http断点续传简单实现（java)

/* svl!"tMXl  
**SiteFileFetch.java l'wu-  
*/ nqUn
DnP2c  
package NetFox; -.8K"j{N  
import java.io.*; |pWu|M _'  
import java.net.*; t&q~ya/C  
m*N8!1Ot  
~n%Lo3RiP  
public class SiteFileFetch extends Thread { ) 5$?e  
LD5`9-  
{"{]S12N  
SiteInfoBean siteInfoBean = null; //文件信息Bean \R]2YY`EP  
long[] nStartPos; //开始位置 L3xN#W;m7  
long[] nEndPos; //结束位置 :DNI\TmhJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2y;vX|lX]  
long nFileLength; //文件长度 ~&qvS  
boolean bFirst = true; //是否第一次取文件 su1fsoL0  
boolean bStop = false; //停止标志 Dv/7w[F  
File tmpFile; //文件下载的临时信息 ,zHL8SiTX  
DataOutputStream output; //输出到文件的输出流 tcv(<0  
nQ+5jGP1  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） FjtS  
public SiteFileFetch(SiteInfoBean bean) throws IOException k_wcol,W  
{ 5 m-/N?c  
siteInfoBean = bean; $`/UG0rdC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w?|qKO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ; YQB  
if(tmpFile.exists ()) g@4~,  
{ [R%*C9Y d  
bFirst = false; 4W*o:Y!  
read_nPos(); K$/"I0YyI  
} 'b}RFzEn  
else /NCN wAj7  
{ v^t7)nx^  
nStartPos = new long[bean.getNSplitter()]; 2z;3NUL$n  
nEndPos = new long[bean.getNSplitter()]; WlvT&W  
} 4=|Q2qgFV  
M80Q6K  
pFNU~y'Kf  
0NZ'(qf~9  
} >uq0}HB$a  
\OFmd!Cz  
zm5PlG
 
public void run() ,-E'059  
{ Komdz/g  
//获得文件长度 }s<;YC  
//分割文件 *9kg\#  
//实例FileSplitterFetch ZSe30Rl\  
//启动FileSplitterFetch线程 X5 or5v  
//等待子线程返回 h`N2M,  
try{ xi "3NF%=  
if(bFirst) z|%Pi J,  
{ X5[t6q!  
nFileLength = getFileSize(); {x,)OgK!{  
if(nFileLength == -1) 3Q=\W<Wu  
{ wyB]!4yy,  
System.err.println("File Length is not known!"); .-tR <{ g  
} $[fqTh  
else if(nFileLength == -2) d!R+-Fp  
{ r/ g{j  
System.err.println("File is not access!"); jF}kV%E  
} g%S/)R,,ct  
else 7:uz{xPK6  
{ a4~B  
for(int i=0;i<nStartPos.length;i++) 1Xm>nF~  
{ 0'pB7^y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]7W!f 2@  
} DAWF =p]  
for(int i=0;i<nEndPos.length-1;i++) q 9xA.*  
{ 87l*Y|osP  
nEndPos = nStartPos[i+1]; )/)u.$pi  
} SQ2v  
nEndPos[nEndPos.length-1] = nFileLength; bRm;d_9zC  
} lD[@D9  
} j0{`7n  
H2: Zda#  
-;_"Y]#  
//启动子线程 -sJD:G,%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 16 `M=R  
for(int i=0;i<nStartPos.length;i++) 8o%Vn'^t  
{ b,~pwbHf  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^t gjs$M|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *,lDo9  
nStartPos,nEndPos,i); ?|W3RK;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Bt@?l]Y  
fileSplitterFetch.start(); zc)nDyn  
} _p0Yhju?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q2m
[XcnX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e3CFW_p  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;u'VR}4ph  
nEndPos = " + nFileLength); L QV@]z&  
// fileSplitterFetch[nPos.length-1].start(); mm:TR?^  
}'x)e  
yVK ; "  
//等待子线程结束 ZOV,yuD{8{  
//int count = 0; zi6J|u  
//是否结束while循环 [}HPV+j=U  
boolean breakWhile = false; wQy~5+LE  
,%IP27bPW  
"*X\'LPs=  
while(!bStop) g{}<ptx]  
{ 8
el6z2  
write_nPos(); E<3xv;v8r  
Utility.sleep(500); \HzmhQb+m  
breakWhile = true; xtv%C  
' abEY  
#?S"y:  
for(int i=0;i<nStartPos.length;i++) .cs x"JC  
{ e Fz$h2*B  
if(!fileSplitterFetch.bDownOver) 4_QfM}Fyp  
{ t.;._'  
breakWhile = false; =T2SJ)  
break; 9;7"S.7AV  
} @B>D>B  
} 7_s+7x =  
if(breakWhile) S5>ztK.e  
break; sd%)g<t  
X+A@//,7  
8h=m()Eu  
//count++; hizM}d-"C  
//if(count>4) hIqUidJod  
// siteStop(); XTF[4#WO  
} RA<ky*^dr  
WIi,`/K+  
EL3X8H  
System.err.println("文件下载结束！"); `(?c4oq,c>  
} l]zQSXip  
catch(Exception e){e.printStackTrace ();} L1!~T+%uQ  
} +jB;  
_w?!Mu  
bv]SR_Tiq  
//获得文件长度 @,sjM]  
public long getFileSize() aB;f*x  
{ s1cu5eCt  
int nFileLength = -1; LhAW|];  
try{ 3h.,7,T  
URL url = new URL(siteInfoBean.getSSiteURL()); yD& Y`f#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y'^U4# (  
httpConnection.setRequestProperty("User-Agent","NetFox"); DQW)^j h  
L{jx'[C  
D )`(b  
int responseCode=httpConnection.getResponseCode(); &\6},
JN  
if(responseCode>=400) T:{&eWH  
{ =ZURh_{xV  
processErrorCode(responseCode); ]}b  
return -2; //-2 represent access is error !~?/D  
} "0PsCr}!  
{u y^Bui}  
dcmf~+T  
String sHeader; =6ru%.8U,  
1gBLJ0q  
$dI mA  
for(int i=1;;i++) &UnhYG{A  
{ [5IbR9_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Co(N8>1  
//Utility.log(in.readLine()); $[`rY D/.  
sHeader=httpConnection.getHeaderFieldKey(i); F%p DF\  
if(sHeader!=null) ["&{^  
{ /Q7q2Ne^*  
if(sHeader.equals("Content-Length")) aG;F=e  
{ H:hM(m0?q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Dmi.@.  
break; -V4{tIQY  
} qVfn(rZ  
} HM)D/CO,?  
else b6k_u9m^E  
break; @R`6jS_gK  
} D ON.)F  
} T\p>wiY2|F  
catch(IOException e){e.printStackTrace ();} `!N}u  
catch(Exception e){e.printStackTrace ();} <FBH;}]  

/# Jvt  
b1#C,UWK  
Utility.log(nFileLength); rAHP5dx:  
p({@t=L3g  
GO2q"a  
return nFileLength; Pi5MFw'v  
} 7)<Ib j<M  
*j&\5|^V  
EmO[-W|2  
//保存下载信息（文件指针位置） X(x,6cC  
private void write_nPos() Jy}~ZY  
{ h9m|f|cH  
try{ c"kB@P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %E@o8  
output.writeInt(nStartPos.length); m_Ed[h/I  
for(int i=0;i<nStartPos.length;i++) tik*[1it  
{ &D[M<7T  
// output.writeLong(nPos); 3YLfh
`6  
output.writeLong(fileSplitterFetch.nStartPos); hY{4_ie=8  
output.writeLong(fileSplitterFetch.nEndPos); YC 4c-M  
} )!rD&l$tE  
output.close(); ?/MkH0[G=  
} d m"R0>  
catch(IOException e){e.printStackTrace ();} bf.+Ewb(  
catch(Exception e){e.printStackTrace ();} tgCp2`n  
} U1/I(w  
+~G:z|k  
f@ |[pT  
//读取保存的下载信息（文件指针位置） [Uq`B&F:  
private void read_nPos() S[9b I&C  
{ -eK0 +beQ  
try{ w{T$3F`@9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,{:qbt  
int nCount = input.readInt(); eSObOG/  
nStartPos = new long[nCount]; VFZyWX@#u  
nEndPos = new long[nCount]; k0I$x:c  
for(int i=0;i<nStartPos.length;i++) [>GblL  
{ ]aMDx>OE  
nStartPos = input.readLong(); Jgr;'U$  
nEndPos = input.readLong(); feB 
?  
} %KO8i)n  
input.close(); 5s^vC2$)  
} Wx3DWY;  
catch(IOException e){e.printStackTrace ();} lt4IoE`tk?  
catch(Exception e){e.printStackTrace ();} _z%\53h  
} V+1
c<LwT  
r0k:RJP  
C[znUI>  
private void processErrorCode(int nErrorCode) q7aqbkwz}  
{ WL
U_t65  
System.err.println("Error Code : " + nErrorCode); *
^
]  
} 3
)>re&  
X$ul=iBs  
@ ^F{  
//停止文件下载 "'``O~08/  
public void siteStop() 1r.2bL*~jw  
{ @qcUxu4  
bStop = true; GNmP_N  
for(int i=0;i<nStartPos.length;i++) EmUt/]  
fileSplitterFetch.splitterStop(); ]g9SUFM  
xv$fw>  
Kk=>"?&  
} I&15[:b=-  
} }vB{6E+h/w  
//负责部分文件的抓取 W^[QEmyn  
**FileSplitterFetch.java }Tm+gJA  
*/ +K'YVB U}  
package NetFox; (L4C1h_]9  
34)l3UI~  
S`
mB1(h  
import java.io.*; 7`L]aRS[  
import java.net.*; d<ES  
<<qzZ+u  
[8tpU&J  
public class FileSplitterFetch extends Thread { >(n/  
R3_;!/
1  
|]q{qsy  
String sURL; //File URL V3*@n*"N;  
long nStartPos; //File Snippet Start Position GfP'  
long nEndPos; //File Snippet End Position ?6vGE~MuR  
int nThreadID; //Thread's ID 7!`1K_v6  
boolean bDownOver = false; //Downing is over Y=sv   
boolean bStop = false; //Stop identical F\;l)  
FileAccessI fileAccessI = null; //File Access interface JM0+-,dl[  
Z[z" v  
kd&~_=Q  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Bf^K?:r"V  
{ ''9K(p6  
this.sURL = sURL; '^7Z]K<v  
this.nStartPos = nStart; mBrZ{hqS  
this.nEndPos = nEnd; \[]BB5)8  
nThreadID = id; K-*ZS8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #+"D?  
} "\9beK:l  
B"4A1!  
"3 2Ua3m:G  
public void run() KTo}xLT  
{ H<^3H  
while(nStartPos < nEndPos && !bStop) Zg= {  
{ 1$}Tn
 
]x& R=)P  
\mb@-kM)  
try{ ;/23CFYM  
URL url = new URL(sURL); }|=Fnyj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K43`$  
httpConnection.setRequestProperty("User-Agent","NetFox"); S9b=?? M)  
String sProperty = "bytes="+nStartPos+"-"; rwwyYIlEg  
httpConnection.setRequestProperty("RANGE",sProperty); a&mL Dh/  
Utility.log(sProperty); [UdJ(cGf  
t]3:vp5N]  
H,/=<Th;i  
InputStream input = httpConnection.getInputStream(); `7``1TL  
//logResponseHead(httpConnection); _q-k1$o
$  
4yMi9Ri4H  
)99^58my  
byte[] b = new byte[1024]; 5K|`RzZ`B$  
int nRead; 5D^2 +`$/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W1M Bk[:Q  
{ 4ee-tKH  
nStartPos += fileAccessI.write(b,0,nRead); 0Iyb}
  
//if(nThreadID == 1) '|tmmoY6a:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <[gN4x>'  
} 8&x&Ou$("V  
/^~)iTwH  
- t4F  
Utility.log("Thread " + nThreadID + " is over!"); \dB z-H'@  
bDownOver = true; ij_5=4aZ
-  
//nPos = fileAccessI.write (b,0,nRead); p4uO
bK,  
} 9j;!4AJ1t  
catch(Exception e){e.printStackTrace ();} JGhK8E  
} ^#h ;
bX#  
} 'OhGS
s|  
[w FK!?  
(w<llb`]  
//打印回应的头信息 sA"B/C|(g  
public void logResponseHead(HttpURLConnection con) \<}e?Yx%  
{ gZz5P
>^  
for(int i=1;;i++) |hvclEu,  
{ xf:|lQf  
String header=con.getHeaderFieldKey(i); O+DYh=m*p  
if(header!=null) \$,;@H5I^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k_OzkEM9!  
Utility.log(header+" : "+con.getHeaderField(header)); 1NN#-U  
else &6\E'bBt  
break; A(C0/|#V  
}
y]k{u\2
A  
} ,}^;q58  
*'@T+$3s  
? a*yK8S  
public void splitterStop() @C~gU@F  
{ 9~r8$,e  
bStop = true; ``h*A  
} \gir  
pe\]}&  
Wjd_|Kui  
} >/-Bg:  
,F|49i.K  
%:-2P  
/* A22'qgKm@  
**FileAccess.java dP/1E6*m  
*//文件访问(定位，写) YO.+06X  
package NetFox; sdQ"[`~2R  
import java.io.*; *APTgXYR  
-0*z"a9<p8  
p"Di;3!y!  
public class FileAccessI implements Serializable{ ?j8_j  
^"J)^3j<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :RXzqC  
RandomAccessFile oSavedFile; ?[X^'zz}  
long nPos; w[;5]z  
VF:<q  
F{m?:A  
public FileAccessI() throws IOException H|d"45J_  
{ l.SoiFDd  
this("",0); ~5~Cpu
2v7  
} =%crSuP  
0{47TX*YX  
w
"h3e  
public FileAccessI(String sName,long nPos) throws IOException
KD..X~Me  
{ =|3*Y0  
oSavedFile = new RandomAccessFile(sName,"rw"); M
+M\3U  
this.nPos = nPos; F*,RDM'M  
oSavedFile.seek(nPos); Ij7[2V]c  
} KA9v?_@{F  
T^nOv2@,  
Up1e4mNL  
public synchronized int write(byte[] b,int nStart,int nLen) H')8p;~{}  
{ I^gLiLUN*6  
int n = -1; 6PRP&|.#  
try{ AUm5$;o,/  
oSavedFile.write(b,nStart,nLen); y?xFF9W@H  
n = nLen; Zx%6pZ(.  
} e:;u_be~  
catch(IOException e) r)f+j@KF  
{ Wtj*Z.=:  
e.printStackTrace (); TDW\
n  
} 3ZL<6`YF  
8]% e[  
J@(69&  
return n; lD1m<AC  
} <L<d_  
5wm(gF_t  
6tBe,'*  
} u'"]{.K>fb  
= _/XFN  
|Y;[)s =q  
/* >B+!fi'SS>  
**SiteInfoBean.java B5/
"2i  
*/ %_ Vj'z~T  
package NetFox; 0-IL@Di`F  
=a_ >")  
%2`.*]L  
public class SiteInfoBean {  D
~t  
*~jTE;J  
,uCgC4EP  
private String sSiteURL; //Site's URL ;0:[X+"(  
private String sFilePath; //Saved File's Path M_f.e!?  
private String sFileName; //Saved File's Name @@#h-k%k-  
private int nSplitter; //Count of Splited Downloading File 6{?B`gm7g  
C.?~D*Q  
l[b`4  
public SiteInfoBean() ze#r/j;sw  
{//nSplitter的缺省值为5 e#|YROHf  
//default value of nSplitter is 5 ECvTmU'=  
this("","","",5); u:%Ln_S  
} ')KuLVE}S  
tE;c>=>t  
g3vR\?c`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l !:kwF  
{ Z3z"c B  
sSiteURL= sURL; [ih^
VlZ  
sFilePath = sPath; C;XhnqWv+l  
sFileName = sName; 4)E$. F^   
this.nSplitter = nSpiltter; g,}_&+q:.M  
}\aJ%9X02  
<,Pk  
} .%+y_.l  
Q?{^8?7  
o6)U\z  
public String getSSiteURL() OH6-\U'.Z  
{ u\o~'Jz  
return sSiteURL; 9qX)FB@'i;  
} e#z#bz2<  
$'93:9tg
 
F0/!+ho  
public void setSSiteURL(String value)
T3h1eU  
{ *w[0uQL5Z  
sSiteURL = value; NbUbLzE  
} Eanwk` Rx  
6=g! Hs{  
V ^hR%*i'  
public String getSFilePath() i&\cDQ 3  
{ ..UA*#%1  
return sFilePath; I)q"M]~  
} m,PiuR>  
WXe]Q bg  
Mk!bmFZOZ  
public void setSFilePath(String value) #]@|mf q  
{ &r1]A&  
sFilePath = value; O*ER3  
} sk7]s7  
EfGy^`,'G  
\U.js-  
public String getSFileName() M&` b\la  
{ aBWA hn  
return sFileName; 4XIc|a Aa  
} 9G^gI}bY  
ZMO ym=  
WGHf?G/s  
public void setSFileName(String value) .pyNET  
{ sI6coe5n  
sFileName = value; ,#K{+1z:  
} YpEH(tq  
##a.=gl  
1;eWnb(  
public int getNSplitter() W}M3z  
{ cr~.],$Om  
return nSplitter; U[W &D%'  
} dK>sHUu  
LyRW\\z2  
I*H($ a  
public void setNSplitter(int nCount) QVo>Uit   
{ 1\-r5e; BE  
nSplitter = nCount; x%T.0@
!8  
} 8~ u/gM  
} f-Zi!AGh>  
h}4yz96WD  

1C(sBU"  
/* +P%k@w#<Z  
**Utility.java !TO+[g!  
*/ z['2  
package NetFox; ~,.'
#=V  
) (0=w4  
DqHJ *x4  
public class Utility { aATNeAR  
C!)ZRuRv  
OxN[w|2\4  
public Utility() a] 7nK+N  
{ <."KejXg-  
kO4'|<  
Y-lTPR<Eq  
} ZP'0=  
m}6Jdt'|  
//线程睡眠 -`UOqjb]3  
public static void sleep(int nSecond) 2WC$r8E  
{ *U +<Hv`C  
try{ jcHyRR1R  
Thread.sleep(nSecond); lcK4 Uq\q  
} 0[E\h   
catch(Exception e) ~bsdy2&/q  
{ ^G4@cR.An  
e.printStackTrace (); z `jLKPP!=  
} f4$sH/ 2#v  
} R5&<\RI0  
kLc@U~M  
//日志 R]3j6
\  
public static void log(String sMsg) Yz#E0aTTA  
{ _ Y7Um  
System.err.println(sMsg); g)7@EU2  
} X0]{8v%  
~ +h4i'  
G|u)eW  
public static void log(int sMsg) [9G=x[  
{ "RgP!  
System.err.println(sMsg); AkCy C1  
} a(X V~o  
} l+j !CvtI  
,0{x-S0jX<  
<<R2 X1  
/* w|abaMam  
**TestMethod.java 7^tYtMm|U  
*/ YdyTt5-  
package NetFox; WtO@Kf:3GH  
d:"7Tw2v+  
yhrjML2K  
public class TestMethod { HuR774f[  
y?U@F/^}N  
FC WF$'cO  
public TestMethod() dh9@3. t  
{ ///xx/weblogic60b2_win.exe #}l$<7ZU  
try{ _}F_Q5)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }QBL{\E!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Xk\IO0GF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); uh`5:V  
fileFetch.start(); Swh\^/B8  
} E\TWPV'/  
catch(Exception e){e.printStackTrace ();} q3C  
4U~'Oa@p  
<KfR)7I$0a  
} 9WI5\`*"  
X ]W)D S  
hV:++g  
public static void main(String[] args) p=3t!3  
{ R+z'6&/ =I  
new TestMethod(); Kp^"<%RT  
} 5h|aX  
} ix$ ^1(  
点击下载更多相关资料