对其做了些优化,但此种sql生成方式仅适用于复杂程度不高的sql,所以实用性不是很高,仅仅是写着玩的,知道点mybatis的注解形式的使用方式,可能以后会逐渐完善起来。第一次写博客,写的简单点。
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package com.bob.config.mvc.mybatis;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* 实体类对应的列
*
* @author jjb
* @create 2017-09-08 14:42
*/
@Documented
@Retention (RetentionPolicy.RUNTIME)
@Target ({ElementType.FIELD, ElementType.METHOD})
public @interface Column {
/**
* 当前属性对应的列名
*
* @return
*/
String value() default "" ;
/**
* 当前属性是不是表必须的
*
* @return
*/
boolean required() default true ;
}
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package com.bob.config.mvc.mybatis;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* 实体类对应的表
*
* @author jjb
* @create 2017-09-08 14:44
*/
@Documented
@Retention (RetentionPolicy.RUNTIME)
@Target ({ElementType.TYPE})
public @interface Table {
String value() default "" ;
/**
* 当前表的主键
*
* @return
*/
String key();
}
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package com.bob.config.mvc.mybatis;
import org.apache.ibatis.annotations.DeleteProvider;
import org.apache.ibatis.annotations.InsertProvider;
import org.apache.ibatis.annotations.Options;
import org.apache.ibatis.annotations.SelectProvider;
import org.apache.ibatis.annotations.UpdateProvider;
/**
* Mybatis基础Mapper
*
* @author jjb
* @create 2017-09-08 14:37
*/
public interface BaseMapper<T> {
/**
* 插入语句
*
* @param bean
* @return
*/
@Options (useGeneratedKeys = true )
@InsertProvider (type = SqlProvider. class , method = "insert" )
public int insert(T bean);
/**
* 删除语句
*
* @param bean
* @return
*/
@DeleteProvider (type = SqlProvider. class , method = "delete" )
public int delete(T bean);
/**
* 更新语句
*
* @param bean
* @return
*/
@UpdateProvider (type = SqlProvider. class , method = "update" )
public int update(T bean);
/**
* 查找语句
*
* @param bean
* @return
*/
@SelectProvider (type = SqlProvider. class , method = "select" )
public T findFirst(T bean);
}
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package com.bob.config.mvc.mybatis;
import java.time.LocalDate;
/**
* Mybatis实体类
*
* @author jjb
* @create 2017-09-08 17:16
*/
@Table (key = "id" )
public class MybatisEntity {
@Column ()
private String id;
@Column ( "USER_NAME" )
private String name;
@Column ()
private Integer age;
private LocalDate date;
@Column ( "ADRESS_NUMBER" )
private Integer userAdressNumber;
public String getId() {
return id;
}
public void setId(String id) {
this .id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this .name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this .age = age;
}
@Column ( "CUR_DATE" )
public LocalDate getDate() {
return date;
}
public void setDate(LocalDate date) {
this .date = date;
}
public Integer getUserAdressNumber() {
return userAdressNumber;
}
public void setUserAdressNumber(Integer userAdressNumber) {
this .userAdressNumber = userAdressNumber;
}
}
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package com.bob.config.mvc.mybatis;
import java.lang.reflect.Field;
import java.util.Map;
/**
* 表到实体的格式化器
*
* @author jjb
* @create 2017-09-08 14:51
*/
public interface TableFormatter {
/**
* 根据属性获取字段名称
*
* @param field
* @return
*/
public String getColumnName(Field field);
/**
* 获取主键属性对应的列名
*
* @return
*/
public String getKeyColumnName(Class<?> clazz);
/**
* 获取主键的属性名称
*
* @param clazz
* @return
*/
public String getKeyFiledName(Class<?> clazz);
/**
* 根据类获取表名称
*
* @param clazz
* @return
*/
public String getTableName(Class<?> clazz);
/**
* 获取一个类的所有属性的映射信息
*
* @param clazz
* @return
*/
public Map<Field, String> getFieldMappings(Class<?> clazz);
}
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package com.bob.config.mvc.mybatis;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeanUtils;
import org.springframework.stereotype.Component;
import org.springframework.util.Assert;
import org.springframework.util.ReflectionUtils;
import org.springframework.util.StringUtils;
/**
* 依据驼峰原则来将表的信息格式化为实体类的信息,在驼峰处改小写同时插入下划线
*
* @author jjb
* @create 2017-09-08 14:55
*/
@Component
public class HumpToUnderLineFormatter implements TableFormatter {
private static final Logger LOGGER = LoggerFactory.getLogger(HumpToUnderLineFormatter. class );
private static final Map<Class<?>, Map<Field, String>> FIELD_TO_COLUMN_MAPPINGS = new HashMap<Class<?>, Map<Field, String>>();
private static final Map<Class, String> CLASS_TO_TABLE_MAPPING = new HashMap<Class, String>();
private static final StringBuilder SB = new StringBuilder();
private static final Object LOCK = new Object();
@Override
public String getColumnName(Field field) {
Assert.notNull(field, "属性不能为空" );
Map<Field, String> mappings = FIELD_TO_COLUMN_MAPPINGS.get(field.getDeclaringClass());
if (mappings == null ) {
synchronized (LOCK) {
mappings = FIELD_TO_COLUMN_MAPPINGS.get(field.getDeclaringClass());
if (mappings == null ) {
mappings = buildMapping(field.getDeclaringClass());
}
}
}
return mappings.get(field);
}
@Override
public String getKeyColumnName(Class<?> clazz) {
Table table = checkClass(clazz);
return getColumnName(ReflectionUtils.findField(clazz,table.key()));
}
@Override
public String getKeyFiledName(Class<?> clazz) {
Table table = checkClass(clazz);
Field field = ReflectionUtils.findField(clazz,table.key());
Assert.state(field != null , "@Table的key()指定的属性必须存在" );
return field.getName();
}
private Table checkClass(Class<?> clazz){
Assert.isTrue(clazz != null , "与Table对应的Class不能为空" );
Table table = clazz.getAnnotation(Table. class );
Assert.isTrue(table != null && StringUtils.hasText(table.key()), "[" +clazz.getName()+ "]必须标识@Table注解且key()不能为空" );
return table;
}
@Override
public String getTableName(Class<?> clazz) {
Assert.notNull(clazz, "类不能为空" );
Assert.isTrue(clazz.isAnnotationPresent(Table. class ), "[" + clazz.getName() + "]类上必须含有@Table注解" );
String name = CLASS_TO_TABLE_MAPPING.get(clazz);
if (name == null ) {
synchronized (LOCK) {
name = CLASS_TO_TABLE_MAPPING.get(clazz);
if (name == null ) {
buildMapping(clazz);
}
}
}
return CLASS_TO_TABLE_MAPPING.get(clazz);
}
@Override
public Map<Field, String> getFieldMappings(Class<?> clazz) {
Assert.isTrue(clazz != null && clazz.isAnnotationPresent(Table. class ), "与Table对应的Class不能为空且必须标识@Table注解" );
Map<Field, String> mappings = FIELD_TO_COLUMN_MAPPINGS.get(clazz);
if (mappings == null ) {
synchronized (LOCK) {
mappings = FIELD_TO_COLUMN_MAPPINGS.get(clazz);
if (mappings == null ) {
mappings = buildMapping(clazz);
}
}
}
return FIELD_TO_COLUMN_MAPPINGS.get(clazz);
}
/**
* 创建实体到表映射
*
* @param clazz
*/
private Map<Field, String> buildMapping(Class<?> clazz) {
buildClassToTableMapping(clazz);
Map<Field, String> mappings = new HashMap<Field, String>();
FIELD_TO_COLUMN_MAPPINGS.put(clazz, mappings);
buildFiledToColumnMapping(clazz, mappings);
buildFiledToColumnMappingWithGetter(clazz, mappings);
return mappings;
}
/**
* 创建类名到表名的名称映射
*
* @param clazz
*/
private void buildClassToTableMapping(Class<?> clazz) {
Table table = clazz.getAnnotation(Table. class );
Assert.notNull(table, "[" + clazz.getName() + "]类上必须有@Table注解" );
CLASS_TO_TABLE_MAPPING.put(clazz, StringUtils.hasText(table.value()) ? table.value() : doFormatWithHunmRule(clazz.getSimpleName()));
}
/**
* 通过Filed建立属性名称到字段名称的映射
*
* @param clazz
* @param mappings
*/
private void buildFiledToColumnMapping(Class<?> clazz, Map<Field, String> mappings) {
ReflectionUtils.doWithLocalFields(clazz, (field) -> {
Column column = field.getAnnotation(Column. class );
if (column != null ) {
if (Modifier.isStatic(field.getModifiers())) {
LOGGER.error( "[{}]注解不适用于静态方法:[{}]" , Column. class .toString(), field);
return ;
}
mappings.put(field, StringUtils.hasText(column.value()) ? column.value() : doFormatWithHunmRule(field.getName()));
}
}
);
}
/**
* 通过getter()建立属性名称到字段名称的映射
*
* @param clazz
* @param mappings
*/
private void buildFiledToColumnMappingWithGetter(Class<?> clazz, Map<Field, String> mappings) {
ReflectionUtils.doWithLocalMethods(clazz, (method) -> {
Column column = method.getAnnotation(Column. class );
if (column != null ) {
if (Modifier.isStatic(method.getModifiers())) {
LOGGER.warn( "[{}]注解不适用于静态方法: [{}]" , Column. class .toString(), method);
return ;
}
if (!method.getName().startsWith( "get" ) || method.getParameterTypes().length > 0 ) {
LOGGER.warn( "[{}]注解只适用于getter方法,而非: [{}]方法" , Column. class .toString(), method);
return ;
}
String fieldName = BeanUtils.findPropertyForMethod(method).getName();
mappings.put(ReflectionUtils.findField(clazz, fieldName),
StringUtils.hasText(column.value()) ? column.value() : doFormatWithHunmRule(fieldName));
}
}
);
}
/**
* 依据驼峰原则格式化属性或者类名称,在驼峰处改小写同时前一位插入下划线,忽略首字母
*
* @param name
* @return
*/
private static String doFormatWithHunmRule(String name) {
Assert.hasText(name, "属性或者类名称不能为空" );
SB.delete( 0 , SB.length());
SB.append(toUpperCase(name.charAt( 0 )));
for ( int i = 1 ; i < name.length(); i++) {
if (isUpperCase(name.charAt(i))) {
SB.append( "_" );
}
SB.append(toUpperCase(name.charAt(i)));
}
return SB.toString();
}
/**
* 将字符转换为大写
*
* @param ch
* @return
*/
private static char toUpperCase( char ch) {
return Character.toUpperCase(ch);
}
/**
* 判断是否为大写
*
* @param ch
* @return
*/
private static boolean isUpperCase( char ch) {
return Character.isUpperCase(ch);
}
}
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package com.bob.config.mvc.mybatis;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import java.util.Map.Entry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.StringUtils;
/**
* Mybatis的SQL语句供应器
*
* @author jjb
* @create 2017-09-08 14:37
*/
public class SqlProvider {
private static final Logger LOGGER = LoggerFactory.getLogger(SqlProvider. class );
private TableFormatter tableFormat = new HumpToUnderLineFormatter();
/**
* 根据Bean对象生成插入SQL语句
*
* @param bean
* @return
*/
public String insert(Object bean) {
Class<?> beanClass = bean.getClass();
String tableName = tableFormat.getTableName(beanClass);
StringBuilder insertSql = new StringBuilder();
List<String> columns = new ArrayList<String>();
List<String> values = new ArrayList<String>();
insertSql.append( "INSERT INTO " ).append(tableName).append( "(" );
try {
for (Entry<Field, String> entry : tableFormat.getFieldMappings(beanClass).entrySet()) {
Field field = entry.getKey();
field.setAccessible( true );
if (field.get(bean) != null ) {
columns.add(entry.getValue());
values.add( "#{" + field.getName() + "}" );
}
}
} catch (Exception e) {
new RuntimeException( "get insert sql has exceptoin:" + e);
}
int columnSize = columns.size();
for ( int i = 0 ; i < columnSize; i++) {
insertSql.append(columns.get(i));
insertSql.append(i != columnSize - 1 ? "," : ") VALUES(" );
}
for ( int i = 0 ; i < columnSize; i++) {
insertSql.append(values.get(i));
insertSql.append(i != columnSize - 1 ? "," : ")" );
}
return insertSql.toString();
}
/**
* 根据Bean对象生成更新SQL语句
*
* @param bean
* @return
*/
public String update(Object bean) {
Class<?> beanClass = bean.getClass();
String tableName = tableFormat.getTableName(beanClass);
StringBuilder updateSql = new StringBuilder();
updateSql.append( " UPDATE " ).append(tableName).append( " SET " );
try {
for (Entry<Field, String> entry : tableFormat.getFieldMappings(beanClass).entrySet()) {
Field field = entry.getKey();
field.setAccessible( true );
if (field.get(bean) != null ) {
updateSql.append(entry.getValue()).append( "=#{" ).append(field.getName()).append( "}," );
}
}
updateSql.deleteCharAt(updateSql.length() - 1 );
} catch (Exception e) {
new RuntimeException( "get update sql is exceptoin:" + e);
}
updateSql.append( " WHERE " ).append(tableFormat.getKeyColumnName(beanClass) + " =#{" + tableFormat.getKeyFiledName(beanClass) + "}" );
return updateSql.toString();
}
/**
* 根据Bean对象生成删除SQL语句
*
* @param bean
* @return
*/
public String delete(Object bean) {
Class<?> beanClass = bean.getClass();
String tableName = tableFormat.getTableName(beanClass);
StringBuilder deleteSql = new StringBuilder();
deleteSql.append( " DELETE FROM " ).append(tableName).append( " WHERE " );
try {
for (Entry<Field, String> entry : tableFormat.getFieldMappings(beanClass).entrySet()) {
Field field = entry.getKey();
field.setAccessible( true );
if (field.get(bean) != null ) {
deleteSql.append(entry.getValue()).append( "=#{" ).append(field.getName()).append( "} AND " );
}
}
deleteSql.delete(deleteSql.length() - 5 , deleteSql.length() - 1 );
} catch (Exception e) {
new RuntimeException( "get delete sql is exceptoin:" + e);
}
return deleteSql.toString();
}
/**
* 生成查询SQL语句
*
* @param bean
* @return
*/
public String select(Object bean) {
Class<?> beanClass = bean.getClass();
String tableName = tableFormat.getTableName(beanClass);
StringBuilder selectSql = new StringBuilder();
List<String> columns = new ArrayList<String>();
List<String> values = new ArrayList<String>();
selectSql.append( "SELECT " );
try {
for (Entry<Field, String> entry : tableFormat.getFieldMappings(beanClass).entrySet()) {
Field field = entry.getKey();
field.setAccessible( true );
selectSql.append(entry.getValue() + "," );
if (field.get(bean) != null ) {
columns.add(entry.getValue());
values.add( "#{" + field.getName() + "}" );
}
}
selectSql.deleteCharAt(selectSql.length() - 1 );
} catch (Exception e) {
new RuntimeException( "get select sql is exceptoin:" + e);
}
selectSql.append( " FROM " ).append(tableName).append( " WHERE " );
int columnSize = columns.size();
for ( int i = 0 ; i < columnSize; i++) {
selectSql.append(columns.get(i)).append( "=" ).append(values.get(i)).append( " AND " );
}
selectSql.delete(selectSql.length() - 5 , selectSql.length() - 1 );
return selectSql.toString();
}
}
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package com.bob.test.concrete.mysqlGenerate;
import java.time.LocalDate;
import com.bob.config.mvc.mybatis.MybatisEntity;
import com.bob.config.mvc.mybatis.SqlProvider;
import org.junit.Before;
import org.junit.Test;
/**
* Mysql基于注解形式的sql语句生成测试
*
* @author jjb
* @create 2017-09-11 11:10
*/
public class MysqlGenerateTest {
private SqlProvider sqlProvider;
private MybatisEntity mybatisEntity;
@Before
public void doBefore(){
sqlProvider = new SqlProvider();
mybatisEntity = new MybatisEntity();
mybatisEntity.setId( "0015415" );
mybatisEntity.setName( "lanboal" );
mybatisEntity.setAge( 28 );
mybatisEntity.setDate(LocalDate.now());
mybatisEntity.setUserAdressNumber( 24 );
}
@Test
public void testInsert(){
String sql = sqlProvider.insert(mybatisEntity);
System.out.println(sql);
}
@Test
public void testUpdate(){
String sql = sqlProvider.update(mybatisEntity);
System.out.println(sql);
}
@Test
public void testDelete(){
String sql = sqlProvider.delete(mybatisEntity);
System.out.println(sql);
}
@Test
public void testSelect(){
String sql = sqlProvider.select(mybatisEntity);
System.out.println(sql);
}
}
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总结
以上所述是小编给大家介绍的 Mybatis基于注解形式的sql语句生成实例代码,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持!
原文链接:http://blog.csdn.net/longdayu4544/article/details/77931795