http断点续传简单实现（java)

/* G/x3wR  
**SiteFileFetch.java c28oLT1|D  
*/ ^U0apI  
package NetFox; <wIp$F.  
import java.io.*; 9`LU=Xv/  
import java.net.*; 5O;/ lX!u  
OlD7-c2L]  
+~R.7NE%  
public class SiteFileFetch extends Thread { "uV0Oj9:  
')5jllxv  
"wc`fg"3  
SiteInfoBean siteInfoBean = null; //文件信息Bean K1m!S9d`x  
long[] nStartPos; //开始位置 ,Ut!u)  
long[] nEndPos; //结束位置 #C;#$|d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :ofE8]  
long nFileLength; //文件长度 y1@"H/nYJ  
boolean bFirst = true; //是否第一次取文件 +1JZB*W  
boolean bStop = false; //停止标志 Apw-7*/  
File tmpFile; //文件下载的临时信息 F1Zk9%L%9$  
DataOutputStream output; //输出到文件的输出流 0C9QAJa  
i9#`F.7F  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） dpc=yXg>"c  
public SiteFileFetch(SiteInfoBean bean) throws IOException Gaw,1Ow!`2  
{ ; @[.$Q@I  
siteInfoBean = bean; K'{wncumQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .@x"JI>;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Y(Z(dV!Po  
if(tmpFile.exists ()) rRA_'t;uK  
{ !0d9<SVC  
bFirst = false; +v`^_  
read_nPos(); z
m_hLk  
} ?(`nBlWQ5  
else IdC k  
{ H)?" 8 s  
nStartPos = new long[bean.getNSplitter()]; 4`^TC[
  
nEndPos = new long[bean.getNSplitter()]; FZ}C;yUPD  
} lHj7O&+  
%_i0go,^  
*}Ae9  
c_DB^M!h  
} `6l24_eKf  
*{4{<O<4  
01SFOPuR%(  
public void run() \:f}X
?:  
{ A%sxMA!K,  
//获得文件长度 '!|E+P-  
//分割文件 ogh2kh
t  
//实例FileSplitterFetch BYA=M*f  
//启动FileSplitterFetch线程 b}q(YgH<  
//等待子线程返回 E%v[7 ST  
try{ ">4[+'  
if(bFirst) 0UAr}H.:  
{ =4%WOI  
nFileLength = getFileSize(); qz_TcU'  
if(nFileLength == -1) "~,(
Xa3x  
{ B )3SiU  
System.err.println("File Length is not known!"); daokiU+l2  
} TJGKQyG$L  
else if(nFileLength == -2) 14)kKWG  
{ m`4j|5  
System.err.println("File is not access!"); HpgN$$\@  
} P^{`d_[K%  
else =_~'G^`tu  
{ EPUJa~4  
for(int i=0;i<nStartPos.length;i++) '5+, lRu  
{ Jut'xA2Dr  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,C12SM*@  
} #| e5  
for(int i=0;i<nEndPos.length-1;i++) 9?mOLDu}Q0  
{ Q,LWZw~"  
nEndPos = nStartPos[i+1]; l9Cy30O6  
} w})&[d  
nEndPos[nEndPos.length-1] = nFileLength;
sC*E;7gT,  
} dIh(~KqB  
} V:$1o  
kO\&mL& qD  
%Z
i,nHg8  
//启动子线程 r?{LQWP>e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Mh@ylp+q  
for(int i=0;i<nStartPos.length;i++) 0|3B8
m  
{ %4g4 C#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }t{^*(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), peP:5WB  
nStartPos,nEndPos,i); UgBY ){<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?Pf ,5=*B  
fileSplitterFetch.start(); m`w6wz  
} oFA$X Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iO#xIl<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); cN(QTbyl6Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d=Ihl30m  
nEndPos = " + nFileLength); < 2r#vmM  
// fileSplitterFetch[nPos.length-1].start(); x-P_}}K 79  
Vf2!0  
U%6lYna{M#  
//等待子线程结束 Wa<NId  
//int count = 0; s`#j8>`M  
//是否结束while循环 |6G5 ?|  
boolean breakWhile = false; m<;" 1<k  
wH5O>4LO  
J~ rC  
while(!bStop) ?9M+fi  
{ Hq
y>!1!  
write_nPos(); Nr7.BDA  
Utility.sleep(500); HCZ%DBU96  
breakWhile = true; NWX%0PGZ  
tg4&j$  
&l)v'  
for(int i=0;i<nStartPos.length;i++) /60=N`i  
{ v\T1,Z@N^  
if(!fileSplitterFetch.bDownOver)  o=
5uM  
{ z?g4^0e  
breakWhile = false; PhL5EYn  
break; / S^m!{  
} KV(W|~+rM  
} ))zaL2UP.  
if(breakWhile) Z@Z`8M@Q,  
break; 0|k[Wha#  
u01^ABn  
f)fw87UPc  
//count++; y9mZQq  
//if(count>4) \M^4DdAy  
// siteStop(); e/%YruzS  
} ^W*)3;5  
TW? MS em  
gpl!Iz~5  
System.err.println("文件下载结束！"); 6XqO'G  
} y$W3\`2q  
catch(Exception e){e.printStackTrace ();} uvd>  
} H*<dte<  
mjc:0hH  
Hc3/`.nt  
//获得文件长度 }e|]G,NZO  
public long getFileSize() %^A++Z$`  
{ nr6U> KR^  
int nFileLength = -1; $^GnY7$!>  
try{ &WS%sE{p_  
URL url = new URL(siteInfoBean.getSSiteURL()); D]y.!D{l2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A>S2BL#=  
httpConnection.setRequestProperty("User-Agent","NetFox"); l;i u`  
cE?
J]5#^  
(b5af_ c  
int responseCode=httpConnection.getResponseCode(); VNfx>&`  
if(responseCode>=400) pm|]GkM  
{

BGOI  
processErrorCode(responseCode); /zAx`H  
return -2; //-2 represent access is error )`0 j\  
} J]e&z5c  
B 8,{jwB  
A
2 )%+  
String sHeader; ^hJ,1{o  
gE#,QOy  
UNHHzTsr?  
for(int i=1;;i++) s"Wdbw(O'  
{ ;anG F0x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cgAcAcmY  
//Utility.log(in.readLine()); $Vh82Id^  
sHeader=httpConnection.getHeaderFieldKey(i); w0SgF/"@  
if(sHeader!=null) pDT6>2t  
{ Mf"B!WU>]B  
if(sHeader.equals("Content-Length")) 9 R1]2U$|  
{ ~b/>TKn+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I_Qnq4Sk(  
break; ml2HA4X&$Y  
} ~heF0C_  
} 9yPB)&"EF  
else {I ,
'  
break; I._=q  
} X"sN~Q.0  
} f]ef 1#  
catch(IOException e){e.printStackTrace ();} !ywc).]e  
catch(Exception e){e.printStackTrace ();} z m%\L/BF  
82<
!b]^1  
D.~t#a A  
Utility.log(nFileLength); ' wEP:}  
~Q0}>m,S  
&}ow-u9c3  
return nFileLength; f~Su F,o@h  
} 4$rO,W/&0  
<|@9]>z  
m,b<b91  
//保存下载信息（文件指针位置） 9UZX+@[F  
private void write_nPos() 0NGokaD)H  
{ x0]*'^aA  
try{ w,&RHQB  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >8##~ZuF+
 
output.writeInt(nStartPos.length); ,yoT3_%P  
for(int i=0;i<nStartPos.length;i++) jB;+tDC!Co  
{ Hs9uDGWp  
// output.writeLong(nPos); Z,z^[Jz  
output.writeLong(fileSplitterFetch.nStartPos); U"Y$7
~  
output.writeLong(fileSplitterFetch.nEndPos); /i<g>*82  
} Kt-@a%O0  
output.close(); Ok@5`?08  
} )-mB^7uXGv  
catch(IOException e){e.printStackTrace ();} _Cxs"to  
catch(Exception e){e.printStackTrace ();} Gs%kqD{=  
} bFpwq#PDW>  
L\UYt\ks  
B?]^}r  
//读取保存的下载信息（文件指针位置） U*Q$:%72vO  
private void read_nPos() c09uCito  
{ C-Mop,w  
try{ ]T
$~a8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SF6n06UZu  
int nCount = input.readInt(); mVxS[Gq  
nStartPos = new long[nCount]; m4EkL  
nEndPos = new long[nCount]; 0wx`y$~R  
for(int i=0;i<nStartPos.length;i++) ;3w W)gL1  
{ <
X: 9y  
nStartPos = input.readLong(); ykZ)`E]P`  
nEndPos = input.readLong(); $V[ob   
} TPrwC~\B/  
input.close(); 8?PNyO-Wt5  
} `0L!F"W  
catch(IOException e){e.printStackTrace ();} bNXT*HOZb3  
catch(Exception e){e.printStackTrace ();} EprgLZ1B  
} 4`i_ 4&TS  
WPPmh~:  
rA9"CN  
private void processErrorCode(int nErrorCode) L"IdD5`7T  
{ =KX:&GU  
System.err.println("Error Code : " + nErrorCode); ?g!)[p`v
 
} "2 Kh2[K  
@Fo0uy\G  
8 }-"&-X  
//停止文件下载 )#1@@\< ^T  
public void siteStop() P?>p+dM  
{ YYhRdU/g  
bStop = true; lO:[^l?F  
for(int i=0;i<nStartPos.length;i++) :B
l $c,J  
fileSplitterFetch.splitterStop(); nH;^$b'LZ  
!
dZC-U~  
Up8#Nz T  
} ~}uTC36C\  
} )jnxR${M  
//负责部分文件的抓取 u{HB5QqK  
**FileSplitterFetch.java NJ3b Oq  
*/ CT/`Kg_  
package NetFox; qPWYY  
6%:N^B=%}  
~/QzL.S;p  
import java.io.*; 0n
BAO  
import java.net.*; OD{Rh(Id  
-
V(5U!^B  
[}.OlR3)  
public class FileSplitterFetch extends Thread { B+,Z 3*  
V0"UFy?i  
\!`*F:7]-  
String sURL; //File URL LvB-%@n  
long nStartPos; //File Snippet Start Position ;l"z4>k
t7  
long nEndPos; //File Snippet End Position k}~|jLu@g  
int nThreadID; //Thread's ID p^NYJV  
boolean bDownOver = false; //Downing is over >!?u8^C  
boolean bStop = false; //Stop identical D[ny%9 :  
FileAccessI fileAccessI = null; //File Access interface ;4%^4<+3  
K@6$|.bc  
BoXQBcG]w  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @32JMS<  
{ )~s(7 4`}  
this.sURL = sURL; ]hc.cj`\W&  
this.nStartPos = nStart; 0fwo8NgX  
this.nEndPos = nEnd; Z#%4QIz?  
nThreadID = id; u+kXJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ohOze\T)=  
} Sm{idky)[  
|s+y]3-_  
5e6f)[}  
public void run() {a\m0Bw/  
{ 9ssTG4Sa  
while(nStartPos < nEndPos && !bStop) D`V03}\-  
{ ^g"G1,[%w  
?l &S:` L  
.IE2d%]?  
try{ iG!t
RNQ{y  
URL url = new URL(sURL); ] K3^0S/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g/)mbL>=  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1.6yi];6  
String sProperty = "bytes="+nStartPos+"-"; _Y?p =;  
httpConnection.setRequestProperty("RANGE",sProperty); (Z fY/  
Utility.log(sProperty); f![?og)I%  
1kEXTs=,  
9LI#&\lba  
InputStream input = httpConnection.getInputStream(); N7v7b<6  
//logResponseHead(httpConnection); d,tGW  
j'R{llZW  
_Ryt|# y  
byte[] b = new byte[1024]; 2~h! ouleY  
int nRead; .76T<j_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) c6.S jV  
{  >\6T
m  
nStartPos += fileAccessI.write(b,0,nRead); .fY1?$*6c  
//if(nThreadID == 1) ,@!io  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <&^
P1x<x  
} 094~  s  
+GqK$B(x7  
-}#=L@  
Utility.log("Thread " + nThreadID + " is over!"); k<(G)7'gm  
bDownOver = true; K9O%SfshF  
//nPos = fileAccessI.write (b,0,nRead); BPs|qb-  
} ;n]GHqzY_  
catch(Exception e){e.printStackTrace ();} *'[8FZ|dQ  
} 6Y9FU  
} v8 rK\  
}%2hBl/
  
{x_SnZz&  
//打印回应的头信息 eYNu78u   
public void logResponseHead(HttpURLConnection con) l Oxz&m  
{ T6mbGE*IeE  
for(int i=1;;i++) pV:;!+  
{ Ad7N'1O  
String header=con.getHeaderFieldKey(i); W;L<zFFbU)  
if(header!=null) .Z?@;2<l  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d ?Uj3G  
Utility.log(header+" : "+con.getHeaderField(header)); ["O/%6b9+  
else GO&~)Vh&7  
break; D/U=zDpiB  
} l/*NscYtQ  
} &k53*Wo  
9d kuvk}:  
>%6a$r~@  
public void splitterStop() M9~eDw'Pr  
{ py|ORVN(Z  
bStop = true; +|0f7RB+R  
} KYw~(+gHv2  
I'h|7y\  
4C:-1gu7  
} Q' b@5o  
&JUHm_wd&S  
-ElK=q  
/* ;D8175px;  
**FileAccess.java xxy (#j$  
*//文件访问(定位，写) #!.26RM:P  
package NetFox; C\`*_t  
import java.io.*; "5wer5? t  
dgEH]9j&  
6[x6:{^J  
public class FileAccessI implements Serializable{ [LF<aR5  
|7#S0Ca@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <Jc :a?ICe  
RandomAccessFile oSavedFile; 2/dvCt6 N  
long nPos; w|,BTM:e  
uD=FTx  
pLiGky  
public FileAccessI() throws IOException F[@M?  
{ zk++#rB  
this("",0); /_(q7:<ZF  
} dy' J~Eo7  
L,\wB7t  
<*Bk.>f!  
public FileAccessI(String sName,long nPos) throws IOException ']&rPvkL  
{ K@<%Vc>L(  
oSavedFile = new RandomAccessFile(sName,"rw"); Z#vU~1W  
this.nPos = nPos; Ze.\<^-t  
oSavedFile.seek(nPos); o4t6NDa  
} qdNt2SO  
c'}dsq\  
*Dhy a g  
public synchronized int write(byte[] b,int nStart,int nLen) h0z>dLA#2  
{ 5Tg[-tl  
int n = -1; Q!ReA{  
try{ Dt~ |)L+  
oSavedFile.write(b,nStart,nLen); ""W*) rR   
n = nLen; N<e72x  
} [bh8Nj\E  
catch(IOException e) aovw'
O\Q  
{ 0`Hr(J`

F  
e.printStackTrace (); mmvo >F"  
} !mIr_d2"  
J/xbMMb   
MO%kUq|pg  
return n; :~wU/dEEiz  
} _Squ%z:D  
5H79-QLd  
_j sJS<21  
} xcM*D3  
]t)#,'$^[W  
7GDrH/yK  
/* [4 y7tjar^  
**SiteInfoBean.java |PxTm  
*/ 4apaUP=Jp  
package NetFox; y*<x@i+h  
s9[547?`  
&xLCq&j
1  
public class SiteInfoBean { k0@*Up3{7  
SUN!8 qFA  
'Da*MGu9  
private String sSiteURL; //Site's URL EWC
{896,  
private String sFilePath; //Saved File's Path @;t6Slc"~  
private String sFileName; //Saved File's Name RAU"  
private int nSplitter; //Count of Splited Downloading File 0BrAgv"3a_  
{,+MaH  
AMre(lgh  
public SiteInfoBean() kHbH{])  
{//nSplitter的缺省值为5 @(W{_mw  
//default value of nSplitter is 5 %EEQ^lm  
this("","","",5); 5j~1%~,
#  
} m
<'&`B;  
n5+Z|<3)  
_lMSW6  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1n!xsesSc  
{ sd&^lpH  
sSiteURL= sURL; *ry}T=  
sFilePath = sPath; N~|Z@pU"  
sFileName = sName; de_%#k1:L  
this.nSplitter = nSpiltter; `6xr:s  
G\(cnqHk  
Yfr4<;%  
} g[Q+DT  
A/!"+Yfw  
Ctx`b[&KXX  
public String getSSiteURL() xG WA5[YV  
{ N?2C*|%f  
return sSiteURL; 7S2"e[-x  
} s("\]K  
3IG<Ot9  
LYO2L1u)  
public void setSSiteURL(String value) <DZ$"t  
{ K05U>151  
sSiteURL = value; SS6K7  
} [H@71+_Q  
U:0Ma6<  
HCw,bRxm  
public String getSFilePath() N/78Ub  
{ K%ptRj$  
return sFilePath; CE@[Z  
} ?$#P =VK  
^
^B~v<uK  
H[RX~Xk2E  
public void setSFilePath(String value) 4L_)@n}  
{
>hY.F/[  
sFilePath = value; qTSe_Re  
} Eh*(N(`  
3EHB~rL/C  
c~+KrW
bZ~  
public String getSFileName() JwQ/A[b  
{ erhez  
return sFileName; sC A  
} @b!W8c6  
waU2C2!w
 
hHZ'*,9 y  
public void setSFileName(String value) }T-'""*  
{ 1obajN  
sFileName = value; '<s54 Cb  
} wXtp(YwlH  
Y?$  
h5(OjlMC  
public int getNSplitter() fejC,H4I  
{ pp{2[>  
return nSplitter; {A'
*3(8  
} PW82 Vp.  
OJd/#KFm  
}m'n1tm;  
public void setNSplitter(int nCount) x[0O*ty-*<  
{ w {"1V7|  
nSplitter = nCount; Cv}^]_`Q  
} T2 S fBs  
} i4]oE&
G  
On54!
m  
C}(@cn `L  
/* y/5GY,z%aL  
**Utility.java VZq~ -$  
*/ #wo *2(  
package NetFox; Inn{mmz 1  
`<7!Rh,tS^  
|-)8=QDz)r  
public class Utility { AL.psw-Il  
o+B)  
=#v? }JG  
public Utility() s*s~yH6  
{ L
SP p  
_CfJKp)  

FJ-H ;  
} JhfVm*,  
 ?C#E_  
//线程睡眠 o8Gygi5  
public static void sleep(int nSecond) fGO\f;P  
{ tAF?.\x"g  
try{ Z&Ciy n  
Thread.sleep(nSecond); I#&r5Q  
} :nQlS  
catch(Exception e) P RWb6  
{ LP=j/qf|  
e.printStackTrace (); ATl?./Tu  
} Xv|=RNz  
} }!AS?  
n{FjFlX2=  
//日志 )@X0'X<  
public static void log(String sMsg) }Nsdk',}  
{ ^J5{quV
 
System.err.println(sMsg); iN[x *A|h  
} L23}{P  
d<6F'F^w.7  
D]]wJQU2  
public static void log(int sMsg) 1|(Q|  
{ BG+ityH  
System.err.println(sMsg); H*'1bLzq  
} }=5>h' <  
} p
 1'l D  
b,E?{uG  
?: yz/9(  
/*  ch8a  
**TestMethod.java eF,F<IJT{  
*/ N)H "'#-  
package NetFox; Q$c6l[(g  
-2M~KlYl  
x,!Dd  
public class TestMethod { d
+ jX49Vt  
lh8QtPe  
"`$,qvNN  
public TestMethod() V4n~Z+k  
{ ///xx/weblogic60b2_win.exe JaCX}[R  
try{ q 84*5-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x b"z%.
j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); m2c'r3UEu  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P:"R;YCvE  
fileFetch.start(); >>y`ap2%V  
} 6ZqU:^3  
catch(Exception e){e.printStackTrace ();} 0%ul6LvM  
\Ii{sn9  
X
p:A;i9  
} "mK`3</G  
Alxf;[s  
 ]n!V  
public static void main(String[] args) r5}p .  
{ wa"0`a:`;  
new TestMethod(); Vu:ZG*^  
} P`biHs8O  
} 'J,UKK\5  
点击下载更多相关资料