http断点续传简单实现（java)

/* X E|B)Q(  
**SiteFileFetch.java vQ:wW',i  
*/ >i "qMZ  
package NetFox; 7~_I=-  
import java.io.*; Kv(z4z  
import java.net.*; *~p(GC  
:e*DTVv8  
8b|OXWl  
public class SiteFileFetch extends Thread { u!Xb?:3uj  
T~BA)![  
YT>KJ  
SiteInfoBean siteInfoBean = null; //文件信息Bean )
4l>XlQ&  
long[] nStartPos; //开始位置 '|A|vCRCG  
long[] nEndPos; //结束位置 TG}d3ZU !  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %$@1FlqX;  
long nFileLength; //文件长度 j'K38@M:MN  
boolean bFirst = true; //是否第一次取文件 F{<5aLaYti  
boolean bStop = false; //停止标志 -?s&pK
i  
File tmpFile; //文件下载的临时信息 I>PZYh'.T  
DataOutputStream output; //输出到文件的输出流 kv6Cp0uFg  
>F1G!#$0  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *G9sy_  
public SiteFileFetch(SiteInfoBean bean) throws IOException xwRhs!`t1  
{ 7A5p["?Z  
siteInfoBean = bean; U-i.(UyZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vT|`%~Be  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); HPrq1QpK  
if(tmpFile.exists ()) !8sgq{
x((  
{ HPg3`Ul  
bFirst = false; 8S\RN&T$  
read_nPos(); oM!xz1kVL  
} :.kZR;  
else 0}{'C5  
{ 7 8Vcu'j&_  
nStartPos = new long[bean.getNSplitter()]; hi ~}  
nEndPos = new long[bean.getNSplitter()]; S,)d(g3>  
} k1)%.pt%  
? B@&#E!/f  
cHx%Nd\  
JK]R*!{n  
} h.)h@$d  
&(EHq  
-KH)J  
public void run() T*?s@$)m4  
{ V A<5uk04K  
//获得文件长度 ?38lHn`FyQ  
//分割文件 X'f.Q  
//实例FileSplitterFetch z-dFDtiA  
//启动FileSplitterFetch线程 QT! 4[,4  
//等待子线程返回 A4.4Dji,x  
try{ O*[{z)M.  
if(bFirst) _]b3,%2  
{ `s|]"'rX  
nFileLength = getFileSize(); L*h{'<Bz  
if(nFileLength == -1) [}OgSP9i  
{ :_ROJ  
System.err.println("File Length is not known!"); %f j+70  
} rYY$wA@  
else if(nFileLength == -2) LCs__.  
{ $Az^Y0[D  
System.err.println("File is not access!"); 'fx UV<K&  
} 9i5tVOhE  
else ]5}=^  
{ 8S]".  
for(int i=0;i<nStartPos.length;i++) (hB?  
{ o!OMm!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Yw'NX5#)g  
} ).5RPAP  
for(int i=0;i<nEndPos.length-1;i++) Df4+^B,1  
{ 5!I4
l1  
nEndPos = nStartPos[i+1]; Q8D&tJg  
} 8'Z:ydj^,  
nEndPos[nEndPos.length-1] = nFileLength; ]0c+/ \b&  
} iDoDwq!l_  
} #*9-d/K  
?YQPlv:<o.  
a,|?5j9,P  
//启动子线程 :XG;ru%i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3*ixlO:qGk  
for(int i=0;i<nStartPos.length;i++) [kV;[c}  
{  foRD{Hx  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Os&n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Su8|R"qU  
nStartPos,nEndPos,i); \25/$Ae}c  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {sVY`}p|  
fileSplitterFetch.start(); 6Wj^*L!  
} &Lm-()wb  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
iD`d99f8O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l[Q:}y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lDc-W =X=  
nEndPos = " + nFileLength); 2 PqS%`XiS  
// fileSplitterFetch[nPos.length-1].start(); :s={[KBP  
1PH:\0}  
g7\,{Bw#E  
//等待子线程结束 gU&%J4O  
//int count = 0; 5%zXAQD=<  
//是否结束while循环 r%@Lej5+  
boolean breakWhile = false; \f:z+F!6R  
P 1XK*GZ  
m<rhIq  
while(!bStop) m2~&#c\  
{ Wy .IcWK  
write_nPos(); 5cJ!"  
Utility.sleep(500); 0NDftcB]  
breakWhile = true; *
\}}Bv+9  
mLh kI!4[  
dS2
G}L^L  
for(int i=0;i<nStartPos.length;i++) hR#-u1C  
{ p;T{i._iL  
if(!fileSplitterFetch.bDownOver) h!rM^  
{ +Y"r71|A6+  
breakWhile = false; q h/F  
break; }`(N:p  
} fq )vK  
} ;-P)
m  
if(breakWhile) ({r*=wAP  
break; #LlUxHv #  
<%.5hCTp97  
VKp*9%9  
//count++;  hc#!Lv  
//if(count>4) vhbDb)J  
// siteStop(); O.aG[wm8  
} kOOGw:/  
-l~Z0U>^  
Vj<:GRNQ,d  
System.err.println("文件下载结束！"); e^p +1-B  
} N|N3x7=gs  
catch(Exception e){e.printStackTrace ();} 5r~#0Zf*  
} 5 @U<I  
c'uhK8|  
Hy.AyU|L  
//获得文件长度 ho8`sh>N  
public long getFileSize() l^GP3S  
{ f()FY<b  
int nFileLength = -1; $`ZzvZ'r  
try{ K 0gI):  
URL url = new URL(siteInfoBean.getSSiteURL()); z>sbr<doa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~5Pb&+<$  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6E(Qx~iL  
w(ln5q  
<q*oV  
int responseCode=httpConnection.getResponseCode(); dr)YzOvba  
if(responseCode>=400) 6+r$t#  
{ n0Y+b[+wj  
processErrorCode(responseCode); _Zk{!  
return -2; //-2 represent access is error $mf u:tbP  
} ,.eWQK~  
FZjHw_pP  
lC:k7<0Ji  
String sHeader; [Wd-Zn%  
]Chj T}  
rX_@Ihv'  
for(int i=1;;i++) X%z }VA  
{ valtev0<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L,y6^J!  
//Utility.log(in.readLine()); #^m0aB7r  
sHeader=httpConnection.getHeaderFieldKey(i); Lg8nj< TF  
if(sHeader!=null) zp\8_U@  
{ #/PAA  
if(sHeader.equals("Content-Length")) DPi_O{W>  
{ 5T sUQc  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J+rC
xn?;g  
break; V5+SWXZ  
} HhO".GA  
} A-:O`RK  
else %ZHP2j %~  
break; oFjIA!  
} n>@oBG)!  
} W3`>8v1?o  
catch(IOException e){e.printStackTrace ();} pv|Pm  
catch(Exception e){e.printStackTrace ();} f{SB1M   
@`\VBW  
6'\6OsH  
Utility.log(nFileLength); dJ"iEb|4  
hW{j\@R  
&zs'/xv]  
return nFileLength; DNGvpKY@  
} ~y=T5wt  
LYlDc;<A  
UK9@oCIB  
//保存下载信息（文件指针位置） Gy=B&boZ  
private void write_nPos() G)?9.t_Lj-  
{ 8~5cJPi6  
try{ j ";2o(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hiNEJ_f  
output.writeInt(nStartPos.length); 2]%h$f+  
for(int i=0;i<nStartPos.length;i++) gZ5[ C  
{ >0Q|nCx  
// output.writeLong(nPos); xf|mlHS+  
output.writeLong(fileSplitterFetch.nStartPos); 1lv2@QH9  
output.writeLong(fileSplitterFetch.nEndPos); MZmb`%BZ  
} d)~Fmi;  
output.close();
Da"j E  
} <n3!{w3<  
catch(IOException e){e.printStackTrace ();} C6rg<tCH  
catch(Exception e){e.printStackTrace ();} NcY608C  
} B"%{i-v>**  
@?h/B=56  
6uKTGc4  
//读取保存的下载信息（文件指针位置） &89oO@5  
private void read_nPos() 0uBl>A7qhn  
{
wEzKqD  
try{ i<pk6rO1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mKYeD%Pm*  
int nCount = input.readInt(); eh"3NRrN  
nStartPos = new long[nCount]; |_ua
S  
nEndPos = new long[nCount]; *)+ut(x|#  
for(int i=0;i<nStartPos.length;i++) Z@hD(MS(C  
{
m&
|`x  
nStartPos = input.readLong(); 7FRmx4(!  
nEndPos = input.readLong(); II
q1\khh  
} ;5@ t[r  
input.close(); &+G"k~%  
} qKJSj   
catch(IOException e){e.printStackTrace ();} =y=cW1TG  
catch(Exception e){e.printStackTrace ();} }NsUnbxT  
} =J1rlnaaEL  
#-h\.#s  
CKA;.sh  
private void processErrorCode(int nErrorCode) ^e+
a  
{ fxgr`nC  
System.err.println("Error Code : " + nErrorCode); mFHH515  
} 4DTzSy:x  
O]qU[y+  
ek&kv#G  
//停止文件下载 [Y`,qB<B  
public void siteStop() $+7`Dy!  
{ 86z]<
p (  
bStop = true; 6Zn @2PGEl  
for(int i=0;i<nStartPos.length;i++) 4b:s<$TZ  
fileSplitterFetch.splitterStop(); vf8\i-U=  
_'#x^D  
Y@ZaJ@%9@  
} xU%w=0z<  
} E= `6-H{  
//负责部分文件的抓取 1T:Y0  
**FileSplitterFetch.java je]}R>[r5  
*/ iDf,e Kk$'  
package NetFox; u :F~K  
O@YTAT&d#  
Z{H5oUk  
import java.io.*; 5O`dO9g}$  
import java.net.*; Hk|0HL  
$-On~u0g  
s@fTj$h  
public class FileSplitterFetch extends Thread { Wa?; ^T  
Yq/.-4y  
 YBnA+l*  
String sURL; //File URL 'g9"Qv?0{`  
long nStartPos; //File Snippet Start Position [V}S<Xp  
long nEndPos; //File Snippet End Position zq%D/H6J,  
int nThreadID; //Thread's ID frBX{L  
boolean bDownOver = false; //Downing is over !Kv@\4  
boolean bStop = false; //Stop identical &7_Qd4=08w  
FileAccessI fileAccessI = null; //File Access interface Ja ,Cvt  
_!|/ ;Nk  
pJ ?~fp  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S/ibb&  
{ Rar"B
*b;$  
this.sURL = sURL; 7==f\%,  
this.nStartPos = nStart; N~F RM& x  
this.nEndPos = nEnd; H)(:8~c,p  
nThreadID = id;
;>mCalwj  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2}W0 F2*  
} mg,j
:,  
8#Q$zLK42N  
1 `KN]Nt  
public void run() D0BI5q  
{ 5y?-fT]X  
while(nStartPos < nEndPos && !bStop) Q3"}Hl2  
{ CA +uKM^"6  
rm} R>4  
$U/YR&vcw  
try{ kHqztg  
URL url = new URL(sURL); %e@#uxm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); It75R}B  
httpConnection.setRequestProperty("User-Agent","NetFox"); !\g
+8>  
String sProperty = "bytes="+nStartPos+"-"; Zc?ppO  
httpConnection.setRequestProperty("RANGE",sProperty); ox ;  
Utility.log(sProperty); 3 zn W=  
Ve 4u+0  
)Jv[xY~  
InputStream input = httpConnection.getInputStream(); 1LJUr"6]  
//logResponseHead(httpConnection); {?`al5Sz  
mJM_2Ab  
B7z -7&TE  
byte[] b = new byte[1024]; ,()0'h}n  
int nRead; y1/o^d+@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b?eu jxqg  
{ _A0w[n  
nStartPos += fileAccessI.write(b,0,nRead); ]@Sj`J[fd  
//if(nThreadID == 1) y7
^{yS[,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  kQ  
} `ImE% r!  
'fL"txW  
5MS
B dO  
Utility.log("Thread " + nThreadID + " is over!"); XbQlHfrS  
bDownOver = true; FW.$5*f='  
//nPos = fileAccessI.write (b,0,nRead); EJ`T$JD  
} x=#VX\5k:  
catch(Exception e){e.printStackTrace ();} D?Ux[Ozb  
} K'h1szW  
} Xj*vh m%i  
U!m@DJj  
n k2om$nN  
//打印回应的头信息 4GB7A]^E  
public void logResponseHead(HttpURLConnection con) 5?Wto4j  
{ gI8Bx]  
for(int i=1;;i++) tbO H#|  
{ [7YP
l9  
String header=con.getHeaderFieldKey(i); IMk'#)  
if(header!=null) ,[A'tUl _  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); CwX Z  
Utility.log(header+" : "+con.getHeaderField(header)); v|E"[P2e  
else 'u` .P:u?  
break; {%#)5l
)  
} 7G)H.L)$m"  
} 8KH\`
5<  
$\k0Nup}  
=rR~`  
public void splitterStop() ZR\VCVH\^  
{ 21(p|`X  
bStop = true; #);[mW{F  
} &[hLzlrg  
vp(;W,ba:|  
#b7$TV  
} wR{'y)$  
=
f(cH152T  
V _c@b%  
/* W14Vm(`N  
**FileAccess.java jg&E94}+  
*//文件访问(定位，写) c`fG1s  
package NetFox; aTzjm`F0  
import java.io.*; q:<{% U$  
N D<HXO  
b$eXFi/  
public class FileAccessI implements Serializable{ I7&_Xr  
e${>#>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #Mg]GeDJ{  
RandomAccessFile oSavedFile; &gI~LP  
long nPos; Ssk}e=]  
V i&*&"q  
7$rjlVe  
public FileAccessI() throws IOException 3<F </  
{ )(7&X45,k  
this("",0); 7r{83_B  
} j w* IO  
VACiVKk  
+1~Z#^{&  
public FileAccessI(String sName,long nPos) throws IOException K\)Td+~jc  
{ kg`.[{k  
oSavedFile = new RandomAccessFile(sName,"rw"); >Yt/]ta4+  
this.nPos = nPos; iKas/8  
oSavedFile.seek(nPos); phE &7*!Q  
} FW"^99mrnb  
"6a8s;  
W(hM
ft%  
public synchronized int write(byte[] b,int nStart,int nLen) z]3 `*/B  
{ %_
UN<a  
int n = -1; ,|88r=}  
try{ Z`&4SH=j  
oSavedFile.write(b,nStart,nLen); X w.p  
n = nLen; iVfgDo  
} L}m8AAkP[  
catch(IOException e) pZyQY+O  
{ Jl "mL  
e.printStackTrace (); n8hRaNHl2  
} Zatf9yGD  
qT/Do?Y  
?b!Fa  
return n; <|?K%FP7Z  
} dCu'>G\bP  
_uc\ D R  
ip~$X2  
} KgW:@X7wvM  
"KJ%|pg_C  
?6!]Nl1gr  
/* dSCzx .c  
**SiteInfoBean.java }oJAB1'k  
*/ VB<Jf'NU  
package NetFox; {_U Kttp  
I-ag
Zag%  
OTZ_c1
"K  
public class SiteInfoBean { 1T)Zh+?)}  
`m.eM  
)+H[kiN  
private String sSiteURL; //Site's URL y&_m4Zw"  
private String sFilePath; //Saved File's Path B??J@+Nf  
private String sFileName; //Saved File's Name _hG;.=sr  
private int nSplitter; //Count of Splited Downloading File r ]>\~&?^F  
R4Rb73o  
k-*Mzm]kb  
public SiteInfoBean() yFhB>i  
{//nSplitter的缺省值为5 e5Mln!.o  
//default value of nSplitter is 5 2 3KyCV5  
this("","","",5); A?Wk wf  
} \(p{t  
,_ag;pt
9)  
an2AX%u  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *4|Hqa  
{ -|Kzo_" v5  
sSiteURL= sURL; 8q)=  
sFilePath = sPath; h O emt  
sFileName = sName; ?GBkqQ  
this.nSplitter = nSpiltter; Z2"?&pKV  
U1_&gy @y  
6x=Y
Qwn~  
} a,7&"  
@/UfDye  
[\R>Xcu>  
public String getSSiteURL() x7T+>  
{ 6Fy@s  
return sSiteURL; Y\v-,xPm  
} @DC)]C2  
k n8N,,+  
m+itno  
public void setSSiteURL(String value) X bkb5EkA  
{ (Vg}Hh?p  
sSiteURL = value; Q)af|GW$  
} {0!#>["<  
OlD`uA  
E2B>b[  
public String getSFilePath() IF*&%pB  
{ ~:_0CKa!  
return sFilePath; YxJD_R  
} _{~]/k  
G%u9+XV1#  
8&V_$+U  
public void setSFilePath(String value) $\AEWFB  
{ nU`Lhh8y  
sFilePath = value; +CM7C%U   
} Lv1{k\aw  
#pdUJ2)yM  
W4YE~  
public String getSFileName() GD-&_6a  
{ }%{MPqg  
return sFileName; NN 0Q`r,8}  
} r+<{S\ Q  
si(;y](  
jw6Tj;c  
public void setSFileName(String value) O7aLlZdg~  
{ u1K\@jlw  
sFileName = value; ^Jp*B;  
} 0"[`>K~7a8  

/vE]2Io  
c#xP91.m  
public int getNSplitter() D&hqV)d4R  
{ K X]oE+:  
return nSplitter; }gf}eH  
} `Iy4=nVb  
p SN~DvR  
b~7drf
  
public void setNSplitter(int nCount) h7qBp300  
{ MEwdw3  
nSplitter = nCount; !F!3Q4  
} &S74mV  
} ZI ?W5ISdg  
6ew "fCrH!  
4}KU>9YRA  
/* n"aCt%v  
**Utility.java wX1ig  
*/ fMK#x\.4  
package NetFox; Hlj6$%.  
FquFRx  
Tvf~P w  
public class Utility { L*?!Z^k  
EY>8O+  
`{FwTZ=6{  
public Utility() Zzd/K^gg  
{ +lO'wa7|3  
igDyp0t  
nbdGt  
} EH`0  
UCqs}U8  
//线程睡眠 Gg0#H^s( (  
public static void sleep(int nSecond) 7el<5chZ  
{ X`20f1c6q>  
try{ |k-
XBp  
Thread.sleep(nSecond); VTe.M[:  
} S-E++f9D~  
catch(Exception e) 6 o[/F3`  
{ ,&a`d}g&G  
e.printStackTrace (); oJaAM|7uv  
} V"d=.Hb>  
} Pl~P-n  
Gm=>!.p  
//日志 J l7z|QS
 
public static void log(String sMsg) H)JS0 G0  
{ {sS_|sX  
System.err.println(sMsg); K^i"9D)A  
} T'rjh"C&|  
O25mkX  
%]Cjhs"v  
public static void log(int sMsg) @sf90&f  
{ <lFY7'aY  
System.err.println(sMsg); m7 XjP2  
} ~LE[, I:q  
} |ViU4&d*  
RLKj u;u  
~oi_r8K  
/* Rlc$;Z9K  
**TestMethod.java rpU/s@%L  
*/ v}il(w;O  
package NetFox; a[O6YgO  
cNP/<8dq  
>,g5Hkmqr  
public class TestMethod { kG3!(?:  
kHU"AD}.  
XNmQ?`.2'  
public TestMethod() jEU'.RBN%  
{ ///xx/weblogic60b2_win.exe \5[-Ml  
try{ Kd{#r/HZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \C\gn]Z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 
 8Uj:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <%,'$^'DS  
fileFetch.start(); ?6:cNdN  
} Y-&|VE2  
catch(Exception e){e.printStackTrace ();} 2lz {_9  
r>3^kL5UI  
Wu{&;$  
} =WRO\lgv.  
3hJH(ToO  
Dt {')  
public static void main(String[] args) Y. TYc;  
{ _bQL[eXd  
new TestMethod(); Oc-u=K,B  
} ze"~Ird  
} L[]^{ O
 
点击下载更多相关资料