http断点续传简单实现（java)

/* p"dK,A5#)  
**SiteFileFetch.java b%TLvV 9F  
*/ c$fYK  
package NetFox; 2R`dyg  
import java.io.*; -Pt']07E  
import java.net.*; RG8Ek"D@  
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public class SiteFileFetch extends Thread { ,7/F?!G!J  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ytyX:e"  
long[] nStartPos; //开始位置 P
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long[] nEndPos; //结束位置 isR)^fI|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 v?L
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long nFileLength; //文件长度 U{Xx)l/o  
boolean bFirst = true; //是否第一次取文件 = lMs1}S9  
boolean bStop = false; //停止标志 N]|P||fC  
File tmpFile; //文件下载的临时信息 AM:
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DataOutputStream output; //输出到文件的输出流 xsERnF>`  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *>,#'C2  
public SiteFileFetch(SiteInfoBean bean) throws IOException Z[GeU>?P  
{ 5<77o|  
siteInfoBean = bean; KM9)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *Z}9S9YtN  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nsjrzO79L8  
if(tmpFile.exists ()) k.6gX<T  
{ mhi^zHpa  
bFirst = false; sIz*r Gz  
read_nPos(); EHlkt,h*  
} =C4!h'hz  
else C#oH7o+_.  
{ 5tUN'KEbN  
nStartPos = new long[bean.getNSplitter()]; %|o2d&i  
nEndPos = new long[bean.getNSplitter()]; 8-geBlCE,  
} 5~H}%W,P  
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} P~9y}7Q\0  
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public void run() jA,|.P>  
{ C|g]Y 7  
//获得文件长度 Jj'dg6QY'  
//分割文件 jr3FDd]  
//实例FileSplitterFetch b75en{aDi*  
//启动FileSplitterFetch线程 D"ecwx{%;C  
//等待子线程返回 "]kq,j^]  
try{ bSm*/Q  
if(bFirst) Cp!Qd e  
{ 7 P/1'f3  
nFileLength = getFileSize(); ZB'ms[  
if(nFileLength == -1) S*Hv2
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{ K
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System.err.println("File Length is not known!"); )2g-{cYv  
} R$M>[Kjn  
else if(nFileLength == -2) th]pqhl>  
{ }:xj%?ki  
System.err.println("File is not access!"); x2$Y"b?vz  
} MgrJ ;?L  
else 7&Qf))L  
{ GSaU:A
 
for(int i=0;i<nStartPos.length;i++) .:A&5Y-  
{ t(r}jU=qw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p)YI8nW  
} HE.YfD)  
for(int i=0;i<nEndPos.length-1;i++) |0s)aV|K  
{ bX'.hHR  
nEndPos = nStartPos[i+1]; n"|1A..^  
} mj|TWDcj+  
nEndPos[nEndPos.length-1] = nFileLength; SE0&CV4  
}
i_ z4;%#?  
} h$2lO^  
{/Qg4pc!  
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//启动子线程 g;._Q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C~q&  
for(int i=0;i<nStartPos.length;i++) 9Pjw<xt  
{ !6pE0(V^+4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L`n Ma  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bY!1t}ALh  
nStartPos,nEndPos,i); L)-1( e<x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TV[@
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fileSplitterFetch.start(); H?$gHZPI  
} (GB*+@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %}1v-z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ||o :A  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0;SRmj@W  
nEndPos = " + nFileLength); VB&`g<  
// fileSplitterFetch[nPos.length-1].start(); D!5{CQl  
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3R)_'!R[B  
//等待子线程结束 \>lDM  
//int count = 0; ]mdO3P  
//是否结束while循环 ?CO..l  
boolean breakWhile = false; D'Y=}I)8Dn  
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*z6m644H  
while(!bStop) T
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{ rJUXIV>z  
write_nPos(); Io\tZXB  
Utility.sleep(500); Q@5v> `  
breakWhile = true; i;I!Jc_b'  
hjx=?  
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for(int i=0;i<nStartPos.length;i++) K</="3 HK  
{ &T2qi'  
if(!fileSplitterFetch.bDownOver) EU4j'1!&g<  
{ g ^4<ve  
breakWhile = false; d8%sGH  
break; 'RzzLk|$  
} }Sv\$h  
} HsRQiai*  
if(breakWhile) &09g0K66  
break; !lk9U^wnd  
,*j@Zb_r  
/6yH ,{(a  
//count++; 'm|PSwB7  
//if(count>4) z\r29IRh  
// siteStop(); =x5k5NIF  
} SJ).L.Cm6  
:!<U"AC  
ZDTp/5=?K/  
System.err.println("文件下载结束！"); xY$@^(Q\  
} U~s-'-C/  
catch(Exception e){e.printStackTrace ();} sQgJ`+Y8_  
} DxJY{e9  
B(qwTz 51  
!B:wzb_  
//获得文件长度 h[}e5A]}  
public long getFileSize() YW'l),Z  
{ TT3\c,cs  
int nFileLength = -1; -,^Z5N#\|  
try{ `PI?RU[g*  
URL url = new URL(siteInfoBean.getSSiteURL()); [28Vf"#]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8Q\ T,C  
httpConnection.setRequestProperty("User-Agent","NetFox"); :<i<\TH'  
08F~6
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int responseCode=httpConnection.getResponseCode(); >@?`n}r|  
if(responseCode>=400) RE.t<VasP  
{ C[Nh>V7=  
processErrorCode(responseCode); \3 M%vJ  
return -2; //-2 represent access is error 26[m7\O  
} ;QqC c!b  
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}E&48$0h  
String sHeader; MVOWJaT(Aq  
-i*]Sgese  
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for(int i=1;;i++) MoMxKmI  
{ WI\jm&H r  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $[{YE[a  
//Utility.log(in.readLine()); 7Kn}KO!Y8  
sHeader=httpConnection.getHeaderFieldKey(i); CjZIBMGc  
if(sHeader!=null) ) $=!e%{  
{ j+NsNIJq  
if(sHeader.equals("Content-Length")) a}5/?/  
{ VkZ3Q7d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));  re@;6o  
break; EN;4EC7tE  
} "eZ~]m}L0  
} UB3hC`N\  
else \CVrLn;}  
break; cs0rz= ZdH  
} \<Di|X1  
} ` 3h,Cy^  
catch(IOException e){e.printStackTrace ();} "T1A$DKw+R  
catch(Exception e){e.printStackTrace ();} OXD*ZKi8  
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}
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Utility.log(nFileLength); =H/
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return nFileLength; Bnh*;J0  
} P`OZoI$bV  
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-$ha@bCWO  
//保存下载信息（文件指针位置） UaXWHCm`  
private void write_nPos() CM4#Nn=i~  
{ !;E{D  
try{ lc\%7
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ?v}S9z  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) O~D]C  
{ grTwo  
// output.writeLong(nPos); !]l;n Fd  
output.writeLong(fileSplitterFetch.nStartPos); g4}K6)@  
output.writeLong(fileSplitterFetch.nEndPos); Nc:0opPM  
} OEhDRU%k  
output.close(); A}G>JL  
} *_/n$& I%&  
catch(IOException e){e.printStackTrace ();} a3C\?5  
catch(Exception e){e.printStackTrace ();} *nlDN4Y[  
} _6]c f!H  
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//读取保存的下载信息（文件指针位置） DT3koci(  
private void read_nPos() BoP,MpF  
{ Oj#/R?%,X  
try{ |Pq z0n=v  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); vBYk"a6SD  
int nCount = input.readInt(); >(C5&3^  
nStartPos = new long[nCount]; v%;Nyab6$  
nEndPos = new long[nCount]; FZx.Yuv  
for(int i=0;i<nStartPos.length;i++) W
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{ gp NAM"  
nStartPos = input.readLong(); 2 sK\.yS  
nEndPos = input.readLong(); AYv7-!Yk  
} ^ wb9n  
input.close(); `qhZZ{s)1U  
} @o>3 Bv.  
catch(IOException e){e.printStackTrace ();} +l
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catch(Exception e){e.printStackTrace ();} b]
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} ?<U">8cP  
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private void processErrorCode(int nErrorCode) S=qx,<J 39  
{ 2>/}-a  
System.err.println("Error Code : " + nErrorCode); q@XxCP]  
} V=)' CCi{  
sZI$t L<j  
$PFE>=nM  
//停止文件下载 =i>i,>bv  
public void siteStop() !#dp[,nk  
{ ?u~?:a@K  
bStop = true; @P/6NMjZ^  
for(int i=0;i<nStartPos.length;i++) Vr hd\  
fileSplitterFetch.splitterStop(); `Hd~H  
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} Lc_cB`  
} );d"gv(]D  
//负责部分文件的抓取 4rUOk"li  
**FileSplitterFetch.java aRcVoOq  
*/ 0gH;y+\=*  
package NetFox; Y7<
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#sM*<2vj  
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import java.io.*; K[l5=)G0L  
import java.net.*; nx
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public class FileSplitterFetch extends Thread { > *soc!#Y  
}-~LXL%!3  
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String sURL; //File URL S#nW )=   
long nStartPos; //File Snippet Start Position qe|U*K 2_  
long nEndPos; //File Snippet End Position i!yE#z
ew  
int nThreadID; //Thread's ID $Z<x r  
boolean bDownOver = false; //Downing is over f"t+r /d  
boolean bStop = false; //Stop identical L u1pxL  
FileAccessI fileAccessI = null; //File Access interface 96i#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f0 kz:sZ9  
{ 75;g|+  
this.sURL = sURL; Nf%/)Tk  
this.nStartPos = nStart; mX[J15  
this.nEndPos = nEnd; {_UOS8j7  
nThreadID = id; e*M-y C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,O_iSohS  
} aUq2$lw1  
+aN"*//i  
! =*k+gpF  
public void run() gjk;An  
{ vsJM[$RF  
while(nStartPos < nEndPos && !bStop) VcLzv{  
{ \i3)/sZ?l  
j+("4b'  
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try{ >1$Vh=\OI  
URL url = new URL(sURL); 'cA(-ghY/E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P
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httpConnection.setRequestProperty("User-Agent","NetFox"); 'oF XNO  
String sProperty = "bytes="+nStartPos+"-"; f<M!L>+M6  
httpConnection.setRequestProperty("RANGE",sProperty); fWyXy%Qq  
Utility.log(sProperty); * 'Bu-
1{  
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3 J5
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InputStream input = httpConnection.getInputStream(); =3dd1n;8>  
//logResponseHead(httpConnection); /Ow@CB  
f dJ<(i]7W  
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byte[] b = new byte[1024]; Z=oGyA  
int nRead; ]q/USVj{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o{3>n"\w3  
{ OoQLR  
nStartPos += fileAccessI.write(b,0,nRead); 9-!GYa'Z  
//if(nThreadID == 1) yB|1?L#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  F |aLF{  
} !C ZFbz~:  
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Utility.log("Thread " + nThreadID + " is over!"); e-#Vs{?|r  
bDownOver = true; /@&#U bN\  
//nPos = fileAccessI.write (b,0,nRead); |,tKw4  
} a%5/Oc[[  
catch(Exception e){e.printStackTrace ();} qB3E  
} jZ''0Lclpc  
} /0Mt-8[  
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\  
[Y.=bfV!  
//打印回应的头信息 e'->Sg  
public void logResponseHead(HttpURLConnection con) GP;N1/=  
{ FH%M5RD  
for(int i=1;;i++) z\$(@:{A  
{ H4$f+  
String header=con.getHeaderFieldKey(i); r1 b"ta  
if(header!=null) FIUQQQ\3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zbgGK7  
Utility.log(header+" : "+con.getHeaderField(header)); ]E6r)C  
else x"r,l/gzy  
break; =}YX I  
} wN

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} j4u ["O3  
| ^G38  
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public void splitterStop() >`p?
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{ MGY0^6yK5  
bStop = true; zO@>)@~  
} 3R-5&!i  
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} 7C R6ew~  
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2[qoqd(  
/* E^$8nqCL:  
**FileAccess.java =T\=,B  
*//文件访问(定位，写) O<E8,MCA[a  
package NetFox; .(3ec/i4CF  
import java.io.*; tG ZMIG_  
vPc*x5w-  
{ {:Fs  
public class FileAccessI implements Serializable{ p_X{'=SQ1  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {&UA60~6  
RandomAccessFile oSavedFile; -m@PqJF^  
long nPos; LNyrIk/1  
`oH4"9&]k3  
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public FileAccessI() throws IOException -/V(Z+dj  
{ .FC+  
this("",0); {f@Q&(g  
} r/HTkXs I  
^9]iUx  
U|VL+9#hd  
public FileAccessI(String sName,long nPos) throws IOException 6q>}M  
{ vZ811U~}  
oSavedFile = new RandomAccessFile(sName,"rw"); ir"t@"Y;o  
this.nPos = nPos;
'&dT  
oSavedFile.seek(nPos); p$qk\efv*4  
} YB<nz<;JR  
EwkSUA>Tm  
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public synchronized int write(byte[] b,int nStart,int nLen) g(;OUkj$Zp  
{ +:4>4=  
int n = -1; 6>oc,=MV/  
try{ ^L)TfI_n  
oSavedFile.write(b,nStart,nLen); T&+3Xi:  
n = nLen; DBL@Mp[<  
} d9BFeq8  
catch(IOException e) o-7{\%+M  
{ yNowhh
 
e.printStackTrace (); Z"%.  
} euVDrJ^  
2[HPU M2>  
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return n; T^(W _S  
} JJ%@m;~  
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} `[g$EXX  
ES AX}uF  
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/* ybw\^t  
**SiteInfoBean.java  Pd\4hy  
*/ DXI4DM"15I  
package NetFox; E;{RNf|  
.P aDR |!  
f? @Qt<+k  
public class SiteInfoBean { \)rMC]  
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s_XCKhN:  
private String sSiteURL; //Site's URL `Wg"m~l$N  
private String sFilePath; //Saved File's Path 'jfE?n
gt  
private String sFileName; //Saved File's Name 6PYt>r&TO  
private int nSplitter; //Count of Splited Downloading File l<GN<[/.+  
#UoFU{6tM  
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public SiteInfoBean() UMe?nAC  
{//nSplitter的缺省值为5 sTl^j gV7j  
//default value of nSplitter is 5 t;6<k7h  
this("","","",5); "aF2:E'  
} F |BY]{  
Q=Mv"~2>B  
~`FRU/@r  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {VW\EOPV~  
{ &q
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sSiteURL= sURL; oI/_
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sFilePath = sPath; ][jwy-Uy;  
sFileName = sName; ;_c&J&I  
this.nSplitter = nSpiltter; =VzJ>!0  
j \jMN*dmV  
hmGlGc,lf  
} Ye&/O<G'V  
\-pwA j?  
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public String getSSiteURL() r=0PW_r:  
{ t!Cz;ajNi  
return sSiteURL; Ie/_gz^  
} t3Gy *B  
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6E-eD\?I&  
public void setSSiteURL(String value) JCnHEH
 
{ O}zHkcL  
sSiteURL = value; o#\L4P(J  
} 4 H0rS'5d  
+_J@8k  
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public String getSFilePath() -Yse^(^"s  
{ xOKJOl
 
return sFilePath; ocWl]h].  
} a<q9~QS  
,--#3+]XU  
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public void setSFilePath(String value)
@y7KP$t  
{ IC'+{3.m8  
sFilePath = value; Ft11?D B  
} S/)),~`4  
9;v3 (U+:  
<Hr<QiAK  
public String getSFileName() #1E4 R}B  
{ gi,7X\`KQ  
return sFileName; -d'FKOD  
} 3]?='Qq.(  
!AE;s}v)0{  
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public void setSFileName(String value) JseKqJ?g  
{ aUZ?Ue9l>2  
sFileName = value; a5/, O4Q  
} #Mn?Nn  
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onSt%5{P%X  
public int getNSplitter() ?wG  
{ i /[{xRXiR  
return nSplitter; z3i`O La  
} Yv]vl6<  
VVch%  
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public void setNSplitter(int nCount) WLXt@dK*u  
{ XLpn3sX$  
nSplitter = nCount; siCi+Y  
} *uRDB9#9,  
} E*5aLT5!,  
* cW%Q@lit  
2QbKh)  
/* eR5q3E/;G  
**Utility.java eC"e v5v  
*/ 9_5>MmiB  
package NetFox; m}?jU  
#Y7iJPO  
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public class Utility { faRQj:R8  
?GNRab  
9)vU/fJ|  
public Utility() ]I,&Bme  
{ :j3'+%'2  
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} _@XueNU1hS  
)?SF
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//线程睡眠 *(yw6(9%  
public static void sleep(int nSecond) HLDv{G'7  
{ N*Q*>q  
try{ !%t@wQ]\hG  
Thread.sleep(nSecond); `;}qj
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} 8BAe6-*S8  
catch(Exception e) s-Gd{=%/q  
{ oe^JDb#  
e.printStackTrace (); n Yx[9HN  
} 83V\O_7j  
} #pAN   
>qy62:co  
//日志 Szu@{lpP@  
public static void log(String sMsg) 5g-1pzP9  
{ l^bak]9 1  
System.err.println(sMsg); *y<eK0  
} <ndY6n3  
J)Yz@0#T(;  
9s5s;ntz"  
public static void log(int sMsg) nnRb  
{ [AFR \{  
System.err.println(sMsg); Xmmj.ZUr  
} x4kQGe(  
} ]lGkZyUhI  
NKFeND  
<Af&Q0J  
/* ] rqx><!  
**TestMethod.java ~P}ng{x4z  
*/ cy6YajOk7  
package NetFox; 9 AD*  
P*;[&Nn4  
9wfE^E1  
public class TestMethod { ?Mo)&,__  
= =pQ V[  
)g8Kicox5  
public TestMethod() $HOe){G  
{ ///xx/weblogic60b2_win.exe Q$p3cepsK  
try{ ;8MQ'#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )Dhx6xM[a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); voRb>xF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); g51UIN]o-  
fileFetch.start(); Zp{K_ec{  
} B)DuikV.D  
catch(Exception e){e.printStackTrace ();} nvQX)Xf  
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} c]k+ Sx&}  
HI:
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public static void main(String[] args) s."N7F  
{ %b_0l<+  
new TestMethod(); 2H8\P+  
} cna%;f.  
} M).CyY;bm  
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