http断点续传简单实现（java)

/* VK`b'U&l"  
**SiteFileFetch.java ?hDEFW9&^x  
*/ ={feN L  
package NetFox; k5}i^^.  
import java.io.*; dc lJ  
import java.net.*; Bwll [=_I  
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public class SiteFileFetch extends Thread { 4] DmgOru%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \uanQ|Nu  
long[] nStartPos; //开始位置 F7"Ihb^l  
long[] nEndPos; //结束位置 }^LcKV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 WtlIrdc  
long nFileLength; //文件长度 C<n.C*o  
boolean bFirst = true; //是否第一次取文件 c[",WB<9  
boolean bStop = false; //停止标志 )k7`!@ID  
File tmpFile; //文件下载的临时信息 yUH8  
DataOutputStream output; //输出到文件的输出流 KrbNo$0%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） CQtd%'rt6  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9sT?"(=  
{ Wa[~)A  
siteInfoBean = bean; =BGc@:2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,][+:fvS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); GXHk{G@TS  
if(tmpFile.exists ()) &Rn/c}[{  
{ b0KorUr  
bFirst = false; ^k-H$]  
read_nPos(); c\;}ov+  
} C %EQ9Iq6r  
else /6S/a*`<X  
{ n+!.0d}6  
nStartPos = new long[bean.getNSplitter()]; _fa]2I  
nEndPos = new long[bean.getNSplitter()]; CZ&TUE|:DA  
} h+$_:](PC  
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} {s`1+6_&Vz  
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public void run() UT^t7MY#O  
{ 3'.OghI  
//获得文件长度 Dri1A%  
//分割文件 txL5'mK  
//实例FileSplitterFetch <edAWc+  
//启动FileSplitterFetch线程  |u$AzI  
//等待子线程返回 -k<.Q=]<t  
try{ @*2FG\c<  
if(bFirst) c6lEWC:  
{ kbMIMZC/G  
nFileLength = getFileSize(); (bT\HW%m  
if(nFileLength == -1) L>@6lhD)x  
{ 47icy-@kg  
System.err.println("File Length is not known!"); 0kiW629o  
} |Ec$%
 
else if(nFileLength == -2) 3]c<7vdl  
{ D#k>.)g  
System.err.println("File is not access!"); Ws1<Jt3/."  
} }wv$ #H[  
else #lB[]2]N  
{ @u$oqjK  
for(int i=0;i<nStartPos.length;i++) <B`=oO%o  
{ I&(cdKY z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _nTjCN625  
} e=F' O] 5  
for(int i=0;i<nEndPos.length-1;i++) v4ueFEY  
{ liU=5BL  
nEndPos = nStartPos[i+1]; Stp??  
} o#+!H!C.O  
nEndPos[nEndPos.length-1] = nFileLength; iT|+<h  
} -)$)<k  
} 4ErDGYg}  
}
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_6(zG.Fg  
//启动子线程 Jl9T[QAJn1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zJx<]=]  
for(int i=0;i<nStartPos.length;i++) -l,ib=ne  
{ zg5u  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s!+?)bB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `9wz:s QtP  
nStartPos,nEndPos,i); Y{J/Oib  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "1[N;|xa  
fileSplitterFetch.start(); ga,yFw  
} @FbzKHd
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]T*{M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \ _i`=dx  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [S<DdTY9hZ  
nEndPos = " + nFileLength); i;\i4MT  
// fileSplitterFetch[nPos.length-1].start(); Z,d/FC#y(  
->j9(76"  
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//等待子线程结束 lv\2vRYw-  
//int count = 0; !IGVN:E  
//是否结束while循环 4 5Ql7~  
boolean breakWhile = false; {`3;Pd`  
"?N`9J|j)~  
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while(!bStop) Cw+ (,1  
{ Ia(A&Za  
write_nPos(); $h$+EE!  
Utility.sleep(500); Z4(2&t^  
breakWhile = true; nrf%/L  
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for(int i=0;i<nStartPos.length;i++) TIvLY5 HG  
{ 6}|vfw  
if(!fileSplitterFetch.bDownOver) jV7q)\uu^  
{ ^QnVYTM  
breakWhile = false; +0=RC^   
break; *PMql$  
} ++kiCoC  
} ,O-lDzcw  
if(breakWhile) n;q7?KW8  
break; o%|1D'f^  
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//count++; "qDEI}  
//if(count>4) .&[nS<~`  
// siteStop(); L?Lp``%bI7  
} 9YvMJ  
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System.err.println("文件下载结束！"); i\<l&W  
} Y]n^(V  
catch(Exception e){e.printStackTrace ();} G_o/ lIz"  
} p,4z;.s$  
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//获得文件长度 d+IPa<N  
public long getFileSize() l s_i)X  
{ ;wN.RPE_^  
int nFileLength = -1; R]r~TJ o  
try{  c\x?k<=  
URL url = new URL(siteInfoBean.getSSiteURL()); Y

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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I@z{Gr  
httpConnection.setRequestProperty("User-Agent","NetFox"); -~aVt~{k/  
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int responseCode=httpConnection.getResponseCode(); ;N j5NB7  
if(responseCode>=400) 2+^#<Uok  
{ C )PN  
processErrorCode(responseCode); 5(F!*6i>  
return -2; //-2 represent access is error kPxEGuL'  
} z^oi15D|{  
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String sHeader; \(z)]D  
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for(int i=1;;i++) Fj5^_2MU:  
{ 97BL%_^k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'WOWm$2  
//Utility.log(in.readLine()); Ft|a/e  
sHeader=httpConnection.getHeaderFieldKey(i); 1XZ&X]  
if(sHeader!=null) -p)HH@6a  
{ wHY;Y-(ZT  
if(sHeader.equals("Content-Length")) e)iVX<qb  
{ D!-zQ`^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));  <Nw?9P  
break; fkI<RgM  
} Zkz:h7GUG-  
} =]^*-f}J9  
else '}
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break; *&U9npN  
} <W5F~K ;41  
} ]xS< \{og  
catch(IOException e){e.printStackTrace ();} z;3}GxE-si  
catch(Exception e){e.printStackTrace ();} xA-G&oC]<T  
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Utility.log(nFileLength); zJV4)  
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return nFileLength; B]hZ4.B1  
} '6aH*B:}*;  
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//保存下载信息（文件指针位置）
@9L%`=]b^  
private void write_nPos() *$s)p>  
{ eHjR/MMr_  
try{ :l7\7IT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `^6}Dn  
output.writeInt(nStartPos.length); Fq{nc]L6  
for(int i=0;i<nStartPos.length;i++) g\^(>Ouc  
{ PEBQ|k8g&  
// output.writeLong(nPos); w|M?t{  
output.writeLong(fileSplitterFetch.nStartPos); MBg^U<
t8  
output.writeLong(fileSplitterFetch.nEndPos); YnNei 7R  
} xqG` _S l  
output.close(); (V+(\<M  
} w S;(u[W  
catch(IOException e){e.printStackTrace ();} |{_%YM($  
catch(Exception e){e.printStackTrace ();} qD9B[s8  
} PC3wzJ\\S  
#AY+[+  
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//读取保存的下载信息（文件指针位置） -&HN h\  
private void read_nPos() !.F\v.  
{ ~
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try{ GY4yZa  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); e;gf??8}  
int nCount = input.readInt(); P(Lwpa,S  
nStartPos = new long[nCount]; {jv1hKTa  
nEndPos = new long[nCount]; !"1bV [^  
for(int i=0;i<nStartPos.length;i++) CsE|pXVG  
{ HPgMVp'  
nStartPos = input.readLong(); WUxr@0  
nEndPos = input.readLong(); -7yX>Hjl  
} :<jf}[w!  
input.close(); J6Kfz~%  
} D@3|n
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catch(IOException e){e.printStackTrace ();} 1.>`h:  
catch(Exception e){e.printStackTrace ();} 1%+0OmV&  
} Llzowlfe  
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private void processErrorCode(int nErrorCode) mhs%b4'>  
{ T^Z#x-Q  
System.err.println("Error Code : " + nErrorCode); !KF;Z|_(
I  
} |e\:0O?  
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F4PD3E_#  
//停止文件下载 z=u4&x|xA  
public void siteStop() M0]fh5O  
{ %Cr-cR0  
bStop = true; vi=yR  
for(int i=0;i<nStartPos.length;i++) IAtZ-cM<  
fileSplitterFetch.splitterStop(); H;Bj\-Pa  
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} Kp99y  
} 9R E;50h  
//负责部分文件的抓取 WAQv4&xGM  
**FileSplitterFetch.java $)uQ%/DH>  
*/ }^iE|YKz  
package NetFox; B 51LZP  
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import java.io.*; )-sEm`(`I9  
import java.net.*; vdo[qk\C  
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public class FileSplitterFetch extends Thread { /@OGYYH,M  
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String sURL; //File URL h(zi$V  
long nStartPos; //File Snippet Start Position HY42G#^  
long nEndPos; //File Snippet End Position wgufk{:  
int nThreadID; //Thread's ID y_nh~&  
boolean bDownOver = false; //Downing is over 7X.1QSuE  
boolean bStop = false; //Stop identical ar{e<&Bny  
FileAccessI fileAccessI = null; //File Access interface >Te{a*`"m:  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |;].~7^  
{ Lf,gS*Tg?  
this.sURL = sURL; 44]ae~@a  
this.nStartPos = nStart; ^a]i&o[c  
this.nEndPos = nEnd; {wm  `  
nThreadID = id; Z
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 0q3:"X  
} (Hsf
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.!`j3W]  
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public void run() NfSe(rd  
{ NT nn!k  
while(nStartPos < nEndPos && !bStop) ZqhINM*Rm  
{ k82'gJ;MC=  
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try{ '.bMkty#  
URL url = new URL(sURL); F%Xq}LMd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *zx;81X=  
httpConnection.setRequestProperty("User-Agent","NetFox"); v14[G@V~\  
String sProperty = "bytes="+nStartPos+"-"; x_Z~k  
httpConnection.setRequestProperty("RANGE",sProperty); 6ZM<M7(V  
Utility.log(sProperty); @3G3l|~>  
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InputStream input = httpConnection.getInputStream(); U-Iwda8v  
//logResponseHead(httpConnection); J|>P,x#G  
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byte[] b = new byte[1024]; B^OhL!*tI  
int nRead; fGxa~Unx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;CC[>  
{ n b{8zo  
nStartPos += fileAccessI.write(b,0,nRead); yf$7<gwX  
//if(nThreadID == 1) fL@[B{XMM  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4ASc`w*0  
} ND`~|6
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2vur_`cV  
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Utility.log("Thread " + nThreadID + " is over!"); vbWX`skU  
bDownOver = true; ;^xku%u  
//nPos = fileAccessI.write (b,0,nRead); Ufk7%`  
} *s/F4?*  
catch(Exception e){e.printStackTrace ();} d2(n3Xf  
} xo*a9H?@  
} *L!R4;ubE  
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y
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//打印回应的头信息 5=$D~>-#  
public void logResponseHead(HttpURLConnection con) /
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{ t4Z.b 5g  
for(int i=1;;i++) <vAg\Tv:S  
{ 2qEy"DKu  
String header=con.getHeaderFieldKey(i); 4u;W1=+Vn  
if(header!=null) `yf#(YP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &^Xm4r%u_  
Utility.log(header+" : "+con.getHeaderField(header)); `fL$t0"  
else a]Lr<i8#%  
break; sQ_{zOUPh  
} 2#rF/!`^  
} TN0dfba[  
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public void splitterStop() {:? -)Xq  
{ =A,i9Z&  
bStop = true; S |B7HS5  
} >Rr]e`3wG  
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} ^y??pp<1J  
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uh GL1{  
/* kmuF*0Bjk  
**FileAccess.java Mbi)mybM  
*//文件访问(定位，写) OW6i2>Or  
package NetFox; /6f$%:q  
import java.io.*; {!<zk+h$  
7wZKK0;T  
~UL;O\-b0  
public class FileAccessI implements Serializable{ Q!@"Y/  
=XqmFr;h  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ('>!dXA$  
RandomAccessFile oSavedFile; MN#\P1  
long nPos; DSQ2z3s2  
,Z3.Le"  
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public FileAccessI() throws IOException ;8ugI  
{ M,7v}[Tbl  
this("",0); v_b%2;<1  
} OpiN,>;  
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public FileAccessI(String sName,long nPos) throws IOException a*o=,!  
{ UD.$C  
oSavedFile = new RandomAccessFile(sName,"rw"); b2ZKhS8  
this.nPos = nPos; VRT| OUq  
oSavedFile.seek(nPos); [t>}M6?R:  
} 4Sw)IU~K(  
['{mW4i  
0Pbv7)=XL  
public synchronized int write(byte[] b,int nStart,int nLen) 2o6%P}C  
{ LB-4
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int n = -1; yQh":"$k  
try{ VJm).>E3k  
oSavedFile.write(b,nStart,nLen); g#:?Ay-m  
n = nLen; ':J[KWuV  
} V+DN<F-  
catch(IOException e) $
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{ sN;xHTY  
e.printStackTrace (); g }5lGz4  
} T,5]EHe
a  
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P)S
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return n; `vUilh ^c  
} eAPGy-  
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} MsfY|(/m  
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/* Hh,q)(Wo  
**SiteInfoBean.java ]^E<e!z={$  
*/ g&X$)V4C  
package NetFox; YGN
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4OC^IS  
tpU[KR[
-  
public class SiteInfoBean { *i&ks>4N  
bF<FX_}!s!  
8|HuxE  
private String sSiteURL; //Site's URL r. :LZEr  
private String sFilePath; //Saved File's Path +%o
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private String sFileName; //Saved File's Name ]~GwZB'M  
private int nSplitter; //Count of Splited Downloading File )}tI8  
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public SiteInfoBean() ,A4v|]kq]  
{//nSplitter的缺省值为5 '0lX;z1  
//default value of nSplitter is 5 3Oy?_a$  
this("","","",5); ]*D=^kA0[  
} COZ<^*=A#p  
;&oS=6$  
P|l62!m<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3* 1cCM42  
{ j!F5gP-l  
sSiteURL= sURL; [}|x@ v9  
sFilePath = sPath; b:SjJA,HM  
sFileName = sName; nd
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this.nSplitter = nSpiltter; w9G (^jS6  
pxDkf|*  
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} `O5wM\Z  
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public String getSSiteURL() AAb3Jf`UW  
{ fp^{612O?  
return sSiteURL; &gR)Y3  
} eVGO6 2|!  
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public void setSSiteURL(String value) 5bKM}?=L  
{ $SQUN*/>  
sSiteURL = value; 6j/g/!9c!  
} "wy|gnQJ  
MAb*4e#  
x-1RmL_%  
public String getSFilePath() 8iA[w-Pv  
{ }OL?k/w  
return sFilePath; f#f<Ii  
} C-u'Me)H  
L7VDZCV  
$KHw=<:)/  
public void setSFilePath(String value) 7@oM?r7td  
{ >"5f B  
sFilePath = value; W8,4LxH  
} Ve)P/Zz}^  
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*  
;UUpkOQO(  
public String getSFileName() 3Xcjr2]~  
{ 1cq"H/N  
return sFileName; u
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} Gj!9#on$7R  
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public void setSFileName(String value) F#-mseKhc  
{
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sFileName = value; >8M=REn4  
} Bie#GKc  
S#Q0aGj  
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public int getNSplitter() !:Z lVIA  
{ >-oB%T
 
return nSplitter; e<A6=}  
} wr5ScsNS  
A
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X} {z7[  
public void setNSplitter(int nCount) -+ylJo[D  
{ C-h9_<AwJQ  
nSplitter = nCount; ;YN`E  
} ] MP*5U>;  
} b'r</ncZ  
LY:%k|L9  
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/* LuW>8K\  
**Utility.java x%_VzqR`  
*/ = y@*vl   
package NetFox; RG&
t0%yj}  
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!WSY75  
public class Utility { *Ri\7CqU"6  
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I%(YR"  
public Utility() =M6Ph%  
{ (1IYOlG4  
#)r^ZA&E  
QHU|aC{r  
} \<ko)I#%  
p~'iK4[&6  
//线程睡眠 >V%lA3  
public static void sleep(int nSecond) 6;:z?Q  
{ \1Xr4H u  
try{ Yyx
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Thread.sleep(nSecond); Xfc+0$U@  
} Y-?0!a=e.  
catch(Exception e) |E?PQ?P  
{ r=Tz++!  
e.printStackTrace (); #Mw 6>5}<  
} 22OfbwCb  
} q\pI&B  
6b2Z}B  
//日志 |`|#-xu  
public static void log(String sMsg) %?`O .W  
{ Z)&!ZlM  
System.err.println(sMsg); ='vD4}"j  
} Ko|m<;LX  
Y1Q240  
k=W~ot&  
public static void log(int sMsg) )-\C{>  
{ ]-j.\+(*  
System.err.println(sMsg); oBO4a^D  
} 9r.h^  
} PZ>(cvX&  
`5Bv2wlIV  
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/* J Bgq2  
**TestMethod.java 
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*/ tVv/G~(  
package NetFox; ))%f"=:wt  
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public class TestMethod { -
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skm~~JM^  
v,'k2H  
public TestMethod() ;kI)j ?  
{ ///xx/weblogic60b2_win.exe 4Ei8G]O $_  
try{ [g bFs-B2/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1Q_Q-Z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !,+<?o y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `w&?SXFO8  
fileFetch.start(); z:a7)z  
} =2t=Zyp0Y  
catch(Exception e){e.printStackTrace ();} wz..  
o|$r;<o3R  
RNF%i~nhO  
} &S=Qu?H  
2`^6``  
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public static void main(String[] args) 4bCA"QM[[  
{ 4_D *xW  
new TestMethod(); )&DsRA7v  
} 3$?nzKTW\  
} 0bpGPG's&  
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