http断点续传简单实现（java)

/* -_t4A *  
**SiteFileFetch.java I*.nwV<  
*/ 02t({>`  
package NetFox; 4;Ucas6  
import java.io.*; E
|c(#P{  
import java.net.*; 1k4\zVgi  
LJ~#0Zu?  
E7iAN\vo  
public class SiteFileFetch extends Thread { 3W[?D8yi)  
D tZ?sG  
@a@}xgn{  
SiteInfoBean siteInfoBean = null; //文件信息Bean _xCYh|DlQ|  
long[] nStartPos; //开始位置 aq_K,li#w  
long[] nEndPos; //结束位置 }p*|8$#x"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Tph^o^  
long nFileLength; //文件长度 6H'A]0  
boolean bFirst = true; //是否第一次取文件 AE~a=e\x  
boolean bStop = false; //停止标志 %Hd[,duwO  
File tmpFile; //文件下载的临时信息 Ez|NQ:o  
DataOutputStream output; //输出到文件的输出流 3JQ7Cc>  
*4%pXm;  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EOu[X'gLr  
public SiteFileFetch(SiteInfoBean bean) throws IOException d%0Gsga}  
{ q`r| DcN~  
siteInfoBean = bean; v%cCJ SO#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /A,w{09G  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); . KLEx]f.  
if(tmpFile.exists ()) rN|=cn  
{ #)~u YQ  
bFirst = false; 63l& ihj  
read_nPos(); bKsjbYuo  
} a`xAk^w+  
else 8]`#ax 5  
{ .c}+kHv  
nStartPos = new long[bean.getNSplitter()]; h
J`Gu7  
nEndPos = new long[bean.getNSplitter()]; */IiL%g4u  
} /_m)D;!y  
]$L5}pE3  
(o B4*  
S=) c7t?a  
} v%T'!(0j/  
a r8iuwfZ  
$?W2'Xm!V  
public void run() q
}L`8(a  
{ 5xdeuBEY8  
//获得文件长度 ?lD)J?j  
//分割文件 ;&CLb`<y  
//实例FileSplitterFetch b;jdk w|  
//启动FileSplitterFetch线程 $k0(iFzR1  
//等待子线程返回 H;\C7w|  
try{ j8Z;}Ps  
if(bFirst) K\9CW%W  
{ a-|pSe*rx  
nFileLength = getFileSize(); k/{WlLN  
if(nFileLength == -1) *t| !xO  
{ gC2}?nq*  
System.err.println("File Length is not known!"); IXtG 36O  
} 8Y`g$2SZ^8  
else if(nFileLength == -2) .kU^)H"l  
{ ~|S0E:*.  
System.err.println("File is not access!"); (CIcM3|9C  
} G-)e(u   
else K0( S%v|,}  
{ iS+"Jsz  
for(int i=0;i<nStartPos.length;i++) .kFO@:  
{ 7s6+I_n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); CBf[$[e  
} %k4Qx5`?d  
for(int i=0;i<nEndPos.length-1;i++) sPZwA0%  
{ hJ ^+asr  
nEndPos = nStartPos[i+1]; b]z_2h~`  
} 1Zc=QJw@  
nEndPos[nEndPos.length-1] = nFileLength; .+(
V</  
} F\+AA  
} FhY#3-jH  
'(B -{}l  
~wuCa!!A  
//启动子线程 yC
1OeO8{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {p1`[R&n#  
for(int i=0;i<nStartPos.length;i++) AA[1[  
{ N8Rq7i3F?a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *nU5PSs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0yC~"u[N Y  
nStartPos,nEndPos,i); n',X,P
0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !1I# L!9  
fileSplitterFetch.start(); )M0(vog  
} Q/?`);  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &v .S_Ym  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); L>IP!.J]?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w;ZT-Fti  
nEndPos = " + nFileLength); <}[ !k<  
// fileSplitterFetch[nPos.length-1].start(); jw{N#QDh  
 :'F,l:  
,z
x{RDI  
//等待子线程结束 +Xw%X3o)  
//int count = 0; dQ{qA(m  
//是否结束while循环 C8|Ls(4Ck  
boolean breakWhile = false; ]'Eg2(wy  
zGU MH7 M  
~*1>)P8]#  
while(!bStop) ;6PU  
{ kbb!2`F!%  
write_nPos(); 95#]6*#[4!  
Utility.sleep(500); J8S$YRZ_  
breakWhile = true; T2Z$*;,>T  
HI|egf@  
<jJ'T?,  
for(int i=0;i<nStartPos.length;i++) 05ClPT\BCr  
{ 0'*{BAWx  
if(!fileSplitterFetch.bDownOver) ]*| hd/j  
{ 9*I[q[>9  
breakWhile = false; =JE<oVP8  
break; wicsf<]  
} #Q7:Mu+  
} z8a{M$-Q
 
if(breakWhile) .B~yI3D`M  
break; B)@X
z<Q  
rT4Q^t"  
uxL+oP0  
//count++; QDYuJ&!h  
//if(count>4) C2rG3X^~Jm  
// siteStop(); S\N l|U[  
} " J9
 
BN]o!Y  
j7&#R+f  
System.err.println("文件下载结束！"); M**Sus87Q  
} gD)M7`4  
catch(Exception e){e.printStackTrace ();} s3A(`heoq  
} Wtu-g**KN  
9{fP.ifdv7  

TW&s c9  
//获得文件长度 #\X)|p2  
public long getFileSize() }bw^p.ci  
{ Te}gmt+#%  
int nFileLength = -1; 16Ka>=G  
try{ Fu{VO~w  
URL url = new URL(siteInfoBean.getSSiteURL()); geK;r0(f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !%R):^R8  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ld_uMe?Z  
LI}e_=E  
)2y [#Blo  
int responseCode=httpConnection.getResponseCode(); !
U@ETo  
if(responseCode>=400) NqF*hat  
{ KtAEM;g  
processErrorCode(responseCode); *bpN!2  
return -2; //-2 represent access is error E7h@Y~bNhW  
} N:3=G`Ws  
Pn^:cr|  
[p'2#Et  
String sHeader; *%jXjTA0D  
U>!TM##1QD  
k8ILo)  
for(int i=1;;i++) 4S4MQ  
{ Nk-xnTZ"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8t=H  
//Utility.log(in.readLine()); _"Y7}A\9  
sHeader=httpConnection.getHeaderFieldKey(i); wE1GyN  
if(sHeader!=null) />Zfx.Aj6  
{ &#C&0f8PnD  
if(sHeader.equals("Content-Length")) r|}Pg}O  
{ 7<70\6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5,XEN$^  
break; *.w6=}  
} 1 M!4hM Q  
} f1SKOq  
else O2Y|<m  
break; oVk!C a  
}  Yf[Cmn  
} $G0e1)D  
catch(IOException e){e.printStackTrace ();} %9zpPrWF  
catch(Exception e){e.printStackTrace ();} DmgDhNXKq  
lv]U)p  
.=}\yYGe  
Utility.log(nFileLength); {@Lun6\  
+~F>:v?Rh  
#"A`:bjG  
return nFileLength; 5);"()g32  
} IW nG@!  
1H">Rb30@  
P2ySjgd  
//保存下载信息（文件指针位置） vRaxB  
private void write_nPos() 4 w*m]D{  
{ }L Q%%  
try{ mgjcA5z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gF9GU5T:  
output.writeInt(nStartPos.length); @+~URIG)  
for(int i=0;i<nStartPos.length;i++) [%LGiCU]  
{ `@\FpV[|P  
// output.writeLong(nPos); ?-&k?I  
output.writeLong(fileSplitterFetch.nStartPos); ?7C
dJgJp  
output.writeLong(fileSplitterFetch.nEndPos); 2vUcSKG7  
} D3g5#.$,}>  
output.close(); G@
D8[  
} (oiQ5s^f  
catch(IOException e){e.printStackTrace ();} '#A_KHD  
catch(Exception e){e.printStackTrace ();} 9BOn8p;yz  
} p79QEIbk=  
-|#/KKF  
W1o6Sh8v(  
//读取保存的下载信息（文件指针位置） KpG'E  
private void read_nPos() cJm},  
{ uHf1b?W  
try{ .I{u[ "  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K ..Pn17t  
int nCount = input.readInt(); e"EGqn&!  
nStartPos = new long[nCount]; 'Eia=@  
nEndPos = new long[nCount]; DfkGNBY  
for(int i=0;i<nStartPos.length;i++) 0
"@J*e#  
{ QN#Lbsd  
nStartPos = input.readLong(); b[&ri
:AC  
nEndPos = input.readLong(); , =*^XlO=c  
} 7dB_q}<  
input.close(); NmpNme  
} WB (?6"  
catch(IOException e){e.printStackTrace ();} "<^ Vp
-7r  
catch(Exception e){e.printStackTrace ();} Y._ACQG3  
} 'YN:c
r,V  
fUq}dAs*K  
RigS1A\2l  
private void processErrorCode(int nErrorCode) 9nO&d(r g  
{ ^|U5
@u_  
System.err.println("Error Code : " + nErrorCode); `K$;K8!1  
} dEf5x_TGm  
~nj+"d]  
,{"K^  
//停止文件下载 .,thdqOO  
public void siteStop() o}wRgG  
{ [D?xd/G  
bStop = true; %PR,TWe  
for(int i=0;i<nStartPos.length;i++) e7
Gb7c~  
fileSplitterFetch.splitterStop(); D][I#vh  
fe6Op  
D@{m
  
} d`?EEO  
} $WE_aNfja  
//负责部分文件的抓取 %0815 5M  
**FileSplitterFetch.java <T'fJcR  
*/ b5|l8<\  
package NetFox; [m x}n+~  
- 3<&sTR  
/'v!{m  
import java.io.*; `x L@%  
import java.net.*; yYaYuf  
)zP"Uuu  
L^s?EqLXS  
public class FileSplitterFetch extends Thread { E/% F0\B  
I2z7}*<u  
Br$/hn=  
String sURL; //File URL '/ueY#eG  
long nStartPos; //File Snippet Start Position +~ S7]AZ  
long nEndPos; //File Snippet End Position |CS&H2!s  
int nThreadID; //Thread's ID >Zf*u;/dW$  
boolean bDownOver = false; //Downing is over su-0G?c  
boolean bStop = false; //Stop identical q{yzu
x  
FileAccessI fileAccessI = null; //File Access interface >X>]QMfh  
@X/
-p3729  
z%6egi>  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3U?^49bJ  
{ SN QLEe  
this.sURL = sURL; l29AC}^  
this.nStartPos = nStart; ]?jmRk^.  
this.nEndPos = nEnd; G
v(n2r  
nThreadID = id; <(qdxdUp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 e [F33%  
} b]8\%=d  
I= z+`o8  
.lcgM  
public void run() jd+HIR  
{ !wrAD"l*@  
while(nStartPos < nEndPos && !bStop) 9I|Q`j?p`  
{ {#{nU NW  
% e70*;  
$i `@0+:  
try{ 2[Qzx%Vp  
URL url = new URL(sURL); F<6{$YI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (ub
K i[)  
httpConnection.setRequestProperty("User-Agent","NetFox"); A_6Dol=J@  
String sProperty = "bytes="+nStartPos+"-"; B)-P#,}  
httpConnection.setRequestProperty("RANGE",sProperty); R?*-ZI[>w  
Utility.log(sProperty); %#]/]B/4  
?H!X p  
t6+>Zr  
InputStream input = httpConnection.getInputStream(); :~,akX$  
//logResponseHead(httpConnection); ZQJh5.B  
*41WZE  
5bWy=Xk B  
byte[] b = new byte[1024]; Rn whkb&&  
int nRead; MD+eLA7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
PzLV}   
{ -
1!s8G  
nStartPos += fileAccessI.write(b,0,nRead); ;u%4K$   
//if(nThreadID == 1) qSVg.<+   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `,wX&@sN  
} l%xeM!}  
sy9YdPPE  
T~N877  
Utility.log("Thread " + nThreadID + " is over!"); D <Fl7QAb  
bDownOver = true; o\yqf:V8  
//nPos = fileAccessI.write (b,0,nRead); kZ 9n@($B  
} SR\$fmo  
catch(Exception e){e.printStackTrace ();} k1WyV_3  
} ]0p*EB=C*  
} 23UXOY0BW  
vf_pEkx*wD  
@]{:juD~  
//打印回应的头信息 "6  
public void logResponseHead(HttpURLConnection con) SYK?5_804  
{ (pQ$<c  
for(int i=1;;i++) y\[GS
2nTX  
{ a% 82I::t  
String header=con.getHeaderFieldKey(i); &sPu3.p  
if(header!=null) Hkj| e6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); O`(it%Ho!  
Utility.log(header+" : "+con.getHeaderField(header)); O[')[uo8s  
else gq?~*4H  
break; >z8y L+  
} }(if|skau  
} E{|n\|  
+Sdki::  
s!BZrVM%I`  
public void splitterStop() t+SLU6j,  
{ j(=zc6m  
bStop = true; TsZX'Yn  
} E@;v|Xc  
1^=[k  
4=n%<U`Z/  
} p$%g$K  
 PYYO-Twg  
_:;j)J0  
/* d`Em)3v  
**FileAccess.java b(gcnSzM2  
*//文件访问(定位，写) m-!z(vcn  
package NetFox; \A3yM{G~+  
import java.io.*; 8uhB&qxB  
WN?meZ/N/  
'Xzi$}E D  
public class FileAccessI implements Serializable{ ^-7{{/  
H~"XlP  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 / k8;k56  
RandomAccessFile oSavedFile; Y3wL EG%,:  
long nPos; rO{"jJ  
mkmVDRK  
Kx[z7]1@  
public FileAccessI() throws IOException -[`FNTTV C  
{ Aonq;} V e  
this("",0); Th//uI+  
} }tZA7),L  
>pl*2M&  
oE4hGt5x{  
public FileAccessI(String sName,long nPos) throws IOException 3/hAxd  
{ /2!"_?<L  
oSavedFile = new RandomAccessFile(sName,"rw"); :WnXoL  
this.nPos = nPos; y7s.6i}7  
oSavedFile.seek(nPos); Y:="vWWG  
} V/-~L]G  
(gv ~Vq  
D+
**o  
public synchronized int write(byte[] b,int nStart,int nLen) M+TF0c  
{ ~d?\rj3=  
int n = -1; eDSBs
3k7H  
try{ Jid:$T>  
oSavedFile.write(b,nStart,nLen); 5{|\h}  
n = nLen; $pGk%8l%  
} wen6"  
catch(IOException e) {n%U2LVL  
{ $yb8..+  
e.printStackTrace (); Q-N.23\1  
}  qz:_T  
(Dl68]FX  
y0'"  
return n; w8g36v*+(u  
}  0-+`{j  
Vkb&' rXw+  
^i^S1h"  
} j{'@g[HW  
G1'w50Yu  
a[8_O-  
/* @]h#T4z'  
**SiteInfoBean.java AH],>i3  
*/ *H RxC  
package NetFox; thDE 1h  
~dwl7Qc  
K`2a{`  
public class SiteInfoBean { ?Xo9,4V1  
X|wXTecg*|  
#Y*AGxk  
private String sSiteURL; //Site's URL F'#e]/V1  
private String sFilePath; //Saved File's Path ;mb 6i_  
private String sFileName; //Saved File's Name
afc?a-~Z  
private int nSplitter; //Count of Splited Downloading File hK$-R1O  
y6?Q5x9M  
|T"{q  
public SiteInfoBean() tIC_/ 6  
{//nSplitter的缺省值为5 q& Vt*  
//default value of nSplitter is 5 Yazpfw 7'd  
this("","","",5); 6C/D&+4  
} Z
y7@"C  
d*,|?Ar*b  
:7!/FBd  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8LwbOR"  
{ 9H3#8T] ;  
sSiteURL= sURL; sEvJ!$Tt?I  
sFilePath = sPath; }%R6Su]y  
sFileName = sName; xt"/e-h}  
this.nSplitter = nSpiltter; T "G!H  
m x,X
!}  
.[Sv|;x"E  
} *<#&ne8  
a}c(#ZLs  
1 )j%]zd2  
public String getSSiteURL() Z?hBn`.  
{ }RUC#aW1  
return sSiteURL; 6]g
s{zG  
} `u-VGd\  
J= |[G'  
$9DZ5"  
public void setSSiteURL(String value) c/2OR#$t  
{ |#2
<4sd  
sSiteURL = value; km<~Hw>Z  
} WuGm~<NS  
#G{T(0<F  
6U+#ADo  
public String getSFilePath() uX0wg  
{ cdIy[ 1  
return sFilePath; xSOL4  
} {@, L  
IB*%PMTF  
$~~=SOd0  
public void setSFilePath(String value) 3.d=1|E  
{ -GKelz?h>  
sFilePath = value; LbYI{|_Js  
} ?n@PZL= ]  
(%fGS
.TR  
kkOYC?zE?  
public String getSFileName() Mc6Cte]3|  
{ nC&rQQFF  
return sFileName; @xkM|N?  
} _mkI;<d]$T  
63u'-Z"4  
)sS<%Xf  
public void setSFileName(String value) @e0Q+
t  
{ [7s5Vt|  
sFileName = value; ;Ok11wOw  
} ?<LG(WY  
n'h )(^  
w\2[dd  
public int getNSplitter() r2H'r ,N  
{ rP\7C+  
return nSplitter;  +NXj/  
} f@/qW!o
 
X"1<G3m4  
eO9nn9lql  
public void setNSplitter(int nCount) l9L;Tjj  
{ 1VZ>*Tl  
nSplitter = nCount; <?J7Z|  
} 9H)uTyuNi  
}  7:p]~eM)  
c,~44Z  
J/=A f [  
/* YJ6vyG>%C  
**Utility.java Vut.oB$ ~  
*/ R{rV1j#@!a  
package NetFox; a"1$z`ln  
s
]&y\Z  
EqmJXDm  
public class Utility { N7jRdT2k%  
CM#EA"9  
0$_imjZ  
public Utility() `i:0dVs  
{ 7lj-Z~1  
}mGD`5[`  
aKUr":z  
} |zT0g]WH  
i-=ff  
//线程睡眠 -$kJERvy  
public static void sleep(int nSecond) h9-Ky@X`  
{ y^Jv?`jw  
try{ jbGH3 L  
Thread.sleep(nSecond); RQ'c~D)X  
} dB,#`tc=,  
catch(Exception e) w:LCm `d  
{ 4>Y\2O?**  
e.printStackTrace (); ).boe& .  
} %i "  
} *Fc&DQT(  

;' W5|.ZN  
//日志 !?>)[@2 k6  
public static void log(String sMsg) H.mG0x`M"E  
{ y,>m#6hx#  
System.err.println(sMsg); :y %~9=  
} ^MW%&&,BL  
)/AvWDKvO  
Iq=B]oE  
public static void log(int sMsg) 8WGM%n#q  
{ :V2Q n-N  
System.err.println(sMsg); prs<ZxbQb  
} Xda<TX@-  
} D6oby*_w  
_Kj.  
c>
!J@[,  
/* -:>#w`H  
**TestMethod.java 7EO&:b]  
*/ DnFl*T>  
package NetFox; q{ 1U  
}\{1`$*~  
vTEkh0Ys  
public class TestMethod { 79x9<,a)  
7x]nY.\
 
{4 d$]o0V  
public TestMethod() %Eh%mMb^  
{ ///xx/weblogic60b2_win.exe u_"h/)C'H  
try{ -YyH"f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r97[!y1gt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Rx"Qwi,\U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )It4al^\  
fileFetch.start(); <^_?hN8.  
} @]tGfr;le&  
catch(Exception e){e.printStackTrace ();} 15:@pq\  
TjK5UML  
$I36>  
} yy1r,dw  
<3x#(ms!!  
Lx{N%;t*E  
public static void main(String[] args) @b{u/:y  
{ &FVlTo1  
new TestMethod(); 7uxPkZbb  
} q$rA-`jw  
} _q_[<{#  
点击下载更多相关资料