http断点续传简单实现（java)

/* jj#K[@u  
**SiteFileFetch.java LZyUlz  
*/ oa+Rr&t'  
package NetFox; L^)&"6oSa  
import java.io.*; _ 9Tv*@  
import java.net.*; *;O$=PE  
;*+jCL2F  
VZJs@qx:Z  
public class SiteFileFetch extends Thread { |J2Rwf  
J(S.iTD  
CJ&0<Z}{m  
SiteInfoBean siteInfoBean = null; //文件信息Bean l.lXto.6)  
long[] nStartPos; //开始位置 V$-IRdb  
long[] nEndPos; //结束位置 )2z (l-$.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 VVvV]rU~  
long nFileLength; //文件长度 :M1S*"&:  
boolean bFirst = true; //是否第一次取文件 G6Z2[Ej1  
boolean bStop = false; //停止标志 eQno]$-\  
File tmpFile; //文件下载的临时信息 \no[>L]  
DataOutputStream output; //输出到文件的输出流 'rU [V
+  
$r9Sn  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1A">tgA1  
public SiteFileFetch(SiteInfoBean bean) throws IOException @Wy>4B^  
{ o8RagSIo8  
siteInfoBean = bean; '>Y"s|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vj^vzFbK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~jmHzFkQ  
if(tmpFile.exists ()) ld4QhZia  
{ bQb>S<PT  
bFirst = false; |Z$heYP:w  
read_nPos(); +%8c8]2  
} $)mE"4FE  
else s6w</  
{ Z6X?M&-Lz  
nStartPos = new long[bean.getNSplitter()]; veAGUE %3  
nEndPos = new long[bean.getNSplitter()]; 5Y"lr Y38  
} >"B95$x5  
oKiBnj5J  
(J][(=s;a  
wnP#.[,V  
} <Jo_f&&{  
c{6!}0Q4  
bJ]g2C7`36  
public void run() +o!".Hp  
{ )wo'i]#2:  
//获得文件长度 =g2;sM/  
//分割文件 b|wCR%  
//实例FileSplitterFetch "Nn/vid;  
//启动FileSplitterFetch线程 NHUx-IqOX  
//等待子线程返回 .#6Dad=S*  
try{ <u*~RYA2  
if(bFirst)  s6rdQI]  
{ r~z-l,  
nFileLength = getFileSize(); 1fm\5/}'`1  
if(nFileLength == -1) x;l\#x/<  
{ "ZNiTND  
System.err.println("File Length is not known!"); P(d4~hS  
} ^{_`jE  
else if(nFileLength == -2) <jQ?l%\  
{ 9@#Z6[=R,  
System.err.println("File is not access!"); ,;'9PsIS^  
} v}IkY  
else R>To L  
{ jtV{Lf3<  
for(int i=0;i<nStartPos.length;i++) j>+x|!k  
{ M&~3fRb4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z[yQKy  
} pN&5vu30  
for(int i=0;i<nEndPos.length-1;i++) &p^S6h  
{ N't*eCi  
nEndPos = nStartPos[i+1]; kz(%8qi8&  
} @U_w:Q<9u  
nEndPos[nEndPos.length-1] = nFileLength; kV(}45i]s  
} 9l@VxX68M  
} Lf&p2p?~c  
?0WJB[/  
<bWhTNOb  
//启动子线程 +n%uIv  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; m\__F
l  
for(int i=0;i<nStartPos.length;i++) ZTW
be  
{ '%yWz)P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s@E"EWp0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), X5cl'J(j9  
nStartPos,nEndPos,i); bBc<yaN  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0R>M_|  
fileSplitterFetch.start(); :Oo(w%BD]  
} /-b)`%Q|Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *T*=~Y4kE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Xa.Qt.C  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Gmi4ffIb3  
nEndPos = " + nFileLength); ``)ys^V  
// fileSplitterFetch[nPos.length-1].start(); j8$
*$|  
$U<so{xn%  
b-'41d}Hn  
//等待子线程结束 6n]fr9f  
//int count = 0; v9(->X'  
//是否结束while循环 4*g`!~)  
boolean breakWhile = false; H2l/9+  
~z$vF  
z/)HJo2#  
while(!bStop) (GJ)FWen0"  
{ wbshKkUh_*  
write_nPos(); YQvN;W  
Utility.sleep(500); y~w2^VN=  
breakWhile = true; w7$*J:{  
Q9H~B`\nQ  
D'F=v\P  
for(int i=0;i<nStartPos.length;i++) f ."bq43(  
{ Wjn1W;m&g  
if(!fileSplitterFetch.bDownOver) R"EX$Zj^E  
{ $-[V
)]h  
breakWhile = false; Q<3=s6@T  
break; XZLo*C!MG  
} @tWyc%t  
} cJd~UQ<k  
if(breakWhile) t8DySFT  
break; rn#FmM  
:3M2zV cf  
Q3vC^}Dmr  
//count++; 4d#w}  
//if(count>4) NJ^`vWi  
// siteStop(); {O9CYP:  
} [x ?38  
JziuwL5,  
Lg0Vn&k  
System.err.println("文件下载结束！"); tT'*Uu5  
} oMawINDa  
catch(Exception e){e.printStackTrace ();} 2F[smUL
 
} 1Y
:lFGoe  
 h%0/j  
3JVENn9  
//获得文件长度 T&c0j(  
public long getFileSize() O}I8P")m  
{ =T;>$&qs  
int nFileLength = -1; D0Yl?LU3  
try{ ^AkVmsv;;  
URL url = new URL(siteInfoBean.getSSiteURL()); 0)`{]&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "K n JUXpl  
httpConnection.setRequestProperty("User-Agent","NetFox"); HgPRz C  
kNP.0  
|7XSC,"  
int responseCode=httpConnection.getResponseCode(); h@}KBK  
if(responseCode>=400) {"$ Q'T  
{ dqMt6b\}  
processErrorCode(responseCode); yBqv'Y  
return -2; //-2 represent access is error P,r9<  
} y|f`sBMM  
aG.j0`)%  
7p%W)=v  
String sHeader; knrR%e;  
6FNs4|(
d  
++d(}^C;  
for(int i=1;;i++) x
db9oH  
{ wNMgY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Au
uZWd  
//Utility.log(in.readLine()); <7N8L  
sHeader=httpConnection.getHeaderFieldKey(i); qR^KvAEQSo  
if(sHeader!=null) \g<9_  
{ 1ThONrxu  
if(sHeader.equals("Content-Length")) GxE"q-G  
{ J0CEZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); fmyyQ|]O"  
break; ]L#6'|W  
} FjF:Eh  
} #va|&QBZxM  
else 35I y\  
break; vH/z|<  
} X_GR{z%  
} "9,z"k  
catch(IOException e){e.printStackTrace ();} /cHd&i,>  
catch(Exception e){e.printStackTrace ();} [lZo'o  
d MQ]=  
B7r={P!0  
Utility.log(nFileLength); [~03Z[_"/  
KdY3  
"S#4  
return nFileLength; ru[W?O"  
} 7zo)t1H1  
vH/<!jtI  
37GJ}%Qs  
//保存下载信息（文件指针位置） [5K&J-W  
private void write_nPos() $MD|YW5  
{ .J:04t1  
try{ kXimJL_<g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); e+jp03m\W  
output.writeInt(nStartPos.length); ~wG.'d]  
for(int i=0;i<nStartPos.length;i++) M,xhQ{eBY  
{ !R*%F  
// output.writeLong(nPos); i(R&Q;{E^  
output.writeLong(fileSplitterFetch.nStartPos); q] g'rO'  
output.writeLong(fileSplitterFetch.nEndPos); vJ5`:4n"  
} w#.Tp-AZ;\  
output.close(); \pI)tnu6'U  
} NX7(;02  
catch(IOException e){e.printStackTrace ();} w{uqy]  
catch(Exception e){e.printStackTrace ();} \l!^6G|c  
} \`?#V xz  
.3WDtVE  
pW ]+a0j  
//读取保存的下载信息（文件指针位置） P\<dy?nZ  
private void read_nPos() N2:};a[ui5  
{ `L p3snS  
try{ XQL"D)fw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #?%akQ
+w  
int nCount = input.readInt(); z d 9Gi5&  
nStartPos = new long[nCount]; @y:mj \J9  
nEndPos = new long[nCount]; %-ih$ZY  
for(int i=0;i<nStartPos.length;i++) l%"[857  
{ cx%[hM09  
nStartPos = input.readLong(); |O0=Q,<m  
nEndPos = input.readLong(); *?jU$&Qpj*  
} 46(Vq|  
input.close(); ~5Wr |qg%{  
} H|8vW  
catch(IOException e){e.printStackTrace ();} }p-<+sFo  
catch(Exception e){e.printStackTrace ();} mXZOkx{  
} @Dc?fyY*o<  

\2cbZQx  
jP'.a. ^o$  
private void processErrorCode(int nErrorCode) wI'8B{[  
{ yNp l0 d  
System.err.println("Error Code : " + nErrorCode); 3/a$oO
 
} ,VZ;=  
b;$ -s \%  
Ju5<wjQR\  
//停止文件下载 >C""T`5]  
public void siteStop() XVXiiQ^  
{ BLxtS  
bStop = true; gQy{OU  
for(int i=0;i<nStartPos.length;i++) x`N_tWZ  
fileSplitterFetch.splitterStop(); jR~2mf!h*e  
S"?py=7  
QuFcc}{<]  
} 'G1~\CT  
} nLK%5C  
//负责部分文件的抓取 jxA`RSY  
**FileSplitterFetch.java O8BxXa@5  
*/ :x e/7
-  
package NetFox; &sbA:xZBA  
(lv|-Phc.  
GCx1lm  
import java.io.*; Jp)>Wd  
import java.net.*; n]&/?6}  
ow:}NI  
{XYv&K  
public class FileSplitterFetch extends Thread { R_4]6{Rm  
s_Y1rD*B  
`jY*0{  
String sURL; //File URL :UjHP}s  
long nStartPos; //File Snippet Start Position PMr {BS  
long nEndPos; //File Snippet End Position S-^y;#=  
int nThreadID; //Thread's ID |RT#ZMJek  
boolean bDownOver = false; //Downing is over K{[ySB  
boolean bStop = false; //Stop identical dRg1I=|{_  
FileAccessI fileAccessI = null; //File Access interface 51.! S  
rAqg<fR*  
(1e;7sNG@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException + >o/Ob  
{ 1g`$[wp|  
this.sURL = sURL; i9}n\r0=c  
this.nStartPos = nStart; b~\gV_Z  
this.nEndPos = nEnd; zo66=vE!  
nThreadID = id; [uO
W\)`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,=KJ7zIK?  
} }N;c  
wc-H`S|@  
;p~@*c'E  
public void run() C[ <O
F/  
{ `o(PcX3/}  
while(nStartPos < nEndPos && !bStop) e9r#r~Qq|  
{ 2GRh8G&5  
EgIFi{q=0  
i|u3Qt5  
try{ .v[8ie  
URL url = new URL(sURL); Te?UQX7Z}M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b;\qF&T  
httpConnection.setRequestProperty("User-Agent","NetFox"); eK\ O>  
String sProperty = "bytes="+nStartPos+"-"; \ ?['pB  
httpConnection.setRequestProperty("RANGE",sProperty); (mXV5IM  
Utility.log(sProperty);
,2u-<8  
& i|x2; v  
4)Y=)#=  
InputStream input = httpConnection.getInputStream(); W2h^ShG  
//logResponseHead(httpConnection); 061@N=p8  
nIVPh99  
_$/(l4\T[  
byte[] b = new byte[1024]; k^gnOU;  
int nRead; Qz&I~7aoyV  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;;BQuG  
{ +s&+G![  
nStartPos += fileAccessI.write(b,0,nRead); w2y{3O"p=  
//if(nThreadID == 1) KfJF9!U*?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mMO:m8W  
} Cec!{]DL&  
YBQO]3f  
P(fTlrb  
Utility.log("Thread " + nThreadID + " is over!"); E@QsuS2&  
bDownOver = true; %w7J
0p  
//nPos = fileAccessI.write (b,0,nRead); &,Dh*)k  
} 30]?Jz6m  
catch(Exception e){e.printStackTrace ();} @V)k*h3r+  
} 6TS+z7S81L  
} ewB&PR  

%tM]|!yw  
H@2JL.(k  
//打印回应的头信息 /Kb7#uq  
public void logResponseHead(HttpURLConnection con) SFKW"cP  
{ Z[KXDQn8  
for(int i=1;;i++) B&|F9Z6D  
{ y|V/xm+Fp  
String header=con.getHeaderFieldKey(i); ;<0Q<0G  
if(header!=null) bnLvJ]i)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &k(t_~m>  
Utility.log(header+" : "+con.getHeaderField(header)); sJtz{'  
else VkFTIyt  
break; Lu}oC
2
  
} @u3K.}i:g  
} |0n h  
/HH5Mn*  
(qHI>3tpY  
public void splitterStop() T#?KY  
{ {y=H49  
bStop = true; oz%ZEi\bW  
} "XMTj <D  
N8:?Z#z  
nU%rSASu  
} oH!sJ&"#_  
4W}8?&T  
4%2QF F@  
/* (.7_`T6QG  
**FileAccess.java 9ET2uDZpL  
*//文件访问(定位，写) <QTu"i  
package NetFox; ,6PV"E)_  
import java.io.*; YTxUKE:  
ORlz1&hW  
ftF?T.dx  
public class FileAccessI implements Serializable{ OM{-^  
By6C+)up  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 orf21N+[  
RandomAccessFile oSavedFile; MGX %U6  
long nPos; K97lP~Hu  
z.oDH<1
 
?qYw9XQYL  
public FileAccessI() throws IOException 1t=Y+|vA9  
{
(:].?o  
this("",0); bG67TWY)  
} ?I)-ez  
~|@aV:k  
gt6*x=RCrQ  
public FileAccessI(String sName,long nPos) throws IOException |ap{+ xh  
{ uF9p:FvN8  
oSavedFile = new RandomAccessFile(sName,"rw"); 8e)k5[\m  
this.nPos = nPos; [ivz/r(Rj  
oSavedFile.seek(nPos); @^} % o-:  
} ,7SLc+  
d|]F^DDuI  
ukv _bw  
public synchronized int write(byte[] b,int nStart,int nLen) ?/)Mt(p  
{ :h0as!2@dp  
int n = -1; v>.nL(VLjP  
try{ cEi{+rfZd|  
oSavedFile.write(b,nStart,nLen); |gx{un`  
n = nLen; l/[@1(F  
} JT&CJ&#[h  
catch(IOException e) :1eI"])(  
{ 6#6Ve$Vl]  
e.printStackTrace (); akgXI^K  
} (qlIQC  
Q[scmP^$^  
Df02#493  
return n; zC!]bWsD  
} l@4hBq  
8^&)A b  
~el#pf~  
} wKe^5|Rr  
j[m\;3Sp  
!tv3.:eT  
/* <<LmO-92  
**SiteInfoBean.java n_AW0i.  
*/ yEtI5Qk  
package NetFox; r^_8y8&l  
HD?z  
AvRZf-Geg  
public class SiteInfoBean { Crh5^?  
~ygiKsD6b  
[=u8$5/a  
private String sSiteURL; //Site's URL Q#urx^aw  
private String sFilePath; //Saved File's Path 2V/A%  
private String sFileName; //Saved File's Name ;gy_Qf2U  
private int nSplitter; //Count of Splited Downloading File .}kUD]pW  
 kOETx  
>#*]/t  
public SiteInfoBean() yfiRMN"2  
{//nSplitter的缺省值为5 NS-u,5Jt  
//default value of nSplitter is 5 U
d^+a H  
this("","","",5); {z|0Y&>[=  
} 2W|4
 
}fZT$'*;  
})g|r9=  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yopEqO  
{ FoWE<  
sSiteURL= sURL; Thn-8DT  
sFilePath = sPath; ^=bJ _'  
sFileName = sName; huWUd)Po%  
this.nSplitter = nSpiltter;  /8Bh  
g10$pf+L  
99G/(Z}  
} Df||#u=n  
m/=,O_  
8<0H(lj7_  
public String getSSiteURL() E,shTh%&~  
{ \yNjsG@,  
return sSiteURL; I?J$";A  
} m
l.l( 6A  
fU!C:  
T5B~CC'6  
public void setSSiteURL(String value) I|m fr{  
{
.sAcnf"  
sSiteURL = value; qnyFRPC  
} Se*ZQtwE  
ipjl[  
LT!.M m  
public String getSFilePath() -5>K pgXo\  
{ H&[CSc  
return sFilePath; &.an-  
} )AXTi4MNp  
;T/W7=4CZ  
.=3Sm%  
public void setSFilePath(String value) K7M7T5<  
{ U&C\5N]  
sFilePath = value; ^>h
9<  
} =R:3J"ly0  
'1~mnmiP  
0fxA*]h  
public String getSFileName()  ?Vbe  
{ 9Vxsv*OR,  
return sFileName; $.R$I&U  
} r&A#h;EQX2  
3lMmSKN  
g v&xC 6>  
public void setSFileName(String value) rs~RKTv-  
{ fxI>FhU_  
sFileName = value; ]]d9\fw  
} D}HW7Hnu^  
d~g  
[Rs5hO  
public int getNSplitter() j8M}
*1  
{ %g5weiFM  
return nSplitter; E+dr\Xhv  
} DvF`KHsy  
.r[DqC  
szF[LRb  
public void setNSplitter(int nCount) %.pX!jL  
{ Z7JI4"  
nSplitter = nCount; +NxEx/{  
} ?%{bMqYJD{  
} igOjlg_Q  
L

=Dd`  
5Jp@n .  
/* {ogGi/8  
**Utility.java VHM,W]  
*/ |n=m8X  
package NetFox; ]Q-ON&/  
B*zb0hdo:  
{}D8Y_=9\  
public class Utility { Q6_!I42Y`  
ul(1)q^  
Up`$U~%-  
public Utility() 8n?P'iM  
{ 6>%)qc$i  
g4=}].  
0jrcXN~  
} #i7!  
m qPWCFP  
//线程睡眠 8{6KWqG\  
public static void sleep(int nSecond) *P$5k1  
{ K~
+y<z E  
try{ -/~^S]  
Thread.sleep(nSecond); FGr0W|?v  
} fH`P8?](x  
catch(Exception e) "#rlL^9v  
{ S!#7]wtbP  
e.printStackTrace (); ?%JH4I2  
} qK:
.j  
} +@cf@}W6QC  

X@JDfn?A  
//日志 Fw!5hR`,  
public static void log(String sMsg) |LcN_,}6  
{ cwz %LKh  
System.err.println(sMsg); KB&t31aq  
} @>qzRo  
Pgr>qcbql  
\hc}xy 0  
public static void log(int sMsg) JR$Dp&]I  
{ /!eC;qp;[  
System.err.println(sMsg); {3$ge  
} C&NoEtL>s  
} 59$mfW o>  
7_E+y$i=  
6^mO<nB   
/* NqkRR$O  
**TestMethod.java ?qHW"0Tjn  
*/ gD
_tBv  
package NetFox; lk}R#n$  
'iXjt MX  
Mn7 y@/1  
public class TestMethod { wI #_r_  
}qc[ysDK]  
H 
}uT'  
public TestMethod() W2%(a0p  
{ ///xx/weblogic60b2_win.exe Z&s+*&TM  
try{ ;T"}dJel#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _Y|k \|'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4oT25VH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zXbTpm  
fileFetch.start(); vo!:uvy;2  
} dB<BEe\$g.  
catch(Exception e){e.printStackTrace ();} ZA1?'  
, y{o!w  
_S,2j_R9  
} \&2GLBKpe  
;
#EB0TK  
cw/g1,p  
public static void main(String[] args) V>gEF'g  
{ 3yr{B Xn  
new TestMethod(); uEVRk9nb  
} AjAmV hq  
} zST#X}  
点击下载更多相关资料