数据库表转换成javaBean对象小工具

package test.utils;

import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;

/**
* 数据库表转换成javaBean对象小工具(已用了很长时间),
* 1 bean属性按原始数据库字段经过去掉下划线,并大写处理首字母等等.
* 2 生成的bean带了数据库的字段说明.
* 3 各位自己可以修改此工具用到项目中去.
*/
public class GenerateJavaFileUtils {
private String tablename = "";
private String[] colnames;
private String[] colTypes;
private int[] colSizes; // 列名大小
private int[] colScale; // 列名小数精度
private boolean importUtil = false;
private boolean importSql = false;
private boolean importMath = false;

/**
* @param args
*/
public void tableToEntity(String tName) {
tablename = tName;
// 数据连Connection获取,自己想办法就行.
Connection conn = getConnection();
String strsql = "SELECT * FROM " + tablename;// +" WHERE ROWNUM=1"
// 读一行记录;
try {
System.out.println(strsql);
PreparedStatement pstmt = conn.prepareStatement(strsql);
pstmt.executeQuery();
ResultSetMetaData rsmd = pstmt.getMetaData();
int size = rsmd.getColumnCount(); // 共有多少列
colnames = new String[size];
colTypes = new String[size];
colSizes = new int[size];
colScale = new int[size];
for (int i = 0; i < rsmd.getColumnCount(); i++) {
rsmd.getCatalogName(i + 1);
colnames[i] = rsmd.getColumnName(i + 1).toLowerCase();
colTypes[i] = rsmd.getColumnTypeName(i + 1).toLowerCase();
colScale[i] = rsmd.getScale(i + 1);
System.out.println(rsmd.getCatalogName(i + 1));
if ("datetime".equals(colTypes[i])) {
importUtil = true;
}
if ("image".equals(colTypes[i]) || "text".equals(colTypes[i])) {
importSql = true;
}
if (colScale[i] > 0) {
importMath = true;
}
colSizes[i] = rsmd.getPrecision(i + 1);
}
String content = parse(colnames, colTypes, colSizes);
try {
FileWriter fw = new FileWriter(initcap(tablename) + ".java");
PrintWriter pw = new PrintWriter(fw);
pw.println(content);
pw.flush();
pw.close();
} catch (IOException e) {
e.printStackTrace();
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
releaseConnection(conn);
}
}

/**
* 解析处理(生成实体类主体代码)
*/
private String parse(String[] colNames, String[] colTypes, int[] colSizes) {
StringBuffer sb = new StringBuffer();
sb.append(" import java.io.Serializable; ");
if (importUtil) {
sb.append("import java.util.Date; ");
}
if (importSql) {
sb.append("import java.sql.*; ");
}
if (importMath) {
sb.append("import java.math.*; ");
}
// 表注释
processColnames(sb);
sb.append("public class " + initcap(tablename)
+ " implements Serializable { ");
processAllAttrs(sb);
processAllMethod(sb);
sb.append("} ");
System.out.println(sb.toString());
return sb.toString();

}

/**
* 处理列名,把空格下划线'_'去掉,同时把下划线后的首字母大写 要是整个列在3个字符及以内,则去掉'_'后,不把"_"后首字母大写.
* 同时把数据库列名,列类型写到注释中以便查看,
*
* @param sb
*/
private void processColnames(StringBuffer sb) {
sb.append(" /** " + tablename + " ");
String colsiz = "";
for (int i = 0; i < colnames.length; i++) {
colsiz = colSizes[i] <= 0 ? "" : (colScale[i] <= 0 ? "("
+ colSizes[i] + ")" : "(" + colSizes[i] + "," + colScale[i]
+ ")");
sb.append(" " + colnames[i].toUpperCase() + " "
+ colTypes[i].toUpperCase() + colsiz + " ");
char[] ch = colnames[i].toCharArray();
char c = 'a';
if (ch.length > 3) {
for (int j = 0; j < ch.length; j++) {
c = ch[j];
if (c == '_') {
if (ch[j + 1] >= 'a' && ch[j + 1] <= 'z') {
ch[j + 1] = (char) (ch[j + 1] - 32);
}
}
}
}
String str = new String(ch);
colnames[i] = str.replaceAll("_", "");
}
sb.append("*/ ");
}

/**
* 生成所有的方法
*
* @param sb
*/
private void processAllMethod(StringBuffer sb) {
for (int i = 0; i < colnames.length; i++) {
sb.append(" public void set"
+ initcap(colnames[i])
+ "("
+ oracleSqlType2JavaType(colTypes[i], colScale[i],
colSizes[i]) + " " + colnames[i] + "){ ");
sb.append(" this." + colnames[i] + "=" + colnames[i] + "; ");
sb.append(" } ");

sb.append(" public "
+ oracleSqlType2JavaType(colTypes[i], colScale[i],
colSizes[i]) + " get" + initcap(colnames[i])
+ "(){ ");
sb.append(" return " + colnames[i] + "; ");
sb.append(" } ");
}
}

/**
* 解析输出属性
*
* @return
*/
private void processAllAttrs(StringBuffer sb) {
sb.append(" private static final long serialVersionUID = 1L; ");
for (int i = 0; i < colnames.length; i++) {
sb.append(" private "
+ oracleSqlType2JavaType(colTypes[i], colScale[i],
colSizes[i]) + " " + colnames[i] + "; ");
}
sb.append(" ");
}

/**
* 把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);
}

/**
* Oracle
*
* @param sqlType
* @param scale
* @return
*/
private String oracleSqlType2JavaType(String sqlType, int scale, int size) {
if (sqlType.equals("integer")) {
return "Integer";
} else if (sqlType.equals("long")) {
return "Long";
} else if (sqlType.equals("float") || sqlType.equals("float precision"))
return "float";
else if (sqlType.equals("double") || sqlType.equals("double precision")) {
return "Double";
} else if (sqlType.equals("number") || sqlType.equals("decimal")
|| sqlType.equals("numeric") || sqlType.equals("real")) {
return scale == 0 ? (size < 10 ? "Integer" : "Long") : "BigDecimal";
} else if (sqlType.equals("varchar") || sqlType.equals("varchar2")
|| sqlType.equals("char") || sqlType.equals("nvarchar")
|| sqlType.equals("nchar")) {
return "String";
} else if (sqlType.equals("datetime") || sqlType.equals("date")
|| sqlType.equals("timestamp")) {
return "Date";
}
return null;
}

/**
* 自动获取jcbc链接
*/
protected static Connection getConnection() {
Connection localConnection = null;
try {
Class.forName("oracle.jdbc.OracleDriver");
localConnection = DriverManager.getConnection(
"jdbc:oracle:thin:@//localhost:1521/base", "test", "test");
localConnection.setAutoCommit(false);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return localConnection;
}

/**
* 释放jdbc链接
*
* @param conn
*/
protected static void releaseConnection(Connection conn) {
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
conn = null;
}
}

/**
* @param args
*/
public static void main(String[] args) {
GenerateJavaFileUtils t = new GenerateJavaFileUtils();
t.tableToEntity("users");
}

}