//该工具类可以实现：给定一个指定的数据库表名，即可自动生成对应的java实体类
package com.iamzken.utils;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.net.URL;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Vector;
public class DB2JavaConvertor {
private Connection connection;
private PreparedStatement UserQuery;
/*mysql url的连接字符串*/
private static String url = "jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf-8&useOldAliasMetadataBehavior=true";
//账号
private static String user = "root";
//密码
private static String password = "";
private Vector<String> vector = new Vector<String>();
//mysql jdbc的java包驱动字符串
private String driverClassName = "com.mysql.jdbc.Driver";
//数据库中的表名
String table = "teacher";
//数据库的列名称
private String[] colnames; // 列名数组
//列名类型数组
private String[] colTypes;
public DB2JavaConvertor(){
try {//驱动注册
Class.forName(driverClassName);
if (connection == null || connection.isClosed())
//获得链接
connection = DriverManager.getConnection(url, user, password);
} catch (ClassNotFoundException ex) {
ex.printStackTrace();
System.out.println("Oh,not");
} catch (SQLException e) {
e.printStackTrace();
System.out.println("Oh,not");
}
}
public Connection getConnection() {
return connection;
}
public void setConnection(Connection connection) {
this.connection = connection;
}
public void doAction(){
String sql = "select * from "+table;
try {
PreparedStatement statement = connection.prepareStatement(sql);
//获取数据库的元数据
ResultSetMetaData metadata = statement.getMetaData();
//数据库的字段个数
int len = metadata.getColumnCount();
//字段名称
colnames = new String[len+1];
//字段类型 --->已经转化为java中的类名称了
colTypes = new String[len+1];
for(int i= 1;i<=len;i++){
//System.out.println(metadata.getColumnName(i)+":"+metadata.getColumnTypeName(i)+":"+sqlType2JavaType(metadata.getColumnTypeName(i).toLowerCase())+":"+metadata.getColumnDisplaySize(i));
//metadata.getColumnDisplaySize(i);
colnames[i] = metadata.getColumnName(i); //获取字段名称
colTypes[i] = sqlType2JavaType(metadata.getColumnTypeName(i)); //获取字段类型
}
} catch (SQLException e) {
e.printStackTrace();
}
}
/*
* mysql的字段类型转化为java的类型*/
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("INTEGER")){
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") ||sqlType.equalsIgnoreCase("date")){
return "java.util.Date";
}else if(sqlType.equalsIgnoreCase("image")){
return "Blod";
}
return null;
}
/*获取整个类的字符串并且输出为java文件
* */
public StringBuffer getClassStr(){
String className = table.substring(0,1).toUpperCase()+table.substring(1);
//输出的类字符串
StringBuffer str = new StringBuffer("");
//获取表类型和表名的字段名
this.doAction();
//校验
if(null == colnames && null == colTypes) return null;
str.append(this.getClass().getPackage()+";\r\n\r\n");
//拼接
str.append("public class "+className+" {\r\n");
//拼接属性
for(int index=1; index < colnames.length ; index++){
str.append(getAttrbuteString(colnames[index],colTypes[index]));
}
//拼接get，Set方法
for(int index=1; index < colnames.length ; index++){
str.append(getGetMethodString(colnames[index],colTypes[index]));
str.append(getSetMethodString(colnames[index],colTypes[index]));
}
str.append("}\r\n");
//输出到文件中
String s1 = DB2JavaConvertor.class.getPackage().getName().replace(".", "\\");
String s2 = "src"+File.separator+"main"+File.separator+"java"+File.separator+s1;
String s3 = System.getProperty("user.dir")+File.separator+s2;
File file = new File(s3);
if(!file.exists()){
file.mkdirs();
}
BufferedWriter write = null;
try {
write = new BufferedWriter(new FileWriter(new File(s3+File.separator+className+".java")));
write.write(str.toString());
write.close();
} catch (IOException e) {
e.printStackTrace();
if (write != null)
try {
write.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
return str;
}
/*
* 获取字段字符串*/
public StringBuffer getAttrbuteString(String name, String type) {
if(!check(name,type)) {
System.out.println("类中有属性或者类型为空");
return null;
};
String format = String.format(" private %s %s;\n\r", new String[]{type,name});
return new StringBuffer(format);
}
/*
* 校验name和type是否合法*/
public boolean check(String name, String type) {
if("".equals(name) || name == null || name.trim().length() ==0){
return false;
}
if("".equals(type) || type == null || type.trim().length() ==0){
return false;
}
return true;
}
/*
* 获取get方法字符串*/
private StringBuffer getGetMethodString(String name, String type) {
if(!check(name,type)) {
System.out.println("类中有属性或者类型为空");
return null;
};
String Methodname = "get"+GetTuoFeng(name);
String format = String.format(" public %s %s(){\n\r", new Object[]{type,Methodname});
format += String.format(" return this.%s;\r\n", new Object[]{name});
format += " }\r\n";
return new StringBuffer(format);
}
//将名称首字符大写
private String GetTuoFeng(String name) {
name = name.trim();
if(name.length() > 1){
name = name.substring(0, 1).toUpperCase()+name.substring(1);
}else
{
name = name.toUpperCase();
}
return name;
}
/*
* 获取字段的get方法字符串*/
private Object getSetMethodString(String name, String type) {
if(!check(name,type)) {
System.out.println("类中有属性或者类型为空");
return null;
};
String Methodname = "set"+GetTuoFeng(name);
String format = String.format(" public void %s(%s %s){\n\r", new Object[]{Methodname,type,name});
format += String.format(" this.%s = %s;\r\n", new Object[]{name,name});
format += " }\r\n";
return new StringBuffer(format);
}
public static void main(String[] args) throws IOException {
DB2JavaConvertor bean = new DB2JavaConvertor();
System.err.println(bean.getClassStr());
//System.out.println(ReflectBean.class.getPackage());
//System.out.println(ReflectBean.class.getPackage().getName());
//System.out.println(ReflectBean.class.getResource("").getPath());
// File directory = new File("");//参数为空
// String courseFile = directory.getCanonicalPath() ;
// System.out.println(courseFile);
//
//
// File f = new File(ReflectBean.class.getResource("").getPath());
// System.out.println(f);
//
//
// URL xmlpath = ReflectBean.class.getClassLoader().getResource("");
// System.out.println(xmlpath);
//
// String s1 = directory.getAbsolutePath();
// System.out.println(s1);
/* String s3 = ReflectBean.class.getPackage().getName().replace(".", "\\");
String s2 = System.getProperty("user.dir")+File.separator+s3;
System.out.println(s2);*/
}
}
转载于:https://www.cnblogs.com/iamconan/p/7383525.html
相关资源：实体类转换成数据库表
