http断点续传简单实现（java)

/* ~@'wqGTp  
**SiteFileFetch.java OJe!K:  
*/ ]9YA~n\  
package NetFox; u> {aF{  
import java.io.*; :E")Zw&sW3  
import java.net.*; vkG#G]Qs";  
]+I9{%zB%8  
9lq5\ tL-  
public class SiteFileFetch extends Thread { h.Qk{v  
.z#eYn%d  
};'@'   
SiteInfoBean siteInfoBean = null; //文件信息Bean Biv)s@"f-Q  
long[] nStartPos; //开始位置 q1r
j!7  
long[] nEndPos; //结束位置 7i"b\{5  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %6Gg&Y$j!  
long nFileLength; //文件长度 _HwA%=>7  
boolean bFirst = true; //是否第一次取文件 38w^="-T  
boolean bStop = false; //停止标志 }d.X2?  
File tmpFile; //文件下载的临时信息 YoKE=ln7  
DataOutputStream output; //输出到文件的输出流 #L.,aTA<  
sa.H,<;  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） m"!SyN}&9?  
public SiteFileFetch(SiteInfoBean bean) throws IOException d|R-K7 ~~  
{ ?}Zo~]7E  
siteInfoBean = bean; f/Y&)#g>k  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [5&k{*}}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =`+D/ W\[Y  
if(tmpFile.exists ()) yr%[IX]R  
{ ?M:>2wl  
bFirst = false; i]MemM-  
read_nPos(); 9^/Y7Wp/@  
} a"@f< wU~  
else Z1fY' f  
{ ()aCE^C  
nStartPos = new long[bean.getNSplitter()]; GQ1/pys  
nEndPos = new long[bean.getNSplitter()]; t'2A)S  
} $#rkvG_w  
f\R_a/Us  
PMsb"=Ds  
/si<Fp)z  
} yEWm.;&3=  
}#7l-@{<  
^SpQtW118  
public void run() 1m5l((d  
{ Ey7zb#/<!  
//获得文件长度 WWpMuB_G  
//分割文件 ho=!Yy  
//实例FileSplitterFetch qt L]x -O  
//启动FileSplitterFetch线程 Vit-)o{zr  
//等待子线程返回 JU)^b V_  
try{ LuySa2,  
if(bFirst) z|Y54o3  
{ 1{N+B#*<[X  
nFileLength = getFileSize(); .2%t3ul[  
if(nFileLength == -1) 5 tKgm/  
{ i8?oe%9l  
System.err.println("File Length is not known!"); [!)
HWgx  
} ChK-L6  
else if(nFileLength == -2) "6d0j)YO  
{ 5Y+YN1  
System.err.println("File is not access!"); 3(oMASf  
} qWH
^/o  
else i(%2t(wf+  
{ K<^p~'f4P  
for(int i=0;i<nStartPos.length;i++) g>t1rZ  
{ a]p9[Nk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); VJ\qp%  
} +c%jOl  
for(int i=0;i<nEndPos.length-1;i++) uzHMQp  
{ o}Grb/LJ  
nEndPos = nStartPos[i+1]; 8y27O  
} 4w+AOWjd  
nEndPos[nEndPos.length-1] = nFileLength; qy'-'UlIr  
} K9zr]7;th  
} tMw65Xei6b  
4FzTf7h^  
Ue \A ,  
//启动子线程 Jt
O}i{A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \Vme\Ke*v)  
for(int i=0;i<nStartPos.length;i++) |tAkv  
{ P;.roD9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s4|tWfZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \:+\H0Bz  
nStartPos,nEndPos,i); :!_l@=l  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n#6{K6}k~  
fileSplitterFetch.start(); 2-@)'6"n  
} Z5xQ -T`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Tw';;euw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KKsVZ~<6u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^N^G?{EV/#  
nEndPos = " + nFileLength); MiZ<v/L2  
// fileSplitterFetch[nPos.length-1].start(); ow'G&<0b  
:6o%x0l  
g?80>-!bF  
//等待子线程结束 +(=-95qZ  
//int count = 0;
ZP~H!
 
//是否结束while循环 7RDmvWd-'?  
boolean breakWhile = false; H{n:R *  
CzG[S\{+  
jOT/|k  
while(!bStop) l)\Q~^cxd  
{ =Xvm#/  
write_nPos(); +d#8/S*  
Utility.sleep(500); +IS6l*_y>6  
breakWhile = true; ,Vq$>T@z  
vu)EB!%[  
'!A}.wF0  
for(int i=0;i<nStartPos.length;i++) Q
crhgR  
{ 'ge$}L}4  
if(!fileSplitterFetch.bDownOver) aB6/-T+u  
{ +\ftSm>  
breakWhile = false; s=:)!M.i  
break; -r,v3n  
} [s$x"Ex  
} J.R]) &CB  
if(breakWhile) 6/ 5c|  
break; 8XYxyOl  
"*HM8\  
LBq
2({="  
//count++; ftpPrtaP  
//if(count>4) a+HK fK  
// siteStop(); ~IYR&GEaUG  
} {XIpHr  
*` mxv0w~(  
kBqgz|jE%  
System.err.println("文件下载结束！"); Ye]K 74M.  
} b_`h2dUq  
catch(Exception e){e.printStackTrace ();} r^6@Zwox]  
} k.b=EX|  
9ye!kYF,  
LCSvw  
//获得文件长度 WyOav6/*K^  
public long getFileSize() 1n<4yfJ  
{ 8o+:|V~X  
int nFileLength = -1; 7HVENj_b+M  
try{ 8?8V; 
 
URL url = new URL(siteInfoBean.getSSiteURL()); <lR:^M[v5<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,y'6vW`%g9  
httpConnection.setRequestProperty("User-Agent","NetFox"); +EjXoW7V  
C)c*s C5N  
C&Qt*V#,  
int responseCode=httpConnection.getResponseCode(); i#4+l$q  
if(responseCode>=400) LpY{<:y  
{ ^~N:lW#=  
processErrorCode(responseCode); tm/>H  
return -2; //-2 represent access is error /RJ]MQ\*O  
} 3\4e{3$  
EC5= 2w<  

XY{N"S8  
String sHeader; e|:\Ps`8  
uDND o  
Ce-= -  
for(int i=1;;i++) -BP10-V  
{ Ms+ekY)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $1B?@~&  
//Utility.log(in.readLine()); 0R? @JC  
sHeader=httpConnection.getHeaderFieldKey(i); h!uyTgq  
if(sHeader!=null) EUs9BJFP  
{ :l"BNT[/  
if(sHeader.equals("Content-Length")) U"/T`f'H z  
{ "Y^j=?1k  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Zoxblk  
break; eCR
^$z=c  
} r+m.!+  
} =8#.=J[/  
else ,mx\ -lWFy  
break; |pS]zD  
} aV7VbC  
} 9[JUJ,#X'0  
catch(IOException e){e.printStackTrace ();} JwxKWVpWv  
catch(Exception e){e.printStackTrace ();} kJl^,q
 
2~\SUGW-  
a T(]  
Utility.log(nFileLength); QY4;qA  
&k,DAx`rN;  
X+sKG5nS  
return nFileLength; m5 sW68  
} ?;v\wx  
C_>XtcU  
oh:
9v+  
//保存下载信息（文件指针位置） ~tWh6-:|{J  
private void write_nPos() c_ncx|dUs  
{ xDU\mfeGj  
try{ a9;KS>~bq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OQfFS+6  
output.writeInt(nStartPos.length); x#3*C|A  
for(int i=0;i<nStartPos.length;i++) u; KM[FmK  
{ LDEc}XXb  
// output.writeLong(nPos); O>+=cg  
output.writeLong(fileSplitterFetch.nStartPos); UFT JobU  
output.writeLong(fileSplitterFetch.nEndPos); p~3
x=X4  
} awo'#Y2>  
output.close(); *<S>PbqLw  
} sgi5dQ  
catch(IOException e){e.printStackTrace ();} nK03xYA  
catch(Exception e){e.printStackTrace ();} smfI+Z S"  
} D|Q7dI
Zm  
(_4DZMf  
L!*+:L DL  
//读取保存的下载信息（文件指针位置） ?Xvy0/s5  
private void read_nPos() #S9J9k  
{ {|>Wwa2e  
try{ [m{sl(Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %m dtVQ@  
int nCount = input.readInt(); J;Z2<x/H  
nStartPos = new long[nCount]; O<Q8%Az  
nEndPos = new long[nCount]; &kzys
v-_  
for(int i=0;i<nStartPos.length;i++) M1WD^?tKQ.  
{ z]rr Q=dAA  
nStartPos = input.readLong(); .B<Bqr@?8  
nEndPos = input.readLong(); +@^);b6  
} l3p :}A  
input.close(); 3s?u05_  
} NW5OLa")J<  
catch(IOException e){e.printStackTrace ();} Q;VuoHj!  
catch(Exception e){e.printStackTrace ();} 6 /YJA*  
} Le?g,c  
>Y8\f:KQ  
(eU4{X7  
private void processErrorCode(int nErrorCode) xE@/8
h  
{ P#!
N  
System.err.println("Error Code : " + nErrorCode); gZ^Qt.6Z  
} QPB,B>Z  
u#EcR}=]  
XEA5A.uc  
//停止文件下载 ^D+^~>f  
public void siteStop() B%uY/Mwz$  
{ k*)sz  
bStop = true; 9\hI:rI  
for(int i=0;i<nStartPos.length;i++) w -o#=R_  
fileSplitterFetch.splitterStop(); F^bY]\-5  
{*B0lr`  
C^LxuUW  
} wjl)yo$z  
} Q*T'tkp  
//负责部分文件的抓取 ,\v'%,:C  
**FileSplitterFetch.java D {Ol8:  
*/ l[:Aq&[o3  
package NetFox; >-N(o2j3  
M{5AQzvs  
R]X 0D.  
import java.io.*; vb]kh_  
import java.net.*; uEJ8Lmi
 
3<W
%z]k@M  
:6lvX$  
public class FileSplitterFetch extends Thread {  i
iQn/%  
!5lV#w!vb  
an"~n`g  
String sURL; //File URL J?3/L&seA  
long nStartPos; //File Snippet Start Position )pHlWi|h  
long nEndPos; //File Snippet End Position 7?R600OA  
int nThreadID; //Thread's ID dWQs
C|  
boolean bDownOver = false; //Downing is over u|t l@_  
boolean bStop = false; //Stop identical 8-x-?7  
FileAccessI fileAccessI = null; //File Access interface 1V1I[CxlX  
70 7( LG  
op9dYjG7  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _|GbU1Hz  
{ [-$ Do  
this.sURL = sURL; ]S&ki
}i&  
this.nStartPos = nStart; 5_'lu  
this.nEndPos = nEnd; &;-zy%#l  
nThreadID = id; U)bv,{-q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <v0`r2^S{-  
} RX>P-vp  
0uDDaFS  
IANSpWea?  
public void run() o0C&ol_  
{ 1]G)41  
while(nStartPos < nEndPos && !bStop) ~I5hV}ZT  
{ ~
)y
s,Q  
RN(I}]]a  
&kIeW;X  
try{ 0mSP  
URL url = new URL(sURL); Gf\h7)T\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A!bG2{r  
httpConnection.setRequestProperty("User-Agent","NetFox"); p5#x7*xR6  
String sProperty = "bytes="+nStartPos+"-"; 0h@FHw2d  
httpConnection.setRequestProperty("RANGE",sProperty); 7tcadXk0  
Utility.log(sProperty); k B>F(^  
G@H!D[wd  
"9s_[e  
InputStream input = httpConnection.getInputStream(); V_SH90@)+  
//logResponseHead(httpConnection); f zo'9  
h) Wp  
(*$b
TI/~  
byte[] b = new byte[1024]; jCJcVO>OZ  
int nRead; DRQx5fgL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Gc|)4c  
{ mtv8Bm=<  
nStartPos += fileAccessI.write(b,0,nRead); kCTf>sJe  
//if(nThreadID == 1) tNTSy
=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YGyv)\  
} d5m-f/  
k|)fl l  
tz@MZs09  
Utility.log("Thread " + nThreadID + " is over!"); 1.!U{>$  
bDownOver = true; }9S}?R  
//nPos = fileAccessI.write (b,0,nRead); R(~wSL*R>  
} H\S)a FY[  
catch(Exception e){e.printStackTrace ();} U7s$';y"%  
} O{X~,Em=q  
} W r/-{Wt  
Tzex\]fw  
-)}s{[]d6m  
//打印回应的头信息 sE"s!s/  
public void logResponseHead(HttpURLConnection con) :k/Xt$`  
{ 2 kDsIEA  
for(int i=1;;i++) `}PYltW  
{ 6$r\p2pi0  
String header=con.getHeaderFieldKey(i); )]1hN;Nz  
if(header!=null) 6CBk=)qH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); dDPQDIx  
Utility.log(header+" : "+con.getHeaderField(header)); +& r!%j7  
else OjUPvR2 0  
break; `
t U  
} Z4VFfGCTL  
} F^O83[S  
~29p|X<  
!&VfOx:PN  
public void splitterStop() 8?+|4:#=*J  
{ ]Btkoad  
bStop = true; *HKw;I   
} >aVgI<   
B?VTIq>  
7QsD"rL  
} @gI1:-chB  
fM;,9  
;/K2h_=3z  
/* zU?O)w1'  
**FileAccess.java 7PY$=L48A  
*//文件访问(定位，写) 2zTi/&K&  
package NetFox; <sH}X$/  
import java.io.*; !$Nj!  
#V!a<w4_  
dVQ[@u1,  
public class FileAccessI implements Serializable{ <gp?}Lk  
I_J&>}V'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [*',pG  
RandomAccessFile oSavedFile; s6bsV
AO>  
long nPos; bHwEd%f  
I^?tF'E  

kU<t~+  
public FileAccessI() throws IOException l[}4 X/  
{ c2npma]DZ  
this("",0); tq3_az ~1  
} y}odTeq  
C ^Y\?2h1  
8-2`S*  
public FileAccessI(String sName,long nPos) throws IOException 4_R|3L  
{  $GJT  
oSavedFile = new RandomAccessFile(sName,"rw"); x|6]+?l@6  
this.nPos = nPos; -R`{]7V  
oSavedFile.seek(nPos); YFO{i-*q  
} %nZ
l`<M  
Z?axrGmg0  
hS]w A"\87  
public synchronized int write(byte[] b,int nStart,int nLen) vi,hWz8WB  
{ Y?0/f[Ax,y  
int n = -1; $coO~qvU  
try{ 1 R5pf  
oSavedFile.write(b,nStart,nLen); ZwmucY%3  
n = nLen; -#|D>  
} qA)OkR'm  
catch(IOException e) kka5=u  
{ ;5Sdx5`_  
e.printStackTrace (); un{ZysmtB6  
} m@4Dz|  
$]2)r[eA)  
6}4})B2  
return n; `AJ[g>py^|  
} b^1QyX^?:  
eVXXn)>  
F-yY(b]$  
} ^#/FkEt7bp  
3nxG>D7  
v4P"|vZ$&  
/* #.Rn6|V/4  
**SiteInfoBean.java f9De!"*&  
*/ l:85 _E  
package NetFox; /(N/DMl[  
isQ(O  
t[^$F,  
public class SiteInfoBean { ~3&{`9Y  
*3GV9'-P  
~4~`bT9  
private String sSiteURL; //Site's URL yYG<tUG;  
private String sFilePath; //Saved File's Path Jup)m/  
private String sFileName; //Saved File's Name =
6%oW2E\  
private int nSplitter; //Count of Splited Downloading File f[^f/jGm  
AU{"G  
fr@F7s5}  
public SiteInfoBean() 9njwAKF?  
{//nSplitter的缺省值为5 !gsvF\XDM  
//default value of nSplitter is 5 H];B?G';C  
this("","","",5); rd%%NnT"  
} *IG$"nu  
5(1:^:LGK  
-3I3 X  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $NXP)Lic)  
{ wKV4-uyr  
sSiteURL= sURL; #+I'V\[  
sFilePath = sPath; .Ea
o|;  
sFileName = sName; \CbJU  
this.nSplitter = nSpiltter; UtZ,q!sg  
j)A#}4jd  
{1W:@6tl  
} ccD+AGM.  
g)D_!iz  
Fnw:alWr  
public String getSSiteURL() Ha'[uEDb  
{ yIMqQSt79z  
return sSiteURL; .HqFdsm  
} WjV15\,  
dUI5,3*  
'D\Q$q  
public void setSSiteURL(String value) )Fw/Cu  
{ _X6'uJ  
sSiteURL = value; x(_[D08/TT  
} K=g</@L6R  
t}EMX9SQ  
qe~x?FO_>  
public String getSFilePath() je4l3Hl  
{ bDI%}k9#  
return sFilePath;  6@S6E(^  
} :2 ;Jo^6Se  
okNo-\Dh!  
G0cG%sIl  
public void setSFilePath(String value) TkbaoD  
{ I[\~pi,  
sFilePath = value; NFK
`,  
} eI #Gx_mg  
APQq F/  
=OVDJ0ozZ  
public String getSFileName() G#M)5'Q]U  
{ g?C;b>4  
return sFileName; bF)G+IH  
} !3ggQG!e  
hsZ/Vnn`  
H}@:Br
i  
public void setSFileName(String value) k;WD[SV  
{ /?\3%<vn  
sFileName = value; hlTbCl  
} 2z.ot'  
92+8z
X  
c\bL_  
public int getNSplitter() Ucj?$=  
{ ZykMri3bi  
return nSplitter; nQ%HtXt;  
} vW63j't_  
" \$^j#o  
}[*'  
public void setNSplitter(int nCount) <=uYfi3,  
{ D28`?B9(  
nSplitter = nCount; 8a)AuAi?!  
} Ic&h8vSU  
} q2GW3t  
D7Q+w  
*Ak.KBg  
/*  ao(T81  
**Utility.java ON?Y Df  
*/ ;"3B,Yj  
package NetFox; jYsAL=oh,*  
c/{FDN  
}`"`VLh  
public class Utility { 1^iBS  
8HF^^Cva  
xU *:a[g
 
public Utility() L'e_?`!:  
{ 8fR(y~_gF  
K*6"c.D  
So:X!ljN(e  
} >}5?`.K~Q*  
X/!_>@`7?  
//线程睡眠 xad`-vw  
public static void sleep(int nSecond) yPyu)  
{ NnZW@l
n"|  
try{ t [QD#;  
Thread.sleep(nSecond); @Mk`Tl  
} >r.]a`  
catch(Exception e) YJi%vQ*]  
{ 8h)XULs2  
e.printStackTrace (); MvVpp;bd  
} AeJ

;g  
} voWH.[n^_  
1MelHW  
//日志 UHBXq;?&q  
public static void log(String sMsg) K^-1M?  
{ w~'xZ?  
System.err.println(sMsg); f|RmAP;X,  
} *Cy54Z#  
+A9~h/"kt  
$ /VQsb  
public static void log(int sMsg)  %Bq~b$  
{ UA[`{rf  
System.err.println(sMsg); DM.lQ0xk  
} r8k(L{W  
} $KHm5*;nd  
kmB!NxF>)F  
p [O6  
/* !iXRt")  
**TestMethod.java \1EuHQ?  
*/ b*|~F  
package NetFox; =Q#I@SVp2$  
Z%T Ajm  
SnCwoxK  
public class TestMethod { :=QX^*  
qHtQ4_Zn;  
Uj@th  
public TestMethod() ?u|??z%  
{ ///xx/weblogic60b2_win.exe 7WJ\nK  
try{ j0=6B  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {>&~kM@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'r;mm^cS?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O"m7r ds  
fileFetch.start(); wjarQog5Y  
} =u~nLL  
catch(Exception e){e.printStackTrace ();} Lx"GBEkt7  
q*!R4yE;C  
'H1~Zhv  
} `y8pwWo-o  
MqmQ52HR  
Z~'t'.=z  
public static void main(String[] args) t;O)  
{  tm1=  
new TestMethod(); 0.GFg${v`  
} z2=bbm:  
} V>6klA}o
 
点击下载更多相关资料