http断点续传简单实现（java)

/* zy'cf5k2  
**SiteFileFetch.java fzjAP7 y  
*/ GEtzLaq<  
package NetFox; M6XpauR-  
import java.io.*; \`Ow)t:  
import java.net.*; "g:1br?X,9  
!U4<4<+  
jP}Ix8vc=  
public class SiteFileFetch extends Thread { DE!c+s_g4  
R?iC"s!  
T.pc3+B8N  
SiteInfoBean siteInfoBean = null; //文件信息Bean [(*?  
long[] nStartPos; //开始位置 Y>Fh<"A|$  
long[] nEndPos; //结束位置 2k M;7:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Eal*){"<,?  
long nFileLength; //文件长度 \^x`GsVy  
boolean bFirst = true; //是否第一次取文件 E-Y4TBZ*  
boolean bStop = false; //停止标志 kV:T2}]|H  
File tmpFile; //文件下载的临时信息 UZx8ozv'  
DataOutputStream output; //输出到文件的输出流 ,f}u|D 3@  
!yD$fY  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） tA{hx-  
public SiteFileFetch(SiteInfoBean bean) throws IOException x*!%o(G  
{ \EW<;xq  
siteInfoBean = bean; qu%}b
>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); nR8r$2B+t  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,vB~9^~  
if(tmpFile.exists ()) x};sti R  
{ $3]]<oH  
bFirst = false; SGP)A(,k9  
read_nPos(); 8:fq!m  
} ndHUQ$/(  
else |syvtS{  
{ xTf|u  
nStartPos = new long[bean.getNSplitter()]; 1<;G oC"  
nEndPos = new long[bean.getNSplitter()]; fVz0H1\J&  
} #j4RX:T*[  
&vN^*:Q
 
S
#*aB2ZS  
N"A`tc5&  
}  w\y)  
<op|yh3Jkk  
w7Ij=!)  
public void run() qaG8:  
{ dy3fZ(=q^  
//获得文件长度 T\w{&3ONm  
//分割文件 c' Q4Fzj0'  
//实例FileSplitterFetch om2)Cd9~7  
//启动FileSplitterFetch线程 tL]T_]z  
//等待子线程返回 d~#:t~ $,  
try{ ;k (M4?  
if(bFirst) @ RP?)*8}&  
{ -+y3~^EYm,  
nFileLength = getFileSize(); 22@w:  
if(nFileLength == -1) n;e.N:p  
{ WSbD."p<  
System.err.println("File Length is not known!"); [oOV@GE  
} a/xnf<(H  
else if(nFileLength == -2) N#GMvU
#R  
{ 5#~E[dr  
System.err.println("File is not access!"); <-"[9 w  
} w+gPU1|(r  
else ={\9-JJhE  
{ 4}NCdGD  
for(int i=0;i<nStartPos.length;i++) +}iuTqu5  
{ b<j*;n.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5M\bH'1  
} f&!{o=  
for(int i=0;i<nEndPos.length-1;i++) |:pBk:  
{ <&l@ ):a  
nEndPos = nStartPos[i+1]; Y_/w}HB   
} E|y   
nEndPos[nEndPos.length-1] = nFileLength; h-6x! 6pm  
} Y'yGhpT~  
} ;%Kh~  
M8${&&[;  
t8.^YTI  
//启动子线程 Bdm05}c@u  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~uu{ v')  
for(int i=0;i<nStartPos.length;i++) ^/)%s3  
{ L:7 kp<E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mD7kOOMY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3&zcdwPj  
nStartPos,nEndPos,i); |?t}7V#[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {_ {zs!r  
fileSplitterFetch.start(); vn
gn^2  
} xM$AhH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qVE<voB8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S|]\q-qA&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", gP`CQ0t  
nEndPos = " + nFileLength); R%"'k<`#  
// fileSplitterFetch[nPos.length-1].start(); PAXm  
:"gu=u!  
 ?%*p!m  
//等待子线程结束 :kvQ3E0  
//int count = 0; V^< Zs//7  
//是否结束while循环 pYh\l.@qf  
boolean breakWhile = false; yM*_"z!L  
y>0Gmr  
Jk57| )/  
while(!bStop) T@d4NF#  
{ bzh:  
write_nPos(); )!Zm*(  
Utility.sleep(500); lsU`~3nr  
breakWhile = true; Iz8gZ:rd0  
2E0oLl[  
D~)bAPAD  
for(int i=0;i<nStartPos.length;i++) 3x)jab  
{ D!mx&O9  
if(!fileSplitterFetch.bDownOver) yT
[)V[}  
{ ,6aF~p;wI|  
breakWhile = false; ;N!opg))d<  
break; 0E#?H0<OeG  
} cUTG! P\R  
} Va^(cnwa  
if(breakWhile) yC7lR#N8j0  
break; u5tUm  
.9q`Tf  
RO| }WD)  
//count++; VBz G`&NG  
//if(count>4) Z GrDa  
// siteStop(); 6S^JmYq  
} @zT2!C?^L  
}$#PIyz  
H__'K/nH+  
System.err.println("文件下载结束！"); 1cD  
} ]xPy-j6C  
catch(Exception e){e.printStackTrace ();} 0qL.Rnt  
} zGa V^X  
,,;vG6^a  
{Gw{W&<  
//获得文件长度 t(UdV  
public long getFileSize() 04:QEC"9mj  
{ 3-BC4y/  
int nFileLength = -1; =d/
$B!t{  
try{ P?K
g7m W  
URL url = new URL(siteInfoBean.getSSiteURL()); T}Wse{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9JO1O:W  
httpConnection.setRequestProperty("User-Agent","NetFox"); TPmb]j  
7#C3E$gn?  
,%U\@*6=  
int responseCode=httpConnection.getResponseCode(); Y^eF(  
if(responseCode>=400) !e}4>!L,(^  
{ o_&Qb^W  
processErrorCode(responseCode); g#o9[su  
return -2; //-2 represent access is error X?Or.  
} .\8LL,zT  
3\K;y>NK  
e8{!Kjiz  
String sHeader; );{76  
;#=y5Q4  
} wx(P3BHD  
for(int i=1;;i++) Mg&<W#$K  
{ DS;.)P"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Nb)Mh  
//Utility.log(in.readLine()); ( ;_AP.  
sHeader=httpConnection.getHeaderFieldKey(i); "Rn@yZV  
if(sHeader!=null) UQjYWXvi  
{ b?:?"  
if(sHeader.equals("Content-Length")) G-'CjiMu  
{ PsBLAr\ah  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u24XuSe$  
break; -_bDbYL  
} [^gb6W9Y  
} o90[,  
else p,14'HS%@  
break; v.c.5@%%o  
} 6E9o*YSk  
} a0's6C  
catch(IOException e){e.printStackTrace ();} 5m\)82s  
catch(Exception e){e.printStackTrace ();} 5>h/LE]"  
4GS:kfti  
I>lblI$7  
Utility.log(nFileLength); 37*2/N2  
zb.sh  
S 9;FD3  
return nFileLength; ,m
M7g  
} <DhuY/o  
2\CZ"a#[  
Z<'iT%6+r  
//保存下载信息（文件指针位置） S$/SFB$)~W  
private void write_nPos() l@`n4U.Gwl  
{ {dlG3P='`f  
try{ 3U*4E?g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0O(Vyy  
output.writeInt(nStartPos.length); (O/W`qo  
for(int i=0;i<nStartPos.length;i++) Ss:'HH4  
{ 1jd.tup  
// output.writeLong(nPos); y:k7eE"  
output.writeLong(fileSplitterFetch.nStartPos); \W|ymV_Ki  
output.writeLong(fileSplitterFetch.nEndPos); \/9O5`u*V  
} .Dy2O*`  
output.close(); r9p ((ir  
} I_|W'%N]  
catch(IOException e){e.printStackTrace ();} ~I]aUN  
catch(Exception e){e.printStackTrace ();} O~Svk'.)  
} fC/P W`4Ae  
v)nBp\fjxp  
X$eR RSW  
//读取保存的下载信息（文件指针位置） B[5<&  
private void read_nPos() Gz2\&rmN  
{ /as+ TU`A  
try{ 
_5o5/@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); TJ|do`fw>  
int nCount = input.readInt(); **c"}S6:mC  
nStartPos = new long[nCount]; dJ~Occ1~r  
nEndPos = new long[nCount]; xPJ@!ks9  
for(int i=0;i<nStartPos.length;i++) 10_>EY`  
{ sTvw@o*  
nStartPos = input.readLong(); uEkGo5  
nEndPos = input.readLong(); ;aH3{TS  
} n{=Ot^ ";  
input.close(); /< Dtu UM  
} ?y,KN}s_  
catch(IOException e){e.printStackTrace ();} rj/nn)vv;  
catch(Exception e){e.printStackTrace ();} [Bj\h7G
 
} w8F`RRHEE  
'fZ\uMdTx  
hJ?PV@xy
 
private void processErrorCode(int nErrorCode) ^~s!*T)\  
{ H-eHX3c7  
System.err.println("Error Code : " + nErrorCode); NleMZ  
} 9 $^b^It  
eL [.;_  
{&J OO  
//停止文件下载 ITD&wg  
public void siteStop() *P?Rucg  
{ c`oW-K{  
bStop = true; +y\o^w4sT  
for(int i=0;i<nStartPos.length;i++) C%#u2C2  
fileSplitterFetch.splitterStop(); }4?z<.V  
pz"}o#R"x  
- x;xQ  
} n^<J@uC  
} k|$?b7)"@  
//负责部分文件的抓取 bpa
'`sf  
**FileSplitterFetch.java PmtXD6p3(  
*/ Lc
(eY{CY  
package NetFox; yoM^6o^
,D  
M3eFG@,  
bQdu=s[  
import java.io.*; Kp19dp}'b  
import java.net.*; #P {|7}jk  
FJFO0Hb6
  
bd2QQ1[1vh  
public class FileSplitterFetch extends Thread { !Oi':O
QG  
-*qoF(/U  
<KX+j,4  
String sURL; //File URL Nl^uA  
long nStartPos; //File Snippet Start Position bnH:|-?q  
long nEndPos; //File Snippet End Position |<%v`*  
int nThreadID; //Thread's ID D#[<N  
boolean bDownOver = false; //Downing is over lkJe7 +s  
boolean bStop = false; //Stop identical ^_BjO(b'e  
FileAccessI fileAccessI = null; //File Access interface 4h T!D
S  
RQ4+EW1
G  
|gU)6}V@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException BN6cu9a  
{ EtQ:x$S_  
this.sURL = sURL; 24\^{3nOK  
this.nStartPos = nStart; 3Te&w9K  
this.nEndPos = nEnd; 1! 5VWF0  
nThreadID = id; Cv;#8Wj}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 JD9
=gBN\?  
} N;4wbUPL7h  
B &3sV+  
2I
7|hZ,  
public void run() o3:BH@@  
{ m=a^t  
while(nStartPos < nEndPos && !bStop) a'O-0]g,  
{ JW"n#sR4  
Bve',.xH  
eV"Uv3  
try{ dV /Es  
URL url = new URL(sURL); .UvDew/Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >u]9(o7I  
httpConnection.setRequestProperty("User-Agent","NetFox"); ((M>To_l  
String sProperty = "bytes="+nStartPos+"-"; fh`}~ aQ  
httpConnection.setRequestProperty("RANGE",sProperty); MjbgAH-  
Utility.log(sProperty); h)s&Nqg1B  
w%(D4ldp   
9U3.=J  
InputStream input = httpConnection.getInputStream(); <@c@`K  
//logResponseHead(httpConnection); )5u#'5I>  
Iu^I?c[  
iu2O/l#r  
byte[] b = new byte[1024]; Z:diM$Z?7  
int nRead; :k2J &@8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0qm CIcg  
{ h-U]?De5\  
nStartPos += fileAccessI.write(b,0,nRead); qKE
+,g'  
//if(nThreadID == 1) 6q,CEm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (px3o'lsh  
} 'Z)#SzY
 
AYDAt5K_  
}|)T<|Y;  
Utility.log("Thread " + nThreadID + " is over!"); Hm+VGH'H?  
bDownOver = true; 2'Raj'2S4  
//nPos = fileAccessI.write (b,0,nRead); }0]iS8*tL  
} PGuPw'2;[  
catch(Exception e){e.printStackTrace ();} X_)x Fg'k  
} @X P_~ N  
} .pH 4[~  
/?a9g>G%N  
aO2zD<d  
//打印回应的头信息
! 6R|  
public void logResponseHead(HttpURLConnection con) ->Fsmb+R  
{ !E,|EdIr  
for(int i=1;;i++) 7/K'nA  
{ w}8=sw  
String header=con.getHeaderFieldKey(i); l9n$cv^  
if(header!=null) F2Gg_u@7M  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 
Vddod  
Utility.log(header+" : "+con.getHeaderField(header)); XANJA  
else 3ouo4tf$H.  
break; )JU`Z@?8  
} h!tg+9%  
} "![KQ  
ZgmK~iJ  
{fY(zHC  
public void splitterStop() >y$*|V}k  
{ =E:sEw2j  
bStop = true; 4b}'W}  
} NOf{Xx<#k  
N:EljzvP}  
=6N=5JePB  
}
ReGT*+UN  
3@* ~>H  
Iz&d S?p_  
/* ?"kU+tCxg  
**FileAccess.java =@nW;PUZ  
*//文件访问(定位，写) L!fIAd`  
package NetFox; @Ph'!  
import java.io.*; ]qx!51S  
y^D3}ds  
u,~+ho@  
public class FileAccessI implements Serializable{ ^ '_Fd  
a(uQGyr[k1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?OGs+G  
RandomAccessFile oSavedFile; IvI;Q0E-3  
long nPos; Z/:W.*u  
?.ofs}  
;zSV~G6-  
public FileAccessI() throws IOException < B!f;  
{ )iZhE"?z  
this("",0); DLO#_t^v.  
} )i:"cyoE  
y,c\'}*H  
ZIc-^&`r=  
public FileAccessI(String sName,long nPos) throws IOException g^U-^f  
{ a, `B.I  
oSavedFile = new RandomAccessFile(sName,"rw"); K3&k+~$  
this.nPos = nPos; 8jiBLZkRf  
oSavedFile.seek(nPos); k8cR`5@PK  
} 5nK|0vv%2  
89W8c
J$yW  
>n1UK5QD  
public synchronized int write(byte[] b,int nStart,int nLen) "o@R}_4]q  
{ -*2b/=$u  
int n = -1; 3Qp6$m  
try{ c~6ywuq+M`  
oSavedFile.write(b,nStart,nLen); I,V'J|=j  
n = nLen; bHzZ4i  
} [
3
qJUJM  
catch(IOException e) >f;oY9 {m  
{ lxBcO/  
e.printStackTrace (); |r4&@)  
} ,pW^>J  
{@Z*.G^  
$$R->  
return n; 8:]5H}Hi  
} lg@q} ]1  
5^Lb
c.h  
]agdVr^  
} bf[l4$3k  
MN>U jFA  
rWBgYh  
/* $<f+CtD4  
**SiteInfoBean.java ePxf.U  
*/ zj=F4]w  
package NetFox; 'NnmLM(oh  
o/!a7>xO4  
C%P.`NxA  
public class SiteInfoBean { 7f~7vydZ}  
w!Z,3Yc)  
/|<0,ozoJ  
private String sSiteURL; //Site's URL @2\UjEo~  
private String sFilePath; //Saved File's Path u;8
bbv4  
private String sFileName; //Saved File's Name U*T :p>&  
private int nSplitter; //Count of Splited Downloading File Kn\$\?u  
,- _ReL  
J^Wqa$<;"  
public SiteInfoBean() ],wzZhA  
{//nSplitter的缺省值为5 O^R^Aw  
//default value of nSplitter is 5 8)J,jh9q  
this("","","",5); ;kVo? W]  
} &<C&(g{Z  
m h|HEkM  
ry4:i4/[  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >*}m.'u  
{ dw7h@9\y  
sSiteURL= sURL; {7=k/Y*U  
sFilePath = sPath; `UkPXCC\1  
sFileName = sName; [wJl]i  
this.nSplitter = nSpiltter; QSOJHRl=C  
BFn}~\wzK  
?=?9a  
} yF^)H{yx  
opCQ=G1  
AOCiIPw  
public String getSSiteURL() ,E4qxZC(X  
{ Zr;(a;QKs  
return sSiteURL; yn{U/+  
} ' @j8tK  
oF0*X$_X  

r}t%DH  
public void setSSiteURL(String value) oc&yz>%q  
{ @wXo{p@W  
sSiteURL = value; 6r)qM)97  
}
om,=.,|Ld  
R=HcSRTkA  
vu)V:y  
public String getSFilePath() DFqVZ  
{ jyjK~!0  
return sFilePath; h,'m*@Eg  
} }sGH}n<9*  
i(<do "Am<  
8f#&CC!L  
public void setSFilePath(String value) 6z+*
H7Qz  
{ s,GGO3^  
sFilePath = value; =7U8`]WA  
} $ZE"o`=7  
:*lB86Ly  
fehM{)x2:  
public String getSFileName() 2lBu"R6}  
{ rjT!S1Hs  
return sFileName; mg4:N  
} zMN4cBL9m  
skfFj&_T  
)TgjaR9G  
public void setSFileName(String value) 'I)E.DoF  
{ 3)qtz_,H/g  
sFileName = value; <}Rr C#uiA  
} ^VB_>|UN4  
-"3<Ll  
N/mC,7Q  
public int getNSplitter() -o0~xspF  
{ {-\VX2:;[9  
return nSplitter; 2<5s0GT'/  
} NU|T`gP  
"@E(}z'sM  
=n
N&8vRH  
public void setNSplitter(int nCount) WqRg/  
{ :+|os"  
nSplitter = nCount; D|!^8jHj  
} i6h , Aw3  
} E@\bFy_!>b  
uCpk1d  
B1a&'WX?  
/* *Z"(K\1TH  
**Utility.java |Xl,~-.  
*/ 4*9:  
package NetFox; 1PJ8O|Zt8  
Ot_xeg;7  
P(za8l
>  
public class Utility { ws$!-t4<(  
t6O/Q0_  
AW:WDNQh8n  
public Utility() mEe JK3D[  
{ "5R8Zl+  
%8yX6`lH  
P$i?%P~  
} |^E#cI  
UGJ# "9  
//线程睡眠 q#N8IUN}4  
public static void sleep(int nSecond) ro4 XA1  
{ KBo/GBD]|  
try{ nr<&j#!L  
Thread.sleep(nSecond); p<3^= 8Y$  
} j5;eSL@/  
catch(Exception e) K"r'w8P  
{ }x1*4+Y1  
e.printStackTrace (); k
ycZ  
} Jm8#M z  
} D0=H&Z[  
P:yMj&)  
//日志 niV=Ijt{5  
public static void log(String sMsg) fu95-)M  
{ 0@ 9em~  
System.err.println(sMsg); 64OgE!  
} 
+LM/< l  
k%Q>lf<e   
7$7Y)&\5w  
public static void log(int sMsg) [/ E_v gZ  
{ wDV%.Cc  
System.err.println(sMsg); Yg6 f  
} qwU,D6  
} TY3WP
$u  
I)Dd"I  
lT3,G#(  
/* ,#42ebGHR  
**TestMethod.java ~cSOni`  
*/ s:y=X$&M  
package NetFox; *a7&v3X  
Svo gvn  
u;Q'xuo3  
public class TestMethod { b;O|-2AR  
nx >PZb  
%Ln7{w  
public TestMethod() Y|=/*?o}  
{ ///xx/weblogic60b2_win.exe tF<|Eja*  
try{ q|. X[~e|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FU|c[u|z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
%K_[Bx{B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8ctUK|
 
fileFetch.start(); Yl+r>+^  
} W|@/<K$V  
catch(Exception e){e.printStackTrace ();} {
Ah\-{]  
r~uWr'}a}  
GyO
o$FW  
} +_HPZo  
 zF2GW  
joh=0nk;D  
public static void main(String[] args) <=*xwI&q  
{ +`==US34  
new TestMethod(); 6t|FuTC  
} Oi=>Usd  
} YN ~7nOw  
点击下载更多相关资料