http断点续传简单实现（java)

/* ^N={4'G)  
**SiteFileFetch.java \}b2oiY  
*/ qf0pi&q  
package NetFox; agUdI_'~@9  
import java.io.*; Vh\_Ko\V5  
import java.net.*; S\:^#Yi`  
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public class SiteFileFetch extends Thread { Bq8#'K2i
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SiteInfoBean siteInfoBean = null; //文件信息Bean I
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long[] nStartPos; //开始位置 )O[8 D  
long[] nEndPos; //结束位置 e)e(f"t6Q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >fC&bab  
long nFileLength; //文件长度 E^-c
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boolean bFirst = true; //是否第一次取文件 [piK"N  
boolean bStop = false; //停止标志 Wg}KQ6 6  
File tmpFile; //文件下载的临时信息 31G:[;g  
DataOutputStream output; //输出到文件的输出流 ko}& X=  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） RE t&QP  
public SiteFileFetch(SiteInfoBean bean) throws IOException $1])>m_ct  
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siteInfoBean = bean; dy6zrgxygP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y][12{I{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &kb~N-  
if(tmpFile.exists ()) V[.{cY?6  
{ #eJfwc1JY  
bFirst = false; sV"tN2W@  
read_nPos(); 2VV>?s  
} E3wpC#[Q1  
else 1EV bGe%b  
{ ,3?=W/Um4  
nStartPos = new long[bean.getNSplitter()]; ^JY {<  
nEndPos = new long[bean.getNSplitter()]; ' #K@%P  
} _f!ko<52  
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} s4Ja y!A  
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public void run() >"/TiQt  
{ #.Dl1L/  
//获得文件长度 ^6Aa^|  
//分割文件 ^?e[$}  
//实例FileSplitterFetch 2[Bbdg[O  
//启动FileSplitterFetch线程 /[6wm1?!  
//等待子线程返回 Ls2O
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try{ oN}\bK  
if(bFirst) MQ =x:p{  
{ 1'~+.92Y  
nFileLength = getFileSize(); g(P7CX+y  
if(nFileLength == -1) pKLcg"{[F  
{ iB0r+IbR  
System.err.println("File Length is not known!"); }'<Z&NW6  
} z\v  
else if(nFileLength == -2) :/6:&7s  
{ @IL@|Srs8  
System.err.println("File is not access!"); ,8*A#cT B  
} 0^{Tq0Ri[  
else B)/&xQu  
{ dZ|bw0~_!  
for(int i=0;i<nStartPos.length;i++) 0of:tZU  
{ d)48m}[:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,JH*l:
7  
} e`+  
for(int i=0;i<nEndPos.length-1;i++) a3A-N] ;f  
{ -)J*(7F(6^  
nEndPos = nStartPos[i+1]; p!DdX  
} W[QgddR  
nEndPos[nEndPos.length-1] = nFileLength; {{A=^rr%C  
} h9Sf  
} UHY)+6qt]  
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//启动子线程 Q]/g=Nn ^~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,9|7{j|u  
for(int i=0;i<nStartPos.length;i++) SFWS<H(IN  
{ 2aivc,m{r  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %_]O|(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -{3^~vW|<  
nStartPos,nEndPos,i); @
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {w>ofyqfp&  
fileSplitterFetch.start(); Uwiy@T Z  
} bAY>o
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <O9WCl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9Lt3^MKa"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w#(E+s~}  
nEndPos = " + nFileLength); Rv*x'w ==  
// fileSplitterFetch[nPos.length-1].start(); cCtd\/ \  
"gpfD-BX  
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//等待子线程结束 |b Z 58{}  
//int count = 0; k<*1mS8  
//是否结束while循环 @ceL9#:uc  
boolean breakWhile = false; #z}IW(u<  
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while(!bStop) D//Ts`}+n  
{ .dBW{|gN  
write_nPos(); XK l3B=h  
Utility.sleep(500); h7\EN  
breakWhile = true; 6l?KX  
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for(int i=0;i<nStartPos.length;i++) xJzO?a'  
{ ~o;*{ Q  
if(!fileSplitterFetch.bDownOver) 5[qx5|O  
{ ]s_BOt  
breakWhile = false; n]JfdI  
break; )vur$RX  
} +QrbW  
} A^7Y%  
if(breakWhile) }WkR-5N  
break; U}`HN*Q.q  
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rUF= uO(  
//count++; r#.\5aQt  
//if(count>4) tdRnRoB  
// siteStop(); 0j~C6vp  
} T xwZ3E  
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^  
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System.err.println("文件下载结束！");
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} w0t||qj^>"  
catch(Exception e){e.printStackTrace ();}  #`2*V  
} T%:W6fH7  
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//获得文件长度 =:=uV0jX\  
public long getFileSize() {7X80KI  
{ ugt|'i  
int nFileLength = -1; RV:%^=V-  
try{ 6d3-GMUQ  
URL url = new URL(siteInfoBean.getSSiteURL()); rOy-6og
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ) crhF9!4  
httpConnection.setRequestProperty("User-Agent","NetFox"); co%ttH\ n  
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int responseCode=httpConnection.getResponseCode(); h=~TgTv  
if(responseCode>=400) }%9A+w}o  
{ j!P]xl0vOZ  
processErrorCode(responseCode); ebS>_jD  
return -2; //-2 represent access is error V"@]PI pr  
} M1T)e9k=x  
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String sHeader;  + >oA@z  
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for(int i=1;;i++) bEE'50D  
{ RscU=oaKi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n_51-^*z  
//Utility.log(in.readLine()); }Z_w8+BZ  
sHeader=httpConnection.getHeaderFieldKey(i); $;dSM<r  
if(sHeader!=null) ZLJf
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{ /t083  
if(sHeader.equals("Content-Length")) 'lym^^MjL+  
{ {? jr  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Vx^+Z,y&QP  
break; iC`K$LY4W  
} nDSmr  
} c?{&=,u2  
else Bp`?inKBOd  
break; &!#a^d+` 0  
} 1#9Q1@'OS  
} dhW)<  
catch(IOException e){e.printStackTrace ();} shO
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catch(Exception e){e.printStackTrace ();} 7p(^I*|  
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Utility.log(nFileLength); #$QC2;/)F  
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return nFileLength; hGx)X64Mw  
} A7|!&fi  
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 pojQ/  
//保存下载信息（文件指针位置） W|oLS  
private void write_nPos() C{<qc,!4  
{ @54D<Lj  
try{
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output = new DataOutputStream(new FileOutputStream(tmpFile)); & Me%ZM0  
output.writeInt(nStartPos.length); y-gSal  
for(int i=0;i<nStartPos.length;i++) E-_FxBw  
{ s88lN=;  
// output.writeLong(nPos); E=.4(J7K  
output.writeLong(fileSplitterFetch.nStartPos);  g-MaP  
output.writeLong(fileSplitterFetch.nEndPos); y|1,h}H^n  
} q[#2`  
output.close(); <GI{`@5C  
} =#||&1U$  
catch(IOException e){e.printStackTrace ();} JJ5s |&}  
catch(Exception e){e.printStackTrace ();} x,a(O@  
} c8I : jDk:  
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//读取保存的下载信息（文件指针位置） ?r"'JO.w  
private void read_nPos() 7{ zkq
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{ a,3} o:f  
try{ mrR~[533j  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \*Roa&<!  
int nCount = input.readInt(); y#Je%tAe 2  
nStartPos = new long[nCount]; fX=o,=-f  
nEndPos = new long[nCount]; m0+X 109  
for(int i=0;i<nStartPos.length;i++) z;GR(;w/  
{ kYBy\  
nStartPos = input.readLong(); ,C%fA>?UF8  
nEndPos = input.readLong(); i#o:V/Z.  
} 3[plwe  
input.close(); 4viP lO  
} aV?dy4o$  
catch(IOException e){e.printStackTrace ();} j3`#v3  
catch(Exception e){e.printStackTrace ();} !e?g"5r{Bv  
} bM[!E8dF  
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private void processErrorCode(int nErrorCode) B -XM(Cj  
{ f>\guuG  
System.err.println("Error Code : " + nErrorCode); Gzxq] Mg  
} gPs%v`y)*D  
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//停止文件下载 ag Za+a  
public void siteStop() 0F
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{ EHk(\1!V  
bStop = true; 0'T*l2Z`2  
for(int i=0;i<nStartPos.length;i++) GRV#f06  
fileSplitterFetch.splitterStop(); VhdMKq~`  

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} 4 [2^#t[  
} 8YNii-pl  
//负责部分文件的抓取 HPT{83  
**FileSplitterFetch.java ts BPQ 8Ne  
*/ ^fVLM>p<;  
package NetFox; l AF/O5b  
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import java.io.*; g wM~W  
import java.net.*; _jkH}o '  
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public class FileSplitterFetch extends Thread { '\yp}r'u  
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String sURL; //File URL pAwmQ
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long nStartPos; //File Snippet Start Position x!$Dje}  
long nEndPos; //File Snippet End Position ZZ1s}TG  
int nThreadID; //Thread's ID 2p3ep,  
boolean bDownOver = false; //Downing is over xi5/Wc6  
boolean bStop = false; //Stop identical {4u8~whLp  
FileAccessI fileAccessI = null; //File Access interface pyPS5vWG  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4 I}xygV  
{ E8]PV,#xY  
this.sURL = sURL; `? ayc/TK  
this.nStartPos = nStart; u@!iByVAg  
this.nEndPos = nEnd; q7id?F}3&  
nThreadID = id; q3.L6M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 b}P5*}$:9"  
} d~[^D<5,D  
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public void run() gemjLuf  
{ .\*3t/R=X  
while(nStartPos < nEndPos && !bStop) }@Mx@ S  
{ k:(i sKIA  
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try{ C9oF*{  
URL url = new URL(sURL); !A>VzW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *|c*/7]<  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5u ED  
String sProperty = "bytes="+nStartPos+"-"; ag6hhkjA  
httpConnection.setRequestProperty("RANGE",sProperty); ,}&E=5MF\  
Utility.log(sProperty); QiU!;!s  
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InputStream input = httpConnection.getInputStream(); h-VpX6  
//logResponseHead(httpConnection);
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byte[] b = new byte[1024]; U:]b
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int nRead; 1\d$2N"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b@J&jE~d  
{ g%w@v$  
nStartPos += fileAccessI.write(b,0,nRead); )=\W sQ  
//if(nThreadID == 1) CL(,Q8yG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C~M~2@Iori  
} Vy = fm  
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Utility.log("Thread " + nThreadID + " is over!"); kmM4KP#&|  
bDownOver = true; sV7dgvVd  
//nPos = fileAccessI.write (b,0,nRead); ;K?fAspSH  
} Y^gK^?K  
catch(Exception e){e.printStackTrace ();} 2tvMa%1^  
} 6l#1E#]|  
} lv}U-vK  
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//打印回应的头信息 Y_`D5c:  
public void logResponseHead(HttpURLConnection con) 5Ah-aDBj  
{ 3OHP-oa.  
for(int i=1;;i++) uPe4Rr  
{ -"5x? \.{m  
String header=con.getHeaderFieldKey(i); O?@1</r^  
if(header!=null) 8xmw-s)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); R~b9)  
Utility.log(header+" : "+con.getHeaderField(header)); !)tXN=(1a  
else
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break; Kq`Luf  
} *Kt7"J  
} ~nb%w?vv  
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public void splitterStop() vnz.81OR  
{  49 3ik  
bStop = true; e%G-+6  
} HH6b{f@^  
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} 5S7`gN.  
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/* uYL6g:]+ZC  
**FileAccess.java !5`}s9hsF_  
*//文件访问(定位，写) #`GW7(M  
package NetFox; z/fRd6|[  
import java.io.*; Kggf!\MR8  
qx{.`AaZW  
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public class FileAccessI implements Serializable{ =&"Vf!7YR7  
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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 kRiWNEw  
RandomAccessFile oSavedFile; B<1*p,z  
long nPos; 5F2+o#*h  
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public FileAccessI() throws IOException ?xQlX%&`6  
{ *BXtE8 BU  
this("",0); @hzQk~Gdi  
} T|.Q81.NE  
? |8&!F  

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public FileAccessI(String sName,long nPos) throws IOException JF{,;&sj  
{ 3jS=  
oSavedFile = new RandomAccessFile(sName,"rw"); |B`-chK  
this.nPos = nPos; sxThz7#i)  
oSavedFile.seek(nPos); Y ga}8DU  
} LOnh
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*|t]6!aVLS  
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public synchronized int write(byte[] b,int nStart,int nLen) =AD/5E,3  
{ TdKl`"Iy  
int n = -1; (la<X<w  
try{ $#RD3#=?u  
oSavedFile.write(b,nStart,nLen); {6%uNT>|  
n = nLen; CzvlZDo  
} &]LwK5SR  
catch(IOException e) ~5!ukGK_  
{ ?>%u[g   
e.printStackTrace (); 7Ck;LF}>0  
} #Ejly2C,  
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return n; Q|ik\  
} Y43#];  
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} e< CPaun  
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/* .\d0lJSr  
**SiteInfoBean.java Q5<vK{  
*/ .R gfP'M  
package NetFox; rmabm\QY  

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#>- rKv.A  
public class SiteInfoBean { D{
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private String sSiteURL; //Site's URL .|aSGvE  
private String sFilePath; //Saved File's Path L3GJq{t  
private String sFileName; //Saved File's Name OeAPBhTmFj  
private int nSplitter; //Count of Splited Downloading File bv+e'$U3  
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public SiteInfoBean() OK)0no=OAK  
{//nSplitter的缺省值为5 8 6+>|  
//default value of nSplitter is 5 0sUc6_>e  
this("","","",5); &.z/dFmG  
} u]2k%TUY  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) GawO>7w8  
{ rx;U/)~#<  
sSiteURL= sURL; r{TNPa6!  
sFilePath = sPath; 8;'n.SC{  
sFileName = sName; eLTNnz  
this.nSplitter = nSpiltter; #NE^f2  
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} O.E0LCABC  
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public String getSSiteURL() yTn@p(J  
{ 2)A D'  
return sSiteURL; U .Od  
} ]03ZrZ! PM  
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public void setSSiteURL(String value)  %aKkk)s  
{ q"Md)?5N  
sSiteURL = value; 9y4rw]4zI  
} z3C^L  
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public String getSFilePath() XZInu5(  
{ )1vojp 4Za  
return sFilePath; PWMaB  
} 9CNHjs+-}s  
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public void setSFilePath(String value) r$F]e]Ic\  
{ zK 2wLX  
sFilePath = value; 4BT`|(7  
} h9I)<_}R  
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nnG2z@$-  
public String getSFileName() //Gvk|O1  
{ p*0Ve21i,  
return sFileName; [hL1PWKs  
} vb- 
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public void setSFileName(String value) Q:gn>/  
{ B`scuLl3  
sFileName = value; #Qr4Ke$g[l  
} skz]@{38  
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public int getNSplitter() L"iyjL<M  
{ -
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return nSplitter; ;g:bn5G  
} 4Aew )   
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public void setNSplitter(int nCount) Pp_3 nyQ  
{ r^t{Ii~  
nSplitter = nCount; b0b9#9x  
} ;q; C^l  
} .4<U*Xkt  
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g/,Bx!'8p  
/* mRH]'dlD7  
**Utility.java y8vH?^:%<  
*/ Kk>qgi$  
package NetFox; h.$__Gs  
`b")Bx|  
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public class Utility { \TB%N1^  
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public Utility() G'2=jHzMF  
{ C9U{^  
n&m?Bu
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} "qTC(F9N$.  
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//线程睡眠 @zynqh  
public static void sleep(int nSecond) )L<?g!j~  
{ @B'8SLoP  
try{ :aq>  
Thread.sleep(nSecond); Ui|a}`c  
} ?4>y2!OC9  
catch(Exception e) ^T&u!{82j  
{ ^q&wITGI  
e.printStackTrace (); X;6r$   
} `Kc %S^C'  
} W B*`zCM  
2Z`$  
//日志 \+Rwm:lI  
public static void log(String sMsg) ]X: rby$  
{ ZC5Yve8  
System.err.println(sMsg); |/\U^AHm"h  
} mrhp)yF  
380->  
6Sb'Otw.  
public static void log(int sMsg) C*s0r;  
{ H@2v<e@  
System.err.println(sMsg); ]PzTl {]  
} I4<{
R  
} 8q~FUJhU  
kh?#={]Z  
2rj/wakd  
/* Wl !!5\  
**TestMethod.java f1Yv hvWL  
*/ {rb-DB-/5M  
package NetFox; zK>'tFU  

w{r(F`  
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public class TestMethod { urrO1  
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public TestMethod() uq|vNLW26  
{ ///xx/weblogic60b2_win.exe  ?+ -/';  
try{ {V%%^Zhwy  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8tV=fSHd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TRk ?8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); npO@Haw  
fileFetch.start(); 1=/doo{^  
} hB P$9GR  
catch(Exception e){e.printStackTrace ();} E?Qz/*'zv  
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k+WO &g*|  
} uG=t?C6  
s<Ex"+  

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public static void main(String[] args) 0NCOz(L/  
{ T.Pklty  
new TestMethod(); 3R<ME c  
} nc3ltT,R  
} tDC0-N&6S~  
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