http断点续传简单实现（java)

/* @ yg|OA}  
**SiteFileFetch.java e"o6C\c  
*/ vSYunI  
package NetFox; @wEKCn|}o  
import java.io.*; _ r^90  
import java.net.*; +YQ~t,/  
FU]8.)`G  
3lLW'g&=  
public class SiteFileFetch extends Thread { XUQW;H  
oieQ2>lYh  
w8ZHk?:  
SiteInfoBean siteInfoBean = null; //文件信息Bean Y>78h2AU  
long[] nStartPos; //开始位置 BYr_Lz|T  
long[] nEndPos; //结束位置 J:g<RZZ1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Z/
NGv  
long nFileLength; //文件长度 +B`'P9Zk@  
boolean bFirst = true; //是否第一次取文件 z,}c?BP  
boolean bStop = false; //停止标志 &e HM#as  
File tmpFile; //文件下载的临时信息 KD%xo/Z.  
DataOutputStream output; //输出到文件的输出流 EU^}NZW&v:  
RWh9&O:6'  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） J3lG"Ww  
public SiteFileFetch(SiteInfoBean bean) throws IOException @Hspg^  
{ F= _uNq  
siteInfoBean = bean; IFC%%It5,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0.J1!RIK/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {FV,j.D  
if(tmpFile.exists ()) dJ%wVY0z=  
{ VVI8)h8  
bFirst = false; fW5"4,  
read_nPos(); $,; ;u:-  
} ~{1/*&P  
else @O}IrC!bf  
{ $tDCS  
nStartPos = new long[bean.getNSplitter()]; vDK:v$g  
nEndPos = new long[bean.getNSplitter()]; ;Ch+X$m9  
} =2.tu*!C  
B91S h`  
Pp1zW3+Q  
1EC-e|M.  
} ibZt2@GB)I  
pPiYPfs  
R "/xne  
public void run()  Z;j/K  
{ >G-8FL  
//获得文件长度 mHK@(D7X  
//分割文件 #/n|@z'  
//实例FileSplitterFetch AkYupP2]v  
//启动FileSplitterFetch线程 G8^0^@o  
//等待子线程返回 ":UWowJO  
try{ MO));M)  
if(bFirst) Lf,CxZL5  
{ 'L>&ZgLy  
nFileLength = getFileSize(); rQu  
if(nFileLength == -1) F:[7^GQZ{  
{ ou<S)_|Iu  
System.err.println("File Length is not known!"); N`,7FI}  
} 5`4}A%@&  
else if(nFileLength == -2) kP!%|&w;  
{ Tm%$J  
System.err.println("File is not access!"); ;=5@h!@R  
} Qa,NGP.  
else itqQ)\W  
{ GN:Ru|n  
for(int i=0;i<nStartPos.length;i++) s jL
*I  
{ S+.21,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ri/t(m^{W  
} w8AJ#9W  
for(int i=0;i<nEndPos.length-1;i++) ! 6p>P4TT  
{ o|z+!,  
nEndPos = nStartPos[i+1]; ^?$D.^g  
} \]Y\P~n  
nEndPos[nEndPos.length-1] = nFileLength; l 8O"w&  
} E/"YId
`A  
} ~pHJ0g:t  
b\SXZN)Be  
{c v;w  
//启动子线程 6V'wQqJ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /M0l p   
for(int i=0;i<nStartPos.length;i++) 3[MdUj1y[  
{ :`:xP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  =3h+=l[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !7A"vTs  
nStartPos,nEndPos,i); :.C+?$iuX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,|e}Y [  
fileSplitterFetch.start(); ??%)|nj.  
} U>/<6Wd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IY];S
s&i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 
R<0Fy=z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R^jlEt\&P  
nEndPos = " + nFileLength); GwgFi@itN  
// fileSplitterFetch[nPos.length-1].start(); k-{yu8*';  
#=X)Jx~  
ShC_hi  
//等待子线程结束 Jy]FrSm^  
//int count = 0; :~\LOKf  
//是否结束while循环 [NQmL=l  
boolean breakWhile = false; ^
c/mj9M#C  
B1|
?RfCe  
Qy4X#wgD  
while(!bStop) Ty`-r5  
{ !a' K&  
write_nPos(); IkSX\*  
Utility.sleep(500); e{v,x1Y_z(  
breakWhile = true; pG)9=X!9  
P#AAOSlLV  
gsW=3m&`  
for(int i=0;i<nStartPos.length;i++) Z6 tE{/  
{ ?RZq =5Um&  
if(!fileSplitterFetch.bDownOver) k%{ l4  
{ t{+M|Y  
breakWhile = false; o)0C-yO0qf  
break; f&6w;T=  
} 6{5q@9F  
} D~cW ]2  
if(breakWhile) =YWT|%^uX  
break; A{4Dzm!  
aML#Z|n  
' be P  
//count++; u8|@|t  
//if(count>4) v2IEJ  
// siteStop(); 5iP8D<;o5  
} bBA$}bv  
)J;ny!^2  
6a7vlo  
System.err.println("文件下载结束！"); +c-6#7hh  
} uZ@-e|qto  
catch(Exception e){e.printStackTrace ();} ksTzXG8  
} {d| |q<.
-  
7raSf&{&6b  
LEWa6'0rq
 
//获得文件长度 r])Z9bbi  
public long getFileSize() AnRlH  
{ _o\>V:IZ  
int nFileLength = -1; [6O04"6K  
try{ @XeEpDn]  
URL url = new URL(siteInfoBean.getSSiteURL()); DNmb[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $"/UK3|d  
httpConnection.setRequestProperty("User-Agent","NetFox"); DLU[<!C  
l+t #"3  
;?0_Q3IML  
int responseCode=httpConnection.getResponseCode(); _B}9f  
if(responseCode>=400)
:qBGe1Sv(  
{ /j11,O?72  
processErrorCode(responseCode); I"B8_  
return -2; //-2 represent access is error f(!E!\
&n^  
} &j3` )N  
GaHA%  
K*[9j 0  
String sHeader; M|ms$1x  
w2k<)3 g~  
DUqJ y*F(  
for(int i=1;;i++) w nWgy4:  
{ j+$M?Z^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9e]'OKL+  
//Utility.log(in.readLine()); o\&~CW~@~  
sHeader=httpConnection.getHeaderFieldKey(i); `(3SfQ-  
if(sHeader!=null) q1STRYb  
{ aQga3;S!  
if(sHeader.equals("Content-Length")) %?Rs*-F.~1  
{ 4e}{$s$Xx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *vb^N0P  
break; n|6?J_{<b>  
} Sobtz}A*  
} 2%5?Fn=  
else %Mh Q  
break; !z?0 :Jg  
} .xEJaID\N  
} `-o5&>'nf  
catch(IOException e){e.printStackTrace ();} MvBD@`&7  
catch(Exception e){e.printStackTrace ();} F,Q?s9s  
!Ri r&gF  
8[oYZrg  
Utility.log(nFileLength); bQ<b[  
C>4UbU  
k5wi'  
return nFileLength; 4\\.n  
} i=-8@  
WK*S
4c  
R+d< fe  
//保存下载信息（文件指针位置） w(Gz({l+  
private void write_nPos() 3I]Fdp)'  
{ '[Xl>
Z[  
try{ #K|0laul  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \04mLIJr9  
output.writeInt(nStartPos.length); |gW    
for(int i=0;i<nStartPos.length;i++) 3524m#4&@  
{ Qo.Uqz.C  
// output.writeLong(nPos); vGMJ^q  
output.writeLong(fileSplitterFetch.nStartPos); DKTD Z*  
output.writeLong(fileSplitterFetch.nEndPos); %
MbyKz:X  
} t-!m vx9Z  
output.close(); {M[~E|@D  
} ^Z#@3=  
catch(IOException e){e.printStackTrace ();} :&9T
W]*g  
catch(Exception e){e.printStackTrace ();} wYjQV?,  
} ~H u"yAR  
1+a@k  
&Xv1[nByU  
//读取保存的下载信息（文件指针位置） ]rnXNn;  
private void read_nPos() {\EOo-&A  
{ J,(7.+`~#  
try{ MQJ%He"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3"Yif  
int nCount = input.readInt(); 0yz~W(tsm  
nStartPos = new long[nCount]; S7CV w,2  
nEndPos = new long[nCount]; 9_UN.]  
for(int i=0;i<nStartPos.length;i++) +bUW!$G  
{ -TTs.O8P|<  
nStartPos = input.readLong(); =e
{.yggE  
nEndPos = input.readLong(); r1;e 0\?`  
} Yy hny[fa9  
input.close(); lVoik*,B  
} ETO$9}x[  
catch(IOException e){e.printStackTrace ();} @(>XOj?+  
catch(Exception e){e.printStackTrace ();} [zQWyDu  
} #]y5zi  
O#:&*Mv  
;%Q&hwj  
private void processErrorCode(int nErrorCode) ' S,2  
{ &{ZSE^  
System.err.println("Error Code : " + nErrorCode); R*bmu  
} B)6#Lp3  
t.)AggXj#  
{fU?idY)c  
//停止文件下载 HxIoA  
public void siteStop() P6YQK+  
{ s"coQ!e1.  
bStop = true; \(fq8AL?  
for(int i=0;i<nStartPos.length;i++) Xu#:Fe}:  
fileSplitterFetch.splitterStop(); Xpl?g=B&u  
88l,&2q  
nP1GW6P
u  
} 8
_a3'o%5  
} `%=<R-/#7S  
//负责部分文件的抓取 iP#=:HZu;  
**FileSplitterFetch.java aM
J;bQD  
*/ W#{la`#Bu  
package NetFox; h/K@IAd  
+c) TDH  
#9:2s$O[x  
import java.io.*; bi$VAYn.^  
import java.net.*; =EpJZt  

0hwj\{"  
|dk[cX>  
public class FileSplitterFetch extends Thread { +s~.A_7)  
H^ BYd%-  
xA #H0?a]  
String sURL; //File URL pj; I)-d/  
long nStartPos; //File Snippet Start Position 6
t7fa<  
long nEndPos; //File Snippet End Position vq>l>as9O  
int nThreadID; //Thread's ID k>5O`Y:  
boolean bDownOver = false; //Downing is over ;LQ9#M?  
boolean bStop = false; //Stop identical CGZ^hoh/  
FileAccessI fileAccessI = null; //File Access interface opD-vDa h  
bX2"89{  
L/i(KF{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ARWZ; GX  
{ * t!r@k  
this.sURL = sURL; 9i%9  
this.nStartPos = nStart; wf
9z"B  
this.nEndPos = nEnd; +EkW>$  
nThreadID = id; u7].}60.'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #ep
y%>  
} ,2,5Odrz  
mCdgKr|n  
e&1\'Zq?>  
public void run() Mu2`ODe]  
{ OCK>%o$[  
while(nStartPos < nEndPos && !bStop) BQ#L+9%  
{ m@\ZHbq  
re`t ]gzb  
<3Gqv9Y&  
try{ :=fvZAWD  
URL url = new URL(sURL); iM5vrz`n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9Cvn6{  
httpConnection.setRequestProperty("User-Agent","NetFox"); X+l'bp]Ry
 
String sProperty = "bytes="+nStartPos+"-"; :E'P7A  
httpConnection.setRequestProperty("RANGE",sProperty); O+"ac /
r  
Utility.log(sProperty); 8I#D`yVKc  
aC\4}i<  

9%,;XQ  
InputStream input = httpConnection.getInputStream(); &9B_/m3  
//logResponseHead(httpConnection); YMzBAf  
Z7#7N wy4  
Os&1..$Nb  
byte[] b = new byte[1024];  H!eh J$[  
int nRead; -Zy)5NB-tZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) McP.9v}H0_  
{ "sbBe73 m  
nStartPos += fileAccessI.write(b,0,nRead); Lo`F  
//if(nThreadID == 1) 4M`Xrfwm'[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `iYc<N`  
} :t$A8+A+0  
{8CWWfHCD  
&=w|vB)(p  
Utility.log("Thread " + nThreadID + " is over!"); z^`]7i  
bDownOver = true; r_o<SH  
//nPos = fileAccessI.write (b,0,nRead); 2P}I'4C-  
} f
1cl';  
catch(Exception e){e.printStackTrace ();} SGf9U^ds  
} P;U@y"s  
} >4)g4~'n!  
Rt4di^v  
.h8M  
//打印回应的头信息 iJnh$jo  
public void logResponseHead(HttpURLConnection con) h|W%4|]R)  
{ TVkcDS  
for(int i=1;;i++) zO.6WJ  
{ Rc9<^g`  
String header=con.getHeaderFieldKey(i); mK\aI  
if(header!=null) }~zO+Wf2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Uf2:gLrF  
Utility.log(header+" : "+con.getHeaderField(header)); Auac>')&Q  
else #93}E Y  
break; [j0w\{  
} JMsHK,(  
} %zljH"F  
n7iE8SK|k  
DrS?=C@  
public void splitterStop() otq,R6 ^  
{ %V_eJC""?  
bStop = true; mw+j|{[  
} h$&rE@N|  
l%PnB )F  
]
09yy  
} DTy/jaK  
M&e8zS  
+Jq`$+%C  
/* #s^s_8#&e  
**FileAccess.java mQ,{=C=D  
*//文件访问(定位，写) # #>a&,  
package NetFox; ptR  
import java.io.*; iS-K ~qa  
H m8y]>$  
;&mxqY8`'  
public class FileAccessI implements Serializable{ rw*M&qg!z  
t-EV h~D1p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ITvHD-,\  
RandomAccessFile oSavedFile; -tP.S1D  
long nPos; |[WL2<  
Q X):T#^V  
V.j#E1P  
public FileAccessI() throws IOException ..$>7y}  
{ a7 )@BzF#  
this("",0); R0IF'  
} M,G8*HI"  
`,-STIh)  
%8<2>  
public FileAccessI(String sName,long nPos) throws IOException ;MZbL)  
{ 1.dX)^\  
oSavedFile = new RandomAccessFile(sName,"rw"); ZbyG*5iq  
this.nPos = nPos; >w2f8tW`PP  
oSavedFile.seek(nPos); 6o(lObfo  
} enPYj.*/0  
c}cG<F  
%&1$~m0  
public synchronized int write(byte[] b,int nStart,int nLen) kA,4$2_o  
{ JP%RTGu  
int n = -1; .h6Y<
E  
try{ wRi~Yb?  
oSavedFile.write(b,nStart,nLen); [oJ& J>U'  
n = nLen; JU2P%3  
} `axQd%:AC  
catch(IOException e) `D"1 gD}{A  
{ QX+Y(P`vMK  
e.printStackTrace (); 'A1E^rl]=  
} *vD/(&pQ1:  
E6Q91Wz9f  
Ej5^Y ?-6  
return n; v?{vg?vI  
} d3(+ztmG!  
2{gwY85:  
2D_6
  
} D:6N9POB  
C\/b~HU  
m&ZJqsZIL  
/* PbQE{&D#  
**SiteInfoBean.java ]3 j[3'  
*/ qw)Key  
package NetFox; %0 qc@4  
x' ?.~  
]%||KC!O  
public class SiteInfoBean { \`&xprqAw  
%cd]xQpCp  
i _8zjj7  
private String sSiteURL; //Site's URL k3/4Bt G/  
private String sFilePath; //Saved File's Path wvX"D0eVn  
private String sFileName; //Saved File's Name wH!}qz/  
private int nSplitter; //Count of Splited Downloading File Iw*C*%}[Z  
e00RT1L  
Z{ %Uw;d  
public SiteInfoBean() JkJhfFV  
{//nSplitter的缺省值为5 > `0| X  
//default value of nSplitter is 5 yq!CWXZ2  
this("","","",5); ~6MMErSj  
} (w}r7`n  
do*W
x2:R  
$Q#?`j  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 37~rm  
{ j}"]s/= 6  
sSiteURL= sURL; /LSq%~UF  
sFilePath = sPath; vg5E/+4gp%  
sFileName = sName; Le_CIk 5YL  
this.nSplitter = nSpiltter; ?'T"?b<  
HoMQt3C
 
Qk|( EFQ9  
} tI `w;e%HN  
"3v7gtGG  
-5o?#%  
public String getSSiteURL() Hc>([?P%t  
{ 8R&z3k;!t  
return sSiteURL; XpOCQyFnM  
} z=u~]:.1O  
i4 P$wlO  
=SA 4\/  
public void setSSiteURL(String value) Bk@bN~B4  
{ |%n|[LP'  
sSiteURL = value; 3SmqXPOw  
} h!ZZ2[  
ER/\ +Z#Z  
B>1M$3`E  
public String getSFilePath() B6-AIPb  
{ |WQD=J%~(  
return sFilePath; oJhEHx[f  
} hcj{%^p  
{E3;r7  
}`#j;H$i  
public void setSFilePath(String value) kVy"+ZebK  
{ >>/nuWdpO  
sFilePath = value; "sC$%D<oc  
} \%Pma8&d  
R%Kl&c  
t!NrB X  
public String getSFileName() % cU-5\xF  
{ [ e$]pN%  
return sFileName; XA=|]5C  
} mI2|0RWI)l  
SB5@\^  
rHH#@Zx  
public void setSFileName(String value) rD_Ss.\^g  
{ 7$;c6_se  
sFileName = value; "X\q%%P=?  
} =B1`R%t  
.n?5}s+q  
D86K$IT  
public int getNSplitter() ~Ay  
{ S^*(ALFPj  
return nSplitter; >eTf}#s?S  
} <t% Ao,"  
Fj'\v#h  
R
h5@[cg%  
public void setNSplitter(int nCount) h;&&@5@lM  
{ |j\eBCnH3  
nSplitter = nCount; u0<d2Y  
} 3 ATN?V@  
} #u!y`lek  
@Z"QA!OK~c  
vbW\~xf  
/* **"zDY*?W  
**Utility.java #sozXz
a\G  
*/ ?14X8Mb8W_  
package NetFox; Fo--PtY`p  
,:\zXESy4  
&QiAM`MbC=  
public class Utility { / nC$?w  
K*hf(w9="%  
"a2H8x  
public Utility() _p3WE9T  
{ cx,u2~43A&  
,i1fv "  
9 ayH:;  
} Py(wT%w
 
sIP6GWK$  
//线程睡眠 b@UF PE5jy  
public static void sleep(int nSecond) LGdf_M-f  
{ 0~LnnDN  
try{ &q kl*#]  
Thread.sleep(nSecond); w
pPxEp/  
} c/,|[t  
catch(Exception e) + xkMW%e<  
{ zwF7DnW<<  
e.printStackTrace (); ZVC
v(J  
} JC1BUheeb  
} Y
+S~b  
sZ\i(eIU  
//日志 @5uyUSt]  
public static void log(String sMsg) 7]0\[9DyJ  
{ :{e`$kz  
System.err.println(sMsg); .>cL/KaP  
} * S+7BdP  
*{L<BB^  
]7Xs=>"Iw  
public static void log(int sMsg) DY%T`}  
{ pw(*X,gj  
System.err.println(sMsg); c{r6a=C  
} la6e`  
} NWq [22X |  
6Wcn(h8%*  
c"jhbH!u4  
/* V3.vE,  
**TestMethod.java e3bAT.P  
*/ [9
##Kb  
package NetFox; -b
G#h)yj  
$txWVjR?\  
*HfW(C$  
public class TestMethod { DXw9@b  
}sm56}_  
3n=cw2FG  
public TestMethod() et7T)(k0  
{ ///xx/weblogic60b2_win.exe 4%W
n}@  
try{ yM\tbT/l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?7uStqa  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pNk,jeo
  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e=NQY8?  
fileFetch.start(); %QlBFl0a  
} ;U5x'}%0]  
catch(Exception e){e.printStackTrace ();} Ib<5u  
YQw/[  
LP-KD  
} cUX]tiC0  
=&<$I  
1Rb<(%   
public static void main(String[] args) N NXwT0t  
{ pu m9x)y1  
new TestMethod();  s`{#[&[  
}
{mq$W  
} jTxChR  
点击下载更多相关资料