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http断点续传简单实现(java)

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/* !rTmR@e$/  
**SiteFileFetch.java tSv0" L  
*/ +=c am/A  
package NetFox; We`'>'W0  
import java.io.*; ^[-> )  
import java.net.*; Y?Vz(udD  
\gccQig1CJ  
}fIqH4bp  
public class SiteFileFetch extends Thread { b>cafu  
/N^~U&7  
'pP-rdx  
SiteInfoBean siteInfoBean = null; //文件信息Bean w@]jpH;WX  
long[] nStartPos; //开始位置 mVm4fHEYwU  
long[] nEndPos; //结束位置 'I/h(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 hSqMaX%G  
long nFileLength; //文件长度 2HOe__Ns  
boolean bFirst = true; //是否第一次取文件 's@MQ! *  
boolean bStop = false; //停止标志 9 Aivf+  
File tmpFile; //文件下载的临时信息 o;J;*~g  
DataOutputStream output; //输出到文件的输出流 [{F%LRCo-  
%!.M~5mCd  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) t 6u-G+}  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~v: #zU  
{ {^&@g kYY  
siteInfoBean = bean;  pbB2wt  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \~"#ld(x7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); : d'65KMi  
if(tmpFile.exists ()) [}""@?  
{ dc^Vc{26Z  
bFirst = false; }. %s xw  
read_nPos(); 9NIy#  
} & 5 <**  
else rFXSO=P?Z  
{ 2mJ:c  
nStartPos = new long[bean.getNSplitter()]; c%<2z  
nEndPos = new long[bean.getNSplitter()]; IUhp;iH  
} Ao`_",E  
b>q6:=((  
]XrE  
(5Ky6b9v  
} 3sC: jIp  
~%aJFs  
q]v,  
public void run() ,OBQv.D3>a  
{ t* z'c  
//获得文件长度 5upShtC  
//分割文件 w yD%x(  
//实例FileSplitterFetch I #l;~a<9z  
//启动FileSplitterFetch线程 >_#)3K1y8  
//等待子线程返回 GAJ~$AiwHH  
try{ P06 . 1  
if(bFirst) (Nt[v;BnO  
{ mq`5w)S)\o  
nFileLength = getFileSize(); T0L+z/N_m.  
if(nFileLength == -1) ku3D?D:V  
{ 8xo;E=`   
System.err.println("File Length is not known!"); $,`VUe{  
} YeIe\3x!N  
else if(nFileLength == -2) ]N\6h(**wy  
{ Qg>L,ZO  
System.err.println("File is not access!"); cHn;}l!I  
} Rrz'(KSDw  
else U+!UL5k  
{ wG:$6  
for(int i=0;i<nStartPos.length;i++) UT-ewXh  
{ F^TAd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D%GGu"@GO  
} -R@JIe_28f  
for(int i=0;i<nEndPos.length-1;i++) ,^+#M{Z  
{ 2E$i_jc  
nEndPos = nStartPos[i+1]; 1E^{B8cm  
} m3%ef  
nEndPos[nEndPos.length-1] = nFileLength; x[}06k'  
} E8;TLk4\  
} El1:?4;  
zPE#[\O21B  
77_g}N  
//启动子线程 ;siJ~|6)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +QupM  
for(int i=0;i<nStartPos.length;i++) z6}Pj>1  
{ Uf[T_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F(G<* lA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $:]tcY-L9  
nStartPos,nEndPos,i); $nc, ?)i!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oYg/*k7EDX  
fileSplitterFetch.start(); D3]@i&^B  
} )T<D6l Lt  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .r6YrB@['  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vu>YH)N_h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (JvQ-H  
nEndPos = " + nFileLength); ox JGJ  
// fileSplitterFetch[nPos.length-1].start(); |%3O) B  
hqWPf  
z-)*Q  
//等待子线程结束 P[1m0!,B  
//int count = 0; }RDb1~6C  
//是否结束while循环 Z3I L8  
boolean breakWhile = false; xK=J.>h3  
IKtiR8  
~e+0c'n\  
while(!bStop) rkP4<E-M  
{ q'fPNQg  
write_nPos(); (-#rFO5~l  
Utility.sleep(500); dd19z%  
breakWhile = true; Cl-S=q@>V  
G$S1#F -  
WkcH5[  
for(int i=0;i<nStartPos.length;i++) zdT->%  
{ 6BR \iZ  
if(!fileSplitterFetch.bDownOver) u[: P  
{ t0I>5#*WU  
breakWhile = false; lxCX-a`@p  
break; K#iK6)tS  
} #EEG>M*xB  
} VEr 6uvB  
if(breakWhile) kkHTbn=!  
break; d{iL?>'?^  
+H?<}N*T  
QQSH +  
//count++; Qlf 9]ug)  
//if(count>4) SAQs {M  
// siteStop(); Kyyih|{  
} 3[,wMy"  
lJ("6aT?  
rS=tcB O  
System.err.println("文件下载结束!"); c-ttds  
} sio)_8tp  
catch(Exception e){e.printStackTrace ();} } =xI3;7  
} /bu'6/!`  
KuU3DTS85Z  
K:Mujx:  
//获得文件长度 ,uKs>T^  
public long getFileSize() v hR twi  
{ o- cj&Cv%  
int nFileLength = -1; X9DM ^tt  
try{ ?'TA!MR  
URL url = new URL(siteInfoBean.getSSiteURL()); 3^j~~ "2,w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y @]8Ep  
httpConnection.setRequestProperty("User-Agent","NetFox"); DBLA% {05  
|K'Gw}fX/  
,^n-L&  
int responseCode=httpConnection.getResponseCode(); 3j]UEA^  
if(responseCode>=400) d.L OyO  
{ Dl>*L  
processErrorCode(responseCode); :h^O{"au^  
return -2; //-2 represent access is error 3$MYS^D  
} YG-Z.{d5Z  
T$#FAEz  
=I+l=;05Rd  
String sHeader; d3\OHkM0^  
9k(*?!\;  
]u\  `  
for(int i=1;;i++) DxE^#=7iH;  
{ 7=$+k]U8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); l6',  
//Utility.log(in.readLine()); Y] D7i?3N  
sHeader=httpConnection.getHeaderFieldKey(i); 3D]2$a_d  
if(sHeader!=null) Mp]yKl  
{ M@',3  
if(sHeader.equals("Content-Length")) .vCY%0oE  
{ ._8xY$l$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RPz!UMQSD  
break; ;"d?_{>7  
} 7Qm;g-)f  
} =)mXCA^  
else # Nu%]  
break; ?ZSXoy-kr  
} </K%i;l  
} j;1~=j])  
catch(IOException e){e.printStackTrace ();} a7XXhsZ  
catch(Exception e){e.printStackTrace ();} Xtu:  
/%N31   
ws*~$x?7  
Utility.log(nFileLength); Z/XM `Cy  
(#f m (@T  
ccHLL6F{  
return nFileLength; H1aV}KD  
} ?Zc/upd:$N  
fW_}!`:  
d~togTs1  
//保存下载信息(文件指针位置) pDLu+ }@  
private void write_nPos() c n\k`8  
{ gaLEhf^  
try{ cq'}2pob  
output = new DataOutputStream(new FileOutputStream(tmpFile)); XgwMppacw  
output.writeInt(nStartPos.length); 6Tm Rc  
for(int i=0;i<nStartPos.length;i++) \;3B?8wbIl  
{ z5|e\Z  
// output.writeLong(nPos); hLDch5J5~  
output.writeLong(fileSplitterFetch.nStartPos); n"^/UQ|#j  
output.writeLong(fileSplitterFetch.nEndPos); CT$& zEIm  
} wGov|[X  
output.close(); 1YF+(fk  
} ?.rH;:9To  
catch(IOException e){e.printStackTrace ();} hQd@bN8  
catch(Exception e){e.printStackTrace ();} }}4 sh5z  
} 3{2^G@j  
@%I_&!d  
h"RP>fZt  
//读取保存的下载信息(文件指针位置) 0?J|C6XM#4  
private void read_nPos() E<X{72fb>  
{ RTgQ#<W8  
try{ IGh !d?D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); d- Z+fz  
int nCount = input.readInt(); 7- *( a  
nStartPos = new long[nCount]; }[=xe(4]D  
nEndPos = new long[nCount]; I =tyQ`  
for(int i=0;i<nStartPos.length;i++) 'S%} ?#J  
{ . Ce&9l  
nStartPos = input.readLong(); }skRlC  
nEndPos = input.readLong(); 0Y38 T)k  
} B9m>H=8a  
input.close(); .-O@UQx.I  
} 8%vh6$s6/  
catch(IOException e){e.printStackTrace ();} ]Omb :  
catch(Exception e){e.printStackTrace ();} okK/i  
} avHD'zU}N  
2yEO=SN,(  
7\\~xSXh  
private void processErrorCode(int nErrorCode) L5V'Sr  
{ h a,=LV  
System.err.println("Error Code : " + nErrorCode); A4 A6F<  
} 5v Uz  
|1<]o;:  
n!l./>N  
//停止文件下载 \GbHS*\+  
public void siteStop() q{9X.-]}  
{ lgv-)5|O+H  
bStop = true; ]]h:#A2  
for(int i=0;i<nStartPos.length;i++) Y^94iOk%T  
fileSplitterFetch.splitterStop(); @^y?Bh9jQ  
=,>TpE  
'Ec:l(2Ec  
} @~!-a s7  
} 6`s%%v  
//负责部分文件的抓取 -A-hxK*^  
**FileSplitterFetch.java </+%R"`  
*/ !%Hl#Pv}  
package NetFox; {LB }v;?l  
9J2q`/6~e  
9A* ?E  
import java.io.*; <.AC=4@V  
import java.net.*; YjX!q]56  
/]MB6E7&  
V. bH$@ej  
public class FileSplitterFetch extends Thread { n }9Msen  
gvTOC F  
!CVBG *E^l  
String sURL; //File URL D_ Bx>G9  
long nStartPos; //File Snippet Start Position O%fp;Y{`  
long nEndPos; //File Snippet End Position }Pm(oR'KTJ  
int nThreadID; //Thread's ID $_URXI  
boolean bDownOver = false; //Downing is over :9!0 Rm  
boolean bStop = false; //Stop identical ulPrb>i  
FileAccessI fileAccessI = null; //File Access interface LrM.wr zI/  
evg 7d  
4U! .UNi  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "z#?OV5  
{ 8[`^(O#\E  
this.sURL = sURL; +/~\b/  
this.nStartPos = nStart; ].<sAmL^  
this.nEndPos = nEnd; z[|PsC3i:  
nThreadID = id; |0%4G k);  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $cJN9|$6  
} avxn}*:X.  
$)TF,-#x  
k+q6U[ce  
public void run() OnPy8mC  
{ C)KtM YA,  
while(nStartPos < nEndPos && !bStop) e??{&[  
{ e`Zg7CaDd  
f5=t*9_-[  
4MtqQq4%  
try{ c~L6fvS  
URL url = new URL(sURL); B0oY]r6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s68_o[[E  
httpConnection.setRequestProperty("User-Agent","NetFox"); i9EMi_%  
String sProperty = "bytes="+nStartPos+"-"; LA=>g/+i.X  
httpConnection.setRequestProperty("RANGE",sProperty); |IcxegE  
Utility.log(sProperty); Y?vm%t`K  
Fzld0p9=  
dE}b8|</  
InputStream input = httpConnection.getInputStream(); Y="&|c=w#L  
//logResponseHead(httpConnection); EYx2IJ  
q5\LdI2  
:oj) eS[Y  
byte[] b = new byte[1024]; "<.  
int nRead; ?k:])^G5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Er/5 ,  
{ 'd.@4 9  
nStartPos += fileAccessI.write(b,0,nRead); t0V_ c'm  
//if(nThreadID == 1) }DUDA%U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); " ;R3260  
} 3@cJ=   
M%5$-;6~_  
g7U:A0Z  
Utility.log("Thread " + nThreadID + " is over!"); o4[2`mT  
bDownOver = true; 18/@:u{  
//nPos = fileAccessI.write (b,0,nRead); M(h H#_ $  
} \2<yZCn  
catch(Exception e){e.printStackTrace ();} mN'9|`>V>  
} n8OdRv  
} w)m0Z4*  
k>0cTBY&  
<<2b2?a S`  
//打印回应的头信息 P7x?!71?L  
public void logResponseHead(HttpURLConnection con) V\M!]Nnxr  
{ 'y M:W cN  
for(int i=1;;i++) ^Lfn3.M  
{ U_{JM`JY  
String header=con.getHeaderFieldKey(i); CU>K  
if(header!=null) k+R?JWC:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /L|}Y242  
Utility.log(header+" : "+con.getHeaderField(header)); <9@]|  
else 4tTZkJc  
break; q'V{vFfY%  
} ot+~|Dl  
} [ rQ(ae  
wIR[2&b  
"xc*A&Sg  
public void splitterStop() gAUQQ  
{ 1707  
bStop = true; Z8dN0AqZ  
} ]>4Qs  
(Nlm4*{h  
'lRHdD}s  
} _TN$c  
&|{,4V0%A  
yzNX2u1  
/* ]ifHA# z`~  
**FileAccess.java D_ZBx+/_?  
*//文件访问(定位,写) A-wxf91+:  
package NetFox; OI}HvgV^!  
import java.io.*; MW[ 4^  
yoY)6cn@  
"A1yqK  
public class FileAccessI implements Serializable{ U}wq~fD  
-Lf6]5$2'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =]xk-MY"|R  
RandomAccessFile oSavedFile; VUv.Tx]Z[  
long nPos; >(6\ C  
rnhf(K.{3  
75}u D  
public FileAccessI() throws IOException YxkEAb!+  
{ KP7RrgOan&  
this("",0); ?ZV0   
} i|,A1c"*  
_>m*`:Wb  
|M/ \'pOe  
public FileAccessI(String sName,long nPos) throws IOException PZhZK VZx  
{ OK J%M]<  
oSavedFile = new RandomAccessFile(sName,"rw"); XXwhs-:o  
this.nPos = nPos; q vVZA*  
oSavedFile.seek(nPos); z+D,:!yF  
} 5'-9?-S"  
I2lZ>3X{  
P~ZV:Of  
public synchronized int write(byte[] b,int nStart,int nLen) ~kJpBt7M  
{ wXZY5-h4  
int n = -1; KC-aLq/  
try{ kGqf@ I+  
oSavedFile.write(b,nStart,nLen); ,L:)ZZgN  
n = nLen; h_G7T1;L  
} (dip Ks?K  
catch(IOException e) # +]! u%n  
{ V1>94/waa  
e.printStackTrace (); *Z2Q]?:{ i  
} nkj'AH"2  
842+KLS  
2b,TkG8K  
return n; @Be:+01z  
} aw"%B-N \  
/aa;M*Qp  
q.QYn.CBZz  
} Iw |[*Nu-  
>T^v4A  
r8?Lr-;  
/* : 8<^rP  
**SiteInfoBean.java X/7_mU>aKT  
*/ wP1VQUL  
package NetFox; CgKSK0/a  
?N*@o.  
p2vUt  
public class SiteInfoBean { sx^? Iw,N'  
9S1V! Jp  
64>[pZF8  
private String sSiteURL; //Site's URL w&cyGd D5  
private String sFilePath; //Saved File's Path uBkn y;  
private String sFileName; //Saved File's Name xa0%;nFKe  
private int nSplitter; //Count of Splited Downloading File TXl9c 6  
c]R![sa  
3&Rqz9W  
public SiteInfoBean() B[|/wHMsT}  
{//nSplitter的缺省值为5 $K fk=@  
//default value of nSplitter is 5 76r s)J[*w  
this("","","",5); F_ Cz  
} _-\{kJ  
&LQab>{*K  
TC#B^m`'p  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2U+p@}cQUA  
{ Ol[IC  
sSiteURL= sURL; D?F5o^e"h<  
sFilePath = sPath; m8^2k2  
sFileName = sName; H=RV M  
this.nSplitter = nSpiltter; &D w~Jq|  
]~Qkg+>'&  
/iuNdh  
} GZX!iT  
~(]DNXB8I`  
,ToEK Id  
public String getSSiteURL() 8HA=O ?Cg  
{ j5^b~F%  
return sSiteURL; M':.b+xN  
} ZSt ww{Z  
B8Zd#.6]  
*bSG48W("  
public void setSSiteURL(String value) ~At.V+  
{ 'oL[rO~j  
sSiteURL = value; Li^!OHro.  
} c6)zx b  
kxwm08/|f  
<!>}t a  
public String getSFilePath() %~2m$#)  
{ ^v|!(h\ZC  
return sFilePath; Hv*O9!cC  
} 'Pu;]sC  
|YFlJ2w  
uhLm yK  
public void setSFilePath(String value) bC-x`a@  
{ }TL"v|ny6;  
sFilePath = value; Tou~U[V+  
} hI{Yg$H1  
3U$fMLx]k  
xyz86r ^u  
public String getSFileName() v72 dE  
{ 7Z3qaXPH  
return sFileName; ,SwaDWNO  
} <);u]0  
Ec 7M'~1  
)yZE>>3-  
public void setSFileName(String value) >GUTno$J  
{ >@uYleD(  
sFileName = value; ]#.#]}=  
} K$]B" s  
e90z(EF?0  
{ rn~D5R  
public int getNSplitter() 1*jm9])#  
{ iL1so+di  
return nSplitter; ,[#f}|s_  
} s%|J(0  
nHjwT5Q+Q  
gMn)<u>  
public void setNSplitter(int nCount) jQ}| ]pj+  
{ sTyGi1  
nSplitter = nCount; /^G+vhlf\  
} ~vF o 0k(  
} a$8?0` (  
b] V=wZ o  
@7'gr>_E  
/* B=|sLs`I  
**Utility.java Hefqzu  
*/ {!h[@f4  
package NetFox; 3om-,gfZ  
jqedHn x  
}3lF;k(2g  
public class Utility { 7yl'!uz)9  
92Iv'(1ba  
"O "@HVF@  
public Utility() f}eVfAf  
{ 5GkM7Zu!{j  
kGP?Jx\PkH  
6suc:rp";  
} .`XA6e(8KR  
$@;[K \  
//线程睡眠 IRa*}MJe  
public static void sleep(int nSecond) {*9i}w|2  
{ K? k`U,  
try{ ?VsZo6Z"  
Thread.sleep(nSecond); +%v4Ci"%y  
} ;7>--_?=  
catch(Exception e) 5Ncd1  
{ iI0'z=J  
e.printStackTrace (); \-yi#N  
} "(qO}&b>  
} my6T@0R  
(eP)>G]  
//日志 t:7jlD!d  
public static void log(String sMsg) WgB,,L,  
{ owhht98y(  
System.err.println(sMsg); Rim}DfO/  
} !ZW0yCwLQ  
Y~!@  
>2/zL.O  
public static void log(int sMsg) mgWtjV 8  
{ jXf-+ ;ZQ  
System.err.println(sMsg); W+X zU"l  
} 5hMiCod  
} )j'b7)W\  
&IYkeGQr  
}I]q$3 .  
/* {5h_$a!TaU  
**TestMethod.java (%Rs&/vU~  
*/ ~fe0Ba4  
package NetFox; 3Y8 V?* 1|  
Z# 04 ]  
Tw5BvB1  
public class TestMethod { }s[/b"%y  
]\U'_G2]  
\Wk$>?+#@  
public TestMethod() aXagiz\;  
{ ///xx/weblogic60b2_win.exe Wwz{98,K  
try{ (x@"Dp=MZW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =[&Jxy>Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); </QSMs  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .9ne'Ta  
fileFetch.start(); *#_jTwQe  
} S0`*  
catch(Exception e){e.printStackTrace ();} MNzq}(p  
",m5}mk:4  
14R))Dz"  
} r[~$  
.B*)A.   
sBwgl9  
public static void main(String[] args) Ih0GzyU*4  
{  ^8iy(  
new TestMethod(); ITV}f#  
} hGeRM4zVZZ  
} vY6|V$  
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