http断点续传简单实现（java)

/* |bjLmGb  
**SiteFileFetch.java jHc/ EZB  
*/ Wu693<  
package NetFox; P)hawH=  
import java.io.*; x_x|D|@wM  
import java.net.*; 9q"G g?  
h>"Z=y  
cP8@'l@!  
public class SiteFileFetch extends Thread { Ijs=4f  
Nv\<>gA:  
@%#!-wC-5  
SiteInfoBean siteInfoBean = null; //文件信息Bean yx/qp<=  
long[] nStartPos; //开始位置 /Pa<I^-#  
long[] nEndPos; //结束位置 90+Hv:wF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Jv:|J DZ'  
long nFileLength; //文件长度 t($z+C<  
boolean bFirst = true; //是否第一次取文件 6bt{j   
boolean bStop = false; //停止标志 9;EY3[N  
File tmpFile; //文件下载的临时信息  SwmX_F#_  
DataOutputStream output; //输出到文件的输出流 A>}]=Ii/  
bqUQadDB  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 0
"=}d y  
public SiteFileFetch(SiteInfoBean bean) throws IOException x`p3I*_HT5  
{ .y~~[QF}8  
siteInfoBean = bean; "RsH
'`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yykyvy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7:&a,nU  
if(tmpFile.exists ()) 8R.`*  
{ JLV?n,nF  
bFirst = false; NKw}VW'|  
read_nPos(); OGU#%5"<  
} lV2MRxI  
else )1]LoEdm`  
{ h3kBNBI )  
nStartPos = new long[bean.getNSplitter()]; =|bW >y  
nEndPos = new long[bean.getNSplitter()]; eR5+1b  
} nB86oQ/S  
1V1T1  
!)'|Y5
o  
69/qH_Y  
} $6\W8v  
Jl,\^)DSw  
]mvVX31T  
public void run() iMOf];O)  
{ TZk.h8  
//获得文件长度 lpeo^Y}N  
//分割文件 >.#tNFAs  
//实例FileSplitterFetch E{6X-C[)v  
//启动FileSplitterFetch线程 =u]FKY  
//等待子线程返回 eFCXjM  
try{ -q/FxESp  
if(bFirst) _yVF+\kQ  
{ +l_$}UN  
nFileLength = getFileSize(); ,
=p.Cx'PR  
if(nFileLength == -1) _fANl}Mf:  
{ eE;")t,  
System.err.println("File Length is not known!"); 'k[gxk|d2  
} f*~z|  
else if(nFileLength == -2) dCM*4B<  
{ F`YxH*tO7  
System.err.println("File is not access!"); Z'z~40Bda  
} S~ 3|  
else )Z2t=&Nw  
{ WP0{%  
for(int i=0;i<nStartPos.length;i++) j\8'P9~%  
{ EM.rO/qcW  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &;k`3`MC~w  
} V/7?]?!xu  
for(int i=0;i<nEndPos.length-1;i++) prg8Iq'w  
{ A)q,VSR8  
nEndPos = nStartPos[i+1]; 4lfJc9J  
} },
LW@Z}  
nEndPos[nEndPos.length-1] = nFileLength; K1>(Fs$  
} Vl+,OBy  
} cZXra(AD  
!4G<&hvb  

)z?Kq0  
//启动子线程 iP~dH/B|v  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 15FGlO<<  
for(int i=0;i<nStartPos.length;i++) 7'xds  
{ ,W/D0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S+YbsLf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~cEr<mzR  
nStartPos,nEndPos,i); mDp|EXN  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z;JZ<vEt92  
fileSplitterFetch.start(); 9#@CmiIhy  
} !Rw\k'<GKX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (&u)FB*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m=<;)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \W6|un  
nEndPos = " + nFileLength); "i_}\p.,X  
// fileSplitterFetch[nPos.length-1].start(); 8h2!8'  
I:aG(8Bi)H  
9jwo f}OU  
//等待子线程结束 H;n(qBSB  
//int count = 0; )(pJ~"'L  
//是否结束while循环 h&6x.ps@  
boolean breakWhile = false; lEC58`Ws  
P&Q 5ZQb  
3It'!R8$  
while(!bStop) 4n@, p0  
{ ZWJFd(6  
write_nPos();  Dk fw*Oo  
Utility.sleep(500); TY|]""3f9  
breakWhile = true; 1xo<V5  
prY9SQd  
]X)EO49  
for(int i=0;i<nStartPos.length;i++) ^$y_~z3o#7  
{ BE}qw
P^  
if(!fileSplitterFetch.bDownOver) lA<IcW  
{ W$B
x?}x($  
breakWhile = false; :8aIj_qds  
break; K9*#H(
  
} .W&rcqy  
} <ZNa`  
if(breakWhile) m H'jr$ ?  
break; STmCj  
+:[dviyPt  
ca_8S8lv  
//count++; UmU=3et<Wj  
//if(count>4) y*6r&989  
// siteStop(); :LFwJ  
} |C S[>0mV!  
<u"#Jw/VP  
yREO
;m|o  
System.err.println("文件下载结束！"); n6nwda  
} c"J(? 1O  
catch(Exception e){e.printStackTrace ();} %;PPu$8K9  
} W3K"5E0ck  
YAZ=-@]`\  
bct&ge7YX  
//获得文件长度 [M2,bc8SJV  
public long getFileSize() <..%@]+  
{ f|FQd3o)  
int nFileLength = -1; _wf
"E(c3D  
try{ 9bXU!l[  
URL url = new URL(siteInfoBean.getSSiteURL()); }~-)31e'`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
\'"q6y  
httpConnection.setRequestProperty("User-Agent","NetFox"); -zz9k=q  
][b
z5aV  
_ #l b\  
int responseCode=httpConnection.getResponseCode(); );;
UNO21+  
if(responseCode>=400) Z-H Kdv!d  
{ u6jJf@!ws  
processErrorCode(responseCode); (s{%XB:K  
return -2; //-2 represent access is error s:cS 9A8  
} 0tB9X9:,  
Zk}e?Grc  
?#D@e5Wf  
String sHeader; Z#;ieI\  
e= "/oo  
a+mq=K  
for(int i=1;;i++) lLtC9:
 
{ ^O\tN\g;c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); aM.l+D
P  
//Utility.log(in.readLine()); foE2rV/Y  
sHeader=httpConnection.getHeaderFieldKey(i); :ykZ7X&  
if(sHeader!=null) i`8!Vm  
{ :eQxdi'  
if(sHeader.equals("Content-Length")) /IV:JVT  
{ x)vYc36H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
{Rw~G&vQ  
break; 8gBqur{  
} +I\bs.84  
} ?67j+)  
else |_[mb(<|  
break; -3_kS/  
} OR"ni  
} [AX).b  
catch(IOException e){e.printStackTrace ();} |klL KX&  
catch(Exception e){e.printStackTrace ();} pdnL~sv  
! 2Y, a  
l/rhA6kEU  
Utility.log(nFileLength);
gYzKUX@  
9fl !CG  
{Y'_QW1:2  
return nFileLength; //Tr=!TQu  
} Bdbw!zRR$  
JBUJc  
N{p2@_fnB  
//保存下载信息（文件指针位置） <O\z`aA'q  
private void write_nPos() FT(EH  
{ *%)L?*  
try{ vlj|[joXw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4?yc/F=kI  
output.writeInt(nStartPos.length); 7 cIVK}&  
for(int i=0;i<nStartPos.length;i++) )s=z i"  
{ tfv]AC7x  
// output.writeLong(nPos); Tu/JhP/g,`  
output.writeLong(fileSplitterFetch.nStartPos); l3iL.?&Pa  
output.writeLong(fileSplitterFetch.nEndPos); [sKdIw_  
} #{ Uk4  
output.close(); z
Lh ~x  
} rX{|]M":T  
catch(IOException e){e.printStackTrace ();} *.nqQhW  
catch(Exception e){e.printStackTrace ();} ^*{xTB57  
} v@t*iDa?7  
3UN Jj&-`  
!&'xkw`  
//读取保存的下载信息（文件指针位置） b$Uwj<v  
private void read_nPos() %W&=]&L  
{ A&t'uY6  
try{ swLgdk{8
n  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [#R%jLEJ2  
int nCount = input.readInt(); :sPku<1is  
nStartPos = new long[nCount]; 8v]{ 5  
nEndPos = new long[nCount]; %74Ms  
for(int i=0;i<nStartPos.length;i++) hU=J^Gi0  
{ Z(}x7jzW  
nStartPos = input.readLong(); x(=kh%\;  
nEndPos = input.readLong(); ap6Vmp  
} fnmZJJ,Q  
input.close(); WX\%FJ  
} )Y *?VqZn  
catch(IOException e){e.printStackTrace ();} n3|~X/I  
catch(Exception e){e.printStackTrace ();} ZXUe4@qfl  
} -I_lCZ{Nbi  

,-b{oS~u  
vy"Lsr3  
private void processErrorCode(int nErrorCode) ;!~;05^iD  
{ dIpt&nH&$  
System.err.println("Error Code : " + nErrorCode); NI^Y%N  
} lMm-K%(2  
yZ!Eu#81  
)$]+R
?v  
//停止文件下载 &J~S $  
public void siteStop() %~W}262  
{ ?&GMp[  
bStop = true; hr{%'DAS  
for(int i=0;i<nStartPos.length;i++) -91l"sI  
fileSplitterFetch.splitterStop(); {X =\  
l.34h  
.e"jnP~  
} Z?X$8o^Z  
} )>Lsj1qk  
//负责部分文件的抓取 x!$,Hcph,  
**FileSplitterFetch.java D1j7iv  
*/ fFd9D=EW.  
package NetFox; j qdI=!H  
Ch.T}%  
"=".ne  
import java.io.*; E%;'3Qykva  
import java.net.*; Asn0&Ys4  
Gqia@>T4*N  
cUm9s>^)/  
public class FileSplitterFetch extends Thread { 7GIv3Dc  
v:HgpZo+  
|v1 K@  
String sURL; //File URL fN4pG*D  
long nStartPos; //File Snippet Start Position G/8xS=  
long nEndPos; //File Snippet End Position ?X9 =4Z~w  
int nThreadID; //Thread's ID 3=<iGX"z  
boolean bDownOver = false; //Downing is over k0YsAa#6V  
boolean bStop = false; //Stop identical f C^l9CRY  
FileAccessI fileAccessI = null; //File Access interface (Dar6>!  
NF1D8uI  
o6y,M!p@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y(]|jRo  
{ dH/t|.%  
this.sURL = sURL; b
 #^aM  
this.nStartPos = nStart; 1`}fbX;"m)  
this.nEndPos = nEnd; EU@mrm?  
nThreadID = id; <zf+Ii1:,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 y="SzPl  
} N*SgP@Bt  
/SUV'J)  
QlS5B.h,  
public void run() x ?V/3zW  
{ 6_y|4!,:W  
while(nStartPos < nEndPos && !bStop) 3'"M31iA  
{ op|mRJBq;  
y[zA[H:  
{4QOUqAu  
try{ <{U{pC
T%  
URL url = new URL(sURL); 7>zKW?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?V{k\1A  
httpConnection.setRequestProperty("User-Agent","NetFox"); kdUGmR0d  
String sProperty = "bytes="+nStartPos+"-"; J
@GfO\ o  
httpConnection.setRequestProperty("RANGE",sProperty); )]%9T
gn  
Utility.log(sProperty);  `JE>GZY  
4'd{H Rs  
#LN I&5  
InputStream input = httpConnection.getInputStream(); NDOZ!`LqH  
//logResponseHead(httpConnection); NI1HUUZz  
E?XCL8NC  
v2n0[b0  
byte[] b = new byte[1024]; jccW8g~ ~  
int nRead; +_gT|vlU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S[a5k;8GL  
{ O|>1~^w  
nStartPos += fileAccessI.write(b,0,nRead); da2[   
//if(nThreadID == 1) ILi5WuOYX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0`!Q-G7  
} |g7h#F~  
i)2))C  
Ft7a\vn*B  
Utility.log("Thread " + nThreadID + " is over!"); N-r
mk  
bDownOver = true; ya{>=  
//nPos = fileAccessI.write (b,0,nRead); Z0=m:h  
} +hg\DqO^M  
catch(Exception e){e.printStackTrace ();} Y/S3)o  
} 2*citB{  
} $CmX &%L=  
vaj66nV  
IPO[J^#Me  
//打印回应的头信息 O8r"M8  
public void logResponseHead(HttpURLConnection con) ^)q2\YE;  
{ (J*w./  
for(int i=1;;i++) UPKi/)C;  
{ 7rSUSra  
String header=con.getHeaderFieldKey(i); (oXN>^-D  
if(header!=null) VWshFI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &{ {DS  
Utility.log(header+" : "+con.getHeaderField(header)); cY2-T#rL  
else %]ay
W$4  
break; ,z1!~gIal  
} ,w%oSlOu  
} z9ShP&^4[  
eUkoVr   
JQ_gM._3  
public void splitterStop() {%_j~  
{ CjQ"oQw  
bStop = true; 5FSv"=  
} , Ln   
Tq84Fn!HJ>  
T'M66kg  
} Q==v!"Gi|  
(L5'rNk  
eFSC^  
/* AD@PNM  
**FileAccess.java u7"Ve
Tz  
*//文件访问(定位，写)
Tj=dL  
package NetFox; _GO+fB/Q1  
import java.io.*; HqdJdWl#"  
{(OIu]:  
cHL]y0>  
public class FileAccessI implements Serializable{ >C3NtGvy  
Y_@"v#,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 A$~x
G(  
RandomAccessFile oSavedFile; =u8D!AxT  
long nPos; fT3*>^Uv  
y5/6nvH_6  
YvruK:I  
public FileAccessI() throws IOException `OP>(bU0  
{ ~g1, !Wl  
this("",0); X
B*}P  
} m*!f%}T  
4C1FPrh  
14D7U/zer  
public FileAccessI(String sName,long nPos) throws IOException *w/WHQ`xI  
{ /u)Rppu  
oSavedFile = new RandomAccessFile(sName,"rw"); :B=8_M  
this.nPos = nPos; NGD*ce"w  
oSavedFile.seek(nPos); Q0cY/'>4  
} x48'1&m  
7B(bH8  
`4%;qLxngP  
public synchronized int write(byte[] b,int nStart,int nLen) 5_)@B]~nM  
{ 3eTrtCe$  
int n = -1; YN@6}B#1  
try{ NLQE"\#a  
oSavedFile.write(b,nStart,nLen); 'e]HP-Y<  
n = nLen; @ EmGexLPM  
} d9Z&qdxTKq  
catch(IOException e) _(6`{PWY  
{ ]G0dS Fh{j  
e.printStackTrace (); '_qQrP#  
} rKzlK 'U  
P>Q{He:  
%l}Q?Z  
return n; 0)AM-/"  
} BF36V\  
HK0::6n{  
vJRnBq+y  
} W7L+8LU;  
4TUtY:  
~o@\ n  
/* :)p)=c8%  
**SiteInfoBean.java JoCA{Fa}  
*/ -|}%~0)/bH  
package NetFox; 0/\PZX+  
't(}Rq@  
'Y!pY]Z  
public class SiteInfoBean { {7?9jEj  
7]|zkjgI  
i3Hz"Qs;  
private String sSiteURL; //Site's URL Sty!atEWT  
private String sFilePath; //Saved File's Path jJ aV  
private String sFileName; //Saved File's Name lwOf)jK:J  
private int nSplitter; //Count of Splited Downloading File s>|Z7[*  
0e+W/Tq  
>5;N64]!)  
public SiteInfoBean() ,?g=U8y|  
{//nSplitter的缺省值为5 sEce{"VC  
//default value of nSplitter is 5 z2w;oM$g  
this("","","",5); 'y9*
uT~  
} \sK:W|yy  
wE$s'e  
U:]MgZWn  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) AkrTfi4hC  
{ Z
XsYn  
sSiteURL= sURL; QsF
4Dl   
sFilePath = sPath; p9-0?(]  
sFileName = sName; M8';%=@  
this.nSplitter = nSpiltter; G#H9g PY  
bD35JG^&i  
74K)aA  
} X JY5@I.  
^qxdmMp)l  
A&?}w_|9  
public String getSSiteURL() x;]x_fz  
{ &%^K,Q"  
return sSiteURL; k-"<{V  
} ]9jZndgC  
__!m*!sd  
Y@Y`gF6F  
public void setSSiteURL(String value) Ic'Q5kfM  
{ XHxz @_rw  
sSiteURL = value; 90~*dN
k  
} -~ 0] 7Cpl  
?g2zmI!U  
{o
dA[H  
public String getSFilePath() }A|))Ao
|  
{ Wo{K}  
return sFilePath; 0G5'Y;8  
} x>%joKY[
 
E0QPE5_  
AD]e0_E  
public void setSFilePath(String value) =3*Jj`AV  
{ |rMq;Rgu?  
sFilePath = value; 1otspOy  
} bM"fk&  
2M
uO*.9D  
XaW4C-D&  
public String getSFileName() bGN 54{f  
{ OX+hZ<y  
return sFileName; 6lsL^]7  
} *>k!hq;
j  
$A`xhh[  
!.EcP=S  
public void setSFileName(String value) f=o4I2Y[  
{ d$K=c1  
sFileName = value; jYWw.g<  
} xO7Yt l  
iK!dr1:wSw  
KmQ^?Ad-C  
public int getNSplitter() LeSHRoD  
{ cZ|lCy^  
return nSplitter; [Ct=F|  
} asr=m{C"  
R2 lXTW*  
|5,<jyp  
public void setNSplitter(int nCount) tMFsA`ng  
{ h4(JUio  
nSplitter = nCount;
.+yW%~0  
} j0FW8!!-g  
} 3B{[%#vO  
?,07;>&  
P16YS8$  
/* )~V}oKk0t  
**Utility.java 5Z{_m;I.  
*/ 4T`&Sl  
package NetFox; }c% pH{HI  
+8AvTSgX%  
*Y%Jl o  
public class Utility { n'K6vW3  
FLZSK:3B]  
J &YQ]l  
public Utility() =g~W%})  
{ +tt9R_S  
;cKH1  
;W{b $k@g  
} MzzKJ;wbC6  
^e%}[q[>|  
//线程睡眠 A
WHU'  
public static void sleep(int nSecond) r`6:Q&&  
{ 5&!'^!  
try{ 8o|P&q(v*  
Thread.sleep(nSecond); ,Ff n)+  
} gn ?YF`  
catch(Exception e) J}TfRrf  
{ y+U83a[L*  
e.printStackTrace (); J8<J8x4  
} y-9+a7j  
} PKf:O  
| o0RP|l  
//日志 Hi7y(h?wj  
public static void log(String sMsg) 81F,Y)x.  
{ dz%EM8  
System.err.println(sMsg); oNM?y:O  
} xWE8Wm  
;YyXT"6/p  
m\vmY  
public static void log(int sMsg) %=Tr^{i  
{ ;..o7I  
System.err.println(sMsg); *Zbuq8>  
} G[Tl
%w  
} cozXb$bBY  
gU1#`r>[)  
,9of(T(~  
/* :243H  
**TestMethod.java ~R]35Cp-#  
*/ P)6lu8zQ  
package NetFox; t6lE#<xZV;  
n~gLPHY  
idc4Cf+4  
public class TestMethod { A\QJLWBv^$  
7:Ztuc]  
 ?=Db@97  
public TestMethod() O#eZ<hNV  
{ ///xx/weblogic60b2_win.exe 9V 0}d2d  
try{ ?
&X6:KJQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H?
`g!cX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k<j"~S1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d]wD[]  
fileFetch.start(); 1n=_y o  
} L":bI&V?:  
catch(Exception e){e.printStackTrace ();} _P7tnXww  

~
i0R^qfr  
/ T c=  
} |/`%3'4H  
,EpH4*e  
A??@AP[7M  
public static void main(String[] args) 6'C2SihYp  
{ Y[ zZw~yx  
new TestMethod(); r&3pM2Da}  
} r"{<%e  
} pyZ9OA!PD  
点击下载更多相关资料