http断点续传简单实现（java)

/* %P,^}h7  
**SiteFileFetch.java U2lC !j%K  
*/ @M^QhHs  
package NetFox; bvS\P!m\c  
import java.io.*; C,vc aC?  
import java.net.*; ,<r3Z$G  
"sX?wTag  
SJ7=<y}[d  
public class SiteFileFetch extends Thread { <?Izfl6  
~<[5uZIo  
KqUSTR1e[  
SiteInfoBean siteInfoBean = null; //文件信息Bean @/NZ>.  
long[] nStartPos; //开始位置 i=H>D  
long[] nEndPos; //结束位置 H6S vU  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :42;c:85  
long nFileLength; //文件长度 Mqf}Aiqk;  
boolean bFirst = true; //是否第一次取文件 SH$cn,3F8  
boolean bStop = false; //停止标志 `oRs-
,d|<  
File tmpFile; //文件下载的临时信息 8yz((?LrDh  
DataOutputStream output; //输出到文件的输出流 &
|"I0|tJ  
wK`ieHmp  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R6Z}/m  
public SiteFileFetch(SiteInfoBean bean) throws IOException Is6 _  
{ ~2DV{dyj  
siteInfoBean = bean; a;T[%'in  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MGKeD+=5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2$W,R/CLh  
if(tmpFile.exists ()) 8Pr7aT:,  
{ n9fA!Wic  
bFirst = false; fy>And*  
read_nPos(); iA{jKk=  
} r5da/*G/O  
else ~G:2iSi(#  
{ v[DbhIXU  
nStartPos = new long[bean.getNSplitter()]; 8|qB1fB  
nEndPos = new long[bean.getNSplitter()]; C5PBfn<j  
} 6 %k+
0\d  
:`^3MMLO  
Cm<j*Cnl  
S}Y|s]6
 
} ^zPEAXm  
(yAvDyJOn  
#Q7x:,f  
public void run() "~2#!bK7  
{ )Z]y.W)  
//获得文件长度 6?.pKFBZ  
//分割文件 DcR}pQ(e  
//实例FileSplitterFetch 5h=TV  
//启动FileSplitterFetch线程 <6O_t,K]  
//等待子线程返回 >aC\_Mc  
try{ kxqc6  
if(bFirst) tvH\iS#V  
{ D<3V#Opw  
nFileLength = getFileSize(); xm,`4WdG  
if(nFileLength == -1) V;hwAQbF  
{ eG
Sp(o56  
System.err.println("File Length is not known!"); Z*9]:dG:!  
} :Ip:sRz  
else if(nFileLength == -2) jM1%6  
{ 69j~?w)^  
System.err.println("File is not access!"); &<|-> *v  
} XZdr`$zf  
else u6Qf*_-K  
{ oSA*~N:  
for(int i=0;i<nStartPos.length;i++) b801OF  
{ V>jhGf  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PSf5p\<5  
}
71/m.w  
for(int i=0;i<nEndPos.length-1;i++) LQ(5D_yG.  
{
'
uf\.F  
nEndPos = nStartPos[i+1]; |*c\6 :  
} o|;eMO-  
nEndPos[nEndPos.length-1] = nFileLength; =Wk/q_.  
} ^g-t#O lD?  
} KA-/k@1&  
J1]w*2  
=e!l=d|/  
//启动子线程 )dIfr  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _:Jp*z  
for(int i=0;i<nStartPos.length;i++) 71.\`'  
{ {pb9UUP2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H&=n:'k^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), sLAuR  
nStartPos,nEndPos,i); k8 ;uC~L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;64mf`  
fileSplitterFetch.start(); 4]aiT8))  
} Z 5)_B,E:X  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,c%K)KuPK.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Vl 19Md  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 95^i/6Gl!P  
nEndPos = " + nFileLength); Gkv~e?Kc~^  
// fileSplitterFetch[nPos.length-1].start(); VwOG?5W/  
puS&S *  
m UWkb  
//等待子线程结束 hP1 l v7P  
//int count = 0; B?#kW!wj  
//是否结束while循环 M,t*nG  
boolean breakWhile = false; C3\E.u?  
"7yNKO;W  
[l':G]  
while(!bStop) y5/'!L)g  
{ ^6aS]t  
write_nPos(); *K,hrpYR  
Utility.sleep(500); $' (QTEM  
breakWhile = true; ! FR%QGn1  
4g7ja  
MZ5Y\-nq\  
for(int i=0;i<nStartPos.length;i++) 6 tc:A5mK  
{ -!|WZ   
if(!fileSplitterFetch.bDownOver) :GQIlA8cF$  
{ .5Knbc  
breakWhile = false; zRV!(Y
 
break; nJleef9  
} ]
dHB}  
} ^.D}
k  
if(breakWhile) Lvi[*une|  
break; ^IVe[P'  
;n} >C' :  
(rr}Pv%yb  
//count++; Ts(t:^  
//if(count>4) j1puB  
// siteStop(); 3duG.iUlL  
} zUs~V`0  
l@N;sI<O-  
OQ(D5GR:4  
System.err.println("文件下载结束！"); \9]I#Ih}M  
} X%GD0h]X#  
catch(Exception e){e.printStackTrace ();} \T`["<  
} .73zik   
hhpv\1h#  
G[3k  
//获得文件长度 F<Hqo>G  
public long getFileSize() 4L5o\'X  
{ ieo|%N{'  
int nFileLength = -1; Z&FkLww  
try{ x" 'KW (  
URL url = new URL(siteInfoBean.getSSiteURL()); X*sr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wfxOx$]zK  
httpConnection.setRequestProperty("User-Agent","NetFox"); X"[dQ_o  
k7^R,.c@  

'ySljo*It  
int responseCode=httpConnection.getResponseCode(); ~n[b^b  
if(responseCode>=400) ?wd|G4.Vo  
{ I?a8h`WS+  
processErrorCode(responseCode); >[ug zJ  
return -2; //-2 represent access is error v@8S5KJ  
} L 42|>%uo  
_+twqi  
ch@x]@-;A3  
String sHeader; G HD^%)T5^  
|l|_
dn  
9W*.lf  
for(int i=1;;i++) fokwW}>B[f  
{ fyI_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D@8jGcz62  
//Utility.log(in.readLine()); b'velj3A  
sHeader=httpConnection.getHeaderFieldKey(i); RT%x&j  
if(sHeader!=null) V: ^JC>6  
{ \\jIl3Z  
if(sHeader.equals("Content-Length")) ;rd6ko  
{ ~~PgF"v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M@|w[ydQG  
break; U~aWG\h#X  
} 3p=vz'  
} rdO@X9z  
else '_B_&is  
break; ]o-Fi$h!  
} Kb}MF9?:e  
} K~c^*;F  
catch(IOException e){e.printStackTrace ();} 6Wj@r!u  
catch(Exception e){e.printStackTrace ();} U1l0Uke  
fr+@HUOxsl  
xXF2"+  
Utility.log(nFileLength); (NX)oP  
ajW[eyX  
nV'
3sUvR#  
return nFileLength; [#p&D~Du&  
} Bi]D{m
9  
?>sQF4 V"  
Bwjg#1E  
//保存下载信息（文件指针位置） $^t<9"t  
private void write_nPos() ,
Ij=b  
{ #wF
1  
try{ O -G1})$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )S^z+3p  
output.writeInt(nStartPos.length); J"-_{)0lD  
for(int i=0;i<nStartPos.length;i++) R1}IeeZO?&  
{ sltk@  
// output.writeLong(nPos); Nz~(+pVWg5  
output.writeLong(fileSplitterFetch.nStartPos); OR]T`meO  
output.writeLong(fileSplitterFetch.nEndPos); )o{VmXe@@  
} yVaUt_Zi  
output.close(); hp*<x4%*a"  
} t\8&*(&3F  
catch(IOException e){e.printStackTrace ();} C1d 04
Q  
catch(Exception e){e.printStackTrace ();} 'Q5&5UrBr  
} c4\C[$  
,'~#Ch  
8Jr1_a  
//读取保存的下载信息（文件指针位置） ?0{yq>fTu  
private void read_nPos() i^WIr h3a  
{ U IfH*6X  
try{ V]rhVMA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?w*yW;V`  
int nCount = input.readInt(); ~ FGe~  
nStartPos = new long[nCount]; 1]j^d  
nEndPos = new long[nCount]; > @+#  
for(int i=0;i<nStartPos.length;i++) a5a1'IVq  
{ !i^]UN   
nStartPos = input.readLong(); }qAVN  
nEndPos = input.readLong(); L1wZU,o  
} P.cO6+jGR  
input.close(); H'EY)s Hi  
} ZRnL_z~  
catch(IOException e){e.printStackTrace ();} w
:}C8WKw  
catch(Exception e){e.printStackTrace ();} 3qtr9NI  
} vf<UBa;Xm  
M ?*Tf&  
34ha26\np  
private void processErrorCode(int nErrorCode) vIVr@1S  
{ ^_68]l=  
System.err.println("Error Code : " + nErrorCode); O+_N!/  
} ZHCr2^w6  
Q[uAIyv0  
Ea4_Qmn  
//停止文件下载 If;R?j0;Q  
public void siteStop() 4O(@'#LLz  
{ r,4lqar;E  
bStop = true; OEnDsIhq  
for(int i=0;i<nStartPos.length;i++) W5.
Va.  
fileSplitterFetch.splitterStop(); dAL3.%  
! RPb|1Y}+  
9${Xer'  
} n_P3\Y|  
} qaG#;  
//负责部分文件的抓取  %H& ].47  
**FileSplitterFetch.java V@%  
*/ %&+TbDE+T  
package NetFox; E"#Xc@  
.%'Z~|K4  
4PWAGuN^  
import java.io.*; @A{m5
h  
import java.net.*; j)Y[4 ^k^  
gRAC d&)  
` H XEZ|  
public class FileSplitterFetch extends Thread { e3v5,.  
vc8?I."?  
ong""K4H  
String sURL; //File URL 3?.1nGu  
long nStartPos; //File Snippet Start Position s]H^wrg&  
long nEndPos; //File Snippet End Position xx }GOY.J  
int nThreadID; //Thread's ID G 4qy*.  
boolean bDownOver = false; //Downing is over fxgU~'  
boolean bStop = false; //Stop identical \G>ZkgU  
FileAccessI fileAccessI = null; //File Access interface iY~rne"l  
O4L#jBa+  
m!O;>D  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Yp1bH+/u  
{ gcf6\f}\<  
this.sURL = sURL; Dx-KMiQ,"(  
this.nStartPos = nStart; q+ pOrGh  
this.nEndPos = nEnd; U>
P|X=)  
nThreadID = id; zN{J
J3-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 RJ~%0  
} >o~Z>lr  
O'$K],=BS  
L9FHgl?  
public void run() MT6/2d  
{ (UYF%MA}"  
while(nStartPos < nEndPos && !bStop) Qx)Jtb0`V  
{ ]
]BOk  
<G~>~L.E  
PB53myDQ  
try{ g=l:cVr8y  
URL url = new URL(sURL); p $ouh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lA^+Flh  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1J}8sG2`  
String sProperty = "bytes="+nStartPos+"-"; y(a!YicA?  
httpConnection.setRequestProperty("RANGE",sProperty); eV7u*d?  
Utility.log(sProperty); ;%!B[+ut"  
wO.iKX;  
Q@-ovuxi  
InputStream input = httpConnection.getInputStream(); XK ApLz  
//logResponseHead(httpConnection); >cN~U
3  
VDGCWg6z  
"i&"* ~  
byte[] b = new byte[1024]; u~1o(Zn =  
int nRead; P0Z!?`e=M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Zy0aJN>  
{ +4qU>  
nStartPos += fileAccessI.write(b,0,nRead); ZA(T  
//if(nThreadID == 1) :I1_X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \or G63T:  
} .*YD&(  
?okx<'"[  
jS<_ )  
Utility.log("Thread " + nThreadID + " is over!"); tPfFqqT  
bDownOver = true; ]zfG~^.  
//nPos = fileAccessI.write (b,0,nRead); 7~1IO|4t  
} Vj?DA5W`'  
catch(Exception e){e.printStackTrace ();} +&|S'7&{  
} xV\5<7qk5g  
} $uDqqG(^  
TDt
Amk  
nFRsc'VT  
//打印回应的头信息 :5fAPK2r<  
public void logResponseHead(HttpURLConnection con) l2jF#<S@  
{ ihCIh6  
for(int i=1;;i++) 58V[mlW)O0  
{ nBItO~l  
String header=con.getHeaderFieldKey(i); XORk!m|  
if(header!=null) 51BlM%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); H1EDMhn/  
Utility.log(header+" : "+con.getHeaderField(header)); "v-(g9(  
else !j:`7PT\  
break; ^W?Z  
} h8e757z  
} w5=tlb  
PVOx`<ng  
3)=c]@N0  
public void splitterStop() u3 0s_\  
{ 28.~iw  
bStop = true; 3AcD,,M>>  
} eqAW+Ptx  
q'Wr[A40j  
>rsqH+oL  
} !g!5_|  
qJ4T]FVN  
`D$JvN  
/* 9W ^xlid6  
**FileAccess.java ~|ss*`CT  
*//文件访问(定位，写) "=/ f$Xf  
package NetFox; _aWl]I){5  
import java.io.*; ;)AfB#:d  
>slm$~rv  
hr05L<?H  
public class FileAccessI implements Serializable{ *f%>YxF  
Q
]/Uq~m C  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 cD|Htt"  
RandomAccessFile oSavedFile; M<PIeKIEB  
long nPos; "KX=ow#z|  
IuF
_M<d,  
Nes=;%&]G  
public FileAccessI() throws IOException W,^W^:m-x  
{ j
=?'4sF  
this("",0); SMH
<'F7i  
} `Z"Q^  
?p<.Fv8.  
uw(NG.4  
public FileAccessI(String sName,long nPos) throws IOException &fa5laJb  
{ `o]g~AKX  
oSavedFile = new RandomAccessFile(sName,"rw"); #|GSQJ$F)`  
this.nPos = nPos; e=vsuqGT  
oSavedFile.seek(nPos); eB>s=}|  
} ew _-Eb  
?<Wb@6k
h`  
r}#\BbCv;7  
public synchronized int write(byte[] b,int nStart,int nLen) z!;1i[|x  
{ BVsD( @lX  
int n = -1; fA/m1bYxg  
try{ (Rt7%{*  
oSavedFile.write(b,nStart,nLen); o2z]dTJ}o  
n = nLen; [u}(57DS  
} 7\]E~/g  
catch(IOException e) 7/7Z`  
{ sg
'pO*_&  
e.printStackTrace (); <@wj7\pQ  
} L(T12s  

<JMcIV837  
bV8g|l-4(  
return n; 40E
#JF#  
} k>x&Ip8p  
&k-Vcrcz  
wNFz*|n  
} H{J'# 9H  
g~V+4+  
qd3Q}Lk  
/* No]~jnqDM  
**SiteInfoBean.java o<IAeH {+  
*/ (C4fG@n  
package NetFox; Lip4)Y [  
,p(<+6QZ  
76hOB@  
public class SiteInfoBean { 3rLTF\  
`w I/0  
!Z VU,b>  
private String sSiteURL; //Site's URL _iNq"8>2  
private String sFilePath; //Saved File's Path ~{sG| ;/!*  
private String sFileName; //Saved File's Name !EUan  
private int nSplitter; //Count of Splited Downloading File lj+u@Z<xA  
W>-Et7&2  
w 4[{2  
public SiteInfoBean() oh#\]c\f  
{//nSplitter的缺省值为5 4DZ-bt'  
//default value of nSplitter is 5 *
5w{8  
this("","","",5); 4_Dp+
^JF  
} ()&
~@1U  
^B8b%'\  
CLvX!O(~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {uzf"%VtP  
{ pTIf@n6I  
sSiteURL= sURL; )95f*wte  
sFilePath = sPath; `+6R0Ch  
sFileName = sName; W9NX=gE4  
this.nSplitter = nSpiltter; *
CHI2MB  
rE@T79"  
=zQN[  
} ;WR,eI..  
Ft}@1w5  
{s.=)0V  
public String getSSiteURL() w]N!S;<N  
{ %|s+jeUDn|  
return sSiteURL; (vT+IZEI  
} %iV^S!e  

boDt`2=  
%^RN#_ro(3  
public void setSSiteURL(String value) ]_N|L|]M  
{ 95el'K[R  
sSiteURL = value; )"Ztlhs`#  
} d!eYqM7-G  
9on@Q_7m  
~69&6C1Ch  
public String getSFilePath() )1X#*mCxk  
{ P.gb1$7<  
return sFilePath; '7O3/GDK  
} Gea\,{E9xA  
13taFVdU  
$Xq!L  
public void setSFilePath(String value) 6gc>X%d`K  
{ ,v"YqD+GC5  
sFilePath = value; x.-+[l[1 !  
} / m=HG^!  
-'6Dg  
yPq'( PV  
public String getSFileName() AK@9?_D  
{ c/sC&i;%O  
return sFileName; | Bi!  
} G^ :C+/)  
l\i)$=d&g  
;^Dpl'v%\  
public void setSFileName(String value) gEjdN.  
{ =>-Rnc@  
sFileName = value; Mo^ od<  
} -B +4+&{T  
0Vx.nUQ
  
nr<4M0tIp  
public int getNSplitter() ]
q4rlT.i  
{ =E.wv  
return nSplitter; @;"|@!l|  
} E>K!Vrh-L  
z<Nfm  
7 qS""f7  
public void setNSplitter(int nCount) -fDnA4;  
{
AIZ]jq  
nSplitter = nCount; .[_L=_.  
} Rb'|EiNPw  
} c Vc-  
|:gf lseE  
W)bLSL]`E  
/* Z.Lc>
7o  
**Utility.java E 7{U|\  
*/ ,y#Kv|R  
package NetFox; +L;e^#>d  
`x*Pof!Io  
A*\.NTM  
public class Utility { $&n=$C&x  
iUN Ib
 
XuFYYx~ ^3  
public Utility() ,0!}7;j_c  
{ 'd9INz.  
#AJM6* G9  
[MUpxOAsd  
} EFM5,gB.m  
, K~}\CR  
//线程睡眠 [DI+~F  
public static void sleep(int nSecond) "~|6tQLc  
{ FOE4>zE  
try{ &O
H={Au  
Thread.sleep(nSecond); W:pIPDx1=!  
} cQ R]le%(  
catch(Exception e) N2;B-UF 7  
{ a.k.n<  
e.printStackTrace (); 0Qf,@^zL*  
} },{$*f[  
} [M=7M}f;  
QTk}h_<u  
//日志 !$gR{XH$]  
public static void log(String sMsg) GjvOM y  
{ N5lDS  
System.err.println(sMsg); I&x=;   
} 9y"@(  
i9,geQ7d  
p8Qk'F=h  
public static void log(int sMsg) fHx*e'eA  
{ vdc\R?  
System.err.println(sMsg); ek*rp`y]  
} 
%]}  
} |ATvS2  
+%h8r5o1  
c(xrP/yOwi  
/* 286jI7T  
**TestMethod.java ,l\-xSM  
*/ L>Fa^jq5  
package NetFox; 86=}ZGWd  
_-K2/6zy  
#lL^?|M  
public class TestMethod { UGV+/zxIM  
Yi%;|]  
KPKt^C  
public TestMethod()
kTOzSiq  
{ ///xx/weblogic60b2_win.exe l
Z]ZDb?P  
try{ y51e%n$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :!WHFB o 8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); u}macKJmp\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z>k#n'm^z  
fileFetch.start(); yEqps3%  
} *av<E  
catch(Exception e){e.printStackTrace ();} E Nhl&J  
"jKY1*?  
-b9\=U[  
} @=}0`bE  
SJn;{X>)q  
[}E='m}u9+  
public static void main(String[] args)  M^=zt  
{ On9A U:\  
new TestMethod();
@k,#L`3^  
} FXG]LoP  
} "c
%0P"u  
点击下载更多相关资料