http断点续传简单实现（java)

/* *nV*WUS3  
**SiteFileFetch.java |j!U/n.%w  
*/ $6*6%T5}  
package NetFox; x^6b$>1  
import java.io.*; ,h* 'Cs04h  
import java.net.*; 70T{tB  
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public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean 80Z'1'u0  
long[] nStartPos; //开始位置 rLI);!^-  
long[] nEndPos; //结束位置 pXoT@[}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n_P2l<F~/x  
long nFileLength; //文件长度 Jm]P,jaLc  
boolean bFirst = true; //是否第一次取文件 h0zv@,u  
boolean bStop = false; //停止标志 &&`-A6`p  
File tmpFile; //文件下载的临时信息 Qjd<%!]+\  
DataOutputStream output; //输出到文件的输出流 /fC8jdp&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） v|;}}ol  
public SiteFileFetch(SiteInfoBean bean) throws IOException fH?s~X]  
{  [?moS!  
siteInfoBean = bean; fwz-)?   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2D'$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3 UG UZ  
if(tmpFile.exists ()) ,];QzENw  
{ W
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bFirst = false; 5HW'nhE  
read_nPos(); <g{d>j  
} ;hJz'&UWQ  
else asKAHVT(  
{ n
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nStartPos = new long[bean.getNSplitter()]; )|E617g  
nEndPos = new long[bean.getNSplitter()]; 05Y4=7,!  
} &4jc3_UKV  
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} iJ!p9E*(  
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public void run() {9<c*0l  
{ +L|-W9"@3  
//获得文件长度 \jHIjFwQ  
//分割文件 w ;xbQZ|+  
//实例FileSplitterFetch bTW# f$q:4  
//启动FileSplitterFetch线程 RKO} W#?  
//等待子线程返回 XywsjeI4  
try{ e&ci\x%  
if(bFirst) ^#)]ICV  
{ I
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nFileLength = getFileSize(); whh#J (  
if(nFileLength == -1) @Avve8S  
{ &a?k1R>  
System.err.println("File Length is not known!"); I9O%/^5^[w  
} T1g3`7C3  
else if(nFileLength == -2) )5/,B-+O"  
{ $Lt'xW`8  
System.err.println("File is not access!"); p{oc}dWin  
} $`6Q\=*R/  
else P|QM0GI  
{ 4~Jg\@  
for(int i=0;i<nStartPos.length;i++) J @^Ypq  
{ tu5T^"BqO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0^>b=a  
} 4-JyK%m,0  
for(int i=0;i<nEndPos.length-1;i++) W9/HM!  
{ S$ Z?T  
nEndPos = nStartPos[i+1]; S)=3%toS>  
} (u-eL#@  
nEndPos[nEndPos.length-1] = nFileLength; ]lZg }7h  
} n+SHkrW  
} 5  =Op%  
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//启动子线程 >h{)7Hv  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b;IzK'  
for(int i=0;i<nStartPos.length;i++) J)._&O$  
{ JXF0}T)C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !YENJJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %ZM"c  
nStartPos,nEndPos,i); x|GkXD3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nUf0TkA  
fileSplitterFetch.start(); >Q[3t79^  
} G?<uw RV  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,j e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r&ux|o+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <KBS ;t="1  
nEndPos = " + nFileLength); a9g~(#?a  
// fileSplitterFetch[nPos.length-1].start(); (qDPGd*1  
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hkl9EVO)  
//等待子线程结束 HJjx!7h  
//int count = 0; =;~*YD(%/  
//是否结束while循环 AS/z1M_U  
boolean breakWhile = false; g<g$c<sm  
!v<`^`x9I  

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while(!bStop) N<^)tR8+  
{ {iYrC m[_  
write_nPos(); ErxvGB
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Utility.sleep(500); mKuY=#RP  
breakWhile = true; <ZjT4><  
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for(int i=0;i<nStartPos.length;i++) -1}&\=8M  
{ +,T z +!  
if(!fileSplitterFetch.bDownOver) \HQw$E/p  
{ QzVoU |  
breakWhile = false; YT'olk  
break; U<I
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} U88gJ[$  
} 3@wio[  
if(breakWhile) ]\ t20R{z  
break; *=X61`0  
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//count++; pMd!Jl#(N  
//if(count>4) X"g`hT"i  
// siteStop();
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} 2hsRYh  
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System.err.println("文件下载结束！"); jx14/E+^  
} qi$nG_<<Z  
catch(Exception e){e.printStackTrace ();} $ D.*r*c6  
} u4|)A4n  
^j7>Ul,  
aRy" _dZ2  
//获得文件长度 |J$Bj?  
public long getFileSize() Egmp8:nZl@  
{ ^J'O8G$  
int nFileLength = -1; ){*9$486  
try{ }U|0F#0$  
URL url = new URL(siteInfoBean.getSSiteURL()); T'!p{Fbg;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :QIf0*.O  
httpConnection.setRequestProperty("User-Agent","NetFox"); zE+^WeH|  
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int responseCode=httpConnection.getResponseCode(); #=N6[:,  
if(responseCode>=400) -f["1-A  
{ )zkr[;j~`  
processErrorCode(responseCode); S/dj])g  
return -2; //-2 represent access is error z&y
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} Mh]4K"cs  
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String sHeader; M)3'\x:  
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for(int i=1;;i++) NZz^*Ela  
{ <Vl`EfA(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >dXB)yl  
//Utility.log(in.readLine()); T%4yPmY  
sHeader=httpConnection.getHeaderFieldKey(i); UJ><B"  
if(sHeader!=null) o:`^1  
{ %E[ $np>  
if(sHeader.equals("Content-Length")) 3hcWR'|  
{ SB,#y>Zv?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f`YHZ O  
break; 49= K]
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} kn+@)3W:*  
} Cz6bD$5  
else +/ ?oyC+Z  
break; (-xVW#39  
} }=A+W2D  
} eOahr
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catch(IOException e){e.printStackTrace ();} rJ(AO'=  
catch(Exception e){e.printStackTrace ();} Vi#[kn'
 
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Utility.log(nFileLength); [9yd29pQ]  
; W$.>*O  
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return nFileLength; ;H9 W:_ahE  
} R)-~5"}~  
@(IA:6GN  
4lI&y<F  
//保存下载信息（文件指针位置） n.Y45(@E  
private void write_nPos() `
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{ -$I$zo  
try{ &FG0v<f5Pv  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9Y?``QBN  
output.writeInt(nStartPos.length); k ~4o`eA  
for(int i=0;i<nStartPos.length;i++) E {UhM q7  
{ rpc;*t+z  
// output.writeLong(nPos); F^&@[k7WW  
output.writeLong(fileSplitterFetch.nStartPos); DABV}@K"  
output.writeLong(fileSplitterFetch.nEndPos); uK0L>
  
} 9{0%M  
output.close(); c3WF!~1r  
} zXk^ugFy  
catch(IOException e){e.printStackTrace ();} |@VhR(^O$  
catch(Exception e){e.printStackTrace ();} $."Fz x  
} /#j)GlNp:  
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//读取保存的下载信息（文件指针位置） %qEp{i
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private void read_nPos() r{f
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{ 1Se2@WR'  
try{ Gp=V%w\FDW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fi%lN_Ev?  
int nCount = input.readInt(); tMXNi
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nStartPos = new long[nCount]; ?;A\>sP  
nEndPos = new long[nCount]; GK1P7Qy?V  
for(int i=0;i<nStartPos.length;i++) }{mS"  
{ %v
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nStartPos = input.readLong(); $ago  
nEndPos = input.readLong(); 7Rd(,eWE@  
} qDgy7kkQ  
input.close(); \eAV: qV  
} J!">L+Zcx  
catch(IOException e){e.printStackTrace ();} k>~D  
catch(Exception e){e.printStackTrace ();} $01~G?:]`  
} wbI1~/  
/#SH`ZK  
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private void processErrorCode(int nErrorCode) 9A87vs4[  
{ aGAr24]y  
System.err.println("Error Code : " + nErrorCode); r.c:QY$  
} /N,\st  
,eSpt#M  
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//停止文件下载 5mZwg(si  
public void siteStop() g?*D)WU  
{ TP/bX&bjCy  
bStop = true; {XV'C@B  
for(int i=0;i<nStartPos.length;i++) &qM8)2Y  
fileSplitterFetch.splitterStop(); (M{>9rk8  
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} [;UI8Stw  
} GNSh`Tm=#  
//负责部分文件的抓取 2`A[<S  
**FileSplitterFetch.java 5W=Jn?y2  
*/ m -0EcA/  
package NetFox; 70EH~  
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import java.io.*; %*RZxR):  
import java.net.*; h92KU  
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public class FileSplitterFetch extends Thread { cucT|y  
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String sURL; //File URL 74&{GCL  
long nStartPos; //File Snippet Start Position -9Ygn_M  
long nEndPos; //File Snippet End Position aj=-^iGG  
int nThreadID; //Thread's ID /1uGsE+[  
boolean bDownOver = false; //Downing is over h iK}&  
boolean bStop = false; //Stop identical ;=1[D  
FileAccessI fileAccessI = null; //File Access interface LBmXy8'T`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &|' NDcp  
{ yo%Nz"  
this.sURL = sURL; : %uaaFl  
this.nStartPos = nStart; d[nz0LI|mk  
this.nEndPos = nEnd; nB]mj_)R^  
nThreadID = id; 1&vR7z]*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Wtp=1  
} #%L_wJB-  
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public void run() w,_LC)9  
{ I3}]MAE  
while(nStartPos < nEndPos && !bStop) B\qy:nr j  
{ =kCiJ8q|  
m\E=I5*/  
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try{ ooP{Q r  
URL url = new URL(sURL); y=jZ8+M   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RD;A  
httpConnection.setRequestProperty("User-Agent","NetFox"); UMT}2d%  
String sProperty = "bytes="+nStartPos+"-"; B\l0kiNT  
httpConnection.setRequestProperty("RANGE",sProperty); q(4Ny<=,'K  
Utility.log(sProperty); .u`A4;;Gw  
] mK{E~Zll  
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InputStream input = httpConnection.getInputStream(); hZ.](rD  
//logResponseHead(httpConnection); #r1y|)m`  
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byte[] b = new byte[1024]; Zq H-]?)  
int nRead; t:v>W8N53  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2izBB,# "  
{ 4ElS_u^cP7  
nStartPos += fileAccessI.write(b,0,nRead); DZA '0-  
//if(nThreadID == 1) 'pO-h,{TS  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &JD^\+7U:  
} Qz_4Ms<o  
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Utility.log("Thread " + nThreadID + " is over!"); ZwiXeD+4  
bDownOver = true; Dtyw]|L\H  
//nPos = fileAccessI.write (b,0,nRead); 8i<]$
 
} `B,R+==G:  
catch(Exception e){e.printStackTrace ();} sGpAaGY>  
} fzAkUv
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} t2|0no  
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x?od_M;*8;  
//打印回应的头信息 wF59g38[z$  
public void logResponseHead(HttpURLConnection con) " RIt  
{ !lA~;F  
for(int i=1;;i++) ~PU}==*q  
{ kV8q
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String header=con.getHeaderFieldKey(i); J aJ/|N  
if(header!=null) e AaS }g 0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +}:2DXy@  
Utility.log(header+" : "+con.getHeaderField(header)); I|;C}lfp  
else %:Y(x$Qy  
break; %*Vr}@BA)  
} VW;E14  
}  ?sR(  
"9N;&^I  
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public void splitterStop() L"0?g(< 5  
{ fN:FD`  
bStop = true; S@y?E}  
} {A5$8)nl|  
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} 77wod}h!:  
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/* Vi
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**FileAccess.java QjYw^[o  
*//文件访问(定位，写) %;<g!Vw.k  
package NetFox; L|;sB=$'{  
import java.io.*; ZF8`=D`:R  
Uv~|Xj4.  
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public class FileAccessI implements Serializable{ +rhBC V  
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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 AsvH@
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RandomAccessFile oSavedFile; AVfF<E/  
long nPos; LvZ',u}  
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public FileAccessI() throws IOException :h!'\9  
{ =)*ZrD  
this("",0); Vl>KeZ+  
} ~dP\0x0AB  
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public FileAccessI(String sName,long nPos) throws IOException ]v?jfy  
{ AS[j)x!  
oSavedFile = new RandomAccessFile(sName,"rw"); CC3M7|eO3  
this.nPos = nPos; \+0l#t$  
oSavedFile.seek(nPos); I[w5V;>*  
} 8!@}\6qM  
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wm9wnAy  
public synchronized int write(byte[] b,int nStart,int nLen) 7W5Cm\  
{ }z|9F(I  
int n = -1; sYvlf0  
try{ IS;[oJef  
oSavedFile.write(b,nStart,nLen); ,mC=MpfzJ  
n = nLen; 4I|pkdF_  
} V'UFc>{o  
catch(IOException e) PtzT><  
{ F" 4;nU  
e.printStackTrace (); WT3g31  
} X\i;j!;d  
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return n; VUz+_)  
} FN (O  
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} zE?dQD^OD  
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/* obPG]*3  
**SiteInfoBean.java }7P[%(T5  
*/ p{``a=  
package NetFox; GCv1x->  
bD|VT  
f/4DFs{  
public class SiteInfoBean { |`V=hqe{  
 !$!%era`  
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private String sSiteURL; //Site's URL dO,;k+  
private String sFilePath; //Saved File's Path gr{*wYL  
private String sFileName; //Saved File's Name <HIM k  
private int nSplitter; //Count of Splited Downloading File uY/CiTWr  
h^''ue"  
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public SiteInfoBean() e#k)F.TZ:%  
{//nSplitter的缺省值为5 >l=^3B,j  
//default value of nSplitter is 5
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this("","","",5); _{eA8J(A<  
} G-;EB  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~ tN/  
{ BglbQ'6p  
sSiteURL= sURL; {y%@1q%"  
sFilePath = sPath; 5@I/+D  
sFileName = sName; |L:X$oM  
this.nSplitter = nSpiltter; .WuSW[g  
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/
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} K\s<<dRa  
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public String getSSiteURL() BqA_CW  
{ |oe  
return sSiteURL; <E^;RG  
} 4Mt
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public void setSSiteURL(String value) ZA@zs,o%  
{ lLglF4  
sSiteURL = value; m@0> =s~.  
} raU_Z[  
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public String getSFilePath() =Mxu,A  
{ /g!Xe]Ss  
return sFilePath; :m/qR74+"  
} eIN0T;1T  
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public void setSFilePath(String value) pr,1pqiAf  
{ AI9922}*  
sFilePath = value; kXlI*h  
} Cn5;h(r  
`gJ$fTi&  
bUSa#pNO>  
public String getSFileName() W{j(=<|<  
{ K*4ib/'E a  
return sFileName; Q:b0!  
} *Ue#Sade  
2:e7'}\D.  
0W+RVp=TL1  
public void setSFileName(String value) Bqb`WX[<`  
{ 'R42N3|F  
sFileName = value; zvdIwV&oT  
} "s(|pQh;  
:1@jl2,  
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public int getNSplitter() N3oa!PE  
{ av:%wJUl,$  
return nSplitter; hFhC&2HN  
} [kqO6U  
hPCSAo!|  
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public void setNSplitter(int nCount) 8+32hg@^F  
{ we@*;k@_  
nSplitter = nCount; y6MkaHW[m  
} B+pLW/4l  
} 'UZ i>Ta  
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B[+b%a3  
/* u^WZsW  
**Utility.java _x,(576~  
*/ /ZH*
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package NetFox; NJOV!\k  

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public class Utility { JRAU|gr  
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public Utility() 9F~5Ht  
{ dP]Z:  
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} WHfl|e  
-_]Ceq/  
//线程睡眠 SbsdunW+?  
public static void sleep(int nSecond) Rd5pLrr[0)  
{ Fx)><+-  
try{ VD =f 'D  
Thread.sleep(nSecond); P\z1fscnK  
} =
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catch(Exception e) {BJH}vV1)  
{ #Pg?T%('`  
e.printStackTrace (); |It{L0=U  
} !d[]Qt%mA  
} rhGB l`(B  
HW"5MZ8E  
//日志 s:z  
public static void log(String sMsg) _)4zm  
{ C]ax}P>BQ  
System.err.println(sMsg); M*~XpT3  
} #]^M/y h  
f
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public static void log(int sMsg) u9]M3>  
{ %+UTs'I  
System.err.println(sMsg); I7t}$S6  
} Lw?>1rTT/  
} V|{~9^  
  &._Mh  
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/* 0TiDQ4}i[  
**TestMethod.java z:)*Aobwv  
*/ 4FKgp|Y0  
package NetFox; {?X +Yw  
 ;CV'
 
Z 8GIZ  
public class TestMethod { w[EEA_\  
^?0?*  
%(s2{$3  
public TestMethod() ma"M?aM  
{ ///xx/weblogic60b2_win.exe q>6,g>I  
try{ dKw[#(m5v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %uo#<Ny/ I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c^5fhmlt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); twaH20  
fileFetch.start(); 2&AX_#P  
} Q2Uk0:M  
catch(Exception e){e.printStackTrace ();} <YCR^?hJSi  
i=fhK~Jd  
.PuxF  
} eq9qE^[Z&  
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Kf$6D 79#  
public static void main(String[] args) -:b<~S[  
{ 2t=&h|6EW  
new TestMethod(); ?4Rq +  
} LVL#qNIu  
} : >$v@d  
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