http断点续传简单实现（java)

/* PX?^v8wlqL  
**SiteFileFetch.java q'X#F8v  
*/ F^=y+}]=  
package NetFox; Y$qjQ1jF+  
import java.io.*; YC*`n3D|'  
import java.net.*; !Uhcjfq`e  
X-j<fX_  
y35e3  
public class SiteFileFetch extends Thread { CdtwR0  
^6!8)7b  
)>;387'Y  
SiteInfoBean siteInfoBean = null; //文件信息Bean NpGz y`&b  
long[] nStartPos; //开始位置 bF
+d_t  
long[] nEndPos; //结束位置 PK_2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Y)M-?|4  
long nFileLength; //文件长度 T%YN(f  
boolean bFirst = true; //是否第一次取文件 4!?4Tc!X  
boolean bStop = false; //停止标志 a4q02 cV  
File tmpFile; //文件下载的临时信息 eYv+tjIF  
DataOutputStream output; //输出到文件的输出流 =v{
R(IX%  
ksYPF&l  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） A=*6|1w;  
public SiteFileFetch(SiteInfoBean bean) throws IOException $! g~pV  
{ |CBJ8],mT  
siteInfoBean = bean; KF`m
OSP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8yuTT^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Imo?)dYK  
if(tmpFile.exists ()) :a( Oc'T  
{ mt-t8~A  
bFirst = false; =]<X6!0mR  
read_nPos(); u:^9ZQ+  
} ^)3=WD'!  
else ,^@/I:  
{ ~UsE"5  
nStartPos = new long[bean.getNSplitter()]; ,JJ1sf2A  
nEndPos = new long[bean.getNSplitter()]; )_Iu7b  
} ;y>}LGG  
$^#q0Yx  
,awkL :  
L1q]  
} Q:Y`^jP   
"m}N hoD4  
op_ 1J;RF  
public void run() j<L!(6B  
{ O%Qz6R  
//获得文件长度 sWP_fb1  
//分割文件 |j$$0N  
//实例FileSplitterFetch 8: VRq  
//启动FileSplitterFetch线程 h>/L4j*Z  
//等待子线程返回 N,ZmGzNP)  
try{ RRGs:h@;  
if(bFirst) krXU*64  
{ !nF.whq  
nFileLength = getFileSize(); pq
]>Ep  
if(nFileLength == -1) (T.g""N~`  
{ ^3Z~RK\}  
System.err.println("File Length is not known!"); pEb/yIT"  
} T<mP.T,$!  
else if(nFileLength == -2) z_Pq5  
{ qqu]r  
System.err.println("File is not access!"); LO)QEU
G  
} zR}vR9Ls  
else o~VZ%B  
{ `Z (`  
for(int i=0;i<nStartPos.length;i++) p.vxrk`c  
{ Q+E)_5_sA  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F[0w*i&u5  
} z+nq<%"'  
for(int i=0;i<nEndPos.length-1;i++) SCq3Kh  
{ 08nA}+k  
nEndPos = nStartPos[i+1]; b.xG'  
} "s\himoa  
nEndPos[nEndPos.length-1] = nFileLength; Lo +H&-  
} H*&!$s.  
} }wGy#!CSza  
VS5D)5w#  
U H6 Jvt  
//启动子线程 NF_[q(k'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2K{)8;^  
for(int i=0;i<nStartPos.length;i++) !LpFK0rw  
{ ,.uI>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .gw6W0\F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8oP"?ew#  
nStartPos,nEndPos,i); x\5\KGw16  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %lGg}9k'  
fileSplitterFetch.start(); TnPx.mwK\  
} 5^36nEoA(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F\+!\b*lP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a &hj|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", stOD5yi  
nEndPos = " + nFileLength); :j;_Xw  
// fileSplitterFetch[nPos.length-1].start(); 28 ;x5m)N  
{ b7%Zd3-  
D(Q=EdlO  
//等待子线程结束 )AAPT7!U  
//int count = 0; 6W N(Tw  
//是否结束while循环 0C0ld!>r  
boolean breakWhile = false; ~*RBMHs  
l'"Ici#7Ls  
ztV%W6  
while(!bStop) ^FK-e;J  
{ ZJ|&t  
write_nPos(); \Jr7
Hy1;  
Utility.sleep(500); OJ)XJL  
breakWhile = true; o 0H.DeP  
C.hRL4+;Zm  
JE[J}-2  
for(int i=0;i<nStartPos.length;i++) X@@7Qk  
{ (.9H1aO46|  
if(!fileSplitterFetch.bDownOver) jp#/]>(9Z  
{ fZ  pUnc  
breakWhile = false; B..> *Xb  
break; zR }vw{  
} [vcSt5R=  
} uSNlI78D  
if(breakWhile) 8Y~\:3&1<  
break; ~G8haN4  
*En4~;l  
-KiI&Q  
//count++; gPy}.g{tH$  
//if(count>4) !F#^Peb  
// siteStop(); e `IL7$  
} &=v5M9GR]  
8>ODtKI*  
e1 P(-V  
System.err.println("文件下载结束！"); =tqChw   
} V%n7h&\%  
catch(Exception e){e.printStackTrace ();} \Oa11c`6  
} .\|}5J9W  
{tF)%>\#  
e&F=w`F\  
//获得文件长度 vA0f4W 8+  
public long getFileSize() Rc`zt7hbJ  
{ EdS7m,d  
int nFileLength = -1; Hr;\}  
try{ ~{npG  
URL url = new URL(siteInfoBean.getSSiteURL()); $R/@%U)-o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WD?COUEox  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4Pr@<S"U  
-y)g}D%  
OG2&=~hOz-  
int responseCode=httpConnection.getResponseCode(); wXUgxa  
if(responseCode>=400) F!ra$5u  
{ @i@f@.t  
processErrorCode(responseCode); r_M5:Rz  
return -2; //-2 represent access is error hE}y/A[  
} 9I*`~il>{  
NpF)|Ppb{  
P<IZ%eS3B  
String sHeader; 5t[7taLX\  
^ &VN=Y6z  
 uE3xzF  
for(int i=1;;i++) bODyJ7=[  
{ <|4L+?_(&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #^bn~  
//Utility.log(in.readLine()); 2p8}6y:}7  
sHeader=httpConnection.getHeaderFieldKey(i); ,M$J yda  
if(sHeader!=null) 5*r5?ne  
{ h>&t
``<  
if(sHeader.equals("Content-Length")) %jj\w>  
{ H.[t&VO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @ R;o $n  
break; 3+WostOx  
} !i?aRI/6  
} ,L^ag&!4  
else Y .\<P*iO  
break; d0N/!;  
} H4g1@[{|0O  
} 1_G5uHO  
catch(IOException e){e.printStackTrace ();} km9@*@)  
catch(Exception e){e.printStackTrace ();} <5sP%Fs)  
EJJW  
[fr!J?/@  
Utility.log(nFileLength); ny[\yj4F  
uKd79[1  
ak]H|D" 9  
return nFileLength; >Gxh=**F  
} %vjfAdC  
A7sva@}W  
UpCkB}OhR1  
//保存下载信息（文件指针位置） *Au[{sR  
private void write_nPos() #=aTSw X  
{ K&/!3vc  
try{ !yf7y/qY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]ag^~8bG @  
output.writeInt(nStartPos.length); F]`_akE  
for(int i=0;i<nStartPos.length;i++) Gque@u  
{ </)QCl'd  
// output.writeLong(nPos); wVtBH_>  
output.writeLong(fileSplitterFetch.nStartPos); lyQNE3   
output.writeLong(fileSplitterFetch.nEndPos); 3d*wZ9qz  
} :N ]H"u9X  
output.close(); 7?"-NrW~  
} 2U`g[1  
catch(IOException e){e.printStackTrace ();} `NARJ9M   
catch(Exception e){e.printStackTrace ();} =1Tn~)^O  
} wb/@g=`d  
BZAF;j  
m15> ^i^W  
//读取保存的下载信息（文件指针位置） 2N}h<Yd9  
private void read_nPos() +pJ~<ug]  
{ q OX=M  
try{ vy1N,8a  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); R#Hz%/:|A  
int nCount = input.readInt(); TWTh!  
nStartPos = new long[nCount]; P_%kYcX'  
nEndPos = new long[nCount]; yu@u0vlc  
for(int i=0;i<nStartPos.length;i++) 5{O9<~,  
{ %Y<3v\`_  
nStartPos = input.readLong(); "BD$-]  
nEndPos = input.readLong(); lehuJgz'OO  
} $BWA=2$  
input.close(); fd*<m8  
} ;0]s:0WD0P  
catch(IOException e){e.printStackTrace ();} I vD M2q8f  
catch(Exception e){e.printStackTrace ();} ]ppws3*Pa  
} ()%;s2>F  
&(,-:"{pNR  
*4RL  
private void processErrorCode(int nErrorCode) xzOM\Nq?O  
{ `Fs-z  
System.err.println("Error Code : " + nErrorCode); ^DOQ+  
} B5H=#  
DzE_p- zs  
wBIhpiJX0  
//停止文件下载 SbN.z  
public void siteStop() -
<M'h  
{ ck K9@RQ  
bStop = true; W`` 
-/  
for(int i=0;i<nStartPos.length;i++) /D ~UK"}  
fileSplitterFetch.splitterStop(); } {<L<  
`*HM5 1U  
(`FY{]Wz!  
} 
- {|  
} UA}N  
//负责部分文件的抓取 |t&gyj  
**FileSplitterFetch.java _/)HAw?k  
*/  _V_GdQ  
package NetFox; Jw)-6WJ!uO  
}@Ou]o  
<CY<-H  
import java.io.*; V}+Ui]ie|I  
import java.net.*; #JW~&;  
(GXFPEH8  
mM
)d`br  
public class FileSplitterFetch extends Thread { K1[(%<Gp  
!S5_+.U#  
R\,qL-Br  
String sURL; //File URL 6T ,'Oz  
long nStartPos; //File Snippet Start Position d2[R{eNX=  
long nEndPos; //File Snippet End Position 
V{yk  
int nThreadID; //Thread's ID Tl`HFZQ1  
boolean bDownOver = false; //Downing is over f4r)g2Zb[  
boolean bStop = false; //Stop identical 6`U]%qx_I  
FileAccessI fileAccessI = null; //File Access interface -Gmg&yQ9  
{'1e?  
muKCCWy#  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `/L D:R  
{ TwL
Q;Q  
this.sURL = sURL; 7bC)Co#:  
this.nStartPos = nStart; U# 7K^(E9  
this.nEndPos = nEnd; XD$;K$_7  
nThreadID = id; ?N(opggiD  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;J&9l >  
} <A@qN95m  
Ul%D}(,  
'(!
U5j  
public void run() ;iTZzmB  
{ 19 <Lgr  
while(nStartPos < nEndPos && !bStop) +N:=|u.g  
{ LGPPyKNx  
LQ3J$N  
^muPjM+D  
try{ ^P}c0}^  
URL url = new URL(sURL); NG?-dkD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  D/]  
httpConnection.setRequestProperty("User-Agent","NetFox"); W@FRKDixG  
String sProperty = "bytes="+nStartPos+"-"; ~Op~~ m  
httpConnection.setRequestProperty("RANGE",sProperty); |]'0z0>  
Utility.log(sProperty); C}8 3t~Q  
Yi+$g  
&n-)Alx  
InputStream input = httpConnection.getInputStream(); e<1)KqG  
//logResponseHead(httpConnection); uhO-0H  
35PIfqm  
#AUV&pI[  
byte[] b = new byte[1024]; CwQRHi  
int nRead; S^*ME*DDz  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3KN>t)A#  
{ g]Fm%iy  
nStartPos += fileAccessI.write(b,0,nRead); ERZWK  
//if(nThreadID == 1) d<+@cf_9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /j:fc?yv  
} wC~LZSTt  
$KMxq=  
6h3TU,$r  
Utility.log("Thread " + nThreadID + " is over!"); 2(iv+<t  
bDownOver = true; u RPvo}!=1  
//nPos = fileAccessI.write (b,0,nRead); %% A==_b  
} a<d$P*I(cH  
catch(Exception e){e.printStackTrace ();} u[~= a5:4  
} jpRC
6b?  
} do&0m[x%  
_5&LV2  
P[<EFjE  
//打印回应的头信息 >nOzz0,  
public void logResponseHead(HttpURLConnection con) +!Lz]@9K  
{ iDrQ4>  
for(int i=1;;i++) unN=yeut  
{ Fvae
lB  
String header=con.getHeaderFieldKey(i); x!QA* M  
if(header!=null) Xl\yOMfp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6 ~d\+aV  
Utility.log(header+" : "+con.getHeaderField(header)); H!vX#  
else 0V5{:mzA  
break; S1D;Xv@  
} 'e5,%"5(c  
} Fb&WwGY,P  
m?_@.O@]  
A ^U`c'$  
public void splitterStop() 1G62Qu$O  
{ F`U YgN  
bStop = true; #xTu {  
} q;#:nf"  
Z&Ao;=Gp1  
A!.*
eIV|  
} xA {1XS}  
)!jX$bK  
<Z^qBM  
/* ztHEXM.  
**FileAccess.java ~zD*=h2C  
*//文件访问(定位，写) 7R5!(g  
package NetFox; (043G[H'.  
import java.io.*; F,>-+~L=  
tDwj~{a~  
aT`. e  
public class FileAccessI implements Serializable{ 2#g4R  
to"[r  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 a-Ef$(i_  
RandomAccessFile oSavedFile; z}f;_NX  
long nPos; CY i{WV(:  
bf&k:.v'8  
c`x[C  
public FileAccessI() throws IOException /!HFi>  
{ 4,P!D3SH  
this("",0); qk=0ovUzg  
} ;|H(_J=6k  
Hg%8Q@  
y_A?}'X  
public FileAccessI(String sName,long nPos) throws IOException Jk3V]u  
{ !-Br?  
oSavedFile = new RandomAccessFile(sName,"rw"); j~VHU89  
this.nPos = nPos; `.F+T)
G  
oSavedFile.seek(nPos); PML+$  
} j+7ok 5J#  
?)V}_%fVv  
yNkE>  
public synchronized int write(byte[] b,int nStart,int nLen) kFsq23Ne  
{ U**v'%{s  
int n = -1; B@@j-  
try{ Th(F^W9  
oSavedFile.write(b,nStart,nLen); Eh*t;J=O  
n = nLen; Yvbk[Rb  
} <;.
->73E  
catch(IOException e) PZsq9;P$  
{ I7/X6^/}  
e.printStackTrace (); /'g"Ys?3  
} y.m;4((  
EU@XLm6  
.7Lv  
return n; vspub^;5\  
} iJD_qhd7  
Q($
aN-  
?B`Yq\L)  
} *2tG07kI  
Gaxa~?ek  
ZUxlk+o9d  
/* !ii'hwFm$  
**SiteInfoBean.java oHI/tS4 _  
*/ </B5^}  
package NetFox; Jb4A!g5C  
UZq1qn@+  
*)H&n>"e  
public class SiteInfoBean { Vn1hr;i]  
Wr+1G 8  
d[Lr`=L;  
private String sSiteURL; //Site's URL ,)
JSXo  
private String sFilePath; //Saved File's Path 2r~&+0sBP  
private String sFileName; //Saved File's Name =-GHs$u%f  
private int nSplitter; //Count of Splited Downloading File *zR   
`*hrU{b  
baVSQtda  
public SiteInfoBean() J)xc mK  
{//nSplitter的缺省值为5 U&<Nhh  
//default value of nSplitter is 5 61^5QHur
 
this("","","",5); ZD'fEqM  
} 6}EC)j;Fw  
>
HH49cCo  
1S26
Y|L)  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) SWGD(]}uz  
{ %: .{?FB_  
sSiteURL= sURL; Oor&1  
sFilePath = sPath; umo@JWr  
sFileName = sName; fsDwfwil*  
this.nSplitter = nSpiltter; >
IzUn: 0F  
ugI9rxT]Kv  
Xu8_
<%  
} h&4f9HhS=  
-n`igC  
fQB>0RR2  
public String getSSiteURL() g@jAIy]  
{ L9=D,C~  
return sSiteURL; /\_wDi+#  
} xE4iey@\}  
*4tJ|m6"Y6  
CNiUHUD  
public void setSSiteURL(String value) xXktMlI  
{ D/&^Y'|T  
sSiteURL = value; iS"(  
} 01nbR+e  
"7k 82dw  
-OS&(7  
public String getSFilePath() u0(PWCi2
 
{ d* 6 lJT  
return sFilePath; Pkbx/\  
} oe:@7stG  
@!:~gQ  
l`vb  
public void setSFilePath(String value) ByK!r~>Z1Q  
{ Hi 1@  
sFilePath = value; E\(dyq/  
} _IOt(Zb(  
<6s?M1J  
BWct0=  
public String getSFileName() E.kjYIH8  
{ uWYI p\NN  
return sFileName; xjOj1Hv  
} MxY~(TVPK  
-U?Udmov  
Eo$7W5hJ  
public void setSFileName(String value) %Hk9.1hn5  
{ x}W,B,q  
sFileName = value; %\ i 7  
} ZgcJxWC<  

lKd+,<  
\P;%f

N  
public int getNSplitter() $`Z-,AJc  
{ hwaU;>F  
return nSplitter; $EB&]t+  
} Dg$Z5`%k8  
. _5g<aw;  
)@xHL]!5m  
public void setNSplitter(int nCount) &;%z1b>F  
{ o 26R]  
nSplitter = nCount; <#s=78 g.3  
} L*Mt/  
} +h}>UK\  
+ou ]|  
P9)E1]Dc$  
/* zoV4Gl  
**Utility.java P,x'1`k~  
*/ TX96 ^EoH  
package NetFox; G`B e~NU  
;/ iBP2
 
[4NJ]r M%  
public class Utility { fWx %?J  
CfguL@tR.  
:esHtkyML  
public Utility() SO#NWa<0|  
{ i+$G=Z#3E  
BitP?6KX  
B&~#.<23:  
} 4LRrrW  
vps</f!  
//线程睡眠 v2e*mNK5  
public static void sleep(int nSecond) =l_B58wrx  
{ )uvs%hK  
try{ @_Ko<fKSX  
Thread.sleep(nSecond); "lcNjyU\O  
} ZqhCGHy  
catch(Exception e) #,0PLU3%  
{ *OOi  
e.printStackTrace (); +/t
Nd2  
} @)A)cBv#  
} 42a.@JbLQ  
j@xerY  
//日志 ]Q Y:t:-  
public static void log(String sMsg) IJxBPwh  
{ nyyKA_#:5  
System.err.println(sMsg); ~C1lbn b  
} i`3h\ku  
`ZCeuOH  
UQ;ymTqdc  
public static void log(int sMsg) ,m| :U  
{ zo,`V
ibx<  
System.err.println(sMsg); WoVPp*zlX  
} ,f@$a3}'Lx  
} "HCJ!  
cFcn61x-  
nRYHp7`  
/* v71j1Q}6  
**TestMethod.java
"P)f,n  
*/ &vf9Gp+MK  
package NetFox; !_Z\K$Ns  
l<5
@a (  
`0.<  
public class TestMethod { Y}<w)b1e|  
,(H`E?m1w4  
J*Dt\[X  
public TestMethod() c418Tj
O;  
{ ///xx/weblogic60b2_win.exe _l`d+ \#  
try{ UF3g]>*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~=$0=)c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YP*EDb?f  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j_::#?o!/  
fileFetch.start(); _4eSDO[h  
} !c}?u_Z/  
catch(Exception e){e.printStackTrace ();} ldd|"[Ds  
]ZV.@%+  
v6Vieo=  
} J!O{.
v  
a$0,T_wD  
Gwyjie9t  
public static void main(String[] args) [D!-~]5  
{ KIyhvY~  
new TestMethod(); Gk<M@d^hQ  
} h^yLmRL  
} ;VhilWaF-  
点击下载更多相关资料