http断点续传简单实现（java)

/* iB)\*)  
**SiteFileFetch.java <
=.6Z*x+  
*/ V4,Gt]4  
package NetFox; rfwJLl/  
import java.io.*; )\1>)BJq  
import java.net.*; ~B;}jI]d[  
PuNL%D  
X:W\EeH  
public class SiteFileFetch extends Thread { ;J W]b]  
Hu|Tj<S  
vb>F)X?b_  
SiteInfoBean siteInfoBean = null; //文件信息Bean Ae>+Fcv  
long[] nStartPos; //开始位置 poQ_r<I  
long[] nEndPos; //结束位置 ^#R`Upt
ib  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +f/ I>9G  
long nFileLength; //文件长度 b}qfOgd5  
boolean bFirst = true; //是否第一次取文件 =8]`-(  
boolean bStop = false; //停止标志 rH7Cv/Y  
File tmpFile; //文件下载的临时信息 v'hc-Q9+>  
DataOutputStream output; //输出到文件的输出流 fpf]qQ W~7  
wpZ"B+oK!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /|v4]t-  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5;)^o3X>  
{
UT3Fi@  
siteInfoBean = bean; 8eB,$;i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :rb;*nY!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }g+kU1y  
if(tmpFile.exists ()) mF 1f(  
{ 9k6s  
bFirst = false; cO5F=ZxR  
read_nPos(); HyzSHI  
} \TP$2i%W  
else Q:P)g#suc  
{ tD.#*.7  
nStartPos = new long[bean.getNSplitter()]; QM(xMq  
nEndPos = new long[bean.getNSplitter()]; 38w^="-T  
} }d.X2?  
YoKE=ln7  
#L.,aTA<  
m"!SyN}&9?  
} d|R-K7 ~~  
f/Y&)#g>k  
3q%z
 
public void run() =`+D/ W\[Y  
{ yr%[IX]R  
//获得文件长度 ?M:>2wl  
//分割文件 eA& #33  
//实例FileSplitterFetch 9^/Y7Wp/@  
//启动FileSplitterFetch线程 `KZV@t  
//等待子线程返回 N:lE{IvRJ  
try{ _$UJ'W})/  
if(bFirst) *}]#E$  
{ O:0{vu9AQ  
nFileLength = getFileSize(); bSe\d~{  
if(nFileLength == -1) w+6P x#  
{ !.UE}^TV  
System.err.println("File Length is not known!"); $`lWW6>P  
} W`x.qumN
 
else if(nFileLength == -2) qm_l# u6  
{ rO#w(]   
System.err.println("File is not access!"); cX9o'e:C  
} Tx}Nr^  
else JMB#KzvN[  
{ 6xDk3  
for(int i=0;i<nStartPos.length;i++) 1'f_C<.0  
{ 336ETrG^0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); T`e`nQ0nn  
} 9n(68|^$  
for(int i=0;i<nEndPos.length-1;i++) |3~m8v2-  
{ RG'iWA,9m`  
nEndPos = nStartPos[i+1]; &5y  
} Pg}QRCB@  
nEndPos[nEndPos.length-1] = nFileLength; 1o&zA<+NY  
} xN*k&!1&  
} LcGKYl(\K  
I0x)d`  
4$iS@o|  
//启动子线程 (xG%H:6,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; cvsH-uAp  
for(int i=0;i<nStartPos.length;i++) -*7i:mg  
{ VJ\qp%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Fv]6an.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), uzHMQp  
nStartPos,nEndPos,i); o}Grb/LJ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8y27O  
fileSplitterFetch.start(); 'xta/@Sq  
} S TWH2_`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kl]
V_ 7[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vb^fx$V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rN9qH  
nEndPos = " + nFileLength); ,\i*vJ#f  
// fileSplitterFetch[nPos.length-1].start(); X$UK;O  
E_~e/y"-  
CT'4.  
//等待子线程结束 XYvj3+  
//int count = 0; anSZWQ  
//是否结束while循环 _
_b4
dv  
boolean breakWhile = false; 6rnFXZ\  
Md4Q.8  
GTLS0l)  
while(!bStop) '1D$ ;  
{ 1 3]e< '  
write_nPos(); -+[Lc_oNPx  
Utility.sleep(500); X|\`\[  
breakWhile = true; 6CFnE7TQf  
nFJW\B&(`  
;t*SG*Vi  
for(int i=0;i<nStartPos.length;i++)  +rv##Z  
{ }<~(9_+  
if(!fileSplitterFetch.bDownOver) LF7 }gQs ^  
{ l :{q I#Q  
breakWhile = false; :m`D  
break; x1Gx9z9  
} 2OUx@Vj  
} dm}1"BU<  
if(breakWhile) lW5Lwyt8  
break; {

> ,M  
sl-wNIQ  
]r#b:W\  
//count++; $,K@xq5  
//if(count>4) rG?5z"  
// siteStop(); q;#AlquY@  
} I8! .n  
GZi`jp  
?lkB{-%rQ  
System.err.println("文件下载结束！"); @2T8H  
} }vh <x6  
catch(Exception e){e.printStackTrace ();} `V9bd}M%~;  
} H<|}pZ  
S"*k
#ao  
j1`<+YT<#  
//获得文件长度 `^Ll@Cx"  
public long getFileSize() %l8!p'a  
{ LBq
2({="  
int nFileLength = -1; ^oav-R&  
try{ z00X ?F  
URL url = new URL(siteInfoBean.getSSiteURL()); <cOjtq,0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VHPqEaR  
httpConnection.setRequestProperty("User-Agent","NetFox"); eGT&&Y  
}>M\iPO.]*  
^1~lnD~0  
int responseCode=httpConnection.getResponseCode(); Z-lhJ<0/Pa  
if(responseCode>=400) kcUn GiP  
{ k.b=EX|  
processErrorCode(responseCode); %~:\f#6  
return -2; //-2 represent access is error LCSvw  
} WyOav6/*K^  
1n<4yfJ  
8o+:|V~X  
String sHeader; 7HVENj_b+M  
8?8V; 
 
0S:&wb  
for(int i=1;;i++) ,y'6vW`%g9  
{ aAe`o2Xs  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L~f~XgQ  
//Utility.log(in.readLine()); Dl.UbH }=  
sHeader=httpConnection.getHeaderFieldKey(i); $
(gL#"T  
if(sHeader!=null) 7zx xO|p[  
{ d`TiY`!  
if(sHeader.equals("Content-Length")) P>rRD`Yy\  
{ g^H,EaPl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); qqo#H O  
break; l$1?@l$j  
} A{4,ih"5  
} }j2;B 8j  
else lusUmFm'*  
break; Pk;/4jt4  
} |J4sQ!%K  
} g4k3~,=D3  
catch(IOException e){e.printStackTrace ();} V'#R1x"3  
catch(Exception e){e.printStackTrace ();} 7k,BE2]"  
q)9n%- YgP  
%\HE1d5;  
Utility.log(nFileLength); fZpi+I  
^[.}DNR95(  
Q>Klkd5(  
return nFileLength; .`~?w+ ~  
} tl /i  
{St-
 
YvN]7tcb  
//保存下载信息（文件指针位置） 'k]~Q{K$  
private void write_nPos() 0?oL zw&  
{ p*5_+u  
try{ ;=$;h6W0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); st
* sv}  
output.writeInt(nStartPos.length); !&Q?ASJH  
for(int i=0;i<nStartPos.length;i++) iS)-25M'  
{ s<"|'~<n  
// output.writeLong(nPos); i`e[Vwe2x@  
output.writeLong(fileSplitterFetch.nStartPos); kh#QT_y  
output.writeLong(fileSplitterFetch.nEndPos); iJE:>qOTD5  
} { i6L/U.  
output.close(); uvJHkAi  
} tz2=l.1  
catch(IOException e){e.printStackTrace ();} 7omHorU+  
catch(Exception e){e.printStackTrace ();} ]QHp?Ii1  
} [uGsF0#e  
hFm^Fy[R  
~C^:SND7  
//读取保存的下载信息（文件指针位置） )bih>>H  
private void read_nPos() qD*y60~]zz  
{ /0qbRk i  
try{ YFS6YA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0
ZwXuq  
int nCount = input.readInt(); k L6s49  
nStartPos = new long[nCount]; , @UO
j=  
nEndPos = new long[nCount]; +kd1q  
for(int i=0;i<nStartPos.length;i++) I;"pPJ3G  
{ Nc(CGl:
 
nStartPos = input.readLong(); mST8+R@S  
nEndPos = input.readLong(); C{m%]jKH  
} [u!n=ev  
input.close(); vE^tdzAG  
} Cp/f18zO  
catch(IOException e){e.printStackTrace ();} XQn1B3k+  
catch(Exception e){e.printStackTrace ();} N,K/Ya)1  
} J;Z2<x/H  
O<Q8%Az  
g(tVghHxt$  
private void processErrorCode(int nErrorCode) M1WD^?tKQ.  
{ dq.U#Rhrx  
System.err.println("Error Code : " + nErrorCode); .B<Bqr@?8  
} Lfi6b%/z  
.Ja].hP  
~Z
/,o)  
//停止文件下载 X-nC2[tu'W  
public void siteStop() mj$Ucql  
{ X uE: dL?  
bStop = true; 1|4,jm$  
for(int i=0;i<nStartPos.length;i++) 3%5
YUG@  
fileSplitterFetch.splitterStop(); (eU4{X7  
xE@/8
h  
P#!
N  
} gZ^Qt.6Z  
} h_#=
f(.'j  
//负责部分文件的抓取 u#EcR}=]  
**FileSplitterFetch.java aR6F%7gvz  
*/ ^D+^~>f  
package NetFox; ,.0bE 9\o  
7Q&-ObW  
h-1?c\Qq:  
import java.io.*; =3(Auchl$Y  
import java.net.*; ou-UR

5  
I[k"I(  
:!g|pd[{ag  
public class FileSplitterFetch extends Thread { 1Zn8CmE V  
R`c[?U  
DNq(\@x[!  
String sURL; //File URL ko[w#j  
long nStartPos; //File Snippet Start Position u*Xp%vNe  
long nEndPos; //File Snippet End Position e^\e;>Dh>  
int nThreadID; //Thread's ID Gqd|F>  
boolean bDownOver = false; //Downing is over (&eF E
;c  
boolean bStop = false; //Stop identical \t=0rFV)t  
FileAccessI fileAccessI = null; //File Access interface Godrz*"  
:sg}e  
gm)Uyr$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _

xv3UzD  
{ YS^!'IyG/B  
this.sURL = sURL; O_1[KiZ  
this.nStartPos = nStart; X8ap   
this.nEndPos = nEnd; z5$Q"Y.D  
nThreadID = id; A`Dx]y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :CE4< {V  
} KL=<s#
 
U&WEe`XM  
0pMN@Cz6  
public void run() '+_>PBOc  
{ K2M=)B  
while(nStartPos < nEndPos && !bStop) =D$ED^W  
{ %a~/q0o>  
|~BnE  
{7goYzQsi%  
try{ @p*)^D6E\  
URL url = new URL(sURL); u5A?; a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oV:oc,  
httpConnection.setRequestProperty("User-Agent","NetFox"); D;C';O  
String sProperty = "bytes="+nStartPos+"-"; XJe=+_K9  
httpConnection.setRequestProperty("RANGE",sProperty); DO80HS3ZD  
Utility.log(sProperty); =|agW.l  
`?Q p>t  
(|^m9v0:  
InputStream input = httpConnection.getInputStream(); b&F9<XLqq  
//logResponseHead(httpConnection); _aPAn
|.  
=lJ ?yuc  
/jGBQ-X  
byte[] b = new byte[1024]; 0h@FHw2d  
int nRead; WSHPhhM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) nf /*n  
{ p?Azn>qBa  
nStartPos += fileAccessI.write(b,0,nRead); lNL=Yu2p_  
//if(nThreadID == 1) EB*sd S  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2; ^ME\  
} 2HFn\kjj.s  
1'<C-[1  
Bx#i?=*W  
Utility.log("Thread " + nThreadID + " is over!"); .}!.4J%q2  
bDownOver = true; 7
_i8'(``  
//nPos = fileAccessI.write (b,0,nRead); RHC ZP  
} mF*x&^ie  
catch(Exception e){e.printStackTrace ();} ~+dps i  
} GjhTF|  
} !CYC7HeF  
0MHiW=  
Ax=HDW}  
//打印回应的头信息 >lRZvf-i  
public void logResponseHead(HttpURLConnection con) Eu?z!  
{ X@`a_XAfd  
for(int i=1;;i++) (P)G|2=  
{ Q|AZv>'!  
String header=con.getHeaderFieldKey(i); 27eG8  
if(header!=null) g5B TZZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); SQ>i:D;  
Utility.log(header+" : "+con.getHeaderField(header)); SL4?E<J
b  
else qG6s.TcG  
break; sP(+Z^/  
} 5M
l=<^  
} '}_r/l]K  
Z0Z6aZeb  
Xi&J%N'  
public void splitterStop() W*
C~Xba<  
{ I$7eiW @  
bStop = true; +& r!%j7  
} OjUPvR2 0  
{zFME41>g  
p u(mHB  
} F^O83[S  
~29p|X<  
!&VfOx:PN  
/* 8?+|4:#=*J  
**FileAccess.java ]Btkoad  
*//文件访问(定位，写) *HKw;I   
package NetFox; >aVgI<   
import java.io.*; ]b4IO4T  
7QsD"rL  
"313eeIt%i  
public class FileAccessI implements Serializable{ GI%&.Vd  
F_ F"3'[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 cszvt2BIg  
RandomAccessFile oSavedFile; sAkr-x?+M  
long nPos; J$3g3%t  
@ma(py  
\Rny*px  
public FileAccessI() throws IOException (&:gD4.  
{ dVQ[@u1,  
this("",0); 79h~w{IT@  
} e,U:H~+]  
]Ox5F@  
BR2Gb~#T  
public FileAccessI(String sName,long nPos) throws IOException eTuqK23  
{ zK<af  
oSavedFile = new RandomAccessFile(sName,"rw"); g":[rXvId  
this.nPos = nPos; R+M&\5  
oSavedFile.seek(nPos); T D_@0Rd  
} z:,PwLU  
eM5?fE&!&  
Zzlf1#26\  
public synchronized int write(byte[] b,int nStart,int nLen) ~ nsb  
{ 4V,.Oi  
int n = -1; gF)9a_R%p  
try{ "%-Vrb=:Y  
oSavedFile.write(b,nStart,nLen); wX,V:QE  
n = nLen; <g[z jV9p  
} {OU|'  
catch(IOException e) {a7~P0$  
{ xe`^)2z  
e.printStackTrace (); |mb2<!ag{  
} 7j]v_2S`  
~e{ @5
.g  
1 R5pf  
return n; `%C-7D'?  
} j_Szw w-  
NQ9v[gv  
AcH-TIgM/  
} H9cPtP~a)  
@]=40Yj~w  
<)VgGjZ-H  
/* V ;T :Q%  
**SiteInfoBean.java A6&*VD  
*/ d#ir=+o{h  
package NetFox; !J`lA  
gYKz,$  
2B,O
/3y  
public class SiteInfoBean { Ed9Uw7  

D|;O9iks#  
*%j$i_  
private String sSiteURL; //Site's URL Y=Vbs x  
private String sFilePath; //Saved File's Path .G0 N+)  
private String sFileName; //Saved File's Name Luq4q95]  
private int nSplitter; //Count of Splited Downloading File a{5SOe;;  
#z `W ,^C  
,erw(7}'.  
public SiteInfoBean() @A/k"Ax{r  
{//nSplitter的缺省值为5 1vj/6L  
//default value of nSplitter is 5  F!omkN  
this("","","",5); `9~ %6N?7#  
} ,WT>"9+  
3N7H7(IR  
)g0fN+Mb  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {0zn~+  
{ M;(,0dk  
sSiteURL= sURL; Yd^@Ei9
 
sFilePath = sPath; G=zWhqieh  
sFileName = sName; Z~5) )5Ye;  
this.nSplitter = nSpiltter; hx;f/EPx  
Or
Y[  
G95,J/w  
} {Mx(|)WkL  
8K 3dwoT  
M([#Py9h  
public String getSSiteURL() (Fv tL*  
{ xs$$fPAQ  
return sSiteURL; n<I{x^!  
} rwm^{Qa  
IPiV_c-l  
cnv>&6a)  
public void setSSiteURL(String value) ZO0 Ee1/  
{ $XBK_ 5  
sSiteURL = value; KpLmpK1  
} U.%Kt,qB  
qNp1<QO0  
xP;r3u s  
public String getSFilePath() WjV15\,  
{ K2   
return sFilePath; ]MbPivM  
} I=Y>z^4  
_X6'uJ  
&p0e)o~Ux  
public void setSFilePath(String value) &d#R'Z  
{ 8.E"[QktZ  
sFilePath = value; qe~x?FO_>  
} wp[Ug2;G  
$pGT1oF
[E  
f:T?oR>2  
public String getSFileName() :2 ;Jo^6Se  
{ KyvZ?R  
return sFileName; sp9gz~Kq
 
} J=4>zQ
LW  
PNU(;&2<  
E-e(K8R  
public void setSFileName(String value) U84W(X  
{ P]E-Wp'p  
sFileName = value; 5j%G7.S\  
} 6SSDc/  
*GP2>oEM  
d[ N1zQW  
public int getNSplitter() L*nK> +  
{ /?\3%<vn  
return nSplitter; G dgL}"*F  
} FMfpjuHk  
Hvl
n>x@  
Wboh2:TH:  
public void setNSplitter(int nCount) k4TWfl^}9  
{ D:)Wr, 26  
nSplitter = nCount; I`>U#x*  
} v9$!v^U"D  
} rr<E#w  
>ZA=
9v  
bp1AN9~  
/* ab0Sx  
**Utility.java +/:tap|V  
*/ i;[y!U  
package NetFox; 1v o)]ff  
1+o]+Jz|  
I7f ^2  
public class Utility { jvT'N@  
J 3!~e+wn  
|s|}u`(@9  
public Utility() >.h:Y5  
{ ,Z.sGv  
4 1_gak;  
*O?c~UJhhV  
} tAX*CMW  
'J|2c;M\x  
//线程睡眠 B.z$0=b  
public static void sleep(int nSecond) %+7]/_JO&  
{ @KG0QHyiU  
try{ >}5?`.K~Q*  
Thread.sleep(nSecond); X/!_>@`7?  
} xad`-vw  
catch(Exception e) Jh[0xb  
{ Onmmcem  
e.printStackTrace (); 74s{b]jN'-  
} |<%!9Z  
} Cs $5Of
(  
{]vD@)k  
//日志 >1y6DC  
public static void log(String sMsg) ?ukw6T  
{ ?Ua,ba*  
System.err.println(sMsg); S_}`'Z )  
} Cj5mM[:s  
:<%bAn  
UHBXq;?&q  
public static void log(int sMsg) eH&F gmU  
{ ">A<%5F2  
System.err.println(sMsg); 5&Oc`5QD  
} 4aayMS!#  
} rk=D5E7  
^xo<$zn
 
.nV2n@SR  
/* >J"INI  
**TestMethod.java DA=!AK>  
*/ ,'#TdLe  
package NetFox; 7y=>Wa?T[  
E-LkP;  
A_9WSXR  
public class TestMethod { f~IJ4T2#N  
)7q$PcY  
3;nOm =I  
public TestMethod()
Bous d  
{ ///xx/weblogic60b2_win.exe i1iP'`
r  
try{ -@To<<`n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *4,Q9K_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _ _Of0<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =KRM`_QShg  
fileFetch.start(); TS<d?:  
} /-=fWtA  
catch(Exception e){e.printStackTrace ();} lFBdiIw  
Aq i:h]x  
+X?ErQm  
} ~ELY$G.xl  
=w2 4(S  
PK*Wu<<  
public static void main(String[] args) K+g[E<x\=  
{ X-pbSq~5  
new TestMethod(); [g}Cve#i  
} _0H oJ  
} UBvp32p  
点击下载更多相关资料