http断点续传简单实现（java)

/* gO*:<B g  
**SiteFileFetch.java )P:r;a'  
*/ yub|  
package NetFox; |kwBb>V  
import java.io.*; $2uZdl8Rvj  
import java.net.*; 4J=6A4O5Z  
uqy b  
7tOOruiC  
public class SiteFileFetch extends Thread { W+[XNIg5   
(U"Ub;[7  
tZS-e6*S  
SiteInfoBean siteInfoBean = null; //文件信息Bean HS{a^c%  
long[] nStartPos; //开始位置 E,I*E{nd9  
long[] nEndPos; //结束位置 Q:I2\E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~f&lQN'1  
long nFileLength; //文件长度 4\)
"Ih  
boolean bFirst = true; //是否第一次取文件 0f.rjd  
boolean bStop = false; //停止标志 yUb$EMo\  
File tmpFile; //文件下载的临时信息 xjHOrr OQ  
DataOutputStream output; //输出到文件的输出流 v:*t5M >  
/5^"n4/M  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }]1=?:tX%  
public SiteFileFetch(SiteInfoBean bean) throws IOException c+PT"/3
  
{ kG:,Ff>  
siteInfoBean = bean; =%,;=4w  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _qg)^M6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SG1o<#>  
if(tmpFile.exists ()) 6Q<^,`/T  
{ aa8xo5tIp  
bFirst = false; r<]Db&k   
read_nPos(); YNc
]x>  
} YqsN#E3pf  
else [
h "*>J{  
{ OhmKjY/}  
nStartPos = new long[bean.getNSplitter()]; uT8@p8  
nEndPos = new long[bean.getNSplitter()]; Kq}/`P  
} n:zoN2lC  
S<
"M5e  
Z%3]  
vn"2"hPF|  
} ZMmaM "9  
=M"H~;f]  
t^0^He$Ot  
public void run() 7cx~?xk <m  
{ NET?Ep  
//获得文件长度 1JIL6w_  
//分割文件 k=,,s(]tx  
//实例FileSplitterFetch ZV}"k_+-  
//启动FileSplitterFetch线程 BIf E+
L(  
//等待子线程返回 s`* 'JM<  
try{ VeO$n*O  
if(bFirst) cstSLXD  
{ v.,|#}0 o  
nFileLength = getFileSize(); $:M*$r^u  
if(nFileLength == -1) av>c  
{ 
#L}YZ  
System.err.println("File Length is not known!"); 6AeX$>k+  
} |;2Y|>=  
else if(nFileLength == -2)
L(a&,cdh  
{ (4_7ICFI  
System.err.println("File is not access!"); aEr<(x!|"  
} 4`lt 4L  
else UW7*,Bq  
{ 1PWs">*(  
for(int i=0;i<nStartPos.length;i++) ~[|&)}q  
{ yX%T-/XJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8Xpf|?.  
} y6.}h9~  
for(int i=0;i<nEndPos.length-1;i++) 7Iu^l4=2  
{ ,Y&LlB 2  
nEndPos = nStartPos[i+1]; Y1a[HF^-  
} 9"Vch;U$  
nEndPos[nEndPos.length-1] = nFileLength; nU]n]gd  
} K*;e>{p  
} a1Q|su{H  
;V(- ;O  
mG4myQ?$  
//启动子线程 bJc<FL<E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Df;EemCh  
for(int i=0;i<nStartPos.length;i++) {awv=s  
{ 4\'1j|nS[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zbHNj(~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3nb&Z_/e  
nStartPos,nEndPos,i); yl
|?+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y,{=*2Yt  
fileSplitterFetch.start(); :3`6P:^  
} ?E1<>4S8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OiI[w8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Kx.'^y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~(E.$y7P  
nEndPos = " + nFileLength); yZup4#>8  
// fileSplitterFetch[nPos.length-1].start(); ,ra!O=d~0  
\_?A8
F  
^LfN6{  
//等待子线程结束 r':wq
 
//int count = 0; aRSGI ja<L  
//是否结束while循环 r*#ApM"L  
boolean breakWhile = false; ^z&eD,  
@Qw~z0PE<l  
R`}C/'Ty  
while(!bStop) -#0(Jm'  
{ eF]`?AeWQ  
write_nPos(); .FUws  
Utility.sleep(500); @tQu3Rq@  
breakWhile = true; qYD$_a  
6H+'ezM  
r!H'8O!  
for(int i=0;i<nStartPos.length;i++) l1(6*+  
{ 7!%/vO0m  
if(!fileSplitterFetch.bDownOver) RLBeti>  
{ yW::`  
breakWhile = false; DONXq]f:,"  
break; 12 y=Eh  
} p,_,o3@~  
} WZz8VF  
if(breakWhile) USF9sF0l  
break; )8`7i{F  
L$R"?O7  
K9{3,!1  
//count++; cd_\?7  
//if(count>4) a]0B{  
// siteStop(); pq8XCOllXx  
} U^qQ((ek  
VaYL#\;c<  
HEqTlnxUu  
System.err.println("文件下载结束！"); )`,||sQ  
} c6v@6jzx0Y  
catch(Exception e){e.printStackTrace ();} xJCMxt2Y  
} "*08?KA  
71euRIW'5  
MW^(  
//获得文件长度 zKRt\;PW  
public long getFileSize() Fjnp0:p9X  
{ QaAA@l  
int nFileLength = -1; 4:umD*d 3E  
try{ @zu IR0Gr)  
URL url = new URL(siteInfoBean.getSSiteURL()); b2L9%8h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Vq8G( <77  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ej_>*^b  
k2bjBAT  
O}#Ic$38  
int responseCode=httpConnection.getResponseCode(); n~c<[  
if(responseCode>=400) /l.:GH36f  
{ SB1j$6]OR7  
processErrorCode(responseCode); AN193o   
return -2; //-2 represent access is error G909R
>  
} *R'r=C`  
^)J2tpr;]=  
}I}/e v  
String sHeader; [j3-a4Wu  
QR+xPY~  
9Wu c1#  
for(int i=1;;i++) $7bLw)7  
{ Cs:?9G  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s=S9y7i(R  
//Utility.log(in.readLine()); <bSG|VqnH  
sHeader=httpConnection.getHeaderFieldKey(i); i2+r#Hw#5R  
if(sHeader!=null) wDQ@$T^vh  
{ $ol]G`+  
if(sHeader.equals("Content-Length")) t4;eabZK  
{ }nEa9h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %>p[;>jW  
break; bA_/6r)u  
} \T'.b93~B  
} <wH"{G3?  
else YYE{zU  
break; x/fhlf}a}=  
} V),wDyi  
} M2kvj'WWq  
catch(IOException e){e.printStackTrace ();} D%`O.2T Y|  
catch(Exception e){e.printStackTrace ();} PFKl6_(  
X!b+Dk  
AX%N:)_$|  
Utility.log(nFileLength); lGlh/B%  
%K`th&331  
L[s`8u<_)z  
return nFileLength; 4Wd H!z  
} $+k|\+iJ  
B_uhNLd  
uGmv`R_  
//保存下载信息（文件指针位置） -Qy@-s $  
private void write_nPos() 5gq  
{ &ir|2"HV  
try{ SeV`RUO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3jqV/w[-  
output.writeInt(nStartPos.length); tP:ER  
for(int i=0;i<nStartPos.length;i++) dc dVB>D  
{ l\/uXP?  
// output.writeLong(nPos); D03QisH=  
output.writeLong(fileSplitterFetch.nStartPos); 1!%T<!A.  
output.writeLong(fileSplitterFetch.nEndPos); d[\$a4G+  
} z"D0Th`S6  
output.close(); WK.K-bd  
} { v [  
catch(IOException e){e.printStackTrace ();} 1`sTGNo  
catch(Exception e){e.printStackTrace ();} !gm@QO cF  
} OcE,E6LD  
!C;$5(k  
hAV@/oQ  
//读取保存的下载信息（文件指针位置） =o)B1(v@.  
private void read_nPos() ?$Dc>  
{ ri2`M\;gt  
try{ rw$ =!iyO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); to{7B7t>q  
int nCount = input.readInt(); m;JB=MZ=m  
nStartPos = new long[nCount]; 7<*,O&![|  
nEndPos = new long[nCount]; b&*)C#7/T  
for(int i=0;i<nStartPos.length;i++) RhWW61!"  
{ Q-?6o  
nStartPos = input.readLong(); `qV*R 2  
nEndPos = input.readLong(); !{?<(6;t  
} 8Sk$o.Gy  
input.close(); KTE X]  
} $!vK#8-&{  
catch(IOException e){e.printStackTrace ();} O'{g{  
catch(Exception e){e.printStackTrace ();} (@Kc(>(: Y  
} :CsrcT=  
Eq=j+ch7  
pE {yVs  
private void processErrorCode(int nErrorCode) #0:rBKm,  
{ I_Omv{&u  
System.err.println("Error Code : " + nErrorCode); U/A [al  
} 1'%n?\OK66  
#]h&GX  
IAJ+n0U  
//停止文件下载 C{>dE:*K^  
public void siteStop() 1pz-jo,2'  
{ o;u~Yg  
bStop = true; E5IS<.  
for(int i=0;i<nStartPos.length;i++) PDS?>Jg(  
fileSplitterFetch.splitterStop(); XG E.*aI  
6!C>J#T  
Dqc2;>  
} B%WkM\\!^  
} RgVnx]IF  
//负责部分文件的抓取 NcX`*18  
**FileSplitterFetch.java tC5>K9Ed  
*/ IN,=v+A  
package NetFox; *#1
J  
2AW*PDncxP  
"H]R\xp  
import java.io.*; (v&iXD5t  
import java.net.*; rYM@e  
lV9  
:m<#\!?  
public class FileSplitterFetch extends Thread { _K B%g_{  
kz G W/  
uQ%3?bx)T  
String sURL; //File URL V@nZ_.  
long nStartPos; //File Snippet Start Position ^mouWw)a_  
long nEndPos; //File Snippet End Position ?K
Wo1  
int nThreadID; //Thread's ID p*U!9
4Pb  
boolean bDownOver = false; //Downing is over "8Lv  
boolean bStop = false; //Stop identical WtC&Qyuq  
FileAccessI fileAccessI = null; //File Access interface <`
u_O!h  
O"#/>hmv-  
0]zMb^wo  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +$F,!rV-s  
{ F##xVmR~  
this.sURL = sURL; CaVVlL  
this.nStartPos = nStart; X6BOB?  
this.nEndPos = nEnd; EeGTBVms  
nThreadID = id; !;K zR&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 i0Rj;E=:]  
} S%e)br}  
P26"z))~d  
p(fMM :  
public void run() f`iDF+h<6  
{ lqmr`\@)  
while(nStartPos < nEndPos && !bStop) 'hFL`F*  
{ DG}s`'  
cgO<%_l3`  
n:f&4uKoG<  
try{ JIsi  
URL url = new URL(sURL); |7Qe{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M@Ti$=  
httpConnection.setRequestProperty("User-Agent","NetFox");  >hzSd@J&  
String sProperty = "bytes="+nStartPos+"-"; <+<Nsza  
httpConnection.setRequestProperty("RANGE",sProperty); K &%8w  
Utility.log(sProperty); XM#nb$gl  
8A}<-?>  
"xnULQK  
InputStream input = httpConnection.getInputStream(); 7-0
j8$`  
//logResponseHead(httpConnection); =\mJ5v"hA  
P#V}l'j(<a  
BO8?{~i  
byte[] b = new byte[1024]; 5tk7H2K^<  
int nRead; 6Kw?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) skU }BUK6  
{ 2H`>Kj  
nStartPos += fileAccessI.write(b,0,nRead); s< Fp17
 
//if(nThreadID == 1) /x4L,UJ= P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X4+H8],)  
} \#I
Kirf?  
!R@jbM  
7#SfuZ0@  
Utility.log("Thread " + nThreadID + " is over!"); 5"(FilM  
bDownOver = true; 5m;BL+>YE  
//nPos = fileAccessI.write (b,0,nRead); Z>l<.T"t'  
} \}X[0ct2!  
catch(Exception e){e.printStackTrace ();} NNwGRoDco  
} |>1#)cONW  
} Wc,`L$Jx  
ru~!;xT  
<;
uM/vSi  
//打印回应的头信息 z:   
public void logResponseHead(HttpURLConnection con) OJhMM-  
{ ;]bW  
for(int i=1;;i++) r8!pk~R5]  
{ gf>GK/^HH  
String header=con.getHeaderFieldKey(i); fJ6Q:7  
if(header!=null) <@lj\,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); owI:Qs_/4  
Utility.log(header+" : "+con.getHeaderField(header)); k8l7.e*  
else w9mAeGyE  
break; J1Az+m  
} b|;h$
otC  
} (_6JQn  
JT~Dr KI_  
iXWB  
public void splitterStop() )vpYVr-  
{ #sk~L21A  
bStop = true; 8TK*VOf`  
} e,Y<$kPV  
?RW1%+[  
K-K>'T9F}  
} t;-F]  
bTZ.y.sI  
zL3zvOhu}  
/* wp5H|ctl  
**FileAccess.java b'z\|jY  
*//文件访问(定位，写) qQ6@43TC  
package NetFox; 8R-;c
BT
 
import java.io.*; nR wf;K  
x9S9%JG :  
-WR<tkK  
public class FileAccessI implements Serializable{  ls7P$qq  
FC||6vJth  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @8+v6z  
RandomAccessFile oSavedFile; K5t.
OAA:  
long nPos; pU[yr'D.r  
H S
Gz-  
-_eG/o=M  
public FileAccessI() throws IOException 3-)}.8F  
{ JAI.NKB3  
this("",0); LafBf6wds  
} JNJ6HyCU  
%+<1X?;,Fq  
rk@qcQR  
public FileAccessI(String sName,long nPos) throws IOException xU6dRjYhH9  
{ 4\g[&  
oSavedFile = new RandomAccessFile(sName,"rw"); ^U96p0H"T  
this.nPos = nPos; oA7|s1  
oSavedFile.seek(nPos); vy2"B ch  
} 5zkj;?s  
mZmEE2h  
$bfmsCcHL  
public synchronized int write(byte[] b,int nStart,int nLen) _-^mxC|M  
{ +Ar4X-A{y  
int n = -1; Ap;^\5  
try{ 1oQbV`P  
oSavedFile.write(b,nStart,nLen); AZA5>Y
 
n = nLen; W:6#0b"_#  
} Dhfor+Epy  
catch(IOException e) q(L.i)w$  
{ &0"*.:J9  
e.printStackTrace (); m_BpY9c]5  
} :}/\hz ,  
W tHJG5  
a1u4v/Qu9  
return n; |W@Ko%om  
} ; C(5lD&\5  
0uPcEpIA  
%L7DC`  
} 'zT7$ .L  
J^%E$s  
4xg1[Z%:  
/* s*Z yr%R  
**SiteInfoBean.java 4^4T#f2=e  
*/ BI<9xl]a  
package NetFox; #F2DEo^0  
j
VN=_Y}\  
Yl?s^]SFU  
public class SiteInfoBean { 0Js5 ' 9}H  
KxeqQ@  
;:ZD<'+N  
private String sSiteURL; //Site's URL 2Ur&_c6P  
private String sFilePath; //Saved File's Path MPyDG"B*  
private String sFileName; //Saved File's Name /6yVbo"  
private int nSplitter; //Count of Splited Downloading File R~hIoaiN  
7^UY%t  
R\#5;W^  
public SiteInfoBean() >r,z^]-  
{//nSplitter的缺省值为5 ,@f|t&  
//default value of nSplitter is 5 AeN:wOm  
this("","","",5); MBKF8b'k  
} KM"?l<x0Y  
Pc5C*{C  
9L4;#cy  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p|a`Q5z!  
{ k]RQ 7e  
sSiteURL= sURL; [eTEK W]  
sFilePath = sPath; l=S!cj;  
sFileName = sName; H!6&'=c{k  
this.nSplitter = nSpiltter; wc"~8Ah  
CtD<%v3`  
w T_l>u  
} .W2w/RayC  
:J2^Y4l2  
Nt?=0X|M  
public String getSSiteURL() ;b=7m#5  
{ _,UYbD\[J}  
return sSiteURL; E piF$n  
} 2\+N<-(F5  
Xa$%`  
2_?VR~mA#  
public void setSSiteURL(String value) 6Rq +=X  
{ K]7[|qf&   
sSiteURL = value; HL>l.IG?  
} FJ?]|S.?,  
p}wysVB  
QqB
Q[<_  
public String getSFilePath() s+G(N$0U  
{ r8czDc),b  
return sFilePath; J\'f5)k  
} 
?G]yU  
a_b+RMy  
3!#FG0Z  
public void setSFilePath(String value) 78?{;iNv  
{ u3&#UN  
sFilePath = value; }20tdD ~  
} QAY:H@Gt:  
+x4*T  
j-FMWEp  
public String getSFileName() I!K-* AB  
{ Cgf4E{\U!  
return sFileName; "15frr?  
} P(C5@x(Z  
;9J6)zg !n  
5,|{|/  
public void setSFileName(String value) 
3k8.5W  
{ 8/ukzY1!  
sFileName = value; X;vUz  
} rploQF~OFF  
3qV\XC+  
YuzVh9jTI  
public int getNSplitter() />>KCmc  
{ |&bucG=  
return nSplitter; ^ ~Tn[w W_  
} EgzdRB\Cf  
=~)rT8+)  
"#f5jH  
public void setNSplitter(int nCount) QNXS.!\P  
{ G2|G}#E  
nSplitter = nCount; k@[[vj|W  
} 2:yXeSeA  
} {!.w}  
2G3Hi;q18  
<f
MQ#No  
/* ps/|^8aGZ  
**Utility.java "`Xbi/i  
*/ F2)KAIl  
package NetFox; cnG>
EG  
2%H_%Zu9  
nmuU*oL  
public class Utility { X@)'E9g5:  
?1eu9;q\*  
(4rHy*6  
public Utility() jz\>VYi(7  
{ s]D1s%Mx  
lfR}cx  
6G_{N.{(  
} ZHj7^y@P  
Ngm/5Lc  
//线程睡眠 yK_$d0ZGE~  
public static void sleep(int nSecond) ._.Qf<7  
{ D@@"w+  
try{ 'Q.
5`o  
Thread.sleep(nSecond); mQ
K3YoC)  
} _u~`RlA  
catch(Exception e) m?
;/H  
{  (8/&  
e.printStackTrace (); zYftgH_o  
} ~ntDzF  
} /6y;fx  
+.m:-^9  
//日志 x Y}.mP  
public static void log(String sMsg) /<o?T{z<-  
{ "|PX5  
System.err.println(sMsg); 8>X]wA6q  
} Enp;-wG:-  
G^/8^Zi  
"!D,9AkZS  
public static void log(int sMsg) &.Yu%=}  
{ bGlr>@;-r  
System.err.println(sMsg); N4WX}  
} Ve40H6Ox  
} jgfr_"@A  
;9vY5CxzC  
1h{7dLA  
/* Y{X%C\  
**TestMethod.java RgzzbW  
*/ UGoB7TEfn  
package NetFox; ?rdWhF]  
J d,9<m$  
iN5[x{^t  
public class TestMethod { Xl>ZnI];  
veS) j?4  
k<rJm P{  
public TestMethod() $ao7pvU6  
{ ///xx/weblogic60b2_win.exe M{YN^ Kk  
try{ L#!m|_Mz  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^Qxv5HS2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); LO38}w<k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'GLpSWL+*  
fileFetch.start(); NA#,q 8  
} `9
|Uu#x  
catch(Exception e){e.printStackTrace ();} 6 8Vxy  

I(Vg
 
1buO&q!vn  
} zbvV:9N  
( F4c0  
$A T kCO  
public static void main(String[] args) H,LJ$ py  
{ s&\krW&  
new TestMethod(); }gd'pgN"t  
} akWOE}5#  
} va0}?fy.O%  
点击下载更多相关资料