http断点续传简单实现（java)

/* Vu_QwWXO  
**SiteFileFetch.java 0T7""^'&  
*/ gCY%@?YyN  
package NetFox; Z |CL:)h  
import java.io.*; -mK;f$X  
import java.net.*; EG[Rda  
i"o %Gc  
&ywU^hBh  
public class SiteFileFetch extends Thread { =5m~rJ<
{  
Z]1jg>")  
i_6 Y
6  
SiteInfoBean siteInfoBean = null; //文件信息Bean #)N}F/Od^  
long[] nStartPos; //开始位置 5WvtvSO  
long[] nEndPos; //结束位置 /V@9!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {]6Pd`-  
long nFileLength; //文件长度 _B5v&#h(.  
boolean bFirst = true; //是否第一次取文件 u =%1%p,  
boolean bStop = false; //停止标志 m_g2Cep  
File tmpFile; //文件下载的临时信息 \bPSy0  
DataOutputStream output; //输出到文件的输出流 8%D 2G i  
{:0TiOP5x  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &`IC3O5  
public SiteFileFetch(SiteInfoBean bean) throws IOException \_J;i[
  
{ a8laPN  
siteInfoBean = bean; ~*Kk+w9H<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;HbAk`\1A  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^
6(Nu|6\@  
if(tmpFile.exists ()) ?m>!P@ M  
{ [=q&5'FY0  
bFirst = false; { vOr'j@  
read_nPos(); SV0h'd(b  
} UiLiy?EJ  
else 5ps7)]  
{ B6#^a  
nStartPos = new long[bean.getNSplitter()]; %RS8zN  
nEndPos = new long[bean.getNSplitter()]; X1PXX!]lo[  
} oF0BBs$  
p`-Oz]  
FH}2wO~_  
J-wF2*0r<  
} Td/J6Q90  
cg]>*lH  
!m<v@SmL\  
public void run() &3_.k  
{ qlgo#[i  
//获得文件长度 p,K]`pt=  
//分割文件 ,`O.0e4pn  
//实例FileSplitterFetch QpZCU]  
//启动FileSplitterFetch线程 dF<GuS;l5  
//等待子线程返回 $)6%LG_@  
try{ Hlj_oDL  
if(bFirst) lOuO~`,J  
{ U+FI^Xrt#  
nFileLength = getFileSize(); /pS Y~*  
if(nFileLength == -1) Qt`;+N(  
{ oW \k%Vj  
System.err.println("File Length is not known!"); yrVk$k#6}  
} 7U,[Ruu  
else if(nFileLength == -2) A5[iFT
>  
{ M\rZr3  
System.err.println("File is not access!"); kt;uB X3  
} }a?(}{z-  
else F2:nL`]b[  
{ g<(\#F}/  
for(int i=0;i<nStartPos.length;i++) JRYCM}C]  
{ FZ~^cK9g:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *H({q`j33k  
} <*F!A' w2o  
for(int i=0;i<nEndPos.length-1;i++) "F+m}GJ=a  
{ Q^!x8oUF  
nEndPos = nStartPos[i+1]; [;RO=  
} @&xWd{8'  
nEndPos[nEndPos.length-1] = nFileLength; [ qx[ 0  
} QDdH5EfY  
} gql^Inx<  
k ^(RSu<  
d$T856  
//启动子线程 3F ]30  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2{;~Bgd  
for(int i=0;i<nStartPos.length;i++) s5
cY>  
{ %;MM+xVVX  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NA;OT7X[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), SWWeN#Q  
nStartPos,nEndPos,i); w1J%%//(h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <A
`zK   
fileSplitterFetch.start(); Mj5&vs~n;  
} fDD^?/^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P4{!
/&/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )N'rYS'9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sRKoM  
nEndPos = " + nFileLength); k|D =Q  
// fileSplitterFetch[nPos.length-1].start(); ,|G~PC8  
YM.Q?p4g  
G'IRqO*]  
//等待子线程结束 wx[Y2lUh6  
//int count = 0; uP NZ^lM  
//是否结束while循环 # ;3v4P  
boolean breakWhile = false; ki=]#]rg  
fZka$ 4  
vMv? fE"  
while(!bStop) 'LW~_\  
{ eB2a1<S&@  
write_nPos(); R.P|gk  
Utility.sleep(500); 4IGn,D^  
breakWhile = true; /n-!dXi  
o7sIpE9  
w gU2q|  
for(int i=0;i<nStartPos.length;i++) =GJ)4
os  
{ ~b;u1;ne  
if(!fileSplitterFetch.bDownOver) h6~H5X  
{ ZBsV  
breakWhile = false; n&\DJzW\#  
break; 7Q>bJ Ek7  
} /:-Y7M*  
} 1.IEs:(;  
if(breakWhile) @aY>pr5!  
break; HyGu3  
EAZLo;  
Z%$tV3a?  
//count++; 7;r Jr&.)  
//if(count>4) hywy(b3  
// siteStop(); )PCh;P0C  
} }=$>w@mJ  
i)=dp!Bx^  
%2,'x  
System.err.println("文件下载结束！"); NnTAKd
8  
} <:ptNGR  
catch(Exception e){e.printStackTrace ();} R?5v//[  
} `/RcE.5n\@  
F~;UD<<"H  
":W$$w<  
//获得文件长度 x.kIzI5  
public long getFileSize() PQvpJFpb~h  
{ SbK6o:[  
int nFileLength = -1; JxmFUheLt  
try{ "(+p1  
URL url = new URL(siteInfoBean.getSSiteURL()); |] cFsB#G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D*}_

L   
httpConnection.setRequestProperty("User-Agent","NetFox"); mTgsvC  
lOEB ,/P  
w
itx_r  
int responseCode=httpConnection.getResponseCode(); Z# o;H$  
if(responseCode>=400) ')zf8>,  
{ U^ ;H{S  
processErrorCode(responseCode); vR*p1Kq:  
return -2; //-2 represent access is error aW*8t'm;m'  
} E'+?7ZGWj  
Zonr/sA~  
d*R('0z{  
String sHeader; @XQItc<  
8>AS
T,  
^u-;V
oK  
for(int i=1;;i++) 0x,NMS  
{ hQ\W~3S55  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1w}DfI  
//Utility.log(in.readLine()); T )!kJ;vc  
sHeader=httpConnection.getHeaderFieldKey(i); LOi/+;>  
if(sHeader!=null) ,t@B]ll  
{ ZVni'ym  
if(sHeader.equals("Content-Length")) ?5j}&Y3  
{ QE4TvnhK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =58:e7(df  
break; cm17hPe`}n  
} ;5&=I|xqe  
} H>Q X?>j  
else Lq]t6o]  
break; kK_9I (7c  
} s_ %LU:WC  
} -)9aY.  
catch(IOException e){e.printStackTrace ();} >)6k)$x%%  
catch(Exception e){e.printStackTrace ();} "U|u-ka8B  
H8V@KB  
Nin7AOO  
Utility.log(nFileLength); S<81r2LT  
ub9,Wd"^  
e'T|5I0K  
return nFileLength; 8;$zD]{D1  
} ZmAo9>'Kg  
MuF{STE>->  
gt\*9P   
//保存下载信息（文件指针位置） bkS-[rW  
private void write_nPos() (y5]]l  
{ |-`-zo4z  
try{ W%@0Ym`7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _j2q  
output.writeInt(nStartPos.length); 4uE|$  
for(int i=0;i<nStartPos.length;i++) [7Liken  
{ Y*
0j/91  
// output.writeLong(nPos); j5!pS xOC  
output.writeLong(fileSplitterFetch.nStartPos); @Px_\w  
output.writeLong(fileSplitterFetch.nEndPos); 85vyt/.,k  
} P~h0Ul  
output.close(); -=GmI1:=$4  
} 6r)B|~,OA  
catch(IOException e){e.printStackTrace ();} Ntlbn&lc;D  
catch(Exception e){e.printStackTrace ();} t/J|<Ooj?  
} wUKt$_]``  
51 "v`O+  
IHwoG(A~<  
//读取保存的下载信息（文件指针位置） 6+/BYN!&4  
private void read_nPos() B4{F)Zb  
{ >6gduD!6I  
try{ ]SUW"5L-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9#1
Jie$  
int nCount = input.readInt(); _-z;  
nStartPos = new long[nCount]; C ett*jm_  
nEndPos = new long[nCount]; <q:2' 4o  
for(int i=0;i<nStartPos.length;i++) -IS$1  
{ ZM_-g4[H  
nStartPos = input.readLong(); FDTC?Ii O  
nEndPos = input.readLong(); >:|jds#  
} 7~H"m/;U&  
input.close(); ne# %Gr  
} +HEL^  
catch(IOException e){e.printStackTrace ();} vz^=o'  
catch(Exception e){e.printStackTrace ();} { {+:Vy  
} <G#Q f|&  
ql7N\COoq  
&IP`j~b  
private void processErrorCode(int nErrorCode) Dv}VmC""  
{ l}W"> yQ0  
System.err.println("Error Code : " + nErrorCode); $d Nmq  
} 9s#*~[E*  
3w
8v.J8q  
6\RZ[g
A?  
//停止文件下载 o$Z]qhq  
public void siteStop() O +Xu?W]  
{ C,$7fW{?  
bStop = true; 6 -IThC  
for(int i=0;i<nStartPos.length;i++) H={5>;8G  
fileSplitterFetch.splitterStop(); v*^'|QyM7  
qv8B$}FU  
b$Q#Fv&P  
} __i))2  
} oT- Y  
//负责部分文件的抓取 Vo9FlYj  
**FileSplitterFetch.java h%&2M58:  
*/ oiItQ4{<  
package NetFox; K Vnz{cx`  
-;o0)DwZ  
]Uul~T
 
import java.io.*; ; Z2  
import java.net.*; !-tVt D  
!=]cASPGD  
@gi / 1cq  
public class FileSplitterFetch extends Thread { sPRs;to-  
QLb!e"C  
|z`AIScT  
String sURL; //File URL QxiAC>%K  
long nStartPos; //File Snippet Start Position t]+h.  
long nEndPos; //File Snippet End Position \N.Bx
  
int nThreadID; //Thread's ID LDdgI  
boolean bDownOver = false; //Downing is over ?zK\!r{  
boolean bStop = false; //Stop identical Z@bKYfGM  
FileAccessI fileAccessI = null; //File Access interface )| F
O>  
A[H"(E#k  
&,'CHBM  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1WAps#b.  
{ MZ_dI"J,  
this.sURL = sURL; d[sY]_ dj  
this.nStartPos = nStart; rGQY  
this.nEndPos = nEnd; v4r%'bA  
nThreadID = id; in2m/q?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位
jR"ACup(  
} <1E5[9 q  
Z8o8>C\d9/  
8i^d*:R  
public void run() @UW*o&pGqL  
{ (#rhD}  
while(nStartPos < nEndPos && !bStop) Q$x 3uH\@  
{ !DXK\,;>  
5 &s<&h  
*_eY +\j  
try{ [N0"mE<  
URL url = new URL(sURL); IhXP~C6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )odz/\9n3c  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZX0!BS  
String sProperty = "bytes="+nStartPos+"-"; T_oL/x_;  
httpConnection.setRequestProperty("RANGE",sProperty); M! uE#|  
Utility.log(sProperty); x*wr8$@J  
t{O
2JF#5u  
J"Nn.iVq  
InputStream input = httpConnection.getInputStream(); <,Fj}T-  
//logResponseHead(httpConnection); /;`-[  
QVe<Z A8N;  
.<Jq8J  
byte[] b = new byte[1024]; U)D}J_Zi(  
int nRead; j~O"=?7!O  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) VTn6@z_ x  
{ h 2C9p2.  
nStartPos += fileAccessI.write(b,0,nRead); xvW# ~T]  
//if(nThreadID == 1) PF:'
dv  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gy!bPVe
 
} Im@Yx^gc  
,ZvlKN  
9.Yn]O  
Utility.log("Thread " + nThreadID + " is over!"); .>^U mM  
bDownOver = true; kjj?X|Un  
//nPos = fileAccessI.write (b,0,nRead); <'vtnz  
} W=2#Q2)  
catch(Exception e){e.printStackTrace ();} <4%PT2R  
} goc"+K  
} Q`BB@E  
cL:hjr"  
R?}<CjI  
//打印回应的头信息 S{zl<>+  
public void logResponseHead(HttpURLConnection con) xDIl  
{ #z9@x}p5g  
for(int i=1;;i++) 1V;,ZGI*  
{ +kT o$_Wkz  
String header=con.getHeaderFieldKey(i); Y|aaZ|+  
if(header!=null) |],ocAN{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); H~?p
,h  
Utility.log(header+" : "+con.getHeaderField(header)); eI+p  
else HQ^:5XH  
break; fU'[lZ  
} xi
=Qxgx0I  
} /086qB|  
yVH>Q-{  
Zmy:Etqi  
public void splitterStop() RNb"O{3  
{ PRN%4G  
bStop = true; e# KP3Lp  
} !Z%pdqo`.  
47^
7S=  
s^GE>rf  
} $%"~.L4  
JvM:xy9  
E 7"`D\*  
/* MzI
n~[\  
**FileAccess.java EN)0b,ax  
*//文件访问(定位，写) 2,G9~<t  
package NetFox; 'Jl73#3  
import java.io.*; =7-@&S=?s  
5Pd^Sew  
cB}6{c$_sW  
public class FileAccessI implements Serializable{ H`NT`BE  
Vn6]h|vm  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #)( D_*  
RandomAccessFile oSavedFile; pxHJX2  
long nPos; iTJE:[W"y  
qfyuq]  
_hi8mo  
public FileAccessI() throws IOException ^q/_D%]C  
{ N6!$V7oT  
this("",0); }RZN3U=  
} "SU O2-Gj  
W_h!Pu
j_  
$J]o\~Z J  
public FileAccessI(String sName,long nPos) throws IOException yQquGu  
{ >?GCH(eW%  
oSavedFile = new RandomAccessFile(sName,"rw"); io*iA<@Gx  
this.nPos = nPos; Dh .<&ri
 
oSavedFile.seek(nPos); m]'P3^<{P  
} ?Z"<&ts
Z  
'<&rMn  
p-B |Gr|  
public synchronized int write(byte[] b,int nStart,int nLen) WS1#i\0  
{ .a `ojT  
int n = -1; 2g%p9-MO]I  
try{ $ 1v'CT  
oSavedFile.write(b,nStart,nLen); F+?g0w['  
n = nLen; FuFA/R=x/  
} 9v(k<('_  
catch(IOException e) zl@hg<n  
{ "[\),7&03  
e.printStackTrace (); iKE
Hwm  
} U].3vju`c  
oPR?Ar  
"j?\Ze*  
return n;
nSB@xP#&  
} JI|MR#_u  
td(4Fw||1y  
RV_+-m{]  
} 9NausE40  
=J^FV_1rJ  
ZUaqv  
/* OsNJ;B  
**SiteInfoBean.java P6u%-#  
*/ Q ;$NDYV1  
package NetFox; 0v'!(&m  
?T
Y/'-M5  
;BYv&(#u1q  
public class SiteInfoBean { /%i:(Ny  
#iP5@:!Wm~  
')1p  
private String sSiteURL; //Site's URL yo_;j@BGR  
private String sFilePath; //Saved File's Path  4,?ZNyl  
private String sFileName; //Saved File's Name n@y*~sG]  
private int nSplitter; //Count of Splited Downloading File }TwSSF|}3  
YQ7tZl;:t  
>m8~Fs0  
public SiteInfoBean() 0i/!nke.  
{//nSplitter的缺省值为5 D:Fi/JY~  
//default value of nSplitter is 5 \* SEj&9  
this("","","",5); e6uVUzP4  
} FlepM*  
)G@/E^ySM  
70yM]C^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) peGh-  
{ ;@V1*7y  
sSiteURL= sURL; g0A,VX:2  
sFilePath = sPath; v}BXH4&Y  
sFileName = sName; 's 'H&sa  
this.nSplitter = nSpiltter; : 5<u!-}  
Q'Vejz/  
[.c'22R6  
} s:Io5C(  
D~7L~Q]xI  
dmk_xBy s|  
public String getSSiteURL() A!^gF~5  
{ HR$;QHl~F  
return sSiteURL; esK0H<]  
} Ygfv?  

_p\O!y  
.0iHI3i^  
public void setSSiteURL(String value) b]Z>P{ j  
{ q,*([yX  
sSiteURL = value;
v7G&`4~  
} 2*}qQ0J  
Geyj`t  
sL\W6ej  
public String getSFilePath() fQ_(2+FM  
{ B),Z*lpC  
return sFilePath; {x<yDDIv_  
} 0:qR,NW^#  
xoyH5ZK@  
Wd]MwDcO  
public void setSFilePath(String value) *1CZRfWI  
{ vDcYz,  
sFilePath = value; JFh_3r'  
} zb& 3{,  
|7%#
z~rT  
iBaz1pDc  
public String getSFileName() EN{o3@ O'  
{ j|2s./!Qg  
return sFileName; AQIBg9y7  
} tLo_lLn*~%  
q-TDg0  
,BE4z2a  
public void setSFileName(String value) )|j?aVqZ  
{ %3mh'Z -[f  
sFileName = value; d{*e0  
} T7~Vk2o%(  
DBk]2W|i  
POt8G  
public int getNSplitter() vbSycZ2M7  
{ o2W^!#]=
 
return nSplitter; eGj[%pk  
} 5Za%EaW%G  
g~]?6;uu  
k07pI<a?  
public void setNSplitter(int nCount) <_~e/+_.  
{ F7IZ;4cp  
nSplitter = nCount; ^]ig*oS\`  
} "]ZDs^7  
} :FX|9h  
8KHT"uc'*J  
`$i/f(t6`  
/* XWv;l)  
**Utility.java #MAXH7[  
*/ 5Sz}gP('  
package NetFox;  95l)w
 
9#b/D&pX5  
^b^}6L'Z  
public class Utility { ]1&}L^a  
9N V.<&~  
MeW?z|x`'  
public Utility() u?I2|}#  
{ l" +q&3Zx  
.T\_4C  
E8"$
vl&c]  
} L=wpZ`@ y  
?z0N-A2C2  
//线程睡眠 8ib%CYR  
public static void sleep(int nSecond) MkX=34oc^  
{ }0~X)Vgm(  
try{ 2VaKt4+`  
Thread.sleep(nSecond); qA5 Ug  
} 3H,?ZFFGz  
catch(Exception e) J/B`c(  
{ jchq\q)_z  
e.printStackTrace (); {pk]p~  
} R(p3*t&n
 
} W(\^6S)  
O#?@'1  
//日志 IA680^  
public static void log(String sMsg) VCQo3k5 {  
{ tQ(4UHqa~  
System.err.println(sMsg); v:?l C<,  
} oMHTB!A=2  
6QAhVg: A  
ppzQh1  
public static void log(int sMsg) y85R"d  
{ 6|Xe ],u  
System.err.println(sMsg); t4Pi <m:7  
} D`3`5.b  
} FA!!S`{\  
()e|BFL.  
&gsBbQ+qA  
/* p> g[: ~  
**TestMethod.java vW4n>h}]  
*/ AL;4-(KH  
package NetFox; %uDH_J|^  
#*X\pjZ  
Eo>EK>  
public class TestMethod { 
v-DZW,  
Fs&r^ [/b  
t^~Qv  
public TestMethod() XeX`h
_  
{ ///xx/weblogic60b2_win.exe d r$E:kr  
try{ nYE%@Up  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pD;fFLvN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :f~qt%%/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }/2M?W0  
fileFetch.start(); (9Q@I8}Iy  
} %"^8$A?>,k  
catch(Exception e){e.printStackTrace ();} e%C_>  
{A'_5 X9  
iTVZo?lVo  
} T{)_vQ  
v?_L_{x;W  
(D0\uld9  
public static void main(String[] args) tE,& G-jU  
{ EYA=fU  
new TestMethod(); '}$$0S.DC  
} yt<h!k$ _P  
} +`tk LvM  
点击下载更多相关资料