http断点续传简单实现（java)

/* wxU@M1w}  
**SiteFileFetch.java 3.>M=K~09  
*/ T9N][5\  
package NetFox; yXyL,R  
import java.io.*; Wv!#B$J~U  
import java.net.*; [S;ceORx  
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public class SiteFileFetch extends Thread { +Q
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SiteInfoBean siteInfoBean = null; //文件信息Bean },<(VhP  
long[] nStartPos; //开始位置 %X)w$}
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long[] nEndPos; //结束位置 Q'D%?Vg'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6jz6   
long nFileLength; //文件长度 xe9E</M_  
boolean bFirst = true; //是否第一次取文件 SbS*z:  
boolean bStop = false; //停止标志 V
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File tmpFile; //文件下载的临时信息 .)J7 \z8m  
DataOutputStream output; //输出到文件的输出流 ;Qe-y|>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2loy4f  
public SiteFileFetch(SiteInfoBean bean) throws IOException h$
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{ l12Pj02w  
siteInfoBean = bean; #pDWwnP[rt  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /,#HGu]q'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =GH>-*qp  
if(tmpFile.exists ()) SStaS<q'  
{ 2:b3+{\f  
bFirst = false; {yFCGCs  
read_nPos(); %@Mv-A6)  
} v;_m1UpuW  
else `wIMu$i  
{ W%Jw\ z=  
nStartPos = new long[bean.getNSplitter()]; &d}1)?  
nEndPos = new long[bean.getNSplitter()]; kF{'?R5w  
} #_oN.1u57  
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} 'YKyY:eZ  
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public void run() WTWONO>  
{ b2rlj6d  
//获得文件长度 -lICoRO#  
//分割文件 Fl8*dXG&  
//实例FileSplitterFetch I?y!d G  
//启动FileSplitterFetch线程 H{yUKZH*  
//等待子线程返回 %0-fn'  
try{ \mGx-g6  
if(bFirst) :'hc&wk`  
{ ">zK1t5=  
nFileLength = getFileSize(); Tnd)4}2p  
if(nFileLength == -1) 2H\}N^;f  
{  8kn> ?  
System.err.println("File Length is not known!"); aL?+# j^"  
} /?(\6Z_A  
else if(nFileLength == -2) 6b!F7kyg  
{ tNk.|}  
System.err.println("File is not access!"); GhlbYa  
} 0Ncx':]5  
else UQ[!k 6  
{ r1pj-   
for(int i=0;i<nStartPos.length;i++) {Sl#z}@s  
{ ,Q%q!#@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); z?Hi u6c-  
} /2s=;tA1  
for(int i=0;i<nEndPos.length-1;i++) 2lb HUK  
{ X%>nvp  
nEndPos = nStartPos[i+1]; -q&K9ZCl`  
} r^g"%nq9/  
nEndPos[nEndPos.length-1] = nFileLength; 9K4]~_%h\  
} x`3F?[#l  
} ab-z 7g  
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//启动子线程 >_3P6-L>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; FGRdA^`  
for(int i=0;i<nStartPos.length;i++) P]A~:Lj  
{ +Oxw?`I$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0gevn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -!bf
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nStartPos,nEndPos,i); 4`X]$.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b7uxCH]Z  
fileSplitterFetch.start(); Cf~vT"  
} ;xXD2{q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ffH]`N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J]AkWEiCJ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", J=l\t7w  
nEndPos = " + nFileLength); fo$s9g^<  
// fileSplitterFetch[nPos.length-1].start(); `<#Ufi*c  
xU6rZCqE  
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//等待子线程结束 S' <X)  
//int count = 0; 6P$jMjs  
//是否结束while循环 uUIjntSF(  
boolean breakWhile = false; 1#w'<}h#U  
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while(!bStop) {9c_T!c  
{ jtH>&O  
write_nPos(); ev
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Utility.sleep(500); =JW.1;  
breakWhile = true; E*"-U!?)l2  
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}+/F?_I= %  
for(int i=0;i<nStartPos.length;i++) J/k4CV*li(  
{ '=V1'I*  
if(!fileSplitterFetch.bDownOver) S%6V(L|  
{ eaWK2%v  
breakWhile = false; Z@ dS,M*  
break; hY(q@_s  
} B]nu \!  
} EYy|JT]B  
if(breakWhile) }i F|NIV  
break; oC  }  
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vEZd;40y  
//count++; XS_Ib\-50  
//if(count>4) v(GT+i)|  
// siteStop(); qX"m"ko  
} ugy:^U  
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System.err.println("文件下载结束！"); zI&).  
} k:yrh:JhB  
catch(Exception e){e.printStackTrace ();} Rq[VP#  
}  QUb#84  
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//获得文件长度 /R
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public long getFileSize() (GJX[$@  
{ 6DxT(VU}  
int nFileLength = -1; cs-dvpMZ  
try{ [ApAd  
URL url = new URL(siteInfoBean.getSSiteURL()); @wTRoMHPQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2tMa4L%@C  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~&7 *<`7{  
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int responseCode=httpConnection.getResponseCode(); 6xW17P  
if(responseCode>=400) p9
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{ `]$H\gNI[8  
processErrorCode(responseCode); ,AuejMd  
return -2; //-2 represent access is error /8[T2Z!  
} xN>+!&3%w  
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String sHeader; BnPL>11Y  
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for(int i=1;;i++) j=V2~ xA6  
{ )%Lgo${[;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); HI!bq%TZ4  
//Utility.log(in.readLine()); dx)v`.%V  
sHeader=httpConnection.getHeaderFieldKey(i); [W--%=Ou  
if(sHeader!=null) #(dERET*  
{ F m$;p6&j  
if(sHeader.equals("Content-Length")) ^!x}e+ o  
{ c]3^2Ag,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); rCn"{.rI  
break; 'qlWDt/  
} gVpp9VB  
} +l@+e_>  
else v>'mW  
break; gH[lpRu|7  
} 39Zs  
} />[~2d kb  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} c 6$n:  
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Utility.log(nFileLength); 9 ?(P?H  
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return nFileLength; fS- 31<?  
} h@D</2>  
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//保存下载信息（文件指针位置） pNzpT!}H>  
private void write_nPos() xx EcmS#>  
{ HHae
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try{ O\[Td  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BGZvgMxLJ  
output.writeInt(nStartPos.length); /u N3"m5i  
for(int i=0;i<nStartPos.length;i++) 7).zed^  
{ 2apQ4)6#[H  
// output.writeLong(nPos); 
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output.writeLong(fileSplitterFetch.nStartPos); pTzfc`~xv  
output.writeLong(fileSplitterFetch.nEndPos); '$5o5\  
} GcA!I!j/  
output.close(); a&~]77)  
} CJ 9tO#R  
catch(IOException e){e.printStackTrace ();} Bl8&g]dk  
catch(Exception e){e.printStackTrace ();} hXM2B2[  
} MESPfS+  
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//读取保存的下载信息（文件指针位置） o]@g%_3X  
private void read_nPos() m8ydX6~max  
{ lITZ|u  
try{ ]Zz<9zix  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *|Fl&`2  
int nCount = input.readInt(); Or[uq,Dm16  
nStartPos = new long[nCount]; 7LdNE|
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nEndPos = new long[nCount]; ne\N1`AU  
for(int i=0;i<nStartPos.length;i++) y$7@~NH,d  
{ rXR}]|;>  
nStartPos = input.readLong(); L7&|  
nEndPos = input.readLong(); L~~Dj:%uq  
} gHzjI[WI  
input.close(); L7qlvS Q  
} >5!/&D.q  
catch(IOException e){e.printStackTrace ();} J"dp?i  
catch(Exception e){e.printStackTrace ();} ALY% h!L  
} vX
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private void processErrorCode(int nErrorCode) 59I}  
{ Bt^];DjH  
System.err.println("Error Code : " + nErrorCode); `[J(au$z  
} #O.-/&Z  
b1{XGK'  
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//停止文件下载 yYvv;E  
public void siteStop() sP NAG  
{ > AV R3b  
bStop = true; jn;b{*Lf  
for(int i=0;i<nStartPos.length;i++) Y)L\*+ >"[  
fileSplitterFetch.splitterStop(); 5bzYTK&-  
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} +6* .lRA  
} AH(O"v`  
//负责部分文件的抓取 b!' bu  
**FileSplitterFetch.java :4D#hOI  
*/ 7l})`> k  
package NetFox; 4IYC;J2L  
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import java.io.*; d4P0f'.z  
import java.net.*; !u#o"e<qh  
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public class FileSplitterFetch extends Thread { Ueyt}44.e2  
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String sURL; //File URL =`X;fz  
long nStartPos; //File Snippet Start Position )LYj,do  
long nEndPos; //File Snippet End Position ab 1\nzpd  
int nThreadID; //Thread's ID &xqe8!FeA  
boolean bDownOver = false; //Downing is over : |c,.uO  
boolean bStop = false; //Stop identical :l>T~&/98  
FileAccessI fileAccessI = null; //File Access interface cF[[_  
B|O/h!H.  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yf=ek==  
{ 9e Dji,  
this.sURL = sURL; ;61m  
this.nStartPos = nStart; lC1X9Op  
this.nEndPos = nEnd; xy|-{  
nThreadID = id; GfQP@R"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /j'We-C  
} ZtEHP`Iin  
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public void run() Iq\sf-1E  
{ 6iFd[<.*j  
while(nStartPos < nEndPos && !bStop) b['TRYc=:  
{ ):
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try{ Z3R..vy
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URL url = new URL(sURL); )vS##-[_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A?;/]m;  
httpConnection.setRequestProperty("User-Agent","NetFox"); rDYq]`  
String sProperty = "bytes="+nStartPos+"-"; o0wep&@  
httpConnection.setRequestProperty("RANGE",sProperty); w'5~GhnP+  
Utility.log(sProperty); xL>0&R  
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InputStream input = httpConnection.getInputStream(); 5Tpn`2F  
//logResponseHead(httpConnection); 2+GF:[$  
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@ z#k~  
byte[] b = new byte[1024]; SAG)vmm  
int nRead; (>0d+ KT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -lMC{~h\(S  
{ nwN<Q\]S  
nStartPos += fileAccessI.write(b,0,nRead); KX<RD|=  
//if(nThreadID == 1) jVRd[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X2i<2N*@  
} eS@RA2  
mc(&'U8R0I  
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Utility.log("Thread " + nThreadID + " is over!"); \lR~!6:  
bDownOver = true; XpH[SRUx  
//nPos = fileAccessI.write (b,0,nRead); BJj~fNm1Zr  
} 3 XfXMVm  
catch(Exception e){e.printStackTrace ();} SsznV}{^  
} mk4%]t"  
} jd2Fh):q  
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//打印回应的头信息 'KQuz)-  
public void logResponseHead(HttpURLConnection con) g\(7z P  
{ wKY6[vvF  
for(int i=1;;i++) RFK N,oB  
{ \\)-[4uC  
String header=con.getHeaderFieldKey(i); /2HwK/RZ  
if(header!=null) %k$C
   
//responseHeaders.put(header,httpConnection.getHeaderField(header)); dIO\ lL   
Utility.log(header+" : "+con.getHeaderField(header)); }UGPEf\  
else J*U(f{Q(  
break;  74Q?%X  
} g>im2AD+e  
} ^1cqx]>E  
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public void splitterStop() ^m1Rw|  
{ .X2mEnh  
bStop = true; c>UITM=!I  
} 2CxdNj  
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e#'`
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} KFV]2mFN  
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/* pb{P[-f  
**FileAccess.java 5e2mEQU>  
*//文件访问(定位，写) [ objdQU`  
package NetFox; D9LwYftZ  
import java.io.*; ;C"J5RA  
sG VC+!E  
zWY6D4   
public class FileAccessI implements Serializable{ &erNVD5o  
5;^8wh(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,Xh4(Gn#b  
RandomAccessFile oSavedFile; d=5D 9'+  
long nPos; Zh(f2urKV  
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public FileAccessI() throws IOException 1QN]9R0`#7  
{ W.67, 0m$  
this("",0); ^2??]R&Q  
} Zka;}UL&Q  
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public FileAccessI(String sName,long nPos) throws IOException gEe}xI  
{ }%1E9u  
oSavedFile = new RandomAccessFile(sName,"rw"); %d7iQZb>  
this.nPos = nPos; ZbGyl}8ua  
oSavedFile.seek(nPos); isd[l-wAmf  
} LTY.i3  
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public synchronized int write(byte[] b,int nStart,int nLen) uo{QF5z]  
{ =az$WRV+7!  
int n = -1; aFSZYyPxwv  
try{ |(V%(_s  
oSavedFile.write(b,nStart,nLen); Ml3F\ fAW  
n = nLen; ^4fkZh  
} ;,A\bmC  
catch(IOException e) B#DV<%GPl  
{ l1:j/[B=  
e.printStackTrace (); /.?\P#9)  
} DuE>KX{<!R  
)3 r1; ^W  
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return n; M)xK+f2_[  
} )b7mzDp(  
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} *= 71/&B  
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dg!sRm1iZ:  
/* UEeqk"t^  
**SiteInfoBean.java uJO
*aA{K  
*/ /Yh([P>  
package NetFox; Ya. $x~  
u<8Q[_E&  
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public class SiteInfoBean { P:=ADW c  
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private String sSiteURL; //Site's URL s_[?(Ip{  
private String sFilePath; //Saved File's Path S3<v?tqLr  
private String sFileName; //Saved File's Name v\ox:C  
private int nSplitter; //Count of Splited Downloading File X"0Q)  
f/B--jq  
9j"\Lr*o"  
public SiteInfoBean() Z~|J"2.  
{//nSplitter的缺省值为5 !+6l.`2WI  
//default value of nSplitter is 5 0%t|?@HoN  
this("","","",5); xH0/R LK3J  
} xki"'

  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) TGNeEYr  
{ $>
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sSiteURL= sURL; Jc)1}  
sFilePath = sPath; XJ\q!{;h  
sFileName = sName; 5Z[D(z  
this.nSplitter = nSpiltter; J$Q-1fjj  
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} yU.0'r5uR  
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public String getSSiteURL() Wg%-m%7O  
{ t>fB
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return sSiteURL; {<2ZbN?  
} fUL"fMoU  
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public void setSSiteURL(String value) 6S<$7=$=  
{ O2G+ '  
sSiteURL = value; +XE21hb   
} 6!nb)auVi  
$-Rh
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9zyN8v2  
public String getSFilePath() *K(xES!b  
{ 1I`D$Xq~:  
return sFilePath; 07|NPS  
} B<LavX>F  
+ LwoBn>6  
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public void setSFilePath(String value) *ls6#j@  
{ bwJi[xF  
sFilePath = value; n@Ag`}  
} CnH R&`  
o FLrSmY)E  
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public String getSFileName() VO Qt{v{1|  
{ deoM~r9s  
return sFileName; .y
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} $D5U
#  
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|pqpF?h5|  
public void setSFileName(String value) )US/bC!M$  
{ C=IH
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sFileName = value; b-?o?}*  
} Z?.*.<"Sj  
v+#j>   
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public int getNSplitter() WDdi}i>2  
{ E/ZJ\@gzD  
return nSplitter; ]eW|}V7A:  
} 1Ol]^'y7)  
ugB{2oqi  
i=N\[&
 
public void setNSplitter(int nCount) Wu( 8G  
{ #!jRY!2Vt  
nSplitter = nCount; >!1f`  
} s8[9YfuW  
} 4C%>/*%8>  
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/* rcx;3Vne  
**Utility.java S I7B6c  
*/ dV{Hn {(  
package NetFox; DA$Q-  
^Nw]'e3  
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public class Utility { o%%x'uC  
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public Utility() J&:W4\ m  
{ $ bNe0  
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} _[i=TqVmf  
!rg0U<bO!  
//线程睡眠 @>2rz  
public static void sleep(int nSecond) V6MT>T  
{ H?j-=Zka  
try{ 9>3Ltnn0  
Thread.sleep(nSecond); sBtG}Mo)  
} ~'J 
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catch(Exception e) LGROEn<*d  
{ P0ltN  
e.printStackTrace (); )O@^H  
} !X%!7wsc  
} \'+{X(]  
i @9Qb  
//日志 I"sobZ`  
public static void log(String sMsg) W}k?gg=  
{ P}9Y8$Y>U  
System.err.println(sMsg); &JhIn%=-  
} -ouJf}#R  
kgI=0W>  
@P"`=BU&  
public static void log(int sMsg) ./nYXREO|  
{ udD*E~1q  
System.err.println(sMsg); 7G[ GHc>  
} 7e4tUAiuU  
} SKSAriS~  
A Ok7G?Y  
h0GdFWN  
/* 92aDHECo  
**TestMethod.java 4 uy@ {  
*/ @@/'b'  
package NetFox; J)8pqa   
Ag#5.,B-  
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public class TestMethod { xUo)_P\_  
ys[i`~$  
|<3Q+EB^  
public TestMethod() b6!Q!:GO&  
{ ///xx/weblogic60b2_win.exe ~I\r1Wj;  
try{ _"!{7e`Z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); I0l.KiBm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xeYySM=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2gL[\/s  
fileFetch.start(); /ik)4]>  
} jO&f*rxN  
catch(Exception e){e.printStackTrace ();} E8iadf49  
%<=vbL9  
9(^X2L&Z  
} DtF![0w/  
=o{: -EKQF  
0(9I\j5`TT  
public static void main(String[] args) ~e`;"n@4  
{ {7TJgS  
new TestMethod(); >b4YbLkI#  
} ZU|V+yT  
} >OKS/(I0  
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