http断点续传简单实现（java)

/* /|m2WxK)  
**SiteFileFetch.java ,$L4dF3  
*/ IxN9&xa
  
package NetFox; ='r!g  
import java.io.*; *\a4wZ6<3  
import java.net.*; ah$b[\#C  
un"Gozmt5  
& bm 1Fz  
public class SiteFileFetch extends Thread { bTN
gjc  
(62"8iD
6  
w>&aEv/f  
SiteInfoBean siteInfoBean = null; //文件信息Bean !<8W {LT  
long[] nStartPos; //开始位置 ' ,wFTV&  
long[] nEndPos; //结束位置 \[i1JG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  `,*3[  
long nFileLength; //文件长度 [ZwjOi:)  
boolean bFirst = true; //是否第一次取文件 8}x:`vDK  
boolean bStop = false; //停止标志 tmYz R%i  
File tmpFile; //文件下载的临时信息 y3Qsv  
DataOutputStream output; //输出到文件的输出流 !x=~g"d<&  
.WJYQi  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kPG-hD  
public SiteFileFetch(SiteInfoBean bean) throws IOException `:fZ)$sY  
{  :A_@,Q  
siteInfoBean = bean; ,Ks8*;#r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \~mT] '5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); LKB$,pR~1l  
if(tmpFile.exists ()) Y=?3 js?O  
{ cGzPI+F  
bFirst = false; OX0%C.K)hZ  
read_nPos(); i v38p%Zm  
} :uS\3toj  
else ]L.O8  
{ q'F+OQb1  
nStartPos = new long[bean.getNSplitter()]; <?.&^|kS  
nEndPos = new long[bean.getNSplitter()]; rl;
~pO5R9  
} yjX9oxhtL  
K&]G3W%V  
A2Ed0|By  
z (wc0I  
} 3BJ0S.TF  
Xza(k  
7hcYD!DS  
public void run() ;?iW%:_,  
{ '3fu  
//获得文件长度 %JBz5G  
//分割文件 V!A~K   
//实例FileSplitterFetch ]y'>=a|T  
//启动FileSplitterFetch线程 I-*S&SiXjI  
//等待子线程返回 83\pZ1>)_  
try{ G`61~F
%  
if(bFirst) B
%b4v  
{ u'DRN,h+  
nFileLength = getFileSize(); xGg )Y#  
if(nFileLength == -1) F^BS/Yag  
{ Qbn"=n2  
System.err.println("File Length is not known!"); J/aC}}5D  
} CYP q#rd  
else if(nFileLength == -2) .@U@xRu7|  
{ ^"2J]&x`G  
System.err.println("File is not access!"); O
m\vMd@!  
} 5L%'@`mX  
else Lck
K\`mh  
{ Hg izW  
for(int i=0;i<nStartPos.length;i++) zu{P#~21  
{ ,!y$qVg'\f  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PiIpnoM  
} b=NxUd O  
for(int i=0;i<nEndPos.length-1;i++) K7:)nv E  
{ -;m0R  
nEndPos = nStartPos[i+1]; q,|j]+
9q  
} l<LI7Z]A  
nEndPos[nEndPos.length-1] = nFileLength; 6SkaH<-&K  
} d.d/<  
} vJ[^K  
6ojo :-%Vf  

?M9=yA  
//启动子线程 ChPmX+.i_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vMH  
for(int i=0;i<nStartPos.length;i++) :q%M_  
{ #rfiD%c  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UECK:61Me  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f+,qNvBY/  
nStartPos,nEndPos,i); [!#L6&:a8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K`zdc`/  
fileSplitterFetch.start(); m@v\(rT.  
} IK=a*}19L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |&)dh<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); YkKi|k
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", SsDmoEeB[  
nEndPos = " + nFileLength); c9 _rmz8  
// fileSplitterFetch[nPos.length-1].start(); k2tF}  
P* BmHz4KL  
)lqAD+9Q  
//等待子线程结束 #a,PZDaE  
//int count = 0; bJ {'<J  
//是否结束while循环 9-a0:bP  
boolean breakWhile = false; Z
t{[*~  
L48_96  
~-Qw.EdC  
while(!bStop) s8t;.^1}  
{ CXM
Lt  
write_nPos();  {Gk1vcq  
Utility.sleep(500); ZG8DIV\D7  
breakWhile = true; 7#Kn8s   
/{n-Y/jp  
KBc1{adDx@  
for(int i=0;i<nStartPos.length;i++)
)g%d:xI  
{ `e&Suyf4B  
if(!fileSplitterFetch.bDownOver) FGmb<z 2p  
{ <=/hil  
breakWhile = false; L^?qOylu  
break; +lcbi  
} 4p;`C  
} :J&oX <nF^  
if(breakWhile) Ka V8[|Gn,  
break; #f]SK[nR  
s-Tv8goNV  
={&j07,*a  
//count++; H40p86@M  
//if(count>4) XK@E;Rv  
// siteStop(); HBXOjr<,{  
} 3;{kJQ
 
mNTzUoZF'@  
;'@9[N9  
System.err.println("文件下载结束！"); ~HsJUro  
}
m&,(Jla  
catch(Exception e){e.printStackTrace ();} `d`T*_  
} ^Y \"}D  
d^ 8ZeC#  

N<VJ(20y  
//获得文件长度 ?NsW|w_  
public long getFileSize() =X:Y,?  
{ E*K;H8}s  
int nFileLength = -1; )F]]m#`  
try{ z46~@y%k  
URL url = new URL(siteInfoBean.getSSiteURL()); >}i E(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &B1WtW
 
httpConnection.setRequestProperty("User-Agent","NetFox"); bK&+5t&  
g:8h|w)  
HQhM'x  
int responseCode=httpConnection.getResponseCode(); OA;XiR$xP  
if(responseCode>=400) Ai3*QX  
{ I,vJbvvl!  
processErrorCode(responseCode); ]GkfEh7/J  
return -2; //-2 represent access is error 4vB<fPN  
} $uVHSH5l  
ENs&RZ;  
t-bB>q#3>  
String sHeader; A$0fKko  
qu{&xjTH8  
;85>xHK
 
for(int i=1;;i++) Dp-z[]})1  
{ F{;((VboN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +VOK%8,p  
//Utility.log(in.readLine()); BUXpCxQ  
sHeader=httpConnection.getHeaderFieldKey(i); c 3)jccWTc  
if(sHeader!=null) R!gEwTk  
{ )1`0PJoHE  
if(sHeader.equals("Content-Length")) j'"J%e]  
{ .p" xVfi6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $DaNbLV  
break; r52gn(,  
} 6mxfLlZ  
} 00~mOK;1  
else 9EibIOD^/  
break; I:1C8*/  
} U8n V[  
} M
-Y_ Wb3  
catch(IOException e){e.printStackTrace ();} R8Fv{7]c  
catch(Exception e){e.printStackTrace ();} =MDysb&:  
],Do6 @M-  
B*Dz{a^.:  
Utility.log(nFileLength); oQ[f,7
u  
z5*'{t)  
u <v7;dF|s  
return nFileLength; ?J>  
} 7?w*]  
6q.Uhe_B  
dSV8q ,D  
//保存下载信息（文件指针位置） F0Yd@Lk$_  
private void write_nPos() *#+An<iT ;  
{ z[qDkL  
try{ |#R7wnE[k~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^9:Z7 >Z  
output.writeInt(nStartPos.length); 59;KQ  
for(int i=0;i<nStartPos.length;i++) pB0 \\wR  
{ ^WWQI+pk  
// output.writeLong(nPos); &7tbI5na@  
output.writeLong(fileSplitterFetch.nStartPos); vy:Z/1q  
output.writeLong(fileSplitterFetch.nEndPos); &E5g3lf  
} 'c$+sp ?  
output.close(); }9}h*RWm  
} 4zFW-yy  
catch(IOException e){e.printStackTrace ();} @?]RBX?a  
catch(Exception e){e.printStackTrace ();} A;?|&`f  
} &`2)V;t  
8$Y9ORs4  
$X
,D(  
//读取保存的下载信息（文件指针位置） (V2fRv  
private void read_nPos() f x+/C8GK  
{ iSs:oH3l  
try{ ~q25Yx9W@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1\I}2
;  
int nCount = input.readInt(); q9s=~d7  
nStartPos = new long[nCount]; Jij*x>K>y  
nEndPos = new long[nCount]; V1B5w_^>h'  
for(int i=0;i<nStartPos.length;i++) p9{mS7R9T  
{ tf`^v6m%]  
nStartPos = input.readLong(); ds[|   
nEndPos = input.readLong(); qF;|bF  
} 9V*qQS5<p  
input.close(); Se =`N  
} *VxgARIL  
catch(IOException e){e.printStackTrace ();} %6f*{G w  
catch(Exception e){e.printStackTrace ();} /aZ`[m2  
} I^$fM
dT  
-m~#Bq  
; kI134i=  
private void processErrorCode(int nErrorCode) WdbedU~`Q  
{ .3Oap*X  
System.err.println("Error Code : " + nErrorCode); a<bwzX|.  
} T1=fNF  
Z4 =GMXj  
S;`A{Mow  
//停止文件下载 Q>Yjy!.<^  
public void siteStop() VRB;$  
{ ^s"R$?;h  
bStop = true; dDLeSz$b  
for(int i=0;i<nStartPos.length;i++) Y`a3tO=Pd  
fileSplitterFetch.splitterStop(); {F.[&/A  
nZYBE030  
E$p+}sP(C  
} *b\t#meS&  
} I9ep`X6Y  
//负责部分文件的抓取 &gx%b*;`L0  
**FileSplitterFetch.java ER.}CM6{[  
*/ k@W1-D?  
package NetFox; U&p${IcEm  
nb%6X82Q  
@b2aNS<T  
import java.io.*; aAUvlb  
import java.net.*; =Jb>x#Y  
m!HJj>GEo  
RPRBmb940  
public class FileSplitterFetch extends Thread { Z/+#pWBI!  
6(ol
1 (U  
 Mb~
F%_  
String sURL; //File URL JZyAXm%  
long nStartPos; //File Snippet Start Position $*fMR,~t&  
long nEndPos; //File Snippet End Position |@4' <4t  
int nThreadID; //Thread's ID 7hPY_W y  
boolean bDownOver = false; //Downing is over 20Wg=p9L  
boolean bStop = false; //Stop identical sd|).;s}  
FileAccessI fileAccessI = null; //File Access interface r*Ca}Z  
+QJ#2~pE  
eehb1L2(b  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5$C-9  
{ T9  
this.sURL = sURL; U-M>=3|N  
this.nStartPos = nStart; +52{-a,>  
this.nEndPos = nEnd; -nV9:opD  
nThreadID = id; {_v#~595  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pFjK}JOF  
} *J`O"a  
/9fR'EO{x  
O:Tj"@h  
public void run() pYf-S?Y/V  
{ =D"#U#>;7&  
while(nStartPos < nEndPos && !bStop) {R`[kt  
{ Qt<&WB fn  
$(x]  
l+^*LqEW2  
try{ u]UOSfn  
URL url = new URL(sURL); g[4WzDF*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _X x/(.O  
httpConnection.setRequestProperty("User-Agent","NetFox"); kE1TP]|  
String sProperty = "bytes="+nStartPos+"-"; * r7rZFS  
httpConnection.setRequestProperty("RANGE",sProperty); --BW9]FW  
Utility.log(sProperty); b4N[)%@  
7B66]3v  
#o#H?Vo9b  
InputStream input = httpConnection.getInputStream(); ' S/gmn  
//logResponseHead(httpConnection);
fe_5LC"  
X#
^[<5  
GnJt0{  
byte[] b = new byte[1024]; G]&qx`TBK  
int nRead; }Jj}%XxKs  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) nAlQ7'  
{ `'7
R,  
nStartPos += fileAccessI.write(b,0,nRead); 63IM]J  
//if(nThreadID == 1) a9Zq
{Ysj  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [(7S.5I  
} ]Zh%DQ  
'!B&:X)  
5\VWCI  
Utility.log("Thread " + nThreadID + " is over!"); 7
s^'d,P  
bDownOver = true; X 0+vXz{~g  
//nPos = fileAccessI.write (b,0,nRead); {]4LULq  
} sK?twg;D*|  
catch(Exception e){e.printStackTrace ();} HJ.-Dg5U  
} KHvYUTY  
} 5]:U9ts#  
j^RmrOg,  
NC6&x=!3  
//打印回应的头信息 (KZ{^X?a  
public void logResponseHead(HttpURLConnection con) a/xn'"eli  
{ 19%imf  
for(int i=1;;i++) 5wU]!bxr  
{ M/`lM$98:  
String header=con.getHeaderFieldKey(i); Z6MO^_m2  
if(header!=null) !0<,@v"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 44j*KsBf  
Utility.log(header+" : "+con.getHeaderField(header)); SiN0OB  
else h^P#{W!e\  
break; 1<aP92/N&  
} g2Z`zQA7  
} }3WxZv]I}  
aV0"~5  
]\HvKCN}  
public void splitterStop() +^F Zq$NP  
{ "qy,*{~  
bStop = true; +k R4E23:  
} [AJJSd/:  
nQ3A~ ()  
&q*Aj17  
} l,aay-E  
V0a3<6@4  
w7&A0M  
/* '8kP.l  
**FileAccess.java ~6md !o%i  
*//文件访问(定位，写) )NT*bLRPQ  
package NetFox; (A.C]hD  
import java.io.*; {R{=+2K!|k  
EU Fa5C:  
y$M%2mh`  
public class FileAccessI implements Serializable{ @oGcuE  
+:/%3}
`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :7;@ZEe  
RandomAccessFile oSavedFile; H3oFORh  
long nPos; "_?nN"A7  
pEz_qy[#  
_+3::j~;m  
public FileAccessI() throws IOException 0JujesUw(  
{ Zx>=t
x}  
this("",0); "Z+k=~(  
} S$-7SEkO+  
ba9?(+i$h  
?:9"X$XR  
public FileAccessI(String sName,long nPos) throws IOException 8
zq=N#x  
{ [{/jI\?v  
oSavedFile = new RandomAccessFile(sName,"rw"); #,'kX
j  
this.nPos = nPos; lH~[f  
oSavedFile.seek(nPos); *lJxH8\  
} J]r^W)O  
m.0*NW  
u:  
public synchronized int write(byte[] b,int nStart,int nLen) |k00Z+O(  
{ z\4.Gm-  
int n = -1; `uTmw^pZX  
try{ 1G`Pmh@  
oSavedFile.write(b,nStart,nLen); <wHP2|<l*  
n = nLen; }Ou}+^Bc  
} +LJ73 !  
catch(IOException e) u)Whr@m  
{ 8H`[*|{'  
e.printStackTrace (); ;<4a*;IO  
} MiX43Pk]  
4Wp=y  
uhq8  
return n; ,<X9Y2B  
} |6y  
-trkA'ewZ  
F((4U"   
} 0<*<$U  
Vi|#@tC'  
{Y1Ck5  
/* cm+P]8o%{  
**SiteInfoBean.java &#i"=\d  
*/ b7ZSPXV  
package NetFox; r: :b  
`@yp+8  
PQE=D0  
public class SiteInfoBean { DVeE1Q  
2B`JGFcdcB  
\GU<43J2uo  
private String sSiteURL; //Site's URL b\5F]r  
private String sFilePath; //Saved File's Path !bP@n  
private String sFileName; //Saved File's Name {K!)Ss  
private int nSplitter; //Count of Splited Downloading File TkF[x%o  
bW:!5"_{H  
o}{5iTg=  
public SiteInfoBean() !dT4  
{//nSplitter的缺省值为5 5~S5F3  
//default value of nSplitter is 5 -tU'yKhn  
this("","","",5); ?&uu[y  
} Rk8P ax/JK  
NX&_p!_V  
NCD04U5y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) dgP3@`YS  
{ "uf%iJ:%  
sSiteURL= sURL; YchH~m
|  
sFilePath = sPath; #rg6,.I)<  
sFileName = sName; {
\\Tgs  
this.nSplitter = nSpiltter; '0,^6'VWOV  
f,Ghb~y  
!TcJ)0   
} &,)&%Sg[  
A/?7w   
c4zR*  
public String getSSiteURL() 7PF%76TO  
{ 51.%;aY~z  
return sSiteURL; fd9k?,zM  
} $NO&YLS@  
[KQ6Ta.  
q0\6F^;M  
public void setSSiteURL(String value) Zgb!E]V[
 
{ 'we>q@  
sSiteURL = value; >C~6\L`c  
} bQ5\ ]5M  
Ht&YC<X  
-%4,@ x`  
public String getSFilePath() @[v~y"tE}  
{ D3K8F@d  
return sFilePath; V^~:F  
} Xlt|nX~#;  
>KKMcTOYY  
tZB<on<.)  
public void setSFilePath(String value) 9MqGIOQ${j  
{ HtYwEjI  
sFilePath = value; e8b:)"R  
} 6d~'$<5on  
n._
-! WI  
N4HqLh23H  
public String getSFileName() ?Ss!e$jf  
{ ]J]h#ZH
x  
return sFileName; PmM3]xVzd  
} 2b8L\$1q  
QSf|nNT  
+qdEq_m  
public void setSFileName(String value) |sZHUf_  
{ f|oh.z_R  
sFileName = value; f`66h M[  
} 9(<@O%YU  
Yu`~U,m  
r:TH]hs12+  
public int getNSplitter() wwcBsJ1{  
{ ^LzF@{ G  
return nSplitter; _h1mF<\ X^  
} 7Fsay+a  
@9|hMo  
PeEj&4k  
public void setNSplitter(int nCount) U,1-A=Og{o  
{ f6"Z'{j  
nSplitter = nCount; ZSm3XXk  
} % %UE+u@J  
} Y\'}a+:@Ph  
+x}<IS8  
Fv`,3aNB  
/* 6;5Ss?ep  
**Utility.java iDrZc  
*/ Q=yg8CQ  
package NetFox; [)X\|pO&  
Z;)%%V%o  
B4 }bVjs  
public class Utility { hehFEyx  
^T-V^^#(  
S:ztXhif>  
public Utility() sdmT  
{ +m,yA mEEd  
2^yU ~`#  
iO; 7t@]-  
} ,~W|]/b<q  
x'R`. !g3  
//线程睡眠 Od)C&N=y  
public static void sleep(int nSecond) 9(wK@  
{ Wo=jskBrQ  
try{ `Ryp% Bn  
Thread.sleep(nSecond); <1M-Ro?5k  
} Aq7osU1B  
catch(Exception e) @7n"yp*"  
{ 0_t!T'jr7  
e.printStackTrace (); b>JDH1)  
} qJUK_6|3  
} y:l\$pGC%  
,$&&-p I]  
//日志 )w%!{hn  
public static void log(String sMsg) R*r#E{!V;  
{ S|+o-[e8O  
System.err.println(sMsg); 8}| (0mC  
} r]36zX v  
jrh43 \$*  
k|d+#u[Mj@  
public static void log(int sMsg) jRV/A!4  
{ VyGJ=[ ]  
System.err.println(sMsg); N ZSSg2TX#  
} UFuX@Lu0  
} $iz|\m  
4+ Z]3oIRE  
5/Uy{Xt  
/* 0{R=9wcc  
**TestMethod.java Hj,A5#|=J  
*/ P7~>mm+  
package NetFox; :9 ^* ^T  
kMd.h[X~  
Q]>.b%s[  
public class TestMethod { 1
&Zj  
~&bq0(  
12LL48bi  
public TestMethod() Z#\P&\`1z  
{ ///xx/weblogic60b2_win.exe E< fVZ,  
try{ \)|hogI|f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Tnm.A?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M=r)I~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5XBH$&Td  
fileFetch.start(); TRq6NB  
} yz8jw:d^-  
catch(Exception e){e.printStackTrace ();} v_-dx  
c0u^zH<  
8X|-rM{  
} H_Q+&9^/  
0"bcdG<}  
ea')$gR  
public static void main(String[] args) 'b{]:Y  
{ `W*U4?M  
new TestMethod(); D}X\Ca"h  
} 8-77d^cprR  
} 'Qe;vZ31K  
点击下载更多相关资料