http断点续传简单实现（java)

/* T*-*U/  
**SiteFileFetch.java 3`IDm5  
*/ 3,3{wGvHHW  
package NetFox; /=,^fCCN  
import java.io.*; roj/GZAy"  
import java.net.*; <MA!?7Z|  
(RWZ[-;)  
V*U"OJ%  
public class SiteFileFetch extends Thread { DtXXfp@;  
\C/`?"4w  
5#$E4k:YV  
SiteInfoBean siteInfoBean = null; //文件信息Bean S;i^ucAF  
long[] nStartPos; //开始位置 A<y3Tc?Q  
long[] nEndPos; //结束位置 J U}XSb  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 W4|1wd}.t  
long nFileLength; //文件长度 WI[6l6  
boolean bFirst = true; //是否第一次取文件 92+({ fgW  
boolean bStop = false; //停止标志 iDp]lu  
File tmpFile; //文件下载的临时信息 zdU<]ge  
DataOutputStream output; //输出到文件的输出流 H6bomp"  
V1x
pJ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \ $X3n\  
public SiteFileFetch(SiteInfoBean bean) throws IOException `:i|y  
{ K)l{3\9l|  
siteInfoBean = bean; "*kWM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Vy16Co  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qECc[)B  
if(tmpFile.exists ()) onG,N1`+  
{ 1g2%f9G  
bFirst = false; {
~
b]6}O  
read_nPos(); zRsT6u  
} ]$y"|xqR  
else = fuF]yL%  
{ [q9TT
J@2  
nStartPos = new long[bean.getNSplitter()]; H8Pil H  
nEndPos = new long[bean.getNSplitter()]; W{1=O)w  
} JEU?@J71O  
RTHdL  
s:jr/ j!  
Itj|0PGd  
} xqmJPbA  
x%vt$dy*8  
O 4l[4,`  
public void run() yr[iAi"  
{ o Ep\po1  
//获得文件长度 $T1 D ?X  
//分割文件 lOI(+74  
//实例FileSplitterFetch xyBe*,u  
//启动FileSplitterFetch线程 xg. d
)n  
//等待子线程返回 2EQ:mjxk  
try{ L a0H  
if(bFirst) H
Tf7
r-  
{ Ij@YOt  
nFileLength = getFileSize(); +%UXI$v  
if(nFileLength == -1) /D 2v1  
{ X<,sc;"b`k  
System.err.println("File Length is not known!"); D GOc!  
} ]Ny.  gu  
else if(nFileLength == -2) Zo-s_6uC  
{ N$:[`,  
System.err.println("File is not access!"); ]c[80F-  
} KB*[b  
else Kdik7jL/J  
{ @~QW~{y  
for(int i=0;i<nStartPos.length;i++) p`33`25  
{ ~?[%uGI0h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l'B`f)  
} QmT]~
4PqS  
for(int i=0;i<nEndPos.length-1;i++) 5<,}^4wWZ  
{ :E@"4O?<Y)  
nEndPos = nStartPos[i+1]; ?G0=\U< o,  
} 1UyI.U]  
nEndPos[nEndPos.length-1] = nFileLength; A;Xn#t ,(K  
} Ur?a%]  
} `Qaw]&O  
Y;xVB" (  
$N+a4  
//启动子线程 Le|Ho^h,Y
 
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vxk1RL*Xu  
for(int i=0;i<nStartPos.length;i++) WP2|0ib  
{ Co[  r
hs  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J@p[v3W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xh_6@}D2J  
nStartPos,nEndPos,i); ]{.rx),  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {p yo  
fileSplitterFetch.start(); hgfCM  
} ?9 :{p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D!TS/J1S;u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6$9n_AS  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", z"=#<C  
nEndPos = " + nFileLength); >9uDY+70I3  
// fileSplitterFetch[nPos.length-1].start(); {-7];e  
bn~=d@'  
4F)z-<-b  
//等待子线程结束 BqCBH!^x  
//int count = 0; aOyAP-m,  
//是否结束while循环 zw7=:<z=  
boolean breakWhile = false; q 1Rk'
k4+  
%fJ*Ql4M  
k .KN9=o  
while(!bStop) j
xZR%D  
{ )0yY|E\  
write_nPos(); 7t0\}e  
Utility.sleep(500); 2o
Gl"3/p  
breakWhile = true; f,)[f M4  
 [^8*9?i4  
0 #VH=pga  
for(int i=0;i<nStartPos.length;i++) x6.an_W6  
{ b_W0tiyv%  
if(!fileSplitterFetch.bDownOver) h<$Vry}  
{ :G9.}
VrU  
breakWhile = false; )o SFHf  
break; w`CGDF\Oo  
} t(\d;ybyx  
} ]9l=geZd%;  
if(breakWhile) 5A>W;Q\4  
break; PHyS^J`  
u/hFf3  
=xS(Er`r  
//count++; f]h99T  
//if(count>4) -
9UQs.Nv  
// siteStop(); yLW iY~Fd  
} ;E,%\<  
6*A S4l  
sG%Q?&-
 
System.err.println("文件下载结束！"); Qx>S>f  
} V/.Y]dN5  
catch(Exception e){e.printStackTrace ();} DQ?'f@I&*  
} JY"<b6C^  
 G;Q)A$-  
b*no.eB  
//获得文件长度 &\F`M|c  
public long getFileSize() W=M]1hy  
{ B+ud-M0  
int nFileLength = -1; 1,p7Sl^h  
try{ 
<*i
'  
URL url = new URL(siteInfoBean.getSSiteURL()); ?}D@{%O3T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CSN]k)\N(  
httpConnection.setRequestProperty("User-Agent","NetFox"); /VgA}[%y  
)|~pocXt<  
Q0Y0Zt,h  
int responseCode=httpConnection.getResponseCode(); iN %kF'&9  
if(responseCode>=400) +?),BRCce  
{ C:"Al-  
processErrorCode(responseCode); lM3UjR|@  
return -2; //-2 represent access is error uCB7(<  
} 9KN75<n  
c`yLn%Of%  
T$U,rOB"  
String sHeader; -fI-d1@  
h\Ck""&  
6D_3Hwrs  
for(int i=1;;i++) T\eOrWt/  
{ t
7pe)i,)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h.gj4/g  
//Utility.log(in.readLine()); ykrb/j|rK  
sHeader=httpConnection.getHeaderFieldKey(i); byR|L:L  
if(sHeader!=null) EtjN :p|$  
{ ?B.>VnYZ/a  
if(sHeader.equals("Content-Length")) NRe{0U}nO  
{ p&/}0eL y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ak 94"<p  
break; HP}d`C5<R  
} hg_@Ui@[z  
} sPuNwVX>}I  
else "a %5on  
break; ?B3   
} w#_/CUL  
} @iWql*K;m  
catch(IOException e){e.printStackTrace ();} 4,"%  
catch(Exception e){e.printStackTrace ();} H3"90^|,@  
G9J+D?'hH  
&i179Qg!  
Utility.log(nFileLength); ys`"-o[*  
0\*[7!`s  
M}2a/}4
 
return nFileLength; [}Vne;V  
} 3@P 2]Q~D  
[+<lm 5t  
Loo48  
//保存下载信息（文件指针位置） q^NI  
private void write_nPos() <3i2(k  
{ 5xKo(XNp  
try{ %2>ya>/M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YTP6m9hA+  
output.writeInt(nStartPos.length); V`Ve__5;  
for(int i=0;i<nStartPos.length;i++) QS.t_5<U  
{ d;1%Ei3K  
// output.writeLong(nPos); l>p S23  
output.writeLong(fileSplitterFetch.nStartPos); #Duz|F+%  
output.writeLong(fileSplitterFetch.nEndPos); =w&JDj  
} ,ND}T#yTR  
output.close(); (ns>z7  
} w;f$oT  
catch(IOException e){e.printStackTrace ();} v53qpqc  
catch(Exception e){e.printStackTrace ();} GR6BpV7  
} =To}yJ#  
gYb}<[O!  
it?l! ~  
//读取保存的下载信息（文件指针位置） G1K72M}CW  
private void read_nPos() Reci:T(_  
{ 2rK%fV53b  
try{ ^0"W/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rm}OVL  
int nCount = input.readInt();
]7
W!  
nStartPos = new long[nCount]; ,
H$1iJ?  
nEndPos = new long[nCount]; 'Bul_D4B  
for(int i=0;i<nStartPos.length;i++) Tp7*
T
8  
{ *2wFLh  
nStartPos = input.readLong(); F/1B>2$`  
nEndPos = input.readLong(); )q#1C]7m*  
} L{XNOf3  
input.close(); dG5p`N%  
} !I3_KuJ5  
catch(IOException e){e.printStackTrace ();} 'L$%)`;e  
catch(Exception e){e.printStackTrace ();} -1^dOG6*  
} !8'mIXZ$  
)<Cf,R  
Qv~KGd9  
private void processErrorCode(int nErrorCode) _G9vsi  
{ f]N.$,:$  
System.err.println("Error Code : " + nErrorCode); |"7F`M96I  
} VG,O+I'^z  
V)HX+D>  
sw:o3cC]  
//停止文件下载 o{C7V*  
public void siteStop() 8HL$y-F  
{ `R\aNgCS}  
bStop = true; W ='c+3O6  
for(int i=0;i<nStartPos.length;i++) V(/ @$&  
fileSplitterFetch.splitterStop(); fU?P__zU4  
ZjCT * qx  
'!$g<= @  
} &356   
} f8Z[prfP  
//负责部分文件的抓取 tXl
o27J  
**FileSplitterFetch.java d#Hl3]wT  
*/ 8 K7.; t1  
package NetFox; *OoM[wEY  
4<P=wK=a8X  
}@+3QHwYU  
import java.io.*; dCbRlW  
import java.net.*; ape\zZCV  
C2$_Ad=s  
j=&]=0F  
public class FileSplitterFetch extends Thread { "'#18&N  
g>L4N.ZH_v  
6a_MA*XK  
String sURL; //File URL )9oF?l^q  
long nStartPos; //File Snippet Start Position j<BW/  
long nEndPos; //File Snippet End Position ]g/:lS4  
int nThreadID; //Thread's ID J
f#Ika&px  
boolean bDownOver = false; //Downing is over FabDK :  
boolean bStop = false; //Stop identical -'q#u C  
FileAccessI fileAccessI = null; //File Access interface Z4&,KrV  
q?&Ap*  
E.ugr])  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #o>~@.S#:0  
{ .dbZ;`s  
this.sURL = sURL; ~2HlAU))<&  
this.nStartPos = nStart; ][gr(-68  
this.nEndPos = nEnd; ()Tl\  
nThreadID = id; n8FmIoZ&`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 HITw{RPrW  
} -VC kk  
*VP-fyJp  
E4CyW  
public void run() Ht{Q=w/9  
{ C>}@"eK  
while(nStartPos < nEndPos && !bStop) @k|V4  
{ q
=,  
e$vvmbK.  
5 R*  
try{ B.Szp_$  
URL url = new URL(sURL); 3QD+&9{D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qcmf*Yl:v  
httpConnection.setRequestProperty("User-Agent","NetFox"); [. rULQ
l  
String sProperty = "bytes="+nStartPos+"-"; iNlY\67sW  
httpConnection.setRequestProperty("RANGE",sProperty); 2#i*'.  
Utility.log(sProperty); j\LJ{?;jC  
EC:u;2f!  
\dx$G?R
 
InputStream input = httpConnection.getInputStream(); jmE\+yz  
//logResponseHead(httpConnection); GR%h3HO2&  
XCo3pB Wq~  
:l;SG=scx  
byte[] b = new byte[1024]; w3<%wN>tE  
int nRead; 0gIJ&h6*f  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q>%{Dn\?  
{ r;7&U<j~Z  
nStartPos += fileAccessI.write(b,0,nRead); ]ChGi[B~9  
//if(nThreadID == 1) +46m~" ]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G/)]aGr  
} 3*v&6/K  
0etJ, _">  
r@30y/C  
Utility.log("Thread " + nThreadID + " is over!"); :TZ</3Sw  
bDownOver = true; xY=%+o.?*  
//nPos = fileAccessI.write (b,0,nRead); Fr|Ts>Kx  
} f|r+qe  
catch(Exception e){e.printStackTrace ();} {F'~1qf  
} O:J;zv\  
} o3ZqPk]al  
6?(Z f  
!RPPwvNk4  
//打印回应的头信息 ;+Sc Vz  
public void logResponseHead(HttpURLConnection con) 37U2Tb!y'  
{ vNn$dc  
for(int i=1;;i++) U#mrbW  
{ T1_
qAz+  
String header=con.getHeaderFieldKey(i); *?`<
Ea  
if(header!=null) uO{'eT~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); c`M ,KXott  
Utility.log(header+" : "+con.getHeaderField(header)); 3;F+
.{Icc  
else ?3t]9z  
break; 5;:964Et  
} G,-x+e"  
} 66Tx>c"H  
cg|C S?  
Y2oN.{IH  
public void splitterStop() LvcGh  
{ >>I~v)a>w  
bStop = true; \)/dFo\l  
} BK[ YX)  
9C"d7--  
';J><z{>  
} {sR|W:fS$  
79y'PFSms  
n
B.u5  
/* B4/\RC2  
**FileAccess.java Z]\IQDC  
*//文件访问(定位，写) )2
Dm{T  
package NetFox; })TXX7[h  
import java.io.*; s6HfN'  
>VE!3'/'  
rE5q BEh  
public class FileAccessI implements Serializable{ 6d#:v"^,  
[}1+=Ub  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,enU`}9V*  
RandomAccessFile oSavedFile; =AVr<kP  
long nPos; XT<{J8 0z  
t)n}S;iD  
Rct=vDU  
public FileAccessI() throws IOException G8hq;W4@]/  
{ c)Ep<W<r1  
this("",0); .KX LWH  
} ;z3w#fNMv  
tEC`
->|  
Xt%>
XP  
public FileAccessI(String sName,long nPos) throws IOException WVkJ=r0Ny  
{ ;qwNM~  
oSavedFile = new RandomAccessFile(sName,"rw"); # ZcFxB6)  
this.nPos = nPos; AriW&E  
oSavedFile.seek(nPos); >SSRwYIN  
} cfrvx^,2&  
n1;y"`gHk  
&LM ^,xx}  
public synchronized int write(byte[] b,int nStart,int nLen) r_EuLFMA  
{ v9S1<|j
N  
int n = -1; fo$Ac  
try{ bPhbd  
oSavedFile.write(b,nStart,nLen); fd&=\~1_$  
n = nLen; ?T\_"G  
} xZ.c@u6:  
catch(IOException e) t^KoqJ  
{ G&f~A;'7k  
e.printStackTrace (); Xb/^n.>  
} pU)g93  
qR>"r"Fq  
D8r=Vf  
return n; ??g`c=R!V  
} hrZ=8SrW  
se,0Rvkt  
8Z1pQx-P2C  
} Kulh:d:w  
HyX:4f|]'  
rZSX fgfr  
/* _6/q.  
**SiteInfoBean.java Lr;PESV  
*/ lMW4SRk1C  
package NetFox; 25-5X3(>j=  
|v?*}6:a  
pQ/ bIuq  
public class SiteInfoBean { #nS[]UbwZ  
_5l3e7YN  
xZpGSlA  
private String sSiteURL; //Site's URL %^VQw!  
private String sFilePath; //Saved File's Path { kF"<W  
private String sFileName; //Saved File's Name szG0?e  
private int nSplitter; //Count of Splited Downloading File *LZ^0c:r  
vi-mn)L6#  
%I>-_el  
public SiteInfoBean() Or9`E(  
{//nSplitter的缺省值为5 ;xMieqz  
//default value of nSplitter is 5 SWZA`JVK  
this("","","",5); -0R;C`(!  
} r@9qjva  
yccF#zU  
\Tii S  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4Bc<  
{ %J%ZoptY:  
sSiteURL= sURL; 8/16<yZ  
sFilePath = sPath; &:MfLDJ  
sFileName = sName; $4Ko  
this.nSplitter = nSpiltter; I'$}n$UvZ  
Mq[|w2.  
`E4OgO  
} wn-{Vkpm  
$,v[<T`  
!(L\X'jH  
public String getSSiteURL() ulzQ[?OMl  
{ (RtjD`e}  
return sSiteURL; D3i`ehh  
} 5lp};  
IQ3]fLb  
^>H+#@R  
public void setSSiteURL(String value) $k=5nJ  
{ SF#Rc>v  
sSiteURL = value; K,o@~fj  
} +CF"Bm8@  
-'jPue2\  
WI+ 5x  
public String getSFilePath() .o!z:[IPY  
{ <Z6tRf;B  
return sFilePath; Pu-/*Fx  
} Er]lObfQo  
{?zbrgQ<Z  
?*ni5\y5o  
public void setSFilePath(String value) 'dFhZ08u}  
{ P O{1u%P  
sFilePath = value; 5/{";k)L+  
} 3jG #<4;J  
mhXSbo9w-  
Jfkdiyy"  
public String getSFileName() n$S`NNO{]  
{ *gxo!F}  
return sFileName; pPX~pPIj2  
} QoVRZ$!p  
FYtf<C+  
EDkxRfY2/  
public void setSFileName(String value) z%
pD3J?>  
{ 9^5D28y  
sFileName = value; 7KzMa%=  
} `AO<r  
/j0zb&  
zJJ6"9sl  
public int getNSplitter() :y!%GJW  
{ ]|y]?7  
return nSplitter; tgX},OU^  
} H^e0fm  
kQY+D1  
E*F)jP,yo  
public void setNSplitter(int nCount) ^ew<|J2,B  
{ n!*uv~%$  
nSplitter = nCount; Q4&|^RLLG  
} d'yA"b]  
} X%>Sio  
~il{6Z+#n  
1p[Z`m*9  
/* ?(!<m'jEy  
**Utility.java 5r$X  
*/ +z2+z  
package NetFox; ;Q0WCm\5  
q:9#Vcw  
^ld?v  
public class Utility { VZJ[h{ 6  
^S'#)H-8C3  
Rt{`v<  
public Utility() 
W?B(Jsv  
{ BIr24N  
K[XFJ9  
=`l).GnN2`  
} {_]'EK/w  
5"]t{-PD  
//线程睡眠 jr9/  
public static void sleep(int nSecond) y+PiH  
{ -a}d @&  
try{ dK45&JHoW^  
Thread.sleep(nSecond); HcrI3v|6  
} 8] BOq:
 
catch(Exception e) 1;4] HNI  
{ #''q :^EQ  
e.printStackTrace (); +[DL]e]@U  
} bS9<LQ*  
} 0K&\5xXM  
Viu+#J;l  
//日志 nv9kl Q@  
public static void log(String sMsg) J"x M[c2  
{ "1U:qr2-H  
System.err.println(sMsg); e[lRY>Pe5  
} {Y%X  
dUTF0
U  
~x>?1K  
public static void log(int sMsg) e(^\0=u<  
{ a09]5>*  
System.err.println(sMsg); dtdz!'q)Y  
} c==` r C  
} _l`s}yC  
5 E%dF9q  
z'G~b[kG4n  
/* +N9(o+UrU  
**TestMethod.java r`Qzn" H  
*/ O!b >  
package NetFox; Y2DR oQ  
I.<>6ISI@  
;btH[a iV  
public class TestMethod { 6[h3pb/m  
.Jt&6N  
0aMw  
public TestMethod() '~^3 =[Z  
{ ///xx/weblogic60b2_win.exe CaZ{UGokL  
try{ fR>(b?C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kQR
kby  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %}U-g"I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m,e@bJ-  
fileFetch.start(); QES[/i +  
} X5'QYZ6kv  
catch(Exception e){e.printStackTrace ();} G_wzUk=L  
])=k";76  
"RG
.2
7  
} ^AWM/aY  
v'C`;I  
(ia
(y(=C  
public static void main(String[] args)
mCtuR*z_  
{ ]_S&8F}|  
new TestMethod(); I9ga8mG4-'  
} cS98%@DR  
} G[YbgG=9Y  
点击下载更多相关资料