史上最全的springmvc入参传递总结

一、springmvc的优势

1、springmvc能够将URL从http的世界中映射到JAVA世界中，这是框架的核心功能，不得不说确实很强大，但非常的容易理解。

2、springmvc对annotation的完没支持，去掉struts2及springbean繁琐的配置文件，提高开发效率。

3、springmvc结合jackson-core，action层只用关心业务对象的编写，不用关心入参的转换（json->对象）及返回值的转换（对象->json）。

二、Action方法入参的接收

1、入参为简单对象，java.lang.String、java.lang.Integer

 Ajax请求数据

function simpleObject() {
        /*必须与后端参数名保持一致*/
        var data = {
            "name": "张三",
            "age": 12
        };
        var url = "<%=request.getContextPath()%>" + "/v1/simpleObject.action";
        $.ajax({
            url: url,
            type: "POST",
            data: data,
            dataType: "text",
            success: function (result) {
                alert(result);
            }
        });
    }

Action接收

    @RequestMapping(value = "/simpleObject", method = RequestMethod.POST)
    @ResponseBody
    public String simpleObject(String name, Integer age) {
        System.out.println("学生的姓名：" + name + "；年龄：" + age);
        return name + ":" + age;
    }

2、入参为自定义对象，Student

Ajax请求

    function customObject() {
        /*必须与自定义对象的属性名保持一致*/
        var data = {
            "name": "张三",
            "age": 12
        };
        var url = "<%=request.getContextPath()%>" + "/v1/customObject.action";
        $.ajax({
            url: url,
            type: "POST",
            data: data,
            dataType: "text",
            success: function (result) {
                alert(result);
            }
        });
    }

Action接收

    @RequestMapping(value = "/customObject", method = RequestMethod.POST)
    @ResponseBody
    public String customObject(Student student) {
        String name = student.getName();
        Integer age = student.getAge();
        System.out.println("学生的姓名：" + name + "；年龄：" + age);
        return name + ":" + age;
    }

3、入参为简单对象（String, Integer）和自定义对象Student混合

Ajax请求

    function mixedObject() {
        /*name、age必须和Student的属性一致，className、classNum必须和后台参数名一致*/
        var data = {
            "name": "张三",
            "age": 12,
            "className" : "二年级",
            "classNum" : 3
        };
        var url = "<%=request.getContextPath()%>" + "/v1/mixedObject.action";
        $.ajax({
            url: url,
            type: "POST",
            data: data,
            dataType: "text",
            success: function (result) {
                alert(result);
            }
        });
    }

Action接收

    @RequestMapping(value = "/mixedObject", method = RequestMethod.POST)
    @ResponseBody
    public String mixedObject(Student student, String className, Integer classNum) {
        String stuName = student.getName();
        Integer age = student.getAge();
        System.out.println("学生的姓名：" + stuName + "；年龄：" + age);
        System.out.println("年级：" + className + "；班级数：" + classNum);
        return stuName + ":" + age + ":" + className + ":" + classNum;
    }

4、入参为简单对象（String, Integer）列表参数传递

Ajax请求

    function simpleObjectList() {
        /*必须与自定义对象的属性名保持一致*/
        var data = {
            "ids" : [1, 2, 3, 4]
        };
        var url = "<%=request.getContextPath()%>" + "/v1/simpleObjectList.action";
        $.ajax({
            url: url,
            type: "POST",
            data: data,
            dataType: "text",
            success: function (result) {
                alert(result);
            }
        });
    }

Action接收

    @RequestMapping(value = "/simpleObjectList", method = RequestMethod.POST)
    @ResponseBody
    public String simpleObjectList(@RequestParam(value = "ids[]", required = false) List<Integer> ids) {
        //java8新特性，通过流循环集合
        ids.stream().forEach(id ->
            System.out.print(id)
        );
        return "success";
    }

tips:@RequestParam标签的value值需要和前端传递的参数名保持一致，如前端参数名为ids，标签的value的值应为“ids[]”，建议加上required=false属性，因为当前端无ids参数或参数值为空时，不配置required=false属性，springmvc会抛出一个异常。

5、入参为简单对象（String, Integer）、自定义对象Student和简单对象（String, Integer）列表参数传递

Ajax请求

    function mixedSimpleObjectList() {
        /*必须与自定义对象的属性名保持一致*/
        var data = {
            "ids" : [1, 2, 3, 4],
            "name": "张三",
            "age": 12,
            "className" : "二年级",
            "classNum" : 3
        };
        var url = "<%=request.getContextPath()%>" + "/v1/mixedSimpleObjectList.action";
        $.ajax({
            url: url,
            type: "POST",
            data: data,
            dataType: "text",
            success: function (result) {
                alert(result);
            }
        });
    }

Action接收

    @RequestMapping(value = "/mixedSimpleObjectList", method = RequestMethod.POST)
    @ResponseBody
    public String mixedSimpleObjectList(@RequestParam(value = "ids[]", required = false) List<String> ids, Student student,
                                        String className, Integer classNum) {
        ids.stream().forEach(id ->
            System.out.print(id)
        );
        String stuName = student.getName();
        Integer age = student.getAge();
        System.out.println("学生的姓名：" + stuName + "；年龄：" + age);
        System.out.println("年级：" + className + "；班级数：" + classNum);
        return "success";
    }

6、入参为单个自定义对象（Student）列表参数传递，通过数组方式

Ajax请求

    function customObjectList() {
        var studentArray = [];
        var student = new Object();
        student.name = "张三";
        student.age = 12;
        studentArray.push(student);
        var student1 = new Object();
        student1.name = "李四";
        student1.age = 13;
        studentArray.push(student1);
        var url = "<%=request.getContextPath()%>" + "/v1/customObjectList.action";
        $.ajax({
            url: url,
            type: "POST",
            data: JSON.stringify(studentArray),     //将数组转化为json字符串
            dataType: "text",
            contentType: "application/json; charset=utf-8",
            success: function (result) {
                alert(result);
            }
        });
    }

Action接收

    @RequestMapping(value = "/customObjectList", method = RequestMethod.POST)
    @ResponseBody
    public String customObjectList(@RequestBody List<Student> list) {
        try {
            list.stream().forEach(student ->
                System.out.println("name:" + student.getName() + " ;age:" + student.getAge())
            );
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "success";
    }

tips：springmvc支持自定义对象列表的参数传递是使用json串

前端开发人员需要了解两点：

1、HttpServletRequest对象的Content-Type属性，一般情况下，Content-Type的值有以下两种：

Content-Type	含义
application/x-www-form-urlencoded;charser=utf-8	请求参数以form表单的形式提交
application/json;charset=utf-8	请求参数以json传的形式提交

Content-TYpe为application/x-www-form-urlencoded;charser=utf-8是jquery ajax、post等方法的默认行为，大多数的业务，采用这种方式就可以满足我们的需求。

本次请求传递的是json传，所以

2、jquery的JSON.stringify函数的含义：它会将前端参数转变为json传

后端开发人员需要了解：contentType: "application/json; charset=utf-8"

@RequestBody的含义：将json串转变为对象。

7、入参为单个自定义对象列表参数传递，通过DTO的方式

Ajax请求

    function customObjectListByDto() {
        /!*必须与自定义对象的属性名保持一致*!/
        var data = {
            "studentList" : [
                {"name" : "张三", "age" : 12},
                {"name" : "李四", "age" : 13}
            ]
        };
        var url = "<%=request.getContextPath()%>" + "/v1/customObjectListByDto.action";
        $.ajax({
            url: url,
            type: "POST",
            data: JSON.stringify(data),     //将数组转化为json字符串
            dataType: "text",
            contentType: "application/json; charset=utf-8",
            success: function (result) {
                alert(result);
            }
        });
    }

Action接收

    @RequestMapping(value = "/customObjectListByDto", method = RequestMethod.POST)
    @ResponseBody
    public String customObjectListByDto(@RequestBody StudentDto studentDto) {
        try {
            studentDto.getStudentList().stream().forEach(student ->
                    System.out.println("name:" + student.getName() + " ;age:" + student.getAge())
            );
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "success";
    }

tips：自定义对象列表的参数传递，springmvc目前只能支持前端传递json串，后台使用DTO这种方式，对于这种传值方式，后端@RequestBody标签是必不可少的，它会告诉springmvc，需要将前端提交的数据映射到DTO的对象属性上。

8、入参为多个自定义对象列表和简单对象参数传递，通过DTO的方式

Ajax请求

    function mixedCustomObjectListByDto() {
        /!*必须与自定义对象的属性名保持一致*!/
        var data = {
            "schoolName" : "东方完小",
            "year" : 2018,
            "studentList" : [
                {"name" : "张三", "age" : 12},
                {"name" : "李四", "age" : 13}
            ],
            "gradeList" : [
                {"name" : "二年级", "classNum" : 2},
                {"name" : "三年级", "classNum" : 3}
            ]
        };
        var url = "<%=request.getContextPath()%>" + "/v1/mixedCustomObjectListByDto.action";
        $.ajax({
            url: url,
            type: "POST",
            data: JSON.stringify(data),     //将数组转化为json字符串
            dataType: "text",
            contentType: "application/json; charset=utf-8",
            success: function (result) {
                alert(result);
            }
        });
    }

Action接收

    @RequestMapping(value = "/mixedCustomObjectListByDto", method = RequestMethod.POST)
    @ResponseBody
    public String mixedCustomObjectListByDto(@RequestBody StudentDto studentDto) {
        studentDto.getStudentList().stream().forEach(student ->
                System.out.println("name:" + student.getName() + " ;age:" + student.getAge())
        );
        studentDto.getGradeList().stream().forEach(grade ->
                System.out.println("className:" + grade.getName() + " ;classNum:" + grade.getClassNum())
        );
        return "success";
    }

tips：springmvc不支持json到多个DTO对象的mapping映射。
9、StudentDto.java、Student.java、Grade.java

public class StudentDto {
    private String schoolName;

    private Integer year;

    private List<Student> studentList;

    private List<Grade> gradeList;

    public String getSchoolName() {
        return schoolName;
    }

    public void setSchoolName(String schoolName) {
        this.schoolName = schoolName;
    }

    public Integer getYear() {
        return year;
    }

    public void setYear(Integer year) {
        this.year = year;
    }

    public List<Student> getStudentList() {
        return studentList;
    }

    public void setStudentList(List<Student> studentList) {
        this.studentList = studentList;
    }

    public List<Grade> getGradeList() {
        return gradeList;
    }

    public void setGradeList(List<Grade> gradeList) {
        this.gradeList = gradeList;
    }
}

public class Student {
    private Integer id;
    private String name;
    private Integer age;

    public Integer getId() {
        return id;
    }

    public void setId(Integer 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;
    }
}

public class Grade {
    private Integer id;
    private String name;
    private Integer classNum;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getClassNum() {
        return classNum;
    }

    public void setClassNum(Integer classNum) {
        this.classNum = classNum;
    }
}

 代码已上传github：https://github.com/architectboy/ssm-web/releases/tag/ssm-web-1.0

总结不易，转发请表明出处：https://www.cnblogs.com/19940330a/p/9873123.html