http断点续传简单实现（java)

/* =BW9/fG  
**SiteFileFetch.java iE+6UK  
*/ a^/K?lAB8  
package NetFox; a(!3Afi  
import java.io.*; m9b(3  
import java.net.*; o_3*;}k8  
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public class SiteFileFetch extends Thread { u7~mnl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :5<#X8>d  
long[] nStartPos; //开始位置 HYFN?~G  
long[] nEndPos; //结束位置 g`.{K"N>!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 kpWzMd &RK  
long nFileLength; //文件长度 L B<UC?e  
boolean bFirst = true; //是否第一次取文件 wJ(8}eI  
boolean bStop = false; //停止标志 "_oLe;?$c  
File tmpFile; //文件下载的临时信息 'W+i[Ep5Q  
DataOutputStream output; //输出到文件的输出流 G)4SWu0<t  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \3: L Nt  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6.UKB<sV  
{ 1::LN(`<  
siteInfoBean = bean; K /8qB~J*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J2=*-O:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /6smVz@O  
if(tmpFile.exists ()) A{t"M-<  
{ Fi/jR0]e2  
bFirst = false; [{/$9k-aF?  
read_nPos(); )ZeLaaP  
} Ki63Ox^O  
else TL]
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{ `_0)
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nStartPos = new long[bean.getNSplitter()]; @%%bRY  
nEndPos = new long[bean.getNSplitter()]; e+x*psQ  
} GGp{b>E+ #  
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} y78z>(jV  
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>
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public void run() >waN;&>/  
{ k5g@myb-  
//获得文件长度 .h a`)@MsZ  
//分割文件 M-vC>u3Y  
//实例FileSplitterFetch bbO+%-(X  
//启动FileSplitterFetch线程 dUZ$wbV%h  
//等待子线程返回 iW":DOdi_  
try{ "W3W:vl!  
if(bFirst) &6
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{ q<
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nFileLength = getFileSize(); HmFNE$k  
if(nFileLength == -1) l-Fmn/V  
{ m
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System.err.println("File Length is not known!"); ([1=>Jw"  
} aDXpkG0E  
else if(nFileLength == -2) .byc;9M%  
{ {GAsFnZk  
System.err.println("File is not access!"); eC.w?(RB  
} |iAEDZn  
else e{:86C!d)  
{ \?r$&K]4  
for(int i=0;i<nStartPos.length;i++) AVU7WU{  
{ hl*MUD,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); h<Gypl
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} FF8WTuzB+  
for(int i=0;i<nEndPos.length-1;i++) o}d2N/T  
{ l'W3=,G[?  
nEndPos = nStartPos[i+1]; :l4^iSf  
} 8 H,_vf  
nEndPos[nEndPos.length-1] = nFileLength; vi^z5n  
} >'ie!VW@  
} f(^33k  
^NY+wR5Sn  
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//启动子线程 fmtuFr^a1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yY'gx|\  
for(int i=0;i<nStartPos.length;i++) 3Gj(z:)b  
{ /7.w
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), is64)2F](  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #)Ep(2  
nStartPos,nEndPos,i); PpW A f\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RA!x  
fileSplitterFetch.start(); L,f^mX0<  
} D`1I;Tb#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XSD"/_xD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); FpwlV}:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [SKP|`I>I  
nEndPos = " + nFileLength); $_ST:h&C  
// fileSplitterFetch[nPos.length-1].start(); "vv$%^
 
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//等待子线程结束 -$xKv4  
//int count = 0; D WsCYo  
//是否结束while循环 GH[ U!J  
boolean breakWhile = false; 8[vl3C  
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while(!bStop) 1!K!oY  
{ HJnv'^yn  
write_nPos(); ]!n*V
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Utility.sleep(500); hz&^_G6`  
breakWhile = true; Y+|L3'H  
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for(int i=0;i<nStartPos.length;i++) 9OE_?R0c!  
{ KteZK.+#:  
if(!fileSplitterFetch.bDownOver) L&+% Wd~  
{ 1"mnzbf8*  
breakWhile = false; AaJ,=eQ  
break; %iHyt,0v2  
} [GcA.ABz  
} A}az m>  
if(breakWhile) d,Im&j_Z  
break; !~6'@UYo  
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//count++; m0dFA<5-  
//if(count>4) gt].rwo"  
// siteStop(); }dV9%0s!  
} uJ2C+$=Ul  
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System.err.println("文件下载结束！"); p{\qSPK  
} ]w1BJZa36  
catch(Exception e){e.printStackTrace ();} 4WBoZJ  
} wz*)L (pP  
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//获得文件长度 o3kt0NuF,  
public long getFileSize() G_7ks]u-  
{
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int nFileLength = -1; CDwFVR'_Af  
try{ F[Guy7?O  
URL url = new URL(siteInfoBean.getSSiteURL()); eSQzjR*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EhmUX@k],  
httpConnection.setRequestProperty("User-Agent","NetFox"); s!nSE  
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int responseCode=httpConnection.getResponseCode(); C[Y%=\6'0  
if(responseCode>=400) Z7mGC`>  
{ .(gT+5[  
processErrorCode(responseCode); EU?&  
return -2; //-2 represent access is error i9f7=-[U_  
} `\WcF7  
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String sHeader; /ej/&x15  
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for(int i=1;;i++) O>tC]sm%  
{ {GG~E54&B  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0C"PC:h5  
//Utility.log(in.readLine()); 7Y_fF1-wY  
sHeader=httpConnection.getHeaderFieldKey(i); m=("N  
if(sHeader!=null) Sm*Jysy`  
{ x):k#cu[L  
if(sHeader.equals("Content-Length")) 76u/WC>B  
{ N4Fy8qU;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /eU1(oo&`5  
break; =0!\F~  
} X+'^Sp  
} TCEXa?,L  
else b}}1TnS)  
break; ^R8U-V8:  
} ~_# Y,)S!z  
} {YO%JTQ  
catch(IOException e){e.printStackTrace ();} t^bdi}[  
catch(Exception e){e.printStackTrace ();} XeIUdg4>R  
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Utility.log(nFileLength); I]WeZ,E  
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return nFileLength; c|!A?>O?i  
} zv
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//保存下载信息（文件指针位置） =|WV^0=S'%  
private void write_nPos() 3A}nNHpN  
{ &xiDG=I#  
try{ f2
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output = new DataOutputStream(new FileOutputStream(tmpFile)); 5M\=+5wB  
output.writeInt(nStartPos.length); y T1Qep  
for(int i=0;i<nStartPos.length;i++) 8.;';[  
{ P9tQS"Rs  
// output.writeLong(nPos); /
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output.writeLong(fileSplitterFetch.nStartPos); |au qj2  
output.writeLong(fileSplitterFetch.nEndPos); >kDdWgRQ  
} 5[j!\d}U  
output.close(); eV{FcJha  
} zcD_}t_K  
catch(IOException e){e.printStackTrace ();} tMPXvE  
catch(Exception e){e.printStackTrace ();} L/iVs`qF  
} %Dr4~7=7a  
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:C:N]6_{SZ  
//读取保存的下载信息（文件指针位置） >$S,>d_k`  
private void read_nPos() yzM+28}L<I  
{ eE.5zXU3R  
try{ KZ<
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )T};Q:  
int nCount = input.readInt(); mP$G9R  
nStartPos = new long[nCount]; Jr>S/]"  
nEndPos = new long[nCount]; Vw;ldEdx  
for(int i=0;i<nStartPos.length;i++) V.gY1   
{  \#+2;L  
nStartPos = input.readLong(); 
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nEndPos = input.readLong(); ID)gq_k[8,  
} -C'X4C+  
input.close(); kFIB lPV  
} ng&EGM  
catch(IOException e){e.printStackTrace ();} 8$
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catch(Exception e){e.printStackTrace ();} @gqs4cg{f  
} )D@n?qbG  
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private void processErrorCode(int nErrorCode) g=YiR/O1QN  
{ zyp"*0zUr  
System.err.println("Error Code : " + nErrorCode); 72`/xryY  
} k'I_,Z<,  
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//停止文件下载 (8-lDoW  
public void siteStop() 0-~6} r$  
{ o?O,nD 6  
bStop = true; ^B!?;\4IM  
for(int i=0;i<nStartPos.length;i++) C8W`Oly:]  
fileSplitterFetch.splitterStop(); |Q)w3\S$  
6[h$r/GXh"  
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} J_[[BJ&}x  
} FPUR0myCU  
//负责部分文件的抓取 ,S0~:c:)  
**FileSplitterFetch.java Mm7n?kb6  
*/ %1?V6&  
package NetFox; kdMS"iN8x  
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import java.io.*; x^O2Lj,w\  
import java.net.*; +l?ro[#6&.  
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public class FileSplitterFetch extends Thread { .q9|XDqQc  
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String sURL; //File URL =O'%)Y&  
long nStartPos; //File Snippet Start Position ]|LaMMD  
long nEndPos; //File Snippet End Position hCvLwZ?LF  
int nThreadID; //Thread's ID Ufe  
boolean bDownOver = false; //Downing is over :
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boolean bStop = false; //Stop identical Nx (pJp{S  
FileAccessI fileAccessI = null; //File Access interface Fx99"3`3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9"lW"lG!  
{ b G5  
this.sURL = sURL; x(zZqOed  
this.nStartPos = nStart; pL/.JzB  
this.nEndPos = nEnd; 9PGR#!!F$  
nThreadID = id; Cbg#Yz~/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B{UoNm@  
} sAN:C{  
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public void run() %PdYv _5  
{ MVv^KezD  
while(nStartPos < nEndPos && !bStop) M@X#[w:  
{ |21hY  
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try{ ,Ve@=<  
URL url = new URL(sURL); LP-Q'vb<=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z(X6%p0  
httpConnection.setRequestProperty("User-Agent","NetFox"); z slEUTj)  
String sProperty = "bytes="+nStartPos+"-"; u&_U CJ
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httpConnection.setRequestProperty("RANGE",sProperty); N b[o6AX  
Utility.log(sProperty); ~rX6owBq  
*#^1rKGWK  
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InputStream input = httpConnection.getInputStream(); ^`
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//logResponseHead(httpConnection); ~d `4W<1a  
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byte[] b = new byte[1024]; UYrzsUjg&  
int nRead; yi;t  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &FF. Ddt{  
{ ?[B[ F  
nStartPos += fileAccessI.write(b,0,nRead); 2\tj
eg  
//if(nThreadID == 1) htrj3$q(4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6SO7iFS  
} 6%INNIyAWa  
+*{5ORq=  
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Utility.log("Thread " + nThreadID + " is over!"); [IBk-opap  
bDownOver = true; K
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//nPos = fileAccessI.write (b,0,nRead); G5f57F  
} _:p_#3s$  
catch(Exception e){e.printStackTrace ();} }Y ];ccT  
} tRBK1h  
} l'%R^  
^|;4/=bbs  
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//打印回应的头信息 AHD%6 \$  
public void logResponseHead(HttpURLConnection con) hBE>ea  
{ []!r|R3  
for(int i=1;;i++) "$pgmf2  
{ }/0dfes  
String header=con.getHeaderFieldKey(i); ZKPkx~,U[  
if(header!=null) S)|b%mVwR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =T4w:  
Utility.log(header+" : "+con.getHeaderField(header)); s;WCz  
else X hX'*{3k  
break; $QBUnLOek&  
} z35Rjhj9  
} $-fY8V3[  
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public void splitterStop() AV3,4u  
{ :Ia&,;Gc  
bStop = true; =T}uQ$X  
} J4#]8!A  
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} 8mLU ~P |  
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/* ^(vd8&71  
**FileAccess.java ?+=|{{l  
*//文件访问(定位，写) yvisoZX  
package NetFox; r!,V_a4n  
import java.io.*; f.^w/ GJO/  
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public class FileAccessI implements Serializable{ S`w)b'B!M  
<j3HT"^[D  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C P{h+yCj  
RandomAccessFile oSavedFile; 4:g:$s|SE[  
long nPos; 0*@S-Lj^c  
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public FileAccessI() throws IOException .Kwl8xRg  
{ AI;=k  
this("",0); F &}V65  
} mP[u[|]  
2
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public FileAccessI(String sName,long nPos) throws IOException $7d"9s\$"  
{ $u"$mg7x  
oSavedFile = new RandomAccessFile(sName,"rw"); ??V["o T  
this.nPos = nPos; ".D +# 2Kl  
oSavedFile.seek(nPos); Q*(o;\s  
} ? d\8Q't*  
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public synchronized int write(byte[] b,int nStart,int nLen) IyP].g1"U  
{ X&Lt?e,&  
int n = -1; /Ql}jSKi  
try{ zUqDX{I8  
oSavedFile.write(b,nStart,nLen); )aSkUytg"  
n = nLen; epyfggMT  
} c @
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catch(IOException e) j]&{ @Y  
{ G].KJ5,y  
e.printStackTrace (); 'VEpVo/  
} {hz:[  
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return n; lZ_k307  
} (mlc']F  
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} E:
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/* ] ),'=@  
**SiteInfoBean.java .vMi<U;  
*/ CI{x/ e^(  
package NetFox; GNOC5 E$I  
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<@u6*]  
public class SiteInfoBean { >k|[U[@  
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private String sSiteURL; //Site's URL q?&&:.H"?5  
private String sFilePath; //Saved File's Path 7l3q~dQ  
private String sFileName; //Saved File's Name i;Y^}2   
private int nSplitter; //Count of Splited Downloading File n TG|Isa  
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public SiteInfoBean() YSyW '~!b  
{//nSplitter的缺省值为5 PAkW[;GSDh  
//default value of nSplitter is 5 Lt_]3go  
this("","","",5); l1WVt}  
} >kYyR.p.b  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *en{pR'  
{ 9lv2  
sSiteURL= sURL; x}d\%*B  
sFilePath = sPath; rej[G!  
sFileName = sName; t ,$)PV
 
this.nSplitter = nSpiltter; *Y Ox`z!R  
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} x5ia<V>=d  
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public String getSSiteURL() M_K&x-H0  
{ )f Rh^6  
return sSiteURL; B|v fkX2f  
} h 8s*FI  
t At+5H  
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public void setSSiteURL(String value)
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{ V EzIWNV  
sSiteURL = value; o;fQ,rP%  
} ^-ZqS  
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public String getSFilePath() s/V[tEC*z  
{ t&_lpffv  
return sFilePath; ^^#A9AM  
} vs~*=d27Pf  
,P^"X5$  
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public void setSFilePath(String value) !?{5ET,gtN  
{ N*fN&0r  
sFilePath = value; 
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} VMp6s%m  
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public String getSFileName() eC?N>wHH  
{ 4y'R
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return sFileName; ScEM#9T|  
} -UO$$)Q  
o&=m]hKpQl  
6o!"$IH4  
public void setSFileName(String value) ^IpS 3y  
{ mYCGGwD  
sFileName = value; \ CYu;  
} 4"{q|~&=:$  
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public int getNSplitter() @ o]F~x  
{ c c:xT0Y  
return nSplitter; ~1p f ?  
} 3XIxuQwf  
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public void setNSplitter(int nCount) ||qW'kNWM  
{ ?G@%haqn6  
nSplitter = nCount; ;Bm{_$hf=  
} IcB>Hg5  
} \a<E3 <  
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52
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/* <iMLM<J<w  
**Utility.java .fgoEB,(  
*/ @Z)&
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package NetFox; T"O!  
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public class Utility { @_;6L  
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public Utility() ^pn:SV  
{ s:%>H|-  
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l
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} "YivjHa7H  
s;bqUY?LD  
//线程睡眠 kHJjdgV  
public static void sleep(int nSecond) Gb"PMai  
{ H=0Y4 T@)T  
try{ Rcu/ @j{O  
Thread.sleep(nSecond); FK->|  
} 6uDNqq  
catch(Exception e) d6uL;eR  
{ /Z^+K  
e.printStackTrace (); wDn5|F}i&  
} a}6Wo
=  
} 'E9\V\bi  
HR4^+x  
//日志 YS/4<QA[  
public static void log(String sMsg) C@xh$(y  
{ #U^@)g6  
System.err.println(sMsg); <=WQs2  
} xand%XNv  
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*\emRI>  
public static void log(int sMsg)  $///N+B  
{ UtzW5{  
System.err.println(sMsg); nM@
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} w9vqFtj  
} [-Dx)N  
$cc]pJy"}  
Nx~8]h1(  
/* YqYCW}$  
**TestMethod.java l2xM.v
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*/ *f1MgP*GKF  
package NetFox; tip\vS)  
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<~'\~Zd+  
public class TestMethod { L\pe  
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public TestMethod() TwY]c<t  
{ ///xx/weblogic60b2_win.exe 4~D?F
'o  
try{ d&F8nBIM5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~i(X{^,3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); OXI.>9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oGa8}Vtc  
fileFetch.start(); 8@Pv nOL  
} "+p_{J/P  
catch(Exception e){e.printStackTrace ();} b3W@{je  
<yBZsSj  
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} woQYP,  
3s"
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2}K7(y!?u  
public static void main(String[] args) 0X.pI1jCO  
{ Yz4Q!tL  
new TestMethod(); >IsRd  
} 2]hQ56Yv3  
} 525W; mu{  
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