http断点续传简单实现（java)

/* -g;iMqh#  
**SiteFileFetch.java rbO9NRg>  
*/ _s|C0Pt  
package NetFox; WkXa%OZ  
import java.io.*; 6}n_r}kNR  
import java.net.*; R\A5f\L9  
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public class SiteFileFetch extends Thread { b0PF7PEEQ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z1T.\mzfX  
long[] nStartPos; //开始位置 p8%x@%k  
long[] nEndPos; //结束位置 QC \8Zy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 db@i*Bf  
long nFileLength; //文件长度 2e/ JFhA  
boolean bFirst = true; //是否第一次取文件 X*]uLgbl  
boolean bStop = false; //停止标志 w/~,mzM"  
File tmpFile; //文件下载的临时信息 #J)sz,)(  
DataOutputStream output; //输出到文件的输出流 TW{.qed8^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） eqZ V/a  
public SiteFileFetch(SiteInfoBean bean) throws IOException @4sv(HyDY  
{ xl5mI~n_~  
siteInfoBean = bean; pu0IhDMn  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 52C>f6w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Cc$!TZq=  
if(tmpFile.exists ()) "n}J
6  
{ (Z,v)TOXjV  
bFirst = false; yS@c2I602  
read_nPos(); vf
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} 8l~]}2LAs  
else i`z1if6O  
{ brl(7_2  
nStartPos = new long[bean.getNSplitter()]; /v U$62KA  
nEndPos = new long[bean.getNSplitter()]; vCb3Ra~L`  
} /[q6"R!uMz  
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} *Cz>r}W  
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public void run() )iNMjg  
{ ^vn8s~
#  
//获得文件长度 f-F+Y`P  
//分割文件 @i'R
IL}  
//实例FileSplitterFetch F=7X,hK  
//启动FileSplitterFetch线程 ^ |z|kc
 
//等待子线程返回 64%P}On  
try{ :1^ R$0d  
if(bFirst) b|^g51v  
{ ]JVs/  
nFileLength = getFileSize(); qjFz}6  
if(nFileLength == -1) |]1-ck!  
{ 'W(+rTFf!  
System.err.println("File Length is not known!"); )h]~< fU  
} )r3}9J  
else if(nFileLength == -2) pM],-7UM  
{ $N'AZY]4]  
System.err.println("File is not access!"); VG0Ty;bV  
} &_Ze@Ir-  
else 5\gL+qM0  
{ mFfw*,M
  
for(int i=0;i<nStartPos.length;i++) ?oana%  
{ H=Scrvfx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Q9
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} a\;1%2a  
for(int i=0;i<nEndPos.length-1;i++) sL" h  
{
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nEndPos = nStartPos[i+1]; 5b>-t#N,  
} &|yQwNA*a"  
nEndPos[nEndPos.length-1] = nFileLength; C))5,aX  
} ~A@T_*0  
} zx` %)r  
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//启动子线程 <7'`N\a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b3R1L|@  
for(int i=0;i<nStartPos.length;i++) 1 aWzd[i  
{ sB!#`kh  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <;Q1u,Mc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }L mhM  
nStartPos,nEndPos,i); #&zM.O1Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b-?wJSf|  
fileSplitterFetch.start(); paKur%2u  
} & -r^Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LLyw9y1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r-^FM~
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", UWU(6J|Fk  
nEndPos = " + nFileLength); MWdev.m:Z  
// fileSplitterFetch[nPos.length-1].start(); a8 X}r.  
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YcQ$nZAU  
//等待子线程结束 r<'ni  
//int count = 0; O
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//是否结束while循环 >+,w2m@0  
boolean breakWhile = false; ')R+Z/hG.  
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while(!bStop) ),{v  
{ q+iG:B/Z  
write_nPos(); pbCj ^  
Utility.sleep(500); B":9C'tip  
breakWhile = true; _V2^0CZ  
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for(int i=0;i<nStartPos.length;i++) mM9aT0_w  
{
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if(!fileSplitterFetch.bDownOver) $>JfLSyC  
{ ]& 8c 45c  
breakWhile = false; zA%YaekJ  
break; ]ilQq~X  
} YD3jP}Ym  
} =Bg $OX  
if(breakWhile) s5bqS'%  
break; Hs:0j$  
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{  
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//count++; e{EC#%x_  
//if(count>4) noNJ+0S  
// siteStop(); Ln'y 3~@  
} /0Jf/-}ovn  
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System.err.println("文件下载结束！"); z*a-=w0  
} Sj ly]  
catch(Exception e){e.printStackTrace ();} t[e]AU[}  
} MzFFWk  
/Nc)bF%gX  
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//获得文件长度 Y\,aJL$  
public long getFileSize() vfd<qdi3p(  
{ `q9n`h1  
int nFileLength = -1; XS}-@5TI  
try{ ;AG&QdTMh  
URL url = new URL(siteInfoBean.getSSiteURL()); J$W4AT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o)bKs>` U  
httpConnection.setRequestProperty("User-Agent","NetFox"); kwXUjnp  
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int responseCode=httpConnection.getResponseCode(); ;^TSla+t+  
if(responseCode>=400) 'fs tfk  
{ X"jL  
processErrorCode(responseCode); *rg
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return -2; //-2 represent access is error Pn,>eD*g  
} 28LBvJVq@  
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String sHeader; zcC:b4  
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for(int i=1;;i++) VbDk44X.W  
{ @Di!~e6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); gyQPQ;"H$2  
//Utility.log(in.readLine()); YQ@2p?4m  
sHeader=httpConnection.getHeaderFieldKey(i);  y!dw{Lz  
if(sHeader!=null) W}y)vrL  
{ `W>Sss  
if(sHeader.equals("Content-Length")) Bq;GO  
{ E/hT/BOPK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {!j)j6(NY
 
break; bU/4KZ'-^  
} }= wor~  
} 2FW"uYA;6  
else ]WzeJ"r {3  
break; ~F53{qxV  
} {{Qbu}/@  
} yM}3u4FG  
catch(IOException e){e.printStackTrace ();} qqJghV$Oj  
catch(Exception e){e.printStackTrace ();} F @<h:VVP  
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1 +s;a]-C  
Utility.log(nFileLength); ?(Ua+*b  
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return nFileLength; oB%_yy+  
} H0!$aO  
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//保存下载信息（文件指针位置） FW5v 1s=  
private void write_nPos() xFekSH7[F  
{ \>>P
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try{ e/_QS}OA  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FrUqfTi+W  
output.writeInt(nStartPos.length); |d z2Drc  
for(int i=0;i<nStartPos.length;i++) kh{3s:RQfC  
{ :\I*_00!  
// output.writeLong(nPos); Fw*O ciC  
output.writeLong(fileSplitterFetch.nStartPos); ij|>hQC5i  
output.writeLong(fileSplitterFetch.nEndPos); 7p hf  
} ).IyjHY  
output.close(); 2NJ\`1HZ\  
} 9pPLOXr ,  
catch(IOException e){e.printStackTrace ();} xkw=os  
catch(Exception e){e.printStackTrace ();} _si5z  
} 6bc\ )n`  
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//读取保存的下载信息（文件指针位置） }vh4ix  
private void read_nPos() a??8)=0|}  
{ }3_b%{  
try{ Ue60Mf
  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 52 Qr  
int nCount = input.readInt(); %k32:qe  
nStartPos = new long[nCount]; TTFs|T6`q  
nEndPos = new long[nCount]; 7i{(,:  
for(int i=0;i<nStartPos.length;i++) m(?{#aaq  
{ 2IE\O8b  
nStartPos = input.readLong(); {l5fKVb\C  
nEndPos = input.readLong(); N6of$p'N  
} ^e <E/j{~  
input.close(); +
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} V2`Ud[  
catch(IOException e){e.printStackTrace ();} 5-$D<}Z  
catch(Exception e){e.printStackTrace ();} '2i !RT-  
} fqY'Uq$=  
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private void processErrorCode(int nErrorCode) ~Gz9pBv1  
{ d"miPR  
System.err.println("Error Code : " + nErrorCode); 7(X z%v  
} f+hHc8g  
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//停止文件下载 c`p'5qz  
public void siteStop() Jy%?"wn  
{ mICEJ\`x  
bStop = true; Xpn\TD<_I  
for(int i=0;i<nStartPos.length;i++) ^d{5GK'  
fileSplitterFetch.splitterStop(); _p%n%Oce
 
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} [RN]?,  
} ?#xm6oe#aH  
//负责部分文件的抓取 TUC)S&bC  
**FileSplitterFetch.java [SC6{|  
*/ WEe7\bWF  
package NetFox; oC49c~`8  
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import java.io.*; `62v5d*>a  
import java.net.*; >FwK_Zd'  
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public class FileSplitterFetch extends Thread { ed#fDMXGQ%  
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String sURL; //File URL gAdqZJR%]  
long nStartPos; //File Snippet Start Position ;[R6rVHe{  
long nEndPos; //File Snippet End Position wV==sV  
int nThreadID; //Thread's ID
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boolean bDownOver = false; //Downing is over 0t^FM<7G  
boolean bStop = false; //Stop identical {<gv1Yht  
FileAccessI fileAccessI = null; //File Access interface A8vd@0  
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k Alxm{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z>g>OPu  
{ ApeqbD5g&  
this.sURL = sURL; 'Tjvq%ks
 
this.nStartPos = nStart; mXp#6'a  
this.nEndPos = nEnd; +|obU9M  
nThreadID = id; 3PU_STSix  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,.QJS6Yv  
} mW%8`$rVEO  
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public void run() K$h\<_V  
{ Dc-K08c  
while(nStartPos < nEndPos && !bStop) dE_Xd:>  
{ F&czD;F  
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try{ r9_ ON|  
URL url = new URL(sURL); M.mn9kw`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `w:kY9  
httpConnection.setRequestProperty("User-Agent","NetFox"); I!Z`'1"  
String sProperty = "bytes="+nStartPos+"-"; F*PhV|XU  
httpConnection.setRequestProperty("RANGE",sProperty); CLaQE{  
Utility.log(sProperty); ?lsK?>uU  
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InputStream input = httpConnection.getInputStream(); /\/^= j  
//logResponseHead(httpConnection); ,]2?S5R  
r/!,((Z\  
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byte[] b = new byte[1024]; ~o^|>]  
int nRead; bN. G%1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G)?*BH  
{ dw<i)P^   
nStartPos += fileAccessI.write(b,0,nRead); cRnDAn#42  
//if(nThreadID == 1) .pUB.l$)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NlEyT9  
} f1_;da  
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Utility.log("Thread " + nThreadID + " is over!"); ;]-08lzO<4  
bDownOver = true; 3$!QP N  
//nPos = fileAccessI.write (b,0,nRead); :.+w'SEn4M  
} y]jx-wc3O  
catch(Exception e){e.printStackTrace ();} *m"9F'(Sd  
} hH1Q:}a  
} 
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_VT{2`|})  
;-u]@35  
//打印回应的头信息 FS
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public void logResponseHead(HttpURLConnection con) }+KM"+@$<  
{ 9A.NM+u7  
for(int i=1;;i++) e`4mrBtz|  
{ /+92DV  
String header=con.getHeaderFieldKey(i); FAnz0p+t  
if(header!=null) mw
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); QlGK+I>y;  
Utility.log(header+" : "+con.getHeaderField(header)); F-3=eKZ  
else 8`*5[ L~~/  
break; u<:uL  
} 4~Cf_`X}]  
} ExO#V9DaW  
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public void splitterStop() D=a*Xu2zq  
{ 5>9Q<*  
bStop = true; E^rBs2;9
  
} >V(C>^%->  
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} r!!uA1!7  
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/* Lmjd,t  
**FileAccess.java VDnrm*  
*//文件访问(定位，写) }` 3-  
package NetFox; WDY\
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import java.io.*; =r/K#hOR\J  
)$^xbC#j`3  
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public class FileAccessI implements Serializable{ PNAvT$0LaZ  
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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 AIOGa<^  
RandomAccessFile oSavedFile; l#cVQ_^"  
long nPos; On);SN'  
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public FileAccessI() throws IOException x}a
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{ Z|@-=S(.  
this("",0); :gRrM)n  
} ;,U@zB;\%(  
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public FileAccessI(String sName,long nPos) throws IOException 1<@lM8&.kO  
{ S3x^#83  
oSavedFile = new RandomAccessFile(sName,"rw"); }%w;@[@L  
this.nPos = nPos; {0j,U\ kb  
oSavedFile.seek(nPos); i/!{k2  
} 0*:n<T9  

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public synchronized int write(byte[] b,int nStart,int nLen) L`M{bRl+1  
{ 1Mq"f7X8  
int n = -1; ?z)
2\D  
try{ %zc.b  
oSavedFile.write(b,nStart,nLen); OtL~NTY  
n = nLen; ~*h)`uM  
} 8u[.s`^  
catch(IOException e) ,%m~OB#  
{ :fX61S6)  
e.printStackTrace (); fC^d@4ha  
} Pi[]k]XA\  
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return n; w2 (}pz:  
} ,f>^q"  
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} 4myikeUR_  
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;,/G*`81B  
/* 6UN{Vjr%`  
**SiteInfoBean.java tm34Z''.>  
*/ Y,n8co^  
package NetFox; \8Ewl|"N:u  
=*4^Dtp  
JKYtBXOl  
public class SiteInfoBean { r+]a  
|<]wM(GxE  
|[V6R\l39  
private String sSiteURL; //Site's URL pdQaVe7tRo  
private String sFilePath; //Saved File's Path >SZuN"r8`  
private String sFileName; //Saved File's Name R$/q=*k  
private int nSplitter; //Count of Splited Downloading File ;rh=63g  
>hnhV6ss  
@ bvWqMa  
public SiteInfoBean() m&*0<N  
{//nSplitter的缺省值为5 }/xdHt  
//default value of nSplitter is 5 z1e+Ob&  
this("","","",5); $H,9GIivD  
} Q>=/u-  
&6Wim<*  
$iy(+}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \<=.J`o{  
{ ]w8h#p  
sSiteURL= sURL; ]_y;Igaj  
sFilePath = sPath; >vf
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sFileName = sName; w/0;N`YB  
this.nSplitter = nSpiltter; k"`^vV[{F  
8/9YR(H3H  
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} 'xOH~RlE
 
\ ]h$8JwV  
6`'KM/  
public String getSSiteURL() xiQd[[(sM  
{ mc6W"  
return sSiteURL; .O4=[wE!U  
} na/,1iI<  
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public void setSSiteURL(String value) QRY7ck:N  
{ +m6acu)N.  
sSiteURL = value; 4kLTKm:G  
}
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qQ<7+z<4KP  
3DrW[\  
public String getSFilePath() 8x6{[Tx   
{ NEM
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return sFilePath; Q"{Q]IT  
} EG!):P  
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public void setSFilePath(String value) 1\Vp[^
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{ ^F$iD (f  
sFilePath = value; E@ !~q  
} 8J#TP7;  
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:j!N7c{  
public String getSFileName() 
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{ so\8.(7n  
return sFileName; V}"w8i+D?  
} ]a=Bc~g91  
0\^K\J,.  
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public void setSFileName(String value) ,1-#Z"~c  
{ fxk6q$'  
sFileName = value; syLpnNx=  
}
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erZ%C <  
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public int getNSplitter() ~C2[5r{So  
{ l
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return nSplitter; ) bGzsb1\  
} '@+a]kCMev  
0E#3XhU  
.EQ1r7 9,  
public void setNSplitter(int nCount) ~,.}@XlgT.  
{ u9%)_Q!14  
nSplitter = nCount; ,=kQJ|  
} LK[%}2me  
} BPzlt  
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/* p
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**Utility.java FsYsQ_,R3  
*/ D#,P-0+%  
package NetFox; Xz, sL  
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public class Utility { f}>S"fFI  
7EAkY`Op  
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public Utility() n7S~nk  
{ 0vRug|}k#%  
&N!;d E  
+wwK#ocw  
} a~F`{(Q2  
<v)Ai;l,  
//线程睡眠 c|'hs  
public static void sleep(int nSecond) `n!<h,S'2  
{ LAwl9YnG:  
try{ A,T3%TE  
Thread.sleep(nSecond); -l!;PV S|  
} v&EHp{8Qd  
catch(Exception e) kOGpe'bV  
{ QxmVImn"  
e.printStackTrace (); 3'WS6B+  
} q)uq?sZe  
} 0r+%5}|-K  
(Js'(tBhiU  
//日志 m"!!)
 
public static void log(String sMsg) ,&sBa{0  
{ Z=Oo%lM6B  
System.err.println(sMsg); 24Y~x`W   
} RJ%~=D  
{qm(Z+wcmb  
uL!{xuN  
public static void log(int sMsg) MOFIR wVZ+  
{ yS#LT3>l  
System.err.println(sMsg); [Uezi1
I  
} sYt8NsQ  
} o(. PxcD  
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]y,6  
/* 7 3k3(r
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**TestMethod.java _AQ :<0/#  
*/ Zjt3U;Y
 
package NetFox; '(kySf[  
MS6^= ["  
$H/3t?6h`  
public class TestMethod { /0 ,#c2aq  
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public TestMethod() UKx91a}g  
{ ///xx/weblogic60b2_win.exe o_<o8!]l"  
try{ 6ZVJ2xs[%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); laqW {sX^5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -\j}le6;c  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?0+D1w  
fileFetch.start(); 5isejR{r  
} Jjz:-Uqq2  
catch(Exception e){e.printStackTrace ();} +"a .,-f!  
9q;\;-  
2-u>=r0L  
} NrTQ}_3)  
fAfsKO*  
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public static void main(String[] args) z@$7T:H>  
{ jGEUl=W  
new TestMethod(); l?B\TA^  
} jjkiic+tDN  
} -ny[Lh^b  
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