http断点续传简单实现（java)

/* =!m}xdTP  
**SiteFileFetch.java )G7=G+e;  
*/ :W@#) 1
=  
package NetFox; Kt0(gQOr0  
import java.io.*; ?'"X"@r5  
import java.net.*; U\rh[0  
y,pZTlE  
cWajrLw  
public class SiteFileFetch extends Thread { 1,5E`J  
4Z|vnj)Z  
~
SSU`  
SiteInfoBean siteInfoBean = null; //文件信息Bean JF/,K"J  
long[] nStartPos; //开始位置 1He{v#  
long[] nEndPos; //结束位置 @AYRiOodi  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 l|5fE1K9U  
long nFileLength; //文件长度 ;\MW$/[JCy  
boolean bFirst = true; //是否第一次取文件 [%&ZPJT%i  
boolean bStop = false; //停止标志 % >;#9"O4  
File tmpFile; //文件下载的临时信息 g:0#u;j^7  
DataOutputStream output; //输出到文件的输出流 Zf5`XslA.  
'H7x L  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） d,$d~alY  
public SiteFileFetch(SiteInfoBean bean) throws IOException `yF`x8  
{ !z{-?o/  
siteInfoBean = bean; z4E|Ai  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); kF>o.uSV  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {)AMwq  
if(tmpFile.exists ()) >hH0Q5aL  
{ ,ZS6jZ  
bFirst = false; !a$ D4(`v  
read_nPos(); 2Hum!p:1  
} $4MrP$4TI  
else ~zHg[X*  
{ >c-fI$]  
nStartPos = new long[bean.getNSplitter()]; @xc',I  
nEndPos = new long[bean.getNSplitter()]; :R.&`4=X  
} (RtueEb.~E  
{647|j;e  
&F}"Z(B<wK  
ttXjn  
} L,;D@Xi  
<W]g2>9o9  
];%0qb  
public void run() KsrjdJx, '  
{ 2
YuN~-  
//获得文件长度 !gnj]k&/c  
//分割文件 o->\vlbD  
//实例FileSplitterFetch nL:SG{7  
//启动FileSplitterFetch线程 Zf7&._y.  
//等待子线程返回 fIGFH
Zy,  
try{ e|4&b@  
if(bFirst) >MJg ,  
{ LW:o8ES33  
nFileLength = getFileSize(); Z/rTVAs@r  
if(nFileLength == -1) #yI.nzA*  
{ "n:{!1VGw  
System.err.println("File Length is not known!"); )etmE  
} c%*($)#  
else if(nFileLength == -2) U:F/iXz  
{ 4.RG4Jq  
System.err.println("File is not access!"); ~XeFOMq  
} *Ei|fe$sa  
else PA w-6;  
{ %<8nF5  
for(int i=0;i<nStartPos.length;i++) !A1)|/a@  
{ 6dAEM;$_Z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); - y9>;6  
} n}xhW'3hU=  
for(int i=0;i<nEndPos.length-1;i++) $;G{Pyp  
{ /=uMk]h  
nEndPos = nStartPos[i+1]; r}yG0c,  
} %r)avI  
nEndPos[nEndPos.length-1] = nFileLength; fFjH "2WD  
} Il.Ed-&62  
} P6,7]6bp  
j]0^y}5f+s  
HyiFy7j  
//启动子线程 }bU8G '  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fA48(0p  
for(int i=0;i<nStartPos.length;i++) 80M;4nH^5  
{ mW%?>Z1=>d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kj5Q\
vr)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BK
,sc'b  
nStartPos,nEndPos,i); l<(Y_PE:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~7!7\i,Y8\  
fileSplitterFetch.start(); N)% ;jh:T  
} drwg
jLC+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3\;27&~gV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); x{}z ;yG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v6\F Q9|t  
nEndPos = " + nFileLength); 9
dh>l!2  
// fileSplitterFetch[nPos.length-1].start();

(J"T]-[  
FI8Oz,  
fQ+VT|jzx  
//等待子线程结束 [~D|peM3  
//int count = 0; :`)~-`_  
//是否结束while循环 M\b")Tu{0  
boolean breakWhile = false; UueD
(T;p  
z=&z_}M8  
0:KE@=  
while(!bStop) e$c?}3E!z  
{ <ktzT&A  
write_nPos(); 4;`Bj:.  
Utility.sleep(500); j\RpO'+}  
breakWhile = true; M9!AIHq4  
a:YI"*S  
_B2V "p  
for(int i=0;i<nStartPos.length;i++) >*twTlb{  
{ Wl^R8w#Z$  
if(!fileSplitterFetch.bDownOver) T2?HRx  
{ E99CmG|"  
breakWhile = false; ^5=UK7e5KY  
break; sM1RU  
} $V6^G*Q  
} bshGS8O  
if(breakWhile) -G &_^"=R  
break; HEqWoV]{d  
/W#O +  
3>z[
PPw  
//count++; RnfXN)+P  
//if(count>4) 6)\dBOz  
// siteStop(); mxwdugr`  
} 2WM\elnA  
u!N{y,7W)  
KRsAv^']  
System.err.println("文件下载结束！"); I>h<b_y  
} *0Gz)'  
catch(Exception e){e.printStackTrace ();} 0h$GI"dR  
} i54md$Q^  
{mE! Vf  
p<WFqLe(":  
//获得文件长度 XC15K@K  
public long getFileSize() vjViX<#(V  
{ puJ#w1!x`  
int nFileLength = -1; V%
HS\<$h  
try{ 'k&?DZ!  
URL url = new URL(siteInfoBean.getSSiteURL()); .DJDpP)M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f<y&\'3  
httpConnection.setRequestProperty("User-Agent","NetFox"); u}9fj  
h$C@j~  
DJh&#b  
int responseCode=httpConnection.getResponseCode(); u"$a>S_  
if(responseCode>=400) J3S&3+2G  
{ r0m)j  
processErrorCode(responseCode); T#:F]=  
return -2; //-2 represent access is error vd#,DU=p!  
} LU!1s@  
~!%0Z9>ap  
iZ[tHw||  
String sHeader; k7_I$<YDj  
Z#`0txCF  
UkR3}{i  
for(int i=1;;i++) A,~Hl
w  
{ )Du-_Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); IKvBf'%-  
//Utility.log(in.readLine()); z)F#u:t  
sHeader=httpConnection.getHeaderFieldKey(i); `NwdbKX  
if(sHeader!=null) oL/o*^  
{ (U.**9b;  
if(sHeader.equals("Content-Length")) FYPz 4K  
{ YTY%#"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4YbC(f  
break; ZofHic  
} U2*6}c<  
} ^o<:;{  
else 0rMqWP
 
break; .")b?#K  
} o%(bQV-T  
} FN"rZWM  
catch(IOException e){e.printStackTrace ();} +?-qfp,:0  
catch(Exception e){e.printStackTrace ();} b5ie <s  
UPCQs",  
ZcPUtun  
Utility.log(nFileLength); (b/d0HCND  
MM#cLw  
&jts:^N>  
return nFileLength; #dJ 2Q_2  
} PNF4>)  
AvRcS]@=  
Wb=Jj 9;  
//保存下载信息（文件指针位置） 4sY[az  
private void write_nPos() 9rj('F&1  
{ OK
Y+M^PP  
try{ f[/.I,9U^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hd^x}iK"  
output.writeInt(nStartPos.length); G_oX5:J*  
for(int i=0;i<nStartPos.length;i++) 0*(K DDv  
{ GXb47_b^  
// output.writeLong(nPos); +}!DP~y+  
output.writeLong(fileSplitterFetch.nStartPos); }X1.Wt=?  
output.writeLong(fileSplitterFetch.nEndPos); 2o{@nN8%  
} %= u/3b:o  
output.close(); Rlg#z4m  
} P!+v:'P5f  
catch(IOException e){e.printStackTrace ();} okBE|g  
catch(Exception e){e.printStackTrace ();} uI
P iM8(  
} cIw eBDl  
;bHfn-X  
hjY0w  
//读取保存的下载信息（文件指针位置） l=Wd,$\  
private void read_nPos() \ZnN D1A  
{ IlHY%8F{  
try{ H/i<_LP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <Ry$7t,  
int nCount = input.readInt(); u7k|7e=xk  
nStartPos = new long[nCount]; Jirct,k  
nEndPos = new long[nCount]; G:+16XCra  
for(int i=0;i<nStartPos.length;i++) QP\yaPE  
{ \.>.c g  
nStartPos = input.readLong(); g37q/nEv  
nEndPos = input.readLong(); ;/Q6i  
} AUAI3K?  
input.close(); d7~j^v)=^  
} &telCg:  
catch(IOException e){e.printStackTrace ();} _om[VKJd  
catch(Exception e){e.printStackTrace ();} [,7-w  
} ('WY5Yps  
D9^7m j?e  
oeNzHp_  
private void processErrorCode(int nErrorCode) #\b ;2>  
{ a>b8-j=J  
System.err.println("Error Code : " + nErrorCode); PRpE$`WK  
} p37|zX  
^gm>!-Gx  
AP@<r  
//停止文件下载 3i(Jon/p  
public void siteStop() + zDc  
{ 4Iq5+Q  
bStop = true; VG\
mo?G  
for(int i=0;i<nStartPos.length;i++) F!R2_89iy  
fileSplitterFetch.splitterStop(); " dT>KQ  
`cO|RhD@  
*aG"+c6|  
} *:#Z+7x ]  
} p"KV*D9b  
//负责部分文件的抓取 h2&y<Eg>  
**FileSplitterFetch.java )d_U)b7i  
*/ BvI 0v:  
package NetFox; CXa Ld7nMX  
RO$*G jQd  
]+lF=kkc%  
import java.io.*; \4@a  
import java.net.*; ^?sSx!:bZ  
V g6S/-  
]Da4.s*mW  
public class FileSplitterFetch extends Thread { +U=KXv  
u7u~  
p|s2G~0<  
String sURL; //File URL s[Gswd  
long nStartPos; //File Snippet Start Position <)J55++  
long nEndPos; //File Snippet End Position }6@%((9E2  
int nThreadID; //Thread's ID +WdL  
boolean bDownOver = false; //Downing is over 4L
$};L  
boolean bStop = false; //Stop identical /xf.\Z7<  
FileAccessI fileAccessI = null; //File Access interface U TS{H  
85Dm8~  
/gX%ABmS  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ebD{ pc`&  
{ 5E.vje{U
;  
this.sURL = sURL; U5clQiow  
this.nStartPos = nStart; No~6s.H  
this.nEndPos = nEnd; =ty2_6&>  
nThreadID = id; X$PS(_M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;Lqm#]C  
} _]_LF[  
a^x  0 l  
ja:\W\xhJ  
public void run() 5 Af?Yxv  
{ v'$ykZ!Z  
while(nStartPos < nEndPos && !bStop) 4zwif&  
{ _&=9Ke
  
?9qAe  
65t[vi*C  
try{ b2W;|  
URL url = new URL(sURL); eoJFh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G*=H;Upi  
httpConnection.setRequestProperty("User-Agent","NetFox"); <@%ma2  
String sProperty = "bytes="+nStartPos+"-"; 8m \;P  
httpConnection.setRequestProperty("RANGE",sProperty); 8W{ g  
Utility.log(sProperty); gi '^qi2  
W >Kp\
tD  
!Am =v=>  
InputStream input = httpConnection.getInputStream(); nT)~w s  
//logResponseHead(httpConnection); BHIM'24bp  
l2r>|CGQ[  
s?HsUD$b  
byte[] b = new byte[1024]; r@
;$V_I  
int nRead; %va[jJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) U<|B7t4M  
{ HN^w'I'bp  
nStartPos += fileAccessI.write(b,0,nRead); $*wu~  
//if(nThreadID == 1) a3*.,%d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _5
Bu [I  
} n/Or~@pHD  
MR[N6E6Mg  
&,F elB0*  
Utility.log("Thread " + nThreadID + " is over!"); 40rZ~!}  
bDownOver = true; 1ME|G"$;  
//nPos = fileAccessI.write (b,0,nRead); !(}OBZ[*  
} 9B& }7kk  
catch(Exception e){e.printStackTrace ();} /^NJ)9IB  
} Z#%}K Z  
} "rL"K  
Sw/J+FO2  
A<]&JbIt  
//打印回应的头信息 Xk;Uk
[  
public void logResponseHead(HttpURLConnection con) wX@H &)<s  
{ L/c4"f|.*v  
for(int i=1;;i++) T$f:[ye]Z  
{ zv&ePq\#  
String header=con.getHeaderFieldKey(i); `AB~YX%(  
if(header!=null) '! #On/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L,tZh0  
Utility.log(header+" : "+con.getHeaderField(header)); -<H ri5  
else 6Uch0xha!  
break; p^}L  
} L)@`58Eil  
} iz,]%<_PE  
l A 0-?k  
^V_ku@DY  
public void splitterStop() x4/T?4k  
{ Bi %Z2/  
bStop = true; /YS@[\j4  
} Jx)~kK  
hYs82P|2Ol  
?=TL2"L  
} +!D=SnBGs  
*1%e%G  
@#'yPV1  
/* 02;f2;I  
**FileAccess.java {(8U8f<'=y  
*//文件访问(定位，写) YWybPD4\(  
package NetFox;  >cC Gx  
import java.io.*; !k4 }v'=  
AEiWL.*.  
v#{G8'+%  
public class FileAccessI implements Serializable{ )*"T  
mrw]yu;2<n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8') .ohD  
RandomAccessFile oSavedFile; R?1i
dl)  
long nPos; W*1d X"S  
ee4KMS  
nNkyOaK*4  
public FileAccessI() throws IOException :Bdipc  
{ b\<lNE!L  
this("",0); y8Ei=[  
} `NYF?%  
//ne']L  
^Tb}]aHg  
public FileAccessI(String sName,long nPos) throws IOException ^p{A!I!  
{ ){?mKB5  
oSavedFile = new RandomAccessFile(sName,"rw"); u?LW+o  
this.nPos = nPos; ez{P-
qB  
oSavedFile.seek(nPos); l"2^S6vU  
} >eYU$/80  
O7Y P_<,#  
PT 0Qzg  
public synchronized int write(byte[] b,int nStart,int nLen) F5:2TEA  
{ T)
$6H}[c  
int n = -1; Z1XUYe62  
try{ R!:eYoQ  
oSavedFile.write(b,nStart,nLen); OqAh4qa,$  
n = nLen; m70`{-O  
} s{x*~M$vt  
catch(IOException e) cij]&$;Q  
{ K|P9uHD  
e.printStackTrace (); uK+9gTv  
} \;A50U|r  
# CP9^R S  
7UeE(=Hr5  
return n; ,n /SDEL  
} 1Xk{(G<\  
c+)36/; X  
kMfc"JXF  
} dXf]G6  
OX#eLco  
o(v"?Y6  
/* &etL&s v  
**SiteInfoBean.java 0xvMR&.H  
*/ Cy`<^_i  
package NetFox; F)[XIY&2/  
s0X/1Cq  
HM(bR"E  
public class SiteInfoBean { -52@%uB  
TsFV ;Sl3  
kx;xO>dC  
private String sSiteURL; //Site's URL B` t6H  
private String sFilePath; //Saved File's Path 8gu'dG=  
private String sFileName; //Saved File's Name 02]8|B(E90  
private int nSplitter; //Count of Splited Downloading File Fyi?,,  
y{&{=1#  
5p#o1I
 
public SiteInfoBean() iZDb.9@&t  
{//nSplitter的缺省值为5 !>a&`j2:W  
//default value of nSplitter is 5  8o%<.]   
this("","","",5); df21t^0/  
} ~:ub  
U#UVenp@  
Kd AR)EU>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )e
TnR:=  
{ nsr _\F\  
sSiteURL= sURL; @4W\RwD  
sFilePath = sPath; di)noQXkB-  
sFileName = sName; 'AAF/9  
this.nSplitter = nSpiltter; EDPI*@>  
x0AqhT5}  
O|^6UH  
} 4X(1  
'aSZ!R  
@vQ;>4i.  
public String getSSiteURL() wt_?B_n
R  
{ nkr,  
return sSiteURL; 1A)wbH)  
} kcma/d  
WL]Wu.k  
)M|O;~q  
public void setSSiteURL(String value) ^Xt]wl*]+  
{ H;b
'"./  
sSiteURL = value; P}.yEta  
} ]6i_d  
Wj  
^)%wq@Hi  
public String getSFilePath() a-UD_|!  
{ (A
y4B*|!  
return sFilePath; g O\f:Pg  
} qI4R`P"  
}{w_>!ee  
+i q+  
public void setSFilePath(String value) $J;=Ux)$  
{ fO^EMy\  
sFilePath = value; am$-sh72  
} =`7)X\i@z  
nfd?@34"A2  
!kHyLEV  
public String getSFileName() ,pGCgOG#}c  
{ u1pYlu9IW  
return sFileName; VW<"c 5|  
} NZw[.s>n  
J~yd]L>  
*fuGVA  
public void setSFileName(String value) zM9).D H  
{ 644hQW&W  
sFileName = value; AIRVvW~($  
} zvQ^f@lq2  
Sj]T{3mi  
D.oS8'   
public int getNSplitter() R(7X}*@X  
{ !~$YD*"S  
return nSplitter; Ik@Q@ T"  
} gYH:EuY,  
vI:bl~  
,{mf+ 3&$,  
public void setNSplitter(int nCount) w3]0 !)t1  
{ u_/OTy  
nSplitter = nCount; 'mY,>#sT  
} q%=7<( w  
} "`1of8$X7  
W)Kpnb7  
#9W5
 
/* PUFW^"LV  
**Utility.java .o,51dn+ s  
*/ ekk&TTp#  
package NetFox; MkV*+LXC  
GWkJ/EX  
(j"~]T!)1  
public class Utility { y8(?:#ZC  
,ex(pmZ;  
PB3!;  
public Utility() VkP:%-*#v  
{ Xm:gD6;9  
Iy1XnS*  
C_khd"  
} !^"!fuoNC  
]@<3 6ByM  
//线程睡眠 |Nx!g fU  
public static void sleep(int nSecond) K&a]pL6D  
{ {]_{BcK+  
try{ cI4qgV  
Thread.sleep(nSecond); Z=/L6Zb  
} gJ[q {b  
catch(Exception e) 'r?HL;,q  
{ MFdFZkpiV  
e.printStackTrace (); eJ)KE5%n#  
} Bc"}nSjH  
} <T2~xn  
R7;rBEt8  
//日志 ,;ruH^  
public static void log(String sMsg) BO\`m%8md  
{ Er+3S@sfq,  
System.err.println(sMsg); H/la'f#o%  
} O |I:[S},  
m&jt[   
q ]R @:a/  
public static void log(int sMsg) (LvOs
r~  
{ *p5T  
System.err.println(sMsg); h'q0eqYeu)  
} _R<V8g1f  
} uc(yos  
\S@=zII_  
Z$=$oJzB  
/* ujp,D#xHP  
**TestMethod.java eq 1 4  
*/ t:j07 ,1~  
package NetFox; 6%hEs6-R  
[,?A
$Z*Z|  
f+88R=-u6S  
public class TestMethod { .$s|T  
nF y7gA|  
xbH!:R;  
public TestMethod() $8ww]}K  
{ ///xx/weblogic60b2_win.exe A5H8+gATK  
try{ k49n9EX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); c68$pgG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); RknSWuFKt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Gqz)='  
fileFetch.start(); J<:D~@qq  
} :bF2b..XOu  
catch(Exception e){e.printStackTrace ();} %|6Q7'@p  
7z0uj  
WMRgf~TY=2  
} )^2jsy -/  
f%%En5e+  
i@?<]n  
public static void main(String[] args) D@1
^:'$V  
{ ScmzbDu  
new TestMethod(); D'hr\C^  
} z8[|LF-dx  
} h] TVi$J  
点击下载更多相关资料