http断点续传简单实现（java)

/* \|gE=5!Am=  
**SiteFileFetch.java ~v$1@DQ}  
*/ 3tjF4C>h|  
package NetFox; &qjc+-r{l  
import java.io.*; ,'nd~{pX"(  
import java.net.*; 3bd(.he2u  
jGSY$nt9  
d5z=fH9  
public class SiteFileFetch extends Thread { n`Y"b&  
tpY]Mz[J  
v><c@a=[  
SiteInfoBean siteInfoBean = null; //文件信息Bean :]rb}1nLB  
long[] nStartPos; //开始位置 /TndB7l"3  
long[] nEndPos; //结束位置 [XKudw%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 t4P`#,:8  
long nFileLength; //文件长度 xk:=.Qqh  
boolean bFirst = true; //是否第一次取文件 'e(]woe  
boolean bStop = false; //停止标志 %6%~`((4  
File tmpFile; //文件下载的临时信息 Pss$[ %  
DataOutputStream output; //输出到文件的输出流 b4R;#rm  
3OlXi9>3  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） z]%c6ty  
public SiteFileFetch(SiteInfoBean bean) throws IOException mM$|cge"  
{ @7? O#WmL  
siteInfoBean = bean; @fc
-[pv  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); q^w@l   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); CQANex4&\  
if(tmpFile.exists ()) $SOFq+-T  
{ L7`=ec<  
bFirst = false; zzH^xxg  
read_nPos(); m}$7d5  
} lZr}F.7  
else w!eY)
p<  
{ {M^BY,%*  
nStartPos = new long[bean.getNSplitter()]; cp)BPg  
nEndPos = new long[bean.getNSplitter()]; */6lyODf  
} Dx5X6t9=  
+e87/\5  
@"G+kLv0  
dHsI<:T#  
} ;xl0J*r  
chE}TK  
VrIR!9%:  
public void run() ZamOYkRX  
{ N;q)r  
//获得文件长度 ) w1`<7L  
//分割文件 Iysp)  
//实例FileSplitterFetch c<a)Yqf"]  
//启动FileSplitterFetch线程 Due@'  
//等待子线程返回 }1#prQ0F  
try{ jl"su:y  
if(bFirst) ! }>CEE  
{ I !J'  
nFileLength = getFileSize(); jf^BEz5  
if(nFileLength == -1) ,gdud[&|;  
{ rQD^O4j R  
System.err.println("File Length is not known!"); OfK>-8  
} t}YT+S  
else if(nFileLength == -2) &e6!/y&  
{ <5 }  
System.err.println("File is not access!"); vk4Q2P  
} r,HIoeAKP  
else q"e]\Tb=we  
{ ~+)>D7  
for(int i=0;i<nStartPos.length;i++) nCS" l5  
{ &"?S0S>r!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); c[>xM3=e^q  
} 6Vj=SYK  
for(int i=0;i<nEndPos.length-1;i++) @GWJq 3e  
{ g.*DlD%%  
nEndPos = nStartPos[i+1]; M5kw3Jy5  
} bn%4s[CVb4  
nEndPos[nEndPos.length-1] = nFileLength; +P=IkbxAO  
} .|e8v _2J  
} #M)+sK$H%f  
]5r@`%9  
}0IeKpu5  
//启动子线程 B#G:aBCM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P?ms^  
for(int i=0;i<nStartPos.length;i++) 4Ql9VM%y  
{ b+CJRB1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lc$wjK[w[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5HaI$>h6  
nStartPos,nEndPos,i); c;Gf$9?iC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c`@";+|r  
fileSplitterFetch.start(); al"=ld(  
} L++qMRk9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [jv+Of IZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); kMx)G]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ek"Uq RY  
nEndPos = " + nFileLength); zP&D
  
// fileSplitterFetch[nPos.length-1].start(); tv_&PIu]L  
bXi!_'z$  
}P'c8$  
//等待子线程结束 v!W{j&N  
//int count = 0; klR\7+lK  
//是否结束while循环 .1+I8
qj  
boolean breakWhile = false; v5\5:b{/  
E/zclD5S  
A5T&i]  
while(!bStop) '3b'moy  
{ 5eiKMKW[  
write_nPos(); M@z_tR'3\  
Utility.sleep(500); N8iLI`  
breakWhile = true; "~mY4WVG  
2?{'(iay  
9:*[Q"v  
for(int i=0;i<nStartPos.length;i++) 6>]w1 H  
{ UqD ]@s`  
if(!fileSplitterFetch.bDownOver) aaP6zJXi  
{ zI0d  
breakWhile = false; S Rk%BJ? ~  
break; N
BL%5!'  
} H:)_;k  
} npd:aGx  
if(breakWhile) *M)M!jTv  
break; c5_/i7  
/xSFW7d1  
'55G:r39  
//count++; /J(vqYK"  
//if(count>4) wn;)La  
// siteStop(); Bf.iRh0Q5  
} "BVp37m;?  
h*R w^5,c  
{a__/I>)  
System.err.println("文件下载结束！");
!TivQB  
} Sn0kJIb }  
catch(Exception e){e.printStackTrace ();} qW`?,N)r  
} fwvwmZW  
&)jq3  
_RIlGs\.  
//获得文件长度 i),bAU!+m  
public long getFileSize() 'J$@~P  
{ 4l7 Ny\J  
int nFileLength = -1; zn>+
\  
try{ d@p#{ -  
URL url = new URL(siteInfoBean.getSSiteURL()); ZS%W/.?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1_b*j-j  
httpConnection.setRequestProperty("User-Agent","NetFox"); :}yT?LIyP  
Af\  
d@ >i=l [  
int responseCode=httpConnection.getResponseCode(); p="0Y<2l  
if(responseCode>=400) J?dLI_{<  
{ v<t?t<|J  
processErrorCode(responseCode); e_|Z&  
return -2; //-2 represent access is error 4i PVpro  
} KIcIYCBz  
Z+u.LXc|c  
qvLh7]sbK:  
String sHeader; "%)g^Atp>  
KIi:5Y  
R
*!s'R  
for(int i=1;;i++) \ @fKKb|  
{ <:Mz2Rg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); aU~?&]  
//Utility.log(in.readLine()); op\$(7<d-  
sHeader=httpConnection.getHeaderFieldKey(i);  3%bhW9H%  
if(sHeader!=null) :EAh%q  
{ 4y#XX[2Wj  
if(sHeader.equals("Content-Length")) Xi1|%  
{ `IEA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); haY]gmC  
break; b"Q8[k |d  
} YVwpqOE.=  
} Xl<iR]lda  
else 641P)  
break;
bU}v@Uk  
} l -xc*lC  
} x1?mE)
n]  
catch(IOException e){e.printStackTrace ();} t,Ka] /I  
catch(Exception e){e.printStackTrace ();} .1q}mw   
&
y}7AV  
tfN[-3)Z  
Utility.log(nFileLength); @ ?M\[qeF@  
Scx!h.\5  
'Y#'ozSQv  
return nFileLength; e6>G8d  
} e`S\-t?Z  
N[e,%heR  
:-5[0Mx=  
//保存下载信息（文件指针位置） W;yc)JB
 
private void write_nPos() I`_I^C3  
{ Y X^c}t}U  
try{ j<P;:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s~].iQJ{B  
output.writeInt(nStartPos.length); *V%"q|L8  
for(int i=0;i<nStartPos.length;i++) K6t
"98  
{ vX\9#Hj  
// output.writeLong(nPos); Z3weFbCH  
output.writeLong(fileSplitterFetch.nStartPos); gu!!}pwV9  
output.writeLong(fileSplitterFetch.nEndPos); $3PDe  
} pa1<=w  
output.close(); $TmEVC^0  
} g{Al
:}u>  
catch(IOException e){e.printStackTrace ();} y$\tqQ  
catch(Exception e){e.printStackTrace ();} 8W{M}>;[9  
} O7Jux-E1C  
=`QYy-b X  
50QDqC-]XS  
//读取保存的下载信息（文件指针位置） ,puoq{  
private void read_nPos() (0H=f6N  
{ C@6:uiT$  
try{ j(Lz& *4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t\hnnu`Pq  
int nCount = input.readInt(); W06#|8,{v  
nStartPos = new long[nCount]; Zs />_w}  
nEndPos = new long[nCount]; R\5,H!V9n  
for(int i=0;i<nStartPos.length;i++) &F uPd}F  
{ a1~|?PCbY  
nStartPos = input.readLong(); XZb=;tYo  
nEndPos = input.readLong(); o6px1C:  
} @T~XwJ~  
input.close(); < j:\;mi;  
} 12z!{k7N  
catch(IOException e){e.printStackTrace ();} oj - `G  
catch(Exception e){e.printStackTrace ();} le\-h'D  
} *,4rYb7I w  
p
E&G]ZC  
Vml 6\X  
private void processErrorCode(int nErrorCode) >)u;X  
{ D{6y^@/  
System.err.println("Error Code : " + nErrorCode); `P;r[j"  
} }bv+^#  
Qdq;C,}Ai.  
!iKW1ks  
//停止文件下载 OUi;f_
*[r  
public void siteStop() ~tA ^K  
{ 5[jcw`  
bStop = true; B18BwY  
for(int i=0;i<nStartPos.length;i++) P|<V0 Vs.  
fileSplitterFetch.splitterStop(); "00j
]e.  
P!W%KobZ7|  
7P+1W \  
} a#=d{/ab  
} Y7.+ Ma#|  
//负责部分文件的抓取 x 4+WZYv3  
**FileSplitterFetch.java |+q_kx@?l  
*/ =U3S"W %  
package NetFox; =O }^2OARo  
f%,S::%Ea  
D<6$@ZJ  
import java.io.*; K9#kdo1 2  
import java.net.*; Nn[*ox#i  
|O_JUl  
IQPu%n{0v  
public class FileSplitterFetch extends Thread { R^.PKT2E  
k~
8-Eu1  
m"n74cxS  
String sURL; //File URL hn8xs5vN  
long nStartPos; //File Snippet Start Position ,2fi`9=\  
long nEndPos; //File Snippet End Position ]ZcivnN#  
int nThreadID; //Thread's ID +Ww] %`_  
boolean bDownOver = false; //Downing is over MW7~=T  
boolean bStop = false; //Stop identical ._G,uP$  
FileAccessI fileAccessI = null; //File Access interface -`PziGl@<  
^YLC{V  
o99ExQ.  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,%TBW,>  
{ vTK%4=|1}!  
this.sURL = sURL; <a"(B*bBd  
this.nStartPos = nStart; U3{<+vSR`  
this.nEndPos = nEnd; Z<i}XCE  
nThreadID = id; &u2;S?7m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,p d-hu  
} GQtNk<?$I  
i!%bz  
tn5%zJ#+  
public void run() $xWwI(SaB  
{ ]3O&8,  
while(nStartPos < nEndPos && !bStop) /*qRbN  
{ TmG)
;B}  
7%Y`j/  
2t\0vV2)/O  
try{ e]RzvWq  
URL url = new URL(sURL); a<<4gXx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]@#9B>v=  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^v;)6a2  
String sProperty = "bytes="+nStartPos+"-"; Y)1/fEM  
httpConnection.setRequestProperty("RANGE",sProperty); `j>5W<5q\  
Utility.log(sProperty); ^cYB.oeu  
%
]4Tff  
;;,7Jon2  
InputStream input = httpConnection.getInputStream(); EB[T 5{  
//logResponseHead(httpConnection); N(7XILC  
_eKO:Y[e  
pN[WYM?[  
byte[] b = new byte[1024]; 9r?Z'~,Za  
int nRead; bTum|GWf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) VmqJMU>.  
{ qdix@@  
nStartPos += fileAccessI.write(b,0,nRead); l(Rn=
?  
//if(nThreadID == 1) uyWheR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b(0<,r8  
} .$&^yp  
G,)zn9X  
ai_ve[A  
Utility.log("Thread " + nThreadID + " is over!"); Pf[E..HF*d  
bDownOver = true; Ol>q(-ea  
//nPos = fileAccessI.write (b,0,nRead); KW .4 9  
} 1p}Wj*mc  
catch(Exception e){e.printStackTrace ();} 5%I3eL%s  
} $,}jz.R@  
} R(wUu#n$  
OXEEpoU?V  
^lHy)!&A  
//打印回应的头信息 <o%T]  
public void logResponseHead(HttpURLConnection con) t8*Jdd^3Z/  
{ UGO#o`.G}  
for(int i=1;;i++) 8gS7$ EH'  
{ 8FuxN2  
String header=con.getHeaderFieldKey(i); zS%XmS\  
if(header!=null) T?7u [D[[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *BsK6iVb  
Utility.log(header+" : "+con.getHeaderField(header)); Ixa0;nxj  
else 1[!:|=
 
break; g6,DBkv2  
} |[.-pA^  
} 8%9 C<+.R  
3k1e  
dVbFMQ&  
public void splitterStop() 1@|+l!rYF  
{ j.q}OK  
bStop = true; AQ'%}(#0  
} I){4MoH.  
,Pa*; o\  
J'%i?cuV  
} O <Rh[Aqn  
`==l
2AX  
yD3}USw  
/* U ]<l-~|  
**FileAccess.java y\skke]  
*//文件访问(定位，写) "8f4s|@3  
package NetFox; P6v ANL-B  
import java.io.*; {M**a  
1&dtq,|N  
,CqWm9  
public class FileAccessI implements Serializable{ "`% ,l|D  
[M\ an6h6O  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3x[Cpg,  
RandomAccessFile oSavedFile; t7]j6>MK3q  
long nPos; F rckA  
&
P-8_I  
/*#o1W?wQZ  
public FileAccessI() throws IOException ;5tOQ&p%v  
{ Jq/itsg  
this("",0); 2^o7^S  
} g{'f%bkG  
L8`v  
 >. K  
public FileAccessI(String sName,long nPos) throws IOException >5FTBe[D  
{ MfL7|b)  
oSavedFile = new RandomAccessFile(sName,"rw"); ~Gfytn9x.;  
this.nPos = nPos; MltO.K!  
oSavedFile.seek(nPos); \W*L9azr  
} t%}<S~"  
R;OPY?EeW  
H!IVbL`a{  
public synchronized int write(byte[] b,int nStart,int nLen) 9#z$GO|
<  
{ q<:8{Y|  
int n = -1; q A .9X4NQ  
try{ b? ); D  
oSavedFile.write(b,nStart,nLen); ]RT  
n = nLen; s47R,K$  
} wKM9fs  
catch(IOException e) =|?`5!A  
{ P73GH  
e.printStackTrace (); qX@e+&4P0  
} 99=~vNn  
NH/A`Wm  
KfiSQ!{  
return n; ?#z$(upQ  
} Py;5z  
6}6Q:V|  
Q a (Sb  
} +?*;#=q  
'ZF6Z9  
LzU'6ah';5  
/* !yd B,S  
**SiteInfoBean.java d0>U-.  
*/ ce;7  
package NetFox; lx|Aw@C3~  
R%jOgZG  
[D~]  
public class SiteInfoBean { j}uL  
I-R7+o  
-qP)L;n  
private String sSiteURL; //Site's URL <e UsMo<  
private String sFilePath; //Saved File's Path H7+"BWc  
private String sFileName; //Saved File's Name nqy
*>X`  
private int nSplitter; //Count of Splited Downloading File :BPgDLL,  
kPX+n+$  
`H! (hMMV  
public SiteInfoBean() ?,pwYT0g  
{//nSplitter的缺省值为5 NTu|cX\R  
//default value of nSplitter is 5 j=O+U_w  
this("","","",5); T1d@=&0
"  
} v
Fk@  
sBadiDG~9  
Jx+6Kq(  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9Vt ^q%DC  
{ 3'uXU<W!  
sSiteURL= sURL; pbx*Y`v  
sFilePath = sPath; pq) =  
sFileName = sName; .) Ej#mk  
this.nSplitter = nSpiltter; k?fz @H8D(  
j#//U2VdN  
A]bQUWt2  
} %tVU Rj  
(,I:m[0  

21v--wZ  
public String getSSiteURL() 4!/QB6   
{ 76w[X=Fv  
return sSiteURL; TDo)8+.2z  
} Y(Qb)>K  
S(PV*e8  
<W0(!<U  
public void setSSiteURL(String value) ??/bI~Sd  
{ zx$YNjeV  
sSiteURL = value; b\"F6TF:  
} M+&~sX*a  
RnH?95n?{  
Xe);LhDC  
public String getSFilePath() Y~}MfRE3z  
{ %r[`HF>  
return sFilePath; O&7.Ry m  
} ;{I9S'  
@}q, ';H7  
g@'XmT="_  
public void setSFilePath(String value) 0cmd +`  
{ /l7 %x.  
sFilePath = value; 4#(/{6J  
} OL\-SQ&  
?6_]^:s  
&oMEz 0  
public String getSFileName() i431mpMa  
{ T:Cq}4k<  
return sFileName; &oG>Rqkm  
} Qf_N,Bq{a  
X`g<"Ka  
(1CP]5W  
public void setSFileName(String value) 4XAB_Q  
{ j55_wx@cA  
sFileName = value; $s_k/dM~&  
} VrW]|jIu*  
]|3hK/  
Cj>HMB}  
public int getNSplitter() Zz} o t  
{ &n1Vv_Lb  
return nSplitter; Kl.*Q  
} G `|7NL   
__}SHU0R  
$ #!oejLD  
public void setNSplitter(int nCount) gOg7:VPG  
{ ]C^ #)
7  
nSplitter = nCount; I;@q`Tm  
} mPA)G,^  
} GSRf/::I}4  
!P
Ig,  
q;
9X8 _  
/* p.:|Z-W$  
**Utility.java RZxh"lIo  
*/ a?W5~?\9  
package NetFox; eztK`_n  
+^9^)Ur|  
)Cdw_Yx  
public class Utility { L!JC)p.  
Pjh;;k|V  
BZ\="N#f  
public Utility() KOg,V_(I  
{ o135Xh$_>'  
i5r<CxS  
rTR$\ [C  
} \Hb!<mrp  
;I5P<7VW  
//线程睡眠 -+){;,  
public static void sleep(int nSecond) {EZR}N  
{ +\+j/sa  
try{ NzZ(Nz5  
Thread.sleep(nSecond); p{oz}}  
} ;X+0,K3c  
catch(Exception e) oJM;CN  
{ MZ%J ]
Nd  
e.printStackTrace (); i@:^b_  
} 1R_@C.I  
} w&IYCYK_  
P:g!~&Q  
//日志 Q7u|^Gu,5  
public static void log(String sMsg) #c:@oe4v  
{ =H7p&DhD[  
System.err.println(sMsg); OR&pGoW  
} 4j;IyQDvM  
Sck!w 3  
'R1C-U3w,  
public static void log(int sMsg) kt Z~r. +  
{ {#+K+!SvDX  
System.err.println(sMsg); G9xl-ag+z  
} iAe"oXK|  
} "`K_5"F  
#reR<qp&]  
n$ByTmKxv  
/* =9,mt K~  
**TestMethod.java ]+G\1SN~  
*/ Jb{g{a/  
package NetFox; #_\**%,<  
 @mw1__?  
n%h009-5  
public class TestMethod { z~Zm1tZs  
|j"C52Q  
$Ud9v4  
public TestMethod() "u^2!d  
{ ///xx/weblogic60b2_win.exe 8]&Fu3M^  
try{ TS#1+f]9J<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >#dLT~[\a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3
^Is4H_8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tY#&_%W  
fileFetch.start(); u9:sj
 
} R;AcAJ;  
catch(Exception e){e.printStackTrace ();} euY+jc%  
K:XXt
G  
fBTNI`#  
} &T-:`(  
"viZ"/~6  
xe OfofC(l  
public static void main(String[] args) @/aJi6d"^E  
{ MuO(%.H  
new TestMethod(); j^/<:e c.  
} >WO;q  
} Lm$KR!z  
点击下载更多相关资料