http断点续传简单实现（java)

/* kkMChe};5  
**SiteFileFetch.java \D]9:BNJ  
*/ 3` D['  
package NetFox; \
!w |  
import java.io.*; zuFPG{^\#  
import java.net.*; qzO5p=}  
suFk<^3  
WIAukM8~  
public class SiteFileFetch extends Thread { k{hNv|:,  
BnDCK@+|Q  
""_G4{  
SiteInfoBean siteInfoBean = null; //文件信息Bean .yD 6$!6  
long[] nStartPos; //开始位置 l]Ym)QP  
long[] nEndPos; //结束位置 5j0 Ib>\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Fq oh!F  
long nFileLength; //文件长度 }s6Veosl  
boolean bFirst = true; //是否第一次取文件 |YV> #l  
boolean bStop = false; //停止标志 e"{"g[b/7  
File tmpFile; //文件下载的临时信息 {^:NII]  
DataOutputStream output; //输出到文件的输出流 EQw7(r|v:  
Di}M\!-[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F?cwIE\J  
public SiteFileFetch(SiteInfoBean bean) throws IOException =*zde0T?l  
{ Rh$+9w  
siteInfoBean = bean; y7rT[f/J  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s aHY9{)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); BgDWl{pm  
if(tmpFile.exists ()) x%[NK[^&  
{ hsYE&Np_Q  
bFirst = false; FgrVXb_q  
read_nPos(); Je2&7uR0  
} !#*#jixo  
else BpX`49  
{ fBz|-I:k +  
nStartPos = new long[bean.getNSplitter()]; @0C[o9  
nEndPos = new long[bean.getNSplitter()]; CPeu="[
 
} NpKyrXDJv  
H5 :,hrZY  
WU@_aw[  
c5 AaUza  
} o1*P|.`  
+9pock  
DnG9bVm>  
public void run() z}Us+>z+jc  
{ vifw
FPe  
//获得文件长度 ^Oeixi@f  
//分割文件 _6`GHx   
//实例FileSplitterFetch =VT\$ 5A  
//启动FileSplitterFetch线程 ![fNlG!r  
//等待子线程返回 #Ak|p#7 ^  
try{ 1wdc4>  
if(bFirst) ~Eb:AC5  
{ v<<ATs%w  
nFileLength = getFileSize(); _g( aO70Zu  
if(nFileLength == -1) wi+L4v  
{ Yo=$@~vN]  
System.err.println("File Length is not known!"); o~L(;A]yN  
} ("}C& 6)cB  
else if(nFileLength == -2) 9k6/D.Dz  
{ uqa pj("  
System.err.println("File is not access!"); BIew\N  
} V}7)>i$A  
else bhbTloCR  
{ %;= ?r*]  
for(int i=0;i<nStartPos.length;i++) 3;wiwN'  
{ wPu.hVz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); v;Q*0%~  
} ;(;~yB|NZ5  
for(int i=0;i<nEndPos.length-1;i++) TA:uB[Ji  
{ P/^@t+KC  
nEndPos = nStartPos[i+1]; UIg?3J}R  
} KsK]y,^Z  
nEndPos[nEndPos.length-1] = nFileLength; ;3xi.^=B  
} gy~2LY!}  
} 11Qi _T\  
pzUr9  
.X"&kO>G  
//启动子线程 I&gd"F _v}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b!Nr  
for(int i=0;i<nStartPos.length;i++) J7aYi]vI  
{ /me ]sOkn  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @p}_"BHYWt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %hw4IcWJ|  
nStartPos,nEndPos,i); KIR3m )  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LpSF*xm  
fileSplitterFetch.start(); }|N88PN  
} "!7Hu7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V"2 G
  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +RR6gAma}<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :RJo#ape  
nEndPos = " + nFileLength); j6$@vA)  
// fileSplitterFetch[nPos.length-1].start(); _3wK: T{:  
b`j9}tZ  
MLM/!N 7  
//等待子线程结束 $>uUn3hSx\  
//int count = 0; 4K dYiuz0`  
//是否结束while循环 >,'guaa  
boolean breakWhile = false; Y6hV ;[\F  
}Qe(6'l_  
{<gX~./]c  
while(!bStop) e{Vn{.i,5  
{ ,F`1VpTd8  
write_nPos(); Soe2Gq  
Utility.sleep(500); f7!48
,(fB  
breakWhile = true; % WXl*  
S1@r.z2L  
,aBy1K  
for(int i=0;i<nStartPos.length;i++) r&+C%  
{ 9(}d7y  
if(!fileSplitterFetch.bDownOver) IR:{{ (  
{ I@O9bxR?  
breakWhile = false; P?c V d2Y  
break; "rEfhzmyF  
} jq8TfJ|  
} 8fBhX,1  
if(breakWhile) #f_'&m  
break; h6<i,1gQ1  
w`+-xT%  
Hg8 4\fA  
//count++; <RbfW'<G  
//if(count>4) V?)V2>]  
// siteStop(); w9RBT(u  
} &+ PVY>q  
%H&WihQ  
=_g#I  
System.err.println("文件下载结束！"); ip
s)-1  
} p[At0Gc L  
catch(Exception e){e.printStackTrace ();} 
V EsM  
} D
d/]?4  
9n_RkW5g  
h05FR[</  
//获得文件长度 =ud~  
public long getFileSize() %hZX XpuO  
{ kq?:<!z  
int nFileLength = -1; G/fBeK$.  
try{ uV@'898%5  
URL url = new URL(siteInfoBean.getSSiteURL()); yD.(j*bMK;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Rbr:Q]zGN  
httpConnection.setRequestProperty("User-Agent","NetFox"); gi5X,:[  
m^m=/'<+  
*icaKy3  
int responseCode=httpConnection.getResponseCode(); n+Conp/  
if(responseCode>=400) 9mv0}I  
{ %{cVG-<_iz  
processErrorCode(responseCode); :V#xrH8R  
return -2; //-2 represent access is error omy3<6  
} iyr8*L\  
99By.+~pX  
O0`ofFN  
String sHeader; AFvv+ ss  
77aUuP7Iw  
n_LK8
 
for(int i=1;;i++) TvT>UBqj=  
{ 3B,dL|q(@J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~]?EV?T  
//Utility.log(in.readLine()); ,3MHZPJ?k]  
sHeader=httpConnection.getHeaderFieldKey(i); 6@FhDj2X  
if(sHeader!=null) On!+7is'  
{ 5`Uzxu  
if(sHeader.equals("Content-Length")) DKem;_6OQ  
{ jTV4iX  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); p}/D{|xO  
break; aUc#,t;Qd  
} "-MB 
U  
} 4^nHq 4_  
else (e!Yu#-  
break;
DcM/p8da  
} T\6,@7  
} .'38^  
catch(IOException e){e.printStackTrace ();} n<> ^cD  
catch(Exception e){e.printStackTrace ();} #DJZ42  
T<Qa`|5>  
&?5)Jis:  
Utility.log(nFileLength); B~qo^ppVU  
i!3*)-a\~`  
oAB:H\  
return nFileLength; Le bc@,  
} r)Zk-!1  
./0wt+  
AS~!YR  
//保存下载信息（文件指针位置） .HqJ)OH  
private void write_nPos() <ME>#,  
{ &sBD0R(a  
try{ opN4@a7l  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QLHEzEvf{/  
output.writeInt(nStartPos.length); Jc]66   
for(int i=0;i<nStartPos.length;i++) LN<rBF[_:f  
{ @W$ha y  
// output.writeLong(nPos); ~7g$TAe{  
output.writeLong(fileSplitterFetch.nStartPos); 8Exky^OT|  
output.writeLong(fileSplitterFetch.nEndPos); ?@FqlWz,  
} &OXx\}>MW  
output.close(); zzo93d  
} `ZM$\Q=:  
catch(IOException e){e.printStackTrace ();} $MNJsc^n  
catch(Exception e){e.printStackTrace ();} )Td{}vbIh  
} .v'`TD).6  
NYG!\u\Rm  
e 6>j gy  
//读取保存的下载信息（文件指针位置） ^*B@=  
private void read_nPos() gYk5}E-  
{ ;YMg4Cs  
try{ 3$5E1*ed  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?P>4H0@I+  
int nCount = input.readInt(); u#^l9/tl  
nStartPos = new long[nCount]; iPWr-  
nEndPos = new long[nCount]; w{*V8S3h9  
for(int i=0;i<nStartPos.length;i++) @o'L!5Y  
{ qIQ 61><  
nStartPos = input.readLong(); ~[
og\QZX  
nEndPos = input.readLong(); c9CFGo?)N  
} YTY(Et1i  
input.close(); jA^Dk$  
} IqsUtWSp  
catch(IOException e){e.printStackTrace ();} ;C:|m7|  
catch(Exception e){e.printStackTrace ();} 59W~bWHCP  
} Wc!]X.|9*  
HyKA+7}  
1n7'\esC*  
private void processErrorCode(int nErrorCode) 9Hb|$/FD  
{ {.KD#W $5  
System.err.println("Error Code : " + nErrorCode); P2C>IS  
} a;-%C{S9r  
I\c7V~^hnG  
QUvSeNSp  
//停止文件下载 g"Ueo'd*  
public void siteStop() c$BH`" <*  
{ HJym|G>%?  
bStop = true; Pi9?l>  
for(int i=0;i<nStartPos.length;i++)
XD0a :T)  
fileSplitterFetch.splitterStop(); P6ktA-Hv>  
LayK&RwL  
4(oU88z  
} e<a*@ P,  
} :&:P4Y1 E  
//负责部分文件的抓取 d]^m^
 
**FileSplitterFetch.java _~C1M&b(X3  
*/ $o\z4_I  
package NetFox; y&O?`"Uv/M  
G{>PYLxOb  
IEP|j;~*  
import java.io.*; 7gB?rJHV,  
import java.net.*; dKU:\y  
.8%b;b  
"X;5* 4+  
public class FileSplitterFetch extends Thread { [uHC AP  
oz,.gP%  
Buh}+n2]5  
String sURL; //File URL !]D`|HoW  
long nStartPos; //File Snippet Start Position UQ7]hX9  
long nEndPos; //File Snippet End Position BOcD?rrZ0  
int nThreadID; //Thread's ID -KfK~P3PF  
boolean bDownOver = false; //Downing is over R4JfH  
boolean bStop = false; //Stop identical ElDeXLr'  
FileAccessI fileAccessI = null; //File Access interface K\8zhY  
U:3OE97  
I_Gz~qk6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mD&I6F[s  
{ %eIaH!x:  
this.sURL = sURL; 74:~F)BP  
this.nStartPos = nStart; rKFnivGT  
this.nEndPos = nEnd; $M!i
Q"bb  
nThreadID = id; BKb#\(95*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $U9]v5  
} j3N d4#  
N|>JLZ>  
.QZjJ9pvK  
public void run() /BQqg08@L  
{ Umzb  
while(nStartPos < nEndPos && !bStop) #>,E"-]f  
{ 6aHD?a o  
-\;0gnf{J  
t0@AfO.'1  
try{ (U# Oj"  
URL url = new URL(sURL); 5p:BHw;%;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @|wU @by{  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4KR`  
String sProperty = "bytes="+nStartPos+"-"; #ley3rJW]  
httpConnection.setRequestProperty("RANGE",sProperty); !!V1#?0jw  
Utility.log(sProperty); -
Q JPJ.  
v7KBYN  
=H;'.!77Hx  
InputStream input = httpConnection.getInputStream(); *)
T"-}F  
//logResponseHead(httpConnection); p'%S{v@5((  
I=<Qpd4  
i '*!c  
byte[] b = new byte[1024]; n^hkH1vY  
int nRead; ">3t+A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1i~q~O,  
{ +lVA$]d  
nStartPos += fileAccessI.write(b,0,nRead); 'xG J;pY  
//if(nThreadID == 1) o 7tUv"Rs  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <rK[&JlJ  
} 4'*.3f'bp  
2PRiiL@  
>JsVIfAF
 
Utility.log("Thread " + nThreadID + " is over!"); FJCORa@?_  
bDownOver = true; 1;S?9N_B  
//nPos = fileAccessI.write (b,0,nRead); ~|O;Sdo=  
} 6m(? (6+;K  
catch(Exception e){e.printStackTrace ();} _,aFQ^]'9  
}
P!IA;i  
} ob2_=hQnC  
6D2ot&5WW  
TlkhI  
//打印回应的头信息 kp<Au)u  
public void logResponseHead(HttpURLConnection con) 2YY4 XHQS  
{ qpCaW0]7  
for(int i=1;;i++) EsX(<bx  
{ 32SkxcfrCK  
String header=con.getHeaderFieldKey(i); )AR-b8..o  
if(header!=null) ^gp]tAf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p3mZw lO  
Utility.log(header+" : "+con.getHeaderField(header)); {6RA~  
else _a& Z$2O  
break; Z8Y&
#cB  
} rCczQ71W  
} ,VEE<*'X  
ZX`x9/0&  
`5wiXsNjLY  
public void splitterStop() w6X:39d  
{ 4^:dmeMZ`  
bStop = true; -.MJ3  
} oi,KA  
 1hi,&h  
/}6y\3h  
} wL3RcXW``e  
G/#<d-}_  
[f lK  
/* $/g`{OI]K  
**FileAccess.java a.gMH uL  
*//文件访问(定位，写) 
ocK4Nxs  
package NetFox; s[h;9 I1w  
import java.io.*; ftPhE)i  
^lZ7%6  
tKLeq(  
public class FileAccessI implements Serializable{ MnF|'t  
2}/r>]9^-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 - ry  
RandomAccessFile oSavedFile; @d|Sv1d%  
long nPos; uE(5q!/  
 +@f  
_xi&%F/  
public FileAccessI() throws IOException j#P4&  
{ OAW_c.)5D  
this("",0); B]<N7NYn1  
} c U(z5th  
&K9RV4M5  
u1u;
aG  
public FileAccessI(String sName,long nPos) throws IOException q5EkAh<PD|  
{ SnXM`v,  
oSavedFile = new RandomAccessFile(sName,"rw"); >.od(Fh{l|  
this.nPos = nPos; CPcUB4a%#  
oSavedFile.seek(nPos); %@)q=*=y  
} ONcLhwH  
_eBNbO_J  
JLoE)\Mi  
public synchronized int write(byte[] b,int nStart,int nLen) R[v<mo[s  
{ L&:A59)1k  
int n = -1; Vraz}JV  
try{ Je9Z:s[  
oSavedFile.write(b,nStart,nLen); 2~g-k3  
n = nLen; F-ofR]|)>  
} 4f8XO"k7t=  
catch(IOException e) @g;DA)!(  
{ %++: K  
e.printStackTrace (); }93FWo.  
} eX"Ecl{  
z@\mn  
vShB26b  
return n; dQ-g\]d|  
} |P|2E~[r  
&Fuk+Cu{  
Zj ` ;IYFG  
} fB]2"(  
OiZ-y7;k^  
'@#(jY0_  
/* ~-lUS0duh  
**SiteInfoBean.java r^rk@W;[  
*/ p=x&X~  
package NetFox; !J<0.nO/:  
b 1Wz  
[] "bn9 +  
public class SiteInfoBean { )t-P o'RW  
_1$
Y
\Y  
yW7>5r  
private String sSiteURL; //Site's URL *,O3@,+>H  
private String sFilePath; //Saved File's Path 1)ij*L8k  
private String sFileName; //Saved File's Name tlvZy+Blv  
private int nSplitter; //Count of Splited Downloading File E2cZk6~m{  
ZK'WKC  
4s_5>r4  
public SiteInfoBean() ]K>bSK^TX  
{//nSplitter的缺省值为5 z%+rI  
//default value of nSplitter is 5 $/#[,1  
this("","","",5);  ;ud"1wH  
} b|kL*{;
  
`uusUw-Gf  
z+wegF  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2
MYez>D  
{ lAC"7 Z?F  
sSiteURL= sURL; j^U"GprA  
sFilePath = sPath; tIo
d=a)  
sFileName = sName; Zj ^e8u=T  
this.nSplitter = nSpiltter; ?^7X2 u$nm  
$w-@Oa*h9U  
7MJ\*+T|03  
} Ujvm|ml  
:cXN Fu\C  
X#ha*u~U  
public String getSSiteURL() *x p_#  
{ D[6sy`5l  
return sSiteURL; ".#h$  
} ~Cynw(  
e F}KOOfC  
;Q/1l=Bn  
public void setSSiteURL(String value) OR+py.vK  
{ kqo4 v;r  
sSiteURL = value; :2vuc!Pu  
} j8^#698X  
t*Z5{  
b~)
2
`l  
public String getSFilePath() E|_8#xvb  
{ c`lL&*]  
return sFilePath; /FPO'} 6i  
} Wk/Q~o  
sVmqx^-  
*u,&?fCl  
public void setSFilePath(String value) I7Abf7>*Q  
{ 5t_Dt<lIz  
sFilePath = value; 6iEg]FI  
} >nvK{6xR:  

JHZjf7g$k  
Sz1J4$5  
public String getSFileName() q?]KZ_a  
{ aAn p7\7  
return sFileName; MMD=4;X  
}
\xC#Zs[<  

.Xe_Gp"x  
368 g>/#'  
public void setSFileName(String value)
rqm":N8@  
{ 4:b'VHW.  
sFileName = value; @PQd6%@  
} tk8\,!
9Q  
L@Qvj-5e  
.i|nn[H &  
public int getNSplitter() <~_XT>`y  
{
z_{_wAuY  
return nSplitter; fF9hL3h?)  
} Vl<7>  
gCVOm-*:  
$cm9xW&  
public void setNSplitter(int nCount) F1M:"-bda  
{ .We{W{  
nSplitter = nCount; c_.Fe'E  
} psz0q|
 
} >$ro\/  
Qr6PkHU  
ZUz7h^3@  
/* C,LosAd  
**Utility.java NB.'>Sar  
*/ #67 7,dn  
package NetFox; [!uVo>Q4  
^1_[UG  
AqaMi  
public class Utility { ~>~qA0m"m  
f3>DmH#  
U.$Th_  
public Utility() # M!1W5#  
{ |}<Gz+E>  
AKk&  
HN5,MD[  
} qFq$a9w|@  
WoNY8 8hT  
//线程睡眠 2vsV:LS.  
public static void sleep(int nSecond) /?z3*x  
{ 9v8^uPA  
try{ #<u;.'R  
Thread.sleep(nSecond); Ra H1aS(  
} :l iDoGDi  
catch(Exception e) PqF&[M<)  
{ /J&DYxl":  
e.printStackTrace (); [9MbNJt 8~  
} 3Z#WAhfS:  
} ?*7
Mn`  
'^$+G0jv  
//日志 @^ m0>H  
public static void log(String sMsg) fd>&RbUp  
{ DrxQ(yo}  
System.err.println(sMsg); Q#K10*-O6  
} @A*>lUo  
*8)va  
gA@Zx%0j  
public static void log(int sMsg) 27$,D XD  
{ d/~g3n>|  
System.err.println(sMsg); u3tT=5.D  
} U)aftH *Pk  
} .|s,':hA  
 vP? T  
~gNFcJuy  
/* {0-rnSjC  
**TestMethod.java x)eoz2E1  
*/ MPw?HpM  
package NetFox; S3E5^n\\  
GCfVH?Vx  
3Z&!zSK^  
public class TestMethod { FC+h \  
#reW)P>  
@';.$  
public TestMethod() Aq3\Q>klH)  
{ ///xx/weblogic60b2_win.exe &Vgpv#&Cfx  
try{ g0B%3v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); G|8>Q3D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QgQ$>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Np ru  
fileFetch.start(); >'.: Acn  
} rzLW@k  
catch(Exception e){e.printStackTrace ();} zEukEA^9`  
N>]J$[j  
#k`gm)|  
} 8?YeaMIBB  
q(~|roKA(  
 jIH^  
public static void main(String[] args) jiLJiYMg  
{ "dvo@n|  
new TestMethod(); hCd? Kti  
} eR6vO5to  
} <yBa5m@/  
点击下载更多相关资料