http断点续传简单实现（java)

/* v:E;^$6Vn  
**SiteFileFetch.java L>dkrr)e  
*/ -"=)z/S  
package NetFox; ~W<CE_/]k  
import java.io.*; +b^]Pz5  
import java.net.*; @Mm/C?#*O  
cFK @3a  
*i^`Dw^~y  
public class SiteFileFetch extends Thread { h4_b!E@  
[)^mBVht  
GF8 -_X  
SiteInfoBean siteInfoBean = null; //文件信息Bean sYJL-2JX  
long[] nStartPos; //开始位置 C5|db{=\.*  
long[] nEndPos; //结束位置 #ly@;!M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 OF[?Z  
long nFileLength; //文件长度 &iNwvA%9D  
boolean bFirst = true; //是否第一次取文件 gV8"VZg2  
boolean bStop = false; //停止标志 hoenQ6N^:  
File tmpFile; //文件下载的临时信息 XVt/qb%)r  
DataOutputStream output; //输出到文件的输出流 e+.\pe\  
wd[eJcQ,  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ad9CsvW  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4WC9US-k  
{ C-m*?))go  
siteInfoBean = bean; `5q ;ssu  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yEq#Dr  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *^]~RhjB  
if(tmpFile.exists ()) Tzzq#z&F  
{ Ytao"R/  
bFirst = false; d|XmasGN  
read_nPos(); "xe=N  
} 4U=75!>  
else Z<U>A   
{ F30 ]  
nStartPos = new long[bean.getNSplitter()];  W^Y#pn  
nEndPos = new long[bean.getNSplitter()]; mk!Dozb/  
} lT'9u,6  
T dk ,&8  
5{K}?*3hJ  
*FK`&(B+}  
} ](#&.q%5!  
ib$nc2BPb  
DVlJ*A  
public void run() &fwS{n;U  
{ glE^t6)  
//获得文件长度 er2cQS7R  
//分割文件 x&Cp> +i  
//实例FileSplitterFetch ; Y"N6%
 
//启动FileSplitterFetch线程 N>|XS ,  
//等待子线程返回 =wG+Ao  
try{ <P_ea/5:|  
if(bFirst) ~=En+J}*  
{ bl;zR  
nFileLength = getFileSize();  Ow:1?Z{4  
if(nFileLength == -1) fuUm}N7  
{ @*>Sw>oet  
System.err.println("File Length is not known!"); C$d>_r  
} t{dSX?<nt  
else if(nFileLength == -2) AQss4[\Dx  
{ }fZ`IOf  
System.err.println("File is not access!"); u,1}h L  
} +/rH(Ni  
else #Yuvbb[  
{ geM6G$V&  
for(int i=0;i<nStartPos.length;i++) RO&H5m r%@  
{ ^B/9{0n'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3QXjD/h  
} [q*%U4qGO  
for(int i=0;i<nEndPos.length-1;i++) JWv{=_2w  
{ J~#$J&iKh  
nEndPos = nStartPos[i+1]; >?lOE -}^  
} 52d^K0STC  
nEndPos[nEndPos.length-1] = nFileLength; C[uOReo  
} kW@,$_cK  
} w%y
\dIeI'  
?F7o!B  
k|YWOy@D~  
//启动子线程 yClx` S(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +Qxu$#  
for(int i=0;i<nStartPos.length;i++) 71fk.16  
{ mee$"Y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l|/LQ/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -nbMTY}  
nStartPos,nEndPos,i); 5fJ[}~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4)6xU4eBaL  
fileSplitterFetch.start(); _[K"gu  
} DgHaOAdU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3;[DJ5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A"v
{~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q=uRKh  
nEndPos = " + nFileLength); T?Fcohz(  
// fileSplitterFetch[nPos.length-1].start(); g(C|!}ex/  
|X19fgk  
crcA\lJf  
//等待子线程结束 (u3s"I d  
//int count = 0; "2?l{4T\  
//是否结束while循环 23!;}zHp  
boolean breakWhile = false; o|BP$P8V  
hm*cw[#O1x  
1oLv.L  
while(!bStop) D*P
Yr{z'  
{ O81X;JdP3  
write_nPos(); .7NNT18  
Utility.sleep(500); o Y}]UB>  
breakWhile = true; DZS]AC*  
BYrZEVM9  
:1ecx$  
for(int i=0;i<nStartPos.length;i++) !y:%0{l  
{ @|}BXQNd  
if(!fileSplitterFetch.bDownOver) +|iYg/2  
{ AK!hK>u`  
breakWhile = false; N6OMYP1  
break; /93l74.w  
} wC_l@7t  
} epHJ@W@#  
if(breakWhile) nlYR-.  
break; +!IQj0&'Y3  
@Ky> 9m{  
'*^yAlgtt  
//count++; /iC;%r1L  
//if(count>4) N==ZtKj F  
// siteStop(); /cr}N%HZB  
} Ys+OB*8AE  
H5CR'Rp  
$?G"GQ!.  
System.err.println("文件下载结束！"); g
>rp@M  
} l%ayI  
catch(Exception e){e.printStackTrace ();} $rF=_D6  
} eN?Y7  
LVJI_O{fH  
7hW+T7u?  
//获得文件长度 ._w8J"E5  
public long getFileSize() :<Y}l-x  
{ J_;N:7'p  
int nFileLength = -1; w%AcG~`j!B  
try{ KlV:L 4a~  
URL url = new URL(siteInfoBean.getSSiteURL()); C?
ib_K*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NcOPL\  
httpConnection.setRequestProperty("User-Agent","NetFox"); o%{'UG  
)n49lr6X  
:A %^^F%  
int responseCode=httpConnection.getResponseCode(); 5!YA o\S  
if(responseCode>=400) %CwL:.|  
{ n% 'tKU\q  
processErrorCode(responseCode); Pi,QHb`>  
return -2; //-2 represent access is error A1)wo^,  
} -oeL{9;  
uwf 5!Z:>  
Hs?e0Z=N  
String sHeader; h&.wo !  
{>LIMG-f  
Pg9hW  
for(int i=1;;i++) t^
]$!H  
{ EN{]Qb06A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); XC 7?VE  
//Utility.log(in.readLine()); TD[EQ  
sHeader=httpConnection.getHeaderFieldKey(i); YjF|XPv+ l  
if(sHeader!=null) ^,l_{  
{ ?Xdak|?i  
if(sHeader.equals("Content-Length")) 9Zry]$0~R
 
{ NN0$}acp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Uoya3#4 G  
break; [ EFMu;q  
} Djk C  
} Uz cx6sw  
else 2%*MW"Q  
break; {oc igR0  
} E$9Y
s  
} t?o,RN:  
catch(IOException e){e.printStackTrace ();} b|Q)[y]  
catch(Exception e){e.printStackTrace ();} 5D M"0  
-9RDr\&`(  
MMB@.W  
Utility.log(nFileLength); mk7&<M  
O#wpbrJ  
,B4VT 96*  
return nFileLength; {3})=>u:S  
} *k"|i*{  
X[#zCM  
M8H5K  
//保存下载信息（文件指针位置） ^7;JC7qmN  
private void write_nPos() P%)gO  
{ 5@*'2rO&!  
try{ Hf'G8vW  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D7Y)?Z5A;  
output.writeInt(nStartPos.length); .@ xF6UZ  
for(int i=0;i<nStartPos.length;i++) x^Yl*iq  
{ gtUUsQ%y.  
// output.writeLong(nPos); i)#:qAtP*  
output.writeLong(fileSplitterFetch.nStartPos); m}>F<;hQ  
output.writeLong(fileSplitterFetch.nEndPos); k = ?h~n0M  
} 1qV@qz  
output.close(); A:(*y 2  
} =%
'`YbD$  
catch(IOException e){e.printStackTrace ();} Zm
OfEg|h\  
catch(Exception e){e.printStackTrace ();} D\<y)kh  
} 8/)qTUx:  
Oj<S.fi  
["\;kJ.  
//读取保存的下载信息（文件指针位置） +,~zWv1v  
private void read_nPos() 0]D0{6x8  
{ 8|E'>+ D_-  
try{ JS}{%(B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); XLMb=T~S  
int nCount = input.readInt(); *'ZB*>  
nStartPos = new long[nCount]; >~`C-K#  
nEndPos = new long[nCount]; s@MYc@k  
for(int i=0;i<nStartPos.length;i++) ==i[w|  
{ XqM3<~$  
nStartPos = input.readLong(); cYXM__  
nEndPos = input.readLong(); /1?R?N2>0  
} @HZKc\1  
input.close(); cRX~z  
} lL]y~u  
catch(IOException e){e.printStackTrace ();} 4&/j|9=X  
catch(Exception e){e.printStackTrace ();} L[5=h  
} d #jK=:eK  
Z|RY2P>E  
Xf)|Pu  
private void processErrorCode(int nErrorCode) iH^z:%dP  
{ -,K!  
System.err.println("Error Code : " + nErrorCode); q80S[au  
} ]*7Y~dO  
-W,}rcj*|  
(C]o,7cYS  
//停止文件下载 6_N(;6kx(  
public void siteStop() 1-RIN}CSd  
{ wP"dZagpj  
bStop = true; Qr Wj>uR  
for(int i=0;i<nStartPos.length;i++) K't]n{$  
fileSplitterFetch.splitterStop(); bQ|V!mrN}  
1s1=rZ!  
%e*@CbO$  
} 5SkW-+$  
} 5>AX*]c  
//负责部分文件的抓取 T{wuj[Q#:  
**FileSplitterFetch.java \M'-O YH_[  
*/ )Ud-}* g  
package NetFox; L@JOGCYy  
h*ZC*eV>  
#07gd#j4  
import java.io.*; :!zl^J;  
import java.net.*; &@ JvnO:  
d GP*O  
RCRpzY+@  
public class FileSplitterFetch extends Thread { tH'2
g
l   
YJ(*wByM  
tpuYiL  
String sURL; //File URL @29U@T  
long nStartPos; //File Snippet Start Position |d6T/Uxo  
long nEndPos; //File Snippet End Position :_M;E"9R  
int nThreadID; //Thread's ID d;n."+=[x  
boolean bDownOver = false; //Downing is over a~8[<Fomj  
boolean bStop = false; //Stop identical wgd/(8d  
FileAccessI fileAccessI = null; //File Access interface Nan
[<  
!'L
W_@  
{nU=%w"\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {}:ToIp  
{ $['Bv  
this.sURL = sURL; <T[E=#  
this.nStartPos = nStart; F[
ewn/]n  
this.nEndPos = nEnd; NWxUn.Gy9  
nThreadID = id; FZ8b7nJ)4m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Y2'cs~~$Ce  
} ]~Y<o  
T6ENtp  
)?wJF<[_#  
public void run() ?k(\ApVHj  
{ ws^4?O  
while(nStartPos < nEndPos && !bStop) sUE?v9  
{ @?"h !fyu  
KN-avu_Ix  
mS0udHod  
try{ vOg#Dqn-  
URL url = new URL(sURL); ,]T2$?|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'w1YFdW  
httpConnection.setRequestProperty("User-Agent","NetFox"); E@Ad'_H  
String sProperty = "bytes="+nStartPos+"-"; .KdyJ
6o  
httpConnection.setRequestProperty("RANGE",sProperty); s=[h?kB  
Utility.log(sProperty); ,!U=|c"k)  
&IlU|4`R%  
`Qeg   
InputStream input = httpConnection.getInputStream(); =N 5z@;!  
//logResponseHead(httpConnection); 1!>Jpi0  
*-
xU2  
@O[5M2|r  
byte[] b = new byte[1024]; N]RZbzK_5G  
int nRead; =Fdg/X1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
@Vu(XG  
{ ~H!S,"n^,P  
nStartPos += fileAccessI.write(b,0,nRead); "+unS)M;Y  
//if(nThreadID == 1)
N<DGw?Rl  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \(%Y%?dy  
} '? jlH0;  
)XWP\ h  
|.wEm;Bz  
Utility.log("Thread " + nThreadID + " is over!"); B2ec@]uD`  
bDownOver = true; 36am-G  
//nPos = fileAccessI.write (b,0,nRead); MeUaTJFEB  
} ?mlNL/:  
catch(Exception e){e.printStackTrace ();} h>Hb`G<  
} -1J[n0O.  
} +T8B:  
uw2hMt (N  
D.mHIsX6\  
//打印回应的头信息 /JT#^Y  
public void logResponseHead(HttpURLConnection con) a.z;t8  
{ /q5:p`4{J  
for(int i=1;;i++) gJM`[x`T  
{ Y/7 $1
k  
String header=con.getHeaderFieldKey(i); <mAhr  
if(header!=null) !fj(tPq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ZI=v.wa  
Utility.log(header+" : "+con.getHeaderField(header)); <ZB1Vi9}8  
else -I=l8m6L  
break; !>1@HH?I\/  
} E4hLtc^ +
 
} y{N-+10z
 
q&d~ \{J  
6&/T@LQYrh  
public void splitterStop() R
Z+`T+zL  
{ p QizJ6  
bStop = true; __.+s32SS$  
} 4^URX>nx8  
QVtQx>K`  
9V5-
%Iv  
} ooQQ-?"m  
NC38fiH_N  
7.`fJf?   
/* db6mfxi  
**FileAccess.java 1/"WD?a  
*//文件访问(定位，写) rdJR 2  
package NetFox; s-v  
import java.io.*; &?(?vDFfZ  
y99mC$"Ee`  
LGtIm7  
public class FileAccessI implements Serializable{ Hhh0T>gi  
KRA/MQ^7~U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _F`lq_C  
RandomAccessFile oSavedFile; /bVoErf  
long nPos; XcjRO#s\  
4#lo$#  
9yfJVg  
public FileAccessI() throws IOException &#iTQD  
{ B $mX3B
+a  
this("",0); K1T4cUo  
} O<V4HUW  
^(FdXGs[  
v;ZA4c  
public FileAccessI(String sName,long nPos) throws IOException rh^mJUh  
{ |)*fRL,  
oSavedFile = new RandomAccessFile(sName,"rw"); q*9!,!e  
this.nPos = nPos; aca=yDs2  
oSavedFile.seek(nPos); &Udb9  
} a0#J9O_  
(I./ Uu%  
}1upi=+aE  
public synchronized int write(byte[] b,int nStart,int nLen) 1aTB%F  
{ :*KHx|Q  
int n = -1; L'kmNVvYN  
try{ P ! _rEV  
oSavedFile.write(b,nStart,nLen); ;&)-;l7M  
n = nLen; WILMH`  
} >=-(UA  
catch(IOException e) hr
)B[<9  
{ aYSCw3C<  
e.printStackTrace (); t)}scf&^x  
} ;-qO'V:;  
@qYp>|AF  
[;J>bi;3N  
return n; @
 rc{SB  
} %B.yW`,X  
%xyou:~0zs  
K9up:.{QQ  
} Qr{E[6  
k-^mIJo}  
5f 5f0|ok  
/* :w^Ed%>y7  
**SiteInfoBean.java #e$5d>j(  
*/ h[@tZ(jrY  
package NetFox; 73\JwOn~  
&eX!#nQ_.  
|Ur"& Z{  
public class SiteInfoBean { {fjdr  
XY3v_5~/1F  
Z
NvEW  
private String sSiteURL; //Site's URL u@cYw:-C  
private String sFilePath; //Saved File's Path #*UN
>X  
private String sFileName; //Saved File's Name $[a8$VY^Cm  
private int nSplitter; //Count of Splited Downloading File 0a XPPnuX  
]Yn_}Bq  
SR|`!  
public SiteInfoBean() @/ohg0  
{//nSplitter的缺省值为5 P&^;656r  
//default value of nSplitter is 5 z\%67C  
this("","","",5); B e0ND2oo  
} _dhgAx-H)h  
#;2n;.a  
8p:e##%  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) CmoE_8U>  
{ v: OR   
sSiteURL= sURL; /^#;d UB  
sFilePath = sPath; {C N~S*m  
sFileName = sName; 4?q
<e*W  
this.nSplitter = nSpiltter; :x4|X8>  
wMg0>  
!`Hd-&}bYz  
} fy@<&U5rg  
%2{%Obp'  
|#cm`v  
public String getSSiteURL() =V-|#j  
{ TI,&!E?;  
return sSiteURL; FwkuC09tI  
} HOJs[m
qB%  
`3WFjU5a  
P"8~$ P#  
public void setSSiteURL(String value) kr9*,E9cv  
{ %|q>pin2  
sSiteURL = value; sl`s_$J  
} mQ|v26R  
%1xb,g KO  
(jRm[7H  
public String getSFilePath() ?En O"T.  
{ :fZ}o|t7  
return sFilePath; QLiu2U o  
} 8y.wSu  
gf &Pn  
B][U4WJ)  
public void setSFilePath(String value) #(N+(():  
{ D"2&P^-  
sFilePath = value; BMG3|N^  
} xg;+<iW  
YSic-6z0Ms  
lJ}_G>GJ  
public String getSFileName() DpvI[r//'*  
{ L(|N[#  
return sFileName; 1q:2\d]  
} jZ~n[ f+Q  
2q=AEv/  
PGhY>$q>b  
public void setSFileName(String value) bB1UZ O  
{ Vr`R>S,-
 
sFileName = value; NflD/q/ L  
} \F/hMXDlJ  
x7!L{(E3  
%\dz m-d(C  
public int getNSplitter() <66X Xh.  
{ 7e|s wJ>4  
return nSplitter; 0zl
b0[  
} |@ s,XS  
C.Kh[V\Ut  
i]YV {  
public void setNSplitter(int nCount) %,}A@H,  
{ 8QLj["   
nSplitter = nCount; pz\ +U7  
}
IoQEtA  
} z<U-#k7nz  
ORHp$Un~)  
?mFv0_!O
 
/* "4+&-ms  
**Utility.java "/3'XOK|  
*/ @s ?  
package NetFox; l1OE!W W  
P2BWuhF  
bnq;)>&  
public class Utility { )NXmn95  
K/j3a[.  
A@1W}8qY:  
public Utility() bLij7K2H  
{ 7Bzq,2s
 
pfA|I*`XV  
v&Yi  
} Ai=se2  
Pq;U&,  
//线程睡眠 )wam8k5  
public static void sleep(int nSecond) &:9cAIe]H  
{ =.f-w0V  
try{ ;c-(ObSm  
Thread.sleep(nSecond); K6v6ynp/  
} &C,'x4c"  
catch(Exception e) 7~^GA.92  
{ oTU!R ,  
e.printStackTrace (); jnKWZ/R  
} y&q*maa[  
} Fq~yL!#!  
,Ys %:>?  
//日志 ZRh~`yy  
public static void log(String sMsg) 5[k/s}g  
{ 8=B|C'>  
System.err.println(sMsg); M -cTRd-i  
} `w#Oih!6A|  
v5!d$Vctu  
2&:f&"  
public static void log(int sMsg) h)ECf?r<  
{ WejYy|  
System.err.println(sMsg); w28o}$b`  
} @=bLDTx;c)  
} Q('r<v96  
]qethaNy  
&S{RGXj_  
/* xu/cq9  
**TestMethod.java 1an^1!  
*/ T! Y@`Ox  
package NetFox; R} eN@#"D  
kO.%9wFbz  
=x%dNf$e{W  
public class TestMethod { 2h|MXI\g  
gp};D  
8;b(0^  
public TestMethod() m,*QP*  
{ ///xx/weblogic60b2_win.exe 8'r2D+Vwm  
try{ }iXDa?6%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3
KRd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <r.)hT"0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6}gls}[0{e  
fileFetch.start(); 1L%CJ+Q#0i  
} 8##-EN;ag  
catch(Exception e){e.printStackTrace ();} 0Is,*Srr  
a]JYDq`,3  
BWeA@v  
} [pC$+NX  
3c#BKHNC
 
%+@O#P  
public static void main(String[] args) ypbe!Y<i]  
{ m!|kW{B#A  
new TestMethod(); 5L+>ewl  
} oRm L {UDZ  
} 0LPig[  
点击下载更多相关资料