http断点续传简单实现（java)

/* qLCR] _*  
**SiteFileFetch.java
dI2 V>vk  
*/ y9;Yivr)  
package NetFox; =vPj%oLp'a  
import java.io.*; lk!@?  
import java.net.*; =-T]3!   
fox6)Uot  
omFz@  
public class SiteFileFetch extends Thread { @7u0v  
[m -bV$-d  
pw#-_  
SiteInfoBean siteInfoBean = null; //文件信息Bean @L`jk+Y0vF  
long[] nStartPos; //开始位置 >sF)BoLc  
long[] nEndPos; //结束位置 S@Y39  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7nSxi+6e  
long nFileLength; //文件长度 fOHxtHM  
boolean bFirst = true; //是否第一次取文件 5N]
"~w*  
boolean bStop = false; //停止标志 jylD6IT  
File tmpFile; //文件下载的临时信息 UBs4K*h|  
DataOutputStream output; //输出到文件的输出流 QnDg6m)+  
i@q&5;%%  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )_:NLo:  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1cDF!X]  
{ ~rm_vo  
siteInfoBean = bean; /xQTxh1;K  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NRuNKl.v  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F
u~j8K  
if(tmpFile.exists ()) o4;(Zi#Z  
{ gr{ DWCK  
bFirst = false; z{543~Og59  
read_nPos(); ]iWRo'  
} {vj)76%y  
else "~nZ GiK  
{ Zfw,7am/  
nStartPos = new long[bean.getNSplitter()]; *Ly6`HZ9  
nEndPos = new long[bean.getNSplitter()]; 5(2;|I,T  
} 0_/[k*Re  
y} '@R$  
2!\DPX  
JC"z&ka  
} eEKf|I  
K:M8h{Ua  
=D(j)<9$A  
public void run() h(4v8ae  
{ AX INThJ  
//获得文件长度 ]|@^1we  
//分割文件 "4Nt\WQ  
//实例FileSplitterFetch <q836]aaA  
//启动FileSplitterFetch线程 XZf$K_F&M  
//等待子线程返回 jdN`mosJ  
try{ YUb_y^B^  
if(bFirst) T|$H#n}  
{ Y2TtY;  
nFileLength = getFileSize(); ,6/V"kqIP  
if(nFileLength == -1) u +hX  
{ ZcsZ$qt^  
System.err.println("File Length is not known!"); y5r4&~04  
} R_KH"`q  
else if(nFileLength == -2) $qiya[&G4  
{ 9
sP0
D  
System.err.println("File is not access!"); #tHK"20  
} :s,Z<^5a)g  
else ~u{uZ(~
  
{ SM'|+ d  
for(int i=0;i<nStartPos.length;i++) zA 3_Lx!  
{ kM6 Qp  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NbobliC=  
} e.>P8C<&  
for(int i=0;i<nEndPos.length-1;i++) #E[0ys1O  
{ 9?$i?  
nEndPos = nStartPos[i+1]; (Z*!#}z`  
} .`lCWeHN  
nEndPos[nEndPos.length-1] = nFileLength; f3;5Am  
} >?b!QU*a  
} #WuBL_nZ~  
u, ff>/1  
s7<AfaJPF  
//启动子线程 #spCtZE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >z03{=sAN  
for(int i=0;i<nStartPos.length;i++) ^~dWU>  
{ ]d]]'Hk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dM5-;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,}PgOJZ  
nStartPos,nEndPos,i); a#4?cEy  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bOB\--:]  
fileSplitterFetch.start(); }EPY^VIw  
} [GR;?R5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _w{Qtj~s|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KXy6Eno  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $`c:&  
nEndPos = " + nFileLength); 9Na$W:P c  
// fileSplitterFetch[nPos.length-1].start(); sx%[=g+<2(  
D-c4EV  
PsYpxNr  
//等待子线程结束 9p/Bh$vJ  
//int count = 0; rsQtMtS2  
//是否结束while循环 Z r8*et  
boolean breakWhile = false; S!UaH>Rh  
53D]3  
zdYjF|  
while(!bStop) \<' ?8ri#  
{ 2:kH[#  
write_nPos(); Ie_wHcM<  
Utility.sleep(500); +R&gqja  
breakWhile = true; paK2xX
8E  
Q?vlfZR`8  
(e~Nq  
for(int i=0;i<nStartPos.length;i++) X, n:,'  
{ 6'/ #+,d'  
if(!fileSplitterFetch.bDownOver) D^O@'zP=At  
{ y0#2m6u  
breakWhile = false; \85i+q:LuA  
break; gJXaPJA{  
} }OUtsh]y  
} AKC`TA*E  
if(breakWhile) \~W'v3:W  
break; 8=l%5r^cq  
kj_c%T ]/  
wp_0+$?s  
//count++; Upe%r
C(  
//if(count>4) u_enqC3  
// siteStop(); ? t|[?  
} nUO0Ce
 
2ESo2  
]DcFySyv  
System.err.println("文件下载结束！"); HtFDlvdy]  
} RP"kC4~1  
catch(Exception e){e.printStackTrace ();} aOp\91  
} wT@og|M  
d-qUtgqV86  
b9krOe*j  
//获得文件长度 S'" Df5  
public long getFileSize() 6Oq7#3]  
{ UN
Yqft4  
int nFileLength = -1; +%'(!A?*`  
try{ Da|z"I x  
URL url = new URL(siteInfoBean.getSSiteURL()); mt .sucT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }7Uoh(d  
httpConnection.setRequestProperty("User-Agent","NetFox"); lN@o2QX  
^!d3=}:
0  
iTwm3V P  
int responseCode=httpConnection.getResponseCode(); ;pAK_>
 
if(responseCode>=400) GOPfXtkC  
{ d=(mw_-
?  
processErrorCode(responseCode); LoV<:|GTI  
return -2; //-2 represent access is error jp,4h4C^)  
} ]Um/FAW  
jd:6:Fm  
 R&&4y 7  
String sHeader; A^g(k5M*  
Nb\4 /;#  
F5<Hm_\:  
for(int i=1;;i++) V0@=^Bls  
{ LVGe]lD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }#fbbtd  
//Utility.log(in.readLine()); ]M=&+c>H~  
sHeader=httpConnection.getHeaderFieldKey(i); aN?zmkPpov  
if(sHeader!=null) /: "1Z]@  
{ <)9y{J}s:  
if(sHeader.equals("Content-Length")) )`:UP~)H  
{ ]Ze1s02(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )
7F/O3Tq  
break; 0kh6@y3  
} M%HU4pTW#o  
} q~3>R=t  
else ye&;(30Oq  
break; 9*gZ-#  
} ~ljXzD93Z  
} 0J9x9j`&j  
catch(IOException e){e.printStackTrace ();} lA]8&+,
ZM  
catch(Exception e){e.printStackTrace ();} ?,mmYW6TjB  
kP:!/g  
iS^QTuk3%  
Utility.log(nFileLength); uRvP hkqm  
,+k\p5P  
[y(MCf19  
return nFileLength; )nkY_'BV  
} 4(+PD&_J  
%b$>qW\*&  
Et$2Y-L.  
//保存下载信息（文件指针位置） ^8WRqQdx  
private void write_nPos() t.<i:#rj>l  
{ 4?kcv59  
try{ ^#pEPVkY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); teRTu  
output.writeInt(nStartPos.length); XFl6M~ c  
for(int i=0;i<nStartPos.length;i++) >MZ/|`[M  
{ c 9Mz]1@f  
// output.writeLong(nPos); z/-=%g >HA  
output.writeLong(fileSplitterFetch.nStartPos); d]9z@Pd
 
output.writeLong(fileSplitterFetch.nEndPos); 2/?|&[  
} ch]IzdD  
output.close(); Q &
8-\  
} }jXfb@`K  
catch(IOException e){e.printStackTrace ();} O
-wzz  
catch(Exception e){e.printStackTrace ();} x2xRBkRg=  
} sJZiI}Xc  
[agMfn  
,tFg4k[  
//读取保存的下载信息（文件指针位置） YK_7ip.a[  
private void read_nPos() )~>YH*g  
{ L(-4w+  
try{ 00
(\ZUj  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /ZX}Nc g  
int nCount = input.readInt(); 6ujWNf  
nStartPos = new long[nCount]; m67V_s,7B  
nEndPos = new long[nCount]; Yy8g(bU  
for(int i=0;i<nStartPos.length;i++) 4W75T2q#  
{ 2?C)&  
nStartPos = input.readLong(); wYea\^co  
nEndPos = input.readLong(); /vt3>d%B;  
} :gv"M8AP  
input.close(); F59 TZI  
} W9&=xs6  
catch(IOException e){e.printStackTrace ();} }e1ZbmW  
catch(Exception e){e.printStackTrace ();} &]Tmxh(  
} +{]j]OP  
WJi]t93  
]Ljf?tk  
private void processErrorCode(int nErrorCode) %d@z39-;  
{ [),ige  
System.err.println("Error Code : " + nErrorCode); C!gZN9-  
} F|8&  
Py<}S-:  
gGYKEq{j(  
//停止文件下载 +`4A$#$+y  
public void siteStop() T{"(\X$  
{ lE;!TQj:X  
bStop = true; bA 2pbjg=  
for(int i=0;i<nStartPos.length;i++) @Qe0! (_=  
fileSplitterFetch.splitterStop(); btB%[]  
9c],<;{'  
637: oT_`O  
} ceA9){  
} }V>T
M{  
//负责部分文件的抓取 U$g?!Yl0  
**FileSplitterFetch.java ~DWl s.  
*/
vO=fP_  
package NetFox; cQ|NJ_F{1  
4-w{BZuS  
ZCw]m#lS  
import java.io.*; e20-h3h+  
import java.net.*; $G>.\t  
]:;&1h3'7  
}H4RR}g  
public class FileSplitterFetch extends Thread { 'w/hw'
F6  
]9-\~Mwh  
al0L&z\  
String sURL; //File URL XW9!p.*.U  
long nStartPos; //File Snippet Start Position ,4rPg
]r@  
long nEndPos; //File Snippet End Position nN;u,}e  
int nThreadID; //Thread's ID zs;JJk^  
boolean bDownOver = false; //Downing is over a*;b^Ze`v  
boolean bStop = false; //Stop identical ?2a$*(  
FileAccessI fileAccessI = null; //File Access interface yZ:qU({KhD  
iso4]>LF  

@HW*09TG  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ESs\O?nO  
{ :Tc^y%b0  
this.sURL = sURL; iLT}oKF2N;  
this.nStartPos = nStart; 'qi}|I  
this.nEndPos = nEnd; ^Cmyx
3O^  
nThreadID = id; 9F
lb|G%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 RSds8\tk  
} )jj0^f1!j  
J,G lIv.A  
QJNFA}*>  
public void run() \v{=gK  
{ V~bD)?M  
while(nStartPos < nEndPos && !bStop) X]=t>
 
{ $e\M_hp*J  
(hsl~Jf  
)"LJ hLg  
try{ m|# y >4  
URL url = new URL(sURL); ivPg9J1S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jpOp
.  
httpConnection.setRequestProperty("User-Agent","NetFox"); PFR:>^wK2  
String sProperty = "bytes="+nStartPos+"-";
0V]s:S  
httpConnection.setRequestProperty("RANGE",sProperty); l%ZhA=TKQ  
Utility.log(sProperty); J1kM\8%b\  

mmsPLv6  
wBzC5T%,  
InputStream input = httpConnection.getInputStream(); 4 :=]<sc,  
//logResponseHead(httpConnection); DlT{`  
|}1dFp  
hph4`{T  
byte[] b = new byte[1024]; h![#;>(  
int nRead; f?b"iA(6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >7r!~+B"9'  
{ ,[Fb[#Qqb  
nStartPos += fileAccessI.write(b,0,nRead); l,:F  
//if(nThreadID == 1) /x
QPTT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t5zKW _J7  
} %S
I'BJ  
4YHY7J  
f)!Z~t &  
Utility.log("Thread " + nThreadID + " is over!");
Fi1@MG5$2  
bDownOver = true; HDKbF/  
//nPos = fileAccessI.write (b,0,nRead); P4?glh q#  
} ddo#P%sH'  
catch(Exception e){e.printStackTrace ();} -N@|QK>  
} 8Y3I0S  
} y]imZ4{/  
:EH=_"  
eFAnFJ][L  
//打印回应的头信息 "j-CZ\]U|  
public void logResponseHead(HttpURLConnection con) r/sNrB1U"y  
{ H-%v3d>
3  
for(int i=1;;i++) q=G+Tocv  
{ G`zm@QL  
String header=con.getHeaderFieldKey(i); .2pK.$.  
if(header!=null) Ah<+y\C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $"&JWT!#  
Utility.log(header+" : "+con.getHeaderField(header)); {)"vN(mX  
else xpI wrJO  
break; P$sxr  
} {T8Kk)L  
} m68*y;#  
zVD:#d%b  
S$k&vc(0  
public void splitterStop() [2koe.?(  
{ b2]Kx&
!  
bStop = true; PX99uWx5]  
} qNr} \J|  
{U1m.30n  
XM}hUJJW  
} l]cFqLp  
to\Ni~a&  
CJ%I51F`X  
/*  9akH  
**FileAccess.java |M_UQQAB|  
*//文件访问(定位，写) 8D].MI^  
package NetFox; bi:8(Q$w:`  
import java.io.*; +)?J#g  
fQ98(+6  
+O5hH8<&b  
public class FileAccessI implements Serializable{ 7Qsgys#/=  
or]IZ2^n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SzRmF1<  
RandomAccessFile oSavedFile; ?q&T$8zc4  
long nPos; GF WA>5n'  
 p#[.{  
{PmZ9  
public FileAccessI() throws IOException aoTP[Bp  
{ tu?MYp;
  
this("",0); tjnIN?YT  
} 80;(Gt@<"  
}`"6aM   
X?$_Sd"G+5  
public FileAccessI(String sName,long nPos) throws IOException Vg23!E  
{ njw|JnDv  
oSavedFile = new RandomAccessFile(sName,"rw"); Tf)*4O4@'  
this.nPos = nPos; fAmz4  
oSavedFile.seek(nPos); Z6p
UZ[j,  
} .~}1+\~5  
'RRE|L,  
 }75e:w[  
public synchronized int write(byte[] b,int nStart,int nLen) =2 kG%9  
{ EE'!|N3  
int n = -1; E"@wek.-  
try{ = f i$}>\  
oSavedFile.write(b,nStart,nLen); Z/K{A`  
n = nLen; sC;+F*0g  
} ?s _
5&j7  
catch(IOException e) L6LZC2N+2  
{ wf$s*|z  
e.printStackTrace (); Dxxm="FQZ  
} $kKjgQS(  
C $JmzrE  
]7mt[2Cd  
return n; N?>vd*  
} `@ FYkH  
jSAjcLR  
0LKRN|@  
} +{UcspqM  
x;')9/3  
qv*^fiT  
/* e]tDy0@  
**SiteInfoBean.java h@h!,;  
*/ >U3cTEs cj  
package NetFox; RGU\h[  
r4f~z$QK  
TU7'J  
public class SiteInfoBean { rt|7h>RQ  
nvUc\7(%NW  
'eX 
'  
private String sSiteURL; //Site's URL F\KUZ[%  
private String sFilePath; //Saved File's Path ,=:D  
private String sFileName; //Saved File's Name /SrAW`;"  
private int nSplitter; //Count of Splited Downloading File J'2X&2  
@]#1(9P  
w-{c.x  
public SiteInfoBean() p"Z-6m~  
{//nSplitter的缺省值为5 eN~=*Mn(za  
//default value of nSplitter is 5 3{h_&Gbo'D  
this("","","",5); !L8#@BjU  
} (b6NX~G-:  
+KEWP\r  
)tpL#J  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) i@BtM9:  
{ U3:j'Su4H?  
sSiteURL= sURL; [=_jYzD,j|  
sFilePath = sPath; 6u}</>}  
sFileName = sName; r)6M!_]AW  
this.nSplitter = nSpiltter; B~du-Z22IZ  
%!L9)(}"  
Ib0ZjX6  
} nJLFfXWx  
KK%M~Y+tU'  
TBrPf-Xr  
public String getSSiteURL() Fr$5RAyg  
{ 2wgg7[tGi  
return sSiteURL; V#}kwON  
} 6Kb1~jY  
jb;hcraR  
r(2uu  
public void setSSiteURL(String value) Lu0x (/  
{ e NafpK  
sSiteURL = value; $DUZ!zaH!  
} 4YX3+oS  
&l[$*<P5V  
&(mR> mT  
public String getSFilePath() -FCe:iY! A  
{ \_6/vZ%-B  
return sFilePath; -7(@1@1  
} [ps*uva  
jMDY(mwt  
<1COZ)  
public void setSFilePath(String value) 9RI-Lq`  
{ HOh!Xcu  
sFilePath = value; CWP2{  
} I15{)o(8$  
c\V7i#u[d;  
)@'}\_a3[]  
public String getSFileName() ]}(H0?OQR  
{ P}G+4Sk  
return sFileName; D{~fDRR  
} U!Z,xx[]  
A$xF$l  
(/*]?Ehd  
public void setSFileName(String value) %-e 82J1  
{ ~**.|%Kc  
sFileName = value; AjgF6[B  
} [=^3n#WW  
aCLqk'  
mju>>
\9  
public int getNSplitter() LRMx<X8  
{ :TC@tM~Oy  
return nSplitter; NL0n009"c$  
} q=qcm`ce  
Mzw X>3x  
H?y,ie#u  
public void setNSplitter(int nCount) *``JamnSO  
{ Q({ r@*g  
nSplitter = nCount; Km6YP!i  
} .Twk {p  
} oD1/{dRzj  
:'&brp3ii=  
3J438M.ka  
/* yD6[\'%  
**Utility.java gy9U2Wgf|  
*/ Wh2tNyS  
package NetFox; v+=BCyT  
3nnJ8zQ  
#3 pb(fbw  
public class Utility { B|AV$N*  
RTJ3qhY  
fCobzDy  
public Utility() eSmLf*\G  
{ fGw9!  
R= o2K  
1"M]3Kl  
} %(G* ,  
v(D;PS3r 7  
//线程睡眠 YNj`W
1  
public static void sleep(int nSecond) {9aE5kR  
{ =;&yd';k  
try{ pK'V9fD5J  
Thread.sleep(nSecond); #7YY<) xt}  
} (%W&4a1di  
catch(Exception e) ^7KH _t8
 
{ g5QZ0Qk
j  
e.printStackTrace (); x&T[*i  
} WoRZW%  
} y(pks$  

"s_lP&nq  
//日志 -JjM y X  
public static void log(String sMsg) `&sH-d4v  
{ E5lBdM>2  
System.err.println(sMsg); /U)D5ot<  
}  *m,k(/>  
_ T):G6C8  
-rli(RR)|  
public static void log(int sMsg) SHo$9+  
{ /&+tf*  
System.err.println(sMsg); ;^I*J:]  
} s '\Uap  
} -f>%+<k=  
 J@Q7p}  
/j|G(vt5  
/* .:QLk&a,:,  
**TestMethod.java aL&7 1^R,  
*/ ,1CIBFY  
package NetFox; !XCm>]R  
xZwLlY  
hUMf"=q+  
public class TestMethod { |! E)GahM  
:'l^kSP_*C  
thM4vq  
public TestMethod() D"?fn<2  
{ ///xx/weblogic60b2_win.exe r^a7MHY1  
try{ 9g"2^^wD  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ssxzC4m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); y6,/:qm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9!}8UALD  
fileFetch.start(); $!yW_HTx  
} 1@1U/ss1  
catch(Exception e){e.printStackTrace ();} ^R Fp8w(  
0dhaAq`k  
usCt#eZK  
} aV|hCN~  
.QJ5sgmh  
YLv'43PL  
public static void main(String[] args) es&vMY  
{ |O9O )o  
new TestMethod(); }h!f eP  
} Midy"  
} /}  WDU  
点击下载更多相关资料