http断点续传简单实现（java)

/* =zwn3L8fL  
**SiteFileFetch.java 3ZL<6`YF  
*/
AKUmh  
package NetFox; m+dJ3  
import java.io.*; 9.l*#A^  
import java.net.*; [Pz['q L3t  
+)e+$ l  
|il P>b  
public class SiteFileFetch extends Thread { Zopi;O J  
#J*hZ(Pq  
bb`8YF+?'  
SiteInfoBean siteInfoBean = null; //文件信息Bean a~Y`N73/c  
long[] nStartPos; //开始位置 <3[0A;W=1  
long[] nEndPos; //结束位置 lemUUl(^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 t$ 3/ZTx  
long nFileLength; //文件长度 GNI:k{H@"?  
boolean bFirst = true; //是否第一次取文件 O
u2p^:C(  
boolean bStop = false; //停止标志 6fw2;$x"  
File tmpFile; //文件下载的临时信息 F+m;y  
DataOutputStream output; //输出到文件的输出流 -h,?_d>  
Y/,Cy0!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） N9BfjT}  
public SiteFileFetch(SiteInfoBean bean) throws IOException DYW&6+%,hO  
{ ]R]%c*tA  
siteInfoBean = bean; L-Pq/x2r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); t'bhA20Z\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~>>^7oq  
if(tmpFile.exists ()) Pbl#ieZM  
{ )&.Zxo;q=  
bFirst = false; ;a~ e  
read_nPos(); }6 MoC0  
} wp>L}!  
else \~I>@SG2W+  
{ G57c 8}\4  
nStartPos = new long[bean.getNSplitter()]; h~u|v[@{J  
nEndPos = new long[bean.getNSplitter()]; d&t,^Hj  
} Fz@9
@  

$3^Cp_p6  
ix_&<?8  
~qezr\$2  
} fnJt8Y4  
gH|:=vfYUR  
}o@Dsx5  
public void run() &[y+WrGG  
{ _.^`DP>  
//获得文件长度 fsUZG6  
//分割文件 T8>aU  
//实例FileSplitterFetch rE9Nt9}  
//启动FileSplitterFetch线程 ~r?VXO p"  
//等待子线程返回 }5lC8{wZ  
try{ p?'&P!  
if(bFirst) I@:"Qee  
{ -$cO0RSY  
nFileLength = getFileSize(); b VcA#7 uA  
if(nFileLength == -1) ~Nn}FNe  
{ O#x=iZI  
System.err.println("File Length is not known!"); OzUo}QN  
} D7v_<  
else if(nFileLength == -2) ^D A<=C-[!  
{ s-JS[  
System.err.println("File is not access!"); lHc9D  
} /G= ?E]^  
else !p{
CsR8c  
{ 28LYGrB  
for(int i=0;i<nStartPos.length;i++) 1SSS0&  
{ j. mla  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); EM,=R  
} y=SVS3D  
for(int i=0;i<nEndPos.length-1;i++) 7(C:ty9  
{ #X qnH  
nEndPos = nStartPos[i+1]; WlmkM?@  
} my%MXTm2  
nEndPos[nEndPos.length-1] = nFileLength; p'\zL:3  
} _[$,WuG1  
} \"6?*L|]  
)_SpY\J  
k[{ ~eN:  
//启动子线程 ~
;ObT=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lwm 9gka  
for(int i=0;i<nStartPos.length;i++) Y |9  
{ %`}nP3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @IV,sze  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), qpV"ii  
nStartPos,nEndPos,i); LyRW\\z2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I*H($ a  
fileSplitterFetch.start(); QVo>Uit   
} 1\-r5e; BE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x%T.0@
!8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8~ u/gM  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q2<v: *L  
nEndPos = " + nFileLength); %#C9E kr  
// fileSplitterFetch[nPos.length-1].start(); ry0YS\W  
8T8
8  
-lm)xpp1  
//等待子线程结束 ) (0=w4  
//int count = 0; DqHJ *x4  
//是否结束while循环 aATNeAR  
boolean breakWhile = false; C!)ZRuRv  
OxN[w|2\4  
a] 7nK+N  
while(!bStop) 0G`@^`  
{ /h9v'Y}c  
write_nPos(); @W-0ybv  
Utility.sleep(500); C%H?vrR  
breakWhile = true; afE)yu`  
$N\k*=  
8&yI1XM|  
for(int i=0;i<nStartPos.length;i++) UT0}Ce>e  
{ 7QRkXs  
if(!fileSplitterFetch.bDownOver) \&[(PNl  
{ wU|jw(  
breakWhile = false; ic}mru  
break; L}rYh`bUP[  
} p4D.nB8  
} JT6}m  
if(breakWhile) RoNE7|gF:  
break; 6B+?X5-6DH  
D~n-;T  
d .%2QkL  
//count++; Yz#E0aTTA  
//if(count>4) _ Y7Um  
// siteStop(); g)7@EU2  
} g{CU1c)B  
k/1S7X[  
wV-9T*QrM  
System.err.println("文件下载结束！"); <!F".9c@A  
} 8*Ty`G&v  
catch(Exception e){e.printStackTrace ();} oxL)Jx\c9A  
} [}yPy))A  
}46Zfg\T6n  
}{)Rnb@ >  
//获得文件长度 nDyA][  
public long getFileSize() hbEqb{#}@  
{ #4<=Ira5  
int nFileLength = -1; !*S,S{T8  
try{  aW9\h_$  
URL url = new URL(siteInfoBean.getSSiteURL()); xjD."q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X8):R
- J  
httpConnection.setRequestProperty("User-Agent","NetFox"); kPoz&e_@  
I51I(QF=  
*7b?.{  
int responseCode=httpConnection.getResponseCode(); nw(R=C  
if(responseCode>=400) uU%Z%O  
{ QseV\;z  
processErrorCode(responseCode); W8F@nY  
return -2; //-2 represent access is error sR/y|  
} 'x5p ?m  
*W;;L_V"   
sf/m@425  
String sHeader; TbLU[(m-n  
q3C  
4U~'Oa@p  
for(int i=1;;i++) m_.9PZ  
{ L/In~'*-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); En)Ptz#0  
//Utility.log(in.readLine()); 0!oqP1  
sHeader=httpConnection.getHeaderFieldKey(i); ,4Q8r:_ u  
if(sHeader!=null) 2|ej~}Y  
{ U({
N'y=  
if(sHeader.equals("Content-Length")) X}Om)WCr  
{ n.t5:SW  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;M~9Yr=1  
break; a,(nf1@5  
} TO.STK`  
} #%w+PL:*O  
else maeQ'Sv_&  
break; \iaZV.#f  
}  A@9\Qd  
} <v/aquLN  
catch(IOException e){e.printStackTrace ();} :,fT^izew  
catch(Exception e){e.printStackTrace ();} Zu2`IzrG#  
w
E"lk  
MV2$
0  
Utility.log(nFileLength); \Zh&[D!2  
KDP"z  
iJj!-a:z.  
return nFileLength; R!yh0y}Z  
} )_\;l%&  
W?"l6s  
Pm%5c\ef  
//保存下载信息（文件指针位置） P(DEf(  
private void write_nPos() ![$`Ivro`  
{ [+QyKyhTO  
try{ `wZ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'HJ+)[0X*  
output.writeInt(nStartPos.length); v 2p  
for(int i=0;i<nStartPos.length;i++) p(nO~I2E  
{ TspX7<6r  
// output.writeLong(nPos); Na@;F{  
output.writeLong(fileSplitterFetch.nStartPos); \o=9WKc  
output.writeLong(fileSplitterFetch.nEndPos); 5gV,^[E-z  
} DB
G0)=SHy  
output.close(); LT>_Y`5>  
} hW'b'x<  
catch(IOException e){e.printStackTrace ();}  v\CBw"  
catch(Exception e){e.printStackTrace ();} %hN(79:g  
} o.w/?  
t- TUP>_  
lJN#_V0qW  
//读取保存的下载信息（文件指针位置） Pksr9"Ah  
private void read_nPos() U;IGV~oT  
{ +nHr+7}  
try{ YtKT3u:x  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Nsq=1) <  
int nCount = input.readInt(); w=<E)  
nStartPos = new long[nCount]; >2#<tH0  
nEndPos = new long[nCount]; Z,SV9 ~M  
for(int i=0;i<nStartPos.length;i++) F_g(}wE# q  
{ )">#bu$  
nStartPos = input.readLong(); yz!L:1DG  
nEndPos = input.readLong(); 2wnk~URj  
} YFPse.2$a  
input.close(); pdER#7Tq  
} 65JG#^)KaX  
catch(IOException e){e.printStackTrace ();} *0Z6H-Do,  
catch(Exception e){e.printStackTrace ();} 3 !8#wn  
} f0Q! lMv  
AZE%fOG<i  
)Ute
 
private void processErrorCode(int nErrorCode) >
~Gy+-  
{ ;?@Rq"*  
System.err.println("Error Code : " + nErrorCode); 8(l0\R,%+z  
} !/tV}.*  

g!' x5#]n  
YgjW%q   
//停止文件下载 |bSAn*6b  
public void siteStop() 0TA8#c  
{ ky]^N)  
bStop = true; ,/GFD[SQ  
for(int i=0;i<nStartPos.length;i++) tmoCy0qWz  
fileSplitterFetch.splitterStop(); b;d7mh4  
7Hv6>z#m  
2bLc57j{`9  
} `7y3C\zyQ  
} re/u3\S  
//负责部分文件的抓取 <9"@<[[,  
**FileSplitterFetch.java t(V2  
*/ %'h:G Bkd  
package NetFox; H.]V-|U  
T^vo9~N
*  
E;4B!"Q8  
import java.io.*; {d'B._#i  
import java.net.*; ?lgE9I]  
=WI3#<vDG  
D</?|;J#/  
public class FileSplitterFetch extends Thread { H7P}=YW".  
UJDI[`2  
@ U"Ib  
String sURL; //File URL Z:,\FB_U  
long nStartPos; //File Snippet Start Position \Gk}Fer  
long nEndPos; //File Snippet End Position U&:-Vf~&  
int nThreadID; //Thread's ID ME]7e^  
boolean bDownOver = false; //Downing is over ;`c:Law4  
boolean bStop = false; //Stop identical :|S[i('  
FileAccessI fileAccessI = null; //File Access interface E
$4H;SN \  
B8T5?bl  
w5s&Ws  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException w5)KWeGa  
{ L\"wz scn  
this.sURL = sURL; zVtTv-DU  
this.nStartPos = nStart; '_Pb\ jK  
this.nEndPos = nEnd; e 2NF.  
nThreadID = id; J Q*~le*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0vDvp`ie#4  
} #Dgu

V  
e@vZg8Ie  
R+He6c!?9  
public void run()  PBW_9&d  
{ u81F^72U  
while(nStartPos < nEndPos && !bStop) {yT<22Fl  
{ 8KigGhY'ms  
c[X6!_  
G.iQ\'1_h  
try{ DwFvM0O6\  
URL url = new URL(sURL); )>b1%x} =  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Sh-B!  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z ]ZUK  
String sProperty = "bytes="+nStartPos+"-"; ^-s7>F`jx  
httpConnection.setRequestProperty("RANGE",sProperty); AVU'rsXA  
Utility.log(sProperty); f>mEX='w  
;sf'"UnL  
5syzh S  
InputStream input = httpConnection.getInputStream(); ASMItT  
//logResponseHead(httpConnection); w""u]b%:r  
PIFZ '6gn  
R6>*n!*D@  
byte[] b = new byte[1024]; &1=,?s]&  
int nRead; v6aMYmenBH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) X=6L-^o)  
{ hHcevSr  
nStartPos += fileAccessI.write(b,0,nRead); .3Smqwm=Y  
//if(nThreadID == 1)
Vu~fF@ |  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C'l\4ij)7  
} 2fc+PE  
n]5Pfg|a  
<b\.d^=B  
Utility.log("Thread " + nThreadID + " is over!"); GpO@1 C/  
bDownOver = true; !f/^1k}SR  
//nPos = fileAccessI.write (b,0,nRead); L:lnm9<  
} m|+zMf&  
catch(Exception e){e.printStackTrace ();} b+ZaZ\-y |  
} d3T7$'l$  
} 9S'\&mRl  
#&S<{75A  
T}XJFV  
//打印回应的头信息 6OPNP0@r  
public void logResponseHead(HttpURLConnection con) yfFe%8w_vw  
{ .1J`>T?=Q  
for(int i=1;;i++) [tt_>O  
{ ?W?n l:F  
String header=con.getHeaderFieldKey(i); >B;S;_5=  
if(header!=null) q4"^G:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); aG@GJ@w  
Utility.log(header+" : "+con.getHeaderField(header)); >/@Q7V99{  
else B1i'Mzm-4  
break; A"+t[0$.  
} 436SIh  
} #vBSg  
R5uz<  
>i61+uzEd+  
public void splitterStop() {EU]\Mp0j  
{ ;yZY2)L  
bStop = true; Pff-eT+~m  
} .&^M Z8  
.fhfO @  
+`m0i1uI3  
} u |$GOSD  
!a'{gw  
MD>E0p)  
/* waV4~BdL  
**FileAccess.java K~5(j{Kb8  
*//文件访问(定位，写) ,0>_(5  
package NetFox; #]}G{ P  
import java.io.*; L`^v"W()  
\jkDRR[  
c1f`?i}.  
public class FileAccessI implements Serializable{ 2@ZuH^qhk  
CFY4PuI"!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 W$" >\A0%  
RandomAccessFile oSavedFile; !$o9:[B  
long nPos; E/ku VZX  
jz&=8  
&hhxp1B  
public FileAccessI() throws IOException Rg~
[X5  
{ WPu%{/[  
this("",0); z5[Qh<M  
} 5M3)7  
i2Gh!5]f  
H{d/%}7[v  
public FileAccessI(String sName,long nPos) throws IOException U.WMu%  
{ k}{K7,DM  
oSavedFile = new RandomAccessFile(sName,"rw"); DB] ]6  
this.nPos = nPos; d k|X&)xTJ  
oSavedFile.seek(nPos); [vCZD8"Y8  
} U:IeMf-;  
:Sk<0VVd7  
3_ =:^Z  
public synchronized int write(byte[] b,int nStart,int nLen) OPKmYzf@b  
{ C9T-4o1  
int n = -1; Rmh,P>  
try{ L w/ZKXDU2  
oSavedFile.write(b,nStart,nLen); MS%h`Ypo  
n = nLen; ?[O Sy.6  
} WOGMtT%  
catch(IOException e) g[xn0rG  
{ y {Mh ?H  
e.printStackTrace (); $4TawFf"nc  
} 2 BwpxV8  
v|>'m#Ln2  
Tj=g[)+K  
return n; GwlAEhP  
} cFG%Ew@  
;\+A6(GX{  
|G-o&m"  
} 'P-FeN^  
RK=YFE 0  
W3i X;-Z  
/* |fm"{$u  
**SiteInfoBean.java IAn/?3a~  
*/ en gh3TZC  
package NetFox; 3^AS8%qG  
z#|tl/aP9  
;,LlOR  
public class SiteInfoBean { `\S~;O  
uwb>q"M  
?Wp{tB9N0  
private String sSiteURL; //Site's URL noNL.%I  
private String sFilePath; //Saved File's Path ~7=w,+  
private String sFileName; //Saved File's Name Wv)2dD2I
 
private int nSplitter; //Count of Splited Downloading File C[(Exe  
`L}Irt}  
N+ R/ti  
public SiteInfoBean() 6~Xe$fP(  
{//nSplitter的缺省值为5 ?x &"EhA>  
//default value of nSplitter is 5 @AkD-}^[  
this("","","",5); dCMWv~>  
} ~4~>;e  
kv3jbSK
CT  
[mk!]r  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0IjQqI  
{ "Mmvf'N  
sSiteURL= sURL; /!0{9F<  
sFilePath = sPath; jCbxI^3A  
sFileName = sName; .W%{j()op  
this.nSplitter = nSpiltter; |"a%S,
I'  
o%tvwv  
<El6?ml@  
}  kQm\;[R  
TXQY&7  
Kth^WHL  
public String getSSiteURL() x:Kca3pv_  
{ fM)RO7  
return sSiteURL; P/FO,S-V  
} #fYz367>  
bKH8/*Yk  
nZM|8  
public void setSSiteURL(String value) yf7p0;$?  
{ N8l(m5Kk,k  
sSiteURL = value; ';!02=-@  
} 5lC"10  
/z+}xRS  
t=ry\h{Pc  
public String getSFilePath() < F Cr L  
{ O<h`[1eUjS  
return sFilePath; ;dYpdy  
} m:~s6c6H  
EmR#)c~(W  
?<slB>8  
public void setSFilePath(String value) =lG5Kc{B  
{ 8f|  
sFilePath = value; 0Q5ua`U  
} -K)P|'-?m  
g=:C/>g  
`7|v  
public String getSFileName() D|n`9yv a  
{ CtA0W\9w5a  
return sFileName; 3u8HF-  
} L+s,,k  
Os1(28rl  
/5_!Y>W  
public void setSFileName(String value) p_QL{gn  
{ fF8g3|p:  
sFileName = value; ^YKEc0"w(  
} }45&s9m=  
([ xYOxcp5  
W%.Kr-[?`o  
public int getNSplitter() ^r$P&}Z\b  
{ mi3yiR  
return nSplitter; ;^FV  
} C;;dCsiV5  
pFD L5  
-$4
PY,  
public void setNSplitter(int nCount) F,`y_71<  
{ 69,;=  
nSplitter = nCount; @K]D :MSS  
} r!etj3  
} c0jC84*v  
=8fp4#]7  
dM7-,9Vc  
/* Vo"\nj  
**Utility.java \ey3i(
(L  
*/ Ssr P  
package NetFox; 6546"sU  
;e_n7>'#%  
^'C1VQ%  
public class Utility { ; eq^m,oz  
0AFjO)  
>e"CpbZ'  
public Utility() Wgdij11e  
{ 6`{Y#2T  
q?{wRBVVB  
4jj@"*^a  
} k|nv[xY0  
c ++tk4  
//线程睡眠 .QzHHW4&0  
public static void sleep(int nSecond) *9((b;Ju  
{ RpR;1ktF>  
try{ QkwBw^'_5  
Thread.sleep(nSecond); 7\K=8G  
} 3j(GcR9  
catch(Exception e) z6b
!,lp  
{ <`b)56v:+  
e.printStackTrace (); U*=ebZno  
} 9=~"^dp54%  
} Y_)!U`>N?  
c:4M|t
=  
//日志 *K'(t  
public static void log(String sMsg) `$7j:<c=  
{ O!kBp(?]  
System.err.println(sMsg); f 6Bx>lh  
} ; 7[
5%xM  
`TOm.YZG  
@%fNB,H`
 
public static void log(int sMsg) gyJ$Jp  
{ &mKtW$K` q  
System.err.println(sMsg); \;}F6g  
} )&<BQIv9/  
} me#
VCkr#  
_JiB=<Fkr  
'q8T*|/  
/* uMtq4.  
**TestMethod.java $3|++?  
*/ :aR&t#<"E  
package NetFox; r%JJ5Al.S  
yNP M-  
Z~ VOO7|m  
public class TestMethod { r'uD|T H  
Oj6-  
YgCJ s;  
public TestMethod() 0$%:zHi5g  
{ ///xx/weblogic60b2_win.exe dQQh$*IL?{  
try{ (2Z-NVU#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); W
rQe'ny  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c%yhODq/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %,E\8{I+  
fileFetch.start(); VChNDHiH  
} )"2)r{7:  
catch(Exception e){e.printStackTrace ();} vX;WxA<  
#TM+Vd$  
Lf{9=;  
} /mX/ "~  
_$]3&P  
] hGU.C"(  
public static void main(String[] args) u;GS[E4  
{ i<l_z&  
new TestMethod(); K2<"O qp_W  
} ;"$Wfy  
} 0qqk:h  
点击下载更多相关资料