http断点续传简单实现（java)

/* vWAL^?HUP  
**SiteFileFetch.java p/+a=Yo  
*/  w@,zFV  
package NetFox; j?'GZ d"B  
import java.io.*; `OSN\"\ad  
import java.net.*; "AE5 V'  
|i++0BU  
x.-+[l[1 !  
public class SiteFileFetch extends Thread { m*JaXa  
2}8v(%s p  
<)1qt
9  
SiteInfoBean siteInfoBean = null; //文件信息Bean !qG7V:6  
long[] nStartPos; //开始位置 &jmRA';sK  
long[] nEndPos; //结束位置 Bz,?{o6s)Q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p,#o<W  
long nFileLength; //文件长度 B_.%i+ZZ  
boolean bFirst = true; //是否第一次取文件 #\=FO>  
boolean bStop = false; //停止标志 F w?[lS  
File tmpFile; //文件下载的临时信息 =E.wv  
DataOutputStream output; //输出到文件的输出流 \-g)T}g,I  
9H]{g*kL  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） q<M2,YrbAI  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7Op>i,HZk\  
{ lnjXDoVb<  
siteInfoBean = bean; PUUwv_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6Yln,rC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !z>6Uf!{  
if(tmpFile.exists ()) m;,N)<~  
{ #{;k{~;PF  
bFirst = false; {tWf  
read_nPos(); -q

Ga]a  
} > ;*b|Ik  
else J\b^)  
{ [TmIVQ!B  
nStartPos = new long[bean.getNSplitter()]; z:wutqru  
nEndPos = new long[bean.getNSplitter()]; F1yqxWHeo  
} 6
^`1\ #f  
cz8T  
<J`0  
JJN.ugT}1  
} ;>Ib^ov  
HMNLa*CL'  
)AvN\sC  
public void run() Y^wW2-,m  
{ ~UP[A'9jJ  
//获得文件长度 MDnua  
//分割文件 "~|6tQLc  
//实例FileSplitterFetch GBPo8L"9  
//启动FileSplitterFetch线程 !2f[}.6+  
//等待子线程返回 ^'PWI{ O  
try{ I=`U7Bis"  
if(bFirst) 3`DQo%<  
{ k5'Vy8q  
nFileLength = getFileSize(); \"P%`C  
if(nFileLength == -1) b gK}-EU  
{ ig/xv  
System.err.println("File Length is not known!"); n-tgX?1'  
} AP 2_MV4W  
else if(nFileLength == -2) *nkoPVpC  
{ -lY6|79bF  
System.err.println("File is not access!"); |v3T!  
} n{argI8wF  
else 
%]}  
{ Rl?_^dPx  
for(int i=0;i<nStartPos.length;i++) _@ qjV~%Sy  
{ j8^Iz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); G[uK-U  
} Ga^"1TZ x  
for(int i=0;i<nEndPos.length-1;i++) "R;U/+  
{ ;n*.W|Uph  
nEndPos = nStartPos[i+1]; 2*laAB
 
} 2} /aFR  
nEndPos[nEndPos.length-1] = nFileLength; }C"%p8=HM  
} \ C+~m  
} .ypL=~Rp  
?N*>*"  
6]WAUK%h  
//启动子线程 vc;$-v$&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R'as0 u\  
for(int i=0;i<nStartPos.length;i++) rr],DGg+B]  
{ `EA\u]PwQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wDal5GJp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), P~>OS5^  
nStartPos,nEndPos,i); k<CJ{u0<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P64PPbP  
fileSplitterFetch.start(); :+^lJ&{U  
} Qb-M6ihcc  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /K@XzwM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @<hb6bo,N
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aFX=C>M  
nEndPos = " + nFileLength); ohGJ1  
// fileSplitterFetch[nPos.length-1].start(); pZ.ecZe/  
dd%6t  
-">;-3,K  
//等待子线程结束 JzQ_{J`k  
//int count = 0; t6"%3#s  
//是否结束while循环 vtg!8u4  
boolean breakWhile = false; |.: 
q  
tTl%oN8Qw  
G:<aB  
while(!bStop) i &nSh ]KK  
{ ,aZ[R27rpL  
write_nPos(); zZPO&akB"  
Utility.sleep(500); s%7t"-=&  
breakWhile = true; Uiw2oi&_  
{BN#h[#B{  
:%=Xm   
for(int i=0;i<nStartPos.length;i++) 
,q`\\d  
{ <`=j^LU  
if(!fileSplitterFetch.bDownOver) I3L<[-ZE  
{ 0*3R=7_},o  
breakWhile = false;  JYI,N  
break; oWT3apGO  
} xef% d G.  
} `r6,+&  
if(breakWhile) WaRw05r  
break; |mfvr*7  
X'Xx"M  
Gx/Oi)&/  
//count++; kiaw4_  
//if(count>4) +Mb.:_7'  
// siteStop(); N#_H6TfMG  
} &'`g#N  
b{&)6M)zo  
+{.WQA}z\  
System.err.println("文件下载结束！"); k1~&x$G  
} IFL*kB   
catch(Exception e){e.printStackTrace ();} C ;W"wBz9  
} S9y}  
.uZ3odMlx  
6<QQ@5_  
//获得文件长度 JX;G
<lev  
public long getFileSize() !wVM= z^G  
{ *L^,|   
int nFileLength = -1; M5X&}cN6  
try{ 83_h J  
URL url = new URL(siteInfoBean.getSSiteURL()); T.BW H2gRP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LL~%f &_  
httpConnection.setRequestProperty("User-Agent","NetFox"); !*N@ZL&X  
qR8Lh( "i  
O<?R)NH-P  
int responseCode=httpConnection.getResponseCode(); hL{KRRf>  
if(responseCode>=400) "ze|W\Bv!  
{ ea 'D td  
processErrorCode(responseCode); Bj;'qB
>3  
return -2; //-2 represent access is error ##>H&,Dp[  
} '-~~-}= sJ  
/ zPO  
zRr*7G  
String sHeader; }S-O&Z  
uy$e?{Jf  
Z@!+v19^  
for(int i=1;;i++) ?0SJfh  
{ YNF k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \_f(M|  
//Utility.log(in.readLine()); ]N?kG`[  
sHeader=httpConnection.getHeaderFieldKey(i); m;QMQeGz  
if(sHeader!=null) igPX#$0XU  
{ rjYJs*#  
if(sHeader.equals("Content-Length")) !%c\N8<>GD  
{ j A%u 5V  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
e(t\g^X  
break; 8&slu{M- t  
} &V/MmmT  
} 1mG-}  
else u^  ~W+  
break; UP,c|  
} _w+
Qy.  
} HG^'I+Yn  
catch(IOException e){e.printStackTrace ();} 1=V-V<  
catch(Exception e){e.printStackTrace ();} l]8uk^E  
MQ8J<A Pf-  
6j}9V L77  
Utility.log(nFileLength); }5"u[Z.  
( a#BV}=  
}BP;1y6-r  
return nFileLength; (9dl(QSd  
} ]c'A%:f<  
'D1xh~  
.$vK&k  
//保存下载信息（文件指针位置） Q\Vgl(;lX  
private void write_nPos() sXFZWj}\  
{ 3^yK!-Wp(  
try{ Cp0=k  
output = new DataOutputStream(new FileOutputStream(tmpFile)); utV_W&  
output.writeInt(nStartPos.length); =T7.~W  
for(int i=0;i<nStartPos.length;i++) Z,PPu&lmE/  
{ VI*$em O0  
// output.writeLong(nPos); *s3/!K  
output.writeLong(fileSplitterFetch.nStartPos); )9]PMA?u  
output.writeLong(fileSplitterFetch.nEndPos); Xsa].  
} Iu=(qU  
output.close(); CU!Dhm/U  
} tQ#n${a@f  
catch(IOException e){e.printStackTrace ();} #Gi$DMW  
catch(Exception e){e.printStackTrace ();} N8df8=.kw  
} t%8BK>AHvw  
;!Fn1|)  
p5*EA x  
//读取保存的下载信息（文件指针位置） _lq`a\7e  
private void read_nPos() 2GG2jky{/  
{ }^\oCR@  
try{ ]6j{@z?{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f _:A0  
int nCount = input.readInt(); <1TAw.  
nStartPos = new long[nCount]; -mh3DhJ,  
nEndPos = new long[nCount]; #AY&BWS$  
for(int i=0;i<nStartPos.length;i++) RxQ*  
{ \Vk:93OH21  
nStartPos = input.readLong(); ;n;p@Uu[ b  
nEndPos = input.readLong(); |DwZ{(R"W  
} 
:k#HW6p  
input.close(); #O&8A  
} gRzxLf`K  
catch(IOException e){e.printStackTrace ();} \w8\1~#  
catch(Exception e){e.printStackTrace ();} 3OB"#Ap8<  
} ;kKyksxlD  
s>c=c-SP.  
-nwypu  
private void processErrorCode(int nErrorCode) Vjpy~iP4B  
{ NHE18_v5  
System.err.println("Error Code : " + nErrorCode); c
Z3v=ke^  
} 0"SU_jQzv  
?V=CB,^  
~VB1OLgv#.  
//停止文件下载 CvdN"k  
public void siteStop() B<C&xDRZ0  
{ 8FhdN  
bStop = true; w!XD/jN  
for(int i=0;i<nStartPos.length;i++) }-2|XD%]  
fileSplitterFetch.splitterStop(); Uw:"n]G]D?  
}-`4DHgq  
u%!@(eKM-  
} nr3==21Om4  
} +cRn%ioVi  
//负责部分文件的抓取 rT>wg1:  
**FileSplitterFetch.java 3(UVg!t  
*/ '<uq3?5  
package NetFox; cH)";]k*-  
[-x7_=E#  
V~ _>U}  
import java.io.*; 4&iCht =  
import java.net.*; P2nu;I_&  
I`#JwMU;m  
4P
o_-4  
public class FileSplitterFetch extends Thread { S8gs-gL#Og  
8b=_Y;  
3$JoDL(Z  
String sURL; //File URL }PpUAt~g  
long nStartPos; //File Snippet Start Position @o.I;}*
N  
long nEndPos; //File Snippet End Position FiU#T.`9'  
int nThreadID; //Thread's ID A%-6`>  
boolean bDownOver = false; //Downing is over M3Kfd  
boolean bStop = false; //Stop identical 13wE"-  
FileAccessI fileAccessI = null; //File Access interface ,z?':TZ  
?X;RLpEc|A  
y+;|
Fz  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException I}Q2Vu<  
{ XfmwVjy  
this.sURL = sURL; DTs;{c  
this.nStartPos = nStart; 1:wQ.T  
this.nEndPos = nEnd; K|@G t%Y  
nThreadID = id; .|=\z9_7S8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9!tW.pK5  
} 92-I~ !d  
-']56o_sQ/  
.p$(ZH =~  
public void run() QCJM&  
{ C*lJrFpB  
while(nStartPos < nEndPos && !bStop) ?1".;foZ  
{ L=h'Qgk%  
\[nut;  
:H[6Lg\*  
try{ .8|X   
URL url = new URL(sURL); jqkqZF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @|)Z"m7  
httpConnection.setRequestProperty("User-Agent","NetFox"); rQ9'bCSr%  
String sProperty = "bytes="+nStartPos+"-"; ~_a-E  
httpConnection.setRequestProperty("RANGE",sProperty); `,0}ZzaV&  
Utility.log(sProperty); RT5T1K08I  
?hM64jI|  
Hr4}3.8  
InputStream input = httpConnection.getInputStream(); ,2)6s\]/b  
//logResponseHead(httpConnection); +^<](z  
cS+>J@L  
E!AE4B1bd  
byte[] b = new byte[1024]; 5M_H NWi4  
int nRead; A(0lM`X  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |)G<,FJQE_  
{ W'.m'3#z  
nStartPos += fileAccessI.write(b,0,nRead); $mB;K]m  
//if(nThreadID == 1) ]:\dPw
`A  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9k=3u;$v  
} yOKI*.}  
Q5_o/wk  
[trwBZ^D~  
Utility.log("Thread " + nThreadID + " is over!"); 6`-jPR  
bDownOver = true; snikn&  
//nPos = fileAccessI.write (b,0,nRead); 'P}0FktP`  
} ,v&(YOd  
catch(Exception e){e.printStackTrace ();} EZ`{
Wnbq  
} o8vug$=Z  
} b_):MQ1
{  
v9->nVc-  
 rXU\  
//打印回应的头信息 I`p;F!s  
public void logResponseHead(HttpURLConnection con) <d_!mKw  
{
!Rt>xD  
for(int i=1;;i++) 9&ids!W~yx  
{ kSh( u  
String header=con.getHeaderFieldKey(i); 1'\/,Es  
if(header!=null) b%5f&N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); tnG# IU *  
Utility.log(header+" : "+con.getHeaderField(header)); J)C/u{o  
else
eGHaY4|  
break; m9Hit8f@Q  
} XSlGE9]AG  
} >e"#'K0?\  
mdgi5v  
t`mV\)fa
 
public void splitterStop() 8ITdS
g  
{ W{gb:^;zb  
bStop = true; ?1eK#Z.  
} |H+Wed|  
J9[r
|`gJ(  
`^y7f  
} C 6AUNRpl  
xUistwq  
\} :PLCKT  
/* d;}nh2*  
**FileAccess.java tC9n k5~  
*//文件访问(定位，写) igR";OQk  
package NetFox; 1 Ya`| ?FS  
import java.io.*; Hg$lXtn]  
~`:L?Jkb6H  
6b\&~b@T  
public class FileAccessI implements Serializable{ 'ub@]ru|  
MFAH%Z$  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7s{GbU\  
RandomAccessFile oSavedFile; e;}7G  
long nPos; /CG"]!2 "  
R[x_j  
}d}Ke_Q0  
public FileAccessI() throws IOException [^98fAlz6  
{ _t #k,;  
this("",0); R',rsGd`6j  
} cq/$N  
8C9-_Ng`  
VZmLS 4E  
public FileAccessI(String sName,long nPos) throws IOException D\NKC@(M  
{ o="M  
oSavedFile = new RandomAccessFile(sName,"rw"); 76h ,]xi  
this.nPos = nPos; o!ebs0  
oSavedFile.seek(nPos); SmSH2m-  
} "]b<uV
  
o]M5b;1  
;P%1j|7  
public synchronized int write(byte[] b,int nStart,int nLen) )"aV* "  
{ y''z5['  
int n = -1; ~;{;,8!)  
try{ CD( :jM?  
oSavedFile.write(b,nStart,nLen); MC.)2B7  
n = nLen; MJ [m  
} DKJmTH]rUg  
catch(IOException e) /zVOK4BqN+  
{ 0Y{yKL  
e.printStackTrace (); !0LWa"  
} G[I"8iS,  
1+{{EOZ4  
;dZZ;#k%  
return n; }"%?et(  
} NzOx0WLF  
W^LY'ypT  
a:IC)]j$_  
} jc[Y}gd,  
Y}|X|!0x  
;1O_M9  
/* YdC6k?tzS  
**SiteInfoBean.java l=)x
o@6  
*/ ,|H `e^  
package NetFox; dkBIx$t  
Rmt~,cW!\  
*>'V1b4}  
public class SiteInfoBean { &LZn FR  
qqr?!vem6  
dx{bB%?Y\=  
private String sSiteURL; //Site's URL oiT[de\S  
private String sFilePath; //Saved File's Path udUyh%n  
private String sFileName; //Saved File's Name YPK(be_|I  
private int nSplitter; //Count of Splited Downloading File u9GQU  
m6&~HfwN  
%wvdn  
public SiteInfoBean() "ZoRZ'i  
{//nSplitter的缺省值为5 =eXU@B  
//default value of nSplitter is 5 E}Z/*lX  
this("","","",5); OXSmt DvJ  
} q#ClnG*  
D] jzAx  

FR4QUk  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #TX/aKr:  
{ tip+q d  
sSiteURL= sURL; G"U9E5O  
sFilePath = sPath; >G*eNn  
sFileName = sName; ](9Xvy  
this.nSplitter = nSpiltter; wQH<gJE/:  
st3l2Q  
5k3b3&  
} N~d?WD\^  
>:S?Mnv6  
6?mibvK  
public String getSSiteURL() zRl3KjET  
{ p7VTa~\zA  
return sSiteURL; qL&[K>2z  
} W5lR0)~#*  
o"Euwh!!  
YEs&  
public void setSSiteURL(String value) lL3khJ:%  
{ S)k*?dQ##R  
sSiteURL = value; {M$1N5Eh  
} a 3b/e8c  
/-ch`u md  
be{H$9'
 
public String getSFilePath() tl4V7!U@^z  
{ m
)zUU  
return sFilePath; #*uL)2nR  
} FLCexlv^  
2d(e:rh]  
FQ2  
public void setSFilePath(String value) YTpSHp
f@  
{ o\<ULW*  
sFilePath = value; Ic:(Gi- %  
} +L|?~p`
V  
0hNA1Fh{U  
fue(UMF~  
public String getSFileName() _476pZ_  
{ Co_A/  
return sFileName; @=Uh',F  
} D/B8tf+V  
|y# Jx  
He/8=$c%  
public void setSFileName(String value) "3"V3w  
{ '!cCMTj  
sFileName = value; Oo8VeRZ  
} [nG<[<0G;  
Lpz>>}  
/?'FE 7Y  
public int getNSplitter() 4 Y9`IgQ  
{ E *6Cw l  
return nSplitter; \fr~
  
} V-2(?auZd  
Rz:]\jcIT/  
,~$p,ALwN7  
public void setNSplitter(int nCount) sPQQ"|wU  
{ KHu+9eX  
nSplitter = nCount; m@F`!qY~Y\  
} fS:&Ak ];  
} qzLP
w*;  
D~iz+{Q4  
AW'0,b`v  
/* e8!5I,I  
**Utility.java =tn)}Y.<e  
*/ 9C9oUtS  
package NetFox; c?*=|}N  
7\[@m3s  
VG#EdIiI  
public class Utility { 3E]plj7$  
SrJGTuXg  
wqs?828x  
public Utility() rmm0/+jY  
{ b<ZIWfs  
OU.6bmWy|  
Tc:)- z[o  
} 8z`G,qh  
9uO 2Mm  
//线程睡眠 cn3\k
T*  
public static void sleep(int nSecond) +oML&g-g_  
{ F6|]4H.3Q  
try{ eA?RK.e  
Thread.sleep(nSecond); QXFo1m  
} LEf^cM=>  
catch(Exception e) 5yo%$i8I  
{ 2(+
2+}  
e.printStackTrace (); RJ&RTo  
} EGS)b  
} vWv"  
xml7Uarc  
//日志 lU\[aNs  
public static void log(String sMsg) KC6.Fr{  
{ 5d^sA;c  
System.err.println(sMsg); ! E5HN :#  
} }C?'
BRX  
i)#dWFDTv  
2- h{N  
public static void log(int sMsg) #A/  
{ TDjm2R~9FS  
System.err.println(sMsg); C2I_%nU Z1  
} eJ-xsH*8  
} "|q&ea rc  
P|E| $)m  
n;_sG>N  
/* f~R(D0@  
**TestMethod.java _6hQ %hv8  
*/ G~[x 3L'  
package NetFox; |aS.a&vwR  
lb3bm)@:  
-@2iaQ(5a2  
public class TestMethod { -d/ =5yxL  
: *#-%0  

7xlkZF  
public TestMethod() AV]2euyn  
{ ///xx/weblogic60b2_win.exe ? :%@vM  
try{ Of#u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qYQl,w  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); z&\a:fJ&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Dml;#'IF3  
fileFetch.start(); i1d'nxk6  
} {}przrU^c  
catch(Exception e){e.printStackTrace ();} u&vf+6=9Dd  
9W5lSX#^;  
nR~@#P\  
} _|2:_N=   
sll\g  
g$-PR37(  
public static void main(String[] args) 5C]x!>kX  
{ ? OM!+O  
new TestMethod(); ADzhNfS
 
} PC8Q"O  
} >tr}|>  
点击下载更多相关资料