http断点续传简单实现（java)

/* rZ|p{ym  
**SiteFileFetch.java Wy}^5]R0E  
*/ uAqiL>y  
package NetFox; ')0@J`  
import java.io.*; AO>b\,0Me  
import java.net.*; U[02$gd0l  
TA0(U$ 4  
A]TEs)#*7)  
public class SiteFileFetch extends Thread { y*ZA{  
:"MHmm=uU8  
fgeh;cD  
SiteInfoBean siteInfoBean = null; //文件信息Bean ti (Hx  
long[] nStartPos; //开始位置 57EX#:a  
long[] nEndPos; //结束位置 Le:C8^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [^s;Ggi9  
long nFileLength; //文件长度 dW%t
ph  
boolean bFirst = true; //是否第一次取文件 fLqjBG]<  
boolean bStop = false; //停止标志 T.3{}230<  
File tmpFile; //文件下载的临时信息 tsL ; wT_  
DataOutputStream output; //输出到文件的输出流 l _%<U  
1O<6=oH  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） g4b#U\D@)/  
public SiteFileFetch(SiteInfoBean bean) throws IOException IdN3Ea]  
{
/ Ws>;0  
siteInfoBean = bean; Sc
/l.]k+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); u*): D~A  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }6!/Nb  
if(tmpFile.exists ()) C#nT@;VO5  
{ 2.I|8d[  
bFirst = false; |T@SlNi]  
read_nPos(); |=*)a2  
} M:GpyE
%  
else nj:w1E/R  
{ "3\y~<8%'  
nStartPos = new long[bean.getNSplitter()]; ||>4XDV#  
nEndPos = new long[bean.getNSplitter()]; '/NpmNY:L  
} w2UEU5%  
*U,JQ  
NS2vA>n8R  
xYCJO(&  
} Vx2/^MiXy  
Yi?bY  
@;`'s  
public void run() +/Y2\s  
{ oe]*Q  
//获得文件长度 :`zO%h  
//分割文件 P%lD9<jED  
//实例FileSplitterFetch s{R,- \_  
//启动FileSplitterFetch线程 vhbHt_!u&  
//等待子线程返回 ^;<d<V}*  
try{ QMz=e  
if(bFirst) erW2>^My  
{ V~[b`&F  
nFileLength = getFileSize(); ]sqLGmUL  
if(nFileLength == -1) 4r7F8*z  
{ rAfz?  
System.err.println("File Length is not known!"); u+r!;-0i  
} Ao8ua|:  
else if(nFileLength == -2) babL.Ua8o  
{ :\P@c(c{^C  
System.err.println("File is not access!"); 8 E\zjT!#\  
} PVp>L*|BZ;  
else <
+g77NL  
{ i7-~"g  
for(int i=0;i<nStartPos.length;i++) ^J#*sn  
{ pT->qQ3;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =~hb&  
} A~PR  
for(int i=0;i<nEndPos.length-1;i++) )
gdLb}  
{ zUL,~u  
nEndPos = nStartPos[i+1]; QF/_?Tm4  
} zP%s]>hH  
nEndPos[nEndPos.length-1] = nFileLength; gAWi&  
} sFz0:SqhE  
} 3?a`@C&x  
HTT&T9]  
dhob]8b  
//启动子线程 IZj`*M%3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; olv?$]  
for(int i=0;i<nStartPos.length;i++) iW(LD1~7  
{ }+n|0xK  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h8asj0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),
wpM2{NTP  
nStartPos,nEndPos,i); 6whPW .  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hg" i;I  
fileSplitterFetch.start(); ]"Uzn  
} XLt/$Caf  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IS&qFi}W|W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 63Zu5b"O/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H]R/=OYBUh  
nEndPos = " + nFileLength); GNMOHqg4  
// fileSplitterFetch[nPos.length-1].start(); [w'Q9\,p
 
rgzra"u)  
NplyvjQN;  
//等待子线程结束 &M}X$k I  
//int count = 0; 5OI.Ka  
//是否结束while循环 B1)Eo2i#  
boolean breakWhile = false; Fb(@i  
bPxL+ +  
%US&`BT!  
while(!bStop) ;yomaAr  
{ hz4?
ku  
write_nPos(); s6 g"uF>k  
Utility.sleep(500); [[IMf-]  
breakWhile = true; Pl/ dUt_  
c EYHB1*cT  
;zJb("n  
for(int i=0;i<nStartPos.length;i++) 71R,R,  
{ AhN3~/u%7  
if(!fileSplitterFetch.bDownOver) V'j+)!w5  
{ xKSQz  
breakWhile = false; X?'cl]1?  
break; +_7a/3kh  
} f"FFgQMkv  
} ad: qOm  
if(breakWhile) .g*N+T6O  
break; jXE:aWQht  
B>L7UQ6_[  
gU
ru=p  
//count++; "5V;~}=S  
//if(count>4) 60!%^O =  
// siteStop(); _eiqs  
} 6/8K2_UeoW  
(NvjX})eh  
T"z<D+pN  
System.err.println("文件下载结束！"); Jr
!BDg  
} tdH[e0x B  
catch(Exception e){e.printStackTrace ();} gPKf8{#%e  
} ?z9!=A%<V~  
Pz2 b  
wu.l-VmGp)  
//获得文件长度 [j0[c9.p[  
public long getFileSize() +=8wZ]  
{ T ?[28|  
int nFileLength = -1; 1 jidBzu<  
try{ BI`)P+K2  
URL url = new URL(siteInfoBean.getSSiteURL()); 2xLtJR4L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zkRAul32|  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z&n[6aV'F  
(&e!u{I  
ki'$P.v{$w  
int responseCode=httpConnection.getResponseCode(); fIoc)T  
if(responseCode>=400) 4$KDf;m@  
{ tS2&S 6u  
processErrorCode(responseCode); (kLaXayn  
return -2; //-2 represent access is error @-)?uYw:r  
} ^y/Es2A#t  
{1Ra|,;  
(+|+ELfqW  
String sHeader; 5I2,za&e  
src9EeiV  
oFU:]+.+D  
for(int i=1;;i++) WVa%<  
{ Zt!#KSF7%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); YbP @  
//Utility.log(in.readLine()); Rs<q^w]  
sHeader=httpConnection.getHeaderFieldKey(i); Qfn:5B]tI  
if(sHeader!=null) #<*.{"T  
{ s?EQ  
if(sHeader.equals("Content-Length")) -O *_+8f  
{ 6j|Ncv  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); e3 v^j$  
break; 72sqt5C]  
} 2o?j{K  
} U80=
f2  
else 2&4nf/sE  
break; 1VgGF^cYR  
} WEj{2+  
} J 4gtm"2)  
catch(IOException e){e.printStackTrace ();} xQFY/Z  
catch(Exception e){e.printStackTrace ();} {^dq7!  
S&!(h {O  
>.Gmu  
Utility.log(nFileLength); uBRlvNJ  
_c>ww<*3  
B r#{  
return nFileLength; k77IXT_7u  
} OvX&5Q5  
{nKw<F2  
'
4FH9J  
//保存下载信息（文件指针位置） z}MxMx c4h  
private void write_nPos() M1/d
7d  
{ OeqKKVuQ  
try{ inGUN??  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .}\8Y=  
output.writeInt(nStartPos.length); *K|~]r(F?  
for(int i=0;i<nStartPos.length;i++) =VD],R)  
{ >_2~uF@pb  
// output.writeLong(nPos); n&:ohOH%  
output.writeLong(fileSplitterFetch.nStartPos); qk<jvha  
output.writeLong(fileSplitterFetch.nEndPos); bSsg`  
} "&2 F  
output.close(); R0RxcBtG  
} w#b@6d  
catch(IOException e){e.printStackTrace ();} zQyI4RHG[  
catch(Exception e){e.printStackTrace ();} hBX*02p  
} M3jUnp&  
Q6HJ+H-Ub  
^K<3_D>1>  
//读取保存的下载信息（文件指针位置） "/zgh  
private void read_nPos() b{<?E };%  
{ YCDH0M  
try{ SI!A?34  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !.6n=r8d  
int nCount = input.readInt(); #sw4)*v  
nStartPos = new long[nCount]; v.(dOIrX  
nEndPos = new long[nCount]; sE[`x^1'8  
for(int i=0;i<nStartPos.length;i++) n2K1X!E$  
{ d=vuy   
nStartPos = input.readLong(); G<7M;vRvP  
nEndPos = input.readLong(); 2f[;U"  
} r84^/+"T  
input.close(); ~lo43$)^  
} ~,}|~  
catch(IOException e){e.printStackTrace ();} lbAhP+B  
catch(Exception e){e.printStackTrace ();} Vc9rc}  
} %V>%AP  
J%CCUl2  
g!XC5*}  
private void processErrorCode(int nErrorCode)
)$!b`u  
{ 5_;-Qw  
System.err.println("Error Code : " + nErrorCode); $Lp [i <O]  
} WutPy_L<  
u!K1K3T6k  
FoetP`   
//停止文件下载 xF[%R{Mn'  
public void siteStop() 8s)b[Z5  
{ ]CzK{-
W  
bStop = true; :K6JrS  
for(int i=0;i<nStartPos.length;i++) *a Z1 4  
fileSplitterFetch.splitterStop(); 76!LMNf  
:i<
*~0r<  
#s{^fUN6  
} '{ _ X1  
} 3&y-xZu]  
//负责部分文件的抓取 AXlV
H%'  
**FileSplitterFetch.java S~3|1Hw*tN  
*/ Rge>20uTl$  
package NetFox; Rf!v{\  
UH MJ(.Wa-  
|,$&jSe  
import java.io.*; N6._Jb  
import java.net.*; N0p6xg~  
)
kWxp  
)95k3xo  
public class FileSplitterFetch extends Thread { q\@Zf}  
yUnV%@.  
7W)W9=&BT  
String sURL; //File URL :(A&8<}-6  
long nStartPos; //File Snippet Start Position q}Q G<%VR  
long nEndPos; //File Snippet End Position pT|
s#-}  
int nThreadID; //Thread's ID G=zNZ  
boolean bDownOver = false; //Downing is over vc
lc%ws  
boolean bStop = false; //Stop identical (p5q MP]L  
FileAccessI fileAccessI = null; //File Access interface b&P)J|Fe  
bny5e:= d  
*\XOQWrF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >Hnm.?-AWl  
{ V[(fE=cIN~  
this.sURL = sURL; 'W(u.  
this.nStartPos = nStart; c]{}|2u  
this.nEndPos = nEnd; un 5r9  
nThreadID = id; A`uHZCwJ5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 r &.~ {  
} t1w]L  
+;~N; BT  
-zFJ)!/?  
public void run() 8NfXYR#  
{ ?z.?(xZ 6  
while(nStartPos < nEndPos && !bStop) ;O}%SCF7  
{ v^JzbO~|gj  
|#_p0yPy  
?"Ez  
try{ ;<M}ZL@m  
URL url = new URL(sURL); :GIBB=D9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gkd4)\9  
httpConnection.setRequestProperty("User-Agent","NetFox");
gk|>E[.  
String sProperty = "bytes="+nStartPos+"-"; m8L *LB  
httpConnection.setRequestProperty("RANGE",sProperty); KM;H '~PZi  
Utility.log(sProperty); A^,E~Z!x  
jc"sPrv5  
~LuGfPO^  
InputStream input = httpConnection.getInputStream(); 6=/sEzS'  
//logResponseHead(httpConnection); f- XUto  
&<;T$Y  
 g!}]FQBb  
byte[] b = new byte[1024]; r,JQR)l0@V  
int nRead; ?SNacN@r  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8H4NNj Oy  
{ +ALrHFG  
nStartPos += fileAccessI.write(b,0,nRead); @/:4beh  
//if(nThreadID == 1) ~s+vJvWz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )7& -DI1  
} v^ ^Ibv  
bW=q G  
b,^ "-r  
Utility.log("Thread " + nThreadID + " is over!"); TO.b- ;  
bDownOver = true; R$awo/'^  
//nPos = fileAccessI.write (b,0,nRead); i3eF_  
} n}UJ-\$  
catch(Exception e){e.printStackTrace ();} q=W.82.U  
} >+J}mo=*  
} 5.\p]>|G1  
mS'Ad<  
j{Px}f(=  
//打印回应的头信息 Z4i))%or  
public void logResponseHead(HttpURLConnection con) x:Q\pZ  
{ !\7M7  
for(int i=1;;i++) ~6;I"0b5  
{ F- -g?Q^  
String header=con.getHeaderFieldKey(i); D>y5&`  
if(header!=null) @/^<9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Zye04&x9k  
Utility.log(header+" : "+con.getHeaderField(header)); "Ol:ni1  
else zwV!6xG  
break; \ UrD%;sq  
} DP),~8  
} X:UlL"G  
]owgsR  
|yk/iO(  
public void splitterStop() ^W$R{`  
{ x6,ozun  
bStop = true; >1`4]%  
} |~5cNm  
_O}m0c   
2"G9?)d9  
} { YQS fk  
p?L%'  
(e'8>Pv  
/* RTh=x.  
**FileAccess.java :2KHiT5  
*//文件访问(定位，写) =H)]HxEEM  
package NetFox; d
'96$e o~  
import java.io.*; /''=V.-N  
!Wr<T!T  
'!^7 *@z  
public class FileAccessI implements Serializable{ 2L&c91=wE  
lW?}Ts~'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q7lC}'2fu  
RandomAccessFile oSavedFile; k( Sda>-  
long nPos; e#/&A5#Ya  
QwX81*nx  
*1EmK.-'u  
public FileAccessI() throws IOException _$R=F/88  
{ >h8m)Q  
this("",0); ,^G+<T6  
} ZRf9'UwS  
|Lg2;P7\  
&lLk[/b  
public FileAccessI(String sName,long nPos) throws IOException ,;t:x|{%  
{ ^mq(j_E.  
oSavedFile = new RandomAccessFile(sName,"rw"); F2 B(PGa7  
this.nPos = nPos; gfK_g)'2U  
oSavedFile.seek(nPos); +\Vw:
~e  
} ~+1mH  

KfjWZ4{v  
_+48(QF<  
public synchronized int write(byte[] b,int nStart,int nLen) ht%qjE  
{ w=XIpWl  
int n = -1; !M8_PC*a  
try{ 4tm%F\Izy  
oSavedFile.write(b,nStart,nLen); tn$TyCzckW  
n = nLen; z6U'"T"a  
} 4tkT\.  
catch(IOException e) <5G(Y#s/?  
{ )f$4:Pq  
e.printStackTrace (); L6CI9C;-b  
} bIGcszWr  
Kyr
Z&E.`  
A@>/PB6n  
return n; :lXY% [!6P  
} ,+df=>$W  
t|'%0 W  
hk=[v7  
} [ifw}(  
0JtM|Mg  
DU6j0lz  
/* LN+x!#:e  
**SiteInfoBean.java vQCb?+X&  
*/ I8!>7`L  
package NetFox; u)Kiw
a  
/lR*ab  
8a*&,W  
public class SiteInfoBean { 1av#u:jy~>  
*jhgCm  
'nPI zK<v  
private String sSiteURL; //Site's URL =-Hhm($n  
private String sFilePath; //Saved File's Path .I~:j`K6  
private String sFileName; //Saved File's Name ?<jWEz=  
private int nSplitter; //Count of Splited Downloading File s3sRMB2  
\2;!}  
N4;g
"k b  
public SiteInfoBean() ,j XK  
{//nSplitter的缺省值为5 O>~@>/#  
//default value of nSplitter is 5 Q>4NUq  
this("","","",5); JYWoQ[ZO#>  
} Q  
W#U|;@"  
9]+zZP_#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w#)u+^-  
{ T(u;<}e@[  
sSiteURL= sURL; +JYb)rn$^  
sFilePath = sPath; t
RI<K  
sFileName = sName; 3ux7^au  
this.nSplitter = nSpiltter; ^Lb\k|U,\  
2'=)ese  
eV!(a8  
} cEa8l~GC<  
Fy\q>(v.  
n@tt.n!{l  
public String getSSiteURL() vWmp?m  
{ tW~kn9glZ  
return sSiteURL; +pgHCzwJE  
} #C }+  
I
)yaR+l  
}O+xs3Uv  
public void setSSiteURL(String value) 'AK '(cZ  
{ ftMlm_u  
sSiteURL = value; Ws5N|g  
} aHC%:)ww:  
~zfF*A  
%
J-:%i
 
public String getSFilePath() ;76+J)  
{ 64mh.j  
return sFilePath; 7*{l\^ism;  
} R"XycXn_$  
KWDH 35  
tJu:N'=Dy  
public void setSFilePath(String value) c

h%zu%;f  
{ G9-ETj}  
sFilePath = value; S-mpob)  
} o]tfvGvU*  
,{G\-(\  
vTFG*\Cq  
public String getSFileName() ##''d||u  
{ ZRYlm$C  
return sFileName; YGPb8!  
} :vIJ>
6lIR  
<w}^Z}fpk&  
.!<yTh  
public void setSFileName(String value) p4IyKry,  
{ !pU^?Hy=  
sFileName = value; -q9m@!L  
} h0m5oV  
6 8n ;#-X  
7]Qxt%7/>  
public int getNSplitter() [)}P{y [&  
{ G*EF_N.G0  
return nSplitter; M/Z$?nd_H  
} TU)Pi.Aa  
kF'9@*?J  
qbSI98rw  
public void setNSplitter(int nCount) g$C]ln>"9m  
{ +dLUq2  
nSplitter = nCount; p=UW ^95  
} N`7OJ)l  
} e;~(7/1  
,&3+w~Ua  
Y(`Bc8h  
/* Zs t)S(  
**Utility.java l'[;q '  
*/ cQLPgE0  
package NetFox; ~pp< T  
H0tu3Pqk  
a ub$4n!C9  
public class Utility { 1P*GIt2L  
4y}z+4  
=Bc{0p*  
public Utility() LiFR7\z  
{ ea @ H  
7;@YR
 
tk-)N+M.  
} GIYdI#0RC  
!wE% <Fh  
//线程睡眠 <t!0{FJ  
public static void sleep(int nSecond) %"c;kvw  
{ Mu:zWLM*M  
try{ ?r(vX
q\  
Thread.sleep(nSecond); &S
*{a  
} Zjn1,\(t~u  
catch(Exception e) rtJ@D2Hj^  
{ ]U~{?K'g@j  
e.printStackTrace (); < ~CY?  
} 4J`-&05O  
} K)x6F15r  
nm\f$K>Pg  
//日志
% 
+  
public static void log(String sMsg) ueU"v'h\  
{ f%_$RdU  
System.err.println(sMsg); Z%ZOAu&p  
} c]VK%zl  
Na]Z%#~  
! 1?u0  
public static void log(int sMsg) @G#`uoD  
{ RB*z."  
System.err.println(sMsg); R~A))
4<%%  
} ?$;&DoE  
} 8hy1yt6t4~  
SkipP
EhA  
COWlsca  
/* xzz@Wc^_  
**TestMethod.java M@q)\UQ'  
*/ $A74V[1^  
package NetFox; ,1|=_M31  
i)cG  
n&]J-^Tx  
public class TestMethod { Z>w@3$\z  
B (h`~pb  
hC{2LLu;n  
public TestMethod() q4@+Pi)  
{ ///xx/weblogic60b2_win.exe f]2gjQHM  
try{ -$%~EY}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9\Rk(dd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S]T71W<i  
SiteFileFetch fileFetch = new SiteFileFetch(bean); p}GTOJT}  
fileFetch.start(); ;>>:7rdYt  
} H.n|zGQTB  
catch(Exception e){e.printStackTrace ();} GRL42xp'*D  
{ ~{D(k  
Yx. t+a-  
} #0*I|gfV  
n|=yw6aV'  
b!SIs*  
public static void main(String[] args) "/^kFsvp  
{ 2&s(:=  
new TestMethod(); T|oDJ]\J  
} /YwwG;1  
} 26zif
  
点击下载更多相关资料