http断点续传简单实现（java)

/* VhO+nvd*W  
**SiteFileFetch.java z|pt)Xl  
*/ \5a.JfF  
package NetFox; UFj H8jSBx  
import java.io.*; )Rn\6ka  
import java.net.*; gX"-3w  
\c2x udU  
cZVx4y%kz
 
public class SiteFileFetch extends Thread { O#D{:H_dD>  
aM~IRLmK  
cKTjQJ#  
SiteInfoBean siteInfoBean = null; //文件信息Bean #Th)^Is  
long[] nStartPos; //开始位置 .i*oZ'[X  
long[] nEndPos; //结束位置 JCcYFtW  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _Q+c'q Zkl  
long nFileLength; //文件长度 8H7#[?F  
boolean bFirst = true; //是否第一次取文件 L\#YFf  
boolean bStop = false; //停止标志 >6S7#)0T  
File tmpFile; //文件下载的临时信息 eha|cAq  
DataOutputStream output; //输出到文件的输出流 +u|"q+p  
Ar<5UnT  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） NtM>`5
{?  
public SiteFileFetch(SiteInfoBean bean) throws IOException 30vxOkS
 
{ @&?(XY 'M%  
siteInfoBean = bean; }u
ma<b  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y%;J/4dd  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .Y6v#VI  
if(tmpFile.exists ()) S<7!<]F-  
{ e]VW\6J&  
bFirst = false; iqlb,8  
read_nPos(); ,#2~<  
} 3)WfBvG  
else G2|jS@L#  
{ r;{$x  
nStartPos = new long[bean.getNSplitter()]; rt^~ I\V  
nEndPos = new long[bean.getNSplitter()]; BL&AZv/T  
} ]W;6gmV  
YYpC!)  
3CD#OCz7&  
yeiIP  
} Erw1y,mF  
&dtst??  
)#i@DHt=  
public void run() \Y!#Y#c  
{ cF 5|Pf  
//获得文件长度 xf&[QG+Ef  
//分割文件 Mp/l*"(  
//实例FileSplitterFetch X,
G<D}  
//启动FileSplitterFetch线程 NK qIx  
//等待子线程返回 4s7 RB  
try{ wQG?)aaM  
if(bFirst) ,ayEZ#4.m  
{ !=eNr<:V.  
nFileLength = getFileSize(); r#OPW7mhE  
if(nFileLength == -1) .e7tq\k  
{ M{ncWq*_j  
System.err.println("File Length is not known!"); <&m50pq  
} jfG of*  
else if(nFileLength == -2) m[eqTh4*  
{ -6+7&.A+  
System.err.println("File is not access!"); P4@`C{F5m  
} (tYZq86`  
else H$Kc~#=  
{ oMN<jAU.  
for(int i=0;i<nStartPos.length;i++) v#x`
c_  
{ n~UI47  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wH?)ZL  
} yx Om=V  
for(int i=0;i<nEndPos.length-1;i++) 8xENzTR  
{ D^4nT,&8  
nEndPos = nStartPos[i+1]; Oa/zEH  
} VgVDTWs7  
nEndPos[nEndPos.length-1] = nFileLength; Qa,
=  
} TVcA%]y{;  
} E!ndXz 59  
0Fb];:a  
9)7$UQY  
//启动子线程 +%YBa'Lk  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /K|(O^nw  
for(int i=0;i<nStartPos.length;i++) @Fc:9a@  
{ US$$ADq  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @dv8 F "v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bB?E(>N;  
nStartPos,nEndPos,i); g4A{RI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e@vtJaSu  
fileSplitterFetch.start(); ]mMJ6n  
} 9:p-F+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Aax;0qGbH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <7]HM5h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", KAnV%j  
nEndPos = " + nFileLength); jh/,G5RM9  
// fileSplitterFetch[nPos.length-1].start(); ~5+RK16  
YH\9Je%jx  
~yJ2@2I  
//等待子线程结束 |OJWQU![by  
//int count = 0; (=^KP7  
//是否结束while循环 WnG2\(U  
boolean breakWhile = false; qm$(_]R~`  
$A?9U}V#^  
n1PptR  
while(!bStop) }sH[_%)  
{ 3SIqod;%  
write_nPos(); :V.@:x>id  
Utility.sleep(500); U,P>P+\@  
breakWhile = true; 4fsd5#  
'yPKQ/y$x  
9" q-Bb  
for(int i=0;i<nStartPos.length;i++) hY.i`sp*/  
{ ],SQD3~9  
if(!fileSplitterFetch.bDownOver) Ysu\CZGX  
{ CFh9@
Nx  
breakWhile = false; jh oA6I  
break; fz^j3'!\  
} I6 ?(@,  
} _f0AV;S:vd  
if(breakWhile) t}eyfflZ  
break; %]Z4b;W[Y  
K ~mUO  
aG]>{(~cL  
//count++; y2I7Zd .  
//if(count>4) 5csh8i'V  
// siteStop(); O?X[&t  
} YJv$,Z&;HO  
mi] WZlg$  
Mq$K[]F  
System.err.println("文件下载结束！"); Wu{=QjgY  
} eMRH*MyD  
catch(Exception e){e.printStackTrace ();} B`mJT*B[  
} 5(H%Ia  
upuN$4m&{  
W+&5G(z~  
//获得文件长度 d AcSG  
public long getFileSize() _H]^7`;  
{ ]"_c-=  
int nFileLength = -1; P)K$+oo  
try{
]QaKXg)3q  
URL url = new URL(siteInfoBean.getSSiteURL()); `sKyvPtG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LJ[zF~4#  
httpConnection.setRequestProperty("User-Agent","NetFox"); B)Y[~4o  
:rL%,o"  
l?*DGW(t{  
int responseCode=httpConnection.getResponseCode(); Zkd{EMW  
if(responseCode>=400) \o!3TK"N  
{ w&?XsO@0W  
processErrorCode(responseCode); nW)+-Wxq  
return -2; //-2 represent access is error FPYk`D  
} tkctwjD  
#r9+thyC  
<(KCiM=E$  
String sHeader; -iiX!@  
wGti|7Tu*  
vntJe^IaFd  
for(int i=1;;i++) &DMC\R*j  
{ S=k!8]/d|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q~]oN  
//Utility.log(in.readLine()); x1eC r_  
sHeader=httpConnection.getHeaderFieldKey(i); s-IE}I?;  
if(sHeader!=null) ts~VO`  
{ =R=V  
if(sHeader.equals("Content-Length")) 6nk}k]Ji  
{ RU~na/3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); E /H%q|q  
break; K}CgFBk  
} ,LA'^I?  
} <uuumi-!%G  
else `a&L  
break; <2
)AbI+3  
} .~o{i_JH  
} eaFkDl  
catch(IOException e){e.printStackTrace ();} 2V@5:tf  
catch(Exception e){e.printStackTrace ();} *5PQ>d G  
naaKAZ!S  
YcA. Bn|as  
Utility.log(nFileLength); %k#+nad  
s
a8O<Ab  
*/e$S[5  
return nFileLength; "\@J0|ppb  
} Ve(<s  
%f'pAc|#  
f![] :L  
//保存下载信息（文件指针位置） \>5sW8P]H`  
private void write_nPos() ;$
iT]S  
{ ytY\&m  
try{ #1%@R<`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0i\
>(o  
output.writeInt(nStartPos.length); 5}G_2<G  
for(int i=0;i<nStartPos.length;i++) BHY-fb@R]H  
{ MZ"V\6T]  
// output.writeLong(nPos); Z+k) N  
output.writeLong(fileSplitterFetch.nStartPos); hA ){>B<;  
output.writeLong(fileSplitterFetch.nEndPos); o:#jvi84F  
} MUl`0H"tR  
output.close(); B[ZQn]y  
} SPV+ O{  
catch(IOException e){e.printStackTrace ();} '^)'q\v'k  
catch(Exception e){e.printStackTrace ();} k)3N0]q6  
} qefp3&ls  
QKP #wR  
=wX;OK|U(^  
//读取保存的下载信息（文件指针位置） 9CS"s_  
private void read_nPos() *B3f ry  
{ $}(Z]z}O;  
try{ :Hq%y/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qA '^b~  
int nCount = input.readInt(); V<9L-7X 8  
nStartPos = new long[nCount]; Hpix:To  
nEndPos = new long[nCount]; +1wEoU.l2  
for(int i=0;i<nStartPos.length;i++) 1R}9k)JQ  
{ n=-vOa%  
nStartPos = input.readLong(); 1<vJuF^  
nEndPos = input.readLong(); wxHd^b  
} X.#*+k3s0
 
input.close(); cI[i v  
} fcdXj_u  
catch(IOException e){e.printStackTrace ();} WuE]pm]c  
catch(Exception e){e.printStackTrace ();} &n| <NF  
} Tp-W/YC  
,C6(  
8d*S9p,/  
private void processErrorCode(int nErrorCode) r#WqXh_uk  
{ Oey Ph9^V  
System.err.println("Error Code : " + nErrorCode); >aJmRA-C}  
} drAJ-ii  
!!L'{beF  
6|p8_[e`  
//停止文件下载 jlb8<xIC]  
public void siteStop() _i ztQ78  
{ L&+k`b
  
bStop = true; 0i}.l\  
for(int i=0;i<nStartPos.length;i++) eM!Oc$C8[  
fileSplitterFetch.splitterStop(); Ly(
iq  
0dwD ?GG2  
^JxVs 7  
} 9 5!xJdq  
} ,$!fyi[;C  
//负责部分文件的抓取 5:38}p9`
 
**FileSplitterFetch.java VJ#ys_W  
*/ s>L-0vG  
package NetFox; d1#lC*.Sg  
cWnEp';.  
;L:UYhDbUx  
import java.io.*; oTvg%bX  
import java.net.*; 5
dv|NLl  
1;m?:|6K{  
M5*Ln-qt(a  
public class FileSplitterFetch extends Thread { lFuW8G,-f@  
k@fxs]Y_L  
=,*/Ph&  
String sURL; //File URL 15_"U+O(/  
long nStartPos; //File Snippet Start Position \0lQ1FrY  
long nEndPos; //File Snippet End Position L__{U_p  
int nThreadID; //Thread's ID -5e8m4*
 
boolean bDownOver = false; //Downing is over L2Cb/!z`c  
boolean bStop = false; //Stop identical 0>m$e(Z  
FileAccessI fileAccessI = null; //File Access interface B0RVtbK  
v"2A?  
MX*4d{l  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A PSkW9H  
{ ,&,XcbJ  
this.sURL = sURL; 9/8+R%  
this.nStartPos = nStart; V9ZM4.,OCN  
this.nEndPos = nEnd; 6 [bQ'Ir^8  
nThreadID = id; i=^6nwD&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _l)3pm6  
} &iD&C>;pf  
6a9:P@tY  
,I|^d.[2  
public void run() jKcl{',  
{ Jm=3%H  
while(nStartPos < nEndPos && !bStop) @=g{4(zR^  
{ .`KzA]&#  
\|vo@E  
SIM>Lz  
try{ V,zFHX
O  
URL url = new URL(sURL); KY2z)#/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cC9Zc#aK  
httpConnection.setRequestProperty("User-Agent","NetFox"); <bJ|WS|  
String sProperty = "bytes="+nStartPos+"-"; "WY5Pzsi:  
httpConnection.setRequestProperty("RANGE",sProperty); V9KRA 1  
Utility.log(sProperty); vx$DKQK@l\  
yEB#*}K?  
E}zGY2Xx  
InputStream input = httpConnection.getInputStream(); NHU5JSlB  
//logResponseHead(httpConnection); L8E4|F}  
>`WQxkpy  
- ]/=WAOK  
byte[] b = new byte[1024]; t0<RtIh9e  
int nRead; >t9
DI  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4<<eqxI$|  
{ |pknaz  
nStartPos += fileAccessI.write(b,0,nRead); bWp)'mx5u  
//if(nThreadID == 1) M!hD`5.3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /V/)A\g  
} |U'`Sc  
xA;)02  
wk?i\vm  
Utility.log("Thread " + nThreadID + " is over!"); ',Z]w;D!G
 
bDownOver = true; Z @DDuVr  
//nPos = fileAccessI.write (b,0,nRead); 5l,Lp'k  
} Q4Wz5n1yp7  
catch(Exception e){e.printStackTrace ();} %IIFLl
D  
} ,<7HLV  
} c8zok `\P_  
1LSD,t|  
18j>x3tn  
//打印回应的头信息 lQgavP W!  
public void logResponseHead(HttpURLConnection con) W3('1  
{ 7#&Q-3\:  
for(int i=1;;i++) O<AGAD  
{ .2|(!a9W  
String header=con.getHeaderFieldKey(i); _/ 5  
if(header!=null) =yRv*C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]l=CiG4!M  
Utility.log(header+" : "+con.getHeaderField(header)); 3*?W2;Zw$  
else 00-2u~D&  
break; Wj)v,v2&  
} aU.!+e%_  
} ,1t|
QvO  
F *U.cJ%  
Y~r)WV!G  
public void splitterStop() [tC=P&<  
{ .Y!dO@$:  
bStop = true; "fN 6
_
*  
} VV[Fb9W ;  
;Ob^@OM  
0a!|*Z  
} j5smmtM`s  
#N"QTD|i  
oZL# *Z(h  
/* }Q^*Zq9-  
**FileAccess.java [_
KOU2  
*//文件访问(定位，写) C0^r]^$Z  
package NetFox; 5]kv1nQ  
import java.io.*; Lv)1 )'v0  
tp"eXA0n  
Qip@L WvT  
public class FileAccessI implements Serializable{ bx-:aC)]2  
_$8:\[J  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z63
y8  
RandomAccessFile oSavedFile; ra@CouR^c{  
long nPos; B oiS  
CLuQ=-[
|  
:S-{a  
public FileAccessI() throws IOException #B!M,TWf9s  
{ k2#|^N  
this("",0); wT,=C'  
} va"bw!zXo*  
2P=~6(  
L{XW2c$h  
public FileAccessI(String sName,long nPos) throws IOException [{>1wJ Pdj  
{ g^jTdrW/s  
oSavedFile = new RandomAccessFile(sName,"rw"); X<v1ES$  
this.nPos = nPos; _1YC9}  
oSavedFile.seek(nPos); =?\%E[j  
} `Hu2a]e9  
:/"5x  
iMV=R2t 2  
public synchronized int write(byte[] b,int nStart,int nLen) ZC^NhgX  
{ PH^Gj
m  
int n = -1; (bB"6 #TI  
try{ v@J[qpX  
oSavedFile.write(b,nStart,nLen); ?jvuTS2  
n = nLen; ZhC,nbM  
} oDt{;S8|]  
catch(IOException e) rz%^l1@-  
{ E>r7A5Uo  
e.printStackTrace (); *l%&/\  
} &xt GabNk  
)4,U  
s+=':Gcb(C  
return n; p3T:Y_  
} rJRg4Rog  
##alzC  
v}IhO~`uEq  
} Otf{)f  
s5*HS3D  
}iUpBn  
/* fILvEf4b  
**SiteInfoBean.java ~Jj~W+h  
*/ #veV {,g  
package NetFox; &zP>pQr`#  
(I+e@UUiL  
q_9 tbZ;  
public class SiteInfoBean { Wu$yB!  
V"}Jsr  
BP\6N%HC%&  
private String sSiteURL; //Site's URL |TR
+Wn  
private String sFilePath; //Saved File's Path @:>gRD  
private String sFileName; //Saved File's Name h b8L[ 4  
private int nSplitter; //Count of Splited Downloading File {:Kr't<XzF  
?|\wJrM ]  
B`jq"[w]-  
public SiteInfoBean() 1i)3!fH0:  
{//nSplitter的缺省值为5 2n-kJl`: O  
//default value of nSplitter is 5 h[<l2fy  
this("","","",5); GY^;$?  
} {.y_{yWo  
C46jVl  
H(y Gh  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Tb8r+~HK  
{ deTD|R  
sSiteURL= sURL; dT (i*E\j  
sFilePath = sPath; #5{BxX&\  
sFileName = sName; MpIiHKQ G9  
this.nSplitter = nSpiltter; P|C5k5  
1083p9Uh  
~CdW:t  
} d9%P[(yM^
 
j9vK~_?;  
[8 H:5Ho  
public String getSSiteURL() Q7tvpU  
{ 6GqC]rd*:  
return sSiteURL; /{W6]6^  
} tvq((2  
#l7v|)9v  
S_;r!.
  
public void setSSiteURL(String value) o
/n4M]G  
{ t`>Z#=cl\  
sSiteURL = value; yO*   
} 5OX[)Li  
Ps[#z@5{x  
%&q}5Y4!  
public String getSFilePath()  nb6Y/`G  
{ KeXt"U  
return sFilePath; aUA)p}/:  
} tCar:p4$  
#3'M>SaoH  
kQQDaZ8  
public void setSFilePath(String value) *v?kp>O  
{ c& bms)Jwa  
sFilePath = value; ^Xu4N"@  
} ;Zr7NKs  
zgH*B*)bj  
4??LK/s*  
public String getSFileName()  ARs]qUY  
{ =2ED w_5E  
return sFileName; g2=PZR$  
} y~VI,82*  
$em'H,*b3  
)S/=5Uc  
public void setSFileName(String value) V w58w`e  
{ 8F@Sy,D  
sFileName = value; m7u`r(&  
} 0z4M/WrNt  
ItZYOt|Hn  
ju.pQ=PSX  
public int getNSplitter() 5C^@w
 
{ I3d}DpPx%  
return nSplitter; JY^i  
} Dg{d^>T!_x  
N^@:+,<3  
;[(d=6{hc]  
public void setNSplitter(int nCount) sf->8  
{ Bx#=$ka  
nSplitter = nCount; \<09.q<8  
} `Pc<0*`a  
} !6@'H4cb=  
-5ZmIlL.S  
BMuEfa^  
/* \iP@|ay9  
**Utility.java Ym!e}`A\F  
*/ Eh|,[D!E  
package NetFox; BenyA:W"  
XoL DqN!  
I~@8SSO,vH  
public class Utility { Z@f{f:Jc/"  
gq/Za/!6  
n|XheG7:  
public Utility()  (/,l0  
{ xIC@$GP  
=WBfaxL}  
TsGx2[  
} |D%mWQng  
K7K/P{@9[9  
//线程睡眠 o[iN/  
public static void sleep(int nSecond) 8&| o  
{ KAI2[ gs  
try{ +@?'dw  
Thread.sleep(nSecond); 1EEcNtpub]  
} NRx I?v  
catch(Exception e) -)VjjKz]8  
{ 
Lhe&  
e.printStackTrace (); {uoF5|O6K  
} s.Ai_D  
} x
\8|A  
3}F>t{FDk  
//日志 El;"7Qn  
public static void log(String sMsg) Jou*e%  
{ tqCkqmyC  
System.err.println(sMsg); ' BS.:^  
} (;%T]?<9#  
q!@!eC[b  
ZH9Fs'c=  
public static void log(int sMsg) =DDKGy.g  
{ vZ"gCf3#?3  
System.err.println(sMsg); m m`#v g,  
} \AKP ea=  
} /#H P;>!n  
=\5WYC  
G[yzi  
/* z+{qQ!  
**TestMethod.java ,f$P[c  
*/ k:R\;l5  
package NetFox; ]\_tO  
3Z=yCec]  
;p`to"6IFD  
public class TestMethod { ~uty<fP  
/pPHD]  
P=jsOuW  
public TestMethod() 4Z~ nWs  
{ ///xx/weblogic60b2_win.exe -bzlp7q*  
try{ H>%AK'

'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); aaT3-][  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); cK u[4D
{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k'#3fz\  
fileFetch.start(); \GxqE8  
} #]tDxZ] 6  
catch(Exception e){e.printStackTrace ();} Hy&Z0W'
l  
@:GqOTN  
]Z8u0YtM)  
} 4^l9d  
4oiE@y&{4  
`cXLa=B)9  
public static void main(String[] args) c]aU}[s1  
{ t~/:St  
new TestMethod();
":M]3.  
} -oyA5Yx0  
} rSJ!vQo Cb  
点击下载更多相关资料