http断点续传简单实现（java)

/*
#%VprcEK  
**SiteFileFetch.java $gDp-7  
*/ X[k-J\  
package NetFox; A(_AOoA'  
import java.io.*; B%6bk.  
import java.net.*; L5T)_iQ5  
^ vI|  
R+]p -NI^  
public class SiteFileFetch extends Thread { %9M; MK  
D{o1G?A  
yP0P-8  
SiteInfoBean siteInfoBean = null; //文件信息Bean iM2 EEC  
long[] nStartPos; //开始位置 fEs957$  
long[] nEndPos; //结束位置 `'Ta=kd3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;t%L(J  
long nFileLength; //文件长度 |PH]0.m5  
boolean bFirst = true; //是否第一次取文件 1hZM))  
boolean bStop = false; //停止标志 y:4Sw#M%(  
File tmpFile; //文件下载的临时信息 ;0E"4(S.q1  
DataOutputStream output; //输出到文件的输出流 j-gLX  
;TSnIC)c  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） CkoPno  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6uDA{[OH  
{ f<SSg*A;  
siteInfoBean = bean; x+B~t4A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); dQM# -t4*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); js
`zQx'  
if(tmpFile.exists ()) JmNeqpbB`w  
{ @usQ*k  
bFirst = false; +azPpGZ=  
read_nPos(); %fP^Fh  
} ~b\7qx_a9  
else JoW*)3Z  
{ p8s2#+/  
nStartPos = new long[bean.getNSplitter()]; O
i BK  
nEndPos = new long[bean.getNSplitter()]; {\|? {8f  
} u-U
UF  
mk\U wv  
i?=3RdP/R1  
{DNc7G  
} SNvK8,"g  
*(?YgV  
O#O~A|  
public void run() #a#~YSnG  
{ "EEE09~l\  
//获得文件长度 b]RCe^E1  
//分割文件 344,mnAd  
//实例FileSplitterFetch j,/o0k,  
//启动FileSplitterFetch线程 D\({]oj]  
//等待子线程返回 >[|:cz  
try{ #*S/Sh?Q  
if(bFirst) 1bzPBi  
{ ;ok];4`a  
nFileLength = getFileSize(); 5B'-&.Aj+  
if(nFileLength == -1) 4L!{U@'  
{ IUd>jHp`6  
System.err.println("File Length is not known!"); ItM?nyA  
} c09]Cp<  
else if(nFileLength == -2) {w!}:8p
 
{ b@YSrjJ  
System.err.println("File is not access!"); N)poe2[  
} ]`m|A1(  
else m.K"IXD  
{ ]?``*{Zqy  
for(int i=0;i<nStartPos.length;i++) l^$:R~gS  
{ @TgCI`E  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }i[i{lKj  
} t ?bq~!X  
for(int i=0;i<nEndPos.length-1;i++) /SMp`Q88  
{ S\0"G*  
nEndPos = nStartPos[i+1]; :\80*[=;Z  
} yrsP'th  
nEndPos[nEndPos.length-1] = nFileLength; }GkEv}~t  
} nWXI*%m5  
} :Hd?0eZ|  
CWBsiL f  
,}{E+e5jh7  
//启动子线程 =Rb,`%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -^#Ix;%  
for(int i=0;i<nStartPos.length;i++) M8juab%y  
{ rcI(6P<*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s ^)W?3t]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), FNc[2sI  
nStartPos,nEndPos,i);  o{-PT'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /c'#+!19  
fileSplitterFetch.start(); }1R k]$XC  
} W!tP sPM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I5x/N.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &7@6Y{!/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2YwV}  
nEndPos = " + nFileLength); 5j]}/Aq  
// fileSplitterFetch[nPos.length-1].start(); K03
a@:  
<S\S @3  
).tZMLM/-  
//等待子线程结束 $oxPmELtpe  
//int count = 0; W:5m8aE\  
//是否结束while循环 =z=Guv
cn`  
boolean breakWhile = false; =HoiQWQs`  
Mm6 (Q  
$u3N',&  
while(!bStop) 4
uNcp0  
{ k ,<L#?,a  
write_nPos(); 0.@/I}R[  
Utility.sleep(500); #h r!7Kc;N  
breakWhile = true; U Ciq'^,  
1]hMA\x  
'|FM|0~-J  
for(int i=0;i<nStartPos.length;i++) c7iu[vE'+  
{ J=\Y4- "  
if(!fileSplitterFetch.bDownOver) E0)v;yRcw  
{ ie$=3nZJ}  
breakWhile = false; ~!:F'}bj  
break; m2_&rjGz  
} ^1Yx'ua'  
} {.!:T+'Xi\  
if(breakWhile) mDM]RAub)  
break; "jeJV,%  
-Q$$2QW!  
5n9F\T5  
//count++; sWX  
//if(count>4) 3}h&/KN{  
// siteStop(); a#raUF7e  
} 8Ae
fgjE  
]AHUo;(f%  
x&9I2"  
System.err.println("文件下载结束！"); <c\aZ9+V  
} B]Zsn`n  
catch(Exception e){e.printStackTrace ();} LG,RF:
 
} e,4!/|H:  
=r_ SMTu  
Xp{gh@#dr  
//获得文件长度 JGO>X|T  
public long getFileSize() $~:hv7%  
{ 4uu*&B  
int nFileLength = -1; wPc,FH+y  
try{ Zy!\=-dSm  
URL url = new URL(siteInfoBean.getSSiteURL()); ~Yr.0i.W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (>8fcQUBb  
httpConnection.setRequestProperty("User-Agent","NetFox"); N@A#e/8  
IsRsjhg8x  
@ym7hk.  
int responseCode=httpConnection.getResponseCode(); Yb?#vp
I  
if(responseCode>=400) o&CvjE  
{ Wc]Fg9E  
processErrorCode(responseCode); ~Snw':  
return -2; //-2 represent access is error qy-B
Z%3  
} `nizGg~1  
mYy3KqYu  
d

->b9  
String sHeader; UWusSi3+LG  
O!j@8~='  
p[/n[@<8=  
for(int i=1;;i++) XBr>K>(  
{ z?gJHN<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Zv-6H*zM6  
//Utility.log(in.readLine()); k,@1rOf  
sHeader=httpConnection.getHeaderFieldKey(i); N9*$'  
if(sHeader!=null) tP:xx2N_  
{ DX!$k[  
if(sHeader.equals("Content-Length")) 6g.@I!j E  
{ )b-G2< kb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >eEf|tKO  
break; FCP5EN  
} A{c6XQR~z  
} |j!D _j#U  
else 4B> l|%  
break; /z'j:~`E
  
} R1wdQ8q  
} MRC5c:(  
catch(IOException e){e.printStackTrace ();} e1IuobT  
catch(Exception e){e.printStackTrace ();} /0\pPc*kA{  
 (&gCVf  
hT Xc0  
Utility.log(nFileLength); ~j4=PT  
6@$[x* V  
' 5Ieqpm9  
return nFileLength; *1%g
=vb  
} {Ise (>V  
zCQv:.0L  
TxiJ?sDh*  
//保存下载信息（文件指针位置） B#gmT2L  
private void write_nPos() es6e-y@e  
{ \GWq0z&  
try{ {otvJ|'N  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L{Th>]X  
output.writeInt(nStartPos.length); /;lk.-yU  
for(int i=0;i<nStartPos.length;i++) JBYQ7SsAS0  
{ 3dM6zOK
  
// output.writeLong(nPos); 2MC\~"
L<  
output.writeLong(fileSplitterFetch.nStartPos); 81n%2G  
output.writeLong(fileSplitterFetch.nEndPos); TcIUo!:z  
} AH} nTm  
output.close();  h43k
 
} Y9%yjh  
catch(IOException e){e.printStackTrace ();} cK258mY  
catch(Exception e){e.printStackTrace ();} NMDNls&)k  
} O]Hg4">f  
Iq5F^rH`[  
U-k;kmaj  
//读取保存的下载信息（文件指针位置） UkYQ<MNO  
private void read_nPos() i3~!ofTb  
{ iIT<{m&`  
try{ "2h#inS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O3_Mrn(R  
int nCount = input.readInt(); !of7]s  
nStartPos = new long[nCount]; jab]!eY  
nEndPos = new long[nCount]; K4rr.f6  
for(int i=0;i<nStartPos.length;i++) t.zSJ|T_&O  
{ z6!
X+`&  
nStartPos = input.readLong(); _I!Xr!!)a0  
nEndPos = input.readLong(); _x \Ll?,  
} &p%,+|  
input.close(); z=xHk|+'  
} h}oQr
0"c  
catch(IOException e){e.printStackTrace ();} 'L m `L<`  
catch(Exception e){e.printStackTrace ();} G'epsD,.bX  
} b'&pJ1]]}  
w Vof_'F1  
[X I5Bu ~  
private void processErrorCode(int nErrorCode) Cse0!7_T  
{ _E%[D(  
System.err.println("Error Code : " + nErrorCode); 2iGRw4`_a  
} p"JSYF 9]  
0g+@WK6y  
UtutdkaS  
//停止文件下载 i~.[iZf|  
public void siteStop() F>M$|Sc2  
{ 5[3hw4  
bStop = true; GWW@8GNI  
for(int i=0;i<nStartPos.length;i++) zZxP= c  
fileSplitterFetch.splitterStop(); T'V(%\w  
]`NbNr]K  
^4[\-L8Lpq  
} NqWHR~&  
} oY]VP+b!  
//负责部分文件的抓取 7Y)wu$!7}  
**FileSplitterFetch.java j\vK`.z  
*/ daorKW4  
package NetFox; . 9 NS  
!69^kIi$  
e%P;Jj476  
import java.io.*; {, |"Rpd  
import java.net.*; `~}7k)F(  
X=hgLK^3<,  
lVFX@I=pI  
public class FileSplitterFetch extends Thread { ^"
Y'zIL  
1Q%.-vs  
y"hM6JI  
String sURL; //File URL MT5A%|He
 
long nStartPos; //File Snippet Start Position I%&9`ceWY  
long nEndPos; //File Snippet End Position xo%iL  
int nThreadID; //Thread's ID PHXP1)^}S  
boolean bDownOver = false; //Downing is over t2:c@)  
boolean bStop = false; //Stop identical <d^7B9O?&w  
FileAccessI fileAccessI = null; //File Access interface yjO7/<2  
~ /[Cgh0  
CvW((<?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +wSm6*j7=  
{ iF0
a  
this.sURL = sURL; hK"=~\,  
this.nStartPos = nStart; @}Ixr{t  
this.nEndPos = nEnd; Lwcw%M]  
nThreadID = id; ;Y'\:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 </Id';|v  
} n96gDH*  
Fs|;>Up0  
YUb,5Y0  
public void run() L,Nr,QC-  
{ z|<oxF.  
while(nStartPos < nEndPos && !bStop) ]Yu+M3Fq  
{ _HK&KY  
8?YW i  
`|w#K28t"  
try{ +m.8*^  
URL url = new URL(sURL); ) T1oDk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *N r|G61  
httpConnection.setRequestProperty("User-Agent","NetFox"); >FHsZKJ  
String sProperty = "bytes="+nStartPos+"-"; -IS9uaT5  
httpConnection.setRequestProperty("RANGE",sProperty); xdM#>z`;  
Utility.log(sProperty); =Q}mJs  
hn|E<  
eh>E).  
InputStream input = httpConnection.getInputStream(); )r i

3ds  
//logResponseHead(httpConnection); E,
fp=.  
nc~d*K\!  
4sQAR6_SW~  
byte[] b = new byte[1024]; @>@Nug2   
int nRead; QL2y,?Mz7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B|=maz:_  
{ X-,y[ )  
nStartPos += fileAccessI.write(b,0,nRead); LwPM7S~ *  
//if(nThreadID == 1) cv4M[]
U~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S7/v,E  
} \,!q[nC  
Q/n.T0Z^  
I 6YT|R  
Utility.log("Thread " + nThreadID + " is over!"); )T5h\ZO`;  
bDownOver = true;  ;"^9L  
//nPos = fileAccessI.write (b,0,nRead); .^S78hr]n  
} F\R}no5C  
catch(Exception e){e.printStackTrace ();} mv?H]i`N  
} y7-:l u$9  
} J\+gd%  
b6Hk20+B;  
<M?#3&5A  
//打印回应的头信息 mtQ{6u  
public void logResponseHead(HttpURLConnection con) $jm<' 4  
{ $-?5Q~  
for(int i=1;;i++) }.cmiC  
{ Oc9>F\]_m  
String header=con.getHeaderFieldKey(i); U_;J.{n  
if(header!=null) Sc$wR{W<:
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8@KFln )[  
Utility.log(header+" : "+con.getHeaderField(header)); SWsv,  
else Mgs|*u-5  
break; V8$bPVps  
} u2BW]T
]  
} ,M&0<k\  
zlztF$Bo  
>Mz|e(6  
public void splitterStop() J<#`IaV  
{ SzlfA%4+GR  
bStop = true; 64']F1p0  
} RhNaYO  
+4g%?5'  
51opP8  
} d 4\E  
Pd "mb~  
d"6]?  
/* tW:/R@@  
**FileAccess.java N8YBu/  
*//文件访问(定位，写) ;u};&sm  
package NetFox; E9B*K2l^{  
import java.io.*; #K1BJ#KUt  
*\:_o5o%[T  
5
%+bWI{w  
public class FileAccessI implements Serializable{ Rfc&OV  
`vxrC&,As  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 kqvJ&7  
RandomAccessFile oSavedFile; P"uHtHK  
long nPos; 8H#c4%by)  
j$8|ym^OX  

hAr[atu87  
public FileAccessI() throws IOException !8@rK$DB  
{ E}' d,v#Z{  
this("",0); n~ >h4=h  
} +F~0\#d  
k?/vy9  
#f3;}1(  
public FileAccessI(String sName,long nPos) throws IOException + lB+|yJ+  
{ )*K<;WIWH  
oSavedFile = new RandomAccessFile(sName,"rw"); EPe]-C`  
this.nPos = nPos; '<&EPUO  
oSavedFile.seek(nPos); -)OkG#J@  
} B.mbKntK)R  
]6BmCh  
*Qg5Z   
public synchronized int write(byte[] b,int nStart,int nLen) ZE8/ 
m")  
{ f;Bfh3  
int n = -1; .eabtGO,  
try{ Q_kT}6#(J=  
oSavedFile.write(b,nStart,nLen); Z0ncN])  
n = nLen; =tc`:!$  
} _:gGD8  
catch(IOException e) S $_Y
/x  
{ <duBwkiG  
e.printStackTrace (); /iTUex7T  
} s"=F^#  
B221}t  
[CDXCV-z  
return n; hX8gV~E=y  
} 1t[;`iZ  
`  -[Bo  
C^,4`OI  
} "37@Zt  
nGv23R(?G  
2z.8rNwT  
/* 6L8tz8  
**SiteInfoBean.java mS:j$$]u  
*/ 5]H))}9>d
 
package NetFox; l$-=Pqb  
xxoHH#a  
f OM^V{)T  
public class SiteInfoBean { "$W|/vD+  
f3zfRhkIk  
c}IX"  
private String sSiteURL; //Site's URL G9i&#)nWr  
private String sFilePath; //Saved File's Path $m:2&lU3  
private String sFileName; //Saved File's Name &Mhv XHI  
private int nSplitter; //Count of Splited Downloading File [ZKtbPHb  
GX7 eRqz>  
d=t}T6.|  
public SiteInfoBean() sb}K%-  
{//nSplitter的缺省值为5 h0F0d^W.  
//default value of nSplitter is 5 t+3   
this("","","",5); >[|GC/
C  
} 8O8\q ;US  
d2C[wQF  
<78$]Z2we  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8! H8[J  
{ stg30><  
sSiteURL= sURL; @V* ju  
sFilePath = sPath; ]pOYVf *$  
sFileName = sName; ?iPZsV  
this.nSplitter = nSpiltter; 5)d,G9  
%\}dbYS '  
,7^d9v3t  
} r,2Xu  
$` Z>Lm*  
S'Z70 zJ  
public String getSSiteURL() dGbU{#"3s  
{ 2^)D .&  
return sSiteURL; =vqsd4  
} KInUe(g<9M  
^&+zA,aL,A  
7
tpAZ<{  
public void setSSiteURL(String value) qri}=du&F  
{ Ws-6W!Ib%  
sSiteURL = value;
@Jb@L  
} Rk($lW)  
bz,Da  
O.@g/05C  
public String getSFilePath() ,wtFs!8  
{ M82.khm~jM  
return sFilePath; 8hTR*e!+  
} <|{L
[  
= n+q_.A  
%`xV'2H  
public void setSFilePath(String value)
K&=1Ap  
{ 6gj]y^}  
sFilePath = value; H$z>OS_6U  
} m b%C}8D  
$|4cJ#;^L  
!oZQ2z~  
public String getSFileName() %04:z77  
{ i{o#3  
return sFileName; y;Qy"-)qb  
} D:=t*2-Iv  
)l`1)Ea~  
't +"k8  
public void setSFileName(String value) 3jvx2  
{ r5t;'eCea  
sFileName = value; EzR%w*F>Q  
} B$cOssl  
{eEBrJJeB  
To3^L_v"
 
public int getNSplitter() M{C6rm|  
{ iI3v[S  
return nSplitter; 2>F
\
&  
} KMUK`tbaI  
fv|]=
e  
QB!jLlg(  
public void setNSplitter(int nCount) `TUZZz  
{ 'S =sj}X  
nSplitter = nCount; C">`' G2  
} 3(1]FKZtt  
} b6 $,Xh  
hS4.3]ei  
dZPW2yf  
/* !n|#|.0m  
**Utility.java EJ1Bq>u7  
*/ 
>BBl7  
package NetFox; Vwjk[ DOL  
ov8 ByJc  
>xT^RYS  
public class Utility { }$l8d/_$[  
e"]"F{Q  
Eu|sWdmf l  
public Utility() Yl$X3wi  
{ ODm&&W#*  
%B@!  
@&;(D!_&  
} Z+ixRch@-s  
vkJ)FEar  
//线程睡眠 M)L/d_4ka  
public static void sleep(int nSecond) 5?Bc Y;  
{ 2z4<N2!M  
try{ fV 3r|Bp  
Thread.sleep(nSecond); .Y;b)]@f  
} yH^f\u0  
catch(Exception e) n
|WfaJQZ  
{ F9-[%l  
e.printStackTrace (); uS~#4;R   
} T=WNBqKo]  
} UH[<&v  
uKv&7p@|_)  
//日志 hi!`9k  
public static void log(String sMsg) qP7G[%=v  
{ WJfES2N  
System.err.println(sMsg); 2UiR~P]%  
} GD!- 
qH  
e9&+vsRmA  
62M
dm3  
public static void log(int sMsg) '_V #;DI  
{ v,{h:  
System.err.println(sMsg); {(4# )K2g%  
} jo}1u_OJ  
} -ey)J +?t  
Z^+rQ.%n"&  
qe?Qeh(!X  
/* +Gow5-(  
**TestMethod.java 
g5i#YW  
*/ []zua14F6  
package NetFox;  A^ViDP  
!siWEzw  
#;]2=
@  
public class TestMethod { _-O cc=Z
 
&iqw! ud  
~O{W;Cyh  
public TestMethod() \6o\+OQk  
{ ///xx/weblogic60b2_win.exe 3+ =I;nj  
try{ mk%b9Ko<F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f8=]oa]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6W&_2a7*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >^=gDJ\a  
fileFetch.start(); JEhm1T  
} ?DPHo)w  
catch(Exception e){e.printStackTrace ();} Z.'syGuV  
w~|1Wd<v  
u`_*g^5q"  
} pISp*&  
$ KB  
,(N[*)G  
public static void main(String[] args) )o{aeV  
{ m2xBS!fm  
new TestMethod(); Ja|{1&J.  
} jZd}OC<  
} n*<v]1  
点击下载更多相关资料