http断点续传简单实现（java)

/* ^/k*h J{  
**SiteFileFetch.java ;GD]dW#  
*/ 8JUwf  
package NetFox; 4`=mu}Y2  
import java.io.*; |+"(L#wk  
import java.net.*; +W+|%qM,\  
{Hk}Kow  
xd0 L{ue.  
public class SiteFileFetch extends Thread { i{qgn%#}Y  
{fp[BF  
^dxTm1Z  
SiteInfoBean siteInfoBean = null; //文件信息Bean 8a"%0d#  
long[] nStartPos; //开始位置 xe$_aBU  
long[] nEndPos; //结束位置 ,"0:3+(8;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 EB|}fz  
long nFileLength; //文件长度 S5EK~#-L[  
boolean bFirst = true; //是否第一次取文件 ?Ss!e$jf  
boolean bStop = false; //停止标志 ]J]h#ZH
x  
File tmpFile; //文件下载的临时信息 PmM3]xVzd  
DataOutputStream output; //输出到文件的输出流 kAGBdaJ"  
Jfl!#UAD|n  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +qdEq_m  
public SiteFileFetch(SiteInfoBean bean) throws IOException <=C?e<Y  
{ @=f\<"$vt  
siteInfoBean = bean; 3irl (;v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); '/%H3A#L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H" 7u7l  
if(tmpFile.exists ()) k~z Iy;AZ  
{ g#E-pdY  
bFirst = false; pI<f) r  
read_nPos(); l}M!8:UzU  
} o[D9I hs  
else Z<{QaY$"  
{ dUdT7ixo  
nStartPos = new long[bean.getNSplitter()]; _PR4`C*  
nEndPos = new long[bean.getNSplitter()]; 11;zNjD|  
} r#mx~OVkk  
(&x['IR  
bi;1s'Y<D  
g< .qUBPKX  
} Rbv;?'O$L  
P{^6v=8)  
o#1 $q`Z  
public void run() Eu04e N  
{ see
BS/%  
//获得文件长度 ZqO^f*F>h  
//分割文件 18:%~>.!  
//实例FileSplitterFetch 0+b1vhQ  
//启动FileSplitterFetch线程 #C@FYOf*  
//等待子线程返回 ,5<Cd,`*  
try{ )@bQu~Y  
if(bFirst) 3"\lu?-E  
{ "U"Z 3*  
nFileLength = getFileSize(); |#N&akC  
if(nFileLength == -1) \Y}8S/]  
{ mpJ#:}n  
System.err.println("File Length is not known!"); Wo=jskBrQ  
} `Ryp% Bn  
else if(nFileLength == -2) <1M-Ro?5k  
{ ;t`&n['N>  
System.err.println("File is not access!"); U:_^#\p  
} "g8M
0[7e3  
else r",GC]  
{ Uf+%W;}  
for(int i=0;i<nStartPos.length;i++) Q&bM\;Ml  
{ y"wShAR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Pk)1WK7E  
} )w%!{hn  
for(int i=0;i<nEndPos.length-1;i++) R*r#E{!V;  
{ S|+o-[e8O  
nEndPos = nStartPos[i+1]; 4H]L~^CD  
} $PHvA6D  
nEndPos[nEndPos.length-1] = nFileLength; .#pU=v#/[  
} UW EV^ &"x  
} t\ewHZG"  
VY\&8n}e(  
SasJic2M  
//启动子线程 R{T$[$6S  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; UFuX@Lu0  
for(int i=0;i<nStartPos.length;i++) $iz|\m  
{ _:27]K:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5/Uy{Xt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0{R=9wcc  
nStartPos,nEndPos,i); '2^Q1{ :\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6)Lk-D  
fileSplitterFetch.start(); tIgN$BHR>  
} Pgea NK5Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cYt!n5w~W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pz>>)c`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4HA<P6L  
nEndPos = " + nFileLength);
A3@6N(  
// fileSplitterFetch[nPos.length-1].start(); cExS7~*  
*;*r8[U}q  
3m)y|$R  
//等待子线程结束 um0N)&iY  
//int count = 0; P";'jVcR  
//是否结束while循环 wD)XjX  
boolean breakWhile = false; ~e@z;]CiY  
TRq6NB  
yz8jw:d^-  
while(!bStop) ')3 bl3:  
{ gB'6`'  
write_nPos(); Q'0d~6n&{  
Utility.sleep(500); 6N
HX2Ja  
breakWhile = true; &.?'i1!  
XOS[No~  
@MCg%Afw  
for(int i=0;i<nStartPos.length;i++) ,nm*q#R,0  
{ '."ed%=MC  
if(!fileSplitterFetch.bDownOver) 
3$9W%3  
{ @s2y~0}#  
breakWhile = false; 'q:`? nJ^  
break; :6\qpex  
} ]?[fsdAQW  
} e^D]EA]%  
if(breakWhile) LSr]S79N1  
break; ~R92cH>L  
,\%c^,HLJ  
)I.$=s  
//count++; [HZv8HU|  
//if(count>4) 6,{$J  
// siteStop(); Q$Q([Au  
} ,DkNLE  
6~w@PRy  
N//KPh  
System.err.println("文件下载结束！"); 6V01F8&w  
} u:_,GQ )\  
catch(Exception e){e.printStackTrace ();} gSQJJxZ{?  
} @6T/Tdz  
g7W"  
>V}#[/n  
//获得文件长度 v^ VitLC  
public long getFileSize() :G%61x&=Zc  
{ QB'aON\S  
int nFileLength = -1; @2 fg~2M1  
try{ ~FG]wNgS  
URL url = new URL(siteInfoBean.getSSiteURL()); :X (=z;B;N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G*P#]eO  
httpConnection.setRequestProperty("User-Agent","NetFox"); X_\otVh(D  
kL"2=7m;  
'$%l7  
int responseCode=httpConnection.getResponseCode(); 4@# `t5H  
if(responseCode>=400) HCC#j9UN6  
{ @r/nF5  
processErrorCode(responseCode); oEZdd#*;  
return -2; //-2 represent access is error &FN.:_E  
} ckE-",G  
F@B]et7  
?+}_1x`  
String sHeader; 'AS|ZRr/  
,wAF:7'  
+ @s"zp;F  
for(int i=1;;i++) Qjv}$`M  
{ 9m~p0ILh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *wB1,U{  
//Utility.log(in.readLine()); QE`
bSI  
sHeader=httpConnection.getHeaderFieldKey(i); n8ZZ#}Nhg  
if(sHeader!=null) q'Tf,a  
{ _.Uh)-yR  
if(sHeader.equals("Content-Length")) %aVq+kC h  
{ x-&@wMqkc  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QX'qyojxN  
break; n[Y~]  
} 5uj?#)N  
} IKilr'  
else 6zuTQ^pz  
break; ou{2@"  
} ={@6{-tl  
} D7Q$R:6|  
catch(IOException e){e.printStackTrace ();} >jc [nk  
catch(Exception e){e.printStackTrace ();} +*/Zu`kzX  
0[?Xxk}s0  
?QdWrE_  
Utility.log(nFileLength); PP33i@G  
57  
[~c|mOk  
return nFileLength; a'yK~;+_9  
} \\B(r  
XYOC_.f1  
VY=jc~c]v  
//保存下载信息（文件指针位置） h^(*Tv-!  
private void write_nPos() CU2*z(]&  
{ _H7x9 y=  
try{ #( 146  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |~mOfuQb  
output.writeInt(nStartPos.length); ra gXn  
for(int i=0;i<nStartPos.length;i++) O`t&ldU  
{ fdi\
hg^x  
// output.writeLong(nPos); p}pjfG  
output.writeLong(fileSplitterFetch.nStartPos); eF-."1  
output.writeLong(fileSplitterFetch.nEndPos); !9VY|&fHe  
} .~~T\rmI  
output.close(); "CQa.%  
} 7CURhDdk  
catch(IOException e){e.printStackTrace ();} m'=Crei  
catch(Exception e){e.printStackTrace ();} ^EQ<SCh  
} F8,RXlGfA[  
,G?WAOy,  
nBSYsp{  
//读取保存的下载信息（文件指针位置） tpQ(g%  
private void read_nPos() YWO)HsjP  
{ bI9~jWgGp  
try{ .:%0E`E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Zaf:fsj>  
int nCount = input.readInt(); jZkcBIK2  
nStartPos = new long[nCount]; FxWSV|Z  
nEndPos = new long[nCount]; 1FL~ndJs  
for(int i=0;i<nStartPos.length;i++) LxSpctiNx  
{ !")tU+:  
nStartPos = input.readLong(); 6Vnsi%{  
nEndPos = input.readLong(); Nkth>7*  
} W/bQd)Jvk  
input.close(); Ee%%d  
} C]`$AqKl  
catch(IOException e){e.printStackTrace ();} qvKG-|j  
catch(Exception e){e.printStackTrace ();} z3m85F%dR  
} u?<%q!  
|a`Sc%  
[ =9T*Sp  
private void processErrorCode(int nErrorCode) goOCu  
{ u5b|#&-mX  
System.err.println("Error Code : " + nErrorCode); `w7v*h|P  
} Ma']?Rb`  
S3*`jF>q  
Hc$O{]sq  
//停止文件下载 a;qryUyG  
public void siteStop() =M[bnq*\  
{ e>7>j@(K]  
bStop = true; jB Z&Ad@e  
for(int i=0;i<nStartPos.length;i++) Q}K"24`=  
fileSplitterFetch.splitterStop(); s %``H`  
!v_|zoCEj  
Ru!iR#s)!  
} H0gbSd+  
} 7p16Hv7y~  
//负责部分文件的抓取 IT7
wT+  
**FileSplitterFetch.java J~zUp(>K  
*/ */^q{PsN  
package NetFox; c&
?m>2^6  
/}fHt^2H  
8hz^%vm  
import java.io.*;
G kl71VX  
import java.net.*; H.|#c^I  
GxI!{oi2  
FF(#]vz'  
public class FileSplitterFetch extends Thread { `O!X((  

/
hH  
lH x^D;m6  
String sURL; //File URL  Rn(ec  
long nStartPos; //File Snippet Start Position s_OF(o  
long nEndPos; //File Snippet End Position ~IfJwBn-i  
int nThreadID; //Thread's ID tGh~!|P  
boolean bDownOver = false; //Downing is over aFb==73aLw  
boolean bStop = false; //Stop identical .B]MpmpK  
FileAccessI fileAccessI = null; //File Access interface IS{wtuA.  

pnowy;  
~Z?TFg  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Xq]w<$  
{ FaQe_;  
this.sURL = sURL; [P=Jw:E  
this.nStartPos = nStart; ~hnQUS`A  
this.nEndPos = nEnd; ll<Xz((o  
nThreadID = id; ^w@%cVh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *yt=_Q  
} FxtQXu-g  
F|o:W75  
iohop(LZ  
public void run() T@:Wp4>69  
{ Yz/md1T$  
while(nStartPos < nEndPos && !bStop) +`7i'ff  
{ U9:zVy  
\K{0L  
9N%We|L,c  
try{ h-#6av:  
URL url = new URL(sURL); Ic"ybj`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Pw7]r<Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); u<6<iD3y  
String sProperty = "bytes="+nStartPos+"-"; J!v3i*j\  
httpConnection.setRequestProperty("RANGE",sProperty); iwZPpl";  
Utility.log(sProperty); F3v!AvA|  
x=hiQ>BIO0  
Qcq`libK  
InputStream input = httpConnection.getInputStream(); nJG U-Z  
//logResponseHead(httpConnection); b8`)y<7  
&
I+5  
<;eW=HT+uq  
byte[] b = new byte[1024]; MSQEO4ge  
int nRead; g:'xae/]S  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 
3nIU1e  
{ nA-.mWD_C  
nStartPos += fileAccessI.write(b,0,nRead); ]YnD  
//if(nThreadID == 1) \=?a/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fNli  
} \}u Y'F  
7 S#J>*  
UqFO|r"M  
Utility.log("Thread " + nThreadID + " is over!"); E:sf{B'&  
bDownOver = true; BOb">6C  
//nPos = fileAccessI.write (b,0,nRead); JgKO|VO  
} xjuN
-  
catch(Exception e){e.printStackTrace ();} ENl)Ts`y  
} JIEK*ui  
} uB]7G0g:  
$<dH?%!7  
;v)JnbsH}  
//打印回应的头信息 ld|5TN1  
public void logResponseHead(HttpURLConnection con) {3>$[bT  
{ fnjPSts0  
for(int i=1;;i++) F 5bj=mI  
{ VuhGx:Xl  
String header=con.getHeaderFieldKey(i); oo/qb`-6  
if(header!=null) vsCCB}7\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o lR?n(v  
Utility.log(header+" : "+con.getHeaderField(header)); q 6:dy  
else Uu10)/.LC  
break; UAkT*'cB  
} !=*g@mgF  
} T]f ;km  
9N#_(uwt  
0rQMLx  
public void splitterStop() E<{R.r  
{ <.x{|p  
bStop = true; Thp[+KP>  
} p,5i)nEFj  
Go`vfm"S  
e8>})  
} qTRsZz@  
,8S/t+H  
9Z@hPX3.  
/* n$MO4s8)  
**FileAccess.java O40?{v'  
*//文件访问(定位，写) lK?uXr7^  
package NetFox;
LiC*@W  
import java.io.*; YiXk5B0Uh  
^]>O;iB?  
#5Qpu  
public class FileAccessI implements Serializable{ |PvPAPy)uu  
vONasD9At  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p,EQ#Ik  
RandomAccessFile oSavedFile; 9%o32eo,3  
long nPos; +xh`Q=A  
L4@K~8j7  
B?eCe}*f;B  
public FileAccessI() throws IOException 0JWDtmK=C  
{ !j
8FIY'[  
this("",0); wjU9ZGM  
} GL>O4S<`  
afCW(zHp  
bWjc'P6rx  
public FileAccessI(String sName,long nPos) throws IOException ]g#:KAqz  
{ fbyd"(V8r  
oSavedFile = new RandomAccessFile(sName,"rw"); 2 ~dE<}  
this.nPos = nPos; a kkNI3  
oSavedFile.seek(nPos); |0&IXOW"XF  
} v^sv<4*%  
paA(C|%{  
AwCcK6N1  
public synchronized int write(byte[] b,int nStart,int nLen) 6iry6wcHm  
{ HDz5&7* .  
int n = -1; f$o_e90mu  
try{ vz@A;t  
oSavedFile.write(b,nStart,nLen); w49t9~  
n = nLen; Fx]WCQo  
} #>a\>iKQ2q  
catch(IOException e) S^JbyD_yoh  
{ 6gU96Z  
e.printStackTrace (); <.%4 ! }f8  
} Ij7p'a  
rP'me2 B  
=ke2;}X  
return n; =1@u  
} 2,y|EpG#  
'NbHa!  
G~]Uk*M q  
} >1X|^  
:;v~%e{k  
[@_Jj3`4  
/* cRC6 s8  
**SiteInfoBean.java +X\FBvP&  
*/ 3xy<tqfr  
package NetFox; V%t.l  
DcS+_>a\{l  
lwR<(u31e  
public class SiteInfoBean { ]]HNd7Vh  
5p,RI&nlN  
W Tcw4  
private String sSiteURL; //Site's URL ;_XFo&@  
private String sFilePath; //Saved File's Path K,tQ!kk  
private String sFileName; //Saved File's Name PioZIb/{  
private int nSplitter; //Count of Splited Downloading File ]HbY  
av(6wht8  
3RUy,s  
public SiteInfoBean() fQ7V/x!  
{//nSplitter的缺省值为5 eYc$dPE  
//default value of nSplitter is 5 +Z,;,5'5G  
this("","","",5); 2/U.|*mH  
} qRu~$K  
-D<< kra  
i}(LqcYU  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Do9x XK  
{ M.JA.I@XC  
sSiteURL= sURL; `T1  
sFilePath = sPath; }czrj%6  
sFileName = sName; W PC]%:L"  
this.nSplitter = nSpiltter; .zf~.R;>  
gZV
c 5u<  
&L3M]  
} "6A `
 q\  
{aZ0;  
RCJ|P~*  
public String getSSiteURL() IM*y|UHt  
{ g/4
[N{Xf  
return sSiteURL; T%+#xl  
} D2#ZpFp"h  
V(}:=eK  
pG_;$8Hc  
public void setSSiteURL(String value) zxEL+P  
{ 7o\@>rNWP  
sSiteURL = value; y4yhF8E>;U  
} ^"E^zHM(  
UB@Rs|)  

ip\sXVR
 
public String getSFilePath() z>xmRs   
{ rDtY[  
return sFilePath; K&u_R  
} 1pVS&0W  
Z<oaK  
*9 {PEx  
public void setSFilePath(String value) b\f O8{k  
{ DmK57V4L^  
sFilePath = value; Nd4f^Y  
} ]dVGUG8  
4>YR{  
]U?^hZ_  
public String getSFileName() <(#(hDwy  
{ 0J*??g-n  
return sFileName; *YI98  
} yHYsZ,GE  
#Bze
,?@  
I]|Pq  
public void setSFileName(String value) oE@a'*.\  
{ 3l]lwV  
sFileName = value; hXw]K"  
} AhN4mc@  
_1X!EH"  
B
X/8O<s0  
public int getNSplitter() ?JbilK}a  
{ +D6YR$_<  
return nSplitter; ';k5?^T  
} W<{h,j8  
|o"?gB}Dh  
h#I>M`|  
public void setNSplitter(int nCount) $V
;i '(&7  
{ fy1|$d{'  
nSplitter = nCount; Mc lkEfn  
} W_293["lS  
} S)(.,x  
Ng&%o  
- nm"of\o  
/* F~ty!(c  
**Utility.java +bxYGD  
*/ 299H$$WS,Z  
package NetFox; !vi>U|rh  
D_2:k'4  
j8i[ONq^  
public class Utility { >I
afUy  
te`$%NRl  
|T /ZL!  
public Utility() sFKX-S~:  
{ AOZP*\k  
Y;eZ9|Ht9  
[|wZ77\  
} Z{.8^u1I  
NSMyliM1Y  
//线程睡眠 ZmqKQO  
public static void sleep(int nSecond) wVXS%4|v  
{ &<g|gsG`  
try{ Ju
mgb
 
Thread.sleep(nSecond); uh_RGM&  
} *tFHM &a  
catch(Exception e) `cn#B BV  
{ a~`eQ_ND  
e.printStackTrace (); k8yE
di`  
} Eh`7X=Z7E  
} Ufj`euY  
,^r9n[M4M  
//日志 )iX~}7  
public static void log(String sMsg) o#)C^xlQ  
{ \&:nFb%=  
System.err.println(sMsg); 5<k"K^0QS  
} mM~qBrwL  
@n/\L<]t  
iozt&~o  
public static void log(int sMsg) X #dmo/L8  
{ :k]1Lm|
|  
System.err.println(sMsg); h^45,E C  
} [^n.Pns  
} D8Ic?:iX[  
dbLZc$vPj  
OO\+J  
/* YDsb3X<0'  
**TestMethod.java ;V_e>TyG  
*/ GAzU?a{S  
package NetFox; H'5)UX@LP  
u
Cvj!  
"!P3R1;%  
public class TestMethod { ~NgA  
b6M[q_  
tFn)aa~L  
public TestMethod() n80?N}  
{ ///xx/weblogic60b2_win.exe `7Q<'oK  
try{ gaxsv[W>^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +
^ac'Y)A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P:S.~Jq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \w>y`\6mX  
fileFetch.start(); hFUlNJ  
} 5~U/  
catch(Exception e){e.printStackTrace ();} 2W(s(-hD  
I|!OY`ko  
8%mu8l  
} MKCsv+   
P5V}#;v  
\7eUw,~Q>  
public static void main(String[] args) ,t744k')  
{ UgRiIQMq.  
new TestMethod(); 539>WyG5  
} Es`Px_k  
} s)t@ol  
点击下载更多相关资料