参考了http://www.oschina.net/code/snippet_857839_15477
mysql数据库表生成实体类代码如下，稍微改造了一下：
package com.chinamobile.pumpValve.util;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.*;
import java.util.Date;
/**
* on 2016/5/27.
*/
public class GenTableToCode {
private String packageOutPath = "com.xxx.pumpValve.entity";//指定实体生成所在包的路径
private String authorName = "xxxxx";//作者名字
private String tableName = "user";//表名
private String[] colNames; // 列名数组
private String[] colTypes; //列名类型数组
private int[] colSizes; //列名大小数组
private String changeTableNameStr = "";//驼峰转换后的类名
private boolean f_util = false; // 是否需要导入包java.util.*
private boolean f_sql = false; // 是否需要导入包java.sql.*
private boolean f_decimal = false;//是否需要导入java.math.BigDecimal
//数据库连接
private static final String URL ="jdbc:mysql://localhost:3306/pump_valve";
private static final String NAME = "root";
private static final String PASS = "";
private static final String DRIVER ="com.mysql.jdbc.Driver";
/*
* 构造函数
*/
public GenTableToCode(){
}
public void genTableToCode(){
//创建连接
Connection con = null;
//查要生成实体类的表
String sql = "select * from " + tableName;
PreparedStatement pStemt = null;
try {
Class.forName(DRIVER);
con = DriverManager.getConnection(URL,NAME,PASS);
pStemt = con.prepareStatement(sql);
ResultSetMetaData rsmd = pStemt.getMetaData();
int size = rsmd.getColumnCount(); //统计列
colNames = new String[size-4];
colTypes = new String[size-4];
colSizes = new int[size-4];
for (int i = 0; i < size; i++) {
String columnName = rsmd.getColumnName(i+1);
if(!"CREATED_BY".equals(columnName) && !"CREATION_DATE".equals(columnName)
&& !"LAST_UPDATED_BY".equals(columnName) && !"LAST_UPDATE_DATE".equals(columnName)){
//将字符串转换为驼峰样式
String [] columnNameStr =columnName.toLowerCase().split("_");
columnName = "";
for(String column : columnNameStr){
if(columnName.length() == 0){
columnName += column;
}else {
columnName += initCap(column);
}
}
colNames[i] = columnName;
colTypes[i] = rsmd.getColumnTypeName(i + 1);
if(colTypes[i].equalsIgnoreCase("datetime")){
f_util = true;
}
if(colTypes[i].equalsIgnoreCase("image") || colTypes[i].equalsIgnoreCase("text")){
f_sql = true;
}
if(colTypes[i].equalsIgnoreCase("decimal")){
f_decimal = true;
}
colSizes[i] = rsmd.getColumnDisplaySize(i + 1);
}
}
String content = parse(colNames,colTypes,colSizes);
File directory = new File("");
//System.out.println("绝对路径："+directory.getAbsolutePath());
//System.out.println("相对路径："+directory.getCanonicalPath());
String path=this.getClass().getResource("").getPath();
// System.out.println(path);
// System.out.println("src/?/"+path.substring(path.lastIndexOf("/com/", path.length())) );
// String outputPath = directory.getAbsolutePath()+ "/src/"+path.substring(path.lastIndexOf("/com/", path.length()), path.length()) + initCap(tablename) + ".java";
// System.out.println( "\\src\\\\main\\java\\"+this.packageOutPath.replace(".", "\\")+"\\"+initCap(tableName) + ".java");
String outputPath = directory.getAbsolutePath()+ "\\src\\\\main\\java\\"+this.packageOutPath.replace(".", "\\")+"\\"+changeTableNameStr + ".java";
// System.out.println(directory.getAbsolutePath());
File file = new File(outputPath);
if(!file.exists()){
file = new File(directory.getAbsolutePath()+ "\\src\\\\main\\java\\"+this.packageOutPath.replace(".", "\\"),changeTableNameStr + ".java");
file.createNewFile();
}
FileWriter fw = new FileWriter(outputPath);
PrintWriter pw = new PrintWriter(fw);
pw.println(content);
pw.flush();
pw.close();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e1) {
e1.printStackTrace();
} catch (SQLException e1) {
e1.printStackTrace();
}finally{
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
/**
* 传参的方式生成表对应的实体类
* @param tableName
*/
public void genTableToCode(String tableName){
this.tableName = tableName;
genTableToCode();
}
/**
* 功能：生成实体类主体代码
* @param colNames
* @param colTypes
* @param colSizes
* @return
*/
private String parse(String[] colNames, String[] colTypes, int[] colSizes) {
StringBuffer sb = new StringBuffer();
//将表名字符串转换为驼峰样式
String [] tableNameStr =tableName.toLowerCase().split("_");
changeTableNameStr = "";
for(String table : tableNameStr){
changeTableNameStr += initCap(table);
}
sb.append("package " + this.packageOutPath + ";\r\n");
sb.append("\r\n");
//判断是否导入工具包
if(f_util){
sb.append("import java.util.Date;\r\n");
}
if(f_sql){
sb.append("import java.sql.*;\r\n");
}
if(f_decimal){
sb.append("import java.math.BigDecimal;\r\n");
}
DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
sb.append("\r\n");
//注释部分
sb.append("/**\r\n");
sb.append("* Created by "+this.authorName+" on "+df.format(new java.util.Date())+"\r\n");
sb.append("*@Description "+tableName+" 实体类\r\n");
sb.append("*/ \r\n");
//实体部分
sb.append("\r\n\r\npublic class " + initCap(tableName)+ " extends BaseInfo" + "{\r\n");
processAllAttrs(sb);//属性
processAllMethod(sb);//get set方法
sb.append("}\r\n");
//System.out.println(sb.toString());
return sb.toString();
}
/**
* 功能：生成所有属性
* @param sb
*/
private void processAllAttrs(StringBuffer sb) {
for (int i = 0; i < colNames.length; i++) {
sb.append("\tprivate " + sqlType2JavaType(colTypes[i]) + " " + colNames[i] + ";\r\n");
}
}
/**
* 功能：生成所有方法
* @param sb
*/
private void processAllMethod(StringBuffer sb) {
for (int i = 0; i < colNames.length; i++) {
sb.append("\tpublic void set" + initCap(colNames[i]) + "(" + sqlType2JavaType(colTypes[i]) + " " +
colNames[i] + "){\r\n");
sb.append("\tthis." + colNames[i] + "=" + colNames[i] + ";\r\n");
sb.append("\t}\r\n");
sb.append("\tpublic " + sqlType2JavaType(colTypes[i]) + " get" + initCap(colNames[i]) + "(){\r\n");
sb.append("\t\treturn " + colNames[i] + ";\r\n");
sb.append("\t}\r\n");
}
}
/**
* 功能：将输入字符串的首字母改成大写
* @param str
* @return
*/
private String initCap(String str) {
char[] ch = str.toCharArray();
if(ch[0] >= 'a' && ch[0] <= 'z'){
ch[0] = (char)(ch[0] - 32);
}
return new String(ch);
}
/**
* 功能：获得列的数据类型
* @param sqlType
* @return
*/
private String sqlType2JavaType(String sqlType) {
if(sqlType.equalsIgnoreCase("bit")){
return "boolean";
}else if(sqlType.equalsIgnoreCase("tinyint")){
return "byte";
}else if(sqlType.equalsIgnoreCase("smallint")){
return "short";
}else if(sqlType.equalsIgnoreCase("int")){
return "Integer";
}else if(sqlType.equalsIgnoreCase("bigint")){
return "long";
}else if(sqlType.equalsIgnoreCase("float")){
return "float";
}else if(sqlType.equalsIgnoreCase("numeric")
|| sqlType.equalsIgnoreCase("real") || sqlType.equalsIgnoreCase("money")
|| sqlType.equalsIgnoreCase("smallmoney")){
return "double";
}else if(sqlType.equalsIgnoreCase("varchar") || sqlType.equalsIgnoreCase("char")
|| sqlType.equalsIgnoreCase("nvarchar") || sqlType.equalsIgnoreCase("nchar")
|| sqlType.equalsIgnoreCase("text") || sqlType.equalsIgnoreCase("json")){
return "String";
}else if(sqlType.equalsIgnoreCase("datetime")){
return "Date";
}else if(sqlType.equalsIgnoreCase("image")){
return "Blod";
}else if(sqlType.equalsIgnoreCase("decimal")){
return "BigDecimal";
}
return null;
}
public static void main(String[] args) {
GenTableToCode genTableToCode = new GenTableToCode();
List<String> tableNames = new ArrayList<String>();
tableNames.add("user");
tableNames.add("menu");
for(String tableName : tableNames){
genTableToCode.genTableToCode(tableName);
}
}
}
如果是其他数据库，可以修改为相应的数据库连接