http断点续传简单实现（java)

/* P_{jZ}y(  
**SiteFileFetch.java oI2YJ2?Je8  
*/ _${//`ia=  
package NetFox; _5%NG 3c  
import java.io.*; C % d  
import java.net.*; G{C27k>wa  
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public class SiteFileFetch extends Thread { d@u)'AY%/  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^qgOgu  
long[] nStartPos; //开始位置 3\~ RWoB0u  
long[] nEndPos; //结束位置 Aqp$JM >  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 aOWfu^&H:  
long nFileLength; //文件长度 N=hhuKt]  
boolean bFirst = true; //是否第一次取文件 H/Wo~$  
boolean bStop = false; //停止标志 %8N=4vTJ  
File tmpFile; //文件下载的临时信息 =^L?Sgg  
DataOutputStream output; //输出到文件的输出流 D6MktE)'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ]EhU8bZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException `_*NFv1_  
{ H|]~(.w 1}  
siteInfoBean = bean; "h>B`S  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); luYa+E0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); IW1+^F9NEw  
if(tmpFile.exists ()) |` +G7?)Y  
{ 4PVkKP'/   
bFirst = false; ecjjCt2S  
read_nPos(); 5qx,b&^w  
} 8T2iqqG/1  
else :^Ouv1!e1  
{ EP;TfWc}1  
nStartPos = new long[bean.getNSplitter()]; X=Th  
nEndPos = new long[bean.getNSplitter()]; k'hJ@6eKS  
} R"0fZENTG  
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} SW^/\cJ^  
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public void run() !x, ;&  
{ Z6Owxqfht  
//获得文件长度 0VOj,)K=  
//分割文件 13X0LN  
//实例FileSplitterFetch Wg3\hv29  
//启动FileSplitterFetch线程 e{8j(` (;#  
//等待子线程返回 ~qk5Mk4$  
try{ 0d%p<c  
if(bFirst) ^3qo%=i  
{ Ai 9UB=[R  
nFileLength = getFileSize(); XehpW}2\  
if(nFileLength == -1) m^O9G?  
{ AhjUFz  
System.err.println("File Length is not known!"); ylEQeN  
} 2L'vB1`  
else if(nFileLength == -2) _B5t)7I  
{ !E0zj9 [ R  
System.err.println("File is not access!"); Xg](V.B6  
} :-I~-Yj  
else )AX0x1I|E  
{ J:{$\m'  
for(int i=0;i<nStartPos.length;i++) TvEN0RV2  
{ *TjolE~o  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); e2SU)Tr%b  
} o9l =Q  
for(int i=0;i<nEndPos.length-1;i++) m}x&]">9  
{ YEEgDw]BQ  
nEndPos = nStartPos[i+1]; ae)0Yu`*G7  
} 0NN{2"M$p  
nEndPos[nEndPos.length-1] = nFileLength; tPT\uD#t  
} >UP{=`  
} *mc]Oa  
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//启动子线程 QFI8|i@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Pgy&/-u  
for(int i=0;i<nStartPos.length;i++) )-_NtMr~`!  
{ PgKA>50a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b9ON[qOMN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x4PH-f-7  
nStartPos,nEndPos,i); ,1\nd{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e7{n=M  
fileSplitterFetch.start(); Q]';1#J\  
} {[~ !6&2(k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Wdt9k.hzN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?UX
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Xwg|fr+p  
nEndPos = " + nFileLength); 1PMBo=SUe8  
// fileSplitterFetch[nPos.length-1].start(); ~ caKzq  
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//等待子线程结束 VrF(0,-Z`3  
//int count = 0; ?|8QL9Q"|  
//是否结束while循环 x?J- {6k  
boolean breakWhile = false; `?Pk~7  
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while(!bStop) q16RPqfT  
{ wVvk{tS  
write_nPos(); G2Eke;  
Utility.sleep(500); ec/1Z8}p  
breakWhile = true; fOEw]B#@  
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for(int i=0;i<nStartPos.length;i++) tW;1  
{ h.@
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if(!fileSplitterFetch.bDownOver) RnV )*  
{ )IQa]A  
breakWhile = false; p`lv$ @q'  
break; m.ev~Vv~  
} _]btsv\)f  
} sJ[I<
 
if(breakWhile) e?FjN 9  
break; a"gZw9m@  
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//count++; C&Rv$<qc  
//if(count>4) OKs1irt5  
// siteStop(); y/57 >.3  
} NuZiLtC  
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System.err.println("文件下载结束！"); 'jAX&7G`  
} )Y.H*ca  
catch(Exception e){e.printStackTrace ();} BEWDTOY[  
} KwO;ICdJ  
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//获得文件长度 o9I=zAGjy  
public long getFileSize() _p0@1 s(U  
{ y&;ytNG&<  
int nFileLength = -1; 6 axe  
try{ ZBYFQTEE  
URL url = new URL(siteInfoBean.getSSiteURL()); `5da  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _Q XC5i  
httpConnection.setRequestProperty("User-Agent","NetFox"); F/33# U  
!4Q0   
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int responseCode=httpConnection.getResponseCode(); _{$eOwB  
if(responseCode>=400) 9R$0[HbI3  
{ a}(xZ\n^D;  
processErrorCode(responseCode); 8zhr;Srt  
return -2; //-2 represent access is error O7DaVlln  
} ;W"=s79  
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String sHeader; E~]37!,\\9  
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{,;R\)8D  
for(int i=1;;i++) 4v[Zhf4JM  
{ J  ZH~ {  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o/dj1a~U  
//Utility.log(in.readLine()); C[X2]zr  
sHeader=httpConnection.getHeaderFieldKey(i); Xg<R+o  
if(sHeader!=null) 2g0_[$[m  
{ *
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if(sHeader.equals("Content-Length"))  (zIWJJw  
{ /7[U J'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I='6>+P  
break; |f+`FOliP  
} kg/<<RO  
} .I h'&  
else e-E0Bp  
break; vyS8yJUY  
} .:wo ARW!  
} zEBUR%9  
catch(IOException e){e.printStackTrace ();} ;rj|>  
catch(Exception e){e.printStackTrace ();} eN,6p'&  
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Utility.log(nFileLength); 4QZ|e{t  
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return nFileLength; |~]@hs~  
} puOAt  
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//保存下载信息（文件指针位置） ,v@C=4'm  
private void write_nPos() /:GeXDJw  
{ v$d^>+Y#  
try{ ]8o[&50y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); e8,!x9%J  
output.writeInt(nStartPos.length); YiGSFg  
for(int i=0;i<nStartPos.length;i++) Of gmJ(%  
{ #E;a;$p  
// output.writeLong(nPos); {lO>i&mx  
output.writeLong(fileSplitterFetch.nStartPos); D/oO@;`'c  
output.writeLong(fileSplitterFetch.nEndPos); P9f,zM-  
} crlCN  
output.close(); 0J z|BE3Y  
} L (@".{T  
catch(IOException e){e.printStackTrace ();} HceZTe@  
catch(Exception e){e.printStackTrace ();} i5;_  
} Xaw&41K  
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//读取保存的下载信息（文件指针位置） kP[LS1}*  
private void read_nPos() 2qDyb]9  
{ =u<jxV9  
try{ @g%^H)T  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Sau?Y  
int nCount = input.readInt(); VlFhfOR6
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nStartPos = new long[nCount]; *z
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nEndPos = new long[nCount]; =2OLyZDI  
for(int i=0;i<nStartPos.length;i++) VK[`e[.C  
{ +@BjQ|UZ  
nStartPos = input.readLong(); \F8:6-  
nEndPos = input.readLong(); m ?#WQf  
} #v\o@ArX  
input.close(); XJ6=Hg4_O  
} a_(fqoW  
catch(IOException e){e.printStackTrace ();} /D,<2>o  
catch(Exception e){e.printStackTrace ();} Z_(P^/  
} 9iM[3uyO  
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private void processErrorCode(int nErrorCode) 8c<OX!  
{ Noi+mL  
System.err.println("Error Code : " + nErrorCode); z+{Q(8'b]  
} 'tJ@+(tqw  
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//停止文件下载 bF c %  
public void siteStop() `2a7y]?  
{ LNOz.2fr>  
bStop = true; i/j eb*d0  
for(int i=0;i<nStartPos.length;i++) .q5WK#^  
fileSplitterFetch.splitterStop(); m/p:W/0L  
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} G~{#%i  
} UUR` m  
//负责部分文件的抓取 6I-Qq?L[H  
**FileSplitterFetch.java 2+}hsGnp  
*/
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package NetFox; H{+[ ,l  
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import java.io.*; 66l+cb  
import java.net.*; <4RP:2#  
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public class FileSplitterFetch extends Thread { a=AP*adx8  
cb`ik)=K%  
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String sURL; //File URL p{w:^l(  
long nStartPos; //File Snippet Start Position ,`U'q|b  
long nEndPos; //File Snippet End Position f;]C8/W  
int nThreadID; //Thread's ID 2}kJN8\F  
boolean bDownOver = false; //Downing is over iE* Y@E5x0  
boolean bStop = false; //Stop identical r@ v&~pL  
FileAccessI fileAccessI = null; //File Access interface p.x!dt\1kC  
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w  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /5j]laYK)  
{ .aD=d\  
this.sURL = sURL; ?.6fVSa  
this.nStartPos = nStart; +a74] H"  
this.nEndPos = nEnd; :za:gs0  
nThreadID = id; r9whW;"q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h
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} 3AcCa>
 
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public void run() z~\Y*\f^Y3  
{ 2_CJV  
while(nStartPos < nEndPos && !bStop) 5sguv^;C5  
{ r"=6s/q7  
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try{ 2F|0
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URL url = new URL(sURL); '-vzQd@y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YHfk; FI  
httpConnection.setRequestProperty("User-Agent","NetFox"); TUM7(-,9  
String sProperty = "bytes="+nStartPos+"-"; w/Y6m.i1  
httpConnection.setRequestProperty("RANGE",sProperty); S%2qX"8  
Utility.log(sProperty); |$sMzPCxOk  
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InputStream input = httpConnection.getInputStream(); 0/,Dy2h  
//logResponseHead(httpConnection); Q}kXxud  
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byte[] b = new byte[1024]; SZL('x,"^  
int nRead; kqt.?iJw  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }TsND6Ws3  
{ N^xk.O_TO  
nStartPos += fileAccessI.write(b,0,nRead); +WB';D  
//if(nThreadID == 1) &]P1IQ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v8NoD_  
} 0qhSV B5  
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Utility.log("Thread " + nThreadID + " is over!"); 2sOetmWE7  
bDownOver = true; uH=^ILN.  
//nPos = fileAccessI.write (b,0,nRead); Fv2U@n6'v  
} O[v(kH'  
catch(Exception e){e.printStackTrace ();} x>*#cOVz;C  
} aOK,Mm:iO  
} Hsvu&>[`S  
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//打印回应的头信息 NkL>ru!b9  
public void logResponseHead(HttpURLConnection con) VFjNrngl  
{ C|H/x\?zRv  
for(int i=1;;i++) _{f7e^;  
{ #Ss lH  
String header=con.getHeaderFieldKey(i); {((|IvP`  
if(header!=null) EhK5<v}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /FW{>N1  
Utility.log(header+" : "+con.getHeaderField(header)); z3Ro*yJU  
else &&er7_Q  
break; H;=++Dh  
} >+E   
} \o2cztl=  
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t)h{ w"v  
public void splitterStop() $S_G:}tna  
{ `ot<BwxJ  
bStop = true; />
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} ~n)<L7  
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} V-.Nc#  
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/* 9m:G8j'  
**FileAccess.java u&\QZW?  
*//文件访问(定位，写) UYW{AG2C  
package NetFox; [H&Z /.{F  
import java.io.*; qp)a`'Pq  
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public class FileAccessI implements Serializable{ sUEvL(%nY  
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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 @}B,l.Tj  
RandomAccessFile oSavedFile; @h$4Mt7N  
long nPos; q]r
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public FileAccessI() throws IOException SB}0u=5  
{ (iO8[  
this("",0); !1<?ddH6  
} Wo[*P\8  
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public FileAccessI(String sName,long nPos) throws IOException 7B| #*IZe  
{ F^bzE5#  
oSavedFile = new RandomAccessFile(sName,"rw"); v
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this.nPos = nPos; s1| +LT,D  
oSavedFile.seek(nPos); @%}4R`S0  
} rs?"pGz;  

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public synchronized int write(byte[] b,int nStart,int nLen) @4%
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{ eO?.8OM-a  
int n = -1; Rz_fNlA  
try{ Sy?O(BMo  
oSavedFile.write(b,nStart,nLen); _T)G?iv:&  
n = nLen; tF@hH}{;  
} ?!$uMKyt  
catch(IOException e) 3xU in  
{
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e.printStackTrace (); @=kDaPme92  
} UNB'Xjp}@  
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return n; b9(_bsc  
} 6)B6c. 5o  
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} ?k7z5ow  
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/* =ZaTD-%id  
**SiteInfoBean.java ,( ?q  
*/ `l0&,]  
package NetFox; #ARQ
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\ $PB~-Z  
public class SiteInfoBean { Q{~WWv  
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private String sSiteURL; //Site's URL :s}6a23  
private String sFilePath; //Saved File's Path IJ`%Zh{f  
private String sFileName; //Saved File's Name 0L5n<<7  
private int nSplitter; //Count of Splited Downloading File !&n'1gJ)kd  
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public SiteInfoBean() <Xsy{7  
{//nSplitter的缺省值为5 z!<X{& e  
//default value of nSplitter is 5 ?C[W~m P  
this("","","",5); )Uk!;b  
} 1@}`dc  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) TBGN',,  
{ c8^M::NI  
sSiteURL= sURL; j<HBzqP%6  
sFilePath = sPath; "\x<Zg;  
sFileName = sName; zv^km5by  
this.nSplitter = nSpiltter; d3nMeAI AO  
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} GbLuXU  
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public String getSSiteURL()  WB7pdSZ  
{ V?.')?'V  
return sSiteURL; 907N;r  
} eYN=?  
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public void setSSiteURL(String value) S^Lu RF]F  
{ P0B`H7D  
sSiteURL = value; >;$C
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} .9cQq/{b  
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public String getSFilePath() bp>-{Nv  
{ "}ms|  
return sFilePath; ","O8'$OC  
} fbG+
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public void setSFilePath(String value) $j+RUelFY  
{ 6/%dD 
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sFilePath = value; o4%H/|Oq.  
} 0bR)]"K  
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public String getSFileName() R">-h;#  
{ P1r)n{;  
return sFileName; a7]wPXKq  
} 8NE+G.:G  
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public void setSFileName(String value) t-;zgW5mwF  
{ F
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sFileName = value; yGxAur=dE  
} DR%16y<h  
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public int getNSplitter() k%|Sl>{Ir  
{ >!D^F]CH  
return nSplitter; U '$W$()p  
} **D3.-0u&  
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|[ )e5Xhd  
public void setNSplitter(int nCount) /O^aFIxk  
{ At0ahy+  
nSplitter = nCount; xA&RMu&  
} m\0Xh*  
} +sW;p?K7eO  
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/* Bp7`W:?#"  
**Utility.java C-}@.wr(  
*/ xsO "H8  
package NetFox;
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>, 9R :X(  
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public class Utility { UGb<&)  
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public Utility() N,4. %|1  
{ DH>>u  
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} !1
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\ ";^nk*  
//线程睡眠 '|7'dlW  
public static void sleep(int nSecond) n|M~C\*  
{ QF74'  
try{ okkMx"  
Thread.sleep(nSecond); #3_t}<fX  
} r-s9]0"7~  
catch(Exception e) ceUhCb  
{ ,8`CsY^1  
e.printStackTrace (); 1zP)~p3a  
} "8#EA<lsS  
} GL^84[f-T  
;_oJGII?br  
//日志 5{Oq* |  
public static void log(String sMsg) n([9U0!gu  
{ GpZ}xY'|w,  
System.err.println(sMsg); LZI[5tA"  
} JP1XH k  
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v[+ ]  
public static void log(int sMsg) N87)rhXSo,  
{ EZee kxs  
System.err.println(sMsg); Q
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} 5kx-s6`!  
} Errs6  
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/* RA$%3L[A!  
**TestMethod.java Tv6HPD$[  
*/ !Pc&Sg  
package NetFox; )jPIBzMys  
?_t_rF(?6  
hCPyCq]  
public class TestMethod { EpU}~vC9C  
;@FCaj&  
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public TestMethod() Q.MbzSgXL  
{ ///xx/weblogic60b2_win.exe {%+UQ!]d8  
try{ <]f{X<ef  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HJ+Q7)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ' +f(9/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {WvYb,
  
fileFetch.start(); 8.zYa(<2  
} +.-g`Vyz*  
catch(Exception e){e.printStackTrace ();} d<cqY<y VA  
_A~>?gJ;,  
.G-L/*&%  
} vyvb-oz;u  
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public static void main(String[] args) ]YrgkC35  
{ *|as-!${k  
new TestMethod(); va2FgW`Bd+  
} S1o[)q   
} sV;q(,oru  
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