http断点续传简单实现（java)

/* r8E)GBH-|  
**SiteFileFetch.java ]2P*Z6Az  
*/ ,s,VOyr @F  
package NetFox; ,2YkQ/>  
import java.io.*; KDX34Fr1  
import java.net.*; \{ui{8+G  
nZ 0rxx[V?  
U&\8~h  
public class SiteFileFetch extends Thread { <X_I`  
3o=K?eOdg  
+5+?)8Ls  
SiteInfoBean siteInfoBean = null; //文件信息Bean n^AQ!wC  
long[] nStartPos; //开始位置 5L}qL?S`x|  
long[] nEndPos; //结束位置 zLxO\R!d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "NamP\hj  
long nFileLength; //文件长度 hkq[xgX  
boolean bFirst = true; //是否第一次取文件 ZsP
T!l,  
boolean bStop = false; //停止标志 t:G67^<3  
File tmpFile; //文件下载的临时信息 C"P40VQoo  
DataOutputStream output; //输出到文件的输出流 ,:QzF"MV  
'bXm,Ed  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1c} %_Z/  
public SiteFileFetch(SiteInfoBean bean) throws IOException f|f9[h'  
{ ,NQucp  
siteInfoBean = bean; D|}%(N@sl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ol~jq;75  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jCMr[ G=  
if(tmpFile.exists ()) Q~A25Jf.  
{ 2=TQU33#  
bFirst = false; Uva b*9vX  
read_nPos(); bI,gNVN=  
} B9RB/vHH  
else -&u2C}4s  
{ &K_"5.7-56  
nStartPos = new long[bean.getNSplitter()]; y[s* %yP3l  
nEndPos = new long[bean.getNSplitter()]; 8)D5loS  
} Ck|3DiRQ  
0OndSa,  
<4{,u1!t  
L"akV,w4p  
} y%21`y&Os  
q7 ;TdQ  
w7?&eF(w(  
public void run() &ESE?{of)  
{ SG{> t*E  
//获得文件长度 ;L5'3+U  
//分割文件 n'yC-;  
//实例FileSplitterFetch SJRiMR_F~  
//启动FileSplitterFetch线程 s^]F4'  
//等待子线程返回 WvN!8*XFM  
try{ y^#jM  
if(bFirst) 8#9d
i  
{ L)5YX-?  
nFileLength = getFileSize(); Jbud_.h9  
if(nFileLength == -1) J3oj}M*  
{ &!uNN|W  
System.err.println("File Length is not known!"); rTiW&#  
} 4|Dxyb>pS  
else if(nFileLength == -2) Z)6gh{B08  
{ s!Xj'H7K  
System.err.println("File is not access!"); U}55;4^LX  
} `[<j5(T  
else G] -$fz  
{ .`OyC'  
for(int i=0;i<nStartPos.length;i++) b{C3r3B8  
{ 5JE8/CbH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R$<LEwjSw  
} 8,BNs5  
for(int i=0;i<nEndPos.length-1;i++) _yq"F#,*  
{ :h1-i  
nEndPos = nStartPos[i+1]; 0Dj<-n{9  
} ;IC:]Zu  
nEndPos[nEndPos.length-1] = nFileLength; HB+\2jEE  
} h\k!X/  
} QfuKpcT&  
]bG8DEwD  
`zNvZm-E  
//启动子线程 p!MOp-;-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }xx[=t=nUf  
for(int i=0;i<nStartPos.length;i++) IS`1}i$1%  
{
{%$eq{~m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xF'9`y^]!@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), t>J 43  
nStartPos,nEndPos,i); ANNfL9:Jy  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OAu?F}O  
fileSplitterFetch.start(); }LDH/# u  
} [-X=lJ:+h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }JXAG/<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N5$L),?\y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?u/Uov@rD  
nEndPos = " + nFileLength); fKzOt<wm  
// fileSplitterFetch[nPos.length-1].start(); G2]/g  
_ECWSfZ  
}yup`R  
//等待子线程结束 JG xuB*}  
//int count = 0; PiMW29B^  
//是否结束while循环 PpPg ~ix*  
boolean breakWhile = false; )_P|_(  
sgdxr!1?y  
eeX^zaKl]  
while(!bStop) | I_,;c  
{ <KF|QE  
write_nPos(); (|_1ku3!  
Utility.sleep(500); #?)g?u%g=  
breakWhile = true; SomA`y+ERn  
F V8K_xj  
sW[8f Z71  
for(int i=0;i<nStartPos.length;i++) \IL/?J 5d  
{ a"^0;a  
if(!fileSplitterFetch.bDownOver) */iD68r|-  
{ 1$Rua  
breakWhile = false; @!0@f'}e  
break; fcd
\{1#u  
} eRkvNI  
} -~O7.E(ok  
if(breakWhile) <]6])f,y\  
break; ,E{z+:Es  
xS%
Z   
T^3_d93}d  
//count++; XK[cbVu  
//if(count>4) zKr\S|yE  
// siteStop(); Hi$J@xU  
} T/DKT1P-  
A`Vz5WB  
8OoKP4,;  
System.err.println("文件下载结束！"); `mTpL^f  
} xSFY8  
catch(Exception e){e.printStackTrace ();} V)M+dhl  
} Q}p+/-U\  
}D_h*9  
~|e?@3_G  
//获得文件长度 RG [*:ReB9  
public long getFileSize() \ct)/  
{ . :Q[Z  
int nFileLength = -1; i3~"qbU%z[  
try{ [5 Mt,skC:  
URL url = new URL(siteInfoBean.getSSiteURL()); HS3]8nJW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T `x:80  
httpConnection.setRequestProperty("User-Agent","NetFox"); TwBwqQ)t  
b/IT8Cm3  
E/mp.f2!  
int responseCode=httpConnection.getResponseCode(); .LDK+c  
if(responseCode>=400) tbHU(#~  
{ ~1xln?Q  
processErrorCode(responseCode); Wk$ 7<gkr  
return -2; //-2 represent access is error !Z978Aub3&  
} >e y.7YG  
}%_h|N  
uMl.}t2uYu  
String sHeader; *I)oDq3  
(uV~1  
Jh2eo+/%  
for(int i=1;;i++) +]^6&MqO  
{ Pt~mpRlH
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R7: >'*F  
//Utility.log(in.readLine()); h|h-<G?>  
sHeader=httpConnection.getHeaderFieldKey(i); [)V&$~xW  
if(sHeader!=null) qdo
JIP{  
{ d;`bX+K  
if(sHeader.equals("Content-Length")) InDISl]  
{ =Nn&$h l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); t(69gF\"  
break; Fm(~Vt;%u  
} (R)\  
} ?0_Bs4O\  
else /fCj;8T3o  
break; B{'x2I#,  
} 5y07@x  
} g_?:G$1H  
catch(IOException e){e.printStackTrace ();} @+LkGrDP  
catch(Exception e){e.printStackTrace ();} qMT7g LB'1  
RD_IGV  
K7 >Z)21  
Utility.log(nFileLength); E6(OEC%,  
16"eyt>  
]Igd<  
return nFileLength; C2RR(n=N^  
} :7&#ej6  
bl. y4  
`p`)D6  
//保存下载信息（文件指针位置） ~e,k71  
private void write_nPos() d&K2\n  
{ )SG+9!AbMZ  
try{ l]Ozy@ Ib  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =KfV;.&  
output.writeInt(nStartPos.length); u4QPO:,a4  
for(int i=0;i<nStartPos.length;i++) 0Lcd@3XL  
{ @i`*i@g  
// output.writeLong(nPos); 7kmU/(8  
output.writeLong(fileSplitterFetch.nStartPos); $Lpt2:.((  
output.writeLong(fileSplitterFetch.nEndPos);
lWj{pyZ  
} o~7~S  
output.close(); f,GF3vu"  
} =Q985)Y&  
catch(IOException e){e.printStackTrace ();} U X)k;h  
catch(Exception e){e.printStackTrace ();} %_xRS  
} siveqz6
h  
4qq+7B  
$]:ycn9l  
//读取保存的下载信息（文件指针位置） FG.MV-G  
private void read_nPos() jt|e?1:vF  
{ $_s"16s  
try{ J@RhbsZn  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /mLOh2T  
int nCount = input.readInt(); 1U[8OM{$  
nStartPos = new long[nCount]; k.nq,  
nEndPos = new long[nCount]; +*"u(7AV  
for(int i=0;i<nStartPos.length;i++) .6Jo1$+  
{ V_pWf5F  
nStartPos = input.readLong(); 3vx*gfr3  
nEndPos = input.readLong(); ^CZ!rOSv  
} {qO[93yg)/  
input.close(); 28qTC?  
} L\d"|87lX  
catch(IOException e){e.printStackTrace ();} S]3K5Z|  
catch(Exception e){e.printStackTrace ();} 4QbDDvRQ^  
} #({0HFSC:j  
ZuIr=`"j  
Vae}:8'}  
private void processErrorCode(int nErrorCode) Pg[XIfBva  
{ X`kTbIZ|  
System.err.println("Error Code : " + nErrorCode); #rSm;'%,  
}  QDCu  
0M^7#),  
!6yoD  
//停止文件下载 6gz !K"S  
public void siteStop() $j61IL3+  
{ [@"~'fu0  
bStop = true; ;=goIsk{Q  
for(int i=0;i<nStartPos.length;i++) nX(2&<  
fileSplitterFetch.splitterStop(); >`Xikn(  
* SH5p  
Ua^#.K  
} B"rV-,n{  
} L{H` t{A  
//负责部分文件的抓取 uan%j
]|q%  
**FileSplitterFetch.java r}k2n s9  
*/ 0k"n;:KM8  
package NetFox; ?@"F\Bv<h  
)xgOl*D  
&NbhQY`k  
import java.io.*; Q)eYJP=W  
import java.net.*; 'p3JYRT$  
R5M/Ho 4
 
$X1T!i[.X  
public class FileSplitterFetch extends Thread { 8Jnb/A}  
kSJWXNC  
&%M!!28X:  
String sURL; //File URL ];& @T\Rj  
long nStartPos; //File Snippet Start Position yhzC 9nTH  
long nEndPos; //File Snippet End Position .U.Knn  
int nThreadID; //Thread's ID &''lOS|  
boolean bDownOver = false; //Downing is over (tQ#('(w  
boolean bStop = false; //Stop identical Pf`HF|NI  
FileAccessI fileAccessI = null; //File Access interface o6LeC*  

~DYUI#x  
N!R>L{H>  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f' |JLhs  
{ TEQs\d  
this.sURL = sURL; lYz{#UX}  
this.nStartPos = nStart; u#9H  
this.nEndPos = nEnd; tkT:5O6  
nThreadID = id; uE{r09^q\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~qFuS933  
} gaFOm9y.e  
+T]/4"^M  
M7U:UV)  
public void run() [n%=2*1p  
{ J
~.8.]gXW  
while(nStartPos < nEndPos && !bStop) Q<4Sd:P`"  
{ ^0oOiZs  
IM-O<T6r[N  
;2Aqztp  
try{ #.1+-^TQk  
URL url = new URL(sURL); {8b6M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (jj=CLe  
httpConnection.setRequestProperty("User-Agent","NetFox"); sfb)iH|sW  
String sProperty = "bytes="+nStartPos+"-"; u-v/`F2wN  
httpConnection.setRequestProperty("RANGE",sProperty); L1P.
@hJ  
Utility.log(sProperty); }<m'Nkz<X  
#0OW0:Q  
XMt)\r.  
InputStream input = httpConnection.getInputStream(); zfS0
M  
//logResponseHead(httpConnection); N]yh8"7X  
 ! @EZ  
Jz"Yb  
byte[] b = new byte[1024]; Rr>nka)U  
int nRead; < cNJrer  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L\)GPTo!x  
{ Y!!w*G9b  
nStartPos += fileAccessI.write(b,0,nRead); :SBB3G)|  
//if(nThreadID == 1) h=<x%sie  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,x(?7ZW>  
} W(~7e?fO  
 862e  
bU$4"_eA B  
Utility.log("Thread " + nThreadID + " is over!"); eK8y'VY  
bDownOver = true; pZeJ$3@vk  
//nPos = fileAccessI.write (b,0,nRead); 7T[Kjn^{Oj  
} 2c)Ez?  
catch(Exception e){e.printStackTrace ();} {=3&_/9s){  
} 94uAt&&b(  
} },r9f MJ  
_x+)Tv  
;ZOu-
B]q  
//打印回应的头信息 JU>F&g/|  
public void logResponseHead(HttpURLConnection con) 'YFy6rds  
{ +!"GYPUXy  
for(int i=1;;i++) 0oT~6BGm  
{ a!?JVhD&  
String header=con.getHeaderFieldKey(i); 8.`*O  
if(header!=null) },eV?eGj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t,D7X1W  
Utility.log(header+" : "+con.getHeaderField(header)); f2*e&+LjTP  
else WdtZ{H  
break; $"
e$#<g  
} (FVHtZi7  
} H\r- ;,&  
@$G{t^&os  
fYxdG|>{u  
public void splitterStop() TzSEQS{  
{ -] @cUx  
bStop = true; q8m[ S4Q]g  
} >6X$iBb0
 
JE~;gz]  
~<.%sVwE  
} }0okyGg>q  
lf`" (:./  
^*g= 65!1  
/* @zs.M-F  
**FileAccess.java ~DJILc  
*//文件访问(定位，写) uW 7Yem&  
package NetFox; 3*8m!gq7s  
import java.io.*; (&o|}"kRq  
>;s!X(6b  
u2o196,Ut  
public class FileAccessI implements Serializable{ j|-{*t{/x  
~pt#'65}:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 qu`F,OG  
RandomAccessFile oSavedFile; |U:VkiKt  
long nPos; (F+]h]KSi  
yd=NafPM  
-`cNRd0n  
public FileAccessI() throws IOException wn Q% 'Eo  
{ 7W.z8>p  
this("",0); O-uf^S4  
} E51'TT9  
w+][L||4c  
=WEWs4V5A  
public FileAccessI(String sName,long nPos) throws IOException ,>3b|-C-  
{ Q=u [j|0mc  
oSavedFile = new RandomAccessFile(sName,"rw"); 4(mRLr%l@`  
this.nPos = nPos; HO}eu  
oSavedFile.seek(nPos); o>^@s4t  
} cv7.=*Kb;  
.22}=z  
=`EVg>+^  
public synchronized int write(byte[] b,int nStart,int nLen) l\6.f_  
{ \R.Fmeko  
int n = -1; ,<O|#`?"@G  
try{ CyKupJ.Fq  
oSavedFile.write(b,nStart,nLen); z{(c-7*  
n = nLen; 
M?v`C>j  
} wDt9Lf O  
catch(IOException e) 82P#C4c+d  
{ $_+.D`vx`  
e.printStackTrace (); g0k{b  
} rd ]dDG  
2#_i_j  
7Um3myXU  
return n; T]lVwj  
} HV[*=Qi  
czcsXBl[  
f)#nXTXeC  
} -~TgA*_5]  
= KJ_LE~)  
MT^krv(G  
/* AiUK#I  
**SiteInfoBean.java *?R<gWCF  
*/ gE$@:j  
package NetFox; w=x [=O  
evE$$# 6R  
D.,~I^W  
public class SiteInfoBean { Senb_?  
+GlG.6  
l~#%j( Yo  
private String sSiteURL; //Site's URL
'-[?iF@l  
private String sFilePath; //Saved File's Path uu
f+M-P  
private String sFileName; //Saved File's Name _xdFQ  
private int nSplitter; //Count of Splited Downloading File dk.VH!uVb  
PbIir=  
</li<1  
public SiteInfoBean() l.%[s6  
{//nSplitter的缺省值为5 3h4'DQ.g  
//default value of nSplitter is 5 EViDMp"  
this("","","",5); ]cP$aixd  
} G]E-2 _t7  
7NP Ny  
/rzZU}3[  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @YI-@  
{ BE,H`G #h  
sSiteURL= sURL; Nrfj[I  
sFilePath = sPath; HyJ&;4rf  
sFileName = sName; e"]DIy4s  
this.nSplitter = nSpiltter; b\^9::oY  
2@?\"kR"!  
U,tWLX$@  
} cE7IHQ  
:M\3.7q  
I7HP~v~  
public String getSSiteURL() :eL ja*  
{ +*Pj,+;W  
return sSiteURL; 5tcJTz  
} &)F#cVB  
jbs)]fqC;  
OO-b*\QW  
public void setSSiteURL(String value) oWcBQ|   
{ ;0Mg\~T~'  
sSiteURL = value; > m##JzWLr  
} NSDls@m  
O_|p{65
  
PJ'.s  
public String getSFilePath() 8BggK6X  
{ ?vocI  
return sFilePath; )jm u*D5N  
} 9p%8VDF=  
Pskg68W  
H<C+rAIb  
public void setSFilePath(String value) nI<Ab_EB  
{ |emZZj  
sFilePath = value; ]?n~?dD{]  
} j[&C6l+wH  
yUlYf#`H  
p'YNj3&u  
public String getSFileName() z]0UW\S/  
{ F'3-*>]P  
return sFileName; vw
/X  
} x[1(cj  
BZs?tbf  
\"AzT{l!;  
public void setSFileName(String value) zR6^rq*  
{ ` EgO&;1D)  
sFileName = value; kz?
m `~1  
} FX:'38-fk  
X.hVMX2B  
K0z@gWGE  
public int getNSplitter() mFeoeI,Jv  
{ U(u$5  
return nSplitter; V0a)9\x(\  
} _%6Vcy  
d ~3GEK  
N Uq'96{Y  
public void setNSplitter(int nCount) XdGA8%^cY  
{ [XDr-5Dm  
nSplitter = nCount; #`b5kqQm  
} k5TPzm=y{  
} X7{ h/^  
;sfk@ec  
E|5lm  
/* drEND`,@6|  
**Utility.java Yn1CU  
*/ t9+ME|  
package NetFox; V.12  
u<a =TPAU  
sN9 SuQ  
public class Utility { &s<'fSI  
/6d:l>4  
0 |Y'@&  
public Utility() )R]gJ_,c  
{ m9m]q&hx  
[m{uJdj\  
k{d)'\FM  
} BuIly&qbm<  
r4(Cb_  
//线程睡眠 ju%t'u\'  
public static void sleep(int nSecond) P},d`4Ty@  
{ !>gu#Q{\-  
try{ 4KCJ(<p|  
Thread.sleep(nSecond); Ceco^Mw  
} (b4;c=<[{  
catch(Exception e) @gHWU>k,A  
{ - |j4u#z  
e.printStackTrace (); TWk1`1|  
} 2$%E:J+2:$  
} @N,I}_9-  
okv`v ({  
//日志 sCwX|  
public static void log(String sMsg) EABy<i  
{  cnwpd%]o  
System.err.println(sMsg); 3^J~ts{*  
} kEpCF:@A  
9;k!dM  
SFRQpQ06  
public static void log(int sMsg) o,;Hb4Eu  
{ Lr}>Md  
System.err.println(sMsg); xBW{Wy
h  
} [!CIBK99  
} ZJeTx.Gi6  
v9K{oB  
~[d|:]  
/* m_n*_tX  
**TestMethod.java 6fr@y=s2:  
*/ 'AjDB:Mt$  
package NetFox; UM QsYD)  
56Gc[<nR  
("$ ,FRTQ:  
public class TestMethod { __N#Y/e ]  
5\|u] ~b  
M4m90C;d
q  
public TestMethod() 1=.+!Tg  
{ ///xx/weblogic60b2_win.exe ,}hJ)  
try{ &@anv.D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0zvA>4cq)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9X6l`bo'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dDoKmuY>5  
fileFetch.start(); #Z.2g].  
} lqe71](sK8  
catch(Exception e){e.printStackTrace ();} t)hAD_sf  
m:A1wL4c6  
GI40Ztms  
} y8QJ=v* B  
n'-?CMH`  
=TzmhX5  
public static void main(String[] args) }|Wn6X  
{ |K
Qkmc  
new TestMethod(); )^'g2gVK+p  
} Z(=UZI?  
} t@1bu$y  
点击下载更多相关资料