http断点续传简单实现（java)

/* w|o@r%Q#l  
**SiteFileFetch.java 0U*"OSpF  
*/ PQ1NQy8  
package NetFox; bK1`a{  
import java.io.*; s9bP6N!,  
import java.net.*; U7eQ-r  
R_&z2I  
8|Y^Jn\p5u  
public class SiteFileFetch extends Thread { W3rvKqdw5  
Cjk AQ(9  
;<<IXXKU
 
SiteInfoBean siteInfoBean = null; //文件信息Bean S$On$]~\"  
long[] nStartPos; //开始位置 }PL  
long[] nEndPos; //结束位置 Tic9ri  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6&0a?Xu  
long nFileLength; //文件长度 J vsB^F.4  
boolean bFirst = true; //是否第一次取文件 ]m>MB )9  
boolean bStop = false; //停止标志 N<(`+?  
File tmpFile; //文件下载的临时信息 Y,\mrW}K  
DataOutputStream output; //输出到文件的输出流 (UXB#I~  
(Fd4Gw<sq  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） io3'h:+9s  
public SiteFileFetch(SiteInfoBean bean) throws IOException l'\b(3JF  
{ }rZ=j6Z  
siteInfoBean = bean; p<19 Jw<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w!7/;VJ3d  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dS=,. }  
if(tmpFile.exists ()) |c/rHEZ  
{ LXV6Ew5E  
bFirst = false; =ApT#*D)o  
read_nPos(); FQ)Ekss~C  
} ".<p R} qp  
else e'&{KD,-T  
{ rP4@K%F9jB  
nStartPos = new long[bean.getNSplitter()]; n_meJm.  
nEndPos = new long[bean.getNSplitter()]; BZshTP[`  
} 5xUPqW%3  
wJkkc9Rh'(  
2]ljm]\l  
)^sfEYoA  
} u;g}N'"  
oP 0j>i,"&  

)~(_[='  
public void run() HI 61rXNF  
{ 7HFO-r118  
//获得文件长度 V'/%)oU\"  
//分割文件 kyB]fmS  
//实例FileSplitterFetch p~ItHwiT  
//启动FileSplitterFetch线程 c'R|Wyf  
//等待子线程返回 v4aGL<SO  
try{ {'kL]qLg  
if(bFirst) pBkPn+@  
{ =^vUb  
nFileLength = getFileSize(); 3)\qts5  
if(nFileLength == -1) _4Pi>  
{ RUu'9#fq  
System.err.println("File Length is not known!"); c= uORt>  
} mH .I!  
else if(nFileLength == -2) +8I0.,'  
{ }3lF;k(2g  
System.err.println("File is not access!"); 7yl'!uz)9  
} 92Iv'(1ba  
else blv6  
{ f}eVfAf
 
for(int i=0;i<nStartPos.length;i++) B.#0kjA}  
{ Z5A<TC/:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w2[
R&hJ  
} 74#@F{w  
for(int i=0;i<nEndPos.length-1;i++) Lp=B? H  
{ Qpq0j^\  
nEndPos = nStartPos[i+1]; ^XVa!s,d  
} $*R9LPpk+  
nEndPos[nEndPos.length-1] = nFileLength; EMbsKG  
} [y>.)BU  
} Cj9Tj'0@I+  
XZGyhX7  
BW 7[JD  
//启动子线程 S:s^si2/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; pE N`&'4  
for(int i=0;i<nStartPos.length;i++) H(s^le:!  
{ o+&sodt|`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Qafg/JU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), b87o6"j  
nStartPos,nEndPos,i); +\chHOsw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C@i
g3fhV  
fileSplitterFetch.start(); s2WB4Uk  
} ps{(UYM=b  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qcF{Kex"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r_m&Jl@4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [:qX3"B  
nEndPos = " + nFileLength); jo~vOu  
// fileSplitterFetch[nPos.length-1].start(); ?dYDfyFfB  
ntejFy9_  
v( B4Bz2  
//等待子线程结束 .O^|MhBJu  
//int count = 0; 0 CS_-  
//是否结束while循环 j;.&+.  
boolean breakWhile = false; a\MJbBXv  
:e;fs.C  
I<U 1V<g  
while(!bStop) ):@B1 yR  
{ psVRdluS   
write_nPos(); -(EqBr@_  
Utility.sleep(500); :JYOC+#q7  
breakWhile = true; {Xj%JE[V  
T9A5L"-6T  
qDW/8b\^  
for(int i=0;i<nStartPos.length;i++) edQ><lz  
{ jG#sVK]  
if(!fileSplitterFetch.bDownOver) y6oDbwke  
{ i747( ^  
breakWhile = false; Jo@9f(hq  
break; rIb{=';  
} :.,I4>b2  
} b+>godTi_  
if(breakWhile) a=R-F!P)  
break; ;D:v@I$I  
0% /M& N  
"oQ@.]-#  
//count++; RZZB?vx  
//if(count>4) P}jr 8Z  
// siteStop(); eu=2a>  
} K2QD&!4/T2  
53QP~[F8R]  
:`K;0`C+  
System.err.println("文件下载结束！"); ?)&TewP  
} vKe
K]  
catch(Exception e){e.printStackTrace ();} 7^F?key?  
} /<@tbZJ*8  
>+r2I%  
vhC"f*  
//获得文件长度 tdm /U  
public long getFileSize() VbjFQ@[l!  
{ M<nn+vy`  
int nFileLength = -1; ~xCy(dL^}  
try{ fu/c)D6u*m  
URL url = new URL(siteInfoBean.getSSiteURL()); 0Ju{6x(|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >Vvc55z  
httpConnection.setRequestProperty("User-Agent","NetFox"); JpDkf$kM  
! [X<
>  
`xSXGI  
int responseCode=httpConnection.getResponseCode(); 0/Csc\Xl  
if(responseCode>=400) cQny)2k*x  
{ I zT%Kq  
processErrorCode(responseCode); k8TMdWW  
return -2; //-2 represent access is error >&R|t_ypw  
} yWuq/J:  
s5.2gu|"%  
QS_u<B
 
String sHeader; o,-@vp  
"O4Z).5q3  

JF7T1T  
for(int i=1;;i++) +vP1DXtj(  
{ w%ForDB>P  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); epnDvz\  
//Utility.log(in.readLine()); O
tr@jgw  
sHeader=httpConnection.getHeaderFieldKey(i); ]q j%6tz  
if(sHeader!=null) <Wd$6  
{ }\W3a_,v)  
if(sHeader.equals("Content-Length")) &}]Wbk4:  
{ )JPcSy*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3Wiu`A  
break; K"#}R<k8:A  
} Ii)TCSt9U?  
} wv<"W@& 9  
else _AFgx8  
break; 7Q
`4*H6  
} pr2d}~q4{  
} AXyuXB  
catch(IOException e){e.printStackTrace ();} }IV7dKzl  
catch(Exception e){e.printStackTrace ();} cH#`f4  
=<g\B?s]  
d+(~{xK:  
Utility.log(nFileLength); Jd |hwvwFe  
WIg"m[aIs  
Xf0pQ]8\  
return nFileLength; 4&\m!s  
} L{42?d  
6V)#Yf  
gC 4w&yL  
//保存下载信息（文件指针位置） 4l|Am3vzX  
private void write_nPos() _]\mh,}  
{ Kl*##qw!  
try{ |89`O^   
output = new DataOutputStream(new FileOutputStream(tmpFile)); hi37p1t   
output.writeInt(nStartPos.length); ' o5,P/6  
for(int i=0;i<nStartPos.length;i++) b;yhgdFx  
{ |peZ`O^~  
// output.writeLong(nPos); 3Ry?{m^  
output.writeLong(fileSplitterFetch.nStartPos); lY~xoHT;[  
output.writeLong(fileSplitterFetch.nEndPos); ,Zdc  
} t~Uqsa>n@'  
output.close(); Ei#"r\q j_  
} 8Hhe&B  
catch(IOException e){e.printStackTrace ();} $o
NkE  
catch(Exception e){e.printStackTrace ();} !v^D j']  
} dLAElTg  
x*YJ:t  
=$HzEzrw  
//读取保存的下载信息（文件指针位置） gAE}3//  
private void read_nPos() eC1cE  
{ X\h]N  
try{ p5*i d5
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *P_TG"^{W  
int nCount = input.readInt(); -X |G  
nStartPos = new long[nCount]; `Z{7Ut^)  
nEndPos = new long[nCount]; TPkm~>zD.  
for(int i=0;i<nStartPos.length;i++)
xT@\FwPr  
{ 4Ld0AApncy  
nStartPos = input.readLong(); ^,?]]=mE  
nEndPos = input.readLong(); [P[syi#]t  
} `+<5QtD  
input.close(); pdE=9l'  
} kJ~^ }o  
catch(IOException e){e.printStackTrace ();} )q#b^( v  
catch(Exception e){e.printStackTrace ();} %1#5 7-  
} W nVX)o  
)]/!:I4e  
~oOOCB  
private void processErrorCode(int nErrorCode)  yXDf;`J  
{ c=ZX7U  
System.err.println("Error Code : " + nErrorCode); }C)  
} s|qB;  
nOOA5Gz  
-8-Aqh8|  
//停止文件下载 GwpJxiFgk  
public void siteStop() 0.?|%;^ib  
{ w7O(I"  
bStop = true; D[U5SS!)  
for(int i=0;i<nStartPos.length;i++) /P,J);Y  
fileSplitterFetch.splitterStop(); ?bbguwo~F  
IH{g-#U  
gllXJM^ -  
} }lWEbQ)(!  
} -PxA~((g
5  
//负责部分文件的抓取 4).q+{#k  
**FileSplitterFetch.java BM:je(*p  
*/ o\2#o5#  
package NetFox; Fm*O&6W\@A  
s7=]!7QGS!  
+lE 9*Gs_$  
import java.io.*; yaeX-'(Fv[  
import java.net.*; L8!xn&uyP=  
Wvcj\2'yd  
R,tR{| 8  
public class FileSplitterFetch extends Thread { wWwY.}j  
KaOS!e'  
P_w+p"@m  
String sURL; //File URL w2Pkw'a{  
long nStartPos; //File Snippet Start Position K^9!Qp  
long nEndPos; //File Snippet End Position Vk[m$  
int nThreadID; //Thread's ID :U?Kwv8s  
boolean bDownOver = false; //Downing is over Q~uj:A]n<  
boolean bStop = false; //Stop identical m%m8002  
FileAccessI fileAccessI = null; //File Access interface H]YPMG<  
]{dg"J  
KO:o GUR  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h4ZrD:D0\  
{ VTD'D+t  
this.sURL = sURL; m\j'7mZ1  
this.nStartPos = nStart; H+-9R  
this.nEndPos = nEnd; 8W#whK2El  
nThreadID = id; BLfoU_Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J5I
Q  
} n;4`IK|  
eja_+`cJ  
voCQ_~*)9  
public void run() DN!:Rm uc  
{ YwEXTy>0  
while(nStartPos < nEndPos && !bStop) )x#^fN~ 7`  
{ Zs)HzOP)9  
kyz_r6  
)j!22tlL  
try{ Nf
Ki,^O  
URL url = new URL(sURL); ]*Zg(YA
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jF{zcYU  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z&YW9de@  
String sProperty = "bytes="+nStartPos+"-"; jFnq{Lt  
httpConnection.setRequestProperty("RANGE",sProperty); 9V("K  
Utility.log(sProperty); A{Pp`*l  
<T<?7SE+  
>OmY  
InputStream input = httpConnection.getInputStream(); e<>(c7bF  
//logResponseHead(httpConnection); +ImPNwrY  
u9QvcD^'z  
.\qZkk}2l  
byte[] b = new byte[1024]; <
[kdF")  
int nRead; =((#kDrN  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ABB4(_3E  
{ G^5}T>TV  
nStartPos += fileAccessI.write(b,0,nRead); z1_\P) M  
//if(nThreadID == 1) StA5h+[m  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $ ^m_M.1  
} jbGP`b1_  
KE6[u*\  
4w\cS&X~C  
Utility.log("Thread " + nThreadID + " is over!"); 4)i/B99k  
bDownOver = true; /N]?>[<NW  
//nPos = fileAccessI.write (b,0,nRead); Tw);`&Ulo  
} 1]m]b4]  
catch(Exception e){e.printStackTrace ();} M+9G^o)u  
} Whod_Uk  
} 2t*@P"e!  
"\U$aaF  
o"J}@nF  
//打印回应的头信息 \Xh
zaM   
public void logResponseHead(HttpURLConnection con) wSBDJvI  
{ v4DF #O  
for(int i=1;;i++) ZWxq<&Cg  
{ rhsSV3iM  
String header=con.getHeaderFieldKey(i); TnCN2#BO  
if(header!=null) l+Uy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :
6./yj(  
Utility.log(header+" : "+con.getHeaderField(header)); d7qHUx'=z  
else N)WAzH  
break; &%$r3ePwc  
} 2mWW0txil  
} `)/G5 fB  
wZ5+ H%x  
|#Z:v1]"  
public void splitterStop() '/J}T -,Z  
{ ,?P@ :S<8  
bStop = true; %70sS].@  
} )E'iC
  
g,@0 ;uVq  
;3-5U&Axt  
} Re0ma%~LP  
*am.NH\  
F$N"&<[c  
/* Wf +j/RxTi  
**FileAccess.java bO^#RVH  
*//文件访问(定位，写) 5VDqx@(  
package NetFox; pc J5UJY  
import java.io.*; pZ}4'GnZI  
eR4%4gW)  
_ko16wfg  
public class FileAccessI implements Serializable{ +'Ec)7m  
}E+#*R3auB  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K1AI:$H  
RandomAccessFile oSavedFile; $z)r(N$  
long nPos; qCi6kEr  
%(79;#2`  
g@BQ!}_#5  
public FileAccessI() throws IOException J*vy-[w  
{ |$`)d87,  
this("",0); l\vtz5L  
} Py3Xvudv  
A
]id*RtY  
: " 9F.U  
public FileAccessI(String sName,long nPos) throws IOException ]L@VpHEj  
{ -^`]tF`M  
oSavedFile = new RandomAccessFile(sName,"rw"); ,|,DXw  
this.nPos = nPos; uW3`gwwlU  
oSavedFile.seek(nPos); 3Sv<Viuo  
} &'uFy0d,  
,A T!:&<X  
NguJ[  
public synchronized int write(byte[] b,int nStart,int nLen) 0'{0kE[wn  
{ /f@VRME  
int n = -1; nw){}g  
try{ l*T>9yC  
oSavedFile.write(b,nStart,nLen); ]([:"j  
n = nLen; E5(\/;[*`  
} z=J%-Hq>  
catch(IOException e) =\GuIH2  
{ 0!!b(X(  
e.printStackTrace (); (vMC.y5  
} 0wU8PZ Nj  
$@<qaR{t\  
8.3888  
return n; B#9rqC  
} Z[[ou?c  
-]\cUQ0  
(\}>+qS[  
} ^|M\vO  
TO7%TW{L  
Yj99[ c#]  
/* z;yb;),  
**SiteInfoBean.java !r]
elX  
*/ }>Gnpc  
package NetFox; P~$FgAV  
:oh(M|;/2  
u4*7n-(  
public class SiteInfoBean { l3dGe'  
RG1~)5AL~Y  
;gfY_MXnF  
private String sSiteURL; //Site's URL JDrh-6Zgj  
private String sFilePath; //Saved File's Path RLBjl%Q>  
private String sFileName; //Saved File's Name PYX]ld.E  
private int nSplitter; //Count of Splited Downloading File m22M[L(q  
28J ;9  
4)./d2/E  
public SiteInfoBean() x;ym_UZ6e  
{//nSplitter的缺省值为5 H7bdL 8/  
//default value of nSplitter is 5 iTJSW  
this("","","",5); t>p!qKrE'J  
} g"gh2#!D  
iLiEh2%P  
teh$W<C  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jsL\{I^>  
{ HL-zuZa`Ju  
sSiteURL= sURL; 9N5ptdP.d  
sFilePath = sPath; gU1E6V-Jm  
sFileName = sName; -S5M>W.Qb{  
this.nSplitter = nSpiltter; vX|ZPn#  
# ~SuL3  
HH =sq  
} |_ZD[v S  
J`}5bnFP  
ZS[(r-)$F  
public String getSSiteURL() k9H7(nS{  
{ JbN@AX:%  
return sSiteURL; ~"F83+RDe  
} CMn&1  
|d}f\a`  
NfqJ>[}I+  
public void setSSiteURL(String value)
GjlA\R^e  
{ P[{qp8(g  
sSiteURL = value; ns`|G;1vv  
} oo sbf#V  
/c
/t_xB  
Y Y4"r\V  
public String getSFilePath() E=!=4"rZF  
{ @*SgeLeL  
return sFilePath; +mP&B<=H)  
} am;)@<8~Q  
%%
J)@k^vH  
Z
'sAu#C  
public void setSFilePath(String value) pGEYke NU  
{ ,Y 1&[  
sFilePath = value; h#a;(F4_7  
} pUtd_8  
*PQu9>1w  
OL+dx`Y  
public String getSFileName() 0IU>KGJ-0s  
{ PAG.],"D  
return sFileName; 0?kaXD  
} GQ<]Sd}
[  
h&Thq52R  
|tL57Wu93  
public void setSFileName(String value) tj:3R$a  
{ H}G=%j0  
sFileName = value; =*EIe z*.x  
} 242dT/j  
*xm(K+j  
*=UxX ]0y  
public int getNSplitter() Pp-\#WJ  
{ ie4keVlXc  
return nSplitter; f4.k%|
]  
} lR]z8&  
g$C-G5/bjD  

D5
]4(]k&  
public void setNSplitter(int nCount) a(}dF?M=  
{ 4u}"ng   
nSplitter = nCount; |GPR3%9  
} 27mGX\T  
} 7w}D2|+  
x:'M\c7  
~3k& =3d]  
/* jIY   
**Utility.java V=yRE  
*/ gp07I{0~m  
package NetFox; 2kg<O%KA`c  
:|hFpLt  
+B^(,qKMN  
public class Utility { ]L0GIVIE  
@oC# k<  
}6/L5j:+  
public Utility() ?v-Y1j  
{ jG($:>3a@  
dD6I @N)X  
_isqk~ ul  
} TMt,\gTd  
Nxk3uF^  
//线程睡眠 4o,%}bo&  
public static void sleep(int nSecond) >:W7f2%8`  
{ a[TR_uR  
try{ $Pa7B]A,Ae  
Thread.sleep(nSecond); uK6_HvHuy  
} 3f'dBn5  
catch(Exception e) 3$Ecq|4J:  
{ .Q'/e>0  
e.printStackTrace (); Wxjv=#3  
} en\shc{R]`  
} :00 #l]g0q  
]RYk Y7>`  
//日志 nya-Io.  
public static void log(String sMsg) X4<!E#  
{ U?/UW;k[  
System.err.println(sMsg); (hywT)#+  
} -[-LR }u  
|Ad1/>8i  
piIr.]  
public static void log(int sMsg) c&zZsJ"~  
{ !]bXHT&!R  
System.err.println(sMsg); "=~P&Mi_  
} Fy4jujP<  
} -fF1vJ7L  
r()%s3$q  
|||uTfrJ  
/* ]TTX<R ZLr  
**TestMethod.java F8*e  
*/ _
ED,DM  
package NetFox; **\BP,]}  
i!zh9,i>M  
L||_
Jsu  
public class TestMethod { ZLA&<]Ad"$  
6;/>asf  
ciKkazx
.  
public TestMethod() \Ol3kx|  
{ ///xx/weblogic60b2_win.exe |7IlYy&:  
try{ 8J|pj4ce  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); CbK&.a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); F|._'i+B!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); GH%'YY3|  
fileFetch.start(); (W~jr-O^  
} W#cr9"'Ta  
catch(Exception e){e.printStackTrace ();} `Pj7O/!)#!  
p%304oP6  
Y.$InQ gL  
} J"w!Q\_  
]h (TZu  
u7|{~D&f  
public static void main(String[] args) c"ukV_6~J  
{ 75Xi%mlE7  
new TestMethod(); XQEGMaZ  
} |xI\)VE^  
} t3 AZS0  
点击下载更多相关资料