一个给pojo生成hashcode、equals、toString等方法的工具类

一个给pojo生成hashcode、equals、toString等方法的工具类

package com.kong.coder;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.FilenameFilter;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

public class CodeFactory {

	public static void main(String[] args) {
		String projectPath = "D:\\Workspaces\\MyEclipse 10\\lowcaActivity";
		String packageName = "com.lowca.activity.pojo";
		String[] banedClassNames = {};
		appendCompareMethods(projectPath, packageName, banedClassNames);
	}

	public static void appendCompareMethods(String projectPath,
			String packageName, final String[] banedClassNames) {
		String packagePath = File.separator
				+ packageName.replace(".", File.separator);
		File packageFile = new File(projectPath + File.separator + "src"
				+ packagePath);
		if (!packageFile.exists() || !packageFile.isDirectory()) {
			System.err.println("包文件不存在");
			System.exit(-1);
		}
		File[] pojoFiles = packageFile.listFiles(new FilenameFilter() {

			@Override
			public boolean accept(File dir, String name) {
				boolean isBaned = false;
				for (String banedClassName : banedClassNames) {
					if (name.equals(banedClassName + ".java")) {
						isBaned = true;
						break;
					}
				}
				return !isBaned && name.endsWith(".java");
			}
		});
		if (pojoFiles == null || pojoFiles.length == 0) {
			System.err.println("包文件是空的，找不到pojo");
			System.exit(-1);
		}
		for (File pojoFile : pojoFiles) {
			handlePojoFile(packageName, pojoFile);
		}
	}

	private static void handlePojoFile(String packageName, File pojoFile) {
		String pojoFileName = pojoFile.getName();
		String pojoClassName = packageName + "."
				+ pojoFileName.substring(0, pojoFileName.length() - 5);
		Class<?> pojoClass = null;
		try {
			pojoClass = Class.forName(pojoClassName);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
		Method[] methods = pojoClass.getMethods();
		List<Method> getterList = new ArrayList<Method>();
		// 遍历反射方法组并提取当前类属性的getter方法
		for (Method method : methods) {
			// 过滤与当前类属性无关的get方法
			if (method.getName().startsWith("get")
					&& !method.getName().equals("getClass")) {
				getterList.add(method);
			}
		}
		MethodnameFilter methodnameFilter = new MethodnameFilter() {

			@Override
			public boolean accept(String name) {
				return name.matches("get([A-Z][a-zA-Z])*Id") ? false : true;
			}
		};
		String hashCodeCode = getHashCodeCode(pojoClass, getterList,
				methodnameFilter);
		String equalsCode = getEqualsCode(pojoClass, getterList,
				methodnameFilter);
		String toStringCode = getToStringCode(pojoClass, getterList,
				methodnameFilter);
		String methodsCode = hashCodeCode + equalsCode + toStringCode;

		writeCodeToPojoFile(methodsCode, pojoFile);
	}

	private static void writeCodeToPojoFile(String methodsCode, File pojoFile) {
		BufferedReader br = null;
		BufferedWriter bw = null;
		try {
			FileReader fr = new FileReader(pojoFile);
			br = new BufferedReader(fr);
			String line;
			StringBuffer sb = new StringBuffer();
			while ((line = br.readLine()) != null) {
				sb.append(line + "\r\n");
			}
			int pos = sb.lastIndexOf("}");
			sb.insert(pos, methodsCode);

			FileWriter fw = new FileWriter(pojoFile);
			bw = new BufferedWriter(fw);
			bw.write(sb.toString());
			bw.flush();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				if (br != null)
					br.close();
			} catch (IOException e) {
				e.printStackTrace();
			}

			try {
				if (bw != null)
					bw.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

	private static String getEqualsCode(Class<?> pojoClass,
			List<Method> getterList, MethodnameFilter methodnameFilter) {
		StringBuffer sb = new StringBuffer();
		sb.append("\n\tpublic boolean equals(Object object) {\n");
		sb.append("\t\tif (this == object)\n");
		sb.append("\t\t\treturn true;\n");
		sb.append("\t\tif (!(object instanceof ${class}))\n");
		sb.append("\t\t\treturn false;\n");
		sb.append("\t\tfinal ${class} ${classLowercaseFirst} = (${class}) object;\n");
		for (Method getter : getterList) {
			String getterName = getter.getName();
			if (methodnameFilter != null
					&& !methodnameFilter.accept(getterName))
				continue;
			sb.append("\t\tif (!" + getterName
					+ "().equals(${classLowercaseFirst}." + getterName
					+ "()))\n");
			sb.append("\t\t\treturn false;\n");
		}
		sb.append("\t\treturn true;\n");
		sb.append("\t}\n");
		String code = sb.toString();
		String className = pojoClass.getSimpleName();
		String classNameLowercaseFirst = toLowercaseFirst(className);
		code = code.replaceAll("\\$\\{class\\}", className);
		code = code.replaceAll("\\$\\{classLowercaseFirst\\}",
				classNameLowercaseFirst);
		return code;

	}

	private static String getHashCodeCode(Class<?> pojoClass,
			List<Method> getterList, MethodnameFilter methodnameFilter) {
		StringBuffer sb = new StringBuffer();
		sb.append("\n\tpublic int hashCode() {\n");
		sb.append("\t\tint result;\n");
		boolean first = true;
		for (Method getter : getterList) {
			String getterName = getter.getName();
			if (methodnameFilter != null
					&& !methodnameFilter.accept(getterName))
				continue;
			if (first) {
				first = false;
				sb.append("\t\tresult = " + getterName + "().hashCode();\n");
			} else {
				sb.append("\t\tresult = 29 * result + " + getterName
						+ "().hashCode();\n");
			}
		}
		sb.append("\t\treturn result;\n");
		sb.append("\t}\n");
		String code = sb.toString();
		return code;

	}

	private static String getToStringCode(Class<?> pojoClass,
			List<Method> getterList, MethodnameFilter methodnameFilter) {
		StringBuffer sb = new StringBuffer();
		sb.append("\n\tpublic String toString() {\n");
		boolean first = true;
		for (Method getter : getterList) {
			String getterName = getter.getName();
			if (methodnameFilter != null
					&& !methodnameFilter.accept(getterName))
				continue;
			String filedName = toLowercaseFirst(getterName.substring(3));
			if (first) {
				first = false;
				sb.append("\t\treturn \"${class} [" + filedName + "=\" + "
						+ filedName + "\n");
			} else {
				sb.append("\t\t+ \", " + filedName + "=\" + " + filedName
						+ "\n");
			}
		}
		sb.append("\t\t + \"]\";\n");
		sb.append("\t}\n");
		String code = sb.toString();
		String className = pojoClass.getSimpleName();
		code = code.replaceAll("\\$\\{class\\}", className);
		return code;

	}

	private static String toLowercaseFirst(String pojoClassName) {
		return pojoClassName.substring(0, 1).toLowerCase()
				+ pojoClassName.substring(1);
	}

	interface MethodnameFilter {
		boolean accept(String name);
	}
}