http断点续传简单实现（java)

/* _1aGtX|W  
**SiteFileFetch.java g
\Ak;03n  
*/ 'Dath>Y=  
package NetFox; &+01+-1hW  
import java.io.*; 9cG<hX9`F  
import java.net.*; ^]>aHz9  
%D`o  
yS!(Ap  
public class SiteFileFetch extends Thread { 8O7Yv<  
=xL)$DTg)  
_7"5wB?|+  
SiteInfoBean siteInfoBean = null; //文件信息Bean /aYpIMi9}  
long[] nStartPos; //开始位置 8.QSqW7t  
long[] nEndPos; //结束位置 bAEg$A  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 CE ~@}`  
long nFileLength; //文件长度 _okWQvdH  
boolean bFirst = true; //是否第一次取文件 (?>cn_m  
boolean bStop = false; //停止标志 KxIyc7.  
File tmpFile; //文件下载的临时信息 M&KyA  
DataOutputStream output; //输出到文件的输出流 +Rwx%=  
wfR&li{  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） or2|O#=  
public SiteFileFetch(SiteInfoBean bean) throws IOException /:Lu_)5   
{ E7nFb:zlV  
siteInfoBean = bean; _w!a`w*3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;hHi@Z9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 20tO#{Li  
if(tmpFile.exists ()) aC!EWgwW[  
{ .WX,Nd3@  
bFirst = false; wvN
`R  
read_nPos(); <{Q'&T  
} |quij0_'e  
else F}Srn
;V  
{ X(Qu{HhI  
nStartPos = new long[bean.getNSplitter()]; 632
bN
=>  
nEndPos = new long[bean.getNSplitter()]; z wk.bf>m  
} Y3Oz'%B  
@MbVWiv  
fThgK;Qy'U  
n?xTkkr0  
} tU@zhGb  
"35A/V  
]*N1t>
fb  
public void run() c5% 6Y2W0  
{ e,gyQjJR  
//获得文件长度 QJGKQ2^ n  
//分割文件 @?kJ).  
//实例FileSplitterFetch S,{tV=&m]  
//启动FileSplitterFetch线程 e,0-)?5R  
//等待子线程返回 3n]79+w@z  
try{ * F4UAQzYb  
if(bFirst) nP3 E  
{ t;NV $!!  
nFileLength = getFileSize(); `yO'[2  
if(nFileLength == -1) HrM$NRhu  
{ rD &D)w  
System.err.println("File Length is not known!"); O_~7Glu  
} Yh<WA>=  
else if(nFileLength == -2) nZk+  
{ 4aUiXyr*2  
System.err.println("File is not access!"); =QOg 6  
} 5(m(xo6  
else `y
iC=$*[  
{ |~0UM$OB^3  
for(int i=0;i<nStartPos.length;i++) F@YKFk+a  
{ BuOgOYh9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Fhf<T`  
} EGVM)ur  
for(int i=0;i<nEndPos.length-1;i++) r! %;R?c  
{ ?C-Towo=i  
nEndPos = nStartPos[i+1]; 78 f$6J q  
} kz}R[7  
nEndPos[nEndPos.length-1] = nFileLength; U7h(`b  
} B1!kn}KlL{  
} x;s0j"`Jb  
lLhL`C!  
Qzv
Hm1,@  
//启动子线程 oUZoj2G1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2JGL;U$  
for(int i=0;i<nStartPos.length;i++) EgjR^A1W2  
{ Xf[kI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 88s/Q0l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3SttHu0X  
nStartPos,nEndPos,i); c9"r6j2m5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^h' Sla  
fileSplitterFetch.start(); $g0+,ll[6  
} ]=pR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S$,'Q^~K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u\yVR$pQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w;6bD'.>;  
nEndPos = " + nFileLength); Lh.b5Q|  
// fileSplitterFetch[nPos.length-1].start(); zi9[)YqxPH  
g4p  
RE2&mYt  
//等待子线程结束 6w8">~)Z  
//int count = 0; Yr.sm!xA  
//是否结束while循环 ^TY;Zp  
boolean breakWhile = false; B;>{0 s  
46@{5)Tq  
: 18KR*;p  
while(!bStop) !9Z r;K~\  
{ DyJ.BQdk)  
write_nPos(); AlE8Xu9UB  
Utility.sleep(500); \_V-A f{6  
breakWhile = true; /P|fB]p  
Fb`a~c~s  
<7SpEVQ  
for(int i=0;i<nStartPos.length;i++) t_^X$pL  
{ sUJ%x#u}Fk  
if(!fileSplitterFetch.bDownOver) )SF}2?7e  
{ `{k"8#4:qA  
breakWhile = false; 1RcSTg  
break; U1_@F$mq<  
} P262Q&.}d  
} H,fZ!8(A_)  
if(breakWhile) )L{ghy  
break; ^
DeERB  
#'D" 'B  
eV:9y  
//count++; C?v[Z]t  
//if(count>4) ZYU=\  
// siteStop(); `*", <  
} 6tHO!`}1  
M5nWVK7c  
)c n+1R  
System.err.println("文件下载结束！"); Qd}m`YW-f$  
} )a9 ]US^  
catch(Exception e){e.printStackTrace ();} >(uZtYM\j  
} y&}E~5O  
*4+3ObA  
Vtc36-\1*  
//获得文件长度 *_a@z1  
public long getFileSize() {"oxJ`z4  
{ "Ve.cP,7(  
int nFileLength = -1; CYYkzcc^  
try{ `ps)0!L L`  
URL url = new URL(siteInfoBean.getSSiteURL()); |(5W86C,ju  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kpL@P oQ/r  
httpConnection.setRequestProperty("User-Agent","NetFox"); FuI73  
*f&EoUk}F  
{!6/x9>  
int responseCode=httpConnection.getResponseCode(); |8mhp.7  
if(responseCode>=400) t@u7RL*n:<  
{ w
(kf  
processErrorCode(responseCode); pyLRgD0 g  
return -2; //-2 represent access is error kB?al#`  
} ]f+ csB  
p' M%XBu  
I2nF-JzD2a  
String sHeader; 3vcO!6Z5  
t`*!w|}(1  
~\{^%~[48  
for(int i=1;;i++) *Qugv^-  
{ ~U;rw&'H  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); S
*j6OwZ
 
//Utility.log(in.readLine()); hxCvk/7sT  
sHeader=httpConnection.getHeaderFieldKey(i); }|P
Y!O  
if(sHeader!=null) /}Jj
 
{ ono4U.C9  
if(sHeader.equals("Content-Length")) PH"n{lW.T  
{ :Y9N
Lbv  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f$NMM >z  
break; I%- " |]$  
} t]7&\ihZi~  
} n6s}ww)  
else n1!?"m!  
break; *OuStr \o  
} )Ke*JJaq  
} aLIBD'z  
catch(IOException e){e.printStackTrace ();} X]\ \,  
catch(Exception e){e.printStackTrace ();} x|yEtO&  
vAyFmdJ^  
CPNL 94x  
Utility.log(nFileLength); >3z5
ww  
B}PIRk@a1  
8\{^|y9-  
return nFileLength; X]P:CY  
} 0eK*9S]  
W 4F\}A  
|V<h=D5W  
//保存下载信息（文件指针位置） 035rPT7-2-  
private void write_nPos() v|U(+O  
{ G:zua`u[  
try{ Me 5_4H&Sg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &|/| ''A)  
output.writeInt(nStartPos.length); 0
GJn_@hr  
for(int i=0;i<nStartPos.length;i++) [Q=dCX9%  
{ 'fW6 .0fXa  
// output.writeLong(nPos); FQ=@mjh  
output.writeLong(fileSplitterFetch.nStartPos); zN  [2YJ$  
output.writeLong(fileSplitterFetch.nEndPos); eImn+_ N3  
} 0v9rv.Y"  
output.close(); Iu$K i  
} lP<:tR~K  
catch(IOException e){e.printStackTrace ();} '` pDngX  
catch(Exception e){e.printStackTrace ();} G "73=8d  
} OKoan$#sn  
OE}*2P/M>  
dd]/.Z  
//读取保存的下载信息（文件指针位置） l
sJnI|  
private void read_nPos() !?|Th5e  
{ ANgw"&&>(  
try{ 9W(dmde>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1Tu *79A  
int nCount = input.readInt(); .'Vww  
nStartPos = new long[nCount]; 8']9$#  
nEndPos = new long[nCount]; *4V=z#  
for(int i=0;i<nStartPos.length;i++) \hB5@e4i2  
{ hi
Qha5  
nStartPos = input.readLong(); V7/I
>^X  
nEndPos = input.readLong(); Q[nEsYP  
} k{'0[,mx#  
input.close(); !Y-98<|b M  
} |+T1XYG5  
catch(IOException e){e.printStackTrace ();} ztw@Y|<2  
catch(Exception e){e.printStackTrace ();} V O3x~E  
} z<yU-m2h
 
q5?# 3T=  
JU4qzi  
private void processErrorCode(int nErrorCode) t+eVR8  
{ l8?>>.<P=  
System.err.println("Error Code : " + nErrorCode); 2$Tj84'X  
} #5f-`~^C{  
y3h/IpT  
-{ H0g]  
//停止文件下载 5=f|7yl  
public void siteStop() K

N*  
{ eM+!Y>8Y  
bStop = true; hNzB4p  
for(int i=0;i<nStartPos.length;i++) |o\8  
fileSplitterFetch.splitterStop(); y~FV2$  
h=:Q-?n-  
VY3&  
} w
u)w   
} m}X`> aD/  
//负责部分文件的抓取 1;{Rhu7* k  
**FileSplitterFetch.java 2RX!V@z.G  
*/ sQ fFu  
package NetFox; YGrg  
zRyuq1Zyc,  
gXjV?"^kUl  
import java.io.*; <kCU@SK
 
import java.net.*; 3? HhG  
\Cii1\R=  
}5hqDBK?  
public class FileSplitterFetch extends Thread { (2=Zm@Zpf  
V>b\[(=s  
?:)
]h c  
String sURL; //File URL ?O8ViB?2  
long nStartPos; //File Snippet Start Position +u3=dj"[  
long nEndPos; //File Snippet End Position h-%R<[  
int nThreadID; //Thread's ID nX=$EQiH  
boolean bDownOver = false; //Downing is over t]YC"%[S  
boolean bStop = false; //Stop identical 0|a(]a}V*j  
FileAccessI fileAccessI = null; //File Access interface '#&os`mQ  
{|'E  
ZSG
9t2qlv  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9<>wIl*T`  
{ ^pYxKU_O  
this.sURL = sURL; QnJZr:4b  
this.nStartPos = nStart; T87m?a$  
this.nEndPos = nEnd; gntxNp[9T  
nThreadID = id; w/kt3Lw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 I= &stsH  
} .dav8n*  
RS^lKJ1 U  
L>3x9  
public void run() eN^qG 42  
{ 43@{JK9G  
while(nStartPos < nEndPos && !bStop) ;S>])
5<  
{ (Kv#m 3~  
m8o(J\]  
7eiV{tYF  
try{ %;rHrDP(>  
URL url = new URL(sURL); *#C+iAF|)'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l
k( }-  
httpConnection.setRequestProperty("User-Agent","NetFox"); WUh$^5W  
String sProperty = "bytes="+nStartPos+"-"; h"/<?3{  
httpConnection.setRequestProperty("RANGE",sProperty); Zd')57{  
Utility.log(sProperty); 1#ft#-g}
 
@9lUSk^9  
P9vA7[  
InputStream input = httpConnection.getInputStream(); #':fkIYe'  
//logResponseHead(httpConnection); {62n7'U{  
z&fwE$Nm  
fP(d8xTx2y  
byte[] b = new byte[1024]; m+Rv+_R  
int nRead; K[!&b0O  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [_Qa9e  
{ ;oc&Hb  
nStartPos += fileAccessI.write(b,0,nRead); IWY;="  
//if(nThreadID == 1) =Xqc]5[i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IyWI5Q"t  
} ])nPPf  
Y4v|ko`l%  
OR;uqV@  
Utility.log("Thread " + nThreadID + " is over!"); o}* hY"&  
bDownOver = true; MpF$xzh  
//nPos = fileAccessI.write (b,0,nRead); %y@Hh=  
} p{j.KI s7  
catch(Exception e){e.printStackTrace ();} [m|YWT=  
} .n~M(59  
} Np"exFqN k  
j
'HZ\_  
Bq$rf < W  
//打印回应的头信息 R~S
;sJ& c  
public void logResponseHead(HttpURLConnection con) &FF"nE*  
{ [rSR:V?"a  
for(int i=1;;i++)  [D<1CF  
{ C,N
Jb+J  
String header=con.getHeaderFieldKey(i); /JWGifH  
if(header!=null) ybY]e; v*O  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ZOZ+Y\uU  
Utility.log(header+" : "+con.getHeaderField(header)); eep1I :N  
else opc/e  
break; ~NpA".PB  
} A}3=561F?5  
} Vz=PiMO  
-(~!Jo_*'  
"-vW,7y  
public void splitterStop() z}*9uZ  
{ -De9_0#R  
bStop = true; -i%e!DgH  
} _N{RVeO  
$3s@}vLd  
CD~z=vlK-  
} ~wkj&yVT  
CnG+Mc^  
w%JTTru  
/* i?
 K|TC`  
**FileAccess.java =5(>q5Z*  
*//文件访问(定位，写) $w);5o  
package NetFox; {M^3m5.^  
import java.io.*; %nV]ibp2)  
Cd>WUw  
2AO~HxF  
public class FileAccessI implements Serializable{ JYW)uJ  
.K
p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >8qQK r\"  
RandomAccessFile oSavedFile; paD!Z0v&  
long nPos; 7r~~Y%=C|  
Lcg)UcB-#  
-T[lx\}  
public FileAccessI() throws IOException [YUv7|\  
{ J 
/f  
this("",0); JNJ=e,O,  
}  y"H*%]  
/XzH?n/{R  
5*,f Fib  
public FileAccessI(String sName,long nPos) throws IOException 9mmCp&~Z  
{ ucG@?@JENm  
oSavedFile = new RandomAccessFile(sName,"rw"); 6 1F(
<!  
this.nPos = nPos; 93` AWg/T  
oSavedFile.seek(nPos); 3v5%y'  
} ,^eYlmT>6
 
\ywXi~+kUv  
iC98_o_9  
public synchronized int write(byte[] b,int nStart,int nLen) f;xkT  
{ y&?
6FY  
int n = -1; C'o64+W^  
try{ Zw ^kmSL"  
oSavedFile.write(b,nStart,nLen); !AKg m'Nw  
n = nLen; 3G`aHTWk  
} z6w3"9Um  
catch(IOException e) _YLfL  
{ lna}@]oR  
e.printStackTrace (); =A!@6Nw  
} .`4{9?bR  
:"xzj<(  
bqnNLs<N  
return n; "hzB9*"t  
} /#VhkC _  
t\%HX.8[;%  
~1W x=  
} }}>q2y  
32/MkuY^u  
,z-}t& _t  
/* K%F,='P}  
**SiteInfoBean.java $0lD>yu  
*/ MBhWMC
N2  
package NetFox; BE_ay-  
OVhE??#  
|!"`MIw,  
public class SiteInfoBean { r?Wk<>%>  
.xH5fMj,"  
83Q4On  
private String sSiteURL; //Site's URL (
+FfB"3]  
private String sFilePath; //Saved File's Path GJtZ&H  
private String sFileName; //Saved File's Name &'}RrW-s  
private int nSplitter; //Count of Splited Downloading File 17G'jiYH  
TTt#a6eJ  
*22nVKi{  
public SiteInfoBean() yl1gx  
{//nSplitter的缺省值为5 C86J IC"  
//default value of nSplitter is 5 a+!tT!g&I  
this("","","",5); 7lBAxqr2  
} .QN>z-YA6:  
pnbIiyV  
wT:b\km:!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t-0a7 1#e  
{ -< &D  
sSiteURL= sURL; cxr=k%~}J  
sFilePath = sPath; INi
]R^-  
sFileName = sName; I.94v #r  
this.nSplitter = nSpiltter; -U/c\-~fU  
tjluk  
+(1zH-^.  
} )XzI #iQ  
X  .5aMm  
fvF?{k>~}  
public String getSSiteURL() ( 8c9 /7h  
{ /|eA9 ]  
return sSiteURL; jg\Z;_!W  
} ZfgJ.<<  
N,;5{y1;J  
S7L=#+Z  
public void setSSiteURL(String value) Ksy -e{n  
{ j&Wl0  
sSiteURL = value;  oze&  
}
~?FpU  
Ju :CMkv  
s!}ne"&0  
public String getSFilePath() [3--(#R\}?  
{
7TDy.]  
return sFilePath; 86mp=6@  
} |]ZYa.+:  
=MLcm^b  
OC<5E121>Y  
public void setSFilePath(String value) .P MZX%*v  
{ J1:1B,^y  
sFilePath = value; 1PP $XJtyD  
} M#=] k  
cQ"~\  
}C>{uXv  
public String getSFileName() @Q/-s9b  
{ 82QGS$0V  
return sFileName; jr!?v<NoX  
} MvWaB  
x`dHJq`_g  
%e(z/"M=`  
public void setSFileName(String value) 6N;wqn  
{ 45MLt5^|  
sFileName = value; D?8rO"  
} :C65-[PSdO  
A0q|J/T  
3T}izG]  
public int getNSplitter() ],J
EBt  
{
XoCC/  
return nSplitter; eZdu2.;<  
} JZD[NZ<  
=<X?sj5  
.NvQm]N0.  
public void setNSplitter(int nCount) g47-db"5  
{ W034N[9  
nSplitter = nCount; |<.lW  
} +{W>i;U  
} 3rc
KzS7  
X90J!  
.D:Z{|.1  
/* Z<SLc,]^  
**Utility.java JA'h4AXk  
*/ %JHGiCv|  
package NetFox; )p~BQ~eip;  
^*S)t. "  
@g$Gti  
public class Utility { N%"Y  
}`v~I4i  
"Za>ZRR  
public Utility() k=B]&F  
{ (jFGa2{  
YH%'t= <m  
SOi*SwQ8  
} oNU0 qZ5  
tdSfi<y5I  
//线程睡眠 Ar:*oiU  
public static void sleep(int nSecond) !2'jrJG
c  
{ L?Qg#YSd~  
try{ ( |PAx(  
Thread.sleep(nSecond); \CXQo4P  
} :I:!BXQT$  
catch(Exception e) 4x;/HEb7?  
{  ?kZTI (  
e.printStackTrace (); {FIXc^m'  
} %QKRFPYhS  
} 00SbH$SU  
x7<\]94  
//日志 =}v}my3y"  
public static void log(String sMsg) L2pp6bW  
{ )d$glI+  
System.err.println(sMsg);
HN.3  
} u\LFlX0sO  
q|v(Edt|_[  
3'c0#h@VD  
public static void log(int sMsg) T:IW%?M  
{ N#Zhxu,g!  
System.err.println(sMsg); ^H2-RBE#  
} z-LB^kc8oQ  
} HKqwE=NZ  
l
d^=#]g  
\z$p%4`E@  
/* Ka6,<C o  
**TestMethod.java
|d*&y#kV  
*/ ewfP G,S  
package NetFox; PB/IFsJ  
S6+y?,^  
$P
(v{W)  
public class TestMethod { Q`rF&)Q5  
VGceD$<  
|ZCn`9hvn  
public TestMethod() .GsO.#p{  
{ ///xx/weblogic60b2_win.exe ;B?DfWX  
try{ \L(*]:EP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #DN0T' B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); awOd_![c'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cu%
C"  
fileFetch.start(); i%g#+Gw  
} >layJt
  
catch(Exception e){e.printStackTrace ();} +> WM[o^I  
AwTJJ0>  
\uXcLhXN  
} j~+>o[c  
)E,\H@A  
y
-j\zK  
public static void main(String[] args) 8:#rA*Y  
{ qOUqs'7/]  
new TestMethod(); aAA9$  
} 3nu^l'WQ  
} w^#L9i'v'  
点击下载更多相关资料