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http断点续传简单实现(java)

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/* Pe,;MP\2  
**SiteFileFetch.java 9H$g?';  
*/ !V( `ZH  
package NetFox; oYq,u@oM  
import java.io.*; sQ(1/"gb  
import java.net.*; lS{4dvr?w  
lV7IHX1P  
4 ?2g&B\  
public class SiteFileFetch extends Thread { n2 na9dX)w  
[a D:A  
xT+ ;w[s  
SiteInfoBean siteInfoBean = null; //文件信息Bean Z}f^qc+  
long[] nStartPos; //开始位置 XIN5a~[z*  
long[] nEndPos; //结束位置 tMG@K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2E$i_jc  
long nFileLength; //文件长度 ^fZGX<fH   
boolean bFirst = true; //是否第一次取文件 LY1KQuY  
boolean bStop = false; //停止标志 r03I*b  
File tmpFile; //文件下载的临时信息 z[FI2jl  
DataOutputStream output; //输出到文件的输出流 8 DL hk  
ris;Iu^v0  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Uf[T_  
public SiteFileFetch(SiteInfoBean bean) throws IOException [#zE. TW  
{ $nc, ?)i!  
siteInfoBean = bean; Uk"Y/Ddm  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {*nEKPq(_*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :>ZzP:QD  
if(tmpFile.exists ()) 67ZYtA|t  
{ wjg}[R@!  
bFirst = false; hqWPf  
read_nPos(); dWIZ37w+D  
} #_,uE9  
else /9TL&_A-T  
{ IKtiR8  
nStartPos = new long[bean.getNSplitter()]; 8q{1E];:q  
nEndPos = new long[bean.getNSplitter()]; [M<{P5q  
} H&u4v2  
Vy&f"4~  
&Ky3Jb<:Gt  
zdT->%  
} CElPU`J,\[  
t0I>5#*WU  
5@CpP-W#  
public void run() vsw7|  
{ 9DY|Sa]#=  
//获得文件长度 f^ywW[dF  
//分割文件 ^$8Vh =D  
//实例FileSplitterFetch T:dX4=z  
//启动FileSplitterFetch线程 g8rp|MOH  
//等待子线程返回 Kyyih|{  
try{ 3[,wMy"  
if(bFirst) K]%N-F>r  
{ \kfcv  
nFileLength = getFileSize(); okVp\RC  
if(nFileLength == -1) %zRiLcAT  
{ '?z9,oW{  
System.err.println("File Length is not known!"); nP5d?  
} //6^+-he  
else if(nFileLength == -2) d~vTD|Et  
{ +$(71#'y  
System.err.println("File is not access!"); d"LoK,p#  
} tru;;.lj8K  
else DXt]b,  
{ o- cj&Cv%  
for(int i=0;i<nStartPos.length;i++) X9DM ^tt  
{ ?'TA!MR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); XTIu(f|d_;  
} y @]8Ep  
for(int i=0;i<nEndPos.length-1;i++) DBLA% {05  
{ $hyqYp"/;  
nEndPos = nStartPos[i+1]; uT'-B7N  
} #: dR^zr<  
nEndPos[nEndPos.length-1] = nFileLength; C,9)V5!tP2  
} B#| Z`mZ  
} :Pj W:]  
$^!a`Xr  
u'#`yTB6b  
//启动子线程 uDpf2(>s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 87&KQ_  
for(int i=0;i<nStartPos.length;i++) RI#lI~&)  
{ }g%KvYB_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _ .-o%6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), u-8X$aJ  
nStartPos,nEndPos,i); )RpqZe/h4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oqm  
fileSplitterFetch.start(); L`<T'3G  
} `wP/Zp{Hy  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q x9>,e6+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); HGU?bJ~6o  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", iMP*]K-O  
nEndPos = " + nFileLength); |LXrGyk^  
// fileSplitterFetch[nPos.length-1].start(); Ufm(2`FQ  
\[@Q}k[  
Y\+(rC27  
//等待子线程结束 # q0Ub-  
//int count = 0; MLkL.1eGSb  
//是否结束while循环 6ctHL<^  
boolean breakWhile = false; a7XXhsZ  
?/o2#iJx  
/%N31   
while(!bStop) ws*~$x?7  
{ L?Kz P.(t+  
write_nPos(); xn%l  
Utility.sleep(500); Qx6,>'Qk'  
breakWhile = true; }:,o Y<  
GI0x>Z+  
m_{%tU;N  
for(int i=0;i<nStartPos.length;i++) A^}i^  
{ R@)'Bs  
if(!fileSplitterFetch.bDownOver) hj[+d%YZY"  
{ Oz4,Y+[#  
breakWhile = false; B[) [fE  
break; VEFwqB1l  
} bLU^1S8Z  
} Q0 uP8I}n  
if(breakWhile) 5Z4(J?n  
break; icKg7-$N  
]7XkijNb  
o(Ua",|  
//count++; 2<46jJYL'  
//if(count>4) >!HfH(is\  
// siteStop(); 3s+<    
} ~8KF<2c   
i6!T`Kau  
::3iXk)  
System.err.println("文件下载结束!"); Q:-%3)g<<  
} Dz"u8 f  
catch(Exception e){e.printStackTrace ();} ? 6yF{!F*  
} 0)6i~MglY  
IGh !d?D  
d- Z+fz  
//获得文件长度 7- *( a  
public long getFileSize() }[=xe(4]D  
{ I =tyQ`  
int nFileLength = -1; 4 ~MJ4:  
try{ Zq\RNZ}  
URL url = new URL(siteInfoBean.getSSiteURL()); 2$j Ot}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1sIy*z  
httpConnection.setRequestProperty("User-Agent","NetFox"); QK``tWLIg7  
L5-T6CD  
$'J6#Vs  
int responseCode=httpConnection.getResponseCode(); hJC p0F9O  
if(responseCode>=400) L&!g33J&  
{ +q`rz  
processErrorCode(responseCode); t+W=2w&  
return -2; //-2 represent access is error TQOg~lH  
} S:2u3th7  
`uM0,Z  
6)uPM"cO  
String sHeader; KG4#BY&^  
g~ppPAH  
n,Yr!W:h  
for(int i=1;;i++) oUKBb&&O  
{ ^hl]s?"3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (T%F!2i([U  
//Utility.log(in.readLine()); !TV_dKa  
sHeader=httpConnection.getHeaderFieldKey(i); ^.Ih,@N6  
if(sHeader!=null) niBjq#bJi  
{ 9QX ~a X  
if(sHeader.equals("Content-Length")) y'0dl "Dy\  
{ !ho5VA t  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |&0"N[t  
break; v3hQv)j)  
} St~SiTJU  
} T~wZ  
else Dh!iY0Lz  
break; },Re5W nl  
} ^sf[dr;BA  
} 3x(MvW30Lg  
catch(IOException e){e.printStackTrace ();} =jV%O$Fx  
catch(Exception e){e.printStackTrace ();} f'zU^/$rf  
xtIehr0{$I  
8XH|T^5  
Utility.log(nFileLength); Zy!)8<Cgm'  
tz0Ttu=xH  
n ]6 0  
return nFileLength; k8x&aH  
} xT=kxyu  
eF8 aB?&"  
z|DA _dG  
//保存下载信息(文件指针位置) 8[`^(O#\E  
private void write_nPos() +/~\b/  
{ ].<sAmL^  
try{ #<tWYE  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jL7MmR#y5"  
output.writeInt(nStartPos.length); S$lmEJ_  
for(int i=0;i<nStartPos.length;i++) <igx[2X  
{ fw:^Lyn9$  
// output.writeLong(nPos); \@}$Wjsl  
output.writeLong(fileSplitterFetch.nStartPos); O)RzNfI^`N  
output.writeLong(fileSplitterFetch.nEndPos); JV?RgFy  
} @aiLG wh  
output.close(); rs 1*H  
} "k6IV&0 3x  
catch(IOException e){e.printStackTrace ();} R26tQbwE  
catch(Exception e){e.printStackTrace ();} "$V8y  
} &x0TnW"g  
?CT^Zegmr  
PkCeV]`w  
//读取保存的下载信息(文件指针位置) ssr)f8R#,#  
private void read_nPos() CI~;B  
{ SJ~I r#  
try{ = @Nv:1:r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); b~haP.Cl :  
int nCount = input.readInt(); /c$Ht  
nStartPos = new long[nCount]; _#YHc[Wz  
nEndPos = new long[nCount]; q5\LdI2  
for(int i=0;i<nStartPos.length;i++) :oj) eS[Y  
{ L(1,W<kYg  
nStartPos = input.readLong(); kX ,FQG>  
nEndPos = input.readLong(); CN$A-sjZ  
} ^/d^$  
input.close(); ,^+R%7mv  
} @Y&9S)xcE  
catch(IOException e){e.printStackTrace ();} ad$Qs3)6o  
catch(Exception e){e.printStackTrace ();} P15 *VPy  
} %oCjZ"ke  
J_wz'eIb0  
oCdOC5  
private void processErrorCode(int nErrorCode) _ !^FW%  
{ DCt:EhC  
System.err.println("Error Code : " + nErrorCode);  > ^v8N  
} u$%#5_k  
hPeKQwzC0  
|phWK^   
//停止文件下载 (Y.$wMB  
public void siteStop() uQ%HLL-W/  
{ P7x?!71?L  
bStop = true; V\M!]Nnxr  
for(int i=0;i<nStartPos.length;i++) 'y M:W cN  
fileSplitterFetch.splitterStop(); ^Lfn3.M  
U_{JM`JY  
,^IZ[D>u)  
} >'|xQjLl  
} >3 .ep},  
//负责部分文件的抓取 Tvx8l m '  
**FileSplitterFetch.java 33KPo0g7  
*/ ?jn6Op  
package NetFox; TnU$L3k  
gAUQQ  
])wMUJWg2  
import java.io.*; $}UJs <-F  
import java.net.*; PKM$*_LcGI  
XsN#<"f;i  
]ifHA# z`~  
public class FileSplitterFetch extends Thread { IM5^E#-g7  
o>A%}YU  
4e#K.HU_  
String sURL; //File URL zT-"kK  
long nStartPos; //File Snippet Start Position vzm4  
long nEndPos; //File Snippet End Position Sw( H]  
int nThreadID; //Thread's ID XK/@!ud"`  
boolean bDownOver = false; //Downing is over rH:X/i;D  
boolean bStop = false; //Stop identical G~tOCp="p  
FileAccessI fileAccessI = null; //File Access interface &?`&X=Q  
/ bu<,o  
OK J%M]<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g5|\G%dOt  
{ 5'-9?-S"  
this.sURL = sURL; '*ICGKoT  
this.nStartPos = nStart; f -nC+   
this.nEndPos = nEnd; tWOze, N  
nThreadID = id; R Mt vEa  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Lm{ o=v  
} :(p rx   
\q1%d.\X  
2,Dc]oj  
public void run() lKwT5ma7  
{ JI,hy <3l0  
while(nStartPos < nEndPos && !bStop) }3_G|  
{ hPpXB:(-0  
a4.: i  
~JPzjE  
try{ }o:sx/=u_  
URL url = new URL(sURL); CgKSK0/a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1p<?S}zg@  
httpConnection.setRequestProperty("User-Agent","NetFox"); P]x+Q  
String sProperty = "bytes="+nStartPos+"-"; . mrRv8>$  
httpConnection.setRequestProperty("RANGE",sProperty); gpvj'Ri7V  
Utility.log(sProperty); y" -{6{3  
o5 XUDDi  
B[|/wHMsT}  
InputStream input = httpConnection.getInputStream(); ]b| @<E7Y  
//logResponseHead(httpConnection); 64X#:t+  
(3r,PS@Qq@  
Df3v"iCq}  
byte[] b = new byte[1024]; 6b01xu(A[  
int nRead; =F[,-B~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) J5IJy3d  
{ j5GZ;d?  
nStartPos += fileAccessI.write(b,0,nRead); L^s;kkB  
//if(nThreadID == 1) l>?vjy65  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,ToEK Id  
} +rP<m  
F|Ihq^q  
"a{f? .X.  
Utility.log("Thread " + nThreadID + " is over!"); pdiZ"pe  
bDownOver = true; G_mu7w  
//nPos = fileAccessI.write (b,0,nRead); tp2 _OQAQ  
} L1 VTq9[3  
catch(Exception e){e.printStackTrace ();} ]m>MB )9  
} &L~rq)r/&  
} 'Pu;]sC  
0^Cx`xdX:  
2Hwf:S'  
//打印回应的头信息 rNC3h"i\  
public void logResponseHead(HttpURLConnection con) L-$g& -  
{ F[Sat;Sll  
for(int i=1;;i++) M0 8Y  
{ $?{zV$r1  
String header=con.getHeaderFieldKey(i); QLG,r^  
if(header!=null) lGhUfhk  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;gV8f{X{Z  
Utility.log(header+" : "+con.getHeaderField(header)); b;l%1x9r  
else vy?YA-  
break; HI 61rXNF  
} o]U ==  
}  \RO Sd  
O 9)8a]  
]XyJ7esg  
public void splitterStop() {rLOAewr  
{ B=|sLs`I  
bStop = true; IPR396J+-  
} Yg.u8{H  
R FiR)G ,  
r+u\jZ  
} =x>k:l~s  
+Ti@M1A&  
Z5A<TC/:  
/* 8 K!a:{  
**FileAccess.java N>Y3[G+  
*//文件访问(定位,写) B,T.bgp\  
package NetFox; v^ G5 N)F  
import java.io.*; m=V2xoMw6  
;7>--_?=  
m(Ynl=c  
public class FileAccessI implements Serializable{ "(qO}&b>  
jN0v<_PJED  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r1]^#&V;MC  
RandomAccessFile oSavedFile; Rw`s O:eZ  
long nPos; gEu\X|7'  
ps{(UYM=b  
>2/zL.O  
public FileAccessI() throws IOException {r)M@@[  
{ K<tg+(3  
this("",0); o ++Hdvai  
} 7Wu2gky3  
DJ^JUVi  
3Y8 V?* 1|  
public FileAccessI(String sName,long nPos) throws IOException Kw|`y %~  
{ RI=B(0 A  
oSavedFile = new RandomAccessFile(sName,"rw"); {w++)N2sh  
this.nPos = nPos; Pt+_0OsR  
oSavedFile.seek(nPos); }1wuH  
} iVcBD0 q)  
( 9l|^w["  
j>iM(8`t1  
public synchronized int write(byte[] b,int nStart,int nLen) j3>< J  
{ K0]Wb=v  
int n = -1; <PxEl4  
try{ ZSNg^)cN  
oSavedFile.write(b,nStart,nLen); eu =2a>  
n = nLen; ra1hdf0"  
} DH%X+r  
catch(IOException e) .\ZxwD|  
{ OZ6%AUot  
e.printStackTrace (); I}X8-WFB  
} ]+8,@%="  
G r)+O  
;/.ZYTD  
return n; sIpK@BQ'  
} |8B[yr.b  
oaHBz_pg  
cQny)2k*x  
}  ulQE{c[  
>&R|t_ypw  
A{QS+fa/  
/* .1@5*xQ5O  
**SiteInfoBean.java [o~w>,a  
*/ ;3!TOY"j;e  
package NetFox; H4N==o  
:MVD83?4  
8Y9mB #X  
public class SiteInfoBean { Z+?j8(:n  
4ZIXG,@mZJ  
G9 !1Wzs  
private String sSiteURL; //Site's URL :X^B1z3X4  
private String sFilePath; //Saved File's Path Q|>y2g!  
private String sFileName; //Saved File's Name wv<"W@& 9  
private int nSplitter; //Count of Splited Downloading File nT>?}/S  
a4wh-35/  
&^EkM  
public SiteInfoBean() >g?,BK@  
{//nSplitter的缺省值为5 ()r DM@  
//default value of nSplitter is 5 V;m3=k0U  
this("","","",5); VbN]z:  
} R1nctA:  
Na=q(OKN  
_]\mh,}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'D1@+FFU0  
{ "x{S3v4Rb5  
sSiteURL= sURL; Zy'bX* s|  
sFilePath = sPath; Gqs8$[o  
sFileName = sName; ':Te#S  
this.nSplitter = nSpiltter; MV/JZ;55  
|peZ`O^ ~  
(i`DUF'#y  
} \^+sgg{  
O:#to  
kxKBI{L  
public String getSSiteURL() {PfE7KH  
{ os>|LPv4  
return sSiteURL; A81kb  
} ua0k)4|  
Hi ?],5,/  
<_NF  
public void setSSiteURL(String value) k -SUp8}g  
{ `0sa94H1[  
sSiteURL = value; 4Ld0AApncy  
} -i58FJ`B  
@A)gsDt9A  
sl)_HA7G  
public String getSFilePath() !D1F4v[c=  
{ ;1BbRnCr  
return sFilePath; a/?gp>M9  
} GE"#.J4z  
'j}%ec1  
A}$A~g5 Ap  
public void setSFilePath(String value) vHao y  
{ 4Jw0m#UN1  
sFilePath = value; /P,J);Y  
} #j@Su )+  
u%&zY97/  
JeiW z1t  
public String getSFileName() #MI}KmH  
{ h8nJ$jg  
return sFileName; '*22j ]  
} Ua( !:5q?  
Z,ag5 w`]L  
Zr`:A$  
public void setSFileName(String value) W[+E5I  
{ iX~V(~v  
sFileName = value; VN*^pAzlF  
} Y0U:i.)  
]{dg"J  
3pm;?6i6  
public int getNSplitter() qdzc"-gH`  
{ _t3n<  
return nSplitter; (0^u  
} n;4` IK|  
7IjFSN>  
YwEXTy>0  
public void setNSplitter(int nCount) '%kk&&3'  
{ 5^[V%4y>  
nSplitter = nCount; v dyu=*Y  
} %KRAcCa7  
} oT.g@kf=H  
1[/X$DyaK  
`2 Vc*R  
/* D@&0 P&  
**Utility.java e<>(c7bF  
*/ *cJ GrLC  
package NetFox; .\qZkk}2l  
<SOC  
b4i=eI8  
public class Utility { #%Uk}5;-  
G5?Dt-;I  
\Ua"gS2L  
public Utility() r( :"BQ  
{ (?D47^F &  
}`M[%]MNc  
UVA|(:  
} u-yQP@^H  
b\F(.8  
//线程睡眠 G)M9to  
public static void sleep(int nSecond) w SBDJvI  
{ kuqf(  
try{ rhsSV3iM  
Thread.sleep(nSecond); D~G24k6b3  
} ;}ileL Tl  
catch(Exception e) AMGb6enl  
{ 3u3(BY{"\F  
e.printStackTrace (); `)/G5 fB  
} N{ @B@]  
} 0Ou`& u  
|ffM6W1:  
//日志  _p<s!  
public static void log(String sMsg) MyXgp>?~T  
{ %c*azo.  
System.err.println(sMsg); |Qo;=~7  
} 5VDqx@(  
" +'E  
KW ]/u  
public static void log(int sMsg) +'Ec)7m  
{ : 2Ho  
System.err.println(sMsg); N=YRYU o  
} FY|.eY_7 {  
} nb9qVuAGU  
DJ2EV^D+P  
mp:%k\cF|  
/* ,b%T[s7  
**TestMethod.java : n 4?  
*/ ?6P P_QY  
package NetFox; QWp,(Mv:r  
VImcW;Xa  
o}C|N)'  
public class TestMethod { DG}} S 5  
v}q3_m]   
I ww.Nd2  
public TestMethod() gNY}`'~hr  
{ ///xx/weblogic60b2_win.exe p,.+i[V  
try{ i Tg?JoE2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `j{q$Y=AG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l8/ tR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2| $  
fileFetch.start(); mf ^=tZ  
} i/N4uq}'A<  
catch(Exception e){e.printStackTrace ();} [4KW64%l  
0wU8PZ Nj  
$@<qaR{t\  
} RsIR}.*  
<2Lcy&w_M  
Bvj-LT=)  
public static void main(String[] args) {%.FIw k  
{ f0]8/)  
new TestMethod(); _C$JO   
} 1bs 8fUPB3  
} B:Ec(USe  
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