http断点续传简单实现（java)

/* yG%<LP2p@f  
**SiteFileFetch.java p#6V|5~8  
*/ >~)IsQ*%  
package NetFox; n>["h2  
import java.io.*; gyx4='Q  
import java.net.*; FaVeP%v  
wNt-mgir-Q  
2ij
/!  
public class SiteFileFetch extends Thread { [tEHr  
kV$$GLD\  
RLtIn!2OU  
SiteInfoBean siteInfoBean = null; //文件信息Bean [Dou%\  
long[] nStartPos; //开始位置 #'?gMVSk  
long[] nEndPos; //结束位置 NIascee  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7x ?2((  
long nFileLength; //文件长度 JRT,%;*,  
boolean bFirst = true; //是否第一次取文件 <z+b88D  
boolean bStop = false; //停止标志 !?%'Fy6t  
File tmpFile; //文件下载的临时信息 R]8^ @i1  
DataOutputStream output; //输出到文件的输出流 eKj'[2G@/  
IX]K"hT  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O"Ua|8  
public SiteFileFetch(SiteInfoBean bean) throws IOException |DZ3=eWZ  
{ ?5
yj</W  
siteInfoBean = bean; R:}u(N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {?zbrgQ<Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); sHwn,4|iY  
if(tmpFile.exists ()) wWU5]v  
{ N)rf/E0  
bFirst = false; C"=^(HU  
read_nPos(); acdWU"<  
} /Wqx@#  
else 5HAIK
c  
{ 83ajok4E  
nStartPos = new long[bean.getNSplitter()]; lxvRF93a.  
nEndPos = new long[bean.getNSplitter()]; _a e&@s1  
} 6QC=:_M;  
`T \"B%  
:1O1I2L0  
,*w  
} ,& ^vc_}  
%
^C.e*  
5cza0CriJ  
public void run() hDf|9}/UQd  
{ `Rc7*2I)l  
//获得文件长度 uKBSv*AM  
//分割文件 \f AL:mJ  
//实例FileSplitterFetch
uDZ$'a  
//启动FileSplitterFetch线程 jW G=k#WN  
//等待子线程返回 (DW[#
2\.  
try{ c T!L+zg  
if(bFirst) DrTo")T  
{ )E2^G)J$W  
nFileLength = getFileSize(); Q.8)_w  
if(nFileLength == -1) g+-=/Ge  
{ t#0/_tD  
System.err.println("File Length is not known!"); {0#p,l  
} us^2Oplq<  
else if(nFileLength == -2) >WsRCBA  
{
DjX*2O  
System.err.println("File is not access!"); TyCMZsvM,  
} ;BR`}~m  
else *vss  
{ ':v@Pr|  
for(int i=0;i<nStartPos.length;i++) z>f>B6  
{ "F*'UfOwrZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <u"h'e/oW_  
} #h 4`f  
for(int i=0;i<nEndPos.length-1;i++) qQ_o>+3VAy  
{ vIoV(rc+  
nEndPos = nStartPos[i+1]; $=?CW(  
} ^r7-|  
nEndPos[nEndPos.length-1] = nFileLength; l9J]<gG  
} 0wzq{~\{=_  
} I#]$H#}Av  
QX*HvT  
@CSTp6{y  
//启动子线程 nr#DE?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 88dq8T4  
for(int i=0;i<nStartPos.length;i++) r2EIhaGF;  
{ @+v;B:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8%UI<I,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rsp?N{e  
nStartPos,nEndPos,i); P8JN m"C  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ba$Ibq,r/  
fileSplitterFetch.start(); dnby&-+T  
} CaZ{UGokL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fR>(b?C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); EH'?wh|Yp  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2Et7o/\<  
nEndPos = " + nFileLength); ~ituPrH%<  
// fileSplitterFetch[nPos.length-1].start(); GRanR'xG  
p7"o:YSQ  
$lj1924?^  
//等待子线程结束 QY<{S&k9  
//int count = 0; sLV bF
N`  
//是否结束while循环 g+ik`q(ge  
boolean breakWhile = false; zS*X9|p  
{]\QUXH  
xGQ958@  
while(!bStop) Q?GmSeUi  
{ .)W'{2J-  
write_nPos(); aDx{Q&  
Utility.sleep(500); Tc6H%itV  
breakWhile = true;  0u4:=Z}W  
.[1"Med J  
<;d?E%`  
for(int i=0;i<nStartPos.length;i++) C:n55BE9  
{ 1.]Py"@:  
if(!fileSplitterFetch.bDownOver) DRLX0Ml]\  
{ %@Nuzdp  
breakWhile = false; kfo, PrW`A  
break; VJMn5v[V  
} Kc=&jCn  
} sKhX0,s&  
if(breakWhile) iHo2=Cz  
break; f1;Pzr  
DWep5$>&K  
uE~? 2G  
//count++; I U/HYBJH  
//if(count>4) d%Zt]
1$  
// siteStop(); Qo{Ez^q@J  
} M0<gea\ =  
Nhv~f0  
%|[+\py$Q  
System.err.println("文件下载结束！"); tL1"Dt>  
} Ti }Ljp^O  
catch(Exception e){e.printStackTrace ();} tY<D\T  
} d-g&TSGd  
`Td
0R!  
_f%Wk>
A4  
//获得文件长度 o'@VDGS`  
public long getFileSize() <">tB"="b  
{ \$ L2xd  
int nFileLength = -1; w{3 B  
try{ le%_[/_I|  
URL url = new URL(siteInfoBean.getSSiteURL()); s5>=!yX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); az~4sx$+}  
httpConnection.setRequestProperty("User-Agent","NetFox"); r{.DRbn  
?<\K!dA  
zp>q$e40  
int responseCode=httpConnection.getResponseCode(); [^B04
x@  
if(responseCode>=400) 0t<]Uf  
{ !L"3Otd  
processErrorCode(responseCode); RQ#gn  
return -2; //-2 represent access is error MNNPBE  
} A/Kw"l>  
]Kb  
8 ~.|^no  
String sHeader; s8.OL_e  
[>+(zlK"  
%zQME6WELz  
for(int i=1;;i++) 6|3$43J,F  
{ oop''6`C%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {~ ZSqd  
//Utility.log(in.readLine()); A.m#wY8  
sHeader=httpConnection.getHeaderFieldKey(i); g?!vRid@S  
if(sHeader!=null) pc<")9U%/  
{ 7f_4qb8  
if(sHeader.equals("Content-Length")) w1EYXe  
{ $;Lb|~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9:CJl6~N)#  
break; ?c0OrvM  
} TLzg*  
} P9vN5|"M  
else 703=.xj  
break; 7%L%dyN  
} rxjMCMF  
} utKtxLX"  
catch(IOException e){e.printStackTrace ();} x F7C1g(  
catch(Exception e){e.printStackTrace ();} qYc]Y9fi  
JzMPLmgG/  
RekTWIspT/  
Utility.log(nFileLength); :Eq=wbAw  
q
lmz@kTb  
fQc2K|V  
return nFileLength; J:Uf}!
D  
} 48Y5ppcS  
gP1~N^hke]  
Y15KaoK?  
//保存下载信息（文件指针位置） q}*"0r  
private void write_nPos() LGZ5py=xb  
{ |3W\^4>,  
try{ ivsp):W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZvEcExA-  
output.writeInt(nStartPos.length); -Czq[n=0(  
for(int i=0;i<nStartPos.length;i++) a
W]!$  
{ 9B")/Hz_  
// output.writeLong(nPos); ZYZQ?
FN  
output.writeLong(fileSplitterFetch.nStartPos); F;Ms6 "K  
output.writeLong(fileSplitterFetch.nEndPos); G=a.Wff  
} WJCEiH  
output.close(); gBz$RfyF  
} gE%{#&*  
catch(IOException e){e.printStackTrace ();} rXXIpQRi$S  
catch(Exception e){e.printStackTrace ();} 3UgusH3  
} U;o[>{L   
5f2ah4 g  
J"'2zg1&  
//读取保存的下载信息（文件指针位置） #<|5<U  
private void read_nPos()
"ut:\%39.  
{ h"/FqO  
try{ Bi2be$nV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9.ZhkvR4A  
int nCount = input.readInt(); ei'=%r8~  
nStartPos = new long[nCount]; JViglO1\  
nEndPos = new long[nCount]; MJ'|$b}  
for(int i=0;i<nStartPos.length;i++) e_s9E{(  
{ yXY8 oE  
nStartPos = input.readLong(); l#%Y]1*  
nEndPos = input.readLong(); Jjik~[<q:  
} jD0^,aiG  
input.close(); eB/3MUz1  
} fMwJwMT8  
catch(IOException e){e.printStackTrace ();} >!E:$;i@  
catch(Exception e){e.printStackTrace ();} *gHOH!K,S  
} T*\'G6e  
+Es3iE @  
?v#t{e0eQ  
private void processErrorCode(int nErrorCode) .Xo, BEjE/  
{ Kr=DoQ."d8  
System.err.println("Error Code : " + nErrorCode); Zi$a6  
} 6VolTy@(x  
sq*R)cZ  
1mL--m'r  
//停止文件下载 g6Qzkvw)  
public void siteStop() M
p?Ev.  
{ `>rdn*B  
bStop = true; ~zRUJ2hD!  
for(int i=0;i<nStartPos.length;i++) v;el= D  
fileSplitterFetch.splitterStop(); ?YXl.yj  
.,l?z  
vkE6e6,Qc  
} 8
_U*_I7(  
} U?>P6p  
//负责部分文件的抓取 mn*.z!N=  
**FileSplitterFetch.java ~yt+xWV  
*/ {#=q[jVi%1  
package NetFox; it
X<!  
-DX|[70  
}pPxN@X  
import java.io.*; PAH; +  
import java.net.*; )oG_x{  
M=26@ n  
(BMFGyE3  
public class FileSplitterFetch extends Thread { @`$8rck`  
cc.zC3Hs3  
vhTte |(  
String sURL; //File URL u` `FD  
long nStartPos; //File Snippet Start Position h<6@&yzp  
long nEndPos; //File Snippet End Position uV52ko,  
int nThreadID; //Thread's ID zvdtP'&uj  
boolean bDownOver = false; //Downing is over ~k+-))pf  
boolean bStop = false; //Stop identical epW
;]> l  
FileAccessI fileAccessI = null; //File Access interface vxZvK0b620  
o{ \cCZ"  
+x-n,!(  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  -"\z|OQ  
{ B:&/*HU  
this.sURL = sURL; fi:Z*-  
this.nStartPos = nStart; t{Q9Kv  
this.nEndPos = nEnd; op"RrZAZBT  
nThreadID = id; OY51~#BF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 lk%rE  
} Hl?\P6  
$a(wM1S4  
v\c.xtjI5x  
public void run() kJlRdt2  
{ f<!eJO:<'  
while(nStartPos < nEndPos && !bStop) i=o<\{iV:  
{ tlCgW)<?  
xx#;)]WT  
;I:jd")  
try{ `Q,moz  
URL url = new URL(sURL); x a7x 2]~-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SH<Nt[8C  
httpConnection.setRequestProperty("User-Agent","NetFox"); X@\rg}kP  
String sProperty = "bytes="+nStartPos+"-"; )C<c{mjk(  
httpConnection.setRequestProperty("RANGE",sProperty); )4D |sN  
Utility.log(sProperty); |bO}|X  
bv4lgRE6Y  
b9%hzD,MR  
InputStream input = httpConnection.getInputStream(); B7fURL Rqr  
//logResponseHead(httpConnection); 3EI$tP@4  
Ih{(d O;  
3(}W=oI  
byte[] b = new byte[1024]; J3oH^  
int nRead; 3*/y<Z'H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @@# ^G8+l  
{ K!).QB'  
nStartPos += fileAccessI.write(b,0,nRead); "/S-+Ufn  
//if(nThreadID == 1) 2x"&8Bg3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dTB^6>H  
} G9 ;X=
c  
O< v0{z09*  
ry*b"SO  
Utility.log("Thread " + nThreadID + " is over!"); (ye1t96  
bDownOver = true; P@`@?kMU  
//nPos = fileAccessI.write (b,0,nRead); ?.LS_e_0  
} [W,Ej  
catch(Exception e){e.printStackTrace ();} [GyW1-p33w  
} kOfbO'O9  
} }:])1!a  
z|Q)^  
||;V5iR
:  
//打印回应的头信息 2TXrVaM  
public void logResponseHead(HttpURLConnection con) `1=n H/E  
{ Kyq/'9`  
for(int i=1;;i++) |e!%6Qq3  
{ `aD~\O  
String header=con.getHeaderFieldKey(i); W4%I%&j  
if(header!=null) SP?~i@H  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z\Hg@J&#  
Utility.log(header+" : "+con.getHeaderField(header)); mSm:>hBd  
else l+HmG< P  
break; V^
;2u  
} }F!tM"X\  
} ,bzE`6  
e{EKM4  
Q'5]E{1<'n  
public void splitterStop() <tXk\cOg  
{ ?41bZ$j  
bStop = true; G8z.JX-7g  
} bWWZGl9  
5, "  
B6ee\23  
} bca4'`3\|  
sB`.G  
yhm
6%  
/* TS4Yzq,f  
**FileAccess.java cQ}
3? v  
*//文件访问(定位，写) >n$V1U&/  
package NetFox; CGw,RNV  
import java.io.*; o|`[X'  
K Q^CiX  
9UDanj P  
public class FileAccessI implements Serializable{ ^E~F,]dV=  
!aQb Kp  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o-I:p$B-  
RandomAccessFile oSavedFile; CCDU5l$$  
long nPos;
['m7Wry  
"`Q&s  
B']-4X{SGa  
public FileAccessI() throws IOException Fz11/sKz  
{ E<RPMd @a  
this("",0); UahsX  
} U45kA\[bZ  
)iX2r{  
ibH!bS{  
public FileAccessI(String sName,long nPos) throws IOException 9]C%2!Ur,  
{ AjVX  
oSavedFile = new RandomAccessFile(sName,"rw"); _=Z?5{7S>  
this.nPos = nPos; ~Y/:]&wF  
oSavedFile.seek(nPos); uwl_TDc>%  
} ylm #Xa  
tn{YIp  
U7#C.Z  
public synchronized int write(byte[] b,int nStart,int nLen) ff&jR71E  
{ &&% oazR=  
int n = -1; mF:Pplf<  
try{ CY~ S{w  
oSavedFile.write(b,nStart,nLen); <
@Z`<T6  
n = nLen; n g%~mt  
} S86,m=  
catch(IOException e) po\(O8#5U  
{ Um^4[rl:#g  
e.printStackTrace (); Ptm=c6H('  
} t!-\:8n  

iC{(vL0P+  
KFgq3snH  
return n; ?;VsA>PV  
} &V|kv"Wwj  
b)eoFc)lc  
nW)?cQ I  
} Q5c3C&$6  
GKc?  
Q6T"8K/  
/* X1HEeJ|  
**SiteInfoBean.java [tT_ z<e`  
*/ oam$9 q  
package NetFox; tD*k   
ebn3r:IU-  
=
r4sF!g  
public class SiteInfoBean { IL go:xQ  
0W0GSDx  
r+8)<Xt+p  
private String sSiteURL; //Site's URL B}S+/V` Y5  
private String sFilePath; //Saved File's Path Sg
$\H  
private String sFileName; //Saved File's Name mPU}]1*p  
private int nSplitter; //Count of Splited Downloading File qfG:vTm  
R#3zGWr~  
^&D5J\][  
public SiteInfoBean() idB1%?<  
{//nSplitter的缺省值为5 E mg=,  
//default value of nSplitter is 5 !E&l=*lM.  
this("","","",5); h/oun2C  
} Nyt*mbd5 {  
^KdT,
^6T  
(/2rj[F&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R%4Yg(-Q  
{ z
.Z  
sSiteURL= sURL; ZJF"Yo  
sFilePath = sPath; 2 431v@  
sFileName = sName; 1d~d1Rd  
this.nSplitter = nSpiltter; b}fC' h  
=/}Rnl+c  
oKYa?  
} rrR"2WuGO  
Y(t/=3c[  
"f8,9@  
public String getSSiteURL() u(FOSmNkN  
{ kQe<a1 8  
return sSiteURL; 4evNZ Q  
} e,{k!BXU#'  
*Lxt{z`9  
[0qswsV  
public void setSSiteURL(String value) z{&Av  
{ KB
^8Z@(+  
sSiteURL = value; OwEV$Q  
} VQ,5&-9Y3  
!?_CIt$p  
.71ZeLv*  
public String getSFilePath() dH.Fb/7f  
{ ZV:df 6S  
return sFilePath; @54$IhhT~  
} )5n0P Zi  
p2Gd6v.t  
-<k)|]8  
public void setSFilePath(String value) T[^&ZS]s  
{ :-#7j} R&  
sFilePath = value; R<_VWPlj  
} ]KEE+o  
IP$eJL[&D"  
`q\F C[W  
public String getSFileName() dl[%C6  
{ u$[&'D6  
return sFileName; 0LXu!iix  
} s0]ZE\`H>  
wl%ysM|x  
;hODzfNkS  
public void setSFileName(String value) -W.-m2:1  
{ w)* H&8h@  
sFileName = value; 4"Qb^y  
} fd #QCs  
FWU>WHX  
@`+\v
mfD  
public int getNSplitter() Tc!n@!RA|  
{ _VjaTw8iM  
return nSplitter; }"nm3\Df  
} 5D=U.UdR  
6T+ym9  
Nt]nwae>A  
public void setNSplitter(int nCount) ;7EeRM*  
{ a#+$.e5  
nSplitter = nCount; Y@k=m )zE  
} .b`8
+  
} R\X;`ptT  
?D7zty+}^  
h4itXJy52B  
/* bC"h7$3  
**Utility.java i;/;zG^=_  
*/ )(
yaX  
package NetFox; Y@q9  
mJd8?d  
=`>ei  
public class Utility { },}g](!m  
Vv5T(~  
kI04<!  
public Utility() yK9EH
J$  
{ yxT}hMa  
a
%a0/!U[  
3TeRZ=2:*x  
} i9rv8"0>  
v9,cL.0&  
//线程睡眠 gaNe\  
public static void sleep(int nSecond) {|OXiR
m'  
{ a(|0'^  
try{ FIAmAZH}_  
Thread.sleep(nSecond); 8 l= EL7  
} A7XA?>~+|  
catch(Exception e) w'_|X&@H  
{ wpC.!T  
e.printStackTrace (); )+Z.J]$O-  
} ;.xKVH/@  
} 5kWzD'!^  
0|K<$e6IH  
//日志 90Sras>F  
public static void log(String sMsg) P.k>6T<U>  
{ ]Lg~I#/#  
System.err.println(sMsg); )MTf  
} B<Cg_C  
m~W[,7NE0&  
qe?Ns+j<d  
public static void log(int sMsg) t5i58@{~  
{ [4bE"u  
System.err.println(sMsg); S=`$w  
} 3m4 sh~  
} snu?+*6  
Ay^P#\VZ  
Btr>ek  
/* 8KkN "4'  
**TestMethod.java _*{Lha  
*/ 8'qlg|{!~  
package NetFox; 3fX_XH1Q  
R47y/HG,  
a+O?bO  
public class TestMethod { lt]&o0>  
2ve<1+V_  
z%JN|5  
public TestMethod() n_Y7*3/b-o  
{ ///xx/weblogic60b2_win.exe x;} 25A|  
try{ umAO&S.+M  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X&rsWk  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?|}qT05  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2 w! 0$  
fileFetch.start(); Ly2!(,FB.  
} :P%?!'M  
catch(Exception e){e.printStackTrace ();} ;.=0""-IF  
hgDFhbHtd6  
?8< =.,r  
} L*4=b (3  
*A}td8(  
~ oq.yn/1  
public static void main(String[] args) 7(C)vtEO:  
{ saQo]6#  
new TestMethod();
rf'A+q  
} mF4OLG3L0  
} eOXu^M>:F  
点击下载更多相关资料