import org.apache.commons.lang.StringUtils;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.*;
public class DBTableToJavaBeanUtil {
public static Connection connection;
//mysql DB连接字符串
private static String DB_URL = "jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8&noDatetimeStringSync=true&serverTimezone=UTC";
private static String DB_USER = "root"; //账号
private static String DB_PASSWD = "root"; //密码
//mysql 驱动全限定名称
public static String DB_DRIVER_CLASS_NAME = "com.mysql.jdbc.Driver";
static {
try {
Class.forName(DB_DRIVER_CLASS_NAME);
if (connection == null || connection.isClosed())
//获得链接
connection = DriverManager.getConnection(DB_URL, DB_USER, DB_PASSWD);
} catch (ClassNotFoundException ex) {
ex.printStackTrace();
System.out.println(ex.getMessage());
} catch (SQLException e) {
e.printStackTrace();
System.out.println(e.getMessage());
}
}
public DBTableToJavaBeanUtil(){
}
/**
* 表元数据
* @param table
* @return
*/
public static Map<String, String> getDBTableMeta(String table){
Map<String, String> colAndTypes = new HashMap();
String sql = "select * from " + table;
try {
PreparedStatement statement = connection.prepareStatement(sql);
//表 元数据
ResultSetMetaData metadata = statement.getMetaData();
//表 列
int len = metadata.getColumnCount();
for(int i= 1;i<= len; i++){
colAndTypes.put(metadata.getColumnName(i), sqlType2JavaType(metadata.getColumnTypeName(i)));
}
} catch (SQLException e) {
e.printStackTrace();
}
return colAndTypes;
}
/**
* sql type <=> java type
* @param sqlType
* @return
*/
public static String sqlType2JavaType(String sqlType) {
switch (sqlType.toLowerCase()){
case "bit": return "boolean";
case "tinyint": return "byte";
case "smallint": return "short";
case "int": return "int";
case "bigint": return "long";
case "float": return "float";
case "decimal":
case "numeric":
case "real":
case "money":
case "smallmoney": return "double";
case "varchar":
case "char":
case "nvarchar":
case "nchar":
case "text": return "String";
case "datetime":
case "date": return "Date";
case "image": return "Blob";
case "timestamp": return "Timestamp";
default: return "String";
}
}
/**
* table 2 class
* @param table 表名称
* @param path 保存类文件路径
*/
public static String tableToClass(String table, String path, String pack){
Map<String, String> colAndTypes = getDBTableMeta(table);
//类字符串
StringBuilder classStr = new StringBuilder();
if(colAndTypes.size() == 0) return "";
if(!isEmpty(pack)){
classStr.append("package " + pack + ";");
}
classStr.append(genImport(colAndTypes.values()));
//驼峰bean名称
classStr.append("public class " + dealName(table, 1) + " {\r\n");
//类字段
for (Map.Entry<String, String> entry : colAndTypes.entrySet()) {
classStr.append(genFieldStr(entry.getKey(), entry.getValue()));
}
//get，Set
for (Map.Entry<String, String> entry : colAndTypes.entrySet()) {
classStr.append(genGetMethodStr(entry.getKey(), entry.getValue()));
classStr.append(genSetMethodStr(entry.getKey(), entry.getValue()));
}
classStr.append("}\r\n");
//保存
path = isEmpty(path)?"":path;
File file = new File(path + dealName(table, 1) + ".java");
try(BufferedWriter write = new BufferedWriter(new FileWriter(file))) {
write.write(classStr.toString());
write.close();
} catch (IOException e) {
e.printStackTrace();
}
return classStr.toString();
}
public static String genImport(Collection<String> types){
StringBuilder sb = new StringBuilder();
if(types.contains("Date")){
sb.append("import java.util.Date;\r\n");
}
if(types.contains("Blob")){
sb.append("import java.sql.Blob;\r\n");
}
if(types.contains("Timestamp")){
sb.append("import java.sql.Timestamp;\r\n");
}
return sb.toString();
}
/**
* 属性构造
* @param name
* @param type
* @return
*/
public static String genFieldStr(String name, String type) {
if(isEmpty(name) || isEmpty(type)) {
return "";
}
return String.format(" private %s %s;\n\r", new String[]{type, dealName(name, 0)});
}
public static boolean isEmpty(String str){
if(str == null || str == "") return true;
return false;
}
/**
* get method construct
* @param name
* @param type
* @return
*/
private static String genGetMethodStr(String name, String type) {
if(isEmpty(name) || isEmpty(type)) {
return "";
}
StringBuilder sb = new StringBuilder();
sb.append(String.format(" public %s get%s(){\n\r", type, dealName(name, 1)));
sb.append(String.format(" return this.%s;\r\n", dealName(name, 0)));
sb.append(" }\r\n");
return sb.toString();
}
/**
* 驼峰名称处理
* @param name
* @param type
* @return
*/
public static String dealName(String name, int type) {
String[] names = StringUtils.split(StringUtils.trim(name), "_");
if(names.length > 0){
StringBuilder sb= new StringBuilder();
for (String s : names) {
sb.append(StringUtils.upperCase(StringUtils.substring(s, 0, 1)));
sb.append(StringUtils.lowerCase(StringUtils.substring(s, 1)));
}
if(type == 0){
sb.replace(0, 1, StringUtils.lowerCase(sb.substring(0, 1)));
}
return sb.toString();
}
return "";
}
/**
* set method contruct
* @param name
* @param type
* @return
*/
public static String genSetMethodStr(String name, String type) {
if(isEmpty(name) || isEmpty(type)) {
return "";
}
String fieldName = dealName(name, 0);
StringBuilder sb = new StringBuilder();
sb.append(String.format(" public void set%s(%s %s){\n\r", dealName(name, 1), type, fieldName));
sb.append(String.format(" this.%s = %s;\r\n", fieldName, fieldName));
sb.append(" }\r\n");
return sb.toString();
}
public static void close(){
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
System.out.println(DBTableToJavaBeanUtil.tableToClass("book", "d:\\", null));
close();
}
}
