http断点续传简单实现（java)

/* @hz0:ezg:  
**SiteFileFetch.java iYmzk?U  
*/ { 8|Z}?I  
package NetFox; +lXdRc`6  
import java.io.*; }AeE|RNc  
import java.net.*; Rzn0-cG  
eF gb6dSh  
>k&lGF<nl  
public class SiteFileFetch extends Thread { D; 35@gtj  
tZc.%TU  
0 6G[^  
SiteInfoBean siteInfoBean = null; //文件信息Bean s/p>30Fg  
long[] nStartPos; //开始位置 aF4V|?+  
long[] nEndPos; //结束位置 [K|>s(Sf*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5D02%U2N)G  
long nFileLength; //文件长度 B2Awdw3=g  
boolean bFirst = true; //是否第一次取文件 MIMPJXT#.  
boolean bStop = false; //停止标志 9O0  
File tmpFile; //文件下载的临时信息 =:R[gdA#1  
DataOutputStream output; //输出到文件的输出流 *M**h-p2'  
2Yg[8Tm#  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "351s3ff  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1PT_1[eAR  
{ (/rIodHJO  
siteInfoBean = bean; uBL~AC3>O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /v5g;x
_T
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Q/9vDv  
if(tmpFile.exists ()) 5IF~]5s  
{ ]qP}
\+:  
bFirst = false; iTBhLg,  
read_nPos(); b\uB  
} }?ac<> u&  
else /-<m(72wF  
{ pa> 2JF*  
nStartPos = new long[bean.getNSplitter()]; #}]il0d  
nEndPos = new long[bean.getNSplitter()]; [8J}da}  
} p=5H^E m1  
gu%'M:Xe  
@snLE?g j  
A,CPR0g%  
} p-03V"^&  
h,jAtL!  
}T*xT>p^3  
public void run() O=?X%m #  
{ 8LM1oal}  
//获得文件长度 w!9WCl]9M  
//分割文件 ke6cZV5w  
//实例FileSplitterFetch 36Y[7m=  
//启动FileSplitterFetch线程 r#Oz0=0u  
//等待子线程返回 *gpD4c7A\  
try{ FoXQ]X7"  
if(bFirst) `j"G=%e3.  
{ xr-`i  
nFileLength = getFileSize(); qO3BQ]UF  
if(nFileLength == -1) Z1lF[d,f;  
{ %L|bF"K5;  
System.err.println("File Length is not known!"); {EHG |  
} "^e?E:( 3  
else if(nFileLength == -2) ]mT} \b  
{ :T
y*
i  
System.err.println("File is not access!"); =]mx"0i[  
} e(% Solkm?  
else `-YSFQ~O,  
{ |(ju!&  
for(int i=0;i<nStartPos.length;i++) X35U!1Y\  
{ ~TR|Pv  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oi4Wxcj  
} 0!\q
  
for(int i=0;i<nEndPos.length-1;i++) 4'b]2Mn3   
{ '*Mb .s"  
nEndPos = nStartPos[i+1]; ~"0
X,APR5  
} 0lh6b3tdP  
nEndPos[nEndPos.length-1] = nFileLength; wz)9/bL  
} X[Gk!dr#  
} :Aiu!}\  
,T[ +omo  
"(VcYQ+  
//启动子线程 ]7 mSM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; M.^A`  
for(int i=0;i<nStartPos.length;i++) $s!meg@s  
{ PzkXrDlB7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *9wHH-#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q8:ocEhR  
nStartPos,nEndPos,i); bu9&sQ;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PdBhX  
fileSplitterFetch.start(); ID+k`nP  
} #;]F:TlR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kovzB]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =6YO!B>7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Yk&{VXU<  
nEndPos = " + nFileLength); MX\-)e#  
// fileSplitterFetch[nPos.length-1].start(); xhS/X3<th  
ENjD~S  
uelTsn  
//等待子线程结束 EIm\!'R]  
//int count = 0; R?SHXJ%'  
//是否结束while循环 cLP@0`^H  
boolean breakWhile = false; 4=:eGlU93U  
83*k.]S`  
Jz'+@q6h  
while(!bStop) z59J=?|  
{ _S1uJ~j;E  
write_nPos(); 9%6`ZS~3  
Utility.sleep(500); ^u,x~nPXg  
breakWhile = true; XS/TYdXB8  
*X=-^\G  
e84TLU?~  
for(int i=0;i<nStartPos.length;i++) Vrh],xK7  
{ RVnYe='  
if(!fileSplitterFetch.bDownOver) .x%SbG<k{  
{ {NDP}UATw  
breakWhile = false; a|
cD{d  
break; &0`7_g7G  
} :[3\jLrc  
} 8ipLq`)  
if(breakWhile) g2q=&eI"  
break; mo$*KNW%\  
cqp#1oM4M  
$)V4Eu;  
//count++; JK`P mp>  
//if(count>4) +dv@N3GV  
// siteStop(); 'h6RZKG T  
} X
Q8Imkc  
A>puk2s  
h@d m:=ul  
System.err.println("文件下载结束！"); jFfki.H  
} [4e5(!e  
catch(Exception e){e.printStackTrace ();} p2K9R4  
} H"l'E9k.&p  
 tS7u#YMh  
#v-!GK_<  
//获得文件长度 W]OT=6u8o  
public long getFileSize() kn\>ZgU  
{ b'YbHUyu  
int nFileLength = -1; =qRVKz  
try{ x3 S
 
URL url = new URL(siteInfoBean.getSSiteURL()); Y<v55m-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); icmDPq  
httpConnection.setRequestProperty("User-Agent","NetFox"); u+_#qk0NfK  
[6|vx},N  
Qp
,l>k  
int responseCode=httpConnection.getResponseCode(); $BY{:#a]  
if(responseCode>=400) _c2#  
{ \2jY)UrQs  
processErrorCode(responseCode); *)<tyIHd  
return -2; //-2 represent access is error 7-DC"`Y8e  
} w3@te\  
2wd(0K}b  
_,^sI%  
String sHeader; $gNCS:VG*  
MYDSkW  
Y"@kvd  
for(int i=1;;i++) e9d~Xi16KY  
{ }W<L;yD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); mI# BQE`p6  
//Utility.log(in.readLine()); ~#@EjQCq  
sHeader=httpConnection.getHeaderFieldKey(i); 7@FB^[H:y  
if(sHeader!=null) 9O"?T7i"#  
{ ;IT^SHym  
if(sHeader.equals("Content-Length")) ~&x%;cnv_  
{ 1 wG1\9S  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v09f#t$;5  
break; pqe**`z@y  
} X'c5s~9  
} -n9e-0  
else 9c6=[3)V  
break;
Ssj'1[%  
} .\VjS^o&Z&  
} uMI2Wnnc:/  
catch(IOException e){e.printStackTrace ();} yS*PS='P  
catch(Exception e){e.printStackTrace ();} ?vVkZsU  
+3C S3fTq  
"#7i-?=  
Utility.log(nFileLength); G 1$l%B  
+FiV!nRkZ  
MWl@smRh  
return nFileLength; G<-.{Gx)  
} x\jHk}Buj  
3 *G=U  
gDsZb
mR  
//保存下载信息（文件指针位置） "rXGXQu  
private void write_nPos() [D t`@Dm  
{ ^T5c^ M8o  
try{ ; H3kb +  
output = new DataOutputStream(new FileOutputStream(tmpFile));
BXdT;b"J(  
output.writeInt(nStartPos.length); 3EyN"Lvp{o  
for(int i=0;i<nStartPos.length;i++) 2d._X$fx7  
{ en  
// output.writeLong(nPos); +|.#<]GA  
output.writeLong(fileSplitterFetch.nStartPos); {\V)bizY;  
output.writeLong(fileSplitterFetch.nEndPos); K)qmJ-Gub  
} eN$~@'w  
output.close(); _ehU:3L`s  
} y?rsfIth`  
catch(IOException e){e.printStackTrace ();} -X=f+4j  
catch(Exception e){e.printStackTrace ();} yqK82z5U*R  
} .Ybm27Dk  
!O5UE  
S2*:]pYf}  
//读取保存的下载信息（文件指针位置） +z4NxR   
private void read_nPos() C{c (K!  
{ 4QDW}5xB  
try{ &8;mcM//4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j#*K[  
int nCount = input.readInt(); y|@^0]}%<  
nStartPos = new long[nCount]; #*9*[Xbi  
nEndPos = new long[nCount]; / g&mDYV|  
for(int i=0;i<nStartPos.length;i++) ]\jhtC=2  
{ 9Kqr9U--v  
nStartPos = input.readLong(); ZFRKh:|  
nEndPos = input.readLong(); 9A6ly9DIS  
} x[vX|oE!A  
input.close(); d`:0kOF+  
} pZH bj2~  
catch(IOException e){e.printStackTrace ();} >uQ!B
/C!  
catch(Exception e){e.printStackTrace ();} J|ILG  
} @<};Bo'  
P$!Ht  
'aCnj8B  
private void processErrorCode(int nErrorCode) `xtN+y F  
{ -<|Ebh d3  
System.err.println("Error Code : " + nErrorCode); t'z]<7  
} i P/I% D  
,@P3!|  
=^{^KHzIl3  
//停止文件下载 o&>0 pc  
public void siteStop() rp _G.C  
{ LIR2B"3F  
bStop = true; \,?yj  
for(int i=0;i<nStartPos.length;i++) =B;)h  
fileSplitterFetch.splitterStop(); K
46mE   
sT/pA^rnnR  
YKk%lZ.8  
} C&"8A\we  
} nrZv>r  
//负责部分文件的抓取 wngxVhu8Ld  
**FileSplitterFetch.java @ #V31im"N  
*/ (V |P6C  
package NetFox; p,xM7V"O)  
>Vn!kN6\  
6z/8nf +u  
import java.io.*; (+4=A k  
import java.net.*; /1O6;'8He  
SBYRN##n_  
w|>Y&/IX  
public class FileSplitterFetch extends Thread { -,Q<*)q{  
PZ"xW0"-  
?Ww',e  
String sURL; //File URL YrB-;R1+  
long nStartPos; //File Snippet Start Position FL`. (,  
long nEndPos; //File Snippet End Position of(Nq@  
int nThreadID; //Thread's ID J,E&Uz95%  
boolean bDownOver = false; //Downing is over `5>IvrzXrK  
boolean bStop = false; //Stop identical PY`V]|J  
FileAccessI fileAccessI = null; //File Access interface E6n;_{Se/S  
8y+Gvk:  
xNjA>S\]W5  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +[*UC"  
{ |px4a"  
this.sURL = sURL; y_J{+  
this.nStartPos = nStart; Ju:=-5r"'  
this.nEndPos = nEnd; ^up*KQ3u\  
nThreadID = id; N["(ZSS   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :s8,i$Ex  
} "i#!  
<nIU]}q  
n)pBK>+  
public void run() uZ OUp8QQ  
{ pKp#4Js  
while(nStartPos < nEndPos && !bStop) L!{^^7  
{ %S@XY3jZY  
9WBDSx_(Q  
|z5olu$gVc  
try{ !rrjA$P<v  
URL url = new URL(sURL); M`"2;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I</Nmgf  
httpConnection.setRequestProperty("User-Agent","NetFox"); c5U1N&k5&  
String sProperty = "bytes="+nStartPos+"-"; 9N9|hy  
httpConnection.setRequestProperty("RANGE",sProperty); hf%W grO.  
Utility.log(sProperty); ib& |271gG  
Q>||HtF$A  
)L_jR%2j  
InputStream input = httpConnection.getInputStream(); Rov0  
//logResponseHead(httpConnection); +!w?g/dV  
#Xsby  
dU+1@_  
byte[] b = new byte[1024]; ,(lD5iN  
int nRead; Q}I.UG_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;M}bQ88  
{ 2Q<_l*kk(  
nStartPos += fileAccessI.write(b,0,nRead); !n !~Bw  
//if(nThreadID == 1) />]/At  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }~\J7R'  
} S$V'_  
a3p|>M6E  
LZ^sc  
Utility.log("Thread " + nThreadID + " is over!"); _gU[FUBtJ  
bDownOver = true; r}XD{F}"  
//nPos = fileAccessI.write (b,0,nRead); vR:t4EJ`  
} q!NwfXJM  
catch(Exception e){e.printStackTrace ();} igz&7U8gg  
} /@on=~  
} >R.~'A/$F  
;/ p)vR  
{%~Sbcq4F  
//打印回应的头信息 bp5hS/A^1w  
public void logResponseHead(HttpURLConnection con) k9Yr&8B  
{ Z73 ysn}  
for(int i=1;;i++) ]>x674H  
{ 1q/z&@+B  
String header=con.getHeaderFieldKey(i); JlGyGr^MD  
if(header!=null) k \]@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Be-gGJG  
Utility.log(header+" : "+con.getHeaderField(header)); =(zk-J<nY  
else `(16_a  
break; G.cs-f  
} GVFD_;j'  
} bx`(d
@  
40+E#z)  
48w3gye  
public void splitterStop() tjYe82  
{ ~*G I<n  
bStop = true; +)ro EJ_  
} $YL}rM  
a'Aru^el  
~>
)cY{wE_  
} '0?5K0 2(  
k98-
-kc5  
+]UPY5:F  
/* A.y
"R)G  
**FileAccess.java 7!Fu.Ps >  
*//文件访问(定位，写) R-Uj\M>  
package NetFox; v]vrD2L  
import java.io.*; oSE'-8(  
@p}H@#/u\  
{"s9A&  
public class FileAccessI implements Serializable{ Y$Fbi2A4  
]}C#"Xt  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ./.E=,j  
RandomAccessFile oSavedFile; wxvt:==  
long nPos; T,jxIFrF  
zoO>N'b3)  
u!;kBs  
public FileAccessI() throws IOException #F[6$. Gr  
{ Cc9<ABv?  
this("",0); Bg;bBA!L  
} b>;5#OQfn  
l--xq^,`o]  
r+\it&cW+  
public FileAccessI(String sName,long nPos) throws IOException Bxz{rR0XV  
{ -08Ys c  
oSavedFile = new RandomAccessFile(sName,"rw"); h&[!CtPm  
this.nPos = nPos; {h
VSVx8ZL  
oSavedFile.seek(nPos); <9B43  
} wgfn:LR  
jhK&Z7;  
^Fy) oWS  
public synchronized int write(byte[] b,int nStart,int nLen) Tf*X\{"  
{ )HR'FlxOd  
int n = -1; t+p-,ey^@  
try{ 0d.lF:  
oSavedFile.write(b,nStart,nLen); Cl i k  
n = nLen; -O. MfI+  
} pHKj*Y  
catch(IOException e) )Z"7^i  
{ k' pu%nWN  
e.printStackTrace (); l&
5| =  
} q0SvZw]f1  
7|IW\  
H`B%6S/  
return n; Zb8i
[1P  
} 0+M1,?+GfF  
EGU?54  
V?5QpBKI  
} gXs@FhR0  
TY~0UU$  
a]$KI$)e  
/* d.2   
**SiteInfoBean.java o y}(  
*/ 7{/qQGL  
package NetFox; Z A7u66  
r'w5i1C+  
b&V
=X{V4  
public class SiteInfoBean { G74<sD  
fM \T^X  
!X*L<)=nh  
private String sSiteURL; //Site's URL rDm>R
m=  
private String sFilePath; //Saved File's Path cb|`)"<HN  
private String sFileName; //Saved File's Name &UQKZ.  
private int nSplitter; //Count of Splited Downloading File Pbd#Fu;  
$Iv*?S"2  
j@2-^q:`  
public SiteInfoBean() ukvz#hdE  
{//nSplitter的缺省值为5 j^986  
//default value of nSplitter is 5 g)xzy^2e  
this("","","",5); vqv(KsD+::  
} >PL/>   

`hI1  
st'Y j  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ZVgR7+`]#  
{ )QFT$rmX  
sSiteURL= sURL; ;k(|ynXv  
sFilePath = sPath; ~d){7OG  
sFileName = sName; )Q~Q.  
this.nSplitter = nSpiltter; 5N`g  
DpI_`TF#$Z  
?jz{fU  
} |oPqX %?  
uqX"^dn4u  
|`_TVzA  
public String getSSiteURL() $(#o)r>_R  
{ T|Z
T&x$z  
return sSiteURL; z}OY'}sk8  
} &!KJrQ  
# |w,^tV  
 p^\>{  
public void setSSiteURL(String value) [Z~>7ayF+)  
{ +~8/7V22  
sSiteURL = value; >3 qy'lm  
} tJ2l_M^  
g)u2  
r(J7&vR}h  
public String getSFilePath() ^ chlAQz(  
{ ft:/-$&H  
return sFilePath; |) THuE(  
} AUzJ:([V  
0v+5&Jk  
{hZZU8*  
public void setSFilePath(String value) t~,!a?S7  
{ >(:KEA  
sFilePath = value; ?8YHz  
} zSDiJ$Xk  
9FH=Jp  
j%~UU0(J  
public String getSFileName() BU]9eF!>h  
{ @*A(#U8p3  
return sFileName; /rKrnxw  
} #^xiv/sV  

~wh8)rm  
~)sb\o  
public void setSFileName(String value) WoesE:NiR  
{ `'+[Y;s_  
sFileName = value; z$%ntN#eNA  
} F RS@-P  
H)t8d_^|j  
vA(3H/)-  
public int getNSplitter() &$< S1  
{ VEE:Z^U!  
return nSplitter; PyzWpf  
} 9.SPxd~  
pz.<5  
j31 Sc3vG  
public void setNSplitter(int nCount) yd`.Rb&V  
{ f0MHh5  
nSplitter = nCount; R"=G?d)  
} 8%vk"h:u:  
} JF24~Q4P  
J|,| *t  
yBs  
/* Il*wVNrZI  
**Utility.java VGq2ITg9eE  
*/ |CStw"Fog  
package NetFox; !{r Gt`y  
B5J=q("P  
Ler9~}\D  
public class Utility { sE-"TNONZ  
jc)D*Cf  
pA1Tod  
public Utility() *8X: fq  
{ :N%]<Mq  
o5. q  
<=^YIp  
} Jw"'ZW#W  
"sL#)<%  
//线程睡眠 J&{E  
public static void sleep(int nSecond) a2o+tR;H  
{
t6s#19g  
try{ m:X;dcq'3  
Thread.sleep(nSecond); =(.HO:#  
} T9N /;3  
catch(Exception e) pbloL3d.;+  
{ #LBZ%%v  
e.printStackTrace (); >(~;V;
 
} ? 0nbvV5v7  
} /d8PDc"  
I
9k o*f  
//日志 b_cD >A  
public static void log(String sMsg) LI"ghz=F  
{ v:s~Y  
System.err.println(sMsg); 4}fG{B
k  
} o D:
?fs]  
\BUr2]  
L[Tr"BW  
public static void log(int sMsg) ]?b#~  
{ n#bC,  
System.err.println(sMsg); M(I 2M  
} g2w0#-  
} b@z/6y!  
hPD2/M  
dhsQfWg#}  
/* }3=]1jH6  
**TestMethod.java ),dXaP[  
*/ R279=sO,J  
package NetFox; d,+d8X  
>g8Tl`P,iN  
VmV/~-<Z  
public class TestMethod { !W .ooy5(  
m~#98ZJ^  
NR^z!+oSR  
public TestMethod() T+N%KRl  
{ ///xx/weblogic60b2_win.exe V 7%rKK  
try{ ([tbFI}A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); v#nYH?+~mJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !NjC+ps]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (A/V(.!  
fileFetch.start(); 4^ $  
} 56d,Sk)  
catch(Exception e){e.printStackTrace ();} N1+%[Uh9)  
9.D'!  
YYZE-{ %  
} cZ%weQa#N)  
IGOqV>;  
%j{gZ
Tz-  
public static void main(String[] args) Rco#?'  
{ .KXpB7:  
new TestMethod(); jrZM  
} IbF[nQ  
} `=vL?w^QS  
点击下载更多相关资料