3n_N6| q  
{ ///xx/weblogic60b2_win.exe 4gdY`}8b^}  
try{ o2-@o= F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9umGIQHnil  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); f>$h@/-*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]WJfgN4  
fileFetch.start(); 'f/Lv@]a  
} kqvow3u  
catch(Exception e){e.printStackTrace ();} Uz%Z&K  
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} 1u]P4Gf=  
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e=/&(
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public static void main(String[] args) ,/&Zw01dGN  
{ SQE[m9v  
new TestMethod(); &[?CTZ  
} +rNkN:/L  
} ID}
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