http断点续传简单实现（java)

/* ?1Vx)j>|  
**SiteFileFetch.java <|X+T,  
*/ ~UQ<8`@a  
package NetFox; #Yp&yi }  
import java.io.*; fO^s4gWTg  
import java.net.*; _dCDT$^&r  
C"0 VOb  
)D'#>!Y  
public class SiteFileFetch extends Thread { vfx{:3fO  
|wQ3+WN|  
sKR%YK "A  
SiteInfoBean siteInfoBean = null; //文件信息Bean Fs=x+8'M  
long[] nStartPos; //开始位置 vkR~nIp  
long[] nEndPos; //结束位置 {%^4%Eco  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !;[cJbqnh  
long nFileLength; //文件长度 |JWYsqJ0U  
boolean bFirst = true; //是否第一次取文件 n c~JAT#'  
boolean bStop = false; //停止标志 :Aqt
PV'  
File tmpFile; //文件下载的临时信息 DrAIQ7Jd  
DataOutputStream output; //输出到文件的输出流 aj .7t=^  
n&|N=zh  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） SAf)#HXa  
public SiteFileFetch(SiteInfoBean bean) throws IOException /n>vPJvz  
{ G973n  
siteInfoBean = bean; *14:^neoI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -O=xgvh"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Y$c7uA:4  
if(tmpFile.exists ()) @]}/vsI m  
{ _Ye.29  
bFirst = false; P0OMu/
 
read_nPos(); H]wP\m)  
} T3SFG]H  
else yENAcsv  
{ T;{:a-8  
nStartPos = new long[bean.getNSplitter()]; (.YSs   
nEndPos = new long[bean.getNSplitter()]; EL z5P}L6  
} Ars*H,9>e  
}0@@_Y]CC  
s?->2gxhx  
Y+vIU*O  
} +\&6Zbn  
~=[5X,Ta  
U#iW1jPE2  
public void run() ed_+bCNy  
{ 'o0o.&/=  
//获得文件长度 yIngenr$  
//分割文件 bT T>  
//实例FileSplitterFetch 6biR5&Y5U&  
//启动FileSplitterFetch线程 2$!,$J-<Y  
//等待子线程返回 es%py~m)  
try{ S<'_{uz  
if(bFirst) Q2woCxB  
{ Lpkx$QZ  
nFileLength = getFileSize(); $XMpC
{  
if(nFileLength == -1) l=Pw yJ  
{ ,2^A<IwR  
System.err.println("File Length is not known!"); JTBt=u{6^  
} /z`tI  
else if(nFileLength == -2) S0:Oep   
{ k&f/f  
System.err.println("File is not access!"); ]F>#0Rdc  
} eK*oV}U-k  
else K4]ZVMm/*  
{ 5|Z8UzL  
for(int i=0;i<nStartPos.length;i++) F!/-2u5gF  
{ *HGhm04F{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); v+79#qWK|n  
} c9CFGo?)N  
for(int i=0;i<nEndPos.length-1;i++) ' ;nG4+K  
{ o.Y6(o  
nEndPos = nStartPos[i+1]; CH|cK8q  
} 5M5vxJ)Lh  
nEndPos[nEndPos.length-1] = nFileLength; |/%5~=%7  
} fB,eeT1v?h  
} $ywROa]  
9b,0_IMHH  
J:ka@2>|  
//启动子线程 |r)QkxdU,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; V,'_BUl+x  
for(int i=0;i<nStartPos.length;i++) l`:u5\ rM  
{ 1ZYo-a;)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T:2f*!r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3k(tv U+eC  
nStartPos,nEndPos,i); ?K2}<H-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cTRtMk%^  
fileSplitterFetch.start(); QUvSeNSp  
} %N(>B_t\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #9.%>1{6Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t?Qbi)T=z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", uWFyI"  
nEndPos = " + nFileLength); ;PU'"MeB "  
// fileSplitterFetch[nPos.length-1].start(); _FcTY5."S  
+Ig%h[1a  
ZUS5z+o  
//等待子线程结束 xaoR\H  
//int count = 0; (&r` l&0  
//是否结束while循环 [UC_  
boolean breakWhile = false; Iu`S0#+  
g.%} +5  
s3Zt)xQ3  
while(!bStop) v#<
{Y'K  
{ xVX:kDX  
write_nPos(); 7I&o  
Utility.sleep(500); 7l=Tl[n  
breakWhile = true; IO=$+c  
$_TS]~y4
}  
UF }[%Sa  
for(int i=0;i<nStartPos.length;i++) =2QP7W3mg<  
{ f
R{_P  
if(!fileSplitterFetch.bDownOver) 7ZyP  
{ r7R.dD/.  
breakWhile = false; R4JfH  
break; &nI>`Q'  
} Qo^(r$BD  
} I_Gz~qk6  
if(breakWhile) mD&I6F[s  
break; %eIaH!x:  
wF%RM$  
rKFnivGT  
//count++; $M!i
Q"bb  
//if(count>4) w4}Q6_0v  
// siteStop(); K{`R
`SXD  
} lA1  
y06**f)  
Tbv w?3  
System.err.println("文件下载结束！"); i4h`jFS  
} 9%NobT  
catch(Exception e){e.printStackTrace ();} IvY3iRq6  
} AJ
&j|/  
*V\.6,^v  
EU|IzUjFj|  
//获得文件长度 (S+/e5c)  
public long getFileSize() ?nbu`K6T  
{ EQd<!)HZ  
int nFileLength = -1; 1ywdcg  
try{ 19y,O0# _  
URL url = new URL(siteInfoBean.getSSiteURL()); 3#dz6+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C#yRop_d]o  
httpConnection.setRequestProperty("User-Agent","NetFox"); FBB<1({A  
G}+@C]  
\f(zMP  
int responseCode=httpConnection.getResponseCode(); E"S#d&9  
if(responseCode>=400) |o9`h9i  
{ u7RlxA:  
processErrorCode(responseCode); sP2Uj  
return -2; //-2 represent access is error ZS(%!+M  
} W}3%BWn  
} eHxw+.  
o 7tUv"Rs  
String sHeader; <rK[&JlJ  
4'*.3f'bp  
_xm<zy{`S  
for(int i=1;;i++) }d>.Nj#zh  
{ QKq4kAaJ!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |%ZJN{!R  
//Utility.log(in.readLine()); :3D6OBkB  
sHeader=httpConnection.getHeaderFieldKey(i); &QW&K  
if(sHeader!=null) _6r[msH"  
{ 9s[   
if(sHeader.equals("Content-Length")) 0!ZaR6  
{ `O0Qtq.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c^pQitPv  
break; "Ueq  
} _,aFQ^]'9  
}
P!IA;i  
else ob2_=hQnC  
break; 6D2ot&5WW  
} +75"Q:I  
} .[1 f$  
catch(IOException e){e.printStackTrace ();} D&uaA-;s  
catch(Exception e){e.printStackTrace ();} &S66M2  
aQ\SV0PI  
+>*=~R
 
Utility.log(nFileLength); oQmXKV+[v  
r nr-wUW@  
mTWd+mx  
return nFileLength; )8#-IXxp  
} #5{xWMp/0  
KU oAxA  
>bQOpGy}l  
//保存下载信息（文件指针位置） X`WS&!C<  
private void write_nPos() \mJR^t  
{ ~1}fL 1~5  
try{ j$/#2%OVN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $t}W,?   
output.writeInt(nStartPos.length); (}>)X]  
for(int i=0;i<nStartPos.length;i++) <8kCmuGlk  
{ LAlX|b  
// output.writeLong(nPos); >O
v
z;  
output.writeLong(fileSplitterFetch.nStartPos); %$Py@g  
output.writeLong(fileSplitterFetch.nEndPos); H'/V<
%  
} /j$pV  
output.close(); @sZ7Ka  
} X@tA+  
catch(IOException e){e.printStackTrace ();} F {L#  
catch(Exception e){e.printStackTrace ();} 
ocK4Nxs  
} ]S@T|08b  
-=8f*K[W  
@%L  
//读取保存的下载信息（文件指针位置） lemV&$WN|  
private void read_nPos() XXA'B{@Y)  
{ 9
e>2kd  
try{ 3gVU#T[[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +2 oZML  
int nCount = input.readInt(); cl&?'` )  
nStartPos = new long[nCount]; ~uZ9%UB_m  
nEndPos = new long[nCount]; _xi&%F/  
for(int i=0;i<nStartPos.length;i++) j#P4&  
{ OAW_c.)5D  
nStartPos = input.readLong(); B]<N7NYn1  
nEndPos = input.readLong(); =FIZh}JD  
} HDzeotD  
input.close(); @jMo/kO/A  
} -X7x~x-  
catch(IOException e){e.printStackTrace ();} uaKbqX  
catch(Exception e){e.printStackTrace ();} V(0Y   
} `RE>gX  
bf2n%-&9g  
n7Eh!<  
private void processErrorCode(int nErrorCode) BxlhCu  
{ PHIc7*_  
System.err.println("Error Code : " + nErrorCode); *?uUP  
} ;'V[8`Z@  
MMET^SO  
i>CR{q  
//停止文件下载 Ti0kfjhX7  
public void siteStop() !.O[@A\.-  
{ K,|3?CjS  
bStop = true; GIpYx`mHi  
for(int i=0;i<nStartPos.length;i++) y&8`NS#_p?  
fileSplitterFetch.splitterStop(); -@#],s7  
xy!E_CuC$  
v<2,OcH  
} V?x&\<;,  
} A
&v Qtd  
//负责部分文件的抓取 9IG<9uj  
**FileSplitterFetch.java (0LA.aBIf  
*/ 'sa)_?Hy  
package NetFox; #Y-_kQV*  
*)^ZUk  
VbJE zl  
import java.io.*; {6qxg_{  
import java.net.*; :PY8)39@K  
9 4lt?|3=  
 (yd(ZY  
public class FileSplitterFetch extends Thread { @zi0:3`#0\  
pG)dF@  
l,b,U/3R.  
String sURL; //File URL ,H
/O"%OJ  
long nStartPos; //File Snippet Start Position rOEBL|P0  
long nEndPos; //File Snippet End Position z4(\yx  
int nThreadID; //Thread's ID Yqo@ g2g  
boolean bDownOver = false; //Downing is over r<srTHGLo  
boolean bStop = false; //Stop identical ^*$!9~  
FileAccessI fileAccessI = null; //File Access interface IV':sNV  
~.U\Y  
hH;i_("i(h  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zIS ,N '  
{ 06.8m;{N  
this.sURL = sURL; w^nA/=;r  
this.nStartPos = nStart; `VGw5o  
this.nEndPos = nEnd; Th\T$T`X$  
nThreadID = id; '4u/g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &X` lh P  
} d*k5h<jM
 
Rb:?%\=  
knV*,   
public void run() oVbs^sbRH  
{ A(`Mwh+  
while(nStartPos < nEndPos && !bStop) |+sAqx1IF  
{ p}gA8o  
T5T[$%]6  
T<Zi67QC@  
try{ 5i'?oXL  
URL url = new URL(sURL); L5KcI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KY%qzq,n  
httpConnection.setRequestProperty("User-Agent","NetFox"); a#CjGj)  
String sProperty = "bytes="+nStartPos+"-"; Ow5VBw(  
httpConnection.setRequestProperty("RANGE",sProperty); ?g@X+!RB  
Utility.log(sProperty); =<aFkBX-  
u=~`5vA  
E1Q#@*rX>  
InputStream input = httpConnection.getInputStream(); })uyq_nz  
//logResponseHead(httpConnection); t&5Ne ?  
?-`&YfF  
d>zC[]1  
byte[] b = new byte[1024]; ""N~##)8  
int nRead; 0/7.RpX,.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u`(yT<>H  
{ $*_79F2zN  
nStartPos += fileAccessI.write(b,0,nRead); ObreDv^,  
//if(nThreadID == 1) \{a5]G(4s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Wk/Q~o  
} &><b/,]  
upeioC q  
.s41Tc5u  
Utility.log("Thread " + nThreadID + " is over!"); 1LvR,V<  
bDownOver = true; Rd]<591  
//nPos = fileAccessI.write (b,0,nRead); K~3Y8ca  
} pg_H'0R  
catch(Exception e){e.printStackTrace ();} ^AOJ^@H^>  
} B^R44j]3"  
} ,v=pp;  
QpoC-4F  
x6Gl|e[jv  
//打印回应的头信息 i$6a0'@U  
public void logResponseHead(HttpURLConnection con) P&tw!B  
{ *a{WJbau]  
for(int i=1;;i++) /!p}H'jl  
{ f;,*P,K  
String header=con.getHeaderFieldKey(i); 0blbf@XA  
if(header!=null) [fvjvN`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r5(efTgAd+  
Utility.log(header+" : "+con.getHeaderField(header)); s+&0Z3+  
else sP%b?6  
break; TA:
#K  
} -3b_}b
y  
} j:2F97  
>/%XP_q%`e  
}rs>B,=*k  
public void splitterStop() RVs=s}|>*  
{ psz0q|
 
bStop = true; :+ 1Wmg  
} $ZB`4!JxG  
W*v3B.  
A>FWvlLw'm  
} N Mx:Jh-YN  
Y!Io @{f  
m$pRA0s2`  
/* [!uVo>Q4  
**FileAccess.java 3%Q9521  
*//文件访问(定位，写) ;3bUgI}.J  
package NetFox; 3QdCu<eBZ  
import java.io.*; QX=x^(M$m  
H5UF r,t  
#!#s7^%K&  
public class FileAccessI implements Serializable{ @+y,E-YTdV  
m] -cRf)9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3r,Kt&2$  
RandomAccessFile oSavedFile; V 7ZGT  
long nPos; JZ:yPvJ  
GWWaH+F[h  
H(M{hfa|  
public FileAccessI() throws IOException /?z3*x  
{ 9v8^uPA  
this("",0); #<u;.'R  
} Ra H1aS(  
:l iDoGDi  
)24M?R@r  
public FileAccessI(String sName,long nPos) throws IOException !gfd!R  
{ aS\$@41"  
oSavedFile = new RandomAccessFile(sName,"rw"); tB(~:"|8  
this.nPos = nPos; puMbB9)  
oSavedFile.seek(nPos); iY&I?o!Ch  
} E8p,l>6(f  
Mk+G(4p  
+#<Z/  
public synchronized int write(byte[] b,int nStart,int nLen) rQU6*f  
{ %9S0!h\  
int n = -1; 5)hfI7{d  
try{ =]"I0G-s!
 
oSavedFile.write(b,nStart,nLen); |z:4T%ES  
n = nLen; {c*5 )x!  
} CHD.b%_|  
catch(IOException e) A&WC})H5  
{ `
c-omNu  
e.printStackTrace (); 'ShK7j$  
} \[*q~95$v  
/Bh*MH  
kBoQjOV`  
return n; %*Uc,V  
} h@(+(fVHrp  
n}(A4^=4KQ  
K1]3zLnS  
} *-Vr=e<8   
%yk_(3a  
o[+t}hC[  
/* wArfnB&  
**SiteInfoBean.java 6f ?,v5  
*/ Vry_X2  
package NetFox; HSAr6h  
!7MRHI/0C  
WBm)Q#1:  
public class SiteInfoBean { v+SdjFAY  
r`h".=oD
 
~<s^HP2U{
 
private String sSiteURL; //Site's URL urCTP.F  
private String sFilePath; //Saved File's Path ~{vB2  
private String sFileName; //Saved File's Name kY{$[+-jR  
private int nSplitter; //Count of Splited Downloading File 0 ]L  
^M;#x$Y?  
#h4FLF_w  
public SiteInfoBean() ]6Awd A  
{//nSplitter的缺省值为5 ZKpJc'h  
//default value of nSplitter is 5 ('Uj|m}9  
this("","","",5); ;YW@ 3F-h  
} VYO1qj  
lCl5#L9  
w&Gc#-B  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }N$f=:i
I  
{ EUQtl_h/H  
sSiteURL= sURL; d)acWF\  
sFilePath = sPath; /!MKijI  
sFileName = sName; &;L=f;   
this.nSplitter = nSpiltter; ^w<aS w  
D3P/: 4  
t4/ye>P &  
} }<l:~-y|  
!@N?0@$/  
uN>5Eh&=Pf  
public String getSSiteURL() h8(>$A-  
{ PwthYy  
return sSiteURL; 0\B{~1(^  
} 0_MtmmL.  
d%-/U!z?  
%d(= >  
public void setSSiteURL(String value) 8"ZS|^#  
{ .5}Gt>4XM  
sSiteURL = value; 57gt"f  
} 4K? \5(b  
JPng !tvR  
8UqH"^9.Q7  
public String getSFilePath() xSSEDfq  
{ tpO'<b  
return sFilePath; 7C,giCYU  
} y)CvlI  
[A"=!e$<  
GdVF;  
public void setSFilePath(String value) jY]51B
 
{ Gsb^gd  
sFilePath = value; N)R5#JX  
} *L$_80  
" r o'?  
1 ptyiy  
public String getSFileName() [0]A-#J  
{ ZILJXX4  
return sFileName; "*F`,I3  
} ~QxW^DGa7]  
B%MdJD>  
pq&[cA_w  
public void setSFileName(String value) K%x]:|,>M  
{ IM/xBP  
sFileName = value; x-X~'p'f  
} BI%XF 9{  
#u8#< ,w  
9q_{_%G%  
public int getNSplitter() =W:=}ODD  
{ ?6
`B;_m  
return nSplitter; kROIVO1|`  
} mTxqcQc:7  
<r t$~}  
+qC[X~\  
public void setNSplitter(int nCount) ]S[?tn  
{ 0F/[GZ<k  
nSplitter = nCount; 3]mprX'  
} T]-MrnO  
} [xr^t1  
L/C~l3  
AD?XJ3  
/* M\{\WyeX  
**Utility.java e(|Z<6  
*/ -bHlFNRm  
package NetFox; /(51\RYkir  
'hs4k|B  
aK@ Y) Ju'  
public class Utility { 4Yik
C  
4\ Xaou2V[  
-$[&{.B.  
public Utility() 1Z @sh>X|  
{ s_VcC_A  
/]!2k9u\  
6WGg_x?3  
} }P.Z}n;Uj  
;<m`mb4x[  
//线程睡眠 7_76X)gIV  
public static void sleep(int nSecond) rlY0UA,  
{ >L2_k'uE+;  
try{ SM4`Hys;p  
Thread.sleep(nSecond); B\)Te9k'  
} TaBya0-  
catch(Exception e) DR}I+<*%aD  
{ _Tor9Tj  
e.printStackTrace (); nM2<u[{gF  
} Y'iyfnk  
} Xi[]8o  
n>j2$m1[  
//日志 :e;6oC*"q  
public static void log(String sMsg) DlE,aYB  
{ $">j~!'  
System.err.println(sMsg); nf 8V:y4  
} FrXP"U}Y  
Nn FR;  
7`;sX?R
 
public static void log(int sMsg) W wPzm?30  
{ K8X7IE  
System.err.println(sMsg); f/#Id]B  
} 'A7!@hVy  
}
8lYA6A  
1?FG3X 5  
DMG~56cTO,  
/* /ta}12Z  
**TestMethod.java A%W]XEa<  
*/ )PP yJ@M  
package NetFox; 8e*skL  
2RX]~}
  
b^h_`  
public class TestMethod { a- rR`  
@`4T6eL5  
^WO3,  
public TestMethod() cE 'LE1DK  
{ ///xx/weblogic60b2_win.exe <Q9l'u]3$c  
try{ _90D4kGU  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kWZY+jyt P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 018SFle  
SiteFileFetch fileFetch = new SiteFileFetch(bean); BA2"GJvfIA  
fileFetch.start(); O?Bf (y  
} m.m6.  
catch(Exception e){e.printStackTrace ();} :&vX0 Ce:  
?IHt T3'Rt  
uv/\1N;V3  
} jj2iF/  
Intuda7e1  
b},2A'X  
public static void main(String[] args) -!1=S: S  
{ uNyN[U  
new TestMethod(); 5cIZ_#  
} EyA ny\"  
} <}{<FXk[  
点击下载更多相关资料