http断点续传简单实现（java)

/* VH7iH|eW  
**SiteFileFetch.java ?9('o\N:  
*/ /K1$_  
package NetFox; l9ifUhe  
import java.io.*; ,syA()  
import java.net.*; :d% -,v  
F;MT4*4  
$Va]vC8?  
public class SiteFileFetch extends Thread { }lNufu  
1)/T.q<D"  
ktw!T{  
SiteInfoBean siteInfoBean = null; //文件信息Bean tZNad  
long[] nStartPos; //开始位置 wWOT*R_  
long[] nEndPos; //结束位置 zW"3K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 LG&Q>pt.  
long nFileLength; //文件长度 '#4mDz~  
boolean bFirst = true; //是否第一次取文件 d'AviW>  
boolean bStop = false; //停止标志 E9Xk8w'+  
File tmpFile; //文件下载的临时信息 5cNzG4z  
DataOutputStream output; //输出到文件的输出流 (;2J(GZ:$U  
{ck  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :LIKp;  
public SiteFileFetch(SiteInfoBean bean) throws IOException l6`d48U
 
{ L"[wa.<  
siteInfoBean = bean; SbPjU50  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Z'EO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); IjB*myN.  
if(tmpFile.exists ()) Z;~E+dXC  
{ >h!.Gj  
bFirst = false; |Z7bd^  
read_nPos(); tls6rto  
} 0ZID @^  
else XM@-Y&c$A  
{ bF Y)o Z  
nStartPos = new long[bean.getNSplitter()]; kkE)zF   
nEndPos = new long[bean.getNSplitter()]; $NGtxZp  
} <0Egkz3s  
aji~brq  
Acq>M^E3  
^0ZKHR(}e  
} cdtzf:#q  
ZvnZ}t>?  

1M~:]}*<  
public void run() %`\3V {2*  
{ /"
%IhX-  
//获得文件长度 PcSoG\-G<  
//分割文件 J|2Hqd  
//实例FileSplitterFetch U*R~w5W.[  
//启动FileSplitterFetch线程 +} !F(c  
//等待子线程返回 z7Rcnr;  
try{ G4exk5  
if(bFirst) Znl>*e/|  
{ XFf+efh  
nFileLength = getFileSize();  0[!gk]p  
if(nFileLength == -1) In9|n^=H@  
{ jVFRqT%  
System.err.println("File Length is not known!"); tCCi|*P G  
} U9p.Dh~)vG  
else if(nFileLength == -2) KGE-RK  
{ -TU{r_!Z(  
System.err.println("File is not access!"); Q0"F>%Cn  
} fddbXs0Sn  
else V
F!kr1n!  
{ zRJKIm  
for(int i=0;i<nStartPos.length;i++) O->(9k<  
{ xc]C#q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $:gSc&mx  
} FiU;>t<)  
for(int i=0;i<nEndPos.length-1;i++) ~ %YTJS  
{ iJKm27 ">  
nEndPos = nStartPos[i+1]; io?{ew  
} ~lalc ^  
nEndPos[nEndPos.length-1] = nFileLength; 8.%a"sxr  
} cA*X$j6  
} ]Y: W[p  
I'%H:53^0  
rPGE-d3  
//启动子线程 <:;:*s3]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; twHM~cTS  
for(int i=0;i<nStartPos.length;i++) L+ETMk0  
{ gZ>orZL'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pQMpkAX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xEZVsz  
nStartPos,nEndPos,i); @61N[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _BLSI8!N@  
fileSplitterFetch.start(); ;YXr
G  
} {6y.%ysU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [[r3fEr$!p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); p$o&dQ=n[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", JHh9> .1  
nEndPos = " + nFileLength); dj&m  
// fileSplitterFetch[nPos.length-1].start(); D*r Zaqy  
rB&j"p}Q  
dpn&)?f  
//等待子线程结束 @?cXa: tX  
//int count = 0; <<zz*;RJJ  
//是否结束while循环 6M vRR  
boolean breakWhile = false; "`gZy)E  
*0@; kD=  
i~s9Ot  
while(!bStop) mhkAI@)>  
{ +xdFkc  
write_nPos(); q
jEWk."  
Utility.sleep(500); 2l/5i]Tq  
breakWhile = true; +?txGHQq  
C\>Mt  
@P5@&G  
for(int i=0;i<nStartPos.length;i++) VJtTbt;>  
{ f5qHBQ  
if(!fileSplitterFetch.bDownOver) D&6Qk&>  
{ Eno2<<  
breakWhile = false; CU^3L|f2N  
break; I4X+'fW,  
} G@<lwnvD*J  
} n6UU6t{  
if(breakWhile) uZ?CVluP  
break; 70*iJ^|  
U <$xp  
Wu;|(2I  
//count++; KY34 'Di  
//if(count>4) 7{6.  
// siteStop(); Y{|~A  
} -j=&J8Za  
=2)$|KC  
/(pD^D  
System.err.println("文件下载结束！"); z,x"vK(  
} i|{nj\6w^  
catch(Exception e){e.printStackTrace ();} 0uJzff!|  
} TvG:T{jwy  
gsm^{jB  
D
!$ =oK  
//获得文件长度 Vyq<T(5  
public long getFileSize() >A( C9_\  
{ glX2L~  
int nFileLength = -1; ;Y&?ixx  
try{ V42*4hskL  
URL url = new URL(siteInfoBean.getSSiteURL());
3$yL+%i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8]MzOGB8  
httpConnection.setRequestProperty("User-Agent","NetFox"); NITx;iC  
H;Qn?^  
uW'4 Kt  
int responseCode=httpConnection.getResponseCode(); QuRg(K%:  
if(responseCode>=400) ~dr1Qi#j?  
{ GfPz^F=ie.  
processErrorCode(responseCode); :#htOsP  
return -2; //-2 represent access is error Qr-J-2s?B  
} i[^lJ)[>N  
=&/a\z!  
5Zm_^IS  
String sHeader; ~teW1lMu(  
A.x}%v,E  
v]SE?xF{U  
for(int i=1;;i++) Y"rV[oe  
{ "t&k{\$\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 17]
31  
//Utility.log(in.readLine()); qFChZ+3>  
sHeader=httpConnection.getHeaderFieldKey(i); +Qvgpx>  
if(sHeader!=null) &b")`p&K  
{ @,`=~_J  
if(sHeader.equals("Content-Length")) :k/U7 2  
{ {u6fa>R&$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6|qvo+%  
break; `e=n(D  
} ^&/&I9z  
} 9<c4y4#y  
else `v2l1CQ:^  
break; pyJOEL]1F  
} `+;oo
B  
} _rVX_   
catch(IOException e){e.printStackTrace ();} < LAD  
catch(Exception e){e.printStackTrace ();} q&6=oss!  
&B0&183  
oYErG],  
Utility.log(nFileLength); OmbKx&>YGz  
"$cT*}br  
5GL+j%7  
return nFileLength; mg/kyua^  
} !:[n3.vm  
QF "&~
 
#LgoKiP!Y  
//保存下载信息（文件指针位置） cP=mJ1  
private void write_nPos() +p6\R;_E  
{ hdqls0 r  
try{ @W- f{V  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /l%qq*Ew  
output.writeInt(nStartPos.length); 'c{]#E1}  
for(int i=0;i<nStartPos.length;i++) &U)s%D8e;d  
{ nKkTnTSa  
// output.writeLong(nPos); ZM, ^R?e  
output.writeLong(fileSplitterFetch.nStartPos); Cbvl( (  
output.writeLong(fileSplitterFetch.nEndPos); A0u:Fm{E  
} w=o m7%J@l  
output.close(); -\C6j  
} [IA==B7  
catch(IOException e){e.printStackTrace ();} :Fp
Bz~!a  
catch(Exception e){e.printStackTrace ();} L([>yQZ  
} gt(nZ
  
A8(PI)Ic.  
V46[whL%r  
//读取保存的下载信息（文件指针位置） !sQ8,l0h  
private void read_nPos() EZRZ)h  
{ K -1~K  
try{ \ySc uT  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); n(S-F g  
int nCount = input.readInt(); d'fpaLV  
nStartPos = new long[nCount]; Q9zpX{JT  
nEndPos = new long[nCount]; K#< Wt5  
for(int i=0;i<nStartPos.length;i++) H,` XCG  
{ ^V]DY!@k3_  
nStartPos = input.readLong(); tah%jRfT&  
nEndPos = input.readLong(); 6dp_R2zH~o  
} I;:_25WGC  
input.close(); gdNp2b  
} j&GK
pt  
catch(IOException e){e.printStackTrace ();} K):sq{  
catch(Exception e){e.printStackTrace ();} bl-s0Ax-  
} jk}PucV  
GFkte  
|T&#"q,i9%  
private void processErrorCode(int nErrorCode) Lb 4!N`l  
{ .tsB$,/  
System.err.println("Error Code : " + nErrorCode); cs;Gk:  
} g``4U3T%X  
u Aa>6R  
jhM|gV&  
//停止文件下载 $Ws2g*i  
public void siteStop() Y2&6xTh  
{ ITUl-L4xE  
bStop = true; 7gaC)j&  
for(int i=0;i<nStartPos.length;i++) .e#j#tQp  
fileSplitterFetch.splitterStop(); ?7a[|-  
!,uw./8@Ku  
.6#2i <oPW  
} M4\Io]}-M  
} Zotv]P2k  
//负责部分文件的抓取 wuQkeWxJ  
**FileSplitterFetch.java YWFHiB7x
 
*/ f+AIxSw  
package NetFox; `"Pd$jW  
2Jv4l$$;*  
SX;IUvVE5  
import java.io.*; 1bs95Fh9Q  
import java.net.*; iO`f{?b  
Lr
&BZM  
-;z\BW5y  
public class FileSplitterFetch extends Thread { vdzC2T  
T/5UlW|\  
{v(|_j&:o  
String sURL; //File URL kICYPy  
long nStartPos; //File Snippet Start Position WfZ#:G9  
long nEndPos; //File Snippet End Position 5UyK
1e))  
int nThreadID; //Thread's ID xG
L"N1  
boolean bDownOver = false; //Downing is over t$iU|^'uV  
boolean bStop = false; //Stop identical D40VJ3TUc  
FileAccessI fileAccessI = null; //File Access interface gk%ye&:f  
P'k39  
Wfy+7$14M  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException iJeT+}  
{ }c
lNXtN  
this.sURL = sURL; ~VF,qspO  
this.nStartPos = nStart; wE2?/wb  
this.nEndPos = nEnd; ,fFJSY^  
nThreadID = id; $hh=-#J8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -+/|  
} $=R\3:j  
`#F>?g$2  
uES
HTX/[  
public void run() n1h+`nsf  
{ |lY8u~%  
while(nStartPos < nEndPos && !bStop) -tZb\4kh  
{ K)ib{V(50  
#*@Yil=1  
uRg^:  
try{ nr;/:[F  
URL url = new URL(sURL); 8nM]G4H.f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?'r[P03  
httpConnection.setRequestProperty("User-Agent","NetFox"); u5[Wr:  
String sProperty = "bytes="+nStartPos+"-"; ERplDSfO-  
httpConnection.setRequestProperty("RANGE",sProperty); %+}\i'j7  
Utility.log(sProperty); )DMbO"7  
3{z }[@N  
><HXd+- sd  
InputStream input = httpConnection.getInputStream(); _qfdk@@g  
//logResponseHead(httpConnection); =6:Iv"<  
H]\H'r"  
LBR_Q0EP  
byte[] b = new byte[1024]; ;$]R#1i44  
int nRead; WxdYvmp6z[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a*`J]{3G  
{ 5Jp>2d  
nStartPos += fileAccessI.write(b,0,nRead); M Cz3RZK  
//if(nThreadID == 1) oT w1w  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O"GzeEY7  
} 8~7EWl  
'yqp  
Lm/^ 8V+  
Utility.log("Thread " + nThreadID + " is over!"); ~ nIZg5  
bDownOver = true; ezeGw?/  
//nPos = fileAccessI.write (b,0,nRead); '1aOdEZA*  
} pQD8#y)`C  
catch(Exception e){e.printStackTrace ();} WD]dt!V%  
} JaEyVe  
} &Jz%L^  
Q_S fFsY  
NH/H+7,o  
//打印回应的头信息 Ghz)=3  
public void logResponseHead(HttpURLConnection con) @EvnV.  
{ h fNBWN  
for(int i=1;;i++) -.y3:^){^  
{ v{+*/NQ_  
String header=con.getHeaderFieldKey(i); +%^D)   
if(header!=null) [z?XVl<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4Q.70  
Utility.log(header+" : "+con.getHeaderField(header)); O<5bsKw'r  
else "[G P)nC  
break; V.}U p+WL  
} M II]sF  
} zKZ6Qjd8!  
s_|wvOW)'  
4YJs4CB  
public void splitterStop() ^H>vJT  
{ {k>m5L  
bStop = true; ;X>KP,/r$  
} /D~:Ufw  
Ty5\zxC|  
i^(0,L  
} XyhdsH5%3!  
wTLHg2'y^  
rYT3oqpfT  
/* t}K?.To$  
**FileAccess.java ;tj_vmZ@R  
*//文件访问(定位，写) "dt3peH  
package NetFox; PGJ?=qXr#  
import java.io.*; cCwT0O#d  
$W)FpN;CW/  
^#%[  
public class FileAccessI implements Serializable{ +r '  
6sntwT"?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )g-*fSa  
RandomAccessFile oSavedFile; |h;MA,qva  
long nPos; 7G xNI  
E+_}8J .  
"8N]1q:$4  
public FileAccessI() throws IOException -?ip?[Z  
{ y
RAb HG,c  
this("",0); {3?g8e]zr  
} YEGXhn5E  
BZE19!  
mu(S9  
public FileAccessI(String sName,long nPos) throws IOException ?/O+5rjA  
{ /OZF3Pft  
oSavedFile = new RandomAccessFile(sName,"rw"); $0WAhq  
this.nPos = nPos; s%Z3Zj(,8(  
oSavedFile.seek(nPos); _A(J^;?  
} ,ihTEw,t(  
btee;3`  
4&?%"2  
public synchronized int write(byte[] b,int nStart,int nLen) ?qdG)jo=  
{ H|Eu,eq-E  
int n = -1; ,5nrovv  
try{ h><;TAp  
oSavedFile.write(b,nStart,nLen); '&\km~&  
n = nLen; -.xs=NwB.|  
} Lz4iLLP  
catch(IOException e) R+5x:mpHy  
{  ]3%Z  
e.printStackTrace (); J,k{Bm  
} 1w35H9\g  
E*[X\70  
WL>"hkx  
return n; Yx,  
} P /Js!e<\  
[z?q-$#  
D:f0Wv  
} {&3n{XrF(  
hD;[}8qN{  
|d8/ZD  
/* 2/I^:*e  
**SiteInfoBean.java CFVe0!\  
*/ &a O
3N  
package NetFox; #[2]B8NZ  
<pz;G}  
$U<xrN>O  
public class SiteInfoBean { /QG8\wXE2  
Mk7#qiPo  
m(?M]CH(A  
private String sSiteURL; //Site's URL A|jaWZM-  
private String sFilePath; //Saved File's Path .' #_Z.zr  
private String sFileName; //Saved File's Name ^oj)#(3C  
private int nSplitter; //Count of Splited Downloading File =6/0=a[  
r..\(r  
0,,x|g$TpT  
public SiteInfoBean() C:W}hA!  
{//nSplitter的缺省值为5 2rne=L  
//default value of nSplitter is 5 m7fmQUk  
this("","","",5); ze]2-
B4  
} 7kHEY5s "  
B;L~hM  
Uq7 y4zJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) + 6O5hZ  
{ 'a*tee ^RS  
sSiteURL= sURL; [CJ&Yz Ji  
sFilePath = sPath; 0IxXhu6v  
sFileName = sName; @2]_jW  
this.nSplitter = nSpiltter; JhIgqW2  
S's\M5  
[|e7oNT(Q  
} {p+7Q
lgK  
1)vdM(y3j  
wS#.Wzp.w  
public String getSSiteURL() *s<FEF  
{ On#RYy^}  
return sSiteURL; N^B YNqr  
} na_Y<R`  
&ciU`//`  
]k5l]JB  
public void setSSiteURL(String value) $#1i@dI  
{ <S%M*j  
sSiteURL = value; -Y{P"!p0  
} <Jv %}r  
ZEp UHdin  
,ie84o  
public String getSFilePath() 7i,}F|#8  
{ \2@OS6LUe  
return sFilePath; IZoa7S&t  
} \5cAOBja  
nxw]B"Eg  
`A])4q$  
public void setSFilePath(String value) j!xt&t4D  
{ 1 f).J  
sFilePath = value; /X{:~*.z  
} 6MqJy6  
C|8.$s<  
J[du
>1D  
public String getSFileName() Ns?y) G>:  
{ H"6Sj-<=  
return sFileName; /w$<0hH#'8  
} ]G#og)z4  
.|;`qUo  
XzIhFX6  
public void setSFileName(String value) G
BV]7.  
{ tgKmCI  
sFileName = value; ,~p'p)  
} VD#`1g<  
^ 1}_VB)^  
76(-!Z@=J  
public int getNSplitter() [RTB|0Q  
{ AtGk _tpVZ  
return nSplitter; JL=MlZ  
} k.NgE/;3  
|9$K'+'  
t 5g@t0$  
public void setNSplitter(int nCount) wK!4:]rhG  
{ 18jI6$DY  
nSplitter = nCount; Y1vl,Yi  
} 9l5l"Wj&  
} $fR[zBxA  
L&H4fy!>  
UEbRg =6  
/* RBd{1on  
**Utility.java 6lpfk&  
*/ ;9MsV.n  
package NetFox; OQIQ   
,Y6Me+5B  
v,#*%Gn`%  
public class Utility { =yJJq=!  
pj4M|'
F7  
X`YAJG  
public Utility() B[w~bW|K
 
{ zc%#7"FM  
&W)Lzpx8c  
96x0'IsaG  
} t
>:2F,0K9  
uU=O0?'zq  
//线程睡眠 zZE 2%fqM  
public static void sleep(int nSecond) ;"l>HL:^  
{ t&MJSFkiA  
try{ Z<
T%:F  
Thread.sleep(nSecond); Ke@zS9  
} q^ lx03   
catch(Exception e)  K6d9[;F  
{ (P&~PJH  
e.printStackTrace (); -*t4(wT|j  
} 794V(;sW,  
} g&I/b/A  
[xXa3W  
//日志 ="hh=x.5J  
public static void log(String sMsg) R`sU5:n  
{ >jMq-#*4  
System.err.println(sMsg); i'aV=E5  
} %9Br  
E(N?.i-%$  
`&xo;Vnc  
public static void log(int sMsg) vs}_1o  
{ G41 gil6k  
System.err.println(sMsg); r*CI6yP  
} AdMA|!|:hc  
} -F\xZ  
`&]<_Jc1  
'S]7:/CI  
/* mv
_N ns  
**TestMethod.java ,*ZdMw!  
*/ #
/!fLU@  
package NetFox; !.9pV.~  
}#va#Nb(,  
#-?C{$2I  
public class TestMethod { 0]%0wbY1  
{YnR]|0&  
UZ#Yd|'PD  
public TestMethod() 0*0]RC5?  
{ ///xx/weblogic60b2_win.exe c@H:?s!0R  
try{ G Xx7/X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )* 5R/oy,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g#b[-)Qx  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r:Uqtqxh  
fileFetch.start(); /;>U0~K  
} K8xwPoRL  
catch(Exception e){e.printStackTrace ();} G&8)5d[  
KZ_d..l*W  
,
Yx"3i,  
} L7oLV?k  
jzCSxuZ7O  
2 |lm'Hf  
public static void main(String[] args) ;o*n*N  
{ >;a_
i>[  
new TestMethod(); T1'8<pJ^  
} *9V;;bY#  
} DL0jA/f  
点击下载更多相关资料