http断点续传简单实现（java)

/* bDl:,7;  
**SiteFileFetch.java
A?YYR%o%'  
*/ 3BMz{ny=  
package NetFox; Nc+0_|,  
import java.io.*; 5:@b
NNX'j  
import java.net.*; ?mH=3 :~  
ifn=De3+  
zhJeTctRz  
public class SiteFileFetch extends Thread { O nXo0PV/(  

o#m31*o  
{it.F4.  
SiteInfoBean siteInfoBean = null; //文件信息Bean D6ZHvY8R  
long[] nStartPos; //开始位置 MdBmq/[O  
long[] nEndPos; //结束位置 oG,>Pk
  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O,%UNjx9K  
long nFileLength; //文件长度 mE~WE+lw9  
boolean bFirst = true; //是否第一次取文件 y [Vd*8  
boolean bStop = false; //停止标志 +<E#_)}`D6  
File tmpFile; //文件下载的临时信息 P'~`2W0sz  
DataOutputStream output; //输出到文件的输出流 F,_L}  
f`qy~M&  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） v47' dC  
public SiteFileFetch(SiteInfoBean bean) throws IOException ".}R$W  
{ WuK<?1meN  
siteInfoBean = bean; V!:!c]8F  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8
\{!*?9!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ai 4k?  
if(tmpFile.exists ()) hDXTC_^s  
{ *;Kp"j  
bFirst = false; bm#5bhX\|  
read_nPos(); R}oN8
 
} 7C|AiSH  
else l!p`g>$&f  
{ S*l/ Sa@  
nStartPos = new long[bean.getNSplitter()]; lT[,w9$  
nEndPos = new long[bean.getNSplitter()]; ;@;aeu  
} ^wy  
jIKg*
@  
n@pwOHQn<|  
)G48,.
"  
} <)d%c%f'`  
"~Fg-{jM%  
SK}jhm"y  
public void run() ~(GvjB/C8  
{ *~8F.c
x  
//获得文件长度 O?vh]o  
//分割文件 X;LYGJ{Xk  
//实例FileSplitterFetch =z}PR1X!  
//启动FileSplitterFetch线程 GgxPpS<ne  
//等待子线程返回 Z=% j|xE_  
try{ ykQb;ZP8jh  
if(bFirst) ~<k>07  
{ "dpjxH=xO  
nFileLength = getFileSize(); )WvKRp r  
if(nFileLength == -1) CaYb}.:AX  
{ *(x.egOR
d  
System.err.println("File Length is not known!"); ^fF#Ej1  
} o@A`AA9  
else if(nFileLength == -2) M7BpOmK'  
{ c|<F8n  
System.err.println("File is not access!"); hNc8uV{r=  
} CVO_F=;  
else nf pO  
{ ,!> ~izB  
for(int i=0;i<nStartPos.length;i++) hk !=ZE3  
{ ;Am3eJa*-  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  ]]p\1G  
} *k(FbZ  
for(int i=0;i<nEndPos.length-1;i++) S$b)X"h  
{ 'bbw0aB4  
nEndPos = nStartPos[i+1]; bg~CV&]M  
} jwwRejNV  
nEndPos[nEndPos.length-1] = nFileLength; C).\ J !  
} @Z/jaAjUC  
} RZ
W=z}T+H  
J@>|`9T9$  
kw59`z Es  
//启动子线程 ,X/j6\VBO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -#I]/7^  
for(int i=0;i<nStartPos.length;i++) GkOk.9Y,5  
{ 7c_2.T@4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r2:{r`ocM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),
NFVu~t  
nStartPos,nEndPos,i); 10Eun }  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g:uVl;>  
fileSplitterFetch.start(); J *LPv9)  
} !$n@:W/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bofI0f}5.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "nr?WcA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;8[VCU:  
nEndPos = " + nFileLength); !$98U~L  
// fileSplitterFetch[nPos.length-1].start(); { {?-& yA  
w!UF^~  
!=S?*E +j)  
//等待子线程结束 `N[@lV\xp!  
//int count = 0; Op0*tj2i),  
//是否结束while循环 Um/l{:S  
boolean breakWhile = false; xy`Y7W=  
aUL7]'q}  
DWtITO>  
while(!bStop) M?8sy  
{ 3^KR{N p  
write_nPos(); v[|-`e*  
Utility.sleep(500); uWx<J3~q.  
breakWhile = true; YXo?(T..  
L%H\|>k`  
]6(%tU  
for(int i=0;i<nStartPos.length;i++) yoGG[l2k>s  
{ l|+$4 Nb2  
if(!fileSplitterFetch.bDownOver)
O+&;,R:  
{ $j,$O>V  
breakWhile = false; f5//?ek  
break; '-myOM7  
} 6}Y==GPt  
} nql1I<I  
if(breakWhile) -f
?  
break; e<+)IW:  
E3a^"V3p  
tRPIvq/  
//count++; sm"Rp~[i  
//if(count>4) HG /fp<[   
// siteStop(); -pJ\_u/&%`  
} :YLs]JI<  
,$!F,
c  
M2V`|19Q  
System.err.println("文件下载结束！"); <f (z\pi1  
} 2aTq?ZR|8A  
catch(Exception e){e.printStackTrace ();} J#:`'eEG  
} F u5zj\0J  
xVsI#`<a  
h% >ZN-K)  
//获得文件长度 #Ey_.4S  
public long getFileSize() ,fiV xnQ  
{ qJ5b;=  
int nFileLength = -1; ?o)?N8U  
try{ LV ]10v6  
URL url = new URL(siteInfoBean.getSSiteURL()); BZv:E?1z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t[;-gi,,  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5OPvy,e6  
zvGncjMkC  
#e=E  
int responseCode=httpConnection.getResponseCode(); 7 2i&-`&4  
if(responseCode>=400) 1 jLQij  
{ L_T+KaQCH  
processErrorCode(responseCode); |;:Kn*0/]  
return -2; //-2 represent access is error s5v}S'uO{  
} "%Ief4  
n?c[ E+i;  
#"oLz"{  
String sHeader; pFs/ipZX^*  
,2 xD>+=  
9b6U]z,  
for(int i=1;;i++) mph9/ %]S  
{ ^fN/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?*UWg[  
//Utility.log(in.readLine());
R`o Xkj  
sHeader=httpConnection.getHeaderFieldKey(i); @ o<OI  
if(sHeader!=null) [g`4$_9S  
{ %<+Ku11  
if(sHeader.equals("Content-Length")) _9"ZMUZ{  
{ L{1[:a)']B  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ` >>]$ZJ  
break; PDH|=meXM  
} Vx
o?%Dj  
} daCkjDGl\  
else Rt,po  
break; 3-AOB3](
 
} w('}QB`xad  
} Za?BpV~  
catch(IOException e){e.printStackTrace ();} >B``+Z^2  
catch(Exception e){e.printStackTrace ();} `*0VN(gf'  
'Hj([N  
fg,vTpBk  
Utility.log(nFileLength); <}.!G>X  
N,8.W"fV  
E|oOd<z  
return nFileLength; fHwS12SB  
} OK-*TPrc  
5{
!"}  
nxEC6Vh'  
//保存下载信息（文件指针位置） -ert42fN  
private void write_nPos() 2zbn8tO  
{ ./zzuKO8XK  
try{ L)<~0GcP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M%$ITE  
output.writeInt(nStartPos.length); <Vt"%C  
for(int i=0;i<nStartPos.length;i++) Myn51pczl  
{ Jw;G_dQ[  
// output.writeLong(nPos); eC<?g  
output.writeLong(fileSplitterFetch.nStartPos); S&&QU#  
output.writeLong(fileSplitterFetch.nEndPos); cb|hIn\>7  
} 1:yil9.\*  
output.close(); I\-M`^@  
} (i\{hq/  
catch(IOException e){e.printStackTrace ();} ?b}e0C-a  
catch(Exception e){e.printStackTrace ();} Z6-  
} YIIc@)  
ew,okRCN  
UHk)!P>  
//读取保存的下载信息（文件指针位置） cM,
g,E}  
private void read_nPos() `2\:b^h  
{ 7$Wbf4  
try{ ?MfwRWY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .qf~t/o  
int nCount = input.readInt(); 4\ElMb[]  
nStartPos = new long[nCount]; Z:<w
B#G  
nEndPos = new long[nCount]; n``9H91  
for(int i=0;i<nStartPos.length;i++) Z<=L  
{ ugj I$u  
nStartPos = input.readLong(); 2[1t )EW  
nEndPos = input.readLong(); F.@|-wq&  
} p1.3)=T  
input.close(); B7Zi|-F
  
} +~:OUR*>  
catch(IOException e){e.printStackTrace ();} b&Laxki  
catch(Exception e){e.printStackTrace ();} 2dB]Lw@s  
} -2u)orWP  
h3GUFiZ.  
L?M x"  
private void processErrorCode(int nErrorCode) e]dFNunFq0  
{ b?!S$Sxz  
System.err.println("Error Code : " + nErrorCode); +Y;hVcE9  
} <gFisc/#r  
&Cm]*$?  
"&
`>+Yw  
//停止文件下载 u(hJyo}  
public void siteStop() 1`s^r+11:  
{ GjN6Af~}  
bStop = true; 92C; a5s  
for(int i=0;i<nStartPos.length;i++) 9;
9ge  
fileSplitterFetch.splitterStop(); g HxR
w  
E{^W-  
k}qCkm27  
} sk:B;.z  
} 4hfq7kq7(  
//负责部分文件的抓取 zK_P3rLsS  
**FileSplitterFetch.java zTPNQ0=|  
*/ P0sAq7"  
package NetFox; .r-Zz3  
"j_cI-@6  
ZzQLbCV  
import java.io.*; ZCBF&.!  
import java.net.*; !&.-{ _$  
i6P$>8jBQ-  
3xdJ<Lrq  
public class FileSplitterFetch extends Thread { Q Wc^}#!!  
QUZ+#*:s  
\hEIQjfi  
String sURL; //File URL z yp3+|  
long nStartPos; //File Snippet Start Position iweT@P`  
long nEndPos; //File Snippet End Position A>mk0P)~Q  
int nThreadID; //Thread's ID Akws I@@  
boolean bDownOver = false; //Downing is over >lyE@S sA  
boolean bStop = false; //Stop identical #,1)@[  
FileAccessI fileAccessI = null; //File Access interface DSq?|H  
/?b{*<TK  
Jp^#G2  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y!rJ}e  
{ Hr7pcz/#l  
this.sURL = sURL; xpu2RE  
this.nStartPos = nStart; QoxQ
"r9Wh  
this.nEndPos = nEnd; q\gbjci  
nThreadID = id; 9:=:P>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]n"U])pJd  
} B&1E&Cv_8  
>#gDk K  
.N#KW  
public void run() vg"*%K$a  
{ p=kt+H&;  
while(nStartPos < nEndPos && !bStop) Y" rODk1  
{ PRFl%M.H`  
)iK:BL*Nw  
GZn=Hgv8  
try{ <$a-.C5  
URL url = new URL(sURL); Fq oh!F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4}UJBb?  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2|WM?V&  
String sProperty = "bytes="+nStartPos+"-"; fU$_5v4  
httpConnection.setRequestProperty("RANGE",sProperty); G+k wG)K  
Utility.log(sProperty); >LH}A6dUC  
&RI;!qn6(  
R9"}-A  
InputStream input = httpConnection.getInputStream(); ]$sb<o .a  
//logResponseHead(httpConnection); rKT.~ZP\  
">20`Mj8  
_%\%  
byte[] b = new byte[1024]; 6-g>(g  
int nRead; ]|=`-)AP3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) yx*<c#Uf  
{ ty4R2LnC  
nStartPos += fileAccessI.write(b,0,nRead); #N~1Ye  
//if(nThreadID == 1) Qgv g*KX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j+q)  
} cD)9EFo  
H5 :,hrZY  
WU@_aw[  
Utility.log("Thread " + nThreadID + " is over!"); c5 AaUza  
bDownOver = true; Q"c/]Sk)  
//nPos = fileAccessI.write (b,0,nRead); \i}-Y[Dg  
} Aho*E9VW  
catch(Exception e){e.printStackTrace ();} \DBEs02  
} fOdqr  
} }QQ 7jE  
`R7dn/  
X?&{< vz  
//打印回应的头信息 v]H9`s#,  
public void logResponseHead(HttpURLConnection con) '=\>n(%Q  
{ utl-#Wwt/  
for(int i=1;;i++) #sg dMrVQ  
{ "68X+!  
String header=con.getHeaderFieldKey(i); cu'(Hj  
if(header!=null) G)M! , Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o`7 Z<HF  
Utility.log(header+" : "+con.getHeaderField(header)); ' u;Zw%O(J  
else H!O
X1F  
break; :=5X)10
 
} EA9.?F  
} E`hR(UL ?  
HVhd#Q;  
UugR  
public void splitterStop() 'Nuy/\[{\  
{ P{:Zxli0  
bStop = true; w:iMrQeJg  
} r ?<kWR?w  
Gr)G-zE  
\&ZEIAe  
} ka ;=%*7T  
U /~uu  
SD:`l<l  
/* x*=m'IM[  
**FileAccess.java a^E>LJL  
*//文件访问(定位，写) F< 5kcu#iL  
package NetFox; ^6F, lS_t  
import java.io.*; z 0zB&}  
9ZatlI,
 
H+]h+K9\7  
public class FileAccessI implements Serializable{ 3/uvw>$  
L
Hu  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +Wy`X5v  
RandomAccessFile oSavedFile; |:4?K*w",  
long nPos; {D :WXvI  
DHuvHK0#  
i gjn9p&_  
public FileAccessI() throws IOException bb\XZ~)F  
{ 3 |LRb/|  
this("",0); :D;pDl  
} .3XiL=^~Qp  
n9k
  
*O@Zn  
public FileAccessI(String sName,long nPos) throws IOException Y6hV ;[\F  
{ wq!9wk9  
oSavedFile = new RandomAccessFile(sName,"rw"); $sg-P|Wo  
this.nPos = nPos; YWDgRb  
oSavedFile.seek(nPos); j8bA"r1  
} S~ S>62  
I>vU
;xV\m  
ggkz fg&  
public synchronized int write(byte[] b,int nStart,int nLen) u^c/1
H:6  
{ XeY[;}9  
int n = -1; {D|ST2:E  
try{ ;lrO?sm
 
oSavedFile.write(b,nStart,nLen); CR2.kuM0~  
n = nLen; G %\/[ B  
} H\E%.QIx  
catch(IOException e) E_[a|N"D  
{ |O'*CCrCL  
e.printStackTrace (); M"{*))O\-c  
} tq@)J_7|  
eY^zs0  
-%P}LaC<  
return n; <exyd6iI  
} >SziRm>Y7  
9=/4}!.  
=OV5DmVmQ  
} HINk&)FC  
\-{$IC-L  
7bRfkKD  
/* l,(:~KH|  
**SiteInfoBean.java 4}cxSl]jf!  
*/ E4Ez)IaKyi  
package NetFox; |;t{L^  
t0v>J9  
7r)]9_[(  
public class SiteInfoBean { !O}e)t  
9%3+\[s1  
Ie=gI+2  
private String sSiteURL; //Site's URL K"5q387!  
private String sFilePath; //Saved File's Path 61&{I>
~1  
private String sFileName; //Saved File's Name 7IkEud  
private int nSplitter; //Count of Splited Downloading File +oO7UWs>6  
$]}K;  
;#IrHR*Bk  
public SiteInfoBean() Fv$w:r]q6  
{//nSplitter的缺省值为5 Jg{K!P|i  
//default value of nSplitter is 5 Y"KJ`Rx  
this("","","",5); &b*v7c=o  
} ,,80nW9E  
_5(p=Zc  
"$K]+0ryG<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z1+Ewq3m  
{ O{7#Xj :_  
sSiteURL= sURL; 3vAP&i'I  
sFilePath = sPath; *b0z/6  
sFileName = sName; v,ni9DIu  
this.nSplitter = nSpiltter; O7LJ-M  
-b8SaLak  
VYh/URU>  
} $3&XM  
XkoPN]0n  
@(E6P;+{  
public String getSSiteURL() &2 *  
{
KHC F
z  
return sSiteURL; AW|SD  
}
t]]Ig  
0:4>rYBC  
_K'Y`w']  
public void setSSiteURL(String value) Oj_F1. r  
{ "*l{ m2"  
sSiteURL = value; -a~n_Z>_  
} ,D(Bg9C  

ePv`R'#  
\dE{[^.5  
public String getSFilePath() OK`^DIr5l  
{ )8}k.t>'s  
return sFilePath; |]?W`KN0  
}
fGs\R]  
sMUpkU-  
c~OPH 0,  
public void setSFilePath(String value) /kRCCs8t}  
{ 52Dgul  
sFilePath = value; 5A|dhw   
} #Hu##x|  
0YfmAF$/B  
kX}sDvP3  
public String getSFileName() QXL .4r%  
{ ggM~Chr  
return sFileName; h4h
p5M  
} {r|RH"|?Z(  
y\-iGKz{0  
#<sK3PT  
public void setSFileName(String value) !T ,=kh  
{ @.}Y'`9L  
sFileName = value; /%
p ~  
} _zzNF93Bn  
$""kZ  
#=ij</  
public int getNSplitter() 8No'8(dPX  
{ `Eu,SvkFw  
return nSplitter; kv+^U^WoU  
} cT/mi":8{  
%0}}Qt  
2DJg__("  
public void setNSplitter(int nCount) L;{{P7  
{ d=uGB"  
nSplitter = nCount; [cznhIvyO  
} K
{@xZ)  
} 0_+ & [g}  
}-XZ1qr  
cwtlOg  
/* ~[
og\QZX  
**Utility.java Vmh$c*TE  
*/ vRf$#fBEQ  
package NetFox; 7w8UnPuM  
RF'nwzM3  
-J#RGB{7  
public class Utility { N1.
1  
R-OO1~W=  
8d Fqwpw8  
public Utility() Y
hmveV  
{ WDV=]D/OE  
6d/v%-3  
gVh&c4  
} xWK/uE(  
kz6fU\U  
//线程睡眠 5ZH3}B^L$  
public static void sleep(int nSecond) P2C>IS  
{ "XLtrAu{  
try{ m8R=wb :  
Thread.sleep(nSecond); j)YX=r;xM  
} "_dg$j`Y&&  
catch(Exception e) y^n
T G  
{ 1=,2i)  
e.printStackTrace (); m}oR*<.  
} f/IQ2yT-:D  
} f5un7,m  
JhTr{8{  
//日志 |_7k*:#q:  
public static void log(String sMsg) .7LQ l?  
{ d]^m^
 
System.err.println(sMsg); _~C1M&b(X3  
} $o\z4_I  
y&O?`"Uv/M  
G{>PYLxOb  
public static void log(int sMsg) e"bzZ!c&~V  
{ L$sENOm  
System.err.println(sMsg); ^ACrWk~UY  
} J-uQF|   
} |s(Ih_Zn  
l`A&LQ[  
0rI/$  
/* IhZn  
**TestMethod.java /N<aN9Z<x,  
*/ enQW;N1_M  
package NetFox; a8ouk7G  
6oZHSjC*  
c?}G;$  
public class TestMethod { w{2CV\^>5  
%0/qb0N&  
)X|)X,~+-  
public TestMethod() tCGx]\  
{ ///xx/weblogic60b2_win.exe &k)v/  
try{ FPF$~ sX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); S^==$TT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); mf{M-(6'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); SDE$ymPx  
fileFetch.start(); qz3 Z'  
} TecMQ0 KD  
catch(Exception e){e.printStackTrace ();} |mRlP5  
|j9aTv[`  
-\;0gnf{J  
} t0@AfO.'1  
(U# Oj"  
5p:BHw;%;  
public static void main(String[] args) IpSWg  
{ YwF&-~mp7n  
new TestMethod(); yZ)9Hd  
} aT}Hc5L,b  
} Ev7v,7`z  
点击下载更多相关资料