http断点续传简单实现（java)

/* +FGw)>g8'm  
**SiteFileFetch.java fhp+Ep!0Y  
*/ .*,W%r?1n6  
package NetFox; sq;nUA=  
import java.io.*; vyXL F'L  
import java.net.*; Q\qI+F2?  
xfFsW^w  
so]p1@K  
public class SiteFileFetch extends Thread { Lt?k$U{qe)  
ebTwU]Nb
 
i9O;D*  
SiteInfoBean siteInfoBean = null; //文件信息Bean ./r#\X)dc  
long[] nStartPos; //开始位置 rJ^*8C!  
long[] nEndPos; //结束位置 >713H!uj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Tsc2;I  
long nFileLength; //文件长度 a*3h|b<  
boolean bFirst = true; //是否第一次取文件 3$#=*Zp  
boolean bStop = false; //停止标志 /@xL {  
File tmpFile; //文件下载的临时信息 /8Xd2-  
DataOutputStream output; //输出到文件的输出流 OY'6~w9  
J!"#N}[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） e{k)]]J  
public SiteFileFetch(SiteInfoBean bean) throws IOException MWHzrqCA  
{ hI}rW^o^  
siteInfoBean = bean; +h?Rb3=S  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); I;rh(FMV  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z-;I,\Y%  
if(tmpFile.exists ()) gg+!e#-X  
{ Q?WgGE4>  
bFirst = false; rpn&.#KS  
read_nPos(); $-l\&V++F  
} 9zac[tno  
else 9|5>?'CqP  
{ I5H#]U  
nStartPos = new long[bean.getNSplitter()]; 34s>hm=0.  
nEndPos = new long[bean.getNSplitter()]; lDF26<<\`  
} 5 cz6\A&  
<v+M~"%V  
=cKrp'  
?<h|Q~JH  
} N3SB-E+  
o)SA^5  
6SVh6o@]  
public void run() Ou,Eu05jt'  
{ jB-wJNP/  
//获得文件长度 Y1s3>`  
//分割文件 y1*z,"dx  
//实例FileSplitterFetch OJTEvb6nPg  
//启动FileSplitterFetch线程 IKVS7m  
//等待子线程返回 b_%W*Q  
try{ n}!D)Gx  
if(bFirst) @$] CC1Y  
{ O$$$1VHYo  
nFileLength = getFileSize(); YdiXj |k+  
if(nFileLength == -1) +x:-W0C:  
{ 3X]\p}]z  
System.err.println("File Length is not known!"); ow@1.5WL+  
} g4=6\vg  
else if(nFileLength == -2) DY'1#$;  
{ q@8j[15  
System.err.println("File is not access!"); #`Gh8n#  
} &XH{,fv$  
else t]PO4GA  
{ dd|/I1  
for(int i=0;i<nStartPos.length;i++) p&<X&D   
{ GFmVR2z_+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hY^-kdQ>M  
} .X(*mmH  
for(int i=0;i<nEndPos.length-1;i++) `
z]MQdE_w  
{ dX>l"))yR  
nEndPos = nStartPos[i+1]; -4!i(^w[m/  
} o;<oXv  
nEndPos[nEndPos.length-1] = nFileLength; L?~-<k  
} ({l!'>?  
} ?iQA>P9B  
wU=@,K  
;.wWw" )  
//启动子线程 ~IP3~m D  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; DGllJ_/Z  
for(int i=0;i<nStartPos.length;i++) ? 
W`?F  
{ *q/oS8vavd  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yg-uL48q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), U3zwC5}BN  
nStartPos,nEndPos,i); b6E,u*)"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #7~i.8L  
fileSplitterFetch.start(); ?a]uyw,  
} j)[ wX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0o+2]`q)Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); V$7SVq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u  teI[Q  
nEndPos = " + nFileLength); |(=`l  
// fileSplitterFetch[nPos.length-1].start(); &v
#*  
_Xn[G>1  
(!^(74  
//等待子线程结束 E'J| p7  
//int count = 0; <Hq|<^_K  
//是否结束while循环 utz!ElzA  
boolean breakWhile = false; c%
+9uu3  
Kpo{:a  
%TA3o71  
while(!bStop) 3B<$6  
{ Yy"05V.  
write_nPos(); nD$CY K  
Utility.sleep(500); MOIH%lpe
 
breakWhile = true; )D:I@`
*  
p6yC1\U!o  
'RlPj0Cg  
for(int i=0;i<nStartPos.length;i++) @qfVt  
{ 3PEv.hGx  
if(!fileSplitterFetch.bDownOver) h>6'M  
{ Xh,{/5m  
breakWhile = false; 9W{=6D86e  
break; C NNyz$  
} >g]kbes-\  
} C#<:x!  
if(breakWhile) 'y [eH  
break; 8-?.Q"D7%  

lglC1W-q  
;^Vsd\ac0  
//count++; 24)3^1P\V  
//if(count>4) ?dukK3u  
// siteStop(); _M/ckv1q@  
} i
R9 $E  
.O{2]e$  
`5[d9z/6  
System.err.println("文件下载结束！"); `5:Wv b>|  
} ^1vh5D  
catch(Exception e){e.printStackTrace ();} DHO6&8S  
} <|NP!eMsw8  
gL(ny/Ob9  
?v>!wuiP  
//获得文件长度 XHgwK@GU  
public long getFileSize()  $&96qsr  
{ +-=w`  
int nFileLength = -1; !e?GS"L~  
try{ ,%#FK|  
URL url = new URL(siteInfoBean.getSSiteURL()); zo-hH8J:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C:/O]slH  
httpConnection.setRequestProperty("User-Agent","NetFox"); {$,e@nn  
,F7W_f# @3  
')w:`8Tl  
int responseCode=httpConnection.getResponseCode(); XO+^q9  
if(responseCode>=400) 'ao<gTUbu  
{ :?s~,G_*l  
processErrorCode(responseCode); I @TR|  
return -2; //-2 represent access is error [];*9vxW  
} P%A^TD|  
31\l0Jg  
4=S.U`t7  
String sHeader; 5:%xuJD  
cF9bSY_Eh  
sas}k7m"  
for(int i=1;;i++) [R[]&\W  
{ Vu '3%~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bI 3o|  
//Utility.log(in.readLine()); =m.Lw  
sHeader=httpConnection.getHeaderFieldKey(i); +jePp_3$O  
if(sHeader!=null) QS:dr."k  
{ fr$E'+l)  
if(sHeader.equals("Content-Length")) !63
p?Q=  
{ _FXvJ}~m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m?DI]sIv#  
break; C?jk#T  
} Tf/j
d 3>  
} XdX1GH*C  
else @:u>  
break; qjQR0MC  
}  #nV F.  
} W($}G_j[B1  
catch(IOException e){e.printStackTrace ();} u`I&&  
catch(Exception e){e.printStackTrace ();} (- `h8M  
DPCB=2E  
~.99H  
Utility.log(nFileLength); 2Wwzcvs@  
#zflU99d  
6)i4&  
return nFileLength; EXDZehLD<]  
} Y
3W_Z  
E9e|+$  
~d]X@(G&  
//保存下载信息（文件指针位置） 0 @]gW  
private void write_nPos() ~9%L)nC2'  
{ :.8@ xVH  
try{ `@%hz%8Y  
output = new DataOutputStream(new FileOutputStream(tmpFile));
0c6b_%Rd  
output.writeInt(nStartPos.length); g\_J  
for(int i=0;i<nStartPos.length;i++) }LK +w+h~  
{ Vwxb6,}Z  
// output.writeLong(nPos); Jbv66)0M  
output.writeLong(fileSplitterFetch.nStartPos); 6Ih8~Hu  
output.writeLong(fileSplitterFetch.nEndPos); 9e5XS\  
} Kvx~2ZMx6  
output.close(); ?
8AV-rRX  
} W:5uoO]=<  
catch(IOException e){e.printStackTrace ();} mhh^kwW  
catch(Exception e){e.printStackTrace ();} z~8`xn,  
} 9
)P-<  
>6yA+?[:  
90g=&O5@O  
//读取保存的下载信息（文件指针位置） X#v6v)c  
private void read_nPos() `Vph=`0  
{ d\c?sYLv  
try{ ZC7ZlL_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 'PO+P~|oa&  
int nCount = input.readInt(); LtrE;+%2oz  
nStartPos = new long[nCount]; |
q+3X)Y  
nEndPos = new long[nCount]; =:neGqd\_E  
for(int i=0;i<nStartPos.length;i++) DIAHIV<  
{ %?2:1o  
nStartPos = input.readLong(); 2!@ER i  
nEndPos = input.readLong(); Y\7WCaSgi  
} W20qn>{z  
input.close(); n1Ic[cM}  
} <GdQ""X  
catch(IOException e){e.printStackTrace ();} qoZUX3{  
catch(Exception e){e.printStackTrace ();} r<)>k.] !  
} ,F;<Y9]  
fx74h{3u  
BYuoeN!  
private void processErrorCode(int nErrorCode) :
`Sd5b>  
{ gdj,e ^  
System.err.println("Error Code : " + nErrorCode); ;\mTm;]G  
} !3*:
6  
]K<mkUpY  
(Ts#^qC  
//停止文件下载 tKP zM  
public void siteStop() l|jb}9(J  
{ sKCfI]  
bStop = true; )@\Eibt2oH  
for(int i=0;i<nStartPos.length;i++) ^X\{MW'>4  
fileSplitterFetch.splitterStop(); sUe<21:  
E9N.b.Q)  
j&y>?Y&Sb  
} C@F3iwTtp  
} &sA@!  
//负责部分文件的抓取 7eU|iDYo  
**FileSplitterFetch.java TGuvyY  
*/ -~+Y0\%E  
package NetFox; b0:5i<"w6  
SbYsa  
2EAY`}Rl6.  
import java.io.*; [g Y.h/  
import java.net.*; hsJS(qEh.'  
*.P3fVlZ  
-. J@  
public class FileSplitterFetch extends Thread { n38l!m(.  
X"fSM #  
R=m9[TgBm  
String sURL; //File URL d@QC[$qXj  
long nStartPos; //File Snippet Start Position ;=i$0w9W  
long nEndPos; //File Snippet End Position n[c/L8j  
int nThreadID; //Thread's ID i-W!`1LH'  
boolean bDownOver = false; //Downing is over ] RLEyDB  
boolean bStop = false; //Stop identical iosL&*'8  
FileAccessI fileAccessI = null; //File Access interface Xxmvg.Nl  
:/6gGU>pu  
4+2hj*I  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j"J[dlm2M  
{ <1XJa2  
this.sURL = sURL; *<IQ+oat,a  
this.nStartPos = nStart; _VFL}<i  
this.nEndPos = nEnd; 5#}wI~U;  
nThreadID = id; !<AY0fpY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 R)u ${  
} ~'3
hK4  
O ]Stf7]%;  
$@}\T  
public void run() Y:3\z?oV[  
{ 0Ik}\lcn  
while(nStartPos < nEndPos && !bStop) 6JZ$;x{j  
{ (.J8Q  
@K}8zMmW#  
rxM)SC;P  
try{ r<XlIi  
URL url = new URL(sURL); -_xC,d
wK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JzZ9u
a  
httpConnection.setRequestProperty("User-Agent","NetFox"); |@lVFEl]  
String sProperty = "bytes="+nStartPos+"-"; x}*Y =Xh  
httpConnection.setRequestProperty("RANGE",sProperty); Ymr\8CG/  
Utility.log(sProperty); uL[%R2  
ckg8x&Z  
,`nl";Zc  
InputStream input = httpConnection.getInputStream(); C~([aH@-I  
//logResponseHead(httpConnection); mzoNXf:x  
y|0I3n]e  
AX
OR<Ns`  
byte[] b = new byte[1024]; %\n&iRwDF  
int nRead; \y*,N^wu  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) RI2Or9.  
{ 9X[}ik0  
nStartPos += fileAccessI.write(b,0,nRead); }5q
jGD  
//if(nThreadID == 1) 9e xHR&>{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8OW504AD  
} gbc])`aJ>  
[AHZOA  
lS:R##  
Utility.log("Thread " + nThreadID + " is over!"); `9yR,Xk=l  
bDownOver = true; QW_QizR>|  
//nPos = fileAccessI.write (b,0,nRead); .1 =8c\%  
} =P"Sm r  
catch(Exception e){e.printStackTrace ();} T1}9^3T?{  
} 1>1ii  
} 9v2(cpZ  
Fo1|O&>  
>=Z@)PAe  
//打印回应的头信息 ^-'t`mRl]d  
public void logResponseHead(HttpURLConnection con) ~"ij,Op,3  
{ @`X-=GCl  
for(int i=1;;i++) b[I;6HW  
{ 95G*i;E  
String header=con.getHeaderFieldKey(i); }M I9?\"q  
if(header!=null)
ecI[lB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -}?
ud3f<  
Utility.log(header+" : "+con.getHeaderField(header)); ;%R+]&J  
else fW
BI}~e  
break; UkY `&&ic  
} FSvtiNW<  
} 1jhGshhp  
jKcnZu  
e!5nz_J1}  
public void splitterStop() q&-A}]  
{ o5N];Nj  
bStop = true; `[+nz rLkO  
} ]o(&J7Z6-  
/?; 8F  
h4GR:`  
} ~!,Q<?  
k_=~ObA$g  
;5P>R[p  
/* @lau?@$ja  
**FileAccess.java j;O{Hvvz  
*//文件访问(定位，写) 9K8f ##3  
package NetFox; gJVakR&  
import java.io.*; A;sdrA  
.~4>5W"u  
bT@7&  
public class FileAccessI implements Serializable{ xy%lp{  
!P, 9Sg&5)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6t5)rlT  
RandomAccessFile oSavedFile; 1GY[
1M1^  
long nPos; <[^nD>t_  
"Yn<]Pa_  
F6T@YSP  
public FileAccessI() throws IOException [UI4YZu}  
{ HRx%m1H  
this("",0); -#b-@sD  
} 5hE8b {V  
7cn"@h rJ  
eBTy!!  
public FileAccessI(String sName,long nPos) throws IOException y@AKb  
{ i&^?p|eKa  
oSavedFile = new RandomAccessFile(sName,"rw"); G{rUqo  
this.nPos = nPos; .ukP)rGe  
oSavedFile.seek(nPos); ,z)7rU`  
} }[PbA4l.g  
AQ-P3`bCb  
L_jwM^8  
public synchronized int write(byte[] b,int nStart,int nLen) I0O)MR<  
{ }0uSm%,"  
int n = -1; yov:JnWo  
try{ {"e/3  
oSavedFile.write(b,nStart,nLen); .9WUp>  
n = nLen; c?d+>5"VX  
} 
Y,?  
catch(IOException e) pi5Al)0  
{ 0At??Zpy  
e.printStackTrace (); hE!3kaS  
} ,u(g#T  
x#|P-^  
6(oGU4  
return n; *ZGQ`#1.X6  
} b0E(tPw5c  
&P!^k0NJR  
)G ,LG0"-  
} XFmnZpqXH  
YjS|Ht->  
Lq LciD  
/* [_qBp:_j?s  
**SiteInfoBean.java }tx~y-QQ  
*/ uGLVY%N  
package NetFox; ,y2ur2  
8dUwJ"<5  
4ej$)AdW3  
public class SiteInfoBean { +U+c]Xgt  
KEYM@,'  
+zs;>'Sf  
private String sSiteURL; //Site's URL -.g5|B  
private String sFilePath; //Saved File's Path V* fDvr0  
private String sFileName; //Saved File's Name QsDab4  
private int nSplitter; //Count of Splited Downloading File fXIeCn  
7"*- >mg  
PpU : 4;en  
public SiteInfoBean() HK&F'\'}  
{//nSplitter的缺省值为5 1 EC
0wX  
//default value of nSplitter is 5 fg
l"ox  
this("","","",5); sNX$ =<E  
} V%ykHo  
)KBv[|  
p//">l=Ps  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _V:D7\Gs  
{ K]kL?-A#'  
sSiteURL= sURL; a+weBF#Z  
sFilePath = sPath; S3qUzK  
sFileName = sName; !h&hPY1  
this.nSplitter = nSpiltter; *i%!j/QDAP  
pBL{DgX  
(eO0Ic[c  
} f^%vIB ~[  
s977k2pp-  
2U|Nkm  
public String getSSiteURL() M_79\Gz"  
{ [.<vISRir  
return sSiteURL; ~01rc  
} 4eaC18?  
{_[l,tdZ  
fEQ<L!'  
public void setSSiteURL(String value) b>2u>4  
{ z+-k4  
sSiteURL = value; o"n^zG  
} &nz1[,  
'Fc&"(!||  
YT:<AJm  
public String getSFilePath() T_Y6AII  
{ ix!u#7  
return sFilePath; &I!2gf  
} B[$KnQM9Y  
uft~+w P  
4F:RLj9P!  
public void setSFilePath(String value) C|!E'8Rw  
{ 9w0 ^=  
sFilePath = value; j/Bzbjq"  
} lsio\ $  
X^xu$d6   
#Wc)wL-Tg  
public String getSFileName() Vn8Qsf1f  
{ '!f5|l9SC  
return sFileName; Y_)04dmr@[  
} 0IA '8_K  
{g )kT_  
]e"NJkcm  
public void setSFileName(String value) R9#Z=f,  
{ qx!IlO  
sFileName = value; BO h  
} Q kQd;y  
vNtbb]')m  
jg
Gn"}  
public int getNSplitter() ~RMOEH.o  
{ mU\$piei  
return nSplitter; ZjI^0D8  
} |x kixf4zz  
{'}Ofj  
KM\`,1?x92  
public void setNSplitter(int nCount) h2BD?y  
{ =8J\
;h  
nSplitter = nCount; XM=`(e o  
} P)}:lTe  
} j?8E >tM  
`o*eLLk  
74[}AA  
/* H
[G EAQO  
**Utility.java f,uxoAS  
*/ };KmMpBn  
package NetFox; m3|,c[M1  
f'.
yM*  
RdY#B;  
public class Utility { |6;.C1\,  
?=T&|pp  
{Rz`)qqE  
public Utility() ^#Z(&/5f0  
{ ! TRiFD  
+5HOT{wj  
[ z&y]~  
}
kO9yei  
k&?QeXW  
//线程睡眠 #".{i+3E  
public static void sleep(int nSecond) lA ,%'+-  
{ ![V<vIy  
try{ ']rh0?  
Thread.sleep(nSecond); "?il07+w%  
} mee-Qq:}  
catch(Exception e) EgO4:
8$h  
{ Gs9jX/#  
e.printStackTrace (); 0FW=8hFp,  
} Fb}9cpz{  
} R.fRQ>rI  
npe*A  
//日志 
5QT9  
public static void log(String sMsg) -^Lj~O  
{ v0y7N_U5n  
System.err.println(sMsg); p;H1,E:Re#  
} 4 IHl'*D[#  
_1hqD EM  
ILpB:g  
public static void log(int sMsg) jBQQ?cA  
{ *GDU=D}  
System.err.println(sMsg); <)&ykcB  
} LRI_s>7  
} rm cy-}e  
&]M<G)9  
T]my
hNk  
/* xtnB:3  
**TestMethod.java v{jl)?`~w  
*/ Vz#cb5:g  
package NetFox; +g;G*EP
7*  
HR}c9wy,q\  
GphG/C (  
public class TestMethod { *rbH|o8  
v#X? KqD  
vJ{\67tK  
public TestMethod() oT_,k}LIX  
{ ///xx/weblogic60b2_win.exe [sad}@R7  
try{ 3646.i[D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); jv7zvp  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vZKo&jUk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5M(?_qj  
fileFetch.start();
'"TBhisky  
} j4l7Tx  
catch(Exception e){e.printStackTrace ();} |fA[s7)  
g&za/F  
*= D$  
} _S[H:b$?  
!1l2KW<be  
}l/md/C0  
public static void main(String[] args) J+;.t&5R  
{ >Kr,(8rA  
new TestMethod(); N7E[wOP  
} &x;nP6mV  
} "<&F=gV  
点击下载更多相关资料