http断点续传简单实现（java)

/* .O0eSp|e  
**SiteFileFetch.java 9-m_ e=jk6  
*/ /G7^l>pa  
package NetFox; y@*4*4
6v  
import java.io.*; i:
UN  
import java.net.*; C$])q`9  
(AZneK :*  
ld(_+<e  
public class SiteFileFetch extends Thread { vFJ4`Gjw(  
HI D6h!  
8q9^  
SiteInfoBean siteInfoBean = null; //文件信息Bean
$aTo9{M^  
long[] nStartPos; //开始位置 {)r[?%FMgV  
long[] nEndPos; //结束位置 4%nK0FAj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g=4P-i3  
long nFileLength; //文件长度 `O3#/1+  
boolean bFirst = true; //是否第一次取文件 `{"V(YMEV  
boolean bStop = false; //停止标志 !K*3bY`#  
File tmpFile; //文件下载的临时信息 :jTbzDqQ  
DataOutputStream output; //输出到文件的输出流 #oEtLb@O  
b4$.uLY  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;_< Yzl  
public SiteFileFetch(SiteInfoBean bean) throws IOException 502(CO>  
{ mXJG &EA  
siteInfoBean = bean; md{1Jn"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 78xiT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =u9e5n  
if(tmpFile.exists ()) U/q"F<?.c  
{ Z] cFbl\ma  
bFirst = false; ]OKKR/:  
read_nPos(); J^` pE^S  
} u8A,f}D 3  
else L~|_)4  
{ .ejC#vB{KM  
nStartPos = new long[bean.getNSplitter()]; t9W*N\  
nEndPos = new long[bean.getNSplitter()]; 2g)q (  
} p,8:(|(  
O>X!78]#K  
js)E:+{A,  
!JDyv\i}  
} I %1P:-  
CD?b.Cxai  
Us&~d"n  
public void run() vy5{Vm".4  
{ 'g)5vI~'  
//获得文件长度 TffeCaBv  
//分割文件 }/NL"0j+4  
//实例FileSplitterFetch Pvkr$ou  
//启动FileSplitterFetch线程 \3U.;}0_X  
//等待子线程返回 Pa\yp?({q  
try{ G7-.d/8|^  
if(bFirst) W}(xE?9&  
{ xWQQX  
nFileLength = getFileSize(); M _Lj
5`  
if(nFileLength == -1) uZ1G,9  
{ "[L+LPET  
System.err.println("File Length is not known!"); Jn0L_@  
} Fok`
-U  
else if(nFileLength == -2) LwQYO'X  
{ ~ebm,3?  
System.err.println("File is not access!"); 1RQM-0W,  
} /4*>.Nmb,f  
else =cR=E
{20  
{ y3'K+?4  
for(int i=0;i<nStartPos.length;i++) A:sP%c;  
{ BXl Y V"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3XjY  
} <m`Os2#  
for(int i=0;i<nEndPos.length-1;i++) ap|V}jC  
{ w01\KV  
nEndPos = nStartPos[i+1]; :(jovse\  
} 
FO|Eg9l  
nEndPos[nEndPos.length-1] = nFileLength; hdH-VR4  
} .a]av  
} '! ;Xxe5  
3AuLRI  
5&U?\YNLa  
//启动子线程 $>l65)(E\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l=&Va+K  
for(int i=0;i<nStartPos.length;i++) 1NlpOVq:)  
{ y7 W7270)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /EM=!@ka  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5=_))v<Tp  
nStartPos,nEndPos,i); 'khhn6itA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N*
hx;k9  
fileSplitterFetch.start(); cC`PmDGq  
} nfr..4,:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R?,XSJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;&RHc#1F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +JFE\>O  
nEndPos = " + nFileLength); Mg^3Y'{o  
// fileSplitterFetch[nPos.length-1].start(); 7}e{&\0=l  
%i9*2{e#~  
`Yu4h+T  
//等待子线程结束 8bEii1EM  
//int count = 0; { r8H5X  
//是否结束while循环 oJ}$ /_  
boolean breakWhile = false; <m?/yREK2  
dy0xz5N-  
y"0!7^  
while(!bStop) q&k?$rn  
{ 3)py|W%X$  
write_nPos(); Ba|76OBRJ  
Utility.sleep(500); $k3l[@;hE  
breakWhile = true; 71yf+xL  
`>}e 5  
#>\8m+h 9  
for(int i=0;i<nStartPos.length;i++) ..ht)Gex  
{ bU"2D.k  
if(!fileSplitterFetch.bDownOver) a<Ptm(,  
{ jP"='6Vrw  
breakWhile = false; a s?)6  
break; yy3-Xu4  
} >9]i#So^  
} ww{07g  
if(breakWhile) iX'#~eK*<  
break; :.EVvuXI  
ZzO.s$  
#v4q:&yKf  
//count++; lWYgIpw  
//if(count>4) -jsk-,  
// siteStop(); m3K .\3  
} {[.<BU-  
wS1zd?  
]^CNC0  
System.err.println("文件下载结束！"); )h?Pz1-W1  
} &!FWo@  
catch(Exception e){e.printStackTrace ();} ?wS/KEl=O  
} q]o^Y  
|b:91l  
, 8F(R%v  
//获得文件长度 ZzuWN&  
public long getFileSize() BIjQ8 t  
{ $T80vEi+u  
int nFileLength = -1; 2r&T.  
try{ ;v1&Rs  
URL url = new URL(siteInfoBean.getSSiteURL());
6>B_ojj:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |;_uN q9  
httpConnection.setRequestProperty("User-Agent","NetFox"); okZDxg`6  
dg]: JU  
UDz#?ZWnd  
int responseCode=httpConnection.getResponseCode(); C_DXg-a2lu  
if(responseCode>=400) :CAbGs:56  
{ ep2#a#&'  
processErrorCode(responseCode); t<2B3&o1  
return -2; //-2 represent access is error eE-@dU?  
} $]yHk  
'hi.$G_R  
=m?x|Zc_v  
String sHeader; 9nPc>O$  
^.@BD4/RPt  
hzjEO2  
for(int i=1;;i++) 2aUy1*aM  
{ V<;w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r/vRaOg>X  
//Utility.log(in.readLine()); iv/!c Mb  
sHeader=httpConnection.getHeaderFieldKey(i); noa=wy  
if(sHeader!=null) sC.aT(meJ  
{ ,s,VOyr @F  
if(sHeader.equals("Content-Length")) .-g++f(_i  
{ #{kwl|c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |H'4];>R?  
break; )tyhf(p6  
} IaLCWvHX  
} #A2)]XvY  
else jQiKof>  
break; do1aH$Iw  
} AG$S;)Yl9c  
} ]dKLzW:l  
catch(IOException e){e.printStackTrace ();} '4nR^,  
catch(Exception e){e.printStackTrace ();} *g<D p2`  
n_/_Y>{M0  
 hVB^:  
Utility.log(nFileLength); P+~{q.|._c  
jLs-
v  
~)JNevLZ  
return nFileLength; O+o1R24JI  
} SGREpOlJ+  
?x(]U+  
F#w=z/  
//保存下载信息（文件指针位置） &O5W  
private void write_nPos() @sAT#[j  
{ E$'Zd,|f=  
try{ Sb&[V>!2^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #;32(II  
output.writeInt(nStartPos.length); o7*z@R"  
for(int i=0;i<nStartPos.length;i++) ]HK|xO(  
{ Ty21-0F  
// output.writeLong(nPos); H7KcP
N(0  
output.writeLong(fileSplitterFetch.nStartPos); BQcrF{
q  
output.writeLong(fileSplitterFetch.nEndPos); jz%
%r Q(  
} i0%S6vmaS  
output.close(); 7aJLC!  
} 9o]h}Xc  
catch(IOException e){e.printStackTrace ();} N{u4  
catch(Exception e){e.printStackTrace ();} lIg;>|'Z5&  
} %/o8-N|_[  
'@ym-\,  
w7?&eF(w(  
//读取保存的下载信息（文件指针位置） &ESE?{of)  
private void read_nPos() SG{> t*E  
{ ESl-k2  
try{ u2SnL$A7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #l6L7u0~wC  
int nCount = input.readInt(); s^]F4'  
nStartPos = new long[nCount]; WvN!8*XFM  
nEndPos = new long[nCount]; y^#jM  
for(int i=0;i<nStartPos.length;i++) 8#9d
i  
{ Su0[f/4m.Q  
nStartPos = input.readLong(); $\|$ekil4  
nEndPos = input.readLong(); p1 9j  
} &!uNN|W  
input.close(); rTiW&#  
} 9nFPGIz+  
catch(IOException e){e.printStackTrace ();} a3wTcp "r  
catch(Exception e){e.printStackTrace ();} ^gwVh~j  
} ]}_@!F)  
J?WT  
gF@51K  
private void processErrorCode(int nErrorCode) 5h9`lS2  
{ AS34yM(h  
System.err.println("Error Code : " + nErrorCode); <m"yPi3TY  
} MZGN,[~)6  
{CM%QMM  
I@l'Fx  
//停止文件下载 $q]:m+Fm
 
public void siteStop() ?- 5{XrNm  
{ =rV*iLy  
bStop = true; e5bRi0  
for(int i=0;i<nStartPos.length;i++) -vcHSwGb  
fileSplitterFetch.splitterStop(); W_NQi  
)S
MS<J  
%t&5o>1C  
} AR i_m  
} fA!uSqR$V  
//负责部分文件的抓取 jlV~-}QKb7  
**FileSplitterFetch.java uUUj?%  
*/ k#8,:B2  
package NetFox; pm+_s]s,  
(c `t'e  
pJC@}z^cw  
import java.io.*; PK#; \Zw  
import java.net.*; _7(>0GY  
aHosu=NK  
TbqED\5@9w  
public class FileSplitterFetch extends Thread { bDa(@QJ-  
#{
)=%5=c  
=}Np0UP  
String sURL; //File URL )1%l$W  
long nStartPos; //File Snippet Start Position >5{Z'UWxh  
long nEndPos; //File Snippet End Position [HJ^'/bB'  
int nThreadID; //Thread's ID >yC1X|d~t  
boolean bDownOver = false; //Downing is over +$KUy>  
boolean bStop = false; //Stop identical Np4';
H  
FileAccessI fileAccessI = null; //File Access interface Hmt}@  
nYJ)M AG@  
w(O/mUDX  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {{c/:FTEU  
{ o+sb2:x  
this.sURL = sURL; fRp+-QvE  
this.nStartPos = nStart; g@!mV)c97  
this.nEndPos = nEnd; PN ,pEk|  
nThreadID = id; yUF<qB
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -s`/5kD  
} -/:N&6eRb  
S}Wj+H;  
qJ=4HlLno  
public void run() gVM9*3LH6  
{ 0oI3Fb;E  
while(nStartPos < nEndPos && !bStop) 0Fr
mZ$  
{ /3F4t V  
X\tE#c&K  
5?+ECxPt  
try{ /; ;_l2t  
URL url = new URL(sURL); h:iK;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hn
M?wn  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1b:3'E.#w  
String sProperty = "bytes="+nStartPos+"-"; vA rM.Bu>b  
httpConnection.setRequestProperty("RANGE",sProperty); jm1f,=R  
Utility.log(sProperty); 6eSc
`t&  
A`Vz5WB  
8OoKP4,;  
InputStream input = httpConnection.getInputStream(); `mTpL^f  
//logResponseHead(httpConnection); xSFY8  
VG*Tdaua~  
C~PrIM?  
byte[] b = new byte[1024]; }D_h*9  
int nRead; ~|e?@3_G  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) RG [*:ReB9  
{ \ct)/  
nStartPos += fileAccessI.write(b,0,nRead); @= f2\hU  
//if(nThreadID == 1) i3~"qbU%z[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [5 Mt,skC:  
} HS3]8nJW  
T `x:80  
TwBwqQ)t  
Utility.log("Thread " + nThreadID + " is over!"); b/IT8Cm3  
bDownOver = true; E/mp.f2!  
//nPos = fileAccessI.write (b,0,nRead); .LDK+c  
} tbHU(#~  
catch(Exception e){e.printStackTrace ();} ~1xln?Q  
} _-aQ.p ?T  
} +}H2|vP  
lub(chCE[  
_5'OQ'P2  
//打印回应的头信息 g4,>cqRkq  
public void logResponseHead(HttpURLConnection con) ?N2/;u>  
{ %~uMa  
for(int i=1;;i++) n82N@z<8]  
{ 8Fy$'Zx'  
String header=con.getHeaderFieldKey(i); 8&g|iG  
if(header!=null) T 9
Jv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); mM.-MIp  
Utility.log(header+" : "+con.getHeaderField(header)); {3@lvoDT  
else 40}qf}8n t  
break; w '?xewx  
} x<#Z3Kla  
} Q2sX7 cE  
qLkna
 
Rg3 Lo ?  
public void splitterStop() o<@b]ukl&  
{ i$HA@S  
bStop = true; P6,~0v(S  
} ~|+!xh  
}LLnJl~Z  
__HPwOCG7  
} e;KZTH;  
Mf)0Y~_:R#  
5MsE oLg  
/* K7 >Z)21  
**FileAccess.java E6(OEC%,  
*//文件访问(定位，写) }t!,{ZryE1  
package NetFox; a nK7j2  
import java.io.*; 44T>Yp09  
F3*
]3,&L  
o:E+c_^q`  
public class FileAccessI implements Serializable{ jQjtO"\JG  
rb_cm  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 jEr
/*kv  
RandomAccessFile oSavedFile; e%#(:L  
long nPos; 6x%uWZa'  
u4QPO:,a4  
0Lcd@3XL  
public FileAccessI() throws IOException vJ96qX  
{ |0 #J=am  
this("",0); [iE%P^  
} !~5;Jb>s[/  
HMsTm}d  

`OzcL  
public FileAccessI(String sName,long nPos) throws IOException TCAtb('D  
{ X;JptF^  
oSavedFile = new RandomAccessFile(sName,"rw"); '@1oM1  
this.nPos = nPos; H\]ZtSw8-  
oSavedFile.seek(nPos); *B"p:F7J|  
} 90OSe{  
t,#9i#q#  
o.yuz+  
public synchronized int write(byte[] b,int nStart,int nLen) fY3^L"R  
{ EVc Ees  
int n = -1; fD1J@57  
try{ mY9^W2:  
oSavedFile.write(b,nStart,nLen); t,$4J6  
n = nLen; vt0XCUnK  
} {KJ!rT  
catch(IOException e) 6 R}]RuFQ  
{ JSXudz5c  
e.printStackTrace (); h$[}lZDg  
} NoS|lT  
SP][xdN7  
UFnz3vc  
return n; Hts.G~~8  
} Zcq'u jU  
7PG&G5  
J7:VRf|,?(  
} l}-JtZ?[?  
p/jC}[
$v  
!yAlb#yu  
/* 0ut/ ')[  
**SiteInfoBean.java ;Awt:jF  
*/ 5B3S]@%  
package NetFox; 3@XkO  
!6yoD  
f0rM 4"1  
public class SiteInfoBean { .&O}/B  
^|yw)N]Q/  
s=0z%~H  
private String sSiteURL; //Site's URL -*8|J;  
private String sFilePath; //Saved File's Path }Z5f5q  
private String sFileName; //Saved File's Name k<p$BZ  
private int nSplitter; //Count of Splited Downloading File N"d M+  
0BF'@r";  
bt3v`q+V  
public SiteInfoBean() k}T#-Gb
 
{//nSplitter的缺省值为5 1}1.5[4d  
//default value of nSplitter is 5 :o$k(X7a  
this("","","",5); eSvS<\p  
} b77
Iw%x7  
&NbhQY`k  
GSzb  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7:7i}`O  
{ bup)cX^  
sSiteURL= sURL; Db"jzMW.  
sFilePath = sPath; _;baZ-  
sFileName = sName; O iRhp(  
this.nSplitter = nSpiltter; f9FJ:?  
&'{6_-kh  
=6FA(R|QU  
} jWHv9XtW  
Pf`HF|NI  
w|$i<OIi)  
public String getSSiteURL()
i("ok  
{ f' |JLhs  
return sSiteURL; TEQs\d  
} lYz{#UX}  
m2wGg/F5  
{%g]Ym=  
public void setSSiteURL(String value) l/?Jp+]  
{ %JUD54bBt  
sSiteURL = value; 5>z`==N)  
} 8nzDLFxp_  
OW}ny  
>bQ'*!  
public String getSFilePath() | Q0Wv8/  
{ qffVF|7  
return sFilePath; fTb&k;'LR<  
} #mhR^60,  
7lQ@I}i  
NDsF<2A4  
public void setSFilePath(String value) X2CpA;#;7l  
{ ~mAv)JK  
sFilePath = value; vjNP  
} jz CA2N%  
4%k{vo5i  
}N@8zB~X  
public String getSFileName() AlZ]UGf^  
{ %UGXgYDz  
return sFileName; `h%(ZG~  
}  ! @EZ  
&y\7
pAT\  
u!$+1fI>  
public void setSFileName(String value) 90Rz#qrI*  
{ 7$"{&T  
sFileName = value; -M\ae  
} pBo=omQV  
jtS-nQ|  
F3)w('h9c  
public int getNSplitter() gJ \CT'/  
{ ngmHiI W  
return nSplitter; ,3+#?H  
} UNK}!>HD  
.7GTL  
X*'i1)_h  
public void setNSplitter(int nCount)
-jXO9Q  
{ Epo/}y  
nSplitter = nCount; mKTE%lsH  
} 3MqyHOOv  
} mbSG  
'!\t!@I$  
tk]>\}%  
/* 1}=@';cK*  
**Utility.java <c;U 0! m  
*/ ,> %=,x
 
package NetFox; VD.wO%9?)  
?$v*_*:2h  
5/w4[d  
public class Utility { 86 $88`/2  
T?lp:~d  
qDlh6W?}k  
public Utility() V -X*e  
{ \mp2LICQg  
BIQQJLu  
-] @cUx  
} q8m[ S4Q]g  
]LbFh5;s  
//线程睡眠 zG^|W8um_  
public static void sleep(int nSecond) b8FSVV 7@  
{ J?R\qEq%  
try{ |3]#SqX  
Thread.sleep(nSecond); oy[>`qyz  
} AHB_[i'>7  
catch(Exception e) z^,P2kqK_  
{ %fJ~3mu  
e.printStackTrace (); _P}wO8  
} >;^t)6  
} /#Fz K  
x<Ac\Cx  
//日志 ]H {g/C{j  
public static void log(String sMsg) QgF2f/;!  
{ #MyF 1E  
System.err.println(sMsg); 8wH1x .  
} ^n%
9Tu  
&s0_^5B0  
H`T8ydNXa  
public static void log(int sMsg) qh~$AJ9sB  
{ +o3 ZQ9  
System.err.println(sMsg); )\PPIY>iP  
} )x&4 Q=  
} xofxE4.  
prw% )#,  
HrK7qLw7  
/* +~n"@ /  
**TestMethod.java /ka "YU  
*/ r?%,#1|$$  
package NetFox; vp|.x |@  
+*`>7m<^  
k*
u4N  
public class TestMethod { M+l~^E0Wj  
P[K42mm  
-IE=?23Do?  
public TestMethod() "2_nN]%u-  
{ ///xx/weblogic60b2_win.exe %|(Cb!ySX  
try{ =38
c}(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); p!/ *(TT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .
VA'W16  
SiteFileFetch fileFetch = new SiteFileFetch(bean); KN<KZM  
fileFetch.start(); tq.g4X ;_  
} ]|8*l]oc  
catch(Exception e){e.printStackTrace ();} Bk;/>gD  
H tx)MEZ  
p)c"xaTP#F  
} `st^i$A  
%) /Bl.{}<  
70F(`;  
public static void main(String[] args) /4>|6l=  
{ DR<=C`<4(  
new TestMethod(); Hd ${I",  
} CyKupJ.Fq  
} z{(c-7*  
点击下载更多相关资料