一、前言
鉴于新来的同事对于实体bean的命名千奇百怪，于是有了这么个工具类，可以根据数据库中表结构去生成对应实体。只需要再稍作修改即可使用；本文采用的是MYSQL数据库，别的数据库未做尝试；
二、工具代码
2.1 底层代码
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Date;
import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.ResultSetMetaData;
public class GenEntityTool {
private String packageOutPath = "com.user.entity";//指定实体生成所在包的路径
private String authorName = "wangdachui";//作者名字
private String tablename = "";//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[] coldesc;//列描述信息
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.*
//数据库连接
private static final String URL ="jdbc:mysql://127.0.0.1:3306/gy_credit_service_test?useUnicode=true&characterEncoding=UTF-8";
private static final String NAME = "root";
private static final String PASS = "1234567";
private static final String DRIVER ="com.mysql.jdbc.Driver";
/*
* 构造函数
*/
public void GenEntityTool(String localFilePath,String packageOutPath,String dstrTableName){
this.packageOutPath = packageOutPath;
this.tablename = dstrTableName;
//创建连接
Connection con;
//查要生成实体类的表
String sql = "select * from " + this.tablename;
PreparedStatement pStemt = null;
try {
try {
Class.forName(DRIVER);
} catch (ClassNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
con = (Connection) DriverManager.getConnection(URL,NAME,PASS);
pStemt = (PreparedStatement) con.prepareStatement(sql);
ResultSetMetaData rsmd = (ResultSetMetaData) pStemt.getMetaData();
int size = rsmd.getColumnCount(); //统计列
colnames = new String[size];
colTypes = new String[size];
colSizes = new int[size];
for (int i = 0; i < size; i++) {
colnames[i] = rsmd.getColumnName(i + 1);
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;
}
colSizes[i] = rsmd.getColumnDisplaySize(i + 1);
}
String content = parse(colnames,colTypes,colSizes);
try {
File directory = new File("");
String path=this.getClass().getResource("").getPath();
String outputPath = localFilePath +"/"+initcap(this.tablename) + "Entity.java";
FileWriter fw = new FileWriter(outputPath);
PrintWriter pw = new PrintWriter(fw);
pw.println(content);
pw.flush();
pw.close();
} catch (IOException e) {
e.printStackTrace();
}
} catch (SQLException e) {
e.printStackTrace();
} finally{
}
}
/**
* 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();
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");
}
sb.append("import javax.persistence.Column;\r\n");
sb.append("import javax.persistence.Entity;\r\n");
sb.append("import javax.persistence.GeneratedValue;\r\n");
sb.append("import javax.persistence.GenerationType;\r\n");
sb.append("import javax.persistence.Id;\r\n");
sb.append("import javax.persistence.Table;\r\n");
//注释部分
sb.append(" /**\r\n");
sb.append(" * "+tablename+" 实体类\r\n");
sb.append(" * "+new Date()+" "+this.authorName+"\r\n");
sb.append(" */ \r\n");
//注解部分
sb.append("@Entity\r\n");
sb.append("@Table(name = \""+tablename+"\")");
//实体部分
sb.append("\r\n\r\npublic class " + initcap(tablename).replace("_", "")+"Entity implements DBEntity<Long> " + "{\r\n");
processAllAttrs(sb);//属性
sb.append("\r\n\r\n");
processAllMethod(sb);//get set方法
sb.append("}\r\n");
//System.out.println(sb.toString()); r
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("\t//\r\n");
sb.append("\t@Column(name = \""+colnames[i]+"\")\r\n");
sb.append("\tprivate " + sqlType2JavaType(colTypes[i]) + " " + initlower(colnames[i]) + ";\r\n");
sb.append("\t\r\n");
}
}
//处理字段
private String ProcessFile(String fileName)
{
return null;
}
/**
* 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：将输入字符串的首字母改成小写
* @param str
* @return
*/
private String initlower(String str) {
int intFlag=0;
char[] ch = str.toCharArray();
for(int i=0;i<ch.length;i++){
if(ch[i]=='_'){
intFlag=1;
}
if(ch[i] >= 'A' && ch[i] <= 'Z'){
if(intFlag>0){
ch[i] = (char)(ch[i]);
intFlag=0;
}else{
ch[i] = (char)(ch[i] + 32);
}
}
}
return new String(ch).replace("_", "");
}
/**
* 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 "int";
}else if(sqlType.equalsIgnoreCase("bigint")){
return "long";
}else if(sqlType.equalsIgnoreCase("float")){
return "float";
}else if(sqlType.equalsIgnoreCase("decimal") || 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")){
return "String";
}else if(sqlType.equalsIgnoreCase("datetime")){
return "Date";
}else if(sqlType.equalsIgnoreCase("image")){
return "Blod";
}
return null;
}
}
2.2 调用时用的入口方法
public class Test {
public static void main(String[] args) {
try
{
GenEntityTool genEntityTool = new GenEntityTool();
genEntityTool.GenEntityTool("F:\\workspaceforSTS\\gy-credit-db\\src\\main\\java\\com\\byhj\\mysql\\model",
"com.byhj.mysql.model", "open_count_info");//工具空间路径
System.out.println("生成完成！！！");
}catch(Exception ex)
{
System.out.println(ex.toString());
ex.printStackTrace();
}
}
}
三、总结
使用本方法只需要将底层代码放入工具类，配置好后每次调用入口方法就行；运行调用方法后刷新工程即可；