前言
一直很想知道IDE是如何自动去生成类的构造和getter、setter方法，大概是有个想法，获取当前的类，利用反射去获取属性名和类型，然后生成，所以我想自己试试。
写个模板类
package common;
public class Templates {
public static final String T_CLASS = "package {0};\n\n{1}public class {2} {\n\n{3}\n\n{5}\n\n{4}\n}";
public static final String T_GET = "\tpublic {0} get{1} () {\n\t\treturn {2};\n\t}\n";
public static final String T_SET = "\tpublic void set{0}({1} {2}) {\n\t\tthis.{2}={2};\n\t}\n";
public static final String T_ATTR1 = "\tprivate {0} {1};\n";
public static final String T_ATTR2 = "\t\tthis.{0}={0};\n";
public static final String T_IMPORT = "import java.util.Date;\n\n";
public static final String T_CONSTRUCT = "\tpublic {0}({1}) {\n\t\tsuper();\n{2}\n\t}\n";
public static String format(String pattern, String ... arguments){
String format = pattern;
for(int i=0;i<arguments.length;i++){
format = format.replace("{"+i+"}",arguments[i]);
}
return format;
}
public static String loadTemplate(String clazz,String pack,String port,
String attrs,String get_set,String construct){
return format(T_CLASS, clazz,pack,port,attrs,get_set,construct);
}
}
创建一个实体类
package cc.vvxtoys.pojo;
public class Student {
private int id;
private String name;
private String sex;
private String school;
}
工具类
package common;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import org.apache.log4j.Logger;
public class Common {
private static Logger log = Logger.getLogger(Common.class);
//获得绝对路径
public static String absolutePath(String pack, String name, String suffix) {
List<String> list = new ArrayList<>();
String absolutePath = "";
try {
String packPath = pack.replace(".", "\\");
File src = new File(".\\src");
File file = new File(src.getCanonicalPath());
File[] fs = file.listFiles();
for (int i = 0; i < fs.length; i++) {
if (fs[i].isDirectory()) {
if (fs[i].getAbsolutePath().endsWith(packPath)) {
absolutePath = fs[i].getAbsolutePath() + "\\" + name + suffix;
return absolutePath;
}
list.add(fs[i].getAbsolutePath());
}
}
for (int j = 0; j < Integer.MAX_VALUE; j++) {
if (j>0&&j == list.size() - 1) {
break;
}
File tmp = new File(list.get(j));
fs = tmp.listFiles();
for (int k = 0; k < fs.length; k++) {
if (fs[k].isDirectory()) {
if (fs[k].getAbsolutePath().endsWith(packPath)) {
absolutePath = fs[k].getAbsolutePath() + "\\" + name + suffix;
return absolutePath;
}
list.add(fs[k].getAbsolutePath());
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return absolutePath;
}
public static String loadFile(String path) {
File file = new File(path);
String str = null;
BufferedReader reader = null;
StringBuffer buffer = new StringBuffer();
String charset = "utf-8";
try {
InputStreamReader is = new InputStreamReader(new FileInputStream(file), charset);
reader = new BufferedReader(is);
while ((str = reader.readLine()) != null) {
buffer.append(str);
buffer.append("\n");
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
return buffer.toString();
}
public static void writeFile(String filePath, String str, boolean flg) {
try {
FileWriter fw = new FileWriter(new File(filePath), flg);
PrintWriter pw = new PrintWriter(fw);
pw.println(str);
log.info("写入成功。。。");
pw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void writeFile(String filePath, String str) {
try {
FileWriter fw = new FileWriter(new File(filePath), true);
PrintWriter pw = new PrintWriter(fw);
pw.println(str);
log.info("写入成功。。。");
pw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
//首字母大写
public static String upInitials(String str){
StringBuffer buff = new StringBuffer();
buff.append(String.valueOf(str.charAt(0)).toUpperCase());
buff.append(str.toCharArray(),1,str.length()-1);
return buff.toString();
}
}
构建类
package auto_get_set;
import java.lang.reflect.Field;
import common.Common;
import common.Templates;
/**
* @author vvxtoys
*/
public class ClassGenerator {
private String [] attrs;
private String [] types;
private String absolutePath;
private String context;
private String clazz;
public ClassGenerator(Object obj) {
loadClass(obj);
}
public void loadClass(Object obj){
Field [] fs = null;
try{
String claname = obj.getClass().getSimpleName();
String suffix = ".java";
String pack = obj.getClass().getPackage().getName();
absolutePath = Common.absolutePath(pack, claname, suffix);
context = Common.loadFile(absolutePath);
clazz = claname;
Class clazz = Class.forName(obj.getClass().getName());
fs = clazz.getDeclaredFields();
attrs = new String[fs.length];
types = new String[fs.length];
for(int i=0;i<fs.length;i++){
attrs[i] = fs[i].getName();
types[i] = fs[i].getType().getSimpleName();
}
}catch(Exception e){
e.printStackTrace();
}
}
public void autoGetSet(){
String str = context.substring(0,context.lastIndexOf("}"));
String get_set = "";
for(int i=0;i<attrs.length;i++){
String g1 = Templates.format(Templates.T_GET, types[i],Common.upInitials(attrs[i]),attrs[i]);
String s1 = Templates.format(Templates.T_SET, Common.upInitials(attrs[i]),types[i],attrs[i]);
get_set+=g1+s1;
}
str+=get_set;
str+="}";
context = str;
}
public void autoConstruct(){
String str = context.substring(0,context.lastIndexOf("}"));
String c1 = Templates.format(Templates.T_CONSTRUCT, clazz,"","");
String params = "";
String field = "";
for(int i=0;i<attrs.length;i++){
params+=types[i]+" "+attrs[i]+",";
field+=Templates.format(Templates.T_ATTR2, attrs[i]);
}
params = params.substring(0,params.length()-1);
String c2 = Templates.format(Templates.T_CONSTRUCT, clazz,params,field);
str +=c1+c2;
str+="}";
context = str;
}
public void updateClass(){
Common.writeFile(absolutePath, context,false);
}
public void run(){
autoConstruct();
autoGetSet();
updateClass();
}
}
测试
package auto_get_set;
import cc.vvxtoys.pojo.Student;
public class Test {
public static void main(String[] args) {
ClassGenerator g = new ClassGenerator(new Student());
g.run();
}
}
构建之后的实体类
package cc.vvxtoys.pojo;
public class Student {
private int id;
private String name;
private String sex;
private String school;
public Student() {
super();
}
public Student(int id,String name,String sex,String school) {
super();
this.id=id;
this.name=name;
this.sex=sex;
this.school=school;
}
public int getId () {
return id;
}
public void setId(int id) {
this.id=id;
}
public String getName () {
return name;
}
public void setName(String name) {
this.name=name;
}
public String getSex () {
return sex;
}
public void setSex(String sex) {
this.sex=sex;
}
public String getSchool () {
return school;
}
public void setSchool(String school) {
this.school=school;
}
}
结束
写写停停大概也是花费了两天的时间，东西虽然很小，也还有bug，但是还是有点成就感的。我知道IDE肯定不可能用这么蠢得实现方式，但是以我现在的想法只能这样了，还是需要多学点东西，然后我再重构这些代码。