http断点续传简单实现（java)

/* 4*L_)z&4;  
**SiteFileFetch.java (Z*!#}z`  
*/ H\ %7%  
package NetFox; 6863xOv{T  
import java.io.*; 1oS/`)  
import java.net.*; R-:2HRaA  
?[AD=rUC  
0sqFF[i  
public class SiteFileFetch extends Thread { >z03{=sAN  
E./2jCwI(Y  
:/#rZPPF  
SiteInfoBean siteInfoBean = null; //文件信息Bean > I?IPQB  
long[] nStartPos; //开始位置 8}[).d160  
long[] nEndPos; //结束位置 XX@ZQcN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _#niyW+?~  
long nFileLength; //文件长度 0f/<7R  
boolean bFirst = true; //是否第一次取文件 \Ri
P  
boolean bStop = false; //停止标志 ixFi{_  
File tmpFile; //文件下载的临时信息 +0&/g&a\R  
DataOutputStream output; //输出到文件的输出流 w(/S?d  
}6#  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） YVU7wW,1  
public SiteFileFetch(SiteInfoBean bean) throws IOException f 2.HF@  
{ 3<!7>]A  
siteInfoBean = bean; R5D1
w+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));  Sf'CN8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  DrR@n~  
if(tmpFile.exists ()) \<' ?8ri#  
{ }pYqWTG  
bFirst = false; .3;;;K9a~]  
read_nPos(); ;'|Ey  
} Wc#24:OKe3  
else | (93gJ  
{ khe}*y  
nStartPos = new long[bean.getNSplitter()]; XZ7Lk)IR  
nEndPos = new long[bean.getNSplitter()];  )2.Si#  
} N['.BN  
XwmL.Gg:]7  
[~HN<>L@C  
W4S,6(  
} <YY14p  
>Ry01G]_/h  
*pq\MiD/  
public void run() !a`&O-ye  
{ N)T}P\l  
//获得文件长度 ]esC[r]PJ  
//分割文件 ^sw?gH*  
//实例FileSplitterFetch EwN}l  
//启动FileSplitterFetch线程 aOp\91  
//等待子线程返回 wT@og|M  
try{ d-qUtgqV86  
if(bFirst) b9krOe*j  
{ S'" Df5  
nFileLength = getFileSize(); 6Oq7#3]  
if(nFileLength == -1) UN
Yqft4  
{ CTb%(<r  
System.err.println("File Length is not known!"); (zk"~Ud  
} oU8q o-J1H  
else if(nFileLength == -2) s AkdMo  
{ r@V!,k#S  
System.err.println("File is not access!"); rp$'L7lrX  
} kmW4:EA%  
else Y4-t7UlS;  
{ V88p;K$+  
for(int i=0;i<nStartPos.length;i++) vaLSH xi  
{ *w&e\i|7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;uJMG  
} 7! Nsm  
for(int i=0;i<nEndPos.length-1;i++) It(_v  
{ #"!<W0  
nEndPos = nStartPos[i+1]; TH;
hO).u  
} TOt dUO  
nEndPos[nEndPos.length-1] = nFileLength; & 21%zPm  
} By|4m  
} .Mbz3;i0  
?< +WG/(d  
@{Q4^'K"  
//启动子线程 S[gx{Bxiw  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7#XzrT]  
for(int i=0;i<nStartPos.length;i++) qGo.WZ$  
{ IxU/?Zm  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0B2t"(&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4x34u}l  
nStartPos,nEndPos,i); %J(:ADu]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I9Xuok!0>=  
fileSplitterFetch.start(); ye&;(30Oq  
} 9*gZ-#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jA1+x:Wq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -n 1v3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", P:c w|Q  
nEndPos = " + nFileLength); M3\AY30L  
// fileSplitterFetch[nPos.length-1].start(); 54T`OE =  
/m1\iM\  
(QEG4&9  
//等待子线程结束 /v{I  
//int count = 0; @gblW*Zhk  
//是否结束while循环 4(+PD&_J  
boolean breakWhile = false; %b$>qW\*&  
)A6<c%d =x  
(`^1Y3&2  
while(!bStop) 04ui`-c(  
{ }2jn[${ pr  
write_nPos(); @d'j zs  
Utility.sleep(500); e'~3oqSvR  
breakWhile = true; Q,g\  
E GU2fA7x  
ytImB`'\  
for(int i=0;i<nStartPos.length;i++) (PLUF
T  
{ ?<!|  
if(!fileSplitterFetch.bDownOver) oH@78D0A  
{ Nn6%9PX_)  
breakWhile = false; 6k%f  
break; e~OpofJNb  
} 2y4bwi  
} *dQSw)R  
if(breakWhile) 5pX6t  
break; 6nn*]|7  
itz,mrP  
("KF'fp&M2  
//count++; =_CzH(=f#  
//if(count>4) "oyo#-5z  
// siteStop();  wwqEl(  
} Wtnfa{gP%  
F?0Ykjh3  
OUnA;_  
System.err.println("文件下载结束！"); pa+hL,w{6  
} :
O
T&  
catch(Exception e){e.printStackTrace ();} M\j.8jG  
} _ q"Gix  
c<~H(k'+c  
6tZI["\   
//获得文件长度 zLQx%Yg!  
public long getFileSize() }MySaL>  
{ >*bvw~y,  
int nFileLength = -1; l
1I#QB@5n  
try{ WJi]t93  
URL url = new URL(siteInfoBean.getSSiteURL()); +A+)=/i;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UKGPtKE<  
httpConnection.setRequestProperty("User-Agent","NetFox"); K/$KI7P  
q.vIc ?a  
CpN>p.kM  
int responseCode=httpConnection.getResponseCode(); Wwo0%<2y  
if(responseCode>=400) e-;}3
66}  
{ JF]JOI6.e  
processErrorCode(responseCode); WH\d| 1)  
return -2; //-2 represent access is error l/D} X  
} ;uW FHc5@B  
ib m4fa  
(
7Qo
 
String sHeader; hH.G#-JO  
Jm@oDME_E  
4H/OBR  
for(int i=1;;i++) SbZ6t$"  
{ [g,}gyeS(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \V:^h[ad  
//Utility.log(in.readLine()); *8q.YuZ  
sHeader=httpConnection.getHeaderFieldKey(i); +ZYn? #IQ  
if(sHeader!=null) !D6]J
PX  
{ qs6aB0ln  
if(sHeader.equals("Content-Length")) 3|7QUld  
{ %<5'=t'|-U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |Tw~@kT@  
break; AA_%<zK  
} 7)m9"InDI  
} 1C.VnzRnJ  
else :UdF  
break; }Z>)DN=+  
} `oJ [u:b  
} 2%1hdA<  
catch(IOException e){e.printStackTrace ();} pAEx#ck  
catch(Exception e){e.printStackTrace ();} ~[: 2I  
t^HRgY'NjM  
s2?&!  
Utility.log(nFileLength); L];b<*d  
Ac6=(B  
%y@AA>x!  
return nFileLength; ysN3  
} 2c}E(8e]  
9uY'E'm*  
<3iMRe  
//保存下载信息（文件指针位置） 0(Ij%Wi,  
private void write_nPos() $'TM0Yu,  
{ 49P4b<1  
try{ ^.tg7%dJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z#N@ 0R  
output.writeInt(nStartPos.length); 3T 9j@N77  
for(int i=0;i<nStartPos.length;i++) ^8tEach  
{ C~[,z.FvO  
// output.writeLong(nPos); lr?;*f^3  
output.writeLong(fileSplitterFetch.nStartPos); SuznN L=/$  
output.writeLong(fileSplitterFetch.nEndPos); Cw%{G'O  
} c,22*.V/  
output.close(); zi:BF60]=  
}
0V]s:S  
catch(IOException e){e.printStackTrace ();} l%ZhA=TKQ  
catch(Exception e){e.printStackTrace ();}
mmsPLv6  
} o K@"f9  
VL^EHb7  
d _ e WcI  
//读取保存的下载信息（文件指针位置） Q\)F;:|  
private void read_nPos() p<2,=*2  
{ *"kM{*3:v  
try{ BY*Q_Et  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >p/`;Kq@  
int nCount = input.readInt(); 51u0]Qx;fm  
nStartPos = new long[nCount]; +"(jjxJm  
nEndPos = new long[nCount]; !BI;C(,RL  
for(int i=0;i<nStartPos.length;i++) #g=XUZ/"  
{ V]N?6\Op  
nStartPos = input.readLong(); Qd6FH2Pl  
nEndPos = input.readLong(); *VeRVaBl  
} 5;S.H#YOpO  
input.close(); p'fYULYE  
} {$r[5%L\H  
catch(IOException e){e.printStackTrace ();} 5IN(|B0  
catch(Exception e){e.printStackTrace ();} F?cK-.  
} }Lv;

!  
9l,oP?  
n(Uyz`qE  
private void processErrorCode(int nErrorCode) :4s1CC+@\  
{ _
U0f=m  
System.err.println("Error Code : " + nErrorCode); 1}37Q&2  
} >+waX"e  
cAy3^{3:  
_6Ha  
//停止文件下载 9kojLqCT  
public void siteStop() 7KPwQ?SjT  
{ 3F0 N^)@
 
bStop = true; V1?]|HTQcT  
for(int i=0;i<nStartPos.length;i++) kLY^!  
fileSplitterFetch.splitterStop(); C7vxw-o|&p  
!c-*O<Y  
fV:83|eQ  
} .o8t+X'G  
} X|[`P<'N<  
//负责部分文件的抓取 Y~Ifj,\  
**FileSplitterFetch.java IAEAhqp  
*/ 4=.so~9odX  
package NetFox; ^&)|sP  
b2]Kx&
!  
jIF |P-  
import java.io.*; Bf:Q2slqI  
import java.net.*; {U1m.30n  
XM}hUJJW  
l]cFqLp  
public class FileSplitterFetch extends Thread { to\Ni~a&  

TKjFp%  
 9akH  
String sURL; //File URL o.\oA6P_  
long nStartPos; //File Snippet Start Position !wp3!bLp  
long nEndPos; //File Snippet End Position <1pEwI~  
int nThreadID; //Thread's ID }i2V.tVB-  
boolean bDownOver = false; //Downing is over E e]-qN*8  
boolean bStop = false; //Stop identical 5?L<N:;J_  
FileAccessI fileAccessI = null; //File Access interface KU;9}!#  
d1kJRJ   
xCKRxF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0g\(+Qg^  
{ WKU=.sY  
this.sURL = sURL; SB7c.H,  
this.nStartPos = nStart; >Se,;cB'/]  
this.nEndPos = nEnd; [:V$y1  
nThreadID = id; %UM *79  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _~pbqa,  
} 5PW^j\G-f  
2-b6gc7  
=mGez )T5\  
public void run() MW{8VH6+  
{ T>GM%^h,7-  
while(nStartPos < nEndPos && !bStop) o14cwb  
{ 4OX^(  
oRzi>rr  
$SE^S  
try{ 'RRE|L,  
URL url = new URL(sURL);  }75e:w[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JCaOK2XT;  
httpConnection.setRequestProperty("User-Agent","NetFox");
W%)Y#C  
String sProperty = "bytes="+nStartPos+"-"; C-[1iW'  
httpConnection.setRequestProperty("RANGE",sProperty); tl].r|yl  
Utility.log(sProperty); 3,=6@U  
$g7<Y*t[  
!a<ng&H^U  
InputStream input = httpConnection.getInputStream(); +M
LVbK  
//logResponseHead(httpConnection); &=Wlaa/,&  
KdlQ!5(?X  
$kKjgQS(  
byte[] b = new byte[1024];
eY\yE"3  
int nRead; f9;(C4+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1QJL .  
{ BUR*n;V`  
nStartPos += fileAccessI.write(b,0,nRead); =ruao'A  
//if(nThreadID == 1)
9C\Fq-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iIogx8[  
} "vslZ`RU  
Q|L~=9
 
%#}Zy   
Utility.log("Thread " + nThreadID + " is over!"); qv"$Bd:]r  
bDownOver = true; rD>f|kA?L  
//nPos = fileAccessI.write (b,0,nRead); B]$GSEB  
} <|\Lm20G]  
catch(Exception e){e.printStackTrace ();} L:
8q8i  
} IMfqiH)  
} )/EO&F  
N36_C;K-z  
x=jK:3BF  
//打印回应的头信息 ;'Nd~:-]  
public void logResponseHead(HttpURLConnection con) QwJyY{O`  
{ d M-%{  
for(int i=1;;i++) z~Q>V]a>;  
{ 
4{l,  
String header=con.getHeaderFieldKey(i); 3t6LT  
if(header!=null) 9I/N4sou  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w\brVnt  
Utility.log(header+" : "+con.getHeaderField(header)); t_suF$  
else hG:|9Sol,  
break; j w9b)  
} \j)E5b+  
} I9Fr5p-%O  
$j?1g#  
~!3r&(  
public void splitterStop() PzR[KUK  
{ PY0j9$i?  
bStop = true; o+9j?|M  
} xRsWI!d+|  
6u}</>}  
r)6M!_]AW  
} Z`BK/:vo3H  
- CWywuD  
Ib0ZjX6  
/* nJLFfXWx  
**FileAccess.java 8Bg;Kh6B  
*//文件访问(定位，写) \r>6`-cs]  
package NetFox; Fr$5RAyg  
import java.io.*; 2wgg7[tGi  
pU7lnS[  
tdaL/rRe  
public class FileAccessI implements Serializable{ Lu0x (/  
F*K_+ ?m  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  _\HQvH  
RandomAccessFile oSavedFile; 'XBFv9&  
long nPos; 7`hP?a=  
=6#Eh=7N  
IyPnp&_  
public FileAccessI() throws IOException 2,P^n4~A?w  
{ -7(@1@1  
this("",0); I,'
k>@w{s  
} hDq`Z$_+KX  
0nD/;\OU  
tlt*fH$.  
public FileAccessI(String sName,long nPos) throws IOException o7LuKRl   
{ o\)F}j&b#=  
oSavedFile = new RandomAccessFile(sName,"rw"); 9 5RBO4w%w  
this.nPos = nPos; f0aKlhEC  
oSavedFile.seek(nPos); gOOPe5+ J  
} Vl!6W@g  
.@Dxp]/B}  
0k(a VkZ I  
public synchronized int write(byte[] b,int nStart,int nLen) 19KQlMO.G  
{ 9]wN Bd  
int n = -1; m7>JJX3=<  
try{
[\b0Lem  
oSavedFile.write(b,nStart,nLen); 8&Y^""#e)  
n = nLen; aCLqk'  
} Nl(3Xqov  
catch(IOException e) fe#\TNeQJ[  
{ D+7Rz_=  
e.printStackTrace (); q=qcm`ce  
} Mzw X>3x  
H?y,ie#u  
*``JamnSO  
return n; CoAvSw  
} Km6YP!i  
.Twk {p  
R#8L\1l  
} Y]u+\y~  
[bNx^VP*  
bB;5s`-  
/* 3K/MvNI>  
**SiteInfoBean.java ^_5r<{7/ :  
*/ gH3vk $WS  
package NetFox; {LQ#y/H?  
@<]Ekkg  
h@WhNk7"xa  
public class SiteInfoBean { ?r+-  
{Z5nGG  
'W,jMju  
private String sSiteURL; //Site's URL 1&(V  
private String sFilePath; //Saved File's Path ;x1PS  
private String sFileName; //Saved File's Name ~B(4qK1G  
private int nSplitter; //Count of Splited Downloading File f_Av3  
X=8{$:  
M b1sF  
public SiteInfoBean() WPG(@zD  
{//nSplitter的缺省值为5 ;Nj7qt  
//default value of nSplitter is 5 xZF}D/S?Ov  
this("","","",5); @Sbe^x  
} *lw_=MXSK  
KX7>^Bt&k  
6,9>g0y'NG  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;<2G  
{ 4G>H  
sSiteURL= sURL; U,-39mr  
sFilePath = sPath; ?r2` Q  
sFileName = sName; LRG6
:&  
this.nSplitter = nSpiltter; &wE%<"aRAl  
o\pVpbB  
TNh1hhJ$b  
} #PQB(=299P  
BC<^a )D=  
K8.!_ c  
public String getSSiteURL() :#?5X|Gz  
{ dg"3rs /?A  
return sSiteURL; J9iy  
} X;c'[q  
tX %5BTv  
!pdb'*,n  
public void setSSiteURL(String value) KOuCHqCfq  
{ p\ZNy\N^  
sSiteURL = value; s;vHPUB\n  
} vf%&4\ib  
I4q9|'-yx  
,lA  s
 
public String getSFilePath() 6@0OQb  
{ Fv<F}h?6  
return sFilePath; .KUv(-  
} 6WJ)by  
"Yj'oE%\  
aAMVsE{  
public void setSFilePath(String value) ApV~(k)W  
{ ~C`^6UQr/?  
sFilePath = value; 4'A!; ]:  
} 2=`o
_<P'"  
04l!:Tp,  
*P2S6z2  
public String getSFileName() ],a5)kV  
{ B%76rEpvW;  
return sFileName; emPM4iG?!  
} B1C-J/J  
(/j/>9iro  
O7<]U_"I  
public void setSFileName(String value) .1Al<OLL  
{ [t@Mn  
sFileName = value; &wCg\j_c  
} L(-b@Joh  
_JE"{ ;  
b@f$nS B  
public int getNSplitter() '*w00  
{ k$J zH$  
return nSplitter; [knN:{ l  
} r^paD2&}  
'JfdV%M  
o`P%&  
public void setNSplitter(int nCount) $79=lEn,  
{ k!HK 97qA  
nSplitter = nCount; A}N?/{y)G  
} `_RTw5{  
} R:k5QD9/&p  
_p&]|~a  
1Y@Aixx  
/* \uC15s<  
**Utility.java 48qV>Gwf  
*/ ,\ k(x>oy  
package NetFox; 5$&%re!{Z  
Id|L` w  
fM63+9I)\  
public class Utility { G) 7;;  
ahOMCZF|  
\LppYXz  
public Utility() <|+Ex  
{ TDNQu
_E  
|J}Mgb-4  
J/GSceHF  
} $[&*Bj11Yg  
G<f@#[$'  
//线程睡眠 af+IP_6 .  
public static void sleep(int nSecond) vbB
c}G"w  
{ FCuB\Q  
try{ \r,Q1n?7  
Thread.sleep(nSecond); Rh{zH~oZ  
} +W\f(/q0  
catch(Exception e) Vle@4]M\  
{ s
q[iY  
e.printStackTrace (); x`mN U  
} WKIoS"?-F  
} tj4VWJK  
{(wHPzq  
//日志 ac.Ms(D  
public static void log(String sMsg) ^!
z[t\$  
{ !l 1fIc  
System.err.println(sMsg); F\k+[`%{  
} \\7ZWp\fN  
YmgLzGk`  
?5cI'  
public static void log(int sMsg) mvZw  
{ ,7NZu0  
System.err.println(sMsg); >U*T0FL7  
} ?1$fJ3  
} $UCAhG$  
\lC   
oMTf"0EIW  
/* JJ'.((  
**TestMethod.java *B{j.{ p(  
*/ [E JQ>?D  
package NetFox; Jesjtcy<*  

,o,I5>`  
ICkp$u^  
public class TestMethod { 0B@Jity#!  
Qj6/[mUr~  
p2udm!)J  
public TestMethod() y+6o{`0  
{ ///xx/weblogic60b2_win.exe pg%aI,  
try{ )>-ibf`#?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); K7Wk6Aw  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); G\r?f&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H& Ca
`B  
fileFetch.start(); .0O2Qqdg  
} 3*)ig@e6  
catch(Exception e){e.printStackTrace ();}  S"$m]  
yH*6@P4:0=  
Zrr5csE  
} !M]\I&  
sZm$|T0  
,NVsn  
public static void main(String[] args) e `,ds~  
{
F^LZeF[#t  
new TestMethod(); FMkzrs  
} c#]q^L\x  
} *9c!^$V  
点击下载更多相关资料