http断点续传简单实现（java)

/* 1Yy*G-7}  
**SiteFileFetch.java K@;ls  
*/ `pYL/[5  
package NetFox; &3'zG)  
import java.io.*; Y# ?M%I%j  
import java.net.*; |NaEXzo|qY  
Wx-rW  
Gm'Ch}E  
public class SiteFileFetch extends Thread { B,RHFlp{  
R,[+9U|4V  
iVb#X#  
SiteInfoBean siteInfoBean = null; //文件信息Bean Ix'GP7-m_  
long[] nStartPos; //开始位置 HZzdelo  
long[] nEndPos; //结束位置 5 }F6s  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8:4`q9  
long nFileLength; //文件长度 aW#_"Y}v'  
boolean bFirst = true; //是否第一次取文件 fO$~jxR.  
boolean bStop = false; //停止标志 Y%]&h#F  
File tmpFile; //文件下载的临时信息 qVmG"et'J  
DataOutputStream output; //输出到文件的输出流 &1,qC,:!  
<t4l5nr#  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +G>
;NiP
_  
public SiteFileFetch(SiteInfoBean bean) throws IOException vxx7aPjC  
{ sBD\;\I  
siteInfoBean = bean; K>fY9`Whm  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RBM4_L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vt-53fa|  
if(tmpFile.exists ()) j 1#T]CDs  
{ 'aW<C>  
bFirst = false; s7TV@Y)  
read_nPos(); 5T;,wQ<  
} FR@##i$  
else sy.U]QG  
{ I@9k+JB
  
nStartPos = new long[bean.getNSplitter()]; aj*%$!SU+  
nEndPos = new long[bean.getNSplitter()]; za@`,Yq  
} nFfwVqV  
SvR? nN|  
"Hw%@  
{,rVA(I@  
} +A,t9
3:k  
9K F`9Y  
27Ve$Q8]v  
public void run() O<v9i4*  
{ ^zr]#`@G  
//获得文件长度 |k^ *  
//分割文件 u2xb^vu  
//实例FileSplitterFetch +#!! 'XP  
//启动FileSplitterFetch线程 *T'>-nm]  
//等待子线程返回 H|iY<7@  
try{ .\>I-  
if(bFirst) 1RF? dv  
{ o-jF?9m  
nFileLength = getFileSize(); W+0VrH 0F  
if(nFileLength == -1) ard<T}|N  
{ T=QV =21qn  
System.err.println("File Length is not known!"); 4W''j[Y/  
} 3yfq*\_uXw  
else if(nFileLength == -2) 8Dq;QH}  
{ ?#LbhO*   
System.err.println("File is not access!"); -a[]#v9  
} kt;| $  
else >9.xFiq<  
{ Bld$<uU  
for(int i=0;i<nStartPos.length;i++)  TVP.)%  
{ C  +%&!Q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a!>yX ex  
} ]'F{uDm[  
for(int i=0;i<nEndPos.length-1;i++) *SX'Or,  
{ -PSI^%TR#  
nEndPos = nStartPos[i+1]; '}{J;moB  
} qi\!<clv  
nEndPos[nEndPos.length-1] = nFileLength; ji[O?  
} o0p%j4vac  
} lFNf/j^Z  
q1Si*?2W  
/IS j0"/$  
//启动子线程 =;/4j'1}9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !ACWv*pW  
for(int i=0;i<nStartPos.length;i++) o
AkF  
{ :H$D-pbJ4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pH%cbBm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "bRg_]\q6  
nStartPos,nEndPos,i); ,))UQ7N  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {Tp0#fi  
fileSplitterFetch.start(); $SQ8,Y,  
} 9K@>{69WQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a<%WFix  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u":D{+wC|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }*~EA=YN;  
nEndPos = " + nFileLength); 3:i4DBp,i  
// fileSplitterFetch[nPos.length-1].start(); `CI9~h@k  
@xJ qG"  
%($qg-x  
//等待子线程结束 oQC*d}_E}  
//int count = 0; n<p`OKIV3  
//是否结束while循环 x+vNA J  
boolean breakWhile = false; :5G3uN+\  
r3l}I6  
L!3AiAnr  
while(!bStop) *hAeA+:  
{ <R7*
00  
write_nPos(); {4 !%'~  
Utility.sleep(500); @.gT&H
q  
breakWhile = true; AC=cz!3iB  
mf'N4y%  
jK#y7E  
for(int i=0;i<nStartPos.length;i++) ^CTgo,uf6H  
{ X6~y+R  
if(!fileSplitterFetch.bDownOver) ~1pJQ)!zlq  
{ i+yqsYKO  
breakWhile = false; br}.s@~  
break; 
 O+1e  
} 4@|K^nT`  
} 5M{N-L_eC  
if(breakWhile) 5j`"@C5;O  
break; :tM|$TZ  
S(5.y%"<  
_> .TB\  
//count++; cD8.rRyD  
//if(count>4) ]DdD FLM  
// siteStop(); MQ2gzKw>  
} /a6\G.C5  
2GcQh]ohc  
!h7`W*::  
System.err.println("文件下载结束！"); bvn?wK  
} m?xzx^xs/  
catch(Exception e){e.printStackTrace ();} z-uJ+SA  
} =2bW"gs I  
<\?ySto  
SY["(vP%#  
//获得文件长度 ?)1h.K1}M  
public long getFileSize() H|T:_*5  
{ bOux8OHt*  
int nFileLength = -1;
nG$*[7<0u  
try{ jDcE_55o  
URL url = new URL(siteInfoBean.getSSiteURL()); P6S^wjk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Gp$[u4-6M6  
httpConnection.setRequestProperty("User-Agent","NetFox"); HGB96,o f9  
C;wN>HE  
B+ GPTQSTb  
int responseCode=httpConnection.getResponseCode(); sU4(ed\gI\  
if(responseCode>=400) XcaY'k#  
{ -hL8z
$}  
processErrorCode(responseCode); tQ'E"u1  
return -2; //-2 represent access is error W$N_GR'4  
} d#I'9O0&  
H0 km*5Sn  
kJ>l,AD/  
String sHeader; *f.eyg#  
B c*Rn3i@  
[f.[C5f%"'  
for(int i=1;;i++) t3 *2Z 
u  
{ @= 6}w_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~y_TT5+3  
//Utility.log(in.readLine()); >t'/(y  
sHeader=httpConnection.getHeaderFieldKey(i); (E&}SI~  
if(sHeader!=null) Ws4aCH1  
{
N+b"LZc  
if(sHeader.equals("Content-Length")) rcq(p(!  
{ mR[J Xh9s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); wX#=l?,K  
break; !s?vj
<  
} Cq u/(=  
} sJ7r9O`x  
else j3P)cz-0/L  
break; /t%IU  
} 7w|W\J^7r  
} XkCbdb  
catch(IOException e){e.printStackTrace ();} @?3u|m |Z  
catch(Exception e){e.printStackTrace ();} . CLiv  
K;_p>bI5  
4bhm1Q  
Utility.log(nFileLength); C z4"[C`;  
E4HG`_cWb  
ZBdZr  
return nFileLength; JQ%e'  
} ^EjZ.#2l;  
2 Nr j@q  
x7t<F4  
//保存下载信息（文件指针位置） IpoZ6DB$  
private void write_nPos() }7g\1l\  
{ &rorBD 5aj  
try{ zr\I1v]?1#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2l{g$44  
output.writeInt(nStartPos.length); 4M6o+WV  
for(int i=0;i<nStartPos.length;i++) :upi2S_e  
{ zW!3>(L/  
// output.writeLong(nPos); giyKEnP  
output.writeLong(fileSplitterFetch.nStartPos); 'vhgR2/  
output.writeLong(fileSplitterFetch.nEndPos); sn+i[  
} J1 a/U@"  
output.close(); hc"+6xc  
} it,i^32|  
catch(IOException e){e.printStackTrace ();} ,6}HAC $  
catch(Exception e){e.printStackTrace ();} :tedtV~  
} 4G;+ETp  
@%O"P9;s  
WT;=K0W6&  
//读取保存的下载信息（文件指针位置） &AU%3b  
private void read_nPos() LU?X|{z  
{ xA`Q4"[I  
try{ ZQD_w#0j  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6U @3 xU`  
int nCount = input.readInt(); $`i$/FE  
nStartPos = new long[nCount]; ?#<Fxme  
nEndPos = new long[nCount]; NC>rZS]  
for(int i=0;i<nStartPos.length;i++) '8 1M%KO  
{ ;? '`XB!  
nStartPos = input.readLong(); Zuo7MR  
nEndPos = input.readLong(); {[jcT>.3j  
} y{uRh>l  
input.close(); w+=>b  
} 2wlrei  
catch(IOException e){e.printStackTrace ();} )xiic3F  
catch(Exception e){e.printStackTrace ();} SJ6lI66OX  
} d0Py[37V  
HN7(-ml=B  
\wCj$-;Jt  
private void processErrorCode(int nErrorCode) J|W~\(W6i  
{ K,&)\r kzD  
System.err.println("Error Code : " + nErrorCode); Y1rU  
} `l9Pk\X[  
Pg{Dy>&2`I  
}W#Gf.$6C  
//停止文件下载 [D[s^<RJs  
public void siteStop() ~=lm91W   
{ xlp^XT6#  
bStop = true; X-|`|>3E  
for(int i=0;i<nStartPos.length;i++) 7m~+
HM\  
fileSplitterFetch.splitterStop(); 3Nd&*QSV  
\L}Soe'  
M9.jJf  
} "A~\$  
} f$Nz).(  
//负责部分文件的抓取 .2q7X{4=  
**FileSplitterFetch.java >2x[ub%$L  
*/ *NS:X7p!V  
package NetFox; XpJT
/&4  
&?"(al?  
= 7d{lK  
import java.io.*; Ck%nNy29  
import java.net.*; BD&JbH!(  
6%sX<)n%]  
1\z5[ _  
public class FileSplitterFetch extends Thread { 0UB)FK,9  
8L`J](y  
 )o`|t  
String sURL; //File URL ^q-]."W]t~  
long nStartPos; //File Snippet Start Position |Gx-c ,{{  
long nEndPos; //File Snippet End Position _Jx.?8  
int nThreadID; //Thread's ID \L>3E#R-Q  
boolean bDownOver = false; //Downing is over 2 DJs'"8  
boolean bStop = false; //Stop identical sMlY!3{Ix  
FileAccessI fileAccessI = null; //File Access interface +)k%jIi!  
}dQW-U  
@d:TAwOI'  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g VX  
{ }enm#0Ha  
this.sURL = sURL; % 3d59O  
this.nStartPos = nStart; @W[`^jfQ  
this.nEndPos = nEnd; [`Se
h$  
nThreadID = id; [v( \y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 S+ gzl#r  
} Aj((tMJNOw  
FBJw (.Jr  
h)fJ2]JW8W  
public void run() :c[iS~ ~Y  
{ Z`y%#B6x.  
while(nStartPos < nEndPos && !bStop) -7,xjn  
{ ;)].Dj9  
&o%IKB@  
d#xi_L!  
try{ UfIH!6Q  
URL url = new URL(sURL); n`gW&5,,z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "i0{E!,XL  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~iI4v#0  
String sProperty = "bytes="+nStartPos+"-"; @'>h P  
httpConnection.setRequestProperty("RANGE",sProperty); t1"-3afe  
Utility.log(sProperty); "I+71Ce  
8-]\C  
S bI7<_  
InputStream input = httpConnection.getInputStream(); WX<),u2@  
//logResponseHead(httpConnection); qM%l  
Af y\:&j  
;U$Fz~rJ  
byte[] b = new byte[1024]; 6?\X)qBI  
int nRead; s\&qvL1D  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $bSnbU<  
{ Y,0D+sO4  
nStartPos += fileAccessI.write(b,0,nRead); vt8z=O  
//if(nThreadID == 1) s.ywp{EF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <uq#smY  
} fP 4  
0P)"_x_  
93I.Wp_{  
Utility.log("Thread " + nThreadID + " is over!"); R;D|To!  
bDownOver = true; -aj)
_.d  
//nPos = fileAccessI.write (b,0,nRead); 5}-e9U  
} w K)/m`{g  
catch(Exception e){e.printStackTrace ();} o&-c5X4  
} =?
9z6=  
} lO)-QE+  
{jVEstP  
|Iq#Q3w  
//打印回应的头信息 R|tf}~u !x  
public void logResponseHead(HttpURLConnection con) aG&ay3[&
 
{ Zq[aC0%+  
for(int i=1;;i++) x,LQA0  
{ b@
9>1d$  
String header=con.getHeaderFieldKey(i); iLhxcM2K  
if(header!=null) a
J;6!WFW  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -%I 0Q  
Utility.log(header+" : "+con.getHeaderField(header)); 4<c#3]  
else 'UW]~  
break; pXL@&]U
+  
} b&iJui"7k  
} /U1&#"P  
8y$c\Eu(mF  
v7Q=  
public void splitterStop() (A<'{J#5,  
{ s01W_P.@R  
bStop = true; >o45vB4o  
} s"jNS1B  
85fv])\y  
aNcuT,=(?8  
} HW,2x}[  
uW@o,S0:  
*Y!c6eA  
/* t
93iU?Z  
**FileAccess.java 97XGJ1HI  
*//文件访问(定位，写) B%~D`[~?  
package NetFox; e1d);m$  
import java.io.*; (txr%Z0E  

Q|3SYJf  
k-~HUC.A.  
public class FileAccessI implements Serializable{ (";{@a %  
|N^z=g P[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <kY||  
RandomAccessFile oSavedFile; fBZ\,  
long nPos; ]n/fB|tE  
!uno!wUIYd  
@X\2K?c(v  
public FileAccessI() throws IOException W;^bc*a_  
{ XyM?Dc5,  
this("",0); "q'9-lk  
} Dq~PxcnI  
4h[S`;D0Vf  
#_zd`s3k  
public FileAccessI(String sName,long nPos) throws IOException 4 Ii@_r>  
{ p| #gn<z}  
oSavedFile = new RandomAccessFile(sName,"rw"); |>Xw"]b;  
this.nPos = nPos; CYxrKW l:'  
oSavedFile.seek(nPos); HJ\CGYmyz  
} <;?&<qMo,P  
rX8EXraO  
H=7zd|W  
public synchronized int write(byte[] b,int nStart,int nLen) jE&Onzc  
{ w
|1Gb[  
int n = -1; )kE(%q:*P$  
try{ V r0-/T  
oSavedFile.write(b,nStart,nLen); jJ' LM>e  
n = nLen; CwV1~@{-  
} tv
_Cn w  
catch(IOException e) u D.E>.B  
{ :EUV#5V.  
e.printStackTrace (); 7 %P?3  
} 1qs~[7{C1  
 xYMNyj~  
GC3:ZpV`  
return n; ~YuRi#CTD:  
} FC= %_y  
9u'hC
i(  
g>[|/z P  
} >e4  
Xcq9*!%o  
SZ
9xj^"g  
/* 1m/=MET]  
**SiteInfoBean.java o3;u*f0rWn  
*/ GXEOgf#i  
package NetFox; i*9l  
oE&Zf/  
HA{-XPAWZ  
public class SiteInfoBean { HY]vaA`  
FjUp+5  
tVhY=X{N?  
private String sSiteURL; //Site's URL y*M
,&,$  
private String sFilePath; //Saved File's Path ta+'*@V+G  
private String sFileName; //Saved File's Name {-rK:*yP'u  
private int nSplitter; //Count of Splited Downloading File Po[u6K2&  
mI=^7'Mk  
`>fN?He  
public SiteInfoBean() @1#$  
{//nSplitter的缺省值为5 t|*PC  
//default value of nSplitter is 5 blZiz2F  
this("","","",5); S,5>g07-`  
} N(?yOB4gt  
GLb}_-|  
DA oOs}D  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y(:hN)  
{ ]xfAdBi  
sSiteURL= sURL; #R|M(Z">q  
sFilePath = sPath;
x5m .MQ J  
sFileName = sName; ?lb1K'(  
this.nSplitter = nSpiltter; Jkt L|u:k  
pBt/vSad  
#VC^><)3  
} oKTIoTb  
[pbX_  
?B %y)K  
public String getSSiteURL() =~Jv*c  
{ pFSVSSQRV|  
return sSiteURL; ',0~\V  
} 0$,Ag;"^?  
2 c'=^0:  
*&e+z-E  
public void setSSiteURL(String value) tGzYO/Zp  
{ UTUIL D  
sSiteURL = value; bF'~&<c  
} ~GfcI:Zz&  
3h"; 2  
W.\HfJ74  
public String getSFilePath() U:MkA(S%c  
{ 44?5]C7  
return sFilePath; N{/q p
 
} ckt^D/c2  
)1j~(C)E8  
ue/6DwUv  
public void setSFilePath(String value) T]EXm/  
{ SBjtg@:G0n  
sFilePath = value; *@G4i  
} /Fh"Gl^  
[ZURs3q  
7^KQQ([  
public String getSFileName() ]qXHalHY  
{ yL.si)h(p  
return sFileName; }#<Sq57n  
} nB,FJJ{kb  
>o 3X)  
"MC&!AMv  
public void setSFileName(String value) An[*Jx  
{ <$Uj ~jN  
sFileName = value; 4PD"[a="  
} ADv a@P  
>Fx$Rty  
/GM-#q a  
public int getNSplitter() OM!ES%c,  
{ gSR&CnqZ<  
return nSplitter; 
w,3`Xq@  
} _5U Fml9  
{K3\S 0L  
#yr19i ?  
public void setNSplitter(int nCount) GeHDc[7  
{ -&,NM  
nSplitter = nCount; d*A>P  
} h%=b"x  
} 6^{ hY^Z  
0M8JE9 Kx  
'12|:t&7  
/* N8D'<BUC  
**Utility.java &@+K%qW[e  
*/ "mPa>`?
 
package NetFox; RX2= iO"  
oSa FmP  
/mD KQ<  
public class Utility { Jh466; E  
m]"YR_  
TdQ^^{SRp  
public Utility() J1R%w{  
{ "apv)xdW  
oQyG  
IB!Wrnj?  
} }7.q[ ^oF  
c(Ha"tBJ  
//线程睡眠 =]zPUzr,|  
public static void sleep(int nSecond) cF(9[8c{  
{ A\#?rK  
try{ E?9_i :IX  
Thread.sleep(nSecond); q!ZmF1sU  
} ZcWl{e4  
catch(Exception e) 1|. 0]~0  
{ epG;=\f}m`  
e.printStackTrace (); w`7l;7[  
} RDqC$Gu  
} &9ZIf#R  
,@!d%rL:4]  
//日志 aZ0H)  
public static void log(String sMsg) %@xYg{  
{  C|lMXp\*  
System.err.println(sMsg); n9J>yud|  
} >{??/fBd-  
7J;.T%4l  
'~2v/[<`}  
public static void log(int sMsg) HkV/+ {;S~  
{ *ap#*}r!Nk  
System.err.println(sMsg); }>1E,3A:%G  
} $U0(%lIU  
} 0Gs]>B4r/  
#[xNE
C)  
$I/p6  
/* tV,zz;* Oe  
**TestMethod.java vOj$-A--qU  
*/ .F6#s  
package NetFox; wS^-o  
xD#/@E1'Y  
ri^yal<'  
public class TestMethod { <|_Ey)1 6  
G
`P+J  
0IdD  
public TestMethod() SeTU`WLEm  
{ ///xx/weblogic60b2_win.exe [5 V  
try{ Rq9gtx8,=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !INr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); HkN +:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w}i.$Qt  
fileFetch.start();
,]Ma,2  
} o MAK[$k;  
catch(Exception e){e.printStackTrace ();} h`Mf;'P  
?l(hS\N,  
xle29:?l  
} X ,  
A^7!+1*K+  
RW)C<g  
public static void main(String[] args) :+=*  
{ 72 6y
/o  
new TestMethod(); 21[F%,{.),  
} HHYcFoJwYN  
} ?xet:#R'  
点击下载更多相关资料