http断点续传简单实现（java)

/* `r&]Ydu:  
**SiteFileFetch.java h*\u0yD)  
*/ [-VIojs+u  
package NetFox; @jKB[S;JSn  
import java.io.*; _>4)q=  
import java.net.*; nNh5f]]  
^`bMFsP  
pz]!T'  
public class SiteFileFetch extends Thread { EvF[h:C2  
@iN"]GFjS  
+.QJZo_  
SiteInfoBean siteInfoBean = null; //文件信息Bean N{uVh;_  
long[] nStartPos; //开始位置 plM:7#eA  
long[] nEndPos; //结束位置 ,OFNV|S$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yV*4|EkvW  
long nFileLength; //文件长度 -0P9|;h5  
boolean bFirst = true; //是否第一次取文件 5&0qr$  
boolean bStop = false; //停止标志 .Gb!mG  
File tmpFile; //文件下载的临时信息 es<  
DataOutputStream output; //输出到文件的输出流 XfN(7d0  
^95njE`>t`  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
[gj>ey8T  
public SiteFileFetch(SiteInfoBean bean) throws IOException @]Lu"h#u=  
{ LX#gc.c  
siteInfoBean = bean; 1o?uf,H7O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;*WG9Y(W  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -! ^D8^s  
if(tmpFile.exists ()) z#2n+hwE  
{ |^"0bu"  
bFirst = false; `i<Z< <c>  
read_nPos(); zpZfsn!  
} PJ^qE|X  
else J|`.d46  
{ IRTD(7"oyp  
nStartPos = new long[bean.getNSplitter()]; wZWAx  
nEndPos = new long[bean.getNSplitter()]; pj7v{H+  
} 1:J+`mzpl  
IL`=r6\  
6w[EJ;=p_  
wOsg,p;\'  
} W:K'2j  
PlCj<b1D:  
gyuBmY  
public void run() jwP5pu  
{ 3cF8DNh  
//获得文件长度 /*MioaQB}p  
//分割文件 5G
GO:
  
//实例FileSplitterFetch 1x%B`d  
//启动FileSplitterFetch线程 7mE9Zo1  
//等待子线程返回 8{_lB#<[E  
try{ lSc=c-iOv  
if(bFirst) W6B"QbHYz  
{ gFsqCx<q  
nFileLength = getFileSize(); Eihn%Esa  
if(nFileLength == -1) KD?b|y@  
{ <T&v\DN  
System.err.println("File Length is not known!"); '.&Y)A6!  
} D}Sww5ZmP  
else if(nFileLength == -2) h`iOs>  
{ Hz)i.
AA 4  
System.err.println("File is not access!"); u08QE,
 
} QWtDZ>  
else (e0(GOqf4  
{ wxYGr`f  
for(int i=0;i<nStartPos.length;i++) ZB`d&!W>  
{ ck\W'Y*Q7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); iu3L9UfL[  
} +wf9!_'  
for(int i=0;i<nEndPos.length-1;i++) 5lM2nhlf'b  
{ Xj~%kPe  
nEndPos = nStartPos[i+1]; ~S\> F\v6'  
} ~H1<8py\J  
nEndPos[nEndPos.length-1] = nFileLength; 
_
W^;a  
} hCS}  
} mhy='AQJ  
9zY6hh**  
SZ}=~yoD(  
//启动子线程 k81%$E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ESYF4-d+  
for(int i=0;i<nStartPos.length;i++) V@[C=K
  
{ :2K@{~8r  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]qxl^Himq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Dp!91NgB p  
nStartPos,nEndPos,i); 2t PfIg  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {Ay dt8  
fileSplitterFetch.start(); ~9E_L?TW*  
} D~#%^a+Aq_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L#zD4L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9bspf {  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2TNK  
nEndPos = " + nFileLength); EC 1|$Co  
// fileSplitterFetch[nPos.length-1].start(); 6|~^P!&  
^39lUKL  
: ^("L,AF  
//等待子线程结束 M:b#">M  
//int count = 0; =4l @A>  
//是否结束while循环 *0to,$ n  
boolean breakWhile = false; i;-M8Q^  
v?Utz~lQ  
W"GW[~ h  
while(!bStop) eLnS1w2  
{ 1m#.f=u{R  
write_nPos(); P%gA`j  
Utility.sleep(500); EO~L.E%W  
breakWhile = true; kwL|gO1L  
7eju%d  
>7zC-3  
for(int i=0;i<nStartPos.length;i++) lo(
C3o'  
{ wjD<"p;P  
if(!fileSplitterFetch.bDownOver) +`_0tM1  
{ oQObr  
breakWhile = false; O9ps?{g  
break; 40pz<-B  
} D>-r `  
} -0x Q'1I  
if(breakWhile) x7U=1y(  
break; L!lmy&1  
P_w4 DU  
".N+nM~  
//count++;  ]%FAJ\  
//if(count>4) a4*976~![  
// siteStop(); p6
R+t]oH  
} mO;
QT  
I<ohh`.  
%^L{K[}  
System.err.println("文件下载结束！"); w.a9}GC  
} ,(pp+hNq  
catch(Exception e){e.printStackTrace ();} 3h d30o  
} 6#!CBY^{  
-(]CFnD_N  
f!`?_  
//获得文件长度 N)GHQlgH  
public long getFileSize() G(TFv\`vH  
{ b&mA1w[W]  
int nFileLength = -1; #Pp:H/b  
try{ Rd5_{F  
URL url = new URL(siteInfoBean.getSSiteURL()); 66,(yxg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fg3Jv*  
httpConnection.setRequestProperty("User-Agent","NetFox"); c|;n)as9(%  
.8u
@/f%pV  
#Uu,yHMv:;  
int responseCode=httpConnection.getResponseCode(); W>C?a=r~  
if(responseCode>=400) YnRO>`
  
{ "`V@?+3  
processErrorCode(responseCode); T7.Iqw3p  
return -2; //-2 represent access is error @$ Zh^+x!  
} Z17b=xJw  
BZ1wE1t  
Y~85Z0l  
String sHeader; gS5MoW1  
Y=O+d\_W  
rR-[CT  
for(int i=1;;i++) Q(nTL WW  
{ q.`<q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G rp{ .  
//Utility.log(in.readLine()); C2"^YRN,  
sHeader=httpConnection.getHeaderFieldKey(i); l|?tqCT ^h  
if(sHeader!=null) H3<tsK=:  
{ 8O9^g4?  
if(sHeader.equals("Content-Length")) +w^,!gA&  
{ R~kO5jpW  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?$ e]K/
*  
break; in<.0v9w  
} peO@ZKmM  
} EXCE^Vw  
else 95z|}16UK  
break; 1>j,v+  
} *k6
2Qz3  
} u,So+%  
catch(IOException e){e.printStackTrace ();} *VsVCUCz5*  
catch(Exception e){e.printStackTrace ();} RI&O@?+U  
P'lnS&yA  
FL^ _)`  
Utility.log(nFileLength); b;UBvwY_  
Fm0d0j  
$G9LaD#;M  
return nFileLength; AAlc %d/9  
} x2"1,1%H7  
rM,e$  
,s#~00C|  
//保存下载信息（文件指针位置） E5n7 <
 
private void write_nPos() $qQYxx@  
{ ]O"f%  
try{ 'NhQBk  
output = new DataOutputStream(new FileOutputStream(tmpFile)); E(4c&  
output.writeInt(nStartPos.length); P\7*ql`  
for(int i=0;i<nStartPos.length;i++) FT-.gi0  
{ )bOfs*S  
// output.writeLong(nPos); z/1
$G"  
output.writeLong(fileSplitterFetch.nStartPos); =#Sw.N  
output.writeLong(fileSplitterFetch.nEndPos); >,{sFc  
} Q^Cm3|ZO  
output.close(); 5p[}<I{  
} QPDh!A3T  
catch(IOException e){e.printStackTrace ();} FpRYffT 9u  
catch(Exception e){e.printStackTrace ();}  n?EgC8b9  
} #XDgvX >  
=#V^t$  
Z)`)9]*  
//读取保存的下载信息（文件指针位置） Kq3c Kp4  
private void read_nPos() xR0T'@q  
{ I/Vw2  
try{ iQgg[ )  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8@m$(I+  
int nCount = input.readInt(); `s CwgY+  
nStartPos = new long[nCount]; UPuoIfuqI  
nEndPos = new long[nCount]; 2F:qaz  
for(int i=0;i<nStartPos.length;i++) }8ubGMr,Y  
{ 7EE{*}?0E  
nStartPos = input.readLong(); 9;e!r DW,#  
nEndPos = input.readLong(); .C% 28fH  
} f$xXR$mjf  
input.close(); mQ:{>`  
} q
,,  
catch(IOException e){e.printStackTrace ();} ;|5-{+2U%  
catch(Exception e){e.printStackTrace ();} $9,&BW_*  
} p0@^1  
GEWjQ;g  
o6[.$C  
private void processErrorCode(int nErrorCode) )@N d3Z  
{ ZZT #V%Q=u  
System.err.println("Error Code : " + nErrorCode); ,0W^"f.g{m  
} ^HC6v;K  
6eV#x%z@v'  
En
M  
//停止文件下载
'E_~|C  
public void siteStop() ':vZ&  
{ QhZg{v[d  
bStop = true; vV}w>Ap[  
for(int i=0;i<nStartPos.length;i++) k8w\d+!v  
fileSplitterFetch.splitterStop(); 7=CkZ&(?  
pmNy=ZXx  
t WI-  
} rm[C{Pn  
} 7Z< ~{eD,  
//负责部分文件的抓取 FDz`U:8  
**FileSplitterFetch.java HT;^
u"a~  
*/ ljKIxSvCFp  
package NetFox; +X=*>^G(-  
Y,}_LS$f  
Jl/wP  
import java.io.*; WoEK #,I;  
import java.net.*; nq M7Is  
p~$c
wbQ!  
O(T5  
public class FileSplitterFetch extends Thread { $H)^o!  
4@PA+(kvS  
Xqf,_I=V  
String sURL; //File URL |THpkfW  
long nStartPos; //File Snippet Start Position yajdRU  
long nEndPos; //File Snippet End Position >pv.,cj  
int nThreadID; //Thread's ID BO[:=x`  
boolean bDownOver = false; //Downing is over |./mPV r  
boolean bStop = false; //Stop identical p%Z:SZZ  
FileAccessI fileAccessI = null; //File Access interface G4)~p!TSQ  
;g|Vt}a&4  
<Y]LY_(  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tk"+ u_uw  
{ sK}AS;:  
this.sURL = sURL; Fv$tl)p*  
this.nStartPos = nStart; gQn%RPMh  
this.nEndPos = nEnd; :$WO"HfMSn  
nThreadID = id; 'FErk~}/4s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 uR
0UfKK  
} b[74$W{  
T`&zQQ6F'  
rW{!8FhI  
public void run() 0pZvW  
{ 1R2IlUlzFr  
while(nStartPos < nEndPos && !bStop)  &9yZfp  
{ QUrPV[JQ  
y)G-6sZ/  
-> cL)  
try{ >P/36'  
URL url = new URL(sURL); k#].nQG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QZzamT)"  
httpConnection.setRequestProperty("User-Agent","NetFox"); _ \D%  
String sProperty = "bytes="+nStartPos+"-"; w*qj0:i5as  
httpConnection.setRequestProperty("RANGE",sProperty); g>lZs  
Utility.log(sProperty); ]S6Gz/4aV+  
?KC
(WaGJQ  
I#CS;Yh95  
InputStream input = httpConnection.getInputStream(); Lor__ K  
//logResponseHead(httpConnection); /.m}y$@GV  

`J
l_'P}  
MPJ0>Ly  
byte[] b = new byte[1024]; mp0!S  
int nRead; HK.Si]:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7+J<N@.d  
{ mP ^*nB@,  
nStartPos += fileAccessI.write(b,0,nRead); `)1qq @  
//if(nThreadID == 1) Dzw>[   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?D=%k8)Y  
} ?)"v~vs  
R #m1Aa  
FHZQyO<|  
Utility.log("Thread " + nThreadID + " is over!"); <Ow+LJWQK  
bDownOver = true; vg[zRWh8  
//nPos = fileAccessI.write (b,0,nRead); O u{|o0  
} j(Tk6S  
catch(Exception e){e.printStackTrace ();} ?h ym~,  
} +D#.u^  
} wafws*b%  
`>{S?t<  
yTU'voE.|  
//打印回应的头信息 SQf.R%cg$  
public void logResponseHead(HttpURLConnection con) 7, :l\t  
{ :N:e3$c  
for(int i=1;;i++) BKW%/y"  
{ S L~5[f  
String header=con.getHeaderFieldKey(i); Z4PAdT  
if(header!=null) kX'a*AG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); yI$MqR  
Utility.log(header+" : "+con.getHeaderField(header)); ~ePtK~,dv  
else O:[@?l  
break; \1#!%I=.  
} hKFB=U  
} m\J"P'=  
7e@Bkq0)  
Zq\ p%AU9  
public void splitterStop() LwEc*79  
{ )yv~wi  
bStop = true; >4AwjS}H  
} coc:$Sr%  
P,SI0$Z  
Kr;F4G|Qt  
} aW$))J)0  
)mRKIM}*W  
A-qpuI;f  
/* W:=CpbwENX  
**FileAccess.java 5lakP?  
*//文件访问(定位，写) &Zm1(k6&K  
package NetFox; /)xQ# yfX  
import java.io.*; 'lR
 f  
#'h(o/hz&&  
ZUeA&&{  
public class FileAccessI implements Serializable{ M%FKg/  
m}fY5r<<;/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F5f1j]c  
RandomAccessFile oSavedFile; AV["%$:  
long nPos; <=!|U0YV  
#Xd#Ncj  
=`BPGfCb  
public FileAccessI() throws IOException Ix|^c268o<  
{
pB0Do6+{  
this("",0); Qx !! Ttd{  
} 5[>N[}Ck>  
dZjh@yGP.  
 ,zrShliU  
public FileAccessI(String sName,long nPos) throws IOException KXga{]G:  
{ Zl`sY5{1  
oSavedFile = new RandomAccessFile(sName,"rw"); N`i`[ f  
this.nPos = nPos; %c,CfhEV%&  
oSavedFile.seek(nPos); 55|.MXzq  
} 7!E7XP6,~>  
U-:_4[
 
v@E/?\k"  
public synchronized int write(byte[] b,int nStart,int nLen) |oJ R+  
{ .FAuM~_99b  
int n = -1; 6dX l ny1H  
try{
{:d9q  
oSavedFile.write(b,nStart,nLen); o[CjRQY]P  
n = nLen; I~I$/j]e`  
} ]%/a'[  
catch(IOException e) ]$96#}7N  
{ z6Jfu:_N!  
e.printStackTrace (); (L6*#!Dt  
} AehkEN&H/t  
@](\cT64i3  
r<L>~S>yb  
return n; ='|H
UxFi  
} H)&pay  
Z8Il3b*)  
T~'9p`IW  
} vdN0YCXG  
wC[Bh^]  
hFWK^]~ a  
/* Lg
4I6 G  
**SiteInfoBean.java BHBMMjY5  
*/ *]_GFixi  
package NetFox; 4FgY!k  
`mTc  
r=ds'n"  
public class SiteInfoBean { w~(x*R}  
L]HYk}oD.  
tqo!WuZAj  
private String sSiteURL; //Site's URL Z'sO9Sg8>  
private String sFilePath; //Saved File's Path ?*8HZ1m#  
private String sFileName; //Saved File's Name 5Pl~du  
private int nSplitter; //Count of Splited Downloading File O6pL )6d  
n
ob^ I5?  
[,fdNxc8  
public SiteInfoBean() &$</|F)y  
{//nSplitter的缺省值为5 5U/1Z{  
//default value of nSplitter is 5 f~D> *<L4-  
this("","","",5); NTtRz(  
} <\cH9D`dE  
S*1Km&  
2x*C1   
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MO$dim>  
{ r?=7#/]  
sSiteURL= sURL; ly]n2RK  
sFilePath = sPath; ~|~j
01#  
sFileName = sName; 8oj-5|ct  
this.nSplitter = nSpiltter; '{:Yg3K  
k99ANW  
Uwqm?]  
} a/wkc*}}/  
\o j#*aL^  
xBC:%kG~#  
public String getSSiteURL() IlcFW  
{ rn?:ut
P  
return sSiteURL;  }[<eg>9#  
} VoJelyzh  
5PQs1B  
Y Hv85y  
public void setSSiteURL(String value) E*Q><UU  
{ zoV-@<Eh  
sSiteURL = value; L.xzI-I@D  
} SAEr$F^  
&n:F])`2  
SdfrLdi}Y  
public String getSFilePath() ]{[VTjC7rY  
{ Z<#beT6
 
return sFilePath; Vhww-A  
} O$%C(n(  
x6ig,N~AO  
\8!&XcA  
public void setSFilePath(String value) [lC*|4t&  
{ fodr1M4J  
sFilePath = value; f#p.=F$  
} >, &6zj  
#mX=Y>l
 
xe
: D7  
public String getSFileName() ;6} *0V_!k  
{ |j i}LWcD  
return sFileName; G'z&U?Ng  
} ?6 "F.\O@  
%
Iv0<oU  
URW'*\Xjb  
public void setSFileName(String value) .Wq`qF(;  
{ qu[x=LZ_  
sFileName = value; ,diV;d  
} e6f!6a+%  
i%W,Y8\uf*  
LTY@}o]\U  
public int getNSplitter() 1px:(8]{  
{ |400N +MK  
return nSplitter; T]nZ3EZ  
} 3X{=*wvt  
MQQ!@I`  
[PrR30:  
public void setNSplitter(int nCount) Kk~0jP_B9  
{ f#l/N%VoBZ  
nSplitter = nCount; 'sm+3d  
} VPf*>ph=  
}  IjDG  
~`{HWmah  
mLO{~ruu  
/* IrXC/?^h  
**Utility.java n\ma5"n0=\  
*/ F,e_`  
package NetFox; O;:8mm%(  
^
AD/N|X^  
VbtFM=Dg  
public class Utility { #cQ[ vE)y  
vbQo8GFp}  
(0"9562  
public Utility() #4''
Cs  
{ ]P ->xJ  
m\4jiR_o  
<9/oqp{C4  
} 7fl'nCo\"  
y-"*[5{W  
//线程睡眠 Gr#p QE2;  
public static void sleep(int nSecond) awXL}m[_!  
{ 9h$-:y3  
try{ ;P _`4w3  
Thread.sleep(nSecond); SM:{o&S`  
} D;<Qm,[  
catch(Exception e) _qmBPUx  
{ ~]A';xH&  
e.printStackTrace (); k-T_,1l{  
} \nx^=4*yk  
} Xt8;Pl  
C did*hxJ  
//日志 o)?"P;UhJX  
public static void log(String sMsg) q[q#cY:0  
{ KI$?0O  
System.err.println(sMsg); |zvxKIW;wd  
} y3$' gu|  
Vk$zA<sw"  
N:clwmo  
public static void log(int sMsg) KL0u:I(lWU  
{ @dJ
s  
System.err.println(sMsg); m5zP|s1`['  
} 89@89-_mC  
} 'oEFN
C9V  
GA6Z{U{XS  
r,MgIv(L  
/* iAT&C`,(&  
**TestMethod.java #0L:h?L  
*/ !HqIi@>8  
package NetFox; ,US~p_M!  
"~7| !9<  
*=S\jek  
public class TestMethod { 4^alAq^  
PKfxL}:"8  
=o_d2Ak  
public TestMethod() =YZp,{T  
{ ///xx/weblogic60b2_win.exe Sd^e!?bp  
try{ ,h5.Si>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Roy`HU ;0a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "a`0s_F,^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ui70|  
fileFetch.start(); BaiC;&(   
} -j]r\EVKS  
catch(Exception e){e.printStackTrace ();} `U!eh1*b  
ED"5y  
Y#{KGVT<  
} ',6QL4qV/  
 M5exo   
2v`VtV|B  
public static void main(String[] args) VuJth  
{ zG@9-s* L  
new TestMethod(); Ps<)?q6(  
} ,Xk8{=  
} 4m#i4  
点击下载更多相关资料