http断点续传简单实现（java)

/* LXEu^F~{u#  
**SiteFileFetch.java $^+K
R]\q  
*/ z?) RF[  
package NetFox; *$Wx*Jo  
import java.io.*; Qc =lf$  
import java.net.*; 8!fAv$g0  
A =Az[  
@.]K6qC  
public class SiteFileFetch extends Thread { ", Rw%_  
sT"tS>  
D!E 9@*Lf  
SiteInfoBean siteInfoBean = null; //文件信息Bean ]B.,7  
long[] nStartPos; //开始位置 .gsu_
N_v  
long[] nEndPos; //结束位置 KL\=:iWA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $=g.-F%*=  
long nFileLength; //文件长度 n YMf[kW  
boolean bFirst = true; //是否第一次取文件 Cq;K,B9  
boolean bStop = false; //停止标志 <IkD=X  
File tmpFile; //文件下载的临时信息 BMsy}08dQ  
DataOutputStream output; //输出到文件的输出流 wk <~Y 3u  
^VYZ%  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9C'+~<l  
public SiteFileFetch(SiteInfoBean bean) throws IOException r L|BkN  
{ mt6uW+t/
 
siteInfoBean = bean; wTuRo J  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bFdg'_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
d~b
H!P  
if(tmpFile.exists ()) mbG^fy'  
{ WF.$gBH"  
bFirst = false; 8_,wOkk_B  
read_nPos(); d.(]V2X.J  
} =d4',[O  
else }6{)Jv  
{ q>lkLHS  
nStartPos = new long[bean.getNSplitter()]; C]cT*B^  
nEndPos = new long[bean.getNSplitter()]; aZCZ/  
} 5N</Z6f'o  
n)7$x
YuH  
]be2jQx3  
\c^jaK5  
} O NzdCgY  
kk./-G  
3:gO7Uv  
public void run() ^>}[[:(6/  
{ [67f;?b  
//获得文件长度 hr"+0KeX  
//分割文件 ZjbG&oc  
//实例FileSplitterFetch XlcDF|?{.  
//启动FileSplitterFetch线程 Evgq}3  
//等待子线程返回 0JL6EL>_  
try{ k.f:nv5JO  
if(bFirst) iP\&fZY_  
{ I8wVvs;k  
nFileLength = getFileSize(); E6\~/=X=%  
if(nFileLength == -1) [?o vJ  
{ @9P9U`ZP  
System.err.println("File Length is not known!"); )s[S.`STz  
} H4",r5qw:  
else if(nFileLength == -2) :hdh$}y  
{ y(BLin!O.  
System.err.println("File is not access!"); MBrVh6z>  
} pY5HW2TsY|  
else p" W0$t.  
{ z`{zqP:  
for(int i=0;i<nStartPos.length;i++) l]=$<  
{ EF{'J8AQ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); d33Nx)No  
} 7027@M?A?  
for(int i=0;i<nEndPos.length-1;i++) `5jB|
r/  
{ dllf~:b  
nEndPos = nStartPos[i+1]; fszeJS}Dw  
} &=O1Qg=K  
nEndPos[nEndPos.length-1] = nFileLength; P[K T  
} tce8*:rNH  
} m
K/P4]9g  
7n]%`Yb  
nM}`H'0  
//启动子线程 $6%;mep  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9rc n*sm  
for(int i=0;i<nStartPos.length;i++) ^moIMFl  
{ Gl:T   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _jKVA6_E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), eTHh  
nStartPos,nEndPos,i); 6u3(G j@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >x0lSL0y  
fileSplitterFetch.start(); 7}85o J  
} m)w-mc  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -\v8i.w0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3`8xh9O  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $ !=:ES  
nEndPos = " + nFileLength); 1caod0gor  
// fileSplitterFetch[nPos.length-1].start(); [m&ZAq  
]a~LA7VHO  
LZ dNG\-  
//等待子线程结束 r}Av"  
//int count = 0; Av4E?@R  
//是否结束while循环 l~c>jm8.  
boolean breakWhile = false; Qj[O$L0 $  
4'|:SyOm  
J, >PLQAa  
while(!bStop) ;itg>\p3  
{ rmJ847%y`  
write_nPos(); HKw4}FC*  
Utility.sleep(500); a$&6a   
breakWhile = true; o:*i
T=l  
<7) 6*u  
Lxrn#Z eM  
for(int i=0;i<nStartPos.length;i++) 2 -8:qmP(  
{ fbkjK`_q  
if(!fileSplitterFetch.bDownOver) "b7C0NE  
{ IV*$U7~  
breakWhile = false; )C6 7qY  
break; ^<+heX  
} !qv;F?2 <g  
} W}3vY]  
if(breakWhile) uS,$P34^oy  
break; 3f8Z?[Bb@  
?QVI'R:Z
?  
KK|Jach  
//count++; VHNiTp  
//if(count>4) 4+bsG6i  
// siteStop(); h]9^bX__Z  
} 4tWI)}+ak  
E
+ 20->  
zf u7
8  
System.err.println("文件下载结束！"); _gh7_P^H=d  
} Z8UM0B=i  
catch(Exception e){e.printStackTrace ();} WQ`T'k#ESW  
} }C}_ I:=C  
Y.#+Yh[  
gp2)35  
//获得文件长度 e vuP4-[y  
public long getFileSize() ?>&Zm$5V  
{ 1fZ:^|\  
int nFileLength = -1; p
60D{UzU  
try{ l[k$O$jo  
URL url = new URL(siteInfoBean.getSSiteURL()); Q8i6kf!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;wrgpP3  
httpConnection.setRequestProperty("User-Agent","NetFox"); -}o;Y)  
") D!OW]  
@( l`_Wx  
int responseCode=httpConnection.getResponseCode(); FeLP!oS>  
if(responseCode>=400) 5{Wl(jwb  
{ RkzBn  
processErrorCode(responseCode); T:$_1I $  
return -2; //-2 represent access is error bk]|C!7$  
} ,vPF=wq  
w3D_ c~  
K-3 _4As  
String sHeader; HxaUVg0  
z^.0eP8\j  
y rk#)@/m  
for(int i=1;;i++) flqTx)xE  
{ 5@ug1F&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wn&2-m*a  
//Utility.log(in.readLine()); mZyTo/\0  
sHeader=httpConnection.getHeaderFieldKey(i); wQT'~'kL  
if(sHeader!=null) 6*7&X#gG  
{ _L":Wux  
if(sHeader.equals("Content-Length")) bSfQH4F  
{ "Cb<~Dy  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6tguy  
break; c^y 1s*  
} _rd{cvdR  
} -}@9lhS,  
else >Fz$DKr[  
break; Rd)QVEk>SD  
} Hik[pVK@  
} Cx[4 /~_<  
catch(IOException e){e.printStackTrace ();}  s25012  
catch(Exception e){e.printStackTrace ();} V_!i KEU  
q]x@q  
F*f)Dv$p  
Utility.log(nFileLength); eORt qX8*  
KXJHb{?  
-bwl~3ZTi  
return nFileLength; &^.'g{\Y  
} P*>V6SK>b  
W=
!f  
9[`6f8S_$  
//保存下载信息（文件指针位置） :9}*p@  
private void write_nPos() |wDCIHzQ  
{ n[@Ur2&)  
try{ 9!LAAE`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jJ|;Nwm<[  
output.writeInt(nStartPos.length); #^Y,,GA  
for(int i=0;i<nStartPos.length;i++) :"4~VDu  
{ }MNm>3  
// output.writeLong(nPos); cF6|IlhO  
output.writeLong(fileSplitterFetch.nStartPos); iX=*qiVX  
output.writeLong(fileSplitterFetch.nEndPos); 
Qxwe,:  
} 5WUrRQ?E  
output.close(); Nu'rn*Y_  
} Q*he%@w  
catch(IOException e){e.printStackTrace ();} y_6HQ:  
catch(Exception e){e.printStackTrace ();} ?@_dx=su  
} rfjQx]3pB  
O%r<I*T^r  
>KE(%9y~  
//读取保存的下载信息（文件指针位置） LdOB[W  
private void read_nPos() Dng^4VRd  
{ >qE$:V"_5  
try{ GOt@x9%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /?sV\shy  
int nCount = input.readInt(); [#:k3aFz  
nStartPos = new long[nCount]; mIyaoIE|$  
nEndPos = new long[nCount]; F<$&G'% H  
for(int i=0;i<nStartPos.length;i++) ?Rdi"{.wI  
{ y;;@T X  
nStartPos = input.readLong(); <x/&Ml+  
nEndPos = input.readLong(); %9j]N$.V  
} $Ix^Rm9c  
input.close(); LE;c+(CAU  
} jAu/] HZx  
catch(IOException e){e.printStackTrace ();} c&Dy{B!  
catch(Exception e){e.printStackTrace ();} ps2C8;zT  
} @bZb#,n]  
PJ'l:IU  
B4kIcHA  
private void processErrorCode(int nErrorCode) O'k"6sBb  
{ b#sO1MXv  
System.err.println("Error Code : " + nErrorCode); ZM"t.  
} :z[SI{Y  
>a<;)K^1  
M<SZ7^9<  
//停止文件下载 q bo`E!K  
public void siteStop() | !Knd ^}  
{ wegBMRQVp  
bStop = true; zIu1oF4[  
for(int i=0;i<nStartPos.length;i++) H_{Yr+p  
fileSplitterFetch.splitterStop(); ,D8Tca\v  
BEw(SQH  
?IK[]=!  
} ||hd(_W8  
} C-8@elZ1  
//负责部分文件的抓取 YJ6Xq||_  
**FileSplitterFetch.java k@?<Aw8_X  
*/ :0J;^@  
package NetFox; 5lT lZRH1  
PH6uP]  
2'D2>^os  
import java.io.*; j9%=^ZoQj  
import java.net.*; {'/8{dS  
zR%#Q_  
JH 8^ZP:d'  
public class FileSplitterFetch extends Thread { r;-\z(
h  
@ Fu|et  
CGQ`i  
String sURL; //File URL 37VSE@Z+  
long nStartPos; //File Snippet Start Position .k}h'nE  
long nEndPos; //File Snippet End Position )/UkJ/}j  
int nThreadID; //Thread's ID Qk((H~I}  
boolean bDownOver = false; //Downing is over d;`JDT  
boolean bStop = false; //Stop identical dI`b AP;\  
FileAccessI fileAccessI = null; //File Access interface y@F{pr+dA  
!^y'G0  
:>|[ o&L  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ).\%a h  
{ `,J\E<4J  
this.sURL = sURL; L9T|*?||  
this.nStartPos = nStart; _s^sZ{'2_  
this.nEndPos = nEnd; /0
A}N$?>:  
nThreadID = id; V[#jrwhA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7a2uNt,X  
} ]'hz+V31%  
zFlW\wc  
|1#*`2j\=9  
public void run() sq_ f[!  
{ .RdnJ&K*  
while(nStartPos < nEndPos && !bStop) zMtx>VI
 
{ LKhUqW  
y:mXv<g  
V V<Zl  
try{ Z\n nVM=  
URL url = new URL(sURL); bO9X;}\6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |(]XZ!{  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5~v({R.  
String sProperty = "bytes="+nStartPos+"-"; O9bIo]B  
httpConnection.setRequestProperty("RANGE",sProperty); kIyif7  
Utility.log(sProperty); m
k}8Cu4  
1$4dzI()  
->d3FR  
InputStream input = httpConnection.getInputStream(); n*uT  
//logResponseHead(httpConnection); #}o*1  
fnB[b[  
:M3Fq@w=  
byte[] b = new byte[1024]; *&XOzaVU  
int nRead; g/eE^o~;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  Hi#hf"V  
{ R,8;GS42  
nStartPos += fileAccessI.write(b,0,nRead); nPE{Gp) }  
//if(nThreadID == 1) T< D&%)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nGq{+ G  
} `#R[x7bA1  
`KB;3L  
 t
mKHT  
Utility.log("Thread " + nThreadID + " is over!"); L\aG.\  
bDownOver = true; }gete'I  
//nPos = fileAccessI.write (b,0,nRead); r[K%8Y8`  
} wZ0RI{)s'  
catch(Exception e){e.printStackTrace ();} X3@Uih}|  
} `fS$@{YI_  
} ]@0C1r  
)1N~-VuT  
Dr)B0]KG  
//打印回应的头信息 f["c,,[  
public void logResponseHead(HttpURLConnection con) kZ$2Uss  
{ :pq+SifP  
for(int i=1;;i++) ~m3Q^ue  
{ 1aDx 6Mq  
String header=con.getHeaderFieldKey(i); \8g'v@$wG  
if(header!=null) NYw>Z>TD8c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1R-WJph  
Utility.log(header+" : "+con.getHeaderField(header)); g%TOYZr!X  
else 3?5JY;}h>"  
break; A`71LV%  
} E6XDn`:  
} IK1'" S|  
Ym%XCl  
VkFMr8@|  
public void splitterStop() 
{^8?fJ/L  
{ CVE(N/&b  
bStop = true; |yS  %  
} KrdEB0qh  
s@zO`uBc  
$7"
Y/9Y  
} nr&bpA/  
# ~Doz7~  
;6:9EEd  
/* xpX<iT>5u  
**FileAccess.java __!LTpp  
*//文件访问(定位，写) Me79:+d  
package NetFox; ZLP/&`>8  
import java.io.*; ClG\Kpirh  
j"K^zh  
p4V*%A&w  
public class FileAccessI implements Serializable{ q #mBNe62p  
_K}q%In  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;4l8Qg 7  
RandomAccessFile oSavedFile; M287Z[  
long nPos; r0!')?#Z  
>"8;8Ev  
hr;^.a^
  
public FileAccessI() throws IOException ]DKRug5  
{ EsGf+-}|!0  
this("",0); U0t|i'Hx  
} v^ "qr?3V  
").gPmC  
"MU-&**  
public FileAccessI(String sName,long nPos) throws IOException \_WR:?l  
{ Vbt!, 2_)  
oSavedFile = new RandomAccessFile(sName,"rw"); =* G3Khz!  
this.nPos = nPos; 7mq&]4-G  
oSavedFile.seek(nPos); d\uN  
} :`e#I/,  
b3EGtC}^  
t5%cpkgh4  
public synchronized int write(byte[] b,int nStart,int nLen) T:u>7
?8o  
{ +@=V}IO  
int n = -1; x(._?5  
try{ Ly&+m+Gwu  
oSavedFile.write(b,nStart,nLen); ;+<IWDo  
n = nLen; GA[Ebzi  
} '{cSWa| #  
catch(IOException e) @oE 5JM  
{ `mzlOB  
e.printStackTrace (); 5afD;0D5TI  
} Xd=KBB[r?  
`p
&[b]b  
<mQXS87  
return n; i}VF$XN  
} Ss+F  
}9+;-*m/  
N$6e KJ]  
} 9a=Ll]=\  
x=t
(#R m  
l)9IgJ|<b  
/* <%m YsaM  
**SiteInfoBean.java >E>yA d  
*/ !HvA5'|:}  
package NetFox; k5I;Y:~`  
SI=$s>1  
P9/ (f$=  
public class SiteInfoBean { <{isWEW9]3  
6;Z-Y>\c  
$Z:O&sD{  
private String sSiteURL; //Site's URL dymq Z<  
private String sFilePath; //Saved File's Path 3[ xdls  
private String sFileName; //Saved File's Name XVqOiv)  
private int nSplitter; //Count of Splited Downloading File KLyRb0V  
{V6&((E8  
t>[W]%op  
public SiteInfoBean() _~z oMdT!  
{//nSplitter的缺省值为5 jVQy{8{G  
//default value of nSplitter is 5 w}ji]V}  
this("","","",5); B&]`OO>O  
} aUaeK(x:H  
AJ\&>6GZ(b  
ib=)N)l  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J8qFdNK  
{ h[W`P%xZ  
sSiteURL= sURL; %L=e%E=m  
sFilePath = sPath; l=E86"m  
sFileName = sName; aV\i3\da  
this.nSplitter = nSpiltter; 50cVS)hG6d  
.d<K`.O;  
|J-X3`^\H  
} 24 [KGp  
\O5L#dc#  
S(gr>eC5  
public String getSSiteURL() 5#GMp  
{ #`VAw ) eV  
return sSiteURL; 731Lz*IFg  
} K!6T8^JH  
hY`<J]-'`  
]3LLlXtK[  
public void setSSiteURL(String value) ZSuoD$~k[  
{ TxJk.
c  
sSiteURL = value; OG5{oH#K  
} t#^Cem<  
1SExlU  
tu\XuDky  
public String getSFilePath() #_DpiiS,.Q  
{ Nx 42k|8  
return sFilePath; g88k@<Y  
} jZA1fV  
tm~9XFQ<  
}j/\OY _&  
public void setSFilePath(String value) ;/Hr ZhOE  
{ "*bLFORkq'  
sFilePath = value; K(+=V)'Dz  
} U
D-+BUV  
|{#St-!-7  
Ok!P~2J  
public String getSFileName() ]64Pk9z=  
{ tx09B)0  
return sFileName; ji/`OS-iq  
} }F>RIjj  
s~Eo]e  
k=s^-Eiu  
public void setSFileName(String value) ``/L18  
{ % !@E)%d0  
sFileName = value; Cog}a  
} o<nM-"yWb  
{8m&Z36E  
Qw0k-t0=4  
public int getNSplitter() 1S?~c25=h  
{ *y4DK6OFe  
return nSplitter; xm{?h,U,  
} P.Ntjz/B  
9K$ x2U  
zqA>eDx  
public void setNSplitter(int nCount) HhynU/36  
{ 2 5~Z%_?  
nSplitter = nCount; \l!+l  
} /nO_e  
} T
zKM~a#  
&& ]ix3  
WSozDNF!'f  
/* lV'?X%  
**Utility.java bc(MN8b]j  
*/ -C2!`/
U  
package NetFox; #w;"s*  
n*[ZS[I  
!j$cBf4  
public class Utility { 02,t  
>#h,q|B  
Yi9Y`~J  
public Utility() [[[C`H@  
{ X5o*8Bg4M  
.i;.5)shsu  
LH54J;7Y  
} QvbH " 7  
"}X+vd``  
//线程睡眠 vd%AV(]<LJ  
public static void sleep(int nSecond) "nz\YQdg  
{ r5gqRh}+  
try{ '-"[>`[q  
Thread.sleep(nSecond); Z`kVyuQ  
} oaj.5hM  
catch(Exception e) NnAIL;WS  
{ E:qh}wY  
e.printStackTrace (); kI"
9T`owR  
} !>F70  
} GbLHzw  
^x0N]/  
//日志 E]Mx<7;\.  
public static void log(String sMsg) ICz:>4M-dn  
{ `%\CO`  
System.err.println(sMsg); #j Tkz  
} T`^Jws{;7  
e#hg,I  
O1\4WG%  
public static void log(int sMsg) 5@
RcAQb:  
{ * K$U[$s  
System.err.println(sMsg); *-ys}sX  
} (g@X.*c8  
} %f<>Kwr`2  
2=?3MXcjy  
fln[Q2zl  
/* /SJ><  
**TestMethod.java #|T"6jJaQ  
*/ qUfoEpW2=6  
package NetFox; GLIY!BU<C  
)&E]  
 3*Q=)}  
public class TestMethod { yMdu Zmkc  
dA~_[x:Z  
u"zR_CzYc  
public TestMethod() aEzf*a|fSV  
{ ///xx/weblogic60b2_win.exe or#] ![7N  
try{ JFI*Pt;X9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kB?/_a`]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1>[#./@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ep(xlHTv  
fileFetch.start(); mxEe -q  
} .<vXj QE  
catch(Exception e){e.printStackTrace ();} _#
Hd2h  
>NPK;Vu  
.,6o):  
} HT/!+#W.  
,8zJD&HMx  
i%!<9D~n  
public static void main(String[] args) [PN
2^  
{ 6&]Z'nW0k  
new TestMethod(); Vs
TgK  
} onmpMU7w  
} =?W7OV^BE  
点击下载更多相关资料