http断点续传简单实现（java)

/* "i'bTVs  
**SiteFileFetch.java $]d*0^J 6  
*/ Uv?'m&_  
package NetFox; p|6v~  
import java.io.*; ~JZ3a0$^  
import java.net.*; l_FGZ!7  
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public class SiteFileFetch extends Thread { )&NAs  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #Olg(:\  
long[] nStartPos; //开始位置 e]W0xC-  
long[] nEndPos; //结束位置 ?z`MPdO  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2@@l{Y0f6  
long nFileLength; //文件长度 4yV].2#rl"  
boolean bFirst = true; //是否第一次取文件 \,W.0#D8v4  
boolean bStop = false; //停止标志 A-E+s~U8  
File tmpFile; //文件下载的临时信息 Q/_#k/R  
DataOutputStream output; //输出到文件的输出流 wuK=6RL  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ol!86rky  
public SiteFileFetch(SiteInfoBean bean) throws IOException yM$J52#d#  
{ <Q`&o@I  
siteInfoBean = bean; \4~AI=aw,T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); HR{s&ho  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6o}V@UzqV  
if(tmpFile.exists ()) B< ;==|  
{ &a~=
b,  
bFirst = false; 3_ 2hC!u!K  
read_nPos(); VAj<E0>  
} &/F_*=VE  
else 3l:QeZ  
{ B#N7qoi  
nStartPos = new long[bean.getNSplitter()]; 2Y
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nEndPos = new long[bean.getNSplitter()]; &{^eU5  
} XDmbm*~i  
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} _'iDF  
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public void run() 2ChWe}f  
{ (9.yOc4  
//获得文件长度 cK}Pf+r>  
//分割文件 ,7/ _T\d<  
//实例FileSplitterFetch hTS
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//启动FileSplitterFetch线程 xEoip?O?7F  
//等待子线程返回 r#h {$i
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try{ -ut=8(6&  
if(bFirst) =:K@zlO:  
{ ofCVbn  
nFileLength = getFileSize(); L
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if(nFileLength == -1) mZoD033H  
{ h)B!LAr  
System.err.println("File Length is not known!"); lSCY5[?  
} Z] {@H  
else if(nFileLength == -2) Kdt|i93  
{ o<\6Rm  
System.err.println("File is not access!"); LD.Ck
6@  
} Z;*`fd?8  
else /Dd\PjIH{  
{ pcpxe&S  
for(int i=0;i<nStartPos.length;i++) kyAs'R@z  
{ b.Su@ay@(^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oI$V|D3 9  
} 0/A-#'>  
for(int i=0;i<nEndPos.length-1;i++) 2ij/N%
l  
{ U>3 >Ex  
nEndPos = nStartPos[i+1]; wXCyj+XB*  
} {visv{R<  
nEndPos[nEndPos.length-1] = nFileLength; }u
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I  
} -N^=@Yx)  
} ' o=E!?  
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//启动子线程 Yk7"XP[Y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; twbcuaCTW  
for(int i=0;i<nStartPos.length;i++) 7+8bL{  
{ XARSGAuw  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a-Y6w5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kgc.8  
nStartPos,nEndPos,i); %F3}/2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  sL~,  
fileSplitterFetch.start(); Ar~{=X  
} 03
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \(9p&"Q-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3;D?|E]1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5`yPT>*#m>  
nEndPos = " + nFileLength); }9}w8R~E  
// fileSplitterFetch[nPos.length-1].start(); N[ Q#R~Hn<  
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sN@j5p^jc  
//等待子线程结束 MgP{W=h2  
//int count = 0; 0~i qG  
//是否结束while循环 e[p^p!a  
boolean breakWhile = false; W9jNUZVXE#  
ORtg>az\%  
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while(!bStop) R`3x=q  
{ JJNmpUJ  
write_nPos(); 5=.7\#D  
Utility.sleep(500); ahoh9iJ  
breakWhile = true; qa;EI ;8  
Xa*?<(^`  
'Aet{A=9  
for(int i=0;i<nStartPos.length;i++) A?sNXhh  
{ g\j>qUjs%Q  
if(!fileSplitterFetch.bDownOver) C&oxi$J:p+  
{ FLEg0/m0  
breakWhile = false; 6NSO>/E  
break; o@@_J@}#  
} r'PE5xqF  
} SNxz*`@4  
if(breakWhile) <tU :U<ea]  
break;
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ZU^Q1}</5  
]nHe$x!2]  
//count++; e mC\i  
//if(count>4) m^Rd Iy)  
// siteStop(); q4zSS #]A  
} nYgx9Q"<om  
q"l>`KCG`  
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System.err.println("文件下载结束！"); {'&8`d  
} (A|B@a!Y>  
catch(Exception e){e.printStackTrace ();} o:f|zf> i<  
} |y'b217t  
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//获得文件长度 l [x%I  
public long getFileSize() ;\q<zO@x  
{ ew/KZE  
int nFileLength = -1; L&rO6  
try{ - Ra\^uz  
URL url = new URL(siteInfoBean.getSSiteURL()); 'bG1U`v=3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WY3_7k8u  
httpConnection.setRequestProperty("User-Agent","NetFox"); U0zW9jB  
&F9OZMK=  
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int responseCode=httpConnection.getResponseCode(); V9gVn?O0  
if(responseCode>=400) @eA %(C  
{ ul}
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processErrorCode(responseCode); QM7[O]@  
return -2; //-2 represent access is error bQ i<0|S  
} $kM'  
s%hU*^ 8  
X #H:&*[!  
String sHeader; c-v*4b/d  
5=Zp%[#  
L>i<dD{  
for(int i=1;;i++) -.^=Z!=M  
{ ho(5r5SNE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); % d4+Ctrp-  
//Utility.log(in.readLine()); '=-s1c@^  
sHeader=httpConnection.getHeaderFieldKey(i); b^+Fs  
if(sHeader!=null) 7BVX
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{ G)4ZK#wz  
if(sHeader.equals("Content-Length")) ipgN<|`?@  
{ k`{RXx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .59KE]u  
break; K%kXS  
} oPp!*$V  
} Qs~d
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else Bi$ 0{V Z8  
break; HIQ]"Hl  
} Q>##hG:m  
} :Xh_$4~^Y  
catch(IOException e){e.printStackTrace ();} SxnIX/]J  
catch(Exception e){e.printStackTrace ();} =I %g;YK  
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Utility.log(nFileLength); +.XZK3  
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return nFileLength; 1y_fQ+\2A  
} *vRNG 3D/  
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0EcC  
//保存下载信息（文件指针位置） t$ACQ*
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private void write_nPos() tCd{G c  
{ 5@GD} oAn6  
try{ 3w[<cq.!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); bEoB;]  
output.writeInt(nStartPos.length); />2A<{6\=P  
for(int i=0;i<nStartPos.length;i++) ~W]#9&yQ  
{ \9[NH/.Z{  
// output.writeLong(nPos); HTR "m
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output.writeLong(fileSplitterFetch.nStartPos); GMVC&^  
output.writeLong(fileSplitterFetch.nEndPos); byEvc[/>Ys  
} 2V#c[%vI  
output.close(); d08`42Z69  
} pil0,r $D  
catch(IOException e){e.printStackTrace ();} r\4*\  
catch(Exception e){e.printStackTrace ();} OL,/-;z6  
} 7yc9`j}]  
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//读取保存的下载信息（文件指针位置） ]}UeuF\  
private void read_nPos() u=_b
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{ yEMX`  
try{ !D.= 'V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i}v}K'`  
int nCount = input.readInt(); 7.w*+Z>z  
nStartPos = new long[nCount]; *u:;:W&5y  
nEndPos = new long[nCount]; ;:#?~%7>  
for(int i=0;i<nStartPos.length;i++) 1(#*'xR  
{ b
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nStartPos = input.readLong(); fxLE]VJQ  
nEndPos = input.readLong(); X|lElN  
} +0oyt?  
input.close(); R=#q"9qz  
} -6hu31W  
catch(IOException e){e.printStackTrace ();} z'vdC  
catch(Exception e){e.printStackTrace ();} Tx|SAa=V  
} v^y}lT  
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private void processErrorCode(int nErrorCode) tEpIyC  
{ 1kz
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System.err.println("Error Code : " + nErrorCode); N(:EK  
} XwHu:v'=  
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c%xED%X9  
//停止文件下载 lOWB^uS%  
public void siteStop() 9^#zxmH)  
{ KZp,=[t  
bStop = true; XwKZv0ub  
for(int i=0;i<nStartPos.length;i++) J]kP`  
fileSplitterFetch.splitterStop(); tu?Z@W/  
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} :Ul'(@  
} I>YtWY|ed  
//负责部分文件的抓取 @1J51< x  
**FileSplitterFetch.java z$I[kR%I{  
*/ =,/A\F  
package NetFox; !%Z)eO~Z  
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import java.io.*; l1+w2r
d1  
import java.net.*; Q%X:5G
?  
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public class FileSplitterFetch extends Thread { |2t7G9[n  
o1p$9PL\:  
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String sURL; //File URL Hm.&f2|(  
long nStartPos; //File Snippet Start Position IDiUn!6Q  
long nEndPos; //File Snippet End Position ecSdU>  
int nThreadID; //Thread's ID .Y^d
9.  
boolean bDownOver = false; //Downing is over .NNcc4+  
boolean bStop = false; //Stop identical k vue@  
FileAccessI fileAccessI = null; //File Access interface }e/[$!35  
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9  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _Gs  
{ OxmlzQ"vM  
this.sURL = sURL; N$ qNe'b  
this.nStartPos = nStart; T
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this.nEndPos = nEnd; pZ@W6}  
nThreadID = id; /`j K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 eK=m02  
} W=;(t  
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)LMBxyS  
public void run() YQB]t=Ha  
{ QJ(e*/  
while(nStartPos < nEndPos && !bStop) Us@ {w`T  
{ [X$|dOm'N  
b
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try{ l b1sV  
URL url = new URL(sURL); [6RV'7`Abj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +*:x#$phx  
httpConnection.setRequestProperty("User-Agent","NetFox"); _I -0,  
String sProperty = "bytes="+nStartPos+"-"; 0%&fUz36E6  
httpConnection.setRequestProperty("RANGE",sProperty); 8Jib|#!  
Utility.log(sProperty); 'wT./&Z  
=xlYQ}-(a  
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InputStream input = httpConnection.getInputStream(); S8W_$=4  
//logResponseHead(httpConnection); DoCQFSL  
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byte[] b = new byte[1024]; qu#@F\gX  
int nRead; ,G!_ SZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,< )/45  
{ <=y58O]
x  
nStartPos += fileAccessI.write(b,0,nRead); 0-&sJ  
//if(nThreadID == 1) 5Ky9Pz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f-f\}G&G  
} #(7RX}  
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Utility.log("Thread " + nThreadID + " is over!"); G7kFo6Cb  
bDownOver = true; 9q0,K" x)  
//nPos = fileAccessI.write (b,0,nRead); -SC2Zgi)A  
} /O(;
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catch(Exception e){e.printStackTrace ();} 1vR#FE?  
} JG+g88  
}  ]5)&36  
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).O2_<&?F  
//打印回应的头信息 wJ]$'c3  
public void logResponseHead(HttpURLConnection con) ezq q@t9  
{ N:gstp  
for(int i=1;;i++) ]TTJrC:  
{ [(e`b  
String header=con.getHeaderFieldKey(i); U0|j^.)  
if(header!=null) m?R+Z6c[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); U}vtVvx  
Utility.log(header+" : "+con.getHeaderField(header)); (EF$^FYPK  
else I;":O"ij\  
break; omUl2C  
} ;ZqD60%\  
} CsST-qxg  
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yn ?U7`V  
public void splitterStop() !f]3Riw-=,  
{ J\,e/{,X  
bStop = true; hoD[wAC  
} .n|3A3:  
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} $Ln
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#  
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/* PRf\6   
**FileAccess.java 2Nt]Nj`  
*//文件访问(定位，写) a~N)qYL:  
package NetFox; }";hz*a  
import java.io.*; DrCfC[A~]  
nrD=[kc!w  
@S
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public class FileAccessI implements Serializable{ {Z~VO  
9787uj]Y}H  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %!hA\S  
RandomAccessFile oSavedFile; 7QL) }b.H  
long nPos; #
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qP.VK?jF|  
);.<Yf{c  
public FileAccessI() throws IOException qaSv]k.  
{ 1p5q}">z  
this("",0); 93p9?4;n-  
} Pc:'>,3!V3  
~(doy@0M  
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public FileAccessI(String sName,long nPos) throws IOException N|#x9mE  
{ V9 t:JY  
oSavedFile = new RandomAccessFile(sName,"rw"); ojs/yjvx  
this.nPos = nPos; E":":AC#  
oSavedFile.seek(nPos); k}a!lI:  
} PT*@#:MA  
+z/73s0~  
r
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public synchronized int write(byte[] b,int nStart,int nLen) UtW3KvJ#=  
{ +wgUs*(W  
int n = -1; 6 VJj(9%  
try{ ,4I6RwB.  
oSavedFile.write(b,nStart,nLen); &7y1KwfXn  
n = nLen; 9Qm{\  
} ' xq5tRg>  
catch(IOException e) `];[T=  
{ 9(Xch2tpO!  
e.printStackTrace (); Fl(ZKpSZU  
} 5TW<1'u  
$G([#N<  
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return n; HE.Dl7{  
} p.7p,CyB  
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} g<jK^\eW  
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4'eVFu+62  
/* 9 u89P  
**SiteInfoBean.java k5\ zGsol  
*/ Iz=E8R g  
package NetFox; B'~i Z65  
:z5Ibas:  
=:}DD0o*  
public class SiteInfoBean { +[nYu)puP  
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O*"wQ50Ou  
private String sSiteURL; //Site's URL %[F;TZt  
private String sFilePath; //Saved File's Path `-e}:9~q  
private String sFileName; //Saved File's Name IaqN@IlWb  
private int nSplitter; //Count of Splited Downloading File 6E%k{ r  
.:Xe*Q  
N@ tb^M  
public SiteInfoBean() ~9 nrS9)  
{//nSplitter的缺省值为5 k5<0M'  
//default value of nSplitter is 5 9CSz<[  
this("","","",5); QLLVOJi  
} Zl/+HU~  
z>#$#:Z4  
,(b~L<zN&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z?[J_[ZtR3  
{ Xst}tz62F  
sSiteURL= sURL; +K4v"7C V  
sFilePath = sPath; ^HKaNk<  
sFileName = sName; _'v )Fy  
this.nSplitter = nSpiltter; ol>=tk 8}  
6EGEwx  
3Jit2W4  
} Xq$0% WjG  
c=mFYsSv  
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public String getSSiteURL() g5]DA.&(  
{ *\5H\s9<  
return sSiteURL; blS4AQ?
b^  
} A}}t86T  
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;L{y3CWT  
public void setSSiteURL(String value) J)~=b_'<  
{ ?7dDQI7^(  
sSiteURL = value; RLr-xg$K-t  
} )7TTRL  
r+obm)Qtp  
v<4X;4p^  
public String getSFilePath() jtJU5Q  
{ O~1p]j  
return sFilePath; FiH!)6T  
} !S<~(Ujyw  
U4/$4.'
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public void setSFilePath(String value) 7E]l
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{ p#I1l2nE  
sFilePath = value; X> KsbOZ  
} 3@A k6Uh  
s;)tLJ!  
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public String getSFileName() @J)vuGS  
{ &0blHDMj{#  
return sFileName; (6aZQ`H  
} uSbg*OA  
 HuClO  
|1x,_uyQ%  
public void setSFileName(String value) @TT[H*,  
{ jV8><5C  
sFileName = value; 11'Tt!  
} 6<GWDO  
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9dv~WtH>5  
public int getNSplitter() 247>+:7z  
{ mI18A#[ 3  
return nSplitter; 8gdOQ=a  
} )HHzvGsL)  
S]{Z_|h*j  
:@L5=2Z+  
public void setNSplitter(int nCount) [O'p&j@  
{ ]YKWa"  
nSplitter = nCount; O2B$c\pw  
} r3)t5P*_  
} %dQX d]  
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@ vudeaup  
/* S^.=j oI  
**Utility.java YEj U3^@  
*/ LdL\B0^l  
package NetFox; djp(s$:{4  
 O@$i
 
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public class Utility { &kE|~i:=,9  
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public Utility() bL%)k61G_v  
{ t$2{U  
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} YKk%;U*  
_XtY/7n  
//线程睡眠 $P~a  
public static void sleep(int nSecond) NI)nf;C  
{ %mJ)pMV  
try{ T@Xi
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Thread.sleep(nSecond); +d96Z^KUhv  
} cm<3'#~Q?  
catch(Exception e) b"V-!.02  
{ m9S5;kB]  
e.printStackTrace (); gS 3&,^  
} }Q_i#e(S  
} v]>(Ps )R  
8'$n|<1X  
//日志 y.2 SHn0  
public static void log(String sMsg) N3)EG6vE*  
{ .nJGxz+X"  
System.err.println(sMsg); <Th.}=  
} Z$@Nzza-  
U# gmk0>t{  
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public static void log(int sMsg) 4a~_hkY]  
{ +{Ttv7l_2  
System.err.println(sMsg); ,q1RJiR  
} Qp}<8/BM\  
} B'yrXa|P  
4P5wEqU.<  
5Ml}m  
/* k,J?L-F  
**TestMethod.java 4{&  
*/ UWp(3FQ  
package NetFox; K[H$qJmPX  
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public class TestMethod { j~0hAKHG  
|{(ynZ]R  
b%6_LK[  
public TestMethod() FrS>.!OFn  
{ ///xx/weblogic60b2_win.exe 4T"P#)z  
try{ v?rN;KY#pK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;S/fe(C   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .W\Fa2}%av  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Om*Dy}  
fileFetch.start(); ?p]w_l  
} (Y86q\DQ?|  
catch(Exception e){e.printStackTrace ();} AiuF3`Xa  
3-0Y<++W3>  
vnE,}(M  
} 3mWN?fC  
 *hba>LZ  
sE% n=Ww  
public static void main(String[] args) rHznXME$wZ  
{ /C"E*a  
new TestMethod(); a"EXR-+8  
} MWB?V?qPSC  
} {v(3[7  
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