http断点续传简单实现（java)

/* MtC\kTW  
**SiteFileFetch.java g$s"x r`:  
*/ Z@fMU2e=Z  
package NetFox; 2xvTijO0  
import java.io.*; Jg=[!j0(  
import java.net.*; {-IH?!&v  
5BCHWX*y  
12;"=9e!  
public class SiteFileFetch extends Thread { ^>02,X mk  
)Xxu-/-  
!6:kJL}U  
SiteInfoBean siteInfoBean = null; //文件信息Bean GU'/-6-T  
long[] nStartPos; //开始位置 LutP&Ebt8  
long[] nEndPos; //结束位置 "ewSh<t
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Fyy)665x/  
long nFileLength; //文件长度 V|3}~(5=  
boolean bFirst = true; //是否第一次取文件 !6hUTjhW7z  
boolean bStop = false; //停止标志 O,"4HZG  
File tmpFile; //文件下载的临时信息 ( /{Wu:e  
DataOutputStream output; //输出到文件的输出流 hER]%)#r  
p9k'.H^:_  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） I/D(gY06<  
public SiteFileFetch(SiteInfoBean bean) throws IOException _|`
~CLE[  
{ ,)3%@MwO  
siteInfoBean = bean; ]NS{q85  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lAU`7uE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); wP.b2X_V  
if(tmpFile.exists ()) }p 0\  
{ HV@C@wmg  
bFirst = false; B2QttcJ  
read_nPos(); d 6 t#4!  
} ?yop#tjCbY  
else rf_(pp)  
{ fB+4mEG@  
nStartPos = new long[bean.getNSplitter()]; (055>D6  
nEndPos = new long[bean.getNSplitter()]; <&:OSd:%  
} Zq7Y('=`t@  
};"-6e/9  
-J8&!S8X  
!t/I j~o  
} {/SUfXq  
5[3vup?  
e E:J  
public void run() WPT0=Hqp7  
{ R&Y+x;({  
//获得文件长度 ._j9^Ll  
//分割文件 k@MAi*  
//实例FileSplitterFetch x"q!=&>f  
//启动FileSplitterFetch线程 Z _W.
iBF  
//等待子线程返回 9<BC6M_/  
try{ P%MYr"<$E  
if(bFirst) JGl0 (i*|  
{ ha+)ZF  
nFileLength = getFileSize(); W8{g<. /  
if(nFileLength == -1) z\wY3pIr2  
{ EM9K^l`  
System.err.println("File Length is not known!");
wp7<0PP  
} J{fTx@?(  
else if(nFileLength == -2) 7.Df2_)  
{ G^E"#F  
System.err.println("File is not access!"); Kx,#Wg{H  
} !Au'WJfE  
else [?z`XY_-  
{ ~JhH ,E  
for(int i=0;i<nStartPos.length;i++) ASA ]7qyO  
{ IiW*'0H:/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~n9x ,  
} Aw#@}TGT  
for(int i=0;i<nEndPos.length-1;i++) c'#w 8V  
{ }ZaZPB/_}P  
nEndPos = nStartPos[i+1]; /BEE.`6yI5  
} -JgN$Sf  
nEndPos[nEndPos.length-1] = nFileLength; 1.
29%O8V_  
} L-. +yNX)  
} r6_g/7.-  
-\=s+n_ZP?  
F/33# U  
//启动子线程 VZhtx)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )Iu0MN&  
for(int i=0;i<nStartPos.length;i++) !4Q0   
{ kucH=96  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
r{oRN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *?Hc8y-dG,  
nStartPos,nEndPos,i); aY:u-1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5dwC~vn}c  
fileSplitterFetch.start(); Lg6;FbY?  
} haNi[|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2>`m1q:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); cg`bbZ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h"O4r8G}  
nEndPos = " + nFileLength); >JOEp0J  
// fileSplitterFetch[nPos.length-1].start(); ,j3Yvn W  
>~_oSC)E
 
j_]#Ew\q  
//等待子线程结束 r xlKoa  
//int count = 0; GnTCq_\  
//是否结束while循环 Ow
d{;  
boolean breakWhile = false; _#;UXAi  
M/<>'%sj  
Zw@=WW[Q`p  
while(!bStop) ,u.G6"<  
{ 6l Suzu  
write_nPos(); Rda~Drz  
Utility.sleep(500); pAdx 6  
breakWhile = true; Twq/Y07M  
V.\12P  
/O`<?aP%  
for(int i=0;i<nStartPos.length;i++) MgpjC`  
{ GN0s`'#"3%  
if(!fileSplitterFetch.bDownOver) 3.0t5F<B  
{ pUV4oyGV   
breakWhile = false; fX:=_c   
break; Pi/V3D)B  
} >~+qU&'2  
} $X\deJ1Hi  
if(breakWhile) ]7|Z
s]6  
break; )\O;Rt(  
kg/<<RO  
n,Gvgf  
//count++; 8%\0v?a5  
//if(count>4) p)&Yr  
// siteStop(); 8bTE#2+-  
} vyS8yJUY  
b
+/z,c6w  
PNgdWf3  
System.err.println("文件下载结束！"); 1\u{1 V  
} A WS[e$Mt2  
catch(Exception e){e.printStackTrace ();} ;rj|>  
} W]B75  
[H4)p ,R  
_GW,9s^A  
//获得文件长度 tDWoQ&z2t_  
public long getFileSize() FTJvkcc?m  
{ UI]UxEJ  
int nFileLength = -1; BmhIKXE{*  
try{ _48@o^{  
URL url = new URL(siteInfoBean.getSSiteURL()); YP4lizs.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zm~sq_=^  
httpConnection.setRequestProperty("User-Agent","NetFox"); %mFZ!(  
x?6 \C-i  
S4O'N x  
int responseCode=httpConnection.getResponseCode(); H$M{thW  
if(responseCode>=400) BJ*8mKi h  
{ 1`q>*S](  
processErrorCode(responseCode); >{1 i8 b@  
return -2; //-2 represent access is error SoJ=[5W  
} (8Inf_59  
EK8rV  
k1_"}B5  
String sHeader; YQ$Wif:@(n  
eeM$c`Y<  
YiGSFg  
for(int i=1;;i++) LW#
$%}  
{ A7enC,Ey  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^| r6>b  
//Utility.log(in.readLine()); Eb~e=){  
sHeader=httpConnection.getHeaderFieldKey(i); {lO>i&mx  
if(sHeader!=null) XF Cwa  
{ hd%O\D?  
if(sHeader.equals("Content-Length")) cOoF +hz0O  
{ H"b}lf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); crlCN  
break; 9D`p2cO  
} YZ(tjIgQ  
} aH'=k?Of;  
else qBDhCE  
break; .~Gt=F+`s  
} 
}}X<e  
} N@x5h8  
catch(IOException e){e.printStackTrace ();} :p
w6#yi8`  
catch(Exception e){e.printStackTrace ();} /r?EY&9G  
q/eod  
tO~o-R  
Utility.log(nFileLength); MZWicfUy  
c`s ]ciC  
Dd'4W  
return nFileLength; lU8X{SV!  
} 2qDyb]9  
bH`r=@.:cu  
:=oIvSnh  
//保存下载信息（文件指针位置） XY)I~6$Y  
private void write_nPos() IfzW%UL  
{ Sau?Y  
try{ [J\! 2\Oo  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j`l'Mg  
output.writeInt(nStartPos.length); <tI_
u ~P  
for(int i=0;i<nStartPos.length;i++) ;y]BXW&l&  
{ =2OLyZDI  
// output.writeLong(nPos); ,8&ND864v  
output.writeLong(fileSplitterFetch.nStartPos); #!7b3>}  
output.writeLong(fileSplitterFetch.nEndPos); 5J2tR6u-(  
} <!a%GI  
output.close(); _%@ri]u{ov  
} &:[hUn8jU  
catch(IOException e){e.printStackTrace ();} Wu@v%!0  
catch(Exception e){e.printStackTrace ();} @p[ml m  
} %T,cR>lw  
tdOox87YK  
COFCa&m9c  
//读取保存的下载信息（文件指针位置） r 3FUddF'  
private void read_nPos() qk_YFR?R  
{ ['_W<  
try{ #4Ltw,b^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H
$!sK  
int nCount = input.readInt(); P.W@5:sD  
nStartPos = new long[nCount]; V2o1~R~  
nEndPos = new long[nCount]; 3FsX3K,_X  
for(int i=0;i<nStartPos.length;i++) F-GrQd:O=  
{ "VgPaz
#  
nStartPos = input.readLong(); 1qE*M7_:E>  
nEndPos = input.readLong(); >p>B-m  
} ~yu\vqN  
input.close(); 2B[I- K s  
} 'tJ@+(tqw  
catch(IOException e){e.printStackTrace ();} HSlAm&Y\  
catch(Exception e){e.printStackTrace ();} I;UCKoFT  
} L8~zQV$h  
b@ OF  
bF c %  
private void processErrorCode(int nErrorCode) ve*m\DU  
{ fK10{>E1  
System.err.println("Error Code : " + nErrorCode); O)D+u@RhH  
} @WnW @'*F  
H:4?sR3  
Jk_}y  
//停止文件下载 .2x`Fj;o1  
public void siteStop() ueLdjASJ  
{ >vZ^D  
bStop = true; KA{JSi  
for(int i=0;i<nStartPos.length;i++) c;doxNd6  
fileSplitterFetch.splitterStop(); R=<uf:ca  
@2/xu  
y1t,i. [  
} {(_>A\zi  
}
5u
O.@0  
//负责部分文件的抓取 ]}d.h!`<)  
**FileSplitterFetch.java k[8{N  
*/ C7_nA:Rc  
package NetFox; |`Q2K9'4bL  
O>/&-Wk=  
-^WW7 g`  
import java.io.*; W3y9>]{x^  
import java.net.*; nRh.;G  
q4]Qvf>  

sG:tyvln  
public class FileSplitterFetch extends Thread { A ^X1  
Dz<vIMLF{  
Q)93+1]  
String sURL; //File URL W3]?>sLE*  
long nStartPos; //File Snippet Start Position N(Xg#m  
long nEndPos; //File Snippet End Position kA{eT  
int nThreadID; //Thread's ID 9k3RC}dEr  
boolean bDownOver = false; //Downing is over gi JjE  
boolean bStop = false; //Stop identical p&W{g$D>  
FileAccessI fileAccessI = null; //File Access interface f!13Ob<8r  
.Gn-`  
* %w8bB  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2'7)D}p  
{ UY/qI%#L#,  
this.sURL = sURL; _&K>fy3t&  
this.nStartPos = nStart; 2i~zAD'  
this.nEndPos = nEnd; [=& tN)_  
nThreadID = id; +J <<me4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4C`p`AQqpQ  
} DNGj81'c  
x?n13C  
+W^$my)<  
public void run() +.IncY8C$  
{ g%%j"Cz1  
while(nStartPos < nEndPos && !bStop) f6JC>Np  
{ oWV^o8& GH  
;[!W*8.c  
b =R9@!  
try{ 4nU+Wj?T  
URL url = new URL(sURL); \KkAU6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \><v1x>;  
httpConnection.setRequestProperty("User-Agent","NetFox"); e8Vt
KVcY  
String sProperty = "bytes="+nStartPos+"-"; gbjql+Mx+  
httpConnection.setRequestProperty("RANGE",sProperty); pXl*`[0X#  
Utility.log(sProperty); j[Oh>yG  
/<)kI(gf  
aJSBG|IC  
InputStream input = httpConnection.getInputStream(); 9 M!U@>  
//logResponseHead(httpConnection); ]Aa.=  
'I5~<"E  
<gjA(xT5  
byte[] b = new byte[1024]; v|GDPq  
int nRead; U{Moyj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4j}uVGi{e  
{ G&dz<f
 
nStartPos += fileAccessI.write(b,0,nRead); mE"},ksg  
//if(nThreadID == 1) k_](u91  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gp}}MGk  
} f<Xi/(  
Ue!~|:  
#Y<(7  
Utility.log("Thread " + nThreadID + " is over!"); TRku(w1f  
bDownOver = true; 2sYOO>  
//nPos = fileAccessI.write (b,0,nRead); DH'0#  
} u8Oo@xf0Fr  
catch(Exception e){e.printStackTrace ();} 9t_N9@  
} zi= gOm  
} $-"V 2  
'h{| ]  
:{M1]0NH  
//打印回应的头信息 ,]Q i/m  
public void logResponseHead(HttpURLConnection con) 2PG= T/  
{ Z=[?Tf  
for(int i=1;;i++) xOBzT&  
{ Y!fgc<]'&  
String header=con.getHeaderFieldKey(i); xL}~R7  
if(header!=null) A&7~]BR\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #ByrX\  
Utility.log(header+" : "+con.getHeaderField(header)); z-`-0@/A$  
else GCv*a[8?n  
break; EbMG9  
} TY*uK  
} @Xl/<S&  
V8+8?5'l  
wfrSI:+>  
public void splitterStop() D5jZ;z}  
{ o 12w
p  
bStop = true; aT20FEZ;  
} ;}QM#5Xdt  
Zmz
YJ$:6  
2pV@CT  
} ^^{7`X u  
*$v`5rP  
tP0!TkTo9  
/* hp!. P1b  
**FileAccess.java ]97`=,OUg  
*//文件访问(定位，写) @V71%D8{  
package NetFox; #/2W RN1L  
import java.io.*; XS`=8FQ  
3FhkK/@  
0mYKzJi  
public class FileAccessI implements Serializable{ jR@J1IR<  
H3Sfz'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P#N@W_""YD  
RandomAccessFile oSavedFile; P=PVOt@ b  
long nPos; VY_<c98v  
82A[[^`  
RZ GD5`n  
public FileAccessI() throws IOException $x|4cW2  
{ CvB)+>oa  
this("",0); X@up=
%(  
} U!Eo*?LU$  
0\
}%~e  
ODE^;:z !  
public FileAccessI(String sName,long nPos) throws IOException #Oq~ZV|<l  
{ hH*/[|z  
oSavedFile = new RandomAccessFile(sName,"rw"); *8#]3M]  
this.nPos = nPos; 3iv;4e ;  
oSavedFile.seek(nPos); {[$JiljD  
} 4I7;/ZgALQ  
EViQB.3w\  
>cRE$d?  
public synchronized int write(byte[] b,int nStart,int nLen) -A)XYz  
{ ;@lC08SE  
int n = -1; BY!M(X jrZ  
try{ M?m)<vMr*  
oSavedFile.write(b,nStart,nLen); .C?r
ToCY  
n = nLen; 9w08)2$Na  
} ^yp`<=  
catch(IOException e) i)mQ?Y#o  
{ \*.u(8~2o  
e.printStackTrace (); $zYo~5M?i-  
}  SED_^  
D?6ah=:&R  
V{+5Fas^l  
return n; >4x~US[VB  
} rWnZIt"  
U1~6o"1H  
+u]L#].;  
} gaa;PX  
#(f- cK  
@-H D9h  
/* SRBQ"X[M2  
**SiteInfoBean.java `8<h aU  
*/ Kta7xtu  
package NetFox; 4M{]YZMw8  
fkWTO"f-  
@l^BW*BCo  
public class SiteInfoBean { 6O# xV:Uc<  
qGH\3g-  
HI*j6H?\  
private String sSiteURL; //Site's URL $ ";NS6 1  
private String sFilePath; //Saved File's Path G@I/Dy  
private String sFileName; //Saved File's Name , \ 6*fXc  
private int nSplitter; //Count of Splited Downloading File KQv97#n1  
Ub9p&=]h  
04wO9L;  
public SiteInfoBean() BkcA_a:W  
{//nSplitter的缺省值为5 |*[#Iii'  
//default value of nSplitter is 5 ds|L'7  
this("","","",5); P K9BowlW  
} Ki{]5Rz  
'H.,S_v1x  
$9m>(b/;n  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?84B0K2Ns  
{ $TR#-q  
sSiteURL= sURL; V-.Nc#  
sFilePath = sPath; BjsF5~+\  
sFileName = sName; jpI=B  
this.nSplitter = nSpiltter; wrmbOT  
1Z| {3W  
gW(7jFl  
} 6<N Q/*(/  
nW7Ew<`Q  
/+{]?y,  
public String getSSiteURL() ]v6s](CE  
{ .Bb86Y=3  
return sSiteURL; |uRZT3bGyj  
} u{dI[?@  
bi 8Qbo4  
#V:28[  
public void setSSiteURL(String value) _8eN^oc%  
{ 9Vh>ty1|_  
sSiteURL = value; whdoG{/
  
} U9:w^t[Pp  
r"aJ&~8::W  
 Z?_t3  
public String getSFilePath()  Lkl+f~m  
{ q]r
?s%x  
return sFilePath; |E=8  
} TU(w>v  
g9K7_T #W  
i<uWLhgh1$  
public void setSFilePath(String value) SB}0u=5  
{ q{*4BL'  
sFilePath = value; 6}xFE]Df-Y  
} G"&yE.E5  
%\ef Mhn  
ghu8Eg,Y  
public String getSFileName() yB~`A>~M  
{ &hri4p/  
return sFileName; VvJ]*D+e  
} *4oj'}  
tH\ aHU[  
&Y/Myh[P  
public void setSFileName(String value) Fo86WP}  
{ nL]-]n;  
sFileName = value; @& vtY._  
} 2^.qKY@g@  
ZN]LJ4|xu  
{:m%n-  
public int getNSplitter() e6JT|>9A7  
{ rs?"pGz;  
return nSplitter; @M!WosRk  
} uv$t>_^  
? pkg1F7  
~Vf+@_G8`  
public void setNSplitter(int nCount) tbr1mw'G  
{ G*x"drP  
nSplitter = nCount; nC;2wQ6aO  
} X;D"}X4(E  
} "`''eV3  
9=wt9` ?  
j4hi
MI;  
/* ds9L4zfO  
**Utility.java +o94w^'^$b  
*/ Z F&aV?  
package NetFox; a&*fk?o  
$Z8=QlG>  
k@
i+gV%  
public class Utility { @=kDaPme92  
 {Hp*BE   
h;(#^+LH  
public Utility() M]JD(  
{ E)h&<{%  
}VUrn2@-4  
~c*$w O\  
} TDtS^(2A7K  
G6?+Qzr  
//线程睡眠 28N v'  
public static void sleep(int nSecond) a?]"|tQ'  
{ ;E{k+vkqy  
try{ j>KJgSs]&\  
Thread.sleep(nSecond); ]*M-8_D  
} qbwX*E~;  
catch(Exception e) ZI8*PX%2  
{ ;jEDGKLq  
e.printStackTrace (); B9glPcy}SS  
} `J(im  
} cGVIO"(VP  
|9X$@R  
//日志 X$<s@_
#1  
public static void log(String sMsg) nM?mdb  
{ HpD<NVu  
System.err.println(sMsg); jhN]1t/\X  
} :@H&v%h(u  
",hPy[k  
5[py{Gq  
public static void log(int sMsg) Qq.ht  
{ xpb,Nzwt^  
System.err.println(sMsg); NLz[F`I  
} E>}(r%B  
} F/ODV=J-  
PqOPRf  
{"([p L  
/* IJ`%Zh{f  
**TestMethod.java \UF/_'=K  
*/ rh6gB]X]3:  
package NetFox; 
oJLpFL  
2qF ?
%  
R2 I 7d'|v  
public class TestMethod { <Xsy{7  
{H5a.+-(bE  
~_ 8X%uty  
public TestMethod() S?M'JoYy  
{ ///xx/weblogic60b2_win.exe C" W,  
try{ b,8\i|*!f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `=zlS"dQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qkEre  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M!9gOAQP  
fileFetch.start(); U>,E]'  
} ka^sOC+Y  
catch(Exception e){e.printStackTrace ();} M'n2j  
122%KS  
8-2e4^ g(  
} yyj?hR@rZ  
41S.&-u  
{7%W/C#A  
public static void main(String[] args) DLWG0$#!  
{ srh>" 2."  
new TestMethod(); nI_43rG:Uf  
} sr=~Uq{g  
} gNsas:iGM  
点击下载更多相关资料