http断点续传简单实现（java)

/* G#MdfKH  
**SiteFileFetch.java N5 $c]E  
*/ _Gu- uuy  
package NetFox; n5{Xj:}  
import java.io.*; Uh][@35 p  
import java.net.*; n_'s=]~  
;pnD0bH  
ij?  
public class SiteFileFetch extends Thread { IEU^#=n  
PG,_^QGCX  
A]XZnQ  
SiteInfoBean siteInfoBean = null; //文件信息Bean W^G>cC8.L  
long[] nStartPos; //开始位置 &gjF4~W]  
long[] nEndPos; //结束位置 qbv#I;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q`pP$i:  
long nFileLength; //文件长度
|^A;&//  
boolean bFirst = true; //是否第一次取文件 .jj$Kh q]  
boolean bStop = false; //停止标志 QR>gt;  
File tmpFile; //文件下载的临时信息 '3?\K3S4i  
DataOutputStream output; //输出到文件的输出流 6H'HxB4  
/z}~zO  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6C-z=s)P&  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ox@sI:CT  
{ 1bH;!J  
siteInfoBean = bean; mW:!M!kk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3"O>&Q0c  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U4cY_p?  
if(tmpFile.exists ()) z@wMc EH  
{ {c (!;U  
bFirst = false; og0*Nt+  
read_nPos(); "I QlVi  
} 'D@-  
else O)"gS!,  
{ 9D4NX<_  
nStartPos = new long[bean.getNSplitter()]; &9Xhl''  
nEndPos = new long[bean.getNSplitter()]; Mb]rY>B4  
} ahPoEh  
?.YOI.U^  
sq;s]@~  
Yb
n`3  
} N&M~0iw  
Yh>]-SCw  
1CHeufQ  
public void run() Ry|!p
V  
{ 8KRba4[  
//获得文件长度 6qp%$>$Vt;  
//分割文件 [/X4"D-uOK  
//实例FileSplitterFetch ldp%{"ZZ  
//启动FileSplitterFetch线程 L@gWzC~?Q  
//等待子线程返回 LU9A#  
try{ "70WUx(\t  
if(bFirst) G8;w{-{m  
{ S*n@81Z  
nFileLength = getFileSize(); *f?4   
if(nFileLength == -1) u{*SX k  
{ R~ZFy0  
System.err.println("File Length is not known!"); mL4]l(U  
} J2^'Xj_V  
else if(nFileLength == -2) xl#LrvxI  
{ }oNhl^JC  
System.err.println("File is not access!"); [h,QBz  
} )LyojwY_g  
else 'Tc]KXD6  
{ a|?4)
 
for(int i=0;i<nStartPos.length;i++) >hr{JJe  
{ WH= EPOR,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u&n' ITH  
} uh?>- ]r`  
for(int i=0;i<nEndPos.length-1;i++) BN4_:  
{ kP?KXT3y  
nEndPos = nStartPos[i+1]; Q*b]_0Rb  
} R[;zX(y  
nEndPos[nEndPos.length-1] = nFileLength; -k"^o!p  
} Q^#;
WASi  
}
]X^rU`":  
ph-ATJ"  
L\#<JxY$p  
//启动子线程 @0SC"CqM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $t6e2=7  
for(int i=0;i<nStartPos.length;i++) 8A+SjJ4$  
{ J52 o g4l  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :at$HCaK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x(eb5YS  
nStartPos,nEndPos,i); ruazOmnn~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mzf+Cu:`v  
fileSplitterFetch.start(); FG)$y[*  
} l@ap]R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oD$J0{K6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >`%'4<I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", J;f!!<l\  
nEndPos = " + nFileLength); ,Bal  
// fileSplitterFetch[nPos.length-1].start(); 3fh8$A  
#jxe%2'Ot  
fOMvj%T@2  
//等待子线程结束 ]._LLSzWhg  
//int count = 0; :.45u}[  
//是否结束while循环 }~Af/  
boolean breakWhile = false; /)>s##p*  
kVy\b E0o  
a@0BBihz  
while(!bStop) 6%VV,$p  
{ gw}Mw  
write_nPos(); ~mR'Q-hi<  
Utility.sleep(500); >z.<u|r2  
breakWhile = true; ?|ZTaX6A  
ti<;7Yb  
D7S'*;F  
for(int i=0;i<nStartPos.length;i++) `8
Lo{P  
{ Z%n(O(^L  
if(!fileSplitterFetch.bDownOver) ZE/o?4k*c1  
{ FTeu~<KpM  
breakWhile = false; UF@XK">  
break; P'O#I}Dmw<  
} W[^qa5W<FB  
} C|?o*fQ  
if(breakWhile) /0eYMG+K=  
break; izx#
3u$P  
37RLE1Yf  
"|HDGA5  
//count++; T0]*{k(FR  
//if(count>4) ]7/ b/J  
// siteStop(); 
eVM/uDD  
} dF~8XYo  
>~Qr  
u3o#{~E/#  
System.err.println("文件下载结束！"); _Y[jyD1>  
} 56Vb+0J'  
catch(Exception e){e.printStackTrace ();} PtTHPAKj  
} (S v~2  
$&2UTczp  
j8sH#b7Z  
//获得文件长度 /-i!;!  
public long getFileSize() 6HlePTf8  
{ ,yTjU{<"  
int nFileLength = -1; <fs2fTUeqF  
try{ -Fn}4M  
URL url = new URL(siteInfoBean.getSSiteURL()); 0]jA<vLR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fks)+L'  
httpConnection.setRequestProperty("User-Agent","NetFox"); \2vg{  
i}~SDY  
Y9`5G%  
int responseCode=httpConnection.getResponseCode(); ;IpT} ,  
if(responseCode>=400) ]7rj/l$u  
{ q`G,L(  
processErrorCode(responseCode); +L5\;  
return -2; //-2 represent access is error Dxk+P!!K  
} @GvztVYo  
-> J_ ~  
C*G=cs\i  
String sHeader; ,do58i K  
=Z+nX0qF  
N72Yq)(  
for(int i=1;;i++) g9Yz*Nee<  
{ ":nQgV\9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ymNnkFv  
//Utility.log(in.readLine()); E!O\87[  
sHeader=httpConnection.getHeaderFieldKey(i); bUY>st'  
if(sHeader!=null) r lKlpl  
{ 3<=G?of  
if(sHeader.equals("Content-Length")) l]]l  
{ "rAY.E]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (4%YHS8  
break;  PTS]7  
} d O~O |Xsb  
} ehA;i.n  
else Gxax2o  
break; leCVK.  
}
$.:mai  
} 3.)b4T  
catch(IOException e){e.printStackTrace ();} -`Y:~q1
 
catch(Exception e){e.printStackTrace ();} :>81BuMvg  
<vUVP\u~$  
<s@-:;9~  
Utility.log(nFileLength); \`w4|T  
P6Mhbmt9*  
zW8*EE+,  
return nFileLength; o-cAG{.WC  
} J4YBqp  
WGAXIQ  
{ccIxL /~  
//保存下载信息（文件指针位置） nPUqMn'  
private void write_nPos() e2-Dq]p  
{ pDhse2  
try{ g`>og^7g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :L 3&FA  
output.writeInt(nStartPos.length); J# kl 7
 
for(int i=0;i<nStartPos.length;i++) 1h7+@#<:a  
{ 3u33a"nL8  
// output.writeLong(nPos); auWXgkwZs/  
output.writeLong(fileSplitterFetch.nStartPos); Bg8#qv  
output.writeLong(fileSplitterFetch.nEndPos); ?U7) XvQ  
} ,pBh`av  
output.close(); /b;K  
} cubUq5  
catch(IOException e){e.printStackTrace ();} g-vg6@6  
catch(Exception e){e.printStackTrace ();} jw ,izxia  
} #?B%Ja% ;W  
ir3VTqz  
yGpz,X4x  
//读取保存的下载信息（文件指针位置） .C]cK%OO N  
private void read_nPos() [/RM=4Nh5  
{ )$Z(|M4  
try{ FP"$tt(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); smQVWs>  
int nCount = input.readInt(); z{]?h cY  
nStartPos = new long[nCount]; V84*0&qOW  
nEndPos = new long[nCount]; XUV!C7  
for(int i=0;i<nStartPos.length;i++) +'
oX  
{  StYzGJ  
nStartPos = input.readLong(); 6yAA~;*5'  
nEndPos = input.readLong(); [t0rfl{.  
} v0l_w  
input.close(); eXl=i-'  
} #:ns64|  
catch(IOException e){e.printStackTrace ();} !~-6wN"k  
catch(Exception e){e.printStackTrace ();} jQj,q{eA  
} 'b"TH^\  
%zo= K}u  
\0FT!} L  
private void processErrorCode(int nErrorCode) `&$B3)Eb  
{ 7k=fZ$+O  
System.err.println("Error Code : " + nErrorCode); sP$Ks#/  
} gd6Dm4q(  
XT@Mzo49z\  
gmSQcN)  
//停止文件下载 0NO1M)HQv  
public void siteStop() RM*f|j  
{ 0&fl#]oCE  
bStop = true; /owO@~G  
for(int i=0;i<nStartPos.length;i++) PQj<[rY
 
fileSplitterFetch.splitterStop(); :wgfW .w  
-g`IH-B  
J^3H7 ]  
} vH?9\3  
} CP` XUpX`&  
//负责部分文件的抓取 (xyS7q]m  
**FileSplitterFetch.java 8TZENRzx-|  
*/ Lu>H`B7Q"  
package NetFox; nwM)K
 
h ; kfh.  
)%JD8;[Jq  
import java.io.*; <`g3(?  
import java.net.*; E(L<L1:"  
Ttv9"z  
;rBp1[qVe  
public class FileSplitterFetch extends Thread { 5JFV%odo  
:%-,Fxl4  
oO=o|w|T  
String sURL; //File URL 7!2 HNg  
long nStartPos; //File Snippet Start Position BgRZ<B`  
long nEndPos; //File Snippet End Position 3x5!a5$Y  
int nThreadID; //Thread's ID %AR^+*Nu  
boolean bDownOver = false; //Downing is over %%g-GyP 1  
boolean bStop = false; //Stop identical {K7YTLWY  
FileAccessI fileAccessI = null; //File Access interface 0rzVy/Z(  
_ 6:ww/  
%cW;}Y[?P  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException J4yt N3  
{ QB1M3b  
this.sURL = sURL; Q_}/ Pn$1  
this.nStartPos = nStart; ; Zq/eiB  
this.nEndPos = nEnd;  93w~.p  
nThreadID = id; yr4ou  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 W(&6  
} ?q%b*Ek  
C+l?k2  
HZ\k-!2  
public void run() IL2r9x%  
{ lfy7w|  
while(nStartPos < nEndPos && !bStop) AQ@v>wr}  
{ NJ$e6$g)  
_bI+QC#   
%D^bahf  
try{ &`@M8-m#F  
URL url = new URL(sURL); /4C`k=>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eF1.VLI  
httpConnection.setRequestProperty("User-Agent","NetFox"); yDtOpM8<{  
String sProperty = "bytes="+nStartPos+"-"; $pFk"]=  
httpConnection.setRequestProperty("RANGE",sProperty); f9'] jJ+  
Utility.log(sProperty); 6q%ed UED  
}aZrou3E  
sb'p-Mj  
InputStream input = httpConnection.getInputStream(); _pSIJ3O  
//logResponseHead(httpConnection); FDq{M?6i  
(2%>jg0M  
5\G)Q<A]*L  
byte[] b = new byte[1024]; ]_2yiKv&  
int nRead; t:9 ZCu ay  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) },6*Y*?{  
{ J~dTVBx  
nStartPos += fileAccessI.write(b,0,nRead); o>!JrH  
//if(nThreadID == 1) N5\{yV21",  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #Wx=v$"  
} OROqT~6G  
rv?!y8\  
2nx9#B*/T  
Utility.log("Thread " + nThreadID + " is over!"); vPsq<l}  
bDownOver = true; X,Zd=
 
//nPos = fileAccessI.write (b,0,nRead); #{w5)|S#JD  
} g8Aj `O  
catch(Exception e){e.printStackTrace ();} D-iUN  
} 5bBCpNa  
} DR{]sG  
6S_y%8Fv&[  
0UD"^zgY  
//打印回应的头信息 1"$R 3@s;  
public void logResponseHead(HttpURLConnection con) tDU}rI8?  
{ ;z0"Ox=7  
for(int i=1;;i++) bm6hZA|  
{ <_f`$z  
String header=con.getHeaderFieldKey(i); uRGB/ju^E  
if(header!=null) @Mr}6x*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); R2Yl)2 D  
Utility.log(header+" : "+con.getHeaderField(header)); \-G5l+!  
else u
Tw|Q{f  
break; &oc_a1R  
} D1! {S7  
} /Tcb\:`9  
7*g(@d  
zf7rF}  
public void splitterStop() M1gP R  
{ Fd}<Uote3  
bStop = true; ?N2X)Y@yi  
} {DS\!0T-X  
Vs|sw  
+/}_%Cf8  
} (L:`ojiU  
&]*|6cR$E  
j aD!  
/* Q_v\1"c  
**FileAccess.java gb9[Meg'  
*//文件访问(定位，写) <%/:w/  
package NetFox; o6/Rx#A  
import java.io.*; F\Y,JUn[G  
v2(U(Tt  
u IF$u  
public class FileAccessI implements Serializable{ SCI1bMf  
ha5 bD%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 FQQ@kP$.  
RandomAccessFile oSavedFile; tgK x4  
long nPos; at=D&oy4"+  
tw]/,>\G  
a2[8wv1  
public FileAccessI() throws IOException $u&|[vcP0  
{ N]V/83_  
this("",0); OM1*I
y  
} .r(^h/IF  
!>q?dhw@  
,v|CombIc.  
public FileAccessI(String sName,long nPos) throws IOException }]tFz}E\  
{ jjYM3LQcdP  
oSavedFile = new RandomAccessFile(sName,"rw"); Ko]QCLL  
this.nPos = nPos; >@z d\}@W  
oSavedFile.seek(nPos); 8IpxOA#jQ  
} l#p}
{  
m\/>C|f\  
P4i3y{
$V  
public synchronized int write(byte[] b,int nStart,int nLen) F
ZM2   
{ /cM 5  
int n = -1; u0wn=Dg  
try{ Ck:#1-t8{  
oSavedFile.write(b,nStart,nLen); vuAQm}A4'g  
n = nLen; Ri9Kr  
} ,0BR-#  
catch(IOException e) o?;F.W_  
{ 9e0C3+)CY  
e.printStackTrace (); U0!^m1U:  
} z7| s%&  
\nrgAC-b  
Fecx';_1`  
return n; \FIa,5k8  
} Gv!BB=ir(  
#4Dn@Gqh.Y  
|if~i;VKL  
} B>{|'z?%>  
PbbXi  
lv=yz\  
/* y;zt_O/  
**SiteInfoBean.java ~8XX3+]z:X  
*/ hN Z4v/  
package NetFox; vsu@PuqH  
x%_qJ]o  
oNiToFbQu  
public class SiteInfoBean { JZWgr&O<  
[`y:M&@  
i_[^s:*T  
private String sSiteURL; //Site's URL |De!ti  
private String sFilePath; //Saved File's Path aQ32p4C  
private String sFileName; //Saved File's Name -3C* P  
private int nSplitter; //Count of Splited Downloading File DZ%g^D
RZX  
nYI/&B{p  
oq=?i%'>  
public SiteInfoBean() sKe9at^E]>  
{//nSplitter的缺省值为5 %'RI3gy  
//default value of nSplitter is 5 gJ<@;O8zu0  
this("","","",5); "Cz
z,;0  
} >2]Eaw&W  
+io;K]C  
6(ka"Vu~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) WF+bN#YJ  
{ } l:mN  
sSiteURL= sURL; "[%;B0J  
sFilePath = sPath; [z W_%O kP  
sFileName = sName; mXxZM;P[  
this.nSplitter = nSpiltter; LFk5rv'sM0  
V-?sek{;  
UgF)J  
} _7-"VoX  
t!J";l  
d[s;a.  
public String getSSiteURL() 30sC4}   
{ +Fu@I{"A  
return sSiteURL; K$Mx}m7l  
} c7FfI"7HR  
W _PM!>8`  
n4ds;N3Hd  
public void setSSiteURL(String value) ?c|`R1D  
{ 
377j3dP  
sSiteURL = value; "@c';".|  
}
ef;&Y>/  
C$N4  
(&9DB  
public String getSFilePath() zxk??0]/  
{ IQ(]66c,  
return sFilePath; xWC\954  
} WU+Jo@]y  
NDs]}5#   
;[WSf{k  
public void setSFilePath(String value) sx;V,"Y  
{ <2o.,2?G  
sFilePath = value; N=O+X~  
} gTmUK{y'  
+(QMy&DtS  
[#STR=_f  
public String getSFileName() :=iM$_tp'  
{ h-?q6O/|  
return sFileName; \dp9@y[^  
} giPhW>  
)|{1&F1  
=u
:6b} =  
public void setSFileName(String value) l ))~&  
{ ;EE&~&*w  
sFileName = value; 5Gw!9{ke  
} v2Qc}o  
PO1:9  
07T;IV3#C5  
public int getNSplitter() W[1f]w3  
{ 7(|3 OR+  
return nSplitter; Ads<-.R  
} LAK-!!0X  
<QkN}+B=  
6'No4[F 4n  
public void setNSplitter(int nCount) JucxhjV#,  
{ Pw^c2TQ  
nSplitter = nCount; :ET3&J L  
} ! 6p)t[s  
} :~0^ib<v;  
o$HJg  
|`94Wj<  
/* 7n\j"0z  
**Utility.java (4{@oM#H6  
*/ oQ-|\?{;A  
package NetFox; hD6ur=G8u  
Jc"$p\ $-  
11@2;vw  
public class Utility { LjH&f 4mY  
 $D, wO  
FkxhEat8  
public Utility() TReM
8Vd  
{ ku[=QsMv  
X>@.-{6T  
iu6WGmR  
} Z@.ol Y  
}ygb
gyLa  
//线程睡眠 TgQ|T57  
public static void sleep(int nSecond) ,# jOf{L*  
{ N?mY|x\}wK  
try{ g]@R'2:1  
Thread.sleep(nSecond); Cs1%g  
} Nz>E#.++  
catch(Exception e) iM\ZJ6  
{ Y9H *S*n  
e.printStackTrace (); ev;5?9\E  
} "-j@GCme  
} I3zitI;  
,QHx*~9  
//日志 M#lVPXS  
public static void log(String sMsg) G5QgnxwP2  
{ /nMqEHCyg  
System.err.println(sMsg); Vm1c-,)3  
}
)ejXeg  
&PQ{e8w  
e/HX,sf_g  
public static void log(int sMsg) ZAo)_za&mH  
{ Y%?!AmER  
System.err.println(sMsg); $Pb[c%'  
} |E_+*1lq.  
} r/q1&*T  
;cm{4%=Iqe  
p3A-WK|NX  
/* AZ]SRz9mKY  
**TestMethod.java ]-s`#  
*/ _9O }d  
package NetFox; i2ml[;*
,N  
_qzo):G.s  
4Tzu"y  
public class TestMethod { ry'^1~,  
&A5[C{x  
TNPGw!  
public TestMethod() FO'. a  
{ ///xx/weblogic60b2_win.exe
ZV<y=F*~f  
try{ Ff#N|L'9_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %C
E@}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k#=leu"I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8DS5<  
fileFetch.start(); ;'
18  
} Q-dHR i
  
catch(Exception e){e.printStackTrace ();} wgR@M[]o;  
CL}I:/zRB  
TcKKI  
} ?e_}X3{  
wPO@f~[Ji  
?L#SnnE  
public static void main(String[] args) /h.3<HI."*  
{ (b2^d  
new TestMethod(); D>x'3WYR  
} S~(VcC$K  
} $Q$d\Yvi  
点击下载更多相关资料