http断点续传简单实现（java)

/* |bM?Q$>~  
**SiteFileFetch.java ^}{`bw{  
*/ ]nQC  
package NetFox; -LnNA`-  
import java.io.*; -]-?>gkN5  
import java.net.*; `at>X&Ce,  
AnW72|=A(  
u 6"v}gN  
public class SiteFileFetch extends Thread { nuucYm%IF-  
!]l!I9  
)zMsKfQ  
SiteInfoBean siteInfoBean = null; //文件信息Bean |9;MP&68  
long[] nStartPos; //开始位置 qN@-H6D1=  
long[] nEndPos; //结束位置 _yu_Ev}R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }~bx==SF6!  
long nFileLength; //文件长度 1=^edQ+  
boolean bFirst = true; //是否第一次取文件 BIn7<.&  
boolean bStop = false; //停止标志 ][[\!og  
File tmpFile; //文件下载的临时信息 -udKGrT+  
DataOutputStream output; //输出到文件的输出流 n
B.u5  
B4/\RC2  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Z]\IQDC  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?>}&,:U}  
{ MVYf-'\^
  
siteInfoBean = bean; 5n#@,V.O/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a'prlXr\4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); IS[&V&.n  
if(tmpFile.exists ()) -+H?0XN  
{ "l7))>lL  
bFirst = false; dp=#|!jc  
read_nPos(); G@+AB*Eu  
} Lk8NjK6  
else 8EC$p} S  
{ O@)D%*;v  
nStartPos = new long[bean.getNSplitter()]; &"/IV$H  
nEndPos = new long[bean.getNSplitter()]; 0'nY
 
} c%O8h  
.G/2CVM
j  
,nnVHBN  
`ZLA=oD  
} ;z3w#fNMv  
tEC`
->|  
Xt%>
XP  
public void run() WVkJ=r0Ny  
{ ;qwNM~  
//获得文件长度 >ZjGs8&  
//分割文件 8^
U
+P%  
//实例FileSplitterFetch YgCSzW&(  
//启动FileSplitterFetch线程 cd-;?/  
//等待子线程返回 TD"w@jBA  
try{ "i1r9TLc  
if(bFirst) meM61ue_2  
{ KU5|~1t 4  
nFileLength = getFileSize(); )m4O7'2G  
if(nFileLength == -1) o?]g  
{ 9+"\7MHw  
System.err.println("File Length is not known!"); mq!_/3  
} W%&'EJ)62  
else if(nFileLength == -2) zZ})$Ny(  
{ !-<PV  
System.err.println("File is not access!"); !^*-]
p/z  
} WY`hNT6M  
else oHvVZ  
{ $9In\x
  
for(int i=0;i<nStartPos.length;i++) \Bg?QhA_D  
{ `xm4?6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); j?gscQ3  
} Q4!6|%n8v  
for(int i=0;i<nEndPos.length-1;i++) Smjg[  
{ 48t_?2>  
nEndPos = nStartPos[i+1]; =j$!N# L  
} /
GDGE }  
nEndPos[nEndPos.length-1] = nFileLength; ET:B"  
} Q?7:XbN  
} B(l8&  
GT(nW|v  
C?h`i ^ >2  
//启动子线程 UW@BAj@^@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #nS[]UbwZ  
for(int i=0;i<nStartPos.length;i++) 0*umf.R  
{ xZpGSlA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %^VQw!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9p '#a:  
nStartPos,nEndPos,i); szG0?e  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *LZ^0c:r  
fileSplitterFetch.start(); vi-mn)L6#  
} n>["h2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =3= $F%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @ApX43U(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", A=a~ [vre  
nEndPos = " + nFileLength); -|\SNbPTV  
// fileSplitterFetch[nPos.length-1].start(); r@9qjva  
InCo[ 8SI  
\Tii S  
//等待子线程结束 4Bc<  
//int count = 0; %J%ZoptY:  
//是否结束while循环 8/16<yZ  
boolean breakWhile = false; &:MfLDJ  
@*{sj`AS '  
F>!gwmn~  
while(!bStop) )VoQ/ch<  
{ <6L=% \X{*  
write_nPos(); ;;cPt44s
 
Utility.sleep(500); qZ79IX'y  
breakWhile = true; bo%v(  
oY$L  
fj,]dQT  
for(int i=0;i<nStartPos.length;i++) <z+b88D  
{ M(+;AS?;  
if(!fileSplitterFetch.bDownOver) 0*-nVC1  
{ RxZ#`$F  
breakWhile = false; 3$hbb6N%6.  
break; gY=Ry=w9  
} nL[zXl  
} sHwn,4|iY  
if(breakWhile) .xIu  
break; 5PXo1"n8T  
./!6M  
_s> ZY0  
//count++; }[%d=NY  
//if(count>4) ])YGeY(V0+  
// siteStop(); m=7Z8@sX},  
} vKC
gtk  
J|D$  
^& R H]q  
System.err.println("文件下载结束！"); "BAH=ul5E  
} y?1<7>L5~  
catch(Exception e){e.printStackTrace ();} QxjX:O  
} nR()ei^X  
/e0cx:.w  
qauZ-Qoc9  
//获得文件长度 :1O1I2L0  
public long getFileSize() /V%]lmxQ  
{ Z
;XiA<|  
int nFileLength = -1; AvNU\$B4aG  
try{ <P"4Mk7`s  
URL url = new URL(siteInfoBean.getSSiteURL()); ;& PK6G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yXdJ5Me(T  
httpConnection.setRequestProperty("User-Agent","NetFox"); G L> u3K  
5cza0CriJ  
RC']"jpW  
int responseCode=httpConnection.getResponseCode(); xn)eb#r  
if(responseCode>=400) l`}Ag8Q  
{ $)fybnY  
processErrorCode(responseCode); EC6Q<&]Iw  
return -2; //-2 represent access is error 1p[Z`m*9  
} dT9ekNQB  
5r$X  
+z2+z  
String sHeader; .PhH|jrCW^  
-#nfO*H}  
ERE1XOe=D  
for(int i=1;;i++) jW G=k#WN  
{ /W,K% s]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `S{Blv  
//Utility.log(in.readLine()); R1%2]?  
sHeader=httpConnection.getHeaderFieldKey(i); 22<T.c  
if(sHeader!=null) u?>]C6$  
{ v\UwL-4
[  
if(sHeader.equals("Content-Length")) vj23j[!|  
{ Q.8)_w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $YM6}D@  
break; +C(v4@=nd  
} 4p%=8G|  
} bBFdr  
else !w[io;  
break; :Gdfpz-{?  
} us^2Oplq<  
} N{f4-i~  
catch(IOException e){e.printStackTrace ();} u*<G20~A  
catch(Exception e){e.printStackTrace ();} K^_Mt!%  
jb~/>I^1  
H$/r{gfg^  
Utility.log(nFileLength); A?q9(n|A"  
nv9kl Q@  
+cw;a]o^>  
return nFileLength; sPee"9
%,  
} }5)sS}C  
SgOn:xg;3L  
Z!qHL$  
//保存下载信息（文件指针位置） i'Oh^Y)E#  
private void write_nPos() j3
W)5ZX  
{ E!eBQ[@  
try{ UBUZ}ZIbN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); pzMli^  
output.writeInt(nStartPos.length); y'9 bs  
for(int i=0;i<nStartPos.length;i++) &m'ttUG?  
{ ?d -$lI  
// output.writeLong(nPos); dtdz!'q)Y  
output.writeLong(fileSplitterFetch.nStartPos); ~\9bh6%R  
output.writeLong(fileSplitterFetch.nEndPos); CS:mO|  
} "z^&>#F  
output.close(); !lf:x  
} zLs[vg.(  
catch(IOException e){e.printStackTrace ();} }/%(7Ff{  
catch(Exception e){e.printStackTrace ();} 2{!^"iW  
} 4gTDHQP  
QX*HvT  
8G>;X;W  
//读取保存的下载信息（文件指针位置） l+>&-lX'  
private void read_nPos() ?T\m V}  
{ I.<>6ISI@  
try{ 0#}@-e  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6E!CxXUX  
int nCount = input.readInt(); Q&Rj)1!  
nStartPos = new long[nCount]; 0nF>E@j^[  
nEndPos = new long[nCount]; mxYsP6&  
for(int i=0;i<nStartPos.length;i++) 2[\I{<2/9  
{ 7DU"QeLeb  
nStartPos = input.readLong(); qq&G~y  
nEndPos = input.readLong(); rf%E+bh4  
} ,Z7tpFC  
input.close(); ?s<'3I{F`  
} dnby&-+T  
catch(IOException e){e.printStackTrace ();} BVx: JiA  
catch(Exception e){e.printStackTrace ();} %C]K`=vI-  
} .Qpqbp 8  
HqW|  
kQR
kby  
private void processErrorCode(int nErrorCode) X^PR];V:$  
{ 
HS|X//]  
System.err.println("Error Code : " + nErrorCode); N{]|
!#  
} {e4ILdXM  
f!`,!dZgkd  
n')#]g0[  
//停止文件下载 E
V:y}  
public void siteStop() ("t; 2Mw  
{ c1IK9X*  
bStop = true; u3 mTsq!  
for(int i=0;i<nStartPos.length;i++) o9!DK  
fileSplitterFetch.splitterStop(); UGy~Ecv  
vG'JMzAm  
<t{T]i+  
} v'C`;I  
} rNL*(PN}lO  
//负责部分文件的抓取 U!"+~d)  
**FileSplitterFetch.java ,6Kx1
 c  
*/ 9HOdtpQOV  
package NetFox; BfLh%XC  
Y&O<A8=8  
I9ga8mG4-'  
import java.io.*; M]?#]3XBNo  
import java.net.*; "+js7U-  
Bv^{|w  
P`'
Nv  
public class FileSplitterFetch extends Thread { Nb[z+V{=  
7Q<xC  
3*G7H  
String sURL; //File URL .1u"16_  
long nStartPos; //File Snippet Start Position <;d?E%`  
long nEndPos; //File Snippet End Position Kq|L:Z  
int nThreadID; //Thread's ID
GM6Y`iU  
boolean bDownOver = false; //Downing is over y ?FKou'  
boolean bStop = false; //Stop identical %f.(^<Gu  
FileAccessI fileAccessI = null; //File Access interface V4GcW|P4y  
eKlh }v  
0kI.dX)  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException bJD2c\qoc  
{ TxYxB1C)  
this.sURL = sURL; #c V_p  
this.nStartPos = nStart; }bG|(Wp9  
this.nEndPos = nEnd; nT0FonK>  
nThreadID = id; @0q%&v0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o$4n D#P3  
} L Ty[)  
bz[+g,e2oA  
Be{7Rj v  
public void run() X I\zEXO  
{ {]~b^=qE$  
while(nStartPos < nEndPos && !bStop) uE~? 2G  
{ odPq<'V|AY  
[-cYFdt"V  
&N!QKrj3  
try{ 317Lv \[  
URL url = new URL(sURL); 4/$ $?w4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v\#69J5.>)  
httpConnection.setRequestProperty("User-Agent","NetFox"); oB:tio4DE  
String sProperty = "bytes="+nStartPos+"-"; F/[vg  
httpConnection.setRequestProperty("RANGE",sProperty); ^'=J'Q  
Utility.log(sProperty); c+/SvRx^>  
NZ/>nNs  
RsS?ibozl  
InputStream input = httpConnection.getInputStream(); SrfDl*  
//logResponseHead(httpConnection); D+/27#
 
tY<D\T  
rrei6$H&  
byte[] b = new byte[1024]; NAjK0]SRY  
int nRead; y&NO[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =$UDa`}D  
{ Kw}-<y  
nStartPos += fileAccessI.write(b,0,nRead); 4,kT4_&,  
//if(nThreadID == 1) Z |uII#lq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'G3B02*  
} :tY;K2wDM  
LuS]D%  
IiV:bHUE}0  
Utility.log("Thread " + nThreadID + " is over!"); p%_#"dkC7  
bDownOver = true; F{\MIuoy  
//nPos = fileAccessI.write (b,0,nRead); -.:[a3c?  
} g4<w6eB  
catch(Exception e){e.printStackTrace ();} dOArXp`s  
} +1Oi-$ 2-  
} [G^ir  
$VYMAk&\  
`#hdb=3  
//打印回应的头信息 NrVrR80Y  
public void logResponseHead(HttpURLConnection con) WC,&p  
{ *upl*zFf0  
for(int i=1;;i++) f{[U->#^  
{ s4bL
L  
String header=con.getHeaderFieldKey(i); T_O\L[]p*  
if(header!=null) MV5'&" ,oB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); s{#ZRmc2B  
Utility.log(header+" : "+con.getHeaderField(header)); ++-\^'&1  
else 0n+Wv@/  
break; M@S6V7  
} CF3Z`xD  
} }wrZP}zM>  
,{A-<=6t  
;JMd(\+-  
public void splitterStop() j"*ZS'0  
{ mXT{)pU  
bStop = true; G<,@|6"w  
} f_X]2in  
r'M|mQ$s>  
FMB\$(g  
} oop''6`C%  
IC>OxYg*  
306C_M\$  
/* CXGq>cQ=d  
**FileAccess.java u1O?
`  
*//文件访问(定位，写) E~]8>U?V  
package NetFox; ^HumyDD6  
import java.io.*; ^
EE3E'  
Y[9x\6 _E  
RG-pN()  
public class FileAccessI implements Serializable{ ~sk;6e)(2  
]Qe;+p9vU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  B\1F  
RandomAccessFile oSavedFile; g<O*4 ]=  
long nPos; -Y
%#z'^-  
{XiBRs e  
ncf=S(G+  
public FileAccessI() throws IOException )s(J8J[b*L  
{
,Khhu%$  
this("",0); N7k<q=r-  
} *xXa4HB  
y% =n
hV  
nY"9"R\.=  
public FileAccessI(String sName,long nPos) throws IOException @47MJzC  
{ ^Afq)26D  
oSavedFile = new RandomAccessFile(sName,"rw"); |&WeXVH E  
this.nPos = nPos; 7. 9n  
oSavedFile.seek(nPos); ;|e{J$  
} qYc]Y9fi  
72@raA#
y  
\k_0wt2x1  
public synchronized int write(byte[] b,int nStart,int nLen) :<4:h.gO8  
{ FW(y#Fmqs  
int n = -1; rVq=,>M9  
try{ T1c2J,+}R  
oSavedFile.write(b,nStart,nLen); mw";l$Aq}  
n = nLen; C
,+6g/{  
} nJ |O,*`O  
catch(IOException e) T;X8T  
{ X64OX9:YF  
e.printStackTrace (); [TvH7ott'1  
} X*VHi  
R:kNAtK  
\ Xow#@[  
return n; E6|!G  
} >tXn9'S  
O79;tA<k
 
F@4XORO;  
} KB!.N[!v  
My0h9'K  
u{xjFx-  
/* O= PFr"  
**SiteInfoBean.java 0{g@j{Lbz  
*/ I^sWf3'db  
package NetFox; T
DXLxoC?  
"&%: 9O  
5*~Mv<#  
public class SiteInfoBean { $8h
^R#  
}C.M4{a\  
W@v@|D@  
private String sSiteURL; //Site's URL 4thLK8/c5g  
private String sFilePath; //Saved File's Path q3Re F_  
private String sFileName; //Saved File's Name p*)R

P2  
private int nSplitter; //Count of Splited Downloading File uhvmh  
N r5 aU6]  
jC>l<d_  
public SiteInfoBean() rXXIpQRi$S  
{//nSplitter的缺省值为5 [,)yc/{*  
//default value of nSplitter is 5 De,4r(5  
this("","","",5); @=q,,t$r  
} Vd^_4uqnV  
5f2ah4 g  
t_5b  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cy8+
@77  
{ .f 4a+w  
sSiteURL= sURL; }q9;..oL  
sFilePath = sPath;
"ut:\%39.  
sFileName = sName; 68?oV)fE  
this.nSplitter = nSpiltter; 4a]m=]Hm  
4&;.>{:;  
B8-v!4b0`  
} zlzr;7m  
N8|=K_;&  
hM\<1D CKG  
public String getSSiteURL() CLU!/J$!  
{ {^gbS  
return sSiteURL; AEaT  
} &WAO.*:y  
x"h0Fe?J  
:" Q!Q@>  
public void setSSiteURL(String value) j|gv0SI_ w  
{ i
aO;i1K5U  
sSiteURL = value; , "w`,c>!  
} V0+D{|thh6  
f)hs>F  
flp<QT  
public String getSFilePath() D7cOEL<  
{ z!27#
gbL  
return sFilePath; aCzdYv\}&  
} ""l_&3oz  
<y1V2Np  
LcCb[r  
public void setSFilePath(String value) +cv7]  
{ ;Vc@]6Ck  
sFilePath = value; 6dQa|ACX_  
} Icf 4OAx  
#+Z3!VS  
2xRb$QF  
public String getSFileName() uV.3g 1m  
{ ?PORPv#
 
return sFileName; eA9U|&o  
} <Ur(< WTV  
E< nXkqD  
v<iMlOEt  
public void setSFileName(String value) >ijFQ667>j  
{ yO.3~H)c  
sFileName = value; +;SQ}[  
} o<P@:}K  
a*JM2^,HO  
|,M&ks  
public int getNSplitter() r*]0PQ{?  
{ lQQXV5NV  
return nSplitter; x bF*4;^SI  
} ;;'b;,/  
Ry*NRP;  
-}|GkTM  
public void setNSplitter(int nCount) OD<0,r0f,  
{ tdg.vYMDPC  
nSplitter = nCount; W Da;wt  
} I7b(fc-r  
} ZxkX\gl91  
,t5X'sY L  
*9)7.}uY  
/* 'Y3
>+7bI  
**Utility.java _.0c~\VA  
*/ aVvi_cau  
package NetFox; p'1n'|$e  
E 5}T_~-{  
Im%|9g;P  
public class Utility { UI|L;5  
ie+&@u  
<b"ynoM.
A  
public Utility() P;0tI;  
{ c.jq?
Q k  
8}h ^Frh  
h-hU=I8  
} hKjvD.6]%  
6'ye-}vD-  
//线程睡眠 ;`g\Tu  
public static void sleep(int nSecond) Pi::cf>3  
{ Yu=4j9e_mG  
try{ -H~g+i*J  
Thread.sleep(nSecond); >R3~P~@30  
} _H^Ij  
catch(Exception e) x-+[gNc 6  
{ vFY/o,b \  
e.printStackTrace (); pW O-YZ#+  
} D4'"GaCv  
} mtuq  
g(<02t!OT=  
//日志 m3XL;1y:a  
public static void log(String sMsg) B#o(21s  
{ Dr6"~5~9w  
System.err.println(sMsg); V[,/Hw~d%  
} WpC@nz?  
3P Twpq1  
"lLt=s2>L  
public static void log(int sMsg) zNR
oFz.  
{ (u85$
_C  
System.err.println(sMsg); K1uN(T.Ju  
} 6,M>'s,N  
} w_G/[R3  
,$5;  
@va{&i`%A7  
/* ZmO/6_nU?  
**TestMethod.java ?6Cbx6  
*/ Gdnk1_D>  
package NetFox; wE3^6  
ba|x?kz  
)/2* <jr  
public class TestMethod { R
0+v5E  
AC,$(E  
4
?M=?K0  
public TestMethod() Mo &I
a6^  
{ ///xx/weblogic60b2_win.exe #O]F5JB  
try{ &w:"e'FG`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0:Js{$ZL4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "-XL Y_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aAO[Y"-:,Y  
fileFetch.start(); q
hVDC  
} KL*ZPKG  
catch(Exception e){e.printStackTrace ();} N^q*lV#kob  
+xRja(d6  
3O%[k<S\VO  
} liFNJd`|o+  
G,>tC`!  
/a17B  
public static void main(String[] args) =sedkrM  
{ 8<3J!X+  
new TestMethod(); _Pa(5-S'KR  
} D9e"E1f+"  
} }r`!p5\$K0  
点击下载更多相关资料