http断点续传简单实现（java)

/* Owr`ip\  
**SiteFileFetch.java Mu%'cwp$  
*/ TvP# /qGgG  
package NetFox; ^q
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import java.io.*; a"zoDD/  
import java.net.*; ZAP+jX;  
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public class SiteFileFetch extends Thread { 4>W`XH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )v9[/ ]*P  
long[] nStartPos; //开始位置 uu:)jxi  
long[] nEndPos; //结束位置 t&xx-4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @K/Ia!Lw  
long nFileLength; //文件长度 :U9R 1^}A  
boolean bFirst = true; //是否第一次取文件
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boolean bStop = false; //停止标志 A>?fbY2n  
File tmpFile; //文件下载的临时信息 @FTi*$Ix  
DataOutputStream output; //输出到文件的输出流 EDo (  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q@8[ql1l  
public SiteFileFetch(SiteInfoBean bean) throws IOException E;q
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{ 1
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siteInfoBean = bean; qEAF!iB]L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5-OvPTY`M  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); HZ}*o%O  
if(tmpFile.exists ()) I?>#neHc6  
{ <%z/6I Af|  
bFirst = false; B4}XK=)  
read_nPos(); Y[!a82MTzn  
} ]Q3Gj@6  
else cGp^;> ]M  
{ +[ItkfSod!  
nStartPos = new long[bean.getNSplitter()]; wL
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nEndPos = new long[bean.getNSplitter()]; G DV-wPX  
} L9T u
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} #*!$!c{  
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public void run() K>[H@|k\k  
{ 5)UmA8"zVB  
//获得文件长度 CC\z_C*P-p  
//分割文件 `y}
d)"!  
//实例FileSplitterFetch q8Dwu3D  
//启动FileSplitterFetch线程 G)&'8W F5o  
//等待子线程返回 qx)k1QY  
try{ o(P:f)B  
if(bFirst) RY{tX`  
{ =FmU]DV  
nFileLength = getFileSize(); x/=j$oA  
if(nFileLength == -1) j;)6uia*A  
{ uNbA>*c4M  
System.err.println("File Length is not known!"); /<0D E22  
} rHlF& ET  
else if(nFileLength == -2)  IMza 2  
{ GcR`{ 3hO  
System.err.println("File is not access!"); {0 ~0  
} c*dw
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else lQBM0|n  
{ Gq*)]X{Ua  
for(int i=0;i<nStartPos.length;i++) E0Q"qEvU  
{ R(sM(x5a`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0?SLRz8  
} $hSZ@w|IF  
for(int i=0;i<nEndPos.length-1;i++) :,m)D775S  
{ BuTIJb+Q\  
nEndPos = nStartPos[i+1]; opMUt,4  
} KIo}Gd&  
nEndPos[nEndPos.length-1] = nFileLength; ZRB 0OH  
} Yys~p2  
} }&DB5M  
=[JN'|Q+  
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//启动子线程 |a{]P=<q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `fZD%o3l  
for(int i=0;i<nStartPos.length;i++) 2HXKz7da  
{ 9Yyg}l:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zU~..;C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <im<(=m9  
nStartPos,nEndPos,i); vLuQe0l{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /y)"j#-eW  
fileSplitterFetch.start(); |A0$XU{  
} v9U(sEDq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), = O1;vc}AA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %i8>w:@NW  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", IY6_JGe_w  
nEndPos = " + nFileLength); abeSkWUL(  
// fileSplitterFetch[nPos.length-1].start(); DYlvxF`  
T-C#xmY(  
-l H>8+  
//等待子线程结束 | ",[C3Jg  
//int count = 0; OZD!#YI  
//是否结束while循环 Rt^<xXX$  
boolean breakWhile = false; p{q!jm~Nq  
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while(!bStop) W@,p9=425  
{ -Zg @D(pF  
write_nPos(); Reu{   
Utility.sleep(500); b$O_L4CP  
breakWhile = true; 9
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for(int i=0;i<nStartPos.length;i++) =nx:GT3&[  
{ H'{?aaK|t  
if(!fileSplitterFetch.bDownOver) [!@oRK
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{ `QdQ?9x{F  
breakWhile = false; *xg`Kwl5Kl  
break; +RV-VrV  
} S tnv>  
} UVc<C 1q  
if(breakWhile) JhCkkw  
break; N4mJU'_{  
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+'/}[1q1/T  
//count++; (\t_Hs::a  
//if(count>4) ZuvPDW%  
// siteStop(); V.ji _vX  
} Hpi%9SAM  
oD#>8Aws  
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System.err.println("文件下载结束！"); vA"niO  
} \c~{o+UD-  
catch(Exception e){e.printStackTrace ();} knOnUU  
} rN1U.FRe/
 

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//获得文件长度 B>Cs&}Y!  
public long getFileSize() xs'kO=  
{ $tCcjBK\  
int nFileLength = -1; {^2W>^  
try{ #)0Tt>d6  
URL url = new URL(siteInfoBean.getSSiteURL()); y168K[p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :X1cA
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httpConnection.setRequestProperty("User-Agent","NetFox"); t{SMSp  
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int responseCode=httpConnection.getResponseCode(); xN3 [Kp  
if(responseCode>=400) 8b:clvh  
{ 
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processErrorCode(responseCode); bugFl>  
return -2; //-2 represent access is error L; q)8Pb  
} :%#r.p"6x  
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String sHeader; oWDSK^  

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for(int i=1;;i++) m0j|58~  
{ DVl[t8K!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); W&e'3gk_  
//Utility.log(in.readLine()); "65||[=
8  
sHeader=httpConnection.getHeaderFieldKey(i); *:9 >W$0u  
if(sHeader!=null) H5Ux.]y  
{ Ty3CBR{6  
if(sHeader.equals("Content-Length")) SgpZ;\_  
{ .6#cDrK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U.RW4df%E  
break; VJN/#   
} O:;OR'N9  
} -4e)N*VVu  
else g={]Mzh  
break; N&fW9s}  
} *O+R|Cdp/  
} f4'El2>-86  
catch(IOException e){e.printStackTrace ();} v`S2M  
catch(Exception e){e.printStackTrace ();} T+;H#&  
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Utility.log(nFileLength); 3J'73)y  
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return nFileLength; dUoWo3r=  
} E+}GxFG-:  
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//保存下载信息（文件指针位置） d&[iEU  
private void write_nPos() AozmO  
{ @sw9A93A  
try{ \fK47oV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |P~O15V*Q  
output.writeInt(nStartPos.length); K`Bq(z?/  
for(int i=0;i<nStartPos.length;i++) nTys4R  
{ (;0$i?3\  
// output.writeLong(nPos); .4Qb5I2#  
output.writeLong(fileSplitterFetch.nStartPos); )o#6-K+b  
output.writeLong(fileSplitterFetch.nEndPos); /a[V!<"R  
} y]}b?R~p=  
output.close(); AqV09 $  
} sULIrYRA  
catch(IOException e){e.printStackTrace ();} ;OOj[
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catch(Exception e){e.printStackTrace ();} +`;+RDKY*  
} `FA)om  
>vWEUE[  
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//读取保存的下载信息（文件指针位置） i`[#W(m  
private void read_nPos() 5vD3K!\u  
{ v:rD3=M-  
try{ 6exI_3A4jh  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <nDNiM#  
int nCount = input.readInt(); +I|Rk&  
nStartPos = new long[nCount]; U^%9 )4bj  
nEndPos = new long[nCount]; rO/a,vV  
for(int i=0;i<nStartPos.length;i++) "^;#f+0  
{ HLjvKE=W  
nStartPos = input.readLong(); $!!R:Wn/R  
nEndPos = input.readLong(); iv:,fkwG  
} {(rf/:X!p  
input.close(); X*pZNz&E  
} T/[f5?p  
catch(IOException e){e.printStackTrace ();} h&lyxYZ+T$  
catch(Exception e){e.printStackTrace ();} `6&`wKz  
} ~Fy`>*  
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private void processErrorCode(int nErrorCode) vqq6B/r@Fu  
{ Y[W6Sc  
System.err.println("Error Code : " + nErrorCode); >s&XX, w  
} >n]oB~P%  
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//停止文件下载 @-0Fe9 n=  
public void siteStop() 9khjwt  
{ N99[.mErU  
bStop = true; ^_@r.y]  
for(int i=0;i<nStartPos.length;i++) :<L5sp  
fileSplitterFetch.splitterStop(); /@VsqD  
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} R"@7m!IA  
} v@VLVf)>9^  
//负责部分文件的抓取 E W`W~h[  
**FileSplitterFetch.java jD
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*/ F8;mYuA  
package NetFox; 6DB0ni  
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import java.io.*; C1b*v&1{
 
import java.net.*; _ w/_(k  
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public class FileSplitterFetch extends Thread {  Nj+a2[  
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String sURL; //File URL AcKU^T+  
long nStartPos; //File Snippet Start Position iC\%_5/_  
long nEndPos; //File Snippet End Position alFNSRY  
int nThreadID; //Thread's ID u t$c)_  
boolean bDownOver = false; //Downing is over j !`B'{cH  
boolean bStop = false; //Stop identical xA92C  
FileAccessI fileAccessI = null; //File Access interface 'xIyG
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .46#`4av  
{ `xCOR  
this.sURL = sURL; 7'z(~3D  
this.nStartPos = nStart; _Hc%4I  
this.nEndPos = nEnd; ;`DD}j`  
nThreadID = id; Xh?4mKgu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0LdJZP  
} F>*{
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public void run() K*1.'9/  
{ Goxl3LS<  
while(nStartPos < nEndPos && !bStop) HmMO*k<6@  
{ &:<, c12  
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try{ u"`*DFjo*  
URL url = new URL(sURL); *7ZtNo[+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #.H}r6jqs  
httpConnection.setRequestProperty("User-Agent","NetFox"); X3<K 1/<  
String sProperty = "bytes="+nStartPos+"-"; {=67XrWN1  
httpConnection.setRequestProperty("RANGE",sProperty); 8f|98T"  
Utility.log(sProperty); j C)-`_  
l
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InputStream input = httpConnection.getInputStream(); V7EQ4Om:It  
//logResponseHead(httpConnection); 5X#E@3g5  
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byte[] b = new byte[1024]; ,beS0U]  
int nRead; yrnv!moc%t  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `rlk|&T1  
{ 0]B(a  
nStartPos += fileAccessI.write(b,0,nRead); ?^}_j vT  
//if(nThreadID == 1) 7b,(\Fm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZIDbqQu  
} _|A+) K  
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Utility.log("Thread " + nThreadID + " is over!"); y\D=Z N@  
bDownOver = true; <.bRf  
//nPos = fileAccessI.write (b,0,nRead); 1Ipfw  
}
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catch(Exception e){e.printStackTrace ();} %Ds+GM-  
} Ab2Q \+,  
} I-kWS4  
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m  
8PBvV[  
//打印回应的头信息 ?T!)X)A#  
public void logResponseHead(HttpURLConnection con) yz8jU*H  
{ ml0*1Dw  
for(int i=1;;i++) Z.1> kZ  
{ 6@V~0DG  
String header=con.getHeaderFieldKey(i); v7,$7@$:\  
if(header!=null) 6~xBi(m`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ls}7VKl'  
Utility.log(header+" : "+con.getHeaderField(header)); l$XPIC~H  
else Rko M~`CT  
break; .UQE{.?  
} i{Ds&{  
} UE.4qY_7  
, jU5|2  
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public void splitterStop() ,[e\cnq[  
{ @1:0h9%  
bStop = true; Z6Fp\aI8@  
} !q' 4D!I  
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} ++jAz<46  
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/* G^;>8r  
**FileAccess.java 5T?-zFMM  
*//文件访问(定位，写) Kr-G{b_Pp  
package NetFox; WQ6"0*er  
import java.io.*; ba@ctkCW  
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public class FileAccessI implements Serializable{ NxA)@9Q  
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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 4vWkT8HQ  
RandomAccessFile oSavedFile; =d)-Fd2li  
long nPos; @t*t+Vqw  
])}]/Qw  
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public FileAccessI() throws IOException }H"kU2l  
{ eE@&ze>X  
this("",0); [eUf
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} fo0+dzazY  

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public FileAccessI(String sName,long nPos) throws IOException OLC{iD#  
{ )"+2Z^1-  
oSavedFile = new RandomAccessFile(sName,"rw"); T~:|!`  
this.nPos = nPos; ])}(k
 
oSavedFile.seek(nPos); $O)3q $|  
} cyM-)r@YQV  
9DQ
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public synchronized int write(byte[] b,int nStart,int nLen) %w7pkh,  
{ |r%D\EB  
int n = -1; OEx^3z^  
try{ hC <O`|lF  
oSavedFile.write(b,nStart,nLen); v<Kmq-b  
n = nLen; U}k9 Py  
} =#gEB#$x:  
catch(IOException e) wU\s; dK  
{ 4m)OR  
e.printStackTrace (); jPZa
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} 67SV~L#%O  
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return n; *+)AqKP\Kv  
} XolZonJr  
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} ?';OD3-  
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/* $-}e; VZb  
**SiteInfoBean.java *^%Q0mU[  
*/ I/gjenUK  
package NetFox; qt%D'  
b` Hz$8  
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public class SiteInfoBean { 1K,1X(0rL8  
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private String sSiteURL; //Site's URL L@`ouQ"sa  
private String sFilePath; //Saved File's Path VA*
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private String sFileName; //Saved File's Name D^%^xq)E  
private int nSplitter; //Count of Splited Downloading File w@JKl5  
ABE@n%|`  
:
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public SiteInfoBean() I$N8tn+E  
{//nSplitter的缺省值为5 t58e(dgi  
//default value of nSplitter is 5 )9l^O  
this("","","",5); !l]dR@e  
} Wjhvxk  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <\k
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{ iu&wO<)+?  
sSiteURL= sURL; AKMm&(fh%  
sFilePath = sPath; ^P151*=D  
sFileName = sName; nWQ;9_qBB  
this.nSplitter = nSpiltter; ;qH
OOT  
`W/sP\3  
#Zrlp.M4  
} =] *.ZH#h  
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public String getSSiteURL() F1L:,.e`  
{ a:QDBS2Llv  
return sSiteURL; Uf}\p~;  
} C4TE-OM8  
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public void setSSiteURL(String value) |$5[(
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{ 3U_2!zF3_  
sSiteURL = value; a7N!B'y  
} 3Zi@A4Wu  
k
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6G=j6gK%P  
public String getSFilePath() M1KqY:9E  
{ -D6exTxh"  
return sFilePath; ZXm/A0)S  
} 4:gRr   
}.s~T#v  

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public void setSFilePath(String value) |4'Y/re  
{ y+7w,m2  
sFilePath = value; ~NW32 O)/  
} zOQ>d|p?X  
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public String getSFileName() c y8;@[#9  
{ lRXK\xIP ,  
return sFileName; 8By|@LO  
} eq UME  
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0,  
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public void setSFileName(String value) ;Iq/l%vX  
{ l+V>]?j  
sFileName = value; K4kMM*D  
} ,G)r=$XU  
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*QH28%^  
public int getNSplitter() ynbuN x*  
{ t.;LnrY  
return nSplitter; ~?(N  
} rS;Dmm  
7Hs%Cc"  
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public void setNSplitter(int nCount) I'LnI*  
{ 1')%`~  
nSplitter = nCount; '3g[]M@M  
} b9!FC$^J  
} WYr/oRO  
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*c2YRbU(  
/* lv04g} W  
**Utility.java soQ1X@"0  
*/ >rf'-X4n  
package NetFox; |j,"Pl}il^  
d QqK^#  
jbAx;Xt'=M  
public class Utility { OynXkH]0T+  
<[-nF"Q  
pS:4CNI{  
public Utility() o,)?!{k}  
{ ;5)P6S.D  
]?(-[  
B8}Nvz /  
} ajEjZ6  
@<elq'2  
//线程睡眠 Fx2bwut.K  
public static void sleep(int nSecond) yPal
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{ 3qf Ym}d  
try{ U[ 0=L`0e  
Thread.sleep(nSecond); va0{>Dc+  
} jEZMUqGY!  
catch(Exception e) N(Tz%o4  
{ WH
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e.printStackTrace (); tIuCct-  
} .?loO3 m  
} :s7m4!E
F  
\hx1o\  
//日志 c_4[e5z  
public static void log(String sMsg) ^y<<>Y'I  
{ ci?qT
,&  
System.err.println(sMsg); tg<EY!WY  
} vbyH<LPz5  
3v1iy/ /  
UdpF@Q  
public static void log(int sMsg) <4HDZ{"M  
{ gMzcTmbc8  
System.err.println(sMsg); 75XJL;W #  
} kH G"XTL  
} Q
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&B6Ep6QS  
f,018]|  
/* X\bOz[\  
**TestMethod.java ;)D];u|_  
*/ M`,)wi  
package NetFox; OCBgR4I  
JzQ)jdvp  
uM_wjP  
public class TestMethod { @`q:IIgW  
h4T5+~rw  
6\g cFfo  
public TestMethod() qVH1}9_  
{ ///xx/weblogic60b2_win.exe .\)U@L~  
try{ xc=b |:A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); CxwoBuG=?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `erV$( M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /`wvxKX  
fileFetch.start(); PHZ0P7  
} @~^5l  
catch(Exception e){e.printStackTrace ();} J  IUx  
JB<Sl4  
um!J]N^  
} ,$s8GAmq  
n\*!CXc  
|)(VsVG&  
public static void main(String[] args) E&2OD [iX  
{ S4Y&  
new TestMethod(); u)}$~E>  
} UC]\yUK1J  
} 0IBhb(X  
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