http断点续传简单实现（java)

/* J3IRP/*z  
**SiteFileFetch.java
d1bhJK  
*/ "i%jQL'.  
package NetFox; LS6ry,D"7  
import java.io.*; 8W,*e
ke?  
import java.net.*; d.cCbr:  
C0<YH "  
U&Ab#m;  
public class SiteFileFetch extends Thread { _-TOeP8#94  
HsH<m j  
HH zEQV Lh  
SiteInfoBean siteInfoBean = null; //文件信息Bean  5~s{N  
long[] nStartPos; //开始位置 s.rT]  
long[] nEndPos; //结束位置 ;($1Z7j+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 wT/6aJoX  
long nFileLength; //文件长度 ]/44Ygz/  
boolean bFirst = true; //是否第一次取文件 iRs V#s  
boolean bStop = false; //停止标志 Bc[6*Y,%T  
File tmpFile; //文件下载的临时信息 M2p<u-6 "  
DataOutputStream output; //输出到文件的输出流 Rcf=J){D6  
G#lg|# -#  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5#!ogKQ(i  
public SiteFileFetch(SiteInfoBean bean) throws IOException [%~^kq=|  
{ [g
ZDQcU  
siteInfoBean = bean; k%Eh{dA  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i|4_m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xYwkFB$$*  
if(tmpFile.exists ()) `xIh\q  
{ (I
~\,[  
bFirst = false; +?V0:Kz]  
read_nPos(); [+gzdLad  
} l&|)O6N  
else 4>k I^  
{ -[$&s FD  
nStartPos = new long[bean.getNSplitter()]; JY@X2'>v/  
nEndPos = new long[bean.getNSplitter()]; g@u;Y5  
} O<`,,^4w/  
-l JYr/MSL  
<jFSj=cIL  

k*Pz&8|  
} @h(!<Ux_  
c'rd$  
kwF]TO S  
public void run() [>p6   
{ 4>_d3_1sn  
//获得文件长度 Qi:j)uDW  
//分割文件 ~p^7X2% !  
//实例FileSplitterFetch Qc3?}os2  
//启动FileSplitterFetch线程 )E~_rDTl  
//等待子线程返回 QkE,T0,/?h  
try{ Ut_mrb+W  
if(bFirst) !.X_/$c  
{ @'gl~J7  
nFileLength = getFileSize(); :t5uDKZ_j)  
if(nFileLength == -1) &57U? oY  
{ !qw4mN  
System.err.println("File Length is not known!"); ,R}Z=w#  
}
$}4K`Iu  
else if(nFileLength == -2) 2&x7W*  
{ oZ-FF'  
System.err.println("File is not access!"); GA ik;R  
} 8f-:d]  
else 4 l1 i>_R  
{ @G(xaU'u  
for(int i=0;i<nStartPos.length;i++) JCcQd01z  
{ {,Fcd(MU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r{Z[xWIX  
} SB1[jcJ  
for(int i=0;i<nEndPos.length-1;i++) ]>vf9]  
{ X'@f"=v9k  
nEndPos = nStartPos[i+1]; hHEPNR[.  
} $+TYvA'N  
nEndPos[nEndPos.length-1] = nFileLength; ?`aTu:1#Z  
} ((cb4IX  
} 6Hn)pD#U  
m#MlH=-  
agW9Go_F[  
//启动子线程 B52H(sm  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; o\60n  
for(int i=0;i<nStartPos.length;i++) pUhc3L  
{ *:j-zrwu&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L;Vq j]_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), L~ 2q1  
nStartPos,nEndPos,i); pg!`SxFD  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xx0k$Dqt2I  
fileSplitterFetch.start(); |!xpYT:  
} KGQC't  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Xy!&^C` J`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qu
RPg
)
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `VXZ khm  
nEndPos = " + nFileLength); */Cj$KY70  
// fileSplitterFetch[nPos.length-1].start(); 7t3X`db  
^r4|{  
_k|g@"  
//等待子线程结束 0 {,h.:  
//int count = 0; V&R$8tpz  
//是否结束while循环 GmAj</~  
boolean breakWhile = false; K plM['uF  
JaFUcpZk$  
eQ\jZ0s;p  
while(!bStop) 2/EK`S  
{ u?Z <n:  
write_nPos(); `I{tZ$iD  
Utility.sleep(500); ?UJSxL  
breakWhile = true; ?~ ?Hdv  
{wv&t R;  
$W*|~}F/Ap  
for(int i=0;i<nStartPos.length;i++) F"v:}Vy|   
{ 9M]^l,
 
if(!fileSplitterFetch.bDownOver) |=u96G~N  
{ 6+)x7g1PL  
breakWhile = false; shNE~TA  
break; k{{hZ/om  
} wn1, EhHt  
} *(p7NYf1  
if(breakWhile) }+_9"YQ:  
break; {( dP  
44j,,
k  
cafsMgrA  
//count++; }U i_ynZ!  
//if(count>4) W6M jQ%f  
// siteStop(); vs\|rLa  
} jOv~!7T  
H@4/#V|Uy  
qS|AdkNL  
System.err.println("文件下载结束！"); E#a
ZvE  
} =R2l3-HA=  
catch(Exception e){e.printStackTrace ();} DU`v J2  
} 'QnW9EHLF  
|e+aZ%g  
BtID;^Dz  
//获得文件长度 M2L0c
?  
public long getFileSize() +nzTxpcP@K  
{ !%V*UR9  
int nFileLength = -1; 1xIFvXru  
try{ T$IUKR  
URL url = new URL(siteInfoBean.getSSiteURL()); E$R_rX4x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wcl!S
{  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8UYJye8  
j)BQMtt&U  
_<3r'Y,  
int responseCode=httpConnection.getResponseCode(); M_; w%FV  
if(responseCode>=400)  VmYBa(  
{ x*J|i4  
processErrorCode(responseCode); Y6a$gXRT  
return -2; //-2 represent access is error lU&Q^Zj`  
} El+Ft.7  
mQL8QW[c  
s6IP;}  
String sHeader; ?jFc@t*\:  
0NrTJ R`  
fSr`>UpxC  
for(int i=1;;i++) ]Cr]Pvab{  
{ %pqL-G  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /xJY7yF  
//Utility.log(in.readLine()); Uqr
{,-]5v  
sHeader=httpConnection.getHeaderFieldKey(i); 5c)<'EP  
if(sHeader!=null) MorW\7-}  
{ }`#B
f  
if(sHeader.equals("Content-Length")) t+J)dr  
{ zG<0CZQ8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (<n>EF#  
break; [m %W:Ez  
} Nv{eE<<6  
} Xa)7`bp<  
else {)@ j77P  
break; T*8_FR<  
}  J(^ >?d'  
} 69rwX"^  
catch(IOException e){e.printStackTrace ();} F46O!xb%  
catch(Exception e){e.printStackTrace ();} v23TL
  
7pd$?=__I  
sb 8dc  
Utility.log(nFileLength); gn364U a  
@ E >eq.m  
0T=jR{j!o  
return nFileLength; uV!MW=
)  
} C_C$5[~-:  
9X.gg$P  
C5cFw/',  
//保存下载信息（文件指针位置） ')rD?Z9 ^  
private void write_nPos() b6]e4DL:R  
{ e`vUK.UoW  
try{ {;\%!I  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (5>{?dR)|  
output.writeInt(nStartPos.length); |^Ur  
for(int i=0;i<nStartPos.length;i++) u^!&{q  
{ E $<;@  
// output.writeLong(nPos); ??q!jm-m  
output.writeLong(fileSplitterFetch.nStartPos); FDl,Ey^r/  
output.writeLong(fileSplitterFetch.nEndPos); A7.JFf>  
} rpx0|{m  
output.close(); =[APMig,n  
} EmF]W+!z%  
catch(IOException e){e.printStackTrace ();} FW/)uf3I  
catch(Exception e){e.printStackTrace ();} A<a2TXcIE3  
} [GOX0}$?  
,b.kw}k  
r,QJG$ Jo  
//读取保存的下载信息（文件指针位置） #%;<FFu\  
private void read_nPos() Q.*'H_Y  
{ p?_'|#tz  
try{ Y7*'QKz2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9&&kgKKGQ  
int nCount = input.readInt(); m)(SG  
nStartPos = new long[nCount]; W6)dUi :"  
nEndPos = new long[nCount]; C5BzWgK  
for(int i=0;i<nStartPos.length;i++) G#^m<G
^M  
{ </8be=e7p  
nStartPos = input.readLong(); LRhP7D+A  
nEndPos = input.readLong(); S$Qr@5  
} 6vMDm0sv  
input.close(); 3zk:59  
} t*eleNYeS~  
catch(IOException e){e.printStackTrace ();} c9 gz!NE  
catch(Exception e){e.printStackTrace ();} ^ yY{o/6  
} lR|$*:+  
6JUav."`~  
3we.*\2$  
private void processErrorCode(int nErrorCode) xU#]w6  
{ Q9Q!9B@  
System.err.println("Error Code : " + nErrorCode); 5
?<|3  
} cr2{sGn|  
{yGZc3e1j  
!pG+Ak?  
//停止文件下载 2O}s*C$Xav  
public void siteStop() de*,MkZN  
{ |`N$>9qN  
bStop = true; ?
v0A/68s#  
for(int i=0;i<nStartPos.length;i++) XfD z #  
fileSplitterFetch.splitterStop(); p_D on3  
Y8x(#qp,  
hWl""66+5  
} K7)j  
} zpBBnlq  
//负责部分文件的抓取 !"Z."fm*  
**FileSplitterFetch.java g}\U, (  
*/ ?6_"nT*}  
package NetFox; Ah(\%35&  
Ak<IHp^Q  
dj8F6\  
import java.io.*; 48R]\B<R{  
import java.net.*; b'1/cY/!  
Q1P,=T@  
$8<j5%/ $M  
public class FileSplitterFetch extends Thread { GapX$Jb,p  
zav*  
TmRrub  
String sURL; //File URL )Tyky%P+iI  
long nStartPos; //File Snippet Start Position l5":[C$  
long nEndPos; //File Snippet End Position Hsd|ka$x>  
int nThreadID; //Thread's ID ==PQ-Ia  
boolean bDownOver = false; //Downing is over UKt/0Ze  
boolean bStop = false; //Stop identical ]6?c8/M  
FileAccessI fileAccessI = null; //File Access interface =B3!jir  
FFD*e-i  
GU;TK'Yy?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException jSUAU}u!M  
{ '91u q  
this.sURL = sURL; FJ3:}r6 "  
this.nStartPos = nStart; %XDip]+rb  
this.nEndPos = nEnd; 
A>&>6O4  
nThreadID = id; Bd N{[2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sWojQ-8}  
} Wo1V$[`Dy  
F3H:I"4  
P?WT)C2)u  
public void run() $=@9 D,R  
{ 7(nz<z p  
while(nStartPos < nEndPos && !bStop) <:kTTye|  
{ c(_oK ?  
q\z=z$VR  
?,+C!R?  
try{ S
evfxR  
URL url = new URL(sURL); &cn%4Er  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &y+PSa%n  
httpConnection.setRequestProperty("User-Agent","NetFox"); HNkZ1+P {  
String sProperty = "bytes="+nStartPos+"-"; Uy_}@50"l  
httpConnection.setRequestProperty("RANGE",sProperty); >%jEo'0;_  
Utility.log(sProperty); 3;-@<9  
Jnu}{^~  
rSc,\upz  
InputStream input = httpConnection.getInputStream(); a?xq*|?  
//logResponseHead(httpConnection); bH)8UQR%  
*x#&[>  
y(wqcDok|n  
byte[] b = new byte[1024]; (c*7VO;  
int nRead; Ztpm_P6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9$4/frd  
{ Hc_hO  
nStartPos += fileAccessI.write(b,0,nRead); c?V*X-  
//if(nThreadID == 1) U#~nN+SIt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r-\T}e2Gz  
} oE|u;o
 
}77=<N br  
fjK]m.w  
Utility.log("Thread " + nThreadID + " is over!"); B1i!te}*  
bDownOver = true; 2A18hP`^  
//nPos = fileAccessI.write (b,0,nRead); DbNi;m  
} >w]k3MC  
catch(Exception e){e.printStackTrace ();} w7*b}D@65\  
} P/1UCITq}  
} |<+|Du1  
L]L~TA<D9i  
@e?[oojrM  
//打印回应的头信息 i1_>>49*  
public void logResponseHead(HttpURLConnection con) Kj1#R
 
{ D0E"YEo\nv  
for(int i=1;;i++) 7&;jje[ <g  
{ pb2{J#  
String header=con.getHeaderFieldKey(i); n[cyK$"  
if(header!=null) f)s_e  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :x*|lz[  
Utility.log(header+" : "+con.getHeaderField(header)); &L~31Ayj&  
else wor'=byh\  
break; 5 1CU@1Ie  
} 2Ws/0c  
} ~|B!.+  
yM#trqv
5  
O^="T^J  
public void splitterStop() C[<\ufclD  
{ _ry En  
bStop = true; .X=M!  
} E.Q} \E  

Z :i"|;  
.Zo9^0`C  
} ~C*6V{Tj  
a ~iEps  
'N5r2JL[w  
/* t=pkYq5t8  
**FileAccess.java '/qe#S  
*//文件访问(定位，写) U%PMV?L{  
package NetFox; ?[4khQt  
import java.io.*; H1b%:KRVK  
RKJWLofX&  
!CMVZf;u  
public class FileAccessI implements Serializable{ \,IDLXqp  
A)p!w aG  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 y7G|P~td  
RandomAccessFile oSavedFile; =z/mI y<  
long nPos; *[5#g3  
_G8y9!J  
$Qc%9p @i  
public FileAccessI() throws IOException u'n%BVt
 
{ 1sJJ"dC.w  
this("",0); :V1ZeNw  
} 9NoPrR=x1  
1bAp{u&  
,`2xfVa-  
public FileAccessI(String sName,long nPos) throws IOException ['YRY B  
{ ~hw4gdtS  
oSavedFile = new RandomAccessFile(sName,"rw"); F^v{Jqc  
this.nPos = nPos; Z5^UF2`Q  
oSavedFile.seek(nPos); @3=<wz<  
} >0okb3+  
LZbHK.G=  
R =c  
public synchronized int write(byte[] b,int nStart,int nLen) lVBy&f  
{ H.S|njn:r  
int n = -1; jQlK-U=oi  
try{ 30v1VLR_)  
oSavedFile.write(b,nStart,nLen);
b,V=B{(~  
n = nLen; oDDH;Q"M(  
} 5GpK
X  
catch(IOException e) ~SUl,Cs  
{ rca"q[,  
e.printStackTrace (); !Yi<h/:  
} Iur} ZA
z  
v%e"4:K}?  
8@#Y <{  
return n; 8[p6C Jl)  
} 0#nXxkw  
4Lq]yUj  
t/BiZo|zl  
} Gjh7cm>  
;rdLYmmx^  
`d;izQ1_=  
/* kqB00 ;  
**SiteInfoBean.java {v'Fg  
*/ PG]mwaj])  
package NetFox; A
UpC HG7  
pjn%CR`;  
Pz
!yIj  
public class SiteInfoBean { Z'kYf  
PiQs><FK8  
/T(~T  
private String sSiteURL; //Site's URL k/Ro74f=  
private String sFilePath; //Saved File's Path gJv^v`X  
private String sFileName; //Saved File's Name -"L6^IH7  
private int nSplitter; //Count of Splited Downloading File KO"iauW  
$B/cj^3  
kniMXeiu  
public SiteInfoBean() q|2C>{8  
{//nSplitter的缺省值为5 j!H?dnE||  
//default value of nSplitter is 5 =h!m/f^x  
this("","","",5); FeMu`|2  
} Xy<KvFy  
Vs{sB*:
 
\2b9A'd>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )Ggx  
{ Cu7iHhY5  
sSiteURL= sURL; GTvb^+6  
sFilePath = sPath; ]x\wP7x  
sFileName = sName; nQ6'yd"  
this.nSplitter = nSpiltter; 2kve?/  
1vb0G;a;|  
~?r6Ax-R  
} \/Y<.#?_  
uuB\~ #?T  
\O~P !`  
public String getSSiteURL() `#bcoK5  
{ ma~`&\xE  
return sSiteURL; ZC-
N4ESr  
} 2{N0. |5  
v0sX'>f  
X}Fv*  
public void setSSiteURL(String value) *PPFk.#x  
{ x.RZ!V-  
sSiteURL = value; yAe}O#dy  
} 'l;|t"R12  
@pz2}Hd|  
&I=q%  
public String getSFilePath() )M~5F,)  
{ ?`$4ZDM  
return sFilePath; |Gi/=[Tp  
} 7;{F"/A  
gy.; "W  
7Jk.U=vY  
public void setSFilePath(String value) {`> x"Y5  
{ _6(=0::x  
sFilePath = value; -6\9B>qa  
} kE}?"<l  
xuF_^  
%LyB~X  
public String getSFileName() V ALYA=w/  
{ [<hiOB  
return sFileName; ^M"g5+q  
} RP$A"<goP  
cW\7yZh  
(%1*<6ka  
public void setSFileName(String value) *:(t.iL  
{ $fKWB5p|()  
sFileName = value; lk|/N^8M  
} 4M}/PoJ  
<:w7^m  
zF
IbCv8  
public int getNSplitter() (WC<XKf  
{ M-_)CR  
return nSplitter; sr4K-|@  
} ORNE>6J H  
t
p"
\  
e_SlM=_u  
public void setNSplitter(int nCount) _+i-)  
{ l_WY];a  
nSplitter = nCount; 7VraWW`H'  
} V#gXchH[L  
} tH(Z9\L7  
O?_'6T  
qyto`n7  
/* FB""^IC?W  
**Utility.java G>j/d7  
*/ vs+N{ V  
package NetFox; W+vm!7wX0  
iBQftq7  
O1A*-G:X  
public class Utility { i~4Kek6,I  
S1."2AxO  
s*;~CH-[  
public Utility()
8}&cE#@  
{ eF9LZ"-s  
O`eNuQSv  
v-o/zud]]  
} m(Oup=\%b}  
#AHIlUH"m  
//线程睡眠 +_<#8v  
public static void sleep(int nSecond) zI(Pti  
{ Z'E@sc 9  
try{ 9
iUw7-)  
Thread.sleep(nSecond); Uvp?HZ\Z  
} `&o|=  
catch(Exception e) GC~::m~  
{ h W-[omr0  
e.printStackTrace (); P VPwYmte  
} m~v Ie c  
}
EpiagCS  
xnArYm  
//日志 /cg!Ap5  
public static void log(String sMsg) /Wa+mp  
{ V
:lDR20*\  
System.err.println(sMsg); >v(Xc/oI
 
} ^0 t`EZ$  
m$kmoY/  
6-oQs?  
public static void log(int sMsg) ` H"5nQRV  
{ NQb?&.C   
System.err.println(sMsg); 8/=2N  
} L.5GX 29  
} c;WS !.  
w v1R
]3}  
TS-[
p d  
/* ."2V:;;  
**TestMethod.java .]" o-(gB  
*/ )}EwEM  
package NetFox; 87-oR}/r  
Y=5hm  
rkD(KG9E  
public class TestMethod { %Z.!Bm:  
EV}%D9:  
Xd4~N:  
public TestMethod() N.fIg  
{ ///xx/weblogic60b2_win.exe uaS?y1:c  
try{ V{8mx70  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); DP?gozm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Zy<0'k%U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cD 1p5U  
fileFetch.start(); $HaM, Oh;i  
}  z\\MLyS  
catch(Exception e){e.printStackTrace ();} b_B4  
L U7.  
KMZ% 1=a  
} S_)va#b#  
Dx8^V
%b  
y(%6?a @  
public static void main(String[] args) <fP|<>s$@1  
{ J9o]$.e  
new TestMethod(); ]WS 7l@  
} {P*RA'H3G  
} u+-}|  
点击下载更多相关资料