http断点续传简单实现（java)

/* EQ]>^VE2B  
**SiteFileFetch.java ySHpN>U  
*/ (-xVW#39  
package NetFox; iy|;xBI,  
import java.io.*; `NfwW
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import java.net.*; JA% y{Wb  
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public class SiteFileFetch extends Thread { 0{/
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SiteInfoBean siteInfoBean = null; //文件信息Bean hPuF:iiQ4  
long[] nStartPos; //开始位置 a:KL{e[  
long[] nEndPos; //结束位置 zEh&@{u?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `
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long nFileLength; //文件长度 `yh][gqVE~  
boolean bFirst = true; //是否第一次取文件 q8MyEoc:n  
boolean bStop = false; //停止标志 3gYtu-1  
File tmpFile; //文件下载的临时信息 <?h(Dchq  
DataOutputStream output; //输出到文件的输出流 1n[wk'}qf4  
-@Z9h)G|  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {4*5Z[  
public SiteFileFetch(SiteInfoBean bean) throws IOException ' pIC~  
{
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siteInfoBean = bean; f8-~&N/_R  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,6ae='=d  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); h-fm)1S_  
if(tmpFile.exists ()) }\1V%c  
{ Nz:p(
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bFirst = false; :s1.TQ;Y(  
read_nPos(); eQ,VK`7X  
} qB+OxyT&  
else 'sTc=*p/  
{ \F
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nStartPos = new long[bean.getNSplitter()]; _&[-< cu  
nEndPos = new long[bean.getNSplitter()]; %qEp{i
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} rNICK2Ah  
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} >^SQrB  
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public void run() iFZ.a.NDc  
{ OS1f}<  
//获得文件长度 _-2;!L#/  
//分割文件 !wC( ]Y  
//实例FileSplitterFetch /T2 v`Li  
//启动FileSplitterFetch线程 ExF6y#Y G<  
//等待子线程返回 8:2Vib$  
try{ uX6p^KNm5  
if(bFirst) *VUJ);7k  
{ JW"`i   
nFileLength = getFileSize(); }GHCu
 
if(nFileLength == -1) /J9Or{#r  
{ 0IZF%`  
System.err.println("File Length is not known!"); >h.HW  
} A@-U#UvN  
else if(nFileLength == -2) @'y
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{ Df$~=A}  
System.err.println("File is not access!"); s[VYd:}se  
} w|NId,#f  
else 0QyL}y2  
{ *;Cpz[N  
for(int i=0;i<nStartPos.length;i++) @z:E]O}  
{ L uW""P/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Ucz=\dO1  
} uMRzUK`QK  
for(int i=0;i<nEndPos.length-1;i++) 40z1Qkmaey  
{ ,W;|K 5  
nEndPos = nStartPos[i+1]; Bn.5ivF3  
} \jZ)r>US"  
nEndPos[nEndPos.length-1] = nFileLength; 24wr=5p]Q  
} K[x=knFO   
} KOoV'YSC[(  
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tKds|0,j|  
//启动子线程 CWJ
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f{uS  
for(int i=0;i<nStartPos.length;i++) 4vNH"72P  
{ wFjQ1
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gSf>+|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4J?\JcGs  
nStartPos,nEndPos,i); /2MZ
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8~T=p:z'  
fileSplitterFetch.start(); ?y__ V
rw  
} tI5*0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Mb45UG#2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); EVE"F'Ww,_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &.PAIe.  
nEndPos = " + nFileLength); c=
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// fileSplitterFetch[nPos.length-1].start(); BqDsf5}jpA  
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//等待子线程结束 F`,Hf Cb\  
//int count = 0; Nq|y\3]  
//是否结束while循环 `?f<hIJoz  
boolean breakWhile = false; M1T.  
m"6K_4r]  
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while(!bStop) Bwu?DK  
{ IkxoW:L  
write_nPos(); Ocn@JOg  
Utility.sleep(500); qEVpkvEq  
breakWhile = true; +}Mm5^6*  
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for(int i=0;i<nStartPos.length;i++) ` k(Q:  
{ nc1?c1s,f  
if(!fileSplitterFetch.bDownOver)  t~BWN  
{ vsQvJDna~  
breakWhile = false; CrG!8}  
break; J25/Iy*byG  
} *SlWA)9Y  
} D-O{/  
if(breakWhile) ZI8@ 6L\  
break; /!y;h-  
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//count++; Ps;4]=c  
//if(count>4) )-Z*/uF^  
// siteStop(); Y kvEQ=  
} xMa9o  
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System.err.println("文件下载结束！"); k_?~@G[I  
} %(H' j@D[  
catch(Exception e){e.printStackTrace ();} ^NM>xIenf  
} &>R:oYN  
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7|"$YV'DM  
//获得文件长度 ed`7GZB  
public long getFileSize() L$@+'Qn@:  
{ .[s6PzQy  
int nFileLength = -1; 52^,qP'6  
try{ 1]vDM&9  
URL url = new URL(siteInfoBean.getSSiteURL()); Q'?VLv|@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $ f||!g  
httpConnection.setRequestProperty("User-Agent","NetFox"); gvL*]U7  
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int responseCode=httpConnection.getResponseCode(); JXR]G  
if(responseCode>=400) x}=Q)|)]  
{ WM4,\$  
processErrorCode(responseCode); |KO[[4b ?+  
return -2; //-2 represent access is error oa[O~z{~  
} "?FBbJ  
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+}:2DXy@  
String sHeader; I|;C}lfp  
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for(int i=1;;i++) IGab~`c-[  
{ DJqJ6z:'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2MW7nIEs  
//Utility.log(in.readLine()); MmFtG-  
sHeader=httpConnection.getHeaderFieldKey(i); #&?}h)Jr'  
if(sHeader!=null) LlVbY=EX7  
{ {<#b@=G  
if(sHeader.equals("Content-Length")) jE8}Ho_#)  
{ Vs Z7n~e  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]86*k%A  
break; H\a\xCP3  
} :)kHXOb.  
} '+'h^
 
else @hrIu"
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break; OI3j!L2f  
} OKk"S_`  
} aSgKh  
catch(IOException e){e.printStackTrace ();} vj]h[=:  
catch(Exception e){e.printStackTrace ();} .'h^  
/;!I.|j  
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Utility.log(nFileLength); Prc1U)nfo  
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return nFileLength; $@L2zl1  
} 1=`VaS  
+oHbAPs8  
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//保存下载信息（文件指针位置）  .C5JQO  
private void write_nPos() xDsKb_  
{ uyWw3>  
try{ oMOh4NH,x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _j*I\  
output.writeInt(nStartPos.length); xVN!w\0  
for(int i=0;i<nStartPos.length;i++) 3Wx\Liw,  
{ :JZV=@<T  
// output.writeLong(nPos); CC3M7|eO3  
output.writeLong(fileSplitterFetch.nStartPos); \+0l#t$  
output.writeLong(fileSplitterFetch.nEndPos); BHErc\ITP  
} }OTJ{eG  
output.close(); z2!4w +2  
} BN&}g}N  
catch(IOException e){e.printStackTrace ();} |ZXz&Xor  
catch(Exception e){e.printStackTrace ();} "=JE12=u  
} !\O!Du  
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//读取保存的下载信息（文件指针位置） mgM"u94-]
 
private void read_nPos() oTcf[<  
{ L]&y[/\E1  
try{ ;d_<6|*M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "/2kf)l{4  
int nCount = input.readInt(); 2iO{*cB
 
nStartPos = new long[nCount]; hb
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nEndPos = new long[nCount]; y9=<q%Kc-  
for(int i=0;i<nStartPos.length;i++) K8_\U0 K  
{ e~cg (.  
nStartPos = input.readLong(); VWzuV&;P  
nEndPos = input.readLong(); b):aqRwP  
} ;18u02z^  
input.close(); tF./Jx]_  
} 9\=SG"e(  
catch(IOException e){e.printStackTrace ();} cqW(9A|8  
catch(Exception e){e.printStackTrace ();} UnEgsfN  
} !41"`D!1  
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private void processErrorCode(int nErrorCode) dO,;k+  
{ gr{*wYL  
System.err.println("Error Code : " + nErrorCode); Np+pJc1  
} uY/CiTWr  
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|YfJ#Agm+  
//停止文件下载 ?[Ma" l>  
public void siteStop() 6:`[Fi  
{ GhjqStjS&l  
bStop = true; {K?e6-N(z  
for(int i=0;i<nStartPos.length;i++) >J)4e~9EJ2  
fileSplitterFetch.splitterStop(); qElPYN*wF  
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} 6K=}n] n  
} D]|{xKC}  
//负责部分文件的抓取 -z se+]O`  
**FileSplitterFetch.java UFUEY/q  
*/ zAJC-YC6  
package NetFox; p<wC{D  
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import java.io.*; S-</(,E}|  
import java.net.*; q9a6s{,  
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public class FileSplitterFetch extends Thread { nNnfcA&W  
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String sURL; //File URL ,Tk53"  
long nStartPos; //File Snippet Start Position zqZ/z>Gf  
long nEndPos; //File Snippet End Position NmF8BmIj  
int nThreadID; //Thread's ID 2 &_>2"=<@  
boolean bDownOver = false; //Downing is over &fU48n1Uh  
boolean bStop = false; //Stop identical NS*Lv  
FileAccessI fileAccessI = null; //File Access interface YQD/vc~8G  
~@[<y1g?nG  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !67xN?b  
{ \b$Y_  
this.sURL = sURL; GJHJ?^%  
this.nStartPos = nStart; ^),t=!;p  
this.nEndPos = nEnd; YRd`G3J  
nThreadID = id; ez5>V7Y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 yMD0Tj5ZQ  
} /V#?d  
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public void run() E0DquVrz  
{ giW9b_  
while(nStartPos < nEndPos && !bStop) =U8+1b  
{ )a`kL,  
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try{ K*4ib/'E a  
URL url = new URL(sURL); ]&P 4QT)f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *Ue#Sade  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2:e7'}\D.  
String sProperty = "bytes="+nStartPos+"-"; b' ~WS4xlD  
httpConnection.setRequestProperty("RANGE",sProperty); .0;\cv4}  
Utility.log(sProperty); 5 [4{1v  
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InputStream input = httpConnection.getInputStream(); Q|2*V1"r<2  
//logResponseHead(httpConnection); t"e%'dFv  
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byte[] b = new byte[1024]; OIjG`~Rx  
int nRead; L&uPNcZ`-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _?$w8 S%  
{ 0(&Rm
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nStartPos += fileAccessI.write(b,0,nRead); a( N;|<  
//if(nThreadID == 1) @uG/2'
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c%+uji6  
} 78?cCj{e  
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Utility.log("Thread " + nThreadID + " is over!"); X gtn}7N.  
bDownOver = true; L;+e)I]  
//nPos = fileAccessI.write (b,0,nRead); %kgT=<E'  
} %e|UA-(  
catch(Exception e){e.printStackTrace ();} m#RMd,'X  
} +OtD@lD`!  
} ((^vsKT  
`Ao"fRv#  
+$/NTUOP  
//打印回应的头信息 ;4Xx5*E  
public void logResponseHead(HttpURLConnection con) ?MFXZ/3(ba  
{ Q7/Jyx|  
for(int i=1;;i++) bBGg4{  
{ lEb H4 g  
String header=con.getHeaderFieldKey(i); $~?)E;S  
if(header!=null) ^v:XON<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); T| R!Aw
.  
Utility.log(header+" : "+con.getHeaderField(header)); rL?{+S]&^)  
else n0%S: (  
break; 3x z z* <  
} `1y@c"t  
} |It{L0=U  
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public void splitterStop() '
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{ N4{g[[ T  
bStop = true; A.r.tf}:  
} m2ph8KC  
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} ]5M
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/* ft iAty0n  
**FileAccess.java ]I;owk,  
*//文件访问(定位，写) o_[
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package NetFox; yBv4 xKMH  
import java.io.*; NL!xkcXO  
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public class FileAccessI implements Serializable{ l}#d^S/  
%%h.`p1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 m93{K7O2e  
RandomAccessFile oSavedFile; )5o6*(Y  
long nPos; uOZS
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public FileAccessI() throws IOException %Rk0sfLvn  
{ aghlYcPg  
this("",0); y'JJ#7O=  
} zhyf}Ta'  

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public FileAccessI(String sName,long nPos) throws IOException :&E~~EUW  
{ A$;*O)  
oSavedFile = new RandomAccessFile(sName,"rw"); %0f*OC  
this.nPos = nPos; i"E_nN"V  
oSavedFile.seek(nPos); 
 {~w!  
} xZloEfv.B  
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S>"
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public synchronized int write(byte[] b,int nStart,int nLen) @]EdUzzKq  
{ @ W q8AFo  
int n = -1; yC!>7@m  
try{ D?H|O[  
oSavedFile.write(b,nStart,nLen); Us>
 
n = nLen; +|4olK$[  
} 4
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catch(IOException e) EvA8<o  
{ " ;\EU4R  
e.printStackTrace (); +hH7|:JQ  
} &@PAv5iNf  
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return n; =H}}dC<)  
} YC*`n3D|'  
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} y35e3  
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/* Lr`Gyl62  
**SiteInfoBean.java wvr`~e  
*/ |I.5]r-EK  
package NetFox; GB6(WAmr  
+>%AG&Pc  
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public class SiteInfoBean { ;b_<5S  
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private String sSiteURL; //Site's URL a3He-76  
private String sFilePath; //Saved File's Path %r:4'$E7|  
private String sFileName; //Saved File's Name KkR.p,/  
private int nSplitter; //Count of Splited Downloading File I7<UC{Ny  
;N _%O  
9HlM0qE5b  
public SiteInfoBean() M IUB]  
{//nSplitter的缺省值为5 ;;EFiaA  
//default value of nSplitter is 5 B{V(g"dM  
this("","","",5); %XXjQ5p  
} v6T<K)S  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  Y@b|/+  
{ `0R>r7f)H  
sSiteURL= sURL; b1Ba}  
sFilePath = sPath; f>?b2a2HX  
sFileName = sName; Jd33QL}Hj  
this.nSplitter = nSpiltter; of`WP  
tZr_{F@  
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} \Fu(IuD  
JS&;7Z$KX  
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public String getSSiteURL() VB4
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{ t & 5s.  
return sSiteURL; h>/L4j*Z  
} N,ZmGzNP)  
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public void setSSiteURL(String value) u>2opI
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{ yJ8_<A  
sSiteURL = value; 9
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} 2o0WS~}5  
SFqq(K2u  
9['>$ON  
public String getSFilePath() 1Msc:7:L  
{ 2j[;M-3  
return sFilePath; 2(Nf$?U@0  
}
;^8X(R  
,B,0o*qc{K  
<!?ZH"F0  
public void setSFilePath(String value)  t&
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{ 1kh()IrA  
sFilePath = value; ^pocbmg  
} (abtCuZ8z  
?"p.Gy)  
8oJp_sw  
public String getSFileName() biHZyUJ  
{ BM02k\%  
return sFileName; :)k|O
nz  
} 3+I"Dm,  
,WS{O6O7  
e~$aJO@B.R  
public void setSFileName(String value) ban;HGGNG{  
{ R!:F
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sFileName = value; v&"sTcS|  
} tSunO-\y  
V:1_k"zQ  
:U'Oc3l#Y  
public int getNSplitter() -L2%,.E>4  
{ zY&/lWW._  
return nSplitter; OUm,;WNLf  
} F'njtrO3  
sfCU"O2G  
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public void setNSplitter(int nCount) I$I',x5Z  
{ [}"m4+  
nSplitter = nCount; XJ?zP=UK  
} =o4McV}  
} hDTM\>.c;s  
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nD{{/_"'  
/* ]Q{MF- EKj  
**Utility.java XC[bEp$  
*/ F2$?[1^f  
package NetFox; y~rtYI  
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public class Utility { -qDL':  
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public Utility() Fr,b5 M<L7  
{ Ng
\]  
S6c>D&Q  
U5H5QW+  
} b|g=&T:pp  
+J:wAmY4  
//线程睡眠 z;EDyd,O>  
public static void sleep(int nSecond) 5f_1 dn  
{ ??g = `yH  
try{ ]goPjfWvU"  
Thread.sleep(nSecond); /Au7X'}  
} 3>k?-%"  
catch(Exception e) /m+.5Qz9)@  
{ WL1$LLzN  
e.printStackTrace (); V(6Ql j7  
} {o8K&XU#&t  
} !]!J"!xg*  
Qy|6A@  
//日志 bN.U2%~!  
public static void log(String sMsg) Uy{ZK*c8i  
{ (l:LG"sy\  
System.err.println(sMsg); ~|=G3(I[  
} w)%/Me3o  
F ss@/-  
5`1p ?  
public static void log(int sMsg) wWB^m@:4  
{ Xe<kd
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System.err.println(sMsg); #e$vv!&}  
} *uvE`4V^Jg  
} ]0myoWpi3  
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@s~*>k#"#  
/* v^1n.l %E  
**TestMethod.java 4XArpKA  
*/ _t\)W(E&  
package NetFox; 8fQaMn4V  
p(S {k]ZL@  
ci{WyIh  
public class TestMethod { xU$15|ny  
'=>l& ;  
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public TestMethod() JS0957K  
{ ///xx/weblogic60b2_win.exe .Wvg{ S-  
try{ !v]~ut !p  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -^= JKd&p  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $3{I'r]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,IQ%7*f;O_  
fileFetch.start(); txemu*  
} +cx(Q(HD\  
catch(Exception e){e.printStackTrace ();} AR5)Uws  
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(Ei} :6,}  
} MD=!
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cW\Y1=Gv|  
&%`0&y  
public static void main(String[] args) m7m)BX%O  
{ SI/p8 ^  
new TestMethod(); T+)#Du  
} 9l:vVp7Uk  
} TDHS/"MbA7  
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