http断点续传简单实现（java)

/* TA5M4r6  
**SiteFileFetch.java #UIg<:  
*/ Atw^C+"vW&  
package NetFox; "zc!QHpSd  
import java.io.*; "m5ZZG#R`
 
import java.net.*; Joj
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public class SiteFileFetch extends Thread { l.! ~t1i  
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SiteInfoBean siteInfoBean = null; //文件信息Bean I+SL0  
long[] nStartPos; //开始位置 ^&%?Q_]  
long[] nEndPos; //结束位置 iV=#'yY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L3\{{QOA  
long nFileLength; //文件长度 n\4+xZr  
boolean bFirst = true; //是否第一次取文件 AS;{{^mM(  
boolean bStop = false; //停止标志 ~XRr }z_Lq  
File tmpFile; //文件下载的临时信息 suwj1qYJ4  
DataOutputStream output; //输出到文件的输出流 7[\B{N9&W  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） To+{9"$,  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8*ysuL#  
{ xPv&(XZR  
siteInfoBean = bean; h&{pMmS3
,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W` V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); w,7 GC5j\  
if(tmpFile.exists ()) 3z<t#  
{ t
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bFirst = false; `,O^=HBM  
read_nPos(); zb(u?U  
} +TX]~k79Oq  
else =&'j;j  
{ OZ&aTm :  
nStartPos = new long[bean.getNSplitter()]; KN=Orx7Gy  
nEndPos = new long[bean.getNSplitter()]; }e$);A|  
} F=H=[pSe  
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} rv%Xvs B  
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public void run() wpvaTHo  
{ |bh:x{h  
//获得文件长度 -eya$C  
//分割文件 4^5s\f B  
//实例FileSplitterFetch UJI1n?~  
//启动FileSplitterFetch线程 RK0IkRXQd  
//等待子线程返回 6lPGop]js]  
try{ Q=[&~^Y)  
if(bFirst) C-7.Sa  
{ `i
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nFileLength = getFileSize(); ]iPdAwc.1  
if(nFileLength == -1) j:
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{ uIu0"pv`x  
System.err.println("File Length is not known!"); |v+b?@  
} >jcNo3S  
else if(nFileLength == -2) =uH`EkY:  
{ bCsQWsj^NW  
System.err.println("File is not access!"); s`{O-  
} |@+ x9|'W  
else :;EzvRy  
{ Hd:ZE::Q'#  
for(int i=0;i<nStartPos.length;i++) "6ZatRUd  
{ .d2s4q\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cg4,PI%hz  
} & 3gni4@@  
for(int i=0;i<nEndPos.length-1;i++) rRMC<.=  
{ )}R0'QGd  
nEndPos = nStartPos[i+1]; v1:5r  
} G100L}d"N  
nEndPos[nEndPos.length-1] = nFileLength; ;Wr$hDt^  
} SWu=n1J.?H  
} 84k;d;  
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~7*HZ:.  
//启动子线程 nV<YwqK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Gr_I/+<  
for(int i=0;i<nStartPos.length;i++) QeK~A@|F&  
{ jooh`| `P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X,p&S^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w/R^Vwq  
nStartPos,nEndPos,i); Uc&0>_Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #M
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fileSplitterFetch.start(); ^E9@L??  
} :Q%&:[2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nQ mkDPjU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *I~F7Z]|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e='3gzz  
nEndPos = " + nFileLength); PW}Yts7p  
// fileSplitterFetch[nPos.length-1].start(); d;>:<{z@CD  
#2pgh?  
V!oyC$eV  
//等待子线程结束 `jJb) z3D  
//int count = 0; :Qf^@TS}O  
//是否结束while循环 P<bA~%<7"[  
boolean breakWhile = false; l|DOsI'r  
cu Nwv(P  
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while(!bStop) *e^ZH  
{ j*P@]&e7d  
write_nPos(); sh0O~%]g  
Utility.sleep(500); 1vobfZ-w9  
breakWhile = true; Y}0-&  
/%.K`BMN  
{MIs%w.G  
for(int i=0;i<nStartPos.length;i++) N@k:kI  
{ L-fAT'!'  
if(!fileSplitterFetch.bDownOver) '+`
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{ (\]_/ W  
breakWhile = false; REHfk6YE  
break; <-
$4?}  
} > vgqf>)kk  
} /OViqZ;9  
if(breakWhile) f1JvP\I0Q  
break; /({5x[  
VRD2e ,K  
Blu^\:?#z-  
//count++; Rq;R{a  
//if(count>4) p.zU9rID  
// siteStop(); 0ya_[\  
} 2-8<uUy  
#ujcT%1G  
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System.err.println("文件下载结束！"); ?9AByg  
} #x'C  
catch(Exception e){e.printStackTrace ();} *rA!`e*  
} sO6+L #!  
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}=wSfr9g  
//获得文件长度 #u#s'W  
public long getFileSize() Nz2}M
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{ ZV&=B%J bs  
int nFileLength = -1; %!WQ;(  
try{ wLW!_D,/R  
URL url = new URL(siteInfoBean.getSSiteURL());  }UX>O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JBuorc  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1,4kw~tA  
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!j\yt  
int responseCode=httpConnection.getResponseCode(); ?vvjwys@  
if(responseCode>=400) z.7 UfLV9  
{ _c`Gxt%  
processErrorCode(responseCode); P4s:wuJ^  
return -2; //-2 represent access is error K2NnA  
} IUwY/R9Q  
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String sHeader; S0\:1B  
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for(int i=1;;i++) &bTadd%0  
{ y
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7quhp\  
//Utility.log(in.readLine()); wN;o++6V  
sHeader=httpConnection.getHeaderFieldKey(i); <TDgv%eg0  
if(sHeader!=null) ?eeE[F  
{ ,)%nLc  
if(sHeader.equals("Content-Length")) 9-9`;Z  
{ c_%vD~6W-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F7a\Luae  
break; `$Q $l  
} 24]O0K  
} o:m:9d
n  
else }(ot IqE  
break; M7UVL&_z%  
} P oC*>R8  
} =TU"B-*  
catch(IOException e){e.printStackTrace ();} GN(PH/fO9  
catch(Exception e){e.printStackTrace ();} )R,*>-OPJL  
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Utility.log(nFileLength);  gryC#  
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return nFileLength; 3]/w3|y  
} pl'n 0L<l  
izOtt^#DZt  
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//保存下载信息（文件指针位置） gy,B+~p  
private void write_nPos() qJUu9[3'm  
{ (7&[!PS  
try{ 'lg6<M%#[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9tqX77UK  
output.writeInt(nStartPos.length); fk;39$[  
for(int i=0;i<nStartPos.length;i++) @>&UoH}2  
{ a'W-&j  
// output.writeLong(nPos); -g_PJ.Hk  
output.writeLong(fileSplitterFetch.nStartPos); C {gYrz)  
output.writeLong(fileSplitterFetch.nEndPos); #*XuU8q?  
} 8+Oyhd*|  
output.close(); 3/P
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} 0vf2wBK'T  
catch(IOException e){e.printStackTrace ();} NkA|T1w7  
catch(Exception e){e.printStackTrace ();} n*hHqZl  
} ?tg(X[h{S  
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//读取保存的下载信息（文件指针位置） x~Y]c"'D  
private void read_nPos() ,accw}G  
{ ?HAWw'QW  
try{ |'Z6M];8t  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); n:x6bPal]  
int nCount = input.readInt(); NqVe{+1x  
nStartPos = new long[nCount]; _.yBX\tf[  
nEndPos = new long[nCount]; =X]$J@j  
for(int i=0;i<nStartPos.length;i++) >@`D@_v  
{ ]t(;bD hT  
nStartPos = input.readLong(); \k;*Ej~.  
nEndPos = input.readLong(); rt^<=|Z  
} !ku5
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input.close(); [r<lAS{ .  
} VYMs`d[  
catch(IOException e){e.printStackTrace ();} c"H*9u:  
catch(Exception e){e.printStackTrace ();} s^)wh v`C  
} 5$`ihO?  
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private void processErrorCode(int nErrorCode) ;gP@d`s  
{ XN'x`%!*3#  
System.err.println("Error Code : " + nErrorCode); 9YwK1[G6/  
} s:~3|D][  
#0zMPh /U}  
IhhB^E|  
//停止文件下载 uwU;glT  
public void siteStop() L?23Av0W  
{ cL?FloPc*  
bStop = true; M\ B A+  
for(int i=0;i<nStartPos.length;i++) j:0(=H!#  
fileSplitterFetch.splitterStop(); gR )xw)!  
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} tn>$5}^;  
} ^`!5!|  
//负责部分文件的抓取 ]*'V#;s  
**FileSplitterFetch.java NffZttN  
*/ {|9x*I  
package NetFox; q$Gf9&ZO  

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import java.io.*; nB[Aw7^|A  
import java.net.*; 0hp*(, L  
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public class FileSplitterFetch extends Thread { }uz*6Z(S  
FFQ=<(Ki  
7Y"CeU-S  
String sURL; //File URL / q*n*j  
long nStartPos; //File Snippet Start Position
U ]Ek5p  
long nEndPos; //File Snippet End Position 8!(4;fN$j.  
int nThreadID; //Thread's ID ?ey!wcv~  
boolean bDownOver = false; //Downing is over mR\rK&'6  
boolean bStop = false; //Stop identical ^rO3B?_  
FileAccessI fileAccessI = null; //File Access interface Vv8e"S  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ztu _UlGC  
{ 8+5z-vd  
this.sURL = sURL; uQIa"u7  
this.nStartPos = nStart; WqlX'tA  
this.nEndPos = nEnd;  ky0Fm W  
nThreadID = id; J5b>mTvb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;'CWAJK  
} 16Ym*kWIps  
V<A_c^unO  
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public void run() C]59@z;+bN  
{ E2+x?Sc+  
while(nStartPos < nEndPos && !bStop) ^@5#jS2  
{ I CCmE#n  
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try{ c'ExZ)RJ  
URL url = new URL(sURL); J\VG/)E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^LO=&Cq  
httpConnection.setRequestProperty("User-Agent","NetFox"); nK=-SQ  
String sProperty = "bytes="+nStartPos+"-"; f_y+B]?'M  
httpConnection.setRequestProperty("RANGE",sProperty); k`[ L  
Utility.log(sProperty); u2%/</]h  
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InputStream input = httpConnection.getInputStream(); l?F
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//logResponseHead(httpConnection); Ss ;C1:  
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byte[] b = new byte[1024]; = zJY5@^'7  
int nRead; UlF=,0P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9U$n;uA  
{ j{PuZ^v1  
nStartPos += fileAccessI.write(b,0,nRead); [+dOgyK  
//if(nThreadID == 1) v,qK=]ty  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DY<Br;  
} K.'II9-{  
OT/*|Pn9  
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Utility.log("Thread " + nThreadID + " is over!"); 0kEzi  
bDownOver = true; gwHNz5 a*V  
//nPos = fileAccessI.write (b,0,nRead); TNs;#Q  
} }$EcNm$%  
catch(Exception e){e.printStackTrace ();} >5G2!Ns'  
} $#E?`At{I  
} CDOqdBQ  
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//打印回应的头信息 $$QbcnOf$  
public void logResponseHead(HttpURLConnection con) 2\ 3}y(  
{ (NPDgR/  
for(int i=1;;i++) qC<!!473?  
{ $7 1(g$6#  
String header=con.getHeaderFieldKey(i); ETQ.A< v  
if(header!=null) H
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); DY]\@<ez  
Utility.log(header+" : "+con.getHeaderField(header)); Gc6`]7 s  
else eF)vx{s  
break; DSiI%_[Ud  
} <tp\+v!u  
} =fy~-FN_  
,#;%ILF4%  
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public void splitterStop() "7Qc:<ww  
{ 0{u31#0j
 
bStop = true; ^]Mlkd:  
} }ti+tM*  
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} gHCk;dmq81  
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-?)` OHc^  
/* NY]`1yy  
**FileAccess.java Zr!he$8(2  
*//文件访问(定位，写) (W.euQy  
package NetFox; erG@8CG  
import java.io.*; @H'pvFLK?  
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public class FileAccessI implements Serializable{ sR%,l  
8'c_&\kdv  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
-4:L[.2  
RandomAccessFile oSavedFile; 8GC(?#Kb  
long nPos; 5|zISK%zHS  
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{-X8MisI  
public FileAccessI() throws IOException P=ARttT`(  
{ %DJxUuh  
this("",0); K&{*sa r  
} 3'(w6V  
@r.u8e)l  
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public FileAccessI(String sName,long nPos) throws IOException fG;(&Dx  
{ 'MEO?]Tf.^  
oSavedFile = new RandomAccessFile(sName,"rw"); ?V|t7^+:  
this.nPos = nPos; P
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oSavedFile.seek(nPos); +/idq  
} mRIW9V  
JvFU7`4@  
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public synchronized int write(byte[] b,int nStart,int nLen) &W1{o&  
{ 9p,<<5{  
int n = -1; v&CKtk!3{  
try{ T?=[6  
oSavedFile.write(b,nStart,nLen); F[ca4_lK  
n = nLen; RU`m|<  
} ~;aSE  
catch(IOException e) neC]\B[Xm  
{ e<|'   
e.printStackTrace (); enu",wC3  
} ,$ICv+7]  
<{\U
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return n; !?Tu pi  
} n1Ag o3NM  
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} E|f&SEnzK  
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/* VN=S&iBa/  
**SiteInfoBean.java WZ"g:Khw  
*/ #N-N
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package NetFox; qx! NU}6  
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public class SiteInfoBean { V%~u8b  
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private String sSiteURL; //Site's URL =Ewa}$-  
private String sFilePath; //Saved File's Path l\8l.xP  
private String sFileName; //Saved File's Name ldJeja~Xl  
private int nSplitter; //Count of Splited Downloading File ],%}}UN  

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-Kt36:|  
public SiteInfoBean() _tE$a3`  
{//nSplitter的缺省值为5 mea]m)P  
//default value of nSplitter is 5 Gq5)>'D?  
this("","","",5); >M7e'}0;  
} u(KeS`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r\+AeCyb"p  
{ "HR &Rf k  
sSiteURL= sURL; {rr ED  
sFilePath = sPath; ~Ra1Zc$o:  
sFileName = sName; IXp P.d  
this.nSplitter = nSpiltter; L4SvE^2+  
:SSlUl4sU$  
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} ;(3fr0cr:  
>gDsjHQ6;  
_nRY5YnL4P  
public String getSSiteURL() /Ny/%[cu  
{ >u5}5OP7  
return sSiteURL; dL"$YU9z  
} {]-nYHGL  
jr"~  
{m}B=u  
public void setSSiteURL(String value) ih1s`CjG  
{ 7I4G:-V:^  
sSiteURL = value; hIa@JEIt  
} ,2?"W8,  
gDnG!i+  
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public String getSFilePath() /= P!9d {  
{ Ov%9S/d  
return sFilePath; /B!"\0G/,  
} \@4QG.3&  
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d; @Kz^  
public void setSFilePath(String value) 9a)D
8  
{ Dbyy H_  
sFilePath = value; _p{ag 1gP  
} />\.zuAr&  
J.
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 6" 3!9JC  
public String getSFileName() ^~MHxF5d  
{ (FMGW (  
return sFileName; /S9Mu )1Y  
} R4}G@&Q  
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7w)#[^  
public void setSFileName(String value) zE.4e&m%Z?  
{ {NE;z<,*:  
sFileName = value; 
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} 7K9+7I&C  
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public int getNSplitter() :KX/GN!n  
{ I?-9%4 8iM  
return nSplitter; Ltcr]T(Ic  
} ..;LU:F  
(B]Vw+/  
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public void setNSplitter(int nCount) %8 cFzyE*  
{ F>A-+]X3o  
nSplitter = nCount; IG +nr
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} }SpMHR`  
} ?Pmj}f  
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/* GLc+`,.  
**Utility.java Kr]!B
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*/ N!RyncJ  
package NetFox; Jc9SHCJ  
? dSrY  
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public class Utility { ,O a)  
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public Utility() aDza"Ln  
{ 94nvh:n  
Xg!Mc<wA[  
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} u#=N8
 

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//线程睡眠 Vzbl*Zmx  
public static void sleep(int nSecond) @292;qi  
{ Y/Y746I  
try{ lt0(Kf g  
Thread.sleep(nSecond); b'9G`Y s^  
} ~,':PUkiV  
catch(Exception e) %I Y-0\  
{ &B3\;|\  
e.printStackTrace (); [+GQ3Z\  
} T_AZCl4d  
} k~=-o>}C  
|BYD]vK  
//日志 E?Q=#+}U  
public static void log(String sMsg) <;9vwSH>  
{ b@,=;Y)O  
System.err.println(sMsg); ,b{G(sF  
} RSmxwx^  
MiOSSl};  
zi*D8!_C  
public static void log(int sMsg) B0Z*YsbXL  
{ L4kYF~G:4  
System.err.println(sMsg); W97Ka}Y  
} >+oQxml6nI  
} Vp5qul%  
I8^z\ef&  
YVW!u6W'[6  
/* T/S-}|fhQ  
**TestMethod.java ,u]kZ]  
*/ J_P2%b=C  
package NetFox; m@HU;J\I  
XTW/3pB  
}3[ [ONA  
public class TestMethod { bJ. ((1$  
>Ckb9A  
$ HUCp9  
public TestMethod() 3v0
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{ ///xx/weblogic60b2_win.exe Nt/*VYUn  
try{ HM[BFF[;/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kFk+TXLDIt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O~aS&g/sf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RNvtgZ}k{X  
fileFetch.start(); de ](l687I  
}  pd X9G  
catch(Exception e){e.printStackTrace ();} OZt'ovY  
t]vX9vv+D  
;#xhlR* ~  
} ?'_iqg3  
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public static void main(String[] args) T,?^J-h^  
{ ',
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new TestMethod(); xOu cZ+  
} ,hOJe=u46  
} 7?hCt  
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