mybatisplus转义模糊查询
背景：MySQL模糊查询时，如果前端传了特殊字符而后端没有对特殊字符转义的话，特殊字符就会被识别为SQL中的特殊字符，发挥其特殊字符的含义，如占位符’_‘、’%‘等，如需MySQL将这些字符识别为普通字符，则需要在其前面加上转义符，默认是反斜杠，即变为’_‘、’%'即可。
但是每个查询的地方都加转义，又麻烦又容易遗漏，所以借鉴类似AOP的思想，加一层拦截来解决，如果你的orm框架使用的mybatis-plus，则可以通过实现一个自定义插件解决，mybatis也有类似插件规范。
要求mybatis-plus的版本(starter)>=3.4.0
直接无脑上代码 复制粘贴就行
1、写拦截器插件
import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.lang.Filter;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.core.conditions.AbstractWrapper;
import com.baomidou.mybatisplus.extension.plugins.inner.InnerInterceptor;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import java.sql.SQLException;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
/**
* 自定义mybatis-plus拦截器, 用于转义模糊查询参数中的特殊字符
*
* @author wangjingyang
* @date 2021/6/24 10:33
*/
public class EscapeLikeSqlInterceptor implements InnerInterceptor {
/**
* 点
*/
public static final String DOT = ".";
/**
* 按?分割字符串表达式
*/
public static final String PLACEHOLDER_REGEX = "\\?";
/**
* 按.分割字符串表达式
*/
public static final String DOT_REGEX = "\\.";
/**
* like操作通配符
*/
public static final char LIKE_WILDCARD_CHARACTER = '%';
/**
* like操作通常会存在的占位符形式
*/
public static final String PLACEHOLDER = " ?";
/**
* 条件构造器生成sql特有的参数名前缀
*/
public static final String WRAPPER_PARAMETER_PROPERTY = "ew.paramNameValuePairs.";
/**
* like语句在sql中的字符串
*/
private final String LIKE_SQL = " like ";
private static final String SQL_SPECIAL_CHARACTER = "_%*@|&()[]\"'\\";
/**
* 不应用此拦截器的参数名,方法参数中有此名称的参数则不应用此拦截器
*/
private final String IGNORE = "EscapeLikeSqlIgnore";
@Override
public void beforeQuery(Executor executor, MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) throws SQLException {
if (parameter instanceof Map) {
Map<?, ?> parameterMap = (Map<?, ?>) parameter;
if (parameterMap.containsKey(IGNORE)){
return;
}
}
if (!needEscape(boundSql.getSql())) {
return;
}
escapeSql(boundSql);
}
@Override
public void beforeUpdate(Executor executor, MappedStatement ms, Object parameter) throws SQLException {
if (parameter instanceof Map) {
Map<?, ?> parameterMap = (Map<?, ?>) parameter;
if (parameterMap.containsKey(IGNORE)){
return;
}
}
BoundSql boundSql = ms.getBoundSql(parameter);
if (!needEscape(boundSql.getSql())) {
return;
}
escapeSql(boundSql);
}
/**
* sql是否需要转义
*
* @param sql
* @return
*/
private boolean needEscape(String sql) {
return containLike(sql) && containPlaceholder(sql);
}
/**
* sql是否包含like语句
*
* @param sql
* @return
*/
private boolean containLike(String sql) {
return StrUtil.containsIgnoreCase(sql, LIKE_SQL);
}
/**
* sql是否包含占位符
*
* @param sql
* @return
*/
private boolean containPlaceholder(String sql) {
return StrUtil.contains(sql, PLACEHOLDER);
}
/**
* 参数名是否是条件构造器生成
*
* @param property
* @return
*/
private boolean containWrapper(String property) {
return StrUtil.contains(property, WRAPPER_PARAMETER_PROPERTY);
}
/**
* 参数名是否是对象的嵌套表达式
*
* @param property
* @return
*/
private boolean cascadeParameter(String property) {
return StrUtil.contains(property, DOT);
}
/**
* 转义sql语句中的特殊字符
*
* @param boundSql
*/
@SuppressWarnings("unchecked")
private void escapeSql(BoundSql boundSql) {
String[] split = boundSql.getSql().split(PLACEHOLDER_REGEX);
Object parameter = boundSql.getParameterObject();
Set<String> processedProperty = new HashSet<>();
for (int i = 0; i < split.length; i++) {
// like 通常在末尾
if (StrUtil.lastIndexOfIgnoreCase(split[i], LIKE_SQL) > -1) {
if (parameter instanceof Map) {
// 拿到此位置的"?"对应的参数名
String property = boundSql.getParameterMappings().get(i).getProperty();
// 防止重复转义
if (processedProperty.contains(property)){
continue;
}
Map<Object, Object> parameterMap = (Map<Object, Object>) parameter;
if (containWrapper(property)) {
// 条件构造器构造sql方式
handlerWrapperEscape(property, parameterMap);
} else {
// 自主写sql方式
handlerOriginalSqlEscape(property, parameterMap);
}
processedProperty.add(property);
} else if (parameter instanceof String) {
// 单条件&&不通过条件构造器&&直接写sql&&mapper不写@Param注解,会导致parameter直接为参数值而不是map
// BeanUtil.setFieldValue(boundSql, "parameterObject", SqlUtil.addSalashes((String) parameter));
// 强行反射设置属性,暂不清楚为什么更改parameterObject无效
BeanUtil.setFieldValue(boundSql.getParameterObject(), "value", addSalashes(((String) parameter)).toCharArray());
}
}
}
}
/**
* 处理通过条件构造器构造sql的转义
*
* @param property 参数名
* @param parameterObject 此条sql的参数map
*/
private void handlerWrapperEscape(String property, Map<?, ?> parameterObject) {
String[] keys = property.split(DOT_REGEX);
Object ew = parameterObject.get(keys[0]);
if (ew instanceof AbstractWrapper) {
Map<String, Object> paramNameValuePairs = ((AbstractWrapper<?, ?, ?>) ew).getParamNameValuePairs();
// 拿到参数值
Object paramValue = paramNameValuePairs.get(keys[2]);
if (paramValue instanceof String) {
// 去除首尾%并转义后再拼上%
paramNameValuePairs.put(keys[2], String.format("%%%s%%", addSalashes((String) paramValue, LIKE_WILDCARD_CHARACTER)));
}
}
}
/**
* 处理自己写sql的转义
*
* @param property 参数名
* @param parameterObject 此条sql的参数map
*/
private void handlerOriginalSqlEscape(String property, Map<Object, Object> parameterObject) {
if (cascadeParameter(property)) {
// 级联形式的参数,比如参数是对象中的某个字段的值:filter.name
String[] keys = property.split(DOT_REGEX, 2);
Object parameterBean = parameterObject.get(keys[0]);
Object parameterValue = BeanUtil.getProperty(parameterBean, keys[1]);
if (parameterValue instanceof String) {
BeanUtil.setProperty(parameterBean, keys[1], addSalashes((CharSequence) parameterValue));
}
} else {
// 普通参数名
parameterObject.computeIfPresent(property, (key, value) -> {
if (value instanceof String) {
return addSalashes((CharSequence) value);
}
return value;
});
}
}
private static String addSalashes(CharSequence content, Filter<Character> filter){
if (StrUtil.isEmpty(content)) {
return StrUtil.str(content);
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < content.length(); i++) {
char c = content.charAt(i);
if (filter.accept(c)) {
sb.append('\\');
}
sb.append(c);
}
return sb.toString();
}
private static String addSalashes(CharSequence content, CharSequence applyCharacters){
if (StrUtil.isEmpty(content)) {
return StrUtil.str(content);
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < content.length(); i++) {
char c = content.charAt(i);
if (StrUtil.contains(applyCharacters, c)) {
sb.append('\\');
}
sb.append(c);
}
return sb.toString();
}
private static String addSalashes(CharSequence content){
if (StrUtil.isEmpty(content)) {
return StrUtil.str(content);
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < content.length(); i++) {
char c = content.charAt(i);
if (StrUtil.contains(SQL_SPECIAL_CHARACTER, c)) {
sb.append('\\');
}
sb.append(c);
}
return sb.toString();
}
private static String addSalashes(CharSequence content, char trimFix){
if (content.charAt(0) == trimFix){
content = content.subSequence(1,content.length());
}
if (content.charAt(content.length() - 1) == trimFix){
content = content.subSequence(0,content.length() - 1);
}
return addSalashes(content);
}
}
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如果之前配置了分页插件，注意顺序，自定义插件要放在分页插件前面，否则会导致分页查询的总数对不上查询结果集 ，看日志就能看出就是 count(*) 查询总数的时候特殊字符没来得及加 “\",导致全表查。
@Configuration
public class MybatisPlusConfig {
@Bean
public MybatisPlusInterceptor mybatisPlusInterceptor() {
MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
interceptor.addInnerInterceptor(new EscapeLikeSqlInterceptor());
interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
return interceptor;
}
}