http断点续传简单实现（java)

/* NSRY(#3  
**SiteFileFetch.java 9@h-q(-  
*/ !Y^B{bh  
package NetFox; s*CBYzOm  
import java.io.*; 0a?[@ -Sz  
import java.net.*; (F R  
a#Z#-y!  
o9D#d\G  
public class SiteFileFetch extends Thread { kU)E-h  
slA~k;K:_  
w&^Dbme  
SiteInfoBean siteInfoBean = null; //文件信息Bean 6XhS g0s  
long[] nStartPos; //开始位置 l>Zp#+I-  
long[] nEndPos; //结束位置 EffU-=?%!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 tpV61L   
long nFileLength; //文件长度 >\Iy <M  
boolean bFirst = true; //是否第一次取文件 B`%%,SLJ  
boolean bStop = false; //停止标志 >Co@K^'  
File tmpFile; //文件下载的临时信息 I7#+B1t  
DataOutputStream output; //输出到文件的输出流 QUdF`_U7  
2c9]Ja3:6  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ltl(SIi  
public SiteFileFetch(SiteInfoBean bean) throws IOException /h!iLun7I  
{ )Vy}oFT\  
siteInfoBean = bean; `Z#]lS?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =-uk7uZM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g;nPF*(  
if(tmpFile.exists ()) rYA4(rYq  
{ JR/^Go$^  
bFirst = false; D7N` %A8   
read_nPos(); ;Uj=rS`Q  
} \xtmd[7lb<  
else rI1;>/Ir  
{ %lK]m`(  
nStartPos = new long[bean.getNSplitter()]; / ='/R7~  
nEndPos = new long[bean.getNSplitter()]; w5&,AL:  
} #kEa&Se  
jDM^e4U.l  
<7
~+ehu  
e,0Gc-X[B  
} WXE{uGc  
}~o>H a;  
|(1z ?Spbe  
public void run() !bD`2m[Q  
{ A?OaP  
//获得文件长度 YR/rN,  
//分割文件 yu62$d  
//实例FileSplitterFetch
zFV?,"\r  
//启动FileSplitterFetch线程 (/l9@0Y.t  
//等待子线程返回 {-Y% wM8<i  
try{ (}n,Ou[  
if(bFirst) j'JNQo;q  
{ Mi"dFx^Md  
nFileLength = getFileSize(); I_@XHhyVZ  
if(nFileLength == -1) N)Z,/w9  
{ (f|3(u'e?  
System.err.println("File Length is not known!"); Y)4&PN~[  
} ^cF_z}Zi+  
else if(nFileLength == -2) w;Na
9tR  
{
~nG?>  
System.err.println("File is not access!"); JB= L\E}  
} 3 aG?^z  
else $n?@zd@53  
{ J Covk1  
for(int i=0;i<nStartPos.length;i++) 
qTL]  
{ <ibEo98  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9n"
D/NZB  
} \{[Gdj`  
for(int i=0;i<nEndPos.length-1;i++) RcH",*U  
{
~vIQ-|8r:  
nEndPos = nStartPos[i+1]; 1x#Z}XG  
} |};P"&  
nEndPos[nEndPos.length-1] = nFileLength; V'4sOn  
} F+!K9(`|  
} DLv\]\h}L  
.* xaI+:  
D"m]`H  
//启动子线程 EI*B(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gzthM8A  
for(int i=0;i<nStartPos.length;i++) aoh"<I%]>4  
{ /8i3I5*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V!F# ek:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ['~B&  
nStartPos,nEndPos,i); |Psi?'4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dtw4cG  
fileSplitterFetch.start(); .>0j<|~  
} 9""e*-;Mi  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _>8ZL)NQQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8(euWS  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >'^
Tp7\  
nEndPos = " + nFileLength); %(IkUD  
// fileSplitterFetch[nPos.length-1].start(); >M\3tB2C  
w NlC2is  
|gW>D=rkj  
//等待子线程结束 .|Pq!uLvc  
//int count = 0; r(W=1e'  
//是否结束while循环
RG9YA&1ce  
boolean breakWhile = false; Qx-/t9`!Z  
[;`B  
9gFema{U  
while(!bStop) ~.?,*q7  
{ Wp"+\{@)  
write_nPos(); 2HNKq<  
Utility.sleep(500); Fy^=LrH=D  
breakWhile = true; u:Fa1 !4JR  
FA}dKE=c Q  
|N%?7PZ(  
for(int i=0;i<nStartPos.length;i++) );o2eV  
{ |'B-^?;  
if(!fileSplitterFetch.bDownOver) U_t[J|  
{ uOzol~TU)  
breakWhile = false; \&K{v#g~  
break; 1 PL2[_2:  
} ?/Bp8q(  
} P;7JK=~k  
if(breakWhile) cI~uI'  
break; zq1je2DB  
F7!g+LPc<  
i^SuVca  
//count++; V2As 5  
//if(count>4) (gY3?&Ok*  
// siteStop(); {z~n`ow  
} N~rA/B]T  
u^HC1r|%  
}HB>Zb5  
System.err.println("文件下载结束！"); (_h=|VjK(I  
} h$p]M^Z7  
catch(Exception e){e.printStackTrace ();} 6#[  
} . V5Pr}"y  
?VUU[h8"v5  
HSXv_  
//获得文件长度 ;gS)o#v0  
public long getFileSize() ST#9auw  
{ sIUhk7Cd8  
int nFileLength = -1; hkS0ae  
try{ =geopktpf  
URL url = new URL(siteInfoBean.getSSiteURL()); 52X[{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tu5g> qb  
httpConnection.setRequestProperty("User-Agent","NetFox"); j<"@Y7  
Z^tTR]u\$  
+D7>$&BD  
int responseCode=httpConnection.getResponseCode(); pco:]3BF6  
if(responseCode>=400) tx` Z?K[  
{ <}uhKp>*  
processErrorCode(responseCode); b+=@;0p*6B  
return -2; //-2 represent access is error e}f#dR+(  
}
8jBrD1  
4S%s
=vw  
F,dPmR  
String sHeader; [3K& cX}B  
 }?eO.l{  
~F [V  
for(int i=1;;i++) 5#275Hyv  
{ Z "mqH  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a/wg%cWG_  
//Utility.log(in.readLine()); CvOji1  
sHeader=httpConnection.getHeaderFieldKey(i); \wZ 4enm  
if(sHeader!=null) hs;YMUA"  
{
;AH8/M B9  
if(sHeader.equals("Content-Length")) Z;ze{Vb  
{ plNoI1st  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ez1-Nx  
break; 4h*c{do  
} Oj=g;iY  
} rF^H\U:w  
else XWq`MwC9  
break; t6q7w  
} ]D.} /g  
} ;NoiH&  
catch(IOException e){e.printStackTrace ();} Yt!o Hn  
catch(Exception e){e.printStackTrace ();} "cZ){w  
`w8Ejm?n  
d[F3"b%  
Utility.log(nFileLength); 7_9^nDU  
ZGw6Bd_I  
i}L*PCP  
return nFileLength; <@S'vcO  
} %zKTrsMZ  
n-he|u  
#Zg pm"MW  
//保存下载信息（文件指针位置） cy64xR BB  
private void write_nPos() <YM!K8hu$  
{ H73 r3BH  
try{ J4]tT pu"K  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5E#8F  
output.writeInt(nStartPos.length); 6Z@?W  
for(int i=0;i<nStartPos.length;i++) *snY|hF  
{ 5yL\@7u`  
// output.writeLong(nPos); tXCgRU  
output.writeLong(fileSplitterFetch.nStartPos); XZ=%XB:?  
output.writeLong(fileSplitterFetch.nEndPos); WCYVonbg"  
} "]bOpk T  
output.close(); `l'Ine11  
} Z5V_?bm$  
catch(IOException e){e.printStackTrace ();} jL{k!V`s  
catch(Exception e){e.printStackTrace ();} mwMcAUD]2  
} 0}`0!Kv  
|fB/hs \  
sB*!Nf^y  
//读取保存的下载信息（文件指针位置） V)fF|E~0  
private void read_nPos() pK"iTc#\X  
{ *m8{yh
 
try{ *EPJeblAV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |&MOus#v  
int nCount = input.readInt(); 4nXemU=  
nStartPos = new long[nCount]; cpm *m"Nk  
nEndPos = new long[nCount]; 3F8KF`*  
for(int i=0;i<nStartPos.length;i++) *^iSP(dg
 
{ gDjAnz#  
nStartPos = input.readLong(); 3T /_#=9TV  
nEndPos = input.readLong(); b"2_EnE}1  
} B2:GGZ|jS  
input.close(); OD~yIV  
} *Oq&g\K)  
catch(IOException e){e.printStackTrace ();} :7*9W|e  
catch(Exception e){e.printStackTrace ();} Ml,in49  
} f.c2AY~5[  
h%5keiA  
Q yhu=_&  
private void processErrorCode(int nErrorCode) g'9~T8i& ^  
{ VHLt,?G  
System.err.println("Error Code : " + nErrorCode); wkY$J\J  
} l>6p')F!  
u
p]>UX8  
sw50lId  
//停止文件下载
Q]]M;(  
public void siteStop() N+vsQ!Qz  
{ iGBHlw;A  
bStop = true; ky'G/z  
for(int i=0;i<nStartPos.length;i++) )Wk&c8|y  
fileSplitterFetch.splitterStop(); {5 3#Xd  
<
.{OIIuk  
8g?2( MT;  
} }+giQw4  
} '8LHX6FXK  
//负责部分文件的抓取
\1eWI  
**FileSplitterFetch.java J&L#^f*d  
*/ )"g @"LJ=  
package NetFox; \SBAk h  
/PpZ6ne~[  
\Hu?K\SWs  
import java.io.*; (e32oP"  
import java.net.*; WHr:M/qD  
!,~C  
lr[&*v?h  
public class FileSplitterFetch extends Thread { wsj5;(f+  
0IQ|`C.  
0xV[C4E[6  
String sURL; //File URL XcKyrh;i  
long nStartPos; //File Snippet Start Position 0L\vi  
long nEndPos; //File Snippet End Position 6-\C?w A  
int nThreadID; //Thread's ID 7'7o^> !  
boolean bDownOver = false; //Downing is over s5ILl wr  
boolean bStop = false; //Stop identical sh%%U  
FileAccessI fileAccessI = null; //File Access interface .VkLF6  
,%KMi-w]q,  
0Hr)h{!F"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `n
L^]i  
{ Mvk#$:8e  
this.sURL = sURL; 6MbMAh5>  
this.nStartPos = nStart; }S9uh-j6l  
this.nEndPos = nEnd; ~{D:vj4>  
nThreadID = id; Jh%k:TrBm  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^ |>)
H  
} }9?fb[]  
EU()Nnm2  
4OdK@+-8U  
public void run() %/wfYRp*  
{ w&}UgtEm  
while(nStartPos < nEndPos && !bStop) a;0$fRy  
{ #~[mn_C  
5O"wPsl  
(<#Ns W!z  
try{ nmrdqSV  
URL url = new URL(sURL); mWU*}-M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hN_,Vyf  
httpConnection.setRequestProperty("User-Agent","NetFox"); m}nA-*  
String sProperty = "bytes="+nStartPos+"-"; >V3pYRA   
httpConnection.setRequestProperty("RANGE",sProperty);  \4&FW|mx  
Utility.log(sProperty); 7033#
@_  
?T:$:IHw  
#|{^k u  
InputStream input = httpConnection.getInputStream(); 2n5{H fpY  
//logResponseHead(httpConnection); Q"H1(kG|  
HltURTbI  
%LZf=`:(  
byte[] b = new byte[1024];
LQP4#7  
int nRead; E- rXYNfy  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f5QJj<@  
{ !yX4#J(  
nStartPos += fileAccessI.write(b,0,nRead); L}%4YB  
//if(nThreadID == 1) dDla?)F  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \)T4NN  
} lr@H4EJ{  
kzb1iBe 6m  
Xa32p_|5~  
Utility.log("Thread " + nThreadID + " is over!"); Qw
s#v}x
F  
bDownOver = true; a=3{UEi'o  
//nPos = fileAccessI.write (b,0,nRead); O}_Z"y  
} nxh9'"th  
catch(Exception e){e.printStackTrace ();} lGP'OY"Q  
} u.sn"G-c  
} gT6@0ANq  
c/E6}OWA  
o\YF_235  
//打印回应的头信息 .J3Dk=/  
public void logResponseHead(HttpURLConnection con) onj:+zl  
{ hkL[hD  
for(int i=1;;i++) o$DJL11E  
{ W:16qbK  
String header=con.getHeaderFieldKey(i); 3#Hx^H
 
if(header!=null) 3_tO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K)"cwk-  
Utility.log(header+" : "+con.getHeaderField(header)); 4!dN^;Cb  
else DHV#PLbN$  
break; Pc4FEH/  
} If_S_A c  
} Y+tXWN"8  
Mb(aI!;A  
@"#W\m8
 
public void splitterStop() ryq95<l
F  
{ 'L2M W  
bStop = true; j5:{H4?  
} Dyj5a($9"{  
&V&0kp@+  
``A=p<W  
} |mfQmFF  
ODH@/  
r^k:$wJbRK  
/* )[>b7K$f  
**FileAccess.java DT@6Q.  
*//文件访问(定位，写) TK;*:K8oe  
package NetFox; V(Ps6jR"BS  
import java.io.*;  (Ia}]q  
n@xDFa  
)BY\c7SG  
public class FileAccessI implements Serializable{ z2&SZ.mk  
d\dt}&S 5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \z<B=RT\  
RandomAccessFile oSavedFile; O=#FpPHrdw  
long nPos; _1`*&k JL~  
H\2+cAFN#  
31y=Ar""  
public FileAccessI() throws IOException yk9|H)-z  
{ '@M  
this("",0); !c\d(u  
} 3Bz0B a  
]+W+8)f1M  
+n]U3b  
public FileAccessI(String sName,long nPos) throws IOException J56+eC(  
{ n< [np;\  
oSavedFile = new RandomAccessFile(sName,"rw"); 0CxQ@~ttl  
this.nPos = nPos; W 0Q-&4  
oSavedFile.seek(nPos); tgDmHxB]0  
} /
b20!3  
'N],d&fu^^  
_`L,}=um'  
public synchronized int write(byte[] b,int nStart,int nLen) A8hj"V47  
{ UHz*
Tfjb  
int n = -1; LQ?J r>4  
try{ l0g#&V--  
oSavedFile.write(b,nStart,nLen); l'VgS:NT  
n = nLen; Gu<3*@Ng  
} BSG_),AH  
catch(IOException e) J1Mm,LTO  
{ *"0
Yr`)S  
e.printStackTrace (); t(CdoE,6  
} Y*O7lZuF%  
`|i #)  
%WCA?W0:4  
return n; R5G~A{w0  
} "tUXY
Y  
<dDGV>n4;  
qI<6% ^i  
} +}>whyX1  
QR'"Zw&q5/  
JTpKF_Za<  
/* )dG7$,g  
**SiteInfoBean.java W{Ie(hf  
*/ YU[93@mCh  
package NetFox; 6 EE7<&  
Q}W6?XDu  
oKz|hks[6  
public class SiteInfoBean { vyERt^z  
J:'c
j5@  
Us M|OH5k  
private String sSiteURL; //Site's URL
+XJj:%yt  
private String sFilePath; //Saved File's Path +%6{>C+bZo  
private String sFileName; //Saved File's Name C!B2.:ja  
private int nSplitter; //Count of Splited Downloading File "}Ch2K  
}-)2CEj3L%  
v
X)JJ|g  
public SiteInfoBean() X7{ueP#L  
{//nSplitter的缺省值为5 $/5Jc[Ow  
//default value of nSplitter is 5 q+3Z3v  
this("","","",5); cG,B;kMjo  
} 8Cs)_bj#!  
bec n$R  
d[w'j/{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nu}$wLM  
{ <G{m=  
sSiteURL= sURL; Q{UR3U'Q  
sFilePath = sPath; mgL~ $  
sFileName = sName; 4VSlgoz  
this.nSplitter = nSpiltter; .rD@Q{e50  
c#$B;?  
]=2Ba<)m  
} |zKe*H/  
&kHp}\  
E08FUAth]#  
public String getSSiteURL() Ps+0qqT*  
{ MmI4J$F  
return sSiteURL; gV):3mWC  
} yN5g]U.Q  
M3odyO(  
8t!(!<iF0  
public void setSSiteURL(String value) KF|+#qCN  
{  nk>  
sSiteURL = value; mFjX  
} \acJ9N  
A)kx,,[  
JC(rSs*  
public String getSFilePath() T,@.RF  
{ ^rfY9qMJr8  
return sFilePath; zu5'Ex`gQa  
} &
1p\.Y  
@HxEp;*NH"  
%2f``48#  
public void setSFilePath(String value) N#Y%+1  
{ h8Q+fHDYv  
sFilePath = value; ^ ~:f0
2[D  
} .mn`/4  
5DK>4H:  
h$)(-_c3  
public String getSFileName() yQ}$G ,x  
{ l_hM,]T0  
return sFileName; U s86.@|  
} ;n%SjQ'%  
0;2i"mzS\  
P9p:x6  
public void setSFileName(String value) VLC<ju!  
{ +>/ariRr  
sFileName = value; 15+>W4v  
} 'A;G[(SYy  
<vJPKQ`=:  
ns[v.YDL  
public int getNSplitter() GwQW I]  
{ f.JZ[+  
return nSplitter; bXF>{%(}E  
} +~?ze,Di  
b6:A-jb*I  
V>ML-s9  
public void setNSplitter(int nCount) id<i|  
{ :K>v F`SM  
nSplitter = nCount; rl4B(NZi}  
} ZQXv
-"  
} ,A`d!{]5  
JQ=i{
9iJ  
g@wF2=  
/* }IO<Dq=[  
**Utility.java o(w!x!["  
*/ 0<_|K>5dS|  
package NetFox; BZejqDr*  
w`=_|4wFw  
7[h_"@_A7  
public class Utility { x;)bp7
 
JBfDz0P  
i!+D ,O  
public Utility() =F'p#N0_2  
{ ph{p[QI:{X  
:xJ]# t..  
:f%FM&b  
} W
&CQ87b  
(;v)0&h  
//线程睡眠 )]WWx-Uf'  
public static void sleep(int nSecond) KiY
O,nD;\  
{ w}No ^.I*4  
try{ 2w\$}'  
Thread.sleep(nSecond); @Gp=9\L  
} Ck;O59A"&-  
catch(Exception e) ie|I*;#  
{ uT'_}cw  
e.printStackTrace (); JwCv(1$GM  
} ]@X5'r"  
} AzAD76iNv  
2{;&c  
//日志 XndGe=O  
public static void log(String sMsg) x{4Rm,Dxn  
{ 7'u<)V  
System.err.println(sMsg); rt">xVl  
} Ft%HWG
E  
5tPBTS<<"L  
!Ic;;<
 
public static void log(int sMsg) 2WQKj9iyN  
{ [-o`^;  
System.err.println(sMsg); Gt#Jr!N~  
} VD}8ei  
} q-s! hiK  
UjibQl3:m  
HT]W2^k  
/* }OY]mAv-B  
**TestMethod.java XMhDx  
*/ 1d/-SxhZ  
package NetFox; i9Fg  
g8^\|  
*9:oTN  
public class TestMethod { \b{Aj,6,  
`nBCCz'Y!  
f[,9WkC  
public TestMethod() fw>@:m_bK  
{ ///xx/weblogic60b2_win.exe rZRcy9$y>  
try{ fR_ jYP1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q6A!xQs<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TU ]Ed*'&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Pn@k)g  
fileFetch.start(); Rz}?@zh_8  
} ^NJ]~h{n$  
catch(Exception e){e.printStackTrace ();} d,=Kv  
;\`~M  
t~pA2?9@  
} -r/G)Rs  
S,T?(lSl  
;t47cUm6j  
public static void main(String[] args) /CpUq;^  
{ j,Sg?&"%=  
new TestMethod(); ;/i"W  
} `-zdjc d  
} 9xWC<i  
点击下载更多相关资料