http断点续传简单实现（java)

/* mBgx17K/-_  
**SiteFileFetch.java A
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*/ KZ >"L  
package NetFox; 2'^OtM,  
import java.io.*; u(G;57ms  
import java.net.*; ORPl^n-  
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public class SiteFileFetch extends Thread { m=l3O:~J  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^d$e^cU  
long[] nStartPos; //开始位置 T^H) lC#R  
long[] nEndPos; //结束位置 GDQg:MgX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^EBM;&;7  
long nFileLength; //文件长度 AA%g^PWpR  
boolean bFirst = true; //是否第一次取文件 Ecl7=-y  
boolean bStop = false; //停止标志 ~S{\wL53  
File tmpFile; //文件下载的临时信息 9oN'.H^  
DataOutputStream output; //输出到文件的输出流 A(sx5Ynp  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @:&dOqQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException YZtA:>;p  
{ [&kk  
siteInfoBean = bean; f2e$BA  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]T$w7puaJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); K>JU/(  
if(tmpFile.exists ()) \yizIo.Y`  
{ f!Nc+  
bFirst = false; 1`JN  
read_nPos(); WjxB
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} =y/Lbe}:  
else 5{f/H] P  
{ X?xm1|\  
nStartPos = new long[bean.getNSplitter()]; a9JJuSRC  
nEndPos = new long[bean.getNSplitter()]; Vx8.FNJh  
} " yl"A4p S  
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} (:k`wh
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public void run() ?bi^h/f  
{ -+Ji~;b  
//获得文件长度 Z+Zh;Ms  
//分割文件 R.$Y1=U6  
//实例FileSplitterFetch 4nXS9RiF2  
//启动FileSplitterFetch线程 .y/?~+N^  
//等待子线程返回 2;7GgO~  
try{ Q*o4zW  
if(bFirst) 2Ps`!Y5  
{ E1[%~Cpw*  
nFileLength = getFileSize(); [NDYJ'VGe  
if(nFileLength == -1) u3!!_~6,z  
{ \zDV|n~{w  
System.err.println("File Length is not known!"); @TG~fJSA12  
} 4tKf  
else if(nFileLength == -2) Y0'^S<ox  
{ LM`#S/h  
System.err.println("File is not access!"); #>NZN1  
} RtEkd_2  
else zOp"n\  
{ v65r@)\`  
for(int i=0;i<nStartPos.length;i++) f 8U;T$)  
{ Kwau:_B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *xKR;?.  
} M" \y2   
for(int i=0;i<nEndPos.length-1;i++) m>:ig\  
{ %uMsXa  
nEndPos = nStartPos[i+1];  .l'QCW9  
} 0nn#U  
nEndPos[nEndPos.length-1] = nFileLength;
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} ,PAKPX9v_F  
} |
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//启动子线程 XRin~wz|S  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5Ep  
for(int i=0;i<nStartPos.length;i++) 3g?T,|2K  
{ ?+
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W5 }zJ)x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), '?4[w]0J<  
nStartPos,nEndPos,i); N/p_6GYMa  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nV1
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fileSplitterFetch.start(); ]e9kf$'  
} **[p{R]8o  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jws(`mIf\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~A( Pa-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U)6
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nEndPos = " + nFileLength); W3kilhZ  
// fileSplitterFetch[nPos.length-1].start(); H2p;J#cv@  
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//等待子线程结束 XO>Y*7rO  
//int count = 0; %0'f`P6  
//是否结束while循环 v4Gk
f  
boolean breakWhile = false; e V#H"fM  
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while(!bStop) yDrJn* r^  
{ _L ].n)b  
write_nPos(); [;bLlS,  
Utility.sleep(500); ah.Kb(d:  
breakWhile = true; nNr3'6lz  
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for(int i=0;i<nStartPos.length;i++) Q*5d~Yr]R  
{ :A[/;|&  
if(!fileSplitterFetch.bDownOver) Gy5W;,$q  
{ :1I,:L  
breakWhile = false; c4|.!AQ>  
break; }HzZj;O^2>  
} \v<}{\.|$  
} ~kga+H  
if(breakWhile) {u5@Yp  
break; WF]:?WE%
 
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//count++; _<8y^y
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//if(count>4) !WmpnPr1  
// siteStop(); POf \l  
} "#()4.9  
4#T'Fy].  
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System.err.println("文件下载结束！"); ,DjZDw  
} K:0RP?L  
catch(Exception e){e.printStackTrace ();} DRnXo-Aaj  
} ;%)i/MGEB  
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//获得文件长度 5D#*lMSP"'  
public long getFileSize() &xVWN>bd^  
{ p
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int nFileLength = -1; 6\`,blkX  
try{ X*sF-T$.  
URL url = new URL(siteInfoBean.getSSiteURL()); AxeWj%w@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]3v  
httpConnection.setRequestProperty("User-Agent","NetFox"); W^x[maz  
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int responseCode=httpConnection.getResponseCode(); 4-\a]"c  
if(responseCode>=400) 3+Q6<MS q  
{ {|fA{ Q_R  
processErrorCode(responseCode); 5H79) n>  
return -2; //-2 represent access is error *?uF&( 0  
} myYe~f4=HQ  
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String sHeader; 3|A"CU/z@  
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for(int i=1;;i++) rScmUt  
{ 0-5:"SN'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r"n)I$  
//Utility.log(in.readLine()); H=dj\Br`  
sHeader=httpConnection.getHeaderFieldKey(i); BKIt,7j  
if(sHeader!=null) 6V8"[0U  
{ rnW i<Se  
if(sHeader.equals("Content-Length")) 0ul2rZc  
{ x&;SLEM   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); a+X X?uN{  
break; 0I.7I#'3O  
} 2
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} Jlzhn#5c-  
else F8
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break; q3;HfZ  
} "];19]x6q  
} u^`B#b'  
catch(IOException e){e.printStackTrace ();} /g_}5s-Z  
catch(Exception e){e.printStackTrace ();} ak'RV*>mT  
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Utility.log(nFileLength); 8\[6z0+;  
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return nFileLength; 6l50IWj,T  
} .rS0zU  
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//保存下载信息（文件指针位置） k:c)|2  
private void write_nPos() _/K
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{ l9-(ofY*J  
try{ gn'. 9";j  
output = new DataOutputStream(new FileOutputStream(tmpFile)); zW\&q!`IRP  
output.writeInt(nStartPos.length); ~*H!zKIx  
for(int i=0;i<nStartPos.length;i++) WT1ch0~2  
{ GU_R6Wt+  
// output.writeLong(nPos); vmL0H)q  
output.writeLong(fileSplitterFetch.nStartPos); t,&1~_9  
output.writeLong(fileSplitterFetch.nEndPos); w,^!kO0)~8  
} { c]y<q  
output.close(); %rYd=Ri  
} >R :Bkf-  
catch(IOException e){e.printStackTrace ();} p0[ %+n%  
catch(Exception e){e.printStackTrace ();} (A?/D!y  
} ~ZT(@w  
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//读取保存的下载信息（文件指针位置） F(mm0:lT  
private void read_nPos() /-1[}h%U'  
{ ,
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try{ 8nNRn[oS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  z7>  
int nCount = input.readInt(); D/{hLp{  
nStartPos = new long[nCount]; %I?uO( @  
nEndPos = new long[nCount]; .I<#i9Le  
for(int i=0;i<nStartPos.length;i++) Ub0g{   
{ '9*(4/,UJJ  
nStartPos = input.readLong(); %i$]S`A}  
nEndPos = input.readLong(); r65/O5F  
} O\8_;Gc;  
input.close(); >}Fe9Y.o  
} Qn6'E  
catch(IOException e){e.printStackTrace ();} 6o!+E@V b  
catch(Exception e){e.printStackTrace ();} |cUTP!iy  
} Y2HF  
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private void processErrorCode(int nErrorCode) UTC|8  
{ ]gx]7  
System.err.println("Error Code : " + nErrorCode); Z2!O)
8  
} ,p {|f}0  
5Ay\s:hb[u  
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//停止文件下载 #+
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public void siteStop() 1U^;fqvja  
{ s8Bbet  
bStop = true; Z]jm.'@z@  
for(int i=0;i<nStartPos.length;i++) krnxM7y  
fileSplitterFetch.splitterStop(); B}Qpqa=_c  
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} ~|QhWgq  
} {)=h  
//负责部分文件的抓取 +`'=K ;{U  
**FileSplitterFetch.java u?,M`w0'  
*/ qp;eBa  
package NetFox; 9=YX9nP  
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XA PqRJ*Z  
import java.io.*; HtFc+%=  
import java.net.*; @A?Ss8p'  
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public class FileSplitterFetch extends Thread { f2ea|l  
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String sURL; //File URL =cz^g^
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long nStartPos; //File Snippet Start Position Ww\M3Q`h  
long nEndPos; //File Snippet End Position g4z*6L,u  
int nThreadID; //Thread's ID 5\S s`#g  
boolean bDownOver = false; //Downing is over !79eF)  
boolean bStop = false; //Stop identical KUD&vqx3  
FileAccessI fileAccessI = null; //File Access interface cCa+UTxaJ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P]cC2L@Vbi  
{ ;[)O{%s  
this.sURL = sURL; d0U-:S-  
this.nStartPos = nStart; mQd L"caA  
this.nEndPos = nEnd; V)<Jj  
nThreadID = id; sQ"; t=yC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 UmEc")3  
} h[*:\P`  
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public void run() lf2Q  
{ W*.j=?)\[  
while(nStartPos < nEndPos && !bStop) X5_T?  
{  4>R)2g  
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try{ l~(A(1  
URL url = new URL(sURL); 0^('hS&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'Bx"i  
httpConnection.setRequestProperty("User-Agent","NetFox"); m:-=K
  
String sProperty = "bytes="+nStartPos+"-"; v{r,Wy3  
httpConnection.setRequestProperty("RANGE",sProperty); 5.M82rR;~  
Utility.log(sProperty); BWF>;*Xro  
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InputStream input = httpConnection.getInputStream(); eXA@J[-M:  
//logResponseHead(httpConnection); ,II-:&H  
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byte[] b = new byte[1024]; vX;~m7+  
int nRead; N!lQ;o'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ioT+,li  
{ T/$hN hQK  
nStartPos += fileAccessI.write(b,0,nRead); 1c4@qQyo  
//if(nThreadID == 1) b=PB"-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); It#T\fU  
} nnZM{<!hF  
4Ai#$SHLm  
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Utility.log("Thread " + nThreadID + " is over!"); bIy:~z5   
bDownOver = true; ;d<RPVE:  
//nPos = fileAccessI.write (b,0,nRead); \AY*x=PF  
} :{=2ih-}  
catch(Exception e){e.printStackTrace ();} Q@ghQGn#  
} vYNu=vnM  
} 7El:$H  
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//打印回应的头信息 (5h+b_eB  
public void logResponseHead(HttpURLConnection con) qr'P0+|~5  
{ |Ye%HpTTv  
for(int i=1;;i++) WUK{st.z  
{ krecUpo  
String header=con.getHeaderFieldKey(i); PzH#tG&.j  
if(header!=null) u.ub:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^GC 8^f  
Utility.log(header+" : "+con.getHeaderField(header)); tdi^e;:?  
else }%Vx2Q  
break; u(C?\HaH  
} wPQRm[O|  
} \(;X3h  
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public void splitterStop() :d}@Z}2sD  
{ Bs;.oK5!n@  
bStop = true; "zx4k8  
} vN$j@h .  
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} w;]~2$  
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/* xa?   
**FileAccess.java &k@r23V7r  
*//文件访问(定位，写) vI0::ah/  
package NetFox; 2`nOYK  
import java.io.*; *Ry{}|_8  
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public class FileAccessI implements Serializable{ ST25RJC  
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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 ]`u_d}`  
RandomAccessFile oSavedFile; rF)[ Sed:T  
long nPos; ]x^v;r~  
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public FileAccessI() throws IOException HN~  
{ 4t< mX  
this("",0); ~[3B<^e  
} ^gd[UC-"w  
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public FileAccessI(String sName,long nPos) throws IOException +9[s(E?SY  
{ Hribk[99  
oSavedFile = new RandomAccessFile(sName,"rw"); WJF#+)P:Y  
this.nPos = nPos; pqnZ:'V  
oSavedFile.seek(nPos); q}MPl2  
} mIm.+U`a2  
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public synchronized int write(byte[] b,int nStart,int nLen) }.74w0~0^  
{ TYN~c(  
int n = -1; mQqv{1  
try{ :Miri_l  
oSavedFile.write(b,nStart,nLen); C">w3#M%  
n = nLen; ,/6 aA7(  
} F2
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catch(IOException e) $pGdGV\H  
{ #0gwN2Nv"L  
e.printStackTrace (); GMJ</xG
  
} *9I/h~I  
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return n; `D9AtN] R  
} "*N=aHsj  
/ +9o?Kxya  
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} NB[(O#  
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/* WPu{ ]<pl  
**SiteInfoBean.java YH^h?s  
*/ 2c4x=%  
package NetFox; iw)^;8q  
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public class SiteInfoBean { \.,qAc\[  
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private String sSiteURL; //Site's URL OPP^n-iPr  
private String sFilePath; //Saved File's Path ]> 36{k]&  
private String sFileName; //Saved File's Name JLFZy\  
private int nSplitter; //Count of Splited Downloading File 1w/Ur'8we  
.,$<waGD  
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public SiteInfoBean() !Ey=  
{//nSplitter的缺省值为5 k;W`6:Kjp  
//default value of nSplitter is 5 y+g01z  
this("","","",5); SB#Y^!  
} Obb"#
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MrGq{,6C  
{ H$o=kQN  
sSiteURL= sURL; KqNbIw*sR  
sFilePath = sPath; 4Cn% h)w  
sFileName = sName; zIE{U  
this.nSplitter = nSpiltter; 7Fd`MTo  
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} ZgD%*bH*B  
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public String getSSiteURL() 5y`n8. (?  
{ AZgeu$:7p<  
return sSiteURL; {BS}9jZx  
} ! O~:  
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public void setSSiteURL(String value) |2t1m 6\j  
{ p
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sSiteURL = value; Uzzt+Iwm  
} &uMx*TTY  
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public String getSFilePath() lH#C:n  
{ 9>I&Z8J$M  
return sFilePath; CNkI9>L=W`  
} ,^K}_z\9f  
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^_rBEyz@  
public void setSFilePath(String value) pcrarj  
{ c`E0sgp  
sFilePath = value; bMp[:dw`y  
} wS"`~Ql_  
:H(wW   
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public String getSFileName() 9m+ejTK{U  
{ 4A{6)<e  
return sFileName; ^1mnw@04  
} LyuA("xB#  
b2 5.CGF  
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public void setSFileName(String value) E3"j7y[S  
{ >.o<}!FW  
sFileName = value; 2K VX  
} uy'qIq  
4Wk`P]?^  
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public int getNSplitter() IDK~ (t  
{ F(DM$5z[  
return nSplitter; 9~5LKg7Ac  
} o5;|14O  
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public void setNSplitter(int nCount) qF3s&WI  
{ l0K_29^  
nSplitter = nCount; Z/e^G f#i  
} lKBI3oYn  
} E@J}(76VS  
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/* @QfbIP9  
**Utility.java P/,ezVb=  
*/ qE*hUzA  
package NetFox; 7TB&Q*Zf  
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public class Utility { ^~kfo|  
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public Utility() TdL/tg!  
{ L~!Lq4]V\g  
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}
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//线程睡眠 xzb{g,c   
public static void sleep(int nSecond) Exz(t'  
{ ZK`x(h{p)  
try{ h3(B7n7  
Thread.sleep(nSecond); }_fVv{D   
} c|F26$rv  
catch(Exception e) I3AxKA  
{ 5|g#>sx>`q  
e.printStackTrace (); 0Ci:w|J  
} g+QNIM>  
} SD.c9  
v M $Tn  
//日志 "Xj>dB1~  
public static void log(String sMsg) Q5c13g2
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{ ^)1!TewCY  
System.err.println(sMsg); ,ik\MSS  
} F>ps&h  
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S~\u]j^%y  
public static void log(int sMsg) n:[LsbTk  
{ z<u@::  
System.err.println(sMsg); Dw&_6\F@  
} ]64?S0p1c!  
} kjRL|qx`a;  
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4p]hY!7  
/* }^ZPah  
**TestMethod.java Ombvp;  
*/ ol@LLT_m  
package NetFox; 'cf8VD  
fHacVjJ  
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public class TestMethod { PHqIfH[  
ZZU"Q7`^  
Am)XbN')1  
public TestMethod() *h2)$^P%  
{ ///xx/weblogic60b2_win.exe 8p.O rdp  
try{ 8EAkM*D w  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k1_3\JO"6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); wIK
&EGQ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ks.kn7<l  
fileFetch.start(); 
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} Z{ b($po  
catch(Exception e){e.printStackTrace ();} oWdvpvO  
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} 3&7$N#v  
 ^6Y:9+  
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public static void main(String[] args) Wj#Gm  
{ r$z0C&5  
new TestMethod(); s(M8 Y  
} /]"2;e-s+  
} ypsT:uLT  
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