http断点续传简单实现（java)

/* IdY\_@$ v  
**SiteFileFetch.java ]g}Tqf/N%  
*/ A4kYEA  
package NetFox; &DUt`Dr w  
import java.io.*; 0/r\#"+XT  
import java.net.*; G/cE2nD  
,7wxVR%Ys  
J~\`8cds  
public class SiteFileFetch extends Thread { fi/[(RBG  
c= f_  
SfHs,y6
 
SiteInfoBean siteInfoBean = null; //文件信息Bean M@R_t(&=  
long[] nStartPos; //开始位置 }Y{aVn&C  
long[] nEndPos; //结束位置 Py}`k1t*f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 lDBn3U&z>  
long nFileLength; //文件长度 .1O  
boolean bFirst = true; //是否第一次取文件 |G!PG6%1  
boolean bStop = false; //停止标志 ^+v6?%m  
File tmpFile; //文件下载的临时信息 p-KMELB  
DataOutputStream output; //输出到文件的输出流 AdCi*="m  
p_K``JE  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） l}#z#L2,`  
public SiteFileFetch(SiteInfoBean bean) throws IOException pON
BF3H8  
{ dcK7Dd->  
siteInfoBean = bean; !'yl
h8}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ru1I,QvCj"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U}r^M( s!  
if(tmpFile.exists ()) g{]C@,W  
{ nWrknm  
bFirst = false; \|OW`7Q)k  
read_nPos(); y)5U*\b  
} &n5Lc`  
else {nl]F  
{ X={n9*Sd8  
nStartPos = new long[bean.getNSplitter()]; c5jd q[0  
nEndPos = new long[bean.getNSplitter()]; d|nJp-%V  
} ?O]iX;2vM  
>x$eKN  
Sk'S`vH  
)v4?+$g  
} gEejLyOag  
=z=$S]qN  
Hl@)j   
public void run() f/_RtOSw  
{ Z(' iZ'55F  
//获得文件长度 ]i}3
`e?  
//分割文件 3jH8pO^  
//实例FileSplitterFetch E0g` xf6c  
//启动FileSplitterFetch线程 AbWnDqv  
//等待子线程返回 jK#[r[q{  
try{ ;bC163[  
if(bFirst) 'CTvKW  
{ 2g)W-M  
nFileLength = getFileSize(); s@WF[S7D  
if(nFileLength == -1) f1Ak0s,zrc  
{ I 0/enL  
System.err.println("File Length is not known!"); T'n~QfU  
} qac4GZ  
else if(nFileLength == -2) FG?69b>  
{ (x.O]8GKP  
System.err.println("File is not access!"); (A6-9g>  
} e``X6=rcG  
else 4h|48</  
{ h{&X`$  
for(int i=0;i<nStartPos.length;i++) "`sr#  
{ %:^|Q;xe  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >bKN$,Qen  
} b~M3j&  
for(int i=0;i<nEndPos.length-1;i++) b r"47
i  
{ !,f#oCL  
nEndPos = nStartPos[i+1]; %E!^SF?Y  
} tkN5|95  
nEndPos[nEndPos.length-1] = nFileLength; {}vB#!  
} F
?+K~['i  
} w(sD}YA)  
L5E|1T  
Nb))_+/  
//启动子线程 LI>tN R~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; MZpG1  
for(int i=0;i<nStartPos.length;i++) ERql^Yr  
{ qqm7p ,j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mOLP77(o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +m> %(?=A  
nStartPos,nEndPos,i); t+R8{9L-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -Qs4s  
fileSplitterFetch.start(); RJ#xq#l  
} ;8Z\bHQ>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N8<Wm>GLX~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +/g/+B
_b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E1atXx  
nEndPos = " + nFileLength); p4\r`  
// fileSplitterFetch[nPos.length-1].start(); Z#-:zD7_  
Qx9lcO_  
a0vg%Z@!  
//等待子线程结束 t@a2@dX|  
//int count = 0; Vb=Oz  
//是否结束while循环 YS}uJ&WoF  
boolean breakWhile = false; QzjLKjl7p4  

JN{.-k4Ha  
g$++\%k&  
while(!bStop) NH?q/4=I0W  
{ ?a8 o.&`l  
write_nPos(); Kr$ w"]  
Utility.sleep(500); a88(,:t  
breakWhile = true; ~w<u!  
{Jv m *  
:R/szE*Ak  
for(int i=0;i<nStartPos.length;i++) `|p3@e  
{ wnf'-dw]  
if(!fileSplitterFetch.bDownOver) B&l5yI b  
{ [LwmzmV+F  
breakWhile = false; vJX3fE}F  
break; 9-<EeV_/  
} ] ~;x$Z)  
} `@8QQB  
if(breakWhile) e 1W9Z $m  
break; F_m[EB  
])dq4\Bw  
&E@8 z&  
//count++; ]fN\LY6p  
//if(count>4) 5jj
<sj!S  
// siteStop(); d

tK[H+  
} ,W"[q~  
(T1)7%Xs  
'\I.P  
System.err.println("文件下载结束！"); ,a N8`M  
} ;&|MNN^  
catch(Exception e){e.printStackTrace ();} _Y7uM6HL\  
} kPN:m ow  
Y
lI/~J  
YT)jBS~&  
//获得文件长度 O|t@p=]  
public long getFileSize() j@jaFsX|  
{ nf,R+oX  
int nFileLength = -1; CzP?J36W^  
try{ icq!^5BzL  
URL url = new URL(siteInfoBean.getSSiteURL()); nLn3kMl4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b' 1%g}  
httpConnection.setRequestProperty("User-Agent","NetFox"); oy I8}s:  
Tw:j}ERq  
&|;XLRHP}  
int responseCode=httpConnection.getResponseCode(); 3h:"-{MW.  
if(responseCode>=400) OK{_WTCe>  
{ \,YF['Qq  
processErrorCode(responseCode); Ga5O&`h  
return -2; //-2 represent access is error =(ULfz[:  
} MfJ;":]O!  
&5]&6TD6  
0n5{Wr$  
String sHeader; jB+K)NXHL  
@dl{.
,J  
+R
XKI{0Km  
for(int i=1;;i++) uJQ#l\t  
{ s-V5\Lip,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); u:~2:3B  
//Utility.log(in.readLine()); >w,o|  
sHeader=httpConnection.getHeaderFieldKey(i); idWYpU>gC  
if(sHeader!=null) ZT*RD2,  
{ +Y7"!wYR>  
if(sHeader.equals("Content-Length")) /U |@sw4  
{ (*{Y#XD{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {)E)&lL  
break; ao2NwH##  
} ~>h_#sIBC  
} "E4;M/  
else !j'9>G{T  
break; >
/,7j:X  
} C&Nga `J  
} |"4+~z%/9!  
catch(IOException e){e.printStackTrace ();}
R>BZQugZ~  
catch(Exception e){e.printStackTrace ();} QU4/hS;Ux  
cg16|  
 T06BrX  
Utility.log(nFileLength); 3q{op9_T7  
8ZYF%  
KI* erK [d  
return nFileLength; y|sU-O2}Dl  
} ELh`|X  
b
`?$;5  
oMM+af  
//保存下载信息（文件指针位置） ZCdlTdY   
private void write_nPos() <g/Z(<{wor  
{ y~,mIM$[@  
try{ >LvQ&fAo  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (o+(YV^  
output.writeInt(nStartPos.length); 6Vr:?TI7  
for(int i=0;i<nStartPos.length;i++) |?zFm mh  
{ N~c Y~a  
// output.writeLong(nPos); 2~yYwX  
output.writeLong(fileSplitterFetch.nStartPos); R#D>m8&}3  
output.writeLong(fileSplitterFetch.nEndPos); CC?L~/gPN  
} )Sz2D[@n  
output.close(); ${(c`X  
} k!9LJ%Xh  
catch(IOException e){e.printStackTrace ();} }n!$)W*?  
catch(Exception e){e.printStackTrace ();} "pQFIV,  
} ;5i~McH# t  
+48a..4sN  
qnFi./  
//读取保存的下载信息（文件指针位置） 7x6q:4Ep\  
private void read_nPos() $~$NQe!/  
{ ]
/G~ L  
try{ 8GGC)2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0A]+9@W;  
int nCount = input.readInt(); =6PTT$,
 
nStartPos = new long[nCount]; >!o||Yn  
nEndPos = new long[nCount]; CN7 2 E  
for(int i=0;i<nStartPos.length;i++) KwEyMR!  
{ hFLD2<   
nStartPos = input.readLong(); 7iI6._"!w  
nEndPos = input.readLong(); jv8diQ.  
} <xb=.xe  
input.close(); Bo)N<S_=^  
} %E1_)^^  
catch(IOException e){e.printStackTrace ();} \FE  
catch(Exception e){e.printStackTrace ();} }f/xMp-Y  
} FLWQY,  
w.AF7.X`1  
w6b
\l1Z  
private void processErrorCode(int nErrorCode) rsr}%J  
{ ?^y!}(  
System.err.println("Error Code : " + nErrorCode); |j?iD  
} u 2)#Ml  
uA`EJ )d  
rMV<}C ^  
//停止文件下载 3Ryae/Nk  
public void siteStop() #2dd`F8  
{ |.asg  
bStop = true; 
o@o0V  
for(int i=0;i<nStartPos.length;i++) 8`I/\8;H'p  
fileSplitterFetch.splitterStop(); zO@7V>2  
.ty^k@J|]  
U};~ff+  
} Mg7nv\6  
} F.N4Q'2Z  
//负责部分文件的抓取 N;\G=q] 9  
**FileSplitterFetch.java 8y9`xRy  
*/ Cob<N'.  
package NetFox; ;%#.d$cU  
7v{X?86&  
zB/)_AW  
import java.io.*; N:4oVi@Je  
import java.net.*; P#gY-k&Nr  
AK$h S
M  
[{K   
public class FileSplitterFetch extends Thread { ( E8(np  
ZUkrJ'  
e*nT+Rp  
String sURL; //File URL
.u
<i<S  
long nStartPos; //File Snippet Start Position F9N/_H*+  
long nEndPos; //File Snippet End Position mN!5JZ'2  
int nThreadID; //Thread's ID MfJs?N0  
boolean bDownOver = false; //Downing is over @Czj] t`  
boolean bStop = false; //Stop identical .aA8'/  
FileAccessI fileAccessI = null; //File Access interface 
~7kIe+V  
vt(A?$j|A  
1\hh,s  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P&6hk6#  
{ Rt%3\?rf  
this.sURL = sURL; E0SP  
this.nStartPos = nStart; @c>a  
this.nEndPos = nEnd; I: j!A  
nThreadID = id; lZ\Si  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *8WcRx  
} 1cA
4-,YO>  
vk^/[eha  
xJ
0
Q8A  
public void run() ;z>?
- j  
{ |=\w b^l+  
while(nStartPos < nEndPos && !bStop) oo+nqc`,O  
{ eD#R4  
H@j D%  
W-72&\7  
try{ iC$mb~G  
URL url = new URL(sURL); r+#!]wNPe  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y*f5_  
httpConnection.setRequestProperty("User-Agent","NetFox"); c:$W5j('Z  
String sProperty = "bytes="+nStartPos+"-"; `S&$y4|Vs  
httpConnection.setRequestProperty("RANGE",sProperty); |Z"5zL10  
Utility.log(sProperty); r@|{mQOxa  
r )pg9}+  
w^rINPAS  
InputStream input = httpConnection.getInputStream(); N:_U2[V^d  
//logResponseHead(httpConnection); MDyPwv\  
4mqA*c%6S  
7aV(tMzd  
byte[] b = new byte[1024]; D>HX1LV  
int nRead; NHL -ll-R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hYj!*P)uV  
{ ME9jN{ le  
nStartPos += fileAccessI.write(b,0,nRead); _ +"V5
z  
//if(nThreadID == 1) qaj~q(j~C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]jk
aOj  
} t7(#Cuv-  
dHAI4Yf4U  
\nX5$[  
Utility.log("Thread " + nThreadID + " is over!"); K~U5jpc  
bDownOver = true; I_h8)W  
//nPos = fileAccessI.write (b,0,nRead); cTq
}H_hC  
} C}7c:4c  
catch(Exception e){e.printStackTrace ();} !8z,}HUdK  
} V~9s+>  
} 3ZAPcpB2  
^hMJNy&R  
H7I
&Ky  
//打印回应的头信息 @$e!|.{1q  
public void logResponseHead(HttpURLConnection con) RKt#2%FFO  
{ 3T<aGW1  
for(int i=1;;i++) RV&=B%w+  
{ pyf/%9R:d  
String header=con.getHeaderFieldKey(i); }uCC~ <^  
if(header!=null) &idPO{G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j9bn|p$DA  
Utility.log(header+" : "+con.getHeaderField(header)); ,rC$~ &  
else BS6UXAf{|Z  
break; IpRdGT02  
} R _c! ,y  
} NDmTxW#g  
t/3t69\x  
YpGG^;M$  
public void splitterStop() SDW_Y^Tb  
{ E|Q|Nx!6[  
bStop = true; *[Q
FIDn:  
} zx(=ArCRr  
9/@7NNKJ  
3=)!9;uY  
} 8ph*S&H  
<z=d5g{n  
7FTf8  
/* oaK&!$S]  
**FileAccess.java v&8%t 7|  
*//文件访问(定位，写) d=6FL" .o  
package NetFox; a%fMf[Fu  
import java.io.*; j3J\%7^i  
;;3oWsil}  
_>k&,p]y  
public class FileAccessI implements Serializable{ Lwzk<+>w^  
+im>|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ZbZCW:8>k  
RandomAccessFile oSavedFile; zS6oz=  
long nPos; HZ+l){u  
-/7[\S  
XITh_S4fs=  
public FileAccessI() throws IOException SGp}(j>  
{  3g#  
this("",0); BbV@ziL  
} d7*fP S  
Rl%?c5U/$  
: }q~<  
public FileAccessI(String sName,long nPos) throws IOException _UqE -+&  
{ nKO4o8js{{  
oSavedFile = new RandomAccessFile(sName,"rw"); BwpSw\\?@  
this.nPos = nPos; -VO&#Mt5u  
oSavedFile.seek(nPos); ?_VoO  
} 4$wn8!x2|  
3O'6 Ae  
)Gu:eYp+`  
public synchronized int write(byte[] b,int nStart,int nLen) 3T|xUY)G4  
{ $YNWT\
FE  
int n = -1; Fr,qVYf  
try{ O\"k[V?.V  
oSavedFile.write(b,nStart,nLen); zo^34wW^  
n = nLen; [|&V$  
} 9c}mAg
4  
catch(IOException e) a9"1a'  
{ KcK,%!>B  
e.printStackTrace (); k|SywATr  
} o-f;$]yp>  
==?!z<I.d  
|BC/ERms  
return n; A0@E^bG  
} (:spA5  
G%RL8HU  
!L=RhMI  
} BKfkB[*F  
w|AHE  
WkF60'Hf  
/* y;r{0lTB  
**SiteInfoBean.java `> :^c  
*/ Vp.&X 8  
package NetFox; !
UV1OU  
I\,m6=q  
H E'1Wa0r  
public class SiteInfoBean { QR#L1+Hn  
NQdz]o  
0|^/e-^  
private String sSiteURL; //Site's URL Z +vT76g3  
private String sFilePath; //Saved File's Path ~@Wg3'&  
private String sFileName; //Saved File's Name I8s%wY9  
private int nSplitter; //Count of Splited Downloading File W|yFjE&dr  
68 *~5]  
Z.iQ
m{bI  
public SiteInfoBean() ]DO~7p[  
{//nSplitter的缺省值为5 }5??n~:*5  
//default value of nSplitter is 5 ,1!
~@dhs  
this("","","",5); Y!K5?kk  
} '@WpJ{]A  
'PBuf:9lN  
z K+C&X  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %^?yI
 
{ jMP!/t :w  
sSiteURL= sURL; uYu/0fQD  
sFilePath = sPath; %!vgAH4  
sFileName = sName; Cr a@  
this.nSplitter = nSpiltter; \d&/,?,Ey  
I/&uiC{l@  
f0h^ULd  
} Ol@ssm  
t V:oBT*  
$}TK,/W  
public String getSSiteURL() it\U+xu  
{ `-J$7)d@  
return sSiteURL; mx ]a@tu  
} jO9w7u6  
ku&m)'  
'cpO"d?{  
public void setSSiteURL(String value) -<jd/ 5  
{ Tx|}ke
~  
sSiteURL = value; jlA?JB  
} yW!+:y_N_  
?L'4*S]  
_Dv<  
public String getSFilePath() dm+}nQI\  
{ @#?w>38y  
return sFilePath; J:  T  
} | 
WN9&  
*}n)KK7aT  
@S>$y5if  
public void setSFilePath(String value) n1mqe*Mvs/  
{ ?;c&5'7ct  
sFilePath = value; <8SRt-Cr  
} KVC$o+<'`%  
|rhCQ"H  
{ yvKUTq`  
public String getSFileName() -2\%?A6L  
{ j0]|$p  
return sFileName; `O'@T
rI  
} `n{yls7.  
G=Qslrtg  
i]L4kh5
 
public void setSFileName(String value) 1I1Z),  
{ <.l$jW]  
sFileName = value; 
TX%W-J_  
} >@T(^=Q  
uQYBq)p|  
[|NgrU_.  
public int getNSplitter() +=qazE<:0  
{ fK'qc L  
return nSplitter; 2 ~z
o)G0  
} gEBwn
2  
Bv)4YU
 
w2mLL?P  
public void setNSplitter(int nCount) 7H=^~J  
{ 7ql&UIeQ  
nSplitter = nCount; Q~L"Mr8>V  
} `Qc_]CWYH  
} kV mJG#
 
1q&gTvIp  
?d? cD  
/* )iiwxpdw  
**Utility.java 4 <&8`Q  
*/ sY#iGEf  
package NetFox; S[_Hc$7U  
'B$bGQ  
vcsMU|GGh  
public class Utility { @6~OQN  
T5jZd@VT,  
+EnJyli  
public Utility() yzml4/X  
{ o (OC3  
| gou#zi  
7T)J{:+0!|  
} pKM5<1J  
w,CZ*/^  
//线程睡眠 CLU[')H0  
public static void sleep(int nSecond) ,iUYsY  
{ }: W6Bo-|  
try{ 0tzMu#  
Thread.sleep(nSecond); x!<?/I)X  
} nKoc%TNqe  
catch(Exception e) d
_5wMK6O6  
{ 6-'Y*  
e.printStackTrace (); XP$1CWI  
} 'x-PQQ  
} 1HBdIWhHv.  
xzGs%01]  
//日志 @+S5"W  
public static void log(String sMsg) |0wUOs*5  
{ 9%VNzPzf  
System.err.println(sMsg); kp+\3z_  
} D-zqu~f`  
otsINAizgS  
4eOQP  
public static void log(int sMsg) k?Bc^7l:  
{ Dyx3N5?C  
System.err.println(sMsg); ON$^_l/c  
} 4I[g{S nF  
} Q\>Kd N{  
Z~.3)6,z  
Tn# >"Ag  
/* &UW
Sf  
**TestMethod.java )eFq0+6*)  
*/ a*8^M\>m4  
package NetFox; p^LUyLG`  
XOM@Pi#z  
n{~Ws^d  
public class TestMethod { Y^?J3[@  
}tIIA"dZ  
@jE<V=?  
public TestMethod() GUe&WW:Sqk  
{ ///xx/weblogic60b2_win.exe .&53WL[D|  
try{ ,UdTUw~F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ijYSYX@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); wec|~Rc-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8bB'[gJ]{  
fileFetch.start(); J% B(4`  
} 7[l "=  
catch(Exception e){e.printStackTrace ();} Dl3Df u8  
~6nq$(#  
]i=\5FH e  
} >Ic)RPO9  
az(u=}  
|WiK*  
public static void main(String[] args) r+BPz%wM=O  
{ BO b#9r  
new TestMethod(); Ny;(1N|&3  
} &b 2Vt  
} (~r"N?`  
点击下载更多相关资料