http断点续传简单实现（java)

/* ,f~)CXNT?  
**SiteFileFetch.java NC3XJ 4  
*/ bg2r  
package NetFox; vt#&YXu{A  
import java.io.*; m 0]1(\%  
import java.net.*; Am<){&XT ]  
qzWnl[3  
6?';ip  
public class SiteFileFetch extends Thread { 8&:dzS  
V#+M lN  
_D{{C  
SiteInfoBean siteInfoBean = null; //文件信息Bean %_(^BZd  
long[] nStartPos; //开始位置 _xM}*_<VP  
long[] nEndPos; //结束位置 Lh-+i  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Tdxc%'l  
long nFileLength; //文件长度 )`#SMLMy~  
boolean bFirst = true; //是否第一次取文件 m'KEN<)s  
boolean bStop = false; //停止标志 ll ^I;o0  
File tmpFile; //文件下载的临时信息 g*WY kv  
DataOutputStream output; //输出到文件的输出流 *|
,ye5"  
lQL/I[}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） B$G9#G6pZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4|hfzCjMI  
{ 7g4IAsoD  
siteInfoBean = bean; ~X-v@a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |[@v+koq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U9XOs)^  
if(tmpFile.exists ()) 0pBG^I`_  
{ CN6b982&  
bFirst = false; ;?{OX  
read_nPos(); cS>xT cj  
} C_ W%]8u  
else }-@h H(  
{ fM3ZoH/  
nStartPos = new long[bean.getNSplitter()]; w x,gth*p  
nEndPos = new long[bean.getNSplitter()]; R=C+]  
} "d*-
k R  
brdY97s4  
n],"!>=+  
@Ll^ze&HI  
} \98|.EG  
{tuGkRY2~  
UAds$9  
public void run() hM[I}$M&O  
{ JD~]aoH  
//获得文件长度 KkSv23In  
//分割文件 #;\tgUQ  
//实例FileSplitterFetch (/|f6_9!  
//启动FileSplitterFetch线程 $*7AG  
//等待子线程返回 AQs_(L
R  
try{ Aj+0R?9tG  
if(bFirst) |iVw7M:  
{ RCMO?CBe  
nFileLength = getFileSize(); {'o\#4Wk  
if(nFileLength == -1) <$8e;:#:  
{ 6z5?9I4[  
System.err.println("File Length is not known!"); t.]e8=dE  
} m</nOf+C  
else if(nFileLength == -2) 51puR8AG>  
{ G}`Hu_ [\)  
System.err.println("File is not access!");  KRh?{  
} B0!W=T\  
else +|Mi lwr  
{ mg *kB:p  
for(int i=0;i<nStartPos.length;i++) }#E~XlX^  
{ .*L_*}tno  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); G=>LW1E|  
} h|.*V$3  
for(int i=0;i<nEndPos.length-1;i++) 0GnbE2&  
{ BoXGoFn  
nEndPos = nStartPos[i+1]; Jek)`D  
} ^qPS&G  
nEndPos[nEndPos.length-1] = nFileLength; Ok_)C+o  
} rY(^6[!  
} \E,Fe:/g  
#}zL?s^G  
{pEbi)CF,}  
//启动子线程 K[i|OZWu  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nNcmL/
(  
for(int i=0;i<nStartPos.length;i++) / Hexv#3  
{ zbP#y~[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /N`E4bKBR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !S[7IBk%  
nStartPos,nEndPos,i); sme!!+Rd  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S)*!jI  
fileSplitterFetch.start(); |I=\+
P}s  
} +FYhDB~m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), QfsTUAfR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e[J0+ x#;r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {1]Of'x'  
nEndPos = " + nFileLength); ZTP&*+d  
// fileSplitterFetch[nPos.length-1].start(); ch]Q%M  
A[X~:p.^G  
2bt2h.a  
//等待子线程结束 c>e~$b8  
//int count = 0; qEB]Tj e[  
//是否结束while循环 .\b# 0w  
boolean breakWhile = false; \S"YLRn"  

9h 0^_|"  
( O/+.qb  
while(!bStop) `xd{0EvF  
{ h
h"=|c  
write_nPos(); P6o-H$ a+  
Utility.sleep(500); IQCIc@5  
breakWhile = true; 6WX+p3Kv  
@d=4C{g%o  
@@Vf"o+S  
for(int i=0;i<nStartPos.length;i++) U)grC8 C  
{ *dm?,~f%<  
if(!fileSplitterFetch.bDownOver) C6(WnO{6  
{ i3 n0W1~  
breakWhile = false; 2j7e@p
r  
break; 6GtXM3qtS  
} qlfYX8edZ  
} XxEKv=_bc  
if(breakWhile) LVp*YOq7  
break; $@:z4S(  
7nL3+Pq  
X?Mc"M  
//count++; bol#[_~  
//if(count>4) C/x<_VJzN/  
// siteStop(); x?MSHOia`P  
} y~pJ|E  
Mlr}v^"G  
@AU<'?k  
System.err.println("文件下载结束！"); ~#jD/  
} wH Q$F(by  
catch(Exception e){e.printStackTrace ();} e(m#elX  
} = A;B-_c  
zg83->[  
pg'3j3JW$  
//获得文件长度 yp:_W@  
public long getFileSize() ONw;NaE,  
{ t
J,x>s?Y  
int nFileLength = -1; ?4i:$.A Y  
try{ pC'GKk 8  
URL url = new URL(siteInfoBean.getSSiteURL()); =D2x@ank[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); < l%3P6|  
httpConnection.setRequestProperty("User-Agent","NetFox"); x0!5z1KQh  
YaDr.?  
$!_]mz6*  
int responseCode=httpConnection.getResponseCode(); \#; -C<[b  
if(responseCode>=400) (S[" ak  
{ r*!sA5  
processErrorCode(responseCode); T7{Z0-  
return -2; //-2 represent access is error .<C}/Cl  
} *n=NBkq%/!  
xW;-=Q  
j7)Xm,wI8  
String sHeader; 2So7fZa^wg  
9ZEF%&58Y  
//}[(9b'\  
for(int i=1;;i++) /U#{6zeM[,  
{ 1>SCY_Cv  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~"+Fp&[9f  
//Utility.log(in.readLine()); 9\]%N;;Lo  
sHeader=httpConnection.getHeaderFieldKey(i); -  zQ  
if(sHeader!=null) . 787+J?  
{ wcT0XXh  
if(sHeader.equals("Content-Length")) {^xp?zpV  
{ =-c"~
4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >}*iQq  
break; 6/Coi,om  
} &1DU]|RoT&  
} e'c~;Z\A
 
else FN&.PdRT  
break; Q4_+3-g<7L  
} 0 pHqNlb  
} OwwlQp ~!J  
catch(IOException e){e.printStackTrace ();} EQkv&k5X  
catch(Exception e){e.printStackTrace ();} E(e'qL  
iG1vy'J#o  
1YA_`_@w  
Utility.log(nFileLength); O0{M3-  
y
#3mc#)k  
?[\(i)]  
return nFileLength; M<,E[2op  
} D 5qCn^R  
`R]9+_"N  
s wdW70  
//保存下载信息（文件指针位置） rZDlPp>BPZ  
private void write_nPos() %/:{x()G  
{  @t  
try{ DdTTWp/  
output = new DataOutputStream(new FileOutputStream(tmpFile)); mlR*S<Z  
output.writeInt(nStartPos.length); !TRJsL8  
for(int i=0;i<nStartPos.length;i++) tVZjtGz=  
{ xFpMn}CD  
// output.writeLong(nPos); ;2vHdN  
output.writeLong(fileSplitterFetch.nStartPos); `um#}ify#  
output.writeLong(fileSplitterFetch.nEndPos); LX
e{  
} )jK"\'cK  
output.close(); 38dXfl  
} ?#^_yd|<  
catch(IOException e){e.printStackTrace ();} Z4Nl{ 6  
catch(Exception e){e.printStackTrace ();} k=<,A'y-/  
} \d0R&vFHQ  
d*Y&V$?zl  
"qRE1j@%a  
//读取保存的下载信息（文件指针位置） >ln%3=  
private void read_nPos() 9d4PH  
{ v?)-KtX|  
try{ )g:\N8AZK  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y?2I /  
int nCount = input.readInt(); M`ETH8Su=  
nStartPos = new long[nCount]; 4}{HRs?  
nEndPos = new long[nCount]; SLL%XF~/Sb  
for(int i=0;i<nStartPos.length;i++) q@ >s#  
{ jd$uOn.r  
nStartPos = input.readLong(); [ds:LQq)/  
nEndPos = input.readLong(); a[:0<Ek  
} d*=P8QwL|  
input.close(); /lSz8h2  
} -y{o@  
catch(IOException e){e.printStackTrace ();} |~bl%g8xP  
catch(Exception e){e.printStackTrace ();} 8kw`=wSH>  
} [Z484dS`_  
s#ijpc>h  
Z;bzp3v  
private void processErrorCode(int nErrorCode) =N`"%T@=  
{ ]&1Kz 2/  
System.err.println("Error Code : " + nErrorCode); 3~\mP\/4v  
} \iAkF`OC  
EZz Ox(g  
@<e+E"6  
//停止文件下载 aE6I|6W
?  
public void siteStop() =yiR
B?  
{ 2JZf@x+}  
bStop = true; ;}{%|UAsx  
for(int i=0;i<nStartPos.length;i++) V?v,q'? $  
fileSplitterFetch.splitterStop(); K*Zf^g m  
#CoJ S[t  
%^m6Q!
  
} 2H_|Attoi  
} >[=q9k  
//负责部分文件的抓取 NIeT.!  
**FileSplitterFetch.java 5 fjeBfy  
*/ _*1/4^  
package NetFox; w{Wz^=';  
xR2E? 0T  
a&~d,vC  
import java.io.*; Y25S:XHk9  
import java.net.*; p5c^dC{  
@@7<L  
@CU3V+  
public class FileSplitterFetch extends Thread { _niXl&C  
OWFLw  

pq7G[  
String sURL; //File URL A^2VH$j]+  
long nStartPos; //File Snippet Start Position "W;GvI  
long nEndPos; //File Snippet End Position U[=VW0  
int nThreadID; //Thread's ID _h!OGLec  
boolean bDownOver = false; //Downing is over /c~z(wv  
boolean bStop = false; //Stop identical 7wsn8_n9  
FileAccessI fileAccessI = null; //File Access interface *,~d!Fc  
S1&mY'c  
_6&x$*O  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ozF>2`K }  
{ q-gN0"z^6$  
this.sURL = sURL; bR6.Xdt.n  
this.nStartPos = nStart; ps"DL4*  
this.nEndPos = nEnd; N;7Xt9l  
nThreadID = id; Y~vI@$<~(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8[U1{s:J  
} 3>%rm%ffE  
wQ qI@  
{,tEe'H7  
public void run() n5A0
E2!  
{ 0'`>20Y  
while(nStartPos < nEndPos && !bStop) )f9f_^;  
{ X>j% y7v  
hm>JBc:n-  
`uy)][j-  
try{ ,qV8(`y_  
URL url = new URL(sURL); f8kPbpV,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .{x-A{l  
httpConnection.setRequestProperty("User-Agent","NetFox"); -`gqA%#+  
String sProperty = "bytes="+nStartPos+"-"; Ub*Gv(Pg  
httpConnection.setRequestProperty("RANGE",sProperty); zE5%l`@|o  
Utility.log(sProperty);  XeDiiI
 
Vu0jNKUV  
Ro$'|}(+A  
InputStream input = httpConnection.getInputStream(); 4G0Er?D   
//logResponseHead(httpConnection); =4uL1[0'  
*Hy-D</w%  
%mPIr4$Pg  
byte[] b = new byte[1024]; '9%72yG  
int nRead; U7O~ch[,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Bs(\e^}  
{ m!5P5U x  
nStartPos += fileAccessI.write(b,0,nRead); 6U6,Wu  
//if(nThreadID == 1) YU.aZdA&V3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "l vPge  
} ciVN-;vi  
}z1aKa9  
Y&KI/]ly,L  
Utility.log("Thread " + nThreadID + " is over!"); 3JM0 m (  
bDownOver = true; UVlD]oXKh  
//nPos = fileAccessI.write (b,0,nRead); xGTVC=q  
} ]#;;)K}>  
catch(Exception e){e.printStackTrace ();} Esvr~)Y  
} ;<d("Yz:@Z  
} *ndXZ64  
TJ8IYo| D  
6gV-u~j[#  
//打印回应的头信息 2apR7  
public void logResponseHead(HttpURLConnection con) j'FSd*5m  
{ p'fq&a+  
for(int i=1;;i++) <7R\
#  
{ A ><  
String header=con.getHeaderFieldKey(i); u8L%R[#o  
if(header!=null) P2pdXNV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); hRTw8-wy:  
Utility.log(header+" : "+con.getHeaderField(header)); w%R(*,r6  
else
J7q^4M+o:  
break; @igr~hJ  
} .Nz2K[  
} fVx<f.xuW  
o^FlQy\  
U;u
@\E@2  
public void splitterStop() ~kPHf_B;z  
{ ]W39HL  
bStop = true; $q,2VH:Ip  
} -qaJ@T+J+7  
5H#f;L\k  
*Z\B9mx  
} U8Z(=*Z3  
#'[4k:  
=aZgq99  
/* N,fEta6  
**FileAccess.java &7_xr.c7  
*//文件访问(定位，写) &SuWmtq  
package NetFox;
_Y@vO  
import java.io.*; W5 ^eCYHoi  
%^tKt  
/ap3>xkt  
public class FileAccessI implements Serializable{ ){^o"A?-:  
,]RMa\Q4Wg  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fNe9as  
RandomAccessFile oSavedFile; .anXsjD%W  
long nPos; zLEl/yPE  
=p~k5k4  
tb36c<U-  
public FileAccessI() throws IOException \6AYx[|  
{ hB/4.K]8  
this("",0); a!rU+hiC  
} __N< B5E  
VbX+`CwH  
2GeJ\1k  
public FileAccessI(String sName,long nPos) throws IOException art L  
{ LkYcAY$w  
oSavedFile = new RandomAccessFile(sName,"rw"); |j:"n3~6  
this.nPos = nPos; }2c)UQD8  
oSavedFile.seek(nPos); WjLy7&  
} :"QR;O@  
F6XrJ?JM  
7[=*#7}.  
public synchronized int write(byte[] b,int nStart,int nLen) e$kBpG"D  
{ c"HB7  
int n = -1; 'w//d $+G_  
try{ <% #Dwo}  
oSavedFile.write(b,nStart,nLen); xVYy`_|  
n = nLen; F[am2[/<A  
} NMJX `  
catch(IOException e) w]<V~
X  
{ V$w
W?+V  
e.printStackTrace (); 2OT RP4U  
} CVUA7eG+  
]mIcK  
8i$quHd&x  
return n; i/U
Dda"E  
} J:W|2U="  
E%Tpby}^'  
 W^dk:  
} })#VO-J  
T($d3Nn1  
4mHR+SZy  
/* V9KI?}q:W  
**SiteInfoBean.java 5PF?Eq  
*/ 0PdeK'7  
package NetFox; E3..$x-/  
_A]8l52pt  
7Yv1et |  
public class SiteInfoBean { rgq~lZ.U4K  
Qc4r?7S<  
.+ezcG4q  
private String sSiteURL; //Site's URL Oly"ll*K  
private String sFilePath; //Saved File's Path  Y7*8A,  
private String sFileName; //Saved File's Name 6gfn5G  
private int nSplitter; //Count of Splited Downloading File =n@"lY u[  
)ZZjuFQJ)  
wPr9N}rf  
public SiteInfoBean() Ygeg[S!7  
{//nSplitter的缺省值为5 8M6 Xd]{%  
//default value of nSplitter is 5 8Dy5g  
this("","","",5); B'NtG84  
} 5;v_?M!UCK  
M[eq)a$  
3{:AG,G  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Y5mQY5u|  
{ dw*PjIB9x  
sSiteURL= sURL; UTWchh  
sFilePath = sPath; Tumv0=q4wd  
sFileName = sName; "mk@p=d  
this.nSplitter = nSpiltter; DtEvt+h  
6DkFIkS  
*sJT\J$D[  
} gWk?g^KJL  
0Y>5&  
ZYS`M?Au  
public String getSSiteURL() bm>N~DC  
{ {UeS_O>(  
return sSiteURL; lIhP\:;S&  
} g49G7sk  
!l6Ez_'  
W(4Mvd  
public void setSSiteURL(String value) y -6{>P/  
{ k2 _i;v  
sSiteURL = value; o:wI{?%-3  
} [,bra8f[C  
;OMR5KAz  
@GVONluyU`  
public String getSFilePath() 6y+_x'  
{ hr@kU x  
return sFilePath; $.+_f,tU  
} kuq&8f~!  
r5,V-5b  
~:JoKm`vU  
public void setSFilePath(String value) ?<
;9=l\Q
 
{ QjlQsN!  
sFilePath = value; 8l.bT|#O  
} ApD`i+Y@  
!jQj1QZR`  
G'
U! #  
public String getSFileName() V?L8BRnV  
{ \V(w=  
return sFileName; ""f'L,`{.  
} P:#KBF;a  
Wa
5B;X~  
eS: 8Pn  
public void setSFileName(String value) +dG3/vV  
{ Hk8lHja+\  
sFileName = value; JW},7Ox  
} ?S<`*O +  
MvKr~  
=vs]Kmm  
public int getNSplitter() 
/2f
  
{ RVN;j4uMg  
return nSplitter; >d3`\(v-  
} WR"?j9y_q  
B"Ma<"HU  
1j*E/L  
public void setNSplitter(int nCount) y3 "+4e  
{ 5La' I7q  
nSplitter = nCount; `nCVO;B  
} O#@G .~n?  
} :Ahw{z`H#  
9u;/l#?@T  
aizJ&7(>  
/* 6}cN7wnm j  
**Utility.java OQ&'3hv{  
*/ `N}aV
Ns  
package NetFox; PX- PVW  
~@\sN+VS  
|SfCuV#g/<  
public class Utility { 7_Op(C4,nC  
.3'U(U  
oLS/  
public Utility() [gDl<6
a#4  
{ t-i\gq^  
gX|We}H  
ri/CLq^D  
} dw>1Ut{"3  
P:>]a$Is  
//线程睡眠 bo-L|R&O  
public static void sleep(int nSecond) n_{az{~  
{ y 2C Jk~  
try{ K=Z.<f  
Thread.sleep(nSecond); t2(vtxrt  
} 5c\dm  
catch(Exception e) `]=0oDG:1!  
{ 1)#dgsa  
e.printStackTrace (); b~*CJ8Ad  
} G ?Hx"3:?  
} [Y4Wm?  
3wMnTT"At  
//日志 4(dgunP  
public static void log(String sMsg) (h|E@gRa  
{ &;naaV_2T  
System.err.println(sMsg); 5]*!N  
} fZp3g%u  
v
?YxF}  
X4<Y5?&0  
public static void log(int sMsg) C~IE_E&Q`  
{ 8},:  
System.err.println(sMsg); Pj1k?7  
} =gB8(1g8  
} F/cA tT.M?  
:Y|[
?;  
W9QVfe#s  
/* w6h*dh$w  
**TestMethod.java 2;K2|G7  
*/ 3RF`F i  
package NetFox; J@OK"%12  
#5=
W[+4eN  
p<<dj%  
public class TestMethod { {rwT
4]4  
6ZAZJn|  
(^"2"[?a  
public TestMethod() XE]"RD<z  
{ ///xx/weblogic60b2_win.exe L&d.&,CNs'  
try{ P;eXUF+jn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); m8V
}E&6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Q_Wg4n5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `2/V.REX$h  
fileFetch.start(); yJ="dEn>i"  
} dZox;_b  
catch(Exception e){e.printStackTrace ();} {:|b,ep T  
TPs ]n7]:  
"|Kag|(qB  
} m@UrFPZ  
^#XQ2UN  
k?rJGc G  
public static void main(String[] args) ]:;dJc'  
{ \XO'7bNu-  
new TestMethod(); &;sW4jnt  
} ~6K.5t7  
} R9(Yi<CC  
点击下载更多相关资料