将表转javabean(基于mysql)
工做中，老是遇到编写javabean的工做，每次都写得恶心，并且表和字段是下划线的，例如：created_date;而javabean是驼峰的，例如：createdDate。那么，就须要以下的工具类了。java
/**
* 从数据库表反射出实体类，自动生成实体类
* @author lqx
*
*/
public class GenEntityMysql {
private String packageOutPath = "com.funsmart.model";//指定实体生成所在包的路径
private String namespacePrefix= "com.funsmart.dao"; //指定mapper文件的命名空间
private String mapperOutPath= "com.funsmart.mapper"; //指定mapper文件的存放路径
private String authorName = "lqx";//做者名字
private String tablename = "";//表名
private String className = "";//类名
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 boolean f_util = false; // 是否须要导入包java.util.*
private boolean f_sql = false; // 是否须要导入包java.sql.*
private boolean f_jpa = false; // 是否须要生成基于注解的JPA实体对象
//数据库链接
private static final String URL ="jdbc:mysql://127.0.0.1:3306/demo";
private static final String NAME = "root";
private static final String PASS = "root";
private static final String DRIVER ="com.mysql.jdbc.Driver";
/*
* 构造函数
*/
public GenEntityMysql(){
}
/**
* 生成全部的表转成JavaBean
*/
public void genAllTablToBean(){
List<String> list=getTableName();
for(int p=0;p<list.size();p++){
tablename=list.get(p);
className = getClassName(tablename);
//建立链接
Connection con;
//查要生成实体类的表
String sql = "select * from " + tablename;
PreparedStatement pStemt = null;
try {
try {
Class.forName(DRIVER);
} catch (ClassNotFoundException e1) {
e1.printStackTrace();
}
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];
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 outputPath = directory.getAbsolutePath()+ "/src/main/java/"+this.packageOutPath.replace(".", "/")+"/"+initcap(className) + ".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{
// try {
// con.close();
// } catch (SQLException e) {
// // TODO Auto-generated catch block
// e.printStackTrace();
// }
}
}
System.out.println("生成完毕！");
}
/**
* 单表
* 将表转成JavaBean
*/
public void genTablToBean(String tableName){
// List<String> list=getTableName();
// for(int p=0;p<list.size();p++){
tablename=tableName;
className = getClassName(tablename);
//建立链接
Connection con;
//查要生成实体类的表
String sql = "select * from " + tablename;
PreparedStatement pStemt = null;
try {
try {
Class.forName(DRIVER);
} catch (ClassNotFoundException e1) {
e1.printStackTrace();
}
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];
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 outputPath = directory.getAbsolutePath()+ "/src/main/java/"+this.packageOutPath.replace(".", "/")+"/"+initcap(className) + ".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{
// try {
// con.close();
// } catch (SQLException e) {
// // TODO Auto-generated catch block
// e.printStackTrace();
// }
}
// }
System.out.println("生成完毕！");
}
/**
* Java方法 获得当前数据库下全部的表名
* @param con
*/
private List<String> getTableName() {
List<String> list=new ArrayList<String>();
try {
DatabaseMetaData meta = DriverManager.getConnection(URL,NAME,PASS).getMetaData();
ResultSet rs = meta.getTables(null, null, null,new String[]{"TABLE"});
while (rs.next()) {
String tableName = rs.getString(3);
// 获取表名
if(StringUtils.isNotBlank(tableName)){
list.add(tableName);
}
}
}catch(Exception e){
e.printStackTrace();
}
return list;
}
/**
* 将表名转为类名
* @param tableName
* @return
*/
private String getClassName(String tableName){
// 将表名前缀t_去掉
tableName = StringUtils.removeStart(tableName, "t_");
tableName = FieldUtils.camelName(tableName);
return tableName;
}
/**
* 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");
}
//jpa
if(f_jpa){
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\r\n");
}
//注释部分
sb.append("/**\r\n");
sb.append(" * "+className+" 实体类\r\n");
sb.append(" * "+new Date()+"\r\n");
sb.append(" * @"+this.authorName+"\r\n");
sb.append(" */ \r\n");
if(f_jpa){
sb.append("@Entity\r\n");
}
//实体部分
sb.append("public class " + initcap(className) + "{\r\n\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：生成全部属性
* @param sb
*/
private void processAllAttrs(StringBuffer sb) {
for (int i = 0; i < colnames.length; i++) {
String fieldStr = colnames[i];
if(fieldStr.indexOf("_") != -1){
fieldStr = FieldUtils.camelName(fieldStr);
}
sb.append("\tprivate " + sqlType2JavaType(colTypes[i]) + " " + fieldStr + ";\r\n");
}
sb.append("\r\n");
}
/**
* 功能：生成全部方法
* @param sb
*/
private void processAllMethod(StringBuffer sb) {
for (int i = 0; i < colnames.length; i++) {
String fieldStr = colnames[i];
if(fieldStr.indexOf("_") != -1){
fieldStr = FieldUtils.camelName(fieldStr);
}
if(f_jpa){
if(i==0){
sb.append("\t@Id\r\n");
sb.append("\t@GeneratedValue(strategy = GenerationType.AUTO)\r\n");
sb.append("\tpublic " + sqlType2JavaType(colTypes[i]) + " get" + initcap(fieldStr) + "(){\r\n");
}else{
sb.append("\tpublic " + sqlType2JavaType(colTypes[i]) + " get" + initcap(fieldStr) + "(){\r\n");
}
}else{
sb.append("\tpublic " + sqlType2JavaType(colTypes[i]) + " get" + initcap(fieldStr) + "(){\r\n");
}
sb.append("\t\treturn " + fieldStr + ";\r\n");
sb.append("\t}\r\n\r\n");
sb.append("\tpublic void set" + initcap(fieldStr) + "(" + sqlType2JavaType(colTypes[i]) + " " + fieldStr + "){\r\n");
sb.append("\t\tthis." + fieldStr + "=" + fieldStr + ";\r\n");
sb.append("\t}\r\n\r\n");
}
}
/**
* 功能：将输入字符串的首字母改为大写
* @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：得到列的数据类型
* @param sqlType
* @return
*/
private String sqlType2JavaType(String sqlType) {
if(sqlType.equalsIgnoreCase("bit")){
return "boolean";
}else if(sqlType.equalsIgnoreCase("tinyint")){
return "int";
}else if(sqlType.equalsIgnoreCase("smallint")){
return "int";
}else if(sqlType.equalsIgnoreCase("int")||sqlType.equalsIgnoreCase("INT UNSIGNED")){
//INT UNSIGNED无符号整形
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;
}
/**
* 出口
* TODO
* @param args
*/
public static void main(String[] args) {
new GenEntityMysql().genTablToBean("t_city");
}
}
下划线转驼峰的工具类mysql
/**
* 字段的工具类
* 将驼峰转下划线
* 将下划线转驼峰
* User: linqx
* Time: 2015-07-22 22:58
*/
public class FieldUtils {
/**
* 将驼峰式命名的字符串转换为下划线大写方式。若是转换前的驼峰式命名的字符串为空，则返回空字符串。</br>
* 例如：HelloWorld->HELLO_WORLD
* @param name 转换前的驼峰式命名的字符串
* @return 转换后下划线大写方式命名的字符串
*/
public static String underscoreName(String name) {
StringBuilder result = new StringBuilder();
if (name != null && name.length() > 0) {
// 将第一个字符处理成大写
result.append(name.substring(0, 1).toUpperCase());
// 循环处理其他字符
for (int i = 1; i < name.length(); i++) {
String s = name.substring(i, i + 1);
// 在大写字母前添加下划线
if (s.equals(s.toUpperCase()) && !Character.isDigit(s.charAt(0))) {
result.append("_");
}
// 其余字符直接转成大写
result.append(s.toUpperCase());
}
}
return result.toString();
}
/**
* 将下划线大写方式命名的字符串转换为驼峰式。若是转换前的下划线大写方式命名的字符串为空，则返回空字符串。</br>
* 例如：HELLO_WORLD->HelloWorld
* @param name 转换前的下划线大写方式命名的字符串
* @return 转换后的驼峰式命名的字符串
*/
public static String camelName(String name) {
StringBuilder result = new StringBuilder();
// 快速检查
if (name == null || name.isEmpty()) {
// 不必转换
return "";
} else if (!name.contains("_")) {
// 不含下划线，仅将首字母小写
return name.substring(0, 1).toLowerCase() + name.substring(1);
}
// 用下划线将原始字符串分割
String camels[] = name.split("_");
for (String camel : camels) {
// 跳过原始字符串中开头、结尾的下换线或双重下划线
if (camel.isEmpty()) {
continue;
}
// 处理真正的驼峰片断
if (result.length() == 0) {
// 第一个驼峰片断，所有字母都小写
result.append(camel.toLowerCase());
} else {
// 其余的驼峰片断，首字母大写
result.append(camel.substring(0, 1).toUpperCase());
result.append(camel.substring(1).toLowerCase());
}
}
return result.toString();
}
}
就是这样啦。git
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