http断点续传简单实现（java)

/* %O`@}Tg  
**SiteFileFetch.java pX%:XpC!h  
*/ n%3!)/$  
package NetFox; | In{5Ek  
import java.io.*; l\Ozy  
import java.net.*; egu{}5  
G!j9D  
r~,y
3L6ic  
public class SiteFileFetch extends Thread { /V,xSK9.&  
_=$~l^Y[  
,1ev2T  
SiteInfoBean siteInfoBean = null; //文件信息Bean .RpJZ[E  
long[] nStartPos; //开始位置 8Qg{@#Wr  
long[] nEndPos; //结束位置 4|PWR_x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 jC&fnt,O  
long nFileLength; //文件长度 Ql{#dcRx  
boolean bFirst = true; //是否第一次取文件 6!_Wo\_%  
boolean bStop = false; //停止标志 5&8E{YXr  
File tmpFile; //文件下载的临时信息 {N~mDUoJ|  
DataOutputStream output; //输出到文件的输出流 TKnWhB/J  
LtRRX@qJw  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |jIHgm  
public SiteFileFetch(SiteInfoBean bean) throws IOException }<WJR Y6j  
{ 3l=q@72  
siteInfoBean = bean; <);q,|eh2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Wx0i_HFR  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]0D-g2!|A  
if(tmpFile.exists ()) `%Fp'`ZM$8  
{ QYbB\Y  
bFirst = false; n~62
9&  
read_nPos(); qy|bOl  
} \d"\7SA  
else ;^/ruf[t  
{ ^8&}Nk[j  
nStartPos = new long[bean.getNSplitter()]; 2 `AdNt,  
nEndPos = new long[bean.getNSplitter()]; d>f;N+O%  
} ^ =C>  
Onx6Fy]L  
k^}[+IFJ  
=G}a%)?As\  
} =>'8<"M5z  

2mEqfy  
cB,^?djJ3  
public void run() _4>DuklH,  
{ 437Wy+Q|e  
//获得文件长度 .OJGo<#$f  
//分割文件 k5< n:
dS  
//实例FileSplitterFetch tz]0F5  
//启动FileSplitterFetch线程 )>ML7y  
//等待子线程返回 uL)MbM]  
try{ h.tj8O1  
if(bFirst) "\*)KH`C  
{ :Ak^M~6a5  
nFileLength = getFileSize(); ;Pk"mC  
if(nFileLength == -1) $2Wk#F2c=  
{ "22./vWV|i  
System.err.println("File Length is not known!"); vGyQ306  
} Q%O9DCi  
else if(nFileLength == -2) #m|el@)  
{ Qb@j8Xa4[  
System.err.println("File is not access!"); MNs<yQ9I'  
} u8 k^\Do  
else 1tXc7NA<  
{ ^U~Er'mT  
for(int i=0;i<nStartPos.length;i++) rv[BL.qV  
{ @Xoh@:j\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); AkW,Fp1e  
} _,^f,W
O~  
for(int i=0;i<nEndPos.length-1;i++) L^e*_q2d:>  
{ &K]|{1+  
nEndPos = nStartPos[i+1]; IRM jL.q  
} ub 2'|CYw  
nEndPos[nEndPos.length-1] = nFileLength; ;s3@(OnjZ  
} 08
:K9zr  
} gS(JgN  
pjO  
T2-x1Sw_  
//启动子线程 #~j$J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4oF,;o+v\4  
for(int i=0;i<nStartPos.length;i++) TPb&";4ROf  
{ 'q9Ejig  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TJ>YJD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &h[)nD  
nStartPos,nEndPos,i); |\B\IPs{%'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VFV8ik)  
fileSplitterFetch.start(); F4(;O7j9  
} gu3)HCZ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !5+9~/;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Iy5W/QK6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XF{2'x_R  
nEndPos = " + nFileLength); IAd^$9  
// fileSplitterFetch[nPos.length-1].start(); @W+8z#xr'  
p"\-iY]  
f].z.  
//等待子线程结束 )P1NX"A  
//int count = 0; ^R\5'9K!  
//是否结束while循环 8Pom^QopK  
boolean breakWhile = false; HH!SqkwT  
@TKQ_7BcB  
jbOzbxR?  
while(!bStop) ]H:K$nmX  
{ ~$a%& ]\  
write_nPos(); ku^2K  
Utility.sleep(500); suj}A  
breakWhile = true; etW-gbr  
!x:w2  
Rx<[bohio  
for(int i=0;i<nStartPos.length;i++) 1?+)T%"  
{ 8/34{2048  
if(!fileSplitterFetch.bDownOver) {iq{<;)U?U  
{
S4O:?^28  
breakWhile = false; A&'HlI%J  
break; /=OSGIJzm  
} `~t$k7wm=  
} Q!%CU8!`&  
if(breakWhile) 7L:R&W6  
break; zGFW?|o<  
S4~;bsSx  
~w%Z Bp  
//count++; 28+Sz>SP  
//if(count>4) ]*;+ U6/?  
// siteStop(); Ll
&5#q  
} Tf[-8H<  
oB Bdk@  
z
T+yZA.L  
System.err.println("文件下载结束！"); cl7+DAE  
} Pq7tNM E  
catch(Exception e){e.printStackTrace ();} N<Q}4%
^c  
} uJp}9B60_  
J&:0ytG  
tT#Q`c
B  
//获得文件长度 kAk,:a;P  
public long getFileSize() #WpO9[b>  
{ E.% F/mM  
int nFileLength = -1; fW}H##b  
try{ |QgXSe7  
URL url = new URL(siteInfoBean.getSSiteURL()); RBg
kC+2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c!\y\r  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~O 6~',KD  
\M532_w  
}>XSp)"{l  
int responseCode=httpConnection.getResponseCode(); R+JI?/H  
if(responseCode>=400) ze\~-0ks+  
{ et ~gO!1:*  
processErrorCode(responseCode); }EIwkz
8  
return -2; //-2 represent access is error =
L wX+c  
} n0i&P
9@B1  
o%9>elOju  
jh0$:6 `C  
String sHeader; 0De M  
O.}gG6u5  
|uZ=S]V@  
for(int i=1;;i++) `U1%d7[vY  
{ aQ
mL=9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r;T/  
//Utility.log(in.readLine()); #f~a\}$I  
sHeader=httpConnection.getHeaderFieldKey(i); l{a&Zy)  
if(sHeader!=null) KE&}*Nf[  
{ g^4FzJ  
if(sHeader.equals("Content-Length")) _TXV{<E6  
{ _~(Xd@c(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Y)*lw  
break; 9c7}-Go  
} q5W'P>  
} S7q&|nI  
else {G0)mp,  
break; mfN@tMp  
} rWs5s!l,  
} KJ)&(Yx  
catch(IOException e){e.printStackTrace ();} N]<gHGj}  
catch(Exception e){e.printStackTrace ();} XfrnM^oty  
_dBU6U:V  
h*9o_  
Utility.log(nFileLength); S+y2eP G  
=5M>\vt]  
dJ^`9W  
return nFileLength; G0Eq}MyF  
} /a|NGh%  
7 f*_  
<"+C<[n.  
//保存下载信息（文件指针位置） RM+E  
private void write_nPos() KRZV9AJ  
{ U.F65KaKF  
try{ /nP=E  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6;pREM+  
output.writeInt(nStartPos.length); WLl9>v^1  
for(int i=0;i<nStartPos.length;i++) j1
kc&(  
{ w$ {  
// output.writeLong(nPos); B~#@fI
L  
output.writeLong(fileSplitterFetch.nStartPos); ~QcKW<bz  
output.writeLong(fileSplitterFetch.nEndPos); G]1pGA;  
} %nh'F6bNgv  
output.close(); R4(8]oUW  
} -*M:OF"Zh  
catch(IOException e){e.printStackTrace ();} P[K=']c  
catch(Exception e){e.printStackTrace ();} m^.
C(}  
} %p60pn[(  
jf/9]`Hf  
k#) .E X  
//读取保存的下载信息（文件指针位置） &zcjU+n  
private void read_nPos() wcf_5T  
{ ACYn87tq  
try{ ;alFK*K6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); FO=1P7  
int nCount = input.readInt(); m_ m@>}ud  
nStartPos = new long[nCount]; OP}p;(  
nEndPos = new long[nCount]; ,-Nk
-g  
for(int i=0;i<nStartPos.length;i++) <R>ZG"m{  
{ BD-=y  
nStartPos = input.readLong(); K:@=W1  
nEndPos = input.readLong(); I}IW!K  
} q)b?X ^  
input.close(); QZox3LM1&.  
} >NA7,Z2.  
catch(IOException e){e.printStackTrace ();} NF!1)  
catch(Exception e){e.printStackTrace ();} +:%FJCOT  
} K>6k@okO  
-(}1o9e\7  
tlgvBRH>  
private void processErrorCode(int nErrorCode) Y`?X Fy:  
{ [Mc5N  
System.err.println("Error Code : " + nErrorCode); ]!aa#?Fc  
} J6ShI
Pc  
A_~
5|  
MjC%6%HI  
//停止文件下载 "\r~,S{:  
public void siteStop() <SZO- -+lB  
{ XSjelA?  
bStop = true; CZRo{2!?U  
for(int i=0;i<nStartPos.length;i++) \Egc5{   
fileSplitterFetch.splitterStop(); (v:ek_  
ja- ~`  
b_Jq=Gk`  
} +|YZEC  
} HbfB[%  
//负责部分文件的抓取 a BH1J]_  
**FileSplitterFetch.java B!ibE<7,  
*/ g
+)\/n|  
package NetFox; yKEFne8^  
,D2_Z]  
hyfnIb@~}  
import java.io.*; PZRn6Tc  
import java.net.*; .{a2z*o  
*;E+9^:V  
{b0&qV   
public class FileSplitterFetch extends Thread {
'A!/pUML  
X6GkJ R  
$uK"@Mw  
String sURL; //File URL */y]!<\v!k  
long nStartPos; //File Snippet Start Position A'QGTT  
long nEndPos; //File Snippet End Position Wx)U<:^e  
int nThreadID; //Thread's ID fR%1FXpK&  
boolean bDownOver = false; //Downing is over qK vr*xlC  
boolean bStop = false; //Stop identical hUvuq,LH_  
FileAccessI fileAccessI = null; //File Access interface 3;S`
<  
0(/D|  
/NX7Vev  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yL x .#kx6  
{ vSC0D7BlG  
this.sURL = sURL; OrEuQ-,i@  
this.nStartPos = nStart; k5;Vl0Ho  
this.nEndPos = nEnd; q,+kPhHEgy  
nThreadID = id; t`YZ)
>Ws  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 aC~n:0v  
} *8.@aX3  
(2bZ]  
!aw#',r8m  
public void run() N^(lUba  
{ ~gWd63%8x  
while(nStartPos < nEndPos && !bStop) apD=>
O  
{ o?mXxL)  
h`h>H X  
k7|z$=zY  
try{ Gh[`q7B Q  
URL url = new URL(sURL); _OU.JrqC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^h6$>n5  
httpConnection.setRequestProperty("User-Agent","NetFox"); H4'DL'83  
String sProperty = "bytes="+nStartPos+"-"; ,' rL'Ys  
httpConnection.setRequestProperty("RANGE",sProperty); v;]I^Kq  
Utility.log(sProperty); k3>ur>aW  
$W {yK+N  
,mjfZ*N  
InputStream input = httpConnection.getInputStream(); 
gr`Ar;  
//logResponseHead(httpConnection); [}ZPg3Y  
o47   f  
^Z>B/aJq  
byte[] b = new byte[1024]; xPDA475Cw3  
int nRead; p=_XM
h`;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Vx6?@R  
{ fHe0
W  
nStartPos += fileAccessI.write(b,0,nRead); FL#g9U>  
//if(nThreadID == 1) (ND5CKCR^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r3H}*Wpf  
} ^/C$L8#  
1 73<x){  
Go\} A:|s  
Utility.log("Thread " + nThreadID + " is over!"); Z#F,y)YiO  
bDownOver = true; of'ZNQ/  
//nPos = fileAccessI.write (b,0,nRead); !q$&JZY  
} jxnQG A  
catch(Exception e){e.printStackTrace ();} En,)}yI  
} ~i }+P71  
} }xf='lE  
nRXSW&V"m  
kUg+I_j6*  
//打印回应的头信息 UGmuX:@y76  
public void logResponseHead(HttpURLConnection con) :qAc= IC%  
{ \7t5U7v8U  
for(int i=1;;i++) 833%H`jQc  
{ uojh%@.4  
String header=con.getHeaderFieldKey(i); ! nCjA\$  
if(header!=null) 7O+Ij9+{n  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); vdH+>l  
Utility.log(header+" : "+con.getHeaderField(header)); jKj=#O
 
else sArje(5Eo  
break; (lN;xT`=  
} p<HTJ0  
} NDRW  
XatA8(_,5  
Cgz&@@j,]  
public void splitterStop() Z\|u9DO  
{ h eE'S/  
bStop = true; WjY{rM,K  
}  vr{'FMc  
5>ADw3z'  
0Oc}rRH(C  
} 3'[Rvy{  
vQKn=  
*U;4t/(  
/* X`fhln9N  
**FileAccess.java 5@ bc(H  
*//文件访问(定位，写) [;?"R-V"z  
package NetFox; JFG",09]  
import java.io.*; qukjS#>+  
&0+x2e)7g  
6wb^*dD92  
public class FileAccessI implements Serializable{ b8N[."~:  
).NcLJw_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 W&+y(Z-t  
RandomAccessFile oSavedFile; "YG\  
long nPos; O->_/_  
(ve+,H6w\  
k-WHHoU>o  
public FileAccessI() throws IOException Qj 6gg  
{ cc|CC Zl  
this("",0); *.m{jgi1X  
} r"{Is?yKe  
6kt]`H`cfJ  
,4H;P/xsb  
public FileAccessI(String sName,long nPos) throws IOException i1qS ns  
{ J
o{zy  
oSavedFile = new RandomAccessFile(sName,"rw"); mb0n}I_AC  
this.nPos = nPos; Ky[bX  
oSavedFile.seek(nPos); kqVg2#<@M  
} 8^/+wa+G  
cT-K@dg  
3y
TQ  
public synchronized int write(byte[] b,int nStart,int nLen) T&
1-eq>l  
{ {q&@nm40  
int n = -1; @J-plJ4e  
try{ ug^om{e-  
oSavedFile.write(b,nStart,nLen); `OKo=e~,  
n = nLen; CN.6E<9'kK  
} e7@li<3>d  
catch(IOException e) %{R_^Y8t  
{ 5oz>1  
e.printStackTrace (); m_Mwg  
} <9ma(PFa  
=m`l%V[  
?VwK2w$&={  
return n; r_Lu~y|  
} S?*^>Y-e;  

("_Q  
!xkj30O(G  
} 'sj9[o@]  
sf Dg/ a  
&&;ex9  
/* P?^JPbfV  
**SiteInfoBean.java SK's!m:r=  
*/ ?E%+}P  
package NetFox; x.I][(}  
kr^0% A  
hzaU8kb  
public class SiteInfoBean { cX2$kIs;  
GGCqtA^@7d  
Js/N()X  
private String sSiteURL; //Site's URL %fHH{60  
private String sFilePath; //Saved File's Path 1|W
2s\  
private String sFileName; //Saved File's Name ('=Z}~  
private int nSplitter; //Count of Splited Downloading File X$/E>I  
j*XjY[  
>f>V5L%1  
public SiteInfoBean() /x$}D=(CZ  
{//nSplitter的缺省值为5 g{e/X~  
//default value of nSplitter is 5 21U&Ww  
this("","","",5); LyIKP$t  
} -:MmSeG7gO  
SGt5~Txj  
O47PkP8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jQ6Xr&}  
{ Tj=gRQ2v  
sSiteURL= sURL; UL&} s_  
sFilePath = sPath; > 84e`aGE  
sFileName = sName; 4bnt=5]  
this.nSplitter = nSpiltter; yKYl@&H/%  
@9aGz6k+  
h{I`7X  
} Z%#^xCz;w>  
YUCC*t  
DacN{r"3  
public String getSSiteURL() 1t.R+1[c  
{ ((qGh>*  
return sSiteURL; }"hW b(  
} ] @ufV  
> V8sm/M  
0 <
g{ V  
public void setSSiteURL(String value) )Bo]=ZTJ^  
{ gSb,s [p&+  
sSiteURL = value; d,UCH  
} NddO*`8+)  
e^zHw^js  
opXDm\  
public String getSFilePath() "e@n:N!  
{ 7{4w
2)  
return sFilePath; YGETMIT(  
} H37QgApB  
e gI&epN  
19p8B&  
public void setSFilePath(String value) uxb:^d?D!  
{ :5jexz."M  
sFilePath = value; BX*69  
} P].eAAXnP  
`kFiH*5%z  
r_^)1w  
public String getSFileName() Tpb"uBiXoo  
{ FI$XSG  
return sFileName; grspt}  
} t{zBC?cR  
*jE;9^  
h48YDWwy  
public void setSFileName(String value) h,t:]  
{ P3!Atnv2  
sFileName = value; z6I%wh  
} d*2u}1Jo8  
0\Y1}C  
DHv2&zH  
public int getNSplitter() ^^U%cuKg  
{ !>3LGu,  
return nSplitter; ;}K62LSR  
} >'b=YlUL  
q_sEw~~@!  
%m`zWg-  
public void setNSplitter(int nCount) lI6W$V\,  
{ &n>
7Ir  
nSplitter = nCount; L=]p_2+  
} xzr<k S
p  
} [pL*@9Sa&  
t"|DWC*  
-uj3'g(;w  
/* ^s-25 6iI  
**Utility.java JhP\u3 QE  
*/ h&`y$Jj  
package NetFox; _~&9*D$ {>  
DZk1Z
Lz  
f@d9Hqr+l;  
public class Utility { m(_9<bc>  
Us=eq "eu  
`eR 7H>I  
public Utility() Om9jtWk  
{ _{)9b24(  
s$ z2 c  
T<yb#ak  
} KmmQ,e%  
4x=(Zw_X  
//线程睡眠 ~KPv7WfG  
public static void sleep(int nSecond) 4-^[%&>}  
{ 0[Eb .2I  
try{ ykmv'a$-4  
Thread.sleep(nSecond); v@n_F  
} E oe}l   
catch(Exception e) t,H
Fz6   
{ ! %Ny0JkO  
e.printStackTrace (); ?aWx(dVQ  
} :o8MUXH$  
} hqDqt"dKz  
9:8|)a(1  
//日志 EI1? GB)b  
public static void log(String sMsg) o\!qcoE2W  
{ fd1C{^c  
System.err.println(sMsg); y}"7e)|t%  
} /pykW_`/-  
y vI<4F  
"@yyXS r  
public static void log(int sMsg) X{Zm9T  
{ J'Sm
0  
System.err.println(sMsg); :mZYS4L~  
} `]<`$71w  
} Fe!9y2Mg  
fzPZ|  
;dZMa]X0  
/* JvL{| KtyU  
**TestMethod.java Cy@ cLdV  
*/ L'E^c,-x~  
package NetFox; fYX<d%?7  
eV2mMSY  
tJU-<{8  
public class TestMethod { .zkP~xQ~  
Md&WJ };L  
eB]R3j{  
public TestMethod()  rLv;Y  
{ ///xx/weblogic60b2_win.exe Ia4)uV8  
try{ #fDs[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *C2R`gpBI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {HrZ4xQnpV  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d5!!U
t  
fileFetch.start(); J^ G  
} Apfnx7Fv  
catch(Exception e){e.printStackTrace ();} ;Gd~YGW^#  
MbA\pG
'T  
4 b,N8  
} 2?DRLF]  
{x@|VuL=  
xDjV`E]  
public static void main(String[] args) T?wzwGp-[  
{ |"Z{I3Umg  
new TestMethod(); <+tD z(  
} Adx`8}N8  
} $/Ov2z  
点击下载更多相关资料