http断点续传简单实现（java)

/* W$W7U|Z9y+  
**SiteFileFetch.java fXN;N&I  
*/ btOC\bUMfD  
package NetFox; N^)OlH  
import java.io.*; ZHT.+X:_  
import java.net.*; xAI<<[-  
X!m/I i$q  
ty ~U~  
public class SiteFileFetch extends Thread { ^t"\PpmK<d  
<m!\Ma  
@m6E*2Gg  
SiteInfoBean siteInfoBean = null; //文件信息Bean +.=a R<Q  
long[] nStartPos; //开始位置 kciH  
long[] nEndPos; //结束位置 F n\)*; ^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2neiUNT  
long nFileLength; //文件长度 xGqZ8v`v  
boolean bFirst = true; //是否第一次取文件 Lt)t}0  
boolean bStop = false; //停止标志 vCJjZ%eO%D  
File tmpFile; //文件下载的临时信息 :mij%nQ>$  
DataOutputStream output; //输出到文件的输出流 BkcOsJIz  
nxG vh4'i8  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jGt[[s  
public SiteFileFetch(SiteInfoBean bean) throws IOException p&7>G-.  
{ ,,?t>|3  
siteInfoBean = bean; K
F.?b]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~o+u:]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j=7]"%  
if(tmpFile.exists ()) `'~|DG}a  
{ hod|o1C&  
bFirst = false; #8'%CUF*<8  
read_nPos(); OHB!ec6W  
} oD.f/hi0|  
else Fw|5A"9'a'  
{ iS"rMgq  
nStartPos = new long[bean.getNSplitter()]; B;EdLs}  
nEndPos = new long[bean.getNSplitter()]; ,E_hG3}}  
} ]5^
u^  
F](kU#3"S  
"*UHit;"+{  
1iUy*p65:  
} BQm H9g|2  
T =:^k+  
E|No$QO
)  
public void run() I)6)~[:'  
{ %f@]-  
//获得文件长度 T^"d%au  
//分割文件 b747eR 7E  
//实例FileSplitterFetch lGxG$0`;;  
//启动FileSplitterFetch线程 46*?hA7@r(  
//等待子线程返回 "kMpa]<c-6  
try{ bH&[O`vf  
if(bFirst) IE
3GM
^7\  
{ doG&qXw  
nFileLength = getFileSize(); )yjHABGJ  
if(nFileLength == -1) &AW?!rH  
{ `
jP6;i  
System.err.println("File Length is not known!"); DJ
eG
  
} b.$Gc!g  
else if(nFileLength == -2) &cZ
D{Z  
{ K%S k
{'  
System.err.println("File is not access!"); Zf|f $1-  
} xD1w#FMlQs  
else bY#>   
{ ^NP" m
  
for(int i=0;i<nStartPos.length;i++) ^Xh9:OBF  
{ 
hd\
iW7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \i{=%[c  
} {W@Y4Qqq  
for(int i=0;i<nEndPos.length-1;i++) JTx&_Ok#  
{ 98x(2fCvF(  
nEndPos = nStartPos[i+1]; mgS%YG  
} @n<WM@|l  
nEndPos[nEndPos.length-1] = nFileLength; B;^7Yu0,  
} (d_{+O"  
} _,5(HETE2  
p3X>  
qV5ME#TJ  
//启动子线程 # *\PU  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; dq[CT  
for(int i=0;i<nStartPos.length;i++) N1_nBQF )  
{ ^/
c&Ud  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =8[HC}s|$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0LxA+  
nStartPos,nEndPos,i); ;gf^;%FK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w+PbT6;  
fileSplitterFetch.start(); O0wD"V^W  
} }nuhLt1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \07 s'W U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8eL[,uw  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", V"gnG](2l  
nEndPos = " + nFileLength); &AC-?R|Dp  
// fileSplitterFetch[nPos.length-1].start(); ;[&g`%-H<  
a Z ^SK|E  
WnA]gyc  
//等待子线程结束 `XQM)A  
//int count = 0; 74QWGw`,  
//是否结束while循环 n ,`!yw  
boolean breakWhile = false; iz>a0~(K  
pS9CtQqvgy  
Ju+r@/y%  
while(!bStop) v]c1|?9p'  
{ M++*AZ  
write_nPos(); A-uEZj_RD=  
Utility.sleep(500); r'-)@|  
breakWhile = true; LDO@$jg  
s>^*GQw  
(Zx;GS  
for(int i=0;i<nStartPos.length;i++) ]e 81O#t3  
{ R:zjEhH)  
if(!fileSplitterFetch.bDownOver) 8z\WyDz  
{ cvi+AZ=  
breakWhile = false; _<&IpT{w+  
break; mq>Ag  
} 8&B{bS  
} #NwlKZ-  
if(breakWhile) Sw>AgES  
break; zAS&L%^tV  
Gb\}e}TB[  
^<7)w2ns  
//count++; {6*h';~  
//if(count>4) 's+ Fd~'  
// siteStop(); TAIcp*)ZM  
} W%@6D|^  
5Tkh6s  
=]E;wWC  
System.err.println("文件下载结束！"); j?#S M!f  
} e$fxC-sZ  
catch(Exception e){e.printStackTrace ();} c(i-~_  
} s9zdg"c'  
0O|T\E8e  
e%o6s+"  
//获得文件长度 >DpnIWn  
public long getFileSize() rQ LNo,  
{ pO4}6\1\  
int nFileLength = -1; p~En~?<  
try{ 3T%WfS+  
URL url = new URL(siteInfoBean.getSSiteURL()); aa8WRf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /&Khk #  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8tY],  
rer=o S  
77.5 _  
int responseCode=httpConnection.getResponseCode(); FX4](oM  
if(responseCode>=400) RV.*_FG  
{ 52,pCyU  
processErrorCode(responseCode); wqK>=Ri_  
return -2; //-2 represent access is error [-=PK\ B  
} Rq<T2}K  
eZk [6H  
X2/
`EN\  
String sHeader; ;XRLp:y  
x?VX,9;j  
5JBenTt  
for(int i=1;;i++) (Rve<n6{A  
{ ?yU|;my  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s-J>(|  
//Utility.log(in.readLine()); S2@[F\|r  
sHeader=httpConnection.getHeaderFieldKey(i); :I1
)=8lO  
if(sHeader!=null) FU E/uh  
{ bBb$0HOF  
if(sHeader.equals("Content-Length")) t=d~\_Oa  
{ 80x %wCY`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #db8ur3?  
break; :w_Zr5H]  
} { %vX/Ek  
} ck){N?y  
else -:h5Ky"  
break; 5rr7lwWZ  
} D\jRF-z  
} z AacX@  
catch(IOException e){e.printStackTrace ();} 6Y>MW 4q  
catch(Exception e){e.printStackTrace ();} Kzb&aOw  
-SGR)  
snK$? 9vh  
Utility.log(nFileLength); No=Ig-It  
_>9|"seR  
/QZnN?k  
return nFileLength; ~*GJO74  
} h \hQ  
MMqkNe  
Q.*qU,4);  
//保存下载信息（文件指针位置） G|Yw a=  
private void write_nPos() q.yS j  
{ ;cH|9m:Y  
try{ WZ"NG|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7[rn ,8@  
output.writeInt(nStartPos.length);
N6S0(%  
for(int i=0;i<nStartPos.length;i++) y\$
B9KX  
{ dQVV0)z  
// output.writeLong(nPos);  oJ ~ZzW  
output.writeLong(fileSplitterFetch.nStartPos); R
]VY PNns  
output.writeLong(fileSplitterFetch.nEndPos); f ?_YdVZ  
} 1mm/Ssw:C  
output.close(); CkE@Ll3Z  
} hZ Gr/5f  
catch(IOException e){e.printStackTrace ();} 8xJdK'  
catch(Exception e){e.printStackTrace ();} G(~d1%(  
} ^hv  
LyH8T'C~  
yH#zyO4fD-  
//读取保存的下载信息（文件指针位置） z9}rT<hy  
private void read_nPos() d/!sHr69  
{ R"Nvnpm
 
try{ O&.^67\|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I&l1b>  
int nCount = input.readInt(); []/=!?5B  
nStartPos = new long[nCount]; :0$(umW@I"  
nEndPos = new long[nCount]; i;;CU9`E2q  
for(int i=0;i<nStartPos.length;i++) 8W)3rD>  
{ k!H;(B"s-  
nStartPos = input.readLong(); vmK<_xbwd  
nEndPos = input.readLong(); s\_-` [B0  
} -|B?p
R  
input.close(); 5Al59]  
} !/znovoD  
catch(IOException e){e.printStackTrace ();} JM!rop^  
catch(Exception e){e.printStackTrace ();} M,"4r^%k  
} d|k6#f-E  
BoYWx^VHx^  
Q%KH^<  
private void processErrorCode(int nErrorCode) !SEHDRp  
{ W-<E p<7{  
System.err.println("Error Code : " + nErrorCode); LbOjKM^-  
} Un@B D}@\  
x^^;/%p  
S!A)kK+  
//停止文件下载 z=<x.F  
public void siteStop() `=Pn{JaD  
{ Izm8 qt=m  
bStop = true; y?GRxoCD"e  
for(int i=0;i<nStartPos.length;i++) {LYA?w^GT  
fileSplitterFetch.splitterStop(); pj;cL]L  
p)vyZY[  
EQ1wyKZS2g  
} A<
2_V1  
} `An|a~G1  
//负责部分文件的抓取 !yU!ta Q  
**FileSplitterFetch.java XKN`{h-@  
*/ 7\@[e, ^9  
package NetFox; v/=O:SM}  
_?#}@?  
oRFHq>-.g  
import java.io.*; rD<G_%hP  
import java.net.*; @;2,TY>Di  
= q9>~E{}  
P9; =O$s  
public class FileSplitterFetch extends Thread { EpSVHD:*  
+Rn]6}5m\  
s<Pk[7`*  
String sURL; //File URL SjV;& 1Z/  
long nStartPos; //File Snippet Start Position |_/q0#"  
long nEndPos; //File Snippet End Position wG6>.`:  
int nThreadID; //Thread's ID Z12-Vps  
boolean bDownOver = false; //Downing is over W(a31d  
boolean bStop = false; //Stop identical ^+tAgK2   
FileAccessI fileAccessI = null; //File Access interface U">w3o|  
ce!0Ws+  
fa9c!xDt  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }/q]:3M|  
{ W- 5Z"m1I  
this.sURL = sURL; ce-5XqzY@  
this.nStartPos = nStart; VCfa<hn  
this.nEndPos = nEnd; `wz@l:e  
nThreadID = id; BC0SSR@e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 hw]x T5  
} 9gR@Q%b)  
L;$Gn
"7~  
$}RBK'cr}  
public void run() ,pL%,>R5  
{ E+-ahvk  
while(nStartPos < nEndPos && !bStop) F33&A<(,  
{ _tDSG]  
\nT, NV11  
@)=\q`vV  
try{ F_0vh;Jo  
URL url = new URL(sURL); T
Y}9;QL:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'k[d&sR  
httpConnection.setRequestProperty("User-Agent","NetFox"); +EG?8L,z  
String sProperty = "bytes="+nStartPos+"-"; [)UL}vAO\q  
httpConnection.setRequestProperty("RANGE",sProperty); &U/7D!^X  
Utility.log(sProperty); W(U:D?e  
S_?{<{  
ZP75zeH  
InputStream input = httpConnection.getInputStream();
7`-fN|  
//logResponseHead(httpConnection); l%XuYYQ  
5Y77g[AX2-  
VBV y3fnj  
byte[] b = new byte[1024]; ~5LlIpf36|  
int nRead; 46`(u"RP  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  ;LEO+,6  
{ {]Tb  
nStartPos += fileAccessI.write(b,0,nRead); B^Y AKbY  
//if(nThreadID == 1) 6t@kft>Nv  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A'Q=DoE  
} w5zrEk#  
&,E^y,r  
eT8(O36%  
Utility.log("Thread " + nThreadID + " is over!"); &("HH"!  
bDownOver = true; D >ax<t1K  
//nPos = fileAccessI.write (b,0,nRead); Hw[(v[v  
} 1N8gH&oF
 
catch(Exception e){e.printStackTrace ();} TY,5]*86I&  
} }i,LP1R  
} o"h*@.  
aVTTpMY  
Z,~Bz@5`"  
//打印回应的头信息 J*HZ=6L  
public void logResponseHead(HttpURLConnection con) XL!\Lx  
{ $&IF#uDf  
for(int i=1;;i++) sXe=4`O  
{ @~WSWlQW  
String header=con.getHeaderFieldKey(i); rBNl%+ sB  
if(header!=null) )Pr*\<Cld  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 66RqjP '2  
Utility.log(header+" : "+con.getHeaderField(header)); ,]CZ(q9-  
else PeCU V6  
break;
x-W6W  
} k)l*L1Y4:  
} $:&?
!>H  
U9N1)3/u  
`2}H
$D  
public void splitterStop() E<=h6Ha  
{ $~ 6Y\O  
bStop = true; /eFudMl  
} -TL `nGF  
wD9Gl.uQ  
T
F0DQP  
} H~fX>6>  
s+mNr3  
y~ubH{O#  
/* J})#43P  
**FileAccess.java b \pjjb[  
*//文件访问(定位，写) ;;6e t/8  
package NetFox; (<.uvq61  
import java.io.*; P1\:hh  
8Xo`S<8VS  
xRTr<j0s  
public class FileAccessI implements Serializable{ [X9s\H  
j?eWh#[K"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 zxo0:dyw7  
RandomAccessFile oSavedFile; A'jw;{8NpF  
long nPos; l8O
12   
hSBR9g  
49/j9#hr  
public FileAccessI() throws IOException /3]b!lFZZ  
{ jGp|:!'w  
this("",0); .JkcCEe{G  
} C}})dL;(  
NTj:+z0  
,7wxVR%Ys  
public FileAccessI(String sName,long nPos) throws IOException KN41kkN  
{ HizMjJ|  
oSavedFile = new RandomAccessFile(sName,"rw"); Muhq,>!U  
this.nPos = nPos; tA,#!Z0  
oSavedFile.seek(nPos); OfSy_#aEK  
} x37pj)i/  
wF@mHv  
.bwKG`F  
public synchronized int write(byte[] b,int nStart,int nLen) Hh|a(Zq,  
{ O&ur|&v  
int n = -1; ue YBD]3'  
try{ w_*UFLMSqR  
oSavedFile.write(b,nStart,nLen); !;[cm|<E  
n = nLen; QH?}uX'x)G  
} muD7+rn?&  
catch(IOException e) pON
BF3H8  
{ g%Yw Dr=0t  
e.printStackTrace (); !'yl
h8}  
} Ru1I,QvCj"  
U}r^M( s!  
g{]C@,W  
return n; k1EAmA l  
} Wa/&H$d\u@  
l7g< $3
 
81(.{Y839_  
} =Wb!j18]  
d|nJp-%V  
?O]iX;2vM  
/* _t9@ vVQ  
**SiteInfoBean.java {95z\UE}  
*/ hH=H/L_Z  
package NetFox; y093-  
- %ul9}.  
2N,<~L`FX'  
public class SiteInfoBean { n'dxa<F2|  
Pk94O  
AqD)2O{VO  
private String sSiteURL; //Site's URL 8Z^9r/%*Z  
private String sFilePath; //Saved File's Path d#?.G3YmK  
private String sFileName; //Saved File's Name 
'h?;i2[  
private int nSplitter; //Count of Splited Downloading File p=tj>{  
W~TT`%[  
2J^jSgr50d  
public SiteInfoBean() ;M<jQntqS{  
{//nSplitter的缺省值为5 m' LRP:9v  
//default value of nSplitter is 5 @kq~q;F  
this("","","",5); ~ jR:oN  
} ` 0YI?$G1  
FG?69b>  
RV*7?y%3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) JZCRu_M>|  
{ ~y#jq,i/  
sSiteURL= sURL; /& qN yo  
sFilePath = sPath; f*+eu@  
sFileName = sName; h{dR)#)GF<  
this.nSplitter = nSpiltter; hQm"K~SW
=  
D"5uN0Z  
?1r>t"e5  
} q~3dbj  
O<@S,/Q4  
U[!x 0M  
public String getSSiteURL() $@[`/Uh   
{ Jgf73IX[  
return sSiteURL; #$<7
 
} yK1Z&7>J>  
]5!}S-uJq  
fgb%SIi?  
public void setSSiteURL(String value) ~"<AYJlO  
{ pH?tr  
sSiteURL = value; MZpG1  
} ERql^Yr  
qqm7p ,j  
mOLP77(o  
public String getSFilePath() Cst:5m0!  
{ S 1%/ee3  
return sFilePath; pa7Iz^i  
} ) o)k~6uT  
_x.!, g{  
\2F$FRWo  
public void setSFilePath(String value) t)yWQV  
{ 1>JUI5 {  
sFilePath = value; d+5KHfkK  
} !y8/El  
l?+67cQLA  
XJ3 5Z+M  
public String getSFileName() _L?`C  
{ kWv)+  
return sFileName; yq3i=RB(  
} [
V\0P,l  
ls(lL\  
~*Fbs! ;,  
public void setSFileName(String value) CS:"F) at  
{ |@J:A!  
sFileName = value; CM; r\,o  
} Us4ijR d  
vgfLI}|5  
=:T pH>f*  
public int getNSplitter() "?I]h  
{ (GLd"
Zq  
return nSplitter; J/M_cO*U  
} {x3"/sF  
V!eq)L  
@`qhQ  
public void setNSplitter(int nCount) *x^W`i   
{ HG(J+ocn   
nSplitter = nCount; 7XE |5G  
} AE:IXP|c  
} g~5$X{  
93zoJiLRf  
=WaZy>n}7  
/* hpftVEB  
**Utility.java N:#"4e  
*/ u$7od$&S  
package NetFox; =.
@{uu;  
Ppw0vaJ^  
b%w?YR  
public class Utility { [B}$U|V0  
1^G*)Qn5Df  
xWY%-CWY.  
public Utility() 95.m^~5  
{ jU1([(?"  
D^(Nijl9U  
W'Wr8~{h  
} 5*.JXxE;U  
JLS|G?#0  
//线程睡眠 gr\UI!]F  
public static void sleep(int nSecond) .OLm{  
{ kaSy 9Y{  
try{ &E0d{2  
Thread.sleep(nSecond); PZVh)6f"c  
} w1Z9@*C!  
catch(Exception e) $wL zaZL|  
{ >t-9yO1XQq  
e.printStackTrace (); {> T r22S  
} }O_kbPNw  
} K{eq'F5M  
7Eo
a~  
//日志 +,`Cv_O  
public static void log(String sMsg) Lh0qB)>  
{ X.u&4SH  
System.err.println(sMsg); `XAlzI  
} B}Q.Is5  
@dl{.
,J  
+R
XKI{0Km  
public static void log(int sMsg) uJQ#l\t  
{ LvlVZjT  
System.err.println(sMsg); |@{4zoP_N  
} =Q#} ,T  
} xgw[)!g^\  
{+CW_ce  
!(:R=J_h  
/* W@R\m=e2  
**TestMethod.java .h!oo;@  
*/ jV83%%e  
package NetFox; 9ihB;m'C)  
H_*;7/&  
q*`1
<9{H  
public class TestMethod { 7(RtPLpZ  
`Sh#> Jp  
ElJM. a  
public TestMethod() ~p9nAACU  
{ ///xx/weblogic60b2_win.exe Up:<NHJT  
try{ 2Zf}t  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); G}!dm0s$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #G'Y2l  
SiteFileFetch fileFetch = new SiteFileFetch(bean); qmNgEz%  
fileFetch.start(); ,(h:0L2v7d  
} 8ZYF%  
catch(Exception e){e.printStackTrace ();} jNKu5"HB  
C%hMh/Li;  
AfU~k!4`  
} WCK;r{p%I  
;?-A4!V,
 
QWqEe|}6  
public static void main(String[] args) CCZ'(Tkq  
{ ulY8$jB  
new TestMethod(); V1[Cc?o  
} u\LbPk  
} *G'R+_tdE  
点击下载更多相关资料