http断点续传简单实现（java)

/* :#w+?LA*  
**SiteFileFetch.java H*{k4  
*/ :-u-hO5*8  
package NetFox; <L/M`(:=k  
import java.io.*; XK%W^a*x
 
import java.net.*; }or2 $\>m  
L+L"$  
`Ixs7{&jU  
public class SiteFileFetch extends Thread { #K#Mv/  
&#-|Yh/  
+t>*l>[  
SiteInfoBean siteInfoBean = null; //文件信息Bean UOu
6LD/|h  
long[] nStartPos; //开始位置 6c2ThtL  
long[] nEndPos; //结束位置 n4WSV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 YO(:32S  
long nFileLength; //文件长度 p584)"[*t  
boolean bFirst = true; //是否第一次取文件 nR o=J5tY  
boolean bStop = false; //停止标志 X"k^89y$  
File tmpFile; //文件下载的临时信息 'Gl;Ir^  
DataOutputStream output; //输出到文件的输出流 ?UZ$bz  
:_^0'ULP  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） cK|rrwa0  
public SiteFileFetch(SiteInfoBean bean) throws IOException wrQydI  
{ ]M~8@K  
siteInfoBean = bean; *f`s%&Y]s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i0'Xy>l  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U+.PuC[3  
if(tmpFile.exists ()) .>kccLr:z  
{ t}]9VD9  
bFirst = false; c>S"`r  
read_nPos(); "J P{Q  
} emv;m/&8  
else ,b6kTQq  
{
56Sh  
nStartPos = new long[bean.getNSplitter()]; (Bt;DM#>  
nEndPos = new long[bean.getNSplitter()]; '!
wPnYT@D  
} ^V<J69ny|9  
6%ZHP?  
H_?;h-Y]  
1UW s_|X!  
} e(}oq"'z  
k;;nE o~6
 
N<aB)</  
public void run() d&aBs++T  
{ #D`S  
//获得文件长度 *CeQY M  
//分割文件 ;Ze"<U  
//实例FileSplitterFetch |?x^8e<*  
//启动FileSplitterFetch线程 7$+P|U
 
//等待子线程返回 0W~.WkD  
try{ :%/\1$3P  
if(bFirst) W il{FcHY  
{ u}Ei_ O<z  
nFileLength = getFileSize(); c8#T:HM|`  
if(nFileLength == -1) GFdZ`i  
{ ZR/R'prW  
System.err.println("File Length is not known!"); ATMc`z:5T  
} jOBY&W0r  
else if(nFileLength == -2) hz<|W5  
{ !~K=#"T  
System.err.println("File is not access!"); \R86;9ov  
} @Pxw
hlxa  
else DH\wD
Q  
{ DUZQO{V  
for(int i=0;i<nStartPos.length;i++) !Z U_,[  
{ "?i>p z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5U0ytDZ2/(  
} '"` Lv/  
for(int i=0;i<nEndPos.length-1;i++) 968Ac}OA  
{ 4)c+t"h  
nEndPos = nStartPos[i+1]; IIq"e~"Vs  
} T@(6hEmP,  
nEndPos[nEndPos.length-1] = nFileLength; LKqRvPnh  
} cJP'ShnCh  
} `aO.=:O_  
>65 TkAp  
X$BXT  
//启动子线程 `Uzs+k-]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rW:iBq  
for(int i=0;i<nStartPos.length;i++) Ab*]dn`z  
{ ]@*tfz\YaH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GS}0;x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), so}l#  
nStartPos,nEndPos,i);  ;e&
!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wX-RQ[2X  
fileSplitterFetch.start(); myD{sE2A  
} dKU5;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mYX56,b}5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j: <t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", q^u1z|'Z  
nEndPos = " + nFileLength); Lb!r(o>8Cb  
// fileSplitterFetch[nPos.length-1].start(); dO+kPC  
7k3p'FeS  
HKpD2M  
//等待子线程结束 PdR >;$1  
//int count = 0; Qqp)@uM^  
//是否结束while循环 PT mf  
boolean breakWhile = false; >P(eW7RL  
-<O JqB  
)j\r,9<K+5  
while(!bStop) 9#u}^t  
{ ?^U c=  
write_nPos(); w]n4KR4  
Utility.sleep(500); ]X*YAPv  
breakWhile = true; #xlZU  
y0;,dv]  

8,=G1c  
for(int i=0;i<nStartPos.length;i++) (%i!%{!]  
{ DK)u)?!  
if(!fileSplitterFetch.bDownOver) Fl<
(m  
{ K~USK?Q%  
breakWhile = false; 1x{XE*%;  
break; Mz93  
} _O$tuC%  
} %Hh3u$Y,  
if(breakWhile) o5>/}wIf  
break; }gCG&7C  
U%L -NMe  
vsH3{:&;"P  
//count++;  ?J<T  
//if(count>4) :H{Bb{B%  
// siteStop(); _ ~|Q4AJ  
} {-Yee[d<
?  
4*iHw+%mq  
9-b 8`|s  
System.err.println("文件下载结束！"); R^w}o,/  
} $cq!RgRn  
catch(Exception e){e.printStackTrace ();} 7iP5T  
} }0Y`|H\v  
NJ<N%hcjK  
`y'aH 'EEd  
//获得文件长度 ?<E0zM+  
public long getFileSize() :aH%bk  
{ MZ)T0|S_  
int nFileLength = -1; (X*9w##x(  
try{ E&'#=K[  
URL url = new URL(siteInfoBean.getSSiteURL()); W
;.{]x.0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .`Sw,XL5  
httpConnection.setRequestProperty("User-Agent","NetFox"); :xM}gPj"  
ANotUty;y  
u-kZW1wrQ  
int responseCode=httpConnection.getResponseCode(); ~*,Wj?~+7  
if(responseCode>=400) 7g5@vYS+  
{ zb>;?et;)  
processErrorCode(responseCode); s*f1x N<  
return -2; //-2 represent access is error qT$)Rb&  
} Y5n>r@)m  
J=@x
AVBc  
|f<9miNu  
String sHeader; _@
~PL>g"p  

f -7S:,  
S4)A6z$  
for(int i=1;;i++) nz[ m3]  
{ zMr&1*CDX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h<)yJh  
//Utility.log(in.readLine()); )&Mq,@  
sHeader=httpConnection.getHeaderFieldKey(i); !j{CuA/  
if(sHeader!=null) iyc$)"w  
{ O)`Gzx*ShU  
if(sHeader.equals("Content-Length")) s047"Q  
{ LaclC]yLU  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \KCWYi]  
break; lr0M<5d=p  
} YIO.yN"0  
} '^DUq?E4  
else '=p?  
break; BR3wX4i\  
} ?]5Ix1  
} (V!0'9c  
catch(IOException e){e.printStackTrace ();} J B(<.E2  
catch(Exception e){e.printStackTrace ();} 5~QTg  
1)'Iu`k/  
{U^j&E  
Utility.log(nFileLength); <W2ZoqaV  
Gp8psH  
e:BDQU  
return nFileLength; /~tP7<7A  
} a>w~FUm*  
@gEr+O1K(  
xvB8YW"  
//保存下载信息（文件指针位置） q=+wI"[  
private void write_nPos() n_}aZB3;U  
{ %XR<isn  
try{ ~TM>"eBb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Mb1wYh  
output.writeInt(nStartPos.length); WU7cF81$  
for(int i=0;i<nStartPos.length;i++) 5/,Qz>QE[  
{ c@9##DPn  
// output.writeLong(nPos);
Ok,HD7  
output.writeLong(fileSplitterFetch.nStartPos); (Igu:=  
output.writeLong(fileSplitterFetch.nEndPos);
#n#HzbT  
} >x*)GPDa  
output.close(); 9>;} /*:H  
} ZL,8,;]  
catch(IOException e){e.printStackTrace ();} a MsJO*;>  
catch(Exception e){e.printStackTrace ();} 3Soy3Xp  
} y] y9'5_  
%0zS  
'gCZ'edM  
//读取保存的下载信息（文件指针位置） 6uqUiRs()  
private void read_nPos() HD H  
{ ##GY<\",;  
try{ {m'AY)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p(?g-
  
int nCount = input.readInt(); vzG ABP  
nStartPos = new long[nCount]; e,"FnW  
nEndPos = new long[nCount]; {:$NfW  
for(int i=0;i<nStartPos.length;i++) XfDX:b1p  
{ M9DgO4xl  
nStartPos = input.readLong(); ?M~  k$  
nEndPos = input.readLong(); 0#^Bf[Dn  
} ,Y-S
(  
input.close(); [4: Yi{>  
} #QS?s8IrW  
catch(IOException e){e.printStackTrace ();} C99&L3bz^(  
catch(Exception e){e.printStackTrace ();} -x5F;d}  
} |Qr:!MA  
FB_NkXR  
dXK-&Po'  
private void processErrorCode(int nErrorCode) @h9K  
{ d>/Tu_ y  
System.err.println("Error Code : " + nErrorCode); .6Fsw   
} fM2^MUp[=1  
TRy^hr8~  
Fpf><Rn  
//停止文件下载 G AEZY

 
public void siteStop() {Zl4C;c  
{ h7*O.Opm=  
bStop = true; +99Bi2H}o  
for(int i=0;i<nStartPos.length;i++) QtlT&|$   
fileSplitterFetch.splitterStop(); *uU4^E(  
}1@E"6kF  
^cn@?k((A  
} _A3X6  
} @ZG>mP1Vo  
//负责部分文件的抓取 6KO(j/Gwp  
**FileSplitterFetch.java s??czM2O  
*/ yV2e5/i  
package NetFox; [T]Bfo  
5*+I M*c  
gyFr"9';c  
import java.io.*; G B&:G V  
import java.net.*; aj v}JV&:  
tah
}^  
.1{l[[= W  
public class FileSplitterFetch extends Thread { R;'?;I  
S<pk
c8  
2vvh|?M  
String sURL; //File URL C`EY5"N r  
long nStartPos; //File Snippet Start Position 
P5P<"  
long nEndPos; //File Snippet End Position tR;{.  
int nThreadID; //Thread's ID q5?{1  
boolean bDownOver = false; //Downing is over gwq`_/d}  
boolean bStop = false; //Stop identical }hq^+fC?  
FileAccessI fileAccessI = null; //File Access interface Y/D-V  
HU9p!I.  
C=[A
e,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~1ps7[  
{ U{HML|  
this.sURL = sURL; xW0Z'==  
this.nStartPos = nStart; ^/<|f,2  
this.nEndPos = nEnd; )#PtV~64  
nThreadID = id; =y<0UU  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Gnv!]c&S>l  
} e96#2A5f  
[zx|eG<&-  
X Ny Y$  
public void run() ZRPy~wy>  
{ j.B>v\b_3  
while(nStartPos < nEndPos && !bStop) f~R[&q+  
{ A_i zSzC1  
bBG/gQ  
*v&*% B  
try{ }H2#H7!H  
URL url = new URL(sURL); l?<q YjI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +`Fb_m)f  
httpConnection.setRequestProperty("User-Agent","NetFox"); P9s_2KOF  
String sProperty = "bytes="+nStartPos+"-"; 'e85s%ru  
httpConnection.setRequestProperty("RANGE",sProperty); q<EEb  
Utility.log(sProperty); gb(#DbI  
Bj8<@~bX:L  
+(y>qd  
InputStream input = httpConnection.getInputStream(); _Fxe|"<^  
//logResponseHead(httpConnection); 03F3q4"  
C]Q>*=r  
+N8aq<l  
byte[] b = new byte[1024]; _aY.  
int nRead; o X@nP?\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) N3Z@cp  
{ yf?W^{^|  
nStartPos += fileAccessI.write(b,0,nRead); qCQu^S' iD  
//if(nThreadID == 1) I{EIHD<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?b"Vj+1:x  
} + ~~ Z0.[  
4&]%e6,jH  
iJ4<f->t  
Utility.log("Thread " + nThreadID + " is over!"); %Co b(C&}  
bDownOver = true; }k| g%HJ  
//nPos = fileAccessI.write (b,0,nRead); sjb-Me?  
} VfRs[3
Q  
catch(Exception e){e.printStackTrace ();} phmVkV2a;#  
} P#v^"}.Wd  
} "f<#.}8  
=1IEpxh%  
?yf_Dt  
//打印回应的头信息 B>@D,)/bT5  
public void logResponseHead(HttpURLConnection con) 9?(x>P  
{ T\fudmj&  
for(int i=1;;i++) ,H@
TYw  
{ b*`fLrqV.  
String header=con.getHeaderFieldKey(i); CC>($k"  
if(header!=null) L&QtHSzy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); CWBbSGk  
Utility.log(header+" : "+con.getHeaderField(header)); ?R282l  
else {Hr>X  
break; U&X.
 
} H4 =IY  
} U1jSUkqb  
I:HV6_/^-G  
$YPQC  
public void splitterStop() PF`:1;PU  
{ m|mG;8}pI  
bStop = true; hwp/jO:7\  
} "h$D7 mL  
xY+A]Up|w  
3<3t;&e  
} @BXaA0F4  
Kn.iyR  
{o {#]fbO%  
/*
|veBq0U  
**FileAccess.java t"tNtLI  
*//文件访问(定位，写) q 7`  
package NetFox; B6uf;Yc  
import java.io.*; 9!c
W  
3}yraX6r!  
h~ZNHSP:  
public class FileAccessI implements Serializable{ "~Us#4>  
0OEtU5lf`y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7F~xq#Wi#  
RandomAccessFile oSavedFile; j~.u>4  
long nPos; jWh
D5k@v  
yG4MUf6  
F; 0Dp
 
public FileAccessI() throws IOException #|q;t   
{ .N&QW `  
this("",0); /%;/pi  
} $sM]BE:  
L^&do98  
4">84,-N  
public FileAccessI(String sName,long nPos) throws IOException N*? WUn9]  
{ CO7CNN  
oSavedFile = new RandomAccessFile(sName,"rw"); )|Jr|8  
this.nPos = nPos; ,znL,%s  
oSavedFile.seek(nPos); gl Li  
} > d^r">!,  
 eMztjN  
1/!nV  
public synchronized int write(byte[] b,int nStart,int nLen) Qve`k<Cj"  
{ K:C+/O  
int n = -1; b\H/-7<  
try{ /oBK&r[(  
oSavedFile.write(b,nStart,nLen); H_v/}DEG  
n = nLen; gr[D!D>  
} i;gw=Be  
catch(IOException e) -g~iE]x6Y  
{ VB}PNg  
e.printStackTrace (); YK7
gd|LR]  
} Ed4_<:  
5QNBB|X@  
O'Vh{JHf  
return n; ?NQD#  
} 6CCZda@  
+HYN$>  
+W!'B
r  
} Id; mn}+~  
RiwEuY  
[Q7`RB  
/* ;9 lqSv/6  
**SiteInfoBean.java &0?DL  
*/ H;4oZ[g  
package NetFox; uV/)Gb*j  
Uzy;#q  
*vEU}SxRuv  
public class SiteInfoBean { xtG)^x!  
$eTv6B?m  
h4B+0  
private String sSiteURL; //Site's URL <#:Ebofsn  
private String sFilePath; //Saved File's Path _Jt_2o%G  
private String sFileName; //Saved File's Name mOABZ#+Fk  
private int nSplitter; //Count of Splited Downloading File "87O4 #$  
a>#d=.  
(v9!g#  
public SiteInfoBean() 0q-0zXlSL  
{//nSplitter的缺省值为5 o<9yaQ;  
//default value of nSplitter is 5 _gis+f/8h  
this("","","",5); 2&3eAJC  
} yOn H&Jj  
5VCMpy  
bf&.rJ0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2y&_Z^kI?  
{ ;F" kD  
sSiteURL= sURL; }?\#_BCjx(  
sFilePath = sPath; sASAsGk<  
sFileName = sName;
dfYYyE  
this.nSplitter = nSpiltter; AycA:<  
Y0R\u\b  
1)nM#@%](h  
} k 2 mkOb  
'` BjRg57]  

E,"b*l.  
public String getSSiteURL() :..E:HdYO  
{ ljaAB+  
return sSiteURL; UtHmM,*I  
} AIIBd  
!xJLeQFJI]  
!;BZ#tF&  
public void setSSiteURL(String value) |:J*>"sq  
{ <lsi.x\y<  
sSiteURL = value; rF <iWM=  
} 6z%&A]6k:  
N?Z+zN&P  
A,-[/Z K/  
public String getSFilePath() %FXIlH
5
 
{ 2`q^Q  
return sFilePath; 7N-CtQnv  
} *)}Ap4[  
=N[V{2}q  
(9'G  
public void setSFilePath(String value) o}j_eHl{  
{ HZ[68T[8b  
sFilePath = value; %Hh &u .  
} < |]i  
Cv?<}q  
+qu@dU0\`|  
public String getSFileName() x _YV{  
{ 9/8@  
return sFileName; J%O[@jX1  
} NoSqzJyh  
W}<M?b4tP  
"OlI-^y  
public void setSFileName(String value) ys~p(  
{ NUxAv= xl  
sFileName = value; tOlzOBzR  
} &})4?5  
}(vOaD|k=  
hCOy\[2$  
public int getNSplitter() R+@sHsZ@  
{ 4IGQ,RTB  
return nSplitter; gzJ{Gau{)  
} 7kWZMi  
hoSU`X  
}y-AoG  
public void setNSplitter(int nCount) 4,R\3`b  
{ s1*WK&@  
nSplitter = nCount; D; 35@gtj  
} \e5,`  
} $HR(|{piZ  
(0+GLI8  
OA8b_k~  
/* l,FG:"`Z@  
**Utility.java SjNwT[.nr7  
*/ G+\~rl  
package NetFox; !]jNVg  
r)Mx.`d!  
3<1HqU  
public class Utility { R;Ix<y{U  
Hhce:E@K  
C>(
M+qXL+  
public Utility() *Tlws  
{ /n<Ncf  
9O0  

O}\"$n>  
} jW+VU
F-t  
}1^tK(Am  
//线程睡眠 ?6l,   
public static void sleep(int nSecond) VHXR)}  
{ R~seUW7uv"  
try{ _QtQPK\+  
Thread.sleep(nSecond); s'fcAh,c6  
} ,a?\i JNb  
catch(Exception e) q}76aa0e  
{ E)Zd{9A5)  
e.printStackTrace (); uvK%d\d  
} ]P ?#lO6  
} ;r@R (Squ  
bUg2Bm!y  
//日志 +Muia5G  
public static void log(String sMsg) y[7xK}`_  
{ dQ2i{A"BKz  
System.err.println(sMsg); Sr#fyr  
} iJp!ROI  
t BXsWY{  
Ivgwm6M  
public static void log(int sMsg) V44sNi  
{ J Wyoh|  
System.err.println(sMsg); P A+e= %  
} HDXjH|of  
} gV.Pg[[1  
4>ce,*B1  
]V]@Zna@g  
/* ~6kA<(x  
**TestMethod.java
pQm!Bt L  
*/ #L*@~M^]  
package NetFox; %cjGeS6}  
BrH`:Dw  
}Us
$y0W\  
public class TestMethod { @snLE?g j  
x`|tT%q@l  
]e3}9.  
public TestMethod() uC8T!z  
{ ///xx/weblogic60b2_win.exe 0Ukl#6  
try{ (j8,n<o  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Q8/0Cb/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D@vvy6
>~s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ';L^mxh  
fileFetch.start(); L
yPBFo[?  
} ?Dp^dR  
catch(Exception e){e.printStackTrace ();} |h~/Zz=  
RlPByG5K  
co%_~xO  
} arH\QPaka'  
J,M5<s[Xqt  
oP`M\KXau  
public static void main(String[] args) Xs,PT  
{ F>-@LOqHy  
new TestMethod(); T|iF/p]F  
} u#k6v\/  
} }
c#/1J7  
点击下载更多相关资料