http断点续传简单实现（java)

/* $H*/;`,\[  
**SiteFileFetch.java U[||~FW'  
*/ p^X^1X7  
package NetFox; pP.'wSj  
import java.io.*; DW2>&|  
import java.net.*; 4v.d-^  
3 ^}A %-bS  
fx?$9(r,  
public class SiteFileFetch extends Thread { (bm;*2  
u"+}I,'L  
m5-9yQ=.  
SiteInfoBean siteInfoBean = null; //文件信息Bean ]gP5f@`  
long[] nStartPos; //开始位置 J^zi2jtV  
long[] nEndPos; //结束位置 2{oThef[O  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 tT5pggml  
long nFileLength; //文件长度 I}.i@d'O  
boolean bFirst = true; //是否第一次取文件 S; /. %
 
boolean bStop = false; //停止标志 d3^7ag%  
File tmpFile; //文件下载的临时信息 aj8Rb&  
DataOutputStream output; //输出到文件的输出流 wNDbHR  
Ly #_?\bn  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） AsxD}Nw[Z*  
public SiteFileFetch(SiteInfoBean bean) throws IOException o8S"&O ?  
{ ctn, ]ld  
siteInfoBean = bean; /QxlGfNZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); r88"#C6E'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .C!vr@@]  
if(tmpFile.exists ()) f j<H6|3  
{ VmvQvQ/9R  
bFirst = false; bToq$%sCg  
read_nPos(); wCb(>
pL0  
} f[jNwb  
else 658^"]Rk'/  
{ {eHAg<+  
nStartPos = new long[bean.getNSplitter()]; @x{`\AM|%  
nEndPos = new long[bean.getNSplitter()]; dULS^i@@  
} q|dH~BK  
.<&s%{EW  
reiU%C  
-x]`DQUg  
} yoS? s  
K*vU5S  
$8=@R'  
public void run() erFv(eaDK  
{ `f`TS#V  
//获得文件长度 P:{<*`q  
//分割文件 ]?<n#=eW  
//实例FileSplitterFetch Y83GKh,*  
//启动FileSplitterFetch线程
s&tE_  
//等待子线程返回 qVgd(?hJ#  
try{ #kcSQ'  
if(bFirst) >k(MUmhX  
{ WUoOGbA `  
nFileLength = getFileSize(); &M[f&_"8Q  
if(nFileLength == -1) WES#ZYtT  
{ :qj<p3w~}  
System.err.println("File Length is not known!"); q,l)I+  
} <~"lie1  
else if(nFileLength == -2) 
sC7/9</  
{ +4)7j&L  
System.err.println("File is not access!"); Hf
c"L>  
} %&+59vq   
else SW 8x]B  
{ P3o@gkXP  
for(int i=0;i<nStartPos.length;i++) {"}V&X160o  
{ Sycw %k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m $dV<  
} !m
y8AWO'  
for(int i=0;i<nEndPos.length-1;i++) elO<a]hX  
{ M\2"gT-LV  
nEndPos = nStartPos[i+1]; WxUxc75  
} %dttE)oH?  
nEndPos[nEndPos.length-1] = nFileLength; 77,oPLSn  
} FxW&8 9G  
} B$a-og(  
wWjG JvJ  
m7jA ,~O  
//启动子线程 o
y\B;aAK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @wN G  
for(int i=0;i<nStartPos.length;i++) o(G"k  
{ xvm5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R.RSQk7;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]k%PG-9  
nStartPos,nEndPos,i); dl|gG9u4Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P~ 0Jg# V  
fileSplitterFetch.start(); HSz" tN  
} 7{M>!} rY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z S|WnMH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); SaDA`JmO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3YL l;TP_  
nEndPos = " + nFileLength); *dsX#Iz  
// fileSplitterFetch[nPos.length-1].start(); 1y5Ex:JVZT  
~(X(&  
Af-UScD%G  
//等待子线程结束 ;)hw%Z]Jj$  
//int count = 0; S\ ,mR4:  
//是否结束while循环 4_=Ja2v8;`  
boolean breakWhile = false; !]koSw}  
@F5f"8!.\  
<nHkg<O6Y  
while(!bStop) t#wmAOW  
{ yI;"9G  
write_nPos(); "VUY
h$=[  
Utility.sleep(500); 5LW}h^N  
breakWhile = true; ! fl4"  
6(V /yn~  
IApT'QNM  
for(int i=0;i<nStartPos.length;i++) >,5i60Q  
{ [ !%R#+o=F  
if(!fileSplitterFetch.bDownOver) u'5`[U -!  
{ 2Aq~D@,9=:  
breakWhile = false; }VCI=?-  
break; ?UZ?NY
  
} 6[ga$nF?  
} 963aW*r  
if(breakWhile) DVp5hR_$  
break; `C72sA{M.  
(/{aJV  
z~oDWANP  
//count++; 4gBp8*2  
//if(count>4) 4ne5=YY*  
// siteStop(); 9<1F[SS<s9  
} TJ_=1Y@z  
|Ul,6K@f"5  
vT{kL  
System.err.println("文件下载结束！"); R)8s  
} </~ 6f(mg  
catch(Exception e){e.printStackTrace ();} c0- ;VZ'  
} d IB }_L  
gX @`X  
MDa7 B +4  
//获得文件长度 Hh[Tw&J4  
public long getFileSize() ]!"S+gT*C  
{ =t0tK}Y+4  
int nFileLength = -1; 1T|$BK@)  
try{ 4`v!Z#e/aX  
URL url = new URL(siteInfoBean.getSSiteURL()); JgfVRqm   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &)9{HRP  
httpConnection.setRequestProperty("User-Agent","NetFox"); hlbvt-C?}"  
3{7T4p.G  
TpfZ>d2  
int responseCode=httpConnection.getResponseCode(); Ty4S~ClO#'  
if(responseCode>=400) 5]Da{Wmgs  
{ .IrNa>J
~  
processErrorCode(responseCode); :z"!kzdJ  
return -2; //-2 represent access is error #?O&  
} #
J\rv'  
*|:Q%xr-  
7L(eh7  
String sHeader; eny/ fm  
Ve3 ;  
B;#J"6w  
for(int i=1;;i++) @4+#Xd7"  
{ ~Qj}ijWD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y}G_Z#-!  
//Utility.log(in.readLine()); ~f>2U]F>5  
sHeader=httpConnection.getHeaderFieldKey(i); -yH,5vD  
if(sHeader!=null) UXr5aZ7y  
{ S6i@"h5  
if(sHeader.equals("Content-Length")) 8F5|EpB9M  
{ 'xK.UI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); UmU:j@xvg  
break; @E9" Zv-$  
} PO-"M)M  
} Tbbz'b;{  
else .8gl< vX  
break; f i~I@KJ>  
} ]wn/BG)  
} /8ynvhF#  
catch(IOException e){e.printStackTrace ();} dbdM"z4  
catch(Exception e){e.printStackTrace ();} $hrIO+  
cWAtju?L;  
P87# CAN  
Utility.log(nFileLength); )q~DT
R^z-  
<E,%@  
r|<DqTc6l  
return nFileLength; u_O# @eOc  
} TV59(bG.2  
s<QkDERMX  
w|Cx>8P8@  
//保存下载信息（文件指针位置） "?}uQ5f  
private void write_nPos() _ Y2 U7W  
{ kQ>^->w  
try{ AC%JC+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); MHj,<|8Q  
output.writeInt(nStartPos.length); |pZUlQ
bb  
for(int i=0;i<nStartPos.length;i++) Td\o9
 
{ O'*@ Ytn  
// output.writeLong(nPos); afEF]i  
output.writeLong(fileSplitterFetch.nStartPos); L{{CAB!  
output.writeLong(fileSplitterFetch.nEndPos); PgM(l3x  
} 1eS_ nLFw~  
output.close(); n]Li->1  
} :\ QUs}  
catch(IOException e){e.printStackTrace ();} ?*"srE,#JX  
catch(Exception e){e.printStackTrace ();} 4$6T+i2E   
} is^pgKX  
i{c@S:&@^  
95W?{> @  
//读取保存的下载信息（文件指针位置） h11.'Eej`  
private void read_nPos() 8P' ana  
{ e( X|3h|  
try{ LaMLv<)k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  UL@9W6  
int nCount = input.readInt(); s,]%dG!  
nStartPos = new long[nCount]; v;1F[?@3Y  
nEndPos = new long[nCount]; n'FwM\  
for(int i=0;i<nStartPos.length;i++) U/{6%
Qy  
{ Zi\['2CG  
nStartPos = input.readLong(); W-~n|PX8+  
nEndPos = input.readLong(); c:!zO\P#  
} /'
.=sH  
input.close(); :nY
2O  
} XMN:]!1J  
catch(IOException e){e.printStackTrace ();} "Dcs])7Q  
catch(Exception e){e.printStackTrace ();} e$)300 o  
} 6X2PYJJZ  
2.e vx  
Y5q3T`xE  
private void processErrorCode(int nErrorCode) SGc8^%-`  
{ Y.#:HRtg
W  
System.err.println("Error Code : " + nErrorCode); p,g1eb|E  
} ^L4Qbc(vJ  
~X(UcZ2  
,"0)6=AE  
//停止文件下载 y@V_g'  
public void siteStop() siD
h="{s  
{ 13'vH]S$M  
bStop = true; 3riw1
r;Q  
for(int i=0;i<nStartPos.length;i++) UYP9c}_,4  
fileSplitterFetch.splitterStop(); I751t  
9Z"+?bv/  
"6ECgyD+E!  
} `Mj}md;O"  
} #V02
hs1  
//负责部分文件的抓取 d%@~mcH>  
**FileSplitterFetch.java 1nknSw#  
*/ {:nQl}  
package NetFox; HmmS(fU  
g9fq5E<G  
`Hx
~UH)  
import java.io.*; ,B}I?vN.  
import java.net.*; t>)45<PEw  
qSCv )S(  
:wqC8&V  
public class FileSplitterFetch extends Thread { F|bYWYED;  
ikBYd }5  
v
a|*c22;|  
String sURL; //File URL Q?t^@  
long nStartPos; //File Snippet Start Position 2I1uX&g  
long nEndPos; //File Snippet End Position F1%vtk;2?  
int nThreadID; //Thread's ID P>Euq'ajX  
boolean bDownOver = false; //Downing is over DaHZ{T8>d  
boolean bStop = false; //Stop identical Pl=]Srw  
FileAccessI fileAccessI = null; //File Access interface c?2MBtnu  
j9+I0>#X  
4M&`$Wim  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :K82sCy%5  
{ ^i)hm  
this.sURL = sURL; ''OfS D_g  
this.nStartPos = nStart; U).*q?.z  
this.nEndPos = nEnd; $*a'84-5G-  
nThreadID = id; rx"s!y{!-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 iZ3W"Vd`b  
}  ,B<l  
nz1'?_5  
)+")Sz3zx  
public void run() -m= 8&B  
{ m9}AG Rj  
while(nStartPos < nEndPos && !bStop) ]j~"m
FAP  
{ GV6K/T:  
'V+
dBt3  
B\*@krI@  
try{ I:V0Xxz5t  
URL url = new URL(sURL); ]&~]#vB#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {4aWR><  
httpConnection.setRequestProperty("User-Agent","NetFox");  }}<Z,/O  
String sProperty = "bytes="+nStartPos+"-"; BE
lJB&I  
httpConnection.setRequestProperty("RANGE",sProperty); Il@Y|hK  
Utility.log(sProperty); z\ss4  
q}BzyC=:n  
}{9&:!uA  
InputStream input = httpConnection.getInputStream(); ^0
4Q%,  
//logResponseHead(httpConnection); tcr//  
5Ky#GuC  
2O"P
2(1}v  
byte[] b = new byte[1024]; gkBdR +  
int nRead;

CRve.e8J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4n1; Bh$  
{ 7`IpBm<  
nStartPos += fileAccessI.write(b,0,nRead); yV3^Qtb!  
//if(nThreadID == 1) ZD#9&q'4<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \AUI|M;'  
} =$8nUX`  
0Z<I%<8bK  
wv QMnE8\  
Utility.log("Thread " + nThreadID + " is over!"); y %$O-q  
bDownOver = true; e^YHJ>@  
//nPos = fileAccessI.write (b,0,nRead); X2mREt9  
} -7uwOr  
catch(Exception e){e.printStackTrace ();} [OTJVpC  
} wfvU0]wk}  
} lDC$F N  
R`";Z$~{  
)Dp/('Z2  
//打印回应的头信息 LLWB
  
public void logResponseHead(HttpURLConnection con) AB Xl  
{ _{vkX<s  
for(int i=1;;i++) `dMqe\o
%!  
{ F
["wDO  
String header=con.getHeaderFieldKey(i); SjjI
r ^  
if(header!=null) *{undZ?(>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `u!l3VZ/4  
Utility.log(header+" : "+con.getHeaderField(header)); , $Qo =  
else MaBYk?TR~  
break; vkS)E0s  
} /:6Wzj  
} C.^Ven  
"
!>DX1rsi  
]u-]'P  
public void splitterStop() I]Tsz'T!9  
{ 5 )2:stT73  
bStop = true; MF60-VE  
} _mS!X
F~`P  
0U/K7sZ  
c(co\A.]:6  
} FEPXuCb  
Glq8
5S  
]nQt>R p_  
/* r!P}u  
**FileAccess.java 2>-S-;i  
*//文件访问(定位，写) o47r<>t  
package NetFox; RO0>I8c1c  
import java.io.*; 3Y)PU=  
{Y}dv`G#Iu  
+5.t. d  
public class FileAccessI implements Serializable{ MRr</o  
\ 6EKgC1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LAx4Xp/  
RandomAccessFile oSavedFile; 1iL'V-y  
long nPos; 0w'j+  
Et"?8\"n7  
T&T/C@z'R  
public FileAccessI() throws IOException 58%'UwKn  
{ ?6c-7QV  
this("",0); j7FN\ cz  
} .0u/|Yx  
7@.cOB`y@3  
S1_6C:^k  
public FileAccessI(String sName,long nPos) throws IOException qj01]  
{ '`Bm'Dd  
oSavedFile = new RandomAccessFile(sName,"rw"); :[@k<8<]  
this.nPos = nPos; %8a
C1x  
oSavedFile.seek(nPos); ,:Vm6u!  
} :RSz4   

EA.D}XC  
M,j(=hRJ/E  
public synchronized int write(byte[] b,int nStart,int nLen) zPEg  
{ e&ANp0|W  
int n = -1; RUCPV[{b  
try{ (F7_S*  
oSavedFile.write(b,nStart,nLen); iFSJL,QZ3  
n = nLen; D2YZ9e
  
} Sz{O2lY  
catch(IOException e) 41#w|L \  
{ %or,{mmiM:  
e.printStackTrace (); .%'(9E  
} ES<1tG  
GN#<yv$av  
`"iY*  
return n; Q@e[5RA+]  
} Mcw4!{l`  
n[Zz]IO,g  
IYWjHE+)d  
}
1\RGM<q$f  
MyJ4><oG  
JB</euyV  
/* BY\:dx)mK  
**SiteInfoBean.java =k}SD96  
*/ !>x|7   
package NetFox; -Z4{;I[Q@  
+u@aJ_^
 
X.O
Na_  
public class SiteInfoBean { 2c<&eX8"  
$=sXAK9   
IUGz =%[  
private String sSiteURL; //Site's URL A>VI{  
private String sFilePath; //Saved File's Path ?6Cz[5\  
private String sFileName; //Saved File's Name rdJm{<  
private int nSplitter; //Count of Splited Downloading File |5I'CNi\  
xy+QbDT  
W$dn_9W  
public SiteInfoBean() v]2S`ffP  
{//nSplitter的缺省值为5 q,<[hBri-  
//default value of nSplitter is 5 O#nR>1h  
this("","","",5); _ 7oV<  
} k<w(i k1bi  
89{HJ9}  
=U OLT>!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @vgG1w  
{ uBg 8h{>  
sSiteURL= sURL; /)N@M  
sFilePath = sPath; ?!w^`D0}o  
sFileName = sName; 6nDV1O5  
this.nSplitter = nSpiltter; L+B?~_*  
OYM@szM  
pDPxl?
S  
} 7Y=cn_ wU  
d {lP  
g}&hl"j  
public String getSSiteURL() n?#!VN3  
{ Z>F^C}
8f  
return sSiteURL; C7T(+Wd!,  
} @J[6,$UVu  
I3u{zHVwI  
M|T4~Q U&  
public void setSSiteURL(String value) "_L?2ta  
{ #LcrI  
sSiteURL = value; DG(7|`(aY  
} +y[@T6_  
q<e&0u4  
Vi!Q  
public String getSFilePath() Xog/O i  
{ )g| BMmB  
return sFilePath; 8B!aO/Km  
} :/YO ni1h  
Jn
D{J`:  
&a> lWE  
public void setSFilePath(String value) y$Zj?Dd#  
{ >1L=,M  
sFilePath = value;
PZ:u_*Vu`  
} I^*'.z!4Q  
1`f_P$&Z_J  
3HG;!D~m;  
public String getSFileName() L^kp8
o^$  
{ 2J;`m_oP  
return sFileName; Kj=gm .  
} WV;=@v  
P#kGX(G9!  
D|I Ec?  
public void setSFileName(String value) :(3|HTz  
{ NX* O_/  
sFileName = value; ir>]r<Zl  
} 5FvOznK^e  
FHy76^h>e  
pvWau1ArNq  
public int getNSplitter() Hyk'c't_O  
{ 5G}6;UY  
return nSplitter; >Dm8m[76  
} ?9j{V7h  
&'|B =7  
h4&;?T S  
public void setNSplitter(int nCount) ;'T{
li2  
{ v|Jlf$>  
nSplitter = nCount; hSqY$P  
} &Y|Xd4:  
} Rz%e>)  
@}FAwv^f  
L/}iy}  
/* xIbMs4'iEx  
**Utility.java k@!r#`j3  
*/ 4
YG/`P  
package NetFox; KHiFJ_3  
\jW)Xy  
KM?1/KZ/~  
public class Utility { 9G?ldp8  
V+MK'<#B  
t *6loS0+  
public Utility() db=$zIB[:  
{ qG8s;_G  
r >{G`de4  
0V,Nv9!S  
} )yee2(S  
Y,z??bm~J  
//线程睡眠 u.|~   
public static void sleep(int nSecond) C.a5RF0  
{ TT!ET<ciN  
try{ Hy
;Hs#  
Thread.sleep(nSecond);
Y8s;w!/  
}  {E9v`u\  
catch(Exception e) ~9pM%N V  
{ l?N`{,1^  
e.printStackTrace (); >.9eBz@  
} _v5t<_^N  
} sOFa!bdPW  
JXQPT  
//日志 }amU[U,  
public static void log(String sMsg) ;|ub!z9GG  
{ >G)qns9  
System.err.println(sMsg); dT@UK^\  
} 4z4v\IpB  
o.:p_(|hI  
~GB=Nz  
public static void log(int sMsg) ^i%A7pg  
{ ~2}Pl)  
System.err.println(sMsg); 3*S[eqMJc  
} @Z(rgF{{  
} [5ethM  
9G+f/k,P  
64oxjF)  
/* Z_z#QX>=D  
**TestMethod.java .CV _\  
*/ Rc$h{0K8  
package NetFox; \^532FIw6  

NGzgLSm\  
))#'4  
public class TestMethod { TYS\95<  
W^g'}}]T  
_g
|acBF  
public TestMethod() a%
,fXp>  
{ ///xx/weblogic60b2_win.exe T{MC-j _T9  
try{ 4I~i)EKy6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [$\>~nj=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :iCM=k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); XF,<i1ZlM  
fileFetch.start(); )q^ Bj$  
} P;91~``
b-  
catch(Exception e){e.printStackTrace ();} e1 a*'T$z  
0Oxz3r%}r  
CmC0k-%w  
} b]
(o]
O{v  
hY;_/!_  
KsdG(.I+ek  
public static void main(String[] args) Y(i?M~3\t  
{ r'aY2n^O  
new TestMethod(); w+UV"\!G)Q  
} h8}8Lp(/'  
} YB!!/ SX4  
点击下载更多相关资料