http断点续传简单实现（java)

/* > `eo0  
**SiteFileFetch.java rU"A
O}6\@  
*/ \R@}X cqZ  
package NetFox; <ZZfN@6  
import java.io.*; P;25F
 
import java.net.*; hl**G4z9q  
GYIQ[#'d7  
DL~! ^fx  
public class SiteFileFetch extends Thread { 0K.$C~C  
"gI-S[  
@(a~p  
SiteInfoBean siteInfoBean = null; //文件信息Bean M<Z#4Gg#4  
long[] nStartPos; //开始位置 W3\+51P  
long[] nEndPos; //结束位置 A ;`[
va  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 CpN*1s})d  
long nFileLength; //文件长度 wjX0r7^@  
boolean bFirst = true; //是否第一次取文件 h6LjReNo  
boolean bStop = false; //停止标志 t"%~r3{  
File tmpFile; //文件下载的临时信息 AM!P?${a  
DataOutputStream output; //输出到文件的输出流 av(qV$2  
7eM6 B#rI  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EMH-[EBx  
public SiteFileFetch(SiteInfoBean bean) throws IOException EiM\`"o  
{ ~8k`~t!
 
siteInfoBean = bean; ]A-LgDsS  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jK6dI 7h  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %iIr %P?  
if(tmpFile.exists ()) l@UF-n~[  
{ u_ :gqvC=  
bFirst = false; 9} C(M?d  
read_nPos(); L)|hjpQ  
} {
yf,:5  
else <]S M$)=D  
{ nrpbQ(zI*  
nStartPos = new long[bean.getNSplitter()]; hZ<FCY,/?  
nEndPos = new long[bean.getNSplitter()]; %:l\Vhhz  
} C&d,|e "\  
r7U[QTM%  
8_D:#i  
^|rzqXW  
} 
ri"=)]  
x51p'bNy  
^JIs:\g<<  
public void run() }FV_jJ  
{ z9AX8k(B6  
//获得文件长度 E0r#xmk  
//分割文件 :]\-GJV5  
//实例FileSplitterFetch ezJ^ r,D|  
//启动FileSplitterFetch线程 #c<F,` gdi  
//等待子线程返回 9J49s1  
try{ u`+kH8#  
if(bFirst) /6N!$*8  
{ )J\ JAUj  
nFileLength = getFileSize(); `a7b,d  
if(nFileLength == -1) +Sv2'& B  
{ ]Ah<kq2sk  
System.err.println("File Length is not known!"); zBrqh9%8e  
} !qs~j=;y3  
else if(nFileLength == -2) G"yhu +  
{ G\f:H%[5[  
System.err.println("File is not access!"); 'OYnLz`"6  
} , YE+k`:  
else ^jo*e,y:  
{ a!x?Apww  
for(int i=0;i<nStartPos.length;i++) <m`Os2#  
{ Rwmr[g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w01\KV  
} :(jovse\  
for(int i=0;i<nEndPos.length-1;i++) NTM.Vj -_h  
{ hdH-VR4  
nEndPos = nStartPos[i+1]; d{'u97GDc  
} gWj
z3ob  
nEndPos[nEndPos.length-1] = nFileLength; |2X+( F Ed  
} \xZ6+xZd1  
} t_X=x`f  
F,GG>(6c  

QbAEWm  
//启动子线程 NzID[8`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; );z/ @Q  
for(int i=0;i<nStartPos.length;i++) 9@p+g`o  
{ *zPz)3;
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G`jJKiC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .)=j~}\  
nStartPos,nEndPos,i); V
elX+|w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^MZ9Zu_  
fileSplitterFetch.start(); YQfQ[{kp  
} ( v=Z$#l  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |Tl2r,(+R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +-:G+9L@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -
v WXL  
nEndPos = " + nFileLength); TbR
Ee;1  
// fileSplitterFetch[nPos.length-1].start(); 1,G f;mcQ  
FVHR  
DVyxe
}  
//等待子线程结束 a*@4W3;7  
//int count = 0; /{X2:g{  
//是否结束while循环 T 3+lYE  
boolean breakWhile = false; pXxpEv  
9d,2d5Y  
pB]+c%\  
while(!bStop) Je~Ybh  
{ ]M9r<x*  
write_nPos(); V)r6bb{^  
Utility.sleep(500);  %?:eURQ  
breakWhile = true; =g^JJpS  
lLeN`{?  
5l(NX  
for(int i=0;i<nStartPos.length;i++) dr7ry"5Zq  
{ :j#Fq d[DF  
if(!fileSplitterFetch.bDownOver) )VR/a  
{ W\yaovAt  
breakWhile = false; =_dqoAF  
break; 4ze4{a^  
} L{i|OK^e  
} Rlf#)4  
if(breakWhile) ZzO.s$  
break; \>XkK<ye  
6~6*(s|]A  
-jsk-,  
//count++; m3K .\3  
//if(count>4) 6/thhP3`-  
// siteStop(); 3LD`Ep   
} ]^CNC0  
)h?Pz1-W1  
?qjlWCV|e  
System.err.println("文件下载结束！"); ?wS/KEl=O  
} q]o^Y  
catch(Exception e){e.printStackTrace ();} |b:91l  
} , 8F(R%v  
ZzuWN&  
z@em1W0?Z  
//获得文件长度 d_}q.%*  
public long getFileSize() 2r&T.  
{ r$Ck:Q}  
int nFileLength = -1; <ekLL{/O'  
try{ d>NM4n[h8  
URL url = new URL(siteInfoBean.getSSiteURL()); @5\ns-%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |\~!oN  
httpConnection.setRequestProperty("User-Agent","NetFox"); U*6)/.J  
9AdA|/WV  
g>O O '}lF  
int responseCode=httpConnection.getResponseCode(); o}K!p%5_  
if(responseCode>=400) d$`NApr  
{ ueazAsk3g  
processErrorCode(responseCode); RZ&T\;m,7  
return -2; //-2 represent access is error (>\w8]  
} =m?x|Zc_v  
!,< )y}L^)  
?5g0#wqI  
String sHeader; Jk!*j  
I=I'O?w  
!*C9NX  
for(int i=1;;i++) <);Nc1  
{ $R[ggH&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); AR-&c 3o  
//Utility.log(in.readLine()); Xy(o0/7F9  
sHeader=httpConnection.getHeaderFieldKey(i); u`vOKajpH$  
if(sHeader!=null) 7 a}qnk%  
{ DVq5[ntG  
if(sHeader.equals("Content-Length")) .3.oan*i  
{ gf8DhiB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ESl</"<J  
break; $NtbI:e{  
} _*O^|QbM  
} +5+?)8Ls  
else n^AQ!wC  
break; 2& l~8,  
} hs"=>(P)  
} o4"7i 9+g  
catch(IOException e){e.printStackTrace ();} M1/Rba Q  
catch(Exception e){e.printStackTrace ();} q-fxs8+m|  
( o_lH2  
!5P\5WF~Y  
Utility.log(nFileLength); _JjR= m  
O:Fnxp5@  
_8CE|<Cn  
return nFileLength; m*MfGj(  
} / b_C9'S  
(hn@+hc  
6:(*
u{  
//保存下载信息（文件指针位置） Iu`xe  
private void write_nPos()
S=
o1k  
{ !V6O~#  
try{ q >|:mXR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); n~g,qEI;<x  
output.writeInt(nStartPos.length); <QyJJQM  
for(int i=0;i<nStartPos.length;i++) *c+Kqz-  
{ F`$V H^%V  
// output.writeLong(nPos);
$=iV)-  
output.writeLong(fileSplitterFetch.nStartPos); .}>DEpc:n  
output.writeLong(fileSplitterFetch.nEndPos); 9o]h}Xc  
} N{u4  
output.close(); lIg;>|'Z5&  
} j~eYq  
catch(IOException e){e.printStackTrace ();} 6mnj!p]3  
catch(Exception e){e.printStackTrace ();} z;_fO>u:  
} D,rF?t>=S  
w34&m  
`H5n_km  
//读取保存的下载信息（文件指针位置） dcgz<m  
private void read_nPos() >+w(%;i;  
{ ,3t('S
E  
try{ 8()L}
@y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hDp -,ag{  
int nCount = input.readInt(); JwNG`MGc  
nStartPos = new long[nCount]; K>2mm!{  
nEndPos = new long[nCount]; _Kp{
b"G  
for(int i=0;i<nStartPos.length;i++) a+TlZE>8  
{ pFLR!/J
  
nStartPos = input.readLong(); 9~^%v zM  
nEndPos = input.readLong(); n y7
G  
} $W46!U3  
input.close(); J2BW>T!tuw  
} MjAF&bD^  
catch(IOException e){e.printStackTrace ();} 0
pWF\<IZ  
catch(Exception e){e.printStackTrace ();} lH6z
Z8rh  
} @tY)s  
))" *[  
/Ot=GhN]  
private void processErrorCode(int nErrorCode) u.t(78N  
{ OKU9v{  
System.err.println("Error Code : " + nErrorCode); 8,BNs5  
} _yq"F#,*  
:h1-i  
0Dj<-n{9  
//停止文件下载 ;IC:]Zu  
public void siteStop() HB+\2jEE  
{ +)C?v&N  
bStop = true; QfuKpcT&  
for(int i=0;i<nStartPos.length;i++) d~](S<k  
fileSplitterFetch.splitterStop(); ^FJ=/#@T  
;&Q8xC2  
P#/k5]g  
} ]o<'T.x  
} :*aBiX"  
//负责部分文件的抓取 :xitV]1.   
**FileSplitterFetch.java $6~D 2K  
*/ 4#$~gTc@  
package NetFox; qm
-G=EX  
x[+t  
NGD?.^ (G  
import java.io.*; B{wx"mK  
import java.net.*; Iz/o|o]#  
8}3dwr;-  
c7mIwMhl~  
public class FileSplitterFetch extends Thread { n&Q{ [E  
*Z! #6(G  
'k=GSb  
String sURL; //File URL A2{u("^[6  
long nStartPos; //File Snippet Start Position #>+O=YO  
long nEndPos; //File Snippet End Position - Dm/7Sxd`  
int nThreadID; //Thread's ID 7q>WO  
boolean bDownOver = false; //Downing is over HhN;&67~Z  
boolean bStop = false; //Stop identical .'md `@t  
FileAccessI fileAccessI = null; //File Access interface x:W nF62  
kw8?:: <  
6b9 oSY-8  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `+[e]dH  
{ -iu7/4!j  
this.sURL = sURL; ^YddVp  
this.nStartPos = nStart; A"t~ )  
this.nEndPos = nEnd; CA7ZoMB#  
nThreadID = id; hr&&"d {s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m}\G.$h4  
} p2N;-  
D[2I_3[wp  
3fJGJW!zu  
public void run() f>k<
I[C<  
{ ]iewukB4  
while(nStartPos < nEndPos && !bStop) isaDIl;L/  
{ NIcPjo  
xS%
Z   
T^3_d93}d  
try{ XK[cbVu  
URL url = new URL(sURL); zKr\S|yE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Hi$J@xU  
httpConnection.setRequestProperty("User-Agent","NetFox"); T/DKT1P-  
String sProperty = "bytes="+nStartPos+"-"; A`Vz5WB  
httpConnection.setRequestProperty("RANGE",sProperty); 8OoKP4,;  
Utility.log(sProperty); `mTpL^f  
xSFY8  
VG*Tdaua~  
InputStream input = httpConnection.getInputStream(); Q}p+/-U\  
//logResponseHead(httpConnection); }D_h*9  
~|e?@3_G  
RG [*:ReB9  
byte[] b = new byte[1024]; \ct)/  
int nRead; @= f2\hU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~^((tT  
{ LAG*H  
nStartPos += fileAccessI.write(b,0,nRead); L&O!"[++  
//if(nThreadID == 1) Az.(tJ X"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5z8CUDt 0  
} n?vw|'(}  
'_& Xemz  
q<mDs$^K  
Utility.log("Thread " + nThreadID + " is over!"); /t=R~BJu  
bDownOver = true; Z?k4Kb  
//nPos = fileAccessI.write (b,0,nRead); H!Gsu$C  
} xc[LbaBG  
catch(Exception e){e.printStackTrace ();} pPt7M'uL"  
} %n-:mSus  
} h#Cq-^D#~  
DIR_W-z  
hGmJG,H  
//打印回应的头信息 (q'w"qj  
public void logResponseHead(HttpURLConnection con) KE3/sw0  
{ XQAdb"
`  
for(int i=1;;i++) tZlz0BY!  
{ *RugVH4  
String header=con.getHeaderFieldKey(i); M)td%<_  
if(header!=null) 4.)
hCb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !=j\pu} Z  
Utility.log(header+" : "+con.getHeaderField(header)); dI'cZt~n  
else l:v:f@M&
 
break; N*6Y5[g!\  
} bF:]MB^VK  
} |=H*" (  
cI)T@Zg_o+  
?0_Bs4O\  
public void splitterStop() mo1(dyjx  
{ M`!\$D  
bStop = true; x&qC~F*QR%  
} Jolr"F?  
E)liuu!qI  
OYKeu(=L  
} OZ\]6]L  
e573UB  
16"eyt>  
/* ]Igd<  
**FileAccess.java *sI`+4h[  
*//文件访问(定位，写) 8x$BbK  
package NetFox; \ FW{&X9a  
import java.io.*; 0{bGVLp  
ssVO+ T  
jEr
/*kv  
public class FileAccessI implements Serializable{ l]Ozy@ Ib  
=KfV;.&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 m
1DzUq;  
RandomAccessFile oSavedFile; :A%|'HxH3  
long nPos; G0p|44_~t  
&9bsTm  
k2Yh?OH  
public FileAccessI() throws IOException X2b<_j3  
{ A<ca9g3  
this("",0); D<9FSxl6  
} q]F2
bo  
T1TKwU8l  
b X.S`  
public FileAccessI(String sName,long nPos) throws IOException rZ<n0w  
{ S;DqM;Q  
oSavedFile = new RandomAccessFile(sName,"rw"); )-$Od2u2c  
this.nPos = nPos; nbM[?=WS  
oSavedFile.seek(nPos); ycAQHY~n  
} ]jNv}{  
bDI#'F  
bqEQP3t^  
public synchronized int write(byte[] b,int nStart,int nLen) ~\A(xmW}  
{ P/;sZo  
int n = -1; :
wiQ^ea  
try{ zbsdK  
oSavedFile.write(b,nStart,nLen);  y/t{*a  
n = nLen; E!.>*`)?.  
} 3vx*gfr3  
catch(IOException e) ^CZ!rOSv  
{ (jYHaTL6Y'  
e.printStackTrace (); S;#S3?G  
} ab?   
Oga/  
{fXD@lhi  
return n; 4DY\QvW5  
} ((i%h^tGa;  
+4G]!tV6  
8[  
} 7UQFAt_r  
YCvIB'  
$$7Mq*a>  
/* p!5oz2RK  
**SiteInfoBean.java JWhi*je  
*/ TR:V7d  
package NetFox; df_hmkyj  
X yi[z tN  
JvFd2@  
public class SiteInfoBean { [DS.@97n  
* SH5p  
Ua^#.K  
private String sSiteURL; //Site's URL hl`4_`3y  
private String sFilePath; //Saved File's Path h}PeXnRU  
private String sFileName; //Saved File's Name ]?!#*<t r  
private int nSplitter; //Count of Splited Downloading File R;+vE'&CO  
??&Q"6Oe  
&2-d
ZK  
public SiteInfoBean() &DoYz[q  
{//nSplitter的缺省值为5 ;&B;RUUnTO  
//default value of nSplitter is 5 3F fS2we  
this("","","",5); V8`o71p  
} eZes) &4  
0XV8B  
,PH;j_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) OwXw9  
{ &AR@5M u  
sSiteURL= sURL; ? <b>2j  
sFilePath = sPath; P|,@En 1!  
sFileName = sName; 'Fi\Qk'D@  
this.nSplitter = nSpiltter; jWHv9XtW  
C3EQzr`  
eUP.:(E  
} nrqr p  
F_>OpT  
J3Ipk-'lx  
public String getSSiteURL() 64]_o/u5W4  
{ F+yu[Dh:  
return sSiteURL; lYz{#UX}  
} m2wGg/F5  
_P6e%O8C#  
3[mVPV  
public void setSSiteURL(String value) ~qFuS933  
{ gaFOm9y.e  
sSiteURL = value; OW}ny  
} >bQ'*!  
a,<l_#'  
J1P jM
b}  
public String getSFilePath() /)6+I(H  
{ quXL'g  
return sFilePath; ZDHm@,d  
} NP }b  
$tKz|H)  
;+:C  
public void setSFilePath(String value) 8YroEX[5l  
{ dk<) \C"  
sFilePath = value; W=zHD9  
} }<m'Nkz<X  
#0OW0:Q  
-U&k%X   
public String getSFileName() p6)Jzh_/  
{ ]7
0V  
return sFileName; )4h4ql W  
} mn5y]:;`  
0\W
6X;?  
A7U]wW9  
public void setSFileName(String value) Sv&_LZ-"P  
{
=$kSvCjP  
sFileName = value; 2
G=prS`s  
} ySkz5K+|g  
GYp}V0  
"d1~(0=6<m  
public int getNSplitter() .W;,~.l  
{ bF_SD\/  
return nSplitter; jP(|pz  
}  ,2yIKPWk  
](%EQ[  
V{qpha4'P  
public void setNSplitter(int nCount) 94uAt&&b(  
{ T#M_2qJ1=  
nSplitter = nCount; Mk-zeq<2z  
} z89
!\Q  
} b!lS=zIN  
zDakl*  
6*W7I-A  
/* "pRi1Y5)l  
**Utility.java @Z}TF/Rx4  
*/ ,)u1r3@I^  
package NetFox; ^T>P  
%s&"gWi  
0j\} @  
public class Utility { }\#u~k!l  
:'6vIPN5  
ya`Z eQ-p  
public Utility() K9\r2w'T'  
{ >`E (K X  
"`6pF8k  
uV=ZGr#o  
} Z'!Ii+'6  
pB(|Y]3A  
//线程睡眠 =lb5 #  
public static void sleep(int nSecond) }Od=WQv+  
{ #(Xv\OE  
try{ 2E0A`  
Thread.sleep(nSecond); Z;'5A2  
} {TOz}=R"3h  
catch(Exception e) @~ 6,8nQ  
{ 
ro}WBv  
e.printStackTrace (); T<ka4  
} K=K]R01/o  
} 4tA`,}ywPq  
P7`RAz  
//日志 O3/w@q Q
 
public static void log(String sMsg) $cSmubZK  
{ }uFV\1  
System.err.println(sMsg); &s0_^5B0  
} Z [Q jl*  
3[*x'"Q;H  
%(}%#-X  
public static void log(int sMsg) )B$Uo,1  
{ X$A[~v  
System.err.println(sMsg); '.gLqm}%  
} mb GL)NI  
} yg WwUpY  
FlyRcj  
zkm#w  
/* -`cNRd0n  
**TestMethod.java *L{^em#b  
*/ ZCAg)/  
package NetFox; &iTTal.6  
WupONrH1e  
$?*XPzZ  
public class TestMethod { $z,rN
\[  
-n"7G%$M  
i|!D  
public TestMethod() ?{]"UnyVE*  
{ ///xx/weblogic60b2_win.exe Yc`PK =!l  
try{ $aC%&&+wG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w,zm$s^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pY$DOr-r`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2J&J  
fileFetch.start(); 9i`MUE1Sh  
} pP)> x*1  
catch(Exception e){e.printStackTrace ();} fn3D
oD+I  
/P[@o  
@W.0YU0|J  
} 2{A/Fbk  
l\6.f_  
dTVh{~/  
public static void main(String[] args) R^VmNj  
{ Ae8P'FWB>  
new TestMethod(); [A
'9sxG  
} rCsH 0:l8P  
} {fxytiH8  
点击下载更多相关资料