http断点续传简单实现（java)

/* L# 1vf  
**SiteFileFetch.java zs:7!  
*/ x=#5\t9  
package NetFox; .8!0biS  
import java.io.*; FxX3Pq8h  
import java.net.*; `VE&Obp[  
P$ef,ZW"  
Hu7zmh5
FF  
public class SiteFileFetch extends Thread { [\ YP8^..  
rM=A"  
+|<&#b0Xd  
SiteInfoBean siteInfoBean = null; //文件信息Bean 0Ida]H  
long[] nStartPos; //开始位置 Hc%\9{zH  
long[] nEndPos; //结束位置 =M#?*e  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -b}S3<15@  
long nFileLength; //文件长度 X4G55]D$>  
boolean bFirst = true; //是否第一次取文件 %Nl(Y@dD*  
boolean bStop = false; //停止标志 @e0
skc  
File tmpFile; //文件下载的临时信息 [s{:}ZuKc  
DataOutputStream output; //输出到文件的输出流 f4T0Y["QA  
%pkq ?9  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） I?g__u=n~  
public SiteFileFetch(SiteInfoBean bean) throws IOException @qy*R'+  
{ :+Ax3  
siteInfoBean = bean; _5w?v~65  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
N:[;E3?O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5)5bt q)[  
if(tmpFile.exists ()) M9g\/]Io;  
{ "4hpU]4j  
bFirst = false; cEjdImAzU  
read_nPos(); $#FlnM<=  
} 97wy;'J[u  
else WbWW=(N'd  
{ MxEAs}MDv  
nStartPos = new long[bean.getNSplitter()]; %=8(B.I!  
nEndPos = new long[bean.getNSplitter()]; 2\\3<  
} @h$0S+?:  

[(F<|f:n  
dd7nO :]  
F'$S!K58  
}
$jh>zf  
)9*3^v  
EJ ~kZ3  
public void run() Q9xx/tUW  
{ )$h9Y   
//获得文件长度 XJ~l5}y ]  
//分割文件 nSQ}yqM)  
//实例FileSplitterFetch sLi//P?:t  
//启动FileSplitterFetch线程
&N_c-@2O  
//等待子线程返回 7QiCZcb\  
try{ xyjVdD\  
if(bFirst) nCMa$+  
{ z12But\<  
nFileLength = getFileSize(); X5
|/s::u  
if(nFileLength == -1)  5vF}F^  
{ qZsddll  
System.err.println("File Length is not known!"); ~)a;59<$  
} 0s9z @>2  
else if(nFileLength == -2) k)K-mD``U  
{ c_bVF 'Bz  
System.err.println("File is not access!"); q[OTaSQ~u^  
} .7gE^  
else %"[dGB$S  
{ X/8iJ-KB  
for(int i=0;i<nStartPos.length;i++) Te@6N\g  
{ SslY]d]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); */^2RZg|W  
} 6_5d  
for(int i=0;i<nEndPos.length-1;i++) t?nc0;Q9,@  
{ rYFau1  
nEndPos = nStartPos[i+1]; <h_P+ nz  
} TBKd|D'H  
nEndPos[nEndPos.length-1] = nFileLength; )|x%o(n  
} _|  
} -+=:+LhSMb  
,;iBeqr5  
@fH&(@  
//启动子线程 ](=wlq)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4JZHjf0M6  
for(int i=0;i<nStartPos.length;i++) s>VEuLY*  
{ Sj{ia2AE_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %|(?!w7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C9F+e  
nStartPos,nEndPos,i); s9rtXBJP  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #>:(#^Uu  
fileSplitterFetch.start(); CSL{Q  
} z34>,0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^~6]0$yJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !b]2q%XM  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "?SOBA!vy  
nEndPos = " + nFileLength); jfY{z=*]u  
// fileSplitterFetch[nPos.length-1].start(); q|u8CX  
\_*MJ)h)X  
-[pCP_`)u  
//等待子线程结束 lgonR  
//int count = 0; RzzFhU#r  
//是否结束while循环 W8,tl>(  
boolean breakWhile = false; SE^b0ZV*x  
},fo+vRM  
u.
kY
p  
while(!bStop) 0/:=wn^pg  
{ &oeN#5Es8C  
write_nPos(); II-$WJy  
Utility.sleep(500); B8UZ9I$n  
breakWhile = true; inBPT~
y  
0Ox|^V  
]`@]<6  
for(int i=0;i<nStartPos.length;i++) *F szGn<  
{ .'S^&M/$  
if(!fileSplitterFetch.bDownOver) Aa`MK$29F  
{ ^'7C0ps+A  
breakWhile = false; \+{t4Im  
break; +qdIj] v  
} N2tkCkl^x9  
} dm2CA0   
if(breakWhile) e$Bf[F#;-  
break; :6W^ S/pf  
7V=MRf&xQ  
EDHg'q  
//count++;  )8$:DW;  
//if(count>4) {x[;5TM  
// siteStop(); X7H'Uk9:  
} ;V~rWzKM(  
kG$E tE#  
b4v(k(<  
System.err.println("文件下载结束！"); jJUGZVM6)  
} B [+(r  
catch(Exception e){e.printStackTrace ();} 1 Itil~  
} v\%B  
rv}mD  
3ximNQ}S  
//获得文件长度 9k\)tWe  
public long getFileSize() ut$,?k!M  
{ Hwp{<  
int nFileLength = -1; (LRM~5KVg  
try{ 7$ =Y\P  
URL url = new URL(siteInfoBean.getSSiteURL()); ~{4n}*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y$`eg|$  
httpConnection.setRequestProperty("User-Agent","NetFox"); qX5yN| A4  
*#1y6^  
fVDDYo2\  
int responseCode=httpConnection.getResponseCode(); 2$ |]Vj*Zs  
if(responseCode>=400) 3I"NI.>*  
{ N-2([
v  
processErrorCode(responseCode); FjZc#\^9  
return -2; //-2 represent access is error V06CCy8n  
} `ke3+%uj o  
D0/DI  
dn
ZzA  
String sHeader; J3e
:Y!  
/2;dH]o0  
]cm6 |`pz  
for(int i=1;;i++) 3`A>j"  
{ |(V?,^b^ro  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &~~aAg  
//Utility.log(in.readLine()); +Qh[sGDdY  
sHeader=httpConnection.getHeaderFieldKey(i); F$Im9T6  
if(sHeader!=null) D XV@DQ  
{ 7}4'dW.  
if(sHeader.equals("Content-Length")) <nWKR,  
{ , 3X: )  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N]14  
break; ZfPd0 p  
} -AjH}A[!  
} +T0op4  
else O' +"d%2'  
break; sM9FE{,mx  
} qoj^_s6  
} bMN@H\Ek  
catch(IOException e){e.printStackTrace ();} D|d4:;7  
catch(Exception e){e.printStackTrace ();} 7
\A4vUI3  
*Jvxs R'a1  
.u1X+P7  
Utility.log(nFileLength); ]~-*hOcQ4  
_1^8xFe2  
mZ~qG5@/F  
return nFileLength; X^}A*4j  
} Rj[hhSx 2  
&<,SV^wag  
]^=|Zd-  
//保存下载信息（文件指针位置） qib7Z]j  
private void write_nPos() KRYcCn  
{  fb\DiKsW  
try{ ugYw<  
output = new DataOutputStream(new FileOutputStream(tmpFile));  ep+  
output.writeInt(nStartPos.length); (1CJw:  
for(int i=0;i<nStartPos.length;i++) ?Z q_9T7  
{ 4% HGMr  
// output.writeLong(nPos); AL$W+')  
output.writeLong(fileSplitterFetch.nStartPos); ^=EjadVQ  
output.writeLong(fileSplitterFetch.nEndPos); 'p%=<0vrr  
} ZJ;LD*  
output.close(); *'D=1{WZ!  
} gH %y  
catch(IOException e){e.printStackTrace ();} w |_GV}#_  
catch(Exception e){e.printStackTrace ();} o+nG3kRD  
} xXX/]x>  
><;Q@u5~  
kt^yj"C>  
//读取保存的下载信息（文件指针位置） D+Cm<ZT~  
private void read_nPos() 5h0>!0  
{ R A:jzht  
try{ !(Krf  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (;aB!(_  
int nCount = input.readInt(); KP3n^ $~  
nStartPos = new long[nCount]; x97L6!  
nEndPos = new long[nCount]; W9Nmx3ve  
for(int i=0;i<nStartPos.length;i++) JqEW=5  
{ 9)+@0fG)  
nStartPos = input.readLong(); -G9|n#zCU  
nEndPos = input.readLong(); G.g|jP'n  
} 6vto++  
input.close(); y&"!m}  
} #EbGL])F}  
catch(IOException e){e.printStackTrace ();} s5l3V2k  
catch(Exception e){e.printStackTrace ();} c-kA^z{f  
} GnFs63  
wW:7y>z)  
Wta]BX  
private void processErrorCode(int nErrorCode) ~-TOsRvxR  
{ 5IW8=$k~.)  
System.err.println("Error Code : " + nErrorCode); *8bK')W  
} .NJ|p=fy  
9Bz0MUbrLl  
@6 /yu>%  
//停止文件下载 xCWz\-;  
public void siteStop() %aU4,j^],o  
{ xjo;kx\y^  
bStop = true; )6{< i5nJ\  
for(int i=0;i<nStartPos.length;i++) Nt]qVwUm'Y  
fileSplitterFetch.splitterStop(); #;[Bl=3(  

q-nER<  
G?`-]FMO  
} ["y6b*;x  
} 9#7J:PfZ<  
//负责部分文件的抓取 nnw
JYEi  
**FileSplitterFetch.java W|MWXs5'1*  
*/ [4*1}}gW%5  
package NetFox; J8?2R^;{  
n9%]-s\Hn  
>"v9iT  
import java.io.*; pMR,#[U<  
import java.net.*; 1<.5ub*i4  
{uU 2)5i2-  
$ rUSKm#  
public class FileSplitterFetch extends Thread { ACg;CTBb  
prtK:eGe2  
tdep|sD  
String sURL; //File URL A%u_&a}  
long nStartPos; //File Snippet Start Position m:uPEpcU  
long nEndPos; //File Snippet End Position +dk fcG  
int nThreadID; //Thread's ID [:h5}  
boolean bDownOver = false; //Downing is over ;HNq>/{  
boolean bStop = false; //Stop identical c 6"Ib)  
FileAccessI fileAccessI = null; //File Access interface ;au*V5a%  
,zhJY ?sk  
VfSj E.|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e_.Gw"/Yl  
{ 6)qp*P$L  
this.sURL = sURL; rh!;|xB|+  
this.nStartPos = nStart; #(KDjnP[  
this.nEndPos = nEnd; HeLG?6  
nThreadID = id; tIc 7:th  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P
T'MNH  
} >oGiIYq  
_V2xA88
 
X|}2_B  
public void run() j.m(ltGh  
{ _Mk7U@j+9  
while(nStartPos < nEndPos && !bStop) +D&Pp0xe  
{ o(!@7Lqq  
a~PK pw2%  
AiP!hw/V$  
try{ ;W]\rft[  
URL url = new URL(sURL); V
wyVEZt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *$,:m  
httpConnection.setRequestProperty("User-Agent","NetFox"); m&*JMA;^  
String sProperty = "bytes="+nStartPos+"-"; d%_OT0Ei  
httpConnection.setRequestProperty("RANGE",sProperty); I|9 SiZ0  
Utility.log(sProperty); ~g6 3qs  
g^7MM
lY%  
",yc0 2<  
InputStream input = httpConnection.getInputStream();
`JB?c  
//logResponseHead(httpConnection); a0=

WfeT  
T 2F6)e  
,WDX(  
byte[] b = new byte[1024]; %eg+F  
int nRead; H,QTYXi "  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d\]Yk]r  
{ ;Hmp f0$  
nStartPos += fileAccessI.write(b,0,nRead); wSEWwU[  
//if(nThreadID == 1) 0hY{<^"Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `d\r;cE%lm  
} W$0^(FH[  
W3H+.E  
HCWNo  
Utility.log("Thread " + nThreadID + " is over!"); +s++7<C  
bDownOver = true;
S >yLqPp  
//nPos = fileAccessI.write (b,0,nRead); [
sF(#Y:I  
} G2Vv i[c  
catch(Exception e){e.printStackTrace ();} M|,mr~rRG  
} 58 bCUh#uw  
} 3djC;*,9,  
xtfBfA  
i,IB!x  
//打印回应的头信息 x/!5K|c  
public void logResponseHead(HttpURLConnection con) gNYqAUG5  
{ UC HZ2&  
for(int i=1;;i++) 3]RyTQ
 
{ +Q$h ]^>~  
String header=con.getHeaderFieldKey(i); tM4Cx  
if(header!=null) TX=yPq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); T4)fOu3]  
Utility.log(header+" : "+con.getHeaderField(header)); nUS| sh  
else ) ZfdQ3  
break; y5r4+2B  
} T 20&F  
} Fqy\CMC  
t.p~\6
Yi  
5Xn.CBd]  
public void splitterStop() ]\ !5}L  
{ R:X0'zeRr  
bStop = true; `h:34RC;  
} i|`dWOVb  
]:>,A@7  
i4JqT\q  
} Gg Jf7ie4  
+M' H0-[  
_{<seA  
/* /!h;c$  
**FileAccess.java VTy9_~q  
*//文件访问(定位，写) Xpe)PXb  
package NetFox; )R`xR,H  
import java.io.*; [AMAa]^  
I$q]. B  
s\!>"J bAQ  
public class FileAccessI implements Serializable{ 3?2 FP|G8  
oND@:>QBF
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `F<jLU^3  
RandomAccessFile oSavedFile; Guz"wY  
long nPos; KlRr8G!Z  
v~QHMg  
h8Yx#4  
public FileAccessI() throws IOException (aOv#Vor]%  
{ 8
YC_3Yi%  
this("",0); 4=<tWa|@9  
} 1`ayc|9BR  
q$I:`&  
hn#1%p6t  
public FileAccessI(String sName,long nPos) throws IOException !;?+>R)h  
{ %_!bRo  
oSavedFile = new RandomAccessFile(sName,"rw"); =UUU$hq2  
this.nPos = nPos; MxT-1&XL  
oSavedFile.seek(nPos); |$?bc3  
} _ODbY;M  
,eTU/Q>{,&  
C74a(Bk}H  
public synchronized int write(byte[] b,int nStart,int nLen) /c uLc^(X  
{ lOtDqb&  
int n = -1; 0a80 LAK  
try{ th;{V%:LW  
oSavedFile.write(b,nStart,nLen); *98$dQR$  
n = nLen; 6I@h9uIsze  
} n{6G"t:^l  
catch(IOException e) |*}4 m'c  
{ 15o9 .   
e.printStackTrace (); H\TI[JPAl  
} ")d`dj\o  
Djg,Lvhm  
&Z`#cMR{H  
return n; hCC<?5q  
} #O+),,WS  
)c `7( nY  
7(pF[LCF  
} I:mr}mv=i  
C.FI~Z  
."9];)2rx  
/* B)0i:"q  
**SiteInfoBean.java {{QELfH2  
*/ #{?qNl8F*J  
package NetFox; zAiXo
__x  
rx]  @A  
ax(c#
 
public class SiteInfoBean { V#iPj'*   
V,%=AR5
 

S:OO0<W  
private String sSiteURL; //Site's URL  5~>z h  
private String sFilePath; //Saved File's Path ZzSz%z_sE  
private String sFileName; //Saved File's Name $m/)FnU/  
private int nSplitter; //Count of Splited Downloading File
ZjF 4v  
oz,e/v8~  
C#Na&m  
public SiteInfoBean() zx)z/
1  
{//nSplitter的缺省值为5 +mn,F};  
//default value of nSplitter is 5 Le\?+h42>  
this("","","",5); PpAu!2lt9  
} "vOwd.(?N  
LU={")TdQ  
-4 SY=NC_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @0/+_2MH-  
{ P
K`D8)=u  
sSiteURL= sURL; t+!$[K0/  
sFilePath = sPath; hpD!2 K3>  
sFileName = sName; ^zQ/mo,Z  
this.nSplitter = nSpiltter; `Tv[DIVW  
"$YJX1u3  
[D\k^h  
} ]GW]dM  
Zcx`SC-0  
e]zBf;9J  
public String getSSiteURL() C$XU%5qi  
{ tM'P m  
return sSiteURL; =Jyu4j *}  
} iMDM1}b  
~kEI4}O  
uFinv2Z'  
public void setSSiteURL(String value) ~v|>xqWV  
{ `u&Rsz&^  
sSiteURL = value; @U& QI*  
} #Up86(Z  
Al}B34.uh  
|xdsl,  
public String getSFilePath() -C(crn  
{ v0H@Eg_  
return sFilePath; SC)g^E#  
} 6[ j.@[t  
Ju1D =b  
P*3BB>FO   
public void setSFilePath(String value) j~[z2tV  
{ |}Nn!Sj>#;  
sFilePath = value; #."-#"0  
} CTq&-l:f  
:&V h?  
?kbiMs1;u  
public String getSFileName() c7x~{V8  
{ 4R1<nZ"e~  
return sFileName; vunHNHltW0  
} Lr~=^{  
(ROY?5 @c  
Y[}>CYO  
public void setSFileName(String value) #W4dkCd(pF  
{ pZqq]mHK  
sFileName = value; U`,6 * MS  
} A>o*t=5  
5K>3My
#  
~j}cyHg  
public int getNSplitter() EyJJ0  
{ (X\@t-8  
return nSplitter; JfLqtXF[&"  
} l5!|I:
/*;  
eD?tLj  
Q ayPo]O  
public void setNSplitter(int nCount) OEA&~4&{7  
{ 'vbsvT  
nSplitter = nCount; }ppN k:B  
} X86O lP)eX  
} Jh,]r?Bd  
R3gdLa.  
.WA-&b_  
/* CQF:Rnb  
**Utility.java 5Ha9lM2gh  
*/ 5q3JI  
package NetFox; RO+GK`J  
Lo{ E:5q  
G|!Tj X7s  
public class Utility { |"ls\ 7  
Yvw(tj5_5  
ayR-\mZ  
public Utility() &^ 1$^=  
{ ,8U&?8l  
snE8 K}4  
[=6]+V83M  
} y\4L{GlBM  
)~)J?l3{  
//线程睡眠 *2pt%eav  
public static void sleep(int nSecond) Dp,L/1GQ8  
{ X( \AB  
try{ o=1Uh,S3R  
Thread.sleep(nSecond); B+P(M!m3  
} 4gI/!,J(b  
catch(Exception e) 6m*QX+  
{ y-'$(x
 
e.printStackTrace (); ]7W&JKmA&  
} :~&~y-14  
} FH?U(-  
\)#kquH/l  
//日志 at#ja_ hd  
public static void log(String sMsg) ?~BC#B\>o  
{ Gw/Pk4R  
System.err.println(sMsg); S 6@u@C  
} 4KhV|#-;k  
i1ixi\P{0  
)B"jF>9)[  
public static void log(int sMsg) ]sf7{lVT  
{ :%tU'w  
System.err.println(sMsg); ?pW`cFLDHF  
} GZN ^k+w  
} 6M @[B|Q(  
n4;.W#\  
}aa'\8  
/* ,>bh$|  
**TestMethod.java SA&Rep^  
*/ kJ'
!r  
package NetFox; :;t:H] f  
0gW"i&7c  
q6McGHT  
public class TestMethod { dyz2.ZY~2  
EizKoHI-z  
(9''MlGd%  
public TestMethod() Q|S.R1L^  
{ ///xx/weblogic60b2_win.exe \FQRNj?'_  
try{ PS)4 I&;U  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pnl{&<$C%C  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jwc
)Lj}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E:UW#S%A f  
fileFetch.start(); fiK6@,  
} }"nItcp.1  
catch(Exception e){e.printStackTrace ();} YqhAZp<  
'nzg6^I7g  
$p1(He0 2  
} $Xv*,Bq  
nsu@h  
Xb|:vr\v  
public static void main(String[] args) B]nEkO'a:  
{ Y071Y:  
new TestMethod();  ~^NtO  
} u1J0$  
} py$Q  
点击下载更多相关资料