http断点续传简单实现（java)

/* W3\E;C-g0  
**SiteFileFetch.java y;<suGl
 
*/ #<Xq\yC51  
package NetFox; [
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import java.io.*; fqq4Qc)#U&  
import java.net.*; hiA\~}sl n  
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public class SiteFileFetch extends Thread { ED" fi$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean v-q-CI?B#  
long[] nStartPos; //开始位置 6akI5\b  
long[] nEndPos; //结束位置 $?]`2*i  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *FZav2]-  
long nFileLength; //文件长度 4#]g852  
boolean bFirst = true; //是否第一次取文件 8~s0%%{,M  
boolean bStop = false; //停止标志 d,Oagx  
File tmpFile; //文件下载的临时信息 WVOj;c  
DataOutputStream output; //输出到文件的输出流 %iEdUV\$  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3(,m(+J[S  
public SiteFileFetch(SiteInfoBean bean) throws IOException y,ub*-:  
{ udBIEW,`  
siteInfoBean = bean; N}ND()bf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); S4{vS?>j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .s!0S-RkC  
if(tmpFile.exists ()) '-[hy>t  
{ gTOx|bx  
bFirst = false; m6$&yKQ-=h  
read_nPos(); "e8EA!Ipte  
} :
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else oSkQ/5hg.  
{ bR~(Ry`  
nStartPos = new long[bean.getNSplitter()]; _;Xlw{FN^  
nEndPos = new long[bean.getNSplitter()]; Nq8 3 6HL  
} u~Po5W/i  
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} H.'9]*  
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public void run() _5~|z$GW  
{ _X;,,VEV!  
//获得文件长度 ZeU){CB  
//分割文件 wCR! bZ w  
//实例FileSplitterFetch ecoI-@CAI  
//启动FileSplitterFetch线程 T#E$sZ  
//等待子线程返回 YGLq
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try{ v~T)g"_|  
if(bFirst) i$@xb_  
{ D6&P9e_5  
nFileLength = getFileSize(); jl(D;JnF  
if(nFileLength == -1) E QU@';~8  
{ UXdc'i g  
System.err.println("File Length is not known!"); Qj_)^3`e  
} zuW4gJ  
else if(nFileLength == -2) HR8YPU5  
{ X';qcn_^
 
System.err.println("File is not access!"); V6HZvuXV!  
} jQ%1lQ#R)  
else "5 ~{  
{ C,W_0=!e  
for(int i=0;i<nStartPos.length;i++) A:GqR;;"x>  
{ .PVYYhrt
 
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y9<[n)>+  
} +ZW>JjP*  
for(int i=0;i<nEndPos.length-1;i++) rg k1.0U0  
{ d v[.u{#tP  
nEndPos = nStartPos[i+1]; Y$n+\K  
} r,0D I  
nEndPos[nEndPos.length-1] = nFileLength; L/-SWid)  
} ol/@)k^s>  
} 7z1@XO<D  
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//启动子线程 Tgtym"=xd  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~K3Lbd| r  
for(int i=0;i<nStartPos.length;i++) /}>8|#U3y  
{ jy5[K.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %H"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5CN=a2&  
nStartPos,nEndPos,i); JmK )Y# A  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h'=)dFw7  
fileSplitterFetch.start(); { >izfG,\  
} \i//Aq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y'odn;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); mhhc}dS(H  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8~-TN1H  
nEndPos = " + nFileLength); |^UQVNJ  
// fileSplitterFetch[nPos.length-1].start(); )^s>21  
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//等待子线程结束 z[
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//int count = 0; , otXjz  
//是否结束while循环 Ji9o0YR  
boolean breakWhile = false; :'C?uk ?  
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while(!bStop) OF']-  
{ "i/GzD7`n  
write_nPos(); hDW_a y4  
Utility.sleep(500); wdBBx\FP  
breakWhile = true; 2ns,q0I A  
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for(int i=0;i<nStartPos.length;i++) ~zac.:a8  
{ k# Ho7rS&  
if(!fileSplitterFetch.bDownOver) kJf0..J[#<  
{ 6c-'CW  
breakWhile = false; =lk'[P/p`  
break; Bl6I@w  
} s-Yu(X2  
} <|Lz#iV37  
if(breakWhile) T3 ie-G@<  
break; ,"#nJC  
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//count++; 6IT6EkiT  
//if(count>4)
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// siteStop(); XBCHJj]k  
} T$2A2gb`  
y< dBF[  
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System.err.println("文件下载结束！"); tg#jjXV\0p  
} 1z&"V}y  
catch(Exception e){e.printStackTrace ();} 6*S/frE  
} *#}=>, v  
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//获得文件长度 E`^D9:3:)  
public long getFileSize() |&MoQxw@  
{ TK' 5NM+4  
int nFileLength = -1; ll$mRC  
try{ uuFQTx))  
URL url = new URL(siteInfoBean.getSSiteURL()); &ot^+uVH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <>n|_6'$90  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7ixG{yu  
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int responseCode=httpConnection.getResponseCode(); R-Lpgi<a"  
if(responseCode>=400) F3!@|/<w  
{ #BBDI  
processErrorCode(responseCode); &0Y |pY  
return -2; //-2 represent access is error a-,*iK{_u  
} @"fv[=Xb  
!=.y[Db=  
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String sHeader; !]uB
4  
_^b\#Jz4U3  
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for(int i=1;;i++) t-C|x)J+  
{ ]Bf1p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r-EIoZ"P  
//Utility.log(in.readLine()); Y)]VlV!`  
sHeader=httpConnection.getHeaderFieldKey(i); L9Zz-Dr s  
if(sHeader!=null) =GP L>a&  
{ k CGb~+  
if(sHeader.equals("Content-Length")) m ne)c[Qn  
{ ivl %%nY'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $04lL/;  
break; {4vWSb  
} [ol
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} CXoiA"P  
else R#~l
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break; *.wj3'wV  
} cyWb*Wv  
} ~x'8T!M{  
catch(IOException e){e.printStackTrace ();} Hc\@{17  
catch(Exception e){e.printStackTrace ();} =2GKv7q$x,  
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Utility.log(nFileLength); xu-bn  
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return nFileLength; m2(}$z3e  
} wY\,b*x  
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ke W7pN?  
//保存下载信息（文件指针位置） r>bgCQ#-n  
private void write_nPos() pd:YR;  
{ lj&\F|-i  
try{ R
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output = new DataOutputStream(new FileOutputStream(tmpFile)); s1Wn.OGR4  
output.writeInt(nStartPos.length); 6 A]a@,PC  
for(int i=0;i<nStartPos.length;i++) mpwh=  
{ {_\dwe9  
// output.writeLong(nPos); z@19gD#8  
output.writeLong(fileSplitterFetch.nStartPos); 4|\M`T  
output.writeLong(fileSplitterFetch.nEndPos); u|$HA>F[  
} ShV_8F z  
output.close(); Lhg  
} CfrO1iF  
catch(IOException e){e.printStackTrace ();} & }j;SK5  
catch(Exception e){e.printStackTrace ();} *< fJgc"3  
} 5WfZd  
CL5^>.}  
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//读取保存的下载信息（文件指针位置） p</t##]3ks  
private void read_nPos() 8kU(>' ^_:  
{ q*4@d)_&  
try{ 'Tqusr>lPY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p
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int nCount = input.readInt(); `]GL3cIh:  
nStartPos = new long[nCount]; ti1R6oSn  
nEndPos = new long[nCount]; V:5aq.o!  
for(int i=0;i<nStartPos.length;i++) };9/J3]m  
{ k??CXW  
nStartPos = input.readLong(); A9ld9R  
nEndPos = input.readLong(); Txe*$T,(  
} c1_Z
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input.close(); @zw&-b:qI  
} SufM~9Ll  
catch(IOException e){e.printStackTrace ();} _[&.`jTF
n  
catch(Exception e){e.printStackTrace ();} jb/C\2U4)  
} /\Xe'&  
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private void processErrorCode(int nErrorCode) .sj/Lw}  
{ ]QHZ[C  
System.err.println("Error Code : " + nErrorCode); CcV@YST?  
} @m`H~]AU  
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MoiRAO  
//停止文件下载 +Gy9K  
public void siteStop() &y73^"%  
{ ia /#`#.  
bStop = true; X[w]aJnAr  
for(int i=0;i<nStartPos.length;i++) _RzoXn{1e  
fileSplitterFetch.splitterStop();
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} nHXPEbq-g  
} /:\27n  
//负责部分文件的抓取 4UW)XLu6T7  
**FileSplitterFetch.java 
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*/ Ax@
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package NetFox; Q9p2.!/C1  
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import java.io.*; N@'l:N'f4  
import java.net.*; 'MyJw*%b]  
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public class FileSplitterFetch extends Thread { X>yE<ni  
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String sURL; //File URL K!>3`[:I"  
long nStartPos; //File Snippet Start Position }7fzEo`g  
long nEndPos; //File Snippet End Position b/#<::D `  
int nThreadID; //Thread's ID l_2l/ff9  
boolean bDownOver = false; //Downing is over L4u.cHJ}0  
boolean bStop = false; //Stop identical -s0J8b  
FileAccessI fileAccessI = null; //File Access interface / )[\+Nc  
@LU[po1I  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e+2lus,u6t  
{ ~<Wa$~oY  
this.sURL = sURL; +Ezl.
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this.nStartPos = nStart; I(j{D>v  
this.nEndPos = nEnd; l.}gWN9-  
nThreadID = id; Bz:Hp{7&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d|UH AX  
} b-c6.aKf|  
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public void run() \ sz
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{ j~;y~Cx?  
while(nStartPos < nEndPos && !bStop) l<"B[  
{ G[zysxd  
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try{ C<^S$  
URL url = new URL(sURL); _\,4h2(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6is+\  
httpConnection.setRequestProperty("User-Agent","NetFox"); rg%m
 
String sProperty = "bytes="+nStartPos+"-"; 3],(oQq^  
httpConnection.setRequestProperty("RANGE",sProperty); F
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Utility.log(sProperty); ^:O*Sx.CA  
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InputStream input = httpConnection.getInputStream(); X0$?$ta  
//logResponseHead(httpConnection); @ <'a0)n>  
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byte[] b = new byte[1024]; h{)`W ]~  
int nRead; 1o   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) AMK3I`=8WO  
{ N=8CVI  
nStartPos += fileAccessI.write(b,0,nRead); to\$'2F"q  
//if(nThreadID == 1) QX(t@VP  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EScy!p\*  
} f
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Utility.log("Thread " + nThreadID + " is over!"); 4tapQgj24  
bDownOver = true; G6"4JTWO  
//nPos = fileAccessI.write (b,0,nRead); ]zvOM^l~  
} T?-K}PUcQ  
catch(Exception e){e.printStackTrace ();} 7tY~8gQel  
} itO1ROmu  
} sQT,@+JEr  
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7 :u+-U  
//打印回应的头信息 yN}<l%  
public void logResponseHead(HttpURLConnection con) Z>'hNj)ju  
{ I=K<%.  
for(int i=1;;i++) MY&?*pV)  
{ V5I xZn%  
String header=con.getHeaderFieldKey(i); iW?NxP  
if(header!=null) ,#.^2O9-^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3ZYrNul"  
Utility.log(header+" : "+con.getHeaderField(header)); rV I-Yb  
else `zcpaE.@  
break; :\1vy5 _  
} W5RZsS]  
} -dUXd<=ue  
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public void splitterStop() _x7>d:C  
{ _1\H{x  
bStop = true;  qJj5_  
} LkX
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} %vrUk;<35  
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/* .
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**FileAccess.java !AL?bW  
*//文件访问(定位，写) _3_o/I  
package NetFox; (Z>vbi%  
import java.io.*; sJLJVSv8c  
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public class FileAccessI implements Serializable{ bEzy KrN\  
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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 lN::veD  
RandomAccessFile oSavedFile; ?~~,?Uxw!  
long nPos; NVo=5  
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public FileAccessI() throws IOException 7(5 wP(  
{ }9&~+Q2  
this("",0); 9t0NO-a  
}  Ml,87fo  
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public FileAccessI(String sName,long nPos) throws IOException _&F*4t!n_  
{
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oSavedFile = new RandomAccessFile(sName,"rw"); *U4eL-  
this.nPos = nPos; ljj}XJQ  
oSavedFile.seek(nPos); 32):&X"AIh  
} &#[6a&9#[A  
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public synchronized int write(byte[] b,int nStart,int nLen) V8J!8=2  
{ XiUae{j`  
int n = -1; >c8EgSZJ  
try{ >1d`G%KfG  
oSavedFile.write(b,nStart,nLen); ,7|2K&C5  
n = nLen; }o#6g|"\sY  
} / CVhvK  
catch(IOException e) (K->5rSU  
{ ^<'=]?xr  
e.printStackTrace (); C&KH.h/N  
} HA(
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return n; 1'[_J  
} td
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} n8>(m,  
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/* th(<S  
**SiteInfoBean.java WMd5Y`
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*/ >`c-Fqk  
package NetFox; YXhxzH hPd  
keWqL]  
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public class SiteInfoBean { L+y90 T6?  
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private String sSiteURL; //Site's URL =;^#5dpt$  
private String sFilePath; //Saved File's Path seEG~/U<  
private String sFileName; //Saved File's Name 3]}wZY0  
private int nSplitter; //Count of Splited Downloading File } ^67HtNQ  
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public SiteInfoBean() .#y.:Pb|e  
{//nSplitter的缺省值为5 E%6}p++  
//default value of nSplitter is 5 7nAB^~)6l  
this("","","",5); Z-,'M tD  
} k~ZE4^dM  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xA>O4SD  
{ h*9s^`9)  
sSiteURL= sURL; H"A|Z6y$^  
sFilePath = sPath; ?4,e?S6,[  
sFileName = sName; ZkZTCb`/l  
this.nSplitter = nSpiltter; 48 `k"Uy  
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} m#a0HH  
z tLP {q#  
4=E9$.3a  
public String getSSiteURL() |+Fko8-  
{ w8df-]r  
return sSiteURL; L^zF@n^5A  
} w(KB=lA2  
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public void setSSiteURL(String value) MxO0#  
{ yBwgLn  
sSiteURL = value; Td !7Rx _  
} VMZ"i1rP  

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public String getSFilePath() 5g3D}F>OJ  
{ DPE]<oM  
return sFilePath; pO.+hy  
} s*k[Fbi  
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HTz&h#)JQ  
public void setSFilePath(String value) 5[_|+  
{ '%$)"g]/#  
sFilePath = value; CG(G){u&  
} bZ.q?Hlfk  
P
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public String getSFileName() O%.c%)4Xo  
{ "[ 091<  
return sFileName; CfoT$g  
} ? LA>5  
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public void setSFileName(String value) Bu\:+3)  
{ +&7D ;wj=  
sFileName = value; "r Bb2.  
} XUrxnJ4  
qMrBTq[  
'7UW\KEB[}  
public int getNSplitter() yrnIQu*Uu  
{ 4ACL|RF)A  
return nSplitter; mgk<PY  
} 1I*b7t  
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public void setNSplitter(int nCount) H +O7+=&  
{ DRC2U%[  
nSplitter = nCount; jW^@lH EU  
} ]\y:AkxhJ  
} b'Scoa7@'  
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~9Nn8g6  
/* gi|j! m  
**Utility.java 06FBI?;|=  
*/ aB6F<"L,  
package NetFox; l0^~0xlED  
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public class Utility { '$@bTW  
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bnb:4?d]  
public Utility() Cx.GEY|0  
{ A.@
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}
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//线程睡眠 LZirw'  
public static void sleep(int nSecond) YY\$lM  
{ [ &cCE   
try{ WJp9io[GM  
Thread.sleep(nSecond); 2m]CmdV^  
} afVl)2h  
catch(Exception e) n2NxO0  
{ K'6dlwn).  
e.printStackTrace (); "enGWIH  
} KiXRBFo  
}  F'!pM(+  
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//日志 ,P&.qg i=(  
public static void log(String sMsg) vhA4ol  
{ hmfO\gc}y  
System.err.println(sMsg); 5C}1iZEJ  
} 8U98`# i  
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s<f<:BC  
public static void log(int sMsg) ;<j[0~qp:  
{ ?Vy%<f$  
System.err.println(sMsg); lV4|(NQ9  
} vkFq/+'U  
} eI%{/>  
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sp=;i8Y 3  
/* 8.9Z0  
**TestMethod.java tVB9kxtE  
*/ f-lM[\ma_  
package NetFox; IYIlab\TZ  
1{TmK9U  
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public class TestMethod { fwe4f  
>l<`)4*H  
8zDLX,M-  
public TestMethod() 3#O Rfr(  
{ ///xx/weblogic60b2_win.exe ID/=YG@  
try{ {yo<19kV@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); I ,j,Hz0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6:Fb>|]*PY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); L_TM]0D>7  
fileFetch.start(); |@6t"P]@  
} :gD=F&V  
catch(Exception e){e.printStackTrace ();} U3R;'80 f  
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it Byw1/  
} us/}_r74N*  
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public static void main(String[] args) %25GplMT  
{ d) i:-#Q  
new TestMethod(); >bwB+-lyL  
} FTVV+9.
l:  
} 7gX#^YkE+k  
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